| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce the cost of a device by providing such a structure as using an optical fiber bundle and providing photoelectric transfer elements adjacently to the base part thereof to reduce the necessary number of photoelectric transfer elements. SOLUTION: The scattered light generated from an area to be inspected on a photo mask 1 by the spot light of a laser beam LBa is received by light receiving lenses 8a, 9a, and guided to the end parts of first branched fiber parts 10a, 11a of an optical fiber bundle, respectively. The base parts are formed on the end parts opposite to the fiber parts 10a, 11a. Photoelectric transfer elements are continuously provided on the base parts, respectively, and the photoelectric transfer elements receive the lights emitted from the end surfaces of the base parts, respectively. The photoelectric transfer elements supply photoelectric transfer signals according to the light intensities of the received scattered lights to a signal processing circuit. The photoelectric transfer elements are provided not in the rear of slits 13a, 14a in the rear of a plurality of light receiving lenses 8a, 9a, but adjacently to the base part of the optical fiber bundle, whereby the necessary number of photoelectric transfer elements can be reduced.</p> |
