Optical transducer with a transparent shutter disk

Claim 1

An optical transducer for detecting the position of a movable member with respect to a fixed structure comprising a light source for generating a light beam, a photodetector for receiving said light beam, and a shutter member disposed between said light source and said photodetector, said shutter member having two faces which are parallel to each other, at least one of said two faces being provided with a plurality of light interrupting means for interrupting said light beam, separated by a plurality of light transmitting means which selectively transmit said light beam to said photodetector in response to the movement of said movable member, each one of said light transmitting means having a predetermined light transmitting area, wherein said photodetector comprises a plurality of photosensitive elements each one having a photosensitive area which is smaller than the light transmitting area of each one of said transmitting means, wherein said photosensitive elements are diffusely distributed over the region illuminated by said light beam which passes through said transmitting means, and wherein said interrupting means comprises a plurality of V-shaped elements provided on said at least one face of said shutter element and capable of totally deflecting the light incident thereon.