Patent ID: 6992779
Filing Date: 2006-01-31
Classification: G01B

Abstract:
1. An interferometer apparatus for both low and high coherence measurement, the interferometer apparatus being of Fizeau type adapted to irradiate a reference surface with light from a light source, irradiate a sample separated by a predetermined distance from the reference surface with light transmitted through the reference surface, and yield wavefront information of the sample according to interference of light between the reference surface and the sample; wherein, when carrying out low coherence measurement by using a low coherent luminous flux outputted from the light source, the sample is interferentially measured such that the low coherent luminous flux is passed through a path-matching passage for dividing the low coherent luminous flux into first and second paths, while the optical path length difference between the respective luminous fluxes passed through the two paths equals twice the optical distance between the reference surface of the interferometer apparatus and the sample; and wherein, when carrying out high coherence measurement by using a high coherent luminous flux outputted from the light source, the sample is interferentially measured such that the high coherent luminous flux is made incident on at least the sample side of the path-matching passage at a position coaxial with the low coherent luminous flux, while the reference surface and the sample are irradiated with the high coherent luminous flux.