Patent ID: 8345189

Claim:
A diffractive display device, comprising: a first substrate; a second substrate; first illuminating means for entering light through a first side surface of the first and second substrates; second illuminating means for entering light through a second side surface of the first and second substrates from a direction different from the light from the first illuminating means; and an optical material layer provided between the first and second substrates, the optical material layer comprising: a first portion provided to diffract the light from the first illuminating means to emit the light through an output surface of the first substrate, the first portion comprising: a first diffraction display section in which first refractive index isotropic regions and first refractive index anisotropic regions are inclined with respect to the output surface of the first substrate to diffract only the light from the first illuminating means; and a second portion provided to diffract the light from the second illuminating means to emit the light through the output surface of the first substrate, the second portion comprising: a second diffraction display section in which second refractive index isotropic regions and second refractive index anisotropic regions are inclined with respect to the output surface of the first substrate to diffract only the light from the second illuminating means.