| 摘要 |
An optical pickup apparatus for reproducing information from or recording onto one of different kinds of optical information recording medium comprises a first light source for emitting first light flux whose wavelength is lambd1; a second light source for emitting second light flux whose wavelength is lambd2, wherein lambd2 is greater than lambd1; a converging optical system comprising an objective lens having an optical axis and divided three (first, second and third) portions; and a photo detector. The following conditional formula is satisfied for an amount of the first light flux not less than 30% of the total amount of the first light flux passing the first portion: 0.06>=SC1/f1>=0.002 where, in case that the first portion converges the first light flux on a first information recording plane, SC1 is a sine condition dissatisfaction amount of the first portion of the objective lens for a light flux at a height in the first light flux, and in case that the first portion converges the first light flux on a first information recording plane, f1 is a focal length of the first portion of the objective lens for a first light flux.
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