JP2002216357A - Phase change disk, its initialization device, and optical disk drive device - Google Patents

Abstract

(57) [Problem] To provide a phase change disk capable of performing accurate focus offset adjustment, an initialization device thereof, and an optical disk drive device. SOLUTION: The initialization apparatus for a phase change disk according to the present invention is an initialization apparatus for setting a rewritable phase change disk 1 to a recordable state, wherein the initialization laser beam is rotated while the phase change disk 1 is rotated. Is irradiated on the phase change disk while wobbling in the radial direction of the phase change disk 1. In the apparatus for initializing a phase change disk according to the present invention, it is preferable that the amount of the wobbling is equal to or larger than the initial feed pitch.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a rewritable phase change disk, an initialization device for making the phase change disk recordable, and an optical disk drive using the phase change disk.

[0002]

2. Description of the Related Art An optical disk drive device shown in FIG. 7 is conventionally known. This optical disk drive device includes a spindle motor 102 for rotating a disk-shaped phase change disk 101, an optical pickup device 103 movably arranged in the radial direction of the phase change disk 101 rotated by the spindle motor 102, Control device 104 and track error signal detection device 1
05 and a controller 106. The focus control device 104 is connected to the optical pickup device 103 and the controller 106. Also, the track error signal detection device 105 is an optical pickup device 10
3 and the controller 106. This optical disk drive device is a CD-RW, DVD-RAM
Alternatively, data is written to and read from a phase change disk 101 such as a DVD-RW. CD-RW, D
Phase change disk 1 such as VD-RAM or DVD-RW
01 is in an amorphous state or a metastable crystalline state in a part immediately after the phase change film is formed,
As it is, it cannot be used in an optical disk drive. Therefore, the phase change disk 101 needs to be initialized to crystallize the phase change film before shipping. Normally, initialization of the phase change disk 101 is performed by rotating the laser beam having a wavelength of approximately 10 μm × 100 μm to 60 μm while the phase change disk 101 is being rotated.
The irradiation is performed by irradiating the phase-change disk 101 while feeding it in the radial direction so as to have a pitch of about the same. FIG. 8 shows the trajectory A of the initialization laser beam on the phase change disk 101. The trajectory A of the initialization laser beam is spiral, and the spiral pitch p is about 60 μm.

FIG. 9 shows a state of a track error signal when the optical pickup device 103 is moved in the radial direction of the phase change disk 101 by using the phase change disk 101 that has been initialized as described above in an optical disk drive. The track error signal is obtained by a push-pull signal from a pre-groove having a pitch of 0.7 to 1.6 μm formed in advance on the phase change disk. The track error signal fluctuates at the initialization pitch p as shown in FIG. This variation causes a problem when adjusting the focus offset of the optical disk drive. The necessity and method of adjusting the focus offset of the optical disk drive will be described below. The optical disk drive detects a focus signal for focusing. The focus signal detection method generally uses an astigmatism method, a knife edge method, a spot size method, or the like. However, an error occurs in the focus signal due to the thickness of the substrate of the phase change disk (optical disk) 101, temperature change, aging, and the like. In order to correct the error, the work of adjusting the focus offset is performed by the optical disk drive device when necessary.

For example, when a phase-change disk (optical disk) 101 is inserted into an optical disk drive, the phase-change disk 101 is rotated, and after focusing is performed, before the track is retracted, the focus signal is changed to about five steps. Are sequentially applied to measure the amplitude of the track error signal to detect the focus offset. FIG. 4 shows the state of the amplitude of the track error signal when offsets corresponding to −2 μm, −1 μm, 0 μm, 1 μm, and 2 μm are sequentially applied. The track error signal can be observed because the phase change disk 101 has an eccentricity of several tens of μm. FIG. 5 shows the relationship between the amplitude of the track error signal in FIG. 4 and the defocus due to the applied offset. FIG. 5 shows that when a quadratic approximation curve is obtained for data having 5 points and 5 points, the defocus is 0 μm.
The peak is at m. FIGS. 4 and 5 show examples in which there is no error in the focus signal. If there is an error in the focus signal, the peak of the quadratic approximation curve does not become 0 μm. For example, if there is a peak at 1 μm, the focus signal has an error of 1 μm, and an offset equivalent to 1 μm may be applied to the focus signal.

[0005]

However, if there is a change in the track error signal as shown in FIG. 9, it becomes extremely difficult to detect the focus offset signal, or the focus offset signal is erroneously detected. There is a problem. This is because the track error signal can be observed due to the eccentricity at the time of rotation of the phase change disk, but in the case shown in FIG. 9, not only the defocus but also the amplitude of the track error signal varies greatly due to the eccentricity. . SUMMARY OF THE INVENTION It is an object of the present invention to provide a phase change disk capable of accurately adjusting a focus offset in an optical disk drive device by suppressing fluctuations in a track error signal amplitude in a radial direction caused by initialization of a phase change disk, an initialization device thereof, and an optical disk. A drive device is provided.

[0006]

According to a first aspect of the present invention, there is provided an initialization apparatus for setting a rewritable phase change disk to a recordable state, wherein the phase change disk is rotated. In this state, the initialization laser beam is irradiated on the phase change disk while wobbling in a radial direction of the phase change disk. According to a second aspect of the present invention, in the phase change disk initializing apparatus according to the first aspect, the amount of the wobbling is set to be equal to or larger than the initialization feed pitch. According to a third aspect of the present invention, in the rewritable phase change disk, the initialization laser beam is irradiated on the phase change disk while wobbling in a radial direction of the phase change disk while the phase change disk is being rotated. Characterized by being initialized. According to a fourth aspect of the present invention, in the phase change disk according to the third aspect, the amount of the wobbling is equal to or larger than an initialization pitch. A fifth aspect of the present invention is characterized in that focus offset adjustment is performed using the phase change disk according to the third or fourth aspect.

[0007]

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing an apparatus for initializing a phase change disk according to one embodiment of the present invention. As shown in FIG. 1, a phase change disk initialization apparatus according to one embodiment of the present invention includes a spindle motor 2 for rotating a disk-shaped phase change disk 1,
An optical pickup device 3, a wobble control device 4, and a feed control device 5 arranged so as to be movable in the radial direction of the phase change disk 1 rotated by the spindle motor 2.
, A focus control device 6, a track error signal detection device 7, and a controller 8. The wobble control device 4 is connected to the optical pickup device 3.
The feed control device 5 is connected to the optical pickup device 3. The focus control device 6 includes the optical pickup device 3
And the controller 8. The track error signal detection device 7 is also connected to the optical pickup device 3 and the controller 8. The optical pickup device 3 includes a semiconductor laser device 9 that emits a laser beam.
A half mirror 10 that reflects a part of the laser beam from the semiconductor laser device 9 to change the optical path of a part of the laser beam, and converges the laser beam from the half mirror 10 and And a light receiving element 12 for receiving the reflected light from the surface of the phase change disk 1 via the objective lens 11 and the half mirror 10. Further, the optical pickup device 3 has a focusing actuator 13 and a tracking actuator 14. The focus control device 6 and the track error signal detection device 7
It is connected to the light receiving element 12. Focus control device 6
Are connected to a focusing actuator 13. The wobble control device 4 is connected to the tracking actuator 14.

The focus control device 6 generates a focus error signal from the laser beam incident on the light receiving element 12 and drives the focusing actuator 13 to control the distance between the objective lens 11 and the phase change disk 1 to be constant. . The wobble control device 4 applies a wobble signal to the tracking actuator 14 and
1 is oscillated radially with respect to the phase change disk 1.
The feed control device 5 moves the entire pickup device 3 in the radial direction with respect to the phase change disk 1 when the phase change disk 1 is initialized. The phase change disk initialization device irradiates the phase change disk 1 with the initialization laser beam while wobbling in the radial direction of the phase change disk 1 while the phase change disk 1 is being rotated by the spindle motor 2. The change disk 1 is initialized. The phase change disk 1 is a CD-RW, DVD-R
It is composed of AM or DVD-RW. As shown in FIG. 2, the trajectory B of the initialization laser beam on the phase change disk 1 has a spiral shape meandering in the radial direction. Also,
The meandering amount (wobbling amount) d of the trajectory B of the initialization laser beam is desirably equal to or larger than the initialization feed pitch p.

FIG. 3 shows a case where the phase change disk 1 initialized by the phase change disk initialization apparatus of FIG. 1 is mounted on the optical disk drive of FIG. 6 and the optical pickup device 3 is moved in the radial direction. The state of a track error signal is shown. Since the initialization laser beam is meandering, the fluctuation of the amplitude of the track error signal caused by the radial position as shown in FIG. 8 also occurs due to the rotation of the phase change disk 1, and is not influenced by the radial position. That is, by performing initialization while wobbling the initialization laser beam in the radial direction of the phase change disk 1,
The fluctuation of the track error signal amplitude due to the initialization is determined by the wobbling frequency regardless of the position in the radial direction.

Next, an optical disk drive using the phase change disk 1 will be described with reference to FIG. FIG. 6 is a schematic diagram showing an optical disk drive device. As shown in FIG. 6, this optical disk drive device is obtained by deleting the wobble control device 4 in the phase change disk initialization device of FIG. That is, this optical disk drive device
It includes a spindle motor 2, an optical pickup device 3, a feed control device 5, a focus control device 6, a track error signal detection device 7, and a controller 8.
The phase change disk 1 is rotated by a spindle motor 2. The optical pickup device 3 of the optical disk drive outputs a focus error signal and a track error signal. The focus error signal is sent to the focus control device 6
Controls the distance between the objective lens 11 and the phase change disk 1 (defocused state). The defocus state is changed to, for example, −2 μm by the instruction signal from the controller 8.
When the state of the track error signal is detected while sequentially changing to m, −1 μm, 0 μm, 1 μm, and 2 μm, FIG.
Is obtained. The track error signal can be observed because the optical disc has an eccentricity of several tens of μm. FIG. 5 shows the relationship between the amplitude of the track error signal in FIG. 4 and the defocus due to the applied offset. In FIG. 5, when a quadratic approximation curve is obtained for data having five data points and five data points, the peak is at a defocus of 0 μm. FIGS. 4 and 5 show examples in which there is no error in the focus signal. If there is an error in the focus signal, the peak of the quadratic approximation curve does not become 0 μm. For example, if there is a peak at 1 μm, the focus signal has an error of 1 μm, and an offset equivalent to 1 μm may be applied to the focus signal.

[0011]

As described above, according to the first or third aspect of the present invention, when the phase change disk is initialized to make the phase change disk recordable, the initialization laser beam is used. By performing initialization while wobbling in the radial direction of the phase change disk, the fluctuation of the track error signal amplitude due to initialization is determined by the wobbling frequency regardless of the position in the radial direction. , Accurate focus offset adjustment is possible. According to the invention described in claim 2 or 4, claim 1 is provided.
In the invention described in the third aspect, by making the amount of wobbling equal to or larger than the feed pitch of the initialization, it is possible to reliably eliminate the variation in the track error signal amplitude due to the radial position due to the initialization. According to the fifth aspect of the present invention, an error due to a position in the radial direction does not occur at the time of focus offset adjustment, so that an optical disk drive device with good data recording and reproducing performance can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an apparatus for initializing a phase change disk according to one embodiment of the present invention.

FIG. 2 is a diagram for explaining a trajectory of an initialization laser beam on a phase change disk by the phase change disk initialization device of FIG. 1;

3 shows a state of a track error signal when the optical pickup device is moved in the radial direction with the phase change disk initialized by the phase change disk initialization device of FIG. 1 mounted on the optical disk drive device of FIG. 6; FIG.

FIG. 4 is a diagram for explaining a track error signal by the optical disk drive device of FIG. 6;

5 is a diagram for explaining a relationship between the amplitude of a track error signal in FIG. 4 and defocus due to an applied offset.

FIG. 6 is a schematic diagram showing an optical disk drive using an optical disk according to an embodiment of the present invention.

FIG. 7 is a schematic diagram showing a conventional optical disk drive device.

FIG. 8 is a diagram for explaining a trajectory of an initialization laser beam on a phase change disk by the optical disk drive device of FIG. 6;

9 is a diagram for explaining a state of a track error signal when the initialized phase change disk is mounted on the optical disk drive device of FIG. 7 and the optical pickup device is moved in the radial direction.

[Explanation of symbols]

1 phase change disk, 2 spindle motor, 3 optical pickup device, 4 wobble control device, 5 feed control device, 6 focus control device, 7 track error signal detection device, 8 controller, 9 semiconductor laser device, 10 half mirror, 11 Objective lens, 12 light receiving element, 13 focusing actuator, 14
Tracking actuator.

Claims (5)

[Claims] 1. An initialization apparatus for recording a rewritable phase-change disk in a recordable state while wobbling an initialization laser beam in a radial direction of the phase-change disk while the phase-change disk is rotating. An apparatus for initializing a phase change disk, which irradiates the phase change disk. 2. The phase change disk initialization apparatus according to claim 1, wherein the amount of the wobbling is equal to or larger than an initialization feed pitch. 3. In a rewritable phase change disk, an initialization laser beam is irradiated onto the phase change disk while wobbling in the radial direction of the phase change disk while the phase change disk is being rotated. A phase change disc characterized by being made into a phase change disc. 4. The phase change disk according to claim 3, wherein the amount of wobbling is equal to or larger than an initialization pitch. 5. An optical disk drive device for performing focus offset adjustment using the phase change disk according to claim 3.