JPH04176023A - Optical type information recording/reproducing device - Google Patents

Abstract

PURPOSE:To stabilize a track jump, and to shorten settling time by obtaining displacement from the center of a track of a light spot by a fuzzy inference from a tracking error signal and a light intensity signal and controlling the position of the light spot so as to conform to a predetermined pattern. CONSTITUTION:The position of a light spot between tracks is inferred by a fuzzy inference from a tracking error signal TES and a light intensity signal SUM, and the position of the light spot is controlled so that the inferred positional output conforms with a predetermined pattern and a track is jumped. Consequently, the quantity of an overshoot at the time of the leading-in of a target track can be reduced. The track is operated by a closed loop as much as possible. That is, since the track is operated in the open loop only for the output period of kick pulses KP, the title reproducer is difficult to be effected by disturbance such as the eccentricity of a disk, and is not effected even by the drive sensibility change of a tracking actuator 38. Accordingly, a settling time is shortened, and a track jump is stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical information recording/reproducing device such as an optical disk device that performs track jumping to a target track.

[Prior Art] Optical information recording and reproducing devices such as optical discs use tracking control to control a light spot to follow information tracks provided concentrically or spirally, and optical control to access arbitrary information tracks. Track jump control is performed to move the spot in a direction across the track.

Track jumping methods include an open-loop method typified by pan-pan control and a closed-loop method. As one of the F& A method has been proposed in which the light spot is moved to a desired track by controlling the light spot based on an error signal.

FIG. 9 is a block diagram of such a track jump method, and FIGS. 10 and 11 are waveform diagrams for explaining its operation. In FIG. 9, 1 is a tracking error signal generation circuit that generates a tracking error signal according to the positional deviation between the optical spot and the information track, 2 is an equalizer for phase compensation of the servo system, 3 is an inverting amplifier, and 4 is a A non-inverting amplifier, 5 a changeover switch for polarity selection, 6 a driving amplifier, 7 a coil, 8 a tracking mirror driven by the coil 7, 9 a controller for controlling the switch 5, 10 a tracking Comparator for detecting that the error signal exceeds the zero level, 1
1 is a speed detector for detecting the operating speed of the tracking actuator. For speed detection, a method is used in which a speed signal is obtained by performing F-V conversion on a tracking error signal. The drive amplifier 6, the inverting amplifier 3. The non-inverting amplifiers 4 are OP amplifiers ○p, +, op2, OF, respectively.
It is formed using 2.

First, a case in which one-track jump is performed using this method will be explained. In FIG. 10, it is assumed that the tracking servo is turned on at point a and the track jumps to point b on the adjacent track. At this time, as shown in Figure (B), if one of the outputs of the amplifier 4 and the inverting amplifier 3 is selected by the changeover switch 5 and the tracking error signal is appropriately inverted, the stable point of the servo will be only point b. , the light spot will converge at point b. Even when jumping over multiple tracks, based on the above-mentioned one-track jump, it is sufficient to consider that point b is an adjacent track as shown in Fig. 11, and speed detector 1
The jump is performed while suppressing unnecessary acceleration due to the action of the speed servo by No. 1.

[Problems to be Solved by the Invention] However, in such a track jumping method, speed detection may not be performed normally when the number of tracks to be jumped is small, so the light spot continues to be accelerated until it reaches the target track. In other words, since speed control cannot be performed appropriately, the relative speed to the track upon reaching the target track becomes very large, making it easy to fail in pulling in the track, and also lengthening the settling time. Speed detection is a problem especially when doing one-track jumps,
It seems difficult to perform a stable one-track jump.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide an optical information recording/reproducing device that can stably perform one-track jumps, etc., and can perform track jumps in a short settling time. .

[Means and effects for solving the problem] In the present invention, by performing fuzzy inference using a tracking error signal and a light intensity signal as input, a position signal that monotonically increases or decreases with respect to the displacement of the optical spot from the center of the information track is obtained. The track jump is performed by controlling the light spot position so that the position signal matches a predetermined pattern, and the speed control for the track jump is appropriately controlled according to the position signal. This makes it possible to perform track jumps stably and in a short settling time.

[Example 1 Hereinafter, the present invention will be specifically described with reference to the drawings.

FIGS. 1 to 7 relate to the first embodiment of the present invention.
Figure 2 is a block diagram showing the refinement of the track jump control circuit in the first embodiment, Figure 2 is a configuration diagram of the optical disk device in the first embodiment, and Figure 3 is a standardized tracking error signal and optical intensity signal. FIG. 4 is a waveform diagram for explaining the operation of the first embodiment, FIG. 5 is a characteristic diagram showing membership functions, and FIG. 6 is an explanatory diagram showing fuzzy inference rules.
FIG. 7 is an explanatory diagram illustrating the fuzzy inference rules of FIGS. 5 and 6.

As shown in FIG. 2, an optical disk device 21 as an optical information recording/reproducing device of the first embodiment has a spindle motor 2
An optical head 24 is disposed so as to be movable in the radial direction T of the optical disk 23 (in other words, the direction perpendicular to the tracks), facing an optical disk 23 as an optical recording medium which is rotationally driven by a VCM 25. It is moved by a mechanism.

The optical head 24 has a laser diode 26 as a light beam generating means, and the light beam of the laser diode 26 passes through a prism or the like (not shown), is focused by an objective lens 27, and is irradiated onto the optical disk 23. . The light reflected by the optical disk 23 is guided to a photodetector 28 via an objective lens 27 and the like.

The output of the photodetector 28 is the access servo control port 1i! which performs access control and servo control. g, and a signal processing circuit 30 that generates a reproduction signal and a signal for recording by controlling the light emission of the laser diode 26.
is input.

Further, the objective lens 27 is held by a lens actuator (not shown), and this lens actuator is used as an access lens.
Controlled by two servo control circuits. For example, in a normal servo state, the lens actuator is controlled based on the tracking error signal and the focus error signal, and is controlled to maintain the tracking state and the focus state.

On the other hand, FIG. 1 shows the components of the track jump control circuit 31 when accessing the target track by track jumping.

A tracking error signal is output from a tracking error signal detection means 32 composed of a differential amplifier or the like into which the outputs of a pair of detection elements constituting the photodetector 28 are input (according to the amount of displacement of the light spot from the center of the track). ) The tracking error signal TBS' passes through the first phase compensation circuit 33 for improving the loose characteristics and is sent to the contact a of the first changeover switch SWI.
is input to the fuzzy inference processor 3 via a first gain control amplifier (abbreviated as VCA) 34.
5 is input.

The first change-over switch SWI is a change-over switch that changes between tracking servo and track jump modes, and a change-over signal SC from the controller 36 that generates various timing signals in response to a track jump command JP.
Switching is performed by I. The tracking error signal TES' is also input to the controller 36 at the initial time, the amplitude of the tracking error signal TES' is detected, and the gain of the first VCA 34 is adjusted using the detected amplitude value. Adjustments are made so that the tracking error signal TBS normalized from

The signal that has passed through the first switch SWI is supplied to a tracking actuator 38 that moves the light spot (which moves the objective lens 27 and irradiates the optical disc 23) via a driver 37 that amplifies the current.

On the other hand, a light intensity signal detection means 4 constituted by an adder or the like that adds the outputs of a pair of detection elements constituting the photodetector 28.
The light intensity signal SUM' (proportional to the intensity of the reflected light from the optical disk 23) outputted from the second VCA 42
The output signal is input to the fuzzy inference processor 35 via the . or,
This light intensity signal SUM' is also input to the controller 36 at the initial time, its amplitude value is detected, and the gain of the second VCA 42 is adjusted based on this amplitude value, and the standardized light is output from this second VCA 42. Strength signal SUM
is input to the fuzzy inference processor 35.

As shown in FIG. 3, the waveforms of the standardized tracking error signal TBS and optical intensity signal SUM change in the form of a sine wave and a cosine wave, with one cycle extending from the center of a certain track to the center of an adjacent track, respectively. Each will change from -1 to +1. The fuzzy inference processor 35 to which these standardized tracking error signal TBS and optical intensity signal SUM are input performs fuzzy calculations using these two signals as input, and calculates a nearly linear result with respect to the displacement of the optical spot from the track center. Position signal PDE
Output T.

This position signal PDET is input to the subtracter 43, and is subtracted from the movement pattern signal PCNT from the movement pattern generation means 44, which instructs the movement of the light spot at the time of track jump, and this subtracted signal is used in the track jump control loop. Second phase compensation circuit 4 for improving characteristics
5 and is input to the contact a of the second changeover switch SW2.

The moving pattern generating means 44 is configured such that the waveform and the like of the moving pattern PCNT are controlled by the controller 36.

A kick pulse KP outputted from the kick pulse generating means 46 for accelerating the optical spot in a desired direction at the start of a track jump is input to the contact point of the second (switch) switch SW2. This kick pulse KP
The generation and polarity of is controlled by a controller 36,
Also, the switching of the second changeover switch SW2 is also performed by the controller 3.
It is controlled by the signal SC2 from 6. The output of this second switch SW2 is applied to the contacts of the first changeover switch SW1.

In the normal tracking servo state, contact a of the first switch SWI is turned on, and the optical substrate is controlled to track the current track using a signal based on the tracking error signal TES'.

Further, when accessing a target track close to the current track from the current track, for example, the first switch S
After the contact W1 is switched on so that the contact of the second switch SW2 is turned on and the kick pulse KP is supplied to the tracking actuator 38, the contact a of the second changeover switch SW2 is switched on. is turned on, and a signal obtained by subtracting the position signal PDET from the fuzzy inference processor 35 from the movement pattern signal PCNT is supplied to the tracking actuator 38, and then the contact of the second switch SW2 is turned on to control the position. I am trying to switch to .

The operation of this first embodiment will be explained with reference to FIG. 4, for example, access operation by one track jump.

First, during the initial operation, the tracking servo is turned off, the optical spot is moved, the tracking error signal TES' and the optical intensity signal SUM'' at that time are taken into the controller 36, the amplitudes of each are detected, and the first Adjust the gain of VCA 34 and second VCA 42,
Standardized tracking error signals TF, S and light intensity signal SUM from the first VCA 34 and second VCA 42
is input to the fuzzy inference processor 35.

Thereafter, when the jump command JP is input to the controller 36 as shown in FIG. 4(a), the first switch SW1 is switched by the signal SCI from the controller 36 (the contact point is (on), and the tracking servo (track following servo) is off. At the same time, as shown in FIG. 4(C), the second switch SW2 is also switched by the signal SC2 to turn on the contact.
A kick pulse KP as shown in FIG. 2D is transmitted from the kick pulse generating means 44 to the tracking actuator 38 via the second switch SW2, the first switch SWI, and the driver 37. This kick pulse KP acts to accelerate the light spot from the current track toward the target l/rack, and therefore the polarity of the kick pulse KP is reversed between the inner and outer circumferential sides.

After the kick pulse KP is output, the second switch SW2 is switched to turn on the contact a, and the output of the second phase compensation circuit 45 is selected. At the same time, the fuzzy inference processor 35 starts inference and enters the spot position control mode.

In this mode, the tracking actuator 38 uses a predetermined movement pattern signal PCNT (see FIG. 4(a)) output from the movement pattern generation means 44 and a fuzzy inference processor 35 that generates a signal corresponding to the light spot position. Since it is driven by the difference from the obtained optical spot position signal PDET shown in FIG.
The light spot approaches the adjacent track along the movement pattern signal PCNT.

Incidentally, the fuzzy inference processor 35 is shown in FIG. 4(f),
((1> Or a monotonically increasing position signal PDET is generated from the standardized tracking error signal TBS and light intensity signal SUM shown in FIG. I am trying to generate .

That is, the movement pattern signal PCNT is the target movement pattern, and the device signal PDET constituted by the fuzzy inference processor 35 generates a signal for movement in the target movement pattern. The subtracter 43 converts the moving pattern signal PCN.
A signal obtained by subtracting the position signal PDET from T is sent to the tracking actuator 3 via the second phase compensation means 45, etc.
8, the light spot almost corresponds to the moving pattern signal PC
It is moved in a pattern along the NT. Then, when the time corresponding to when the light spot reaches the vicinity of the target track has elapsed from the generation time of the movement pattern signal PCNT, the controller 36 switches the first switch SWI so that contact a is turned on again, and the normal At the same time that the tracking servo is turned on, the fuzzy inference in the fuzzy inference processor 35 is stopped.

In this state, the light spot is in the vicinity of the target track, and the moving speed is also controlled within the range where the track can be pulled in by controlling the spot position M. Therefore, the track can be reliably pulled in, and overshoot can be minimized to achieve the target track. The settling time required to access the track is also reduced.

Next, the operation of fuzzy inference by the fuzzy inference processor 35 in this embodiment will be explained.

FIG. 5 shows the membership functions defined within the fuzzy inference processor 35, and the tracking error signal T
It is commonly defined for BS and optical intensity signal SUM.

In the definition of the membership function above, NL (Nega
tive Large), NS (Ne
gative Small).

ZR (7ero), P S (Positi
ve 5IIllall), PL(Po5it
The tracking error signal TBS and optical intensity signal SUM are both standardized to vary within a range of ±1. Even if this range fluctuates a little, it will not be fatal due to the nature of fuzzy, and the inference result can be obtained that is not much different from the normal state. However, since it cannot cope with extreme level fluctuations, the signal level is standardized during initialization. When the light spot moves from the center of a track toward an adjacent track, TES and SUM change in the form of a sine wave and a cosine wave, respectively, as shown in FIG.

If we consider a sine or cosine wave varying from 0 to 1, the value when the spot is at its center is 0.
It will be 71. Therefore, in order to facilitate the creation of inference rules, the parks of PS and NS of the membership functions are set to ±0 and 7, and the peaks of PL and NL are set to ±1.

Then, the inference rule 48 shown in FIG. 6 was set.

Inference rule 48 in FIG. 6 uses a "simplification method" in which the rule consequent is a constant, taking into account the linearity of interpolation in the part where no rules are written and the ease of handling in cases like this example. We are planning to use As a result of the inference, a continuous value of 1 to 0 for the rack center and 8 for the adjacent track center is obtained as the output PDET, but it is difficult to distinguish between the vicinity of the track center and the vicinity of the adjacent l/rack center. Therefore, no inference is performed near the center of each track, and 1 to 7 between tracks.
We are planning to output the value of . Therefore, since the position signal PDET cannot be obtained at the start of a track jump, the spot can be forcibly moved in the direction of the target track by the kick pulse KP immediately after the start of the jump, as shown in Figure 4, to enable position detection. When the position is reached, the switch is made to switch to the spot position servo. Similarly, when approaching the target track, position detection becomes impossible, so when the target track approaches to a certain extent, the spot position servo is turned off, and the l~ racking servo is used to pull into the target track.

Here, an inference method will be described for a case where a detected value of 0.8 as TBS and -06 as SUM is obtained as an example. This is the value that would be obtained if the sub-I was located at about 35% between the tracks, and therefore a value of about 28 should be obtained as a result of the inference. From Fig. 5, TBS=0.8 fits 03 for label PL and 07 for PS, while S(JM=-
0,6 is 0.15 for label ZR and 0 for NS
．． 85 is found to be compatible. Rule 48 in Figure 6 that applies to this is “if TES=PL
and 5UH = ZRthen PDE = 2'' and °
' if TES=PS and 5UH=NSthe
n PDET-3''. If the MIN method is used to calculate the and in the if part, each rule will be adopted at a degree of 0.15 and 07, respectively.

If the result is obtained by the center of gravity method, (2 lines 0.15 + 3 lines 0
．． 7) / <0.15+0.7) -2,82, which is found to be almost the same as the stated value.

Also, from the inference rule shown in FIG. 7 which illustrates FIGS. 5 and 6, position signals PDE are obtained from the bottom row and the third row, respectively.
Inferred values 0.15 and 07 for determining T are obtained, and when the centroid method is applied to these, a similar value 282 is obtained.

As explained above, according to the first embodiment, in the optical disk device having the tracking error signal detection means 32 and the light intensity signal detection means 41, the tracking error signal TBS and the light intensity signal SUM are used to detect the difference between the tracks of the light spot. The position of the target track is estimated using fuzzy inference, and the light spot position is controlled so that the estimated position output matches a predetermined pattern to perform a track jump. This reduces the amount of overshoot when pulling in the target track and reduces the settling time. can be shortened. In addition, since it operates in a closed loop as much as possible (open loop only during the output period of the kick pulse KP), it is less susceptible to disturbances such as disk eccentricity, and is not affected by changes in drive sensitivity of the racking actuator 38, so it is always stable. It is possible to jump.

In the first embodiment, fuzzy inference is not performed near the center of the track, the light spot is driven by a kick pulse at the start of a jump, and when pulling into a target track, the tracking servo is returned to before reaching the target track. As shown in FIG. 8, it is also possible to estimate the light spot position in the entire range between tracks by appropriately switching the fuzzy inference rules during a jump, and perform a track jump using only the spot position servo.

In the second embodiment, the two fuzzy inference rules 51 and 52 shown in FIGS. 8(a) and 8(b) are switched midway.

Therefore, the track jump control circuit in this second embodiment differs from the circuit 31 shown in FIG. 1 in that it does not include the kick pulse generating means 46 and the second switch SW2.
The output of the second phase compensation circuit 45 is connected to the first switch SWI.
The voltage is applied to the contacts.

Further, the fuzzy inference processor 35 is connected to a controller 36
Inference is performed by switching the fuzzy inference rule 51 shown in FIG. 8(a) to the fuzzy inference rule 52 shown in FIG. 8(b) by a switching signal from . In this case, the switching timing may be, for example, controlled by time control (management) by the controller I/roller 36, such that it is switched around the time when the labels ZR of the tracking error signal TES and NL of the SUM are used in the fuzzy inference rule 51. Movement pattern generating means 4
It may also be possible when the movement pattern command for Sakura becomes 4.

According to the second embodiment, it is possible to access the target track by l~rack jump in a short settling time without using the kick pulse KP.

Note that, by fuzzy inference, a position signal that increases monotonically with respect to the amount of displacement of the light spot from the track center is not limited to a monotonous increase, but may be generated.

Further, although the present invention has been described with respect to accessing an adjacent track by a one-track jump, it is clear that the present invention can also be applied to a jump over a plurality of tracks. In this case, the one-track jump according to the first embodiment etc. may be repeatedly performed, or the position signal PDET explained in the first embodiment etc. may be generated for multiple tracks and access by track jump may be performed. Also good.

Furthermore, when switching the rules based on fuzzy inference as in the second embodiment, it is sufficient if the position signal monotonically increases or decreases in a portion from the current track to the target track. In the case of access spanning multiple tracks, the speed may be controlled to be decelerated near the target track.

Note that the present invention can be applied not only to access by track jump but also to tracking.

Note that a dedicated fuzzy inference chip can of course be used in the fuzzy inference processor of this embodiment.
It can also be realized in software using a general microprocessor or the like. Alternatively, it is also possible to use a method in which inference results for all inputs are calculated in advance, the results are written into memory, and the inference results are obtained by decoding according to the inputs.

[Effects of the Invention] As described above, according to the present invention, the tracking error signal detection means outputs a tracking error signal corresponding to the amount of displacement of the light beam focused on the recording medium from the center of the information track. and a light intensity signal detection means for detecting the amount of reflected light from the recording medium.

A fuzzy inference is performed using the tracking error signal and the light intensity signal as input, a position signal that monotonically increases or decreases with respect to the displacement amount of the light spot from the center of the information track is generated, and a position signal is calculated in advance from the position signal. Since the track jump is performed by controlling the light spot position so as to match a predetermined pattern, the amount of overshoot when pulling in the target track is reduced, the settling time is shortened, and a stable track jump can be performed.

[Brief explanation of the drawing]

FIGS. 1 to 7 relate to the first embodiment of the present invention.
Figure 2 is a block diagram showing the configuration of the track jump control circuit in the first embodiment, Figure 2 is a configuration diagram of the optical disk device in the first embodiment, and Figure 3 shows the standardized tracking error signal and optical intensity signal. 4 is a waveform diagram for explaining the operation of the first embodiment, FIG. 5 is a characteristic diagram showing the membership function, FIG. 6 is an explanatory diagram showing the fuzzy inference rule,
7 is an explanatory diagram illustrating the fuzzy inference rules of FIGS. 5 and 6, FIG. 8 is an explanatory diagram illustrating the fuzzy inference rule in the second embodiment of the present invention, and FIG. 9 is the configuration of the conventional example. 10 and 11 are explanatory diagrams of the operation of the conventional example. 21... Optical disk device 23... Optical disk 2
4... Optical head 31... Track jump control circuit 32... Tracking error signal detection means 35...
Fuzzy inference processor 36...Controller 38...Tracking actuator 41...Light intensity signal detection means 44...Movement pattern generation means 46...Kick pulse generation means Fig. 2 Fig. 3 Fig. 4 Fig. 5 Figure 6 Figure 7 TES SUM -I 0 1-1
Li 1 Figure 11 Procedural Amendment (Voluntary) December 1991 68 1゜Case Indication 1990 Patent Application No. 303337 2, Title of Invention Optical Information Recording and Reproducing Device 3, Amendment to the Person Making the Amendment Related Patent Applicant Representative Satoshi Shimoyama Department 1, ``In short'' will be deleted from the 5th line of IM page 5 of the Meihiko. 2. In the 13th line of page 5 of the specification, the phrase "...do it stably..." is corrected to "...stay...J." 3. In the 14th line of page 5, the text ``Perform Torak Ji Young with...J'' should be corrected to ``Perform with...''. 4. In the 5th line of page 6 of the specification, the statement ``...appropriately controls the speed M of the pump according to the position signal'' is replaced by ``...
・Correct the position and speed of sub and y to the appropriate position when moving. 5. In the 4th line of page 11 of the statement, the words "...movement miracle..." will be corrected to "...movement trajectory...". 6. In the 12th page of the specification, from line 17 to line 18, the statement ``...turns on the contact of the second switch SW2 to perform position control...'' is changed to ``... first switch S
Turn on contact a of WI and use tracking servo...
I will correct it. 7. In the 14th page, line 17 of the specification, “...4th
Figure (a > J has been corrected to ``...Figure 4 (e)''). 8. The statement ``This example... 9. On the 7th line of page 16 of the statement, correct the phrase ``In this condition...'' to ``At this time...''. 10 , in the 9th line of page 16 of the specification, ``...controlled...j'' was replaced with ``...controlled...
・Corrected to ``. 11. Delete "Required to access target truck" from line 11 to line 12 on page 16 of the statement. 12. In the 16th line of page 17 of the specification, the phrase "...the value when it is at the center is..." is replaced by "...the sine wave (or cosine wave) when it is at the midpoint." The value of is...". 13. In the 18th line of page 17 of the statement, the words "...Park..." will be corrected to "...Peak...". 14. On the 4th line of page 18 of the specification, the words "...we are planning to use..." will be corrected to "...we are using...". 15. On the 18th line of page 19 of the specification, the words "stated..." will be corrected to "expected..." 16. On the 15th line of page 22 of the specification, the phrase "increasing serious condition..." will be corrected to "monotonically decreasing..." 17. Delete "Also, you may do the second example..." from lines 4 to 10 on page 23 of the statement Namacha.

Claims (1)

[Scope of Claims] 1. A tracking error that generates a substantially sinusoidal tracking error signal having one period equal to the distance between the information tracks according to the amount of displacement of a light spot focused on the recording medium from the center of the information track. An optical information recording/reproducing device comprising a signal detection means and a light intensity signal detection means for detecting an amount of reflected light from the recording medium, the apparatus performing fuzzy inference using the tracking error signal and the light intensity signal as input. , generating a position signal that monotonically increases or decreases with respect to the amount of displacement of the light spot from the center of the information track, and controlling the position of the light spot based on the position signal. Recording and playback device. 2. The optical information recording and reproducing apparatus according to claim 1, wherein track jumping is performed by controlling the position of the light spot so that the position signal matches a predetermined pattern. 3. The optical information recording/reproducing apparatus according to claim 1, wherein the fuzzy inference is not performed near the center of the information track.