| 摘要 |
PROBLEM TO BE SOLVED: To obtain a light display image with a wide wavelength range and a wide observation angle. SOLUTION: The hologram scattering plate 3 is composed of a transmission hologram layer and a back layer; and (a) 1st one in Figure is formed by providing only a transmission type hologram layer 1 with a diffusing function and a diffracting function and has a specular reflecting layer as the back layer 2; (b) 2nd one is formed by providing a transmission type hologram layer 1 with a diffracting function and a back layer 2 with a diffuse reflecting function, and (c) 3rd one is formed by providing a transmission type hologram layer 1 with a diffusing function and a diffracting function and a back layer 2 with a diffuse reflecting function. A transmission hologram 1 can limit a diffraction and a scattering direction and a back layer 2 can increase the reflection factor in a wide wavelength range, and thereby, diffused light with high luminance can be obtained in a wide wavelength range and a wide observation angle. |
