US Patent 7492025 Photo coupler

A photo coupler includes a semiconductor laser, a semiconductor light-receiver, a resin protector, a reflective film, a light pipe, and electrodes. The light pipe is made of resin, has a rectangular parallelepiped shape, and is provided so as to surround an outer circumferential portion of the semiconductor light-receiver. On a center portion of an upper surface of the light pipe, a recessed portion shaped in a frustum of quadrangular pyramid tapered toward the semiconductor light-receiver is formed. The reflective film is shaped in a frustum surface of pyramid tapered toward the semiconductor light-receiver, and is formed on side surfaces of the recessed portion.