The Performance of Dichroic Displays for Automotive Instrument Panel Use

Conventional liquid crystal displays, which are based upon twisted nematic materials, suffer from several problems: their polarizers limit their viewing angles and make them sensitive to humidity, they are fairly slow, and they do not lend themselves readily to multicolor displays. A new dichroic dye LCD from Integrated Display Systems, Inc., overcomes these problems because it operates on an absorption, rather than a polarization, principle. The new display essentially, is a light valve. It is opaque in the off state, appearing black when exposed to incident light. With an applied field, the LCD becomes transmitting, showing the color (or colors) of the reflector. The operation of the dichroic dye display involves a phase change from the cholesteric state, in which the dye absorbs light, to the nonabsorbing nematic state. The paper will discuss in detail the performance of dichroic displays with respect to automotive requirements.