| 摘要 |
<p>1484618 Controlling light PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 27 Nov 1974 [30 Nov 1973] 51389/74 Heading G2F Each support plate of a liquid crystal display cell is provided with a layer of material which induces molecular alignment in the adjacent liquid crystal material, the layer being produced by disposing the plate in an atmosphere comprising an alkoxide, e.g. of Si, Ti, Al or B and an auxiliary gas, in the presence of an electric discharge. For homotropic orientation, a tetra-alkoxide is used, whereas trialkoxides, particularly if the plate is also grooved, provide parallel (homogeneous) orientation. The aligning layer appears to be a polymeric material, and the distance between the arode (support plate) and cathode should be at least 150mm to prevent oxide formation due to ion and electron bombardment. The auxiliary gas may be argon, nitrogen, oxygen or air. As particularly described, a metal oxide electrode layer and edge contact layers of Au and Ni are deposited on the plate by cathode sputtering, and are covered with photo-sensitive lacquer, which is exposed and etched. The edge contact layers are then etched chemically, and the electrode layer undergoes argon ion etching. The remaining portions of photo-sensitive lacquer are removed by oxygen ion bombardment which gives a clear surface for deposition of the aligning layer at reduced pressure. If grooved plates are required, either the plate or the oxide electrode layer may be grooved by a photo-resist and ion etching process. Grooves in the electrode layer should not extend entirely therethrough. The grooves preferably have a spacing and width of 1Á and a depth of up to 0À30Á, and provide an undulating profile rather than one which is stepped. In the assembled device, the groove direction and hence the molecular alignment direction on each plate may be the same or different.</p> |
