JPS59119774A - Photo coupling semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a photo coupling device of a small size and high moisture and insulation property by a method wherein a recess form reflection part is formed at the end surface of the first lead, an LED is contained therein, a photo transistor pellet is mounted at the flat part at the end surface of the second lead, which are arranged in opposition, and sealed with a transparent or opaque epoxy regin. CONSTITUTION:In the lead frame 34, the LED pellet 51 is installed and connected 52 at the flat part provided on the lead 31. In the lead frame 43, the LED pellet is contained in the reflection part 44 provided on the lead 41, and then connected 52. The tips of the leads 31 and 41 are opposed to each other at fixed distances and fixed to a metal mold, and the tip of each lead is sealed with the transparent epoxy resin 54, and further the molding for a package is performed by means of the black opaque epoxy resin 55. Thereafter, the device is completed by cutting the lead frame and dipping the shaped lead in solder. This constitution enables to obtain high insulation stregnth and high moisture resistance and to obtain a small-sized photo coupling device.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an optically coupled semiconductor device called a photocoupler in which a light emitting element and a light receiving element are housed in the same container.

[Technical background of the invention and its problems]

Conventionally, optically coupled semiconductor devices, so-called photocouplers, have been constructed as follows: first, an integrated elongated metal strip; and second, as shown in FIG. The lead frame 3 on the side is formed by a process such as punching, and the lead frame on the light receiving side is formed similarly (two elongated metal strips υ as shown in FIG. A wide part 4 is provided at the tip of one lead l of the light emitting side board frame 3, and a light emitting diode pellet is placed on this wide part 4 in a subsequent process. In addition, the other glue 2 of the light-emitting side lead frame 1 serves as one electrode lead on the light-emitting side, and in the subsequent process, gold (Au) is bonded between it and the electrode on the surface of the light-emitting diode pellet. ) A wide part 15 is also provided at the tip of the guide 11 located at the center of the light-receiving side lead frame 14. A phototransistor pellet is placed in the process of .In addition, the two leads 12 located on both sides of the light-receiving lead frame 14 are placed.
Reference numeral 13 indicates leads for, for example, base and emitter electrodes on the light-receiving side, and in a subsequent step, thin wires are bonded between the base and emitter electrodes on the surface of the phototransistor pellet. The pair of lead frames 3 and 14 are each bent into a predetermined shape before mounting the light emitting diode pellet and the phototransistor pellet and bonding with a thin wire.
After the device is placed and bonded, the light emitting diode pellet and the phototransistor pellet are placed so that they face each other (double overlapped).Then, as shown in the cross-sectional view of FIG. 3, the light emitting diode pellet 5 and A transparent liquid epoxy resin 21 is injected and cured to form an optical path between the phototransistor pellet 16 and the outer container is formed by molding with an opaque epoxy resin 22. It is completed by cutting the frame, forming, and soldering the leads.

By the way, the dielectric strength voltage between the light emitting side and the light receiving side is one of the important characteristics of a photocoupler, and the dielectric strength voltage depends on the distance between the light emitting diode pellet and the phototransistor pellet. However, in the conventional photocoupler having the above structure, the lead frames 3 and 14 are made from flat metal strips, and the lead frames are bent to make the light emitting diode pellet 5 and the phototransistor pellet 16 face each other. Therefore, the distance between them is only about 2u at most.

For this reason, there is a limit to the ability to provide a high dielectric strength voltage. Furthermore, if the lead height difference during bending is increased in order to make the distance 2u or more, the external shape of the epoxy resin 22 for the external container becomes correspondingly large, resulting in an increase in the size of the device.

Furthermore, even if the device is enlarged and the distance between the light emitting diode pellet 5 and the phototransistor pellet 16 is set to 2 or more, conventionally the surface on which the light emitting diode pellet 5 is placed is flat. Therefore, the light emitted from the light emitting diode pellet 5 does not sufficiently reach the surface of the phototransistor pellet 16, and the phototransistor pellet 16 no longer functions as a photocoupler.

Moreover, in the conventional photocoupler, the wide parts 4, 15 of the lead 1.11 on which the light emitting diode 5 and the phototransistor 16 are placed overlap each other, and the space between these overlapping parts is extremely small. When forming the passage, molding cannot be performed, so a liquid epoxy resin 21 with low viscosity is injected.

However, due to its low viscosity, this resin 21 is used in leads 1 and 1.
1 and flows outward. Since a gap is created between the flowed and hardened resin 21 and the leads 1 and 12, moisture easily enters from the outside, resulting in a decrease in moisture resistance.

OBJECT OF THE INVENTION The present invention has been made in consideration of the above-mentioned circumstances, and its purpose is to provide a small-sized optically coupled semiconductor device that can obtain high insulation resistance and high moisture resistance. There is a particular thing.

[Summary of the invention]

In order to achieve the above object, the present invention provides a concave reflective portion on the end face of the tip end of the first lead, a light emitting diode pellet is disposed within the reflective portion, and a light emitting diode pellet is disposed on the end face of the tip end of the second lead. A phototransistor pellet is provided on the flat part in a square shape, and the phototransistor pellet is placed on the second glue so that its tip faces the tip of the first lead. The first . An optically coupled semiconductor device is provided in which the tip of the second lead is molded with a transparent epoxy resin, and the turn of this resin is further molded with an opaque epoxy resin.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. An optically coupled semiconductor device, so-called a photocoupler, according to an embodiment of the present invention is constructed as follows. That is, first, as shown in FIG.
A lead frame groove 4 on the light receiving side having an angle of 32° 33 is formed by a process such as punching. Each lead 31 above.
32.33 is pressed, and the end surface of the lead 31 located at the center has a length approximately twice the thickness of the lead 31, that is, 1.0 to 1.0 mm, as shown in FIG. 2
A substantially square flat portion 35 having one side of the square is formed. Further, each lead 32, . 93, there is a square flat part 36 with a side length of 0.5 u as shown in FIG.
is formed. Thereafter, a phototransistor pellet is placed on the flat part 35 formed at the tip of the lead 31, and the remaining leads 32 and 33 serve as, for example, pace and emitter electrode leads on the light receiving side. In a subsequent step, the space between each of the paste and emitter electrodes on the surface of the phototransistor pellet and the flat portion 35 is bonded with a thin wire made of gold or the like.

Further, a lead frame 43 on the light emitting side having two leads 41 and 42 each is formed as shown in FIG. 7 by using metal strips similar to those described above. The end faces of the tip ends of the picture leads 41 and 42 are also pressed, and a concave reflective part 44 with an outer diameter of about 1 turn is formed on the end face of the lead 41, as shown in the perspective view of FIG. A flat portion 36 similar to that shown in FIG. 6 is formed on the end face of the other lead 42.

Thereafter, a light emitting diode pellet is placed in the reflective part 44 formed at the tip of one of the leads 4, and the other lead 42 is used as one electrode lead on the light emitting side, for example, an anode lead. Then, in a subsequent step, bonding is performed between the anode electrode on the surface of the light emitting diode pellet and its flat portion 35.

After forming the pair of lead frames 34 and 43 in this way, as shown in FIG. Bonding is performed using the thin wire 52. Similarly, on the lead frame 43 side, a light emitting diode pellet 53 is placed inside the reflective part 44 formed on the lead 41, and bonding is performed using the thin wire 52. After this, the lead 31 and A pair of lead frames 34 and 43 are fixed to a molding die so that the leading ends of the lead frames 41 face each other and are kept at a predetermined distance. After that, the leads 31, 32.3 are sealed so that the phototransistor pellet 51 and the light emitting diode pellet 53 are sealed.
3, 41. The tip of 42 is first coated with transparent epoxy resin 54.
Figure 0: Molding is performed as shown in Figure 2, and unnecessary parts of the lead frame 34 and 43, such as the door lever, are cut off. Furthermore, molding for the outer container is performed using opaque black epoxy resin 55, and then the lead frame is cut, formed, and the leads are soldered and dipped to form a 5-bin structure as shown in the perspective view of FIG. The photocoupler is completed.

In a photocoupler with such a configuration, the leads 31 and 41 are smaller than the conventional one in which the leads are bent and stacked on top of each other, and a light emitting diode pellet and a phototransistor pellet are placed facing each other inside the lead. Since the light emitting diode pellet and the phototransistor pellet are placed on the end face of the tip and are arranged to face each other, a sufficient distance can be maintained between the two pellets, and the degree of freedom is high. Moreover, since the thickness of the transparent epoxy resin 54 formed by the first molding can be kept constant without depending on this distance, the shape of the device can be made compact even if high insulation is achieved.

Furthermore, in order to achieve high insulation, even if the distance between both pellets is made relatively large, the light emitted from the pellet 53 is collected by the reflective portion 44 formed on the side of the light emitting diode pellet 53. Since the light reaches the surface of the phototransistor pellet 5 and the light distribution efficiency is greatly improved compared to the conventional method, it functions as a photocoupler even if the distance between both pellets is sufficiently large.

Furthermore, although the leading end of the lead frame is bent in the conventional manner, the portion corresponding to the optical path can be formed by molding. At this time, since an epoxy resin with a higher viscosity than a liquid is used, only a small amount flows out through the leads 31 and 47 to the outside, and during molding, even the thin bonding wire 52 is removed. Since it can be molded, the flowing and hardened resin can be removed without applying stress to the thin wire 52, thereby preventing the generation of gaps and improving moisture resistance by several times compared to the conventional method.

Note that this invention is not limited to the above-mentioned embodiment, and various modifications are possible. For example, in the above embodiment, a photocoupler with 5 pins in total, 2 pins on the light emitting side and 3 pins on the light receiving side, was described, but as shown in FIG. Then, another lead 45 without wiring may be provided (as well, the lead arrangement as shown in the top view of FIG. 13 may constitute a symmetrical 6-pin photocoupler.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to provide a small-sized optically coupled semiconductor device that can obtain high dielectric strength voltage and high moisture resistance.

[Brief explanation of drawings]

Figures 1 to 3 are for explaining conventional photocouplers, respectively. Figures 1 and 2 are plan views showing the lead frame, Figure 3 is a sectional view of the photocoupler 2, and Figures 4 to 3 are for explaining conventional photocouplers. FIG. 11 is for explaining a photocoupler according to an embodiment of the present invention, FIGS. 4 and 7 are plan views showing lead frames, and FIGS. 5 and 6 are end faces of lead tips. FIG. 8 is a plan view showing the shape of the lead tip, FIG. 8 is a perspective view showing the shape of the end face of the lead tip, and FIG.
The figure is a plan view showing the state when the lead frame is fixed to the mold, FIG. 10 is a plan view showing the state of molding with transparent resin, FIG. 11 is a perspective view of the entire completed photocoupler, and FIGS. 13 shows other embodiments of the present invention, FIG. 12 is a plan view showing a lead frame, and FIG. 13 is a top view of the entire photocoupler. 31.32, 33, 41, 42.45... Lead 1.
94, 4J frame, 36.36...
Flat part, 44... Reflective part, 51 Phototransistor pellet, 52... Thin wire, 53... Light emitting diode pellet, 54... Transparent epoxy resin, 55... Opaque epoxy resin. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 3 Figure 5 F7! J @ Figure 6 Figure 2 Figure 4 Figure 7 Figure 8 Figure 10 Figure @ 12 Figure 9 Figure 1 1 Figure 11 5 Figure 13

Claims (2)

[Claims] (1) A first lead having a concave reflective surface on the end face of the distal end, and a distal end of the first lead (2) The distal end of the first lead is arranged such that the distal ends thereof face each other, and a substantially square-shaped flat surface is formed on the end face of the distal end. a second lead having a surface, a light emitting element disposed within the reflective surface of the first lead, a light receiving element disposed on the flat surface of the second lead; A third lead is arranged along the lead and has a tip end electrically connected to the electrode on the light emitting element via a thin metal wire, and a third lead is arranged along the second lead and has a tip end made of metal. fourth and fifth leads electrically coupled to each of the electrodes on the light-receiving element via thin wires; and tips of the first to fifth leads so as to seal the light-emitting element and the light-receiving element. What is claimed is: 1. An optically coupled semiconductor device comprising: a light-transmissive resin member provided on the light-transmitting resin member; and a light-impermeable resin member provided to seal the light-transmissive resin member. (2) Above 1. The optically coupled semiconductor device according to claim 1, further comprising a sixth lead arranged along the third lead.