| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a diffractive optical element that can regulate an aperture properly for three types of discs of a high density optical disk employing a violet laser light source, a DVD, and a CD, and to provide an optical pickup apparatus equipped with the diffractive optical element. <P>SOLUTION: This optical pickup apparatus PU 1 is equipped with the diffractive optical element arranged in a common optical path for 1st-3rd light fluxes, and the optical surface of the diffractive optical element is divided into 1st-3rd areas, and the 2nd area and 3rd area are provided with a 1st diffractive structure 10 and a 2nd diffractive structure 20, respectively. Each of the 1st-3rd light fluxes having passed through the 1st area forms a light converged spot, respectively on the information recording surface of the prescribed optical disk, the 1st light flux and the 2nd light flux having passed through the 2nd area also form converged spots, respectively, the 3rd light flux having passed through the 2nd area does not form the converged spot, and either one of the 1st light flux and 2nd light flux having passed through the 3rd area forms a converged spot, and none of another light flux and the 3rd light flux having passed the 3rd area forms a converged spot. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
