Edge-illuminated liquid crystal display devices

#1. Field of the Invention

#The present invention generally relates to the field of electro-optical liquid crystal devices, and more particularly to a high contrast liquid crystal display panel.

#2. Description of the Related Art

#FIG. 1 is a diagram illustrating an edge-illuminated liquid crystal device of the present invention configured to operate in a transmission mode;

#FIG. 2 illustrates the present invention configured to operate in a reflection or display image source mode;

#FIG. 3 is a diagram illustrating an edge-illuminated liquid crystal device of the present invention, in which the device acts as either a light pipe or a light-emitting panel; and

#Referring now to FIG. 1 of the drawing, a liquid crystal display device embodying the present invention is generally designated as 10 and includes a display panel 12 having a polymer dispersed liquid crystal (PDLC) display cell 14. The cell 14 includes a PDLC film 16 which may be produced by the process described in the above-referenced patents U.S. Pat. Nos. 4,688,900 and 4,728,547 or any other suitable process. The cell 14 further has electrode layers 18 and 20 formed of, for example, indium tin oxide (ITO), on the opposite surfaces of the film 16. The cell 14 is schematically illustrated as having an off-segment 22 and on-segments 24 and 26. No electric field is applied across the cell 14 in the off-segment 22, and an electric field from a voltage source 28 is applied across the cell 14 by means of the electrode layers 18 and 20 in the on-segments 24 and 26.

#The display panel 12 further includes front and back transparent face plates 30 and 32 respectively which sandwich the liquid crystal cell 14 therebetween. The face plates 30 and 32 may be formed of glass, plastic, plexiglass, or any other suitable material, with the thicknesses thereof selected to produce optimal results.

#The embodiment of the invention illustrated in FIG. 1 is designed to operate in a transmission, or direct-view mode, and includes a light absorbing material 33 provided behind the back face plate 32. The material 33 may be black paint applied to the surface of the face plate 32, or a separate black sheet or plate which is maintained in contact with the plate 32 or spaced at a slight distance behind the plate 32.