JP2005203019A - Optical pickup device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup device for efficiently cooling a driver IC that generates heat in operation. <P>SOLUTION: The optical pickup device 1 irradiates an optical disk 100 with a laser beam 47a, and receives reflection light 47b reflected by the optical disk 100. The optical pickup device 1 comprises a light-emitting element 411 for emitting the laser beam 47a, a light receiving element 412 for receiving the reflection light 47b in which the laser beam 47a are reflected by the optical disk 100, a driver IC 51 for driving the light-emitting element 411, and a base 3 made of a metal material. The driver IC 51 is provided on the base 3 so that the bottom surface 511 comes into contact with the base 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical pickup device.

  Usually, a driver IC included in an optical pickup device is installed on a base (substrate) in the device. The driver IC is covered with a shield case that blocks electromagnetic waves from the outside. However, in such a configuration, when the driver IC generates heat in the operating optical pickup device, there is a problem in that the temperature in the shield case rises and hinders driving of the driver IC.

  With regard to such a problem, a technique described in Patent Document 1 is disclosed in a conventional optical pickup device. In this optical pickup device, a heat conductive member is installed on the upper surface (top surface) of the driver IC, and the driver IC and the shield case are brought into contact with each other so as to be able to transfer heat. As a result, when the driver IC generates heat when the optical pickup device is in operation, the heat is transmitted to the shield case via the heat conductive member, and is released from the shield case to the outside air. Can be cooled.

  However, in the optical pickup device as described above, there is a problem that the heat dissipation efficiency for the heat generated from the driver IC is low and the driver IC is not sufficiently cooled.

JP-A-11-185273

  An object of the present invention is to provide an optical pickup device that can efficiently dissipate heat generated from a driver IC.

Such an object is achieved by the present inventions (1) to (4) below.
(1) On the case,
A light emitting element that emits laser light;
A light receiving element that receives the reflected light of the laser beam reflected by the optical disc;
An optical element provided between optical paths from the light emitting element to the light receiving element;
An optical pickup device comprising a laser driver for driving the light emitting element,
The optical pickup device, wherein the light emitting element, the optical element, and the laser driver are fixed on a base made of a metal material and further mounted on the casing.

(2) A circuit board provided with a through hole at a position corresponding to the laser driver,
The bottom surface of the laser driver is fixed in direct contact with the base through the through hole,
The optical pickup device according to (1), wherein the circuit board is fixed to the base surface so as to surround the laser driver and connected to the laser driver.

(3) The optical element is
A coupling lens for condensing the laser beam;
A grating that diffracts the focused laser beam;
A dichroic prism that reflects or transmits the diffracted laser light and the reflected light;
A collimator lens that collimates the diffracted laser light and the reflected light, and
The optical pickup device according to (1) or (2), further including a sensor lens that condenses the reflected light on the light receiving element.

(4) The base and the light receiving element are fixed to a module mounting portion of the housing,
The optical pickup device according to any one of (1) to (3), wherein the module mounting portion is formed by forming the casing in a substantially frame shape, and the inside of the casing is hollow.

  According to the optical pickup device of the present invention, the driver IC is installed so as to come into contact with the base made of a metal material. Therefore, when the optical pickup device is in operation, this heat is generated when the driver IC generates heat. It is transmitted directly from the driver IC to the base and released into the air. Thereby, the heat generated from the driver IC can be efficiently radiated.

  The optical pickup device of the present invention will be described below in detail based on preferred embodiments shown in the accompanying drawings.

  FIG. 1 is a perspective view showing an outline of the optical pickup device of the present invention, and FIGS. 2 and 3 are a plan view and a side view showing the vicinity of a driver IC installed in the optical pickup device shown in FIG. 1, respectively.

  The optical pickup device 1 irradiates the optical disc 100 with the laser beam 47a and receives the laser beam 47a reflected by the optical disc 100. As shown in FIG. 1, the optical pickup device 1 has a housing 2, a base 3, and an optical system. 4 and a drive circuit 5.

  The optical pickup device 1 is applied to, for example, an optical disc drive mounted on a computer (personal computer), video equipment, audio equipment, or other electronic equipment, and in particular, an optical disc drive capable of reading a plurality of types of optical discs 100. The

  Examples of the optical disc 100 include a CD (compact disc) and a DVD (digital video disk).

Hereinafter, the configuration of each unit will be described.
A housing 2 shown in FIG. 1 accommodates a lens holder that holds an objective lens (not shown) and a lens actuator that includes a damper base that supports the lens holder with a suspension wire, above the reflecting mirror 45, and includes a base 3 and an optical system 4. The drive circuit 5 is accommodated in the module mounting portion 21. When the optical pickup device 1 is in operation, the optical pickup device 1 is supported by a drive mechanism (not shown) of an optical disk drive via a drive shaft 23 that movably supports the housing 2. Driven by the drive mechanism, the position relative to the optical disc 100 is displaced.

  As shown in FIG. 1, the base 3 has a substantially plate shape, and is fixed to the module mounting portion 21 of the housing 2 using screws (screws) 31. The base 3 is made of a metal material, and is provided with a circuit board 52a connected to a lead wire (terminal) 53 of a driver IC 51 described later. The module mounting portion 21 has a space that can accommodate the base 3 and the photodiode 46 by forming the casing 2 in a substantially frame shape and hollowing the inside thereof.

  In addition, although it does not specifically limit as a metal material, For example, various metals, such as iron, nickel, stainless steel, copper, brass, aluminum, titanium, or an alloy containing these are used.

  As shown in FIG. 1, the optical system 4 includes a first light emitting element 411, a second light emitting element 412, a coupling lens 48, a grating 49, a dichroic prism 43, a collimator lens 44, a reflecting mirror 45, and the like. , A sensor lens 42, and a photodiode (light receiving element) 46.

  The first light emitting element 411 and the second light emitting element 412 are semiconductor laser diodes, which are respectively fixed to light emitting element fixing portions 321 and 322 formed integrally with the base 3, and are electrically connected to the circuit board 52a by, for example, wire bonding. It is connected to the. The first light emitting element 411 and the second light emitting element 412 are each composed of, for example, two types of semiconductor laser diodes for CD (compact disc) and DVD (digital video disk). Thereby, this optical pickup device 1 can use each light emitting element properly, and therefore can read information from two types of optical discs 100 of CD and DVD. Here, since the first light emitting element 411 and the second light emitting element 412 have substantially the same function, the first light emitting element 411 will be described below as a representative.

  As shown in FIG. 1, the coupling lens 48, the grating 49, the dichroic prism 43, the collimator lens 44, and the sensor lens 42 are formed so that they can be installed as a unit on the base 3. It is incorporated in the optical holder 40 and installed (mounted) on the base 3.

  The photodiode 46 is mounted on the base 3 via a photodiode holding member 33 bonded to the pin member 22 provided in the module mounting portion 21.

  In the above description, the photodiode holding member 33 is bonded to the pin member 22 and mounted on the base 3. However, the photodiode holding member 33 may be fixed to the optical holder 40 on the base 3 by space bonding.

  Further, a front monitor (not shown) is installed in the vicinity of the optical system 4 in the module mounting portion 21.

In the optical system 4, the laser light 47 a oscillated from the first light emitting element 411 is received by the photodiode 46 through the following parts.
First, the laser light 47 a is emitted from the first light emitting element 411.

  Next, the laser beam 47 a is collected by the coupling lens 48, diffracted by the grating 49, and enters the dichroic prism 43.

  Next, the laser light 47 a passes through the dichroic prism 43 and travels toward the collimator lens 44.

  Next, the laser light 47a becomes parallel light by the collimator lens 44, is reflected by the reflecting mirror 45, and passes through an objective lens (not shown) held by a lens holder (not shown). Thereafter, a recording layer (not shown) on which information in the optical disc 100 is recorded is irradiated.

  Next, the reflected light 47b reflected by the optical disk 100 (recording layer) passes through the objective lens, is reflected by the reflecting mirror 45, becomes parallel light by the collimator lens 44, and enters the dichroic prism 43, contrary to the above. To do.

  Next, the reflected light 47 b is reflected by the dichroic prism 43, passes through the sensor lens 42, and is received by the photodiode 46.

  With such a configuration, information stored in the optical disc 100 is obtained and reproduced based on the optical signal detected by the photodiode 46.

  As shown in FIG. 1, the drive circuit 5 includes a driver IC 51 and a circuit board 52a, and is a circuit that drives the first light emitting element 411 and the second light emitting element 412 of the optical system 4.

  As shown in FIG. 3, the driver IC 51 is a semiconductor chip, and is fixed so that the bottom surface 511 is in contact with the base 3. Although this fixing method is not particularly limited, it can be fixed by, for example, soldering or bonding with an adhesive.

  The circuit board 52a is a flexible board, and surrounds the periphery of the driver IC 51, that is, a hole corresponding to the shape of the driver IC 51 is provided at a position where it interferes with the driver IC 51, and is fixed to the base 3 by thermocompression bonding. Has been. On the circuit board 52a, a circuit pattern related to an electric signal input to the driver IC 51 is printed. The driver IC 51 and the circuit board 52 a are electrically connected by wire bonding 53.

  In the optical pickup device 1 having such a configuration, when the driver IC 51 generates heat when it is operating, the heat is directly transmitted from the driver IC 51 to the base 3 and released into the air.

  Thereby, the cooling efficiency of the driver IC 51 can be increased as compared with the conventional optical pickup device that radiates heat through the shield case. That is, the heat generated from the driver IC 51 can be radiated efficiently.

  Further, in this optical pickup device 1, since the base 3 is made of a metal material and the driver IC 51 is installed in direct surface contact with the base 3, the thermal resistance can be reduced. Therefore, the heat transfer efficiency from the driver IC 51 to the base 3 is high, and the cooling efficiency of the driver IC 51 can be further increased.

  Further, since the base 3 has a sufficiently larger volume than the driver IC 51 (see FIGS. 1 and 2), its heat capacity is sufficiently larger than that of the driver IC 51. Thereby, the cooling efficiency of the driver IC 51 can be further increased.

  Further, since the driver IC 51, the first and second light emitting elements 411 and 412, the optical system 4, and the circuit board 52a are mounted on the base 3 as a unit, the optical pickup device 1 can be reduced in size and thickness. It is something that can be done.

  In addition, since the housing 2 has a frame shape and a cavity is provided in the housing 2 to form the module mounting portion 21 and the base 3 is fixed thereto, the optical pickup device 1 can be reduced in weight. It is.

  Further, since the unit as described above can be assembled on the housing 2 by screwing, the assembly becomes easy and the workability can be improved.

  Furthermore, since the optical axis adjustment of the optical system 4 can be adjusted separately from the housing 2, the optical axis adjustment is facilitated.

  Further, the residual heat is transmitted to the housing of the drive mechanism through the drive shaft 23 and released into the air.

  In the optical pickup device 1, heat radiating means such as heat radiating fins may be provided on the base 3. Thereby, the heat transmitted from the driver IC 51 to the base 3 can be more efficiently released into the air through the heat radiation fins. Therefore, the cooling efficiency of the driver IC 51 can be further increased.

It is a perspective view which shows the outline | summary of the optical pick-up apparatus of this invention. It is a top view which shows the driver IC vicinity installed in the optical pick-up apparatus shown in FIG. It is a side view which shows the driver IC vicinity installed in the optical pick-up apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical pick-up apparatus 2 Case 21 Module attachment part 22 Pin member 23 Drive shaft 3 Base 31 Screw 321 and 322 Light emitting element fixing | fixed part 33 Photodiode holding member 4 Optical system 40 Optical holder 411 1st light emitting element 412 2nd light emitting element 42 Sensor lens 43 Dichroic prism 44 Collimator lens 45 Reflector 46 Photodiode 47a Laser light 47b Reflected light 48 Coupling lens 49 Grating 5 Drive circuit 51 Driver IC
511 Bottom 52a Circuit board 521 Bottom 53 Wire bonding 100 Optical disc

Claims (4)

On the housing,
A light emitting element that emits laser light;
A light receiving element that receives the reflected light of the laser beam reflected by the optical disc;
An optical element provided between optical paths from the light emitting element to the light receiving element;
An optical pickup device comprising a laser driver for driving the light emitting element,
The optical pickup device, wherein the light emitting element, the optical element, and the laser driver are fixed on a base made of a metal material and further mounted on the casing. A circuit board provided with a through hole at a position corresponding to the laser driver,
The bottom surface of the laser driver is fixed in direct contact with the base through the through hole,
The optical pickup device according to claim 1, wherein the circuit board is fixed to the base surface so as to surround the laser driver and is connected to the laser driver. The optical element is
A coupling lens for condensing the laser beam;
A grating that diffracts the focused laser beam;
A dichroic prism that reflects or transmits the diffracted laser light and the reflected light;
A collimator lens that collimates the diffracted laser light and the reflected light, and
The optical pickup device according to claim 1, further comprising: a sensor lens that collects the reflected light on the light receiving element. The base and the light receiving element are fixed to a module mounting portion of the housing,
4. The optical pickup device according to claim 1, wherein the module mounting portion is formed by forming the casing in a substantially frame shape, and the inside thereof is hollow.

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