WO1999026107A1 - A liquid crystal display device and method of fabrication - Google Patents
A liquid crystal display device and method of fabrication Download PDFInfo
- Publication number
- WO1999026107A1 WO1999026107A1 PCT/GB1998/003446 GB9803446W WO9926107A1 WO 1999026107 A1 WO1999026107 A1 WO 1999026107A1 GB 9803446 W GB9803446 W GB 9803446W WO 9926107 A1 WO9926107 A1 WO 9926107A1
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- WIPO (PCT)
- Prior art keywords
- liquid crystal
- layer
- crystal material
- electrodes
- array
- Prior art date
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Classifications
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- 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
- G02F1/137—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
- G02F1/13718—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering based on a change of the texture state of a cholesteric liquid crystal
-
- 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
- G02F1/133509—Filters, e.g. light shielding masks
- G02F1/133514—Colour filters
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- 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
- G02F1/137—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
- G02F1/13775—Polymer-stabilized liquid crystal 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
- G02F1/137—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
- G02F1/13781—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 characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering using smectic liquid crystals
-
- 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
- G02F2203/00—Function characteristic
- G02F2203/02—Function characteristic reflective
Definitions
- This invention relates to a liquid crystal display (LCD) device and its method of fabrication, and more particularly to a reflective type liquid crystal display device which has a low energy consumption.
- LCD liquid crystal display
- Liquid crystal materials change their optical properties when subjected to an electric field. This phenomenon has been used, with great success, in a number of display devices of the type found for example in portable (lap top) computers, hand-held (notebook and palmtop) organisers, clocks, watches and increasingly flat screen television displays and desktop monitors.
- Liquid crystal displays have proven to be very successful and are now widespread. They comprise a liquid crystal material interposed between two transparent sheets of glass. Transparent conductors, which are typically Indium Tin Oxide (ITO), are deposited on the glass so as to provide a means of addressing individual portions of the display known as pixels. These may be arranged in an array of n rows and m columns.
- ITO Indium Tin Oxide
- the aforementioned type of liquid crystal displays fall into two main categories: the first is where light is reflected off the surface of a liquid crystal display device; the second is where the liquid crystal display device is placed between a viewer and an illumination source. The former operates in a reflective mode; the latter operates in a transmissive mode.
- Liquid crystal display (LCD) devices which operate in the transmissive mode typically use more energy than reflective mode devices because of the power consumed by the illumination source. This energy requirement has limited the number of applications in which transmissive mode liquid crystal displays have been used.
- a further example of a device operating in reflective mode is described in United States Patent US-A-5493430 (Kent Display Systems).
- This device comprises a layer of liquid crystal material having two stable states disposed between first and second substrates.
- a colour imparting layer having one or more colours is disposed adjacent a surface of one of the substrates.
- the focal conic state of a liquid crystal material occurs when liquid crystal helices are randomly distributed.
- the focal conic state of the liquid crystal material is arranged to be weakly scattering (optically transparent), so that the colour(s) of the colour imparting layer are visible.
- the planar texture of a liquid crystal material is defined by the liquid crystal helices being aligned parallel to (in this device) the first and second substrates.
- the planar texture of the liquid crystal material in the device described in US-A-5493430 is arranged to reflect a particular colour selected by the pitch of the material.
- the pitch of the liquid crystal material is selected to reflect a colour which is complementary to the colour of light reflected from a colour imparting layer.
- a blue background may be combined with a liquid crystal material that reflects yellow portions of the spectrum. The result is a white colour reflected on a blue background.
- a disadvantage of this display device is that it does not provide a full colour display.
- liquid crystal effect known as memory is the characteristic that when switched to a particular state, the liquid crystal materials remain in that state even when the electric field is removed.
- liquid crystal materials are known to provide displays with memory. These displays are: polymer stabilised cholesteric texture (PSCT) displays, surface stabilised cholesteric texture displays, ferroelectric liquid crystal displays, and smectic-A displays.
- PSCT polymer stabilised cholesteric texture
- surface stabilised cholesteric texture displays ferroelectric liquid crystal displays
- smectic-A displays smectic-A displays.
- PSCT technology is described in US Patent US-A-5 ,437,811 (Kent State University) and is able to provide multistable states, (i.e. grey levels) with memory, but is used to provide a reflective monochrome display.
- monochrome means a single colour, e.g. red, green, yellow or blue display.
- a stack of two or more PSCT displays is formed, each display being of a different primary colour so that a spectrum of colours is achieved by varying the amount of grey scale voltage applied to each panel.
- a disadvantage of this approach is the cost of the additional displays, the occurrence of parallax between the adjacent displays in the stack and the losses resulting from the ambient light having to pass through three displays and not just one.
- FeiToelectric LCDs are bistable devices. That is, they have only two stable states at zero volts and are therefore not able to provide multistable states (i.e. grey levels) with memory.
- Another disadvantage of ferroelectric LCDs in this context, is that their electro- optic effect relies on the use of polarisers which tend to absorb more than 50% of the light, therefore producing a rather dark display.
- An aim of the present invention is to overcome the aforementioned deficiencies by providing an energy efficient, colour liquid crystal display (LCD) device having grey scale capability and memory.
- LCD liquid crystal display
- a liquid crystal display device comprising: a liquid crystal material disposed between first and second substrates and electrodes for applying an electric field to portions of the liquid crystal material, the liquid crystal material being of the type which can be switched to appear optically transparent in a visible portion of the electro-magnetic spectrum, and which exhibits at least three stable states in dependence upon an applied electric field, and the liquid crystal material being of a type which maintains its switched state when the electric field is removed; and a colour filter disposed between the first and second substrates, said colour filter comprising at least two different colours.
- the invention provides a single full colour liquid crystal display that has memory (and therefore a low power consumption) and one or more grey levels.
- the first and second substrates are preferably glass or other optically transparent material such as PET.
- the colour filter comprises three different colours.
- a reflector is disposed between the colour filter and the second substrate so as to reflect more light back to a viewer.
- the colour filter is positioned substantially adjacent the first substrate. This reduces parallax.
- the colour filter may, however, be disposed between arrays of electrodes formed on the substrates. In this case, the colour filter is preferably positioned substantially adjacent the array of electrodes associated with the first substrate.
- the reflective colour display exhibits memory and provides a plurality of grey levels. At least sixteen grey levels have been found to be suitable.
- the liquid crystal display device advantageously consumes energy at the rate of between 0 W and 0.5 Watts.
- the power consumption of the device depends on how many pixels require switching, and how often the image is to be refreshed. As the display device has memory, if the image remains unchanged, no energy is consumed by the display device.
- the type of liquid crystal incorporated in the liquid crystal display device is preferably a Stabilised Cholesteric Texture (SCT) liquid crystal, such as a Polymer Stabilised Cholesteric Texture (PSCT) or a Surface Stabilised Cholesteric Texture liquid crystal.
- SCT Stabilised Cholesteric Texture
- PSCT Polymer Stabilised Cholesteric Texture
- SCT liquid crystal is arranged so that its planar texture reflects light in the infra-red region of the spectrum, thereby appearing optically clear. When combined with a reflective electrode, this will lead to light being specularly reflected beyond the eye of a viewer, therefore one or more pixels will appear black to the viewer.
- SCT liquid crystal material by arranging the pitch of the SCT liquid crystal to be greater than, or substantially equal to, 0.5 ⁇ m, and most preferably greater than or equal to 0.75 ⁇ m.
- the composition of the SCT liquid crystal may be arranged so that its planar texture reflects light in another non- visible portion of the electromagnetic spectrum, for example in the ultra-violet region of the spectrum.
- the liquid crystal material is arranged so that its focal conic state is strongly scattering, so that in use, the colours of the colour filter are visible to the viewer.
- the thickness of the layer of liquid crystal material is preferably approximately 6 micrometres.
- composition of the liquid crystal material and the dimensions of the display cell may be changed so that a range of states is exhibited. These states range from the planar to the focal conic, with intermediate states giving grey-scale capability to the display device.
- liquid crystal material is not used for imparting colour to the SCT display, but for giving the display device grey-scale capability, is felt to be particularly inventive as this is the first reported use of this technique.
- colour filters are not required for display devices utilising cholesteric texture liquid crystal materials.
- the pitch of the cholesteric texture liquid material is selected so that it reflects light in the visible range of the spectrum.
- liquid crystals suitable for the aforementioned are disclosed in United States Patent US-A-5,437,811 (Kent State University). Moreover the liquid crystal materials described exhibit multiple levels of states so that grey scales may be produced. Hence additional energy is saved using such stabilised liquid crystals.
- the liquid crystal used may be of a smectic-A type liquid crystal material.
- Drive means are provided for driving the display device and may include electronic microprocessors, hereinafter termed processing means.
- Processing means may include devices which switch off an address energising waveform to a pixel whose state remains unchanged during first and subsequent time frames. Such processing means are therefore specifically adapted for use with liquid crystal material which exhibit memory and therefore further reduce the energy demand of the display.
- the processing means may be adapted to incorporate data compression steps rather than readdressing each pixel at each frame. Pixels whose colour and intensity remain unaltered are therefore not addressed using the preferred processing means. This saves energy and increases speed of operation of the display device.
- a method of fabricating a liquid crystal device (10) including the steps of: a) forming a first array of electrodes on a first substrate; b) arranging a colour filter adjacent the first array of electrodes; c) forming a second array of electrodes on a second substrate; d) forming a display cell with the first and second substrates, the display cell having spacers to space the substrates, characterised in that liquid crystal material of the type which has memory and whose planar texture is arranged to reflect non-visible radiation, is introduced into the display cell.
- a method of fabricating a liquid crystal device (10) including the steps of: a) forming a colour filter on a first substrate; b) forming a first array of electrodes adjacent the colour filter; c) forming a second array of electrodes on a second substrate; d) forming a display cell with the first and second substrates, the display cell having spacers to space the substrates, characterised in that liquid crystal material of the type which has memory and whose planar texture is arranged to reflect non-visible radiation, is introduced into the display cell.
- the display cells may then be connected to drive means.
- the first array of electrodes is preferably formed by: a) depositing a layer of insulating material on a surface of the first substrate, b) depositing a layer of conductive material on the insulating layer, and c) etching at least a portion of the conductive material to form the electrode array.
- the layer of insulating material may be silicon dioxide, or other suitable material.
- the conductive material is preferably indium tin oxide (ITO).
- the second array of electrodes is preferably formed by: a) depositing a first layer of insulating material on a surface of the second substrate, b) depositing a second layer of material on a surface of the first layer of insulating material, b) depositing a layer of conductive material adjacent the second layer, and c) etching at least a portion of the conductive material to form the electrode array.
- the first insulating layer preferably includes silicon dioxide.
- the second layer of material preferably includes chromium, and the conductive layer is preferably formed from aluminium.
- a further layer of insulating material may be deposited on the first and/or second array of electrodes, and the surrounding surfaces. This insulating layer prevents electrical currents passing between the first and second electrode arrays.
- a layer of alignment material may be deposited on the insulating layer.
- the alignment layer may be buffed in order to align the liquid crystal material.
- Figure la shows a cross-sectional view of a liquid crystal display device according to a first embodiment of the invention
- Figure lb shows a cross-sectional view of a liquid crystal display device according to a second embodiment of the display device
- Figure 2a shows a cross-sectional view of part of an array of electrodes, showing column electrodes formed on a first substrate
- Figure 2b shows a perspective view of column electrodes formed on a first substrate
- Figure 3 a shows a cross-sectional view of a row of electrodes formed on a second substrate
- Figure 3b shows a perspective view of a row of electrodes formed on a second substrate
- Figures 4a and 4b show cross-sectional views of first and second portions of a display cell which is incorporated into an LCD device.
- liquid crystal display device 10 according to a first embodiment of the invention comprises a rear substrate 12 and a front substrate 14. An eye 16 is positioned adjacent the front substrate 14 to illustrate from which side a viewer sees the device 10.
- ITO Indium Tin Oxide
- Another ITO layer for example in the form of columns 20, is deposited on an inside surface of front glass substrate 14.
- the rows 18 and columns 20 together define an array of pixels (not shown).
- a reflective layer 22 is deposited on an inside surface of layer 18.
- the reflective layer 22 comprises one or more metallic layers which has/have a high reflectivity. Alternatively if the reflective layer is metallic (and therefore electrically conductive) layer 18 may be omitted and reflective layer 22 may act as a reflector and as an electrode.
- Colour filter (or colour mosaic) 24 is interposed between substrate 14 and the layer of Indium Tin Oxide 20.
- Colour filter 24 comprises parallel rows of closely spaced bars or columns of red, green and blue stripes. These stripes are in registration with the parallel columns 20 of Indium Tin oxide (ITO).
- ITO Indium Tin oxide
- FIG. la a cross-sectional view of a second embodiment of the invention is shown.
- a layer of silicon dioxide 30 is deposited on the inside surface of front glass substrate 14.
- An rTO layer 20 is formed on a surface of layer 30.
- a plurality of parallel electrodes 21 are formed by etching the ITO layer 20.
- Colour filter 24 is formed on a surface of electrodes 21.
- Colour filter 24 comprises parallel rows of red, green and blue stripes. These stripes are in registration with electrodes 21, as in the first embodiment of the invention.
- a layer of insulating material 60 such as silicon dioxide is deposited on the inside surface of rear glass substrate 12.
- a layer of chromium 32 is then deposited on the surface of insulating layer 60.
- a reflective layer of aluminium 22 is formed on the surface of layer 32.
- a plurality of electrodes are formed by etching the aluminium layer 22.
- the liquid crystal 15. contained between substrates 12 and 14 is of the stabilised cholesteric texture (SCT) type whose pitch has been adjusted to be greater than, or equal to. 0.5 ⁇ m.
- SCT stabilised cholesteric texture
- Such liquid crystal material 15 possesses the ability to be switched to several different stable states upon application of an electric field established by a switching voltage, (VI volts) across electrodes 18 and 21. Depending on the state of the liquid crystal 15 it may totally scatter or totally reflect incident radiation, or exist in a plurality (preferably at least sixteen) of states between these two extremes.
- a pixel (not shown) having the address row number p and column number q is to be switched to red by a driver (not shown).
- Row p and column q each receive a voltage which establishes a potential difference of VI volts and therefore an electric field across pixel (pq).
- Pixel (pq) is adjacent a red stripe of colour filter 24.
- Applying voltage waveform (VI) across ITO electrodes 18 and 21 produces the planar texture state in the liquid crystal material 15 and thus provides an optically transparent state to a viewer.
- Applying a second waveform (V2) produces a focal conic texture in the liquid crystal 15 which causes a highly scattering optical state.
- Waveforms having intermediate voltages VI and V2 provide a series of grey levels, i.e. states in which the level of scattering is lower than that produced by applying V2 but greater than that achieved by applying VI.
- each of these states (i.e. the optically clear, the strongly scattering and the intermediate grey levels) is stable at zero voltage. That is when the device is switched off and not consuming any energy, liquid crystal material remains in its switched state. Thus once switched a pixel in the display device 10 requires no energy. Hence, provided there is no change to the pixel colour, the field can be switched off (in respect of the pixel(s) concerned) and processing means may be provided for determining and achieving this. Such processing means acts to further reduce energy consumption as no energy is spent re-addressing pixels whose state does not change from one frame to the next, and which includes a liquid crystal material which exhibits memory. Also because no polarisers are used the display device 10 is relatively bright.
- the device 10 includes a display cell which is formed from two planar substrate portions, typically made from either sodalime or borosilicate glass.
- the first portion of the display cell includes column electrodes 21, for example, and a colour filter.
- the glass substrate 14 is first coated with a layer of silicon dioxide 30, and a layer of indium tin oxide 20 is deposited over the silicon dioxide layer.
- the electrodes 21 are formed by etching the indium tin oxide layer so that the required areas of silicon dioxide 30 are revealed, as shown in Figure 2.
- the electrodes are etched using well-known photolithographic and selective etching techniques.
- the colour filter 24 is formed by depositing pigmented substances on the electrodes, and selectively removing portions of the substances using photolithographic techniques. Before the colour filter is deposited on the electrodes, a black matrix may be deposited on the ITO electrodes and the exposed areas of silicon dioxide. The black matrix is then etched from the ITO electrodes, leaving a thin coating of the matrix previously exposed areas of silicon dioxide. However, it is sometimes advantageous to place the colour filters underneath the ITO electrodes in order to avoid a drop in voltage across the colour filter.
- the second portion of the display cell includes row electrodes, for example, and a reflective layer.
- the second portion of the display device is formed by depositing a thin layer of chromium 32 followed by a layer of aluminium 33. Layer 32 is required as aluminium does not easily adhere to glass.
- the electrodes of the first portion of the display cell are formed by etching the aluminium layer 33 in order to produce a row electrode pattern, as shown in Figure 3. If the glass used is sodalime, then it is necessary to have an insulating layer of silicon dioxide between the chromium layer and the glass. This prevents the migration of ions from the glass into the liquid crystal material.
- Both portions of the display cell are then coated with a barrier layer 34 formed from a spin-on-glass of vacuum deposited silicon dioxide.
- the barrier layer 34 prevents electrical shorts between row and column electrodes.
- Layer 34 is subsequently coated with a surface alignment layer 36 being formed by spin coating, roller coating, or other suitable printing technique.
- the surface alignment material used is a polyimide such as AL5417 which is available from Japan Synthetic Rubber. After deposition, the polyimide is dried, cured and then rubbed (buffed) in order to align the liquid crystal material which is to be added at a later stage of fabrication.
- the first and second portions of the display cell having layers 34 and 36 are illustrated by Figures 4a and 4b, respectively.
- Both portions of the display cell are now ready to be assembled.
- An edge seal material for example XN5AC produced by Mitsui, is now deposited around the periphery of the first portion of the display cell. A small gap is left in the edge seal material in order to form a fill hole.
- Spacer material is deposited on the surface of the second portion of the display cell by, for example, spraying a mixture of spacer balls and a solvent. The spacer balls used are typically 6 micrometres in diameter, and are available from Nagase.
- the display cell is then assembled by applying heat and pressure to the two separate portions.
- Liquid crystal material 15 is then introduced into the display cell by vacuum filling.
- the liquid crystal material used in this example is a mixture of a nematic liquid crystal mixed with chiral dopant such that the mixture has a cholesteric pitch of greater than, or equal to, 0.5 micrometres.
- a nematic crystal such as ZLI 2222-100 and chiral dopant CB15 supplied by Merck may be used.
- the cell is subjected to external pressure in order to force the glass portions to rest on the spacers. Under applied external pressure, excess liquid crystal material escapes from the display cell via the fill hole. This excess liquid crystal material is removed from the fill hole, and the fill hole is plugged with, for example a UV curable adhesive such as NorlandTM 63.
- the display cell may now be connected to respective drive means via electrical contacts
- SCT material may be replaced by Smectic-A material.
- the invention may be incorporated into many items such as hand-held computer games, wrist-watches, laptop or palmtop computers, pocket calculators, personal organisers and camcorders. It may even be used in advertising.
- the display device may be incorporated into packaging, or even attached to shopping trolleys (carts) to show advertisements or to convey other information to a customer.
- RF receiver may permit in-store broadcasts or advertisements to be transmitted simultaneously to all trolleys, thereby bringing to the attention of customers information such as special offers.
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2000521412A JP2001523840A (en) | 1997-11-14 | 1998-11-16 | Liquid crystal display device and manufacturing method thereof |
EP98954607A EP1060436A1 (en) | 1997-11-14 | 1998-11-16 | A liquid crystal display device and method of fabrication |
AU11662/99A AU1166299A (en) | 1997-11-14 | 1998-11-16 | A liquid crystal display device and method of fabrication |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GBGB9724142.6A GB9724142D0 (en) | 1997-11-14 | 1997-11-14 | A liquid crystal display device |
GB9724142.6 | 1997-11-14 |
Publications (1)
Publication Number | Publication Date |
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WO1999026107A1 true WO1999026107A1 (en) | 1999-05-27 |
Family
ID=10822122
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1998/003446 WO1999026107A1 (en) | 1997-11-14 | 1998-11-16 | A liquid crystal display device and method of fabrication |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP1060436A1 (en) |
JP (1) | JP2001523840A (en) |
AU (1) | AU1166299A (en) |
GB (1) | GB9724142D0 (en) |
TW (1) | TW434439B (en) |
WO (1) | WO1999026107A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8854589B2 (en) | 2008-06-18 | 2014-10-07 | 3M Innovative Properties Company | Conducting film or electrode comprising a dielectric intervening layer having electrically conductive pathways disposed between first and second transparent or semi-transparent conductive layers |
US9581870B2 (en) | 2009-08-13 | 2017-02-28 | 3M Innovative Properties Company | Conducting film or electrode with improved optical and electrical performance for display and lighting devices and solar cells |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5437811A (en) * | 1991-05-02 | 1995-08-01 | Kent State University | Liquid crystalline light modulating device and material |
US5493430A (en) * | 1994-08-03 | 1996-02-20 | Kent Display Systems, L.P. | Color, reflective liquid crystal displays |
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1997
- 1997-11-14 GB GBGB9724142.6A patent/GB9724142D0/en not_active Ceased
-
1998
- 1998-11-16 WO PCT/GB1998/003446 patent/WO1999026107A1/en not_active Application Discontinuation
- 1998-11-16 AU AU11662/99A patent/AU1166299A/en not_active Abandoned
- 1998-11-16 EP EP98954607A patent/EP1060436A1/en not_active Withdrawn
- 1998-11-16 JP JP2000521412A patent/JP2001523840A/en active Pending
- 1998-11-21 TW TW087119335A patent/TW434439B/en not_active IP Right Cessation
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5437811A (en) * | 1991-05-02 | 1995-08-01 | Kent State University | Liquid crystalline light modulating device and material |
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US8854589B2 (en) | 2008-06-18 | 2014-10-07 | 3M Innovative Properties Company | Conducting film or electrode comprising a dielectric intervening layer having electrically conductive pathways disposed between first and second transparent or semi-transparent conductive layers |
US9402305B2 (en) | 2008-06-18 | 2016-07-26 | 3M Innovative Properties Company | Transparent conducting article comprising first and second conductive layers and an intervening inorganic dielectric layer having a plurality of apertures therein |
US9581870B2 (en) | 2009-08-13 | 2017-02-28 | 3M Innovative Properties Company | Conducting film or electrode with improved optical and electrical performance for display and lighting devices and solar cells |
US10114257B2 (en) | 2009-08-13 | 2018-10-30 | 3M Innovative Properties Company | Conducting film or electrode with improved optical and electrical performance for display and lighting devices and solar cells |
Also Published As
Publication number | Publication date |
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JP2001523840A (en) | 2001-11-27 |
GB9724142D0 (en) | 1998-01-14 |
TW434439B (en) | 2001-05-16 |
AU1166299A (en) | 1999-06-07 |
EP1060436A1 (en) | 2000-12-20 |
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