Patent ID: 9441950
Filing Date: 2016-09-13
CPC Classification: G01B

Claim Text:
1. An optical measurement apparatus comprising: a light source to emit laser light; a high-frequency superimposing unit to superimpose a high-frequency current on a driving current to drive the light source; a light branching element to branch the laser light into signal light and reference light; an objective lens to condense and irradiate the signal light on a measurement object; a condensing position scanning unit to scan a condensing position of the signal light by scanning at least the objective lens; a light path length adjusting unit to adjust a light path length difference between the signal light and the reference light, the light path length adjusting unit including a mirror to reflect the reference light and a movement stage to move the mirror, and the light path length difference is adjusted by moving the movement stage; an interference optical system which combines the signal light reflected or scattered by the measurement object and the reference light, and generates a plurality of interference lights different from each other in phase relation; and a photodetector to detect the interference lights, wherein in a state where the high-frequency current is not superimposed on the driving current, the light path length difference between the signal light and the reference light is adjusted by the light path length adjusting unit, and when the high-frequency current is superimposed on the driving current by a high-frequency superimposing unit, measurement is performed.