A multicolor projection display using nematic-cholesteric liquid crystal

A multicolor projection display with a bright screen and high information content using nematic-cholesteric (NC) liquid crystals is discussed. Through investigation of light scattering in the focal-conic state of the NC liquid-crystal layer, it was found that the transmittance depends on the light wavelength due to diffraction scattering and that the color of light transmitted through the layer can be controlled by the birefringence and the thickness of the liquid-crystal layer. A 640×400 pixel multicolor projection display was fabricated using a two-layered liquid-crystal panel, each layer passing green and red light under the focal-conic state. The Munsell chroma value was six for both the projected colors. The projector provides excellent white and black because of the high transmittance of the nematic state and the subtractive mixture of complementary colors