EP2179323A1 - Rétroéclairage de dispositif d'affichage à cristaux liquides comportant une combinaison del-luminophores - Google Patents

Rétroéclairage de dispositif d'affichage à cristaux liquides comportant une combinaison del-luminophores

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Publication number
EP2179323A1
EP2179323A1 EP08774036A EP08774036A EP2179323A1 EP 2179323 A1 EP2179323 A1 EP 2179323A1 EP 08774036 A EP08774036 A EP 08774036A EP 08774036 A EP08774036 A EP 08774036A EP 2179323 A1 EP2179323 A1 EP 2179323A1
Authority
EP
European Patent Office
Prior art keywords
phosphor
emitting
red
light source
liquid crystal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP08774036A
Other languages
German (de)
English (en)
Inventor
Holger Winkler
Thomas Juestel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Merck Patent GmbH
Original Assignee
Merck Patent GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Merck Patent GmbH filed Critical Merck Patent GmbH
Publication of EP2179323A1 publication Critical patent/EP2179323A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/67—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing refractory metals
    • C09K11/68—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing refractory metals containing chromium, molybdenum or tungsten
    • C09K11/685—Aluminates; Silicates
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
    • C09K11/7728—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing europium
    • C09K11/77342—Silicates
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
    • C09K11/7766—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals
    • C09K11/7774—Aluminates
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
    • C09K11/7783—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals one of which being europium
    • C09K11/7794—Vanadates; Chromates; Molybdates; Tungstates
    • 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
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133603—Direct backlight with LEDs
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/12—Light sources with substantially two-dimensional radiating surfaces
    • H05B33/14—Light sources with substantially two-dimensional radiating surfaces characterised by the chemical or physical composition or the arrangement of the electroluminescent material, or by the simultaneous addition of the electroluminescent material in or onto the light source
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0066—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form characterised by the light source being coupled to the light guide
    • G02B6/0073—Light emitting diode [LED]
    • 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
    • G02F1/1336—Illuminating devices
    • G02F1/133614—Illuminating devices using photoluminescence, e.g. phosphors illuminated by UV or blue light
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making

Definitions

  • the invention relates to a liquid crystal display with a background lighting system with a white light source, which comprises a semiconductor diode and a phosphor layer of a combination of at least two
  • the invention relates to a backlight system and its manufacturing method.
  • Liquid crystal displays are passive display systems, i. they do not shine themselves. These indications are based on the principle that light passes or does not pass through the layer of liquid crystals. This means that an external light source is needed to create an image.
  • reflective liquid crystal displays the ambient light is used as an external light source, so they basically do without backlighting.
  • transmissive liquid crystal displays light is generated in a backlight system.
  • transflective liquid crystal displays transmissive and reflective at the same time
  • Each pixel is subdivided into a reflective and a transmissive subpixel whose associated liquid crystal layer thicknesses are approximately in the ratio 1: 2.
  • the reflective part operates with ambient light and has a reflective substrate layer, e.g. made of aluminium.
  • primary colors of the pixels can be generated by using white light from the backlight with the help of filtered by color filters eg into the primary colors blue, green and red.
  • the color gamut, which is important for the color representation, which the display can produce is limited by the purity of the blue, green and red primary colors.
  • Transferred to a CIE xy color chart, the red, green and blue primary colors of the display span a triangle indicating the color space that can be displayed by the display. Colors outside this color space can not be displayed by the display.
  • each pixel of the screen consists of red, green, and blue areas.
  • the colors of these areas are generated by the transmission of the white light of the backlight through a color filter array.
  • the color filters are partly responsible for the color space of the display.
  • CCFLs CoId Cathode Fluorescent Lamps
  • xenon discharge lamps which emit a wide range of colors with levels of unwanted color, such as light emitting diodes. As orange, yellow and cyan.
  • CCFLs CoId Cathode Fluorescent Lamps
  • xenon discharge lamps which emit a wide range of colors with levels of unwanted color, such as light emitting diodes. As orange, yellow and cyan.
  • To maximize the displayable color space of the screen only pure red, green and blue are needed.
  • the primary colors must be saturated because the white light of the primary light source is broken down into the primary colors by the color filters.
  • Brightness of the screen is reduced.
  • the CCFLs leading to a limited color space and the necessary additional complex color filters for reduced screen brightness have therefore recently been substituted by LED arrays. These arrays consist of blue, green and red LEDs that emit a much narrower band compared to CCFLs. For this reason, the displayable color space of the display is larger and the achievable brightness higher because only simple color filters are needed.
  • Other advantages that result are the higher energy efficiency of the display, because the backlight transmittance is significantly higher for LEDs (70%) than for CCFLs (5%).
  • LED backlights have a significantly longer life than CCFLs (100,000 operating hours for LEDs vs. 5000 operating hours for CCFLs), and LEDs do not use mercury, which is essential in CCFLs.
  • the disadvantage of using backlit blue, green and red LEDs is that the semiconductor chips of LEDs are different: InGaN for blue light, InGaN for green light (but with higher In content) and red Light is used in InGaAIP as a material basis. These three materials show different efficiencies for the emission of light and exhibit different degradation behaviors. As a consequence, an elaborate active control must be used which keeps the color point of the white light composed of the blue, green and red LEDs constant via control circuits which intervene in the LED control.
  • WO 02/095791 describes a liquid crystal panel equipped with a gas discharge lamp (cold cathode lamp or Xe discharge lamp) as a white light source containing a phosphor layer with a combination of phosphors emitting red, green and blue light.
  • a gas discharge lamp cold cathode lamp or Xe discharge lamp
  • the object of the present invention was to provide a backlight system which has the same high quality
  • the present invention thus provides a liquid crystal display equipped with at least one backlight system having at least one white light source, which contains at least one semiconductor diode, preferably emitting blue, and at least one phosphor layer comprising a combination of at least two phosphors, wherein at least one phosphor is red light and at least one phosphor emits green light.
  • a liquid crystal display usually has a liquid crystal unit and a backlight system.
  • the liquid crystal unit typically comprises a first and a second polarizer and a liquid crystal cell having two transparent layers, each carrying a matrix of light-transmissive electrodes. Between the two substrates, a liquid crystal material is arranged.
  • the liquid crystal material includes, for example, TN (twisted nematic) liquid crystals, super twisted nematic (STN) liquid crystals, double super twisted nematic (DSTN) liquid crystals, foil super twisted nematic (FSTN) liquid crystals, vertically alligned liquid crystals (VAN) or OCB (optically compensated bend) liquid crystals.
  • TN twisted nematic
  • STN super twisted nematic
  • DSTN double super twisted nematic
  • FSTN foil super twisted nematic
  • VAN vertically alligned liquid crystals
  • OCB optically compensated bend
  • the electrodes in the electric field, the liquid crystal molecules are switched, only on one side of the liquid crystal layer.
  • the resulting electric field is inhomogeneous and aligned in a first approximation parallel to the substrate surface.
  • the molecules are correspondingly switched in the substrate plane (in plane), which in comparison to TN
  • a further subject of the present invention is a backlight system with a white light source, which contains a semiconductor diode, preferably emitting in the blue, and a phosphor layer comprising a combination of at least two phosphors which emit red and green light.
  • the backlight system according to the invention can be, for example, a "Direct Lif backlight system (see FIG. 1) or a" side lit “backlight system (see FIG. 2), which has a light guide and a coupling-out structure.
  • the backlight system has a white light source, which is usually located in a housing, which preferably has a reflector on the inside.
  • the backlight system may further include at least one diffuser plate.
  • the liquid crystal unit is provided with a color filter.
  • the color filter contains mosaic patterned pixels that pass either red, green, or blue light.
  • the color filter is preferably arranged between the first polarizer and the liquid crystal cell.
  • this is an InGaN semiconductor diode which, in conjunction with corresponding conversion luminescent substances, preferably emits white or almost white light.
  • This InGaN semiconductor diode has an emission maximum between 430 nm and 480 nm and has a very high efficiency and long life (> 150,000 hours) with only a very low degradation of the efficiency.
  • the white light source may also be a luminescent compound based on ZnO, TCO, ZnSe or SiC. Basically, for a blue-emitting semiconductor diode, which in
  • the white light source according to the invention has a phosphor layer with a combination of red and green emitting phosphors.
  • the green-emitting phosphors which are excited by the blue-emitting primary light source have emission maxima between 520 and 550 nm.
  • all cerium (III) or europium (II) -activated phosphors which are selected from the group of thiogallates are preferred , Silicates, oxonitridosilicates, aluminates, nitrides or garnets. Examples of these phosphors are here (Y 1 Lu) 3 (Al 1 Ga) 5 Oi 2 : Ce; SrSi 2 N 2 O 2 : Eu; SrGa 2 S 4 : Eu; (Sr, Ba) 2 SiO 4 : Eu and SrAl 2 O 4 : Eu.
  • the red emitting phosphors which are preferably line emitters, are excited either by the blue emitting primary light source or by the green emitting phosphor.
  • the red-emitting phosphors are preferably europium (III) or chromium (III) -activated line emitters. According to the invention, they have either an emission maximum between 590 and 620 nm (in the case of Eu (I I l) -activated phosphors) or a maximum between 680 and 700 nm (in the case of
  • the phosphor layer particularly preferably contains, as the red-emitting phosphor, a europium or chromium activated line emitter selected from the group AI 2 O 3 : Cr, Nao.5Gdo.3Euo.2WO4, Nao. 5 Yo.4Euo.iMo ⁇ 4, Nao.5Lao.3Euo.2WO4, Nao.5Lao. 3 Euo.2MoO 4 , Nao.5La o . 3 Euo.2 (WO 4 ) o.5 (MoO 4 ) o.5.
  • La- ⁇ .2Eu 0 .8MoO 4
  • Al 2 O 3 : Cr (ruby) is efficiently excited in the yellowish-green region of the spectrum to emit a deep red line at 693 nm.
  • Eu (III) activated phosphors can be used if a matrix is used which (partially) removes the ban on europium's inner ff absorption transitions.
  • the inventively preferred red line emitter A ⁇ O 3 ICr is wet-chemically produced (see DE 102006054328.9 and DE 102007001903.5).
  • these rubies are very inexpensive to produce and are suitable as a conversion phosphor for pcLEDs to produce warm white light with high efficiency and superior color rendering due to deep red emission.
  • These phosphors can be prepared in a wet-chemical process in which 0.01 to 10 wt% of Cr 3+ or Cr 2 O 3 doped Al 2 O 3 particles are obtained, which have an adjustable size and uniform morphology.
  • the educts for producing the phosphor consist of the base material (eg salt solutions of aluminum) and at least one Cr (III) -containing dopant.
  • Suitable starting materials are inorganic and / or organic substances such as nitrates, carbonates, bicarbonates, hydrogen phosphates, phosphates, carboxylates, alcoholates, acetates, oxalates, halides, sulfates, organometallic compounds, hydroxides and / or oxides of the metals, semimetals, transition metals and / or rare earths, which are dissolved and / or suspended in inorganic and / or organic liquids.
  • mixed nitrate solutions, chloride or hydroxide solutions are used which contain the corresponding elements in the required stoichiometric ratio.
  • the wet-chemical preparation generally has the advantage that the resulting materials have a higher uniformity with regard to the stoichiometric composition, the particle size and the morphology of the particles from which the red line emitter according to the invention is produced.
  • the wet-chemical preparation of the phosphor preferably takes place after precipitation and / or solination.
  • the preparation of the line emitter according to the invention is carried out by conventional methods from the corresponding metal and / or rare earth salts, preferably from an aluminum sulfate, potassium sulfate, sodium sulfate and chrome alum solution).
  • the production process is described in detail in
  • EP 763573 described.
  • phosphors or precursors thereof are applied to the ruby particles in the process conditions known to those skilled in the art.
  • the material is dried and subjected to an annealing process, which can take place up to 1700 0 C in several stages, and (partial) under reduc- ornamental conditions at temperatures.
  • the phosphor is annealed for several hours at temperatures between 600 and 1800 0 C, preferably between 800 and 1700 0 C. In this case, the phosphor precursor is converted into the actual phosphor.
  • annealing it is preferable to carry out the annealing at least partially under reducing conditions (for example with carbon monoxide, forming gas, pure or diluted hydrogen or at least a vacuum or oxygen deficiency atmosphere).
  • reducing conditions for example with carbon monoxide, forming gas, pure or diluted hydrogen or at least a vacuum or oxygen deficiency atmosphere.
  • inventive red line emitter can also be prepared by single-crystal synthesis methods (for example according to the Verneuil method, see Contacts (Merck) 1991, No. 2, 17-32 or Ullmann (4.) 15, 146, Source: CD Römpp Chemie Lexicon - Version 1.0, Stuttgart / New York: Georg Thieme Verlag 1995)
  • the dissolved or suspended educts with a surface-active agent, preferably a glycol, more
  • Line emitter phosphor is created.
  • Both the red and green emitting conversion phosphors which are the phosphor layer, are chemically stable to degradation during operation of the LED, i. they show no tendency to hydrolysis and no reaction with materials from their environment.
  • the two aqueous solutions (a) and (b) are added simultaneously to 200 ml of deionized water while stirring within 15 min. It is stirred for another 15 min. The resulting solution is evaporated to dryness and the resulting solid annealed at about 1200 0 C for 5 h. Water is added to wash out free sulphate. After customary purification steps with water and drying, the desired phosphors Ali.99iO 3 : Cr 0 .oo9 are formed.
  • Example 3 Preparation of the red phosphor NaO 5 Yo ⁇ Eu 0 1 MoO 4 3.06 g of yttrium nitrate hexahydrate and 0.892 g of europium nitrate hexahydrate are dissolved in 100 ml of ethylene glycol [solution 1]. At the same time a Solution of 1, 210 g of sodium molybdate dihydrate in 50 ml of deionized water [Solution 2]. 20 ml of solution 1 were initially charged, to which was added a mixture of 45 ml of solution 2, 45 ml of ethylene glycol and 3 ml of NaOH solution. (1M) dropped. After the dropping, the mixture was refluxed for 6 hours.
  • the mixture was transferred to a muffle furnace and calcined there at 600 0 C for 5 hours.
  • solution 1 2.120 g of lanthanum chloride hexahydrate and 1.467 g of europium chloride hexahydrate are dissolved in 100 ml of demineralized water [solution 1]. At the same time, a solution of 1.815 g of sodium molybdate dihydrate and 2.474 g of sodium tungstate dihydrate in 100 ml of deionized water is prepared [solution 2]. From solution 1, 100 ml are introduced, to this solution 2 is added dropwise (pH should be in the range of 7.5 - 8, possibly with NaOH solution (1 M) correct). Subsequently, the mixture is refluxed for 6 hours. After cooling the reaction solution, the precipitate is filtered off and dried, then calcined at 600 0 C for 5 h.
  • Example 7 Preparation of the red phosphor La 112 Eu 01S MoO 4 by complexing with citric acid 1.024 g of molybdenum (IV) oxide are dissolved in 10 ml of H 2 O 2 (30%) with gentle heating. To the yellow solution, add 4.608 g of citric acid, together with 10 ml of dist. H 2 O given. Subsequently, 1.040 g of La (NO 3 ) x 6 H 2 O and 0.714 g of Eu (NO 3 ) x 6 H 2 O and 0.340 g of NaNO 3 are added and made up to 40 ml. The yellow solution is dried in a vacuum drying cabinet, initially forming a blue foam, from which finally results in a blue powder. The solid is then calcined at 600 ° C. for 5 hours.
  • Example 8 Preparation of the red phosphor Lai, 2 Euo, 8 W0 4 by complexing with citric acid
  • ammonium bicarbonate 537.6 g of ammonium bicarbonate are dissolved in 3 liters of deionized water.
  • 205.216 g of aluminum chloride hexahydrate, 228.293 g of lutetium chloride, water-containing (x H 2 O) and 3.617 g of cerium chloride hexahydrate are dissolved in about 400 ml of deionized water and added rapidly to the bicarbonate solution. drips, while the pH value by addition of conc. Ammonia are kept at pH 8. Then it is stirred for another hour. After aging, the precipitate is filtered off and dried in a drying oven at about 12O 0 C.
  • the dried precipitate is crushed and then calcined for 4 hours at 1000 ° C in air.
  • the product is then mortared again and calcined at 1700 0 C in forming gas for 8 hours.
  • Example 12 Production of an LED and Installation in a Liquid Crystal Display
  • the phosphor from Example 10 green phosphor
  • the red phosphor from Example 6 are used in a quantitative ratio of 1: 2.17 in both components A and B of a silicone resin system OE 6336 from Dow
  • a and 5 ml of component B are mixed homogeneously and filled into a cartridge, which is connected to the dispensing valve of a dispenser.
  • COB chip on board
  • raw LEDs consisting of bonded InGaN chips each having a surface area of 1 mm 2 and emitting at 450 nm wavelength are fixed.
  • domes are applied to each chip.
  • the domes consist of the thixotropic mixture of the two silicone components and the two phosphors, as well as the silica gel powder.
  • the thus treated COB LEDs are then exposed to a temperature of 15O 0 C, in which the silicone is solidified.
  • the LEDs can now be put into operation and emit white light a color temperature of 6000 K.

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  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Mathematical Physics (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Luminescent Compositions (AREA)
  • Planar Illumination Modules (AREA)

Abstract

L'invention concerne un dispositif d'affichage à cristaux liquides pourvu d'un système de rétroéclairage comportant une source de lumière blanche qui contient une diode à semi-conducteurs et une couche de luminophores constituée d'une combinaison d'au moins deux luminophores, au moins un luminophore émettant une lumière rouge et au moins un luminophore émettant une lumière verte. L'invention concerne également son procédé de production.
EP08774036A 2007-08-20 2008-07-23 Rétroéclairage de dispositif d'affichage à cristaux liquides comportant une combinaison del-luminophores Withdrawn EP2179323A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102007039260A DE102007039260A1 (de) 2007-08-20 2007-08-20 LCD-Hintergrundbeleuchtung mit LED-Leuchtstoffen
PCT/EP2008/006007 WO2009024229A1 (fr) 2007-08-20 2008-07-23 Rétroéclairage de dispositif d'affichage à cristaux liquides comportant une combinaison del-luminophores

Publications (1)

Publication Number Publication Date
EP2179323A1 true EP2179323A1 (fr) 2010-04-28

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Application Number Title Priority Date Filing Date
EP08774036A Withdrawn EP2179323A1 (fr) 2007-08-20 2008-07-23 Rétroéclairage de dispositif d'affichage à cristaux liquides comportant une combinaison del-luminophores

Country Status (8)

Country Link
US (1) US20110299008A1 (fr)
EP (1) EP2179323A1 (fr)
JP (1) JP2010537375A (fr)
KR (1) KR20100074142A (fr)
CN (1) CN101784948A (fr)
DE (1) DE102007039260A1 (fr)
TW (1) TW200925742A (fr)
WO (1) WO2009024229A1 (fr)

Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100277673A1 (en) * 2008-01-03 2010-11-04 Koninklijke Philips Electronics N.V. Display device and illumination device
WO2011144236A1 (fr) * 2010-05-17 2011-11-24 Goodrich Lighting Systems Gmbh Éclairage intérieur d'avion
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WO2009024229A9 (fr) 2009-06-18
TW200925742A (en) 2009-06-16
KR20100074142A (ko) 2010-07-01
CN101784948A (zh) 2010-07-21
DE102007039260A1 (de) 2009-02-26

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