INTERFEROMETER PHASE MEASUREMENT DEVICE, INTERFEROMETER PHASE FLUCTUATION CORRECTION DEVICE AND MEDIUM FLUCTUATION CORRECTING DEVICE

摘要

PROBLEM TO BE SOLVED: To reduce a phase error caused by an optical path displacement by obtaining phase deviation of interference fringe that follows an optical path deviation on the basis of the optical path position detected by an optical path position detecting means. ;SOLUTION: An optical path position detecting device 11 contains a photodetector which comprises for photodetecting areas. Incident light is photodetected at each photodetecting area, and the intensity of the light incident on the area is detected. With an arbitrary direction orthogonal to an optical path assumed as an X direction and a direction orthogonal to the optical path and the X direction assumed to be Y direction, a position detection circuit 12 outputs, based on the light intensity of four areas, the electric signal corresponding to the X direction component and the Y direction component, respectively, of an optical path displacement. The electric signal outputted from the circuit 12 enters a phase correction circuit 13, and at the circuit 13, the electric signal inputted from the circuit 12 is multiplied with a factor specific to a device which is set in advance to generate a phase correction data which indicates correction amount for phase. Based on the phase correction data, the phase signal from a receiver 9 is phase-shifted and outputted to a phase meter 14.;COPYRIGHT: (C)1997,JPO