JPH11126355A - Arm structure of optical information recording / reproducing head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the manufacturing cost of an arm of an optical information recording head and reproducing head. SOLUTION: In the optical information recording and reproducing head by which a luminous flux emitted from a laser light source is made to be a parallel light flux, then is guided in the direction parallel with an optical disk via a deflecting means and the laser light flux is deflected in the direction orthogonal to the optical disk by a deflecting mirror just before being made incident on an objective optical system and then focused on the optical disk through the objective optical system, both end faces parallel with the optical disk at the top end part of the arm where the deflecting mirror 31 is arranged are provided with openings 351, 352 respectively capable of emitting laser light fluxes on the laser disk.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arm structure of an optical information recording / reproducing head, and more particularly, to an arm structure suitable for a head for performing fine movement tracking of an optical disk by deflecting a laser beam.

[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. By the way, when performing recording / reproduction on both sides of one magneto-optical disk, two coarse movement arms are naturally required. In such a case, a dedicated arm must be prepared for each, and there is a problem that the cost is increased.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and the invention of claim 1 is to convert a light beam emitted from a laser light source into a parallel light beam and then deflect the light beam. Optical information recording / reproducing in which a laser beam is deflected by a deflecting mirror in a direction orthogonal to the optical disk immediately before being guided into a direction parallel to the optical disk via the means and incident on the objective optical system, and then condensed on the optical disk by the objective optical system The head is characterized in that openings capable of emitting a laser beam are provided on both end surfaces of the arm on which the deflection mirror is provided, at both ends parallel to the optical disk.

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. The rotary arm 3 is rotatable around a rotary 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. Further, a light source module 7 having a light source unit and a light receiving unit is disposed near the rotation shaft 5 of the rotation arm 3, and is configured to be driven integrally with the rotation 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 tip end in a direction in which it 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,
The rotation arm 17 is rotatably fastened to the drive arm 17 by applying an electric current to the drive coil, so that 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, the structure of the above-described rotating arm 3 will be described. FIG. 6 is a side sectional view of the rotating arm. In order to perform recording and reproduction on both sides of the optical disk 2, one rotating arm 3 is provided above and below the optical disk 2. The configuration of the two rotating arms 3 is the same except for the mounting position of the rising mirror 31 and the floating optical unit 6, and each of the rotating arms 3 has the optical system shown in FIG.

The upper rotating arm 3 is provided with a flexure beam 8 and a floating optical unit 6 below the distal end, whereas the lower rotating arm 3 is provided with a flexure beam 8 above the distal end. And a floating optical unit 6. In addition, the rising mirror 31 of the upper rotating arm 3
Are arranged so as to reflect the laser beam 13 downward, whereas the rising mirror 31 of the lower rotating arm 3 is disposed.
Are arranged to reflect the laser beam upward.

The two rotating arms 3 are supported by a cylindrical portion 50 which is rotatably supported around a rotating shaft 5. The rotating shaft 5 and the cylindrical portion 50 are rotatably fastened by a bearing 17, and the two rotating arms 3 are respectively held on pedestals 51 provided at a predetermined interval in the axial direction of the cylindrical portion 50. Have been. The above-described drive coil 16 for driving the voice coil motor 4 is attached to the cylindrical portion 50. Therefore, when a current is applied to the drive coil 16, the two rotating arms 3 rotate integrally by the electromagnetic action with the magnetic circuit M.

The upper and lower surfaces 301,
In 302, openings 351 and 352 located above and below the rising mirror 31 are formed. The laser beam reflected by the rising mirror 31 on the upper rotating arm 3 reaches the floating optical unit 6 via the opening 352 in the lower surface 302. On the other hand, the laser beam reflected by the rising mirror 31 of the lower rotating arm 3 is reflected on the upper surface 301.
To the floating optical unit 6 through the opening 351 of the optical disk.

With such a configuration, the upper and lower rotating arms 3 can be shared except for the arrangement of the rising mirror 31, the flexure 8, and the floating optical unit 6. That is, it is not necessary to prepare a dedicated rotation arm for each, and the manufacturing cost can be reduced.

[0022]

As described above, according to the arm structure of the optical information recording / reproducing head of the present invention, the two coarse movement arms for performing recording / reproduction on both sides of one magneto-optical disk are almost common. Can be Therefore, it is not necessary to prepare a dedicated rotation arm for each, and the manufacturing cost can be reduced.

[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.

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

FIG. 4 is a plan view showing a deflection mirror and a floating optical unit.

FIG. 5 is a side sectional view of a rotating arm.

FIG. 6 is a diagram showing a mounting structure of a deflecting mirror.

[Explanation of symbols]

 2 Optical Disk 3 Rotating Arm 5 Rotating Axis 6 Floating Optical Unit 8 Flexure 31 Deflection Mirror 301 Upper Surface (of Rotating Arm) 302 Lower Surface (of Rotating Arm) 351, 352 Opening

Claims (1)

[Claims] After a light beam emitted from a laser light source is converted into a parallel light beam, the light beam is guided in a direction parallel to the optical disk via a deflecting means, and is deflected in a direction orthogonal to the optical disk immediately before being incident on an objective optical system. An optical information recording / reproducing head which is deflected by a mirror and then condensed on an optical disk by the objective optical system, and can emit laser light beams to both end surfaces parallel to the optical disk at a tip end of an arm provided with the deflection mirror. Arm structure of the optical information recording / reproducing head, characterized by having a simple opening.