Patent ID: 7269119

Claim:
An optical pick-up apparatus comprising: a first light source emitting a first light flux having a wavelength of λ 1 , the first light flux being utilized for recording information on and/or reproducing from a first optical information recording medium including a first protective substrate having a thickness of t 1 ; a second light source emitting a second light flux having a wavelength of λ 2 , which is greater than λ 1 , the second light flux being utilized for recording information on and/or reproducing from a second optical information recording medium including a second protective substrate having a thickness of t 2 , which satisfies 0.8t 1 ≦t 2 ≦1.2t 1 ; a third light source emitting a third light flux having a wavelength of λ 3 , which satisfies 1.6λ 1 ≦λ 3 ≦2.2λ 1 and λ 3 >λ 2 , the third light flux being utilized for recording information on and/or reproducing from a third optical information recording medium including a third protective substrate having a thickness of t 3 , which 1.9t 1 ≦t 3 ≦2.1t 1 ; and an objective optical element having a diffractive structure on an optical surface of the objective optical element, wherein a diffraction efficiency E 1 of a first primary diffractive ray, which has the greatest diffraction efficiency among diffractive rays generated by the first light flux passing through the diffractive structure, is not less than 90%, a diffraction order n 1 of the first primary diffractive ray is an odd number, and an output power PW 3 , which is an output power of the third light source when the third light source emits the third light flux, is emitted is greater than an output power PW 1 , which is an output power of the first light source when the first light source emits the first light flux.