| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical head device reducing the cross-talk when reproducing multilayered optical disks. <P>SOLUTION: In an optical head which reflects the light from the light source on the information recording layer of an optical disk and guides it to the photo detector, a hologram element is disposed in the light path extending from the optical disk to the optical detector. The hologram element brings the incident linearly polarized light into a state that the polarized directions of the zeroth-order diffracted light travelling straight from the hologram element and of the first-order diffracted light perpendicularly cross each other at the photo detector. Since the interference does not develop even when the signal light to turn into the first-order diffracted light and the stray light to be the zeroth-order diffracted light overlap on the photo detector, the cross-talk is reduced, and an optical head device stabilizing the reproduction precision can be provided. <P>COPYRIGHT: (C)2010,JPO&INPIT |
