Patent ID: 6765684
Filing Date: 2004-07-20
Classification: G01B

Abstract:
A surface shape measurement apparatus for measuring a shape of a surface of an object to be examined, the apparatus comprising:a stage on which the object is rested; a reference grid disposed in parallel to the stage; illumination means for illuminating the reference grid and projecting a grid pattern onto the surface of the object; photographing means for photographing the grid pattern projected onto the object surface through the reference grid and obtaining an image of moirÃ© fringes; rotation means for rotating the reference grid about an axis normal to a grid surface of the reference grid; and analysis means for analyzing the shape of the object surface based on information about a rotation angle of the reference grid and intensity of the moirÃ© fringes. wherein, with respect to each position in the obtained image, the analysis means obtains information about the rotation angles, one of which is determined when the moirÃ©-fringe intensity reaches a maximum and the other of which is determined when the moirÃ©-fringe intensity reaches a maximum, and the analysis means further analyzes the shape of the object surface based on the information about both the rotation angles.