JPH0424978A - Optical semiconductor element - Google Patents

Abstract

PURPOSE:To realize a thin type by detecting a retaining substrate for fixing a heat dissipating block, a photodetector, and a connection terminal, by using resin capable of molding a unified body. CONSTITUTION:A heat dissipating block 30 retains a semiconductor laser 1 via a silicon substrate 2, retains a photodetector 3 via an insulating plate 4, and dissipates the heat generated by the semiconductor laser 1. A stem 31 retains a heat dissipating block 30 and a photo detector 9 for monitoring and is used as a stem for leading out connection terminals 8 to the outside. The stem 31 is formed by using resin capable of molding a unified body with the heat dissipating block 30. Since the stem 31 is made of resin, a free shape can be designed. Further, since the heat dissipating block 30 penetrates the stem 31, and the bottom surface of the block 30 is fixed so as to be exposed from the bottom surface of the stem 31, the heat generated by a semiconductor laser 1 can be directly dissipated outward via the heat dissipating block 30.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical semiconductor element that is used in optical head devices and the like and has a built-in light emitting element and a light receiving element.

BACKGROUND OF THE INVENTION In recent years, remarkable progress has been made in the development of optical heads as main components of optical disk devices, and in addition to improving the basic performance of recording or reproduction, miniaturization of optical heads has become important. There are various proposals for downsizing technology, but
Among these, an optical semiconductor element that integrates a light source and a photodetector by using a hologram element as an optical element is considered to be the most promising.

Figure 3 ((a) and (b)) is based on Japanese Patent Application Laid-open No. 1-1139
A vertical cross-sectional view of a conventional optical semiconductor element seen in Publication No. 33,
FIG.

In the figure, 1 is a semiconductor laser, 16 is a front-emitted light beam emitted from the semiconductor laser 1 to an optical recording medium (not shown) via a window glass 12 (described later), and 17 is a beam separated from the return light from the optical recording medium (not shown). 18 is a rear emitted light beam emitted from the surface opposite to the surface from which the front emitted light beam 16 of the semiconductor laser 1 is emitted, 2 is a silicon substrate for mounting the semiconductor laser 1, and 3 is a separated light beam 1.
7, a photodetector having a plurality of photodetectors for receiving light;
4 is an insulating plate for mounting the photodetector 3; 5 is an insulating plate that holds the semiconductor laser 1 via the silicon substrate 2, and also holds the photodetector 3 via the insulating plate 4;
6 is a lead wire, 7 is a bonding pad placed on the photodetector 3, and 8 is mounted concentrically on the stem to be described later. 9 is a monitoring photodetector installed below the semiconductor laser 1 on a stem to be described later so that the rear emitted light flux 18 is incident thereon; 10 is a heat dissipation block 5 and A stem that holds the monitoring photodetector 9 and leads out the connection terminal 8 to the outside; 11 is a cap that houses each component installed on the stem 10 and seals it from the outside; 12 is a cap of the cap 11; A window glass 15 attached to a window opened on the top surface is a conventional optical semiconductor element body.

Moreover, FIG. 3(b) is a diagram when the cap 12 is removed.

The operation of the optical semiconductor device configured as described above will be described below. The front-emitting light beam 16 emitted from the semiconductor laser 1 is focused on an optical recording medium (not shown) through the window glass 2, and carries information recorded on this optical recording medium as well as information on focal position errors and track position errors. reflected. The return light from the optical recording medium is separated from the output optical axis into a separated light beam 18, which is then received by the photodetector 3 via the window glass 12 again to detect the information signal, focal position error, and track recorded on the optical recording medium. The position error signal is sent to the bonding pad 7, the lead wire 6. It is output through the connection terminal 8. The monitoring photodetector 9 receives the rear emitted light beam 18 of the semiconductor laser 1, and the amount of the front emitted light beam 16 of the semiconductor laser 1 is indirectly monitored. Further, the semiconductor laser 1 generates a large amount of heat while emitting light, and the generated heat is transmitted to the stem 1O via the thin silicon substrate 2 and the heat radiation block 5 and is emitted to the outside.

FIG. 4 is a schematic diagram of an optical head device using the above-mentioned optical semiconductor element to enable the above-described operation. In the figure, 15 is the above-mentioned optical semiconductor element, 16 is a front-emission light beam emitted from the optical semiconductor device 15, and 20 is an objective lens 21 which reflects the front-emission light beam 16 and changes its direction, which will be described later.
The objective lens 21 is a mirror that guides the front emitted light beam 1.
6 is focused on an information surface on an optical recording medium 25, which will be described later, or return light from the information surface is focused and guided to a mirror 20. The objective lens 21 is attached to a base 23, which will be described later, via an actuator (not shown). 22 is a hologram element 17 installed between the objective lens 21 and the mirror 20 for separating the aforementioned return light from the output optical axis;
23 is a base that holds the optical semiconductor device 15, the mirror 20, and the hologram element 22, and also fixes the objective lens 2 via an actuator (not shown). are doing. 24 is a main body of an optical head device using a conventional optical semiconductor element 15, and 25 is an optical recording medium.

The hologram element 22 not only has the function of separating the returned light from the output optical axis, but also various methods have been proposed to obtain the above-mentioned error signal. For example, it can generate astigmatism to obtain a focal position error signal. is possible.

In such a configuration, the front-emitted light beam 16 emitted from the semiconductor laser 1 built into the optical semiconductor element 15 passes through the mirror 20 . Hologram element 22° The returned light is focused on the optical recording medium 25 through the objective lens 21, intensity-modulated by the information recorded on the optical recording medium 25, and reflected, and then passes through the objective lens 21 again to the hologram element 22. incident on .

The returned light is separated from the optical axis of the emitted light beam by the hologram element 22 due to the diffraction effect, and enters the photodetector 3 built in the optical semiconductor device 15 as a separated light beam 17 . The photodetector 3 has a detection section divided into four parts, for example, and outputs a focal position error signal by using astigmatism of the separated light beam generated by the hologram element 22, and also uses a so-called push-pull method. In addition to outputting a track position error signal, the information signal recorded on the optical recording medium 25 is output by detecting the modulation intensity of the entire separated light beam 17.

Problems to be Solved by the Invention In order to reduce the size of the optical head device having the structure shown in FIG. 4, it is necessary to reduce the size of the optical semiconductor element 15 itself. In particular, when the same objective lens is used, the thickness of the optical head device depends on the thickness of the base 23 (indicated by I in the figure).
It is determined by the width of 0 (indicated by r in the figure). Normal stem 1
0 must be made of a metal with good thermal conductivity, so
Considering the workability of the metal, it is necessary to use a disk-shaped one. However, as shown in FIG. 4, in the optical semiconductor device having the above-mentioned configuration, the heat dissipation block 5 and the monitoring photodetector 9 are arranged side by side, and the width (hereinafter referred to as the y direction) in the direction in which they are lined up ( The width (denoted by Ll) is significantly larger than the width (denoted by L2) in a direction perpendicular to this (hereinafter referred to as the X direction), and the width r of the stem 10 described above cannot be made smaller. In other words, there is a problem in that there is a limit to the miniaturization of optical head devices, particularly to the reduction in thickness, with optical semiconductor devices having conventional configurations.

SUMMARY OF THE INVENTION Therefore, the present invention provides an optical semiconductor element that can reduce the width r of the stem and thus realize an optical head device that is thinner than the conventional optical head device.

Means for Solving the Problems In order to solve the above problems, the optical semiconductor device of the present invention includes a semiconductor laser, a heat dissipation block made of a thermally conductive material for holding the semiconductor laser, and a device that monitors the output light amount of the semiconductor laser. A monitoring photodetector, a connection terminal for supplying power to the semiconductor laser or outputting the detection current of the photodetector to the outside, and a heat dissipation block for fixing the photodetector and connection terminal can be integrally molded. The heat dissipation block has a structure in which the heat dissipation block is fixed by penetrating the support substrate and exposing the bottom surface from the bottom surface of the support substrate.

Effects According to the above configuration, the shape of the support substrate can be freely designed by molding the support substrate, which determines the external dimensions of the optical semiconductor element of the present invention, from a resin that can be integrally molded.

Therefore, by designing the shape of the support substrate in accordance with the shape of the heat dissipation block etc., the optical semiconductor element of the present invention itself can be miniaturized, and as a result, an optical head device using the optical semiconductor element of the present invention can be achieved. It is possible to make the device smaller, especially thinner.

EXAMPLE Hereinafter, a first example of the present invention will be described with reference to the drawings.

FIGS. 1(a), (b) and (c) are the first embodiment of the present invention.
FIG. 3 is a vertical cross-sectional view and a plan view of an optical semiconductor element in an example.

It is a bottom view.

The optical semiconductor device of this example shown in the figure basically consists of a third
Since it has the same configuration as the conventional optical semiconductor device shown in the figure,
Identical components are given the same numbers and detailed explanations will be omitted.

To explain the differences from the conventional example, 30 holds the semiconductor laser 1 via the silicon substrate 2, and also holds the photodetector 3 via the insulating plate 4, and has a heat conduction plate 30 to release the heat generated from the semiconductor laser 1. This is a heat dissipation block made of a material with good properties, and as shown in FIG. 1(C), it is installed so as to penetrate the bottom surface of a stem 31, which will be described later. Further, 31 is a heat dissipation block 30 and a monitoring photodetector 9.
It is a stem for holding the connection terminal 8 and guiding the connection terminal 8 to the outside, and is made of resin that can be integrally molded with the heat dissipation block 30. Reference numeral 32 designates a cap for accommodating each component installed on the stem 31 and sealing it off from the outside world, and is made of the same resin as the stem 31. 33 is the main body of the optical semiconductor element of this example.

The basic operation of the optical semiconductor device of this example configured as described above is the same as that of the conventional optical semiconductor device described above, but in the optical semiconductor device of this example, the stem 31 is made of resin. Since it is made of aluminum, it is possible to design any shape. However, the heat radiation block 30 is fixed by penetrating the stem 31 and exposing its bottom surface from the bottom surface of the stem 31.Sixth, the heat generated by the semiconductor laser 1 is directly radiated to the outside through the heat radiation block 30. Therefore, even if the stem 31 is formed using a resin having poor thermal conductivity, the semiconductor laser 1 will not be damaged due to poor thermal conduction.

Of course, the cap 32 can also be made of resin C and formed into a shape corresponding to the stem 31.

In addition, normally in an optical semiconductor device such as this embodiment, a printed circuit board is attached to the stem 31 for connection to an external electric circuit.
The connection terminal 8 is soldered to the copper foil on the printed circuit board, but if the heat dissipation block 30 is brought into contact with the copper foil on the ground side of the printed circuit board at this time, the heat dissipation will be more ensured. It can be done.

Furthermore, since the optical semiconductor device of this embodiment is made of resin for the stem 30 and cap 32, the weight can be reduced, and it is expected that the seek time of an optical head device using this device will be shortened.

FIGS. 2(a), (b) and (c) are the second embodiments of the present invention.
FIG. 3 is a vertical cross-sectional view and a plan view of an optical semiconductor element in an example.

It is a bottom view.

The optical semiconductor device of this embodiment shown in the figure has the same configuration as the optical semiconductor device of the first embodiment of the present invention shown in FIG. A detailed explanation of the configuration and operation will be omitted. The difference from the first embodiment is that 34 is a stem as shown in FIG. It has a shape in which both sides of the circumference are sinusoidally cut in the aforementioned X direction,
The connection terminals 8 are arranged on both sides of the heat dissipation block 30 and the monitoring photodetector 9. Further, the cap 37 is made of the same resin as the stem 34 in order to accommodate each component installed on the stem 34 and seal it from the outside world.

36 is the main body of the optical semiconductor element of this embodiment.

By adopting such a configuration, the width r of the stem 34 in the X direction can be made smaller than that of a disk-shaped stem.
Therefore, it is possible to reduce the thickness of an optical head device using this.

In order to form the stem 34 into such a shape, it is difficult to process a metal stem like a conventional optical semiconductor element, and there are problems in terms of mass production and cost.

On the other hand, if the resin is integrally molded as in this embodiment, mass production can be performed at low cost simply by creating a mold.

In the above embodiments, a so-called hybrid optical semiconductor device is described in which a semiconductor laser 1, a monitoring photodetector 9, and a photodetector 3 for receiving return light from an optical recording medium are arranged in the same package. However, a similar effect can be obtained with an optical semiconductor device in which only a semiconductor laser and a monitoring photodetector are arranged in the same package.

Effects of the Invention As described above, according to the present invention, the shape of the support substrate can be freely designed by forming the support substrate for fixing the heat dissipation block, photodetector, and connection terminal from a resin that can be integrally molded. Therefore, the present optical semiconductor device can be made thinner, and an optical head device using the same can also be made thinner.

Furthermore, since the heat dissipation block is exposed and fixed from the bottom surface of the support substrate, the heat generated by the semiconductor laser is radiated to the outside from the bottom surface of the optical semiconductor element, and there is no problem of damage to the semiconductor laser due to heat generation.

[Brief explanation of drawings]

FIGS. 1(a), (b) and (c) are the first embodiment of the present invention.
FIG. 3 is a vertical cross-sectional view and a plan view of an optical semiconductor element in an example. The bottom view, and FIGS. 2(a), 2(b), and 2(C) are longitudinal cross-sectional views of an optical semiconductor device according to a second embodiment of the present invention. 3(a) and 3(b) are a vertical cross-sectional view and a plan view of a conventional optical semiconductor element, and FIG. 4 is a schematic diagram of an optical head device using a conventional optical semiconductor element. . 1... Semiconductor laser, 3... Photodetector, 8
...Connection terminal, 9...Monitoring photodetector,
3o... Heat dissipation block, 31.34... Stem. Name of agent: Patent attorney Shigetaka Awano Haka 1 person

Claims (3)

[Claims] (1) A semiconductor laser, a heat dissipation block made of a thermally conductive material for holding the semiconductor laser, a photodetector for monitoring the output light amount of the semiconductor laser, and supplying power to the semiconductor laser, or A connection terminal for outputting the detection current of the photodetector to the outside, and a support substrate for fixing the heat dissipation block, the photodetector, and the connection terminal, and the support substrate is made of resin that can be integrally molded. An optical semiconductor device characterized by comprising: (2) The optical semiconductor device according to claim 1, wherein the heat dissipation block penetrates the support substrate and has a bottom surface exposed from the bottom surface of the support substrate. (3) The optical semiconductor device according to claim 1, wherein the support substrate has a shape obtained by cutting out at least one part of a disk in a sinusoidal shape.