JPH04280487A - Semiconductor laser equipment - Google Patents

Abstract

PURPOSE:To improve positioning accuracy regardless of the resin for molding an LD (laser diode element) by a method wherein a bending section is formed on a lead frame in the direction parallel or vertical to the emitting direction of the laser light, and the bending section is used as a reference for the positioning. CONSTITUTION:A part of the two sides of a lead frame 8 is bent so that it is parallel and symmetrical from an LD chip 1 to the direction of the emitted laser light viewed from the front. The LD consisting of a sub-mount 2, a chip 1, and a photo-diode is soldered on the main plane of a lead frame that is formed by the bent both sides and becomes a dented bottom of the lead frame 8. In this instance, the LD and the lead frame 8 are arranged so that their center line coincides with respect to the emitting direction of the laser, thereby improving the relative position between the LD chip 1 and the positioning section of the translucent resin 6 to be molded.

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 in which a laser diode chip is molded with resin.

0002

2. Description of the Related Art Since semiconductor laser devices are used as light sources for optical pickups such as laser disc players and compact disc players, there is a strong demand for low cost. However, conventional semiconductor laser devices are hermetically sealed types whose main components include a metal cap, stem, base, etc. When assembling these components, for example, the leads are passed through the base through insulating glass. The base must be fixed to the stem to which the laser diode element and submount are bonded, and a metal cap with a light transmission hole formed from a transparent plate must be electrically welded to the stem.
Troublesome steps cannot be avoided, and the number of manufacturing steps is extremely large, making it extremely difficult to make such a semiconductor laser device at a low price.

On the other hand, for example, Japanese Patent Laid-Open No. 2-1256
No. 87 discloses a structure in which a part of the laser diode element and its connecting conductor is sealed with a translucent resin, thereby eliminating the need for a metal cap, stem, base, etc.
There is no need for the troublesome process of assembling these parts.
It is stated that the cost of semiconductor laser devices can be significantly reduced.

FIG. 8 is a schematic perspective view of a mold portion of a lead frame resin mold type semiconductor laser device. In FIG. 8, a chip 1 of a laser diode element (hereinafter referred to as LD) is soldered onto a submount 2, and in addition to the LD chip 1, the submount 2 also has a photo-optical device for monitoring the output power of the LD chip 1. A diode 3 is attached, and this submount 2 is attached to the LD chip 1.
It is soldered to the lead frame 4a on the back side of the side where the photodiode 3 is provided. The electrodes formed on the surfaces of both the LD chip 1 and the photodiode 3 are connected to a lead frame 4b by a lead wire 5.
and 4c. And these LD chips 1
, the submount 2, the photodiode 3, the lead frame 4a, and the lead wire 5 are integrally molded with a translucent resin 6, and the translucent resin 6 has a flange shape in some areas including the lead frames 4b and 4c. A section 7 is formed. This flange-shaped portion 7 serves as a reference for positioning the light source when a laser beam is used as a light source. Laser light emitted from the light emitting end face 1a of the LD chip 1 of the semiconductor laser device configured in this manner is emitted to the outside from approximately the center of the circular surface 6a of the transparent resin 6.

[0005]

The simplified resin mold type semiconductor laser device shown in FIG. 8 also has the following problems with regard to assembly.

[0006] When molding the translucent resin 6,
Whether it's transfer molding or casting,
It is difficult to increase the relative positional accuracy between these molds and the lead frames 4a to 4c. That is, in order for the light-transmitting resin 6 to be properly molded in the semiconductor laser device having the structure shown in FIG. The resin molding must be carried out so that the conditions that the light emitting point is parallel to the circular plane part and the light emitting point is on the normal line of the center of the circular plane part of the brim part 7, but in order to satisfy these conditions, It is necessary to position the lead frames 4a to 4c with high precision with respect to the mold, which is extremely difficult. Therefore, it is not possible to ensure high positional accuracy of the laser beam, that is, high positional accuracy of the LD chip 1, due to the flange-shaped portion 7 that serves as a reference for positioning the light source. This brings about the inconvenience of inevitably increasing the size.

A semiconductor laser device is used as a point light source, such as a light source for a compact disc, and produces a point image on the disc. Therefore, it is necessary that there be no non-uniformity between the light exit surface 1a of the LD chip 1 and the point image that would disturb the light wavefront. The limit of this non-uniformity is λ/1
0 (λ is the wavelength of the laser beam) or less. Therefore, the smoothness of the circular end surface 6a of the translucent resin 6 is important, but it is difficult to create a flat surface with the above-mentioned precision on the circular end surface 6a, and even if this is possible, the resin is soft and easily scratched. Another problem is that it is difficult to maintain the flatness accuracy.

The present invention has been made in view of the above points, and its purpose is to improve the accuracy of the relative position between the LD chip and the positioning part of the molded resin, and to provide a semiconductor in which the smoothness of the laser beam emitting surface is ensured. The purpose of the present invention is to provide a laser device.

[0009]

[Means for Solving the Problems] In order to solve the above problems, the semiconductor laser device of the present invention has a resin in a recess formed by bending a part of the lead frame from both sides parallel to the laser beam emission direction. The molded LD is located,
Or, based on a structure in which a resin-molded LD is located inside a bent part that has a laser beam transmission hole formed by bending a part of the lead frame in the direction perpendicular to the laser beam emission direction near the LD chip, In addition, there is a structure in which high transmittance glass is attached to the bent part, and an LD
The structure also allows attachment of another optical element to a bent portion formed in the lead frame extending from the position in the laser beam emission direction.

0010

[Operation] Since the semiconductor laser device of the present invention is configured as described above, it is provided with a bent portion formed on the lead frame, and this bent portion is used as a positioning reference for the device using the semiconductor laser device. be able to. In other words, the lead frame itself serves as a reference for accurately determining the laser beam emission position, and its positioning is completely unrelated to the translucent resin that molds the LD, so it does not depend on the flanges of the mold resin as in the past. This eliminates the occurrence of positioning instability that previously existed. It is also possible to attach high transmittance glass to the end face of the recess formed by bending the lead frame to increase the smoothness of the laser beam emitting surface and to prevent the resin from being damaged. Furthermore, the resin molding process is extremely simple; for lead frames without glass attached to the bent portions, a simple L-shaped mold can be used; for those with glass attached to the bent portions of the lead frames, It can be done without a mold. Further, by forming a plurality of bent portions on the extended portion of the lead frame and attaching other optical elements thereto, it is possible to make a multipurpose device by combining them.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The semiconductor laser device of the present invention is fundamentally different from the conventional semiconductor laser device shown in FIG. 8 in that the lead frame is bent and the lead frame itself is used as a positioning member. The present invention will be explained below based on various examples.

FIG. 1 is a schematic diagram showing an embodiment of a semiconductor laser device according to the present invention, and parts common to those in FIG. 8 are denoted by the same reference numerals. In FIG. 1, this semiconductor laser device is
Parts of the two sides of the lead frame 8 are bent so that they are parallel to the direction in which the laser beam is emitted from the LD chip 1 and are symmetrical when viewed from the front, and a recess in the lead frame 8 is formed by the bent sides. An LD consisting of a submount 2, a chip 1, and a photodiode 3 is soldered onto the main plane of the lead frame 8, which is the bottom surface. At this time, the LD and lead frame 8
must be placed so that their center lines coincide with each other. The LD chip 1 and the photodiode 3 are connected by lead wires 5 to two electrodes 9 extending from the vicinity of the submount 2 to an unbent area on the main plane of the lead frame 8. 10 is an insulating layer. The molded translucent resin 6 seals part of the LD and lead wires 5, and fills almost the entire recess of the lead frame 8. The laser beam emitting surface of the translucent resin 6 forms a highly precise plane, but this surface and two surfaces of the translucent resin 6 other than the surface in contact with the lead frame 8, namely the upper free surface and the laser beam emitting surface, The free surface on the opposite side does not necessarily have to be shaped.

FIG. 2 is a schematic diagram of a semiconductor laser device in which the lead frame 8a is similarly bent, but unlike FIG. 1, the bent portion is oriented perpendicular to the laser beam emission direction. Note that the lead wires 5 and the insulating layer 10 shown in FIG. 1 are not shown in each of the figures after FIG. 2. In this semiconductor laser device, the method of attaching the LD to the lead frame 8a is basically the same as that shown in FIG. 1, but since the bent portion is perpendicular to the laser beam emission direction, the laser beam A light exit hole 11 for taking out the light to the outside is provided in a bent portion of the lead frame 8a. To extract the laser light to the outside, a notch may be formed in the bent portion of the lead frame 8a instead of the light exit hole 11.

Next, a method of molding the transparent resin 6 into the semiconductor laser device having the structure shown in FIGS. 1 and 2 will be described. FIG. 3 is a schematic diagram showing only the parts necessary for explaining the method. Here, the case where the semiconductor laser device of FIG. 1 is molded is shown, and the positional relationship between the L-shaped mold 12 and the lead frame 8 to be used is shown. In FIG. 3, the end surface of the lead frame 8 on the LD chip 1 side, on which the LD and lead wire 5 have been attached, is brought into contact with one inner wall surface 13 of the L-shaped mold 12, and the bent both sides A resin droplet 15 is dropped from the resin reservoir 14 into the opening of the recess of the formed lead frame 8 in the direction of gravity shown by the arrow. At this time, the L-shaped mold 12 is tilted and held in a V-shape when viewed from the side in the direction in which the resin droplets 15 are dropped. After the LD portion is completely covered with resin, the molded portion of the translucent resin 6 is formed by thermal curing or ultraviolet curing depending on the type of resin. According to this method, the portion of the transparent resin 6 that is not in contact with the L-shaped mold 12 becomes a free surface, but its shape does not affect the performance of the semiconductor laser device.

Similarly, in the semiconductor laser device having the structure shown in FIG. 2, it is possible to mold the transparent resin 6 by using the L-shaped mold 12. The bent portion of the frame 8a may be brought into contact with the inner wall surface 13 of the L-shaped mold 12, and the rest is basically the same as the method described above, so further description will be omitted. It can be seen from FIG. 3 that the semiconductor laser devices having the structures shown in FIGS. 1 and 2 can be resin-molded using molds of extremely simple shapes.

FIG. 4 shows a semiconductor laser device having the structure shown in FIG. 1, in which a parallel plate glass 16 with high transmittance and high plane accuracy is placed perpendicularly to the laser emission direction on the L of the lead frame 8.
It is a schematic diagram when it is pasted on the end face on the D chip 1 side. In this way, the soft light-transmitting resin 6 is not exposed on the outermost laser emission surface, and the surface is protected by the parallel flat glass 16, so it is possible to prevent the light-transmitting resin 6 from being damaged. Not only can the precision of surface smoothness itself be improved, but also the precision can be easily maintained. Furthermore, when molding the translucent resin 6, there is no need to use an L-shaped mold 12 as shown in FIG. 3, which has the great advantage of greatly simplifying the molding process of the translucent resin 6 .

FIG. 5 shows a schematic diagram of a three-beam compact disk semiconductor laser device as a modification of FIG. 4. In FIG. In FIG. 5, a diffraction grating 17 for dividing the laser beam into three beams is attached to the outermost end surface of the bent portion of the lead frame 8b, and a parallel flat plate glass 16a is attached to the other end surface of the bent portion, and the LD is a parallel flat plate. The lead frame 8b is not located between the glass 16a and the diffraction grating 17, but is located near the parallel flat glass 16a on the opposite side of the diffraction grating 17 and is not bent.
located on the main plane of This semiconductor laser device also does not require a mold for the transparent resin 6, as in the case of FIG. However, since the area around the LD is not restrained,
Depending on the case, it may be necessary to take measures to prevent excess resin from flowing out around the LD, such as adjusting the viscosity of the resin droplets to a higher level or placing a pad on the side of the LD. This semiconductor laser device utilizes the basic configuration of the present invention in which a part of the lead frame has a bent portion,
The portions to which the parallel flat glass 16a and the diffraction grating 17 are attached can be easily made in advance on the lead frame 8b, making it possible to obtain a versatile semiconductor laser device.

FIG. 6 shows a schematic diagram of a semiconductor laser device as a modification of FIG. 2, in which other optical elements are added. In FIG. 6, an opening 18 is formed by cutting out the vicinity of the center of the bent portion of the lead frame 8c, and a diffraction grating 17a is attached to the end face of the opening 18, and further extends from the opening 18 of the lead frame 8c in the light emission direction. A light exit hole 11a is formed in a portion where the tip of the extension is bent vertically at an angle of 45 degrees with respect to the light output direction, and a parallel plate beam splitter 19 is attached to the bent portion of the tip. At this time, the optical axis of the beam-split laser light is in the same plane as a plane parallel to the main surface of lead frame 8c. This semiconductor laser device can also be molded with the transparent resin 6 without a mold.

Since the parallel plate beam splitter 19 attached to the bent portion at the tip of the lead frame 8c needs to be tilted at 45° with respect to the laser beam emission direction, the tip of the lead frame 8c can be bent in two directions. Figure 6
In addition, the tip of the lead frame 8c is bent so that the optical axis of the beam-split laser beam is in the same plane as a plane perpendicular to the main surface of the lead frame 8c.
A schematic diagram of a semiconductor laser device in which a parallel plate beam splitter 19 is attached is shown in FIG. The other device configurations are exactly the same as in the case of FIG. 6.

As described above, by using the semiconductor laser device of the present invention by bending the lead frame, the mold resin can be held in the recess formed there and the positioning accuracy can be improved. It is also simple and does not require a sophisticated resin casting machine, resulting in great economical effects.

[0021]

[Effects of the Invention] Conventionally, resin mold type semiconductor laser devices were very unstable because the reference for positioning the light source on the device side was based on the shape of the mold resin. As mentioned in the example, a bent part is formed on the lead frame in a direction parallel or perpendicular to the laser beam emission direction, and this bent part is used as a reference for positioning. In other words, the lead frame itself is used as a reference for positioning the light source. Therefore, positioning accuracy can be greatly improved regardless of the resin used to mold the LD. In addition, high transmittance glass is attached to the end face of the recess formed by bending the lead frame.
It is possible to increase the smoothness of the laser beam emitting surface and also prevent the mold resin from being damaged. Resin molding can be done with a simple mold or without a mold, so the resin molding process is extremely simplified. moreover,
According to the present invention, since combinations with other optical elements are easily possible, a versatile semiconductor laser device can be obtained.

[Brief explanation of the drawing]

[Fig. 1] Schematic diagram of a semiconductor laser device of the present invention with a bent lead frame

[Figure 2] Schematic diagram of a semiconductor laser device with a lead frame bent in a different direction from Figure 1.

[Figure 3] Schematic diagram showing the mold state to explain the resin molding method

[Fig. 4] Schematic diagram of the semiconductor laser device of the present invention equipped with high transmittance glass

[Fig. 5] Schematic diagram of a semiconductor laser device of the present invention equipped with high transmittance glass and a diffraction grating.

[Fig. 6] Schematic diagram of a semiconductor laser device of the present invention equipped with a diffraction grating and a beam splitter.

[Figure 7] Schematic diagram of a semiconductor laser device with a lead frame bent at a different angle from Figure 6.

[Figure 8] Schematic diagram of a conventional resin mold type semiconductor laser device

[Explanation of symbols]

1 LD chip 1a Light exit surface 2 Submount 3 Photodiode 4a Lead frame 4b Lead frame 4c lead frame 5 Lead wire 6 Translucent resin 6a　Circular end face 7. Flange-shaped part 8 Lead frame 8a Lead frame 8b Lead frame 8c lead frame 9 Electrode 10 Insulating layer 11 Light exit hole 12 L-shaped mold 13 Inner wall surface 14 Resin liquid reservoir 15 Resin droplets 16 Parallel flat glass 16a Parallel flat glass 17 Diffraction grating 17a Diffraction grating

Claims (7)

[Claims] 1. A semiconductor laser device in which a laser diode element mounted on the main plane of a lead frame and a lead wire connected to the laser diode element are molded with a transparent resin, wherein the laser beam of the lead frame a recessed portion of the lead frame formed by partially bending both end portions parallel to the emission direction inward from both sides to a predetermined height;
A semiconductor laser device comprising the laser diode element provided on the bottom surface of the recess and the light-transmitting resin in which the lead wire is molded within the recess. 2. A semiconductor laser device in which a laser diode element mounted on the main plane of a lead frame and a lead wire connected to the laser diode element are molded with a transparent resin, the laser in the laser diode element A bent part in a direction perpendicular to the laser beam emission direction is formed by partially bending the tip of the lead frame on the chip side to a predetermined height toward the chip, and a hole is made in the center of this bent part, and the laser chip a laser beam emission hole or slit corresponding to the laser diode element, and the transparent resin in which the laser diode element and the lead wire are molded together with the laser beam emission hole or slit on the main plane of the lead frame where the laser diode element is located. A semiconductor laser device comprising: 3. A semiconductor laser device according to claim 1, further comprising a parallel plate glass attached to a tip end surface of said lead frame recess on a laser beam emission side. 4. A semiconductor laser device in which a laser diode element mounted on the main plane of a lead frame and a lead wire connected to the laser diode element are molded with a transparent resin, wherein the lead frame is attached to the laser diode element. A recess of the lead frame formed by partially bending both end portions parallel to the laser beam emitting direction inward to a predetermined height in an area extending from the installation location in the laser beam emitting direction, and a laser beam emitting portion of the recess. A semiconductor laser device characterized by having mutually different optical elements attached to both end faces in a direction and a perpendicular direction. 5. The semiconductor laser device according to claim 4, wherein the different optical elements are parallel flat glass and a diffraction grating. 6. A semiconductor laser device in which a laser diode element mounted on the main plane of a lead frame and a lead wire connected to the laser diode element are molded with a transparent resin, wherein the lead frame is attached to the laser diode element. A plurality of bent portions each having a predetermined height are formed at a predetermined distance in a direction perpendicular to the laser beam emitting direction in an area extending from the installation location in the laser beam emitting direction, and one of the bent portions is located at the leading edge of the bent portions, and is formed at a predetermined distance in a direction perpendicular to the laser beam emitting direction. 45 for the emission direction
What is claimed is: 1. A semiconductor laser device comprising: a bent portion having an inclined surface of .degree., a laser beam exit hole formed in the inclined surface, and a beam splitter attached to the laser diode element side of the inclined surface. 7. The semiconductor laser device according to claim 5, wherein the bent portion located at the leading edge has an inclined surface at an angle of 45° with respect to a direction perpendicular to the laser beam emission direction.