摘要 |
A device for detecting the position of a light source of an illumination optical system. The position detecting system of the present invention is particularly suitable for use in the detection of any positional deviation, from a correct position, of a Hg lamp used in a semiconductor device manufacturing exposure apparatus. The device includes an optical system for forming a plane which is optically conjugate with the surface of an object to be illuminated and a member disposed in such a plane and having a pinhole. The light emitted from the light source and passed through the pinhole is received by a photodetector, whereby the positional deviation of the light source is accurately detected. In another aspect of the invention, the detected positional deviation of the light source is automatically adjusted.
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