JPH0349403Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a photocoupler in which a light emitting element and a light receiving element are optically coupled and integrated.

<Summary of the invention> In order to improve the dielectric strength of a photocoupler, the present invention mounts a light emitting element and a light receiving element in parallel on a lead frame in one plane, and a concave surface is formed downward on the bottom side of the lead frame. The structure is such that a heat-resistant adhesive tape is pasted to form a mold, and a light-transmitting resin that covers and integrates both the elements and a light-shielding resin that covers the outer periphery thereof are molded.

<Conventional technology> A photocoupler couples elements together through light.
Since the signal from the light emitting element side is transmitted to the receiving side, the element structure requires that at least the light transmitting part be connected with a translucent material, and it is also necessary to prevent moisture from entering from the outside and prevent external disturbances. It must be coated with a light-blocking material to block light. For this reason, a resin mold structure as shown in FIG. 2 has conventionally been adopted. That is, the opposing light transmitting parts of the light emitting element 1 and the light receiving element 2 bonded to the lead frames 5, 5, respectively, are combined with a transparent resin 3 such as silicone resin, and the outer periphery thereof is coated with black epoxy resin or the like. It is molded with light-shielding resin 4.

<Problems to be solved by the invention> However, in such a photocoupler, the light from the light emitting element 1 is directly transmitted to the light receiving element 2, so the transmission efficiency is high. Since the distance is short and the interface state between the two resins 3 and 4 is unstable, it has been difficult to obtain a high dielectric strength voltage. In addition, since the height of the wire connecting the lead frames 5, 5 and the light emitting element 1 and the light receiving element 2 is greatly affected by variations in assembly, the minimum distance between the electrodes between the light emitting element and the light receiving element is It was difficult to accurately manage the distance.

The present invention was devised in view of the above-mentioned problems, and aims to provide a reflective photocoupler with excellent dielectric strength.

<Means for Solving the Problems> Thus, according to this invention, a light emitting element and a light receiving element are mounted on a lead frame in one plane and arranged in parallel, and a transparent element is coated and integrated with the light emitting element and the light receiving element. It has a photoresist and a light-shielding resin that further covers its outer periphery, and is interposed between the light-transmitting resin and the light-shielding resin on the bottom side of the lead frame to serve as a receiving tray for the light-transmitting resin. , a heat-resistant adhesive tape with a concave downward surface is attached to the lead frame.

<Function> With the above configuration, the present invention allows the minimum distance between the electrodes between the light emitting element and the light receiving element to be controlled only by the precision of the lead frame cutting die, and the heat resistant adhesive tape that serves as a tray for the light transmitting resin allows the light transmitting The heat-resistant adhesive tape can easily maintain the shape required for reflection during coating with the transparent resin, and the concave surface of the tape can provide a sufficiently long interface distance between the light-transmitting resin and the light-blocking resin. Therefore, it is possible to improve the dielectric strength voltage.

<Example> An example of the photocoupler according to the present invention will be described in detail below.

FIG. 1 is a sectional view of an embodiment of a photocoupler according to the present invention. In the figure, 1 is a light emitting element, 2
3 is a light-receiving element, 3 is a light-transmitting resin that covers and integrates the light-emitting element 1 and the light-receiving element 2, 4 is a light-shielding resin that further covers the outer periphery thereof, and 5 is a lead frame. A heat-resistant adhesive tape 6 having a concave downward surface is interposed between the light-transmitting resin 3 and the light-shielding resin 4 on the bottom side of the lead frames 5, 5.

That is, the light emitting element 1 and the light receiving element 2 are arranged in parallel on the lead frames 5, 5 in the same plane and die-bonded, and then connected using wire lines. Then, a heat-resistant adhesive tape 6 is bonded to the bottom surfaces of the lead frames 5, 5 by thermocompression so as to form a concave surface downward. Incidentally, an epoxy adhesive is applied to the surface of the heat-resistant adhesive tape 6, and a polyester film is further attached as a protective film. After this thermocompression bonding, the light-emitting element 1 and the light-receiving element 2 are covered with the light-transmitting resin 3 while filling the inside of the concave surface of the heat-resistant adhesive tape 6 with the light-transmitting resin 3, in other words, using the heat-resistant adhesive tape 6 as a saucer. Unify. At this time, the heat-resistant adhesive tape 6 serving as a tray for the translucent resin 3 prevents the translucent resin 3 from sagging, etc., thereby easily maintaining the covering shape necessary for reflection. Thereafter, the outer periphery is molded with light-shielding resin 4 such as epoxy resin. As this epoxy resin, in order to enhance the light reflection effect at the interface with the translucent resin 3, it is appropriate to use a white epoxy resin containing a scattering filler.

<Effects of the invention> According to the invention, in the case of a reflective type, by pasting a heat-resistant adhesive tape to the bottom of the lead frame so as to form a concave surface downward, it can be easily used as a saucer when covering with a translucent resin. In addition to maintaining the shape necessary for reflection, the creepage distance between the light-transmitting resin and the light-shielding resin can be increased, and the dielectric strength can be improved, making it extremely easy to increase the dielectric strength of the photocoupler.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of a photocoupler according to the present invention, and FIG. 2 is a sectional view of a conventional photocoupler. 1: Light-emitting element, 2: Light-receiving element, 3: Translucent resin, 4: Light-shielding resin, 5: Lead frame, 6:
Heat-resistant adhesive tape.

Claims (1)

[Scope of utility model registration request] A light-emitting element and a light-receiving element mounted on a lead frame in one plane and arranged in parallel, a light-transmitting resin that covers and integrates the light-emitting element and the light-receiving element, and a light-shielding resin that further covers the outer periphery thereof. In the reflective photocoupler, between the light-transmitting resin and the light-blocking resin on the bottom side of the lead frame,
A photocoupler characterized in that a heat-resistant adhesive tape is provided with a concave surface on the lower side which is attached to the lead frame and serves as a receptacle for the translucent resin.