| 摘要 |
PROBLEM TO BE SOLVED: To provide a polarized beam splitter made small-sized and thin while attaining high diffraction efficiency over a wide wavelength range to improve the use efficiency of light by utilizing a diffraction optical element, and to provide a polarization conversion element and an image display device. SOLUTION: The polarized beam splitter has a first optical element component 11 comprising an isotropic optical material and having a first diffraction optical surface, and a second optical element component 12 adjacent to the first optical element component 11 and comprising a birefringent optical material and having a second diffraction optical surface, wherein when the refractive index of the isotropic optical material is expressed by N1, the refractive index of the birefringent optical material to an ordinary beam is expressed by No and the refractive index of that to an extraordinary beam is expressed by Ne and the refractive index nearer to the refractive index N1 in the refractive indexes No and Ne is expressed by N2n, a condition of the relation of ¾N1-N2n¾<0.01 and ¾Ne-No¾>0.05 is satisfied. COPYRIGHT: (C)2010,JPO&INPIT
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