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What is the internal structure of a photocoupler?

For photocouplers, the structure inside the package also varies depending on the condition such as the required isolation performance, package size, and internal chip size.

1. Face-to-face type in single mold

The LED-mounted frame and the photodetector-mounted frame face each other (transmissive) and are molded. Silicone resin is used for the optical transmission part between the LED and the photodetector.

2. Face-to-face type in single mold (with a polyimide film)

To increase an isolation voltage between an input and an output, a polyimide film is inserted between the LED and the photodetector.

3. Face-to-face type in double mold

This photocoupler adopts a face-to-face type structure, and is white-molded inside and black-molded outside. Resin with high infrared light transmittance is used for the white mold of the optical transmission part.

4. Reflective type

This photocoupler adopts a structure that has the LED-mounted frame and the photodetector-mounted frame on the same plane. It is called "reflective type" because LED light reflected inside silicone resin reaches the photodetector.

①Body
②Window
③Detector
④LED
⑤Film

Transmissive single mold

Face-to-face type
single mold

Transmissive single mold with film

Face-to-face type
single mold
with film

Transmissive double mold

Face-to-face type
double mold

Reflective type

Reflective type

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·Before creating and producing designs and using, customers must also refer to and comply with the latest versions of all relevant TOSHIBA information and the instructions for the application that Product will be used with or for.