JP2637620B2 - Method for manufacturing optical unit in optical information recording / reproducing apparatus - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing an optical unit in an optical information recording / reproducing apparatus.

[Prior Art] FIGS. 4 to 9 show a conventional optical information recording / reproducing apparatus.

First, the overall schematic configuration of the optical information recording / reproducing apparatus will be described with reference to FIG.

The optical information recording / reproducing apparatus has a motor (8) for rotating a disk (7) as an information recording carrier, and information pits (9) on the disk (7) are provided near the motor (8).
An optical unit that reproduces information by irradiating a light beam to the optical disc is disposed.

The information content of the information pit (9) of the disc (7) is stored depending on the presence or absence of a depression or the length. The optical unit has an optical system main body (15) as a mounting base for each optical component, and a light source (1) for emitting a light beam (5) is arranged on a side surface of the optical system main body (15). A diffraction grating (2) that faces the light source (1) and is arranged on the optical path of the light beam (5) to convert the light beam (5) into a parallel light beam.

Further, a half mirror (3) is disposed on the optical path of the light beam (5) at a predetermined angle (45 °) with respect to the optical path, and on the optical path polarized by the half mirror (3). A collimating lens (4) is arranged.

An actuator section barrel (14) is provided above the optical system body (15), and an objective lens (6) is provided above the actuator section barrel (14). Then, the objective lens (6) is moved in the vertical direction (arrows A and A 'directions) in the actuator barrel (14) to focus the objective lens (6) on the information pit (9) on the disk (7). And a track drive (6a) for moving the objective lens (6) in the radial direction (arrows B and B ') of the disc (7). .

A sensor lens (11) for enlarging the reflected light (13) transmitted through the half mirror (3) is disposed below the half mirror (3), and a sensor lens is disposed below the sensor lens (11). A photodetector (12) that receives the reflected light enlarged by (11) is arranged.

FIG. 6 is a perspective view of the optical unit, showing a light source (1).
Is held by the holder (16), and the holder (1
6) is screwed to the optical system body (15), and both sides are fixed with adhesives (31a) and (31b). As shown in FIG. 8, the diffraction grating (2) is held by a holder (17), and is held by the optical system main body (15) so as to be rotatable around the light beam (5). An elastic machine (18) is interposed between the holder (16) and the holder (17).

Further, the sensor lens (11) is held by a holder (19), and is parallel to the reflected light (13) (arrows F,
F 'direction) is slidably held in the optical system body (15),
After the position is adjusted by sliding, the holder (19) and the optical system main body (15) are fixed by the adhesive (32).

The half mirror (3) is pressed and held by a leaf spring (21) on a 45 ° surface (20a) (20b) provided on the optical system main body (15) and is fixed by an adhesive (30). .
(L) is the thickness of the half mirror (3).

FIGS. 6, 7, and 9 are views for explaining the mounting structure of the light source (1) and the half mirror (3). As shown in the drawings, a U-shaped bent portion (22a) and an L-shaped bent portion are shown. (22b) and (22c), and the leaf spring (21) has holes (23a) for positioning,
(23b) is protruding.

Further, the leaf spring (21) is provided with positioning holes (23a), (23
b) The boss (24) projecting from the optical system body (15)
a) and (24b) are positioned and held by fitting.

The optical detector (12) is held by a plate (25), and is slidably held on a plane (26) of the optical system main body (15) in the directions of arrows G and G '.

 Next, the operation will be described.

The light beam (5) emitted from the light source (1) is a diffraction grating (2), a half mirror (3), a collimating lens (4).
Then, the light is irradiated onto the disk (7) through the objective lens (6) to form light spots (10a), (10b) and (10c) on the disk (7) as shown in FIG.

On the other hand, on the disk (7), information pits (9) representing the content of information communication by, for example, length are sequentially arranged concentrically or spirally to form an information track.

Then, the reflected light (13) from above the disk (7) rotated by the motor (8) travels in the reverse direction of the incident optical path, passes through the half mirror (3), passes through the sensor lens (11), and passes through the photodetector (12). ) And is converted into an electric signal by the photodetector (12).

Then, the information recorded on the disc (7) is reproduced by processing the output signal of the photodetector (12).

On the other hand, based on the output signal of the photodetector (12), the focus directions (arrows A and A ') and the track directions (arrows B) of the light spots (10a), (10b), and (10c) on the disk (7). , B ′ direction) can be extracted.

When the disk (7) rotates, vertical vibration in the directions of arrows A and A 'and eccentric operation in the directions of arrows B and B' occur. Therefore, the objective lens (6) is moved in the directions of the arrows A and A 'by the focus driving device (6b) to focus on the vertical vibration by the defocus signal obtained from the output signal of the photodetector (12). In addition, for the eccentric operation, the track driving device (6a) moves the objective lens (6) in the directions of arrows B and B 'according to the track shift signal to correct the deviation from the track position.

By the way, the ambient temperature at which the optical information recording / reproducing apparatus operates is usually about + 5 ° C. to + 50 ° C., and it is necessary to guarantee stable operation performance at this temperature. Generally, when the optical system main body (15) is formed of an inexpensive material, for example, zinc die-cast, the linear expansion coefficient of the material tends to be large, and each optical component can be accurately formed at room temperature by using the optical system main body (15). Even when the optical system is assembled, thermal deformation of the optical system body (15) at high and low temperatures causes an error in the accuracy of placement of each optical component. In addition, if the bonding strength between the optical system body (15) and each optical component is weak, or there is residual stress during assembly, etc., when the temperature is returned to room temperature, the accuracy of positioning of each optical component will deviate from the initial position, resulting in light There is a possibility that the photoelectric conversion characteristics of the detector (12) may deteriorate. Therefore, as described above, the adhesive (30),
(31a), (31b), and (32) are used to secure the reliability performance by strengthening the adhesion between the optical system body (15) and the half mirror (3), the holders (16), and (19). I have.

[Problems to be Solved by the Invention] Since the optical unit of the conventional optical information recording / reproducing apparatus is configured as described above, residual stress and the like at the time of assembling and bonding each optical component to the optical system body are reduced. If there,
In the initial temperature state (before the temperature test), the arrangement of each optical component may be shifted due to the normal temperature return state after the environmental temperature change (high / low). As a result, the photo-electric conversion characteristics of the photodetector may deteriorate. There was a problem that would.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has been made in an optical system in which the photo-electric conversion characteristics of a photodetector do not deteriorate in a normal temperature return state after an environmental temperature change (high / low temperature). An object of the present invention is to provide a method for manufacturing an optical unit of a type information recording / reproducing apparatus.

[Means for Solving the Problems] A method of manufacturing an optical unit in an optical information recording / reproducing apparatus according to the present invention comprises assembling an optical system main body and an optical system component which is not adjusted after assembling and bonding. The optical system body is heat-treated (annealed) at a temperature higher than the environmental guarantee temperature and lower than the glass transition temperature of the adhesive, and then assembled to the final state.

[Operation] The method of manufacturing an optical unit according to the present invention involves assembling an optical system main body and an optical component that is not adjusted after assembly, and then performing heat treatment at a predetermined temperature after bonding, so that residual stress during assembly and bonding is removed. If the optical information recording / reproducing apparatus is used in the environment, the optical components set at the time of manufacture do not shift.

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

Since the configurations of the optical information recording / reproducing device and the optical unit are the same as those of the conventional example, only the assembly process of the optical components will be described below.

FIG. 1 is a block diagram in which the assembling process of the optical component in the present embodiment is compared with the conventional assembling process. The half mirror (3) and the holder (16) are attached to the optical system main body (15), and the adhesive (30) is used. ), (31a) and (31b) after application and curing,
Heat treatment (annealing) at a temperature higher than the environmental guarantee temperature (high temperature) 50 ° C. and lower than the glass transition temperature of the adhesive, and then assembling and adjusting the rest. Due to the heat treatment of the optical unit in the intermediate step as described above, the residual distortion at the time of assembling and bonding the half mirror (3) and the holder (16) is released,
In the use environment, the photo-electric conversion characteristics of the photo detector (12) do not deteriorate.

FIGS. 2 and 3 show data showing the effect of this embodiment. Fig. 2 shows the deviation data from the initial position (before the test) of the reflected light (13) incident on the photodetector (12) after the heat treatment temperature of 80 ° C and after the 70 ° C environmental test, and Fig. 3 shows the heat treatment temperature. Ten
The data of the amount of deviation from the initial position (before the test) of the reflected light (13) incident on the photodetector (12) after the environmental test at 0 ° C and 70 ° C is shown. Incidentally, the glass transition temperature of the adhesive used is 85 ° C.

From FIGS. 2 and 3, it can be seen that the optical unit heat-treated at a temperature higher than the predetermined environmental temperature 70 ° C. and lower than the glass transition temperature 85 ° C. of the adhesive has a higher setting than the optical unit heat-treated at a temperature higher than the glass transition temperature. It can be understood that the deviation from the set position is limited within a predetermined range, and good photo-electric conversion characteristics of the photodetector are expected.

[Effects of the Invention] As described above, according to the present invention, the heat treatment (annealing) is performed during the assembly of the optical unit in order to remove the residual stress due to the assembly and bonding. In other words, if the environment is in a normal use range, it is possible to obtain a photodetector whose photo-electric conversion characteristics do not deteriorate.

[Brief description of the drawings]

FIG. 1 is a block diagram of an assembling process and a conventional assembling process block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing experimental data for explaining the effects of the embodiment of the present invention, and FIG. FIG. 4 is a view showing experimental data for explaining the effect of a comparative example with the present invention, FIG. 4 is an overall schematic configuration diagram of an optical information recording / reproducing apparatus, FIG.
FIG. 7 is a perspective view showing the optical unit, FIG. 7 is a side view of the optical unit of FIG. 6 viewed from the direction of arrow G, FIG. 8 is a central side view of the optical unit of FIG. 6, and FIG. It is an exploded perspective view of a holding part. In the figure, (3) is a half mirror, (5) is a light beam,
(7) is a disk, (15) is an optical system main body, (16) is a holder, and (30), (31a) and (31b) are adhesives. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

(57) [Claims] 1. A method of manufacturing an optical unit in an optical information recording / reproducing apparatus for recording or reproducing information by irradiating an information recording carrier with a light beam, comprising: A first step of forming an optical unit by adhering and fixing the optical unit at a temperature higher than the environmental guarantee temperature of the optical information recording / reproducing apparatus and lower than the glass transition temperature of the adhesive after the first step. And a second step of performing a heat treatment on the optical information recording / reproducing apparatus.