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1. WO2006122899 - A SINGLE-POLARIZER REFLECTIVE BISTABLE TWISTED NEMATIC (BTN) LIQUID CRYSTAL DISPLAY DEVICE

Publication Number WO/2006/122899
Publication Date 23.11.2006
International Application No. PCT/EP2006/062203
International Filing Date 10.05.2006
IPC
G02F 1/13363 2006.01
GPHYSICS
02OPTICS
FDEVICES 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
1Devices 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
01for the control of the intensity, phase, polarisation or colour
13based on liquid crystals, e.g. single liquid crystal display cells
133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
1333Constructional arrangements
1335Structural association of cells with optical devices, e.g. polarisers or reflectors
13363Birefringent elements, e.g. for optical compensation
G02F 1/139 2006.01
GPHYSICS
02OPTICS
FDEVICES 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
1Devices 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
01for the control of the intensity, phase, polarisation or colour
13based on liquid crystals, e.g. single liquid crystal display cells
137characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
139based on orientation effects in which the liquid crystal remains transparent
G02F 1/1335 2006.01
GPHYSICS
02OPTICS
FDEVICES 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
1Devices 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
01for the control of the intensity, phase, polarisation or colour
13based on liquid crystals, e.g. single liquid crystal display cells
133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
1333Constructional arrangements
1335Structural association of cells with optical devices, e.g. polarisers or reflectors
CPC
G02F 1/133531
GPHYSICS
02OPTICS
FDEVICES 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
1Devices 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
01for the control of the intensity, phase, polarisation or colour 
13based on liquid crystals, e.g. single liquid crystal display cells
133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
1333Constructional arrangements; ; Manufacturing methods
1335Structural association of cells with optical devices, e.g. polarisers or reflectors
133528Polarisers
133531characterised by the arrangement of polariser or analyser axes
G02F 1/133567
GPHYSICS
02OPTICS
FDEVICES 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
1Devices 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
01for the control of the intensity, phase, polarisation or colour 
13based on liquid crystals, e.g. single liquid crystal display cells
133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
1333Constructional arrangements; ; Manufacturing methods
1335Structural association of cells with optical devices, e.g. polarisers or reflectors
13356characterised by the placement of the optical elements
133567on the back side
G02F 1/133634
GPHYSICS
02OPTICS
FDEVICES 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
1Devices 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
01for the control of the intensity, phase, polarisation or colour 
13based on liquid crystals, e.g. single liquid crystal display cells
133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
1333Constructional arrangements; ; Manufacturing methods
1335Structural association of cells with optical devices, e.g. polarisers or reflectors
13363Birefringent elements, e.g. for optical compensation
133634the refractive index Nz perpendicular to the element surface being different from in-plane refractive indices Nx and Ny, e.g. biaxial or with normal optical axis
G02F 1/1391
GPHYSICS
02OPTICS
FDEVICES 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
1Devices 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
01for the control of the intensity, phase, polarisation or colour 
13based on liquid crystals, e.g. single liquid crystal display cells
137characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
139based on orientation effects in which the liquid crystal remains transparent
1391Bistable or multi-stable liquid crystal cells
Applicants
  • NEMOPTIC [FR]/[FR] (AllExceptUS)
  • JOUBERT, Cécile [FR]/[FR] (UsOnly)
  • SCHEFFER, Terry [US]/[US] (UsOnly)
Inventors
  • JOUBERT, Cécile
  • SCHEFFER, Terry
Agents
  • CABINET REGIMBEAU
Priority Data
05291087.420.05.2005EP
Publication Language English (EN)
Filing Language English (EN)
Designated States
Title
(EN) A SINGLE-POLARIZER REFLECTIVE BISTABLE TWISTED NEMATIC (BTN) LIQUID CRYSTAL DISPLAY DEVICE
(FR) DISPOSITIF D'AFFICHAGE A CRISTAUX LIQUIDES BISTABLES NEMATIQUES TORSADES (BTN) RETROREFLECHISSANT A POLARISEUR UNIQUE
Abstract
(EN)
The application relates to a single-polarizer reflective bistable twisted nematic (BTN) liquid crystal display device comprising a liquid crystal layer (150) of thickness d, birefringence &Dgr;n and retardation &Dgr;nd, said liquid crystal layer being situated between two substrates (120, 180) and between a polarizer (100) and a reflector (200), said liquid crystal layer (150) in the absence of an applied electric field having two stable uniformly twisted textures, the twists of the two stable textures differing by an angle being equal mainly to 180°, and at least one compensation layer (110) positioned between said polarizer (100) and said reflector (200), said compensation layer (110) being composed of at least one birefringent film, said birefringent film having an optical anisotropy defined by three characteristic refractive indices nx, ny, nz, along three corresponding axis x, y, z of index ellipsoid, x and y being situated inside the substrates plane, nx and ny being called in plane indices, with nx ≥ ny, x being called slow axis, and z being perpendicular to the substrates plane (120, 180) with biaxiality parameter Nz equal to (nx- nz)/(nx-ny), characterized in that Nz lies between - ∞ and ½ so that under oblique viewing the retardation of the stable texture corresponding to the dark state is compensated to improve the contrast ratio and simultaneously the retardation of the stable texture corresponding to the bright state is modified to decrease the color shift.
(FR)
L'invention concerne un dispositif d'affichage à cristaux liquides bistables nématiques torsadé (BTN) rétroréfléchissant à polariseur unique comprenant une couche de cristaux liquides (150) d'épaisseur d, de biréfringence &Dgr;n et de retardement &Dgr;nd. La couche de cristaux liquides (150) est située entre deux substrats (120, 180) et entre un polariseur (100) et un réflecteur (200). En l'absence de champ électrique appliqué, la couche de cristaux liquides (150) présente deux textures torsadées uniformément stables, les torsades des deux textures stables différant d'un angle sensiblement égal à 180°, et au moins une couche de compensation (110) disposée entre le polariseur (100) et le réflecteur (200), laquelle couche de compensation (110) est composée d'au moins un film biréfringent. Ce film biréfringent présente une anisotropie optique définie par trois indices caractéristiques de réfraction nx, ny, nz, le long de trois axes correspondants x, y, z d'un indice ellipsoïde, x et y étant situés dans le plan des substrats, nx et ny représentant des indices du plan, nx ≥ ny, x représentant un axe lent et z étant perpendiculaire aux plans des substrats (120, 180) avec un paramètre de biaxialité Nz égal à (nx- nz)/(nx-ny), caractérisé en ce que Nz est situé entre - ∞ et ½ de sorte que, vu sous un angle oblique, le retardement de la texture stable correspondant à l'état sombre est compensé afin d'améliorer le rapport de contraste et, simultanément, le retardement de la texture stable correspondant à l'état lumineux est modifié pour diminuer la distorsion de la couleur.
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