PICKUP LENS AND UNIT INCLUDING THE SAME

PROBLEM TO BE SOLVED: To provide a pickup lens which is practicable to at least three types of optical disks.SOLUTION: A plurality of orbicular zones exist on one plane of a pickup lens. When the plane with the orbicular zones formed thereon is divided into a first region including an optical axis, a second concentrically circular region adjacent to the outside of the first region, and a third concentrically circular region adjacent to the outside of the second region, laser beams of wavelengths λ1, λ2, λ3 in a range corresponding to the first region converge on information recording media with substrate thicknesses t1, t2, t3, respectively, the laser beams of the wavelengths λ1, λ2 in a range corresponding to the second region converge on the information recording media with the substrate thicknesses t1, t2, respectively, while the laser beam of the wavelength λ3 in a range corresponding to the second region does not converge on the information recording medium with the substrate thickness t3, and the laser beam of the wavelength λ1 in a range corresponding to the third region converges on the information recording medium with the substrate thickness t1, while the laser beams of the wavelengths λ2, λ3 in a range corresponding to the third region do not converge on the information recording media with the substrate thicknesses t2, t3.