| 摘要 |
PURPOSE:To improve the contrast, to make the picture bright, and to widen the visual angle of an accumulation type liquid crystal display element, by adding a two-color blackish coloring agent to a cholestericnematic phase transfer type liquid crystal material showing a positive dielectric constant anisotropy. CONSTITUTION:When a liquid crystal panel is prepared by putting a liquid crystal material between two glass base plates 1 and 2 and an intense voltage is applied across the liquid crystal panel, the liquid crystal material becomes a transparent (H) condition. Under the H condition, all the liquid crystal molecules 3 and dye molecules 4 become perpendicular to the direction of the electric field, namely, perpendicular to the base plates 1 and 2 and incident light is transmitted without absorption. Therefore, if a white background paper is put on the back of the base plate, the H condition becomes white. When the applying voltage is made to zero thereafter, the liquid crystal molecules 3 become to have a spiral structure and the dye molecules 4 are dispersed between the steps of the liquid crystal molecules 3 in random directions and a cloudy (F) condition is obtained. Under the F condition, dye molecules which absorb incident light are produced and, as a result, the white background paper cannot be seen and becomes black. Therefore, the contrast can be improved, picture can be made bright, and visual field can be widened in such an inexpensive way.
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