JPH079211Y2 - 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 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 on 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 of the condenser lens 1, as shown in FIG.
Is attached to the fixing member 9, and the fixing member 9 is moved and adjusted in the X and Y directions within a plane perpendicular to the optical axis with respect to the supporting member 6, and then the fixing member 9 is attached to the supporting member 6 with an adhesive or the like. Fix it.

Further, in order to obtain a spot of an appropriate size on the photodetector 3, the supporting member 6 must be adjusted in the Z direction parallel to the optical axis, but the supporting member 6 is as shown in FIG. Further, 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]

The present invention solves the above-mentioned problems of the conventional optical pickup device, and supports a photodetector that detects reflected light from a recording medium at an appropriate position by means that is simple, compact, and lightweight. At the same time, it is an object of the present invention to provide an optical pickup device that does not require another printed circuit board, a flexible printed circuit board or the like to be attached to a block that supports a photodetection block by using a metal substrate.

[Outline of device]

The present invention is intended to achieve the above-mentioned object, in which a surface parallel to the optical axis of the reflected light is formed on the photodetection block on which the photodetector of the reflected light is formed, and an insulating layer is formed on the metal plate. The gist is that the surface of the metal substrate on which the conductive pattern is formed is supported in surface contact with the via and the pattern of the photodetection block and the pattern of the metal substrate are connected by a bonding wire.

[Example of device]

Next, an example of the embodiment of the present invention will be described with reference to FIGS. 1 to 5, and the same portions corresponding to FIGS. 6 to 9 are designated by the same reference numerals.

As shown in FIG. 4 or FIG. 5, the photodetector 3 has two reference planes 52 and 53 which are parallel to the optical axis of the condenser lens that focuses the reflected light from the disc and are orthogonal to each other. It is fixed to the photodetection block 51 that it has, and its output is led to the outside by a conductive pattern 63 formed on the surface of the detection block 51.

The metal substrate 41 on which the reference surfaces 42 and 43 which come into surface contact with the reference surfaces 52 and 53 of the light detection block 51 are formed is formed on one surface of an aluminum plate 44 having a thickness of 1 to 2 mm as shown in FIG. 50-150 μm
Epoxy-based insulation layer 45 is formed and the thickness on it
A copper foil 46 having a thickness of 10 to 35 μm is formed.

A circuit pattern is formed on the copper foil 46 by etching, and an aluminum foil 47 for bonding, such as aluminum 40 μm, is provided in a portion near the reference surface 42 of the copper foil 46.

The middle part of the pattern of the copper foil 46 is solder resist.
It is covered with 48, and the side opposite to the aluminum foil 47 becomes the lead lead-out portion.

In such a metal substrate 41, as shown in FIG. 3, an insulating layer 45, a pattern of a copper foil 46, an aluminum foil 47, and a solder resist 48 are formed at many places on a single aluminum plate 44. It is formed by punching this into a desired shape.

The reference surfaces 42 and 43 of the metal substrate 41 and the reference surfaces 52 and 53 of the light detection block 51 are brought into contact with each other, and the other end of the leaf spring 71 having one end fixed to the metal substrate 41 is brought into contact with the light detection block 51. 52 is pressed against the reference surface 42 and the reference surface 53 is pressed against the reference surface 43.

Then, the aluminum foil 47 and the pattern 63 of the photodetecting chip 10 are connected by a bonding wire 64, and the lead lead portion of the copper foil 46 is connected with a lead wire such as a flexible printed circuit board reaching the servo circuit 28. It is a thing.

The metal substrate 41 is attached to the housing 26,
At the time of mounting, the position of the photodetector 3 is adjusted in the X and Y directions so that the center thereof coincides with the optical axis of the condenser lens 1.

Next, the light detection block 51 is pressed against the reference surface by the pressing force of the leaf spring 71.
The position is adjusted in the Z direction while keeping 42 and 52, 43 and 53 in contact with each other so that the spot formed on the surface of the photodetector 3 has an appropriate size.

Then, they are adhered by a method such as pouring an instant adhesive between the reference surfaces 42 and 52 and 43 and 53.

The adjustment of the movement of the light detection block 51 in the Z direction with respect to the metal substrate 41 can be performed without difficulty due to the flexibility of the bonding wire 64.

The pressing of the leaf spring 71 against the light detection block 51 according to this embodiment is performed by fixing both ends of the leaf spring 71 to the metal substrate 41 and pressing the central bent portion 72 to the light detection block 51 as shown in FIG. You may go by.

Alternatively, as shown in FIG. 5, the central portion of the leaf spring 71 having the bent portions 73 and 74 formed at both ends may be fixed to the metal plate 41, and the bent portions 73 and 74 may be pressed against the light detection block 51. It is a thing.

[Effect of device]

As described above, in the present invention, since the photodetector is provided in the photodetection block without using a mold, the leadframe for molding is eliminated and the photodetection block can be made smaller and lighter.

Further, since the metal substrate is used as a block that supports the light detection block, it is not necessary to attach a printed circuit board or a flexible printed circuit board to the block, and the metal substrate can serve as an adjustment block of the light detection block and a relay substrate. .

By combining these two factors, it is possible to reduce the size and weight of the optical pickup device, reduce the currents for focus control and tracking error control for that purpose, and reduce the cost.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention, FIG. 2 is a sectional view of a metal substrate, FIG. 3 is a perspective view showing the manufacturing process thereof, and FIGS. A front view, FIG. 6 is a block diagram of an optical pickup device, FIGS. 7 and 8 are oblique views of a conventional photodetector, and FIG. 9 is a front view thereof. 3 ... Photodetector, 26 ... Housing, 41 ... Metal substrate, 42, 43
...... Reference plane, 44 ...... Aluminum plate, 45 …… Insulation layer, 46 …… Copper foil, 47 …… Aluminum foil, 48 …… Solder resist, 51 …… Light detection block, 52,53 …… Reference plane, 63 …… Pattern, 64
...... Bonding wire.

Claims (1)

[Scope of utility model registration request] 1. A photodetector for detecting reflected light from a recording medium, and a pattern connected to the photodetector for deriving an output of the photodetector. The pattern is parallel to the optical axis of the reflected light from the recording medium. A light detection block having a surface and a support surface in surface contact with a surface parallel to the optical axis of the light detection block are provided, and the support surface can be moved in two directions orthogonal to the optical axis, and on the metal main plate. An optical pickup device comprising: a metal substrate on which a conductive pattern is formed via an insulating layer; and a bonding wire that connects the pattern of the metal substrate and the pattern of the photodetection block.