JPH05128562A - Optical axis aligning mechanism of optical pickup - Google Patents

Abstract

PURPOSE:To correct the error of the mounting accuracy of a mirror in the middle of an optical path, to improve the yield and to reduce the manufacturing cost by making changeable the position of a condenser lens provided at one end of an arm of a sliding/turning member, thereby to adjust an optical axis. CONSTITUTION:A mirror 4 is bonded and fixed to one end of an arm 22 of a sliding/turning member 2 while being kept parallel to a mirror 3. A lens holder 21 is arranged to be agreed with the smooth surface at one end of the arm 22 of the sliding/turning member 2, and securely connected after it is adjusted to a position shifted by the amount DELTAx.DELTAy of eccentricity of an optical axis due to the error DELTAr.DELTAtheta of the mounting angle of the mirrors 3, 4. Accordingly, even when the eccentricity DELTAr.DELTAtheta is generated, it is possible to suppress the eccentricity of the optical axis on a position detecting sensor 9, namely, the positional shift of spot lights 18, 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical axis alignment mechanism for a shaft sliding type optical pickup in an optical disk device used for an external storage device such as a computer.

[0002]

2. Description of the Related Art A conventional shaft sliding type optical pickup will be described below.

FIG. 5 is an exploded perspective view of a main part of a conventional shaft-sliding optical pickup, and FIG. 6 is a view showing the optical system of FIG. 5 and 6, 1 is a base member, 2 is a sliding and rotating member, 22 is its arm, 3 and 4 are mirrors, 5 is a condenser lens, 6 is a prism mirror, 7 is a laser oscillator,
Reference numeral 8 is a half mirror, 9 is a position detection sensor, 10 is a signal reading sensor, 11 is a rotation center shaft for supporting the sliding rotation member 2, and 12 is an optical disk.

In the above-mentioned structure, the laser beam emitted from the laser oscillator 7 serves as a rotation center shaft for supporting the sliding rotation member 2 fixed to the base member 1 of the optical pickup.
The light is focused on the recording surface 13 of the optical disk 12 via the through holes 11 and the mirrors 3 and 4 arranged on the arm 22 of the sliding / rotating member 2 and the condenser lens 5.

The laser light reflected from the recording surface 13 returns to the above-mentioned optical path and is guided to the position detecting sensor 9 and the signal reading sensor 10 by the prism mirror 6 and the half mirror 8.

FIG. 7 is a schematic diagram of the optical system of the shaft sliding type optical pickup shown in FIG. 6, and FIG. 8 is a schematic diagram of the optical system when rotating in FIG.

First, as shown in FIG. 7, when the mounting angles deviate to the left and right with the mirrors 3 and 4 kept parallel, the optical axis 14 of the laser beam from the mirror 4 to the condenser lens 5 is changed. Eccentricity Δx as shown by the broken line. The return light also reaches the position detection sensor 9 while being decentered by ΔX.

Further, as shown in FIG. 8, when the mirror 3 and the mirror 4 are kept parallel to each other and the mounting angle is shifted up and down by Δθ, the optical axis 14 of the laser beam from the mirror 4 to the condenser lens 5 is changed. It is eccentric by ΔY as shown by the broken line. The return light also reaches the position detection sensor 9 while being decentered by ΔY.

Even if the mounting angles of the mirrors 3 and 4 are deviated as described above, if the parallel relationship between the mirrors 3 and 4 is maintained, the laser light from the mirror 4 to the condenser lens 5 is The optical axis does not tilt, and only eccentricity occurs.

FIG. 9 is a perspective view showing the position detecting sensor 9. The optical section is divided into light receiving sections 9A and 9B. By comparing and calculating the intensities of light incident on the respective light receiving sections 9A and 9B, The tracking position is being detected. That is, the light focused on the light receiving portions 9A and 9B of the position detection sensor 9 is composed of the regular reflection light 15 of the track groove on the recording surface 13 of the optical disk 12 and the first-order diffracted light 16 and 17, and the light receiving portions 9A and 9B.
Interference on B produces spotlights 18, 19. The position detecting sensor 9 detects the tracking position by comparing and calculating the intensities of the spot lights 18 and 19.

[0011]

However, the track groove on the recording surface 13 of the optical disk 12 has an extremely narrow width, for example, only 1.6 microns. Therefore, spot light 18,1
The size of 9 is small, and therefore the position of the position detection sensor 9 and the optical system require a very precise positional relationship.

Particularly, in the mirrors 3 and 4 shown in FIG. 7, even if any one of the parallelism between them and the mounting angle of the arm 22 of the sliding / rotating member 2 with respect to the reference axis 20 is incorrect. , The optical axis center is eccentric and the light receiving portion 9 of the position detection sensor 9
Since the positions of the spotlights 18 and 19 on A and 9B deviate, accurate tracking position detection becomes impossible.

The spot light 18 due to this angle error,
The positional deviation of 19 cannot be dealt with only by adjusting the mounting position of the position detection sensor 9 by drawing a circle on the light receiving portions 9A and 9B of the position detection sensor 9 as the sliding rotation member 2 rotates.
In addition, the permissible accuracy of parallelism between the mirrors 3 and 4 is within several minutes in terms of angle, and the permissible accuracy of the deflection angle error r on the left and right with respect to the reference axis 20 and the tilt angle error θ on the upper and lower sides are each several degrees in angle. Within a minute and tough.

Actually, since a processing error of the mirror mounting surface of the sliding / rotating member 2 and a mirror mounting error at the time of assembly are added, it is extremely difficult to mount the mirror 3 and the mirror 4 which simultaneously satisfy the above accuracy. there were.

The present invention has an object of providing an extremely easy optical axis adjusting mechanism in view of the complexity of the optical axis adjustment of the conventional optical pickup described above.

[0016]

DISCLOSURE OF THE INVENTION The present invention is directed to a sliding center shaft fixed to a base member of an optical disk device and having an optical path in the shaft, and a lateral shaft having the optical path in the shaft supported by the sliding center shaft. And a sliding rotation member provided with a condenser lens for performing a focusing operation in a direction and a tracking operation in a rotating direction,
In the optical pickup that detects the reflected light from the recording surface of the optical disk by the position detection sensor and performs the tracking operation and the focus operation based on the detection output, the light collecting provided at one end of the arm of the sliding rotation member. The lens is movable so that the optical axis of the optical pickup is adjusted.

[0017]

According to the present invention, the position of the condenser lens is adjusted and attached to one end of the arm of the sliding and rotating member.
The optical axis can be adjusted easily and accurately.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an exploded perspective view of an essential part showing an embodiment of the present invention, and FIG. 2 is an enlarged exploded perspective view of a lens holder portion of FIG.

The mirror 4 with respect to the mirror 3 shown in FIG. 1 is adhered and fixed to one end of the arm 22 of the sliding / rotating member 2 while maintaining a parallel relationship therebetween. The condenser lens 5 shown in FIG. 2 is a lens holder whose bottom surface is smooth.
It is glued and fixed to 21. The lens holder 21 is arranged in alignment with the smooth surface of one end of the arm 22 of the sliding / rotating member 2,
The connection is fixed by adjusting to a position displaced by the amount of eccentricity ΔX / ΔY of the optical axis due to the mounting angle error Δr / Δθ of the mirror 3 and the mirror 4. As a result, even if the eccentricity Δr · Δθ is generated, the eccentricity of the optical axis on the position detection sensor 9, that is, the positional deviation of the spot lights 18 and 19 described in FIG. 9 can be suppressed.

FIG. 3 is an exploded perspective view of an essential part of another embodiment of the present invention, in which the mirror 4 is slidably rotated with respect to the mirror 3 not shown in the drawing while maintaining a parallel relationship therebetween. It is adhesively fixed to one end of the arm 22 of the member 2. The condenser lens 5 is adhered and fixed to a lens holder 21 having a collar with a width d. The spring 23 is an elastic member having a height of h, and the lens holder 21
It is fixed to. The spring 23 may be formed by bending the lens holder 21 using an elastic member.

The arm 22 of the sliding / turning member 2 has a width D and a spring sufficiently larger than the width d of the flange of the lens holder 21.
It has a groove 24 with a height H slightly narrower than the height h of 23. The lens holder 21 is inserted into the groove 24 of the arm 22 of the sliding / rotating member 2 from the direction of the arrow. At this time, the condenser lens 5 is inserted so that the center of the condenser lens 5 is displaced by the amounts of the eccentricities ΔX and ΔY of the optical axes due to the errors of the mounting angles r and θ of the mirrors 3 and 4. After insertion, the lens holder 21 is fixed in the groove 24 of the arm 22 of the sliding / rotating member 2 by the elasticity of the spring 23.

FIG. 4 is a perspective view of an example having a shape different from that of the lens holder of FIG.
This is a case where A is bent to have the same height as the height h of the spring 23 in FIG. 3, and is mounted and fixed in the groove of the arm 22 of the sliding and rotating member 2 in FIG.

[0023]

As described above, the optical axis alignment mechanism of the optical pickup according to the present invention is provided with the condenser lens whose position can be adjusted, so that the error in the mounting accuracy of the mirror in the optical path can be corrected. As a result, the yield is improved, the manufacturing cost is reduced, and the assembling property is improved.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of essential parts showing an embodiment of the present invention.

FIG. 2 is an enlarged exploded perspective view of a lens holder portion of FIG.

FIG. 3 is an exploded perspective view of essential parts showing another embodiment of the present invention.

FIG. 4 is a perspective view of an example having a different shape from the lens holder of FIG.

FIG. 5 is an exploded perspective view of essential parts showing a conventional shaft sliding type pickup.

6 is a cross-sectional view showing the optical system of FIG.

FIG. 7 is a schematic diagram of an optical system of the shaft sliding type pickup shown in FIG.

FIG. 8 is a schematic diagram of an optical system during rotation in FIG.

FIG. 9 is a perspective view showing a detection surface of a position detection sensor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Base member, 2 ... Sliding rotation member, 3, 4 ... Mirror, 5 ... Condensing lens, 21 ... Lens holder, 21A ... Corner, 22 ... Arm of sliding rotation member 2, 23 ... Spring, twenty four
…groove.

Claims (1)

[Claims] 1. A sliding center axis fixed to a base member of an optical disk device and having an optical path in the shaft, and a focus operation in the axial direction in which the optical axis is the optical axis supported by the sliding center shaft and in the rotational direction. A sliding rotation member provided with a condensing lens for performing a tracking operation is provided, the reflected light from the recording surface of the optical disc is detected by a position detection sensor, and the detection operation outputs the tracking operation and the focus operation. In the optical pickup, an optical axis alignment mechanism of the optical pickup, wherein a position of a condenser lens provided at one end of an arm of the sliding / turning member is movably configured to adjust an optical axis.