| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup realizing an increase in light quantity reaching a photodetector while ensuring the light quantity used for read and write in an optical recording medium and an optical disk device. <P>SOLUTION: A diffraction optical element 17 having a first diffraction grating-free region and a second diffraction grating-formed region is arranged on an optical path reaching an object lens 15 from a light source 11. A light beam at a place corresponding to the first region is not diffracted, resulting in preventing a decrease in the light quantity of the light beam reaching the optical recording medium 18. The light beam at a place corresponding to the second region is diffracted for convergence on the photodetector 16. Thus, the photodetector 16 receives light having higher power compared with a conventional optical system in which part of diffused light is made incident on the photodetector 16. <P>COPYRIGHT: (C)2003,JPO |
