OPTICAL PICKUP APPARATUS AND OPTICAL ELEMENT

摘要

PROBLEM TO BE SOLVED: To provide an optical pickup apparatus which is used for recording/playing back three kinds of optical information recording media using different wavelengths and having different protective substrate thicknesses, suppresses the occurrence of various aberrations and can reduce the number of parts, and to provide an optical element.

SOLUTION: The optical pickup apparatus is constituted to perform recording and/or reproduction of information by using light beams of wavelengths of λ1 to λ3 for first to third optical information recording media. A diffractive optical element having a first diffractive structure is arranged in the common optical path of first to third light sources. When the reproduction and/or recording of the information is performed to the individual optical information recording media, all of the above light beams are made incident at the same angle on the diffractive optical element such that a converged light spot by the m-th (m is a natural number) diffracted light generated by the diffractive optical element is formed on the first optical information recording medium and that the converged light spot by the n-th (n is a natural number which is ≠m) diffracted light generated by the diffractive optical element is formed on the second information recording medium.

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