Patent ID: 8804130
Filing Date: 2014-08-12
Classification: B82Y,G01B

Abstract:
1. A displacement measuring device for measuring a change in a distance to a target object, comprising: a light irradiation section configured to irradiate, with laser light, a light transmissive particle provided at a predetermined distance from a surface of the target object; a movement section configured to move, relative to the target object, the particle held in an optical standing wave field generated by interference between light transmitted from the particle and light reflected from the target object; a sensing section configured to sense a movement signal occurring when the particle moves, relative to the target object, against confining force caused by the optical standing wave field; a calculation section configured to derive the change in the distance to the target object based on the movement signal and; an adjustment configured to adjust wavelength of the laser light, wherein the adjustment section adjusts the wavelength of the laser light to adjust a periodicity of the optical standing wave field.