Patent ID: 7352678
Filing Date: 2008-04-01
Classification: G02B,G11B

Abstract:
1. A laminated wave plate, comprising a first wave plate with a phase difference α and a second wave plate with a phase difference β both with respect to monochromatic light having a wavelength λ, said wave plates being laminated together in such a way that directions of optical axes of said wave plates intersect each other, so that the laminated wave plate, as a whole, functions as a quarter-wave plate with respect to lights having two or more different wavelengths, wherein: said first wave plate satisfies the following formula: said second wave plate satisfies the following formula: a relationship between said α and β satisfies the following formula: said α and β respectively satisfy the following formulas: said optical axes of said first and second wave plates cross each other at an angle not equal to 90°.