| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup device using the same light flux compatible with BD and HD by using objective optical elements and to provide an objective optical element. <P>SOLUTION: In the optical pick up device wherein a light source that emits a light flux of a wavelength of λ1, and the optical pickup device that records and reproduces information by converging the light flux on a first optical disk with a protective layer having a thickness of t1 and converging the light flux on a second optical disk with a protective layer having a thickness of t2 (t1<t2), the objective optical element is made of plastic, and its optical surface is divided into a plurality of concentric regions, and the regions include at least one region for the first optical disk and at least one region for the second optical disk, the light flux passing through the region for the first optical disk is converged on the first optical disk, and not converged on the second optical disk, the light flux passing through the region for the second optical disk is converged on the second optical disk and not converged on the first optical disk, and an optical path difference giving structure is formed in the region for the first optical disk. <P>COPYRIGHT: (C)2009,JPO&INPIT |
