| 摘要 |
An optical pickup apparatus compatible with at least two types of optical recording media, using light beams having respective different wavelengths for recording and reading information, the optical pickup apparatus including two laser light sources to emit light beams having the different wavelengths, respectively, a holographic lens, including a holographic ring, to transmittal of the light beams emitted from the laser light sources in an inner region of the holographic ring, and diffracting a specific light beam among the light beams emitted from the laser light sources in an outer region relative to the inner region, an objective lens to focus the light beams passed through the holographic ring lens on the respective information recording surfaces of the two types of the optical recording media, optical elements to alter optical paths of the light beams reflected from the information recording surfaces of the optical recording media; and two photodetectors to individually detect optical information from the light beams incident from the optical elements. The optical pickup apparatus is used compatibly with optical recording media by using the holographic lens to eliminate spherical aberration generated when an optical recording medium is changed to another medium having a different thickness, thereby providing advantages which include ease in construction of the holographic lens and good mass-production capabilities.
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