| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain: an optical element which has a good reflection preventing function in a large wavelength region and in a large incident angle range and generates little flares or ghosts when used in an optical system; and the optical system having the optical element. <P>SOLUTION: The optical element has the reflection preventing function in a use wavelength region including a visible range. The use wavelength region has a range whose longest wavelength λH is twice or more of its shortest wavelength λL. The optical element includes a reflection preventing structure constituted on at least one side of a light incoming/outgoing side of a substrate so that a fine uneven structure with the average pitch of the shortest wavelength λL or less is an outermost layer. The average pitch P of the fine uneven structure, the index of refraction n1 of a material forming the fine uneven structure, the average height h of the fine uneven structure, and the incident angle θ of a light flux entering the fine uneven structure from the air side are suitably set. <P>COPYRIGHT: (C)2010,JPO&INPIT |
