| 摘要 |
<p>PURPOSE:To prevent malfunctions of a photocoupler due to an external light by providing a light preventing layer for preventing the external light in a resin sealed body and absorbing or reflecting the external light which has permeated through the resin sealed body of an enclosure by said light preventing layer so as to exceedingly reduce an incident light into a photo-detecting element. CONSTITUTION:In a resin sealed body 104 of a photocoupler, a film or a thin plate 11 made of a substance having a low transmission i.e., a smaller transmittance than that of the resin sealed body 104 and high light absorbing or light reflecting properties is provided. That prevents an external light permeating through the resin sealed body 104 and exceedingly reduces an incedent light into a photo-detecting element 112, thereby preventing an operation error. The light-preventing layer 11 can be formed only by putting a film-form resin on a frame when forming a light-transmitting resin part, so that a photocoupler suitable for automation and which can be fabricated at low cost is obtained. Furthermore, this light-preventing layer gives no bad influence upon the reliability and characteristics.</p> |
