Patent ID: 7193954

Claim:
An optical pickup apparatus, comprising: first, second and third light sources to emit light fluxes with wavelengths of λ 1 , λ 2 (λ 1 <λ 2 ) and λ 3 (λ 2 <λ 3 ) respectively; a light converging optical system including a first objective optical element and a second objective optical element, wherein the first objective optical element converges the light flux emitted from the first light source on a first information recording surface having a first information recording density D 1 of the first optical information recording medium through a protective layer with a thickness t 1 so as to record and/or reproduce information, the second objective optical element converges the light flux emitted from the third light source on a third information recording surface having a third information recording density D 3 (D 1 >D 3 ) of the third optical information recording medium through a protective layer with a thickness t 3 (t 1 <t 3 ) so as to record and/or reproduce information, and the first objective optical element or the second objective optical element converges the light flux emitted from the second light source on a second information recording surface having a second information recording density D 2 (D 1 >D 2 >D 3 ) of the second optical information recording media through a protective layer with a thickness t 2 (t 2 <t 3 ) so as to record and/or reproduce information; a lens holder holding the first objective optical element and second objective element therein; and a chromatic aberration correcting element which is arranged in an optical path where the light flux emitted by the first light source passes through, and corrects a chromatic aberration caused by a wavelength variation in a light flux emitted by the first light source.