Kent Displays, Inc.

Manning Ventures, Inc.

Kent State University

Xiao-Yang Huang

Asad Aziz Khan

Nick Martin Miller, Iv

Minhua Lu

Haiji J Yuan

Donald J Davis

J William Doane

Deng-ke Yang

Duane Marhefka

Todd C Ernst

Ellison C Urban, Ii

Gene A Miceli

Philip J Bos

Deng-Ke Yang

Yang-Ming Zhu

Kellie D Hoke

Nick M Miller

Chris Blackson

A device and method providing a pixel architecture that, in at least one embodiment, contains both an on/off memory element and a switching element to utilize low-power liquid crystal displays for video or near-video applications. Such an embodiment can be implemented, for example, using a pair of TFTs for implementing the memory element and switching element on a common substrate. Other embodiments can utilize actual memory devices for the memory elements. This device and method are particularly useful for driving cholestric display elements for video or near video rate applications.

Video rate ChLCD driving with active matrix backplanes

A stacked color liquid crystal display uses shared electrode addressing including a plurality of liquid crystal layers each sandwiched between electrically conductive layers. Adjacent liquid crystal layers share one or two electrode layers located between the adjacent liquid crystal layers. A driving scheme is provided that allows the display to be driven by updating the liquid crystal layers sequentially, concurrently, or some combination of the two. Further, a method of manufacturing the display using a deposition process is also disclosed.

Stacked display with shared electrode addressing

A device and method for supplying a display, such as a liquid crystal display, for example a bistable ChLCD, with drive voltages for extremely low power operation. The method and the device implementing the method provides an energy storage device and a voltage converter being utilized to store energy in the storage device, such that a display can be driven during an inactive, powered-down phase of the converter by using the stored energy to drive the display.

Power management method and device for low-power displays

A graphics controller for a color display system having a bistable liquid crystal display (LCD) for displaying a plurality of pixels arranged in a matrix includes a memory device for storing color data and status bits corresponding to each of the pixels, and a generating device for generating voltage data corresponding to the pixels based on the color data and the status bits for each of the pixels. In an exemplary case, the bistable LCD is a Cholesteric LCD. Preferably, the generating device has a first mode of operation in which the data corresponding to the pixels is generated for each corresponding pixel and a second mode of operation in which no data is generated; the generating device switches from the first operating mode to the second operating mode when all of the status bits for all of the pixels are zeros.

Graphic controller for active matrix addressed bistable reflective Cholesteric displays

A modular and configurable display driver for driving a bistable liquid crystal display. The driver has configurable outputs set by a plurality of configuration bits for driving rows or columns of various displays configurations. Thus, the driver can be economically mass produced for use in many products.

Multi-configuration display driver

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 or more liquid crystal materials may be used, each in separate regions even without the infrared reflecting layer. 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 separate layers of at least two or three liquid crystal materials that reflect visible light. A full color stacked display may be produced with grey scale capabilities.

Stacked color liquid crystal display device

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.

Drive schemes for gray scale bistable cholesteric reflective displays utilizing variable frequency pulses

An operating method for a color display system including an active matrix bistable liquid crystal display (LCD) having a plurality of pixels arranged in a matrix based on color data and status bits corresponding to each of the pixels stored in a memory includes steps for generating voltage data corresponding to the pixels based on the color data and the status bits stored for each of the pixels, converting the voltage data to drive signals suitable for driving the active matrix bistable LCD, and applying the drive signals to the active matrix bistable LCD. In an exemplary embodiment, the active matrix bistable LCD is a Cholesteric LCD. Advantageously, the generating, converting, and applying steps are repeated for a corresponding pixel N times, where N is an integer established by the status bits.

Operating method for active matrix addressed bistable reflective cholesteric displays

A low power color display system includes a memory which, stores color data and status bits corresponding to a plurality of pixels, status logic, which generates the status bits responsive to receipt of color data for a respective one of the pixels, a data generator, which generates voltage data corresponding to the pixels based on the color data and the status bits for each of the pixels, driver circuitry, which generates voltage signals responsive to receipt of the voltage data for each of the pixels, and a bistable liquid crystal display (LCD) having multiple cells arranged in a matrix, each cell corresponding to a pixel, the LCD being responsive to the voltage signals. Preferably, the system also includes a power supply which provides power to the driver circuitry, and a power manager, the latter turning the power supply ON when the data generator is in the first operating mode and turning the power supply OFF when the data generator is in the second operating mode. The data generator generates the voltage data for a corresponding pixel N times to thereby permit application of the voltage signal corresponding to the pixel data to the LCD N time, where N is an integer established by the status bits.

Active matrix addressed bistable reflective cholesteric displays

Graphic controller for active matrix addressed bistable reflective cholesteric displays

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 treat 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. Such a cell may employ an alignment layer material with a high pretilt angle. A stacked display may be produced including at least one cell with at least one homogeneous alignment surface. In particular, a stacked cell display may include a lower cell with two homogeneous alignment surfaces and an upper cell in which the top side has an inhomogeneous alignment surface and the bottom side has a homogeneous alignment surface. The present invention achieves any one or combinations of the above features through the use of the homogeneous alignment surface produced with a predetermined alignment layer material and predetermined alignment conditions. The invention also includes a method of making the inventive display and the stacked inventive display.

Brightness enhancement for bistable cholesteric displays

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. Such a cell may employ an alignment layer material with a high pretilt angle. A stacked display may be produced including at least one cell with at least one homogeneous alignment surface. In particular, a stacked cell display may include a lower cell with two homogeneous alignment surfaces and an upper cell in which the top side has an inhomogeneous alignment surface and the bottom side has a homogeneous alignment surface. The present invention achieves any one or combinations of the above features through the use of the homogeneous alignment surface produced with a predetermined alignment layer material and predetermined alignment conditions. The invention also includes a method of making the inventive display and the stacked inventive display.

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.

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Stow, OH, United States of America

Xiao-Yang Huang