| 摘要 |
PURPOSE:To remove a black spot defective part in a highly accurate manner without inflicting an injury on the non-defective part connected or adjoined to the defective part by a method wherein, in the dry photographic plate on which a high resolution photographic emulsion is coated, a YAG laser beam is made to irradiate on the black spot defective part through a slit and a focusing lens. CONSTITUTION:The laser beam 2 of the wavelength of 0.53mum picked out from an Na:YAG laser oscillator 1 is expanded by a beam expander 3, and after it has been reflected using a reflecting miror 4 and passed through a slit 5, the laser beam is focused by a focusing lens 6, and it is made to irradiate on the region corresponding to the black spot defective part located on the silver emulsion surface of a focusing emulsion mask 7. As a result, the emulsion layer of 2-10mum in thickness can be removed from a glass surface. Also, as the focusing spot diameter is small, the correction of a microscopic pattern can be performed, the width of pulse is as short as several ns, and as the irradiation energy per one pulse is small, a defective part 10 can be removed without inflicting an injury on a non-defective part 9 which is connected or adjoined to the defective part. |
