| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an aberration correcting element suppressing light quantity loss by the transfer defects of the adjacent zonal level differences of a diffraction lens while sufficiently correcting the color aberration of an objective lens and to provide an optical pickup device and a recording and reproducing device for which a manufacture cost is suppressed. <P>SOLUTION: The aberration correcting element has 2-group 3-lens constitution composed of the diffraction lens 4a arranged between a light source 2 generating the light of a wavelength equal to or less than 500 nm and the objective lens 5 whose image side numerical aperture is equal to or more than 0.8 and provided with a diffraction surface where a diffraction structure composed of a plurality of concentric zonal level differences is formed on an optical surface, and a doublet lens 4b for which the positive lens of a relatively large Abbe number and the negative lens of a relatively small Abbe number are joined, and satisfies Pλ2>Pλ0>Pλ1 (Pλ0: the paraxial power of the aberration correcting element in the light of a prescribed wavelength, Pλ1: the paraxial power of the aberration correcting element in the wavelength shorter than the light of the prescribed wavelength by 10 nm, Pλ2: the paraxial power of the aberration correcting element in the wavelength longer by 10 nm than the light of the prescribed wavelength. <P>COPYRIGHT: (C)2004,JPO |
