Patent ID: 8121011

Claim:
A light converging element for use in an optical pickup apparatus in which reproducing and/or recording information is conducted for a first optical information recording medium equipped with a protective layer having a thickness t 1 by using a light flux having a first wavelength λ 1 emitted from a first light source, reproducing and/or recording information is conducted for a second optical information recording medium equipped with a protective layer having a thickness t 2 (t 2 >t 1 ) by using a light flux having a second wavelength λ 2 (λ 2 >λ 1 ) emitted from a second light source, and reproducing and/or recording information is conducted for a third optical information recording medium equipped with a protective layer having a thickness t 3 (t 3 ≧t 2 ) by using a light flux having a wavelength λ 3 (λ 3 >λ 2 ) emitted from a third light source, comprising: an optical surface having a plurality of optical functional zones, wherein a superposition type diffractive structure is formed within an optical functional zone including an optical axis of the plurality of optical functional zones such that a plurality of ring-shaped zones are formed concentrically around the optical axis and plural stepped sections shaped stepwise are formed within each ring-shaped zone, and wherein a diffractive order generated by the light flux having the first wavelength λ 1 passing through the superposition type diffractive structure, a diffractive order generated by the light flux having the second wavelength λ 2 passing through the superposition type diffractive structure, and a diffractive order generated by the light flux having the third wavelength λ 3 are all different from each other.