JP2001266387A - Optical pickup - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical pickup capable of improving a heat radiating effect of a laser unit without increasing the number of parts and a working time. SOLUTION: The optical pickup is provided with the laser unit 1 having a laser being a light source, a superimposed circuit 2 for reducing an influence by return light to the laser from a disk, a shield casing 4 for interrupting unnecessary radiation from the superimposed circuit 2, and an optical pedestal 5 for fixing the laser unit 1 and also arranging optical parts. Projected shapes 4a, 4b, 4c are provided in the inside of the shield casing 4, and heat radiated from the laser unit 1 is radiated by bringing the projected shapes into contact with the laser unit 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup used in an optical disk recording / reproducing apparatus for recording and reproducing a signal on a disk by projecting a laser beam onto the disk.

[0002]

2. Description of the Related Art An optical pickup focuses laser light emitted from a laser light source on a disk with an objective lens.
The light corresponding to the signal waveform on the disk is received by a light receiving element, converted into an electric signal, and transmitted to an external electric circuit.

Hereinafter, an example of the vicinity of a laser unit which is a conventional light emitting unit will be described with reference to the drawings.

FIG. 5 is a side sectional view of the vicinity of a laser unit in a conventional optical pickup, and FIG. 6 is a sectional view taken along line XX of FIG.

In FIG. 5, reference numeral 51 denotes a laser unit having a laser 51a for emitting laser light and a light receiving element 51b for converting return light into an electric signal, a ground plane 51c inside, and a resin 51d surrounding the package. Have been. 51e is a cover for protecting the laser 51a and the light receiving element 51b. In this laser unit 51, a metal terminal 51f is connected to a flexible printed circuit board (hereinafter referred to as F).
By soldering 53 a to PC) 53, electrical connection is made, and it is arranged on FPC 53. In the FPC 53, the laser unit 5 is connected to the cover 51e on the light emitting surface side of the laser unit 51 by the soldering 53a so that an unusual substance such as flux does not adhere to the cover 51e.
1 is soldered on the side opposite to the light emitting surface. FPC53
A superimposing circuit 52 for reducing the influence of the return light, such as the reflected light from the disk, on the laser of the laser unit 51 is disposed above. Shield case 54 is F
After being fixed by soldering the PC 53 and the laser unit 51, the laser unit 51 is positioned, soldered, and fixed to the FPC 53 from the back surface (the side opposite to the emission side) of the laser unit 51. The method of positioning and fixing the shield case 54 will be described with reference to FIG. The superimposing circuit 52 is substantially hermetically sealed by the shield case 54 and the laser unit 51 so that unnecessary high-frequency radiation generated by the superimposing circuit 52 does not leak outside. Thus, the shield case 54, the FPC5
In the laser unit 51 integrated with the third unit and the like, the pressing unit 56 presses the back surface of the shield case 54 so that the laser unit 51 is fitted to the metal optical base 55.

The laser unit 51 has a laser 5
1a, heat is generated by current flowing from the light receiving element 51b. Since the periphery is packaged with the resin 51d, heat is easily trapped inside. The emission side is fitted with a metal optical bench 55, but this portion is located farther from the laser 51a, the light receiving element 51b, and the terminal 51f of the heat source, and because of the resin portion, heat radiation is not sufficient,
It is necessary to dissipate heat near this heat source. The periphery of the heat source on the back side is sealed by the shield case 54 and the laser unit 51. In order to radiate this heat, the inside of the shield case 54 is filled with heat radiation grease 57. Thus, the heat generated by the laser emission is transmitted from the heat radiation grease 57 to the shield case 54 and is radiated to the outside.

In FIG. 6, a terminal 51f of a laser unit 51 is soldered 53a to an FPC 53,
3 fixed on. When the laser unit 51 is fixed, the shield case 54 is provided with two claw-shaped portions 54h and 54i provided on the left and right sides of the FPC 53 from the rear surface (the side opposite to the emitted light) of the laser unit 51. It is positioned by inserting it into 53h and 53i, and is fixed by soldering 53b around the positioning portion on the same surface as soldering 53a with laser unit 51. The terminal 51f of the laser unit 51 and the soldering 53a of the FPC 53 are
On the other hand, the direction is opposite to the light emitting surface of the laser unit 51, that is, the same direction as the soldering for fixing to the shield case 54 of the FPC 53. The fitting between the laser unit 51 and the optical table 55 is performed by the pressing spring 56 pressing the back surface of the shield case 54. In such a structure, the pressing of the pressing spring 56 is transmitted to the FPC 53 through the shield case 54. Can be Through the FPC 53, a force is applied to the laser unit 51 from the terminal 51 f, which is an electrical connection of the FPC 53, to fit the laser unit 51 to the optical table 55 in a direction in which the electrical connection is peeled off.

[0008]

However, in the above-described optical pickup, a force is exerted in a direction in which the electrical connection of the terminal unit 51f of the laser unit 51 and the FPC 53 by soldering 53a is peeled off by the pressing of the pressing spring 56. As it is added, it stabilizes the quality. Further, the laser 5 in the laser unit 51 having the laser 51a which is easily broken by the temperature rise.
In order to radiate the heat generated by the light-receiving element 1a and the light-receiving element 51b to the outside, a heat-radiating grease 57
, Which required a lot of work time and separate components.

The present invention has been made in view of such conventional problems,
It is an object of the present invention to provide an optical pickup that can enhance the heat radiation effect of a laser unit without increasing the number of parts and working time.

[0010]

SUMMARY OF THE INVENTION In order to solve this problem, an optical pickup according to the present invention is provided with a shield case for preventing unnecessary radiation of a superimposing circuit for reducing noise due to laser return light from a disk. A convex shape is provided on the inside, and the heat generated from the inside of the laser unit by direct contact with the laser unit is conducted from the shield case to the holding spring and the optical bench, and is radiated, so that the number of parts is reduced. The heat radiation effect of the laser unit can be enhanced without increasing the working time.

Also, the terminal portion of the laser unit and the FPC
The electrical connection of the FPC is made on the side opposite to the emission side of the laser unit in the FPC, and the shield case pressed by the holding spring is provided with a convex portion on the inside, and this convex portion is on the side opposite to the emission side of the laser unit. The laser unit is fitted to the optical bench by pressing. This prevents contamination of the emission surface of the laser unit during soldering of the terminal of the laser unit and the FPC,
The laser unit can be fitted to the optical bench by appropriate pressing without applying a load to the terminal portion of the laser unit and the soldering portion of the FPC.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention provides a laser unit having a laser as a light source,
A superimposition circuit for reducing the influence of the return light from the disk to the laser, a shield case for blocking unnecessary radiation from the superimposition circuit, and an optical table on which the laser unit is fixed and optical components are arranged. The shield case is provided with a convex shape on the inside, and is configured to radiate heat generated from the laser unit by contacting the laser unit, so that the heat radiation effect of the laser unit is increased without increasing the number of parts. It has the effect of being able to increase.

According to a second aspect of the present invention, there is provided a laser unit having a laser as a light source, a superimposing circuit for reducing the influence of return light to the laser, and an unnecessary radiation from the superimposing circuit. Pressing a shield case for blocking, an FPC for making an electrical connection to a terminal portion of the laser unit by soldering or the like, an optical table for fixing the laser unit and arranging optical components, and pressing the shield case. A pressing spring for pressing the laser unit against the optical bench, and a terminal portion of the laser unit is electrically connected to the FPC on a side of the FPC opposite to an emission side of the laser unit, and is pressed by the pressing spring. The shield case is provided with a convex portion on the inner side, and the convex portion of the laser unit The morphism side is in the laser unit by pressing the reverse side which is configured to fit to the optical bench, the terminal portion of the laser unit and FPC
That prevents the laser unit's emission surface from being contaminated during soldering, and that the laser unit can be fitted to the optical table by appropriate pressing without applying a load to the terminal part of the laser unit and the soldering part of the FPC. Has an action.

According to a third aspect of the present invention, the projection provided on the shield case is formed by coining so that the shield case substantially seals off unnecessary radiation generated by the superimposed circuit. Therefore, the above-described operation can be achieved without reducing the shielding effect of the shield case.

In the invention according to a fourth aspect of the present invention, the shield case has a U-shaped cross section and the laser unit side is open, and the laser unit has the FPC electrically connected and fixed. In this state, the laser unit can be mounted from the back side of the laser unit, and can be easily mounted from the back side of the laser unit after the laser unit and the FPC are electrically connected by soldering.

According to a fifth aspect of the present invention, the shield case has a claw-shaped portion, and the claw-shaped portion is provided with the F-shaped portion.
It is configured to be positioned by being inserted into a hole provided in the PC. The shield case attached from the back of the laser unit has a claw-shaped part
Positioning can be easily performed by inserting into the hole C.

According to a sixth aspect of the present invention, the projection provided on the shield case has a spring property, and the laser unit is fitted to the optical bench with the spring property. This has an effect of preventing the back surface of the laser unit from being pressed by an excessive load by the spring property.

According to a seventh aspect of the present invention, a ground plane is exposed on the back surface of the laser unit, and the projection of the shield yoke is configured to contact the ground plane. Since the ground plane drawn from the inside of the laser unit comes into contact with the projection of the shield yoke, the heat radiation effect can be remarkably improved, the capacity of the ground plane can be enhanced, and the shield effect can be improved.

According to an eighth aspect of the present invention, at least one of the projections provided on the shield case is arranged at an upper and lower position with respect to the center of the laser unit. An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. FIG. 1 is a side cross-sectional view near a laser unit in an optical pickup according to a first embodiment of the present invention.
2 is a cross-sectional view taken along the line YY of FIG. 1, FIGS. 3A and 3B are front and rear views of a laser unit, and FIG. 4 is a plan view of an FPC where a laser unit is disposed. It is.

In FIG. 1, reference numeral 1 denotes a laser unit having a laser 1a for emitting laser light and a light receiving element 1p for converting return light into an electric signal (see FIG. 3B). The surroundings are made of resin 1j
Packaged in. A cover 1c protects the laser 1a and the light receiving element 1p. The laser unit 1 is connected to the FPC 3 by soldering a metal terminal 1 b to the FPC 3, and is disposed on the FPC 3. The FPC 3 is located on the side opposite to the light emitting surface of the laser unit 1 so that impurities such as flux do not adhere to the cover 1c on the light emitting surface side of the laser unit 1 by the soldering 3a. On the FPC 3, a superimposing circuit 2 for reducing the influence of the laser beam of the laser unit 1 due to the return light is disposed.

Reference numeral 4 denotes a shield case formed in a U-shape in cross section. The shield case 4 has an open side on which the laser unit 1 is mounted. The shield case 4 prevents unnecessary radiation of high frequency generated by the superimposing circuit 2 from leaking outside. The circuit 2 is sealed by a shield case 4. The shield case 4
After fixing the FPC 3 and the laser unit 1 by soldering 3a, the back surface of the laser unit 1 (the side opposite to the emission side)
Projections 4a, 4 provided on the shield case 4 from the
The b and 4c are pressed to a position where they press against the grounding surface 1g exposed on the back surface of the laser unit 1, and are positioned, soldered and fixed to the FPC 3. Shield case 4
The positioning and fixing method will be described with reference to FIG. Thus, in the laser unit 1 integrated with the shield case 4, the FPC 3 and the like, the pressing unit 6 presses the back surface of the shield case 4 so that the laser unit 1 is fitted to the metal optical base 5.

The laser unit 1 has a laser 1
a) Heat is generated by the current flowing from the light receiving element 1p. Since the periphery is packaged with the resin 1j, the structure is such that heat is easily trapped inside. The emission side is fitted with a metal optical table 5, but this part is located farther from the laser 1a, the light receiving element 1p, and the terminal 1b as the heat source.
Because of the resin portion, heat radiation is not sufficient, and it is necessary to radiate heat near this heat source. Further, the periphery of the heat source on the back side is sealed by the shield case 4, but the grounding surface 1 g of the laser unit 1 is exposed to the back side, and the protrusions 4 a, 4 b, 4 c provided on the shield case 4 are directly connected. By directly applying pressure to the ground surface 1g on the back side of the laser unit 1, heat is radiated to the outside of the presser spring 6 and the optical bench 5, and the shielding effect is greatly improved because the ground surface is connected along the same path. be able to.

The projections 4a, 4a,
4b and 4c are formed by coining and do not reduce the shielding effect. In addition, this projection is 3
Because of the individual configuration, the back surface of the laser unit 1 can be pressed with good balance.

In FIG. 2 showing a cross section, the terminal 1b of the laser unit 1 is soldered 3a to the FPC 3,
It is fixed on FPC3. With the laser unit 1 fixed, a shield case 4 attached from the back side (the side opposite to the emitted light) of the laser unit 1
Claw-shaped portions 4h and 4i are provided at three places (see FIG. 3).
Until the convex portions 4a, 4b, 4c of the shield case 4 are pressed against the grounding surface 1g provided on the laser unit 1,
Positioning is performed by inserting the two right and left claw-shaped portions 4h and 4i into the holes 3h and 3i provided in the FPC 3, and the periphery of the positioning portion is soldered on the same surface as the soldering 3a with the laser unit 1. Fix by attaching 3b. The laser unit 1 is fitted to the optical table 5 by the projections 4 a, 4 b, 4 c of the shield case 4 pressed by the pressing spring 6 against the ground surface 1 g on the back surface of the laser unit 1.

The laser unit 1 and the superimposing circuit 2 are attached to an FPC 3 as shown in FIG.
In addition, a necessary circuit is configured by the wiring on the FPC 3.

In such a structure, the laser unit 1
By providing the soldered surface 3a of the FPC 3 on the side opposite to the emission surface of the laser unit 1, it is possible to prevent impurities such as flux from adhering to the cover 1c on the emission surface side by soldering, and to hold down the holding spring. 6 without applying stress in the peeling direction to this soldered part.
It can be transmitted that the laser unit 1 is fitted to the optical bench 5.

[0027]

As described above, according to the present invention, since the soldering surfaces of the laser unit and the FPC are provided on the side opposite to the emission surface of the laser unit, flux or the like is applied to the cover on the emission surface by soldering. While preventing the attachment of impurities, the laser unit can transmit the pressure from the presser spring so that the laser unit fits with the optical bench without applying stress in the peeling direction to this soldered part, so that signal deterioration is reduced. It is possible to provide a highly reliable optical pickup that prevents such a situation and does not apply a load to a portion where a shape change is likely to occur due to an environmental change such as a high temperature such as a soldering portion.

Further, when the convex portion provided on the shield case directly presses against the ground surface provided on the back surface (the side opposite to the emission side) of the laser unit, the heat generated by the laser unit is suppressed by the shield case. Communicate with the spring and the optical bench, and without increasing the number of parts,
It is possible to enhance the heat radiation effect, prevent the laser from being broken easily due to the temperature rise, and provide a high quality optical pickup.

Further, since the grounding surface of the laser unit and the projection of the shield case are in direct contact, the grounding capacity is strengthened, and the shielding effect can be greatly improved.

Further, since the convex portion has a spring property, it is possible to prevent an excessive load from being applied to the laser unit and to have a stable performance against environmental changes such as a temperature environment.

Further, the convex portion of the shield case is formed by coining, so that the above effects can be obtained without reducing the shield effect. Since at least one protrusion is provided at each of the upper and lower portions, the back surface of the laser unit can be pressed in a well-balanced manner.

This shield case has a U-shaped cross section. After the laser unit and the FPC are fixed by soldering, the claw-shaped portion is inserted into the positioning portion of the FPC from the rear side to easily perform positioning. Work time can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a side sectional view near a laser unit in an optical pickup according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line YY of FIG.

FIG. 3A is a front view of the laser unit, and FIG.

FIG. 4 is an FPC in a portion where the laser unit is arranged.
Top view of

FIG. 5 is a side cross-sectional view near a laser unit in a conventional optical pickup.

FIG. 6 is a sectional view taken along line XX of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laser unit 2 Superimposition circuit 3 FPC 3h, 3i hole 4 Shield case 4a, 4b, 4c Convex part 4h, 4i Claw shape part 5 Optical table 6 Press spring

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takayuki Kojima 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Terms (reference) 5D119 AA03 AA38 FA05 FA31 FA36 5F073 AB13 BA05 EA29 FA02 FA29 FA30

Claims (8)

[Claims] 1. A laser unit having a laser as a light source, a superimposing circuit for reducing the influence of return light from the disk to the laser, and a shield case for blocking unnecessary radiation from the superimposing circuit. An optical table for fixing the laser unit and arranging optical components is provided, and the shield case is provided with a convex shape on the inside, and is configured to radiate heat generated from the laser unit by contacting the laser unit. An optical pickup characterized by the following. 2. A laser unit having a laser as a light source, a superimposing circuit for reducing the influence of return light to the laser, a shield case for blocking unnecessary radiation from the superimposing circuit, and the laser. FP for electrical connection with the terminal of the unit by soldering etc.
C, an optical table on which the laser unit is fixed and an optical component is arranged, and a pressing spring for pressing the laser unit against the optical table by pressing the shield case, wherein a terminal portion of the laser unit is the FPC. The FPC is electrically connected on the side opposite to the emission side of the laser unit in the above, and the shield case pressed by the holding spring is provided with a convex portion on the inside, and the convex portion is connected to the emission side of the laser unit. An optical pickup characterized in that the laser unit is fitted to the optical bench by pressing the opposite side. 3. The projection provided on the shield case is formed by coining, and the shield case is configured to substantially seal unnecessary radiation generated by the superimposed circuit. The optical pickup according to claim 2. 4. The shield case has a U-shaped cross section and the laser unit side is open. The laser unit is electrically connected to the FPC and can be attached from the back of the laser unit in a fixed state. The optical pickup according to any one of claims 1 to 3, wherein the optical pickup is configured as follows. 5. The shield case has a claw-shaped portion,
The optical pickup according to claim 4, wherein the claw-shaped portion is positioned by being inserted into a hole provided in the FPC. 6. The laser device according to claim 1, wherein the projection provided on the shield case has a spring property, and the laser unit is fitted to the optical bench with the spring property. 5. The optical pickup according to any one of 5. 7. A ground plane is exposed on a back surface of the laser unit, and a projection of the shield yoke is configured to be in contact with the ground plane.
An optical pickup according to claim 1. 8. The laser apparatus according to claim 1, wherein the projections provided on the shield case are arranged at least one at a time in the upper and lower directions with respect to the center of the laser unit. An optical pickup according to Crab.