SMALL OPTICAL MICROPHONE/SENSOR

摘要

PROBLEM TO BE SOLVED: To provide a small optical microphone/sensor by which a distance up to a reflecting surface and/or a physical property of the reflecting surface are measured. SOLUTION: The small optical microphone/sensor 2 is provided with a light source 4 which is coupled to an optical waveguide 6 used to transmit a light beam through the optical waveguide, and a photodetector 18 which is arranged and installed so as to receive reflected light from the reflecting surface. An end on one side of the waveguide 6 is provided with a face 12 whose tip having an angle decided by Snell's law of refraction of sinα1/sinα2=n2/n1is sharp. The reflecting surface is arranged and installed at an optimum distance which is decided by an angleα2and which is optimum for the face 12 having the sharp tip. The outer face of the waveguide has a means 19 which is adjacent at least to the face having the sharp tip and which is used to prevent light waves colliding with the surface from being reflected so as not to be returned to the waveguide. COPYRIGHT: (C)2003,JPO