OPTICAL PICKUP DEVICE, RECORDING/REPRODUCING DEVICE HAVING THE OPTICAL PICKUP DEVICE, OPTICAL DEVICE, METHOD FOR RECORDING/REPRODUCING INFORMATION, OPTICAL SYSTEM, LENS, DIFFRACTING OPTICAL SYSTEM FOR OPTICAL DISK, REPRODUCING DEVICE AND OBJECT LENS FOR OPTICAL PICKUP DEVICE

摘要

PROBLEM TO BE SOLVED: To obtain an optical pickup device in which an aberration is corrected with simple constitution, a recording/reproducing device having the optical pickup device, an optical device, a method for recording/reproducing information, an optical system, a lens, a diffracting optical system for an optical disk, a reproducing device and an object lens for the optical pickup device.;SOLUTION: A spherical aberration is corrected by offsetting an action of a diffracting surface against an action of refractive surface to each of three light sources 11, 12 and 13 having different wavelengths including an optical surface in which a diffracted zonal lens is provided on the refractive surface of the object lens 1. Also, a loss of light quantity is reduced by using 1st order diffracted light as diffracted light with respect to light from the light sources 11, 12 and 13 of three wavelengths. Also, the object lens is provided with a diffracted pattern in at least one surface, when luminous fluxes from the light sources of different wavelengths are condensed on an information recording surface, 1st order diffracted light from the diffracted pattern is used in reproducing of a plurality of recording media. +1st order diffracted light is used or -1st order diffracted light is used as utilized diffracted light depending on the condition of the recording medium.;COPYRIGHT: (C)2002,JPO