| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup device which can exhibit the improved accuracy of signal detection and can be miniaturized. <P>SOLUTION: Optical beams of first to third wavelength emitted from first to third semiconductor laser elements 51 to 53 and reflected by an optical recording medium 61 are each diffracted by a hologram diffraction grating 70 of a hologram element 54. The optical beams of the first to third wavelength diffracted by the hologram diffraction grating 70 are received in different light receiving regions of a light receiving element 55, respectively. When the light receiving element 55 is obtained by, for instance, a semiconductor light receiving element, the optical beams of the first to third wavelength can be surely received, respectively, in the light receiving regions by forming the light receiving regions so that dimensions such as the junction depth of pn junction become dimensions corresponding to respective wavelengths. The accurate signal can be detected therefore based on the optical beam received in each light receiving region. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
