| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a liquid crystal element and an optical system for an optical pickup, the element and the system nearly continuously correcting large aberration. <P>SOLUTION: The liquid crystal element 14 includes a first transparent electrode layer 146 and a second transparent electrode layer 147 which drive a first liquid crystal layer 144. In the liquid crystal element 14, the first transparent electrode layer 146 applies a voltage to the first liquid crystal layer 144 in such a way that the first liquid crystal layer 144 has a section to impart retardation nearly periodically varying along a radial direction of a laser beam to the laser beam passing through the liquid crystal element 14 in the range of -hλ to +hλ (h is an integer satisfying h≥1, λ is a design wavelength), and to impart retardation of hλ to the laser beam passing through a transparent electrode adjacent to the first transparent electrode layer 146, and the second transparent electrode layer 147 applies a voltage to the first liquid crystal layer 144 in such a way that the first liquid crystal layer 144 imparts retardation nearly continuously varying along a radial direction of the laser beam to the laser beam passing through the liquid crystal element 14. <P>COPYRIGHT: (C)2010,JPO&INPIT |
