Patent ID: 7787349

Claim:
An optical pickup lens that focuses laser beams having different wavelengths λ 1 , λ 2 and λ 3 on at least three kinds of optical discs, comprising: a plurality of loop zonal recess or raised portions formed concentrically on at least one side of the optical pickup lens with a predetermined step height h different from adjacent loop zonal recess or raised portions, the plurality of loop zonal recess or raised portions being configured to generate phase differences, an individual aspherical surface being established in each of the plurality of loop zonal recess or raised portions, the plurality of loop zonal recess or raised portions being configured to compensate, by using an effect of refraction, wavefront aberration occurring when recording or reproducing an optical disc having a substrate thickness t 1 by the laser beam having the wavelength λ 1 and wavefront aberration occurring when recording or reproducing an optical disc having a substrate thickness t 2 by the laser beam having the wavelength λ 2 , the step height h causing a phase difference of about 0.15λ or smaller to the laser beam having the wavelength λ 3 when recording or reproducing an optical disc having a substrate thickness t 3 by the laser beam having the wavelength λ 3 .