| 摘要 |
PURPOSE:To make it possible to measure the machined surface of a spherical surface in a mirror shape highly accurately, by projecting reference light on a hologram, and measuring the interference fringes of regenerated reference light and the reflected light from the surface to be measured. CONSTITUTION:Parallel light beams from a collimator lens 5 form a hologram 3 and function as reference light when regeneration is carried out. When the reference light such as this is projected on the hologram, part of the light is diffracted by the hologram 3 and reaches a surface to be measured 2. The part of the light is reflected and modulated by the surface to be measured 2 and reaches a screen 4. The remaining part of the light passes through the hologram 3, is diffracted and reaches the screen. This part forms a reference wave surface. Thus the interference fringes of the reference wave surface and the modulated wave surface are formed on the screen 4. The state of the surface to be measured can be measured highly accurately by expression DELTAh=(d/D)X(lambda/2), where (d) is a height of protruded part, D is a distance between fringes and lambda is a wavelength. |
