JPH0464193B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention comprises a light emitting element section that converts an electrical signal into an optical signal, and a photovoltaic element section having an amorphous semiconductor structure that converts the optical signal into an electrical signal. This invention relates to an optical coupling device.

[Conventional technology]

Conventionally, an optical coupling device consisting of a light emitting element section that converts an electrical signal into an optical signal and a photovoltaic element section having an amorphous semiconductor structure that converts the optical signal into an electrical signal is configured as shown in FIG. .

In the figure, 1 is a transparent substrate such as glass, 2
3 is an amorphous semiconductor layer such as amorphous silicon formed on the lower surface of the transparent conductive film 2; 4 is an amorphous semiconductor layer formed on the lower surface of the semiconductor layer 3; The transparent conductive film 2, the semiconductor layer 3, and the conductive electrode 4 constitute a light-emitting element section 5. The light-emitting element section 5 converts an electrical signal input via the connection line 6 into an optical signal. is converted to

7 is a transparent conductive film formed on the other main surface (upper surface) of the substrate 1, 8 is an amorphous semiconductor layer of a P-I-N structure such as amorphous silicon formed on the upper surface of the transparent conductive film 7, and 9 is a semiconductor. This is a conductive electrode formed on the upper surface of the layer 8, and the transparent conductive film 7, the semiconductor layer 8, and the conductive electrode 9 constitute a photovoltaic element section 10.

The optical signal from the light emitting element section 5 via the substrate 1 indicated by the solid arrow in FIG. 1 is transmitted to the photovoltaic element section 10.
is converted into an electrical signal by connecting wire 1.
1 to the outside.

[Problem that the invention seeks to solve]

In the case of the conventional device, since the electrical signal output from the photovoltaic element section 10 is weak, this electrical signal cannot be used as it is, and it is necessary to provide some kind of signal amplification means separately from the device.
There are problems with its lack of practicality.

The present invention has been made with the above points in mind, and an object of the present invention is to provide a novel and practical optical coupling device.

[Means to solve the problem]

In order to achieve the above object, the optical coupling device of the present invention includes a light emitting element portion 16 formed on one main surface of the transparent substrate 12 and a transparent conductive film formed on the other main surface of the substrate 12. A field effect transistor section 27 made of an amorphous semiconductor with 18 as a gate electrode, and a pin junction parallel to the film surface interposed between the transparent conductive film 18 and the gate insulating film 23 of the field effect transistor section 27. A photovoltaic element portion 22 made of an amorphous semiconductor is formed.

[Effect]

In the optical coupling device of the present invention configured as described above, an optical signal from the light emitting element section 16 is received by the photovoltaic element section 22 via the substrate 12, and is converted into an electrical signal by this element section 22. .

Further, this electric signal is amplified by a field effect transistor section 27 provided on the photovoltaic element section 22 and outputted to the outside of the apparatus.

〔Example〕

One embodiment will be described with reference to FIGS. 2 and 3.

In FIG. 2, 12 is a transparent substrate such as glass, 13 is a transparent conductive film formed on one main surface (lower surface) of the substrate 12, and 14 is amorphous silicon formed on the lower surface of the transparent conductive film 13. The amorphous semiconductor layer 15 is a conductive electrode formed on the lower surface of the semiconductor layer 14, and the transparent conductive film 13, the semiconductor layer 14, and the conductive electrode 15 constitute a light emitting element section 16.

The light emitting element section 16 formed on the lower side of the substrate 12 converts an electrical signal input from the outside via the connection line 17 into an optical signal, and this optical signal is emitted upward.

18 is a transparent conductive film such as tin oxide or indium oxide formed on the other main surface (upper surface) of the substrate 12;
19, 20, and 21 are P of amorphous silicon, etc., which are sequentially laminated on the upper surface of the transparent conductive film 18.
These are amorphous semiconductor layers of type, I type, and N type (hereinafter referred to as P layer, I layer, and N layer, respectively), and P layer 1
9. Photovoltaic element part 2 by I layer 20 and N layer 21
2 are configured.

The photovoltaic element section 22 formed on the upper side of the substrate 12 converts the optical signal from the light emitting element section 16 through the substrate 12, indicated by the solid arrow in FIG. 2, into an electrical signal.

23 is a gate insulating film having an insulating thin film structure formed on the upper surface of the N layer 21, 24 and 25 are conductive electrodes formed on the upper surface of the gate insulating film 23, and 26 is the gate insulating film 23 and both conductive electrodes 24. .
27 (referred to as an FET section) is configured.

That is, the photovoltaic element section 22 having a pin junction parallel to the film surface is interposed between the transparent conductive film 18 and the gate insulating film 23 of the FET section 27.

The FET section 27 has a gate formed by the transparent conductive film 18 and conductive electrodes 24 and 2.
5 forms a source and a drain, the equivalent circuit diagram of which is shown in FIG.

In Figure 3, G is the gate, S is the source, and D
is the drain, and DC is the DC bias power supply for the gate G, which are omitted in FIG.

The optical signal from the light emitting element section 16 shown by the arrow line of the waveform in FIG. It is superimposed on the voltage and amplified appropriately.

Through this amplification, signal amplification using the FET is performed, and an output obtained by amplifying the electric signal is taken out from the source S and drain D of the FET section 27.

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below.

A light emitting element section 16 is formed on one principal surface of the transparent substrate 12, and a field effect transistor section 27 having an amorphous semiconductor structure having a transparent conductive film 18 as a gate electrode is formed on the other principal surface of the substrate 12. 18 and the gate insulating film 23 of the field effect transistor section 27
Since the photovoltaic element part 22 having an amorphous semiconductor structure is inserted between the photovoltaic element part 22 and the photovoltaic element part 22, the electric signal of the photovoltaic element part 22 that converts the optical signal of the light emitting element part 16 is amplified by the field effect transistor part 27 and is transmitted outside the device. It is possible to easily provide a highly practical optical coupling device.

Further, since the field effect transistor section 27 is formed of an amorphous semiconductor, there is an advantage that the transistor section 27 can be easily manufactured and the device can be easily constructed three-dimensionally.

[Brief explanation of the drawing]

FIG. 1 is a front view of a conventional optical coupling device, FIG. 2 is a front view of one embodiment of the optical coupling device of the present invention, and FIG. 3 is an equivalent circuit diagram of FIG. 2. 12... Transparent substrate, 16... Light emitting element section, 1
8...Transparent conductive film, 22...Photovoltaic element portion, 2
3...Gate insulating film, 27...Field effect transistor section.

Claims (1)

[Scope of Claims] 1. An amorphous semiconductor having a light emitting element portion 16 formed on one main surface of a transparent substrate 12 and a transparent conductive film 18 formed on the other main surface of the substrate 12 as gate electrodes. A photovoltaic element made of an amorphous semiconductor having a pin junction parallel to the film surface interposed between the transparent conductive film 18 and the gate insulating film 23 of the field effect transistor part 27. An optical coupling device comprising: a portion 22;