JPH0643852Y2 - Optical pickup device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is used in optical video disc players, audio disc players, optical disc devices, etc., and is included in the light reflected from these discs. The present invention relates to an optical pickup device for reading a signal.

[Conventional technology]

An outline of a conventional optical pickup device of this type is shown in FIG.

In this optical pickup device, the monitor light output from the semiconductor laser chip 20 is detected by the photodetector 25,
The servo circuit 28 compares the output of the detector 25 with a predetermined reference value and drives the semiconductor laser chip 20 in accordance with the difference signal so that the output light of the semiconductor laser chip 20 has a constant level.

The output light of this semiconductor laser chip 20 is reflected by the surface of the plane-parallel plate 23, enters the objective lens 24, and
Disk 21 which is focused by this and rotated by a motor 22
Irradiate on.

The light beam reflected by the disk 21 contains the signal recorded on the disk 21, is condensed by the objective lens 24 and is incident on the plane-parallel plate 23, but is refracted on the surface thereof and reflected on the back surface. Upon exiting the plane-parallel plate 23, it is refracted again at the surface.

Then, the light is incident on the photodetector 3 including a photodiode or the like. Since the photodetector 3 can extract the signal contained in this light as an electric signal, the disc
Can play 21 signals.

The light incident on the photodetector 3 is given astigmatism by refraction when passing through the plane-parallel plate 23, and the servo circuit 27 generates and outputs a focus error signal by the astigmatism method. A drive signal corresponding to the focus error signal is output to the coil 29 forming the actuator.

The coil 29 is wound around a housing 26 to which the semiconductor laser chip 20, the photodetector 25, the plane parallel plate 23, the objective lens 24, and the photodetector 3 are attached, and is positioned in the magnetic field of the magnetic circuit 30. Therefore, the housing 26 is driven in response to the focus error signal, and the housing 26 is maintained at the focus position.

In such a case 26, the photodetector 3 is not
As shown in the figure, the light reflected by the disk 21 is condensed by the condenser lens 1 and enters the photodetector 3.

The photodetector 3 is molded in the mold 2 together with the lead frame 4 as shown in FIGS. 8 and 9, and the lead frame 4 and the photodetector 3 are bonded together with the bonding wire 7
, And the output of the photodetector 3 is led to the lead frame 4.

The lead frame 4 is soldered to the flexible substrate 5 and its output is guided to a required circuit.

Since the center of the photodetector 3 is aligned with the optical axis 1 of the condenser lens 1, the mold 2 of the photodetector 3 is attached to the fixing member 9 as shown in FIG. 6
On the other hand, after moving and adjusting in the X and Y directions in a plane perpendicular to the optical axis, the fixing member 9 is fixed to the supporting member 6 with an adhesive or the like.

Further, in order to obtain a spot of an appropriate size on the photodetector 3, the support member 6 must be adjusted in the Z direction parallel to the optical axis 6, but the support member 6 is shown in FIG. As described above, the support member 6 is movable in the Z direction with respect to the guide member 8, and the adjusted support member 6 is fixed to the guide member 8 with an adhesive or the like.

[Problems to be solved by the device]

Thus, in the conventional device, the photodetector 3 is provided, the fixing member 9 to which the mold 2 with the lead frame 4 protruding is attached to the supporting member 6, and the supporting member 6
Must be adjustable to the housing 26, and the mold 2 must be adjustable to the fixing member 9 and the fixing member 9 to the supporting member 6.

Therefore, since the shape of the support member 6 cannot be reduced, the housing
The 26 could not be downsized, and the entire optical pickup device could not be downsized.

[Purpose of device]

An object of the present invention is to solve the above problems of the conventional device and to reduce the size and weight of the support member, thereby reducing the size and weight of the entire optical pickup device.

[Outline of device]

In order to achieve the above object, the present invention provides a photodetector for detecting reflected light from a recording medium and a pattern thereof, and a translation block having a surface parallel to an optical axis of the reflected light, and An orthogonal movement member that has a surface in contact with a surface, is movable in a direction perpendicular to the optical axis, and has a flexible printed circuit board fixed, and a thin electric wire that connects the flexible printed circuit board and a pattern.

[Example of device]

Next, an embodiment of the present invention will be described with reference to FIG.
The same portions corresponding to FIGS. 6 to 9 are designated by the same reference numerals.

The photodetector 3 and the parallel movement block 51 to which the substrate 10 on which the pattern 63 connected to the photodetector 3 is formed are fixed are arranged with respect to the optical axis of the reflected light from the disc.
Two reference planes 52 and 53 that are parallel to each other and are orthogonal to each other are formed.

The orthogonal movement block 41 is provided with reference planes 42 and 43 which are in planar contact with the reference planes 52 and 53 and which support the parallel movement block 51 so as to be movable in the optical axis, that is, the Z direction.

Further, the orthogonal movement block 41 is provided with a leaf spring 71,
This leaf spring 71 is in contact with the translation block 51, and its reference plane
52 and 53 are pressed against the reference surfaces 42 and 43.

Therefore, by sliding the reference surfaces 52 and 53 with respect to the reference surfaces 42 and 43, the parallel movement block 51 can move in the optical axis direction of the reflected light, that is, the Z direction in FIG.

On the other hand, the orthogonal moving block 41 serving as the base can be moved and adjusted in the X and Y directions of FIG. 1 with respect to the housing 26 of FIG.
It is fixed with an epoxy adhesive that has a heat resistance of ~ 200 ° C.

Then, with the pattern 62 of the flexible printed circuit board 61,
The pattern 63 on the substrate 10 is connected by a bonding wire 64.

By moving the reference planes 52, 53 with respect to the reference planes 42, 43 in the Z direction, the spot size of the reflected light formed on the photodetector 3 is made appropriate, and then the reference planes 42, 43. The parallel movement block 51 is fixed to the orthogonal movement block 41 by a method such as pouring an instant adhesive between the reference planes 52 and 53.

Since the bonding wire 64 can be bent freely for this adjustment and fixing, there is no problem.

Next, the orthogonal movement block 41 is moved in the X and Y directions with respect to the housing 26 to match the center of the spot of the reflected light with the center of the photodetector 3, and then the orthogonal movement block 41 and the housing 26. Is fixed by an epoxy adhesive or the like similar to the above.

Even if both ends of the leaf spring 71 are fixed to the orthogonal movement block 41 and the central bent portion 72 is pressed against the parallel movement block 51 as shown in FIG. Good.

Alternatively, as shown in FIG. 3, bent portions 73 and 74 formed at both ends
May be pressed.

4 and 5 show another embodiment of the present invention, in which the translation block 51 has a cylindrical reference surface 52, and the orthogonal movement block 41 has a reference surface 42 formed in a cylindrical surface for receiving the reference surface. Has been done.

Further, a groove 81 is formed in the parallel movement block 51, and a leaf spring 71 having a curved shape is accommodated in the groove 81, and the parallel movement block 51 is pressed against the orthogonal movement block 41 by its pressing, and the Z direction of FIG. It is possible to move to.

Similarly, the orthogonal movement block 41 is also movable with respect to the housing 26 in the X and Y directions in FIG.

[Effect of device]

As described above, according to the present invention, the photodetector and the pattern connected to the photodetector are formed on the translation block that moves in parallel with the optical axis of the reflected light. It is not necessary to mold the lead frame with resin.

Then, fix one end of the flexible printed board to an orthogonal movement block that can move in a direction perpendicular to the optical axis of the reflected light,
Since this and the pattern are connected by a thin electric wire such as a bonding wire, the translation block can be adjusted in the Z direction without any trouble.

Furthermore, the mold of the photodetector is not required and the parallel movement block can be adjusted, so that the size and weight of the entire device can be reduced, and the current for focus control and tracking control can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention, FIGS. 2 and 3 are front views of the same leaf spring shape modification, and FIGS. 4 and 5 are perspective views and sectional views of another embodiment. FIG. 6 is a block diagram of an optical pickup device, FIGS. 7 and 8 are perspective views of a conventional photodetector, and FIG. 9 is a front view thereof. 3 ... Photodetector, 26 ... Housing, 41 ... Orthogonal movement block, 42, 43 ... Reference plane, 51 ... Parallel movement block, 52, 53
…… Reference plane, 61 …… Flexible printed circuit board, 62,63
…… Pattern, 64 …… Bonding wire.

Claims (1)

[Scope of utility model registration request] 1. A photodetector for detecting light reflected from a recording medium and a pattern for deriving an output of the photodetector are formed, and a surface parallel to the optical axis of the reflected light from the recording medium is provided. A parallel moving block and a surface in contact with a surface parallel to the optical axis of the parallel moving block, the movable block being movable in two directions orthogonal to the optical axis of the reflected light from the recording medium, An optical pickup device comprising an orthogonal movement block having one end fixed thereto, and a thin electric wire electrically connecting the flexible printed circuit board and the pattern of the parallel movement block.