Abstract: The present application relates to a turn-off power semiconductor device having a wafer with an active region and a termination region surrounding the active region, a rubber ring as an edge passivation for the wafer and a gate ring placed on a ring-shaped gate contact on the termination region for contacting the gate electrodes of a thyristor cell formed in the active region of the wafer. In the turn-off power semiconductor device, the outer circumferential surface of the gate ring is in contact with the rubber ring to define the inner border of the rubber ring. The area consumed by the ring-shaped gate contact on the termination or edge region can be minimized. The upper surface of the gate ring and the upper surface of the rubber ring form a continuous surface extending in a plane parallel to the first main side of the wafer.

Abstract: The present application relates to a turn-off power semiconductor device having a wafer with an active region and a termination region surrounding the active region, a rubber ring as an edge passivation for the wafer and a gate ring placed on a ring-shaped gate contact on the termination region for contacting the gate electrodes of a thyristor cell formed in the active region of the wafer. In the turn-off power semiconductor device, the outer circumferential surface of the gate ring is in contact with the rubber ring to define the inner border of the rubber ring. The area consumed by the ring-shaped gate contact on the termination or edge region can be minimized. The upper surface of the gate ring and the upper surface of the rubber ring form a continuous surface extending in a plane parallel to the first main side of the wafer.

Abstract: An alignment layer for a liquid crystal display consists at least substantially of a polyphenylene polymer wherein at least 80% of the said polyphenylene polymer is composed of aromatic phenylene rings. The alignment layer is capable of providing a homogeneous alignment of liquid crystal molecules disposed adjacent thereto with a high tilt bias angle.

Abstract: A process and apparatus for the production of an orientation layer on a plane surface of a plate, and a liquid crystal substrate plate produced thereby. By the process of evaporation from a source, orientation layers are deposited on the plane surfaces of a plurality of liquid crystal substrate plates used for application in liquid crystal displays. To obtain a uniform orientation of the optic axis of the liquid crystal with regard to the azimuthal alignment by means of the preferred direction caused by the orientation layer on the surface, the plates are moved in a direction crosswise to the evaporation direction during the evaporation process. The field of the particle stream emanating from the source is limited by an aperture in an aperture screen which is introduced between the source and the plates. The plates pass completely through the particle stream during the course of the evaporation operation. The finished plates include an approximately 5 nm thick orientation layer.

Abstract: A liquid crystal display based on the bistability effect, wherein the distance between the support plates is smaller than 10 .mu.m and the total twist of the liquid crystal is between 180.degree. and 360.degree., preferably about 270.degree.. Over the entire viewing area of the display, randomly distributed spacers are provided. Because of these measures, the range of the bistable action is so narrowed that the display can be driven with operating voltages outside this range, using conventional multiplexing techniques. A high degree of multiplexing with short switching times and excellent contrast is obtained. The range of viewing angles is very large and independent of the direction of illumination.

Abstract: A liquid crystal display based on the bistability effect, wherein the distance between the support plates is smaller than 10 .mu.m and the total twist of the liquid crystal is between 180.degree. and 360.degree., preferably about 270.degree.. Over the entire viewing area of the display, randomly distributed spacers are provided. Because of these measures, the range of the bistable action is so narrowed that the display can be driven with operating voltages outside this range, using conventional multiplexing techniques. A high degree of multiplexing with short switching times and excellent contrast is obtained. The range of viewing angles is very large and independent of the direction of illumination.

Abstract: A liquid crystal display cell including a liquid crystal layer contained between two plane-parallel support plates provided with electrode layers on their mutually inward facing surfaces as well as a border. The support plates are held apart within a predetermined separation range by means of spacers. Those spacers distributed in the border are electrically conductive and serve as contact bridges between through-contact points on the support plates. Rubber-like elastic particles, e.g. from a silicone elastomer, are used as spacers to prevent low pressure bubbles in the liquid crystal layer at temperatures of -30.degree. C. as well as to prevent loss of contact between the through-contact points. The rubber-like elastic particles, between the through-contact points are electrically conductive.

Abstract: An addressing method for a multiplexable, bistable liquid crystal display wherein a first driving voltage which is larger than a first limiting voltage is applied to the selected display elements and a second driving voltage which is smaller than a second limiting voltage is applied to the non-selected display elements. For the first driving voltage only a first optical state is stable, and for the second driving voltage only a second optical state is stable. All the display elements are simultaneously switched on the display by means of a single writing voltage pulse. By this means a high-contrast, constant and immediate display is achieved over the entire active area. Row-at-a-time writing is also possible. Moreover, a liquid crystal display is introduced which is based upon the bistability effect and which employs a guest-host liquid crystal containing a chiral additive. The layer thickness of the liquid crystal is less than 10 .mu.