JPH0329773Y2 - - 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 has been developed by focusing on the above-mentioned conventional problems, and is an optical system that has a compact structure and can perform highly accurate adjustment of the focal length of the light receiving element and optical axis alignment in an optimal state. The object of the present invention is to provide a photodetector adjustment device for a type pickup.

[Structure of the present invention]

In the light-receiving element adjustment 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 connected to each other, the slider is formed with an optical axis path that communicates with the optical axis of the optical system, and an adjustment spacer is located on the slider at a position aligned with the optical axis path that connects the optical axis. The adjustment spacer is screwed so that it can move forward and backward along the axial direction of the passage, and a mounting plate is abutted against the base end of the adjustment spacer, and a light receiving element is fixed to the mounting plate facing the optical axis passage. A fixing screw inserted through the mounting plate is screwed into the slider through a hollow portion formed in the adjustment spacer, and the focal length of the light receiving element is is adjusted by moving the adjustment spacer 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.

[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 feature 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 sectional plan view of the slider. , FIG. 5 is a plan view of the main parts 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 lenses 3a
The optical axes of ~3c and the prism 4 have already been adjusted when they are assembled to the lens holder 17.

Further, a concave lens 3d is bonded in the reflection direction of the beam splitter 3a. Further, the slider 14 is provided with an optical axis passage 14a extending on the optical axis of the concave lens 3d. A cylindrical lens 3e is mounted within this optical axis passage 14a. This cylindrical lens 3e is held and attached to a holder (not shown).

A hole parallel to the optical axis passage 14a is screwed in a position lined up with the optical axis passage 14a, and inside this hole is a large diameter female threaded part 14c into which the adjustment spacer 18 is screwed, and behind it a large diameter female threaded part 14c. A continuous small-diameter female screw portion 14d is formed. A fixing screw 21 is screwed into this small diameter female threaded portion 14d.

A hollow portion 18a is formed in the axial center of the adjustment spacer 18. Further, a male screw 18b is screwed at the tip of the adjustment spacer 18, and a flange 18b is screwed at the base.
c is formed. A plurality of grooves 18e into which tools are engaged are formed at equal intervals on the outer periphery of the flange 18c. Alternatively, the side surface of the flange 18c may be formed into a hexagonal surface so that the flange 18c can be rotated with a hexagonal wrench.

Further, a mounting plate 19 made of a magnetic material is in contact with the upper surface of the flange 18c. A relatively large-diameter escape hole 19b is bored in one side of the mounting plate 19 and communicates with the hollow portion 18a formed in the adjustment spacer 18. Further, on both sides of the mounting plate 19, locking holes 19c are formed into which pins 22c of an adjustment jig 22, which will be described later, are fitted.

Furthermore, on the front side of this mounting plate 19 and in the escape hole 19
A flexible substrate 20 is fixed to the side of b by adhesive or other means. This flexible board 20
A light-receiving element 7 is soldered to the cylindrical lens 3e, and the light-receiving element 7 faces the optical axis passage 14a formed in the slider 14 and faces the cylindrical lens 3e (see FIG. 3).

As shown in FIG. 3, the escape hole 1 of the mounting plate 19 is
A fixing screw 21 is inserted through 9b, and this fixing screw 21 penetrates the hollow portion 18a of the adjustment spacer 18 and is screwed into the female threaded portion 14d of the slider 14.

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 the adjustment jig 22 is attached to this spring 2.
3 in the direction of the arrow. Further, the front surface of the adjustment jig 22 is a flat portion 22b. A magnet (not shown) is attached to this flat portion 22b, and a mounting plate 19 is attached to this flat portion 22b.
A pin 22c is provided protrudingly to be fitted into the latching hole 19c.

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

First, the slider 14 is set on the jig stand. The light emitting element 2, the optical system 3 attached to the lens holder 17, and the prism 4 are assembled in advance on the slider 14. Further, a male screw 18b of the adjustment spacer 18 is screwed into a female screw portion 14c screwed onto the slider 14.

The adjustment jig 22 is placed opposite to the surface of the slider 14 on which the optical axis passage 14a is exposed, and the mounting plate 19 is mounted by a magnet on the flat portion 22b of the adjustment jig 22. At this time, the locking hole 19c drilled in the mounting plate 19 is fitted into the pin 22c of the adjustment jig 22, and the mounting plate 19 and the adjustment jig 22 are positioned.

The adjustment jig 22 is advanced toward the adjustment spacer 18 by the biasing force of the spring 23, and the mounting plate 19
is brought into pressure contact with a flange 18c formed at the base of the adjustment spacer 18.

A groove 18e formed in the flange 18c
engage the tool to rotate the adjusting spacer 18. The adjustment spacer 18 is moved forward and backward by the screw engagement between the male screw 18b and the female screw 14c, and at the same time, the light receiving element 7 is also moved forward and backward together with the mounting plate 19 which is pressed against the flange 18c. Meanwhile, the light receiving element 7
The input of the laser beam is detected by a monitor, etc., and the cylindrical lens 3 of the light receiving element 7 is detected.
Adjust the focal length for e.

In addition, when the adjustment jig 22 is moved two-dimensionally in a direction perpendicular to the optical axis little by little using a micrometer or the like, the adjustment jig 22 can be attached via the latch hole 19c that fits into the pin 22c of the adjustment jig 22. The plate 19 moves slightly, and the light receiving element 7 also moves with the movement. and,
The input of the laser beam incident on 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 alignment of the light-receiving element 7 are adjusted by three-dimensionally moving the light-receiving element 7 itself.

After this adjustment work is completed, the fixing screw 21 is loosely inserted into the relief hole 19b of the mounting plate 19, and the fixing screw 21 is inserted into the hollow part 18a of the adjustment spacer 18.
The mounting plate 19 is fixed to the slider 14 by passing through it and screwing into the female screw portion 14d of the slider 14. Of course, although not shown, the adjustment jig 22 has an escape hole through which a tool for rotating the fixing screw 21 is inserted.

Although this mounting plate 19 is fixed to the slider 14 only by one fixing screw 21, for example, if this mounting plate 19 is installed in a place where it can be hidden from the outside, it can be easily secured while the product is being transported. In addition, there is no possibility that the mounting plate 19 will be accidentally rotated during assembly. Alternatively, the mounting plate 19 may be fixed to the slider 14 together with the adjustment spacer 18 and the fixing screw 21 by applying adhesive.

Also, fix the mounting plate 19 to the slider 14 with the screw 2.
The flat part 22b is temporarily fixed in advance through the mounting plate 1, and the adjustment jig 22 is brought close to it from behind, and the flat part 22b is attached to the mounting plate 1.
9 and fitting the pin 22c into the locking hole 19c, the adjustment work as described above may be performed.
In this case, the adjustment work can be performed without providing a magnet on 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 attached to the mounting plate 1.
Although it is fixed to the front surface of the mounting plate 9, it may be fixed to the back surface of the mounting plate 19. In this case, it is necessary to provide an escape hole in the mounting plate 19 and the flexible substrate 20 for transmitting the laser beam.

[Effects of this invention]

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

(1) An adjustment spacer is screwed onto the slider that moves along the recording surface of the disk so that it can move forward and backward, a mounting plate is brought into contact with the base end of the adjustment spacer, and the light-receiving element is fixed to this mounting plate. Because
The focal length of the light receiving element relative to the optical system installed on the slider can be adjusted by moving the adjustment spacer forward and backward, and the optical axis alignment can be adjusted by moving the mounting plate two-dimensionally in a direction perpendicular to the optical axis. can. Therefore, even in an optical pickup having a structure in which a concave lens 3d is bonded to a beam splitter 3a as shown in FIG. 4, the mounting position of the light receiving element can be easily and reliably adjusted.

(2) In particular, the focal length is adjusted using an adjustment spacer, the optical axis is aligned by moving the mounting plate, and adjustments in each direction are performed using separate members. Therefore, delicate adjustments in each direction can be made independently and reliably.

(3) Since the screw that fastens the mounting plate passes through the hollow part drilled in the adjustment spacer and is screwed into the slider, both screws have a common part.
The device becomes more compact.

[Brief explanation of drawings]

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, 18...Adjustment spacer, 18a...
Hollow part, 19...Mounting plate, 21...Fixing screw, 2
2...Adjustment jig.

Claims (1)

[Scope of utility model registration request] In an optical pickup, 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. The slider is formed with an optical axis passage that communicates with the optical axis of the optical system, and an adjustment spacer is provided at a position of the slider in line with the optical axis passage so that it can move back and forth along the axial direction of the optical axis passage. A mounting plate is in contact with the base end of this adjustment spacer, and a light receiving element is fixed to this mounting plate facing the optical axis passage, and the light receiving element is inserted through this mounting plate. A light-receiving element adjustment device for an optical pickup, characterized in that a fixing screw is screwed into the slider through a hollow portion bored in the adjustment spacer.