Display apparatus and method for forming hologram suitable for the display apparatus

摘要

A dichroic or trichromatic transparent display apparatus through which a background view is seen comprises a transparent substrate, a hologram formed on a rear face of the transparent substrate, a dispersion liquid crystal device disposed in front of a front face of the transparent substrate, a light source disposed for facing a side face of the transparent substrate and a transparent layer at least partially provided between the transparent substrate and the hologram. The refractive index of the transparent layer is smaller than that of the transparent substrate. A first light emitted from the light source and having a first wavelength is totally reflected by the boundary face between the transparent substrate and the transparent layer so that the first light moves to and is diffracted by a first region of the hologram where the transparent layer is not provided. A second light having a second wavelength is diffracted by a second region of the hologram where the transparent layer is provided. Thus, at least dichroic display is realized.