JP2927270B2 - Optical disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc device suitable for use in, for example, an optical recording / reproducing apparatus for recording / reproducing information on a recording medium.

[0002]

2. Description of the Related Art Generally, an optical disk device is provided with a lens holder for holding an objective lens for condensing light emitted from a light source on a recording medium. Conventionally, as a lens holder in this type of optical disk device, a lens holder elastically held by a plurality of wires in a device housing is employed. This will be described with reference to FIG. 6. In FIG. 6, a reference numeral 1 denotes a holding block that is housed in an apparatus housing (not shown) and is capable of moving back and forth in a tracking direction.
Reference numeral 2 denotes a lens holder that is elastically held by the four wires 3 on the holding block 1 and holds the light transmitter / receiver 4, the objective lens 5, and the like.

A focus coil 6 and a tracking coil 7 are mounted on the lens holder 2 so that the objective lens 5 follows the operation of a disk as a recording medium due to disturbance.

[0004] In the optical disk device thus configured, the light emitted from the laser light source of the optical transmitter / receiver 4 is 2
The light is bent by two reflecting mirrors (not shown), passes through the objective lens 5, and is focused on the disk. The light reflected by the disc returns to the light receiving element of the optical transmitter / receiver 4 via the same optical path as the optical path of the emitted light.

When the disk vibrates due to disturbance during recording / reproduction, the lens holder 2 rotates and moves in the focus direction and the tracking direction following this vibration operation.
Retreat.

In this type of optical disk drive, the lens holder 2 is connected to the holding block 1 by wires 3.
, The lens holder 2 is easily affected by inertia when vibrating. As a result, a stable operation of the objective lens 5 cannot be obtained, and time loss occurs at the time of high-speed access.

To prevent the occurrence of time loss at the time of high-speed access, a conventional optical disk device has been proposed which has a structure in which the lens holder 2 rotates and advances and retreats with respect to a fixed shaft.

[0008]

However, the conventional optical disk device has a structure in which a part of the fixed shaft, a part of the optical path from the light source to the recording medium, and the optical components face the lens holder 2. There has been a problem that the space inside the device housing becomes large and the entire device becomes large.

The present invention has been made in view of the above circumstances, and has as its object to provide an optical disk device that can reduce the space in the device housing and thereby reduce the size of the entire device. .

[0010]

According to a first aspect of the present invention, there is provided an optical disk drive which is housed and held in an apparatus housing, rotates in a sagittal plane, and advances and retreats in a meridional plane. And a fixed shaft that is inserted through the lens holder and that is disposed in the apparatus housing so as to cross the optical path from the light source to the recording medium and that extends in the focus direction. And a round bar shaft for light transmission that forms a part of the optical path.

According to a second aspect of the present invention, in the optical disk device of the first aspect, a square sleeve having an inner peripheral surface opposed to the outer peripheral surface of the fixed shaft with a predetermined gap is provided in the shaft insertion portion of the lens holder. The sleeve is mounted, and the refractive index of the sleeve is set to the same refractive index as that of the fixed shaft.

According to a third aspect of the present invention, in the optical disk device of the first aspect, the fixed shaft is formed by a shaft having a meniscus cross section by cutting out a part of the outer peripheral surface of the shaft.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings. FIG. 1 is a perspective view showing an optical system of an optical disc device according to a first embodiment of the present invention.
(A) and (B) are an optical path diagram showing an optical system of an optical disc device according to the first embodiment of the present invention and a perspective view showing a fixed shaft thereof, and FIG. 3 is an optical system according to the first embodiment of the present invention. FIG. 4 is a perspective view shown for explaining a holder operation direction of the disk device. In FIG. 1, the optical system of the optical recording / reproducing apparatus denoted by reference numeral 11 includes a lens holder 12, an optical transmitter / receiver 13, an objective lens 14, a reflection mirror 15, a fixed shaft 16, and a sleeve 17.

The lens holder 12 is formed entirely of a flat circular lens holder, and is housed and held in a device housing (not shown) by, for example, magnetic levitation by a floating mechanism (not shown). On the outer peripheral edge of the holder of the lens holder 12, there are mounted focus coils 18a and 18b arranged in parallel at equal intervals in the circumferential direction, and tracking coils 19a and 19b located near the focus coils 18a and 18b. The action of the coils 18 and 19 and the magnet 20 causes the lens holder 12 to rotate in the tracking direction m in the sagittal plane and in the focus direction n in the meridional plane.
To go back and forth.

A space 20 for forming an optical path a from the optical transmitter / receiver 13 to the disk D as a recording medium is formed in the lens holder 12, and a corner penetrating in the focus direction is formed at the center of the holder. A hole 21 is provided.

The light transmitter / receiver 13 includes a light emitting element and a light receiving element (both not shown), and is held in the lens holder 12 with a part thereof being exposed to the outside of the holder. The objective lens 14 is held in the lens holder 12 such that a part of the lens is exposed to the outside of the holder similarly to the optical transmitter / receiver 13. As a result, light emitted from a light emitting element (not shown) is focused on the disk D as a recording medium. The reflection mirror 15 is composed of two reflection mirrors 15a and 15b located below the light transmitter / receiver 13 and the objective lens 14, respectively.
It is stored in the lens holder 12.

The fixed shaft 16 is connected to the lens holder 12.
And is disposed so as to vertically cross the optical path a in an apparatus housing (not shown). The fixed shaft 16 is formed entirely of a round bar shaft extending in the focus direction and serving as a pivot of the lens holder 12, and entirely forms a part of the optical path a, such as optical glass or optical resin (PMMA). It is formed of a light transmitting material.

The sleeve 17 is a square sleeve having an inner peripheral surface facing the outer peripheral surface of the fixed shaft 16 with a predetermined minute gap.
1 is mounted with a part of the sleeve facing the space 20. The sleeve 17 is formed of a material having the same refractive index as the fixed shaft 16. Thus, aberrations generated when the emitted light passes through the fixed shaft 16 are reduced.

In FIG. 3, the sagittal surface is a surface extending in the tracking direction m and the jitter direction and perpendicular to the focus direction n, and the meridional surface is extended in the focus direction n and the jitter direction and extends in the sagittal surface. The plane is orthogonal.

In the optical recording / reproducing apparatus thus configured, the light emitted from the light emitting element (not shown) of the light transmitter / receiver 13 is reflected by the reflection mirror 15a, and then the sleeve 1
7, the light passes through the fixed shaft 16 and the sleeve 17 sequentially, is reflected by the reflection mirror 15b, and then passes through the objective lens 14 to reach the disk D. The light reflected by the disk D returns to the light receiving element (not shown) of the optical transceiver 13 via the same optical path a as the optical path a of the emitted light.

When the disk D vibrates due to disturbance during recording and reproduction, the lens holder 12 rotates in the tracking direction m in the sagittal plane following the vibration operation, and moves forward and backward in the focus direction n in the meridional plane.

Accordingly, in the present embodiment, a part of the storage space in the lens holder 12 can be shared, so that the space in the apparatus housing (not shown) can be reduced.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a perspective view showing an optical system of an optical disk device according to a second embodiment of the present invention, and FIGS. 5A and 5B are diagrams showing the optical disk device according to the second embodiment of the present invention. FIG. 4 is an optical path diagram showing an optical system including a fixed shaft in a meridional plane, in which the same members as those in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description is omitted. In the figure, the optical system of the optical recording / reproducing apparatus indicated by reference numeral 31
, An optical transmitter / receiver 13, an objective lens 14, a reflection mirror 15, and a fixed shaft 33.

The lens holder 32 is a lens holder having a plane circular shape as in the lens holder 12 of the first embodiment, and is provided in a housing (not shown) by a magnetic mechanism such as a floating mechanism (not shown). It is stored and held by floating. The lens holder 32 rotates in the tracking direction m in the sagittal plane and moves in the focus direction n in the meridional plane by the action of the focus coils 18a and 18b and the tracking coils 19a and 19b and the magnet 20. This is the same as the lens holder 12.

A space 20 for forming an optical path a is formed in the lens holder 32 in the same manner as the lens holder 12 of the first embodiment, and a circular hole 34 penetrating in the focus direction is formed in the center of the holder. Is provided.

The fixed shaft 33 is attached to the lens holder 32.
And is disposed so as to vertically cross the optical path a in an apparatus housing (not shown). The fixed shaft 33 extends in the focus direction as in the case of the fixed shaft 16 of the first embodiment, and is formed by cutting off a part of the outer peripheral surface of a round shaft used as a pivot of the lens holder 32. A shaft, that is, a meniscus cross section in which the thickness of the shaft (maximum radial dimension) is set to d, and the respective radii of curvature of the projections and the depressions are set to r ₁ and r ₂ (in the sagittal plane, one is a depression and the other is a projection) The whole is formed of a light transmitting material such as optical glass or optical resin (PMMA) which forms a part of the optical path a. The dimensions of the fixed shaft 33 are determined while adjusting the amount of aberration according to the optical components used in the optical system 31.

In the optical recording / reproducing apparatus configured as described above, the light emitted from the light emitting element (not shown) of the light transmitter / receiver 13 is reflected by the reflecting mirror 15a, then transmitted through the fixed shaft 33 and reflected. After being reflected by the mirror 15b, the light passes through the objective lens 14 and reaches the disk D. The light reflected by the disk D returns to the light receiving element (not shown) of the optical transceiver 13 via the same optical path a as the optical path a of the emitted light.

When the disk D vibrates due to a disturbance during recording and reproduction, the lens holder 32 rotates in the tracking direction m in the sagittal plane following the vibration operation, and moves forward and backward in the focus direction n in the meridional plane.

Therefore, in the present embodiment, a part of the storage space in the lens holder 32 can be shared, so that the space in the apparatus housing can be reduced.

In the present embodiment, an example in which the present invention is applied to an optical recording / reproducing apparatus has been described. However, the present invention is not limited to this, and it goes without saying that the present invention can be applied to other optical disk devices including an optical reproducing apparatus. It is.

[0031]

As described above, according to the present invention, a lens holder which is housed and held in an apparatus housing, rotates in a sagittal plane, and advances and retreats in a meridional plane, and is inserted through the lens holder and mounted in the apparatus housing. A fixed shaft disposed in the body so as to cross the optical path from the light source to the recording medium and extending in the focus direction.
Since it is composed of a light-transmitting round bar shaft that forms a part of the optical path as a pivot of the lens holder, a part of the storage space in the lens holder can be shared.

Therefore, the space in the device housing can be reduced, and the size of the entire device can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an optical system of an optical disc device according to a first embodiment of the present invention.

FIGS. 2A and 2B are an optical path diagram showing an optical system of the optical disc device according to the first embodiment of the present invention and a perspective view showing a fixed shaft thereof.

FIG. 3 is a perspective view for explaining a holder operation direction of the optical disc device according to the first embodiment of the present invention.

FIG. 4 is a perspective view showing an optical system of an optical disc device according to a second embodiment of the present invention.

FIGS. 5A and 5B are optical path diagrams showing optical systems each including a fixed shaft in a sagittal plane and a meridional plane in an optical disk device according to a second embodiment of the present invention.

FIG. 6 is a perspective view showing an optical system of a conventional optical disk device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Optical system 12 Lens holder 14 Objective lens 13 Optical transmitter / receiver 16 Fixed shaft 17 Sleeve m Tracking direction n Focusing direction

Claims (3)

(57) [Claims] A lens holder that is housed and held in an apparatus housing, rotates in a sagittal plane, and advances and retreats in a meridional plane; and a light source inserted into the lens holder and inserted into the apparatus housing from a light source. It is arranged to cross the optical path to the recording medium,
A fixed shaft extending in a focus direction, the fixed shaft being a pivot of the lens holder,
An optical disc device comprising a light-transmitting round bar shaft that forms a part of the optical path. 2. An angular sleeve having an inner peripheral surface opposed to an outer peripheral surface of the fixed shaft with a predetermined gap is mounted in a shaft insertion portion of the lens holder, and the refractive index of the sleeve is adjusted by the refractive index of the fixed shaft. 2. The optical disk device according to claim 1, wherein the refractive index is set to be the same as the refractive index. 3. The optical disk device according to claim 1, wherein the fixed shaft is formed by a shaft having a meniscus cross section by cutting out a part of an outer peripheral surface of the shaft.