JPH04320386A - Semiconductor laser - Google Patents

Abstract

PURPOSE:To maintain high beam characteristic irrespective of a variation in an environment in a can-sealed type semiconductor laser and to provide an inexpensive laser. CONSTITUTION:A transparent plate 7 for emitting a laser beam is adhered to an end of a protrusion 4 provided at a stem 2 with adhesive 8 in a noncontact state with a cap body 3, and transparent synthetic resin 9 is so filled between the plate 7 and the protrusion 4 as to cover a semiconductor laser chip 6.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to an improvement of a can-seal type semiconductor laser device, which uses a semiconductor laser chip as a laser light emitting element, and in which a portion of the semiconductor laser chip is covered with a cap body. It is related to.

0002

[Prior Art] This type of can-seal type semiconductor laser device has a semiconductor laser chip mounted on the side surface of a protrusion provided on a metal stem, with the front cleavage plane, which is the laser beam emission surface, facing the protrusion direction of the protrusion. A cap body having a window hole for laser beam emission is fitted onto the protrusion, and this cap body is fixed to the stem.

[0003] Conventionally, as a means for emitting a laser beam to the outside while protecting the semiconductor laser chip from atmospheric moisture and dust, there is a method described in, for example, Japanese Utility Model Application Laid-Open No. 62-58066. As shown in the figure, while the cap body is fixed to the stem in a sealed state, a transparent plate made of glass that closes the window hole in the cap body is sealed with glass solder at the location of the window hole. By fixing the cap, the inside of the cap is kept secret, or the inside of the cap is filled with transparent synthetic resin.

0004

[Problem to be Solved by the Invention] If a method is adopted in which, as in the former case, a transparent plate that closes the window hole is fixed to the cap body with glass solder to seal the inside of the cap body, the glass Since the laser beam can be emitted through the smooth transparent plate, it has the advantage of ensuring high beam characteristics.

However, on the other hand, in order to fix the transparent plate to the cap body with glass solder, the glass solder is manufactured in the shape of a ring, which is inserted between the transparent plate and the cap body, and then heated at high temperature. In addition to requiring a great deal of effort in the glass solder manufacturing process and firing process, the cap body, which had discolored due to firing at high temperatures, had to be acid-washed and then nickel plated. Since this requires a post-processing step, the cost of fixing the transparent plate to the cap body increases, resulting in a problem in that the price of the semiconductor laser device increases significantly.

Furthermore, in order to prevent cracks from occurring in the glass solder due to the difference in coefficient of thermal expansion between the glass solder and the cap body, the cap body is made of a special metal with a coefficient of thermal expansion close to that of glass. Not only does it have to be used, but also strict process control is required to fix the cap body to the stem in a sealed state, which further increases manufacturing costs.

On the other hand, the latter method of filling the inside of the cap with transparent synthetic resin requires a glass solder manufacturing process, a high-temperature firing process, and pickling and plating processes as post-processing. A simple process of filling the synthetic resin into the cap body and curing it by drying etc. is sufficient, and the cap body does not need to be fixed to the stem in a completely sealed state, which significantly reduces manufacturing costs. It has the advantage of being able to reduce

However, on the other hand, synthetic resins
There is a problem in that it is difficult to form the outer surface into a smooth surface by drying or other hardening, and it is also easily damaged, making it difficult to obtain high beam characteristics. Another problem was that the stability of the beam characteristics was low because stress was applied to the synthetic resin due to thermal expansion of the cap body, causing distortion in the synthetic resin.

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor laser device that can stably maintain high beam characteristics at a low cost.

0010

[Means for Solving the Problems] In order to achieve this object, the present invention fixes a semiconductor laser chip to the side surface of a protrusion provided on a stem with the laser beam emission surface facing in the protruding direction of the protrusion. In the semiconductor laser device, a cap body that fits on the protrusion is fixed to the stem, and a transparent plate is disposed inside the cap body, and the transparent plate is provided on the tip end surface of the protrusion in the stem. The semiconductor laser chip is fixed to the cap body with an adhesive in a non-contact state, and a transparent synthetic resin is filled between the transparent plate and the side surface of the protrusion so as to cover the semiconductor laser chip.

[0011]

With this structure, the laser beam from the semiconductor laser chip passes through the transparent synthetic resin and is emitted to the outside from the transparent plate. High beam characteristics can be obtained because of the high beam quality. In addition, the semiconductor laser chip is reliably protected from moisture and dust by a transparent synthetic resin, and the transparent plate is glued to the protrusion, and the distance between the semiconductor laser chip and the transparent plate and the orientation of the transparent plate are also important. is maintained in a predetermined state, and the transparent plate and transparent synthetic resin are in a non-contact state with the cap body, so that even if the cap body expands thermally, distortion will occur in the transparent plate and transparent synthetic resin. The combination of these three factors means that high beam characteristics can be stably maintained without being affected by changes in the external environment such as temperature changes.

Furthermore, since a gap is formed between the inner surface of the cap body and the transparent plate, external impact acting on the cap body is prevented from directly acting on the transparent plate and the semiconductor laser chip. The impact resistance of the laser chip device can also be improved. Since there is no need to consider the adverse effects of thermal expansion for the cap body, inexpensive materials such as steel plates can be used, and since there is no need to fix the cap body in a sealed state to the stem, the cap body can be fixed to the stem. The cost of manufacturing and installing these cap bodies can be reduced significantly, and the transparent plate can be easily adhered to the protrusion with an adhesive.
Filling with a transparent synthetic resin can be carried out extremely easily by using a synthetic resin that hardens upon drying, a thermosetting synthetic resin, etc., and together with this, manufacturing costs can be significantly reduced.

Therefore, according to the present invention, a semiconductor laser device that can maintain high beam characteristics without being affected by environmental changes and has improved impact resistance can be provided at a low cost.

[0014]

Embodiments Next, embodiments of the present invention will be described based on the drawings. In the figure, reference numeral 1 indicates a semiconductor laser device including a stem 2 formed into a disk shape from metal such as carbon steel, and a metal cap body 3 having a window hole bored at its upper end. A block-shaped protrusion 4 is integrally formed on the upper surface of the stem 2. A semiconductor substrate 5 is fixed to the side surface of the protrusion 4, and a semiconductor laser chip 6 is mounted on the semiconductor substrate 5 in front thereof. Die bonding is performed so that the cleavage plane 6a (laser beam emission surface to the outside) faces the protrusion direction of the protrusion 4, and the rear cleavage plane 6b faces a monitoring photodiode (not shown) provided on the semiconductor substrate 5. .

Furthermore, a transparent plate 7 made of glass or the like is adhered to the upper surface of the protrusion 4 using an adhesive 8 made of an appropriate material such as epoxy resin, and the cap body is attached to the transparent plate 7 and the protrusion 4. 3
and this cap body 3 is fitted in a non-contact state,
Outward flange portion 3 formed at the lower end of the cap body 3
The entire circumference of b is fixed to the stem 2 by resistance welding to the upper surface of the stem 2.

A transparent and adhesive synthetic resin 9 such as silicone resin is filled between the lower surface of the transparent plate 7 and the side surface of the protrusion 4 so as to cover the semiconductor laser chip 6 . The transparent synthetic resin 9 may be one that hardens upon drying, a thermosetting resin, or a UV resin. Three lead terminals 10 for the semiconductor laser chip 6
, 11, 11 is fixed to the lower surface of the stem 2 by welding, and the other two lead terminals 1 are fixed to the lower surface of the stem 2.
1 and 11 are inserted into the cap body 3 through a through hole formed in the stem 2, and are fixed to the stem 2 by adhesion using glass solder or an adhesive.

With the above configuration, the laser beam from the front cleavage plane 6a of the semiconductor laser chip 6 passes through the transparent synthetic resin 9 and is emitted to the outside from the transparent plate 7 having a smooth surface. , high beam characteristics can be obtained. Furthermore, the semiconductor laser chip 6 is made of transparent synthetic resin 9.
The transparent plate 7 is bonded to the protrusion 4, and the distance between the semiconductor laser chip 6 and the transparent plate 7 and the transparent plate 7 are protected by The posture of the transparent plate 7 can be maintained constant, and the transparent plate 7
and the transparent synthetic resin 9 are in a non-contact state with the cap body 3, so that even if the cap body 3 thermally expands, no distortion occurs in the transparent plate 7 or the transparent synthetic resin 9. Together, this makes it possible to maintain high beam characteristics without being affected by changes in the external environment such as temperature changes.

Furthermore, since the transparent plate 7 is in a non-contact state with respect to the cap body 3, external impact acting on the cap body 3 is prevented from directly acting on the transparent plate 7 and the semiconductor laser chip 6. , the impact resistance of the semiconductor laser chip device can also be improved. Since the cap body 3 does not need to take into account the adverse effects of thermal expansion, it is possible to use an inexpensive material such as a steel plate, and since it does not need to be fixed to the stem 2 in a sealed state, the cap body 3 The effort required to fix it to the stem 2 can be significantly reduced,
It is possible to reduce the cost of manufacturing and attaching these cap bodies 3, to be able to easily adhere the transparent plate 7 to the projections 4 with adhesive, and to cover the semiconductor laser chip 6 with the transparent synthetic resin 9. Coupled with the fact that this can be done extremely easily by dropping a synthetic resin that hardens upon drying, a thermosetting synthetic resin, etc. in a liquid state, manufacturing costs can be significantly reduced.

As shown by the dashed line in FIG. 1, a moisture-impermeable synthetic resin 12 such as a fluororesin may be applied to the surface of the transparent synthetic resin 9. Further, a transparent adhesive may be used as the adhesive 6 for bonding the transparent plate 7 to the protrusion 4. In this case, the adhesive 8 may adhere to the front cleavage surface 6a of the semiconductor laser chip 6. However, since the transmittance of the laser beam is not impaired, there is no need to precisely apply the adhesive 8 when bonding the transparent plate 7, which has the advantage of further reducing the manufacturing effort.

Furthermore, the stem and the cap body are not limited to being made of metal, but may be made of other materials such as synthetic resin, and in this way, both are made of synthetic resin. In some cases, the cap body may be fixed to the stem by heat fusion. Alternatively, the stem may be formed from a metal plate and the protrusions may be formed by cutting and raising them.

[Brief explanation of drawings]

FIG. 1 is a front sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG. 1;

FIG. 3 is a plan cross-sectional view taken along line III--III in FIG. 1;

[Explanation of symbols]

1 Semiconductor laser device 2 Stem 3 Cap body 4 Protrusion 5 Semiconductor substrate 6 Semiconductor laser chip 6a Front cleavage plane (laser beam emission plane) 7
Transparent plate 8 Adhesive 9 Transparent synthetic resin

Claims (1)

[Claims] 1. A semiconductor laser chip is fixed to a side surface of a protrusion provided on a stem with the laser beam emission surface facing in the protrusion direction of the protrusion, and a cap body is fitted to the stem to fit over the protrusion. In the semiconductor laser device, the transparent plate is fixed to the cap body and a transparent plate is disposed inside the cap body. A semiconductor laser device, wherein a transparent synthetic resin is filled between the transparent plate and the side surface of the protrusion so as to cover the semiconductor laser chip.