| 摘要 |
PROBLEM TO BE SOLVED: To make reflected and diffracted light at a wide wavelength width approximate to white color possible to be generated by specifying the intervals of the wavelengths before and after the diffraction efficiency is halved with respect to the wavelength, at which the diffraction efficiency is maximized, to a specific value or above. SOLUTION: The liquid crystal panel 2 side of the hologram reflection plate 1 is a volume phase reflection type hologram having angle selectivity and emits only a light incident at the same angle as the angle of reference light at the time of hologram photographing as the reflected and diffracted light 4 to the same angle as the angle of the object light at the time of photographing. The incident light which does not match with the angle selectivity of the hologram passes the hologram as it is without receiving the diffraction, is reflected by the reflection layer existing on the rear surface of the halogen, passes the liquid crystal panel again, and arrives as pattern display light at the observer's eyes. The optical characteristics are so set that the central wavelength of the reflected and diffracted light 4 from the hologram exists at a point of 50 nm±30 nm and that the intervals of the wavelengths before and after the diffraction efficiency is halved with respect to the wavelength, at which the diffraction efficiency is maximized. |
