High Order Parameter Dyes for Liquid Crystal Displays
Original Publication Date: 1980-Oct-01
Included in the Prior Art Database: 2005-Feb-13
A liquid crystal display consisting of a dye dissolved in a nematic host has several advantages over the twisted nematic display commonly used, namely, the viewability is much less dependent on cell thickness and viewing angle. It also has the advantage of producing colored images when that is desired. The following stringent requirements are placed on the dye to be used in this manner: 1. It must be sufficiently soluble in the liquid crystal. 2. Its order parameter in the liquid crystal must be high, i.e., it must assume good alignment with its host. 3. The extinction coefficient in the visible spectrum must be large. 4. It must be both photo and chemically stable. 5. It must be non-ionic so that no current is passed when it is put in an electric field.