To realize clear marking, transfer, etc., regardless of the material of a work by displaying a pattern in a normally open mode and also arranging a space filter between a TN liquid crystal mask and the work.
A pulse oscillating Nd:YAG laser 1 emits a laser beam 2 of linear polarized light. The laser beam 2 is emitted through an expansion optical system 3 to a liquid crystal mask 4 in which a pattern is displayed. After being split into a laser beam 5 containing pattern information and unnecessary light 12 by a polarizing beam splitter 6, the laser beam 5 is emitted onto a work 8 through an image-forming lens 7, so that the pattern 9 is marked. Then, the pattern 9 is displayed in a normally open mode. Simultaneously, a space filter 14 is arranged between a TN liquid crystal mask 4 and the work 8. As a result, because of no shielding by the filter, marking with a uniform depth is obtained.
SARUTA HIKARI
MERA KAZUO
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