To quickly analyze and measure the shape of a surface to be inspected with high accuracy by simultaneously observing interference fringes and taking the picture of the surface by providing a reference light reflecting surface having such wavelength selectivity that the surface becomes transparent against the other wavelength region than the wavelength region of irradiating light on the side of the surface of a standard plate facing the surface to be inspected and taking the picture of the actual state of the surface to be inspected by means of an image pickup means provided on the rear surface side of the standard plate.
A standard plate 7 and a surface 4 to be inspected are symmetrically positioned with respect to the optical axis of an interferometer device and the device is constituted so that the device may become symmetrical as a whole. The standard plate 7 is formed by vapor depositing a light reflecting film having wavelength selectivity and a prescribed thickness on the surface of a transparent glass plate facing the surface 4 to be inspected. The light reflecting film has high reflectance against light rays in and near the wavelength region of the light emitted from a light source 1 and high transmittance against the light rays in the wavelength region of the other visible light rays. Since the light rays in and near the wavelength region of the light emitted from the light source 1 pass through the reflecting surface 7a and the transparent glass plate of the standard plate 7, the picture of the actual state of the surface 4 can be taken with a TV camera 22.
MATSUDA SHINICHI
SAITO TAKAYUKI
KOBAYASHI FUMIO
