JPH11126352A - Rotating structure for galvanomirror - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an arm for coarse motion light in weight and to miniaturize it by attaching a deflection mirror with a thin plate part whose thickness is sufficiently thinner than the thickness of a supporting part which is formed by being connected to the end part of the logitudinal direction of the supporting part having a presecribed plate thickness and a height and a length and which achieves a function as a hinge part to make the mirror turnable about the thin plate part. SOLUTION: A turning supporting member 110 is constituted in a T shape when it is seen from the vertical upper side and is constituted of a base part 111 and prolonged part 112 which is prolonged to the vertical direction from the base part 111. The prolonged part 112 has a prescribed width W and a height H and a constricted hinge part 113 whose width is cut thin is formed in the vicinity of its top end. Moreover, a top end part 114 having the width W is formed at a more end part than the hinge part 113. The top end part 114 is bent around the hinge part 113 by the elastic deformation of the hinge. Thus, a mirror holder, a deflection mirror and a coil fixed to the top end part 114 turn around the hinge part 113.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating structure of a galvanometer mirror, and more particularly to a rotating structure suitable for a small-sized galvanometer mirror used for fine movement tracking of an optical information recording / reproducing apparatus.

[0002]

Recently, the areal recording density is 1
Magneto-optical disk devices exceeding 0 Gbit / (inch) ² are being developed. In this apparatus, the angle of incidence of a laser beam on an objective optical system provided at the tip of a coarse movement arm that rotates, for example, in a direction intersecting the track of the magneto-optical disk is finely adjusted by a deflecting means such as a galvo mirror, and the fine movement is performed. It is considered that tracking is accurately performed at a narrow track pitch level of, for example, 0.34 μm. In this case, the conventional structure in which the mirror is supported by a spring or a rotating shaft cannot not only satisfy the demand for the lightweight and compact size of the coarse movement arm, but also improves the mechanical frequency characteristics. There was a need for improvement.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and a first aspect of the present invention is to provide a support having a predetermined thickness, height, and length. A thin plate portion, which functions as a hinge portion and is formed at the longitudinal end of the support portion and is sufficiently thinner than the plate thickness continuously formed on the support portion, and deflects through the thin plate portion. A mirror is attached so that the deflecting mirror can be rotated about the height direction of the thin plate portion as an axis.

BEST MODE FOR CARRYING OUT THE INVENTION

[0004] First, a demand has been proposed for an external storage device, particularly a demand for a large storage capacity, in accordance with the recent advances in hardware and software related to computers.
Field recording (NFR: near field recording)
An outline of a magneto-optical disk recording / reproducing apparatus using a recording / reproducing method called a technique will be described with reference to FIGS.

FIG. 1 is an overall schematic diagram of the optical disk device. An optical disk 2 is mounted on a rotating shaft of a spindle motor (not shown) in the disk drive device 1. On the other hand, a rotating (coarse movement) arm 3 for reproducing or recording information on the optical disk 2 is mounted so as to be parallel to the recording surface of the optical disk 2. This rotating arm 3
Is rotatable about a rotation shaft 5 by a voice coil motor 4. A floating optical head 6 having an optical element mounted thereon is mounted on a tip of the rotating arm 3 facing the optical disk 2. In addition, the rotating arm 3
A light source module 7 having a light source unit and a light receiving unit is disposed in the vicinity of the rotation shaft 5 and is configured to be driven integrally with the rotating arm 3.

FIGS. 2 and 3 illustrate the distal end portion of the rotating arm 3, and particularly illustrate the floating optical head 6 in detail. The floating optical unit 6 is attached to the flexure beam 8 and is arranged to face the optical disc 2. The flexure beam 8 is fixed to the rotating arm 3 at the other end, and presses the floating optical unit 6 at the distal end portion in a direction in which the floating optical unit 6 comes into contact with the optical disc 2 by the elastic force of the flexure beam 8.

The floating optical unit 6 includes a floating slider 9, an objective lens 10, and a solid immersion lens (S
IL) 11 and a magnetic coil 12, and functions to converge a parallel laser beam 13 emitted from the light source module 7 onto the optical disc 2. A rising mirror 31 is fixed to the tip of the rotating arm 3 to guide the laser beam 13 to the floating optical unit 6. The objective lens 10 is provided by the rising mirror 31.
Is converged by the refraction of the objective lens 10. A solid immersion lens (SIL) 11 is arranged in the vicinity of the converging point, and irradiates the convergent light to the optical disc 2 as finer evanescent light 15.

A magnetic coil 12 for recording in a magneto-optical recording system is formed around a solid immersion lens (SIL) 11 facing the optical disk 2. It can be applied on the surface. This evanescent light 1
5 and the magnetic coil 12 enable high-density recording and reproduction on the optical disk 2. The floating optical unit 6 floats by a very small amount due to the airflow generated by the rotation of the optical disk 2 and follows the surface runout of the optical disk 2. For this reason, focus control (focus servo) of the objective lens, which is required in the conventional optical disk device, is not required.

The light source module 7 mounted on the rotating arm 3 and the light beam guided to the floating optical unit 6 will be described in detail below with reference to FIGS. The rotating arm 3 has a floating type optical unit 6 mounted at the tip and a driving coil 1 for driving a voice coil motor 4 at the other end.
6 is fixed. The drive coil 16 is a flat coil, and is inserted and arranged in a magnetic circuit (not shown) with a gap. The rotating shaft 5 and the rotating arm 3 are provided with a bearing 17,
When the current is applied to the drive coil, the rotation arm 3 can be rotated about the rotation shaft 5 by the electromagnetic action with the magnetic circuit.

The light source module 7 mounted on the rotating arm 3 has a semiconductor laser 18, a laser drive circuit 19,
Collimating lens 20, composite prism assay 21, laser power monitor sensor 22, reflection prism 2
3, a data detection sensor 24 and a tracking detection sensor 25 are arranged. The laser beam in a divergent beam state emitted from the semiconductor laser 18 is converted into a parallel beam by the collimating lens 20. The cross-sectional shape of the parallel light beam is an elliptical shape due to the characteristics of the semiconductor laser 18, and it is inconvenient to narrow the light beam onto the optical disk 2 minutely. Therefore, the cross-sectional shape of the parallel light beam is shaped by making the parallel light beam having an elliptical cross section emitted from the collimating lens 20 enter the composite prism assay 21.

The entrance surface 21a of the composite prism assay 21
Has a predetermined slope with respect to the incident optical axis. By refracting the incident light, the cross-sectional shape of the parallel light beam can be shaped from an oval shape to a substantially circular shape. The shaped laser beam travels through the complex prism assay 21 and enters the first half mirror surface 21b. The first half mirror surface 21b transmits information obtained from the optical disk 2 to the data detection sensor 24 and the tracking detection sensor 25.
However, on the outward path, it serves to separate the light beam to the laser power monitor sensor 22 for detecting the output power of the laser emitted from the semiconductor laser 18.

Since the laser power monitor sensor 22 outputs a current proportional to the intensity of the received light, the output of the semiconductor laser 18 can be stabilized by feeding back this output to a laser power control circuit (not shown). . The laser beam 13 having a substantially circular cross-sectional shape and emitted from the composite prism assay 21 is applied to the deflecting mirror 26, and the traveling direction of the laser beam 13 is changed. The deflecting mirror 26 is attached to a galvano motor 27 having a rotation center about an axis perpendicular to the plane of the paper, and can deflect the laser beam 13 by a small angle in a direction parallel to the plane of the paper.

The galvano motor 27 is provided with a deflection mirror position detection sensor 28 for detecting the rotation angle of the deflection mirror 26. The laser beam 13 reflected by the deflecting mirror 26 is transmitted to the first relay lens 29 and the second relay lens 29.
After passing through a relay lens (imaging lens) 30, the light is reflected by a rising mirror 31 and reaches the floating optical unit 6. The first relay lens 29 and the second relay lens 30 make the relationship between the reflection surface of the deflecting mirror 26 and the pupil surface (principal plane) of the objective lens 10 arranged in the floating optical unit 6 into a conjugate relationship. That is, a relay lens optical system is formed. That is, when the condensed beam on the optical disk 2 is slightly deviated from a predetermined track, the deflecting mirror 26 is slightly rotated to tilt the laser beam 13 incident on the objective lens 10 to move the focal point on the optical disk 2. Correction. However, when performing focus correction with this method,
If the optical distance between the deflecting mirror 26 and the objective lens 10 is long, the amount of movement of the laser beam 13 incident on the objective lens 10 increases, and it may not be possible to enter the objective lens 10.

In order to avoid such a phenomenon, the first relay lens 29 and the second relay lens 30
The relationship between the reflection surface of the deflecting mirror 26 and the pupil surface of the objective lens 10 is set to be a conjugate relationship, and even if the deflecting mirror 26 rotates, the laser beam 13 incident on the objective lens 10 does not move, Tracking control is made possible. The access operation over the inner circumference / outer circumference of the optical disk 2 is performed by rotating the rotating arm 3 by the voice coil motor 4, and only minute tracking control is performed by rotating the deflection mirror 26.

The return laser beam 13 reflected from the optical disk 2 and returning returns to the deflecting mirror 2 in a direction opposite to the forward path.
The reflected light is incident on the composite prism assay 21.
Thereafter, the light is reflected by the first half mirror surface 21b and travels to the second half mirror surface 21c. The second half mirror surface 21c generates transmitted light directed to the tracking detection sensor 25 and reflected light directed to the data detection sensor 24, and separates the laser beam on the return path. The laser beam transmitted through the second half mirror surface 21c is applied to the tracking detection sensor 25, and outputs a tracking error signal.

On the other hand, the laser beam reflected by the second half mirror surface 21c is polarized and separated by the Wollaston prism 32, converted into convergent light by the condensing lens 33, and then reflected by the reflecting prism 23 to be detected by the data detection sensor. 24. The data detection sensor 24 has two light receiving areas, and receives two polarized beams polarized and separated by the Wollaston prism 32 to read data information recorded on the optical disk 2 and output a data signal. To be precise, the tracking error signal and the data signal are generated by a head amplifier circuit (not shown) and sent to a control circuit or an information processing circuit.

Next, a structure for rotatably supporting the deflecting mirror 26 in the galvano motor 27 will be described. FIG. 6 is a perspective view showing the galvano motor 27. As described above, the deflection mirror 26 of the galvano motor 27 rotates around a predetermined rotation axis (referred to as Z). The galvano motor 27 includes a mirror holder 100 that holds the deflecting mirror 26 and a rotation support member 1 that supports the mirror holder 100 so as to be rotatable about a rotation axis Z.
10 is provided.

The mirror holder 100 is a barrel-shaped block, and its central axis (X axis) is orthogonal to the rotation axis Z. In FIG. 6, an axis orthogonal to both the X axis and the rotation axis Z is defined as a Y axis. The deflecting mirror 26 has a mirror holder 100 such that its mirror surface 26a is orthogonal to the Y axis.
Attached to. Further, coils 121 and 122 are held at both ends of the mirror holder 100 in the X-axis direction, respectively. The coils 121 and 122 have a pair of magnets 12.
5, 126 are opposed to each other, and the coils 121, 12
When a current flows through the mirror holder 1, the electromagnetic induction between the coils 121 and 122 and the magnets 125 and 126 causes the mirror holder 1 to operate.
00 rotates around the rotation axis Z. Thereby, the direction of the laser beam reflected by the deflection mirror 26 can be changed.

FIGS. 7 and 8 are a sectional view taken along the line AA 'and a sectional view taken along the line BB' of the galvano motor 27 shown in FIG. 7 and 8, the magnets 125, 126
Is omitted. The rotation support member 110 is used for the mirror holder 10.
0 is provided on the side opposite to the deflection mirror 26. The rotation support member 110 is formed in a T-shape when viewed from vertically above, and includes a base portion 111 arranged in parallel with the mirror holder 100 and a support portion 112 extending from the base portion 111 in the Y-axis direction. I have. FIG. 9 is a perspective view showing the rotation support member 110. Rotation support member 110
Has a predetermined width W and a predetermined height H, and a hinge portion 113 having a narrow width is formed in the vicinity of the distal end thereof. Further, the hinge portion 113 of the support portion 112
A tip portion 114 having a width W is further formed at the tip.

The mirror holder 100 has two concave portions 102 and 103 formed in the Y-axis direction, and the concave portion 102 and the concave portion 103 are separated by a wall 104. The above-described deflection mirror 26 is attached to one of the concave portions 102, and the support portion 112 of the rotation support member 110 is inserted into the other concave portion 103. Then, the distal end portion 114 of the support portion 112 of the rotation support member 110 is inserted into the U-shaped groove 104 a formed in the wall 104 of the mirror holder 100 so that the hinge portion 113 and the rotation axis Z coincide. It is fitted.

Due to the elastic deformation of the narrow hinge portion 113, the support portion 112 is bent around the hinge portion 113. Therefore, the mirror holder 100 to which the distal end 114 of the support 112 is fixed rotates around the hinge 113 (that is, the rotation axis Z). With such a configuration, the rotation support member 110 and the magnets 125 and 126
Is a fixed portion fixed to the rotating arm 3, and the mirror holder 100, the deflecting mirror 26, and the coils 121 and 122 are movable portions. The movable parts (mirror holder 100, deflection mirror 26,
The coils 121 and 122) rotate around the rotation axis Z.

When the mirror holder 100 rotates,
Due to the elastic restoring force of the hinge portion 113, the hinge portion 113
Are urged to return to the state where they have been extended in a straight line. Also,
As shown in FIG. 8, the rotation support member 110 is
6 is supported from behind, the rigidity of the deflection mirror 26 against external force F in the Y-axis direction is improved.

FIG. 10 is a perspective view showing a galvano motor according to the second embodiment. In the second embodiment, the support 1
In FIG. 12, an opening 213b is formed at the center in the height H direction of the narrowed portion (the narrowed portion 213). The ends of the constricted portion 213 located above and below the opening 213b are hinge portions 213a and 213a, respectively. That is, the deflection mirror is rotated by the elastic deformation of the hinge portions 213a, 213a. According to the second embodiment, since the elastic restoring force of the hinge portion is relatively weak, the deflection mirror can be rotated with a light driving force.

[0024]

As described above, according to the rotating structure of the galvanomirror of the present invention, the galvanomirror is rotatably supported with a small dimension in the direction of the rotating shaft, thereby reducing the weight and size of the coarse movement arm. It becomes possible to satisfy the request.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a basic configuration of a magneto-optical disk device according to an embodiment.

FIG. 2 is a diagram showing a distal end portion of a rotating arm of the magneto-optical disk device of FIG. 1;

FIG. 3 is a sectional view showing a floating optical unit.

FIG. 4 is a plan view showing a configuration of a rotating arm.

FIG. 5 is a side view of the rotating arm of FIG. 4;

FIG. 6 is a view showing a galvano motor.

FIG. 7 is a sectional view of the galvano motor of FIG. 6;

FIG. 8 is a cross-sectional view of the galvano motor of FIG.

FIG. 9 is a perspective view showing a rotation support member of the galvano motor of FIG. 6;

FIG. 10 is a perspective view illustrating a galvano motor according to a second embodiment.

[Explanation of symbols]

 26 Deflection mirror 100 Mirror holder 102, 103 Recess 104 Wall 110 Rotation support member 112 Extension 113 Hinge

Claims (1)

[Claims] A supporting portion having a predetermined thickness, height, and length, and a function as a hinge portion, wherein the thickness of the supporting portion is smaller than the thickness of the supporting portion provided at an end in a longitudinal direction of the supporting portion. A galvanomirror, comprising a thin plate portion that is sufficiently thin, and a deflecting mirror attached via the thin plate portion, so that the deflecting mirror can be rotated about the height direction of the thin plate portion as an axis. Rotating structure.