Abstract: A method of addressing a bistable liquid crystal material having incremental reflectance properties disposed between opposed substrates is disclosed. One substrate has a first plurality of electrodes deposited thereon facing a second substrate which has a second plurality of electrodes disposed thereon. The intersection of the first and second plurality of electrodes forms a plurality of pixels. The addressing method includes applying a predetermined number of pulses to the first plurality of electrodes, and applying a like number of the predetermined number of pulses to the second plurality of electrodes. Each of the predetermined number of pulses has a different frequency, wherein the predetermined number of pulses are applied in a set time period.

Abstract: A reflective cholesteric display that may be viewed under a wide range of ambient lighting conditions, ranging from complete darkness to bright sunlight. The display includes a chiral nematic liquid crystal material located between first and second substrates, an ambidextrous or bi-directional circular polarizer, a partial mirror, also referred to as a transflector, and a light source. The liquid crystal material includes focal conic and planar textures that are stable in the absence of an electric field. The ambidextrous circular polarizer is located adjacent to one of the substrates that constrain the liquid crystal material. The chiral nematic liquid crystal display may be operated in both a transmissive mode and a reflective mode.

Abstract: Reflective chiral nematic liquid crystal material is disposed between a first set of electrodes and a second set of electrodes arranged on opposed sides of the material to define a collection of pixels. Fast updating dynamic drive scheme is implemented by selectively applying an electric field via the electrodes through the pixels in four phases of energization: preparation, selection, evolution, and non-select. Each phase is made up of a series of voltages having varying amplitudes. The voltage waveform is for each phase controlled based on the selection phase to achieve image uniformity. For example, the evolution voltages that are established across adjacent pixels having the same final state have initial amplitudes that are equal for both pixels to increase image uniformity.

Abstract: Reflective chiral nematic liquid crystal material is disposed between a first set of electrodes and a second set of electrodes arranged on opposed sides of the material to define a collection of pixels. Fast updating dynamic drive scheme is implemented by selectively applying an electric field via the electrodes through the pixels in four phases of energization: preparation, selection, evolution, and non-select. Each phase is made up of a series of voltages having varying amplitudes. The voltage waveform is for each phase controlled based on the selection phase to achieve image uniformity. For example, the evolution voltages that are established across adjacent pixels having the same final state have initial amplitudes that are equal for both pixels to increase image uniformity.

Abstract: A method of addressing a bistable liquid crystal material having incremental reflectance properties disposed between opposed substrates is disclosed. One substrate has a first plurality of electrodes deposited thereon facing a second substrate which has a second plurality of electrodes disposed thereon. The intersection of the first and second plurality of electrodes forms a plurality of pixels. The addressing method includes applying a predetermined number of pulses to the first plurality of electrodes, and applying a like number of the predetermined number of pulses to the second plurality of electrodes. Each of the predetermined number of pulses has a different frequency, wherein the predetermined number of pulses are applied in a set time period.

Abstract: The present invention is directed to a cholesteric liquid crystal display that includes a homogeneous alignment surface effective to provide increased brightness, low focal conic reflectance and/or reflected light that is to a significant degree circularly polarized. The homogeneous alignment surface substantially homogeneously aligns the liquid crystal director adjacent thereto. The homogeneous alignment surface may be disposed on one or both sides of a cell of the display. In the case of a cell in which the homogeneous alignment surface is disposed on only one side, the substrate with the inhomogeneous alignment surface may be upstream or downstream of the substrate with the homogeneous alignment surface relative to a direction of incident light. Also included especially in the case of a cell that has the homogeneous alignment surface on both sides is the use of a polarizer to provide very good brightness and low focal conic reflectance.

Abstract: A liquid crystal material for a display device includes a liquid crystal material comprising first chiral nematic liquid crystal component and a second component that exhibits no liquid crystalline phase. The second component is present in an amount not greater than 5% by weight based upon the total weight of the liquid crystal display material and is effective to avoid image sticking of the display device when in use. The liquid crystal material has positive dielectric anisotropy. The second component may have a molecular weight not exceeding 205 grams/mole.

Abstract: A reflective cholesteric display that may be viewed under a wide range of ambient lighting conditions, ranging from complete darkness to bright sunlight. The display includes a chiral nematic liquid crystal material located between first and second substrates, an ambidextrous or bi-directional circular polarizer, a partial mirror, also referred to as a transflector, and a light source. The liquid crystal material includes focal conic and planar textures that are stable in the absence of an electric field. The ambidextrous circular polarizer is located adjacent to one of the substrates that constrain the liquid crystal material. The chiral nematic liquid crystal display may be operated in both a transmissive mode and a reflective mode.

Abstract: A flat-panel liquid crystal display having unipolar drive circuitry. The display includes a flat sheet of bistable chiral nematic liquid crystal material activated by a drive circuit that individually controls the display state of multiple picture elements at a refresh rate 1000 scan lines per second. The driver circuitry activates the liquid crystal domains into homeotropic states over a relatively long activation period and then, during a short (˜1 msec.) selection period, either keeps the domains in a homeotropic state or initiate a transition to the transient twisted planar state. The drivers then activate the domains in an evolution phase to provide either focal conic or twisted planar end states across the two-dimensional array of picture elements. The drive circuitry includes a plurality of unipolar display drivers which generate substantially square wave, unipolar waveforms which are applied to row and column electro segments.

Abstract: A liquid crystal material for a display device includes a first chiral nematic liquid crystal component and a second component that exhibits no liquid crystalline phase at any temperature. The second component is present in an amount effective to reduce the bulk viscosity of the liquid crystal material by at least about 26% at room temperature or is present in an amount of at least about 5% by weight based upon the total weight of the liquid crystal material. The liquid crystal material may have a positive dielectric anisotropy. The second component may have a molecular weight not exceeding 205 grams/mole. Embodiments relate to a display device comprising the present material. Another aspect includes a method of increasing the switching speed in a display that employs the present material.

Abstract: A liquid crystal display including driver circuitry which applies a series of voltage pulses at a frequency of approximately 60 Hz. to cumulatively change a reflectance state of a pixel in an array of pixels at a near video updating rate. The display includes a near video rate updating portion, while the remainder of the display has a slower updating frequency or rate. The display is comprised of a bistable cholesteric liquid crystal material sandwiched between an electrode array having a plurality of row and column electrodes. In one operating embodiment, the driver circuitry generates a unipolar row and column waveforms, the row waveforms being applied to the row electrodes and the column waveforms being applied to the column electrodes of the near video rate updating portion. Approximately every 16 milliseconds, a pixel in the near video rate updating portion receives a control voltage pulse corresponding to the difference between the row and column waveforms.

Abstract: A liquid crystal display device includes cell wall structure and a chiral nematic liquid crystal material. The cell wall structure and the liquid crystal cooperate to form focal conic and twisted planar textures that are stable in the absence of a field. A device applies an electric field to the liquid crystal for transforming at least a portion of the material to at least one of the focal conic and twisted planar textures. The liquid crystal material has a pitch length effective to reflect radiation having a wavelength in both the visible and the infrared ranges of the electromagnetic spectrum at intensity that is sufficient for viewing by an observer. One liquid crystal material may be disposed in a single region or two liquid crystal materials may be used, each in separate regions. One aspect of the invention is directed to a photolithography method for patterning a substrate of the display. The display may also have multicolor capabilities by including at least two materials that reflect visible light.