JP3118353B2 - Optical semiconductor coupling device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small and thin optical semiconductor coupling device (hereinafter, referred to as a "photocoupler") for transmitting input and output by light.

[0002]

2. Description of the Related Art FIG.
This will be described with reference to FIG. Here, FIG. 3 is a sectional view showing a conventional photocoupler.

In a conventional photocoupler, as shown in FIG. 3, a light emitting element 1 and a light receiving element 2 are die-bonded to respective lead frames 8 and 9 with an Ag paste or the like, and wires are applied with an Au wire 3 or the like. 1 and 2 are arranged so as to be optically coupled to each other, and an optical path is formed between the light emitting element 1 and the light receiving element 2 by a light transmitting resin 6 such as a silicone resin. It is formed by molding.

Here, the distance a between the light emitting element 1 and the light receiving element 2
Is as thick as about 0.55 mm, and the guaranteed value of the withstand voltage at that time is as low as 3.8 Kv.

[0005]

As shown in FIG. 3, the conventional photocoupler is mounted on lead frames 8, 9 which are opposed to each other so that a light emitting element 1 and a light receiving element 2 are optically coupled. , Between the light emitting element 1 and the light receiving element 2,
An optical path was formed by a light-transmitting resin 6 such as a silicone resin having a stress relaxation property for both elements.

As a result, the withstand voltage between the light emitting element 1 and the light receiving element 2 is necessarily determined by the insulating ability of the light transmitting resin 6 and the distance between the light emitting element 1 and the light receiving element 2.
In order to obtain a certain withstand voltage, it is necessary to increase the distance between the light emitting element 1 and the light receiving element 2 which form an optical path.

Therefore, when the distance for forming the optical path is increased, the amount of the light-transmitting resin 6 increases. Therefore, when heat such as reflow when attaching the photocoupler to the substrate is applied, the thermal expansion coefficient of the light-transmitting resin 6 is reduced. Since the thermal expansion coefficient is larger than the thermal expansion coefficient of the insulating light-shielding resin 7, which is an exterior molding resin, an excessive expansion stress is applied to the insulating light-shielding resin 7, and as a result, cracks occur in the insulating light-shielding resin 7 and quality trouble occurs. Could be.

Further, as a market trend in recent years, high-density mounting has progressed, and there has been a demand for smaller and thinner photocouplers.

[0009] Therefore, in order to reduce the size and thickness,
In addition to the miniaturization of the device itself, an efficient packaging technique for the constituent materials around the device is required.

The present invention has been made in view of the above problems, and provides a photocoupler that does not cause cracks in an exterior molding resin due to heat of reflow or the like, and that is smaller and thinner than conventional products. Is what you do.

[0011]

In order to achieve the above object, in a photocoupler arranged so that a light emitting element and a light receiving element are optically coupled, a light transmitting portion in which the light emitting element and the light receiving element are arranged to face each other. And other light-shielding parts
An insulating sheet comprising: a first conductive pattern for die-bonding the light emitting element on one surface of the insulating sheet, and a second conductive pattern for die-bonding the light receiving element on the other surface; Both elements and the insulation sheet
The light transmitting portion covered by the light transmitting resin, these and the
At least a part of the light shielding portion of the insulating sheet is molded with an insulating light shielding resin.

Further, in the photocoupler according to the first aspect, the insulating sheet has a withstand voltage per unit thickness.
The insulating sheet is characterized by being an insulating sheet larger than the withstand voltage of the light transmitting resin.

Further, in the photocoupler according to the second aspect, the insulating sheet is made of a polyimide resin and has a thickness.
0.2 to 0.3 mm .

[0014]

According to the photocoupler of the present invention having the above-described structure, the amount of the light-transmitting resin covering the light-emitting element and the light-receiving element is small. Since no cracks are generated and the distance between the two elements is reduced, a small-sized photocoupler having a small thickness of the exterior molding resin can be provided. Further, the insulating sheet mainly comprises a light emitting element and a light receiving element.
Light-transmitting part where the elements are arranged facing each other, and other light-shielding parts
Light from outside through the insulating sheet
Photocoupler with excellent light transmission efficiency without intrusion
Can be provided.

Further, by selecting an insulating sheet having an excellent insulating ability, a withstand voltage sufficient for practical use as a photocoupler can be secured.

Further, polyimide is used as the material of the insulating sheet.
Use resin and make the thickness 0.2-0.3mm
As a result, the workability is excellent and sufficient insulation resistance can be secured.
You.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of one embodiment of the photocoupler of the present invention, and FIG. 2 is a cross-sectional view of another embodiment of the photocoupler of the present invention.

As shown in FIG. 1, on both surfaces of one insulating sheet 5, patterning is performed by a conductive pattern 4 on a place where the light emitting element 1 and the light receiving element 2 are mounted and a place where wire bonding is performed. It is.

One insulating sheet 5 is used for the light emitting element 1.
And a light transmitting portion 5a at the center of the sheet to which the light receiving element 2 is die-bonded, and light shielding portions 5b at both ends of the sheet.

Then, the light emitting element 1 and the light receiving element 2 are die-bonded at the positions patterned on both sides of the insulating sheet 5 with the conductive material.
And an Au wire 3 on a patterning portion different from the light receiving element 2.
Wire bond with.

Subsequently, the light emitting element 1 and the light receiving element 2 are coated with a light transmissive resin 6 such as a silicone resin having a stress relaxation property, and the exterior is molded with an insulating light shielding resin 7 such as an epoxy resin. Is bent into a substantially L-shape to produce the photocoupler of the present invention.

Here, a polyimide resin is used as the material of the insulating sheet 5, and the breakdown voltage of the polyimide resin is approximately 6.5 Kv for a thickness of 0.025 mm. 0.2-0.3m thick
By setting m, a withstand voltage of 3.8 Kv or more can be ensured.

With the above structure, the amount of the light-transmitting resin 6 covering the light-emitting element 1 and the light-receiving element 2 is small while maintaining a dielectric strength equal to or higher than that of the conventional photocoupler. Since there is no crack in the molding resin and the distance between the two elements is short, a small-sized photocoupler having a small thickness of the exterior molding resin can be provided.
In addition, since the opposing elements are close to each other and the insulating sheet 5 mainly includes the light transmitting portion 5a in which the light emitting element 1 and the light receiving element 2 are arranged to face each other, and the other light shielding portion 5b, the light transmission efficiency is excellent. A photocoupler can be provided.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that modifications and changes can be made to the embodiment within the scope of the present invention.

For example, when the light receiving element 2 has mechanical strength with respect to the insulating light-shielding resin 7 which is an exterior molding resin,
As shown in FIG. 2, a portion where the light receiving element 2 and the light transmitting portion 5 a of the insulating sheet 5 are close to each other may be covered with the light transmitting resin 6 at a minimum.

[0026]

As described above, according to the photocoupler of the present invention, the light emitting element and the light receiving element are arranged on the insulating sheet so as to face each other with the insulating sheet interposed therebetween. As a result, since the amount of the light-transmitting resin can be reduced, there is no occurrence of cracks in the exterior molding resin due to heat such as reflow when attaching the photocoupler to the substrate, and a small-sized photocoupler having a small exterior molding resin thickness. Can be provided. Furthermore, insulating sheets are mainly used
A light transmitting portion in which an optical element and a light receiving element are arranged facing each other;
The light shielding part other than
Excellent light transmission efficiency without light entering through the port
Photocouplers can be provided.

Further, by selecting an insulating sheet having an excellent insulating ability, a withstand voltage sufficient for practical use as a photocoupler can be secured.

Further, polyimide is used as the material of the insulating sheet.
Use resin and make the thickness 0.2-0.3mm
As a result, the workability is excellent and sufficient insulation resistance can be secured.
You.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a photocoupler of the present invention.

FIG. 2 is a sectional view showing another embodiment of the photocoupler of the present invention.

FIG. 3 is a cross-sectional view showing a conventional photocoupler.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light emitting element 2 Light receiving element 3 Au wire 4 Conductive pattern 5a Light transmitting part 5b Light shielding part 6 Light transmitting resin 7 Insulating light shielding resin 8 Light emitting element side lead frame 9 Light receiving element side lead frame

Claims (3)

(57) [Claims] 1. An optical semiconductor coupling device in which a light-emitting element and a light-receiving element are arranged to be optically coupled to each other.
An insulating sheet comprising an outer light-shielding portion, a first conductive pattern for die-bonding the light emitting element on one surface of the insulating sheet, and a second conductive pattern for die-bonding the light receiving element on the other surface. Having the two elements and the
An optical semiconductor coupling device, wherein a light transmitting portion of an insulating sheet is covered with a light transmitting resin, and at least a part of the light shielding portion of the insulating sheet is molded with an insulating light shielding resin. Wherein said insulating sheet is dielectric strength per unit thickness, the optical semiconductor coupling device according to claim 1, characterized in that a withstand voltage is larger than the insulating sheet of the light transmitting resin. Wherein said insulating sheet is a polyimide resin
The optical semiconductor coupling device according to claim 2 , wherein the thickness is 0.2 to 0.3 mm .