JP2013069385A - Optical disk drive and focus control method - Google Patents

Abstract

A focus control and tracking control suitable for an optical disc having a servo layer and a recording layer is provided.
Focus is applied to a first laser beam and a second laser beam from a state where focus control of a servo layer focus control unit for a servo layer and focus control of a recording layer focus control unit for a recording layer are not started. When performing the pull-in, the timing at which the servo layer focus control unit starts the focus control on the servo layer so as to perform the focus pull-in to the servo layer of the second laser light is the focus on the recording layer of the first laser light. The focus control timing is controlled to be after the timing at which the recording layer focus control unit starts focus control on any one of the recording layers so as to perform pull-in.
[Selection] Figure 1

Description

  The present invention relates to an optical disc apparatus for reproducing information from an optical disc using a laser or recording information on an optical disc.

  In recent years, optical discs having three or four recording layers have been developed in order to increase the recording capacity of Blu-ray Disc (TM) standard optical discs. In the future, as a method for realizing a further increase in capacity of the optical disc, it is conceivable to perform recording / reproduction on an optical disc having a larger number of recording layers.

  For example, in Patent Document 1, a layer for performing tracking servo control having a physical groove structure (hereinafter referred to as a servo layer) and a layer for performing recording / reproduction without a physical groove structure (hereinafter referred to as a recording layer). An optical disc (hereinafter referred to as a grooveless disc) is disclosed, and an increase in manufacturing cost can be suppressed even when a large number of recording layers are stacked.

  Further, according to Patent Document 2, the servo laser light optical system is configured so that the spot size of the servo laser light on the servo layer is substantially equal to the spot size of the recording laser light on the predetermined recording layer. A focus adjustment device that sets a numerical aperture and sets focus positions of the servo laser beam and the recording laser beam by the objective lens apart from each other in a film thickness direction of the plurality of recording layers, A recording / reproducing apparatus is disclosed.

  According to Patent Document 3, a spherical aberration correction 50% driving process (step S116) is added after the tracking servo-off process, and a spherical aberration correction 50% driving process (step S117) is added before the tracking servo-on process in step S113. A focused focus jump method is disclosed. Furthermore, in the description of Patent Document 3, the entire driving amount (100%) of spherical aberration correction is divided into 50%: 50% in step S116 and step S117 in FIG. 8, respectively. It is good also as a division ratio. Further, there is a description that if the focus servo control is not removed, step S116 may be omitted and 0%: 100% may be omitted, and conversely, step S117 may be omitted and 100%: 0%.

  Further, Patent Document 4 discloses a focus jump method in which the objective lens 5 is driven in the focus direction, and the spherical aberration correction mechanism 7 is gradually driven from the current position to a spherical aberration correction position suitable for a desired recording / reproducing surface. Has been.

JP 2002-63738 A JP 2009-104717 A JP 2011-48868 A JP 2007-109285 A

  As a problem when recording / reproducing with respect to an optical disc having a servo layer and a recording layer, there are operation methods related to focus control for the servo layer and focus control for the recording layer. As an example thereof, there is a focus pull-in operation in which the focus control for the servo layer and the focus control for the recording layer are both shifted from the state where the focus control is not performed to the state where the two focus controls are operating.

  Another example is a focus jump operation in which a light spot irradiated to a recording layer is moved to another recording layer. Furthermore, the order in which the above two focus control and tracking control are operated is also a problem.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical disc apparatus that enables focus control and tracking control suitable for an optical disc having a servo layer and a recording layer.

  The above-mentioned subject is improved by the composition as described in a claim as an example.

  According to the present invention, it is possible to perform focus control and tracking control suitable for an optical disc having a servo layer and a recording layer.

1 is a configuration diagram illustrating an optical disc apparatus according to a first embodiment. 3 is a flowchart of the entire setup process in the first embodiment. 6 is a flowchart of focus pull-in processing in Embodiment 1. FIG. 6 is a waveform diagram for explaining a focus pull-in process in Embodiment 1. FIG. 6 is a waveform diagram for explaining a focus pull-in process in Embodiment 1. 9 is a flowchart of focus jump processing in Embodiment 2. FIG. 10 is a waveform diagram illustrating a focus jump process from the L0 layer to the L1 layer in the second embodiment. FIG. 10 is a waveform diagram illustrating focus jump processing from the L1 layer to the L0 layer in the second embodiment. FIG. 10 is a waveform diagram illustrating a focus jump process from the L0 layer to the L1 layer in the second embodiment. 10 is a flowchart of focus jump processing in Embodiment 3. 10 is a flowchart of focus jump processing in Embodiment 4. FIG. 10 is a waveform diagram illustrating focus jump processing from the L0 layer to the L1 layer in the fourth embodiment. 10 is a flowchart of focus jump processing in Embodiment 5. FIG. 10 is a waveform diagram illustrating focus jump processing from the L0 layer to the L1 layer in the fifth embodiment. 2 is a diagram showing the structure of an optical disc 101. FIG. It is a wave form diagram explaining the negative feedback area | region of a SFE signal. It is a wave form diagram explaining operation | movement of the aberration correction element 1209 at the time of a focus jump.

  Hereinafter, embodiments for carrying out the present invention will be described using the drawings.

  Example 1 of the present invention will be described below. FIG. 1 is a block diagram showing the configuration of the optical disk apparatus according to this embodiment. The optical disk apparatus records or reproduces information by irradiating the optical disk 101 mounted on the apparatus with laser light, and a host (not shown) such as a PC (Personal Computer) through an interface such as SATA (Serial Advanced Technology Attachment). Communicate.

  The structure of the optical disc 101 is illustrated in FIG. The optical disc 101 has a servo layer having a track (tracking guide groove) structure and N recording layers (N ≧ 1, N is a natural number) not having a track (tracking guide groove) structure. In the following description, it is assumed that the recording layer of the optical disc 101 is formed with a recording film and, as an example, has four recording layers (N = 4). Further, as shown in FIG. 15, the recording layer farthest from the disk surface is referred to as L0, and the remaining recording layers are referred to as L1, L2, and L3 in order of approaching the disk surface. The optical disk apparatus can generate a laser spot on each of the recording layer and the servo layer by the objective lens 1211.

  The optical disk apparatus in this embodiment includes an optical pickup 102, a signal processing circuit 103, a spindle motor 104, a servo error signal generation circuit 105, a reproduction signal processing circuit 106, a spindle driving circuit 107, and an actuator driving circuit 108. , A relay lens driving circuit 109, an aberration correction element driving circuit 110, a slider motor 111, and a slider driving circuit 112.

  The signal processing circuit 103 is a circuit that performs various types of signal processing of the optical disk device, and operates with the potential Vref as a reference. The signal processing circuit 103 includes a system control circuit 1301, a recording layer focus control circuit 1302, a switch 1303, an adder 1304, a recording layer focus drive voltage generation circuit 1305, a servo layer focus control circuit 1306, and a switch 1307. , An adder 1308, a servo layer focus drive voltage generation circuit 1309, a tracking control circuit 1310, a switch 1311, a slider control circuit 1312, and a spindle control circuit 1313. A system control circuit 1301 is a circuit that controls various operations performed by the optical disc apparatus, and for example, a general CPU (Central Processing Unit) can be used.

  The optical disk 101 is rotated at a predetermined rotation speed by a spindle motor 104. The spindle motor 104 is controlled by a spindle control circuit 1313 that has received a command signal from a system control circuit 1301 mounted on the signal processing circuit 103. The signal output from the spindle control circuit 1313 is amplified by the spindle drive circuit 107, and the amplified signal is supplied to the spindle motor 104.

  As described above, the spindle control circuit 1313 in this embodiment performs control so as to rotate at a predetermined rotational speed regardless of the radial position based on the output signal of the spindle motor 104. Such a rotation method is called CAV control.

  The optical pickup 102 includes two optical systems having different wavelengths such as 405 nm and 650 nm.

  First, a 405 nm optical system will be described. The laser power control circuit 1201 is controlled by the system control circuit 1301 and outputs a current for driving the laser diode 1202. This driving current is applied with high frequency superposition of several hundred MHz in order to suppress laser noise. The laser diode 1202 emits laser light having a wavelength of 405 nm with a waveform corresponding to the drive current. The emitted laser light is converted into parallel light by the collimator lens 1203, partly reflected by the beam splitter 1204, and condensed on the power monitor 1206 by the condenser lens 1205. The power monitor 1206 feeds back a current or voltage corresponding to the intensity of the laser light to the system control circuit 1301. As a result, the intensity of the laser beam condensed on the recording layer of the optical disc 101 is maintained at a desired value such as 2 mW. On the other hand, the laser beam that has passed through the beam splitter 1204 is reflected by the polarization beam splitter 1207, the convergence / divergence is controlled by the aberration correction element 1209 driven by the aberration correction element driving circuit 110, and the dichroic mirror 1208 is transmitted. The aberration correction element 1209 is an optical element for correcting aberrations such as spherical aberration. The dichroic mirror 1208 is an optical element that reflects light of a specific wavelength and transmits light of other wavelengths. Here, it is assumed that light having a wavelength of 405 nm is transmitted and light having a wavelength of 650 nm is reflected. The laser beam that has passed through the dichroic mirror 1208 becomes circularly polarized light by the quarter-wave plate 1210 and is focused on the recording layer of the optical disc 101 by the objective lens 1211. The position of the objective lens 1211 is controlled by, for example, an actuator 1212 as objective lens driving means for driving the objective lens. The intensity of the laser light reflected by the optical disc 101 is modulated according to information recorded on the optical disc 101. The light is linearly polarized by the ¼ wavelength plate 1210, passes through the dichroic mirror 1208 and the aberration correction element 1209, and passes through the polarization beam splitter 1207. The transmitted laser light is condensed on the detector 1214 by the condenser lens 1213. The detector 1214 detects the intensity of the laser beam and outputs a signal corresponding to the intensity to the servo error signal generation circuit 105 and the reproduction signal processing circuit 106.

  The servo error signal generation circuit 105 uses a recording layer focus error signal (hereinafter referred to as an R_FE signal) for use in focus control for the recording layer from the signals output from the detector 1214 and the detector 1223, and is used for focus control for the servo layer. Servo layer focus error signal (hereinafter referred to as S_FE signal) and tracking error signal (hereinafter referred to as TE signal) for use in tracking control are generated. Each error signal is output with reference to the potential Vref. Each error signal output from the servo error signal generation circuit 105 is input to the system control circuit 1301 and used for timing detection in the focus pull-in process, for example.

  The focus control in the 405 nm optical system is performed on any one of the recording layers. The recording layer focus control circuit 1302 performs gain and phase compensation for the recording layer focus error signal R_FE in response to a command signal from the system control circuit 1301, and outputs a drive signal for performing focus control on the recording layer. The drive signal output from the recording layer focus control circuit 1302 is input to the actuator drive circuit 108 via the switch 1303 and the adder 1304.

  The switch 1303 selects and outputs the output signal of the recording layer focus control circuit 1302 or the reference potential Vref based on the R_FON signal output from the system control circuit 1301. When the high level is input as the R_FON signal, the switch 1303 selects the terminal a, and the output signal of the recording layer focus control circuit 1302 is output to the actuator drive circuit 108 via the adder 1304. On the other hand, when the Low level is input as the R_FON signal, the switch 1303 selects the terminal b and outputs the reference potential Vref. As a result, the R_FON signal is a signal for instructing on / off of focus control for the recording layer. The switch 1303 functions as a switch for switching on and off the focus control for the recording layer. When the R_FON signal is switched from Low to High, the focus control for the recording layer is turned on, and this operation is called a focus pull-in operation.

  The recording layer focus drive voltage generation circuit 1305 outputs a predetermined voltage in response to a command signal from the system control circuit 1301. The recording layer focus drive voltage generation circuit 1305 outputs, for example, a sweep voltage in the focus sweep operation and a jump voltage at the time of focus jump. For example, a general CPU can be used as the recording layer focus drive voltage generation circuit 1305.

  The adder 1304 adds the output signal of the recording layer focus drive voltage generation circuit 1305 and the output signal of the switch 1303, and outputs the sum as a recording layer focus drive signal R_FOD to the actuator drive circuit 108. The actuator drive circuit 108 drives an actuator 1212 configured to operate integrally with the objective lens 1211 in a direction perpendicular to the disk surface in accordance with the recording layer focus drive signal R_FOD. As described above, the recording layer focus control circuit 1302 and the actuator driving circuit 108 operate so that the focus of the laser beam having a wavelength of 405 nm irradiated on the optical disc 101 is always focused on the surface of the recording layer of the optical disc 101. In addition, focus control is performed on the recording layer. In this specification, this control system is called a recording layer focus control system.

  Next, a 650 nm optical system will be described. Similar to the 405 nm optical system, the laser power control circuit 1201 drives the laser diode 1215, and the laser diode 1215 emits laser light having a wavelength of 650 nm. A part of the laser light passes through a collimator lens 1216, a beam splitter 1217, and a condenser lens 1218, and the power is monitored by a power monitor 1219. By feeding back the monitored power to the system control circuit 1301, the intensity of the laser light focused on the servo layer of the optical disc 101 is maintained at a desired power, such as 3 mW. The laser beam that has passed through the beam splitter 1217 passes through the polarization beam splitter 1220, and convergence / divergence is controlled by the relay lens 1221. The laser light that has passed through the relay lens 1221 is reflected by the dichroic mirror 1208, passes through the quarter-wave plate 1210, and is condensed on the servo layer of the optical disc 101 by the objective lens 1211. The laser beam reflected by the optical disc 101 is reflected by the polarization beam splitter 1220 and condensed on the detector 1223 by the condenser lens 1222.

  Focus control in the 650 nm optical system is performed on the servo layer. Focus control for the servo layer is performed by a servo layer focus control circuit 1306, a switch 1307, an adder 1308, and a servo layer focus drive voltage generation circuit 1309, which has a configuration similar to the focus control for the recording layer described above.

  The servo layer focus control circuit 1306 compensates the servo layer focus error signal R_FE for gain and phase in response to a command signal from the system control circuit 1301, and outputs a drive signal for performing focus control on the servo layer. The drive signal output from the servo layer focus control circuit 1306 is input to the relay lens drive circuit 109 via the switch 1307 and the adder 1308.

  The switch 1307 selects and outputs the output signal of the servo layer focus control circuit 1306 or the reference potential Vref based on the S_FON signal output from the system control circuit 1301. When the high level is input as the S_FON signal, the switch 1307 selects the terminal c, and the output signal of the servo layer focus control circuit 1306 is output to the relay lens driving circuit 109 via the adder 1308. On the other hand, when the Low level is input as the R_FON signal, the switch 1307 selects the terminal d and outputs the reference potential Vref.

  As a result, the S_FON signal is a signal for instructing on / off of focus control for the servo layer. The switch 1307 functions as a switch for switching on / off the focus control for the servo layer. When the S_FON signal is switched from Low to High, the focus control for the servo layer is turned on, and this operation is called a focus pull-in operation.

  The servo layer focus drive voltage generation circuit 1309 outputs a predetermined voltage in response to a command signal from the system control circuit 1301. For example, the servo layer focus drive voltage generation circuit 1309 outputs a sweep voltage in the focus sweep operation. As the servo layer focus drive voltage generation circuit 1309, for example, a general CPU can be used.

  The adder 1308 adds the output signal of the servo layer focus drive voltage generation circuit 1309 and the output signal of the switch 1307, and outputs the result to the relay lens drive circuit 109 as the servo layer focus drive signal S_FOD.

  The relay lens driving circuit 109 drives a relay lens 1221 mounted in the optical pickup 102. By driving the relay lens 1221, the position of the focal point of the laser beam focused on the servo layer can be displaced, and the difference in position between the recording layer and the servo layer can be compensated.

  As described above, the servo layer focus control circuit 1306 and the relay lens drive circuit 109 operate, so that the focus of the laser beam having a wavelength of 650 nm irradiated on the optical disc 101 is always focused on the surface of the servo layer of the optical disc 101. As described above, focus control for the servo layer is performed. In this specification, this control system is called a servo layer focus control system.

  Next, tracking control in the present embodiment will be described. The tracking control circuit 1310 compensates the tracking error signal TE for gain and phase in response to a command signal from the system control circuit 1301, and outputs a drive signal for performing tracking control. The drive signal output from the tracking control circuit 1310 is input to the actuator drive circuit 108 via the switch 1311.

  The switch 1311 selects the output signal of the tracking control circuit 1310 or the reference potential Vref based on the TON signal output from the system control circuit 1301, and outputs it to the actuator drive circuit 108 as the tracking drive signal TRD. When the high level is input as the TON signal, the switch 1311 selects the terminal e, and the output signal of the tracking control circuit 1310 is output to the actuator drive circuit 108. On the other hand, when the Low level is input as the TON signal, the switch 1311 selects the terminal f and outputs the reference potential Vref.

  As a result, the TON signal becomes a signal for instructing on / off of the tracking control. The switch 1311 functions as a switch for switching tracking control on and off. Tracking control is turned on when the TON signal is switched from Low to High, and this operation is called a track pull-in operation.

  The actuator drive circuit 108 drives the actuator 1212 in a direction parallel to the disk surface in accordance with the tracking drive signal TRD, thereby driving the objective lens 1211 in the disk radial direction. As described above, the actuator drive circuit 108 in this embodiment includes a circuit that drives in the focus direction and a circuit that drives in the tracking direction. As described above, tracking control is performed by the tracking control circuit 1310 and the actuator drive circuit 108 operating.

  The reproduction signal processing circuit 106 performs equalization processing on the electric signals detected by the detector 1214 and the detector 1223 and outputs the result as a reproduction signal. The reproduction signal is input to the system control circuit 1301, and processing such as amplification, equalization, and decoding is performed inside the system control circuit 1301, and information read from the optical disc 101 (recorded data, current address information, etc.) is generated. To do.

  When the slider control circuit 1312 receives a command signal from the system control circuit 1301, it outputs a slider drive signal for driving the slider motor 111 based on the average value of the output signals of the tracking control circuit 1310. The slider drive circuit 112 drives the slider motor 111 according to the slider drive signal so that the objective lens 1211 always operates in the vicinity of the neutral position where the lens shift is zero even when the track continues to follow the track. The optical pickup 102 is transported in the disk radial direction. The aberration correction element drive circuit 110 generates a drive voltage for driving the aberration correction element 1209 in response to a command signal from the system control circuit 1301 to drive the aberration correction element 1209.

  FIG. 2 shows a flowchart of the entire setup process when the optical disc 101 is inserted into the optical disc apparatus of the present embodiment. When the optical disc 101 is inserted into the optical disc apparatus, a setup process is started (step S201). In the setup process, the optical disk apparatus first performs a disk recognition process (step S202). In the disc recognition process, the presence / absence of the disc and the disc type are confirmed. In this operation, for example, the system control circuit 1301 instructs the laser power control circuit 1201 to emit one of the laser diodes, and at the same time, the system control circuit 1301 instructs the recording layer focus drive voltage generation circuit 1305 to perform the objective lens 1211. Can be realized by driving in a direction perpendicular to the disk surface. As a result of irradiating the optical disc 101 with laser light, reflected light is detected by any detector, and recognition can be performed using the detected signal.

  Next, the optical disc apparatus performs an aberration correction element driving process (step S203). This is preparation for a focus pull-in process, which will be described later, and the aberration correction element 1209 is driven so that a predetermined aberration correction amount is obtained. Next, the optical disc apparatus performs a relay lens driving process (step S204). This is preparation for a focus pull-in process described later, and the relay lens 1221 is driven so that the position of the relay lens becomes a predetermined position. After step S204, focus pull-in processing is performed on the optical disc 101 (step S205). Details of this processing will be described later.

  Next, the optical disc apparatus performs a track pull-in process on the tracks formed on the servo layer of the optical disc 101 (step S206). In this process, the system control circuit 1301 changes the TON signal from Low level to High level. As a result, the switch 1311 is switched and the tracking control is turned on.

  Next, adjustment processing for optimizing various parameters in the optical disc apparatus is performed on the inserted optical disc 101 (step S207). Examples of the various parameters include adjusting the amplification factor of the amplifier included in the recording layer focus control circuit 1302 and the tracking control circuit 1310 according to the reflectance of the optical disc 101.

  After performing various adjustment processes S207, a management information read process is performed to read the management information recorded on the optical disc 101 (step S208). When step S208 is completed, the setup process ends (step S209). Thus, it becomes possible to record or reproduce information in response to an instruction from the host. The timing of the adjustment process S207 is not limited to this, and a part of the adjustment process may be performed before the focus pull-in process S205 or after the management information read process S208.

  Hereinafter, the operation of the system control circuit 1301 in the present embodiment will be described using the flowchart of the focus pull-in process S205 shown in FIG. When the focus pull-in process is started (step S301), the system control circuit 1301 instructs the recording layer focus drive voltage generation circuit 1305 to sweep the objective lens (step S302). When the recording layer focus drive voltage generation circuit 1305 receives the objective lens sweep instruction, it outputs a voltage of a predetermined pattern to drive the objective lens 1211 in a direction perpendicular to the disk surface. Subsequently, the system control circuit 1301 monitors the R_FE signal output from the servo error signal generation circuit 105 and determines whether it is the recording layer focus pull-in timing (step S303).

  If it is not the recording layer focus pull-in timing (No in step S303), the process returns to step S303 and waits until the recording layer focus pull-in timing is reached. When it is the recording layer focus pull-in timing (Yes in Step S303), the system control circuit 1301 instructs the focus pull-in to the recording layer by setting the R_FON signal High (Step S304). Further, the recording layer focus drive voltage generation circuit 1305 is instructed to stop the objective lens sweep (step S305).

  Subsequently, the system control circuit 1301 instructs the servo layer focus drive voltage generation circuit 1309 to perform a relay lens sweep (step S306). When receiving the relay lens sweep instruction, the servo layer focus drive voltage generation circuit 1309 outputs a voltage having a predetermined pattern to drive the relay lens 1221. Subsequently, the system control circuit 1301 monitors the S_FE signal output from the servo error signal generation circuit 105 to determine whether it is the servo layer focus pull-in timing (step S307). If it is not the servo layer focus pull-in timing (No in step S307), the process returns to step S307 and waits until the servo layer focus pull-in timing is reached. When it is the servo layer focus pull-in timing (Yes in step S307), the system control circuit 1301 instructs the focus pull-in process for the servo layer by setting the S_FON signal to high (step S308). Further, the servo layer focus drive voltage generation circuit 1309 is instructed to stop the relay lens sweep (step S309). Thus, the focus pull-in process is completed (step S310).

  Next, the operation of each part in the focus pull-in process of this embodiment will be described with reference to FIG. FIG. 4 is a waveform diagram showing signals at various parts during the focus pull-in process. Among the waveforms shown in FIG. 4, (a) to (d) are signals relating to the recording layer, and (e) to (h) are signals relating to the servo layer. 4A is an R_FE signal, FIG. 4B is an output signal of the recording layer focus drive voltage generation circuit 1305, FIG. 4C is an R_FON signal, and FIG. 4D is an R_FOR signal. 4E shows the S_FE signal, FIG. 4F shows the output signal of the servo layer focus drive voltage generation circuit 1309, FIG. 4G shows the S_FON signal, and FIG. 4H shows the R_FOD signal.

  Note that the polarity of the output voltage (b) of the recording layer focus drive voltage generation circuit 1305 is assumed to be such that the objective lens 1211 approaches the optical disc 101 when the output voltage is changed in the positive direction. Further, the polarity of the output voltage (f) of the servo layer focus drive voltage generation circuit 1309 can be expressed by whether or not the focus of the laser beam having a wavelength of 650 nm irradiated on the servo layer approaches the optical disc 101. This is because by driving the relay lens 1221 as described above, the focal position of the laser light irradiated to the servo layer changes in a direction perpendicular to the disk surface. The polarity of the output voltage (f) of the servo layer focus drive voltage generation circuit 1309 according to the present embodiment is such that the focus of the laser light applied to the servo layer is the optical disc 101 when the output voltage is changed in the positive direction. It is assumed that the polarity approaches

  When receiving the objective lens sweep instruction, the recording layer focus drive voltage generation circuit 1305 increases the output voltage with time as shown in the period from time t1 to time t3 of the waveform in FIG. As a result, the objective lens 1211 moves closer to the optical disc 101. This operation will be referred to as an objective lens sweep in this specification.

  During the objective lens sweep, an S-shaped waveform is output to the R_FE signal at the timing when the focal point of the laser beam having a wavelength of 405 nm passes through the recording layer of the optical disc 101. For example, time t2 is the timing when the focal point of the laser beam having a wavelength of 405 nm passes through the L3 layer of the optical disc 101.

  FIG. 4 shows a case where the target for drawing in the recording layer is the L0 layer. Time t3 is the timing at which the focal point of the laser beam having a wavelength of 405 nm passes through the L0 layer of the optical disc 101. In this embodiment, this timing is the recording layer focus pull-in timing. As can be seen from FIG. 4, the recording layer focus pull-in timing can be determined by monitoring the R_FE signal, counting the number of S-characters, and detecting the fourth S-character zero-cross point. The system control circuit 1301 performs the S-shaped count and zero-cross point detection described here.

  When detecting that the recording layer focus pull-in timing is reached at time t3, the system control circuit 1301 changes the R_FON signal from the Low level to the High level and outputs it as shown in FIG. When the R_FON signal changes to High level, the switch 1303 is switched, and the output of the recording layer focus control circuit 1302 is supplied to the actuator drive circuit 108. That is, the recording layer focus control is started (turned on), and focus pull-in is performed on the recording layer.

  Further, the system control circuit 1301 issues an instruction to the recording layer focus drive voltage generation circuit 1305 at time t3 to instruct to stop the objective lens sweep. In this embodiment, the recording layer focus drive voltage generation circuit 1305 operates to hold the output voltage value at the time t3 even after receiving an instruction to stop the objective lens sweep at the time t3.

  In FIG. 4, there is a time difference between time t3 and time t4. This is because, in practice, a pull-in check process for checking whether the focus is correctly pulled in is generally performed after the focus pull-in instruction at time t3. However, since the flowchart becomes complicated if a total of two focus pull-in instructions including the behavior at the time of pull-in failure are described, the pull-in check process is omitted in the flowchart of FIG.

  When receiving the relay lens sweep instruction, the servo layer focus drive voltage generation circuit 1309 of the present embodiment increases the output voltage with time as shown in the period from the time t4 to the time t5 of the waveform in FIG. As a result, the focal point of the laser light applied to the servo layer is brought closer to the optical disc 101. This operation is referred to as a relay lens sweep in this specification. Note that the potential after time t5 is expressed as FoOn_L0.

  During the relay lens sweep, an S-shaped waveform is output to the S_FE signal at the timing when the focal point of the laser beam having a wavelength of 650 nm passes through the servo layer of the optical disc 101.

  Time t5 is the timing when the focus of the laser beam having a wavelength of 650 nm passes through the servo layer of the optical disc 101, and this timing is the servo layer focus pull-in timing. As can be seen from FIG. 4, the servo layer focus pull-in timing can be determined by detecting the S-shaped zero cross point of the S_FE signal (e). This zero cross point is detected by the system control circuit 1301.

  When the system control circuit 1301 detects that it is the servo layer focus pull-in timing at time t5, the system control circuit 1301 changes the S_FON signal from the Low level to the High level and outputs it as shown in FIG. When the S_FON signal changes to the high level, the switch 1307 is switched, and the output of the servo layer focus control circuit 1306 is supplied to the relay lens drive circuit 109. That is, servo layer focus control is started (turned on), and focus pull-in to the servo layer is performed.

  Further, the system control circuit 1301 issues an instruction to the servo layer focus drive voltage generation circuit 1309 at time t5 to instruct to stop the relay lens sweep. In this embodiment, the servo layer focus drive voltage generation circuit 1309 operates to hold the output voltage value at the time t5 even after receiving the relay lens sweep stop instruction at the time t5.

  With the operation described above, focus pull-in is performed on each of the recording layer L0 layer and the servo layer.

  Next, the effect of the present embodiment will be described. The optical disc apparatus of the present embodiment has two focus control systems. Among these, the control target of the recording layer focus control system is the actuator 1212. This actuator 1212 exists at a position where both a laser with a wavelength of 405 nm focused on the recording layer and a laser with a wavelength of 650 nm focused on the servo layer pass. On the other hand, the control target of the servo layer focus control system is the relay lens 1221. The relay lens 1221 exists at a position where a laser beam with a wavelength of 650 nm focused on the servo layer passes, but exists at a position where a laser beam with a wavelength of 405 nm focused on the recording layer does not pass.

  In order to realize an optical disc apparatus corresponding to an optical disc having a servo layer and a recording layer, it is necessary to consider this optical positional relationship and perform control suitable for it. The following three points can be given as features of the focus pull-in process in the present embodiment.

  The first point is that the focus pull-in to the servo layer (step S307 in FIG. 3) is started after the timing at which the focus pull-in to the recording layer (step S304 in FIG. 3) is performed. The second point is that not only the objective lens sweep for the recording layer but also the relay lens sweep for the servo layer is performed. The third point is that after pulling in the focus of both the recording layer and the servo layer, track pull-in to the servo layer (step S304 in FIG. 2) is performed.

  First, the effect of performing focus pull-in to the servo layer (step S307 in FIG. 3) after performing focus pull-in to the recording layer (step S304 in FIG. 3), which is the first feature, will be described. Due to the above-described optical positional relationship, the present inventor has found that it is necessary to pay attention to the following points in order to realize an optical disc apparatus corresponding to an optical disc having a servo layer and a recording layer. That is, when the recording layer focus control system drives the actuator 1212, the servo layer focus control system is also affected. On the other hand, even if the servo layer focus control system drives the relay lens 1221, the recording layer focus control system is not affected. This can be understood that the recording layer focus control system and the servo layer focus control system are not completely independent, and the servo layer focus control system is subordinate to the recording layer focus control system.

  Here, the advantage of performing the focus pull-in to the servo layer after the focus pull-in to the recording layer, which is the first feature of the present embodiment, will be described. Consider a case in which the focus pull-in to the recording layer is performed after the focus pull-in to the servo layer in the reverse order to the present embodiment. In that case, after the focus is pulled into the servo layer, the actuator 1212 is swept, and the S-shaped R_FE signal is monitored, and the focus is pulled into the recording layer. At this time, since the actuator 1212 is driven, the servo layer focus control system in which the pull-in is completed is affected. Therefore, depending on the performance of the relay lens 1221 (response speed, movable range, etc.), servo layer focus control that has been pulled in may be lost. According to the focus pull-in process of the present embodiment, first the focus is pulled in with respect to the recording layer focus control system, and then the focus is drawn in with respect to the subordinate servo layer focus control system.

  Further, in this embodiment, the recording layer focus drive voltage generation circuit 1305 and the servo layer focus drive voltage generation circuit 1309 are provided, and the sweep operation is performed for both the recording layer focus control system and the servo layer focus control system. Then, after the focus is drawn in with respect to the recording layer focus control system, the timing of each sweep operation of the recording layer focus control system and the servo layer focus control system is controlled so that the focus is drawn in with respect to the subordinate servo layer focus control system. To pull the focus.

  With this operation, the focus control for controlling the two focus control systems without being affected by the dependency of the two focus control systems of the recording layer focus control system and the servo layer focus control system on the quick and stable focus pull-in. Can be realized. Further, since the focus can be pulled in stably even when the performance (response speed, movable range, etc.) of the relay lens 1221 is low, there is an advantage that the cost can be easily reduced.

  Next, the effect of performing not only the objective lens sweep relating to the recording layer but also the relay lens sweep relating to the servo layer, which is the second feature, will be described. The relay lens 1221 in this embodiment is a lens that can be driven in addition to the actuator. Even in the conventional optical disk apparatus, there are lenses (or elements) that can be driven other than the actuator. This is an aberration correction element (reference numeral 1209 in the configuration of the present embodiment) that also exists in the configuration diagram of the present embodiment. In the focus pull-in operation of the conventional optical disc apparatus, as shown in step S203 of this embodiment, the aberration correction element has only to be driven in advance so as to have a predetermined aberration correction amount. However, in the focus pull-in operation of the optical disk apparatus of the present embodiment, there is a problem only by driving the relay lens 1221 in advance, like the aberration correction element in the conventional optical disk apparatus. Hereinafter, the above problem will be described.

  The relay lens 1221 in the optical disc apparatus of this embodiment functions to correct a difference in distance between the focal point of the laser beam irradiated on the recording layer and the focal point of the laser beam irradiated on the servo layer. In FIG. 4F, the output potential of the servo layer focus drive voltage generation circuit 1309 after time t5 is expressed as FoOn_L0. This value indicates the focus of the laser beam with a wavelength of 405 nm irradiated on the recording layer and the laser beam with a wavelength of 650 nm irradiated on the servo layer in a state where focus control is started on both the recording layer and the servo layer. This is the difference in focal length. That is, FoOn_L0 is a value depending on the distance between the L0 layer and the servo layer. This is because the aberration correction element in the conventional optical disk apparatus corrects the aberration of the laser spot irradiated to the focus pull-in layer, and the amount to be corrected depends on the distance from the disk surface to the focus pull-in layer. Similar.

  In general, when calculating the distance by which the focal point of the laser beam with a wavelength of 650 nm actually irradiated to the servo layer moves from the potential FoOn_L0 output from the servo layer focus drive voltage generation circuit 1309, a predetermined conversion coefficient is used. It can be calculated. However, the sensitivity of the relay lens 1221 is related to the conversion coefficient. The sensitivity of the relay lens 1221 is characterized by large variations.

  When the FoOn_L0 to be driven in advance is calculated from the distance between the L0 layer and the servo layer by calculation, it is deviated from the potential to be actually output due to the sensitivity variation of the relay lens 1221. Therefore, there is a problem in performing the focus pull-in process by driving the relay lens 1221 in advance and performing the sweep operation of only the objective lens. The reason why the spherical aberration correction element in the conventional optical disk apparatus had to be driven in advance so as to obtain a predetermined aberration correction amount is that the potential applied to the spherical aberration correction element and the aberration correction amount by the spherical aberration correction element This is because there is little variation in the conversion coefficient. For the reasons described above, the present inventor needs to sweep the relay lens 1221 as described in the present embodiment in order to realize the focus pull-in of the optical disc apparatus corresponding to the optical disc having the servo layer and the recording layer. Found.

  As in the present embodiment, not only the objective lens sweep related to the recording layer but also the relay lens sweep related to the servo layer is performed, so that it is possible to prevent a focus pull-in failure due to the sensitivity variation of the relay lens 1221. As a result, it becomes possible to perform focus pull-in stably with respect to the servo layer.

  Next, the effect of performing track pull-in to the servo layer after performing focus pull-in of both the recording layer and the servo layer, which is the third feature of the present embodiment, will be described.

  In a conventional DVD or BD compatible optical disc apparatus, there is only one focus control system. In the conventional optical disc apparatus, since the tracking error signal is output if the focus pull-in is completed, the track pull-in is performed following the focus pull-in.

  However, for an optical disk such as a grooveless disk, in particular, in the case where the optical disk 101 is an optical disk on which no information is recorded, since there is no track in the recording layer, there is no readable address. There is no need to pull the track against. The inventor has found that since an address to be referred to by the optical disk apparatus is read from the servo layer, it is preferable to draw a track into the servo layer.

  In other words, the focus pull-in is performed first from the recording layer focus control system according to the feature of the first point, and then the track pull-in is not performed for the recording layer, and the focus pull-in is also performed for the servo layer focus control system. Then, the track pull-in operation is performed on the servo layer. As a result, the setup process can be performed without performing unnecessary track pull-in.

  In the setup process, a seek operation for driving the optical pickup 102 in the radial direction is performed. In order to perform a seek operation, it is necessary to read address information from the optical disc 101. In the setup process, the track is first drawn into the servo layer, so that the address can be reliably read even when no information is recorded on the optical disc 101. Therefore, it is possible to make a state in which a seek operation or the like is possible at an early stage.

  As described above, the setup time can be shortened by performing the track pull-in to the servo layer after the focus pull-in of both the recording layer and the servo layer.

  Here, a difference from the optical disc apparatus disclosed in Patent Document 2 will be described. If the description of Patent Document 2 is cited, the focus adjustment liquid crystal panel LCP that focuses the servo laser beam RB and the recording laser beam RB by the objective lens OB at different positions in the film thickness direction is provided. Further, the lens actuator 36 that drives the objective lens OB in the focus and tracking directions is driven by an error signal obtained by calculation based on the output of the servo photodetector SPD by positioning servo control of the control device 101. Further, the control device separates the position of the composite focal point FP of the focus adjustment liquid crystal panel LCP and the objective lens OB by an integral multiple of the distance between the two adjacent layers of the recording layer 5 in the film thickness direction of the recording layer group 50 of the medium. To set.

  From the above description, the focus control for driving the objective lens OB in the configuration of Patent Document 2 is performed on the servo layer. Then, the control device drives the focus adjustment liquid crystal panel LCP to correct a difference in distance between the focal point of the laser beam irradiated on the servo layer and the focal point of the laser beam irradiated on the recording layer.

  Therefore, there is no circuit corresponding to the recording layer focus control circuit 1302 in this embodiment. In other words, the control system that drives the focus adjustment liquid crystal panel LCP is not a feedback control system that performs control based on an error signal, but a feedforward control system. Since the focus control is not performed on the recording layer, the recording performance and the playback performance are problematic. In this embodiment, since the focus control is performed also on the recording layer, it is possible to ensure good recording performance and reproduction performance.

  Further, in Patent Document 2, focus pull-in is not directly mentioned, but it is appropriate to sweep the objective lens OB to perform focus pull-in. The focus adjustment liquid crystal panel LCP in Patent Document 2 exists at a position where both the laser focused on the recording layer and the laser focused on the servo layer pass. Therefore, when the focus is pulled in, the focus adjustment liquid crystal panel LCP that corrects the difference in the distance between the focal point of the laser beam applied to the servo layer and the focal point of the laser beam applied to the recording layer is the difference between the predetermined distances. The operation is to be driven in advance so that

  Therefore, in Patent Document 2, there is no focus pull-in operation itself for the recording layer, and therefore there is no need to consider the order of focus pull-in to the recording layer and focus pull-in to the servo layer, which is the first feature of this embodiment. It is. Furthermore, since the control system for driving the focus adjustment liquid crystal panel LCP is a feedforward control system, it is not necessary to consider the two sweep operations that are the second feature in this embodiment. The reason why the sweep operation is performed in the present embodiment is that the S-shaped waveform of the focus error signal is output by the sweep operation, the zero cross point of the focus error is detected, and feedback control is started.

  The above points are the difference between the present embodiment and the optical disc apparatus disclosed in Patent Document 2. In the objective lens sweep operation, the waveform output from the recording layer focus drive voltage generation circuit 1305 is a voltage pattern that increases with time as shown by the period from time t1 to time t3 of the waveform in FIG. This is not a limitation. In the above description, the objective lens 1211 is always driven in the direction approaching the optical disc 101, and the focus is drawn into the recording layer during the driving. For example, after driving in a direction approaching the optical disc 101, driving in a direction away from the optical disc 101, and driving in a direction away from the optical disc 101, the focus may be drawn into the recording layer. Similarly, the waveform output from the servo layer focus drive voltage generation circuit 1309 in the relay lens sweep operation is not limited to the waveform shown in FIG.

  In this embodiment, the focus pull-in process in the setup process has been described as shown in FIG. 2, but the present invention can be similarly applied to a focus pull-in process other than the setup process. As an example, for example, there is focus pull-in when returning from the standby state. The standby state refers to a state in which the optical disc apparatus is stopped when there is no request from the host for a certain period of time and the laser light emission, the rotation of the spindle motor 104, and the like are stopped. As another example, there is a focus pull-in at the time of return when the focus control is lost for some reason after the focus pull-in. With respect to any focus pull-in, focus pull-in to the recording layer and the servo layer is possible by using the same procedure as the focus pull-in process shown in FIG.

  In the above description, the relay lens sweep is started after the focus is pulled into the recording layer (step S306 is executed after step S304). However, the relay lens sweep may be started before the focus is pulled into the recording layer. In this case, the waveform diagram is as shown in FIG. 5, for example. In FIG. 5, the relay lens sweep is started at time t4 before the focus is pulled into the recording layer at time t3. Even if the servo layer focus control system drives the relay lens 1221, the recording layer focus control system is not affected, and thus the above operation is possible. By applying the above operation, the time required for the focus pull-in process can be shortened.

  Considering further reduction in time, the start timing of the relay lens sweep shown at time t4 is set until the focus drawing timing of the recording layer shown at time t3 matches the focus drawing timing of the servo layer shown at time t5. It is possible to shift. That is, it is possible to shift the start timing of the relay lens sweep forward within a range that does not cause a situation in which the objective lens sweep is continuously performed after the focus pull-in timing of the servo layer. As described above, if the objective lens sweep is continuously performed after the focus pull-in timing of the servo layer, the actuator driving affects the servo layer focus control system in which the pull-in is completed. This is because depending on the performance (response speed, movable range, etc.) of the relay lens, there is a problem that the servo layer focus control in which the pull-in is completed is lost. In the case of FIG. 5 as well, there is a relationship that the focus pull-in timing (time t3) for the recording layer is before or substantially the same as the focus pull-in timing (time t5) for the servo layer.

  A supplementary description will be given of a case where the focus pull-in timing (time t3) for the recording layer is substantially the same as the focus pull-in timing (time t5) for the servo layer. In this case, the start timing time t4 of the relay lens sweep is calculated including the sensitivity variation of the relay lens 1221 described above. This variation in sensitivity has become a problem when the focus pull-in process is performed by driving the relay lens 1221 in advance and only the objective lens is swept, but does not become a problem when the relay lens sweep is performed. . This is because the relay lens is actually driven by vibration. When the relay lens is driven to vibrate, the focus of the laser beam having a wavelength of 650 nm irradiated on the servo layer also moves while vibrating in a direction perpendicular to the disk surface. Therefore, even when the sensitivity of the relay lens 1221 varies, the focal point of the laser beam having a wavelength of 650 nm passes through the servo layer. As a result, the focus pull-in can be performed by detecting the S-shaped zero cross point of the S_FE signal with respect to the servo layer.

  By the above operation, the optical disc apparatus of Embodiment 1 can realize focus control and tracking control suitable for an optical disc having a servo layer and a recording layer.

  This embodiment is an embodiment for realizing a focus jump operation for an optical disc having a servo layer and a recording layer. The configuration of the optical disk apparatus of the present embodiment is the same as that of FIG.

  Hereinafter, the operation of the system control circuit 1301 in this embodiment will be described with reference to the flowchart of the focus jump process shown in FIG. When the focus jump process is started (step S601), the system control circuit 1301 changes the TON signal from the high level to the low level to instruct the stop of the tracking control (step S602). As a result, the switch 1311 is switched and the tracking control is turned off. Next, the system control circuit 1301 changes the S_FON signal from High level to Low level to instruct to stop servo layer focus control (step S603). As a result, the switch 1307 is switched and the servo layer focus control is turned off. Next, the system control circuit 1301 changes the R_FON signal from High level to Low level to instruct to stop the recording layer focus control (Step S604). As a result, the switch 1303 is switched and the recording layer focus control is turned off. Next, the system control circuit 1301 instructs the recording layer focus drive voltage generation circuit 1305 to start the first jump voltage output (step S605). By outputting the first jump voltage, the actuator 1212 is accelerated, and the movement of the focal point of the laser beam having a wavelength of 405 nm is started. Next, the system control circuit 1301 monitors the level of the R_FE signal output from the servo error signal generation circuit 105, and determines whether or not the amplitude of the R_FE signal is greater than or equal to a predetermined threshold Th_FJ1 (step S606). Here, since the R_FE signal is a signal based on Vref, the amplitude of the R_FE signal means the absolute value of the voltage difference between the level of the R_FE signal and Vref.

  When the amplitude of the R_FE signal is less than the predetermined threshold Th_FJ1 (No in step S606), the process returns to step S606. On the other hand, when the amplitude of the R_FE signal is equal to or greater than the predetermined threshold Th_FJ1 (Yes in step S606), the system control circuit 1301 monitors the level of the R_FE signal, and the amplitude of the R_FE signal is less than the predetermined threshold Th_FJ1. It is determined whether or not there is (step S607). When the amplitude of the R_FE signal is larger than the predetermined threshold Th_FJ1 (No in step S607), the process returns to step S607. On the other hand, when the amplitude of the R_FE signal is less than the predetermined threshold Th_FJ1 (Yes in step S607), the system control circuit 1301 instructs the recording layer focus drive voltage generation circuit 1305 to start the second jump voltage output. (Step S608). The acceleration of the actuator 1212 is weakened by outputting the second jump voltage.

  Here, the operation from step S606 to step S608 can be rephrased as follows. The system control circuit 1301 monitors the level of the R_FE signal, and instructs the start of the second jump voltage output at a timing when the amplitude of the R_FE signal exceeds a predetermined threshold Th_FJ1 and then falls below the threshold Th_FJ1. Next, the system control circuit 1301 monitors the level of the R_FE signal, and determines whether or not the amplitude of the R_FE signal is greater than or equal to a predetermined threshold Th_FJ2 (step S609). When the amplitude of the R_FE signal is less than the predetermined threshold Th_FJ2 (No in step S609), the process returns to step S609. On the other hand, when the amplitude of the R_FE signal is greater than or equal to the predetermined threshold Th_FJ2 (Yes in step S609), the system control circuit 1301 starts the third jump voltage output to the recording layer focus drive voltage generation circuit 1305. An instruction is given (step S610). The actuator 1212 is decelerated by outputting the third jump voltage.

  Subsequently, the system control circuit 1301 monitors the R_FE signal output from the servo error signal generation circuit 105 and determines whether it is the recording layer focus pull-in timing (step S611). If it is not the recording layer focus pull-in timing (No in step S611), the process returns to S611 and S303 and waits until the recording layer focus pull-in timing is reached. When it is the recording layer focus pull-in timing (Yes in step S611), the system control circuit 1301 instructs the focus pull-in to the recording layer by setting the R_FON signal to high (step S612). Further, the recording layer focus drive voltage generation circuit 1305 is instructed to stop the output of the jump voltage (step S613).

  Subsequently, the system control circuit 1301 instructs the servo layer focus drive voltage generation circuit 1309 to perform a relay lens sweep (step S614). When receiving the relay lens sweep instruction, the servo layer focus drive voltage generation circuit 1309 outputs a voltage having a predetermined pattern to drive the relay lens 1221. Subsequently, the system control circuit 1301 monitors the S_FE signal output from the servo error signal generation circuit 105 and determines whether it is the servo layer focus pull-in timing (step S615).

  If it is not the servo layer focus pull-in timing (No in step S615), the process returns to S615 and waits until the servo layer focus pull-in timing is reached. If it is the servo layer focus pull-in timing (Yes in step S615), the system control circuit 1301 instructs the focus pull-in process to the servo layer by setting the S_FON signal to high (step S616). Further, the servo layer focus drive voltage generation circuit 1309 is instructed to stop the relay lens sweep (step S617). After step S617, the system control circuit 1301 changes the TON signal from the low level to the high level to instruct the start of tracking control (step S618). As a result, the switch 1311 is switched and the tracking control is turned on. Thus, the focus jump process is completed (step S619).

  Next, the operation of each part in the focus jump process of this embodiment will be described with reference to FIG. FIG. 7 is a waveform diagram showing signals at various parts of the focus control system during the focus jump process from the L0 layer to the L1 layer. Among the waveforms shown in FIG. 7, (a) to (d) are signals relating to the recording layer, and (e) to (h) are signals relating to the servo layer. The tracking control system signal is not shown.

  7A shows the R_FE signal, FIG. 7B shows the output signal of the recording layer focus drive voltage generation circuit 1305, FIG. 7C shows the R_FON signal, and FIG. 7D shows the R_FOR signal. 7E shows the S_FE signal, FIG. 7F shows the output signal of the servo layer focus drive voltage generation circuit 1309, FIG. 7G shows the S_FON signal, and FIG. 7H shows the R_FOD signal. The polarity of the output voltage (b) of the recording layer focus drive voltage generation circuit 1305 and the polarity of the output voltage (f) of the servo layer focus drive voltage generation circuit 1309 are the same as those in the first embodiment.

  As an operation of the focus control system in the focus jump process, first, at time t1, the system control circuit 1301 changes the S_FON signal from the High level to the Low level and outputs it as shown in FIG. When the S_FON signal changes to the Low level, the switch 1307 is switched, and the output of the servo layer focus control circuit 1306 is not supplied to the relay lens drive circuit 109. That is, the servo layer focus control is turned off.

  At this time, the switch 1307 is switched and the output of the servo layer focus control circuit 1306 is not supplied to the relay lens drive circuit 109, but the output of the servo layer focus drive voltage generation circuit 1309 is continuously supplied. For this reason, S_FOD does not become the reference potential Vref.

  Subsequently, at time t2, the system control circuit 1301 changes the R_FON signal from the High level to the Low level as shown in FIG. 7C, and turns off the recording layer focus control as described above. At the same time, the system control circuit 1301 issues an instruction to the recording layer focus drive voltage generation circuit 1305 to start outputting the jump voltage. As shown in the period from time t2 to time t5 in FIG. 7B, it is assumed that the jump voltage sequentially outputs three values. At time t1, the first jump voltage V1_FJ is output. Next, the system control circuit 1301 monitors the level of the R_FE signal, and detects a timing when the amplitude of the R_FE signal has exceeded a predetermined threshold Th_FJ1 and then has decreased below the threshold Th_FJ1. Time t3 indicates the detected timing. At time t3, the output voltage (b) of the recording layer focus drive voltage generation circuit 1305 is changed to the second jump voltage V2_FJ. Next, the system control circuit 1301 monitors the level of the R_FE signal and detects a timing at which the amplitude of the R_FE signal exceeds a predetermined threshold Th_FJ2. Time t4 indicates the detected timing. At time t4, the output voltage (b) of the recording layer focus drive voltage generation circuit 1305 is changed to the third jump voltage V3_FJ. The jump waveform as shown in FIG. 7 is output in synchronization with the R_FE signal and output to the actuator drive circuit 108, whereby the objective lens 1211 is driven, and the focus of the laser beam having a wavelength of 405 nm is changed from the L0 layer to the L1 layer. Moved towards. Next, the system control circuit 1301 detects the recording layer focus pull-in timing. Time t5 is the timing when the focus of the laser beam having a wavelength of 405 nm passes through the L1 layer of the optical disc 101. In this embodiment, this timing is the recording layer focus pull-in timing.

  As can be seen from FIG. 7, the recording layer focus pull-in timing can be determined by detecting the zero cross point of the R_FE signal. This zero cross point is detected by the system control circuit 1301. When detecting that the recording layer focus pull-in timing is reached at time t5, the system control circuit 1301 changes the R_FON signal from the Low level to the High level and outputs it as shown in FIG. 7C. When the R_FON signal changes to High level, the switch 1303 is switched, and the output of the recording layer focus control circuit 1302 is supplied to the actuator drive circuit 108. That is, the recording layer focus control is turned on, and the focus pull-in to the recording layer is performed. Further, the system control circuit 1301 issues an instruction to the recording layer focus drive voltage generation circuit 1305 at time t5 to instruct the output stop of the jump voltage. With this operation, the focus jump from the L0 layer to the L1 layer is completed with respect to the recording layer focus control system.

  Further, FIG. 7 shows that there is a time difference between time t5 and time t6. This is because, in practice, a pull-in check process for checking whether the focus is correctly pulled in is generally performed after the focus pull-in instruction at time t5. However, if a total of two focus pull-in instructions including the behavior at the time of pull-in failure is described, the flowchart becomes complicated, and therefore the pull-in check process is omitted in the flowchart of FIG.

  When receiving the relay lens sweep instruction in the focus jump from the L0 layer to the L1 layer, the servo layer focus drive voltage generation circuit 1309 of the present embodiment, as shown in the period from time t6 to time t7 of the waveform in FIG. Increase the output voltage with time. As a result, the focal point of the laser light applied to the servo layer is brought closer to the optical disc 101. This operation is referred to as a relay lens sweep in this specification. Note that a potential before time t6 is expressed as FoOn_L0, and a potential after time t7 is expressed as FoOn_L1.

  During the relay lens sweep, an S-shaped waveform is output to the S_FE signal at the timing when the focal point of the laser beam having a wavelength of 650 nm passes through the servo layer of the optical disc 101. Time t7 is the timing at which the focus of the laser beam having a wavelength of 650 nm passes through the servo layer of the optical disc 101, and this timing is the servo layer focus pull-in timing.

  As can be seen from FIG. 7, the servo layer focus pull-in timing can be determined by detecting the S-shaped zero cross point of the S_FE signal (e). This zero cross point is detected by the system control circuit 1301. When the system control circuit 1301 detects that it is the servo layer focus pull-in timing at time t7, the system control circuit 1301 changes the S_FON signal from the Low level to the High level and outputs it as shown in FIG. When the S_FON signal changes to the high level, the switch 1307 is switched, and the output of the servo layer focus control circuit 1306 is supplied to the relay lens drive circuit 109. That is, the servo layer focus control is turned on, and focus pull-in to the servo layer is performed. Further, the system control circuit 1301 issues an instruction to the servo layer focus drive voltage generation circuit 1309 at time t7 to instruct to stop the relay lens sweep. In the present embodiment, the servo layer focus drive voltage generation circuit 1309 operates to hold the output voltage value at the time t7 even after receiving the relay lens sweep stop instruction at the time t7. With the operation described above, a focus jump operation from the recording layer L0 layer to the L1 layer is performed.

  Although FIG. 7 shows that there is a time difference between the timing at which the servo layer focus control at time t1 is turned off and the timing at which the recording layer focus control at time t2 is turned off, the time difference is eliminated and two focus control systems are used. May be turned off simultaneously.

  Here, FIG. 7 shows a waveform in the case of a focus jump from the L0 layer to the L1 layer, that is, from the side far from the surface of the optical disc 101 toward the surface. On the other hand, the difference in operation of each part at the time of focus jump in the reverse direction will be described with reference to FIG. FIG. 8 is a waveform diagram showing signals of respective parts of the focus control system during the focus jump process from the L1 layer to the L0 layer, contrary to the case of FIG. 8A to 8H indicate the same signals as those in FIG. 7, and the times t1 to t7 in FIG. 8 correspond to the times t1 to t7 in FIG.

  By changing the direction of the focus jump, first, the polarity of the jump voltage output in the period from time t2 to time t5 in the output voltage (b) of the recording layer focus drive voltage generation circuit 1305 is reversed. This is the same as the conventional optical disc apparatus. When receiving the relay lens sweep instruction in the focus jump from the L1 layer to the L0 layer, the servo layer focus drive voltage generation circuit 1309 of the present embodiment, as shown in the period from time t6 to time t7 of the waveform in FIG. Reduce the output voltage over time. As described above, the servo layer focus drive voltage generation circuit 1309 of this embodiment changes the direction in which the relay lens sweep is performed according to the focus jump direction.

  Hereinafter, how to determine the direction of the relay lens sweep after the focus jump will be described. The relay lens 1221 in the optical disc apparatus of this embodiment functions to correct a difference in distance between the focal point of the laser beam irradiated on the recording layer and the focal point of the laser beam irradiated on the servo layer.

  Here, in the focus jump process from the L0 layer to the L1 layer shown in FIG. 7, the output value (f) of the servo layer focus drive voltage generation circuit 1309 before the focus jump is denoted as TgtV_L0. On the other hand, the output value (f) of the servo layer focus drive voltage generation circuit 1309 after the focus jump in the focus jump process from the L1 layer to the L0 layer shown in FIG. 8 is also shown as TgtV_L0. In any case, TgtV_L0 becomes a value depending on the distance between the L0 layer and the servo layer, and TgtV_L0 in FIG. 7 and TgtV_L0 in FIG. 8 have the same value. The same applies to TgtV_L1.

  From this, the present inventor has clarified that the direction in which the relay lens sweep is performed by driving the servo layer focus drive voltage generation circuit 1309 after the focus jump is uniquely determined. Therefore, if the direction in which the relay lens 1221 is driven is determined according to the focus jump direction, the focus can be surely drawn into the servo layer. As a result of this operation, for example, in the case of a focus jump from the L0 layer to the L1 layer and in the case of a focus jump from the L1 layer to the L0 layer, the relay lens sweep direction is reversed.

  Next, the effect of the present embodiment will be described. As described in the first embodiment, the present inventor has found that it is necessary to pay attention to the following points in order to realize an optical disc apparatus corresponding to an optical disc having a servo layer and a recording layer. That is, when the recording layer focus control system drives the actuator 1212, the servo layer focus control system is also affected. On the other hand, even if the servo layer focus control system drives the relay lens 1221, the recording layer focus control system is not affected. This can be understood that the recording layer focus control system and the servo layer focus control system are not completely independent, and the servo layer focus control system is subordinate to the recording layer focus control system.

  In a conventional DVD or BD compatible optical disc apparatus, there is only one focus control system. In the conventional optical disc apparatus, only the focus control system which is a control system for performing the focus jump is considered, and the jump jump is performed by applying the jump voltage. However, when performing a focus jump between recording layers in an optical disc apparatus corresponding to an optical disc having a servo layer and a plurality of recording layers, there is a problem in performing the conventional focus jump processing as it is.

  Thus, a problem in performing a focus jump between recording layers in an optical disc apparatus corresponding to an optical disc having a servo layer and a plurality of recording layers will be described. If the conventional focus jump process is applied as it is, only the recording layer focus control system is considered, and a jump voltage is output from the recording layer focus drive voltage generation circuit 1305 to perform the focus jump. In this case, the servo layer focus control system is also affected. That is, by moving the focal point of the laser beam irradiated to the recording layer from the L1 layer to the L0 layer, the focal point of the laser beam irradiated to the servo layer is also on the disk surface by the distance between the L0 layer and the L1 layer. It moves in the vertical direction. This means that depending on the performance of the relay lens 1221 (response speed, movable range, etc.), the servo layer focus control in which the pull-in is complete may be lost.

  Therefore, in this embodiment, the servo layer focus control is turned off before the focus jump, and then the jump voltage is applied to the recording layer focus control system to execute the focus jump. After the recording layer focus control is turned on, the servo layer is turned on. Focus retraction is performed.

  Further, the conventional optical disc apparatus has only one focus control system. For this reason, if a focus jump is performed and the focus recording is performed on the recording layer to which the jump has been performed, the operation related to the focus control system has been completed.

  However, the optical disk apparatus of the present embodiment has two focus control systems. In this case, the focus control system (recording layer focus control system) that performs the focus jump and the focus control system (servo layer focus control system) that does not perform the focus jump are classified. In particular, the operation before and after the focus jump related to the focus control system that does not perform the focus jump has not been clarified so far.

  As described above, the present inventor has clarified that the direction in which the relay lens sweep is performed by driving the servo layer focus drive voltage generation circuit 1309 after the focus jump is determined. Therefore, in this embodiment, the direction in which the relay lens is driven is determined according to the focus jump direction, so that the focus can be surely drawn into the servo layer.

  Further, in this embodiment, when the switch 1307 is switched to turn off the servo layer focus control, the output of the servo layer focus drive voltage generation circuit 1309 is continuously supplied to the relay lens drive circuit 109. If all the outputs related to the servo layer focus control are stopped, the output of the servo layer focus drive voltage generation circuit 1309 falls to the reference potential Vref, and the distance driven by the relay lens sweep becomes longer. For this reason, the time required for the focus jump process increases. According to this embodiment, the time required for the focus jump process can be shortened.

  In the above description, the relay lens sweep is started after the focus is pulled into the recording layer (the step S614 is performed after the step S612). However, the relay lens sweep may be started before the focus is pulled into the recording layer.

  In this case, the waveform diagram is as shown in FIG. 9, for example. In FIG. 9, the relay lens sweep is started at time t6 before the focus is pulled into the recording layer at time t5. Even if the servo layer focus control system drives the relay lens 1221, the recording layer focus control system is not affected, and thus the above operation is possible. By applying the above operation, the time required for the focus jump process can be shortened. Considering further reduction in time, the start timing of the relay lens sweep shown at time t6 is set until the focus drawing timing of the recording layer shown at time t5 matches the focus drawing timing of the servo layer shown at time t7. It is possible to shift. In the case of FIG. 9 as well, the relationship that the focus pull-in timing (time t5) for the recording layer is before or substantially the same as the focus pull-in timing (time t7) for the servo layer is established.

  Finally, the operation of the aberration correction element 1209 in this embodiment will be described. The operation of the aberration element 1209 in the focus jump method of this embodiment is omitted in the above description. This is because the present invention focuses on the configuration of the optical disc apparatus having two focus control systems, and particularly focuses on the operations before and after the focus jump related to the focus control system that does not perform the focus jump. Therefore, also in FIG. 7 which is a waveform diagram of this embodiment, the drive signal includes the output signal of the recording layer focus drive voltage generation circuit 1305 for driving the jump voltage and the servo layer focus drive for performing the characteristic operation in the present invention. The description has been given focusing on two of the output signals of the voltage generation circuit 1309. As a focus jump method in the recording layer focus control system, which is a focus control system for performing a focus jump out of the two focus control systems, a focus jump method devised in a conventional optical disc apparatus may be used.

  As a driving method of the aberration correction element in the focus jump devised in the conventional optical disc apparatus, as exemplified in Patent Document 3 and Patent Document 4, several driving methods are disclosed. These will be described with reference to FIG. FIGS. 17A and 17B are a focus error signal and a focus drive signal of the focus control system for performing the focus jump, and are the same as FIGS. 7A and 7B in this embodiment. Also, times t2, t3, t4, and t5 are the same as those in FIG. FIGS. 17C-1 to 17C-4 are drive signals for driving the aberration drive element 1209, and are signals indicating aberration correction amounts. As shown in FIG. 17 (c-1), the driving method of Patent Document 3 is a method of driving the aberration elements by 50% of the whole before the focus jump and driving the remaining 50% after the focus jump. Further, as a modified example in Patent Document 3, as shown in FIG. 17C-2, a method of driving 100% of the entire aberration element before the focus jump, as shown in FIG. As shown in 3), after the focus jump, 100% of the entire aberration element is driven. Furthermore, as shown in FIG. 17 (c-4), the driving method of Patent Document 4 is a method of gradually driving the aberration correction element during a period from time t2 to time t5 when the focus jump voltage is applied. .

  In FIG. 6 which is a flowchart of the present embodiment, FIG. 7 which is a waveform diagram, etc., the description regarding the aberration correction element 1209 is omitted, but there are several patterns in the driving method of the aberration correction element in the prior art. Any pattern can be applied to the present embodiment. Further, in the following examples regarding the focus jump, the description regarding the aberration correction element 1209 is omitted as in the present example.

  By the above operation, the optical disc apparatus of Embodiment 2 can realize focus control and tracking control suitable for an optical disc having a servo layer and a recording layer.

  This embodiment is an embodiment for realizing a focus jump operation for an optical disc having a servo layer and a recording layer. In the second embodiment, the servo layer focus control is always turned off in the focus jump process. This embodiment corresponds to a modification of the second embodiment. The configuration of the optical disk apparatus of the present embodiment is the same as that of FIG.

  Hereinafter, the operation of the system control circuit 1301 in the present embodiment will be described using the flowchart of the focus jump process shown in FIG. In addition, the same number is attached | subjected about the same step as FIG. 6 which is the flowchart of Example 2, and description is abbreviate | omitted.

  When the focus jump process is started (step S601), the system control circuit 1301 instructs to stop tracking control (step S602). Subsequently, the system control circuit 1301 determines whether the number of layers for focus jump is equal to or greater than a predetermined threshold N_FJ (step S620). If the number of focus jump layers is equal to or greater than the predetermined threshold N_FJ (Yes in step S620), stop of servo layer focus control is instructed in the same manner as in the second embodiment (step S603), and then step S604 is performed. move on.

  On the other hand, when the number of focus jump layers is smaller than the predetermined threshold N_FJ (No in step S620), the system control circuit 1301 issues an instruction to the servo layer focus control circuit 1306 and is set in the servo layer focus control circuit 1306. The characteristic is changed (step S621). After step S621, the process proceeds to step S604.

  In step S621 in this embodiment, it is assumed that the gain of the characteristic set in the servo layer focus control circuit 1306 is uniformly changed to a characteristic lowered by 3 dB.

  Thereafter, steps S604 to S613 are the application of the focus jump voltage and the focus pull-in operation to the recording layer, and are the same as in the second embodiment.

  After step S613, the system control circuit 1301 again determines whether or not the number of layers for focus jump is equal to or greater than a predetermined threshold N_FJ (step S622). If the number of focus jump layers is equal to or greater than the predetermined threshold value N_FJ (Yes in step S622), the steps from step S614 to step S617 are sequentially performed as in the second embodiment, and the process proceeds to step S618. The operation from step S614 to step S617 is an operation of driving the relay lens 1221 and issuing a servo layer focus pull-in instruction and a relay lens sweep stop instruction in synchronization with the servo layer focus pull-in timing.

  On the other hand, if the number of layers for focus jump is smaller than the predetermined threshold N_FJ (No in step S622), the system control circuit 1301 issues an instruction to the servo layer focus control circuit 1306 and is set in the servo layer focus control circuit 1306. The characteristic is changed (step S6223). After step S623, the process proceeds to step S618.

  In step S623 in this embodiment, the gain of the characteristic set in the servo layer focus control circuit 1306 is uniformly changed to a characteristic increased by 3 dB, and the characteristic before the execution of step S621 is returned. Thereafter, in step S618, the start of tracking control is instructed, and then the focus jump process ends (step S619).

  Next, the effect of the present embodiment will be described. The focus jump process in the present embodiment is the same as the focus jump process in the second embodiment when the number of layers for focus jump is equal to or greater than a predetermined threshold N_FJ. When the number of layers for focus jump is smaller than the predetermined threshold value N_FJ, the servo layer focus control is not turned off in this embodiment. That is, in the focus jump process, the servo layer focus control system is kept on.

  As a result, the relay lens sweep need not be performed, and thus the steps from step S614 to step S617 are omitted as shown in FIG. For this reason, the time required for the focus jump can be shortened by the time required for the relay lens sweep.

  In the present embodiment, the above processing is performed only when the number of layers for focus jumping is smaller than a predetermined threshold N_FJ. There are two reasons for this. For one thing, when the distance between the focus jump layers exceeds the movable range of the relay lens 1221, the relay lens 1221 hits the movable end during the jump, and the servo layer focus control system is turned on as described above. This is because the focus jump of the recording layer cannot be performed.

  In addition, when the distance between the focus jump layers exceeds the distance of the S-shaped negative feedback region of the focus error signal SFE of the servo layer, the focal position of the laser irradiated to the servo layer during the jump Exceeds the S-shaped negative feedback region. For this reason, the servo layer focus control system becomes uncontrollable, and even in this case, the focus jump of the recording layer cannot be performed with the servo layer focus control system turned on.

  Here, the S-shaped negative feedback region will be described with reference to FIG. FIG. 16 is a schematic diagram of the SFE signal when the focal point of the laser irradiated to the servo layer crosses the vicinity of the servo layer at a constant speed. The horizontal axis represents the focal position of the laser irradiated on the servo layer. X0 is the position when the focus of the laser is applied to the servo layer, and X1 and X2 are positions corresponding to the vertices of the S-shape, respectively. As shown in FIG. 16, in this specification, the region from X1 to X2 is referred to as a negative feedback region. Further, the distance from X1 to X2 is called the distance of the negative feedback region.

  As described above, in order to perform the operation of the present embodiment with respect to the focus jump of the optical disc apparatus having two focus control systems, the distance between the layers for the focus jump is smaller than the movable range of the relay lens 1221 and the SFE signal. It is necessary to be smaller than the distance of the S-shaped negative feedback region. Therefore, the predetermined threshold value N_FJ needs to be determined so as to satisfy this condition. This is because if either one is not satisfied, the servo layer focus control system cannot continue to follow the servo layer during focus jump. On the other hand, when the distance between the focus jumping layers is smaller than the movable range of the relay lens 1221 and smaller than the distance of the S-shaped negative feedback area of the SFE signal, the focus jumping with respect to the recording layer is performed with the servo layer focus control system turned on. The operation | movement which performs is possible.

  Further, when the distance between the movable range of the relay lens 1221 and the S-shaped negative feedback area of the SFE signal is sufficiently large with respect to the interlayer distance of the recording layer, the focus jump always satisfies the above condition. It is obvious that the operation of performing the focus jump on the recording layer may be performed while the servo layer focus control system is turned on regardless of the number of layers to be performed.

  Further, in this embodiment, when a focus jump is performed on the recording layer while the servo layer focus control system is turned on, an operation for changing characteristics set in the servo layer focus control circuit 1306 is performed in steps S621 and S623. In this embodiment, during the period from step S604 to step S613, that is, the period during which the focus jump voltage is applied and the focus pull-in operation to the recording layer is executed, the characteristic set in the servo layer focus control circuit 1306 has a uniform gain of 3 dB. It becomes a lowered characteristic. This effect will be described.

  As described in the second embodiment, when only the recording layer focus control system is considered and a jump voltage is output from the recording layer focus drive voltage generation circuit 1305 and the focus jump is performed, the servo layer focus control system is also affected. . In other words, the influence of the jump voltage is added as a disturbance of the servo layer focus control system.

  One of the factors of whether or not servo control is lost when a disturbance is applied to the servo system is the magnitude of the disturbance. In the focus jump in the optical disc apparatus corresponding to the optical disc having the servo layer and the recording layer, the servo system is the servo layer focus control system, and the magnitude of the disturbance corresponds to the distance between the layers moved by the focus jump. To do.

  That is, when the distance between the layers moved by the focus jump is small, the servo layer focus control is not removed even if the focus jump of the recording layer is performed. On the other hand, when the distance between the layers moved by the focus jump is large, the servo layer focus control is lost when the focus jump of the recording layer is performed. The present embodiment is an embodiment focusing on this point.

  Furthermore, the servo system response is another factor that determines whether the servo system is out of control when a disturbance is applied to the servo system. If the response of the servo system is sensitive, the servo system reacts greatly to disturbances, and the servo failure may be induced by the response of the servo system.

  In the present embodiment, during the period from step S604 to step S613, the characteristic set in the servo layer focus control circuit 1306 is a characteristic in which the gain is uniformly reduced by 3 dB. This is to reduce the response of the servo system by reducing the response of the servo system and reducing the response caused by the disturbance applied to the servo layer focus control system during the focus jump, as described above.

  However, if the characteristic originally set in the servo layer focus control circuit 1306 is a characteristic that does not respond very much to the disturbance during the focus jump, it is obvious that the characteristic of the servo layer focus control circuit 1306 need not be changed. It is.

  With the above operation, the optical disc apparatus of Embodiment 3 can realize focus control and tracking control suitable for an optical disc having a servo layer and a recording layer.

  This embodiment is an embodiment for realizing a focus jump operation for an optical disc having a servo layer and a recording layer. The configuration of the optical disk apparatus of the present embodiment is the same as that of FIG.

  Hereinafter, the operation of the system control circuit 1301 in this embodiment will be described with reference to the flowchart of the focus jump process shown in FIG. In addition, the same number is attached | subjected about the same step as FIG. 6 which is the flowchart of Example 2, and description is abbreviate | omitted.

  The difference between the present embodiment and the second embodiment is that a portion related to an output start instruction for each jump voltage in steps S624, S625, and S626, a portion related to an output stop instruction for a jump voltage in step S627, and a servo layer in step S628. This is a focus pull-in instruction. In Example 2, when the recording layer focus drive voltage generation circuit 1305 receives the jump voltage output start instruction three times in total, it outputs three types of voltages corresponding to the instruction contents. The recording layer focus drive voltage generation circuit 1305 of this embodiment also performs the same operation as that of the second embodiment. Furthermore, in this embodiment, when the servo layer focus drive voltage generation circuit 1309 receives a jump voltage output start instruction three times in total, the servo layer focus drive voltage generation circuit 1309 outputs three types of voltages corresponding to the instruction content.

  After instructing the stop of the recording layer focus control in step S604, the system control circuit 1301 instructs the recording layer focus drive voltage generation circuit 1305 and the servo layer focus drive voltage generation circuit 1309 to start the first jump voltage output ( Step S624).

  If the amplitude of the R_FE signal is less than the predetermined threshold Th_FJ1 in step S607 (Yes in step S607), the system control circuit 1301 records the recording layer focus drive voltage generation circuit 1305 and the servo layer focus drive voltage generation circuit 1309. Is then instructed to start the second jump voltage output (step S625).

  Furthermore, when the amplitude of the R_FE signal is greater than or equal to the predetermined threshold Th_FJ2 in step S609 (in the case of Yes in step S609), the system control circuit 1301 records the recording layer focus drive voltage generation circuit 1305 and the servo layer focus drive voltage generation circuit 1309. Is then instructed to start the third jump voltage output (step S626).

  After the jump voltage is output, the process waits until the recording layer focus pull-in timing comes in step S611. When it is the recording layer focus pull-in timing (Yes in step S611), the system control circuit 1301 instructs the focus pull-in to the recording layer by setting the R_FON signal to high (step S612). Furthermore, the recording layer focus drive voltage generation circuit 1305 and the servo layer focus drive voltage generation circuit 1309 are instructed to stop the jump voltage output (step S627).

  Further, following step S613, the system control circuit 1301 of this embodiment sets the S_FON signal to High to instruct focus pull-in to the servo layer (step S628). After step S628, the system control circuit 1301 changes the TON signal from low level to high level to instruct the start of tracking control (step S618). As a result, the switch 1311 is switched and the tracking control is turned on. Thus, the focus jump process is completed (step S619).

  Next, the operation of each part in the focus jump process of this embodiment will be described with reference to FIG. FIG. 12 is a waveform diagram showing signals at various parts of the focus control system during the focus jump process from the L0 layer to the L1 layer. Of the waveforms shown in FIG. 12, (a) to (d) are signals relating to the recording layer, and (e) to (h) are signals relating to the servo layer. The tracking control system signal is not shown.

  12A shows the R_FE signal, FIG. 12B shows the output signal of the recording layer focus drive voltage generation circuit 1305, FIG. 12C shows the R_FON signal, and FIG. 12D shows the R_FOR signal. 12E shows the S_FE signal, FIG. 12F shows the output signal of the servo layer focus drive voltage generation circuit 1309, FIG. 12G shows the S_FON signal, and FIG. 12H shows the R_FOD signal.

  The polarity of the output voltage (b) of the recording layer focus drive voltage generation circuit 1305 and the polarity of the output voltage (f) of the servo layer focus drive voltage generation circuit 1309 are the same as those in the first embodiment.

  As the operation of the focus control system in the focus jump process, the operation at the time t1 is the same as that in the second embodiment, and the description thereof is omitted. At time t2, the system control circuit 1301 changes the R_FON signal from High level to Low level as shown in FIG. 12C, and turns off the recording layer focus control. At the same time, the system control circuit 1301 issues an instruction to the recording layer focus drive voltage generation circuit 1305 and the servo layer focus drive voltage generation circuit 1309 to start output of the jump voltage. When the start of jump voltage output is instructed, each of the two circuits outputs a jump voltage, and sequentially outputs three values as shown in the period from time t2 to time t5 in FIG. And The voltage during the period from time t2 to t3 will be referred to as the first jump voltage for any circuit. The same applies to the second jump voltage and the third jump voltage.

  The first jump voltage, the second jump voltage, and the third jump voltage in the recording layer focus drive voltage generation circuit 1305 are Vr1_FJ, Vr2_FJ, and Vr3_FJ. In addition, the first jump voltage, the second jump voltage, and the third jump voltage in the servo layer focus drive voltage generation circuit 1309 are Vs1_FJ, Vs2_FJ, and Vs3_FJ.

  At time t1, the recording layer focus drive voltage generation circuit 1305 outputs the first jump voltage Vr1_FJ. As a result, the actuator 1212 is accelerated and the movement of the focal point of the laser beam having a wavelength of 405 nm is started. The direction of movement of the focal point of the laser beam having a wavelength of 405 nm is a direction in which the objective lens 1211 approaches the optical disc 101. At the same time, the servo layer focus drive voltage generation circuit 1309 outputs the first jump voltage Vs1_FJ. This accelerates the relay lens and starts moving the focal point of the laser light having a wavelength of 650 nm. The direction of movement of the focus of the laser beam having a wavelength of 650 nm is a direction in which the focus of the laser beam having a wavelength of 650 nm moves away from the optical disc 101.

  As described in the second embodiment, when the actuator 1212 is driven in the direction approaching the optical disc 101 by the first jump voltage output from the recording layer focus drive voltage generation circuit 1305, the focus of the laser beam having a wavelength of 650 nm is also increased. It is driven in a direction approaching 101. However, in this embodiment, the relay lens is simultaneously driven in a direction to cancel the movement of the focal point of the laser beam having a wavelength of 650 nm. In this embodiment, it is assumed that the first jump voltage Vs1_FJ output from the servo layer focus drive voltage generation circuit 1309 is a value calculated as a voltage that cancels the movement of the focus of the laser beam having a wavelength of 650 nm. As a result, even if the first jump voltage is output, the focal point of the laser beam having a wavelength of 650 nm does not move and remains in the vicinity of the servo layer.

  As can be seen from FIG. 12, the second jump voltage Vs2_FJ output from the servo layer focus drive voltage generation circuit 1309 is similarly a laser having a wavelength of 650 nm by the second jump voltage Vr2_FJ output from the recording layer focus drive voltage generation circuit 1305. It is assumed that the value is calculated as a voltage that cancels the movement of the focal point of light. The same applies to the third jump voltage Vs3_FJ output from the servo layer focus drive voltage generation circuit 1309.

  As a result of the operation of the recording layer focus drive voltage generation circuit 1305 and the servo layer focus drive voltage generation circuit 1309 as described above, the focus of the laser beam having a wavelength of 650 nm is moved during the period from time t2 to time t5 when the jump voltage is applied. Instead, it stays in the vicinity of the servo layer.

  When the system control circuit 1301 detects that it is the recording layer focus pull-in timing at time t5, the R_FON signal is changed from the Low level to the High level and output as shown in FIG. When the R_FON signal changes to High level, the switch 1303 is switched, and the output of the recording layer focus control circuit 1302 is supplied to the actuator drive circuit 108. That is, the recording layer focus control is turned on, and the focus pull-in to the recording layer is performed.

  Further, the system control circuit 1301 issues an instruction to the recording layer focus drive voltage generation circuit 1305 at time t5 to instruct the output stop of the jump voltage. With this operation, the focus jump from the L0 layer to the L1 layer is completed with respect to the recording layer focus control system.

  Furthermore, in this embodiment, the system control circuit 1301 changes the S_FON signal from the Low level to the High level and outputs it as shown in FIG. When the S_FON signal changes to the high level, the switch 1307 is switched, and the output of the servo layer focus control circuit 1306 is supplied to the relay lens drive circuit 109. That is, the servo layer focus control is turned on, and focus pull-in to the servo layer is performed. In this way, it is possible to perform the focus pull-in to the servo layer without performing the relay lens sweep.

  Compared with FIG. 6 which is the flowchart of the second embodiment, according to the present embodiment, the steps from step S614 to step S617 can be omitted. For this reason, the time required for the focus jump can be shortened by the time required for the relay lens sweep. By the above operation, the optical disc apparatus of Embodiment 4 can realize focus control and tracking control suitable for an optical disc having a servo layer and a recording layer.

  This embodiment is an embodiment for realizing a focus jump operation for an optical disc having a servo layer and a recording layer. This embodiment corresponds to a modification of the fourth embodiment. The configuration of the optical disk apparatus of the present embodiment is the same as that of FIG.

  Hereinafter, the operation of the system control circuit 1301 in this embodiment will be described with reference to the flowchart of the focus jump process shown in FIG. In addition, the same number is attached | subjected about FIG. 6 which is the flowchart of Example 2, and FIG. 11 which is the flowchart of Example 4, and description is abbreviate | omitted.

  The difference between the present embodiment and the fourth embodiment is the output start instruction of the third jump voltage in step S629, the output start instruction of the fourth jump voltage in step S630, and the processing after step S631.

  If the amplitude of the R_FE signal is greater than or equal to the predetermined threshold Th_FJ2 in step S609 (Yes in step S609), the system control circuit 1301 starts outputting the third jump voltage to the recording layer focus drive voltage generation circuit 1305. (Step S629).

  After the output of the third jump voltage, the process waits until the recording layer focus pull-in timing comes in step S611. When it is the recording layer focus pull-in timing (Yes in step S611), the system control circuit 1301 instructs the focus pull-in to the recording layer by setting the R_FON signal to high (step S612). Further, the recording layer focus drive voltage generation circuit 1305 is instructed to stop the jump voltage output (step S630). Further, the system control circuit 1301 of this embodiment instructs the servo layer focus drive voltage generation circuit 1309 to start the fourth jump voltage output subsequent to step S613 (step S631).

  After step S630, as in the second embodiment, the system control circuit 1301 waits until the servo layer focus pull-in timing is reached in step 615, and if it is the servo layer focus pull-in timing (Yes in step S615), the system control circuit 1301 instructs the focus pull-in process to the servo layer by setting the S_FON signal to High (step S616).

  Subsequent to step S616, the system control circuit 1301 instructs the servo layer focus drive voltage generation circuit 1309 to stop the fourth jump voltage output (step S632). After step S632, the system control circuit 1301 changes the TON signal from low level to high level to instruct the start of tracking control (step S618). As a result, the switch 1311 is switched and the tracking control is turned on. Thus, the focus jump process is completed (step S619).

  Next, the operation of each part in the focus jump process of this embodiment will be described with reference to FIG. FIG. 14 is a waveform diagram showing signals at various parts of the focus control system during the focus jump process from the L0 layer to the L1 layer. Of the waveforms shown in FIG. 14, (a) to (d) are signals relating to the recording layer, and (e) to (h) are signals relating to the servo layer. The tracking control system signal is not shown.

  14A shows the R_FE signal, FIG. 14B shows the output signal of the recording layer focus drive voltage generation circuit 1305, FIG. 14C shows the R_FON signal, and FIG. 14D shows the R_FOR signal. 14E shows the S_FE signal, FIG. 14F shows the output signal of the servo layer focus drive voltage generation circuit 1309, FIG. 14G shows the S_FON signal, and FIG. 14H shows the R_FOD signal.

  The polarity of the output voltage (b) of the recording layer focus drive voltage generation circuit 1305 and the polarity of the output voltage (f) of the servo layer focus drive voltage generation circuit 1309 are the same as those in the first embodiment. The description of the same parts as those in FIG. 12 that is the waveform diagram of the fourth embodiment will be omitted.

  According to the flowchart of FIG. 13, the third jump voltage is output only to the output signal (b) of the recording layer focus drive voltage generation circuit 1305 as indicated from time t4 to time t5. In addition, the waveform output as the third jump voltage in the output signal (f) of the servo layer focus drive voltage generation circuit 1309 according to the fourth embodiment is output from time t6 to time t7 in FIG. This corresponds to the fourth jump voltage in this embodiment. That is, in the present embodiment, the third jump voltage that was simultaneously output by the recording layer focus drive voltage generation circuit 1305 and the servo layer focus drive voltage generation circuit 1309 in Embodiment 4 is output at different timings.

  In this embodiment, the focus jump is performed according to the following procedure. First, the first jump voltage and the second jump voltage are output simultaneously from the recording layer focus drive voltage generation circuit 1305 and the servo layer focus drive voltage generation circuit 1309 as in the fourth embodiment. From time t4 to time t5, the third jump voltage is output only from the recording layer focus drive voltage generation circuit 1305 as shown in FIG. Thereby, the actuator 1212 is decelerated.

  During the period from time t4 to time t5, the output of the recording layer focus drive voltage generation circuit 1305 is not changed, so that the focus of the laser light having a wavelength of 650 nm moves and moves away from the servo layer. From time t6 to time t7, the fourth jump voltage is output from the servo layer focus drive voltage generation circuit 1309 as shown in FIG. As a result, the relay lens is driven to cancel the distance traveled by the focus of the laser beam having a wavelength of 650 nm by the third jump voltage, and as a result, the focus of the laser beam having a wavelength of 650 nm returns to the vicinity of the servo layer. The focus pull-in of the servo layer of this embodiment can be determined by detecting the S-shaped zero cross point of the S_FE signal (e) as in the second embodiment.

  Next, effects of the present embodiment will be described. In the fourth embodiment, the servo layer focus drive voltage generation circuit 1309 outputs a jump voltage having the same shape so as to cancel the jump voltage output from the recording layer focus drive voltage generation circuit 1305.

  However, the servo layer focus control system is not controlled while the jump voltage is applied, and the focus of the laser beam having a wavelength of 650 nm may be separated from the servo layer. Note that FIG. 12 used in Example 4 describes that the focal point of the laser beam having a wavelength of 650 nm does not move away from the servo layer. If focus pull-in is performed on the servo layer with the focus of the laser beam having a wavelength of 650 nm being away from the servo layer, focus pull-in may fail.

  This is because, in general, the focus error signal has an S-shaped waveform, and when the vertex of the S-shape is exceeded, the tilt is reversed and focus control becomes impossible. In order to perform stable focus pull-in, it is necessary to perform focus pull-in at the timing at which the focus of the laser light passes through the focus pull-in layer, which is the center of the S-shaped waveform.

  Therefore, in this embodiment, the third jump voltage that was simultaneously output by the recording layer focus drive voltage generation circuit 1305 and the servo layer focus drive voltage generation circuit 1309 in Embodiment 4 is output at different timings. As a result, the focus of the laser beam having a wavelength of 650 nm is once moved away from the servo layer, and then brought closer again to bring the focus into the servo layer.

  Accordingly, it is possible to reliably detect the S-shaped zero cross point of the S_FE signal (e) and perform the focus pull-in to the servo layer. By performing the focus pull-in by detecting the S-shaped zero cross point, the focus pull-in can be performed at the timing when the focal point of the laser beam having a wavelength of 650 nm coincides with the servo layer. With the above operation, focus pull-in to the servo layer can be performed stably.

  Furthermore, in this embodiment, a time-consuming relay lens sweep can be omitted, and the application time of the fourth jump voltage from time t6 to time t7 is short. Therefore, as in the fourth embodiment, there is an effect that the time required for the focus jump can be shortened by the time required for the relay lens sweep. With the above operation, the optical disc apparatus of Embodiment 5 can realize focus control and tracking control suitable for an optical disc having a servo layer and a recording layer.

  In the embodiments related to the focus jump after the second embodiment, the focus jump from the L0 layer to the L1 layer, or from the L1 layer to the L0 layer has been described as an example. However, the present invention can be similarly applied even when a focus jump waveform is used to perform a focus jump on a plurality of layers at once. The focus jump in the case of jumping a plurality of layers at once can be realized by the same method as Blu-ray Disc having three or four recording layers.

  The spindle control circuit 1313 in the above embodiment is configured to perform CAV control based on the output signal of the spindle motor 104. However, the rotation method of the spindle motor 104 is not limited to this method. For example, a configuration in which rotation control is performed to keep the linear velocity constant based on information read from the optical disc 101 may be employed. This control is called CLV control. In the case of this rotation method, the spindle control circuit 1313 performs control without using the output signal of the spindle motor 104.

  In the above embodiment, the laser power control circuit 1201 is configured to drive both the laser diode 1202 and the laser diode 1215, but each laser diode may be provided with a laser power control circuit unique to each laser diode.

  The aberration correction element 1209 may be disposed at a position that affects both the 405 nm optical system and the 650 nm optical system. For example, the aberration correction element 1209 may be disposed between the quarter wavelength plate 1210 and the dichroic mirror 1208.

  In the above embodiment, the recording layer is irradiated with laser light having a wavelength of 405 nm and the servo layer is irradiated with laser light having a wavelength of 650 nm. However, the wavelength of each laser light is not limited to this. Absent. Further, the wavelength of the laser beam irradiated to the recording layer may be the same as the wavelength of the laser beam irradiated to the servo layer, and further, the laser beam from a single laser diode is divided to obtain the recording layer. And the structure which irradiates with respect to a servo layer may be sufficient.

  In the above embodiment, as described with reference to FIG. 15, the structure of the optical disk 101 is such that the recording surface coated with the recording film is laminated in the film thickness direction. However, the application range of the present invention is not limited to the optical disk having the structure shown in FIG. Any optical disc having a servo layer capable of generating a focus error signal and a recording layer capable of generating a focus error signal is applicable.

  That is, there is no recording surface coated with a recording film, and the recording layer focus error may occur even in an optical disc in which information is recorded or reproduced by irradiating a uniform medium with a laser beam having a wavelength of 405 nm. The present invention can be applied if a signal can be generated. For example, a uniform medium has a structure for specifying the recording position of information inside the recording medium, and the structure records the information in a plane by generating a recording layer focus error from the output signal of the detector. Thus, the present invention can be similarly applied to an optical disc in which a recording layer is formed.

  In the above embodiment, as described with reference to FIG. 15, the servo layer of the optical disc 101 has been described as having a physical guide groove structure. However, the servo layer only needs to have a track for tracking servo, and may not have a physical groove structure. Specifically, the servo layer may have no groove structure and may have a structure in which tracking pits are formed. Even when there is no groove structure, a tracking error signal can be generated from a pit if a pit is formed. Therefore, the pit row functions as a track to be followed, and tracking servo can be performed on the track (pit row).

  Furthermore, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. In addition, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of a certain embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  In addition, each of the above-described configurations may be configured such that some or all of them are configured by hardware, or are implemented by executing a program by a processor. Further, the control lines and information lines indicate what is considered necessary for the explanation, and not all the control lines and information lines on the product are necessarily shown. Actually, it may be considered that almost all the components are connected to each other.

DESCRIPTION OF SYMBOLS 101 ... Optical disk 102 ... Optical pick-up 103 ... Signal processing circuit 104 ... Spindle motor 105 ... Servo error signal generation circuit 106 ... Reproduction signal processing circuit 107 ... Spindle drive circuit 108 ... Actuator drive circuit 109 ... Relay lens drive circuit 110 ... Aberration correction element Drive circuit 111 ... Slider motor 112 ... Slider drive circuit 1201 ... Laser power control circuit 1202 ... Laser diode 1203 ... Collimator lens 1204 ... Beam splitter 1205 ... Condensing lens 1206 ... Power monitor 1207 ... Polarizing beam splitter 1208 ... Dichroic mirror 1209 ... Aberration Correction element 1210 ... 1/4 wavelength plate 1211 ... Objective lens 1212 ... Actuator 1213 ... Condensing lens 1214 ... Detector 1215 ... Laser diode 12 6 ... Collimator lens 1217 ... Beam splitter 1218 ... Condensing lens 1219 ... Power monitor 1220 ... Polarizing beam splitter 1221 ... Relay lens 1222 ... Condensing lens 1223 ... Detector 1301 ... System control circuit 1302 ... Recording layer focus control circuit 1303 ... Switch 1304 ... adder 1305 ... recording layer focus drive voltage generation circuit 1306 ... servo layer focus control circuit 1307 ... switch 1308 ... adder 1309 ... servo layer focus drive voltage generation circuit 1310 ... tracking control circuit 1311 ... switch 1312 ... slider control circuit 1313 ... Spindle control circuit

Claims (17)

For an optical disc having a servo layer having tracks formed thereon and a plurality of recording layers stacked in the film thickness direction, the recording layer is irradiated with the first laser beam, and the servo layer is irradiated with the second laser beam. An optical disc device for recording or reproducing information,
An optical disk rotating section for rotating the optical disk about a predetermined rotation axis;
An objective lens that focuses the light spot of the first laser beam and the light spot of the second laser beam on the optical disc;
Objective lens driving means for driving the objective lens;
Servo layer focal position changing means for displacing a focal position of the second laser beam on the servo layer;
A light detection unit that outputs an electrical signal corresponding to the amount of light reflected from the optical disc;
A servo layer focus error signal generation unit that generates a focus error signal for the servo layer from an output signal of the light detection unit;
A recording layer focus error signal generation unit that generates a focus error signal for the recording layer from an output signal of the light detection unit;
Based on the servo layer focus error signal, a servo layer focus control unit that drives the servo layer focus position changing unit to perform focus control of the second laser beam on the servo layer;
A recording layer focus control unit that controls the focus of the first laser beam with respect to the recording layer by driving the objective lens driving unit based on the recording layer focus error signal;
From the state where the focus control of the servo layer focus control unit with respect to the servo layer and the focus control of the recording layer focus control unit with respect to the recording layer are not started, for the first laser beam and the second laser beam, When each focus pull-in,
When the servo layer focus control unit starts focus control on the servo layer so as to perform focus pull-in to the servo layer, the recording layer focus control unit performs the recording operation so as to perform focus pull-in to the recording layer. An optical disc apparatus, which is after a timing at which focus control is started for any one of the layers. The optical disc apparatus according to claim 1,
Servo layer focus drive voltage output unit for driving the servo layer focus position changing unit by outputting a predetermined voltage for focus control on the servo layer;
A recording layer focus drive voltage output unit for driving the objective lens driving means by outputting a predetermined voltage for focus control on the recording layer;
After the recording layer focus driving voltage output unit drives the objective lens driving unit in a direction perpendicular to the optical disc, the recording layer focus control unit performs focus pull-in to one of the recording layers. Start focus control,
An optical disc apparatus characterized in that after the servo layer focus drive voltage output unit drives the servo layer focus position changing unit, the servo layer focus control unit starts focus control so as to perform focus pull-in to the servo layer. . The optical disc apparatus according to claim 1,
Servo layer focus drive voltage output unit for driving the servo layer focus position changing unit by outputting a predetermined voltage for focus control on the servo layer;
A recording layer focus drive voltage output unit for driving the objective lens driving means by outputting a predetermined voltage for focus control on the recording layer;
After the recording layer focus driving voltage output unit drives the objective lens driving unit in a direction perpendicular to the optical disc, the recording layer focus control unit performs focus pull-in to one of the recording layers. Start focus control,
After the servo layer focus drive voltage output unit drives the servo layer focus position changing unit, the servo layer focus control unit starts focus control so as to perform focus pull-in to the servo layer,
The servo layer focus drive voltage output unit drives the servo layer focus position changing unit before the recording layer focus control unit starts focus control so as to perform focus pull-in to one of the recording layers. An optical disc apparatus characterized by starting an operation. The optical disc apparatus according to claim 1,
A tracking error signal generation unit that generates a tracking error signal for the servo layer from an output signal of the light detection unit;
A tracking control unit that performs tracking control by driving the objective lens driving unit based on the tracking error signal;
Since the focus control of the servo layer focus control unit for the servo layer and the focus control of the recording layer focus control unit for the recording layer are not started, the recording layer focus control unit is one of the recording layers. After starting the focus control for the servo layer, the servo layer focus control unit starts the focus control for the servo layer,
Thereafter, the tracking control unit starts tracking control for the servo layer. For an optical disc having a servo layer having tracks formed thereon and a plurality of recording layers stacked in the film thickness direction, the recording layer is irradiated with the first laser beam, and the servo layer is irradiated with the second laser beam. An optical disc device for recording or reproducing information,
An optical disk rotating section for rotating the optical disk about a predetermined rotation axis;
An objective lens that focuses the light spot of the first laser beam and the light spot of the second laser beam on the optical disc;
Objective lens driving means for driving the objective lens;
Servo layer focal position changing means for displacing a focal position of the second laser beam on the servo layer;
A light detection unit that outputs an electrical signal corresponding to the amount of light reflected from the optical disc;
A servo layer focus error signal generation unit that generates a focus error signal for the servo layer from an output signal of the light detection unit;
A recording layer focus error signal generation unit that generates a focus error signal for the recording layer from an output signal of the light detection unit;
Based on the servo layer focus error signal, a servo layer focus control unit that drives the servo layer focus position changing unit to perform focus control of the second laser beam on the servo layer;
Based on the recording layer focus error signal, a recording layer focus control unit that drives the objective lens driving unit to perform focus control of the first laser beam on the recording layer;
A recording layer focus drive voltage output unit for driving the objective lens driving means by outputting a predetermined voltage for focus control on the recording layer;
A period during which the recording layer focus drive voltage output unit outputs a jump voltage for performing a focus jump operation for driving the objective lens driving unit to move the light spot of the first laser beam to another recording layer; An optical disc apparatus, wherein output of the servo layer focus control unit is stopped. The optical disc apparatus according to claim 5, wherein
After the output of the jump voltage by the recording layer focus drive voltage output unit, the recording layer focus control unit starts focus control on any one of the recording layers so as to perform focus pull-in to the recording layer,
The servo layer focus control unit starts focus control on the servo layer so as to perform focus pull-in to the servo layer,
The timing at which the servo layer focus control unit starts focus control on the servo layer is after the timing at which the recording layer focus control unit starts focus control on any one of the recording layers. An optical disc device characterized. The optical disc apparatus according to claim 5, wherein
A servo layer focus drive voltage output unit for driving the servo layer focus position changing means by outputting a predetermined voltage for focus control on the servo layer;
After the servo layer focus drive voltage output unit drives the servo layer focus position changing means, the servo layer focus control unit starts focus control on the servo layer so as to perform focus pull-in to the servo layer. An optical disc apparatus characterized by the above. The optical disc apparatus according to claim 5, wherein
A servo layer focus drive voltage output unit for driving the servo layer focus position changing means by outputting a predetermined voltage for focus control on the servo layer;
After the servo layer focus drive voltage output unit drives the servo layer focus position changing means, the servo layer focus control unit starts focus control on the servo layer so as to perform focus pull-in to the servo layer,
The servo layer focus drive voltage output unit changes a direction in which the focus position of the second laser beam moves according to a direction in which the focus position of the first laser beam moves by the focus jump operation. An optical disc apparatus for driving the servo layer focal position changing means as described above. The optical disc apparatus according to claim 5, wherein
A servo layer focus drive voltage output unit for driving the servo layer focus position changing means by outputting a predetermined voltage for focus control on the servo layer;
After the output of the jump voltage by the recording layer focus drive voltage output unit, the recording layer focus control unit starts focus control on any one of the recording layers so as to perform focus pull-in to the recording layer,
After the servo layer focus drive voltage output unit drives the servo layer focus position changing means, the servo layer focus control unit starts focus control on the servo layer so as to perform focus pull-in to the servo layer,
Before the recording layer focus control unit starts focus control on any one of the recording layers, the servo layer focus drive voltage output unit starts an operation of driving the servo layer focus position changing unit. An optical disc device characterized by the above. The optical disc apparatus according to claim 5, wherein
When the number of layers moved by the focus jump operation is equal to or greater than the predetermined number of layers, the output of the servo layer focus control unit is stopped while the recording layer focus drive voltage output unit outputs the jump voltage. ,
When the number of layers moved by the focus jump operation is less than a predetermined number of layers, the output of the servo layer focus control unit is also stopped during the period when the recording layer focus drive voltage output unit outputs the jump voltage. An optical disc device characterized by not. The optical disc apparatus according to claim 5, wherein
When the number of layers moved by the focus jump operation is equal to or greater than the predetermined number of layers, the output of the servo layer focus control unit is stopped while the recording layer focus drive voltage output unit outputs the jump voltage. ,
When the number of layers moved by the focus jump operation is less than a predetermined number, the characteristics set in the servo layer focus control unit during the period when the recording layer focus drive voltage output unit outputs the jump voltage And the output of the servo layer focus control unit is not stopped. For an optical disc having a servo layer having tracks formed thereon and a plurality of recording layers stacked in the film thickness direction, the recording layer is irradiated with the first laser beam, and the servo layer is irradiated with the second laser beam. An optical disc device for recording or reproducing information,
An optical disk rotating section for rotating the optical disk about a predetermined rotation axis;
An objective lens that focuses the light spot of the first laser beam and the light spot of the second laser beam on the optical disc;
Objective lens driving means for driving the objective lens;
Servo layer focal position changing means for displacing a focal position of the second laser beam on the servo layer;
A light detection unit that outputs an electrical signal corresponding to the amount of light reflected from the optical disc;
A servo layer focus error signal generation unit that generates a focus error signal for the servo layer from an output signal of the light detection unit;
A recording layer focus error signal generation unit that generates a focus error signal for the recording layer from an output signal of the light detection unit;
Based on the servo layer focus error signal, a servo layer focus control unit that drives the servo layer focus position changing unit to perform focus control of the second laser beam on the servo layer;
Based on the recording layer focus error signal, a recording layer focus control unit that drives the objective lens driving unit to perform focus control of the first laser beam on the recording layer;
Servo layer focus drive voltage output unit for driving the servo layer focus position changing means by outputting a predetermined voltage for focus control on the servo layer;
A recording layer focus drive voltage output unit for driving the objective lens driving means by outputting a predetermined voltage for focus control on the recording layer;
A period during which the recording layer focus drive voltage output unit outputs a jump voltage for performing a focus jump operation for driving the objective lens driving unit to move the light spot of the first laser beam to another recording layer; An optical disc apparatus characterized in that the output of the servo layer focus control unit is not stopped. The optical disc apparatus according to claim 1 or 5, wherein
The optical disc apparatus has a structure in which recording surfaces coated with a recording film are laminated in a film thickness direction. The optical disc apparatus according to claim 1 or 5, wherein
The optical disk is recorded or reproduced by irradiating a uniform medium with a first laser beam,
A structure for specifying a recording position of information in the uniform medium;
An optical disc apparatus, wherein a recording layer is formed by recording information in a planar shape by generating the recording layer focus error from an output signal of the light detection unit by the structure. An optical disk having a servo layer with tracks formed thereon and a plurality of recording layers stacked in the film thickness direction is irradiated with a first laser beam on the recording layer, and a second laser beam is irradiated on the servo layer. A focus control method in an optical disc apparatus for recording or reproducing information,
From the state where the focus control of the second laser beam on the servo layer and the focus control of the first laser beam on the recording layer are not started, the first laser beam and the second laser beam are When each focus pull-in,
The timing for starting the focus control of the second laser light on the servo layer so as to focus the second laser light on the servo layer is the timing at which the first laser light is applied to the recording layer. A focus control method, characterized by being after a timing at which focus control of the first laser beam is started with respect to any one of the recording layers so as to perform focus pull-in. An optical disk having a servo layer with tracks formed thereon and a plurality of recording layers stacked in the film thickness direction is irradiated with a first laser beam on the recording layer, and a second laser beam is irradiated on the servo layer. A focus control method in an optical disc apparatus for recording or reproducing information,
In a focus jump operation for moving the light spot of the first laser beam irradiated to any one of the recording layers to another recording layer,
A focus control method comprising: stopping focus control of the second laser beam on the servo layer during a period in which a jump voltage for performing the focus jump is output. The focus control method according to claim 16, comprising:
The focus jump operation includes an operation of changing a focal position of the second laser light irradiated to the servo layer,
The focal position of the second laser beam irradiated on the servo layer in accordance with the direction in which the focal position of the first laser beam irradiated on the recording layer by the focus jump operation moves. A focus control method characterized in that the direction in which the lens moves is changed.

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