| 摘要 |
PROBLEM TO BE SOLVED: To provide both selectively reflecting characteristic and circularly polarizing characteristic to reveal an optical effect having both the characteristics in a good balance regardless of the surface or reverse side of a polarizing diffraction element by constituting the polarizing diffraction element from a cholesteric liquid crystal layer partially having an area showing diffractivity, and setting the number of spiral turns in the cholesteric alignment of this liquid crystal layer in a specified range. SOLUTION: This polarizing diffraction element is formed of at least a cholesteric liquid crystal layer partially having an area showing diffractivity. The area showing diffractivity means the area causing the effect such that the light transmitted or reflected by this area creeps into a part geometrically forming a shadow. In this cholesteric liquid crystal, the number of spiral turns in the cholesteric alignment is within the range of 2-20. When the winding is less than two, the selective reflectivity or circular polarizability by cholesteric alignment might be deteriorated. When the number of turns exceeds 20, the selective reflectivity or circularly polarizability might appear too conspicuously.
|
