| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a diffraction optical system using a free curved surface prism capable of favorably correcting chromatic aberration generated on the free curved surface prism across a wide wavelength range from a visible range to an infrared range, being unlikely to be affected by a manufacturing error of a diffraction optical device and facilitating the manufacture, and to provide an image pickup apparatus. <P>SOLUTION: A diffraction optical system comprises: a free curved surface prism 14; and a multilayered diffraction optical device in which a plurality of diffraction device elements 121 and 122 are layered on each other and a grating structure diffraction optical surface DM formed at the interface thereof. The diffraction optical system satisfies the conditional expression 0.005<(ΔNg+ΔNs)/2<0.45, where ΔNg is the refraction difference in the diffraction optical surface DM on a g line, and ΔNs is the refraction difference in the diffraction optical surface DM on an s line. <P>COPYRIGHT: (C)2012,JPO&INPIT |
