| abstract |
(57) [Problem] To provide an optical slit having a constant slit width with good reproducibility without adjusting the slit width. SOLUTION: After forming an optically opaque Si film 2 on an optically transparent base 1 by a sputtering film forming apparatus or the like, Using photolithography technology and etching technology, a part of the Si film 2 in a portion that becomes a light path with a predetermined width is removed, and a slit 3 is formed. |