Liquid crystal panel and projection display with use of liquid crystal

Abstract

In an optical system phase device such as .lambda./2 plate or a .lambda./4 plate is used to convert S polarization to P polarization and vice versa. In the projection display, a white light emitted from a light source is separated by a color separation optical system, including dichroic mirrors or a dichroic prism, into three primary colors which are modulated by optical modulation elements. Then, the modulated lights are synthesized by a color synthesis optical system and projected by a projection element onto a screen. When appropriate plates are inserted appropriately in the optical system of the projection display, the conversion between S and P polarization occurs and an optical bandwidth becomes narrow, and color purity can be improved. A thick transparent plate is preferably adhered to the optical modulation element. A light absorption film is applied to an ineffective plane of the transparent plate. The phase device is preferably inserted between an optical modulation element and a transparent plate or the like to improve contrast. The invention can be applied to liquid crystal panels such as liquid crystal/resin display panels, light beam writing type display panel or micro mirror display panel. Preferably, the phase device is set to be rotatable so as to adjust contrast appropriately.