| 摘要 |
PROBLEM TO BE SOLVED: To provide a technique capable of reducing color unevenness on a screen by increasing NA (thickness of light beam) while reducing the light amount to reduce unevenness in angle distribution for applying a light bulb.SOLUTION: In a variable diaphragm 10, a diaphragm body 20 is arranged so as to rotate on the central axis C for allowing the diaphragm to rotate indicated upper portion in the figure. The diaphragm body 20 comprises: a first opening 30; and second openings 40. The first opening 30 has a semicircular shape so as not to interfere a light beam LF in a state of open diaphragm. The second openings 40 are small holes disposed in the diaphragm body. When the diaphragm body 20 rotates on the central axis C for restricting rotation, the light amount allowed to pass through the first opening 30 and the second opening 40 is adjusted. |
