JP3445938B2 - Optical pickup device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup device used for recording and reproducing an optical recording disc such as a CD (compact disc) or a DVD (digital video disc). More specifically, the present invention relates to a heat radiation structure of a light source unit in which a laser light source, a light detection element, and a light guide element such as a hologram element are integrated.

[0002]

2. Description of the Related Art An optical pickup device used for recording and reproducing an optical recording disk such as a CD or a DVD emits a laser diode and a laser diode as disclosed in, for example, Japanese Patent No. 2662054. One using a light source unit in which a photodetector element for receiving the return light of the laser light from the optical recording disk and a hologram element for guiding the return light to the photodetector element are integrated by a single package. is there. By using such a light source unit, the mounting area can be reduced as compared with the case where the laser diode, the photodetecting element and the hologram element are separately mounted on the frame, so that the apparatus can be made smaller and thinner. Further, the number of assembling steps can be reduced and the manufacturing cost can be reduced, so that the cost of the optical pickup device can be reduced.

Here, the package of the light source unit includes
Resin mold packages are often used.

[0004]

However, since the resin mold package has poor heat dissipation, there is a problem that the temperature of the laser diode rises due to the heat generated when the laser diode operates and the life of the laser diode is shortened. is there. A method of embedding a heat dissipation plate such as a metal plate in a resin mold package can be considered to prevent such an adverse effect. However, with such a configuration, the light source unit becomes large, so that the optical pickup device cannot be downsized. I can't plan. In addition, since the mold for manufacturing the resin mold package is complicated, the light source unit cannot be manufactured at low cost.

In view of the above problems, the object of the present invention is to
An object of the present invention is to provide an optical pickup device capable of improving heat radiation from a light source unit without hindering downsizing, thinning, and cost reduction.

[0006]

In order to solve the above-mentioned problems, according to the present invention, a laser light source for irradiating an optical recording disk with a laser beam, and a light detection for receiving a return light of the laser beam from the optical recording disk. An optical pickup device having a light source unit in which an element and a light guide element for guiding the return light to the photodetection element are integrated by an insulating package, and a metal frame on which the light source unit is mounted, In the flexible package, a window is formed to partially expose the internal ground wiring, and
A metal heat dissipation member is in contact with the ground wiring through the window. As used herein, the term "contact" means that the members are in direct contact with each other,
This also includes the case where the members are in contact with each other via a conductive material such as solder.

In the present invention, since the internal ground wiring is exposed from the window formed in the insulating package, the heat radiation performance of the light source unit is improved simply by bringing the heat radiation member into contact with the ground wiring through this window. To do. Therefore, since the temperature rise of the laser light source can be suppressed to a low level, the deterioration of the laser light source can be prevented. Further, unlike the method of embedding the heat sink in the package of the light source unit, only the window needs to be formed in the package of the light source unit, so that a complicated mold is not necessary and the miniaturization of the light source unit is not hindered. Therefore, downsizing of the optical pickup device
It is possible to reduce the thickness and the cost.

In the present invention, if the heat dissipation member is in contact with a metal fixing member that presses and fixes the light source unit onto the frame with springiness, the heat of the light source unit passes from the heat dissipation member to the fixing member. Conducts heat to the frame. Therefore, the heat dissipation of the light source unit can be further enhanced.

In the present invention, it is preferable that the heat dissipation member is a metal fixing member that fixes the light source unit to the frame with a spring property. According to this structure, even if the heat radiation member is attached to the light source unit, it is not necessary to add a separate member, so that it is possible to prevent an increase in the number of parts.

In this case, it is preferable that the fixing member is in contact with the frame. According to this structure, the heat of the light source unit is conducted from the fixing member to the frame, so that the heat dissipation of the light source unit can be enhanced.

In the present invention, it is preferable that the heat dissipation member is in contact with the frame. Even in this case, the heat of the light source unit is conducted to the frame via the heat dissipation member, so that the heat dissipation can be improved.

In the present invention, the heat dissipation member may be the frame itself.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an optical pickup device of the present invention will be described below with reference to the drawings.

[First Embodiment] (Overall Configuration) FIG. 1A is a plan view showing an optical pickup device according to a first embodiment of the present invention, and FIG. 1B is a plan view of FIG. It is sectional drawing in the II 'line.

As shown in FIGS. 1A and 1B, the optical pickup device 1 records and reproduces data on an optical recording disk 14 such as a CD or a DVD.
A frame 2 arranged to face the recording surface of 4;
The light source unit 3 attached to the frame 2, an objective lens 44 for condensing the laser light L emitted by the light source unit 3 on the optical recording disk 14, and an objective lens for driving the objective lens 44 in the focusing direction and the tracking direction. And a drive unit 4.

The frame 2 is an aluminum die-cast product extending with a constant thickness. Inside the frame 2, a light source unit housing portion 21 penetrating in the thickness direction for housing the light source unit 3 and an objective lens drive. An objective lens driving device housing portion 22 is formed to penetrate the device 4 in the thickness direction to house the device 4.

Further, two guide holes 23 and a U-shaped projecting guide portion 24 are formed in the outer peripheral portion of the frame 2, and these are picked up by the optical pickup as the optical recording disk 5 is recorded or reproduced. A guide shaft 15 for moving the device 1 in the radial direction of the optical recording disk 5 (direction indicated by arrow A) is passed through. Furthermore, on the upper surface of the frame 2,
In order to protect the objective lens driving device 4, a thin plate-shaped cover 11 covering the upper side thereof is attached.

(Objective Lens Driving Device 4) The objective lens driving device 4 includes a lens holder 43 holding an objective lens 44.
And a support shaft 42 that supports the lens holder 43 so as to be movable in the focusing direction and the tracking direction, and a support member 41 on which the support shaft 42 is erected. The lens holder 43 includes a cylindrical body portion 43, and a lens holding portion 430 that is thinly projected toward the outer peripheral side is formed on the upper surface of the body portion 43. A shaft hole 42 is formed in the center of the body portion 43, and the support shaft 42 is inserted therein. On the other hand, the support member 41 is provided with a rectangular bottom plate 410 on which a support shaft 42 is erected in the center, and side plates 411 that are erected at right angles from the outer peripheral edge of the bottom plate 410.

Between the lens holder 43 and the support member 41, the lens holder 43 is vertically moved along the support shaft 42 in order to correct the focusing error of the light spot focused on the optical recording disk 14 by the objective lens 44. And a focusing magnetic drive circuit (not shown) that moves the lens holder 43 to perform tracking error correction of the light spot focused on the optical recording disk 14 by the objective lens 44.
A tracking magnetic drive circuit (not shown) for rotating the shaft around the spindle 42 is configured.

(Light Source Unit 3) The light source unit 3 has a structure in which a laser diode 31 (laser light source), a photodetection element 32, and a hologram element 33 (light guide element) are integrated. That is, the light source unit 3 includes a resin mold package 34 (insulation package) having a substantially rectangular parallelepiped shape.
The laser diode 31 and the photodetector 32 are arranged inside the package 34. Also,
The front surface 34 from which the laser light L of this package 34 is emitted
A hologram element 33 is attached to 5. Furthermore, from the rear surface 344 of the package 34, a plurality of input / output terminals 36 extending from the laser diode 31 and the photodetector 32 are projected. The flexible printed circuit board 13 is connected to the input / output terminal 36.

The light source unit 3 is attached to the frame 2 so that the laser light L emitted from the laser diode 31 is irradiated toward the objective lens driving device housing hole 22 side. Between the light source unit 3 and the objective lens driving device housing hole 22, the total reflection mirror 12 is arranged so as to face obliquely upward. An objective lens 44 is arranged above the total reflection mirror 12. Therefore, the laser light L emitted from the laser diode 31 passes through the hologram element 33, is raised by the total reflection mirror 12, enters the objective lens 44, and is condensed on the recording surface of the optical recording disk 14. . The return light from the optical recording disk 14 follows the same path again, is diffracted by the hologram element 33, and is applied to the light detection element 32 of the light source unit 3. Therefore, the optical pickup device 1 generates a reproduction signal of the optical recording disk 14, a tracking error signal, and a focusing error signal based on the return light detected by the photodetector 32.

Here, the light source unit 3 is fixed to the frame 2 as described below, and at the same time, the heat dissipation of the light source unit 3 is improved.

First, as shown in FIG. 2, the light source unit 3
The heat dissipation plate 5 (heat dissipation member) is attached to the upper surface 341 of the resin mold package 34. The heat dissipation plate 5 is formed of a metal plate such as copper or aluminum,
A substantially rectangular top plate 51 that is in close contact with the upper surface 341 of the package 34, side plate portions 53 and 54 that extend in an arc shape that bulges outward from both end portions of the top plate 51, and side plate portions 53, 5
4 are provided with rear plate portions 55 and 56 extending inwardly from the rear end of the rectangular plate 4 in a rectangular shape. Further, the top plate 51 is formed with a protruding portion 52 that is extruded downward in a substantially rectangular shape by press working.

On the other hand, a substantially rectangular window 35 is formed on the upper surface 341 of the package 34 of the light source unit 3 at a position corresponding to the protruding portion 52 of the top plate 51 of the heat dissipation plate 5. The ground wiring 37 connected to the laser diode 31 and the photodetector 32 is partially exposed from the window 35.

Therefore, when the heat sink 5 is attached to the light source unit 3, the projecting portion 52 of the heat sink 5 is fitted into the window 35 formed in the package 34 of the light source unit, and the projecting portion 52 and the ground wiring 37 come into contact with each other. In this state, the protruding portion 52 of the heat sink 5 and the ground wiring 37 are soldered.

The side plate portions 53 and 54 of the heat dissipation plate 5 are in close contact with both side surfaces 341 and 342 of the package 34 of the light source unit 3 and hold the package 34 from both sides. further,
The rear plate portions 55 and 56 of the heat sink 5 are the rear surface 3 of the light source unit 3.
Of 44, the input / output terminal 36 is in contact with the lower side of the protruding portion.

In this way, the light source unit 3 to which the heat dissipation plate 5 is attached is arranged inside the light source unit accommodating portion 21 of the frame 2 and the leaf spring 6 as shown in FIGS. (Fixing member) pushes forward and fixes.

The leaf spring 6 used here is formed by forming a metal plate such as copper or aluminum in a U-shaped cross section. One of the pair of bent portions 61, 62 formed in the leaf spring 6 and extending substantially parallel to each other is
It is in close contact with the inner surface 25 of the light source unit housing hole 21. The other bent portion 62 is formed by the rear plate portions 55, 5 of the heat dissipation plate 5.
It adheres to 6. In this state, the leaf spring 6 is sandwiched between the inner surface 25 of the light source unit housing 21 and the light source unit 3 in an elastically deformed state. Therefore, the light source unit 3 is biased forward by the elastic return force. Further, the light source unit housing hole 21 is formed with an inner wall 27 against which the front surface 345 of the light source unit 3 abuts. Therefore,
Since the front surface 345 of the light source unit 3 is pressed against the inner wall 27 by the biasing force of the leaf spring 3, the light source unit 3 is fixed thereto.

In the optical pickup device 1 thus constructed, since the heat sink 5 is in contact with the ground wiring 37 extending from the laser diode 31 of the light source unit 3, it is generated by driving the laser diode 31. The generated heat is conducted to the radiator plate 5 through the ground wiring 37 and is radiated from the radiator plate 5. Further, since the rear plate portions 55 and 56 of the heat dissipation plate 5 are in close contact with the plate spring 6, the heat of the heat dissipation plate 5 is conducted to the plate spring 6 and is also dissipated from the plate spring 6. Further, since the leaf spring 6 is in close contact with the frame 2, the heat of the leaf spring 6 is conducted to the frame 2,
You can also radiate heat from.

(Effect of this Embodiment) As described above, in the optical pickup device 1 of this embodiment, since the internal ground wiring 37 is exposed from the window 35 formed in the resin mold package 34 of the light source unit 3, this window is exposed. Only by bringing the heat dissipation plate 5 into contact with the ground wiring via 35, the heat dissipation property is improved. In addition, the heat sink 5 connects the light source unit 3 to the frame 2
Is in contact with a metal leaf spring 6 for fixing to, and the leaf spring 6 is in contact with the metal frame 2. Therefore,
The heat of the light source unit 3 is conducted to the frame 2 from the heat radiating plate 5 through the plate spring 6, so that the heat radiating property is excellent. Therefore, the temperature rise of the laser diode 31 can be suppressed to a low level, the deterioration of the laser diode 31 can be prevented, and the life of the laser diode 31 can be extended.

Further, in manufacturing the light source unit 3, unlike the method of embedding a heat sink in the package 34 of the light source unit 3, since only the window 35 needs to be formed in the light source unit 3, a complicated mold is not required. Moreover, the miniaturization of the light source unit 3 is not hindered. Therefore, it is possible to reduce the size and thickness of the optical pickup device 1 and to reduce the cost.

[Second Embodiment] FIG. 3A is a plan view of an optical pickup device according to a second embodiment of the present invention.
3B is a sectional view taken along line II-II ′ of FIG. Since the optical pickup device 1A of the present embodiment has the same basic configuration as the optical pickup device 1 described in the first embodiment, parts having common functions are designated by the same reference numerals, and description thereof will be given. Is omitted.

As shown in FIGS. 3A and 3B, in the optical pickup device 1A of this embodiment, the fixing member 5A for fixing the light source unit 3 to the frame 2 is used as the heat radiation member of the light source unit 3.

As shown in FIG. 4, the fixing member 5A is formed of a metal plate such as copper or aluminum, and has a substantially rectangular top plate 5 that is in close contact with the upper surface 341 of the package 34.
1A, front plate portions 57 and 58 extending downward from both ends of the front edge of the top plate 51A, respectively, and the top plate 51A.
A leaf spring portion 64 extending downward from both ends of the rear edge of
Equipped with 65.

The leaf spring portions 64 and 65 are bent downward from upper ends 641 and 651 extending downward from the rear edge of the top plate 51A, and from the tips of the central portions inward from the lower ends of the upper portions 641 and 651. Lower parts 642 and 652.

At the position corresponding to the window 35 formed in the package 34 of the light source unit 3 on the top plate 51A, a rectangularly cut out portion with one side left is bent obliquely downward and protruded. 52A is formed. A tip portion 521 of the protruding portion 52A is bent in parallel with the top plate 51A.

When the fixing member 5A thus formed is attached to the light source unit 3, the tip portion 521 of the projecting portion 52A of the heat sink 5 is fitted into the window 35 formed in the package 34 of the light source unit, and the projecting portion 52A. The front end portion 521 of the above contacts the ground wiring 37. In this state, the fixing member 5A
The projecting portion 52A and the ground wiring 37 are soldered.

The front plate portions 57 and 58 of the fixing member 5A are also provided.
On the front surface 345 of the package 34 of the light source unit 3 on both sides of the hologram element 33 attachment portion.
Furthermore, the lower portion 64 of the leaf spring portions 64, 65 of the fixing member 5A
The reference numerals 2, 652 make close contact with the rear surface 344 of the light source unit 3 below the portion where the input / output terminals 36 project.
The fixing member 5A includes the front plate portions 57 and 58 and the plate spring portion 6.
The package 34 of the light source unit 3 is held by being sandwiched by the front and rear portions by 4, 65.

Next, as shown in FIG. 3B, the light source unit 3 to which the fixing member 5A is attached is fitted inside the light source unit housing portion 21 formed in the frame 2. By doing so, the upper portions 641 and 651 of the leaf spring portions 64 and 65 formed on the fixing member 5A come into close contact with the inner surface 26 of the light source unit housing hole 21. As a result, the leaf spring portions 64 and 65 are sandwiched between the inner surface 26 of the light source unit 21 and the light source unit 3 in an elastically deformed state. Therefore,
Since the light source unit 3 is biased forward by the elastic return force, the front surface 345 of the light source unit 3 is pressed against the inner wall 27 formed in the light source unit housing hole 21.
Therefore, the light source unit 3 is fixed to the frame 2.

In the optical pickup device 1 thus constructed, the fixing member 5A is in contact with the ground wiring 37 extending from the laser diode 31, so that the heat generated by driving the laser diode 31 is grounded. It conducts to the fixing member 5A through the wiring 37 and is radiated by the fixing member 5A. Further, since the fixing member 5A is in contact with the frame 2, the heat of the fixing member 5A can be released to the frame 2 and can also be radiated from the frame 2.

As described above, in the optical pickup device 1 of this embodiment, the fixing member 5A is connected to the ground wiring 37 exposed from the window 35 formed in the package 34 of the light source unit 3, so that the light source unit is connected. The heat dissipation of No. 3 is improved. Further, since the fixing member 5A is in contact with the frame 2, the heat dissipation is even higher. Therefore, since the temperature rise of the laser diode 31 can be suppressed to a low level, the deterioration of the laser diode 31 can be prevented.

Further, since the fixing member 5A is used as the heat radiating member of the light source unit 3, even if the heat radiating member is attached to the light source unit 3, it is not necessary to add another member. Therefore, it is possible to prevent the number of parts from increasing.

[Other Embodiments] As shown in FIG. 5, there is provided a projecting portion 52B which comes into contact with the internal ground wiring 37 through the window 35 formed in the upper surface 341 of the package 34 of the light source unit 3. A metal plate composed of the top plate 51B may be used as the heat dissipation plate 5B (heat dissipation member). In this case, the top plate 51B is attached to the package 34 of the light source unit 3.
The upper surface 341 may be attached to the upper surface 341 by a method such as adhesion. Here, the heat radiation plate 5B is connected to the ground wiring 37 of the light source unit 3.
If the heat sink 5B contacts the frame 2 (see FIG. 1)
Although the heat capacity increases, the heat dissipation of the light source unit 3 can be improved even if the heat sink 5B is not in contact with the frame 2. However, if the heat sink 5B is in contact with the frame 2, the heat of the heat sink 5B is released to the frame 2. As a result, the heat dissipation of the light source unit 3 can be further improved.

Further, the frame 2 may be brought into direct contact with the ground wiring 37 exposed from the window 35 of the light source unit 3.

Further, the heat dissipation plate 5, 5B or the fixing member 5
If a material having good thermal conductivity, such as silicon grease, is interposed between the protruding portions 52, 52A, 52B formed on A and the ground wiring 37, heat dissipation can be further improved.

[0046]

As described above, in the optical pickup device of the present invention, since the internal ground wiring is exposed from the window formed in the insulating package of the light source unit, the heat radiation member is grounded through this window. The heat dissipation of the light source unit can be improved simply by bringing it into contact with the wiring.
Therefore, since the temperature rise of the laser light source can be suppressed to a low level, the deterioration of the laser light source can be prevented. Further, unlike the method of embedding the heat sink in the package of the light source unit, only the window needs to be formed in the package of the light source unit, so that a complicated mold is not necessary and the miniaturization of the light source unit is not hindered. Therefore, it is possible to reduce the size and thickness of the optical pickup device and reduce the cost.

[Brief description of drawings]

1A is a plan view showing an optical pickup device according to a first embodiment of the present invention, and FIG. 1B is a line I- of FIG.
It is sectional drawing in the I'line.

FIG. 2 is a perspective view showing a heat radiating plate and a leaf spring attached to a light source unit of the apparatus shown in FIG.

3A is a plan view showing an optical pickup device according to a second embodiment of the present invention, and FIG. 3B is a II-I of FIG.
It is a sectional view taken along the line I '.

FIG. 4 is a perspective view showing a fixing member attached to a light source unit of the apparatus shown in FIG.

FIG. 5 is a perspective view showing a heat dissipation plate attached to a light source unit according to another embodiment of the present invention.

[Explanation of symbols]

1, 1A optical pickup device 2 frames 3 light source unit 4 Objective lens drive 5, 5B Heat dissipation plate (heat dissipation member) 5A fixing member (heat dissipation member) 6 Leaf spring (fixing member) 31 Laser diode 32 Photodetector 33 Hologram element (light guide element) 34 Resin mold package (insulation package) 35 windows 37 Ground wiring

Claims (6)

(57) [Claims] 1. A laser light source for irradiating an optical recording disk with laser light, a photodetector element for receiving return light of the laser light from the optical recording disk, and a light guide element for guiding the return light to the photodetector element. In an optical pickup device having a light source unit integrated by an insulating package and a metal frame on which the light source unit is mounted, the insulating package has a window for partially exposing the internal ground wiring. And a metal heat dissipation member is in contact with the ground wiring via the window. 2. The optical pickup device according to claim 1, wherein the heat radiating member is in contact with a metal fixing member that presses and fixes the light source unit against the frame with a spring property. 3. The optical pickup device according to claim 1, wherein the heat dissipation member is a metal fixing member that fixes the light source unit to the frame with a spring property. 4. The optical pickup device according to claim 2, wherein the fixing member is in contact with the frame. 5. The optical pickup device according to claim 1, wherein the heat dissipation member is in contact with the frame. 6. The optical pickup device according to claim 1, wherein the heat dissipation member is the frame itself.