| 摘要 |
PURPOSE:To immediately sense an abnormality of an optical system and to prevent the soldering defect by the abnormality of the optical system by providing a temp. sensor on at least either of the optical system and a mask and monitoring the misalignment, etc., of the optical axis of the light beam in the optical system at all times. CONSTITUTION:The temp. sensors 31, 32 which sense the abnormality of the optical system 23 are provided in the part deviated from the light beam reflecting region of a 2nd plane mirror 25 of the optical system 23 and the light shielding part deviated from the light beam transmission region (through-hole) of the above-mentioned mask 27. The temp. sensor 31 senses an abnormally high direct irradiation temp. when the abnormality, such as generation of a deviation in the angle of a 1st plane mirror 24, arises in the optical system 23 and the light beam deviates from the normal light beam reflecting region of the 2nd plane mirror 25 and falls onto the temp. sensor 31. The temp. sensor 32 senses the extraordinary high mask temp. and the direct irradiation temp. of the light beam when the abnormality, such as generation of a deviation in the angle of the mirrors 24, 25 or a condenser lens 26 occurs and if the light beam deviates from the normal light beam transmission region of the above- mentioned mask 27 and abnormally heats the shielding part of the mask 27 or falls onto the temp. sensor 32. The stopping of the light source 21, etc., are executed and the optical system 23 is inspected when the abnormality is sensed. |
