US20020180348A1 - Organic electroluminescent device with a defraction grading and luminescent layer - Google Patents

Organic electroluminescent device with a defraction grading and luminescent layer Download PDF

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US20020180348A1
US20020180348A1 US09/275,409 US27540999A US2002180348A1 US 20020180348 A1 US20020180348 A1 US 20020180348A1 US 27540999 A US27540999 A US 27540999A US 2002180348 A1 US2002180348 A1 US 2002180348A1
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diffraction grating
organic electroluminescent
electroluminescent device
light
organic
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Atsushi Oda
Hitoshi Ishikawa
Satoru Toguchi
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Samsung Display Co Ltd
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NEC Corp
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B32LAYERED PRODUCTS
    • B32BLAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02Physical, chemical or physicochemical properties
    • B32B7/023Optical properties
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10KORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00Organic light-emitting devices
    • H10K50/80Constructional details
    • H10K50/85Arrangements for extracting light from the devices
    • HELECTRICITY
    • H10SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10KORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00Organic light-emitting devices
    • H10K50/80Constructional details
    • H10K50/805Electrodes
    • H10K50/82Cathodes
    • H10K50/822Cathodes characterised by their shape

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  • This invention relates to organic electroluminescent devices having high luminous efficiency.
  • Organic electroluminescent devices are self-luminous devices based on the principle that, when an electric field is applied, a fluorescent material emits light owing to the energy of the recombination of positive holes injected from an anode and electrons injected from a cathode. Since low-voltage driven organic electroluminescent devices of the laminated structure type were reported by C. W. Tang et al. (e.g., C. W. Tang and S. A. VanSlyke, Applied Physics Letters, Vol. 51, p. 913, 1987), active investigations on organic electroluminescent devices using organic materials as components have been carried on. Tang et al.
  • the laminated structure are such that the efficiency of the injection of positive holes into the luminescent layer can be enhanced, the efficiency of the formation of excitons by recombination can be enhanced by blocking electrons injecting from the cathode, and the excitons formed in the luminescent layer can be confined.
  • the well-known structures of organic electroluminescent devices include, for example, a two-layer type consisting of a hole transport (or injection) layer and an electron-transporting luminescent layer, and a triple-layered type consisting of a hole transport (or injection) layer, a luminescent layer and an electron transport (or injection) layer.
  • a two-layer type consisting of a hole transport (or injection) layer and an electron-transporting luminescent layer
  • a triple-layered type consisting of a hole transport (or injection) layer, a luminescent layer and an electron transport (or injection) layer.
  • the method of improving light output efficiency has conventionally been investigated in light-emitting devices having a similar structure, such as inorganic electroluminescent devices.
  • a method for enhancing efficiency by imparting light-condensing properties to the substrate Japanese Patent Laid-Open No. 314795/'88
  • a method for enhancing efficiency by forming reflecting surfaces on the sides or other parts of the device Japanese Patent Laid-Open No. 220394/'89.
  • These methods are effective for devices having a large light emission area.
  • devices having a minute picture element area such as dot matrix displays, it is difficult to fabricate lenses for providing light-condensing properties or form lateral reflecting surfaces or the like.
  • the luminescent layer of an organic electroluminescent device has a thickness of several micrometers or less, it is difficult to make the device tapered and form reflecting mirrors on the sides thereof according to current fine machining techniques. Even if it is possible, a considerable increase in cost will be caused.
  • a method for forming an antireflection film by interposing a flat layer having an intermediate refractive index between the glass substrate and the luminescent layer is also known (Japanese Patent Laid-Open No. 172691/'87). This method is effective in improving light output efficiency in the forward direction, but cannot prevent total reflection. Consequently, this method is effective for inorganic electroluminescent devices having a high refractive index, but fails to produce a remarkable efficiency-improving effect on organic electroluminescent devices using a luminescent material having a relatively low refractive index.
  • the conventional light output method used for organic electroluminescent devices is still unsatisfactory, and the development of a new light output method is essential for the purpose of enhancing the efficiency of organic electroluminescent devices.
  • Japanese Patent Laid-open No. 83688/96 discloses an organic EL device having a light scattering part on an outside surface of the element.
  • Japanese Patent Laid-open No. 115667/97 discloses an EL device having a light reflecting structure which reflects light from the light emitting surface.
  • Japanese Utility-model Laid-open No. 54184/88 discloses an EL device having micro lense film on the EL element.
  • An object of the present invention is to improve light output efficiency in organic electroluminescent devices and thereby provide organic electroluminescent devices having higher efficiency.
  • the present invention provides a EL device which has the following feature.
  • the device additionally includes a diffraction grating or zone plate as a constituent element.
  • the present invention also has the following features.
  • the anode and the cathode form the same picture elements, one of these electrodes is an electrode reflecting visible light, and the diffraction grating or zone plate is formed in this reflecting electrode.
  • the device has a structure in which the diffraction grating or zone plate, the reflecting electrode, the organic layers and the transparent electrode are formed on a substrate in the order mentioned.
  • the anode and the cathode form the same picture elements, one of these electrodes is an electrode reflecting visible light, and the diffraction grating or zone plate is formed in the electrode opposite to the reflecting electrode.
  • the device has a structure in which the diffraction grating or zone plate, the transparent electrode, the organic layers and the reflecting electrode are formed on a transparent substrate in the order mentioned.
  • the diffraction grating or zone plate has no light-intercepting part.
  • the diffraction grating has a two-dimensional periodic configuration.
  • the present invention relates to an organic electroluminescent device having one or more organic thin-film layers including a luminescent layer between an anode and a cathode, the device additionally includes a diffraction grating or zone plate as a constituent element.
  • This diffraction grating or zone plate may be either of the reflection type or the transmission type.
  • a diffraction grating or zone plate of the transmission type not only an amplitude grating formed by providing it with light-intercepting parts can be used, but also a phase grating formed by modulating the thickness of a layer having a different refractive index may be used to further enhance light output efficiency.
  • a grating having a two-dimensional periodic configuration may be used.
  • a grating having a two-dimensional periodic configuration may be used.
  • FIG. 1 is a sectional view for explaining the structure of a device having a reflection type diffraction grating according to the present invention
  • FIG. 2 is a sectional view for explaining the structure of a device having a transmission type diffraction grating according to the present invention
  • FIG. 3 is a schematic view for explaining the reflection of light on a diffraction grating
  • FIG. 4 is a graph for explaining the relationship between incidence angle and exit angle for a diffraction grating having a grating interval of 1 mm, a wavelength of 500 nm, and a refractive index of 1.7;
  • FIG. 5 is a graph showing the dependence of incidence angle and exit angle on the grating interval/optical wavelength ratio for first-order diffraction by a diffraction grating
  • FIG. 6 is a plan view for explaining a zone plate
  • FIG. 7 is a plan view of a two-dimensional grating pattern used in Examples 4 and 5;
  • FIG. 8 is a sectional view for explaining a conventional organic electroluminescent device.
  • the refractive index of the organic layer including the luminescent layer is higher than that of the substrate material (e.g., glass), so that all of the light produced therein cannot be taken out owing to the occurrence of total reflection at the interface between the organic layer and the substrate. Even where the light is taken out from the side opposite to the substrate, total reflection also occurs at the interface between the device and air owing to the difference in refractive index between them.
  • the principle of the present invention is that, in order to suppress such total reflection, a diffraction grating is formed in the substrate interface or the reflecting surface so as to alter the incidence angle of light with respect to the light output surface and thereby enhance light output efficiency.
  • the critical angle for total reflection is 36.0 degrees.
  • the exit angle observed when light having a wavelength of 500 nm is incident on a reflection type diffraction grating having a grating interval of 2 ⁇ m is shown in FIG. 4.
  • the incidence angle in order to give an exit angle within 36 degrees, the incidence angle must be less than 46 degrees for first-order diffraction, must be less than 60 degrees for second-order diffraction, and may have any desired value for third-order diffraction.
  • the diffraction grating serves as a reflecting surface. Consequently, most of the light having an incidence angle greater than 36 degrees and having undergone total reflection at the interface between the transparent electrode 2 and the ambient medium of the device has an exit angle less than 36 degrees. Thus, this light reaches again the interface between the transparent electrode and the ambient medium of the device, and leaves the device without undergoing total reflection.
  • the component obtained by first-order diffraction and reflected at an exit angle greater than 36 degrees undergoes total reflection at the interface between the transparent electrode and the ambient medium of the device, and strikes again on the diffraction grating. After this process is repeated, almost all of the light is eventually taken out of the device.
  • the reflection type diffraction grating used in this case may have any desired shape, so long as it can function as a diffraction grating.
  • a laminary grating having a rectangular cross section or an echelette grating having a tapered cross section may be formed on the substrate, and the cathode may be deposited thereon so as to serve as a reflecting surface.
  • the cathode may be deposited in the form of alternating stripes by using two cathode materials having different reflection coefficients, or the cathode itself may be formed in a striped pattern to make a diffraction grating.
  • a device may be fabricated by forming a diffraction grating 5 on a substrate 1 and then depositing thereon an anode 2 , an organic layer 3 and a cathode 4 in that order, as shown in FIG. 2.
  • the transmission type diffraction grating may comprise either an amplitude grating or a phase grating, and may have any desired shape.
  • a phase grating may be made by forming grooves in the substrate surface, depositing thereon a layer of a transparent material having a different refractive index, planarizing it, and then depositing an anode, an organic layer and a cathode successively in the usual manner.
  • a material opaque to light may be deposited on the substrate surface in the form of stripes, or the anode itself may be formed in a striped pattern. In the latter case, the anode material may be either transparent or opaque.
  • a device may be fabricated by forming a gold electrode having a striped pattern as the anode, and then depositing thereon an organic layer and a cathode.
  • the dimensions of the diffraction grating should be determined so that the light output efficiency is enhanced for the desired wavelength region of the electroluminescent device.
  • the effect of the ratio (R) of the grating interval to the optical wavelength for the desired wavelength i.e., the value obtained by dividing the wavelength by the refractive index
  • the ratio is unduly large, the diffraction grating is less effective in reducing the exit angle, so that reflection at a mirror surface is repeated many times to cause a considerable loss.
  • the ratio is unduly small, light having a large incidence angle gives reflected light having a large exit angle, so that the proportion of light taken out in the forward direction is decreased.
  • unduly large and unduly small ratios both reduce the light output efficiency. Accordingly, it is desirable that the ratio is in the range of 0.1 to 10.
  • a diffraction grating made by forming grooves in a concentric pattern may also be used.
  • the intervals of the concentric grooves may be periodic or, as shown in FIG. 6, may be determined according to the interval rule for the formation of a zone plate.
  • these diffraction gratings may also be made by forming grooves in the substrate or by forming an electrode itself in a grating pattern.
  • the groove may have any desired cross-sectional shape.
  • the anode functions to inject positive holes into a hole transport layer, and it is effective that the anode has a work function of not less than 4.5 eV.
  • Specific examples of the anode materials which can be used in the present invention include indium-tin oxide alloy (ITO); tin oxide (NESA); metals such as gold, silver, platinum and copper, and their oxides; and mixtures thereof.
  • the cathode serves to inject electrons into an electron transport layer or a luminescent layer, and it is preferable to use a material having a small work function.
  • cathode material examples include indium, aluminum, magnesium, magnesium-indium alloy, magnesium-aluminum alloy, aluminum-lithium alloy, aluminum-scandium-lithium alloy, magnesium-silver alloy, and mixtures thereof.
  • one of the anode and the cathode is transparent in the region of visible light, and the other has high reflectivity.
  • No particular limitation is placed on the thicknesses of these electrodes, so long as they can perform their proper functions. However, their thicknesses are preferably in the range of 0.02 to 2 ⁇ m.
  • the organic electroluminescent devices of the present invention have a structure in which one or more organic layers are disposed between the aforesaid electrodes, and no additional restriction is imposed on their structure.
  • Examples thereof are those consisting of (1) an anode, a luminescent layer and a cathode, (2) an anode, a hole transport layer, a luminescent layer, an electron transport layer and a cathode, (3) an anode, a hole transport layer, a luminescent layer and a cathode, and (4) an anode, a luminescent layer, an electron transport layer and a cathode.
  • a thin-film layer formed of an inorganic dielectric or insulator e.g., lithium fluoride, magnesium fluoride, silicon oxide, silicon dioxide or silicon nitride
  • the type of the luminescent material used in the present invention there may be used any compound that is commonly used as a luminescent material.
  • examples thereof include tris(8-quinolinol)-aluminum complex (Alq3) [1], bis(diphenylvinyl)biphenyl (BDPVBi) [2], 1,3-bis(p-t-butylphenyl-1,3,4-oxadiazolyl)phenyl (OXD-7) [3], N,N′-bis(2,5-di-t-butylphenyl)perylenetetracarboxylic acid diimide (BPPC) [4] and 1,4-bis(p-tolyl-p-methylstyrylphenylamino)naphthalene [5].
  • Alq3 tris(8-quinolinol)-aluminum complex
  • BDPVBi bis(diphenylvinyl)biphenyl
  • OXD-7 1,3-bis(
  • a layer of a charge transport material doped with a fluorescent material may be used as a luminescent material.
  • a layer of a quinolinol-metal complex such as the aforesaid Alq3[1], doped with 4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) [6], a quinacridone derivative such as 2,3-quinacridone [7] or a coumarin derivative such as 3-(2′-benzothiazole)-7-diethylaminocoumarin [8]; a layer of the electron transport material bis(2-methyl-8-hydroxyquinoline)-4-phenylphenol-aluminum complex [9] doped with a fused polycyclic aromatic compound such as perylene [10]; or a layer of the hole transport material 4,4′-bis(m-tolylphenylamino)biphenyl (TPD) [11] doped with rubren
  • the type of the hole transport material used in the present invention there may be used any compound that is commonly used as a hole transport material.
  • Examples thereof include triphenyldiamines such as bis[di(p-tolyl)aminophenyl]-1,1-cyclohexane [13], TPD [11] and N,N′-diphenyl-N,N′-bis(1-naphthyl)-1,1′-biphenyl-4,4′-diamine (NPB) [14]; and starburst type molecules (e.g., [15] to [17]).
  • triphenyldiamines such as bis[di(p-tolyl)aminophenyl]-1,1-cyclohexane [13], TPD [11] and N,N′-diphenyl-N,N′-bis(1-naphthyl)-1,1′-biphenyl-4,4′-diamine (NPB) [
  • the type of the electron transport material used in the present invention there may be used any compound that is commonly used as an electron transport material.
  • examples thereof include oxadiazole derivatives such as 2-(4-biphenylyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole (Bu-PBD) [18] and OXD-7[3]; triazole derivatives (e.g., [19] and [20]); and quinolinol-metal complexes (e.g., [1], [9], and [21] to [24]).
  • oxadiazole derivatives such as 2-(4-biphenylyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole (Bu-PBD) [18] and OXD-7[3]
  • triazole derivatives e.g., [19] and [20]
  • quinolinol-metal complexes e.g., [1],
  • the organic thin-film layers each containing a compound as described above, which is used in the organic electroluminescent device of the present invention can be formed according to any well-known method such as vapor evaporation, molecular beam evaporation (MBE), or coating method such as dipping (in a solution prepared by dissolving the compound in a solvent), spin coating, casting, bar coating or roll coating.
  • MBE molecular beam evaporation
  • coating method such as dipping (in a solution prepared by dissolving the compound in a solvent), spin coating, casting, bar coating or roll coating.
  • each organic layer used in the organic electroluminescent device of the present invention No particular limitation is placed on the thickness of each organic layer used in the organic electroluminescent device of the present invention. However, it is usually preferable that each organic layer have a thickness ranging from several tens of nanometers to 1 micrometer.
  • this device comprises a substrate 1 having thereon an anode 2 , an organic layer 3 (composed of a hole injection layer, a luminescent layer and an electron transport layer) and a cathode 4 .
  • An ITO layer having a thickness of 100 nm was deposited on a 50 mm ⁇ 25 mm glass substrate (a thickness of 1.1 mm; NA 45 manufactured by Hoya Corp.) by sputtering.
  • a metal mask was used to deposit the ITO layer in the form of stripes measuring 2 mm ⁇ 50 mm. Its sheet resistance was 20 ⁇ / ⁇ .
  • an organic luminescent layer was deposited by means of a resistance heating type vapor evaporator. While the substrate was mounted in the upper part of a vacuum chamber, a molybdenum boat was placed at a position 250 mm below the substrate. The substrate was arranged so as to give an incidence angle of 38° and rotated at a speed of 30 rotation per minutes. As soon as a pressure of 5 ⁇ 10 ⁇ 7 Torr was reached, evaporation was started, and the deposition rate was controlled by means of a crystal oscillator type film thickness controller mounted beside the substrate. The deposition rate was preset at 0.15 nm per second.
  • a hole injection layer comprising compound [15] was deposited to a thickness of 40 nm. Thereafter, a 70 nm thick luminescent layer comprising compound [5] and a 40 nm thick electron transport layer comprising compound [19] were successively evaporated under the same conditions as described above.
  • a cathode comprising a magnesium-silver alloy was deposited by evaporating magnesium and silver simultaneously from separate boats.
  • the deposition rates of magnesium and silver were adjusted to 1.0 and 0.2 nm per second, respectively, and the film thickness was preset at 200 nm.
  • a metal mask was used to deposit the cathode in such a way that it consisted of 12 stripes measuring 25 mm ⁇ 2 mm which were arranged at intervals of 1 mm and in a direction orthogonal to the stripes of ITO.
  • this device When a voltage of 10 V was applied, this device exhibited a current density of 50 mA/cm 2 and a luminance of 1,950 cd/m 2 . Consequently, its efficiency was 3.9 cd/A or 1.22 lm/W.
  • a grating pattern having a line width of 1 ⁇ m and an interval of 1 ⁇ m was formed according to a photolithographic process. Specifically, a 2 ⁇ m thick layer of an i-line resist (THMR-iP1700; manufactured by Tokyo Ohka Kogyo Co., Ltd.) was formed on the substrate by spin coating, and patterned by means of an i-line stepper. Then, this substrate was soaked in a hydrofluoric acid solution to form grooves having a depth of 200 nm, and the remaining resist was removed by use of an exclusive stripping fluid. After a cathode comprising a 200 nm thick layer of a magnesium-silver alloy was evaporated thereon under the same conditions as described in Comparative Example 1, organic layers with reverse order of Comparative Example 1 and an ITO layer were successively deposited.
  • THMR-iP1700 manufactured by Tokyo Ohka Kogyo Co., Ltd.
  • a device was fabricated in exactly the same manner as in Example 1, except that the grating pattern had a line width of 0.40 ⁇ m and an interval of 0.40 ⁇ m.
  • a device was fabricated in exactly the same manner as in Example 1, except that the two-dimensional grating pattern shown in FIG. 7 was used. When a voltage of 10 V was applied, this device exhibited a current density of 52 mA/cm 2 and a luminance of 3,733 cd/m 2 . Consequently, its efficiency was 7.17 cd/A or 2.25 lm/W.
  • a device was fabricated in exactly the same manner as in Example 3, except that the two-dimensional grating pattern shown in FIG. 7 was used. When a voltage of 10 V was applied, this device exhibited a current density of 58 mA/cm 2 and a luminance of 3,210 cd/m 2 . Consequently, its efficiency was 5.53 cd/A or 1.73 lm/W.
  • n is an integer ranging from 1 to 100. Grooves were formed in the zones where n changes from an even number to an odd number. After this zone pattern was formed so as to cover a 5 mm ⁇ 5 mm area of the substrate surface, the treatment (e.g., planarization) and the formation of several layers were carried out in the same manner as in Example 3.

Abstract

This invention provides organic electroluminescent devices in which a diffraction grating is formed as a constituent element thereof on the reflecting surface of the cathode or on the light output side, resulting in an improvement in light output efficiency.

Description

    BACKGROUND OF THE INVENTION
  • 1. Field of the Invention [0001]
  • This invention relates to organic electroluminescent devices having high luminous efficiency. [0002]
  • 2. Description of the Prior Art [0003]
  • Organic electroluminescent devices are self-luminous devices based on the principle that, when an electric field is applied, a fluorescent material emits light owing to the energy of the recombination of positive holes injected from an anode and electrons injected from a cathode. Since low-voltage driven organic electroluminescent devices of the laminated structure type were reported by C. W. Tang et al. (e.g., C. W. Tang and S. A. VanSlyke, Applied Physics Letters, Vol. 51, p. 913, 1987), active investigations on organic electroluminescent devices using organic materials as components have been carried on. Tang et al. used tris(8-quinolinol)-aluminum for the luminescent layer and a triphenyldiamine derivative for the hole transport layer. Advantages of the laminated structure are such that the efficiency of the injection of positive holes into the luminescent layer can be enhanced, the efficiency of the formation of excitons by recombination can be enhanced by blocking electrons injecting from the cathode, and the excitons formed in the luminescent layer can be confined. As can be seen from these examples, the well-known structures of organic electroluminescent devices include, for example, a two-layer type consisting of a hole transport (or injection) layer and an electron-transporting luminescent layer, and a triple-layered type consisting of a hole transport (or injection) layer, a luminescent layer and an electron transport (or injection) layer. In these devices of the laminated structure type, various attempts have been made to modify the device structure or their fabrication method and thereby enhance the efficiency of the recombination of injected positive holes and electrons. [0004]
  • However, in organic electroluminescent devices, the probability of singlet formation during carrier recombination is limited owing to its dependence on spin statistics. Consequently, there is an upper limit to the probability of light emission. This upper limit is known to have a value of about 25%. Moreover, in organic electroluminescent devices, light having an exit angle greater than the critical angle undergoes total reflection owing to the influence of the refractive index of the luminescent material, and cannot be taken out of the device as shown in FIG. 1. Consequently, on the assumption that the luminescent material has a refractive index of 1.6, only 20% of the total light produced can be effectively utilized. When the probability of singlet formation is also taken into consideration, energy conversion efficiency is inevitably limited to as low as about 5% (Tetsuo Tsutsui, “Present State and Trend of Organic Electroluminescent”, The Display Monthly, Vol. 1, No. 3, p. 11, September, 1995). In organic electroluminescent devices in which the probability of light emission is severely limited, low light output efficiency would cause a fatal reduction in efficiency. [0005]
  • The method of improving light output efficiency has conventionally been investigated in light-emitting devices having a similar structure, such as inorganic electroluminescent devices. For example, there have been proposed a method for enhancing efficiency by imparting light-condensing properties to the substrate (Japanese Patent Laid-Open No. 314795/'88) and a method for enhancing efficiency by forming reflecting surfaces on the sides or other parts of the device (Japanese Patent Laid-Open No. 220394/'89). These methods are effective for devices having a large light emission area. However, for devices having a minute picture element area, such as dot matrix displays, it is difficult to fabricate lenses for providing light-condensing properties or form lateral reflecting surfaces or the like. Moreover, since the luminescent layer of an organic electroluminescent device has a thickness of several micrometers or less, it is difficult to make the device tapered and form reflecting mirrors on the sides thereof according to current fine machining techniques. Even if it is possible, a considerable increase in cost will be caused. Furthermore, a method for forming an antireflection film by interposing a flat layer having an intermediate refractive index between the glass substrate and the luminescent layer is also known (Japanese Patent Laid-Open No. 172691/'87). This method is effective in improving light output efficiency in the forward direction, but cannot prevent total reflection. Consequently, this method is effective for inorganic electroluminescent devices having a high refractive index, but fails to produce a remarkable efficiency-improving effect on organic electroluminescent devices using a luminescent material having a relatively low refractive index. [0006]
  • Accordingly, the conventional light output method used for organic electroluminescent devices is still unsatisfactory, and the development of a new light output method is essential for the purpose of enhancing the efficiency of organic electroluminescent devices. [0007]
  • Japanese Patent Laid-open No. 83688/96 discloses an organic EL device having a light scattering part on an outside surface of the element. Japanese Patent Laid-open No. 115667/97 discloses an EL device having a light reflecting structure which reflects light from the light emitting surface. Japanese Utility-model Laid-open No. 54184/88 discloses an EL device having micro lense film on the EL element. [0008]
  • These three publications neither teach nor suggest the present organic EL device having a diffraction grating or zone plate as a constituent element. [0009]
  • SUMMARY OF THE INVENTION
  • An object of the present invention is to improve light output efficiency in organic electroluminescent devices and thereby provide organic electroluminescent devices having higher efficiency. [0010]
  • In order to accomplish the above objects, the present invention provides a EL device which has the following feature. [0011]
  • (1) In an organic electroluminescent device having one or more organic layers including a luminescent layer between an anode and a cathode, the device additionally includes a diffraction grating or zone plate as a constituent element. [0012]
  • In preferred embodiments, the present invention also has the following features. [0013]
  • (2) In the device described above in (1), the anode and the cathode form the same picture elements, one of these electrodes is an electrode reflecting visible light, and the diffraction grating or zone plate is formed in this reflecting electrode. [0014]
  • (3) In the device described above in (2), the device has a structure in which the diffraction grating or zone plate, the reflecting electrode, the organic layers and the transparent electrode are formed on a substrate in the order mentioned. [0015]
  • (4) In the device described above in (1), the anode and the cathode form the same picture elements, one of these electrodes is an electrode reflecting visible light, and the diffraction grating or zone plate is formed in the electrode opposite to the reflecting electrode. [0016]
  • (5) In the device described above in (4), the device has a structure in which the diffraction grating or zone plate, the transparent electrode, the organic layers and the reflecting electrode are formed on a transparent substrate in the order mentioned. [0017]
  • (6) In the device described above in (4) or (5), the diffraction grating or zone plate has no light-intercepting part. [0018]
  • (7) In the device described above in any of (1) to (6), the diffraction grating has a two-dimensional periodic configuration. [0019]
  • As described above, the present invention relates to an organic electroluminescent device having one or more organic thin-film layers including a luminescent layer between an anode and a cathode, the device additionally includes a diffraction grating or zone plate as a constituent element. This diffraction grating or zone plate may be either of the reflection type or the transmission type. In the case of a diffraction grating or zone plate of the transmission type, not only an amplitude grating formed by providing it with light-intercepting parts can be used, but also a phase grating formed by modulating the thickness of a layer having a different refractive index may be used to further enhance light output efficiency. Moreover, in the case of a diffraction grating, a grating having a two-dimensional periodic configuration may be used. Thus, as compared with a conventional diffraction grating consisting of a plurality of stripes, light output in a direction parallel to the stripes can be improved. [0020]
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1 is a sectional view for explaining the structure of a device having a reflection type diffraction grating according to the present invention; [0021]
  • FIG. 2 is a sectional view for explaining the structure of a device having a transmission type diffraction grating according to the present invention; [0022]
  • FIG. 3 is a schematic view for explaining the reflection of light on a diffraction grating; [0023]
  • FIG. 4 is a graph for explaining the relationship between incidence angle and exit angle for a diffraction grating having a grating interval of 1 mm, a wavelength of 500 nm, and a refractive index of 1.7; [0024]
  • FIG. 5 is a graph showing the dependence of incidence angle and exit angle on the grating interval/optical wavelength ratio for first-order diffraction by a diffraction grating; [0025]
  • FIG. 6 is a plan view for explaining a zone plate; [0026]
  • FIG. 7 is a plan view of a two-dimensional grating pattern used in Examples 4 and 5; and [0027]
  • FIG. 8 is a sectional view for explaining a conventional organic electroluminescent device.[0028]
  • DETAILED DESCRIPTION OF THE INVENTION
  • First of all, the principle of the present invention is explained below. [0029]
  • In an organic electroluminescent device, the refractive index of the organic layer including the luminescent layer is higher than that of the substrate material (e.g., glass), so that all of the light produced therein cannot be taken out owing to the occurrence of total reflection at the interface between the organic layer and the substrate. Even where the light is taken out from the side opposite to the substrate, total reflection also occurs at the interface between the device and air owing to the difference in refractive index between them. The principle of the present invention is that, in order to suppress such total reflection, a diffraction grating is formed in the substrate interface or the reflecting surface so as to alter the incidence angle of light with respect to the light output surface and thereby enhance light output efficiency. [0030]
  • It is known that, when light strikes on a diffraction grating at an incidence angle α as shown in FIG. 3, the relationship among exit angle β, grating interval d, light wavelength λ, refractive index n, and order of diffraction k. is expressed by the following equation (A). [0031] d ( sin α - sin β ) = k λ n ( A )
    Figure US20020180348A1-20021205-M00001
  • Accordingly, for light having an incidence angle greater than the critical angle for total reflection, its incidence angle can be reduced to a value smaller than the critical angle by controlling the grating interval properly. For example, on the assumption that an organic material having a refractive index of 1.7 is used, the critical angle for total reflection is 36.0 degrees. The exit angle observed when light having a wavelength of 500 nm is incident on a reflection type diffraction grating having a grating interval of 2 μm is shown in FIG. 4. It can be seen from this figure that, in order to give an exit angle within 36 degrees, the incidence angle must be less than 46 degrees for first-order diffraction, must be less than 60 degrees for second-order diffraction, and may have any desired value for third-order diffraction. [0032]
  • In the case of a device structure as shown in FIG. 1, i.e., a structure obtained by forming a reflection [0033] type diffraction grating 5 on a surface of a substrate 1 so as to serve as a cathode 4, too, and depositing thereon an organic layer 3 and an anode 2 comprising a transparent electrode, the diffraction grating serves as a reflecting surface. Consequently, most of the light having an incidence angle greater than 36 degrees and having undergone total reflection at the interface between the transparent electrode 2 and the ambient medium of the device has an exit angle less than 36 degrees. Thus, this light reaches again the interface between the transparent electrode and the ambient medium of the device, and leaves the device without undergoing total reflection. The component obtained by first-order diffraction and reflected at an exit angle greater than 36 degrees undergoes total reflection at the interface between the transparent electrode and the ambient medium of the device, and strikes again on the diffraction grating. After this process is repeated, almost all of the light is eventually taken out of the device.
  • The reflection type diffraction grating used in this case may have any desired shape, so long as it can function as a diffraction grating. For example, a laminary grating having a rectangular cross section or an echelette grating having a tapered cross section may be formed on the substrate, and the cathode may be deposited thereon so as to serve as a reflecting surface. Alternatively, the cathode may be deposited in the form of alternating stripes by using two cathode materials having different reflection coefficients, or the cathode itself may be formed in a striped pattern to make a diffraction grating. [0034]
  • Where it is desired to use a transmission type diffraction grating, a device may be fabricated by forming a [0035] diffraction grating 5 on a substrate 1 and then depositing thereon an anode 2, an organic layer 3 and a cathode 4 in that order, as shown in FIG. 2. In this case, the transmission type diffraction grating may comprise either an amplitude grating or a phase grating, and may have any desired shape. For example, a phase grating may be made by forming grooves in the substrate surface, depositing thereon a layer of a transparent material having a different refractive index, planarizing it, and then depositing an anode, an organic layer and a cathode successively in the usual manner. In the case of an amplitude grating, a material opaque to light may be deposited on the substrate surface in the form of stripes, or the anode itself may be formed in a striped pattern. In the latter case, the anode material may be either transparent or opaque. For example, a device may be fabricated by forming a gold electrode having a striped pattern as the anode, and then depositing thereon an organic layer and a cathode.
  • When a transmission type diffraction grating is used, the light incident on the diffraction grating is divided into transmitted light and reflected light. However, since the reflected light has a smaller exit angle, it strikes on the diffraction grating again at a smaller incidence angle after being reflected by the cathode. Thus, similarly to a device using a reflection type diffraction grating, almost all of the light can be taken out of the device. [0036]
  • The dimensions of the diffraction grating should be determined so that the light output efficiency is enhanced for the desired wavelength region of the electroluminescent device. Specifically, when the wavelength of the electroluminescent device is in the region of visible light (i.e., in the wavelength region of 350 to 800 nm), the effect of the ratio (R) of the grating interval to the optical wavelength for the desired wavelength (i.e., the value obtained by dividing the wavelength by the refractive index) is shown in FIG. 5. Specifically, if the ratio is unduly large, the diffraction grating is less effective in reducing the exit angle, so that reflection at a mirror surface is repeated many times to cause a considerable loss. If the ratio is unduly small, light having a large incidence angle gives reflected light having a large exit angle, so that the proportion of light taken out in the forward direction is decreased. Thus, unduly large and unduly small ratios both reduce the light output efficiency. Accordingly, it is desirable that the ratio is in the range of 0.1 to 10. [0037]
  • In the case of an ordinary diffraction grating, no diffraction effect is produced in a direction parallel to the stripes, so that the light output efficiency in this direction cannot be enhanced. This disadvantage can be overcome by using a two-dimensional diffraction grating. Alternatively, a diffraction grating made by forming grooves in a concentric pattern may also be used. In this case, the intervals of the concentric grooves may be periodic or, as shown in FIG. 6, may be determined according to the interval rule for the formation of a zone plate. Similarly to the above-described diffraction gratings, these diffraction gratings may also be made by forming grooves in the substrate or by forming an electrode itself in a grating pattern. Moreover, the groove may have any desired cross-sectional shape. [0038]
  • Next, the various constituent elements of the device are explained below. With respect to the electrodes of an organic electroluminescent device, the anode functions to inject positive holes into a hole transport layer, and it is effective that the anode has a work function of not less than 4.5 eV. Specific examples of the anode materials which can be used in the present invention include indium-tin oxide alloy (ITO); tin oxide (NESA); metals such as gold, silver, platinum and copper, and their oxides; and mixtures thereof. On the other hand, the cathode serves to inject electrons into an electron transport layer or a luminescent layer, and it is preferable to use a material having a small work function. Although no particular limitation is placed on the type of the cathode material, specific example of usable cathode materials include indium, aluminum, magnesium, magnesium-indium alloy, magnesium-aluminum alloy, aluminum-lithium alloy, aluminum-scandium-lithium alloy, magnesium-silver alloy, and mixtures thereof. [0039]
  • With respect to these electrodes, one of the anode and the cathode is transparent in the region of visible light, and the other has high reflectivity. No particular limitation is placed on the thicknesses of these electrodes, so long as they can perform their proper functions. However, their thicknesses are preferably in the range of 0.02 to 2 μm. [0040]
  • The organic electroluminescent devices of the present invention have a structure in which one or more organic layers are disposed between the aforesaid electrodes, and no additional restriction is imposed on their structure. Examples thereof are those consisting of (1) an anode, a luminescent layer and a cathode, (2) an anode, a hole transport layer, a luminescent layer, an electron transport layer and a cathode, (3) an anode, a hole transport layer, a luminescent layer and a cathode, and (4) an anode, a luminescent layer, an electron transport layer and a cathode. Moreover, in order to improve charge injection characteristics, suppress dielectric breakdown, or enhance luminous efficiency, a thin-film layer formed of an inorganic dielectric or insulator (e.g., lithium fluoride, magnesium fluoride, silicon oxide, silicon dioxide or silicon nitride), a layer formed of a mixture of an organic material and an electrode material or metal, or a thin film of an organic polymer (e.g., polyaniline, a polyacetylene derivative, a polydiacetylene derivative, a polyvinyl carbazole derivative or a poly(p-phenylene-vinylene) derivative) may be interposed between adjacent organic layers and/or between an organic layer and an electrode. [0041]
  • No particular limitation is placed on the type of the luminescent material used in the present invention, and there may be used any compound that is commonly used as a luminescent material. As given below, examples thereof include tris(8-quinolinol)-aluminum complex (Alq3) [1], bis(diphenylvinyl)biphenyl (BDPVBi) [2], 1,3-bis(p-t-butylphenyl-1,3,4-oxadiazolyl)phenyl (OXD-7) [3], N,N′-bis(2,5-di-t-butylphenyl)perylenetetracarboxylic acid diimide (BPPC) [4] and 1,4-bis(p-tolyl-p-methylstyrylphenylamino)naphthalene [5]. [0042]
    Figure US20020180348A1-20021205-C00001
  • Alternatively, a layer of a charge transport material doped with a fluorescent material may be used as a luminescent material. Examples thereof include a layer of a quinolinol-metal complex such as the aforesaid Alq3[1], doped with 4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) [6], a quinacridone derivative such as 2,3-quinacridone [7] or a coumarin derivative such as 3-(2′-benzothiazole)-7-diethylaminocoumarin [8]; a layer of the electron transport material bis(2-methyl-8-hydroxyquinoline)-4-phenylphenol-aluminum complex [9] doped with a fused polycyclic aromatic compound such as perylene [10]; or a layer of the [0043] hole transport material 4,4′-bis(m-tolylphenylamino)biphenyl (TPD) [11] doped with rubrene [12].
    Figure US20020180348A1-20021205-C00002
  • No particular limitation is placed on the type of the hole transport material used in the present invention, and there may be used any compound that is commonly used as a hole transport material. Examples thereof include triphenyldiamines such as bis[di(p-tolyl)aminophenyl]-1,1-cyclohexane [13], TPD [11] and N,N′-diphenyl-N,N′-bis(1-naphthyl)-1,1′-biphenyl-4,4′-diamine (NPB) [14]; and starburst type molecules (e.g., [15] to [17]). [0044]
    Figure US20020180348A1-20021205-C00003
  • No particular limitation is placed on the type of the electron transport material used in the present invention, and there may be used any compound that is commonly used as an electron transport material. Examples thereof include oxadiazole derivatives such as 2-(4-biphenylyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole (Bu-PBD) [18] and OXD-7[3]; triazole derivatives (e.g., [19] and [20]); and quinolinol-metal complexes (e.g., [1], [9], and [21] to [24]). [0045]
    Figure US20020180348A1-20021205-C00004
  • No particular limitation is placed on the method for forming the various layers constituting the organic electroluminescent device of the present invention. Any conventionally known methods such as vacuum evaporation and spin coating may be employed. The organic thin-film layers each containing a compound as described above, which is used in the organic electroluminescent device of the present invention, can be formed according to any well-known method such as vapor evaporation, molecular beam evaporation (MBE), or coating method such as dipping (in a solution prepared by dissolving the compound in a solvent), spin coating, casting, bar coating or roll coating. [0046]
  • No particular limitation is placed on the thickness of each organic layer used in the organic electroluminescent device of the present invention. However, it is usually preferable that each organic layer have a thickness ranging from several tens of nanometers to 1 micrometer. [0047]
  • EXAMPLES
  • The present invention is further illustrated by the following examples. However, these examples are not to be construed to limit the scope of the invention. [0048]
  • Comparative Example 1
  • The procedure for the fabrication of an organic thin-film electroluminescent device serving as a comparative example is described below. As illustrated in FIG. 8, this device comprises a [0049] substrate 1 having thereon an anode 2, an organic layer 3 (composed of a hole injection layer, a luminescent layer and an electron transport layer) and a cathode 4. An ITO layer having a thickness of 100 nm was deposited on a 50 mm×25 mm glass substrate (a thickness of 1.1 mm; NA 45 manufactured by Hoya Corp.) by sputtering. In this step, a metal mask was used to deposit the ITO layer in the form of stripes measuring 2 mm×50 mm. Its sheet resistance was 20 Ω/□.
  • Then, an organic luminescent layer was deposited by means of a resistance heating type vapor evaporator. While the substrate was mounted in the upper part of a vacuum chamber, a molybdenum boat was placed at a position 250 mm below the substrate. The substrate was arranged so as to give an incidence angle of 38° and rotated at a speed of 30 rotation per minutes. As soon as a pressure of 5×10[0050] −7 Torr was reached, evaporation was started, and the deposition rate was controlled by means of a crystal oscillator type film thickness controller mounted beside the substrate. The deposition rate was preset at 0.15 nm per second. Under the above-described conditions, a hole injection layer comprising compound [15] was deposited to a thickness of 40 nm. Thereafter, a 70 nm thick luminescent layer comprising compound [5] and a 40 nm thick electron transport layer comprising compound [19] were successively evaporated under the same conditions as described above.
  • Subsequently, a cathode comprising a magnesium-silver alloy was deposited by evaporating magnesium and silver simultaneously from separate boats. Using the aforesaid film thickness controller, the deposition rates of magnesium and silver were adjusted to 1.0 and 0.2 nm per second, respectively, and the film thickness was preset at 200 nm. During this evaporation, a metal mask was used to deposit the cathode in such a way that it consisted of 12 stripes measuring 25 mm×2 mm which were arranged at intervals of 1 mm and in a direction orthogonal to the stripes of ITO. When a voltage of 10 V was applied, this device exhibited a current density of 50 mA/cm[0051] 2 and a luminance of 1,950 cd/m2. Consequently, its efficiency was 3.9 cd/A or 1.22 lm/W.
  • Example 1
  • On a glass substrate similar to that used in Comparative Example 1, a grating pattern having a line width of 1 μm and an interval of 1 μm was formed according to a photolithographic process. Specifically, a 2 μm thick layer of an i-line resist (THMR-iP1700; manufactured by Tokyo Ohka Kogyo Co., Ltd.) was formed on the substrate by spin coating, and patterned by means of an i-line stepper. Then, this substrate was soaked in a hydrofluoric acid solution to form grooves having a depth of 200 nm, and the remaining resist was removed by use of an exclusive stripping fluid. After a cathode comprising a 200 nm thick layer of a magnesium-silver alloy was evaporated thereon under the same conditions as described in Comparative Example 1, organic layers with reverse order of Comparative Example 1 and an ITO layer were successively deposited. [0052]
  • When a voltage of 10 V was applied, this device exhibited a current density of 55 mA/cm[0053] 2 and a luminance of 3,265 cd/m2. Consequently, its efficiency was 5.94 cd/A or 1.86 lm/W.
  • Example 2
  • A device was fabricated in exactly the same manner as in Example 1, except that the grating pattern had a line width of 0.40 μm and an interval of 0.40 μm. [0054]
  • When a voltage of 10 V was applied, this device exhibited a current density of 58 mA/cm[0055] 2 and a luminance of 4,028 cd/m2. Consequently, its efficiency was 6.94 cd/A or 2.18 lm/W.
  • Example 3
  • In order to make a diffraction grating, grooves were formed in a substrate according to the same procedure as described in Example 1. Thereafter, a 500 nm thick layer having a high refractive index was deposited over the grooves according to a sputtering process using titanium oxide as the target, and its surface was planarized by ordinary optical polishing. Subsequently, an ITO layer, an organic layer and a cathode were deposited thereon in exactly the same manner as in Comparative Example 1 to fabricate a device. [0056]
  • When a voltage of 10 V was applied, this device exhibited a current density of 50 mA/cm[0057] 2 and a luminance of 2,623 cd/m2. Consequently, its efficiency was 5.246 cd/A or 1.647 lm/W.
  • Example 4
  • A device was fabricated in exactly the same manner as in Example 1, except that the two-dimensional grating pattern shown in FIG. 7 was used. When a voltage of 10 V was applied, this device exhibited a current density of 52 mA/cm[0058] 2 and a luminance of 3,733 cd/m2. Consequently, its efficiency was 7.17 cd/A or 2.25 lm/W.
  • Example 5
  • A device was fabricated in exactly the same manner as in Example 3, except that the two-dimensional grating pattern shown in FIG. 7 was used. When a voltage of 10 V was applied, this device exhibited a current density of 58 mA/cm[0059] 2 and a luminance of 3,210 cd/m2. Consequently, its efficiency was 5.53 cd/A or 1.73 lm/W.
  • Example 6
  • The two-dimensional grating pattern shown in FIG. 6 was used. According to Fresnel's method for the formation of annular zones, the widths and intervals of zones were determined on the basis of the radius r from the center as expressed by the following equation (B). [0060] r = r 0 sin [ cos - 1 ( n1 n0 ) ] ( B )
    Figure US20020180348A1-20021205-M00002
  • In this equation, 1 is 0.08 μm, r[0061] 0 is 3 μm, and n is an integer ranging from 1 to 100. Grooves were formed in the zones where n changes from an even number to an odd number. After this zone pattern was formed so as to cover a 5 mm×5 mm area of the substrate surface, the treatment (e.g., planarization) and the formation of several layers were carried out in the same manner as in Example 3.
  • When a voltage of 10 V was applied, this device exhibited a current density of 50 mA/cm[0062] 2 and a luminance of 3,640 cd/m2. Consequently, its efficiency was 7.28 cd/A or 2.28 lm/W.

Claims (14)

What is claimed is:
1. An organic electroluminescent device having one or more organic layers including a luminescent layer between an anode and a cathode, wherein said device additionally includes a diffraction grating or zone plate as a constituent element.
2. An organic electroluminescent device as claimed in claim 1 wherein the anode and the cathode form the same picture elements, one of these electrodes is an electrode reflecting visible light, and the diffraction grating or zone plate is formed in this reflecting electrode.
3. An organic electroluminescent device as claimed in claim 2 wherein said device has a structure in which the diffraction grating or zone plate, the reflecting electrode, the organic layers and the transparent electrode are formed on a substrate in the order mentioned.
4. An organic electroluminescent device as claimed in claim 1 wherein the anode and the cathode form the same picture elements, one of these electrodes is an electrode reflecting visible light, and the diffraction grating or zone plate is formed in the electrode opposite to the reflecting electrode.
5. An organic electroluminescent device as claimed in claim 4 wherein said device has a structure in which the diffraction grating or zone plate, the transparent electrode, the organic layers and the reflecting electrode are formed on a transparent substrate in the order mentioned.
6. An organic electroluminescent device as claimed in claim 4 wherein the diffraction grating or zone plate has no light-intercepting part.
7. An organic electroluminescent device as claimed in claim 5 wherein the diffraction grating or zone plate has no light-intercepting part.
8. An organic electroluminescent device as claimed in claim 1 wherein the diffraction grating has a two-dimensional periodic configuration.
9. An organic electroluminescent device as claimed in claim 2 wherein the diffraction grating has a two-dimensional periodic configuration.
10. An organic electroluminescent device as claimed in claim 3 wherein the diffraction grating has a two-dimensional periodic configuration.
11. An organic electroluminescent device as claimed in claim 4 wherein the diffraction grating has a two-dimensional periodic configuration.
12. An organic electroluminescent device as claimed in claim 5 wherein the diffraction grating has a two-dimensional periodic configuration.
13. An organic electroluminescent device as claimed in claim 6 wherein the diffraction grating has a two-dimensional periodic configuration.
14. An organic electroluminescent device as claimed in claim 7 wherein the diffraction grating has a two-dimensional periodic configuration.
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Publication number Priority date Publication date Assignee Title
US20040056592A1 (en) * 2002-09-25 2004-03-25 Fuji Photo Film Co., Ltd. Light-emitting element
US20050077820A1 (en) * 2003-05-22 2005-04-14 Yasuharu Onishi Electroluminescent display device
US20060006778A1 (en) * 2004-06-26 2006-01-12 Joon-Gu Lee Organic electroluminescent display device and method for manufacturing the same
US20060049749A1 (en) * 2004-09-06 2006-03-09 Fuji Photo Film Co., Ltd. Organic electroluminescent device
US20060066230A1 (en) * 2004-09-28 2006-03-30 Hirofumi Kubota Organic EL display
US20060286889A1 (en) * 1999-12-15 2006-12-21 Semiconductor Energy Laboratory Co., Ltd. EL display device
US20090160317A1 (en) * 2007-12-21 2009-06-25 Herschel Clement Burstyn Increasing the external efficiency of organic light emitting diodes utilizing a diffraction grating
US20100118522A1 (en) * 2007-05-02 2010-05-13 Koninklijke Philips Electronics N.V. Light emitting device using oled panels in folded or deployed configuration
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US8232572B2 (en) 2007-11-14 2012-07-31 Canon Kabushiki Kaisha Light emitting device
US20120228647A1 (en) * 2009-08-25 2012-09-13 Sumitomo Chemical Company, Limited Organic electroluminescent element
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US6717359B2 (en) 2001-01-29 2004-04-06 Semiconductor Energy Laboratory Co., Ltd. Light emitting device and manufacturing method thereof
JP2008186815A (en) * 2001-03-23 2008-08-14 Mitsubishi Chemicals Corp Thin-film type light emitter and its manufacturing method
JP4361226B2 (en) * 2001-04-16 2009-11-11 セイコーエプソン株式会社 Light emitting element
TWI257828B (en) 2001-05-31 2006-07-01 Seiko Epson Corp EL device, EL display, EL illumination apparatus, liquid crystal apparatus using the EL illumination apparatus and electronic apparatus
US6664730B2 (en) * 2001-07-09 2003-12-16 Universal Display Corporation Electrode structure of el device
KR100437886B1 (en) * 2001-09-25 2004-06-30 한국과학기술원 High extraction efficiency photonic crystal organic light emitting device
JP2003115377A (en) 2001-10-03 2003-04-18 Nec Corp Light emitting element, its manufacturing method, and display equipment using this
US6903379B2 (en) 2001-11-16 2005-06-07 Gelcore Llc GaN based LED lighting extraction efficiency using digital diffractive phase grating
US6833667B2 (en) 2002-02-27 2004-12-21 Matsushita Electric Industrial Co., Ltd. Organic electroluminescence element and image forming apparatus or portable terminal unit using thereof
KR100581850B1 (en) 2002-02-27 2006-05-22 삼성에스디아이 주식회사 Organic electro luminescence display device and method of manufacturing the same
US6888613B2 (en) * 2002-03-01 2005-05-03 Hewlett-Packard Development Company, L.P. Diffractive focusing using multiple selectively light opaque elements
JP2003308968A (en) * 2002-04-12 2003-10-31 Rohm Co Ltd Electroluminescent element and method of manufacturing the same
US7329611B2 (en) 2002-04-11 2008-02-12 Nec Corporation Method for forming finely-structured parts, finely-structured parts formed thereby, and product using such finely-structured part
EP1504633A1 (en) * 2002-05-08 2005-02-09 Zeolux Corporation Feedback enhanced ligth emitting device
US6946677B2 (en) * 2002-06-14 2005-09-20 Nokia Corporation Pre-patterned substrate for organic thin film transistor structures and circuits and related method for making same
US6670772B1 (en) * 2002-06-27 2003-12-30 Eastman Kodak Company Organic light emitting diode display with surface plasmon outcoupling
US7038373B2 (en) * 2002-07-16 2006-05-02 Eastman Kodak Company Organic light emitting diode display
KR100865622B1 (en) * 2002-08-26 2008-10-27 삼성전자주식회사 Method for Fabrication of Photonic Crystal Structure to Improve Brightness of A Display
KR20040025383A (en) 2002-09-19 2004-03-24 삼성에스디아이 주식회사 Organic electro luminescence display device and manufacturing of the same
US6965197B2 (en) * 2002-10-01 2005-11-15 Eastman Kodak Company Organic light-emitting device having enhanced light extraction efficiency
US6831407B2 (en) * 2002-10-15 2004-12-14 Eastman Kodak Company Oled device having improved light output
JP4350996B2 (en) 2002-11-26 2009-10-28 日東電工株式会社 Organic electroluminescence device, surface light source and display device
NL1022269C2 (en) * 2002-12-24 2004-06-25 Otb Group Bv Method for manufacturing an organic electroluminescent display device, substrate for use in such a method, as well as an organic electroluminescent display device obtained with the method.
KR100908234B1 (en) * 2003-02-13 2009-07-20 삼성모바일디스플레이주식회사 EL display device and manufacturing method thereof
JP2004273122A (en) * 2003-03-04 2004-09-30 Abel Systems Inc Surface light emitting device
KR100563046B1 (en) 2003-03-06 2006-03-24 삼성에스디아이 주식회사 Organic electro luminescence display device
JP4822243B2 (en) * 2003-03-25 2011-11-24 国立大学法人京都大学 LIGHT EMITTING ELEMENT AND ORGANIC ELECTROLUMINESCENT LIGHT EMITTING ELEMENT
KR20050121691A (en) 2003-03-25 2005-12-27 교또 다이가꾸 Light-emitting device and organic electroluminescence light-emitting device
US7030555B2 (en) 2003-04-04 2006-04-18 Nitto Denko Corporation Organic electroluminescence device, planar light source and display device using the same
US20040217702A1 (en) * 2003-05-02 2004-11-04 Garner Sean M. Light extraction designs for organic light emitting diodes
KR100667063B1 (en) 2003-05-08 2007-01-10 삼성에스디아이 주식회사 Method of manufacturing a substrate for organic electroluminescent display device
GB2403023A (en) * 2003-06-20 2004-12-22 Sharp Kk Organic light emitting device
KR100546652B1 (en) * 2003-06-30 2006-01-26 엘지전자 주식회사 Organic electro luminescence device
US7126270B2 (en) * 2003-06-30 2006-10-24 Semiconductor Energy Laboratory Co., Ltd. Reflector for a light emitting device
JP2005050708A (en) * 2003-07-29 2005-02-24 Samsung Sdi Co Ltd Substrate for optical elements and organic electroluminescence element as well as organic electroluminescence display device
JP2005063839A (en) 2003-08-13 2005-03-10 Toshiba Matsushita Display Technology Co Ltd Optical device and organic electroluminescent display device
JP2005063838A (en) 2003-08-13 2005-03-10 Toshiba Matsushita Display Technology Co Ltd Optical device and organic el display device
TW200515836A (en) * 2003-10-22 2005-05-01 Hannstar Display Corp Organic electroluminescent element
KR100563059B1 (en) 2003-11-28 2006-03-24 삼성에스디아이 주식회사 Electroluminescence display device and laser induced thermal imaging donor film for the electroluminescence display device
KR20050066970A (en) 2003-12-26 2005-06-30 닛토덴코 가부시키가이샤 Electroluminescence device, planar light source and display using the same
JP5005164B2 (en) 2004-03-03 2012-08-22 株式会社ジャパンディスプレイイースト LIGHT EMITTING ELEMENT, LIGHT EMITTING DISPLAY DEVICE AND LIGHTING DEVICE
JP4968703B2 (en) * 2004-03-03 2012-07-04 ローム株式会社 Organic light emitting device
JP4717882B2 (en) * 2004-06-14 2011-07-06 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ LED with improved emission profile
US7682656B2 (en) * 2004-06-14 2010-03-23 Agruim Inc. Process and apparatus for producing a coated product
TWI285772B (en) * 2004-06-18 2007-08-21 Innolux Display Corp A light guide plate and a backlight module using the same
KR100615234B1 (en) 2004-08-03 2006-08-25 삼성에스디아이 주식회사 Inorganic electroluminescent display device and the method of manufacturing that device
US7540978B2 (en) 2004-08-05 2009-06-02 Novaled Ag Use of an organic matrix material for producing an organic semiconductor material, organic semiconductor material and electronic component
DE102004042461A1 (en) * 2004-08-31 2006-03-30 Novaled Gmbh Top-emitting, electroluminescent device with frequency conversion centers
JP4511440B2 (en) 2004-10-05 2010-07-28 三星モバイルディスプレイ株式會社 ORGANIC LIGHT EMITTING ELEMENT AND METHOD FOR PRODUCING ORGANIC LIGHT EMITTING ELEMENT
EP1648042B1 (en) 2004-10-07 2007-05-02 Novaled AG A method for doping a semiconductor material with cesium
JP2006128011A (en) * 2004-10-29 2006-05-18 Konica Minolta Holdings Inc Surface light emitting device
JP2006114432A (en) * 2004-10-18 2006-04-27 Konica Minolta Holdings Inc Surface emitting element
KR100683693B1 (en) 2004-11-10 2007-02-15 삼성에스디아이 주식회사 Light emitting device
KR100730121B1 (en) 2004-11-29 2007-06-19 삼성에스디아이 주식회사 An organic electroluminescent display device and method for preparing the same
JP4253302B2 (en) 2005-01-06 2009-04-08 株式会社東芝 Organic electroluminescence device and method for producing the same
KR20060081190A (en) * 2005-01-07 2006-07-12 삼성에스디아이 주식회사 An electroluminescent device and a method for preparing the same
US8134291B2 (en) 2005-01-07 2012-03-13 Samsung Mobile Display Co., Ltd. Electroluminescent device and method for preparing the same
JP4410123B2 (en) * 2005-02-10 2010-02-03 株式会社東芝 Organic EL display
JP2006236655A (en) * 2005-02-23 2006-09-07 Konica Minolta Holdings Inc Organic electroluminescent device
JP4517910B2 (en) * 2005-03-24 2010-08-04 コニカミノルタホールディングス株式会社 ORGANIC ELECTROLUMINESCENCE ELEMENT AND LIGHTING DEVICE AND DISPLAY DEVICE PROVIDED WITH SAME
US20060226429A1 (en) * 2005-04-08 2006-10-12 Sigalas Mihail M Method and apparatus for directional organic light emitting diodes
DE502005009415D1 (en) * 2005-05-27 2010-05-27 Novaled Ag Transparent organic light emitting diode
EP2045843B1 (en) * 2005-06-01 2012-08-01 Novaled AG Light-emitting component with an electrode assembly
EP1753048B1 (en) * 2005-08-11 2008-08-20 Novaled AG Method of making a top-emitting element and its use
KR101109195B1 (en) * 2005-12-19 2012-01-30 삼성전자주식회사 Three dimensional light emitting device and preparation method thereof
WO2007077810A1 (en) 2006-01-05 2007-07-12 Konica Minolta Holdings, Inc. Organic electroluminescent device, display and illuminating device
EP1808909A1 (en) * 2006-01-11 2007-07-18 Novaled AG Electroluminescent light-emitting device
EP2001065B1 (en) 2006-03-30 2016-11-09 Konica Minolta Holdings, Inc. Organic electroluminescent device, illuminating device and display device
WO2007119473A1 (en) 2006-03-30 2007-10-25 Konica Minolta Holdings, Inc. Organic electroluminescence element, method for manufacturing organic electroluminescence element, illuminating device and display device
JP4905105B2 (en) * 2006-04-28 2012-03-28 株式会社豊田自動織機 Display device
KR100786469B1 (en) 2006-06-09 2007-12-17 삼성에스디아이 주식회사 Organic light-emitting device and the preparing method of the same
US7973469B2 (en) 2006-09-12 2011-07-05 Konica Minolta Holdings, Inc. Organic electroluminescence element, and illuminating device and display device therewith
JP2008108439A (en) 2006-10-23 2008-05-08 Nec Lighting Ltd Electroluminescent element and electroluminescent panel
WO2008072596A1 (en) 2006-12-13 2008-06-19 Konica Minolta Holdings, Inc. Organic electroluminescent device, display and illuminating device
US8179034B2 (en) 2007-07-13 2012-05-15 3M Innovative Properties Company Light extraction film for organic light emitting diode display and lighting devices
JP5284036B2 (en) 2007-11-14 2013-09-11 キヤノン株式会社 Light emitting device
WO2009064020A1 (en) * 2007-11-14 2009-05-22 Canon Kabushiki Kaisha Light emitting device
WO2009064019A1 (en) * 2007-11-14 2009-05-22 Canon Kabushiki Kaisha Light-emitting apparatus
WO2009079249A1 (en) * 2007-12-14 2009-06-25 3M Innovative Properties Company Methods for making electronic devices
US20090152533A1 (en) * 2007-12-17 2009-06-18 Winston Kong Chan Increasing the external efficiency of light emitting diodes
TW200929593A (en) * 2007-12-20 2009-07-01 Nat Univ Tsing Hua Light source with reflective pattern structure
JP5057076B2 (en) * 2008-03-03 2012-10-24 大日本印刷株式会社 Light extraction structure from light emitting element
JP5214284B2 (en) 2008-03-10 2013-06-19 株式会社東芝 Light extraction layer for light emitting device, and organic electroluminescence element using the same
JP2009259792A (en) * 2008-03-26 2009-11-05 Fujifilm Corp Organic el display device
EP2460866B1 (en) 2008-05-13 2019-12-11 Konica Minolta Holdings, Inc. Organic electroluminescent element, display device and lighting device
JP5288967B2 (en) * 2008-09-22 2013-09-11 ユー・ディー・シー アイルランド リミテッド LIGHT EMITTING ELEMENT, MANUFACTURING METHOD THEREOF, AND DISPLAY HAVING THE LIGHT EMITTING ELEMENT
KR100970482B1 (en) * 2008-12-04 2010-07-16 삼성전자주식회사 Organic light emitting device and method of manufacturing the same
US7957621B2 (en) 2008-12-17 2011-06-07 3M Innovative Properties Company Light extraction film with nanoparticle coatings
JP5472121B2 (en) 2009-01-28 2014-04-16 コニカミノルタ株式会社 ORGANIC ELECTROLUMINESCENT ELEMENT, DISPLAY DEVICE AND LIGHTING DEVICE, AND METHOD FOR PRODUCING ORGANIC ELECTROLUMINESCENT ELEMENT
JP2010182449A (en) 2009-02-03 2010-08-19 Fujifilm Corp Organic electroluminescent display device
WO2010090077A1 (en) 2009-02-06 2010-08-12 コニカミノルタホールディングス株式会社 Organic electroluminescent element, and illumination device and display device each comprising the element
US8686630B2 (en) 2009-02-09 2014-04-01 Konica Minolta Holdings, Inc. Organic electroluminescence element and illumination device using the same
JP5118659B2 (en) * 2009-02-24 2013-01-16 パナソニック株式会社 Light emitting element
JP2010230714A (en) * 2009-03-25 2010-10-14 Fujifilm Corp Optical sheet and method for manufacturing the same
JP5266130B2 (en) * 2009-03-31 2013-08-21 富士フイルム株式会社 Light emitting element
EP2453496B1 (en) 2009-07-07 2018-11-14 Konica Minolta Holdings, Inc. Organic electroluminescent element, novel compound, lighting device and display device
WO2011062215A1 (en) 2009-11-19 2011-05-26 コニカミノルタホールディングス株式会社 Organic electroluminescence element, method for producing organic electroluminescence element, and illumination device using organic electroluminescence element
JP2011154051A (en) * 2010-01-25 2011-08-11 Dainippon Printing Co Ltd Hologram sheet
JP2011154050A (en) * 2010-01-25 2011-08-11 Dainippon Printing Co Ltd Hologram sheet
JP2011222421A (en) * 2010-04-13 2011-11-04 Asahi Kasei E-Materials Corp Light-emitting device
WO2011152496A1 (en) * 2010-06-04 2011-12-08 コニカミノルタホールディングス株式会社 Illumination apparatus
JP2011257651A (en) 2010-06-10 2011-12-22 Canon Inc Light emitting substrate and image display device having the same
JP2012054040A (en) 2010-08-31 2012-03-15 Nitto Denko Corp Organic electroluminescent light-emitting device
KR20130114642A (en) 2010-09-30 2013-10-17 미쯔비시 레이온 가부시끼가이샤 Mold having fine irregular structure on surface, method of producing product having fine irregular structure on surface, use of product, stack expressing heterochromia and surface emitting member
JP5733973B2 (en) * 2010-12-20 2015-06-10 キヤノン株式会社 Light emitting element
EP2677561B1 (en) 2011-02-16 2019-08-07 Konica Minolta, Inc. Organic electroluminescent element, lighting device, and display device
EP2696385A4 (en) 2011-04-07 2014-11-26 Konica Minolta Inc Organic electroluminescent element and lighting device
JPWO2012153603A1 (en) 2011-05-10 2014-07-31 コニカミノルタ株式会社 Phosphorescent light-emitting organic electroluminescence element and lighting device
TWI577523B (en) 2011-06-17 2017-04-11 三菱麗陽股份有限公司 Mold having an uneven structure on its surface, optical article, and manufacturing method thereof, transparent base material for surface light emitter, and surface light emitter
JP5742586B2 (en) 2011-08-25 2015-07-01 コニカミノルタ株式会社 Organic electroluminescence element, lighting device and display device
TWI470814B (en) * 2011-10-25 2015-01-21 Au Optronics Corp Solar cell
JP5895507B2 (en) * 2011-12-19 2016-03-30 大日本印刷株式会社 Optical element and light emitting element and organic electroluminescence element using the same
JP5978843B2 (en) 2012-02-02 2016-08-24 コニカミノルタ株式会社 Iridium complex compound, organic electroluminescence device material, organic electroluminescence device, lighting device and display device
WO2013154150A1 (en) 2012-04-13 2013-10-17 旭化成株式会社 Light extraction body for semiconductor light-emitting element, and light-emitting element
JP5880274B2 (en) 2012-05-21 2016-03-08 コニカミノルタ株式会社 Organic electroluminescence element, lighting device and display device
JP5849867B2 (en) 2012-06-21 2016-02-03 コニカミノルタ株式会社 Organic electroluminescence element, display device and lighting device
JP5889730B2 (en) 2012-06-27 2016-03-22 Lumiotec株式会社 Organic electroluminescent device and lighting device
US20150179958A1 (en) 2012-08-07 2015-06-25 Konica Minolta Inc. Organic electroluminescent element, lighting device and display device
EP2894686B1 (en) 2012-09-04 2018-01-03 Konica Minolta, Inc. Organic electroluminescent element, lighting device and display device
JP5395942B2 (en) * 2012-10-15 2014-01-22 パナソニック株式会社 Light emitting element
KR101995191B1 (en) 2012-12-10 2019-07-02 코니카 미놀타 가부시키가이샤 Material for organic electroluminescent element, organic electroluminescent element, illumination device, and display device
WO2014092014A1 (en) 2012-12-10 2014-06-19 コニカミノルタ株式会社 Organic electroluminescence element, illumination device and display device
US9379359B2 (en) 2013-03-13 2016-06-28 Panasonic Intellectual Property Management Co., Ltd. Organic electroluminescence element and lighting device using same
JP6314599B2 (en) 2013-03-29 2018-04-25 コニカミノルタ株式会社 COMPOUND FOR ORGANIC ELECTROLUMINESCENCE, ORGANIC ELECTROLUMINESCENCE ELEMENT, LIGHTING DEVICE AND DISPLAY DEVICE HAVING THE SAME
KR20150121107A (en) 2013-03-29 2015-10-28 코니카 미놀타 가부시키가이샤 Isomer-mixture metal complex composition, organic electroluminescent element, illuminator, and display device
JP6314974B2 (en) 2013-03-29 2018-04-25 コニカミノルタ株式会社 ORGANIC ELECTROLUMINESCENT ELEMENT, LIGHTING DEVICE, DISPLAY DEVICE, LIGHT EMITTING THIN FILM AND COMPOSITION AND LIGHT EMITTING METHOD
US9324965B2 (en) * 2014-04-22 2016-04-26 Avago Technologies General Ip (Singapore) Pte. Ltd. Method and system for an organic light emitting diode structure
JP6600129B2 (en) * 2014-07-09 2019-10-30 大日本印刷株式会社 Image display device
JP5831654B1 (en) 2015-02-13 2015-12-09 コニカミノルタ株式会社 Aromatic heterocycle derivative, organic electroluminescence device using the same, illumination device and display device
JP2016201257A (en) 2015-04-10 2016-12-01 株式会社ジャパンディスプレイ Method of manufacturing display device
JP6788314B2 (en) 2016-01-06 2020-11-25 コニカミノルタ株式会社 Organic electroluminescence element, manufacturing method of organic electroluminescence element, display device and lighting device

Family Cites Families (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0766856B2 (en) 1986-01-24 1995-07-19 株式会社小松製作所 Thin film EL device
JPS6354184A (en) 1986-08-26 1988-03-08 日建産業株式会社 Tape liner
JP2670572B2 (en) 1987-06-18 1997-10-29 株式会社小松製作所 Thin film EL element
JPH01220394A (en) 1988-02-29 1989-09-04 Hitachi Ltd High-intensity el element
JP2659595B2 (en) 1989-10-18 1997-09-30 株式会社テック Edge emitting EL device
JP3133095B2 (en) 1990-04-25 2001-02-05 兆岐 史 Gastrointestinal sclerosis agent
JPH05264972A (en) * 1992-03-18 1993-10-15 Canon Inc Display element and display device
US6052164A (en) 1993-03-01 2000-04-18 3M Innovative Properties Company Electroluminescent display with brightness enhancement
JP3220884B2 (en) 1993-07-08 2001-10-22 セイコーエプソン株式会社 Display device
JP2931211B2 (en) 1994-09-13 1999-08-09 出光興産株式会社 Organic EL device
JP3584575B2 (en) 1995-10-13 2004-11-04 ソニー株式会社 Optical element
CN1194242C (en) * 1995-11-01 2005-03-23 松下电器产业株式会社 Outgoing efficiency control device, projection type display appts. infrared sensor and non-contact thermometer
US5705285A (en) * 1996-09-03 1998-01-06 Motorola, Inc. Multicolored organic electroluminescent display
JP4073510B2 (en) 1996-12-13 2008-04-09 出光興産株式会社 Organic EL light emitting device
JP3374035B2 (en) 1997-03-21 2003-02-04 三洋電機株式会社 Organic electroluminescence device

Cited By (67)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060286889A1 (en) * 1999-12-15 2006-12-21 Semiconductor Energy Laboratory Co., Ltd. EL display device
US8754577B2 (en) 1999-12-15 2014-06-17 Semiconductor Energy Laboratory Co., Ltd. EL display device
US20110210661A1 (en) * 1999-12-15 2011-09-01 Semiconductor Energy Laboratory Co., Ltd. El display device
US20040056592A1 (en) * 2002-09-25 2004-03-25 Fuji Photo Film Co., Ltd. Light-emitting element
US7699482B2 (en) 2002-09-25 2010-04-20 Fujifilm Corporation Light-emitting element
US7619357B2 (en) 2003-05-22 2009-11-17 Samsung Mobile Display Co., Ltd. Electroluminescent display device
EP1480281A3 (en) * 2003-05-22 2007-08-08 Samsung SDI Co., Ltd. Electroluminescent display device
US20050077820A1 (en) * 2003-05-22 2005-04-14 Yasuharu Onishi Electroluminescent display device
US7696687B2 (en) * 2004-06-26 2010-04-13 Samsung Mobile Display Co., Ltd. Organic electroluminescent display device with nano-porous layer
US20060006778A1 (en) * 2004-06-26 2006-01-12 Joon-Gu Lee Organic electroluminescent display device and method for manufacturing the same
US20060049749A1 (en) * 2004-09-06 2006-03-09 Fuji Photo Film Co., Ltd. Organic electroluminescent device
US7800301B2 (en) 2004-09-06 2010-09-21 Fujifilm Corporation Organic electroluminescent device comprising a prism structure
US7402939B2 (en) * 2004-09-28 2008-07-22 Toshiba Matsushita Display Technology Co., Ltd. Organic EL display
US20060066230A1 (en) * 2004-09-28 2006-03-30 Hirofumi Kubota Organic EL display
US20100118522A1 (en) * 2007-05-02 2010-05-13 Koninklijke Philips Electronics N.V. Light emitting device using oled panels in folded or deployed configuration
US8529114B2 (en) 2007-11-13 2013-09-10 Panasonic Corporation Sheet and light emitting device
CN102393541A (en) * 2007-11-13 2012-03-28 松下电器产业株式会社 Sheet and light-emitting device
US8304788B2 (en) * 2007-11-14 2012-11-06 Canon Kabushiki Kaisha Display apparatus and method of producing same
US8232572B2 (en) 2007-11-14 2012-07-31 Canon Kabushiki Kaisha Light emitting device
US20110101386A1 (en) * 2007-11-14 2011-05-05 Canon Kabushiki Kaisha Display apparatus and method of producing same
US20090160317A1 (en) * 2007-12-21 2009-06-25 Herschel Clement Burstyn Increasing the external efficiency of organic light emitting diodes utilizing a diffraction grating
US20110180823A1 (en) * 2008-09-22 2011-07-28 Yoshihisa Usami Light-emitting device, production method therefor, and display containing the same
CN102257651A (en) * 2008-12-19 2011-11-23 皇家飞利浦电子股份有限公司 Transparent organic light emitting diode
US20110133624A1 (en) * 2008-12-26 2011-06-09 Wakabayashi Shin-Ichi Sheet and light emitting apparatus
US8227966B2 (en) 2008-12-26 2012-07-24 Panasonic Corporation Sheet and light emitting apparatus
US8430539B2 (en) 2009-05-12 2013-04-30 Panasonic Corporation Sheet and light emitting device
US8733983B2 (en) 2009-05-12 2014-05-27 Panasonic Corporation Sheet and light-emitting device
CN102405424A (en) * 2009-05-12 2012-04-04 松下电器产业株式会社 Sheet and light-emitting device
US20110090697A1 (en) * 2009-05-12 2011-04-21 Jyunpei Matsuzaki Sheet and light emitting device
US20110080738A1 (en) * 2009-05-12 2011-04-07 Wakabayashi Shin-Ichi Optical sheet, light-emitting device, and method for manufacturing optical sheet
US20110080737A1 (en) * 2009-05-12 2011-04-07 Seiji Nishiwaki Sheet, light emitting device, and method for producing the sheet
US8475004B2 (en) 2009-05-12 2013-07-02 Panasonic Corporation Optical sheet, light-emitting device, and method for manufacturing optical sheet
US8491160B2 (en) 2009-05-12 2013-07-23 Panasonic Corporation Sheet, light emitting device, and method for producing the sheet
US20100289038A1 (en) * 2009-05-13 2010-11-18 Canon Kabushiki Kaisha Display apparatus
US8482194B2 (en) 2009-05-13 2013-07-09 Canon Kabushiki Kaisha Display apparatus having a circular polarizer
US8283857B2 (en) 2009-07-28 2012-10-09 Canon Kabushiki Kaisha Image display apparatus
US20110025201A1 (en) * 2009-07-28 2011-02-03 Canon Kabushiki Kaisha Image display apparatus
US20120228647A1 (en) * 2009-08-25 2012-09-13 Sumitomo Chemical Company, Limited Organic electroluminescent element
US8294639B2 (en) 2009-12-25 2012-10-23 Canon Kabushiki Kaisha Display unit
US20110156991A1 (en) * 2009-12-25 2011-06-30 Canon Kabushiki Kaisha Display unit
US8669559B2 (en) 2010-04-12 2014-03-11 Canon Kabushiki Kaisha Image display apparatus and image display apparatus manufacturing method
US20140347609A1 (en) * 2011-03-31 2014-11-27 Chi Mei Materials Technology Corporation Display apparatus and liquid crystal display device
US9194545B2 (en) 2011-09-07 2015-11-24 Panasonic Intellectual Property Management Co., Ltd. Light emitting device and light sheet
US9620740B2 (en) 2012-10-11 2017-04-11 Panasonic Intellectual Property Management Co., Ltd. Organic electroluminescence element and lighting device
US9595648B2 (en) 2013-04-12 2017-03-14 Panasonic Intellectual Property Management Co., Ltd. Light-emitting device
US9647240B2 (en) 2013-05-21 2017-05-09 Panasonic Intellectual Property Management Co., Ltd. Light emitting apparatus
JP2015005494A (en) * 2013-05-22 2015-01-08 パナソニックIpマネジメント株式会社 Light extraction substrate of organic el illumination
US9515239B2 (en) 2014-02-28 2016-12-06 Panasonic Intellectual Property Management Co., Ltd. Light-emitting device and light-emitting apparatus
US9618697B2 (en) 2014-02-28 2017-04-11 Panasonic Intellectual Property Management Co., Ltd. Light directional angle control for light-emitting device and light-emitting apparatus
US9880336B2 (en) 2014-02-28 2018-01-30 Panasonic Intellectual Property Management Co., Ltd. Light-emitting device including photoluminescent layer
US9890912B2 (en) 2014-02-28 2018-02-13 Panasonic Intellectual Property Management Co., Ltd. Light-emitting apparatus including photoluminescent layer
US9518215B2 (en) 2014-02-28 2016-12-13 Panasonic Intellectual Property Management Co., Ltd. Light-emitting device and light-emitting apparatus
US10012780B2 (en) 2014-02-28 2018-07-03 Panasonic Intellectual Property Management Co., Ltd. Light-emitting device including photoluminescent layer
CN103928635A (en) * 2014-04-18 2014-07-16 上海和辉光电有限公司 OLED device anode structure
WO2016144779A1 (en) * 2015-03-06 2016-09-15 Massachusetts Institute Of Technology Systems, methods, and apparatus for radiation detection
US9810578B2 (en) 2015-03-06 2017-11-07 Massachusetts Institute Of Technology Systems, methods, and apparatus for radiation detection
US10113712B2 (en) 2015-03-13 2018-10-30 Panasonic Intellectual Property Management Co., Ltd. Light-emitting device including photoluminescent layer
USRE49093E1 (en) 2015-03-13 2022-06-07 Panasonic Intellectual Property Management Co., Ltd. Light-emitting apparatus including photoluminescent layer
US10031276B2 (en) 2015-03-13 2018-07-24 Panasonic Intellectual Property Management Co., Ltd. Display apparatus including photoluminescent layer
US10182702B2 (en) 2015-03-13 2019-01-22 Panasonic Intellectual Property Management Co., Ltd. Light-emitting apparatus including photoluminescent layer
US9899577B2 (en) 2015-06-08 2018-02-20 Panasonic Intellectual Property Management Co., Ltd. Light-emitting apparatus including photoluminescent layer
US10115874B2 (en) 2015-06-08 2018-10-30 Panasonic Intellectual Property Management Co., Ltd. Light-emitting device including photoluminescent layer
US10359155B2 (en) 2015-08-20 2019-07-23 Panasonic Intellectual Property Management Co., Ltd. Light-emitting apparatus
US9882100B2 (en) 2015-08-20 2018-01-30 Panasonic Intellectual Property Management Co., Ltd. Light-emitting device having surface structure for limiting directional angle of light
US10094522B2 (en) 2016-03-30 2018-10-09 Panasonic Intellectual Property Management Co., Ltd. Light-emitting device having photoluminescent layer
US20210408424A1 (en) * 2020-11-05 2021-12-30 Anhui University Perovskite light-emitting diode with adjustable light field
US11758748B2 (en) * 2020-11-05 2023-09-12 Anhui University Perovskite light-emitting diode with adjustable light field

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