| 摘要 |
<p>PURPOSE:To carry out an inspection at high accuracy by splitting an incident light beam into a reference light beam to a reflecting mirror and an inspecting light beam to a specimen placed on a turnable table 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 specimen 14 is placed on the turnable table 16, which is turned so that the incident angle theta of the inspecting light beam from the spliter 44 with respect to the inspected part of the specimen 14 can be equal to the measuring direction, and the direction of the specimen 14 is adjusted. Then 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, are photoelectrically converted by a common photoelectrical converter 22. Then a detecting circuit compares 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, and obtains the optical characteristic of the specimen 14. Accordingly the inspection offering the reflectance and transmissivity of the optical characteristics at high accuracy can be possible without the fluctuation due to the time difference and the difference between characteristics of the converter 22.</p> |
