JPH0697487A - Photocoupler - Google Patents

Abstract

PURPOSE:To provide a photocoupler which is easy to make and which has a high photocoupling efficiency. CONSTITUTION:A light emitting diode 13 is provided on the surface of the light receiving side of a photodiode array 23 via a translucent insulating film 12. The light emitting element 13 comprises a translucent electrode 31 provided on a translucent insulating film 12, a light emitting polymer film 32 which is provided on this translucent electrode 31, and a metal electrode 33 provided on this light emitting polymer film 32 and serving as a light reflecting element.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photocoupler device having a light emitting element and a light receiving element.

[0002]

2. Description of the Related Art As is well known, a photocoupler device is widely used for transmitting and receiving a signal while ensuring electrical insulation.

By the way, the photocoupler device is usually constructed as shown in FIG. That is, the separately manufactured light emitting element 1 and light receiving element 2 are mounted on different stems 3 and 4, respectively, and the light emitting element 1 and the light receiving element 2 are made to face each other, and a transparent resin 5 is provided between both elements.
Are optically coupled with each other and are molded with an opaque resin 6.

However, the photocoupler device having the above-described structure has a problem that it requires a complicated manufacturing process and thus becomes expensive. Further, since the light emitted from the light emitting element 1 is easily dispersed, there is a problem that the amount of light incident on the light receiving element 2 is small and the optical coupling efficiency is low.

[0005]

As described above, in the conventional photocoupler device, there is a problem that the optical coupling efficiency is low as well as the cost is high because a complicated manufacturing process is required.

Therefore, an object of the present invention is to provide a photocoupler device capable of solving all of the above-mentioned problems.

[0007]

In order to achieve the above object, in a photocoupler device according to the present invention, a semiconductor light receiving element and a semiconductor light receiving element, which is provided on the surface of the semiconductor light receiving element via a light transmissive insulating film, is provided with an electric current. And a light-emitting element provided with a light-reflecting element that directs the light emitted to the semiconductor light-receiving element side of the light emitted from the light-emitting film to the semiconductor light-receiving element side. It has.

As the light emitting film, a light emitting polymer, porous silicon or silicon carbide which has been subjected to a light emitting treatment is used.

[0009]

Since the light emitting film is used as the light emitting body, the light emitting film can be directly attached to the surface of the semiconductor light receiving element through the translucent insulating film, and the same manufacturing process as the semiconductor manufacturing process can be performed. Can be adopted. Therefore, the price can be reduced. Further, the fact that the light emitting film is directly attached to the surface of the semiconductor light receiving element via the translucent insulating film and the provision of the light reflecting element can contribute to the improvement of the optical coupling efficiency.

[0010]

Embodiments will be described below with reference to the drawings.

FIG. 1 shows a photocoupler device according to a first embodiment of the present invention.

This photocoupler device comprises a semiconductor light receiving element 11 and a light emitting element 13 provided on the light receiving side surface of the semiconductor light receiving element 11 with a translucent insulating film 12 interposed therebetween.

In the case of this embodiment, the semiconductor light receiving element 11 has a photodiode array 23 in which a plurality of photodiodes 21 are separated by a dielectric 22 and arranged two-dimensionally, and these photodiodes 21 are connected in series. It is composed of.

The transparent insulating film 12 is made of a film of silicon dioxide or the like, and is formed on the surface of the photodiode array 23 by the CVD method or the like.

The light emitting element 13 is constructed as follows. That is, a transparent electrode 31 made of tin oxide or the like is provided on the surface of the transparent insulating film 12, and a light emitting polymer film 32 as a light emitting film is provided on the surface of the transparent electrode 31. The luminescent polymer film 32 is formed by dropping a solution of a luminescent polymer on the transparent electrode 31 and spin-coating the solution. Then, on the upper surface of the light emitting polymer film 32, a metal electrode 33 which also functions as a light reflecting member is formed. In forming the metal electrode 33, first, an excess region of the light emitting polymer film 32 is selectively removed, and then a contact hole is formed in the light transmissive insulating film 12 to obtain the output of the photodiode array 23, and thereafter, A method of forming a metal electrode on the entire surface and patterning the metal electrode is adopted.

In the figure, 34a and 34b indicate output terminals of the photodiode array 23, and 35a and 35b indicate drive terminals of the light emitting element 13.

This photocoupler device operates as follows. That is, when a voltage is applied between the terminals 35a and 35b, a current flows through the light emitting polymer film 32, and the light emitting polymer film 32 emits light. Of this emitted light,
The light emitted in the direction of the photodiode array 23 is
As it is, the light is transmitted through the transparent electrode 31 and the transparent insulating film 12, and the photodiode array 23 is irradiated with the light. Further, the light emitted toward the side opposite to the photodiode array 23 is reflected by the metal electrode 33 provided on the surface of the light emitting polymer film 32 and is irradiated toward the photodiode array 23.

When the photodiode array 23 is irradiated with light, a photoelectromotive force is generated in the PN junction portion of each photodiode 21, and this photoelectromotive force is output from between the terminals 34a and 34b. Function is demonstrated. In this case, the light emitting element 13 and the semiconductor light receiving element 11
The electrical insulation between the light emitting element 13 and the photodiode array 23 is ensured by the translucent insulating film 12.

As described above, since the light emitting polymer film 32 is used as the light emitting body, the light emitting polymer film 32 can be directly attached to the surface of the semiconductor light receiving element 11 via the light transmitting insulating film 12. . Therefore, it is possible to adopt a consistent manufacturing process similar to the semiconductor manufacturing process and eliminate the need for complicated assembly processes.
It can contribute to lower prices. Further, the light emitting polymer film 32 is directly attached to the surface of the semiconductor light receiving element 11 via the light transmitting insulating film 12, and the light reflecting function of the metal electrode 33 is combined, and the light emitting element 13 and the semiconductor light receiving element are combined. The optical coupling efficiency with 11 can be improved.

FIG. 2 shows a photocoupler device according to a second embodiment of the present invention.

In this figure, the same parts as in FIG. 1 are designated by the same reference numerals. Therefore, detailed description of the overlapping portions will be omitted.

The photocoupler device according to this embodiment is shown in FIG.
The difference from the one shown in FIG. 11 lies in the configuration of the light emitting element 13a. That is, in the light emitting element 13a, a plurality of unit light emitting elements 36 each including the translucent electrode 31a, the light emitting polymer film 32a, and the metal electrode 33a are arranged along the surface of the translucent insulating film 12, and these unit light emitting elements are arranged. 36 are connected in series.

With such a structure, the same effects as those of the above-described embodiment can be expected, and the following effects can be obtained. That is, since the light emitting element 13a is formed in the divided structure, the area of the light emitting polymer film 32a in each unit light emitting element 36 can be reduced. Therefore, unlike the case where a current is applied to a large area of a light-emitting polymer film with a pair of electrodes, there is no risk of an in-plane distribution of the emission intensity due to the imbalance of the current, and the in-plane uniformity is achieved. It is possible to obtain a high emission intensity.

FIG. 3 shows a photocoupler device according to a third embodiment of the present invention.

In this figure, the same parts as those in FIG. 1 are designated by the same reference numerals. Therefore, detailed description of the overlapping portions will be omitted.

The photocoupler device according to this embodiment is shown in FIG.
The difference from what is shown in FIG. 2 is the configuration of the light emitting element 13b. That is, the light emitting element 13 b is a low-resistance metal electrode 37 formed in a comb shape on the upper surface of the translucent insulating film 12.
And the light emitting polymer film 32b is arranged so as to cover the metal electrode 37, and the metal electrode 33 having a light reflecting function is arranged on the upper surface of the light emitting polymer film 32b.

With such a structure, the same effects as those shown in FIG. 1 can be obtained, and the following effects can be obtained. That is, when the electrode located on the side of the translucent insulating film 12 is composed of a translucent electrode, it is necessary to reduce its thickness in order to increase the light transmittance. Therefore, the electric resistance becomes large, and the loss at this electrode becomes large.
However, when the electrode located on the transparent insulating film 12 side is formed of the comb-shaped low resistance metal electrode 37 as in this embodiment, the loss is suppressed without impairing the light transmittance. You can

FIG. 4 shows a photocoupler device according to a fourth embodiment of the present invention.

In this figure, the same parts as those in FIG. 3 are designated by the same reference numerals. Therefore, detailed description of the overlapping portions will be omitted.

The photocoupler device according to this embodiment is shown in FIG.
What is different from that shown in FIG. 6 is the configuration of the light emitting element 13c. That is, the light emitting element 13c includes the low resistance metal electrodes 37a, 37 formed in a comb shape on the upper surface of the translucent insulating film 12.
b is arranged such that its teeth are engaged with each other with a predetermined distance therebetween, and a light emitting polymer film 32b is arranged so as to cover these metal electrodes 37a and 37b, and a light reflecting function is provided on the upper surface of the light emitting polymer film 32b. The metal electrode 33 provided with is arranged. The one metal electrode 37b is connected to the metal electrode 33.

With such a structure, the light emitting element 13c
Is driven, a potential difference is generated between the adjacent teeth of the metal electrodes 37a and 37b arranged so that their teeth mesh with each other. Therefore, when driven, the luminescent polymer film 3
The current flowing through 2b flows through two systems, that is, the route between the metal electrode 33 and the metal electrode 37a and the route between the metal electrode 37a and the metal electrode 37b. For this reason,
The amount of decrease in the amount of light blocked by the presence of the metal electrodes 37a and 37b can be compensated by the emitted light due to the current flowing through the route between the metal electrode 37a and the metal electrode 37b. Therefore, it is possible to prevent a decrease in the amount of irradiation light that tends to occur when the electrode located on the transparent insulating film 12 side is formed of a metal electrode, and it is possible to effectively irradiate the photodiode array 23 with light.

FIG. 5 shows a photocoupler device according to a fifth embodiment of the present invention.

In this figure, the same parts as in FIG. 1 are designated by the same reference numerals. Therefore, detailed description of the overlapping portions will be omitted.

The photocoupler device according to this embodiment is shown in FIG.
What is different from that shown in FIG. 6 is the configuration of the light emitting element 13d. That is, the light emitting element 13d has a comb shape or a dot shape so that the light emitting polymer film 32 is divided into a plurality of parts in the direction along the film surface of the translucent insulating film 12 and a potential difference is generated between the adjacent parts during driving. The electrodes 38 and 39 in the shape of a circle are provided, and a light reflection film 41 is formed on the upper surface of these electrodes with a translucent insulating film 40 interposed therebetween.

Even with this structure, the same effects as those of the above-described embodiments can be expected. In this embodiment, the light reflection film 4
When 1 is an insulating material, the translucent insulating film 40 can be omitted. Further, as the light reflection film 41, a substance having a refractive index higher than that of the light emitting polymer film 32 may be used.

The present invention is not limited to the above embodiment. That is, in each of the above-described embodiments, the semiconductor light receiving element 11 is composed of the photodiode array 23, but any element such as a phototransistor or a photothyristor whose electric characteristics change in response to light may be used. Further, in each of the above-described embodiments, the light emitting polymer film is used as the light emitting film, but the light emitting film may be formed of porous silicon or silicon carbide which has been made light emitting.

[0037]

As described above, according to the present invention, the optical coupling efficiency can be improved without any complicated process, and the optical coupling efficiency can be improved without impairing the original function.

[Brief description of drawings]

FIG. 1 is a sectional view of a photocoupler device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a photocoupler device according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a photocoupler device according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a photocoupler device according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a photocoupler device according to a fifth embodiment of the present invention.

FIG. 6 is a sectional view of a conventional photocoupler device.

[Explanation of symbols]

11 ... Semiconductor light receiving element 12 ... Translucent insulating film 13, 13a, 13b, 13c, 13d ... Light emitting element 23 ... Photodiode array 31, 31a ... Translucent electrode 32, 32a ... Luminescent polymer film 33, 37, 37a , 37b, 38, 39 ... Metal electrode 41 ... Light reflection film

Claims (2)

[Claims] 1. A semiconductor light-receiving element, a light-emitting film provided on the surface of the semiconductor light-receiving element via a light-transmissive insulating film, and emitting light upon energization, and the light emitted from the light-emitting film. A photocoupler device comprising: a light emitting element having a light reflecting element for directing light emitted to the semiconductor light receiving element side to the semiconductor light receiving element side. 2. The light emitting film is formed of one kind selected from a light emitting polymer, light-emergent treated porous silicon and SiC.
The photocoupler device according to 1.