Objective lens, optical pickup apparatus and optical disc driving apparatus

An objective optical lens for use in an optical pickup apparatus for recording and/or reproducing information by converging a first light flux with a wavelength λ1 (λ1<450 nm) emitted by a first light source on an information recording surface of a first optical information recording medium through a first protective substrate with a thickness t1,

• for recording and/or reproducing information by converging a second light flux with a wavelength λ2 (1.5×λ1<λ2<1.7×λ1) emitted by a second light source on an information recording surface of a second optical information recording medium through a second protective substrate with a thickness t2 (t1≦t2) and
• for recording and/or reproducing information by converging a third light flux with a wavelength λ3 (1.9×λ1<λ3<2.1×λ1) emitted by the third light source on an information recording surface of a third optical information recording medium through a third protective substrate with a thickness t3 (t2<t3), the objective optical lens comprising:
• an optical surface divided into at least two areas including:
• a central area including an optical axis and comprising a first diffractive structure;
• and
• a peripheral area surrounding the central area and comprising a second diffractive structure,
• the objective lens is a single lens and is commonly used for the first to third optical information recording media,
• the objective lens converges diffracted light fluxes of the first to third light fluxes generated in the first diffractive structure onto information recording surfaces of the first to third optical information recording media, respectively,
• the diffracted light fluxes of the first to third light fluxes generated in the first diffractive structure have same diffraction order as each other, and
• the objective lens converges diffracted light fluxes of the first and second light fluxes generated in the second diffractive structure onto information recording surfaces of the first and second optical information recording media, respectively,
• the diffracted light fluxes of the first and second light fluxes generated in the second diffractive structure have different diffraction order as each other,
• wherein the objective lens further comprises a third diffractive structure,
• wherein the objective lens converges a 10th diffracted light flux among diffracted light fluxes of the first light flux generated by the third diffractive structure on the information recording surface of the first optical information recording medium,
• converges a 6th diffracted light flux among diffracted light fluxes of-the second light flux generated by the third diffractive structure on the information recording surface of the second optical information recording medium, and
• converges a 5th diffracted light flux among diffracted light fluxes of the third light flux generated by the third diffractive structure on the information recording surface of the third optical information recording medium.