Patent ID: 7317538
Filing Date: 2008-01-08
Classification: G01P,G01S

Abstract:
1. An optical movement information detector, comprising: a semiconductor light-emitting device for emitting coherent light; a first beam splitting device for splitting the light emitted from the semiconductor light-emitting device into at least three beams; an optical system for forming one spot on a surface of an object to be measured with use of the beams; a light detecting device for receiving diffused light coming from the spot; a signal processing circuit for processing a signal outputted from the light detecting device; and a detecting section for obtaining movement information on the object based on an output from the signal processing circuit; wherein the signal processing circuit includes: the detecting section obtains the moving information on the object based on three peak frequencies in a spectrum obtained by the Fourier transforming section, said three peak frequencies being attributable to a moving velocity of the object.