| 摘要 |
PURPOSE:To reduce for an optical system to affect signal processing, by optimizing an output signal level of an photoelectric converter section by regulating a light quantity of lighting, in an apparatus for processing signals after a member to be inspected is lighted and the reflected light is photoelectrically converted. CONSTITUTION:Light from a source 10 is lighted onto a member to be inspected (semiconductor wafer) 2 through a lens 9, a diaphragm 8a (or 8b), a lens 7, a composite prism 6, and a lens 5. The reflected light from the member 2 is incident to an image pickup tube 15 through the lens 5, the composite prism 6, a lens 11, a mirror 12, a glass plate 13 and a lens 14, to be photoelectrically converted by the image pickup tube 15. In this case, a light quantity of the source 10 is automatically controlled so that an output signal level of the image pickup tube 15 can be optimized. Thus the signal processing section being connected to a post-stage of the image pickup tube can be escaped from being affected from the optical system, an AGC circuit, etc., can be eliminated, and deterioration of the S/N ratio can be prevented. |
