WO2006038404A1 - Lcd comprising backlight and reflective polarizer on front panel - Google Patents
Lcd comprising backlight and reflective polarizer on front panel Download PDFInfo
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- WO2006038404A1 WO2006038404A1 PCT/JP2005/016166 JP2005016166W WO2006038404A1 WO 2006038404 A1 WO2006038404 A1 WO 2006038404A1 JP 2005016166 W JP2005016166 W JP 2005016166W WO 2006038404 A1 WO2006038404 A1 WO 2006038404A1
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- liquid crystal
- crystal display
- display according
- polarizer
- reflective polarizer
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/3406—Control of illumination source
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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
- G02F1/133—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
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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
- G02F1/133—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
- G02F1/133536—Reflective polarizers
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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
- G02F1/133—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
- G02F1/133545—Dielectric stack polarisers
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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
- G02F1/133—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
- G02F1/133562—Structural association of cells with optical devices, e.g. polarisers or reflectors characterised by the placement of the optical elements on the viewer side
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/06—Adjustment of display parameters
- G09G2320/0626—Adjustment of display parameters for control of overall brightness
- G09G2320/0646—Modulation of illumination source brightness and image signal correlated to each other
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2360/00—Aspects of the architecture of display systems
- G09G2360/14—Detecting light within display terminals, e.g. using a single or a plurality of photosensors
- G09G2360/145—Detecting light within display terminals, e.g. using a single or a plurality of photosensors the light originating from the display screen
Definitions
- the present invention relates to the field of data display devices. More specifically, this invention relates to liquid crystal displays with backlight systems possessing improved optical characteristics and decreased optical losses.
- Flat panel displays or liquid crystal displays (LCDs) are popular display devices for conveying information generated by computers. Reduced weight and size of a flat panel display offer great advantages over cathode ray tube (CRT) displays.
- High-quality flat panel displays are typically backlighted, that is, a source of illumination is placed behind the LCD layers to facilitate visualization of the image.
- Flat panel LCD devices are used in many applications including the computer industry, where flat panel LCD units are an excellent display choice for laptop computers and other portable electronic devices. However, because of rapid progress in the technology of flat panel LCDs, these devices find increasing use in other mainstream applications such as desktop computers, high-end graphics computers, and television and other multimedia monitors.
- a liquid crystal display typically comprises a pair of plates with driving electrodes and a layer of twist nematic (TN) or supertwist nematic (STN) liquid crystal material confined between these plates.
- the liquid crystal layer thickness and anisotropy are such that it is capable of rotating polarization of a normally incident ray of light for at least one wavelength in the visible spectrum by about 80-100° (for TN) or 180-230° (for STN).
- the device further comprises a rear light-entrance polarizer having a transmission axis oriented in a certain direction, a front light-exit polarizer having a transmission axis oriented in a direction different from the former one, thereby defining a normally white or normally black display, and a backlight system.
- the device may also comprise a rear retardation film situated between the rear polarizer and the twisted nematic liquid crystal layer, and a front retardation film situated between the front polarizer and the liquid crystal layer.
- a picture on the display is formed by thousands of small imaging elements, or "pixels”, which are either “on”, “off”, or “partially on”.
- An image is displayed usually by applying an electric field to the individual pixels.
- a twist nematic (TN) LCD if a particular pixel is "on”, then the phase and thus the polarization of a linearly polarized light ray will remain unchanged as it passes through the pixel. However, if the pixel is "off, then the polarization plane of the light ray will be rotated, that is, its phase will be modulated so that its polarization angle is changed by 90°. If the pixel is "partially on”, then the ray polarization axis will be rotated by less than 90°.
- An “on” pixel can be designated to represent either black or white. If the "on” pixel is designated as black, then the “off pixel is designated as white, and vice versa.
- a “partially on” pixel represents a shade of gray.
- Polarizers are provided on the LCD so that the polarization state of light passing through a pixel is converted into an appropriate amount of transmission (black, white, or gray).
- STN supertwist nematic
- the "off pixel will have a blue color, while the “on” pixel will be cream colored. If the "yellow mode” is used, the “off pixel will be yellow and the “on” pixel will be blue-gray.
- a film may be added between the STN LCD and one of its polarizers to neutralize the display color, that is, to convert the color display into a black-and-white display.
- the flat panel LCD is typically provided with a backlight system.
- the backlight system radiates at least partly polarized light.
- the most effective system capable of converting all the nonpolarized incident light flux of backlight system into polarized light with minimum losses is offered by the so-called optical recycling scheme with a reflective polarizer.
- the reflective polarizer usually comprises a multilayer structure consisting of alternating anisotropic and isotropic layers, with the refractive index of an isotropic layer being equal to that of one of the anisotropic layers. This structure is capable of transmitting light in one polarization state while reflecting light polarized in the perpendicular direction.
- the reflected polarized light passes through a quarter-wave plate, changes the polarization direction, reflects from a mirror, and enters the reflective polarizer again, this time in the first polarization state.
- the reflective polarizer is placed on the backlight system or on the rear plates of the LCD.
- birefringent (or reflective) polarizers Many naturally occurring crystalline compounds act as birefringent (or reflective) polarizers.
- calcite (calcium carbonate) crystals possess well-known birefringent properties.
- single crystals are expensive materials and cannot be readily formed into the desired shapes or configurations, which are required for particular applications.
- birefringent polarizers were fabricated (see, e.g., Makas, U.S. Patent No. 3,438,691) from plate-like or sheet-like birefringent polymers such as poly(ethylene terephthalate) incorporated into an isotropic polymer matrix.
- polymers can be oriented by uniaxial stretching so as to align the polymer chains on a molecular level as described by Rogers et al., U.S. Patent No. 4,525,413.
- Multilayer optical devices comprising alternating layers of highly birefringent polymers and isotropic polymers with large refractive index mismatch have been also proposed by Rogers et al.
- these devices require the use of specific highly birefringent polymers obeying certain mathematical relationships between their molecular configurations and electron density distributions.
- birefringent interference polarizer in the form of a multilayer sheet or film, which can be fabricated from readily available materials using well-established coextrusion techniques.
- the layers can be made of alternating birefringent and isotropic materials.
- one of the two indices of refraction of the birefringent material substantially matches the index of refraction of the isotropic material in the adjacent layer, or the alternating layers can be made of two different birefringent materials selected so that the lower of the two indices of refraction of one of the materials substantially matches the higher of the two indices of refraction of the other material.
- the layers should have an optical thickness equal to one-quarter of the selected light wavelength.
- an LCD containing a reflective polarizer on the rear panel which represents a multilayer structure containing anisotropic layers made of the same materials.
- Examples of diffusely reflecting polarizing materials are described in U.S. Patent Nos. 5,783,120 and 5,825,543 and in PCT Patent Application Publication Nos. WO 97/32223, WO 97/32224, WO 97/32225, WO 97/32226, WO 97/32227, and WO 97/32230.
- Examples of multilayer reflective polarizers are described in U.S. Patent No. 5,882,774.
- Examples of cholesteric reflective polarizers are described in EP No. 606,940 and U.S. Patent No. 5,325,218.
- the objectives of the disclosed invention are to decrease optical losses in LCD displays and to reduce heating of large displays, for example, displays for home TV appliances.
- the Liquid Crystal Display according to the present invention forms an image consisting of pixels occurring in either "on" or “off states.
- the liquid crystal display comprises a liquid crystal cell formed by front and rear panels with polarizing means on each of them, and a backlight system comprising a light source and a reflector.
- the polarizing means on the front panel include a reflective polarizer and a dichroic polarizer, wherein transmittance axes of both polarizers coincide and the dichroic polarizer is placed on top of the reflective polarizer.
- the LCD comprises a feedback system.
- the brightness of the light source is changed so as to be proportional to the number of "on" pixels of the image, which is provided by the feedback system.
- the reflective polarizer is a multilayer stack of layers. Each pair of adjacent layers is characterized by matched refractive indices in one direction in the plane of the reflective polarizer and by substantially different refractive indices in the perpendicular direction. To reach an extremely high efficiency previously mentioned, the layers have an optical thickness of one- quarter of a selected light wavelength.
- Figure 1 is a cross section of the liquid crystal display according to the present invention.
- Figure 2 demonstrates a light propagation in the LCD according to the present invention.
- Figure 3 is a cross section diagram of another LCD according to the present invention.
- Figure 4 is a partial cross section of the front panel of the color LCD according to the present invention.
- Figure 5 is a partial cross section of the front panel of another color LCD according to the present invention.
- Figure 6 is a partial cross section of the front panel of another, color LCD according to the present invention.
- Figure 7 is a partial cross section of the TN LCD with a 90° twist according to the present invention and feedback system for controlling the brightness of the light source.
- Figure 1 shows a cross section of the LCD that comprises a liquid crystal cell 1, formed by front panel 2 and rear panel 3 with polarizing means on each of them, and a backlight system 4.
- a layer of liquid crystal 5 is placed between said panels.
- the polarizing means of the front panel include a reflective polarizer 6 and a dichroic polarizer 7 applied on top of the reflective polarizer.
- the transmission axes of both said polarizers coincide.
- the rear panel comprises a linear polarizer 8 of any type.
- the backlight system is an optical cavity of the edge backlight type, which includes a lamp 9 in a reflective lamp housing 10. The light emitted by the lamp is fed to a light guide 11 where it propagates until encountering a diffuse reflective structure, or layer 12 such as a spot array.
- This discontinuous array of spots is arranged to reflect the light and direct it toward the liquid crystal cell. Ambient light entering the optical cavity may also strike a spot or escape from the light guide through the interstitial areas between spots.
- the diffusely reflective layer 12 is positioned below the light guide to intercept and reflect light rays. In the general case, all the rays that emerge from the optical cavity are incident on the liquid crystal cell.
- the backlight system comprises an assembly of light sources representing, for example, a set of luminescent lamps or a LED matrix.
- a reflector placed behind the backlight system provides for a more effective use of the radiation source.
- the reflector can be of any type - specular or diffusive.
- the backlight system may further comprise an additional optical element that serves as a light collimator, for example, an assembly of prisms. This element performs the light collimator function by transmitting rays normal to the plane of the backlight system and simultaneously increases the degree of polarization of the transmitted light.
- the backlight system is also provided with an additional dichroic polarizer placed at the system output or applied on the panel of the LCD.
- a device comprising an anisotropic fluorescent thin crystal film (AF TCF), applied to the surface of at least one element of the backlight system between the light source and the system output.
- Said AF TCF is formed by means of Cascade Crystallization Process as described below.
- the light sources for the backlight for such a system can represent low- or high-pressure gas-discharge lamps, including those possessing a band spectrum, for example Hg, H, Xe lamps, and other similar lamps ; high- and ultralow-pressure arc discharge lamps; pulsed plasma discharge lamps; luminescent sources; and any other sources used in similar systems. These light sources usually exhibit at least one intense emission peak in the wavelength range between 260 and 450 nm.
- the AF TCF is selected so as to provide that the film material possesses a luminescence excitation spectrum with a band corresponding to the above peak in the source emission spectrum.
- the AF TCF can be colorless (transparent) or colored (absorbing) in the visible spectral range. In the latter case, the film may, depending on the particular optical properties, perform the function of retarding or polarizing the visible light simultaneously with the main function of emitting polarized light.
- the film material can be selected so that AF TCF will emit polarized light within a sufficiently narrow spectral interval.
- Such films can be used for creating sources of polarized color light, in particular, for color matrices to be used in the backlight systems of color LCDs. Using the backlight system with AF TCF provides for obtaining polarized light on liquid crystal cell and for increasing the light yield at the expense of reduced absorption losses in the internal elements of the system.
- a reflective polarizer is placed on the front panel of the LCD.
- This reflective polarizer comprises a multilayer stack made of materials substantially in the working region of the LCD.
- Each pair of adjacent layers is characterized by matched refractive indices in one direction in the plane of the reflective polarizer and by substantially different refractive indices in the perpendicular direction.
- said layers have an optical thickness of one-quarter of the wavelength of light polarized in the direction of the refractive index difference between the adjacent layers.
- At least one layer in each pair is made of a biaxial material with negative birefringence, which has a crystal structure formed by at least one polycyclic organic compound with a conjugated ⁇ -system of bonds and an intermolecular spacing of 3.4 ⁇ 0.3 A is in the direction of one of the optical axes.
- This material has suitable optical properties comprising a high degree of anisotropy (not less than 0.4) and a large value of the refractive index in at least one direction (greater than 2.2).
- the material has good technological properties.
- a necessary condition is the presence of a developed system of ⁇ -conjugated bonds between conjugated aromatic rings of the molecules and the presence of groups (such as amine, phenol, ketone, etc.) lying in the plane of the molecule and involved into the aromatic system of bonds.
- the molecules and/or their molecular fragments possess a planar structure and are capable of forming supramolecules in solutions.
- Another necessary condition is the maximum overlap of ⁇ -orbitals in the stacks of supramolecules. The material is selected taking into account its spectral characteristics.
- the material formed from an acenaphtho[l,2-b]quinoxaline sulfoderivative is well suited for these aims, although this material is presented here as one of examples and the materials which might be used for present invention are not limited by using only this compound.
- X and Y are individually selected from the group consisting of CH 3 , C 2 H 5 , OCH 3 , OC 2 H 5 , Cl, Br, OH, and NH 2 ;
- M is a counter ion; and j is the number of counter-ions in the molecule.
- TCF thin crystal film
- Said TCF can be obtained by method called Cascade Crystallization Process developed by Optiva, Inc. [see for example P. Lazarev and M. Paukshto, Proceedings of the 7th International Workshop “Displays, Materials and Components” (Kobe, Japan, November 29-December 1, 2000), pp. 1159-1160].
- an organic compound dissolved in an appropriate solvent forms a colloidal system (lyotropic liquid crystal solution) in which molecules are aggregated into supramolecules constituting kinetic units of the system.
- This liquid crystal phase is essentially a precursor of the ordered state of the system, from which a solid anisotropic crystal film (called thin crystal film, TCF) is formed in the course of subsequent alignment of the supramolecules and removal of the solvent.
- Another layer of each pair in the multilayer-stack of the reflective polarizer can be made from a suitable lacquer or polymer.
- the reflective polarizer manufactured as described above does not require big number of layers, it also possesses a small thickness, and a high polarizing efficiency.
- Functioning of the disclosed LCD consists in controlled variation of the state of individual pixels.
- Figure 2 illustrates the propagation of light through the display 1. For example, in a 90° TN LCD (Fig. 2), if a particular pixel is "on”, then the phase and thus the polarization (polarization mode - a), of a linearly polarized light ray will remain unchanged as it is transmitted through the pixel.
- the polarization plane of light will be rotated (polarization mode - b), that is, its phase will be modulated so that its polarization angle will change by 90°, and the ray will be reflected from the reflective polarizer 6.
- This light ray again passes through the liquid crystal layer 5 and strikes the diffuse reflector 12.
- This light is depolarized (polarization mode - a+b) and re-directed to the liquid crystal cell through this pixel and the rest of pixels. If the pixel is "partially on”, then the light ray will be rotated by less than 90°.
- An "on" pixel can be designated to represent either black or white.
- the "on" pixel is designated as black, then the "off pixel is designated as white, and vice versa.
- a "partially on” pixel represents a shade of gray.
- Polarizers are then provided on the LCD so that the polarization state of the light passing through the pixel is converted into the appropriate amount of transmission (black, white, or gray).
- the light reflected by the interference reflective polarizer is transmitted through the "on” pixel, which increases the LCD brightness. In this way, the power of the light source may be decreased in proportion to the number of "on” pixels of an image displayed on the LCD.
- the multiple light recirculation effected by the combination of the optical cavity and the reflective polarizer offers an efficient mechanism for converting light from state (b) to state (a) and allocation among "on” pixels for ultimate transmission to the viewer.
- Liquid crystal displays according to the present invention may have some functional elements made in different variants.
- the exemplary embodiment in Figure 3 shows the rear- panel polarizer comprising a combination of dichroic 13 and reflective 14 polarizers with parallel optical axes.
- the LCD can be provided with an optional antiglare coating 15.
- the LCD employing super twist nematic liquid crystal comprises a reflective polarizer on the front panel comprising a matrix of colored reflecting elements, each reflecting light in at least a part of the aforementioned spectral region.
- the colors are blue (with wavelengths in the range 400-500 nm), green (500-600 am), and red (600-700 nm).
- FIGs 4-6 show different variants of the front panel with a color absorbing filter.
- the front panel comprises broadband reflective polarizer 16, broadband dichroic polarizer 17 and an array of color elements (color filter 18) confined between the two polarizers.
- the matrix of color elements is situated between reflective polarizer 16 and front panel 2.
- the combination of the broadband dichroic polarizer 17 and color filter 18 provides for an increase in the contrast and eliminates flare spots as described above for monochrome LCDs.
- reflective polarizer 20 comprises an array of color reflecting elements. This polarizer is a multilayer structure composed of elements selected so as to transmit light in a certain spectral interval. In an LCD with such a reflective polarizer, the color filter possesses the corresponding shapes and colors of elements. This filter is situated between the reflective polarizer 20 and the dichroic polarizer 17.
- the Liquid Crystal Display forms an image consisting of pixels occurring in either "on" or "off" states.
- the liquid crystal layer 71 is sandwiched between a pair of crossed polarizers 72 and 73.
- the polarizer 72 is aligned so that the transmission axis is parallel to the director at the input end of the liquid crystal.
- the analyzer 73 - reflective polarizer - is also aligned so that the transmission axis is parallel to the director at the exit end of the liquid crystal. This is known as the normally white (NW) configuration.
- NW normally white
- the inner surfaces of the panels are deposited with transparent electrodes 74 and 75 made of conductive coatings of indium tin oxide (ITO).
- ITO indium tin oxide
- the liquid crystal cell should be electrically addressed.
- the electrically addressing is achieved by using multiplexing techniques.
- the liquid crystal display according to the present invention further comprises a feedback system for controlling the brightness of the light source 76.
- the LCD according to the present invention deals with field of "lossless" devices. If the pixel is "off", the corresponding light will be reflected rearward and after redistribution in the device it will be irradiated cross the pixel which is "on”. The brightness of light parts of image will be increased. It is necessary to decrease the total brightness of the light source so as to viewer do not see any changes in brightness and in color of the image. The brightness of the light source will be changed proportional to the number of pixels in the "on” state (or inversely to the number of pixels in the "off state). The control of this process is realized by the feedback system.
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Abstract
Description
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Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
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JP2007511559A JP4451485B2 (en) | 2004-10-01 | 2005-08-29 | LCD with backlight and reflective polarizer on front panel |
EP05776925A EP1794644A4 (en) | 2004-10-01 | 2005-08-29 | Lcd comprising backlight and reflective polarizer on front panel |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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US10/956,393 | 2004-10-01 | ||
US10/956,393 US7733443B2 (en) | 2004-03-09 | 2004-10-01 | LCD comprising backlight and reflective polarizer on front panel |
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WO2006038404A1 true WO2006038404A1 (en) | 2006-04-13 |
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PCT/JP2005/016166 WO2006038404A1 (en) | 2004-10-01 | 2005-08-29 | Lcd comprising backlight and reflective polarizer on front panel |
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US (1) | US7733443B2 (en) |
EP (1) | EP1794644A4 (en) |
JP (1) | JP4451485B2 (en) |
KR (1) | KR100869015B1 (en) |
CN (1) | CN100424562C (en) |
WO (1) | WO2006038404A1 (en) |
Cited By (4)
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JP2008090216A (en) * | 2006-10-05 | 2008-04-17 | Nitto Denko Corp | Polarizing plate and liquid crystal display |
JP2013145404A (en) * | 2013-04-09 | 2013-07-25 | Nitto Denko Corp | Polarizing plate and liquid crystal display device |
US8792164B2 (en) | 2011-02-10 | 2014-07-29 | Lg Chem, Ltd. | Polarizing plate, fabrication method thereof, and display device using the same |
JP2015028661A (en) * | 2014-10-16 | 2015-02-12 | 日東電工株式会社 | Polarizing plate and liquid crystal display device |
Families Citing this family (26)
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US7045177B2 (en) * | 2003-11-21 | 2006-05-16 | Nitto Denko Corporation | Sulfoderivatives of acenaphtho[1,2-b]quinoxaline, lyotropic liquid crystal and anisotropic film on their base |
US7733443B2 (en) | 2004-03-09 | 2010-06-08 | Nitto Denko Corporation | LCD comprising backlight and reflective polarizer on front panel |
US7456915B2 (en) * | 2004-03-26 | 2008-11-25 | Nitto Denko Corporation | Liquid crystal display panel with broadband interference polarizers |
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Also Published As
Publication number | Publication date |
---|---|
JP4451485B2 (en) | 2010-04-14 |
US7733443B2 (en) | 2010-06-08 |
CN100424562C (en) | 2008-10-08 |
KR100869015B1 (en) | 2008-11-17 |
KR20070064351A (en) | 2007-06-20 |
EP1794644A4 (en) | 2009-03-25 |
US20050200771A1 (en) | 2005-09-15 |
CN101036081A (en) | 2007-09-12 |
JP2008512693A (en) | 2008-04-24 |
EP1794644A1 (en) | 2007-06-13 |
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