| 摘要 |
PURPOSE:To reliably and rapidly find a wave front aberration value, by measuring an interference fringe, obtained on a observing surface, in an alternating current and an optical manner. CONSTITUTION:Laser light, passing a stationary lambda/4 disc 8 through a collecting lens 1, a semitransparent mirror 2, and a lens 3 produces a circular polarized light to pass a rotary lambda/4 disc 9, it is reflected by a reflecting surface 5 to return through a reverse optical path, and passes the rotary lambda/4 disc 9 again. Thus, the polarized light, passing the stationary lambda/4 disc 8, results in an equivalence to that which passes a lambda/2 disc, and further passes the stationary lambda/4 disc 8 to form a rectilinear polarized light A equivalent to an azimuth of an intitial rectilinear polarized light. It reaches an observing surface 7, and an interference fringe is obtained resulting from the interference of it with light reflected by a semitransparent surface 3b of the lens 3. If the strength of the interference fringe is collected by a photoelectric element located on the observing surface 7, an electric signal of each bit so obtained is of a sine wave signal, the phase thereof produces that which depends on a phase of a photo wave at a temperature point, and a wave front aberration of a lens 4 to be tested can be found from a difference in phase. |
