JPH03230328A - Method for fixing photodiode substrate on pickup chassis - Google Patents

Abstract

PURPOSE:To make it unnecessary to shift the position of a photodiode or correct the positional shear of the photodiode by fixing a photodiode base on a pickup chassis by means of adhesive without using a screw for fastening. CONSTITUTION:The photodiode 8 is stuck to the photodiode substrate 21, anaerobic adhesive 22 is applied to the lower face of the substrate 21 and then the lower face of the substrate 21 is mounted on a prescribed position of the chassis 20. Then, the spatial position adjustment of the photodiode 8 is executed so that the spot of reflected light from the recording face of a CD arrives at the reference position of the photodiode 8. During the setting of the adhesives 22, the substrate 21 is optionally shifted to adjust the position of the photodiode 8. After completing the positional adjustment, the recessed part 20a of the chassis 20 with ultraviolet curing adhesive 23, the adhesive 23 is irradiated with ultraviolet rays to cure it. After the lapse of a prescribed time in that state, the adhesive 22 is set to firmly fix the substrate 21 on the pickup chassis 20.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a photodiode substrate that supports a photodiode used in an optical pickup in an optical disc player such as a CD (compact disc) player. The present invention relates to a method for attaching a photodiode substrate to a chassis, and particularly to a method for attaching a photodiode substrate to a pickup chassis, which prevents displacement of the photodiode and improves the work of attaching the photodiode substrate to the pickup chassis.

[Prior Art] FIG. 3 is a perspective view showing an optical pickup used in a CD player.

In Figure 3, numeral 1 is a laser diode that emits a laser beam, 2 is a diffraction grating for forming three spots, 3 is a flat mirror, 4 is a collimating lens for converting diverging light into parallel light, and 5 is total internal reflection. Mirror, 6 is optical disk D
7 is a plano-concave snub to which a plano-concave lens is attached to adjust the focal position of the return light from the optical disk D; 8 is a plano-concave lens for adjusting the focal position of the return light from the optical disk D; A photodiode for detection, 9 a photodiode substrate to which the photodiode 8 is fixed, and 10 a pickup chassis. Among the optical components arranged in these optical pickups, the photodiode 8 has its lead 8a soldered to the photodiode substrate 9 as shown in the cross-sectional view of FIG.
The photodiode 8 is fixed to the pickup chassis 10 by fixing the photodiode board 9 to the pickup chassis 10 with screws 12.

At that time, the spatial position of the photodiode 8 is adjusted so that the spot position of the reflected return light from the recording surface of the CD is at the reference position on the photodiode 8, and then the screw 1 is
We are trying to perform the fixing work according to 2.

[Problems to be Solved by the Invention] However, in the conventional method for attaching the photodiode board to the pickup chassis, the photodiode 8 is fixed with screws as described above. During the screw tightening work, the position of the photodiode 8 may be displaced due to strain caused by screw tightening, and it takes extra time to correct the positional displacement, resulting in a slowdown of the work speed.

In addition, in the conventional method for attaching the photodiode board to the pickup chassis, the photodiode board 9 is fixed to the pickup chassis lO with screws, so when manufacturing the optical pickup, the photodiode 8
Even if the position of the photodiode 8 is properly adjusted, there is a problem in that the position of the photodiode 8 shifts because the screw 12 loosens over time during the use of the optical pickup.

The present invention is intended to solve the above-mentioned problems, and provides a method for attaching a photodiode substrate to a pickup chassis, which prevents the photodiode from shifting its position and improves the work of attaching the photodiode substrate to the pickup chassis. The purpose is to provide an installation method.

[Means for Solving the Problems 1] A method for attaching a photodiode substrate to a pickup chassis according to the present invention includes (a) mounting the lower surface of the photodiode substrate supporting the a+ photodiode on the pickup chassis via an anaerobic adhesive; +b+ a step of adjusting the position of the photodiode by moving the photodiode substrate on the pickup chassis before the anaerobic adhesive solidifies; A step of supplying a curing adhesive between the photodiode substrate and the pickup chassis; (d+ After the steps (b) and (C) above, the ultraviolet curable adhesive of (C) above is irradiated with ultraviolet rays and cured. The method is characterized in that it consists of a step of causing

[Function] According to the above means, the lower surface of the photodiode substrate is placed on the pickup chassis via an anaerobic adhesive, and the photodiode substrate is moved before the anaerobic adhesive solidifies. Adjust spatial position. Also, before and after this, an ultraviolet curing adhesive is applied between the photodiode substrate and the pickup chassis, and after adjusting the position of the photodiode, this anaerobic adhesive is irradiated with ultraviolet rays to cure, and the photodiode substrate is attached to the pickup chassis. Temporarily fix it. Then, over time, the anaerobic adhesive solidifies, and the photodiode substrate becomes firmly fixed to the pickup chassis.

Therefore, the photodiode position does not shift due to strain when tightening the screws, which is the case in the past, so there is no need to correct the positional shift, and the work speed of attaching the photodiode board to the pickup chassis is greatly increased. It will be improved.

In addition, since the photodiode board and pickup chassis are fixed with adhesive instead of screws as in the conventional method, the position of the photodiode gradually shifts during the use stage after manufacturing the optical pickup as in the conventional method. There's nothing left to do.

[Example] The present invention will be described in detail below based on the drawings.

FIG. 1 is a cross-sectional view showing a photodiode substrate and a pickup chassis fixed to each other according to an embodiment of the present invention, and FIG. 2 is a section for explaining the temporarily fixed portion of the photodiode substrate and pickup chassis in FIG. 1. FIG.

In FIG. 1, reference numeral 20 indicates a pickup chassis, and 21 indicates an aluminum photodiode substrate. Leads 8 a of the photodiode 8 are fixed to the photodiode substrate 21 with solder 11 . The lower surface of the photodiode substrate 21 is fixed to the pickup chassis 20 with an anaerobic adhesive 22. The pickup chassis 20 also includes side portions 2 of the photodiode board 21, (
A recess 20a is formed at a position facing a, and the photodiode substrate 21 and the pickup chassis 20 are also fixed by the ultraviolet curable adhesive 23 filled in the recess 2Oa. In particular, as shown in FIG. 2, a protrusion 20b is formed in the recess 20a of the pickup chassis 20, which improves the adhesive strength particularly in the direction of the arrow α in FIG. .

Next, a method of attaching and fixing the photodiode substrate 21 shown in FIG. 1 to the pickup chassis 20 will be explained.

In this embodiment, first, the photodiode 8 is attached with an adhesive (for example, adhesive TB-3062 manufactured by ThreeBond).
The photodiode substrate 21 is bonded to the photodiode substrate 21. Then, an anaerobic adhesive 22 (
For example, an adhesive LX-0383 manufactured by Loctite Corporation is applied, and the lower surface of the photodiode substrate 21 is placed on a predetermined location of the pickup chassis 20. Thereafter, the spatial position of the photodiode 8 is adjusted so that the spot of the reflected return light from the recording surface of the CD is at the reference position of the photodiode 8. An anaerobic adhesive 22 is interposed between the pickup chassis and the anaerobic adhesive 22, but since it takes a considerable amount of time for the anaerobic adhesive 22 to solidify, the photodiode substrate 21 can be moved freely within that time. The position of the photodiode 8 can be adjusted by shifting the position. In particular, the adhesive LX for surface attachment
-0383 is viscous and does not have a rough feel and is easy to adjust.

When the position adjustment of the photodiode 8 is completed, the recess 20a of the pickup chassis 20 is filled with an ultraviolet curable adhesive 23, and then the ultraviolet curable adhesive 23 is irradiated with ultraviolet rays to harden it, and the both sides of the photodiode substrate 21 are sealed. 2. Temporarily fix (a) and the pickup chassis 20. Then, after a predetermined period of time has elapsed in this state, the anaerobic adhesive 22 solidifies, and the photodiode substrate 21 and the pickup chassis 20 are firmly fixed. Note that the ultraviolet curable adhesive 23 may be applied in advance before position adjustment.

As described above, according to the present embodiment, the positional deviation of the photodiode 8 due to the strain during screw tightening as in the conventional case does not occur, so there is no need to correct the positional deviation, etc. The installation speed of the pickup chassis 20 can be greatly improved.

In addition, the photodiode board 21 and the pickup chassis 20 are not fixed with screws as in the conventional case, but with an anaerobic adhesive 22.
Since the photodiode 8 is fixed with the ultraviolet curing adhesive 23, it is possible to avoid problems such as the position of the photodiode 8 gradually shifting during the 7th stage of use after manufacturing the optical pickup as in the past. Become.

[Effects] As described above, according to the present invention, the photodiode substrate is fixed to the pickup chassis with an adhesive instead of screw tightening, so there is no possibility of the photodiode position shifting due to strain caused by screw tightening as in the conventional method. This eliminates the need for correction of the photodiode substrate and its positional deviation, and the work speed for attaching the photodiode board to the pickup chassis can be greatly improved.

In addition, since the photodiode board and pickup chassis are fixed with adhesive instead of screws as in the conventional method, the position of the photodiode gradually shifts during the use stage after manufacturing the optical pickup, unlike in the conventional method. You will be able to avoid inconveniences such as

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a photodiode substrate and a pickup chassis fixed to each other according to an embodiment of the present invention, and FIG. 2 is a section for explaining the temporarily fixed portion of the photodiode substrate and pickup chassis in FIG. 1. FIG. 3 is a perspective view showing an optical pickup used in a CD player, and FIG. 4 shows a fixing structure between a photodiode board and a pickup chassis using a conventional method for attaching a photodiode board to a pickup chassis. FIG.

Claims (1)

[Claims] 1. (a) a step of placing the lower surface of a photodiode substrate supporting the photodiode on a pickup chassis via an anaerobic adhesive; (b) solidifying the anaerobic adhesive; (c) Before and after the step (b) above, applying an ultraviolet curable adhesive to the photodiode substrate and the pickup chassis. and (d) after the steps (b) and (c) above, the step of curing the ultraviolet curable adhesive of (c) by irradiating it with ultraviolet rays. How to attach the board to the pickup chassis