| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a polarization conversion separating element and a surface light source device using the element in which one of the polarization components among two polarization components having mutually orthogonal polarization directions is efficiently converted to the polarization component that is same as the other polarization component and the polarized light beams are emitted to a prescribed direction with high transmissivity. <P>SOLUTION: A polarization conversion separating element 6 is provided with a film-like substrate 6a, a thin film laminated body 6b in which a low refractive index thin film 6b1 whose refractive index is equal to or greater than 0.05 and a high refractive index thin film 6b2 are alternatively laminated and an optically active layer 6c which is arranged adjacent to the thin film laminated body 6b. Thickness of each of the thin films 6b1 and 6b2 is in the range of (0.7 to 1.3)λ/4, wherein λ is the wavelength of the light beams within the thin films. The surface light source device is obtained by combining the polarization conversion separating element 6 with a primary light source 2, a plate shaped light guiding body 4 having a light emitting surface 42 consisting of a rough surface whose average inclined angle is 0.5 to 20 degrees and a prism sheet 8 in which a plurality of prism columns are arranged in a mutually parallel manner. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
