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1. (WO1998050822) ZERO FIELD MULTISTABLE CHOLESTERIC LIQUID CRYSTAL DISPLAYS
Latest bibliographic data on file with the International Bureau

Pub. No.: WO/1998/050822 International Application No.: PCT/US1997/006747
Publication Date: 12.11.1998 International Filing Date: 18.04.1997
Chapter 2 Demand Filed: 10.11.1998
IPC:
G02F 1/137 (2006.01) ,G02F 3/02 (2006.01)
G PHYSICS
02
OPTICS
F
DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH IS MODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THE DEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY, COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g. SWITCHING, GATING, MODULATING OR DEMODULATING; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF; FREQUENCY-CHANGING; NON-LINEAR OPTICS; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
1
Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
01
for the control of the intensity, phase, polarisation or colour
13
based on liquid crystals, e.g. single liquid crystal display cells
137
characterised by a particular electro- or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction, dynamic scattering
G PHYSICS
02
OPTICS
F
DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH IS MODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THE DEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY, COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g. SWITCHING, GATING, MODULATING OR DEMODULATING; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF; FREQUENCY-CHANGING; NON-LINEAR OPTICS; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
3
Optical logic elements; Optical bistable devices
02
Optical bistable devices
Applicants:
ADVANCED DISPLAY SYSTEMS, INC. [US/US]; Building 1 10901 Airport Boulevard Amarillo, TX 79111, US
Inventors:
WU, Bao-Gang; US
GAO, Jianmi; US
ZHOU, Hongxi; US
MA, Yao-Dong; US
Agent:
CHWANG, T. Ling; Hitt Chwang & Gaines, P.C. 225 University Plaza 275 West Campbell Road Richardson, TX 75080, US
Priority Data:
Title (EN) ZERO FIELD MULTISTABLE CHOLESTERIC LIQUID CRYSTAL DISPLAYS
(FR) AFFICHEURS A CRISTAUX LIQUIDES CHOLESTERIQUES MULTISTABLES A CHAMP ZERO
Abstract:
(EN) A light modulating apparatus containing cholesteric liquid crystals capable of indefinite zero field retention of optical images, including full color and complete gray scale capability, is described. This invention is predicated on establishment of zero field multistable liquid crystal domains representing a continuous distribution of states ranging from the highly reflective planar to the light-scattering focal-conic structures. The zero field multistable domain structure stability is achieved by controlling solid surface-liquid crystal boundary interactions to provide essential equalization of the total system energy of each of the domain structures. This equalization has been achieved without the use of a polymer gel addition to create rigid polydomains in the liquid crystal mix. The establishment of a particular domain structure is controlled using either a single relative long voltage pulse or a number of shorter duration successive voltage pulses. The zero field multistability achieved is remarkably stable against both mechanical shocks and thermal variations. These displays eliminate the need for backlighting and image refreshing input, and for polarizers, analyzers, retarder and color filters. They can also be fabricated as flexible all-plastic units.
(FR) L'invention concerne un appareil modulateur optique contenant des cristaux liquides cholestériques capable de rémanence optique indéfinie à champ zéro, présentant des propriétés de couleur pure et une gamme de gris complète. Cette invention concerne l'établissement des domaines de cristaux liquides multistables à champ zéro représentant une distribution continue d'états allant des structures planes hautement réfléchissantes aux structures focales-coniques diffusant la lumière. On obtient une stabilité de la structure à domaine multistable à champ zéro en régulant les intéractions entre les limites de la surface solide et des cristaux liquides afin d'assurer une correction essentielle de l'énergie totale dus système de chacune des structures. On a effectué cette correction sans avoir à recourir à l'addition d'un gel polymère destiné à créer des polydomaines rigides dans le mélange des cristaux liquides. On régule l'établissement d'une structure de domaine particulière au moyen d'une seule décharge électrique relativement longue ou d'un certain nombre de décharges électriques de courte durée en série. La multistabilité à champ zéro obtenue est remarquablement stable même sous l'effet des chocs mécaniques et des variations thermiques. Grâce à ces afficheurs, l'éclairage en contre-jour et la régénération d'images, ainsi que les filtres polarisants, les analyseurs, les filtres retardateurs et les filtres colorés sont inutiles. Ces afficheurs peuvent être fabriqués comme unités flexibles en plastique.
Designated States: AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GE, GH, HU, IL, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, TJ, TM, TR, TT, UA, UG, UZ, VN, YU
African Regional Intellectual Property Organization (ARIPO) (GH, KE, LS, MW, SD, SZ, UG)
Eurasian Patent Organization (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM)
European Patent Office (AT, BE, CH, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE)
African Intellectual Property Organization (BF, BJ, CF, CG, CI, CM, GA, GN, ML, MR, NE, SN, TD, TG)
Publication Language: English (EN)
Filing Language: English (EN)
Also published as:
AU1997028077