Patent ID: 8859977
Filing Date: 2014-10-14
Classification: G01B,G01N,G21K

Abstract:
1. A wavefront measuring apparatus comprising: an optical element arranged to form a periodic pattern by light emitted from a light source; a detector having a plurality of pixels to detect the light that enters the detector from the optical element; and a computer configured to compute, based on detection results of the detector, wavefront information at a plurality of positions in a wavefront of the light having transmitted through or having been reflected by a specimen, wherein the detector detects a first periodic pattern formed by the light from the optical element, and a second periodic pattern formed by the light from the optical element and having a phase shifted with respect to a phase of the first periodic pattern, and wherein the computer computes the wavefront information at one of the plural positions by using: a detection result detected in a first pixel of the plural pixels at time of detecting the first periodic pattern; a detection result detected in a second pixel of the plural pixels at the time of detecting the first periodic pattern, the second pixel being positioned within three pixels from the first pixel; and a detection result detected in the first pixel at time of detecting the second periodic pattern.