Patent ID: 8369015

Claim:
An optical element comprising: an optical anisotropic medium; a first optical isotropic medium; and a second optical isotropic medium, wherein the optical anisotropic medium is disposed between the first and second optical isotropic media, wherein the optical anisotropic medium consists of one material, wherein a difference between a minimum refractive index n l and a maximum refractive index n h of the optical anisotropic medium at a wavelength between 500 nm and 600 nm is at least 0.1, and wherein, when a refractive index of the first optical isotropic medium at the wavelength is defined as n t1 , a refractive index of the second optical isotropic medium at the wavelength is defined as n t2 , and a thickness of the optical anisotropic medium is defined as d, the optical element satisfies the following conditions: ( n t1 −n l )·( n t1 −n h )≦0, ( n t2 −n l )·( n t2 −n h )≧0, and 362 nm≦d≦890 nm.