JPH0563309A - Semiconductor laser device - Google Patents

Abstract

PURPOSE:To make the title semiconductor laser device compact and lightweight. CONSTITUTION:The title semiconductor laser device is proved with a laser beams monitoring PD 2 formed on a Si substrate 12, an LD chip 1 and the electrodes 13, 14 required for the LD chip 1 provided on the Si substrate 12 as well as a common electrode 16 formed on the whole rear region of the Si substrate 12. Furthermore, a transparent plate 17 transmitting the outgoing laser beams is fixed to the stepped end face on the laser beam outgoing side end of the Si substrate 12 while the space between the LD chip 1 and the transparent plate 17 as well as the whole surface of the LD chip 1 and the PD 2 is covered with a transparent region 18 so that the title compact and lightweight semiconductor laser device may be manufactured at low cost without using any heavy parts at all.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device having a simple structure.

[0002]

2. Description of the Related Art A semiconductor laser device is used as a light source of an optical head such as a laser disk or a compact disk player, and an example of its structure is shown in FIG. FIG. 3 is a partially peeled perspective view of a conventional semiconductor laser device. A laser diode (hereinafter, referred to as LD) chip 1 is provided with a photodiode (hereinafter, referred to as PD) 2 for monitoring an output of the sub-mount 3. Soldered on.
The submount 3 is adhered to the heat sink 5 integrated on the metal base 4 with silver paste or the like in order to dissipate the Joule heat during the operation of the LD chip 1. The LD chip 1 and the PD 2 each have one common terminal 6
, And the other terminal is wire connected to the respective posts 7, 8. Then, the LD chip 1 and the PD 2 are sealed on the metal base 4 in a metal can 10 having a glass window 9. Several notches 11 are formed on the periphery of the metal base 4 and are used as positioning when mounting the semiconductor laser device. That is, for example, when the semiconductor laser device is used for an optical head or the like, the required optical adjustment can be performed by attaching the metal base 4 to a jig specific to the optical head and moving the jig.

[0003]

The problems with the conventional semiconductor laser device as described above are as follows. The equipment to which the semiconductor laser device such as an optical head is applied is being made smaller and lighter, and the semiconductor laser device itself is also small,
There is a need for weight reduction. On the other hand, most of the size and weight of the conventional semiconductor laser device is occupied by the metal base 4 and the metal can 10, and the reduction in size and weight of these is almost reached.

The present invention has been made in view of the above points, and an object of the present invention is to provide a semiconductor laser device which is smaller and lighter in weight.

[0005]

In order to solve the above-mentioned problems, a semiconductor laser device of the present invention includes a PD for monitoring a laser beam formed on a Si substrate, an LD chip provided on the Si substrate, and It has a necessary electrode and a common electrode formed over the entire back surface of the Si substrate, and a transparent plate for transmitting the emitted laser light is attached to the stepped end face of the laser light emitting side end of the Si substrate to form an LD chip. Between the transparent plate,
In addition, the entire surface of the LD chip and PD is covered with a transparent resin.

[0006]

Since the semiconductor laser device of the present invention is configured as described above, the Si substrate on which the LD chip is mounted can have a positioning reference without using the conventional metal stem and metal can. Since the most expensive parts that were used in the conventional semiconductor laser device itself are omitted, low cost is realized, and the overall shape is extremely small and lightweight, so the optical head to which this device is applied It is also possible to achieve small size and light weight.

[0007]

EXAMPLES The present invention will be described below based on examples. FIG. 1 is a perspective view showing the structure of a semiconductor laser device according to the present invention, and the same parts as those in FIG. 3 are designated by the same reference numerals. Figure 1
In FIG. 1, the LD chip 1 is provided on a silicon (Si) substrate 12 which is also used as a positioning reference, and a PD 2 for monitoring the output of the LD chip 1 is provided on the Si substrate 12 as well as a PD electrode. 13, LD electrode 14
And the LD chip 1 and the LD electrode 14 have the lead wire 1
Soldering with 5. A common electrode 16 is formed on the back surface of the Si substrate 12. The electrical connection relationship of each of these members is shown in FIG. 2, which will be described later.

On the laser light output side of the Si substrate 12, a transparent plate 17 that transmits the laser light is attached to the end face where a step is formed so as not to block the laser emission light. Therefore, the laser light emitting surface of the LD chip 1 and the transparent plate 17 have a space. Then, while covering the entire surfaces of the PD 2 and the LD chip 1, a transparent resin 18 capable of transmitting laser light is applied so as to fill the space between the laser light emitting surface of the LD chip 1 and the transparent plate 17. This is because the transparent plate 17 does not disturb the light emission characteristic (far field pattern), and the transparent resin 18 exposes the LD chip 1 to the outside air,
The purpose is to prevent oxidation and deterioration. When incorporated in an optical head or the like, it is mounted with a conductive adhesive on a jig that fits the corners or edges of the Si substrate 12 of this device.

Since the internal structure of the Si substrate 12 and the LD chip 1 and the details of each electrode cannot be shown in FIG. 1, in order to clarify the electrical connection relationship of the device of the present invention, FIG. ) Shows a schematic sectional view, and FIG. 2B shows an equivalent circuit. 2 (a) uses the same symbols as in FIG. 3, but L
In this example, one D chip 1 and one PD 2 are connected. Figure 2
In (a), n-type Si is used for the Si substrate 12, and the region converted to p-type by a normal semiconductor manufacturing process is PD2, and the p-side electrode 13 of PD2 connected to the p-type region is Si.
It overhangs on the substrate 12 through the insulating layer 19 to the end portion of the Si substrate 12, and serves as an electrode for external connection. L
The D chip 1 is directly connected to the p-side electrode 20a provided on the Si substrate 12, and has the same potential as the common electrode 16 on the back side of the Si substrate 12. The n-side electrode 20b provided on the opposite side of the LD chip 1 is soldered to the LD electrode 14 provided on the Si substrate 12 via the insulating layer 21 using the lead wire 15. An equivalent circuit is shown in FIG. 2B, which is the same as the normal case, as in the relationship between the LD and PD of the conventional device shown in FIG.

As described above, the semiconductor laser device of the present invention has the P for monitoring the laser light from the LD chip.
D, two electrodes connected to it, and two for the LD chip
The LD chip is soldered at a predetermined position on the Si substrate provided with the individual electrodes, and the electrode on the opposite side of the LD chip and the other LD electrode on the Si substrate are connected by wire bonding. On the laser light output side of the LD chip, a transparent plate is attached to the end surface of the Si substrate on which the step is formed, and this transparent plate transmits all the laser light. The surfaces of the PD and the LD chip are thickly covered with a transparent resin, and this resin is also filled between the light emitting surface of the LD chip and the transparent plate. In this device configuration, a Si substrate on which an LD chip is mounted has a positioning reference without using a conventional metal stem and metal can.

[0011]

The size and weight of the conventional semiconductor laser device are determined by the metal base and the metal can that occupy most of them, but in the present invention, as described in the embodiment, S
Since the PD and the LD chip are mounted on the i-substrate and covered with the transparent resin, it is not necessary to use heavy parts, and the size and weight can be extremely reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing the configuration of a semiconductor laser device of the present invention.

2A is a schematic cross-sectional view of a semiconductor laser device of the present invention, and FIG. 2B is an equivalent circuit diagram thereof.

FIG. 3 is a partially peeled perspective view of a conventional semiconductor laser device.

[Explanation of symbols]

 1 LD Chip 2 Photodiode 3 Submount 4 Metal Base 5 Heat Sink 6 Common Post 7 Post 8 Post 9 Glass Window 10 Metal Can 11 Notch 12 Si Substrate 13 PD Electrode 14 LD Electrode 15 Lead Wire 16 Common Electrode 17 Transparent Plate 18 Transparent Resin 19 Insulating layer 20a LD p-side electrode 20b LD n-side electrode 21 Insulating layer

Claims (3)

[Claims] 1. A photodiode formed on a silicon substrate for monitoring laser light and its electrode, a laser diode chip electrically connected to the silicon substrate and its electrode, and mounted on an end face of the silicon substrate on the laser light emitting side for emission. A semiconductor laser device comprising: a transparent plate sized to allow all laser light to pass therethrough, a transparent resin covering the entire front surface of the laser diode chip and the photodiode, and a common electrode formed over the entire back surface of the silicon substrate. .. 2. The semiconductor laser device according to claim 1, wherein a transparent plate is attached to an end surface of a step portion formed at an end portion of the silicon substrate on the laser light emitting side. 3. The semiconductor laser device according to claim 1 or 2, wherein a gap between the laser diode chip and the transparent plate is filled with a transparent resin.