Patent ID: 6563098
Filing Date: 2003-05-13
Classification: G01B,G02B

Abstract:
A high-precision displacement measurement device for projecting a spot of light from a light source on an object whose displacement is to be measured and measuring a relative displacement of the object from a displacement of the projected light spot, said device comprising:a unit displacement sensor based on a confocal theory, said unit displacement sensor including a transmission lens for transmitting a divergent beam of light emitted from said light source through a slit or pinhole with a certain size, a collimating lens for collimating said light beam transmitted through said slit or pinhole, an object lens arranged between said collimating lens and said object, a beam splitter for splitting a beam of light, reflected from said object to said transmission lens, according to a wavelength, and a photodetector for detecting a light intensity of said light beam split by said beam splitter; and actuation means for finely moving said unit displacement sensor to always maintain optical signals detected by said photodetector at the maximum intensity.