| 摘要 |
PROBLEM TO BE SOLVED: To provide a recording and reproducing device that can to suppress spherical aberration even if the numerical aperture(NA) is enlarged and also to provide an optical head. SOLUTION: The device 1 for recording/reproducing information signal on an information recording medium that has a light transmission layer on a recording layer for recording information signals, is provided with a light source 10 for emitting a light beam, objective lenses 23, 24 for converging the light beam from the light source 10 on the recording layer through the light transmission layer, at least two optical elements 18, 19 that are arranged between the light source 10 and the objective lenses 23, 24 and that are equipped with a prescribed refracting power, and a transfer means for moving one optical element 18 for the purpose of varying an interval between the optical elements 18, 19 so that the spherical aberration is canceled in accordance with the thickness of the light transmission layer. |
