| 摘要 |
PROBLEM TO BE SOLVED: To eliminate local bias of transmissivity and to suppress reflection of finish dimension errors to transmissivity errors. SOLUTION: A density filter has a transmissive part transmitting light and a light shielding part shielding light. A transmitting light quantity is 100% in an area except for a peripheral part and is gradually lowered at the peripheral part from 100% to 10%. Basic cells 40, respectively having two light shielding patterns 44 on a transmissive body base 43 or two transmissive patterns 42 on a light shielding body base 41, are arranged regularly at the periphery part. The area ratio of a transmissive pattern area and a basic cell area is set to be equal with designed transmissivity in an area, where the designed transmissivity is 0 to 50%. The area ratio of a light shielding pattern area and the basic cell area is set equal to (1-designed transmissivity) in an area, with a designed transmissivity of 50 to 100%. |
