| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a wideband 1/2 wave plate functioning as a 1/2 wave plate for incident light having a plurality of wavelengths for use in recording and reproduction of optical information, wherein a material to be used is not limited to a material having small wavelength dispersion, and to provide an optical head device. <P>SOLUTION: The wideband 1/2 wave plate includes: transparent substrates 11a, 11b; alignment films 13a, 13b formed on substrate surfaces at one side of the transparent substrates 11a, 11b; anisotropic medium layers 14a, 14b comprising a medium having optical anisotropy; seal members 15a, 15b; and an adhesive 16. The anisotropic medium layers 14a, 14b are laminated so that fast axes form a mutual prescribed fast axis crossing angle. The anisotropic medium layer functions as the 1/2 wave plate at least an intermediate retardation wavelength. <P>COPYRIGHT: (C)2010,JPO&INPIT |
