JP2003331449A - Optical pickup - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup in which the heat radiation effect of a laser unit is enhanced without spoiling the stability of quality of the optical pickup. <P>SOLUTION: The heat generated from the laser unit in which a light source which emits a laser beam, a photodetector which receives returned light and a hologram element are integrated is conducted to a heat radiation cover and further a case and radiated by using a member which has an excellent heat conductivity. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for recording / reproducing signals on / from an optical disc such as a CD or a DVD.

[0002]

2. Description of the Related Art An optical pickup device is an information recording / reproducing device characterized by non-contact, large capacity, high speed access and low cost media. By utilizing these features, a recording / reproducing device for digital audio signals and digital video signals. Or as an external storage device of a computer.

In all of the optical pickups mounted on such optical pickup devices, laser light emitted from a laser light source is focused on a disk by an objective lens, and light corresponding to a signal on the disk is received by a light receiving element. Then, it is converted into an electric signal and transmitted to an external electric circuit.

An example of the vicinity of a conventional laser unit will be described below with reference to the drawings. 4 is a perspective view of the vicinity of a laser unit in a conventional optical pickup, FIG. 5 is a plan sectional view, and FIG. 6 is a sectional view taken along line BB of FIG.

In FIG. 6, reference numeral 3 denotes a laser unit, which has a laser for emitting a laser beam and a light receiving element for converting return light into an electric signal, has a ground plane 5 at the rear portion, and is surrounded by a resin package. . The laser unit 3 is held on a metal plate 4 by adhesion, and the plate 4 is positioned and fixed to the case 1 by adhesives 6a and 6b. The laser unit 3 is electrically connected to the flexible printed circuit board (hereinafter referred to as FPC) 2 by soldering.

Further, the laser unit 3 generates heat by the light emission of the laser and the current flowing through the light receiving element. Since the surrounding area is packaged with resin, the structure is such that heat can easily be stored inside. Therefore, in order to use this laser unit 3 stably and efficiently, it is necessary to efficiently radiate the heat generated from the laser unit 3 to the outside. The heat generated by the light emission of the laser and the current flowing through the light receiving element is radiated from the ground plane 5 at the rear part.

A metal cover 61 for preventing dust and radiating heat is attached to the case 1 on which the laser unit 3, the FPC 2 and other optical parts are mounted.

The metal cover 61 has a cantilevered portion 61.
a, and has a spring property. The diaphragm portion 61a having this spring property is attached to the case 1 so as to be pressed against the grounding surface 5 at the rear portion of the laser unit 3 with a certain degree of bending. Further, the metal cover 61 is in surface contact with the case 1 so that the heat transferred from the laser unit 3 can be transferred to the case 1.

[0009]

However, in the above optical pickup, the elastic diaphragm portion 61a of the metal cover 61 constantly applies an external force to the laser unit 3, which stabilizes the quality. It was the one that hindered the transformation. Further, the metal cover 61 needs a material having a spring property, and since these materials generally have low thermal conductivity, there is a drawback that efficient heat dissipation characteristics cannot be obtained.

The present invention has been made in view of such conventional problems.
An object of the present invention is to provide an optical pickup having high reliability and capable of enhancing the heat radiation effect of the laser unit.

[0011]

In order to solve this problem, the pickup of the present invention uses a heat generated from a laser unit in which a light source for emitting a laser beam, a light receiving element for receiving return light and a hologram element are integrated. Is configured to enhance the heat dissipation performance by conducting to the heat dissipation cover and further to the case by interposing a metal block with good heat conductivity, which ensures high reliability and heat dissipation of the laser unit. The efficiency can be improved.

Further, the metal block having good heat conductivity is configured to be slidable with respect to the heat radiation cover. As a result, even if the position of the laser unit varies a little, the tip surface of the metal block can be surely brought into contact with the grounding surface, so that heat can be transferred efficiently and no external force is applied to the laser unit. Can be stabilized.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is characterized in that heat generated from a laser unit in which a light source for emitting a laser beam, a light receiving element for receiving return light and a hologram element are integrated is By interposing a metal block with good conductivity, it is configured to conduct heat from the metal block to the heat dissipation cover, and further to the case, so that the heat dissipation is high and the heat dissipation effect of the laser unit is high. It has the effect that it can be increased.

According to a second aspect of the present invention, heat generated from a laser unit in which a light source for emitting a laser beam, a light receiving element for receiving return light and a hologram element are integrated has good thermal conductivity. By interposing a metal block, it is configured to conduct and dissipate heat to the heat dissipation cover and further to the case, and the engaging part of the metal heat dissipation cover with the metal block is formed into a cylindrical shape by burring. Also, by making the shape of the metal block cylindrical so that the metal block is slidable with respect to the metal heat dissipation cover, even if the laser unit position varies a little, the ground plane of the laser unit The tip surface of the metal block can be securely brought into contact with the metal block, so that heat can be transferred efficiently, and an external force is applied to the laser unit. Since no addition, an effect that it is possible to stabilize the quality.

An embodiment of the present invention will be described below with reference to FIGS. 1 is a side sectional view (a cross section taken along the line AA in FIG. 3) of a laser unit of an optical pickup according to an embodiment of the present invention, FIG. 2 is a perspective view of the vicinity of the laser unit, and FIG. Is.

In FIG. 1, reference numeral 3 denotes a laser unit, which has a laser for emitting a laser beam and a light receiving element for converting return light into an electric signal, has a ground plane 5 at the rear portion, and is surrounded by a resin package. . The laser unit 3 is held on a metal plate 4 by adhesion, and the plate 4 is positioned and fixed to the case 1 by adhesives 6a and 6b. The laser unit 3 is electrically connected to the flexible printed circuit board (hereinafter referred to as FPC) 2 by soldering.

Further, the laser unit 3 generates heat by the light emission of the laser and the current flowing through the light receiving element. Since the surrounding area is packaged with resin, the structure is such that heat can easily be stored inside. Therefore, in order to use this laser unit 3 stably and efficiently, it is necessary to efficiently radiate the heat generated from the laser unit 3 to the outside. Further, the heat generated by the light emission of the laser and the current flowing in the light receiving element is radiated from the ground plane 5 at the rear part.

The case 1 on which the laser unit 3, the FPC 2 and other optical parts are mounted has a metal cover 11 attached thereto for preventing dust and radiating heat.

The metal cover 11 has a burring portion 11a narrowed down into a cylindrical shape. In addition, the cylindrical metal block 12 made of a material having good thermal conductivity is engaged with the burring portion 11a of the metal cover 11 with a minimum clearance so that it can slide in the P direction. I am configuring.

Here, in order to dissipate the heat generated from the laser unit 3 from the rear ground plane 5, the tip 12a of the metal block 12 is in contact with the ground plane 5.
The reason why the metal block 12 is configured to be slidable with respect to the metal cover 11 is to absorb the positional variation of the laser unit 3. With such a configuration, the metal block 12 can be removed from the ground plane 5. Metal block 1
The heat can be surely transferred to 2.

The heat of the metal block 12 is transferred to the metal cover 11 by the engaged burring portion 11a, so that the heat radiation effect can be further enhanced. At this time, in order to further improve the heat transfer effect and to fix the metal block 12, the gap 13 between the ground plane 5 and the metal block tip 12a and the gap between the metal block 12 and the metal cover 11 are formed. It goes without saying that it is more efficient to fill 14 with the heat dissipation grease 15.

The metal cover 11 has a structure to be attached to the case 1. As shown in FIG. 2, in the case of the present embodiment, it is a patching method using unevenness. Therefore,
It can be seen that the heat conducted from the laser unit 3 → the metal block 12 → the metal cover 11 is further conducted to the case 1, so that the heat can be dissipated very efficiently.

Further, unlike the conventional example, a constant external force is not continuously applied to the rear ground contact surface 5 of the laser unit 3, so that the quality stability can be further improved.

[0024]

As described above, according to the present invention, the heat generated from the laser unit in which the light source that emits the laser beam, the light receiving element that receives the return light, and the hologram element are integrated with each other has a thermal conductivity. It is configured to conduct heat to the heat dissipation cover and further to the case through a good member to dissipate the heat, and thus, the reliability is high and the heat dissipation effect of the laser unit can be enhanced.

Further, since the metal block is constructed so as to be slidable with respect to the heat dissipation cover, even if the position of the laser unit varies a little, the tip surface of the metal block can be surely brought into contact with the ground plane of the laser unit. Therefore, heat can be efficiently transferred, and no external force is applied to the laser unit, so that a high quality optical pickup can be provided.

[Brief description of drawings]

FIG. 1 is a side sectional view near a laser unit in an optical pickup according to an embodiment of the present invention (A in FIG. 3).
-A sectional view).

FIG. 2 is a perspective view of the vicinity of a laser unit in the optical pickup according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view of a plane near the laser unit in the optical pickup according to the embodiment of the present invention.

FIG. 4 is a perspective view of the vicinity of a laser unit in the optical pickup according to the conventional embodiment.

FIG. 5 is a cross-sectional view of a plane near a laser unit in an optical pickup according to a conventional embodiment.

FIG. 6 is a side sectional view (sectional view taken along the line BB in FIG. 5) near the laser unit in the optical pickup according to the conventional embodiment.

[Explanation of symbols]

1 ... Case, 2 ... FPC, 3 ... Laser unit,
4 ... Plate, 5 ... Ground plane, 6a, 6b ... Adhesive,
11 ... Metal cover, 11a ... Burring part, 12 ...
・ Metal block, 12a ... Metal block tip, 1
3, a gap between the ground plane 5 and the tip 12a of the metal block,
14 ... Gap between metal block 12 and metal cover 11, 15 ... Heat dissipation grease, 61 ... Metal cover, 61
a ... diaphragm part.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shinji Fujita             292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa             Ceremony Hitachi Digital Media Development Book             Department (72) Inventor Masachi Fukui             292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa             Ceremony Hitachi Digital Media Development Book             Department (72) Inventor Ikuo Shinoda             292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa             Ceremony Hitachi Digital Media Development Book             Department F term (reference) 5D119 AA33 AA39 BA01 BB01 BB02                       BB03 FA30 FA32 FA35 MA09                 5D789 AA33 AA39 BA01 BB01 BB02                       BB03 FA30 FA32 FA35 MA09

Claims (2)

[Claims] 1. An optical pickup for irradiating an optical disc with a laser beam to receive return light from the disc, wherein a light source for emitting the laser beam, a light receiving element for receiving the return light, and a hologram element are integrated. A laser unit, a plate for holding the laser unit, a case on which the plate is mounted, and a metal heat dissipation cover, and heat transfer between the laser unit and the metal heat dissipation cover An optical pickup characterized in that it is configured to intervene with a member having good conductivity. 2. A member having good thermal conductivity is formed into a cylindrical metal block, and an engaging portion of the metal heat dissipation cover with the metal block is formed into a cylindrical shape by burring and is engaged. The optical pickup according to claim 1, wherein the metal block is configured to be slidable with respect to the metal heat dissipation cover.