| 摘要 |
PURPOSE:To reduce the variance of the quantity of light, by making lens systems, each of which consists of two lenses, symmetrical with respect to an intermediate image in a projection system consisting of four lenses having the common axis and providing masks for controlling luminous fluxes at the outside of the axis for respective lens systems. CONSTITUTION:The projection system is an erect unmagnification system which transmits an object plane O to a focal plane C and consists of plural projection lensesI-1,I-2, II-1, and II-2 arranged on the common axis. The projection system is divided to the first lens systemIconsisting of two lensesI-1 andI-2 which forms an inverted intermediate image M and the second lens system II consisting of two lenses II-1 and II-2 which transmits the intermediate image M to the focal plane C, and these lenses are arranged in order from the object side. The first and the second lens systemsIand II are symmetrical with respect to the intermediate image M, and masks M3, M1, and M2 for controlling luminous fluxes at the outside of the optical axis are provided in the first and the second lens systemsIand II. |
