JPH11134695A - Optical information recording/reproducing head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the rigidity of a coarse adjustable arm and to make a semiconductor laser and collimator lens adjustable for the coarse adjustable arm by a simple constitution. SOLUTION: A mounting through-hole 123 for directly force-fitting a semiconductor laser 18 is provided in a holder base 120, the semiconductor laser 18 is force-fitted into the mounting through-hole 123 from its one side and a collimator lens 20 is directly attached to the other opening face of the mounting through-hole 123. In mounting the holder base 120 on the inner side wall of a unit base 110, it is mounted from the outside of the side wall of the unit base 110 by a spring washer and a screw 201 through a loose hole 112 while the electrode of the semiconductor laser 18 is set free to the outside through a hole provided on the side wall and positional adjustment in the direction orthogonal to the optical axis is performed under the condition that the holder base 120 is in press-contact with the inner side wall by elastic force of the spring washer obtained by loosened screw.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording / reproducing head, and more particularly to an improvement in a mounting structure of a semiconductor laser and its collimating lens.

[0002]

Recently, the areal recording density is 1
Magneto-optical disk devices exceeding 0 Gbit / (inch) ² are being developed. In this apparatus, the incident angle of the laser beam with respect to the objective optical system provided at the distal end of the coarse movement arm that rotates, for example, in the direction intersecting the track of the magneto-optical disk is finely adjusted by a deflecting unit such as a galvanometer mirror.
It has been considered that fine movement tracking is accurately performed at a narrow track pitch level of, for example, 0.34 μm.
By the way, in such an apparatus, a semiconductor laser and a collimating lens for converting a divergent light beam emitted from the semiconductor laser into a parallel light beam must be attached to the coarse movement arm.
In this case, both are small and simple with respect to the arm,
Must be adjustable.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and the invention of claim 1 has a mounting through-hole for directly pressing a semiconductor laser into a holder base. The semiconductor laser is press-fitted into the mounting through-hole from one side thereof, and a collimating lens for directly converting a laser beam emitted from the semiconductor laser into a parallel beam is directly mounted on the other opening surface of the mounting through-hole. When the holder base is attached to the inner surface of the side wall of the unit base constituting the optical information recording / reproducing head, the unit base is released in a state where the electrodes of the semiconductor laser are released to the outside through holes provided in the side wall. Attached by a spring washer and a screw from the outside of the side wall of the spring through a stupid hole, by the elastic force of the spring washer obtained with the screw loosened Serial characterized in that to perform the position adjustment in the direction orthogonal to the optical axis of the holder base while pressed against the inner surface of the side wall.

[0004]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, near-field recording (NFR: near) has been proposed in response to a demand for an external storage device accompanying the recent advances in hardware and software related to a computer, particularly a demand for a large storage capacity. field recor
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. Objective lens 1 by rising mirror 31
The laser light flux 13 incident on 0 is converged by the refraction of the objective lens 10. A solid immersion lens (SIL) 11 is disposed near the light-collecting point.
The convergent light is applied 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 configuration for mounting a laser diode as the semiconductor laser 18 (hereinafter simply referred to as the semiconductor laser 18) will be described. FIG. 6 is a diagram illustrating a mounting portion of the semiconductor laser 18. The semiconductor laser 18 and the collimating lens 20 share a common holder base 1.
The holder base 120 is attached to the unit base 110 which is a part of the outer peripheral wall of the rotating arm 3. The holder base 120 includes a plate-shaped portion 121 attached to the unit base 110 and a plate-shaped portion 1.
A substantially central portion 21 is a cylindrical portion 122 for holding the semiconductor laser 18 and the collimating lens 20.

Near the outer periphery of the collimating lens 20, an end face 20b orthogonal to the optical axis of the collimating lens 20 is formed. The collimating lens 20 is fixed by adhesion between the end surface 20b and the end surface (adhesion surface 125) of the tip of the cylindrical portion 122. The semiconductor laser 18 is press-fitted and fixed in a press-fitting hole 123 of a cylindrical portion 122.

As shown in FIG. 7, the semiconductor laser unit 100 and the collimating lens 20 are attached to the holder base 120 in advance, and the semiconductor laser unit 100 as one unit is fixed to the unit base 110 from inside. A screw hole 129 into which a screw 201 for fixing the holder base 120 is screwed is formed in the plate-like member 121 of the holder base 120.
Is formed with a through hole 112 for allowing the screw 201 to pass therethrough. The unit base 110 has an insertion hole 1 through which the lead 18a of the semiconductor laser 18 is inserted.
11 are formed.

Therefore, the plate member 121 is applied from the inside of the unit base 110, and the screw 201 is inserted from the outside of the unit base 110 (through the through hole 112) into the screw hole 129.
By screwing the holder base 120 into the unit base 110, the holder base 120 can be fixed to the unit base 110. The lead 18a of the semiconductor laser 18 is drawn out of the unit base 110 through the insertion hole 111, and outside the unit base 110,
A circuit board (not shown) and a shield member are attached. In addition, 202 and 203 are washers and washers.

In this embodiment, since the holder base is attached from the inside of the unit base, a large opening (sufficient enough to penetrate the holder base) is formed in the unit base as in the type in which the holder base is attached from the outside of the unit base. Need not be provided. Therefore, the rigidity of the rotating arm can be increased.

Next, an adjustment / fixing process before the semiconductor laser unit is assembled into the unit base will be described. 8 and 9 show a laser diode unit 10.
It is sectional drawing which shows the adjustment and fixing process of zero. First, as shown in FIG. 8, in the step of press-fitting the semiconductor laser 18 into the holder base 120, the semiconductor laser 18 is press-fitted into the press-fit hole 123 of the holder base 120 fixed to the work holding portion 150. The press-fit of the semiconductor laser 18
This is performed by a press-fitting member 155 which is a plunger.

The collimating lens 20 includes a lens holder 16
It is held by 0. At the time of press-fitting of the semiconductor laser 18, the light beam emitted from the collimator lens 20 temporarily fixed by the lens holding part 13 is
While pressing, the press-fitting member 155 is pushed in little by little. Then, when it is confirmed that the light beam emitted from the collimating lens 20 is parallel light, the press-fitting operation is completed.
Thereby, the position of the semiconductor laser 18 in the direction of the emission optical axis is determined.

Subsequently, the collimating lens 20 is bonded and fixed in the step shown in FIG. An adhesive is applied to the bonding surface 125 of the collimating lens 122 in advance. The holding unit 160 that holds the collimating lens 20 is configured such that the optical axis direction of the collimating lens 20 is perpendicular to the mounting reference surface 126 of the plate-shaped portion 121 of the holder base 120.
The collimating lens 20 is urged against the adhesive surface 125 of the holder base 120.

In this state, the position of the lens holder 160 is adjusted by an adjustment mechanism (not shown), and the light beam observation camera 140 checks the emission direction of the light emitted from the collimator lens 20. Then, when the perpendicularity of the emitted light from the collimating lens 20 to the mounting reference plane 126 falls within the allowable range, the UV irradiation device 165 is turned on to cure the adhesive, and the bonding operation of the collimating lens 20 is completed. I do.

[0026]

As described above, according to the optical information recording / reproducing head of the present invention, the rigidity of the coarse movement arm can be increased, and the semiconductor laser and the collimating lens can be moved with a simple structure to the coarse movement arm. Can be made adjustable.

[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 cross-sectional view showing a mounting portion of a semiconductor laser and a collimating lens.

FIG. 7 is an exploded view showing a mounting portion of FIG. 6;

FIG. 8 is a cross-sectional view showing an adjustment process of the laser diode unit.

FIG. 9 is a sectional view showing a laser diode unit fixing process.

[Explanation of symbols]

 Reference Signs List 18 semiconductor laser 20 collimating lens 100 semiconductor laser unit 110 unit base 120 holder base 121 plate-like part 122 cylindrical part 123 press-fit hole 125 adhesive surface 126 mounting reference surface 150 pressing member 160 lens holding member 165 UV irradiation device

Claims (1)

[Claims] An attachment through-hole for directly press-fitting a semiconductor laser into a holder base, the semiconductor laser is press-fitted into one of the through-holes, and the other through-hole of the attachment through-hole is provided in the other through-hole. When directly attaching a collimating lens for converting a laser beam emitted from the semiconductor laser into a parallel beam, and attaching this holder base to an inner surface of a side wall of a unit base constituting an optical information recording and reproducing head, An electrode is attached to the outside of the side wall of the unit base with a spring washer and a screw through a stupid hole in a state where the electrode is released outside through a hole provided in the side wall, and the spring washer obtained in a state where the screw is loosened is obtained. The position adjustment in the direction perpendicular to the optical axis is performed while the holder base is pressed against the inner surface of the side wall by elastic force. The optical information recording and reproducing head, wherein the door.