JPH0452822Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

This invention relates to a photodetector support mechanism that supports a photodetector for focus adjustment in an optical pickup used in a compact disc player, a video display player, etc. in a position adjustable manner.

[Conventional overview]

A support member comprising a box-shaped frame for supporting the photodetector and at least two bent arms connected to the box-shaped frame, the supporting member being supported by the substrate at the tips of the bent arms, and the support member being rotatably supported by the substrate. It consists of at least two eccentric cams whose cam surfaces are in contact with the box-shaped frame of the support member, and by rotating the eccentric cams, the box-shaped frame is moved in a plane parallel to the photodetector, and the position of the photodetector is finely adjusted. This is an adjustable photodetector support mechanism.

[Conventional technology]

Figure 3 shows the optical path of a conventionally known optical pickup, in which the light emitted from the laser diode 5 is irradiated onto the signal recording surface 6 of the disk via the optical system, and the reflected light is A portion of the light is reflected in the right angle direction by a prism and guided to a photodetector 4 for focus adjustment.
The focus is adjusted so that the spot in the image is minimized. If the position of the photodetector 4 shifts, crosstalk between the focus direction and the tracking direction will occur in the pick-up output, causing oscillation, etc.
It is necessary to install the photodetector 4 so that its best point exactly matches the optical axis (with an error of 2 to 3 μm or less).
As shown in the figure, when attaching the photodetector unit 8 to the body of the optical pickup, the photodetector unit 8 is held by a jig 9, and the position of the jig 9 is determined while observing the output of the photodetector 4 with an oscilloscope. After moving it and determining the optimal mounting position, the photodetector unit 8 was screwed to the body. However, this method requires the use of the jig 9 during assembly, which is time-consuming, and the mounting position may shift slightly due to the tightening torque when screwing, making it difficult to assemble and adjust. The drawbacks were that it required skill, was difficult to mass produce, and was difficult to fine-tune after assembly.

[Problem that the invention attempts to solve]

The purpose of this invention is to improve the drawbacks of the conventional device described above, and to provide a support mechanism that does not require the use of jigs or the like during assembly and is easy to assemble and finely adjust thereafter.

[Means to solve the problem]

In order to achieve the above object, the photodetector support mechanism of this invention includes a box-shaped frame for supporting the photodetector, and at least two bent arms connected to the box-shaped frame. and at least two eccentric cams that are rotatably supported by a base plate and have their cam surfaces abutted against the box-shaped frame of the support member.

[Effect]

By doing this, the box-shaped frame can be moved in a plane parallel to the photodetector by rotating the eccentric cam, so that the position of the photodetector can be easily finely adjusted after assembly.

【Example】

An embodiment of this invention will be described with reference to the drawings. FIG. 1A is a front view thereof, FIG. A supporting member 2 made of slightly elastic plastic is integrally formed with a substrate 1 to be fixed to an optical pickup by so-called outsert molding. The support member 2 has a box-shaped frame 2a in the center that fits and supports the photodetector 3, and has two arms 2b extending bent from both sides, and bosses 2c protruding from the rear surface of the tips of the two arms 2b extend into the through-holes of the substrate 1. Fixed. Eccentric cams 4 made of plastic are provided on the right side and lower side (in the same figure) of the box-shaped frame 2a (formed by outsert molding at the same time as the support member 2), and their cam surfaces are attached to the box-shaped frame 2a. abutting,
By rotating the two eccentric cams 4, the position of the box-shaped frame 2a can be moved laterally and vertically, respectively. When assembling, as shown in FIG.
Fit the photodetector 3 (glue if necessary) and attach the front of the photodetector 3 to the window 1 of the substrate 1.
It is sufficient to simply attach the substrate 1 to the optical pickup 4 while facing the optical pickup 4. Further, to finely adjust the position of the photodetector 1, the optimum position can be determined by rotating and adjusting the two eccentric cams 4 while viewing the output of the photodetector with an oscilloscope.

[Effect of the idea]

As explained above, the photodetector support mechanism of this invention includes a box-shaped frame for supporting the photodetector and at least two bent arms connected to the box-shaped frame, and is supported on the substrate at the tip of the bent arms. the support member, and at least two eccentric cams that are rotatably supported by the base plate and have their cam surfaces abutted against the box-shaped frame of the support member.By rotating the eccentric cams, the box-shaped frame is By moving in a plane parallel to the photodetector, the number of parts is small, no jigs are required, and assembly is easy. Fine adjustments can be made at any time after assembly, and the method is extremely simple. It has a unique function and effect.

[Brief explanation of the drawing]

Fig. 1...Front view and sectional view of an embodiment of this invention, Fig. 2...A perspective view showing its assembly, Fig. 3...An explanatory diagram showing the optical path of the optical pickup, Fig. 4...
FIG. 2 is a perspective view showing the assembly of a conventional device. DESCRIPTION OF SYMBOLS 1...Substrate, 1a...Window, 2...Supporting member, 2
a...Box-shaped frame, 2b...Arm, 2c...Boss, 3...
... Photodetector, 4 ... Eccentric cam, 5 ... Laser diode, 6 ... Signal recording surface, 7 ... Prism, 8 ... Photodetector unit, 9 ...
…jig.

Claims (1)

[Claims for Utility Model Registration] (a) A support comprising a box-shaped frame for supporting a photodetector and at least two bent arms connected to the box-shaped frame, the support being supported by a substrate at the tips of the bent arms. (b) at least two eccentric cams that are rotatably supported by the base plate and have their cam surfaces abutted against the box-shaped frame of the support member; and (c) the box is rotated by rotating the eccentric cams. A photodetector support mechanism characterized by moving a frame in a plane parallel to the photodetector.