| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical head device which has reduced aberration and is small-sized and light-weighted, and which is compatible with different kinds of optical disks. <P>SOLUTION: A liquid crystal element mounted in an optical head device is constituted so that a liquid crystal is sandwiched between two transparent substrates. At the periphery of an area decided by a numerical aperture to outgoing light having a maximum wavelength between at least two usable wavelength on a surface of one transparent substrate, the element is formed so that concentric electrodes about an optical axis are formed and a wave aberration of the outgoing light having the maximum wave length is compensated. The liquid crystal device 10 is located in an optical path between a synthesis prism 7 of the optical head device, and an optical recording medium 5. <P>COPYRIGHT: (C)2004,JPO |
