FOREIGN-BODY INSPECTION APPARATUS

摘要

PROBLEM TO BE SOLVED: To obtain a foreign-body inspection apparatus in which the transmittance of a filter can be changed over without a mechanical movement. SOLUTION: An inspection apparatus is constituted in such a way that it comprises a laser-light generation means 1 by which an object to be inspected is irradiated with laser light, that it comprises a detector 9 which is used to detect the reflection component of the laser light from the object to be inspected and that it comprises a filter 7 which is arranged at the previous stage of the detector 9 and which is used to attenuate the reflection component of the laser light from the object to be inspected. The filter 7 is constituted so as to comprise a liquid crystal panel in which a plurality of liquid crystal elements are matrix-arranged. The liquid crystal panel is formed in such a way that the plurality of liquid crystal elements are matrix-arranged. The transmittance of the liquid crystal panel can be changed automatically by adjusting a ratio in which the liquid crystal elements are blackened by applying a voltage. As a result, the transmittance of the filter 7 can be changed over without a mechanical movement.