Transmissive optical sensor and method of fabricating same

Abstract

A transmissive optical sensor and method of fabricating it are disclosed. The transmissive optical sensor includes a transmitter, a signal exciter and a receiver, which are sequentially stacked together. The transmitter includes first plastic encapsulation, and the receiver includes second plastic encapsulation. The first plastic encapsulation defines a light exit region, the second plastic encapsulation has a photosensitive element. The signal exciter has first and second optically transmissive ends. The light exit region is aligned with the first optically transmissive end, and the photosensitive element with the second optically transmissive end. Both the transmitter and the receiver are provided as plastic encapsulations with flat surfaces, which can be either vertically stacked, or horizontally juxtaposed, with the signal exciter. In this way, it is unnecessary to arrange the transmitter and the receiver on a PCB or couple them with a support frame, significantly reducing the size of the transmissive optical sensor.