| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical element, an optical pickup device, and an optical information recording and reproducing device in which yield in mass production of a laser light source is improved by enabling suppression of variation quantity of spherical aberration per unit wavelength variation and reduction of a manufacturing cost can be performed. <P>SOLUTION: This optical element has at least one by one each of optical planes in which diffraction structure in which diffractive light of n<SB>1</SB>order is generated when a first luminous flux of wavelength λ<SB>1</SB>(nm) is made incident and diffractive light of n<SB>2</SB>order (¾n<SB>1</SB>¾≥¾n<SB>2</SB>¾) is generated when a second luminous flux of wavelength λ<SB>2</SB>(nm)(λ<SB>2</SB>>λ<SB>1</SB>) is made incident is formed, and optical path difference giving structure constituted of a plurality of ring bands divided by difference in level in the direction of an optical axis is formed. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
