JPH08147725A - Disc playing device - Google Patents

Abstract

(57) [Summary] [Object] The present invention has been made for the purpose of realizing high precision, high performance, and high speed access of an optical head feeding means for a disk playing device. [Configuration] The objective lens 1 is initially offset in the tracking direction by an objective lens actuator, and an offset is applied to the voltage applied to the traverse motor 6. [Effect] By driving the objective lens while offsetting, it is possible to double the access speed with the same feeding accuracy of the optical head feeding device as the conventional one. Further, it is possible to improve the feed accuracy up to about twice even at the same access speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc playing device of a system in which a light spot is projected on a disc-shaped recording medium to optically record / reproduce information.

[0002]

2. Description of the Related Art In recent years, disk players have been diversified in their applications such as MD players, CD players, CD-ROM players, etc. year by year, and have become more dense, high performance and high quality.
The value added is increasing. Especially MD player / CD-RO
The demand for M players is on the rise, and there is a demand for higher speed access, smaller size, thinner size, and higher performance.

The present invention relates to an optical head feeding means for a disc playing device, and conventionally, many reports have been made on the technique relating to the optical head feeding means for the disc playing device.

The conventional optical head feeding means for a disk playing device will be described in detail below with reference to FIGS. 5, 6, 7 and 8.

FIG. 5 is an exploded perspective view of an optical head feeding means for a disk playing device in a conventional example, FIG. 6 is a schematic view of an optical head feeding means for a disk playing device in a conventional example, and FIG. 7 is a conventional example. FIG. 8 is a schematic view of an objective lens actuator of an optical head feeding means for a disc playing device, and FIG. 8 is a relationship between a moving amount of an objective lens in a tracking direction and a drive voltage of a traverse motor in the conventional optical head feeding means for a disc playing device. It is the figure which showed.

In FIGS. 5, 6 and 7, the X direction indicates the tracking direction (+ is the outer peripheral side), the Y direction is the tangential direction, and the Z direction is the focusing direction (+ is the direction toward the disc). Is.

In FIGS. 5, 6 and 7, 1 is an optical head, 2 is an objective lens, 3 is an objective lens actuator, 4 is a main shaft, 5 is a sub shaft, 6 is a traverse motor, 7 is a reduction gear, and 8 is Lead screw, 9 is feed nut, 1
0 is a disk, 11 is a spindle motor, 12 is a traverse base, 13 is a turntable, 14 is a centering ring, and 15 is a spindle motor 11 which is a traverse base 1.
2 is a motor mounting plate for mounting to 2 (6 to 9 are optical head feeding means).

The operation of the optical head feeding means of the disk playing device constructed as described above will be described below.

First, the spindle motor 11 is attached to the motor attachment plate 15 attached to the traverse base 12, and the turntable 13 is attached to the shaft portion of the spindle motor 11 at a prescribed height with high precision. . A centering ring 14 and a turntable magnet (not shown) are fixed inside the turntable 13, and the disk 10 is clamped (clamp plate) by pulling a clamp plate (not shown) by the magnetic force of the turntable magnet. It is sandwiched between the turntable 13 and the turntable 13, and the spindle 10 rotates the disk 10 to rotate the disk 10 at a specified rotation speed.

The optical head 1 is held by a main shaft 4 and a sub shaft 5 and is movable in the radial direction of the disk 10. The driving force of the traverse motor 6 is transmitted to the lead screw 8 via the reduction gear 7 and the feed nut 9 moves the optical head 1 in the radial direction of the disk 10.

FIG. 8 shows the relationship between the amount of movement of the objective lens 2 in the tracking direction and the drive voltage of the traverse motor 6, where the horizontal axis is time and the vertical axis is the amount of movement of the objective lens 2 in the tracking direction and the vertical axis. Traverse motor 6
Is shown (however, the eccentricity of the disk is not shown).

When playing an optical disc, the objective lens 2 is driven by the objective lens actuator 3 in the radial direction of the disc, and a drive voltage corresponding to the amount of movement of the objective lens 2 in the tracking direction is applied to the traverse motor 6.

The amount of movement of the optical head 1 is determined by the reduction ratio calculated from the pitch of the lead screw 8 and the number of teeth of the reduction gear 7, and the rotation angle of the traverse motor 6 in one cogging. When the rotational force generated by the drive voltage applied to the traverse motor 6 exceeds the static load, the optical head moves a distance corresponding to the rotation angle of the traverse motor 6 for one cogging.

[0014]

However, in the conventional structure as described above, the larger the offset amount from the optical axis of the objective lens, the more the aberration of the light spot formed on the disk increases, and the offset amount is regulated. If the value is exceeded, the recording / playback performance of the disk will deteriorate sharply. However, there has been a problem that the access speed of the optical head feeding means is significantly deteriorated by improving the feeding accuracy (resolution) of the optical head feeding means in order to improve the information recording / reproducing ability.

Further, there has been a problem that there is a limit in reducing the feeding accuracy (resolution) of the optical head feeding means in order to reduce the access speed of the optical head.

In view of the above-mentioned problems of the prior art, the present invention has been made for the purpose of providing a high-speed optical head feeding means and a high-precision optical head feeding means for a disk playing device.

[0017]

In order to solve the above problems, an optical head feeding means for a disk playing device according to the present invention comprises:
An objective lens, an objective lens actuator for driving the objective lens in the focus direction and the tracking direction, an optical head equipped with the objective lens actuator, and an optical head feeding means for moving the optical head in the radial direction of the disk are provided. The lens is initially offset in the tracking direction by the objective lens actuator, and the optical head is fed and driven by the optical head feeding means.

[0018]

According to the present invention, with the above structure, the objective lens actuator offsets the initial position of the objective lens in the direction opposite to the moving direction of the optical head to perform recording and reproduction, so that the feeding accuracy of the optical head feeding device is the same. However, the offset amount of the objective lens is reduced to about 1/2, and the aberration of the light spot formed on the disc can be significantly reduced, so that the recording / reproducing capability can be significantly improved.

Further, even when the same recording / reproducing capability is required, the feeding accuracy of the optical head feeding device is about 1 /
Therefore, the access speed can be increased (about twice the speed).

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of an optical head feeding means for a disk playing device according to the present invention will be described below with reference to FIGS.
This will be described in detail with reference to FIGS. 2, 3, and 4.

FIG. 1A shows an exploded perspective view of an optical head feeding means for a disk playing device according to the first embodiment of the present invention.

FIG. 2 is a schematic view of an optical head feeding means for a disk playing device according to the first embodiment of the present invention.

FIG. 3 is a schematic view of the objective lens actuator of the optical head feeding means for the disk playing device in the first embodiment of the present invention.

In FIG. 1A, FIG. 2 and FIG.
The direction is the tracking direction (+ is the outer peripheral side), the Y direction is the radial direction, and the Z direction is the focus direction (+ is the direction toward the disk).

In FIG. 1A, FIG. 2 and FIG. 3, 1
Is an optical head, 2 is an objective lens, 3 is an objective lens actuator, 4 is a main axis, 5 is a sub axis, 6 is a traverse motor,
7 is a reduction gear, 8 is a lead screw, 9 is a feed nut, 10 is a disc, 11 is a spindle motor, 12 is a traverse base, 13 is a turntable, 14 is a centering ring, and 15 is a spindle motor 11 on the traverse base 12. It is a motor mounting plate for mounting (6 ~
9 is an optical head feeding means).

The operation of the optical head feeding means for a disk playing device constructed as described above will be described below.

First, the spindle motor 11 is attached to the motor attachment plate 15 attached to the traverse base 12, and the turntable 13 is accurately attached to the shaft portion of the spindle motor 11 at a prescribed height. . A centering ring 14 and a turntable magnet (not shown) are fixed inside the turntable 13, and a disc 10 is clamped by pulling a clamp plate (not shown) by the magnetic force of the turntable magnet. The rotation of the spindle motor 11 causes the disk 10 to rotate at a specified rotation speed.

The optical head 1 is held by the main shaft 4 and the sub shaft 5 and is movable in the radial direction of the disk 10. The driving force of the traverse motor 6 is transmitted to the lead screw 8 via the reduction gear 7 and the feed nut 9 moves the optical head 1 in the radial direction of the disk 10.

FIG. 1B is a diagram showing the relationship between the amount of movement of the objective lens 2 in the tracking direction and the drive voltage of the traverse motor 6, where the horizontal axis represents time and the vertical axis represents the tracking direction of the objective lens 2, respectively. It shows the amount of movement and the voltage applied to the traverse motor 6 (however, the amount of eccentricity of the disk is not shown).

When the optical disc is played, the objective lens 2 is driven by the objective lens actuator 3 in the radial direction of the disc, and a drive voltage corresponding to the amount of movement of the objective lens 2 in the tracking direction is applied to the traverse motor 6.

The amount of movement of the optical head 1 is determined by the reduction ratio calculated from the pitch of the lead screw 8 and the number of teeth of the reduction gear 7, and the rotation angle of the traverse motor 6 in one cogging. When the rotational force generated by the drive voltage applied to the traverse motor 6 exceeds the static load, the optical head 1 moves a distance corresponding to the rotation angle of the traverse motor 6 for one cogging.

The objective lens actuator 3 is the disk 1
An initial offset current of about ½ of the distance corresponding to the rotation angle of one cogging is applied in the radial direction of 0 in the direction opposite to the moving direction during performance.

As described above, according to the first embodiment, the initial position of the objective lens 2 is offset in the direction opposite to the moving direction of the optical head 1 (the negative X direction in the figure) for recording and reproduction. By doing so, the offset amount (moving distance from the optical axis) of the objective lens 2 becomes about 1/2 of that of an apparatus in which the feeding accuracy of the optical head feeding means is equal, and the light spot formed on the disk 10 becomes smaller. Since the aberration characteristic is greatly improved, it is possible to significantly improve the recording / reproducing ability. In addition, the same recording and recording as the device without the initial offset of the objective lens by the objective lens actuator 3
Even when the reproducing capability is realized, the feeding accuracy of the optical head feeding means can be reduced to about 1/2, and the access speed can be increased (about twice the speed).

Next, the second embodiment will be described. First
The difference from the embodiment is that the information recording / reproducing performance (jitter value, C / N, crosstalk, etc.) is determined by the amount of offset in the tracking direction of the objective lens 2 in the offset region of the objective lens 2 within a specified range. That is, the initial offset amount of the objective lens 2 in the tracking direction is applied so as to be the best.

As described above, according to the second embodiment, by determining the offset amount of the objective lens 2 from the information recording / reproducing performance of the optical head 1, the light spot can be obtained with the same optical head feeding means. It is possible to significantly reduce the aberration, and it is possible to further improve the recording / reproducing characteristics of the disc playing device.

Next, a third embodiment will be described with reference to FIG. FIG. 4 is a diagram showing the relationship between the amount of movement of the objective lens 2 in the tracking direction and the drive voltage of the traverse motor 6, where the horizontal axis represents time and the vertical axes represent the amount of movement of the objective lens 2 in the tracking direction and the traverse motor 6 respectively. The voltage applied to the disk 10 is shown (however, the amount of eccentricity of the disk 10 is not shown).

The difference from the first embodiment is that an initial offset is added to the applied voltage of the traverse motor 6 as well.

As described above, according to the third embodiment, the initial offset of the objective lens 2 is generated by the objective lens actuator 3, and the applied voltage is also applied to the traverse motor 6 so that the objective lens is adjusted. It is possible to further reduce the offset amount of 2, and it is possible to realize high performance and high speed access of the disk playing device.

[0039]

As described above, according to the present invention, by driving the objective lens while offsetting it, it is possible to double the access speed with the same feeding accuracy of the optical head feeding device as the conventional one. . In addition, even if the access speed is the same, it is possible to improve the feed accuracy up to about 2 times, and the information recording / reproducing performance is greatly improved, so that the optical head feeder can be accessed at high speed, with high accuracy, and downsizing. realizable.

[Brief description of drawings]

FIG. 1A is an exploded perspective view of an optical head feeding means for a disk playing device according to a first embodiment of the present invention. FIG. 1B is an optical head feeding means for a disk playing device according to a first embodiment of the present invention. The figure which shows the relationship between the moving amount of the objective lens in the tracking direction and the drive voltage of the traverse motor.

FIG. 2 is a schematic view of an optical head feeding means for a disk playing device according to a first embodiment of the present invention.

FIG. 3 is a schematic diagram of an objective lens actuator of an optical head feeding means for a disk playing device according to a first embodiment of the present invention.

FIG. 4 is a diagram showing the relationship between the amount of movement of the objective lens in the tracking direction and the drive voltage of the traverse motor in the optical head feeding means for the disk playing device in the third embodiment of the present invention.

FIG. 5 is an exploded perspective view of an optical head feeding means for a disk playing device in a conventional embodiment.

FIG. 6 is a schematic view of an optical head feeding means for a disk playing device in a conventional embodiment.

FIG. 7 is a schematic view of an objective lens actuator of an optical head feeding means for a disk playing device in a conventional example.

FIG. 8 is a diagram showing a relationship between an amount of movement of an objective lens in a tracking direction and a drive voltage of a traverse motor in an optical head feeding device for a disk playing device in a conventional example.

[Explanation of symbols]

 1 Optical Head 2 Objective Lens 3 Objective Lens Actuator 4 Spindle 5 Sub-axis 6 Traverse Motor 7 Reduction Gear 8 Lead Screw 9 Feed Nut 10 Disc 11 Spindle Motor 12 Traverse Base 13 Turntable 14 Centering Ring 15 Motor Mounting Plate

Front page continuation (72) Inventor ▲ Taka ▼ Makoto Shima 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (8)

[Claims] 1. An objective lens, an objective lens actuator that drives the objective lens in a focus direction and a tracking direction, an optical head on which the objective lens actuator is mounted, and an optical head that moves the optical head in a radial direction of a disk. A disk playing device comprising: a feeding means, wherein the objective lens is initially offset in the tracking direction by the objective lens actuator and the optical head is fed and driven by the optical head feeding means. 2. The disc playing device according to claim 1, wherein an initial offset amount of the objective lens actuator in the tracking direction of the objective lens is set to approximately half the resolution of the optical head feeding means. 3. The disk playing device according to claim 1, wherein an initial offset is added to the voltage applied to the optical head feeding means. 4. The disc playing apparatus according to claim 1, wherein the initial offset amount of the objective lens in the tracking direction of the objective lens actuator or the offset amount of the optical head feeding means is independently variable. 5. The disk playing device according to claim 1, wherein both the offset amount of the objective lens by the objective lens actuator and the initial offset amount of the voltage applied to the optical head feeding means are variable. 6. The disc playing device according to claim 1, wherein an initial offset amount in the tracking direction of the objective lens by the objective lens actuator is set so that the information recording / reproducing performance of the optical head is optimized. 7. The disc playing apparatus according to claim 1, wherein the offset amount of the optical head feeding means is set so that the information recording / reproducing performance of the optical head is optimized. 8. The initial offset amount in the tracking direction of the objective lens by the objective lens actuator and the offset amount of the optical head feeding means are set so that the information recording / reproducing performance of the optical head is optimized. 1 or the disc playing device according to claim 6.