| 摘要 |
PURPOSE:To measure the surface shape of an object surface with high accuracy by employing a shearing system and a fringe scanning system and erasing aberrations characteristic to an interferometer during an analysis of fringes. CONSTITUTION:Luminous flux from a laser light source 50 are passed through a light quantity adjuster 51 and a total reflecting mirror 52 and diverged by a diverging lens 53, and the light is reflected by a beam splitter 54 and collimated by a collimator 55 to illuminate the object surface 57 through a condenser lens 58. Reflected light from the object surface 57 travels backward and the beam splitter 58 transmits part of it and reflects the remainder; and the transmitted light is reflected by a total reflecting mirror 60 driven by a piezoelectric element 61 to return a beam splitter 58 and the reflected light, on the other hand, is shifted literally by a total reflecting mirror 59 to return the beam splitter 58, which superpose both light beams again, so that they interfere with each other. The luminous flux passes through a relay lens 62 and a total reflecting mirrors 63 to form interference fringes on an image pickup element 65, which converts the fringes into an electric signal of image information; and the signal is digitized by an A/D converter 66 and a computer 67 eliminates the remaining aberrations characteristic to the interferometer to compute the surface shape of the object surface 57. |
