JPS6328352B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical coupling device formed by directly attaching a chip-shaped light emitting element and a light receiving element to a substrate of a hybrid integrated circuit.

Production of film hybrid ICs that use film technology to form on insulating substrates to form passive elements such as resistors and conductors, and integrate active elements such as transistors and ICs or light emitting elements. Since the process is mainly based on printing technology, a circuit configuration with a two-dimensional expansion is adopted.

For example, as shown in FIG. 1, a resistor 1 and a conductor 2 are formed planarly on a substrate 3, a semiconductor chip 4 is die-bonded on the substrate 3, and is electrically connected to an electrode 6 using a very thin wire 5. It is connected. but,
Forming an optical coupling device by mounting a chip-like light emitting element and a light receiving element on such a substrate 3 requires that the light emitting surface of the light emitting element and the light receiving surface of the light receiving element face each other. It was difficult to realize this.
For this reason, conventionally, a method has been adopted in which the light emitting element 7 and the light receiving element 8 are housed as a pair facing each other in one package 9, and the board 3 is mounted on the completed part. In this way, the production process in which a light-emitting element and a light-receiving element are housed in one package, the parts are completed, and then mounted on a board is complicated, and it is difficult to integrate peripheral circuits. This led to high costs and made it difficult to miniaturize integrated circuits.

The present invention has been made in view of the above points, and includes a light emitting element and a light receiving element directly mounted on the same substrate, and the light emitting surface of the light emitting element and the light receiving surface of the light receiving element facing each other to optically connect the two. It is equipped with a light guide that connects to the By mounting the light-emitting element and the light-receiving element directly on the same substrate in this way, it is possible to simplify the production process such as wire bonding between these elements and electrodes, and also to mount the peripheral circuitry on the substrate immediately adjacent to the element. The present invention facilitates the miniaturization of hybrid integrated circuits by making it possible to form a light emitting element and a light receiving element, and further improves the accuracy of the optical coupling device by accurately determining the mutual positional relationship between the light emitting element and the light receiving element.

Hereinafter, embodiments of the present invention will be described based on the drawings from FIG. 2 onwards.

10 is a substrate made of glass, ceramic, etc., and this substrate 10 has a resistor 11 and a conductor 1.
The second prize was printed and formed into a chip.
A light emitting element 13 such as an LED and a light receiving element 14 such as a photodiode or phototransistor formed in a chip shape are directly die-bonded. These light-emitting element 13 and light-receiving element 14 are connected to electrodes 16 and 17 by ultrafine wires 15, and these electrodes 16 and 17 are connected to a peripheral circuit (not shown).

After the bonding, a light-shielding black resin layer 20 is molded to a constant thickness over the entire surface of the substrate 10, leaving only the circular holes 18 and 19 above the light-emitting element 13 and the light-receiving element 14. the circular hole 18,
When a transparent resin such as silicone resin or epoxy resin is injected into the lens 19 in an amount slightly larger than the volume of the small diameter portions 21 and 22, the first and second convex lenses 23 and 24 are formed due to surface tension. Ru. The first and second convex lenses 23 and 24 are connected to the light emitting element 1.
3 and the light receiving element 14.
A light shielding plate 25 for shielding light from the outside is provided on the upper part of the resin layer 20, and this light shielding plate 2
5 shows the light emitting surface of the light emitting element 13 and the light receiving element 1.
Holes 26 and 27 are formed above the light receiving surface of 4. One end of a light guide 28 made of plastic, glass, etc. and having a cylindrical shape or a bundle of fibers is inserted into one of the holes 26. One end of 28 is connected to the space 29 and the first
The light emitting surface of the light emitting element 13 is faced through the convex lens 23 . The other end of the light guide 28 is inserted into the other hole 27 of the light shielding plate 25 and faces the light receiving surface of the light receiving element 14 via the space 30 and the second convex lens 24. In this way, the light guide 28 is connected to the light emitting element 13.
The light emitting surface of the light receiving element 14 and the light receiving surface of the light receiving element 14 are optically coupled.

Next, the effect will be explained.

In FIG. 2, the light emitted from the light emitting element 13 spreads radially as shown by the arrows, is condensed by the first convex lens 23, becomes a light beam substantially parallel to its optical axis, and is transmitted through the space 29. light guide 2
The light is incident on one end of 8. This incident light passes through the light guide 28, exits from the other end, enters the second convex lens 24 via the space 30, is condensed here, and enters the light receiving surface of the light receiving element 14. In this way,
The light emitting element 13 and the light receiving element 14 are optically coupled.

In the above embodiment, the optical coupling device is formed with one light emitting element and one light receiving element, but as shown in FIGS. 3, 4 and 5, a plurality of light emitting elements 13 ₁ are formed. , 13 ₂ , 13 ₃ . . . and light receiving elements 14 ₁ , 14 ₂ , 14 ₃ . That is, the light emitting device 1 mounted on the substrate 10
_One end _{of the light guides 28 1 , 28 2 ,} 28 _{3 .}
The other end of 28 ₃ ... is provided on the light receiving surface of the corresponding light receiving element 14 ₁ , 14 ₂ , 14 ₃ .... In this way, the light emitting element 13 ₁ and the light receiving element 14 ₁ , 13 ₂ and the light receiving element 14 ₂ , 13 ₃ respectively form a pair.
and 14 ₃ ... are optically coupled.

In the present invention, as described above, a light emitting element and a light receiving element are mounted in chip form on the same substrate of a hybrid integrated circuit to form an optical coupling device. In addition to simplifying production processes such as bonding, it is possible to form a resistor, a conductor, or a peripheral circuit on a substrate immediately adjacent to a light emitting element or a light receiving element, thereby making it possible to miniaturize the hybrid integrated circuit.

Furthermore, although a plurality of pairs of light emitting elements and light receiving elements are provided to provide multi-channels, since optical cables are used as light guides, there is no interference or adverse effects between adjacent light paths. Furthermore, convex lenses are made by molding transparent synthetic resin onto the surfaces of the light-emitting element and light-receiving element, so they have a light-concentrating effect that prevents light from dispersing.
Furthermore, not only are these light emitting elements and light receiving elements sufficiently protected, but they can also be easily formed using the surface tension of the resin without the need for special convex lenses.

In addition, the holes through which light passes are made in one light-shielding plate, and each pair of light-emitting elements and light-receiving elements are mounted on one substrate, so the position and dimensions of the holes are accurate and more reliable optical coupling is achieved. It becomes possible.

[Brief explanation of drawings]

FIG. 1 is a side view showing a conventional example, and FIG. 2 is an enlarged sectional view showing an embodiment of the optical coupling device according to the present invention.
FIG. 3 is a front view of the optical coupling device according to the present invention formed in a multi-channel system, FIG. 4 is a plan view of the same, and FIG. 5 is a side view of the same. 3, 10...Substrate, 4...Semiconductor chip, 5,
15... extra fine wire, 6, 16, 17... electrode, 7,
13, 13 ₁ , 13 ₂ , 13 ₃ ... light emitting element, 8,
14, 14 ₁ , 14 ₂ , 14 ₃ ... light receiving element, 18,
19, 26, 27...hole, 20...resin layer, 2
3, 24... Convex lens, 25... Light shielding plate, 28,
28 ₁ , 28 ₂ , 28 ₃ ... light guide, 29,
30... Spatial section.

Claims (1)

[Claims] 1. In an optical coupling device in which a light emitting element and a light receiving element are directly mounted on the same substrate of a hybrid integrated circuit, and the light emitting element and the light receiving element are optically coupled by a light guide,
A plurality of pairs of light-emitting elements and light-receiving elements are mounted approximately in a straight line on the same substrate, and a transparent synthetic resin that also serves as protection is molded onto the surfaces of the light-emitting elements and light-receiving elements to form convex lenses. An optical coupling device characterized in that a light shielding plate is provided with a hole facing the convex lens of the light shielding plate, and a light guide made of an optical cable is inserted into a pair of holes of the light shielding plate.