摘要 |
An apparatus for measuring displacement information of an object. The apparatus has a light source emitting a light beam, an electro-optical crystal member, a voltage applying system for imparting a predetermined frequency difference between light beams passing through two different areas in the electro-optical crystal member, and a light receiving system for receiving scattered light from the object to which the two light beams emergent from the electro-optical crystal member have been projected. The electro-optical crystal member is disposed so that a light beam from the light source may partly enter the two different areas to form the two light beams to which the predetermined frequency difference is imparted. The displacement information of the object is obtained from the scattered light received by the light receiving system.
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