| 摘要 |
PROBLEM TO BE SOLVED: To generate a uniform phase difference regardless of wavelength in optical phase difference of all wavelength of visual light, by specifying the wavelength dispersion value of a phase difference plate of such structure that a plural kinds of double reflective media different in the wavelength dispersion value of a double refractive index are laminated in the orthogonally crossing state of respective lag axes. SOLUTION: In the phase difference plate formed by laminating double refractive media 10, 20 different in the wavelength dispersion valueα[α=▵n (450nm)/▵n (650nm)] of a double refractive index▵n, in the orthogonal state of lag axes 11, 21, the wavelength dispersion valueαof this phase difference plate is made smaller than 1. When white linear polarized light enters this phase difference plate, optical phase difference generated from material with a characteristic of small wavelength dispersibility is cancelled by phase difference generated by material with a characteristic of large wavelength dispensability, and the cancelled phase difference quantity is larger in the phase difference generated in shorter wavelength. Longer the wavelength, phase difference amount shows the tendency of more monotoneous increase, and the polarized light incoming as white light also generates uniform phase difference in a visible light area so as to be obtained as white polarized light.
|
