JPH03130941A - Optical pickup device - Google Patents

Abstract

PURPOSE:To reduce the reduction of adjusting accuracy when a photodetector is fixed and to reduce the dispersion of initial performance as well by fixing the photodetector at a prescribed position in the recessed part of an optical unit by using an adhesive when the photodetector is fixed to the optical unit. CONSTITUTION:A photodetector 7 is housed in a recessed part 20, which is formed in an optical unit 1, and adjusted so as to be set at a focal position by using a normal adjusting device. After the adjustment, the photodetector is fixed by pouring an adhesive agent 24 from the opening end of the recessed part 20 to the side surface of the photodetector 7 while maintaining this state. After the photodetector is fixed, a lead terminal 7a of the photodetector 7 and a lead wire 22 are electrically coupled by using soldering. Thus, since the photodetector 7 is directly fixed to the optical unit 1 by the adhesive agent 24, the position of the photodetector 7 can be prevented from being deviated when the photodetector is fixed. Further, the photodetector can be fixed extremely speedily and exactly and fixed at the optimum position.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical pickup device, and particularly to a fixing structure for fixing a photodetector to an optical unit.

[Prior Art] An example of the prior art will be explained based on FIGS. 4 to 6.

FIG. 4 is a side view showing an optical unit of a conventional optical pickup device, and in the figure, (1) indicates an optical unit;
(2) is a semiconductor laser diode that is press-fitted into the optical unit (1), and (3) is a semiconductor laser diode that is press-fitted into the optical unit (1).
A half mirror (4) is glued and fixed to the diffraction grating holder (5) to which a diffraction grating (13), which will be described later, is glued and fixed for dividing the laser light from the semiconductor laser diode (2) into a plurality of beams. (4) is a spring that presses and fixes the photodetector (7), and (6) is a first adjustment plate made of, for example, beryllium or copper that fixes the photodetector (7), and is elastically deformed by tightening the adjustment screw (8). It has a groove (9). (10) is a second adjustment plate that fixes the first adjustment plate (6) with a screw (11), (12) is a screw that fixes the second adjustment plate (10), and (14) is a flexible plate. Board (FPC), arrow Z is the first adjustment plate (6)
Indicates the adjustment direction of the optical axis direction.

FIG. 5 is a bottom view of the same, and in the figure, symbols (1),
(6) to (14) have the same configuration as in Fig. 3, and the arrow
1Y indicates the adjustment direction in a plane perpendicular to the optical axis of the second adjustment plate (1o).

FIG. 6 is a side sectional view showing the optical path of laser light emitted from the semiconductor laser diode (2), and in the figure, symbols (1) to (7), (9) to (11), (13),
(14) has the same configuration as that in FIG. 4, and (15) uses arrows by known servo means (not shown) to always focus the light on the signal surface of the disk (16) on which music information etc. are recorded. This is an objective lens that moves in the W direction. In addition, in the figure, the laser beam from the semiconductor laser diode (2) is indicated by an optical path T.

Next, the fixing operation of the photodetector will be explained.

The spot shape on the four-divided photodetector (7) becomes circular at the focused position. Using this property, the photodetector (7) is moved by arrows x and y so that the light output on each divided pattern is equal.

It is moved in two directions using a known adjustment device and adjusted on the order of 1 micron.

That is, when the spot shape on the photodetector (7) is elliptical, the photodetector (7) is located at a position shifted from the focal point. To adjust this, rotate the adjustment screw (8) to move the photodetector (7) in the direction of arrow Z and make the adjustment.

Furthermore, if the spot shape on the photodetector (7) is circular, there is no need to perform adjustment in the arrow Z direction.
Adjust the adjustment plate (10) by moving it in the direction of the arrow XSY so that the light output of each pattern is equal, and then tighten the screw (10).
Fix with 2).

[Problems to be Solved by the Invention] Conventional Problems As described above, in the conventional configuration, after the adjustment in the arrow XSY direction is completed, the screw (12) is tightened and the second adjustment plate (
10) to the optical unit (1), but with the screw (12)
) The second adjustment plate (10) moved during tightening, and it was therefore necessary to repeatedly adjust and fix it to the optimum position.

Moreover, this required a long time for adjustment.

Furthermore, since the position cannot be determined accurately without re-adjustment, there is a problem that the initial performance varies widely.

Further, the adjustment in the two directions of the arrows is also fixed at the position S by turning the screw (8), but the mechanism is complicated and the parts are expensive.

In addition, since the adjustment plates (6) and (10) are used, there is a drawback that the optical pickup device becomes expensive.

Purpose of the Invention The present invention has been made to solve the above problems, and provides an optical pickup device that has a simple configuration and is inexpensive, and furthermore, does not cause displacement of the photodetector when the photodetector is fixed. The purpose is to provide the following.

[Means for Solving the Problems] An optical pickup device according to the present invention includes an optical unit including an optical component and a communication hole through which reflected light from a disk on which a signal is formed passes, and the optical unit. a photodetector that receives reflected light from the disk on which a signal is formed and outputs an electrical signal in accordance with the signal; a recessed portion having a space for movably accommodating reflected light at least in a plane perpendicular to the optical axis direction;
and an adhesive portion for fixing the photodetector at a predetermined position in the recess.

[Function] The photodetector fixing structure of the optical pickup device according to the present invention is such that the photodetector is directly fixed at a predetermined position in a recess formed in the optical unit with an adhesive.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a side view showing an optical unit according to an embodiment of the present invention, FIG. 2 is a schematic sectional view of the main part of FIG. 1, and FIG. 3 is a perspective view showing the fixing operation.

In the figure, symbols (2) to (5), (7), and (13) are the same configurations as those shown in the conventional example described above.

In the figure, (20) is a recess formed in the optical unit (1), and the recess (20) is a recess formed in the optical unit (1).
A communication hole (21) formed on the bottom surface and allowing reflected light to pass through.
It is inserted.

Further, the recess (20) can accommodate the photodetector (7), and in the accommodated state, the photodetector (7) is placed in the fourth and fifth positions.
It has a space in which it can move in the X1YSZ directions shown in the figure.

The lead terminal (7a) of the optical detector (7) that is housed and fixed in the recess (20) is bent toward the lower surface and is inserted into the recess (20).
20), the tip of the lead terminal (7a) is formed so as to protrude from the lower surface of the optical unit (1).

Next, the fixing operation of the photodetector according to one embodiment will be explained.

First, as shown in FIG. 3, a photodetector (7) is housed in a recess (20) formed in the optical unit (1).

Next, using a known adjustment device, the photodetector (7) is adjusted so as to be placed at the focal point, as in the conventional case.

After the adjustment, the adhesive (24) is flowed into the side surface of the photodetector (7) from the open end of the recess (20) and fixed while maintaining that state.

After fixing, the lead terminal (7a) of the photodetector (7) and the lead wire (22) are electrically coupled by solder (23).

As mentioned above, the photodetector (7) is directly connected to the optical unit (1).
), since it is fixed with adhesive (24), it is possible to prevent the photodetector (7) from shifting when it is fixed, and moreover, it can be fixed very quickly and accurately at the optimum position.

In addition, in the case of a pickup device having a configuration in which a focusing point adjusting means is installed, the adjustment is performed in the arrow XSY direction, and the optical detector (7) is adjusted by the built-in focusing point adjusting means.
) After adjusting the beam spot to the optimum position on the four-division element, the photodetector (7) is fixed to the optical unit (1) with adhesive (24) in the same way as in the above case.

Further, in one embodiment, electrical connections were made using lead wires, but it goes without saying that a flexible substrate may also be used.

Further, the adhesive is not particularly limited, but an ultraviolet curing adhesive is suitable for use.

[Effects of the Invention] As explained above, according to the present invention, the photodetector is fixed at a predetermined position in the recess of the optical unit with adhesive, which reduces the decrease in adjustment accuracy during fixation. , it is possible to reduce variations in initial performance, thereby greatly improving reliability.

Further, since an adjustment plate and the like can be omitted, the structure is simple and inexpensive.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an optical unit of an optical pickup device according to an embodiment of the present invention, FIG. 2 is a schematic sectional view of the main part of the optical unit shown in FIG. 1, and FIG. FIG. 4 is a side view showing an optical unit of a conventional optical pickup device, FIG. 5 is a bottom view of the optical unit shown in FIG. 4, and FIG. 6 is a semiconductor laser diode. FIG. In the figure, (2) is a semiconductor laser diode, (3)
is a half mirror (7) is a photodetector, (20) is a recess, (
21) is a communicating hole, and (24) is an adhesive portion. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] An optical unit including an optical component and having a communicating hole through which reflected light from a disk on which a signal is formed passes, and a light reflected from the disk on which a signal is formed through the optical unit. a photodetector that receives light and outputs an electrical signal according to the signal; and a surface formed at the end of the communication hole and perpendicular to at least the optical axis direction of the reflected light that enters the photodetector. What is claimed is: 1. An optical pickup device comprising: a recess having a movable space therein; and an adhesive portion for fixing the photodetector at a predetermined position in the recess.