Transflective liquid crystal display with integral heating unit and temperature sensor

DETAILED DESCRIPTION OF THE INVENTION FIG.
1 shows a transflective liquid crystal display which includes a liquid crystal cell 11 having a front substrate 12 and a rear substrate 14 of a substantially transparent material, such as glass or the like.
Deposited on the interior surfaces of the front and rear substrates are optically transmissive, conductive electrodes segments 15 and 16 which define the cell display elements.
As is well known in the art, electrodes 15 and 16 may be fabricated of indium oxide, tin oxide, indium tin oxide (with the latter being preferred) and the like.
The front and rear plates of the cell are sealed by means of the sealing plug elements 17 and 18 to form a chamber which contains liquid crystal solution 19.
Liquid crystal solution 19 is preferably one in which a dichroic dye or combination of dyes is a guest in a liquid crystal host material of the cholesteric type.
The solution also includes an optically active material whereby the host liquid crystal molecules assumes a helical orientation with the molecules substantially parallel and twisted with respect to the cell walls in the absence of an electric field.
Electrodes 15 and 16 are connected through suitable leads and a switching means, not shown, to a voltage source.
When the switching means opens the liquid crystal material molecules assume their normal helical orientation.
The long axes of the dichroic molecules are aligned helically and parallel to the substrate surface so that light passing through the cell is essentially absorbed by the dye molecules.
When power is applied to the electrodes segments 15 and 16, an electric field is established and the liquid crystal molecules between those electrodes assume a homeotropic order with their long axes substantially perpendicular the plane of the front and rear electrode; i.
e.
, the helix unwinds.
The dye molecules also align themselves in a homeotropic order with their long axis perpendicular to the plane of the electrodes and in this orientation permit light to pass