JPH01159851A - Photodetector for light pick-up - Google Patents

Abstract

PURPOSE:To improve the efficiencies of sticking and aligning detecting pieces by, for four photodetectors chamfering each one point of corners in one and the same position relation to the polarization directions, combining them, adhering them to each other on a transparent substrate, and unifying them. CONSTITUTION:Each one point of the corners in one and the same positions to the polarization directions of four rectangular photodetectors 1 are chamfered, further, before they are joined to a sensor 3, the pieces are stuck on a transparent substrate 2 without a polarization character, and the four photodetectors are unified beforehand. As a result, respective proper polarization directions at the time of combining the four photodetectors 1 can be easily identified, and since the cross of the center of the four photodetectors 1 is combined beforehand, the alignment of a central position relation with the quadrisected sensor 3 can be carried out easy. Thus, the adhering and alignment of the photodetectors can be made efficient.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a differential detection type optical pick-up device used in a magneto-optical disk drive.

[Summary of the invention]

In the present invention, in a combined four-part analyzer (polarizing plate) that is closely connected to the sensor of a differential detection type optical pickup used in a magneto-optical disk drive, a four-part analyzer (polarizing plate) is
By chamfering one corner that is in the same positional relationship with respect to the polarization direction of each analyzer, the alignment of each polarization direction in the assembly of four analyzers can be easily identified, Furthermore, by bonding the four analyzers closely together on a non-polarizing transparent substrate before directly bonding them onto the sensor, the efficiency of assembling the analyzers onto the sensor can be increased. This makes it possible to improve the accuracy of the pickup.

[Conventional technology]

In a differential detection type optical pickup used in a magneto-optical disk drive, an analyzer must be closely bonded to each of the four-split sensors with the polarization direction aligned.

Until now, we have used a commercially available polarizing plate (NH-22 manufactured by Polaroid).
etc.) are cut into rectangles according to the size of the sensor and pasted directly onto each of the four-part sensor using UV adhesive, etc. At that time, the polarization direction of the analyzer is
It was necessary to check each individually cut polarizing plate (analyzer) through the polarizing plate.

Furthermore, in order to attach it directly to the sensor, it was necessary to precisely align the four-part sensor with the four analyzers.

[Problem that the invention seeks to solve]

However, with the above-mentioned conventional technology, when attaching a cut rectangular analyzer to a 4-split sensor, the direction of attachment must be determined while checking the polarization direction of the analyzer individually by sandwiching it between polarizing plates. It was very complicated.

In addition, in the method of directly setting and pasting onto the sensor,
It is difficult to accurately align the four analyzers and the four-part sensor, which greatly reduces assembly efficiency.

Therefore, in order to solve these conventional problems, the present invention
When cutting the analyzer to the size of the sensor, a mark is attached to identify the polarization direction, making it easier to confirm the position of the analyzer, and pasting the four analyzers on the 4-split sensor. This is intended to improve the efficiency of alignment.

[Means for solving problems]

In order to solve the above problem, the analyzer for an optical pickup of the present invention has a four-part analyzer that is assembled in close proximity to the sensor of a differential detection type optical pickup.
After chamfering one of the corners that have the same positional relationship with respect to the polarization direction of the two light beams, they are combined.

Furthermore, the present invention is characterized in that the four analyzers are closely bonded and integrated on a transparent substrate before being directly and closely bonded onto the sensor.

[For production]

According to the present invention, by chamfering one corner located at the same position with respect to the polarization direction of a rectangular analyzer, it is possible to easily trace each polarization direction when four analyzers are combined. Identification has become easier and alignment has become easier.

Furthermore, by bonding the four analyzers together on a non-polarizing transparent substrate before bonding them to the sensor, it is easier to handle when setting them on the sensor, and the four analyzers are integrated. Since the crosses at the center of the photon are already combined, it is easy to align the center position with the 4-split sensor, and the efficiency of assembling the analyzer and pasting it to the sensor can be greatly improved. At the same time, it has become possible to obtain stable accuracy.

〔Example〕

FIGS. 1A to 1D are process diagrams for explaining the assembly procedure of the optical pick analyzer of the present invention.

In FIG. 1(A), 1 is an analyzer according to the present invention, and four rectangular analyzers (a), (b), (c), and (d) are each cut to match the size of the sensor. for,
1 of the angles that have the same positional relationship with respect to the polarization direction (→ mark)
Some places are chamfered.

These four analyzers (a), (b), (C), (d) are
If they are assembled on the transparent substrate 2 with the chamfered part facing outward, the result will be as shown in Figure 1 (B), and each analyzer will automatically be placed on the 4-split sensor to determine the required polarization direction. It can be set to .

This consists of four analyzers (a), (b), (C), (d)
It can be seen that no matter how you combine them, the result will be the same. This 4
When combining two analyzers, they are combined on a transparent acrylic substrate and bonded together using UV adhesive.

Align this integrated analyzer with the center cross of the four-part sensor 3 shielded by the glass shield 4 (see Figure 1).
C) Figure 11 (
The finished product will look like D).

(Figure 1 (D> is a cross-sectional view.) By doing this, it is easy to identify the analyzers when they are combined, and by assembling and integrating them on a transparent substrate in advance, Alignment with the 4-split sensor takes only a short time.
It has become possible to significantly improve productivity and stabilize characteristics.

〔Effect of the invention〕

As explained above, the present invention provides a combined four-part analyzer for use in a differential detection type optical pickup.
An angle at the same position with respect to the polarization direction of the analyzers, 1
By chamfering several parts, the positional relationship when the four analyzers are combined can be easily identified.

Furthermore, when bonding to the sensor, by combining and gluing the four analyzers onto the transparent substrate in advance and integrating them, we aim to improve the efficiency of aligning the four-split sensor with the center cross. It is something.

In addition, in the examples, chamfering in which the corners are cut straight is described, but other types of cuts such as R-shaped cuts as shown in Fig. 2, Fig. 2 (a), notches Fig. 2 (b), etc. As long as it can be identified from either side of the photon, the present invention can be easily analogized and is included in the present invention.

[Brief explanation of the drawing]

FIGS. 1A to 1D are process diagrams showing the procedure for assembling an analyzer for an optical pickup according to the present invention. FIG. 2(A) is a diagram showing an embodiment in which the chamfered shape of the present invention is an R-shape, and FIG. 2(B) is a diagram showing an embodiment in which the chamfered shape of the present invention is made into a notch shape. 1...Analyzer (polarizing plate) 2...Transparent substrate 3...4-split sensor 4...Glass shield or above Applicant: Seiko Epson Co., Ltd. Agent Patent attorney Tsutomu Mogami (1 other person) 1st Figure 2

Claims (2)

[Claims] (1) After chamfering one of the corners of the four analyzers that are combined in close proximity to the sensor of the differential detection optical pickup that are in the same position relative to the polarization direction of the four analyzers, An analyzer for optical pickup, which is characterized by: (2) The optical pickup according to claim 1, characterized in that the four analyzers are closely bonded and integrated on a transparent substrate before being directly bonded to the sensor. Analyzer.