| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup device which properly records/reproduces information on/from all of high-density DVDs and conventional DVDs and CDs while relaxing restrictions on the design and manufacturing tolerance of an objective optical element. <P>SOLUTION: By providing a chromatic aberration compensating function and a spherical aberration compensating function in beam expanders (106 and 107) which make an optical element (for example, 106) movable in the direction of an optical axis, chromatic aberration compensation and spherical aberration compensation can be freely performed in accordance with conditions such as a light source wavelength, a magnification, a substrate thickness, and a temperature in information recording and/or reproducing on each optical disk. Thus an objective lens 109 is easily designed and manufactured. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
