| 摘要 |
An optical pickup apparatus for information recording and/or reproduction on different optical information recording media with compatibility among these media, the optical surface of a first objective lens and the optical surface of a second objective lens are formed only of a refractive surface. The second objective lens is used in common for the first light flux with a wavelength of lambda1 and the second light flux with a wavelength of lambda2, but in the case where the protective substrate t2 of the second optical information recording medium and the protective substrate t3 of the third optical information recording medium are the same, it is not necessary to take the difference in thickness of the protective substrate into consideration. Chromatic aberration based on the difference in wavelength between the first light flux and the second light flux can be corrected by displacing the second coupling lens.
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