| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup device and an objective lens having a reduced phase shift of wave aberration, the objective lens being used for both recording and playing back information on various optical information recording media such as CDs and DVDs. <P>SOLUTION: In an objective lens, forming a diffraction structure having a diffraction ring zone blazed with respect to a wavelength λ0 in both a central area and a peripheral area of the objective lens causes wave aberration corresponding to the ring shape even in the peripheral area, but the wave aberration phase in the peripheral area can substantially coincide with that in the central area. Thus, making the average values of the wave aberration coincide between the central and peripheral areas can reduce the phase shift to zero or less than 0.05λ1, which can improve the wave aberration. <P>COPYRIGHT: (C)2012,JPO&INPIT |
