Technology Papers
A brief abstract of the paper is provided under the title. Should you wish more, simply clicking on the title will open the full paper in a new window.
A brief abstract of the paper is provided under the title. Should you wish more, simply clicking on the title will open the full paper in a new window.
Optimization of Stacks of Reflective Cholesteric Films for Full Color Displays
Researchers from Kent Displays recently demonstrated, bright, full color, reflective displays using stacks of red, green and blue reflective cholesteric films. We examined the factors affecting the brightness of these stacked displays. We measured the reflectivity of the individual films and of the two and three layer stacks. We found that the reflectivity depends on the order of these stacks, being maximized when films reflecting at shorter wavelengths are placed on top.
Optical Properties of the Gray-Scae States of Cholesteric Reflective Displays
We studied the bistable cholesteric reflective display in gray scale states. The display exhibits wide viewing angles with no gray scale inversions. By modeling the refection spectra, we characterized the helical axis orientations, the pitch variations and the effective volume fractions of the gray scale states.
Multiple Color High Resolution Reflective Cholelesteric Liquid Crystal Displays
A high-resolution multiple-color and black-on-white surface-stablized reflective cholesteric liquid-crystal display with reflectivities as high as 40% is reported. The double-stacked 1/8-VGA, 100-dpi prototype shows four vivid colors with negligible parallax. The potential for eight colors and ultimately full color is demonstrated in a high-resolution triple-stacked prototype.
Multi-Color, Cholesteric Displays Uisng Plastic Substrates
Bistable, reflective cholesteric displays are well suited for use with plastic substrates. They do not require polarized light, allowing use of birefringent substrates. Bistability produces high-resolution displays using simple matrix addressing. We fabricated multi-color, staked displays using aroll-to-roll processing. We analyzed the optics of these displays and the effects of the birefringent substrates.
Full Color Reflective Cholesteric Liquid Crystal Display
We report a full color 1/4 VGA reflective cholesteric display with 4096 colors. The display can deliver a brightness approaching 40% reflected luminance, far exceeding all other reflective technologies. With its aero voltage bistability, images can be stored for days and months without any power consumtion. This property can significantly extend battery life. The capability of displaying full color complex graphics and images is a must in order to establish a market position in this multimedia age.
Advances in Ch-LCD Devices using Plastic Substrates with Conductiong Polymer
Cholesteric liquid crystal displays (Ch-LCD) are lightweight, low power, sunlight readable displays. In addition they can serve as dual function as pen-input devices with no additional hardware. Because of the unique properties of this technology, ChLCDs can be mad with plastic substrates thus making the displays extremely lightweight, compact and unbreakable. We discuss in this paper recent advances in merging ChLCD technology with conducting polymer electrodes.
Dual Frequency Cholesteric Liquid Crystal Reflective Display
We developed a bistable cholesteric reflective display using a dual frequency cholesteric liquid crystal. When a high frequency voltage is applied to the material, it exhibits a negative dielectric anisotropy and is switched to the planar texture which is Bragg reflecting. When a low frequency voltage is applied to the material, it exhibits a positive dielectric anisotrophy and is switched to the focal conic texture which is weakly scattering. Both the planar and the focal conic textures are stable at zero field and therefore the material can be used to make multiplexed displays with passive matrix. This new display can be directly switched between the planar texture and the focal conic texture, and therefore it is suitable for displaying dynamic images.
Observation of Pattern Evolution during Homeotropic-Focal Conic Transition in Cholesteric Liquid Crystals
We have observed an interesting pattern evoltution of cholesteric liquid crystals during the homeotropic state, if the field is reduced to an appropriate bias level focal conics grow at a constant speed, being an open or compact structure depending on the field strength. We phenomenologically explain the observation.
Electro-optical Properties of Dual Frequency Choleteric Liquid Crystal Reflective Display and Drive Scheme
We developed a bistable cholesteric reflective display using a dual frequency cholesteric liquid crystal. The material exhibits two stable states at zero field: Bragg reflecting planar texture and nonreflecting (weakly scattering) focal conic texture. It can be switched directly from the planar texture to the focal conic texture by a low frequency voltage and back to the planar texture by a high-frequency voltage. We have designed a drive scheme for the display, which uses simultaneous application of both low and high frequency voltages and cumulative effect of the cholesteric liquid crystals.
NVG Compatible Cholesteric Reflective Technology
On the battlefield, timely and accurate information is crucial to success. Kent Displays' Night Vision display has been developed to display messages, graphics, and photographs that are easily viewed in daylight as well as at night. While its high contrast design is ideal for viewing information in direct sunlight, it also provides exceptional readability at night - with zero light emissions.