| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup compatible between a CD and a DVD by one simple hologram element and an optical disk device on which the optical pickup is mounted. <P>SOLUTION: A semiconductor laser 1 emits laser beams of two wavelengths for a CD and a DVD and irradiates the laser beams to an optical disk via an object lens 8. A hologram element 9 separates a light beam reflected from the optical disk into 0th order diffracted light and diffracted light of positive and negative orders and introduces nearly symmetric defocusing aberration to the diffracted light of positive orders and the diffracted light of negative orders. Each light receiving part of a photodetector 10 is arranged such that it receives, for the diffracted light of positive and negative orders, one diffracted light in a convergence state and the other diffracted light in a blurred state. Then, a focus error signal is generated from the diffracted light in the convergence state and a tracking error signal is generated from the diffracted light in the blurred state. <P>COPYRIGHT: (C)2012,JPO&INPIT |
