| 摘要 |
<p>PURPOSE:To attain a highly accurate test by splitting an incident light beam into a reference light beam to a reflecting mirror and an inspecting light beam to a specimen and comparing their reflected light beams. CONSTITUTION:The incident light beam from an incident optical system 8 is split into the reference light beam to the reflecting mirror 40 and the inspecting light beam to the specimen 14 by a beam spliter 44. The optical path of the reference light beam and that of the inspecting light beam are alternately intercepted, by a chopper 46 and the reflected light beam from the reflecting mirror 40 and that from a reflecting mirror 42 relaying the specimen 14, both of which make incident alternately through a chopper 46, are photoelectrically converted by a common photoelectric converter 22. Then an electrical signal available from the reflected light beam from the reflecting mirror 40 and that available from the reflected light beam from the specimen 14 are compared in a detecting circuit to obtain the optical characteristics of the specimen 14, whereby the fluctuation due to the time difference and the difference between characteristics of the photoelectrical converter 22 never occurs and the inspection providing the reflectance and transmissivity of the optical characteristics at high accuracy can be attained.</p> |
