| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve weatherability of an optical element in which a structure finer than a using wavelength is formed on a base member having a curved surface. <P>SOLUTION: The optical element has a structure for suppressing reflection formed on at least one surface of the base member 012. The surface where the structure is formed in the base member is a curved surface. The structure has: an irregular structure layer 011 which has the irregular structure of a pitch smaller than the shortest wavelength of a using wavelength range, wherein the width of a recessed part and a projected part is changed in a thickness direction; and at least one intermediate layer 013 formed between the irregular structure layer and the base member by a material different from that of the irregular structure layer, and satisfies a condition: ¾n<SB>A</SB>-n<SB>sb</SB>¾≤0.1. The equivalent refractive index of the part closest to the base member side in the irregular structure layer is denoted by n<SB>sb</SB>, and the refractive index of the intermediate layer in contact with the irregular structure layer in the at least one intermediate layer is denoted by n<SB>A</SB>. <P>COPYRIGHT: (C)2010,JPO&INPIT |
