| 摘要 |
<p>A converging optical element for use in an optical pickup apparatus reproducing and/or recording information on a first optical disc using a first light flux with a wavelength λ1 emitted by a first light source, reproducing and/or recording information on a second optical disc using a second light flux with a wavelength λ2 emitted by a second light source, and reproducing and/or recording information on a third optical disc using a third light flux with a wavelength λ3 emitted by a third light source, the converting optical element includes: a phase structure arranged on at least one surface of the converging optical element, wherein when f3 is a focal length of the converging optical element for the third light flux, the focal length f3 satisfies a predefined condition.</p> |
