JPH0329772Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field] The present invention relates to an optical pick-up for reading information recorded on a recording surface of a compact disc, etc., and in particular, it is concerned with setting the focal length of the optical system of the light-receiving element and aligning the optical axis. The present invention relates to a light receiving element adjusting device for performing the above.

[Technical background and conventional technology]

The operating principle of the optical pickup will be explained with reference to FIG.

The optical pickup 10 is mounted on a slider (not shown) that moves along the recording surface 1a of the compact disc 1.

The laser beam emitted from the light emitting element 2 is passed through a beam splitter 3a, a collimating lens 3b, and a 1/4
It reaches the prism 4 via the wave plate 3c. The laser beam reflected by the prism 4 is focused by an objective lens 9 and then irradiated onto the recording surface 1a of the compact disc 1.

The beam reflected from the recording surface 1a then returns to the objective lens 9 and follows the opposite path to the beam splitter 3a. Here, the beam is reflected in the right angle direction and is detected by the light receiving element 7 through the concave lens 3d and the cylindrical lens 3e. The light receiving element 7 detects the presence or absence of pits P formed as digital information on the recording surface 1a, and reads the information.

[Problems with conventional technology]

In this type of optical pickup 10, the optical axis position of the laser beam incident on the light receiving element 7, the incident angle of the optical axis, and the focal position of the laser beam are as follows.
There are some three-dimensional variations due to the influence of assembly errors of the optical system 3 made up of members 3a to 3e such as lenses. Therefore, it is necessary to adjust the alignment of the light receiving element 7 with respect to this optical axis.

Conventionally, the optical axis alignment of the above alignment adjustment of the light receiving element 7 with respect to the optical system 3 has been adjusted by two-dimensionally moving a holder holding the light receiving element 7 in a direction perpendicular to the optical axis. was. Further, the focus of the laser beam on the light receiving element 7 is adjusted by moving the cylindrical lens 3e or the concave lens 3d back and forth along the optical axis.

However, there is a trend in recent audio equipment to become smaller and thinner, and some optical pickups 10 also have a structure in which a concave lens 3d is bonded to a beam splitter 3a in order to respond to this trend toward smaller and thinner devices. According to this structure, the focal length of the light receiving element 7 cannot be adjusted by the concave lens 3d. Therefore, it is necessary to move the holder containing the light-receiving element 7 three-dimensionally in the optical axis direction and the direction orthogonal to the optical axis, but it is necessary to move one holder three-dimensionally. In the method,
This has the disadvantage that delicate adjustments in each direction are extremely difficult.

[Purpose of this invention]

The present invention was developed by focusing on the above-mentioned conventional problems, and is an optical pick-up that has a compact structure and can finely and optimally adjust the focal length of the light-receiving element and the optical axis alignment. The present invention aims to provide a light-receiving element adjusting device.

[Structure of the present invention]

In the light-receiving element adjusting device of the present invention, an objective lens facing the recording surface is provided on a slider that moves along the recording surface of the disk, and a light-emitting element and a light-receiving element are connected to this objective lens through an optical system. In the optical pickups that are arranged in series, the slider is formed with a guide hole located on the optical axis of the optical system, and a spacer with a shaft hole formed in the guide hole is arranged in the direction of the optical axis. A mounting plate is abutted against the base end of the spacer, and a light-receiving element facing in the shaft hole of the spacer is fixed to the mounting plate. It is. The focal length of the light-receiving element is adjusted by rotating the spacer and moved back and forth, and the optical axis alignment is adjusted by moving the mounting plate two-dimensionally in a direction perpendicular to the optical axis. By performing these adjustments in each direction separately, delicate adjustment work can be reliably performed.

[Example of the present invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to FIGS. 1 to 3 and FIG. 5.

Fig. 1 is an exploded perspective view of part A in Fig. 3 showing the light-receiving element adjusting device which is a characteristic part of the present invention, Fig. 2 is a plan view showing the operation of the light-receiving element adjusting device, and Fig. 3 is a cross-sectional plane of the slider. FIG. 5 is a plan view of the main part of the disk player.

(Principle of operation of disk player) First, the operation of the disk player will be explained with reference to FIG.

When the spindle shaft 12 installed upright on the chassis 11 rotates, this spindle shaft 12
A compact disc 1 set on a turntable 13 rotates.

Recording surface 1a (fourth
(see figure), an objective lens 9 faces the lens 9 with a predetermined distance therebetween. This objective lens 9 forms a part of an optical pickup 10, and this optical pickup 10 is mounted on a slider 14. Both sides of the slider 14 are slidably supported by guide shafts 15a and 15b fixed to the chassis 11 via bearings 16.

The slider 14 moves in synchronization with the rotation of the spindle shaft 12 from the side shown by the dashed line in the drawing in the direction shown by the solid line. During this time, the optical pickup 10 reads the information recorded on the recording surface 1a as described above with reference to FIG.

(Description of Features) As shown in FIG. 3, the optical pickup 10 mounted on the slider 14 has a light emitting element 2 attached to one side of the slider 14, and a beam splitter 3a of the optical system 3, Collimator lens 3b
The 1/4 wavelength plate 3c and the prism 4 are attached to the lens holder 17. Each of these optical elements 3
The optical axes of a to 3c and the prism 4 are connected to the lens holder 17
It has already been adjusted when it is assembled.

Further, a concave lens 3d is bonded in the reflection direction of the beam splitter 3a. The slider 14 has a guide hole 14a located on the optical axis of the concave lens 3d.

A cylindrical lens 3e is mounted inside this guide hole 14a. This cylindrical lens 3e is attached to the guide hole 14 by an independent holder.
a, or may be held within a spacer 18, which will be described later. Alternatively, the cylindrical lens 3e may be attached continuously to the concave lens 3d. Also, this guide hole 14
A female thread 14b is screwed in the middle of a, and a reference hole 14c is bored near the exit of the female thread 14b.

Furthermore, a spacer 18 is screwed into the guide hole 14a from the exit side, as shown in FIGS. 1 and 2. Inside this spacer 18 is a shaft hole 1.
8a is formed. Further, a male thread 18b is screwed onto the tip of the spacer 18, a flange 18c is formed at the base, and a shaft portion 18d is formed between the male thread 18b and the flange 18c.
The male screw 18b is screwed into the female screw 14b, and the shaft portion 18d is slidably fitted into the reference hole 14c without any gap. In addition, the flange 18
A plurality of grooves 18e into which tools are engaged are formed at equal intervals on the outer periphery of c. Note that instead of this groove 18e, the side surface of the flange 18c may be formed into a hexagonal surface so that it can be rotated with a hexagonal wrench.

A mounting plate 19 made of a magnetic material is in contact with the surface of the flange 18c. This mounting plate 19 has a shaft hole 1 bored in the spacer 18.
A hole 19a that communicates with 8a is drilled, and mounting holes 19b are drilled on both sides of the hole 19a. This mounting hole 1
9b has a relatively large diameter, and a screw hole 14d corresponding to this mounting hole 19b is attached to the slider 1.
4 is screwed. Furthermore, this mounting hole 19b
A latching hole 19c is bored in the upper direction.

A flexible board 2 is attached to the back of this mounting plate 19.
0 is fixed by adhesive or other means. A light receiving element 7 is soldered to this flexible substrate 20. Although not shown, a hole is formed in the flexible substrate 20 to allow the laser beam to pass through the light receiving element 7, and the light receiving element 7 is electrically connected to the cylindrical lens 3e through this hole.

As shown in FIG. 3, a mounting screw 21 is inserted through the mounting hole 19b of the mounting plate 19, and this mounting screw 21 is screwed into the threaded hole 14d of the slider 14. In addition, the mounting hole 19b and mounting screw 2
A gap is formed between the mounting plate 19 and the optical axis 1, so that the mounting plate 19 can move by this gap in a direction perpendicular to the optical axis.

Further, the reference numeral 22 shown in FIG. 4 is an adjustment jig provided on a jig stand (not shown). On both sides of this adjustment jig 22 are springs 2 extending from the jig stand.
3 is hooked, and this adjustment jig 22 is attached to the spring 2.
3 in the direction of the arrow.

In addition, a recess 22a for escaping the light receiving element 7 and a mounting screw 21 are provided at the center of the front surface of the adjustment jig 22.
A hole (not shown) communicating with the head is formed. The periphery of the recessed portion 22a is a flat portion 22b. A magnet (not shown) is attached to this flat portion 22b, and a pin 22c that is fitted into a hook hole 19c of the mounting plate 19 is provided in a protruding manner.

(Operation of the embodiment) Next, the adjustment work of the optical axis and focal length of the light receiving element 7 will be explained.

First, the slider 14 is set on the jig stand. The light emitting element 2 and the optical system 3 and prism 4 attached to the lens holder 17 are assembled in advance on the slider 14. Guide hole 1 of this slider 14
A spacer 18 is screwed onto 4a.

Then, the adjustment jig 22 is opposed to the surface of the slider 14 into which the spacer 18 is screwed, and the adjustment jig 22 is
The mounting plate 19 is attracted to a magnet provided on the flat surface 22b of 2. At this time, the pin 22c of the adjustment jig 22 is fitted into the latch hole 19c, and the mounting plate 19
and the adjustment jig 22 are positioned. Further, the adjustment jig 22 is advanced toward the spacer 18 by the biasing force of the spring 23, and the mounting plate 19 is brought into pressure contact with the flange 18c of the spacer 18.

Then, a tool such as a wrench is engaged with the groove 18e of the flange 18c to rotate the spacer 18. This spacer 18 has a male thread 18b and a female thread 1.
It moves forward and backward by screwing with 4b. The shaft portion 18d of this spacer 18 is connected to the reference hole 14 of the guide hole 14a.
c, the above-mentioned forward and backward movements are performed linearly. During this time, the laser beam input to the light receiving element 7 is detected by a monitor or the like, and the focal length of the light receiving element 7 with respect to the cylindrical lens 3e is adjusted.

Further, the adjustment jig 22 is slightly moved two-dimensionally in a direction perpendicular to the optical axis using a micrometer or the like. Then, pin 2 of this adjustment jig 22
The mounting plate 19 is inserted through the latch hole 19c that fits into the mounting plate 2c.
moves slightly, and the light receiving element 7 follows the movement. Then, the laser beam input to the light-receiving element 7 is detected by a monitor or the like, and the light-receiving element 7 is adjusted so as to be aligned with the optical axis of the laser beam.

As described above, the focal length and optical axis of the light receiving element 7 are adjusted by three-dimensionally moving the light receiving element 7 itself. After this adjustment work is completed, loosely insert the mounting screw 21 into the mounting hole 19b of the mounting plate 19, screw the mounting screw 21 into the threaded hole 14d of the slider 14, and attach the mounting plate 19 to the slider 14.
Fixed to.

In addition, the slider 14 is temporarily attached to the mounting plate 19 using the mounting screws 21 in advance, and the adjustment jig 22 is brought close to the mounting plate 19 from behind, the flat part 22b is brought into contact with the mounting plate 19, and the pin 22c is inserted into the latching hole. After fitting into 19c, the above-mentioned adjustment work may be performed. In this case, the adjustment work can be performed without attaching a magnet to the flat portion 22b of the adjustment jig 22.

Note that the light receiving element 7 according to the embodiment shown in the figure is mounted on the mounting plate 1.
Although it is fixed to the back surface of the mounting plate 9, it may be fixed to the front surface of the mounting plate 19. In this case, a hole is made in the flange 18c of the spacer 18 to allow the light receiving element 7 to escape.

[Effects of this invention]

As described above, according to the present invention, the following effects can be achieved.

(1) A spacer is screwed onto the slider that moves along the recording surface of the disk, and a mounting plate is in contact with the base end of this spacer, and the light receiving element is fixed to this mounting plate. By moving the spacer back and forth, the focal length of the light receiving element can be adjusted, and by moving the mounting plate in a direction perpendicular to the optical axis, the optical axis can be aligned. Therefore, even in an optical pickup having a structure in which the concave lens 3d is fixed to the beam splitter 3a as shown in FIG. 4, the focal length can be easily and reliably adjusted.

(2) In particular, a spacer and a mounting plate are provided separately, and alignment in the optical axis direction is performed using the spacer.
Since alignment in the direction perpendicular to the optical axis is performed using the mounting plate, adjustment in each direction is performed separately. Therefore, delicate adjustments in each direction are possible, making adjustment work easier.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, FIG. 1 is an exploded perspective view of part A in FIG. 3 showing the light receiving element adjustment device, and FIG. 2 shows the operation of the light receiving element adjustment device. 3 is a sectional plan view of the slider, FIG. 4 is a principle diagram showing the operation of the optical pickup, and FIG. 5 is a plan view of the main parts of the disk player. DESCRIPTION OF SYMBOLS 1... Disk, 1a... Recording surface, 2... Light emitting element, 3... Optical system, 7... Light receiving element, 9... Objective lens, 10... Optical pickup, 14...
...Slider, 14a...Guide hole, 18a...Shaft hole, 18...Spacer, 19...Mounting plate, 22...
...Adjustment jig.

Claims (1)

[Scope of utility model registration request] In an optical pick-up, an objective lens facing the recording surface is provided on a slider that moves along the recording surface of a disk, and a light emitting element and a light receiving element are connected to this objective lens via an optical system. A guide hole located on the optical axis of the optical system is formed in the slider, and a spacer having a shaft hole is screwed into the guide hole so as to be movable forward and backward in the optical axis direction. ,
A light-receiving element adjusting device for an optical pickup, characterized in that a mounting plate is brought into contact with the base end of the spacer, and a light-receiving element facing the spacer is fixedly mounted on the mounting plate.