JP3143404B2 - Optical head device and optical disk device - 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 head device used in an optical disk system, and more particularly to a structure of an optical deflection device used as a tracking actuator thereof.

[0002]

2. Description of the Related Art In an optical head device used in an optical disk system, there is a tracking servo actuator in which a high frequency band is separated into an optical deflection device (galvanometer mirror device) and a low frequency band is separated into a slide motor.

That is, an optical head device of this type has a fixed optical system constituted by an optical block containing a laser diode and a photodetector and a galvanomirror device as an optical deflecting device for reflecting and deflecting a light beam emitted from the optical block. A movable optical system including an objective lens that focuses the light beam reflected by the galvanomirror device on the recording surface of the disk and a slide motor that slides and feeds the objective lens in the radial direction of the disk, A band is limited to each actuator, that is, the galvanomirror device and the slide motor, and accurate and quick tracking operation is performed by cooperation of the galvanomirror device and the slide motor.

Attention is paid to a galvanomirror device used in the optical head device configured as described above. This galvanomirror device has a mirror for reflecting a light beam incident from an optical block toward an objective lens. When the mirror is angularly displaced in the direction perpendicular to the optical axis of the light beam by a tracking signal from the servo system, the light beam is deflected and fine tracking control is performed.

[0005]

Conventionally, such a galvano mirror device employs a configuration in which the mirror is supported by an elastic material so that the mirror can be angularly displaced in a direction perpendicular to the optical axis of the light beam. However, in this configuration, the elastic material easily bends downward due to the weight of the mirror, and the normal state of the mirror, that is, the initial state changes due to this bending deformation,
For example, the mirror is inclined so as to fall forward and downward.

Therefore, in this galvanomirror device, it is necessary to apply an initial force for holding the mirror in a predetermined initial state to the mechanism for controlling the angular displacement of the mirror, and the control for that purpose is complicated. In addition, due to the tilting of the mirror due to the bending of the elastic material described above, the angular displacement force required for the servo control for angularly displacing the mirror also becomes biased, and it is difficult to perform the control with high accuracy. Become.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and makes it possible to easily and precisely control the control by preventing the control from becoming complicated and reducing the control accuracy due to the weight of the mirror as described above. There are issues to be solved in order to be able to do so.

[0008]

SUMMARY OF THE INVENTION The present invention provides a laser diode, a photodetector, and an optical deflecting device arranged so that laser light emitted from the laser diode is incident from a horizontal direction parallel to the surface of a disk. A movable optical system having a fixed optical system comprising: an objective lens; driving means for driving the objective lens in the optical axis direction; and a deflecting element for directing laser light from the fixed optical system to the objective lens. And a mechanism for moving the movable optical system in the radial direction of the disk with respect to the fixed optical system, wherein the optical deflector is arranged to be wider in a direction perpendicular to the surface of the disk. A mirror that fixes and supports both ends of the leaf spring, and reflects laser light incident from a horizontal direction parallel to the disk surface toward the deflection element at the middle of the leaf spring. Mounting, which is constituted so as to angularly displace the mirror in a direction perpendicular to the plane containing the incident direction and the reflected direction of the laser beam. Further, the present invention provides a fixed optic having a laser diode, a photodetector, and an optical deflecting device arranged so that laser light emitted from the laser diode is incident from a horizontal direction parallel to a surface of a disk. A system, an objective lens, and driving means for driving the objective lens in the optical axis direction;
A movable optical system having a deflecting element for directing a laser beam from the fixed optical system to the objective lens, a mechanism for feeding the movable optical system to the fixed optical system in the radial direction of the disc, and a disc mounted and held horizontally. The optical deflector comprises: a rotary drive means for rotating and driving the optical disc; and the optical deflecting device fixedly supports both ends of a leaf spring disposed so as to be wide in a direction perpendicular to the surface of the disc. In the middle part of the spring,
A mirror that reflects the laser light incident from the horizontal direction parallel to the disk surface toward the deflecting element is attached, and the mirror is angularly displaced in a direction perpendicular to the plane including the incident direction and the reflection direction of the laser light. It is what was constituted. With the configuration described above, the leaf spring supporting the mirror is prevented from bending due to the weight of the mirror, the adjustment work for setting the mirror to a predetermined angular position is facilitated, and the angular displacement control of the mirror is performed. It will be easier.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a spindle motor, and 2 denotes a turntable attached to a drive shaft of the motor 1, on which an optical disk D is mounted and held. Reference numeral 3 denotes an optical head device for reading or writing signals from / to the disk D as a whole, and reference numeral 4 denotes a base on which the constituent members are mounted and fixed.

The optical head device 3 is roughly divided into a fixed optical system 5 and a movable optical system 6. First, the fixed optical system 5 includes an optical block 10 including a laser diode 7, a photodetector 8, a beam splitter 9, and the like.
And a galvanomirror device 11 as an optical deflection device that reflects and deflects the light beam (laser light) emitted from the optical block 10 to perform fine tracking. The configuration of the galvanomirror device 11 will be described later in detail.

On the other hand, the movable optical system 6 includes an objective lens 12 and
A slide block 14 having a prism 13 as a deflecting element for raising the optical axis L of the light beam reflected by the galvanomirror device 11 to the objective lens 12 is provided. The mechanism 15 is configured to slide in the radial direction of the disk D.

The objective lens feed mechanism 15 is configured as follows. That is, a guide rail 16 is fixed on the base 4 in parallel with the disk D, and a slide block 14 is supported movably along the guide rail 16. The slide block 14 is driven by a linear motor, that is, the linear motor includes a yoke 17 and a magnet 18 fixed to the base 4 side, and a coil 19 wound around the slide block 14.
At the time of reproduction (or recording) operation, a tracking signal is supplied to the coil 19 so that the slide block 1
4 is driven in the radial direction of the disk D along the guide rail 16, that is, the feeding operation of the objective lens 12 is performed. Reference numeral 20 denotes a focus coil for focusing the objective lens 12.

The optical head device 3 of this embodiment has the above-mentioned fixed optical system 5 and the objective lens feed mechanism 15 constituting the movable optical system 6 arranged on one plane. The optical block 10 is fixed to the base 4 in a horizontal state so that the light beam is emitted in a horizontal direction (a direction parallel to the disk D). The light beam emitted from the optical block 10 On the other hand, it is horizontally reflected by the galvanomirror device 11 arranged at 45 ° in a direction coinciding with the moving direction (feed axis) of the objective lens 12 and guided to the movable optical system 6, and further vertically by the prism 13 in the slide block 14. After being raised in the direction, the objective lens 12 forms a spot on the recording surface of the disk D.

That is, the optical axis L of the light beam emitted from the optical block 10 is developed on one plane parallel to the disk D, except for the rising part to the objective lens 12. Become. Therefore, in this case, the normal of the galvanomirror device 11 is the optical axis plane (the galvanomirror device 11).
Axis of the light beam incident on the mirror and the galvanomirror device 1
(A plane formed by the optical axis of the light beam reflected by 1).

FIGS. 2 to 5 show a detailed configuration of the galvanometer mirror device 11. Reference numeral 21 denotes a base of the galvanomirror device, and reference numeral 22 denotes a base that is rotatably supported on the base 21 via an adjustment mechanism described later. Support frame. A mirror support 23 is supported by the support frame 22 via a leaf spring 24 so as to be rotatable in the vertical direction, that is, in a direction perpendicular to the optical axis of the light beam. A mirror 25 for reflecting the light beam is provided. Here, as shown in FIG. 3, the leaf spring 24 is disposed in the horizontal direction so as to be wider in the direction perpendicular to the surface of the disk, and both left and right ends thereof are fixedly supported by the support frame 22. , This leaf spring 24
Has a structure in which a mirror support 23, that is, a mirror 25 is supported at an intermediate portion. A coil 26 is wound around the peripheral surface of the mirror support 23, while a magnet 27 is mounted on the support frame 22 side opposite to the coil 26 to form a galvano motor.

Further, the galvanomirror device 11
, An adjustment mechanism for adjusting the angular position of the mirror 25 is provided. This adjusting mechanism has the following configuration. The base 21 of the galvanomirror device 11 is
A support hole 28 formed in the front portion is fitted into a protrusion 29 protruding from the base 4, and the support hole 28 is in a direction transverse to the base 4 around the protrusion 29, that is, parallel to the optical axis plane of the light beam. It is rotatably supported in the direction (omega ₁ direction) such. Base 2
A long hole 30 (more precisely, an arc-shaped long hole centered on the protruding column 29) 30 is formed in the rear part of the base 1 and an adjusting screw 31 is inserted through the long hole 30 so that the tip of the adjustment screw 31 is connected to the base 4. Is screwed into a screw hole 32 formed in the hole. Then, by loosening the adjusting screw 31, the base 21 moves ω with respect to the base 4.
The mirror 21 can be rotated in _one direction, that is, the angle of the mirror 25 can be adjusted in a direction parallel to the optical axis of the light beam. After the adjustment is completed, the adjustment screw 31 is tightened to fix the base 21 at that position.

On the other hand, between the base 21 and the support frame 22, a roller 3 is provided between V-shaped grooves 33 and 34 formed to face each other.
5 is sandwiched, the support frame 22 is made tiltable in a vertical direction, i.e. the light beam of the optical axis plane and a direction perpendicular to the base 21 (omega ₂ direction) the roller 35 as a fulcrum. Further, a shaft-shaped pin 37 is inserted into a through hole 36 formed in the base 21 below the roller 35 (this pin 3
7 are provided on the left and right sides). One end of each of the pins 37 is fitted and fixed in a fixing hole 38 formed in the support frame body 22 in a press-fit manner, and a washer 39 is fitted on the other end. A compression coil spring 40 is fitted between the washer 39 and the base 21, and the support frame 22 is biased by the elastic biasing force of the compression coil spring 40 so that the support frame 22 is always tilted downward. Have been. An adjusting screw 42 is inserted into a through hole 41 formed in the base 21 above the roller 35, and a tip of the adjusting screw 42 is screwed into a screw hole 43 formed in the support frame 22. By rotating the screw 42, the support frame 22 is moved ω ₂ around the roller 35 with respect to the base 21.
The mirror 25 is tilted in the direction, that is, the angle of the mirror 25 is adjusted in the direction perpendicular to the optical axis plane of the light beam.

[0018] Thus each independently adjusting the angle of the mirror 25 in the omega ₁ direction and omega ₂ directions by manipulating the adjusting screw 31 and 42, the optical axis L of the light beam which is reflected by the mirror 25 It can be made to exactly coincide with the slide feed axis of the objective lens 12.

As described above, the galvanomirror device 11
With the angular position of the mirror adjusted, the tracking signal from the servo system is supplied to the coil 26 during the reproduction (or recording) operation, so that the mirror 25 moves in the vertical direction, that is, the direction perpendicular to the optical axis plane of the light beam. , Whereby the optical axis L of the light beam is deflected, and the position of the spot focused on the recording surface of the disk D moves in the radial direction of the disk, that is, fine tracking is performed.

In this galvanomirror device 11,
The leaf spring 24 is fixed to and supported by the support frame 22 at both ends so as to be wide in a direction perpendicular to the surface of the disk. Therefore, the optical head device is placed in a normal posture in which the disk D is horizontal as shown in the figure. In a state where the mirror 3 is arranged, the leaf spring 24 is prevented from bending downward due to the weight of the mirror 25. Therefore, while preventing the center position of the mirror 25 from being shifted,
The mirror 25 can be held upright, and the mirror 2
It is not necessary to apply an initial force for holding the mirror 25 in a vertical state to the drive mechanism that controls the angular displacement of the mirror 5. Further, the bias of the force when the mirror 25 is angularly displaced in the vertical direction by the servo operation is eliminated. This allows
Control of the angular displacement of the galvanometer mirror device 11 can be performed easily and with high accuracy.

Although the embodiment of the present invention has been described above, the present invention can adopt various embodiments without being limited to the configuration of this embodiment, and this embodiment specifies the present invention. Of course not.

[0022]

As described above, in the optical head device and the optical disk device according to the present invention, the optical deflecting device has a mirror at an intermediate portion of a leaf spring disposed so as to be wide in a direction perpendicular to the surface of the disk. Since the disk spring is supported, the plate spring is prevented from bending due to the weight of the mirror in a state where the apparatus of the present invention is arranged in a normal posture in which the disk is horizontal, and the adjustment work for installing the mirror at a predetermined angular position is performed. There is an effect that the mirror displacement can be easily controlled.

[Brief description of the drawings]

FIG. 1 is a perspective view of an optical head device according to the present invention.

FIG. 2 is a plan view of a galvanomirror device (optical deflecting device) used in the optical head device according to the present invention.

FIG. 3 is a front view of the same.

FIG. 4 is a perspective view of the same.

FIG. 5 is a vertical sectional side view of the same.

[Explanation of symbols]

3 optical head device, 5 fixed optical system, 6 movable optical system, 7 laser diode, 8 photodetector, 11 galvanometer mirror device (optical deflection device), 1
2 ‥‥ objective lens, 15 ‥‥ objective lens feed mechanism, 24
{Leaf spring, 25} mirror, D {disk, L}
Optical axis of light beam

Claims (2)

(57) [Claims] 1. A fixed optic comprising a laser diode, a photodetector, and an optical deflecting device arranged so that laser light emitted from the laser diode is incident from a horizontal direction parallel to a surface of a disk. A movable optical system having a system, an objective lens, driving means for driving the objective lens in the optical axis direction, and a deflecting element for directing laser light from the fixed optical system to the objective lens; A mechanism for feeding the movable optical system in the radial direction of the disk with respect to the system, wherein the light deflector is provided with both ends of a leaf spring disposed so as to be wider in a direction perpendicular to the surface of the disk. Fixedly supported, and a mirror for reflecting laser light incident from a horizontal direction parallel to the disk surface toward the deflection element is attached to an intermediate portion of the leaf spring, An optical head device wherein the mirror is angularly displaced in a direction perpendicular to a plane including the incident direction and the reflection direction of the laser light. 2. A fixed optic comprising a laser diode, a photodetector, and an optical deflecting device arranged so that laser light emitted from the laser diode is incident from a horizontal direction parallel to a surface of a disk. A movable optical system having a system, an objective lens, driving means for driving the objective lens in the optical axis direction, and a deflecting element for directing laser light from the fixed optical system to the objective lens; A mechanism for feeding the movable optical system in the radial direction of the disk with respect to the system, and rotation driving means for rotating the disk while placing and holding the disk horizontally, wherein the optical deflector is provided on the surface of the disk. Both ends of a leaf spring arranged so as to be wide in the vertical direction are fixedly supported, and are incident on an intermediate portion of the leaf spring from a horizontal direction parallel to the disk surface. An optical disk device comprising: a mirror for reflecting laser light toward the deflection element; and an angular displacement of the mirror in a direction perpendicular to a plane including an incident direction and a reflection direction of the laser light. .