Abstract: A hyper-resolution optical device which can focus a beam of light to a diameter less than the diffraction limit. The optical device has an optical system disposed on a transmissive substrate. One component in the optical system is a hyper-resolution optical component which passes or reflects light and which has a central portion which does not pass or reflect light, respectively. The hyper-resolution optical component can be integrated with the transmissive substrate. Such optical devices are particularly suitable for optical pick-up devices, laser printers, sensors.

Abstract: A reflective type photointerrupter including: a resin case formed with a light emitting chip mounting recess and a light receiving chip mounting recess; a metallic deposit wiring formed in the recesses; and a light emitting chip and a light receiving chip respectively mounted on the light emitting chip mounting recess and the light receiving chip mounting recess and sealed with a resin material; the recesses being arranged in side-by-side relation and partitioned by an intermediate wall.