JPH06203388A - Fixing device for photodetector and optical head equipped with this fixing device - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention does not shift the photodetector when fixing the photodetector, and the position adjustment in the optical axis direction of the photodetector and in the direction orthogonal to the optical axis direction is performed. Provided is an optical head which can be operated only by moving a detector. The present invention is directed to an optical beam R reflected from an optical disk.
An optical base 21 having a photodetector 24 for receiving the light
A first surface 32 is formed on the optical base 21 via an adhesive 33.
And a fixing member 31, 31 for fixing the photodetector 24 via an adhesive 35 to a second surface 34 that is fixed to the first surface 32 and is orthogonal to the first surface 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head used in an optical disk device or the like, and more particularly to the mounting structure of its photodetector.

[0002]

2. Description of the Related Art An optical disk device, for example, as shown in FIG. 13, outputs a laser beam R emitted from a semiconductor laser (light irradiator) 1 through a collimator lens 2 and a beam splitter 3 (information disk). To the photodetector mechanism 8 through the beam splitters 3, 5, the converging lens 6 and the cylindrical lens 7 to reproduce the information recorded on the optical disc. Or detecting the relative positional deviation amount between the light beam and the optical disk. In the figure, 19 is a light quantity detector for detecting the quantity of light emitted from the semiconductor laser 1, and 20 is a tracking detector.

The photodetector mechanism 8 includes a photodetector 9 for converting the reflected light into an electric signal and a photodetector holder 10 for fixing the photodetector 9, and The detector holder 10 is the optical base 1 of the optical disk device.
It is adapted to be fixed to 1 by push screws 12, 12.

Further, in the photodetector mechanism 8, the direction along the surface of the photodetector holder 10 is set to be orthogonal to the optical axis direction of the light beam incident on the photodetector 9. Then, when adjusting the position of the photodetector 9,
By shifting the photodetector holder 10 in a state where the photodetector holder 10 is not completely fixed, the biaxial directions of the photodetector 9 are adjusted in the plane orthogonal to the optical axis direction. Further, by moving the converging lens 6 for converging the light beam in the optical axis direction, adjustment in the optical axis direction is performed so as to focus on an appropriate position.

[0005]

However, in the prior art, since the photodetector holder 10 was fastened and fixed by the push screws 12 and 12, when the photodetector holder 10 was fastened, it was not possible to make a small amount in the direction orthogonal to the optical axis of the converging lens 6. However, the position of the spot on the photodetector 9 is displaced due to the displacement of the photodetector holder 10. For this reason, it is necessary to readjust the deviation of the photodetector holder 10, resulting in a hindrance to the adjustment work.

In addition to adjusting the position of the photodetector 9, the converging lens 6 is moved in the optical axis direction to adjust the spot in the optical axis direction.

Therefore, according to the present invention, the photodetector is not displaced when the photodetector is fixed, and the photodetector is moved by adjusting the position of the reflected light in the optical axis direction and the direction orthogonal to the optical axis direction. An object of the present invention is to provide a fixing device for a photodetector that can be performed only by itself and an optical head including the fixing device.

[0008]

In order to solve the above problems, the present invention provides an optical base having a photodetector for receiving an optical beam reflected from an information recording medium, and the optical base.
And a fixing member for fixing the photodetector via an adhesive to a second surface that is continuous to the first surface in a non-parallel state with the first surface via an adhesive, Further, the optical base, a light irradiator attached to the optical base and irradiating a light beam, and the light beam radiated from the light irradiator are guided to an information recording medium, and the information is recorded. An optical system for guiding the light beam reflected from the recording medium in a predetermined direction, a photodetector for receiving the light beam reflected from the information recording medium and guided by the optical system, and the optical base. And a fixing member for fixing the photodetector via an adhesive to a second surface continuous in a non-parallel state to the first surface with an adhesive.

[0009]

With the above structure, the position of the photodetector in the three axial directions can be adjusted by moving the photodetector, and the photodetector is fixed with an adhesive. As a result, it is possible to prevent the occurrence of displacement during fixing.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in FIGS. FIG. 2 shows an optical head of an optical disk device.

This optical head is provided with an optical base 21 made of an aluminum material, and a semiconductor laser 22 as a light irradiator, an optical system 23 and a photodetector 24 are arranged on the optical base 21. is doing.

The optical system 23 includes a collimator lens 25,
The first and second beam splitters 26 and 31, the converging lens 27, and the cylindrical lens 28.

Further, the optical head 21 receives a part of the laser beam R emitted from the semiconductor laser 22 and detects a light amount thereof, and a photodetector 29 for light amount and a laser beam reflected from the optical disk. A tracking photodetector 30 for receiving a part of the beam R'is attached.

The laser beam R emitted from the semiconductor laser 22 is converted into parallel light by the collimator lens 25, transmitted through the first beam splitter 26, and guided to an optical disk (information storage medium) not shown.
The reflected light R ′ reflected from the optical disk is sent to the second beam splitter 31 via the first beam splitter 26, and transmitted from the second beam splitter 31 through the converging lens 27 and the cylindrical lens 28 to detect light. The light is received by the container 24. When the photodetector 24 receives the light, the reflected light is converted into an electric signal, and the information recorded on the optical disc is reproduced.

By the way, the photodetector 24 is shown in FIG.
As shown in FIGS. 1A and 1B, the optical base 21 is fixed by a pair of block-shaped fixing members 31 made of a glass material.

The pair of fixing members 31, 31 are the first
Surface 32 is fixed to the side surface portion of the optical base 21 via an adhesive (for example, High Speed Super 5 manufactured by Cemedine Co., Ltd.) 35.

The photodetector 24 includes the pair of fixing members 3
It is fixed to a second surface 34 that is continuous in a non-parallel state, that is, in a state of being orthogonal to the first surface 32 of 1, 1 with an adhesive (for example, High Speed Super 5 manufactured by Cemedine Co.) 33.

A flexible printed circuit board (not shown) is connected to the photodetector 24 through wirings 24a.
A signal from the photodetector 24 is taken out to this flexible printed board. Next, the positioning of the photodetector 24 and the fixing method thereof will be described.

First, the photodetector 24 is mounted on an adjusting jig (not shown), and the reflected light R'from the optical disk is made incident on the photodetector 24, and the output is observed as an electric signal to obtain a predetermined waveform. As described above, the photodetector 24 is moved in the three-axis directions by the adjusting jig, that is, in the optical axis direction and in the direction perpendicular to the two-axis directions.
Adjust the positioning by moving in parallel to the direction.

After this adjustment is completed, the adhesive 33, 33 is applied to both side surfaces of the photodetector 24 while the photodetector 24 is held by the adjusting jig, and the optical base 2 is used.
Adhesives 35, 35 are applied to the side surface portion of 1.

After that, the adhesive 3 of the optical base 21
The first surface 32 of the fixing member 31 is adhered to 5, 35, and the second surface 34 of the fixing member 31 is adhered to the adhesive 33, 33 of the photodetector 24. In this way, the adhesive 33,3
When 3, 35, 35 are solidified, the adjusting device is removed from the photodetector 24. 3A and 3B show a state in which the reflected light R'is displaced upward from the designed mounting center of the photodetector 24. FIGS. 4A and 4B show a state in which the reflected light R ′ is deviated downward from the designed mounting center of the photodetector 24. 5A and 5B show a state in which the reflected light R ′ is deviated to the right from the designed mounting center of the photodetector 24. FIGS. 6A and 6B show a state in which the reflected light R ′ is displaced to the left from the designed mounting center of the photodetector 24.

As can be seen from FIGS. 3 to 6,
If the reflected light R'is within a certain design allowable range, it is possible to adjust the photodetector 24 in the three axial directions and fix it to the optical base 21.

Incidentally, in the conventional adjustment work of the photodetector, the deviation in the direction orthogonal to the optical axis direction is caused by the photodetector holder.
Since the shift of the optical axis direction by the movement of 10 is adjusted by the movement of the converging lens 6, it is a two-step process. Since the adjustment in the axial direction is completed, the number of steps can be reduced.

Further, since the adjusting jig is not removed until the curing of the adhesives 33 and 35 is completed, the spot will not be displaced from the position at the time of completion of the adjustment, and the readjustment becomes unnecessary. Further, conventionally, the surface of the photodetector holder 10 and the optical base are
Since the surface of the cloth 11 is in direct contact with each other, it is necessary to reduce the surface roughness of both contact surfaces. According to the present embodiment, since there are no members that rub against each other during adjustment, the optical base 21
It is not always necessary to reduce the surface roughness of the. It should be noted that the present invention is not limited to the above-mentioned one embodiment, and may be as shown in FIG. That is, in this embodiment, the optical detector 21 is fixed via the fixing members 45, 45 with a part of the photodetector 24 inserted in the groove 41.

When the triaxial adjustment of the photodetector 24 is completed by the same method as in the above-mentioned embodiment, the adhesives 43, 43 are applied to both sides of the front side of the photodetector 24, and the optical base 21 is applied. Adhesives 44, 44 are applied to the inner wall surface of the groove 41.

Then, the first surfaces 4 of the fixing members 45, 45
6 is the adhesive 43, 43 on both sides on the front side of the photodetector 24.
Then, the second surfaces 47 of the fixing members 45, 45 are pressed against the adhesives 44, 44 on the inner wall surface of the groove 41 of the optical base 21. After the adhesives 43, 43, 44, 44 are hardened, the photodetector 24 is removed from the adjusting jig.

In the case of this embodiment, the width dimension of the groove 41 of the optical base 21 through which the reflected light R'passes must be increased, but the projection of the photodetector 24 from the end face of the optical base 21. There is an advantage that the amount can be reduced. 8 (a),
FIG. 8B shows a state in which the reflected light R ′ is displaced upward from the designed mounting center of the photodetector 24. Figure 9
9A and 9B show a state in which the reflected light R'is shifted downward from the designed mounting center of the photodetector 24. In FIG. 10A and FIG. 10B, the reflected light R ′ is the photodetector 24.
Shows the state of being shifted to the right from the designed mounting center. 11A and 11B show a state in which the reflected light R'is displaced to the left from the designed mounting center of the photodetector 24.

As can be seen from FIGS. 8 to 11, if the reflected light R'is within a certain design allowable range,
It is possible to adjust the photodetector 24 in three axial directions and fix it to the optical base 21.

As described above, the joint surface between the optical base 21 and the fixing members 31, 31, 42, 42 and the photodetector 24.
And the joint surfaces of the fixing members 31, 31, 42, 42 intersect, and the reflected light R ′ is within a certain design allowable range, no matter how the three axes are adjusted, Fixed member 3
The optical detector 24 is provided with an optical base via 1, 31, 42 and 42.
Since it can be bonded to the optical fiber 21, the bonding surface of the photodetector 24 can be taken in several ways, and combinations can be made according to the actual configuration of the optical head and the like.

Further, the fixing members 31, 42 are formed of a transparent material such as optical glass or polycarbonate resin, and a photo-curable adhesive is used as the adhesive 33, 35, 43, 44. May be. In this case, the photodetector 2
When the adjustment of 4 is completed, a predetermined light is irradiated by an irradiation device (not shown) to cure the adhesives 33 and 35.

Conventionally, the screws were carefully tightened over time so that the photodetector 24 would not be displaced, but according to this method, the light irradiation time is short, for example, 2 to 3 minutes. This leads to a reduction in man-hours.

The area of the joint surface of the photodetector 24 and the joint surface of the optical base 21 are more than a certain area.
If flatness is ensured, an anaerobic adhesive can be used as the adhesive.

That is, when the adjustment of the photodetector 24 in the three axial directions is completed, an anaerobic adhesive is applied to the joint surface of the photodetector 24 and the joint surface of the optical base 21 to fix the fixing member 3.
By pressing 1, 31 against the anaerobic adhesive, the air supply is cut off and the curing reaction proceeds. The curing of the anaerobic adhesive is completed in about several minutes, and the photodetector 24 can be removed from the adjusting jig. According to this, since a light source for photocuring is not required, the facility cost can be reduced, and since the light irradiation time is eliminated, the number of steps can be reduced.

In the above embodiment, the fixing member 3
Although the first surface 34 and the second surface 32 of FIG. 1 are orthogonal to each other, the present invention is not limited to this, and as shown in FIG. 12, the first surface 34 of the fixing member 31 may be tapered. Alternatively, the side surface of the photodetector 24 may be formed in a taper shape corresponding to the taper surface.

Further, in the above embodiment, the fixing member 3
Although both sides of the photodetector 24 are fixed by 1, 31, 45, 45, the present invention is not limited to this, and the fixing member 3
1, 31, 45, 45 are arranged above and below, and by these fixing members 31, 31, 45, 45, above the photodetector 24,
You may make it fix a lower part.

[0036]

As described above, the present invention provides an optical base provided with a photodetector for receiving an optical beam reflected from an optical information recording medium, and an adhesive to the optical base. And a fixing member for fixing the photodetector via an adhesive to the second surface continuous with the first surface in a non-parallel state to the first surface. It is possible to improve the assembling workability, reduce the manufacturing cost, and further improve the reliability, because there is no deviation and the position adjustment is unnecessary.

Further, by moving the photodetector, the position can be adjusted in the optical axis direction and the direction orthogonal to this optical axis direction, and it is not necessary to move the converging lens as in the conventional case, and the adjustment work is easy. become.

[Brief description of drawings]

1A and 1B show a mounting structure of a photodetector according to an embodiment of the present invention, FIG. 1A being a sectional view thereof and FIG. 1B being a side view thereof.

FIG. 2 is a configuration diagram showing an optical head to which the photodetector of FIG. 1 is attached.

3A and 3B show a state in which reflected light is displaced upward from a mounting center of the photodetector in FIG. 1, FIG. 3A being a plan view thereof, and FIG. 3B being a side view thereof.

4A and 4B show a state in which reflected light deviates downward from the mounting center of the photodetector in FIG. 1, FIG. 4A is a plan view thereof, and FIG. 4B is a side view thereof.

5A and 5B show a state in which reflected light is displaced to the left from the mounting center of the photodetector of FIG. 1, FIG. 5A being a plan view thereof, and FIG. 5B being a side view thereof.

6A and 6B show a state in which reflected light deviates to the right from the mounting center of the photodetector of FIG. 1, FIG. 6A being a plan view thereof, and FIG. 6B being a side view thereof.

7A and 7B show a photodetector mounting structure according to another embodiment of the present invention, FIG. 7A being a sectional view thereof, and FIG. 7B being a side view thereof.

8A and 8B show a state in which reflected light deviates upward from the mounting center of the photodetector of FIG. 7, FIG. 8A being a plan view thereof, and FIG. 8B being a side view thereof.

9A and 9B show a state in which reflected light deviates downward from the mounting center of the photodetector of FIG. 7, FIG. 9A being a plan view thereof, and FIG. 9B being a side view thereof.

10A and 10B show a state in which reflected light is shifted to the left from the mounting center of the photodetector in FIG. 7, FIG. 10A being a plan view thereof, and FIG. 10B being a side view.

11A and 11B show a state in which reflected light is shifted to the right from the mounting center of the photodetector in FIG. 7, FIG. 11A being a plan view thereof, and FIG. 11B being a side view thereof.

FIG. 12 is a sectional view showing a mounting structure for a photodetector that is another embodiment of the present invention.

FIG. 13 is a configuration diagram showing a conventional optical head.

[Explanation of symbols]

21 ... Optical base, 22 ... Light irradiator, R '... Reflected light, 2
3 ... Optical system, 24 ... Photodetector, 21 ... Optical base, 3
3, 35, 43, 44 ... Adhesive agent, 32, 46 ... First surface, 34, 47 ... Second surface, 31, 45 ... Fixing member.

Claims (2)

[Claims] 1. An optical base having a photodetector for receiving an optical beam reflected from an information recording medium, and a first surface fixed to the optical base via an adhesive. 1. A fixing device for a photodetector, comprising: a fixing member that fixes the photodetector to a second surface that is continuous with the first surface in a non-parallel state with an adhesive. 2. An optical base, a light irradiator attached to the optical base to irradiate a light beam, and a light beam radiated from the light irradiator to an information recording medium. , A light beam reflected from the information recording medium
An optical system for guiding a beam in a predetermined direction; a photodetector for receiving an optical beam reflected from the information recording medium and guided by the optical system; and a first optical system via an adhesive to the optical base. An optical head, comprising: a fixing member that fixes the photodetector via an adhesive to a second surface whose surface is fixed and is continuous in a non-parallel state to the first surface.