Automatic focusing apparatus

摘要

PCT No. PCT/JP78/00052 Sec. 371 Date Aug. 16, 1979 Sec. 102(e) Date Jun. 20, 1979 PCT Filed Dec. 13, 1978 PCT Pub. No. WO79/00400 PCT Pub. Date Jul. 12, 1979.A automatic focusing apparatus is disclosed for automatically focusing a focal point on an object substrate wherein the pn junction of an emitting part of a semiconductor ray source itself, has the effect of a pin-hole in order to eliminate a complicated setting of a position of a pin-hole panel whereby variation of the output of the semiconductor ray source caused by reflective ray is detected by a phase detector and the output is applied to an actuator to carry out an automatic focusing.