JP2000285555A - Optical disk drive - Google Patents

Abstract

(57) [Summary] [Problem] An optical disk device with a disk rotation frequency of 100
When the rotation speed is higher than Hz, the pressure distribution of the air generated by the rotation of the disk becomes large, and the disk vibration caused by the distribution becomes large. Due to the disk vibration, recording and reproduction cannot be accurately performed by the optical pickup, or the disk is damaged when the vibration is particularly large. In order to solve the above-mentioned problem, in addition to an opening into which an optical pickup for recording or reproducing information is inserted, a disk transfer member is separated from a center of rotation of the disk by at least 75% of a radius of the disk. It is assumed that the optical disk device has one or more holes, projections, or depressions provided at positions at 2% or more of the projected area of the disk.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk apparatus for reading out information from at least a recording medium on which information is optically recorded, and more particularly to reducing vibration when a disk as an information recording medium is rotated at a high speed. Optical disk device.

[0002]

2. Description of the Related Art An optical disk drive is a type of CD that rotates a disk as an information recording medium, irradiates the disk with a laser beam from an optical pickup, and records or reproduces information.
And MO and DVD devices. An optical disk device is characterized in that a disk can be exchanged. For this reason, it is common to have a loading mechanism for inserting or ejecting a disk from the apparatus, and a disk transfer member for transferring the disk. The configuration of the optical disk device is disclosed in, for example, Japanese Patent Laid-Open No. 9-17082. According to this, a cover is provided to cover the disk from the top surface to the side surface, and the disk is covered by a tray serving as a disk transfer member and the cover.

[0003]

The optical disk device is required to have a higher data transfer speed. For this reason, the speed of the disk rotation has been increased, and an optical disk device having a disk rotation frequency exceeding 100 Hz is being studied. At such a high speed rotation, the pressure distribution of air generated by the rotation of the disk becomes large, and the vibration of the disk caused by the distribution becomes large.
If the vibration of the disk increases, the information recorded on the disk cannot be accurately reproduced by the optical pickup, the information cannot be accurately recorded on the disk, or the disk may be damaged if the vibration is particularly large. Occurs.

[0004] However, in the above-mentioned conventional optical disk device, this problem has not been sufficiently considered. SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the present invention to provide an optical disk apparatus that can accurately record and reproduce information while suppressing vibration of the disk even when the disk is rotated at high speed.

[0005]

In order to achieve the above object, a disk transfer member for mounting a disk and transferring the disk into or out of the apparatus is provided, and the disk transfer member has a disk transfer member on a surface on which the disk is mounted. In addition to the opening into which the optical pickup for recording or reproducing information is inserted, at least 75% of the radius of the disk from the center of rotation of the disk, the projected area of the disk is 2% or more. An optical disk device provided with one or more holes, protrusions, or depressions.

[0006]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the optical disk apparatus of the present invention.

The operation of the optical disk apparatus is as follows. A disk transfer member 2 for transferring the disk 1 is projected from the front of the apparatus by a loading mechanism (not shown) for inserting or discharging the disk 1 as an information recording medium into or from the apparatus. The disk 1 is placed on the disk transfer member 2, and the disk 1 is stored in the apparatus by a loading mechanism. When the disk 1 is stored in the apparatus, the unit mechanism 5 including the spindle motor 3 and the optical pickup 4 is raised, and the disk 1 is mounted on a turntable 6 fixed to the axis of the spindle motor 3. The disk 1 mounted on the turntable 6 is pressed and fixed by a disk cover member 7 or a disk clamper 9 attached to a disk clamper holding member 8 provided on the apparatus.

In this manner, the disk 1 fixed to the spindle motor 3 is rotated at a predetermined rotation speed by the spindle motor 3, and at least the information recorded on the disk 1 is reproduced by the optical pickup 4. The optical pickup 4 can also record information on the disk 1.

Next, a description will be given of the flow of air generated by the rotation of the disk 1 and the vibration of the disk 1 caused by the rotation of the disk 1 in the optical disk apparatus having the above-described configuration.

FIG. 2 shows the flow of air generated by the rotation of the disk 1. FIG. 2A shows the flow of air on the upper surface of the disk 1 as a top view, and FIG.
Shows a cross-sectional view around the disk 1.

On the lower surface of the disk 1, air is sucked from the gap between the spindle motor 3 and the disk transfer member 2 and from the opening of the disk transfer member 2 into which the optical pickup 4 is inserted, and the centrifugal force generated by the rotation of the disk 1 Air flows from the inner circumference to the outer circumference of the disk 1 due to the force.
A part thereof flows out from the disk transfer member 2 and a part flows into the upper surface of the disk 1 as described later.

On the other hand, on the upper surface of the disk 1, the disk 1
Near the upper surface of the disk 1, air flows from the inner circumference to the outer circumference of the disk 1 due to centrifugal force caused by the rotation of the disk 1, and a part of the air flows out of the disk transfer member 2 and a part of the air leaves the upper surface of the disk 1 At the position, the disc 1 circulates from the outer circumference to the inner circumference. The pressure drops on the upper surface of the disk 1 due to air flowing out from the disk transfer member 2. To compensate for this, air flows from the lower surface of the disk 1 to the upper surface, and air flows from the outer circumference to the inner circumference of the disk 1. Therefore, on the upper surface of the disk 1, a flow of air from the inner circumference to the outer circumference and a flow of air from the outer circumference to the inner circumference of the disk 1 are repeatedly generated in the circumferential direction of the disk 1. Thus, a pressure distribution having a gradient from the inner circumference to the outer circumference of the disk 1 and a pressure distribution having a gradient from the outer circumference to the inner circumference of the disk 1 are repeatedly generated in the circumferential direction of the disk 1.

Since the disk 1 is an elastic body made of polycarbonate or the like, it has a unique vibration mode. FIG. 3 shows an example of the vibration mode. FIG. 3 shows a vibration mode calculated by the finite element method using a disc made of polycarbonate as a model having a diameter of 120 mm, a center hole diameter of 15 mm, and a plate thickness of 1.2 mm.

As shown in FIG. 3A, a vibration mode in which a peak and a valley of vibration appear twice in the circumferential direction of the disk 1 is about 100.
Hz, and the vibration mode in which the peaks and valleys of the vibration appear three times in the circumferential direction of the disk 1 as shown in FIG.
Hz.

By the way, as shown in FIG. 2, the pressure distribution caused by the air flow from the inner circumference to the outer circumference of the disk 1 and the air flow from the outer circumference to the inner circumference of the disk 1 repeatedly generated in the circumferential direction of the disk 1. Represents a disk 1 in which peaks and valleys of vibration repeat in the circumferential direction of the disk 1 as shown in FIG.
Will be strongly excited. As a result, the disk 1 is greatly deformed, and the optical pickup 4 cannot follow the disk deformation. If the deformation is further increased, the disc 1 may be damaged in some cases. This phenomenon is due to the pressure distribution due to the flow of air,
This occurs remarkably when the vibration modes of the disk 1 match. For this reason, it becomes particularly large when the rotation speed is high such that the rotation frequency exceeds 100 Hz. In the present invention, the air flow is changed so that the vibration mode of the disk 1 is not excited by the air flow.

The embodiment shown in FIG.
On the surface on which the disc 1 is mounted, one or more holes 11 are provided in addition to the opening into which the optical pickup 4 is inserted. FIG. 1 shows a case where there is one hole 11. As a result, air flows in and out between the opening provided in the disc transfer member 2 into which the optical pickup 4 is inserted and the newly provided hole 11, and the air flowing into the upper surface of the disc 1 is released. Therefore, the disk vibration can be reduced. The number of the holes 11 is not limited to one as long as it has an action of changing the air flow, and a plurality of holes 11 may be provided.

A hole 11 provided in the disk transfer member 2 is provided.
Is not limited to the surface on which the disk 1 is mounted, and the same effect can be obtained by providing the position on the surface covering the outer peripheral portion of the disk 1.

FIG. 4 shows a change in the vibration acceleration of the disk surface when the area of the hole 11 is changed while keeping the rotation speed constant. The figure shows the case where the positions of the holes are provided at 60% and 75% of the disk radius.

As shown in FIG. 4, when the position of the hole 11 provided in the disk transfer member 2 is at a position which is at least 75% of the radius of the disk 1 from the center of rotation of the disk 1, the effect of reducing disk vibration is large. In addition, when the area of the hole 11 provided in the disk transfer member 2 becomes 2% or more of the projected area of the disk 1, the effect of reducing the disk vibration becomes particularly large. For example, if the radius of the disc 1 is 60 mm,
A hole having an area of 220 mm ² or more is preferably provided at a position 45 mm or more from the rotation center of the disk 1. In addition, hole 1
1 with an optical pickup 4
When it is provided on the side opposite to the opening in which is inserted, it is particularly effective in reducing disk vibration.

Since increasing the area of the hole 11 is the same as eliminating the disk transfer member 2, the same effect of reducing disk vibration can be obtained by separating the disk 1 and the disk transfer member 2 by a certain distance or more. Is obtained. By setting the distance between the disk 1 and the disk transfer member 2 at least 2.5 times the thickness of the disk 1, a particularly large effect of reducing disk vibration can be obtained. For example, when the thickness of the disk 1 is 1.2 mm, the distance between the disk 1 and the disk transfer member 2 may be 3 mm or more.

Further, in this embodiment, one or more projections 12 are provided on the disk cover member 7 which covers the upper surface of the disk 1. FIG. 1 shows a case where the number of the protrusions 12 is two.
In FIG. 1, the disk cover member 7 also serves as a cover for covering the upper part of the apparatus. Around the protrusion 12 provided on the disk cover member 7, the flow of air changes, and the pressure distribution also changes. In particular, when there are a plurality of protrusions 12, the effect of making the pressure distribution different from the vibration mode of the disk 1 shown in FIG. 3 is increased, so that disk vibration can be reduced. Further, the means for changing the flow of air is not limited to the protrusion, and a depression may be provided.

Further, in this embodiment, the disk clamper holding member 8 is also provided with one or more projections 13. FIG.
Has shown the case where the number of the protrusions 13 is two. The projection 13 provided on the disk clamper holding member 8 has the same effect as the projection 12 provided on the disk cover member 7. Further, the means for changing the flow of air is not limited to the protrusion, and a depression may be provided.

Incidentally, in FIG.
1 is provided, a projection 12 is provided on the disk cover member 7, and a projection 13 is provided on the disk clamper holding member 8. However, any one of the hole and the projection has an effect of reducing the disk vibration. Therefore, any one of the configuration in which the hole 11 is provided in the disk transfer member 2, the configuration in which the projection 12 is provided in the disk cover member 7, and the configuration in which the projection 13 is provided in the disk clamper holding member 8 may be implemented.

Next, another embodiment of the present invention is shown in FIG. In the embodiment shown in FIG. 5, one or more projections 21 are provided on the surface of the disk transfer member 2 on which the disk 1 is placed. FIG. 5 shows a case where the number of the protrusions 21 is five.

The air flow from the inner circumference to the outer circumference of the disk 1 changes around the projection 21 thus provided,
The pressure distribution also changes. In particular, when there are a plurality of projections 21, the effect of making the pressure distribution different from the vibration mode of the disk 1 shown in FIG. 3 is increased, so that disk vibration can be reduced. The position of the protrusion 21 provided on the disk transfer member 2 is not limited to the surface on which the disk 1 is placed as shown in FIG. 5A, but may be a surface covering the outer peripheral portion of the disk 1 as shown in FIG. The same effect can be obtained by providing the same. In addition, the means for changing the flow of air is not limited to protrusions,
A depression may be provided.

Next, another embodiment of the present invention is shown in FIG.

The embodiment shown in FIG.
The distance between the surface on which the disk is mounted and the disk 1 decreases from the center of the disk 1 toward the outer periphery.
The surface of the disk transfer member 2 on which the disk 1 is mounted is tapered. This makes it difficult for air to flow from the inner circumference to the outer circumference of the disk 1, and suppresses air flowing from the lower surface to the upper surface of the disk 1. Therefore, the excitation force in the vibration mode of the disk 1 shown in FIG. 3 can be reduced.

Next, another embodiment of the present invention is shown in FIG.

The embodiment shown in FIG.
Is provided with one or more projections 31. FIG. 7 shows a case where the number of the protrusions 31 is two. By providing the protrusions 31 on the disk clamper 9 in this manner, the air flow when the disk 1 rotates is changed, and the air flow as shown in FIG. 2 does not constantly occur. Therefore, the excitation force of the disk 1 in the vibration mode can be reduced. At this time, when the distance L from the outer peripheral portion of the disk clamper 9 to the tip of the projection 31 is 15% or more of the radius of the disk 1, a large effect of reducing disk vibration can be obtained. For example, when the radius of the disk 1 is 60 mm, the distance L from the outer periphery of the disk clamper 9 to the tip of the projection 31 may be set to 9 mm or more. Further, as shown in FIG. 8, one or more depressions 32 are provided in the disc clamper 9, or
By providing more than one slit 33, the same effect as above can be obtained.

Next, another embodiment of the present invention is shown in FIG.

In the embodiment shown in FIG. 9, the disc clamper 9 is configured such that the distance r from the center of rotation of the disc 1 to the contact portion between the disc clamper 9 and the disc 1 is 35% or more of the radius of the disc 1. Things. With this configuration, disk vibration when the disk rotation frequency is 100 Hz or higher can be greatly reduced. For example, when the radius of the disk 1 is 60 mm, the distance r between the disk clamper 9 and the contact portion of the disk 1 may be set to 21 mm or more. It should be noted that the contact portion between the disk clamper 9 and the disk 1 is at a distance of 35
The shape of the disk clamper 9 is not limited to a circle but may be an ellipse or a polygon.

Next, another embodiment of the present invention is shown in FIG.
In the embodiment shown in FIG. 10, one or more projections 41 are provided on the turntable 6 of the spindle motor 3 on which the disk 1 is mounted and rotated. FIG. 10 shows a case where the number of the protrusions 41 is two.

By providing the projections 41 on the turntable 6 in this manner, the flow of air when the disk 1 rotates is changed, and the flow of air as shown in FIG. 2 does not constantly occur. Therefore, the excitation force in the vibration mode of the disk 1 shown in FIG. 3 can be reduced.

[0035]

As described above, according to the present invention, it is possible to prevent the pressure distribution due to the flow of air, which is generated when the disk rotates at high speed, from being matched with the vibration mode of the disk. Therefore, even when the disk is rotated at high speed, it is possible to provide an optical disk apparatus capable of accurately recording and reproducing information while suppressing the vibration of the disk.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of an optical disk device of the present invention.

FIG. 2 is a diagram showing a flow of air accompanying rotation of a disk.

FIG. 3 is a diagram showing a vibration mode of a disk.

FIG. 4 is a diagram showing an effect of the embodiment of the optical disk device of the present invention.

FIG. 5 is a diagram showing another embodiment of the optical disk device of the present invention.

FIG. 6 is a diagram showing another embodiment of the optical disk device of the present invention.

FIG. 7 is a diagram showing another embodiment of the optical disk device of the present invention.

FIG. 8 is a diagram showing another embodiment of the optical disk device of the present invention.

FIG. 9 is a diagram showing another embodiment of the optical disk device of the present invention.

FIG. 10 is a diagram showing another embodiment of the optical disk device of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Disc, 2 ... Disc transfer member, 3 ... Spindle motor, 4 ... Optical pickup, 5 ... Unit mechanism, 6 ...
Turntable, 7: disk cover member, 8: disk clamper holding member, 9: disk clamper, 11: hole,
12 ... projection, 13 ... projection, 21 ... projection, 31 ... projection, 3
2 ... depression, 33 ... slit, 41 ... projection.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yoshiaki Yamauchi 502 Kandachicho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratories, Hitachi, Ltd. (72) Seiichi Kato 502-Kindachi-cho, Tsuchiura-shi, Ibaraki Hitachi, Ltd. Inside the Machinery Research Laboratory (72) Inventor Hayato Shimizu 502 Kandachi-cho, Tsuchiura-shi, Ibaraki Inside Machinery Research Laboratory, Hitachi Ltd. (72) Mitsuo Satake 1st Kitano, Makino, Mizusawa-shi, Iwate Inside Hitachi Media Electronics Co., Ltd. (72) Inventor Masayoshi Watanabe 1 Kitano, Majo, Mizusawa-shi, Iwate Prefecture Inside Hitachi Media Electronics Co., Ltd. (72) Inventor Hideo Suenaga 1-Kitano Masaki, Mizusawa-shi, Iwate Prefecture Hitachi Media Electronics Co., Ltd. (72) Invention Person Shinya Iizaka 1 Kitano, Majo, Mijosawa-shi, Iwate Stock Exchange Hitachi Media Electronics in the F-term (reference) 5D090 AA01 CC04 CC16 DD03 DD05 EE11 FF21 LL07

Claims (10)

[Claims] 1. An optical disk device for reproducing at least information by rotating a disk as an information recording medium, comprising: a disk transfer member for mounting and transferring the disk, wherein the disk of the disk transfer member is mounted. At least 75% of the radius of the disk from the center of rotation of the disk, and at least 2% of the projected area of the disk. An optical disc device provided with one or more holes, protrusions, or depressions. 2. An optical disk device for reproducing at least information by rotating a disk as an information recording medium, comprising a disk transfer member for mounting and transferring the disk, wherein the disk of the disk transfer member is mounted. An optical disc device, wherein one or more holes, protrusions, or depressions are provided in an outer peripheral portion of the optical disc device. 3. An optical disk device for rotating a disk, which is an information recording medium, to reproduce at least information, comprising a disk transfer member for mounting and transferring the disk, wherein the disk of the disk transfer member is mounted. An optical disk device characterized in that a surface of the disk is inclined so as to increase from the center of the disk toward the outer periphery. 4. An optical disk apparatus for reproducing at least information by rotating a disk as an information recording medium, comprising: a disk transfer member for mounting and transferring the disk, wherein the disk is rotated by a spindle motor for rotating the disk. An optical disk device, wherein, after being mounted, a distance between the surface of the disk transfer member on which the disk is mounted and the disk is at least 2.5 times the thickness of the disk. 5. An optical disk device for reproducing at least information by rotating a disk as an information recording medium, comprising: a disk cover member for covering the disk, wherein the disk cover member has 2% of a projected area of the disk. An optical disc device comprising one or more projections or depressions as described above. 6. An optical disk device for rotating a disk as an information recording medium and reproducing at least information, comprising: a disk clamper for pressing and fixing the disk against a turntable of a spindle motor for rotating the disk; An optical disc device, wherein one or more protrusions, dents, or slits are provided on an outer peripheral portion of a disc clamper. 7. The optical disk device according to claim 6, wherein
An optical disk device, wherein a distance from an outer peripheral portion of the disk clamper to a tip of the protrusion is 15% or more of a radius of the disk. 8. An optical disc apparatus for reproducing at least information by rotating a disc as an information recording medium at a rotation frequency of 100 Hz or more, wherein the disc is fixed by pressing the disc against a turntable of a spindle motor for rotating the disc. An optical disk device comprising a clamper, wherein a contact portion between the disk clamper and the disk is located at a position at least 35% of a radius of the disk from a rotation center of the disk. 9. An optical disk apparatus for reproducing at least information by rotating a disk as an information recording medium, comprising: a disk clamper for pressing and fixing the disk to a turntable of a spindle motor for rotating the disk. 2% of the projected area of the disk is provided on the disk clamper holding member for holding the disk clamper.
An optical disc device comprising one or more projections or depressions as described above. 10. An optical disc apparatus for rotating a disc, which is an information recording medium, to reproduce at least information, wherein at least one projection is provided on an outer peripheral portion of a turntable of a spindle motor for rotating the disc. Optical disk device.