| 摘要 |
PURPOSE:To semipermanently suppress the generation of fungi on the surfaces of optical parts without contaminating the optical systems and without lowering the optical performance thereof. CONSTITUTION:An ITO film 8 (or In2O3 film) is formed as a 1st film in an effective luminous flux diameter part 3 on a substrate 7 of the optical element and the peripheral part 4 thereof. An MgF2 film 9 is then formed as a 2nd layer on the effective luminous flux diameter part 3 on the 1st layer, an ITO film 8 as a 3rd layer and an MgF2 film 9 as a 4th layer respectively thereon. Then, the ITO film 8 of the 1st layer having the excellent fungiproofness prevents the generation and advance of the fungi from the periphery of the holding part of the optical element. |
