| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a liquid crystal element and an optical system for optical pickup in which a response property and productivity are improved, while deterioration of spot performance is suppressed. <P>SOLUTION: The liquid crystal element includes a first transparent electrode layer 146 and a second transparent electrode layer 147 which drive a first liquid crystal layer 144. The first transparent electrode layer 146 applies voltage to the first liquid crystal layer 144 such 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 nearly hλ to the laser beam passing through a transparent electrode adjacent to the first transparent electrode layer 146, and the liquid crystal element 14 includes a light shielding film 20 reducing light quantity of luminous flux transmitting a part imparting retardation being nearly hλ. <P>COPYRIGHT: (C)2010,JPO&INPIT |
