Patent ID: 7446848

Claim:
An optical element, comprising: at least two laminated circular-polarization-type-reflection polarizers (a) whose wavelength bands for selective reflection of polarized light overlap one another, and a retardation layer (b) which is placed between the circular-polarization-type-reflection polarizers (a) and has a front retardation of substantially zero (in the normal direction) and a retardation of at least λ/8 with respect to incident light inclined by 30° relative to the normal direction, wherein the at least two circular-polarization-type-reflection polarizers (a) each have a side capable of selectively reflecting a relatively short wavelength in the wavelength bands for selective reflection, and the sides of said at least two circular-polarization-type-reflection polarizers (a) capable of selectively reflecting the relatively short wavelength are arranged opposite to each other.