Optical coupling device for a photo-semiconductor element and an optical fiber

Claim 1

An optical coupling device for a photo-semiconductor element having a light sensitive area and an optical fiber having one end face disposed opposite said light sensitive area of said photo-semiconductor element with a space therebetween wherein a reflection preventing film adapted to transmit light and to prevent optical reflection is disposed in contact with said light sensitive area to permit said light sensitive area to receive light emitted from the end face of said optical fiber, the improvement comprising a transparent light transmitting resin completely filling the space directly between said end face of said optical fiber and said reflection preventing film on said light sensitive area of said photo-semiconductor element whereby the light being transmitted by said light transmitting resin has a smaller angle of spread than in air and a film of light reflecting resin completely covering said transparent resin between the end face of the optical fiber and the reflection preventing film to prevent light from escaping outwardly from said transparent resin in the space between the end face of said optical fiber and said film on said light sensitive area of said photo-semiconductor element.