JPS5858824B2 - Optical coupling semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optically coupled semiconductor device comprising a light emitting element and a light receiving element.

Recently, an optically coupled semiconductor device (photocoupler), which is a combination of a semiconductor light-emitting element and a semiconductor light-receiving element, has been attracting attention as a new solid-state element.

In a photocoupler, signal transmission is performed by light, and the input and output are electrically isolated, so it is suitable for signal transmission between parts with different potentials.

Furthermore, there is no feedback from the output side to the input side, and the directionality of signal transmission is excellent.

The structure of such a conventional photocoupler will be explained with reference to FIG.

In FIG. 1, 10 indicates the light emitting side and 20 indicates the light receiving side.

On the light emitting side 10, 11 is a semiconductor light emitting element, and one electrode 12 of the semiconductor light emitting element 11 is fixed onto a metal lead 13.

The other electrode 14 of the semiconductor light emitting device 11 is connected to the thin lead wire 1
5, it is electrically connected to another metal lead 16.

On the light receiving side 20, 21 is a semiconductor light receiving element, one electrode 22 of this semiconductor light receiving element 21 is fixed on a metal lead 23, and the other electrode 24 is connected to another metal lead 26 by a thin lead wire 25. electrically connected to.

Although omitted in FIG. 1, a transparent insulator with a high refractive index, such as epoxy resin or silicone resin, is usually placed between the semiconductor light emitting element 11 and the semiconductor light receiving element 21.
Efforts are made to increase the luminous flux reaching the semiconductor light receiving element 21 from the semiconductor light emitting element 11.

When a voltage is applied between the metal leads 13 and 16 on the light emitting side 10, light is generated within the semiconductor light emitting device 11.

These lights are emitted from the surface (principal surface 17) of the semiconductor light emitting device 11, and some of the light reaches the semiconductor light receiving device 21.

These lights are absorbed by the semiconductor light receiving element 21 and become electrical signals between the metal lead 23 on the light receiving side 20 and the metal lead 2.
Detected between 6 and 6.

However, the photocouplers having the conventional structure described above have the following drawbacks.

First, light generated within the semiconductor light emitting device 11 is emitted to the outside not only from the main surface 17 but also from both side surfaces 18 as shown by dotted lines. is not irradiated.

Further, not all of the light emitted from the principal surface 17 is irradiated onto the semiconductor light receiving element 21, but only a portion thereof is used for irradiation.

That is, the optical signal is not effectively transmitted from the light emitting side 10 to the light receiving side 20.

Furthermore, in a photocoupler with a conventional structure, the semiconductor light emitting device 1
1 (guibond, wire bond) and the gluing of the semiconductor light-receiving element 21 are performed independently, and then the two are integrated, which makes the gluing process complicated and the alignment of the two difficult.

The present invention has been made in consideration of the above-mentioned points, and provides an optically coupled semiconductor device that can effectively transmit optical signals from a semiconductor light emitting element to a semiconductor light receiving element and that has a simple assembly process.

This invention will be explained below.

Figures 2a and 2b show a first embodiment of the invention.

Figure 2a shows a plan view with the lid removed, and Figure 2a shows a sectional view.

In FIGS. 2a and 2b, 31 is an insulating substrate, and a recess 32 of a desired shape is formed in this insulating substrate 31. As shown in FIG.

A light reflecting member 34 is provided on each surface 33 of the side wall of the recess 32 .

and metal lead 13. 16, 23, and 26 are formed so as to penetrate through the insulating substrate 31 and have their heads located on the bottom surface of the recess 32.

In addition, the light emitting side 10 and the light receiving side 20 are formed in the same manner as in FIG.

Reference numeral 41 denotes a lid having a light reflecting member 43 provided on its lower surface 42, and this lid 41 is arranged so as to bridge the recess 32.

Next, the operation will be explained.

When a voltage is applied between the metal leads 13 and 16 on the light emitting side 10, light is generated within the semiconductor light emitting device 11.

These lights are transmitted to the main surface 17 and front side surface 1 of the semiconductor light emitting device 11.
8F, rear side 18B, left side 18L, and right side 18R.

Of these four surfaces, the light emitted from the front side surface 18F is directly directed to the semiconductor light receiving element 21, and the light emitted from the left and right side surfaces 18L and 18R is emitted from the light reflecting member 34 provided on the surface 33 of the side wall of the four parts 32. reflected to the semiconductor light receiving element 21,
The light emitted from the main surface 17 is reflected by a light reflecting member 43 provided on the lower surface 42 of the lid 41 and is irradiated onto the semiconductor light receiving element 21 .

The light irradiated onto the semiconductor light receiving element 21 is absorbed and converted into an electrical signal, which is detected between the metal lead 23 and the metal lead 26 on the light receiving side 20.

As described above, in the optically coupled semiconductor device according to the present invention, the main surface 17 and each side surface 18F, 18L,
The light emitted from 18R effectively reaches the semiconductor light receiving element 21, and the light transmission efficiency is high.

Furthermore, since the recess 32 is filled with a transparent insulating material such as epoxy resin or silicone resin (not shown), the refractive index matching allows the semiconductor light to be received from the semiconductor light emitting element 11 more effectively than when the recess is filled with air. Light is transmitted to element 21.

3a and 3b show a second embodiment of the optically coupled semiconductor device according to the present invention.

FIG. 3a is a plan view with the white lid 41' removed, and FIG. 3 is a sectional view.

Each reference numeral in FIG. 3 that is the same as that in FIG. 2 corresponds to that in FIG. 2, respectively.

Figure 3a. In b, 31' is a white insulating substrate,
A recess 32 is formed in this white insulating substrate 31', and a semiconductor light emitting element 11 and a semiconductor light receiving element 21 are arranged within this recess 32.

Since the insulating substrate 31' itself is white, the surface 33 of the side wall of the recess 32 has high light reflectivity.

In FIG. 3, the light emitted from the front side 18F is directly directed to the semiconductor light receiving element 21, and the light emitted from the left side 18L and right side 18R is reflected by the surface 33 of the side wall of the recess 32 and is directed to the semiconductor light receiving element 21. The light emitted from the main surface 17 is reflected by the light-reflecting lower surface 42 of the white lid 41' and is irradiated onto the semiconductor light-receiving element 21.

In this way, also in the optically coupled semiconductor device according to the present invention shown in FIG.
The light emitted from F, 18L, and 18R effectively reaches the semiconductor light receiving element 21, and the light transmission efficiency is high.

As in the case of FIG. 2, since the four parts 32 are filled with a transparent insulating material, such as epoxy resin or silicone resin, the semiconductor light emitting element 11 can be more effectively removed from the semiconductor light emitting element 11 by matching the refractive index. Light is transmitted to the semiconductor light receiving element 21.

FIG. 4 shows a third embodiment of the optically coupled semiconductor device according to the present invention, in which a plurality of recesses 32, three in this embodiment, are provided in an insulating substrate 31, and each recess 32 is shown in FIG. The optically coupled semiconductor device shown in FIG.

In this embodiment, a pair of each semiconductor light emitting element 11 and each semiconductor light receiving element 21 is arranged in one recess 32, and the lid 41 covers the opening of the recess 32. The optical signal emitted from the recess 32
The light is irradiated only to the semiconductor light-receiving element 21 inside, and the other recesses 32 are irradiated.
The light does not reach the semiconductor light-receiving element 21 inside, so malfunctions can be prevented.

In the above-described embodiment, one semiconductor light emitting element 11 and one semiconductor light receiving element 21 were arranged in the recess 32, but a plurality of semiconductor light emitting elements 11 and a plurality of semiconductor light receiving elements 2
1 may be arranged as one group.

Furthermore, even if the recess 32 is filled with a transparent insulating material other than epoxy resin or silicone resin having a high refractive index, light can be effectively transmitted from the semiconductor light emitting element 11 to the semiconductor light receiving element 21.

As the semiconductor light emitting device 11, in addition to a light emitting diode and an electroluminescent device, a semiconductor laser or the like may be arranged.

As described above in detail, in the optically coupled semiconductor device of the present invention, the semiconductor light emitting element and the semiconductor light receiving element can be arranged on the same plane, for example, on the bottom surface of the recess, so that the assembly process is significantly simplified.

In addition, since the recess is covered with a lid and the opening of the recess is filled with a transparent insulating material, not only the semiconductor light emitting element and the semiconductor light receiving element inside are firmly fixed, but also the semiconductor light receiving element is received from the semiconductor light emitting element. There are advantages such as being able to increase the efficiency of transmitting light to the element.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the structure of a conventional optically coupled semiconductor device, FIGS. Figure a,
b is a plan view and a cross-sectional view with the lid removed showing a second embodiment of the optically coupled semiconductor device according to the present invention, and FIG. 4 is a cross-sectional view showing a third embodiment of the optically coupled semiconductor device according to the present invention. be. In the figure, 10 is a light emitting side, 11 is a semiconductor light emitting element, 12.1
4 is an electrode, 13.16 is a metal lead, 15 is a thin lead wire, 17 is a main surface, 18F, 18L, 18R are side surfaces, 20 is a light receiving side, 21 is a semiconductor light receiving element, 22.24 is an electrode, 2
3.26 is a metal lead, 25 is a thin lead wire, 31 is an insulating substrate, 31' is a white insulating substrate, 32 is a recess, 33 is a side wall surface, 34 is a light reflecting member, 41 is a lid, 41' is a white insulating substrate The lid, 42 is a lower surface, and 43 is a light reflecting member. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A recess of a desired shape is formed in an insulating substrate, at least one semiconductor light emitting element and at least one semiconductor light receiving element are arranged in the recess, a lid is placed over the recess, and the inner surface of the recess and the inner surface of the lid are A light-coupled semiconductor device characterized in that a required portion of the recess is covered with a light reflecting member, and an opening of the recess is filled with a transparent insulating material.