Abstract: In a liquid crystal display, and more particularly, in a thin film transistor matrix addressed liquid crystal display, a method and means are provided for assuring the presence of a constant RMS voltage waveform on the data lines. This eliminates uncertainty in the voltage levels on a pixel element caused by parasitic capacitance effects between the data lines and the pixel electrodes. The present invention is also particularly applicable to both binary level and gray scale level devices. Means for carrying out the present method are illustrated in both analog and digital form.

Abstract: A thin film FET switching element, particularly useful in liquid crystal displays, employs a set of special materials to ensure compatibility with the indium tin oxide of a pixel electrode layer used as transparent conductive material in liquid crystal display devices. These materials include the use of titanium as a gate electrode material and the use of aluminum as a material to enhance electrical contact between source and drain pads and an underlying layer of amorphous silicon. The apparatus and process of the present invention provide enhanced fabrication yield and device reliability.

Abstract: Redundancy is provided in the data and gate lines of the liquid crystal display device for improved reliability and greater fabrication yield. The data lines in particular are preferably fabricated in a multilayer structure with two conductive layers sandwiching a narrow insulating strip. The presence of the insulating strip permits the upper conductive line to be formed without step jumps which can exhibit a tendency for poor electrical connection. The upper and lower conductive layers of the data line are in contact for the length of the lower data line, contact being made on either side of the narrower insulating strip. Similar redundancy, without the necessity of providing an intermediary insulating layer is also provided for the gate lines. The redundancy provided in the present invention is particularly suitable for fabrication methods employed in thin film FET driven LCD devices.

Abstract: An enhanced manufacturing yield of a high resolution, high accuracy information conversion device, such as a liquid crystal display, is attained through incorporation into the device of auxiliary address lines. Such auxiliary address lines are used to provide electrical communication with portions of main address lines that, due to the presence of electrical open circuits, would otherwise be electrically isolated. Each auxiliary address line crosses over multiple main address lines and can be electrically shorted to any such main address line to provide electrical communication therewith. The ratio of auxiliary address lines to main address lines is accordingly low, such as 1:10 or less, for example.

Abstract: Information is written into a matrix-addressed electroscopic display by means of a writing stylus having a magnetic tip, utilized to attract a moveable plate electrode in a selected one of the display matrix cells. A capacitance detector, connected to sequential ones of the column electrodes of the display via a first multiplexer and to sequential ones of the row electrodes of the matrix display via a second multiplexer, detects the change in cell interelectrode capacitance caused by movement of the moveable plate electrode. The capacitance of each display cell is compared with the data for the output state commanded for that cell, to recognize input data sites programmed by the magnetic writing stylus.

Abstract: An electroscopic display device includes a plurality of small, moveable plates which are each electrostatically deflectable from a resting position, at a rear surface of a display cell, to a display position adjacent to a viewable front surface of the cell. A portion of the electrode structure remains fixedly adjacent to the cell rear surface and a second electrode is positioned fixedly adjacent to the front surface. Light entering through the rear of the cell is internally reflected before exiting through the front surface, only if the moveable electrode portion has been electrostatically attracted to the fixed front electrode. The display device is fabricated by masking and subsequent etching of a plurality of layers formed upon the surface of a display substrate, to provide the moveable electrode, spring and fixed electrode as an integrated structure.

Abstract: An electroscopic display cell in which stationary and moveable plate electrodes are fabricated upon a single substrate to provide a display with operating characteristics independent of cell thickness. The stationary electrodes are overcoated with a dielectric layer and a conductive plate electrode structure is thereafter fabricated upon the dielectric layer. Each electrode plate has a rest position determined by support members affixed to the dielectric layer and independent of the spacing between the single substrate and another substrate, which serves only to contain a display fluid.

Abstract: An improved varistor-controlled multiplexed liquid crystal display of the type having columns of front electrodes and rows of rear electrodes connected in series with combinations of varistor elements and electrical capacitances, has a capacitance of increased magnitude formed in parallel with the capacitance of the liquid crystal layer in each of the multiplicity of the display cells, for reducing capacitive crosstalk between an addressed and unaddressed cell elements of the display. The increased capacitance is provided by auxiliary data electrodes positioned below, and spaced by a thin film dielectric layer from, the reflective rear cell row electrodes of the display, and spaced from the varistor member by at least one thick film dielectric layer. A pair of thick film layers may support the row scan electrodes therebetween, or the scan electrodes may be formed between a single layer and the varistor surface.

Abstract: Liquid crystal displays allowing high order multiplexing, typically with a multiplexing order N of about 1,000, utilize a thin sheet of a varistor material to provide a high degree of non-linearity in the optical response of the display with respect to the multiplexed driving voltage for each cell of the display.

Abstract: A device for illuminating, as well as enhancing contrast of, reflective dichroic liquid crystal displays utilizes a polarizing member extending across the thickness of a wedge illuminator. The light emitted from the wedge illuminator is polarized in a single direction, perpendicular to the elongated direction of the dichroic dye molecules in the light-transmitting areas of the display cell.

Abstract: The molecules in a twisted nematic liquid crystal are, in general, skewed relative to the optical axis of the cell (the perpendicular to the plane surfaces defining the boundaries of the crystal cell), and their birefringent effect on plane polarized light varies asymmetrically for such light making varying angles with the optical axis of the cell. When the cell is positioned between crossed polarizers and the cell is energized so that light is supposed to be completely extinguished, some rays are nevertheless transmitted so that the transmitted intensities at different viewing angles vary. To avoid this resulting variation of intensity with viewing angle, the cell is illuminated from behind with collimated light (i.e., all rays parallel to the optical axis of the cell) so that all rays "see" the average molecular director in the same way; a solid catadroptric element is utilized to both collimate the light and achieve essentially constant luminous flux intensity upon the display.

Abstract: A laminated capacitive touch-pad having a thin film touch-plate electrode deposited upon a first (exterior) surface of a first, relatively thin dielectric layer and having spaced transmitter and receiver electrodes deposited upon a second surface of the first layer within the outline of and opposite to the touch electrode, with a relatively thick backing layer of dielectric material laminated upon the second surface to provide a total thickness, as measured between the furthest opposed surfaces of the first and second layers, as required for high voltage insulation purposes and to provide additional impact strength. The touch, transmitter and receiver electrodes may be of thin film construction.

Abstract: An optically pumped crystalline laser that includes a small single crystal section of a polygonal cylinder; the dimensions of the crystal section and the index of refraction of the crystal and the medium surrounding the crystal are such that there is formed a dielectric resonator that is totally reflective for a small number of modes. The material of which the crystal section is composed is one that is capable of being made optically thick in thin sections. The resonator is optically pumped and the lasing radiation therein is coupled to an optical element that is placed in close proximity thereto by virtue of an evanescent field that arises from the lasing action in the resonator.