Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—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
  • G02F1/01—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 for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—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 for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
  • G02F1/13363—Birefringent elements, e.g. for optical compensation
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—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
  • G02F1/01—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 for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—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 for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—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
  • G02F1/01—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 for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—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 for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
  • G02F1/133528—Polarisers
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—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
  • G02F1/01—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 for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—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 for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/133345—Insulating layers
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—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
  • G02F1/01—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 for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—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 for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
  • G02F1/13356—Structural association of cells with optical devices, e.g. polarisers or reflectors characterised by the placement of the optical elements
  • G02F1/133565—Structural association of cells with optical devices, e.g. polarisers or reflectors characterised by the placement of the optical elements inside the LC elements, i.e. between the cell substrates
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F2413/00—Indexing scheme related to G02F1/13363, i.e. to birefringent elements, e.g. for optical compensation, characterised by the number, position, orientation or value of the compensation plates
  • G02F2413/02—Number of plates being 2

Definitions

• the herein invention pertains to devices for displaying information, in particular to elements of liquid crystal (LC) displays.
• LC liquid crystal
• liquid crystal displays are implemented in the form of a flat cuvette, formed having two parallel plates, on the inner surfaces of which there has been provided a system of electrodes made of optically transparent conducting material (for example, solid solution SnO 2 and I 2 O - ITO).
• the surfaces of plates with electrodes are usually coated with a layer of polyimide or other polymer and then subjected to a special processing, which provides the particular uniform orientation of molecules of the liquid crystal (LC) near the surfaces of the plates as well as in the bulk of liquid crystal layer in the display.
• LC liquid crystal
• LC represents the active medium, changing its optical properties under the influence of electric field.
• the change in optical properties is registered in crossed polarizers, which are usually adhered on the outer sides of the cuvette [L.K. Vistin. JVHO, 1983, vol. XXVII, ed.2, pp.141-148].
• display panels are fabricated out of plates having glass substrate and a conducting layer.
• the glass plates should be very flat and be free from bubbles and other optical defects.
• the conducting layers are transparent.
• the front plate of the display is made with transparent conducting layer, and the rear one - with reflecting conducting layer.
• Transparent conducting layers have surface resistance from 10 to 10 Ohm, and transmission coefficient of 0.7 - 0.9 in the visible region of the spectrum. Conducting layers are formed via well-known deposition methods.
• Electrodes come out to the edge of the glass, where they terminate with the contact pad for attaching external leads.
• Separate panels are divided by etched grooves, along which the displays are later glued together. To create the necessary gap between the panels, they are separated by spacers along their perimeter.
• Assembled display panel (or a matrix of panels) is filled with LC material in vacuum, while the plates are heated. This provides lower viscosity of LC and better filling of the gap between the panels of the display. Displays in the matrix are then separated from each other (scribed and broken) and each cuvette is then sealed. Polarizers protected by the protective layer and/or covered by a glass plate are adhered on the outside of the cuvette.
• the conducting layer is usually separated from the glass by a protective layer.
• this protective layer is a film of silicon oxide or oxides of heavy metals, although some polymers may also be used.
• the Protective layer should be transparent in the working region of the spectrum, and its thickness and density should provide dependable isolation of glass from LC.
• the other physical method is cathode sputtering.
• the process is based on knocking out atoms of a cathode material by bombarding it with ions of rarefied gas with high energy. Atoms knocked out of the surface of the cathode settle down on the substrate.
• the working chamber is filled with active gas (for example, oxygen), which allows obtaining films with necessary chemical composition.
• One of the chemical methods is the method of forming films from solutions of hydrolyzing compounds. Then the oxide film is formed by application of silicon-ethyl solution onto the blank rotating in a centrifuge.
• Patent US 5,358,739, 1994 describes the method of silicon oxide coatings via application of sylazane polymer onto the substrate and heating it in oxidizing medium. There are other methods as well.
• polarizer obtainable from liquid crystal solutions of organic dyes.
• a polarizer according to this technology is fabricated via depositing thin film of LC solution of the dye onto glass of polymer substrate with one of the known methods.
• the peculiarity of this technology is in the fact that orientation of molecules of the dye happens during deposition of the film, so that a thin thermally stable polarizing coating appears on the substrate directly after its drying.
• Application of these polarizers allows creating new configurations of liquid crystal displays, where polarizers may be formed directly on the walls of LC cuvette, on its inner as well as external sides. Internal positioning of polarizers appears more favorable, since it allows enhancing durability and dependability of the display, as well as simplifying its design and decreasing the number of fabrication operations.
• dichroic polarizer comprising anisotropic film, at least a part of which has crystalline structure [PCT RU99/00400].
• Such dichroic polarizers possess higher degree of anisotropy and thermal stability.
• the dichroic polarizer is usually formed above the system of electrodes [RU2139559].
• electrodes are coated with special planarizing layer, which also promotes good adhesion of the dichroic polarizer. This leads to an increase in the number of layers in the display (its thickness) and the number of manufacturing operations.
• dichroic polarizer may be deposited only after creation of the electrode system, which lowers flexibility of manufacturing process in order to change assortment of products.
• the herein invention is aimed at creating a multilayer plate, which can be used in display manufacturing, as well as designing of displays with internal polarizers.
• the technical result of the disclosed invention is the increase of durability and decrease of thickness of displays, as well as lowering the cost of their manufacturing, increase of useful yield and decrease of the number of manufacturing operations.
• multilayer plate comprises optically transparent substrate, protective layer, conductive layer and at least one layer of anisotropic membranous crystal.
• the membranous crystal is created by a material, which contains aromatic rings and has Bragg peak at 3.4 ⁇ 0.2 A along one of the optical axes.
• At least one layer of the membranous crystal is situated between the substrate and the conducting layer and separated from the latter by the protective layer.
• Material of the membranous crystal may contain heterocycles.
• the substrate of the multilayer plate may be made of glass, while the protective layer may be made out of silicon oxide and/or oxide(s) of heavy metal(s) or polymer(s).
• the conducting layer is usually made out of ITO.
• the layer of ITO may be deposited onto a metal grid (for example, via mask sputtering) in order to increase conductivity of the layer. Then total surface area of the metal grid should be less than 10% of the total area of the multilayer plate.
• membranous crystal represents an E-type polarizer.
• membranous crystal may simultaneously function as the polarizer and as phase-shifting layer.
• the protective layer may be made conductive by, for example, doping its surface.
• the display panel comprises optically transparent substrate, protective layer, a system of electrodes and at least one layer of membranous crystal.
• the membranous crystal is formed by the material comprising aromatic rings and has Bragg peak at 3.4 ⁇ 0.2 A along one of the optical axes.
• at least one layer of membranous crystal is situated between the substrate and the system of electrodes and is separated from the latter by the protective layer.
• Material of the membranous crystal may contain heterocycles.
• the substrate of the display panel may be implemented out of glass.
• Protective layer may be implemented out of silicon oxide and/or oxide(s) of heavy metal(s) or polymer(s).
• the system of electrodes is usually made of ITO.
• a metal grid may be deposited onto the layer of ITO in the panel of the display. Then total surface area of the grid should be less than 10% of the total area of electrodes.
• Membranous crystal in the display usually represents an E-type polarizer.
• membranous crystal in the display may combine functions of polarizer and of phase-shifting layers.
• Display panel may additionally comprise adhesion layer(s).
• the multilayer plate according to the disclosed invention comprises the following main layers: optically transparent substrate (usually soda-lime glass), optically anisotropic layer - membranous crystal formed by material containing aromatic cycles and having Bragg peak at 3.4 ⁇ 0.2 A along one of the optical axes, protective layer, for example silicon oxide, and conducting layer, usually ITO.
• optically transparent substrate usually soda-lime glass
• optically anisotropic layer - membranous crystal formed by material containing aromatic cycles and having Bragg peak at 3.4 ⁇ 0.2 A along one of the optical axes
• protective layer for example silicon oxide
• conducting layer usually ITO.
• Optically anisotropic layer performs as the polarizer in the display, or simultaneously as the polarizer and as phase-shifting layer. It is necessary that this layer is at least partially crystalline; this will provide high durability of its structure and the required optical parameters.
• the initial choice of material for this layer is determined by the presence of developed system of ⁇ -conjugate bonds in the aromatic cycles and the presence of groups like amine, phenol, ketone and other, lying in the planes of molecules and being a part of the aromatic bond system of these molecules. Molecules themselves, or their fragments have flat construction.
• indanthrone Vat Blue 4
• dibenzoimidazolel, 4,5,8- naphthalentetracarboxylic acid Vat Red 14
• dibenzoimidazole 3,4,9,10- perylenetetracarboxylic acid or quinacridone (Pigment Violet 19) or other, derivatives of which or their mixtures form stable lyotropic liquid crystal phase.
• colloid system lyotropic liquid crystal
• LC is the pre-ordered state of the system, from which, in the process of alignment of the supramolecular complexe
• the method of obtaining membranous crystals from colloid system with supramolecular complexes comprises:
• the colloid system should also be thixotropic, for which purpose the colloid system should be at certain temperature and have certain concentration of the dispersion phase;
• the degree of the said aligning influence should be sufficient for kinetic units of the colloid system to obtain the necessary orientation and form the structure, which will be the foundation of the future crystalline lattice of the forming layer;
• the concluding operation is usually the conversion of membranous crystal into water-insoluble form, via processing its surface with solution containing ion of 2- and 3 -valence metals.
• the planes of molecules in the obtained layer are parallel to each other and the molecules form three-dimensional crystal, in at least a part of the layer.
• this fabrication method it is possible to obtain mono-crystalline layers.
• Optical axis in such membranous crystal will be perpendicular to the planes of molecules.
• Such membranous crystal will possess high degree of anisotropy and high refraction index for at least one direction.
• Control over the thickness of the layer is performed through the content of solid matter in the depositing solution and thickness of the wet layer on the substrate.
• Manufacturing parameter in fabricating such films is the concentration of the solution, which is conveniently controlled during fabrication.
• the degree of crystallinity of the layer may be controlled using rontgenogram or optical methods.
• the distinctive feature of the membranous crystal is the high thermal stability, which is especially important in the contemporary technology of display fabrication.
• the layer of silicon oxide is necessary to protect the anisotropic layer from destructive external impacts during fabrication process, in particular during etching of ITO, and insulating it from the contact with electrodes and LC during operation of the display.
• the layer of silicon oxide is formed using the known methods: evaporation in vacuum while heating, cathode sputtering, the so-called "wet method” - from solutions and others.
• Protective layer, aside from the silicon oxide, may also contain oxides of heavy metals.
• composition of CERAMATE used for creating protective layer from solution, contains up to 6 % wt. of solid phase (TiO 2 , ZrO 2 , SiO 2 , Sb 2 O ).
• the layer obtainable from solution is usually baked at high temperature. Performing this operation in the process of fabricating multilayer plates is possible due to high thermal stability of the anisotropic layer. It can withstand heating up to 180°C or brief heating up to 250°C and higher without significant modification of optical characteristics.
• thermal stability of all layers in the multilayer plate is necessary, since a number of manufacturing operations (for example, creating planarizing and aligning layer of polyimide on top of the system of electrodes) include heating to a high temperature.
• Conducting layer is formed via one of the known methods.
• the multilayer plate may contain additional external layers, which protect it during transportation, and which can be removed during fabrication of displays.
• Such multilayer plate represents the blank for fabricating display panels and already contains main functional layers of the display. This allows simplifying technology of fabricating liquid crystal displays by cutting down the number of manufacturing operations. Dimensions of the multilayer plate are determined by the requirements set forth by the manufacturers of displays. Usually, each plate accommodates several display panels. Area of each display panel on the plate is equipped with corresponding electrode system and grooves, along which the displays are later glued together. Removal of material of the conducting layer on the corresponding areas of the plate may be performed via photolithography, laser ablation, etc.
• Density and thickness of the protective layer should be sufficient, in order to prevent destruction of the anisotropic membranous crystal during photolithography and other analogous methods of etching of the conducting layer.
• the silicon oxide protective layer may be fused together with the glass.
• the system of electrodes is usually coated with polyimide layer, which functions as the planarizing and LC aligning layer.
• polyimide layer which functions as the planarizing and LC aligning layer.
• Other materials could be used in the capacity of the planarizing layer, in particular, silicon oxide.
• material of this layer will additionally function as the insulator, preventing discharge between electrodes.
• figure 1 presents diagram of the multilayer plate according to the disclosed invention
• figure 2 presents diagram of the liquid crystal display with internal polarizers.
• Multilayer plate in one of examples of embodiment comprises optically transparent substrate 1 made out of soda- lime glass and polarizer 2, which represents membranous crystal made from 9.5% aqueous solution of sulfonated indanthrone.
• the thickness of the polarizer is about lOOnm.
• Silicon oxide protective layer 3 is deposited over the polarizer, and then conducting layer 4, usually ITO is deposited on top of that. During transportation the plate is usually protected by polymer films 5.
• Such multilayer plate represents the blank for manufacturing display panels and already bears the main functional layers of the display.
• One of the possible designs of the display with internal polarizes is presented in the Fig. 2.
• the display represents a flat cuvette, created by two parallel glass plates 6, on the inner surface of which the following layer have been sequentially formed: layer of polarizer 2, protective layer 3 of silicon oxide, system of electrodes 7 made from optically transparent conducting material (ITO) and layer 8 of polyamide, which is the aligning layer.
• layer of polarizer 2 protective layer 3 of silicon oxide
• system of electrodes 7 made from optically transparent conducting material (ITO)
• layer 8 of polyamide which is the aligning layer.
• the design of the display with internal polarizers allows decreasing the thickness of the device and enhancing its reliability in operation. Besides that, optical properties of membranous crystals utilized in such displays as anisotropic layers, allow creating devices with contrast and wide observation angle.

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• Nonlinear Science (AREA)
• Mathematical Physics (AREA)
• Chemical & Material Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Liquid Crystal (AREA)
• Polarising Elements (AREA)

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• 2001
  • 2001-10-02 RU RU2001126491/28A patent/RU2226293C2/ru not_active IP Right Cessation
• 2002
  • 2002-10-01 KR KR10-2004-7004819A patent/KR20040047882A/ko not_active Application Discontinuation
  • 2002-10-01 JP JP2003533038A patent/JP2005530185A/ja active Pending
  • 2002-10-01 CN CNB028226941A patent/CN1325970C/zh not_active Expired - Fee Related
  • 2002-10-01 EP EP02800453A patent/EP1449023A1/de not_active Withdrawn
  • 2002-10-01 WO PCT/US2002/031512 patent/WO2003029883A1/en active Application Filing

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