WO2009093426A1 - Light emitting element and display device - Google Patents

Light emitting element and display device Download PDF

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Publication number
WO2009093426A1
WO2009093426A1 PCT/JP2009/000146 JP2009000146W WO2009093426A1 WO 2009093426 A1 WO2009093426 A1 WO 2009093426A1 JP 2009000146 W JP2009000146 W JP 2009000146W WO 2009093426 A1 WO2009093426 A1 WO 2009093426A1
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Prior art keywords
light
light emitting
color conversion
layer
conversion layer
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PCT/JP2009/000146
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French (fr)
Japanese (ja)
Inventor
Takashi Ohta
Noriyuki Matsusue
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Panasonic Corporation
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Publication of WO2009093426A1 publication Critical patent/WO2009093426A1/en

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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/30—Devices specially adapted for multicolour light emission
    • H10K59/38—Devices specially adapted for multicolour light emission comprising colour filters or colour changing media [CCM]
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/80—Constructional details
    • H10K59/875—Arrangements for extracting light from the devices
    • H10K59/878—Arrangements for extracting light from the devices comprising reflective means
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K2102/00—Constructional details relating to the organic devices covered by this subclass
    • H10K2102/301—Details of OLEDs
    • H10K2102/302—Details of OLEDs of OLED structures
    • H10K2102/3023—Direction of light emission
    • H10K2102/3026—Top emission

Definitions

  • the present invention relates to a light emitting element, and more particularly to an organic EL light emitting element used for a flat display or the like.
  • a configuration in which light emitting elements that emit blue, green, and red light are arranged as a full color display device using organic EL light emitting elements has been proposed.
  • a configuration is proposed in which a configuration of a light-emitting element in which a transparent electrode, an organic EL layer, and a reflective electrode are sequentially arranged directly on a transparent substrate is employed, and a color conversion layer is provided on the light emitting side.
  • a configuration of a light-emitting element in which a transparent electrode, an organic EL layer, and a reflective electrode are sequentially arranged directly on a transparent substrate is employed, and a color conversion layer is provided on the light emitting side.
  • an organic EL light emitting device having a resonator structure with two electrodes, by providing a color conversion layer, components in an unnecessary wavelength region of the emitted color are reduced and the color purity of extracted light is improved. There is a way.
  • the color conversion layer has been provided on the light emitting side.
  • a light emitting element in which a light reflecting layer 52, an electrode 54, an organic EL layer 55, and a transparent electrode 56 are sequentially laminated on a substrate 51, and a substrate in which a color conversion layer 53 is disposed on a glass substrate; When the two are bonded together, a positional shift occurs between the color conversion layer 53 and the light emitting element, which causes a reduction in light extraction efficiency.
  • An object of the present invention is to provide an organic EL light emitting element capable of improving the light extraction efficiency and capable of displaying with excellent color reproducibility, and an organic EL display device using the same.
  • the light emitting device includes a light reflection layer, A first color conversion layer provided on the light reflecting layer; A first electrode provided on the first color conversion layer; A light emitting layer provided on the first electrode; A second electrode provided on the light emitting layer; With Light is extracted from the second electrode.
  • the second electrode may be translucent with respect to light emitted from the light emitting layer and transparent with respect to light subjected to color conversion in the first color conversion layer.
  • the first electrode may be transparent for each of light emitted from the light emitting layer and light color-converted by the first color conversion layer.
  • the light reflecting layer may be selected from the group of aluminum, magnesium, gold, silver, copper, chromium, nickel, palladium, neodymium, molybdenum and alloys containing one or more of these.
  • the first color conversion layer may be selected from the group of a coloring filter, a dichroic filter, and a bandpass filter.
  • the first color conversion layer may contain a fluorescent dye.
  • the light emitting layer may have a laminated structure.
  • the first color conversion layer may be configured separately for each pixel.
  • the first color conversion layer may be formed of the same film thickness and the same material for each pixel, or may be formed of a different film thickness or a different material for each pixel.
  • both the first color conversion layer and the light reflection layer may be configured separately for each pixel.
  • both the first color conversion layer and the light reflection layer may be formed of the same film thickness and the same material for each pixel.
  • the first color conversion layer may be configured in common over a plurality of pixels.
  • a second color conversion layer provided on the second electrode may be further provided.
  • the second color conversion layer is separated for each pixel.
  • the light-emitting element according to the present invention can be used for a passive matrix display device. Furthermore, the light-emitting element according to the present invention can be used for an active matrix display device.
  • the first color conversion layer is provided not on the light extraction side but on the light reflection layer side when viewed from the light emitting layer.
  • a color conversion layer is provided on the light extraction side, so that sufficient color conversion efficiency cannot be obtained.
  • the light emitting element of the present invention the light emitted from the light emitting layer undergoes color conversion for a part thereof in the first color conversion layer, and the light reflected by the light reflecting layer is the first color conversion layer. Pass again. Therefore, since light passes through the first color conversion layer twice or more, the color conversion efficiency can be improved.
  • an organic EL light emitting element capable of displaying with improved light extraction efficiency and excellent color reproducibility, and an organic EL display device using the same can be provided. Further, by performing a series of processes of sequentially laminating the first electrode, the organic EL layer, and the second electrode on the first color conversion layer, it is possible to suppress the displacement of the first color conversion layer. And the light extraction efficiency can be improved. Furthermore, since the light emitting layer is provided after the first color conversion layer is disposed, it is possible to prevent the material used for the first color conversion layer from entering the light emitting layer.
  • FIG. 1 is a cross-sectional view illustrating a configuration of a light-emitting element 10 according to Embodiment 1 of the present invention.
  • a light reflecting layer 12 is formed on a substrate 11.
  • a first color conversion layer 13 is formed on the light reflection layer 12.
  • a first electrode 14 is formed on the first color conversion layer 13.
  • a light emitting layer 15 having a multilayer structure including an organic EL layer is formed on the first electrode 14.
  • the light emitting layer 15 is configured by sequentially laminating an electron transport layer, an organic EL layer, and a hole transport layer in order from the first electrode 14 side (not shown).
  • a second electrode 16 is provided on the light emitting layer 15.
  • the light emitting element 10 is a top emission type that extracts light from the second electrode 16 side opposite to the first color conversion layer 13.
  • This light emitting element 10 is characterized in that the first color conversion layer 13 is provided on the light reflecting layer 12 side, not on the light extraction side as viewed from the light emitting layer 15. Of the light emitted from the light emitting layer 15, the light emitted downward is color-converted by the first color conversion layer 13, reflected by the light reflection layer 12, the first color conversion layer 13, and the first electrode 14. The light-emitting layer 15 and the second electrode 16 are transmitted through and emitted upward.
  • a part of the light emitted upward from the light emitting layer 15 passes through the second electrode 16 as it is and is emitted upward, and another part of the light emitted upward from the light emitting layer 15 is reflected downward, so that the first The color conversion layer 13 performs color conversion, is reflected by the light reflection layer 12, passes through the second electrode 16, and exits upward.
  • the light emitting element 10 the light emitted from the light emitting layer 15 undergoes color conversion for a part thereof by the first color conversion layer 13, and the light reflected by the light reflecting layer 12 passes through the first color conversion layer 13. Pass again. Therefore, since light passes through the first color conversion layer 13 twice, color conversion efficiency can be improved.
  • the first color conversion layer 13 between the light reflection layer 12 and the first electrode 14, it is possible to suppress a decrease in extraction efficiency of light extracted from the light emitting layer 15.
  • the material used for the first color conversion layer 13 can be prevented from entering the light emitting layer 15.
  • the color conversion layer 53 is provided with an object to absorb unnecessary wavelength region components, and therefore the color conversion layer 53 is provided on the light extraction side. It was. Therefore, there is no known arrangement in which the first color conversion layer 13 is provided on the light reflecting layer 12 side like the light emitting element 10 according to Embodiment 1 of the present application, and the opposite side to the light extraction side. Conventionally, it has not been considered at all to arrange a color conversion layer.
  • the second electrode 16 is preferably translucent for light emitted from the light emitting layer 15 and transparent for light color-converted by the first color conversion layer 13.
  • the wavelength selectivity of the extracted light can be improved by allowing the second electrode 16 to selectively transmit the light whose color has been converted by the first color conversion layer 13.
  • each structural member which comprises this light emitting element 10 is demonstrated.
  • the substrate 11 glass plates such as soda glass, non-fluorescent glass, phosphoric acid glass, boric acid glass, quartz, acrylic resin, styrene resin, polycarbonate resin, epoxy resin, polyethylene, polyester, silicone resin, etc.
  • a plastic plate and a plastic film, a metal plate such as alumina, and a metal foil can be used.
  • the substrate 11 is required to be a transparent substrate such as a glass substrate.
  • the light reflecting layer 12 is made of magnesium, silver, or an alloy thereof.
  • the light reflecting layer 12 may be selected from the group of aluminum, magnesium, gold, silver, copper, chromium, nickel, palladium, neodymium, molybdenum and alloys containing one or more of these.
  • the light reflecting layer 12 preferably has a thickness of 5 to 50 nm.
  • the first color conversion layer 13 has a function of transmitting part of the light emitted from the light emitting layer 15, absorbing part of the light, and emitting light having a wavelength (color) different from the absorbed wavelength (color).
  • a colored transparent filter, a dichroic mirror, a band pass filter, or the like can be used as the first color conversion layer 13 .
  • the constituent material of the first color conversion layer 13 include organic pigments, particle-added organic pigments, metal oxides, resins containing the metal oxides, inorganic or organic fluorescent dyes, and the like.
  • the first electrode 14 is made of a conductive material having sufficient translucency with respect to the light generated in the light emitting layer 15.
  • the first electrode 14 is preferably transparent for each of the light emitted from the light emitting layer 15 and the light color-converted by the first color conversion layer 13.
  • the light emitting layer 15 is not limited to a single layer and may have a multilayer structure.
  • the light emitting layer may include an organic EL layer containing an organic light emitter. Furthermore, an electron transport layer and a hole transport layer that sandwich the organic EL layer may be further included. Furthermore, an electron injection layer and / or a hole injection layer may be provided.
  • the electron injection layer and the hole injection layer can be formed by vapor deposition, spin coating, casting, or the like.
  • Electrode transporting layer having electron transporting ability
  • the electron transporting layer having electron transporting ability include nitro-substituted fluorenone derivatives, thiopyrandioxide derivatives, diphequinone derivatives, perylene tetracarboxyl derivatives, anthraquinodimethane derivatives, fluorenylidenes described in JP-A-5-163488.
  • Compounds such as methane derivatives, anthrone derivatives, oxadiazole derivatives, perinone derivatives, quinoline complex derivatives, and the like can be used.
  • Organic EL layer Specific examples include oxinoid compounds, perylene compounds, coumarin compounds, azacoumarin compounds, oxazole compounds, oxadiazole compounds, perinone compounds, pyrrolopyrrole compounds, naphthalene compounds, anthracenes described in JP-A-5-163488.
  • hole transport layer Specific examples include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives described in JP-A-5-163488.
  • Amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, porphyrin compounds, aromatic tertiary amine compounds and styrylamine compounds, butadiene compounds, polystyrene derivatives, hydrazone derivatives, triphenylmethane derivatives, Tetraphenylbenzine derivatives and the like can be used, but particularly preferably, porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds A.
  • the second electrode 16 is preferably made of a conductive material that transmits only light of a specific wavelength with respect to the light generated in the light emitting layer 15. Further, the light emitted from the light emitting layer 15 may be translucent, and the light subjected to color conversion by the first color conversion layer 13 may be transparent. By allowing the second electrode 16 to selectively transmit the light whose color has been converted by the first color conversion layer 13, the wavelength selectivity of the light extracted from the second electrode 16 can be improved.
  • a material constituting the second electrode 16 indium tin oxide (ITO), indium zinc oxide (IZO), or the like is preferable. This is because good conductivity can be obtained even if the film is formed at room temperature.
  • FIG. 2 is a cross-sectional view showing the configuration of the light-emitting element 20 according to Embodiment 2 of the present invention.
  • the light emitting element 20 is a bottom emission type in which the light extraction direction is opposite to that of the light emitting element according to Embodiment 1, and the light emission is extracted from the bottom substrate 11 side. Accordingly, the light emitting element 20 is different in that the arrangement is changed so that the light reflecting layer 12 and the first color conversion layer 13 are provided on the upper portion. In this case, since light is extracted from the bottom substrate 11 side, the substrate 11 needs to be a transparent substrate.
  • Example 1 About the organic EL element 10 which concerns on Example 1 of this invention, the optical simulation was performed on condition of the following.
  • an AgPdCu alloy (abbreviation: APC) was used as a light reflection layer.
  • APC AgPdCu alloy
  • 120 nm of ITO 20 nm of electron injection layer, 80 nm of light emitting layer, hole injection layer
  • FIG. 3 and 4 show the optical simulation results regarding the light emission from the light emitting layer.
  • FIG. 3 is a graph showing the relationship between the light extraction efficiency and the thickness of the color filter (CF) as the first color conversion layer.
  • FIG. 4 is a graph showing the relationship of the angle color difference ( ⁇ uv) with respect to the thickness of the color filter (CF) for each of the observation angles of 65 degrees and 85 degrees.
  • ⁇ uv angle color difference
  • the light extraction efficiency is improved by providing a color filter with a thickness of 110 nm on the light reflection layer.
  • the change in the angular color difference ( ⁇ uv) on the coordinates is very small due to the deviation of the viewing angle from the front toward the oblique direction.
  • the observation angle is a line connecting the observation point and the center of the surface of the light-emitting layer 15 with a line passing through the center of the surface of the light-emitting layer 15 and perpendicular to the surface of the light-emitting layer 15 as an axis (0 degree).
  • the angle X formed by the axis In FIG. 1, the angle X is shown on the surface of the second electrode 16 on the light extraction side. However, considering that the film thickness is smaller than the distance to the observation point, they are substantially the same angle. Can be considered. Further, the angle color difference ( ⁇ uv) at the observation angle X degrees can be obtained by the following equation.
  • uX and vX are u value and v value when an emission spectrum with a wavelength of 380 to 780 nm is measured at an observation angle of X degrees.
  • U0 and v0 are the u value and the v value when the emission spectrum with a wavelength of 380 to 780 nm is measured at an observation angle of 0 degree.
  • FIG. 5 is a cross-sectional view showing the configuration of the light emitting element 30 according to Embodiment 3 of the present invention.
  • the light emitting element 30 is different from the light emitting element 10 according to the first embodiment in that one pixel includes a plurality of subpixels (pixels) having R, G, and B as emission colors.
  • a light reflecting layer 12 is formed on the substrate 11.
  • first color conversion layers 13B, 13G, and 13R are formed for each pixel.
  • a first electrode 14 is formed on the first color conversion layers 13B, 13G, and 13R. Note that the first color conversion layers 13B, 13G, and 13R may have the same thickness for each pixel.
  • light emitting layers 15B, 15G, and 15R having a multilayer structure including an organic EL layer are formed on the first electrode.
  • the light emitting layers 15B, 15G, and 15R are configured by sequentially laminating an electron transport layer, an organic EL layer, and a hole transport layer from the first electrode 14 side (not shown).
  • a second electrode 16 is provided on the light emitting layers 15B, 15G, and 15R.
  • the light emitting element 30 is a top emission type in which light is extracted from the second electrode 16 side opposite to the first color conversion layer 13.
  • the thickness of the laminated structure is set equal for each subpixel.
  • the viewing angle of the organic EL display device is sufficiently expanded, and the organic EL light-emitting element that hardly causes a decrease in contrast due to a change in viewing angle, a hue change, and the like An organic EL display device using the same can be provided (not shown).
  • This light emitting element 30 is characterized in that the first color conversion layers 13B, 13G, and 13R are provided not on the light extraction side from the light emitting layers 15B, 15G, and 15R but on the light reflection layer 12 side.
  • the first color conversion layers 13B, 13G, 13R, the first electrode 14, the light emitting layers 15B, 15G, 15R, and the second electrode 16 are transmitted and emitted upward.
  • a part of the light emitted upward from the light emitting layers 15B, 15G, and 15R passes through the second electrode 16 as it is and is emitted upward, and part of the light is reflected downward, and the first color conversion layers 13B, 13G, The color is converted by 13R, is reflected by the light reflecting layer 12, passes through the second electrode 16, and is emitted upward.
  • the light emitted from the light emitting layers 15B, 15G, and 15R undergoes color conversion for some of the first color conversion layers 13B, 13G, and 13R, and the light reflected by the light reflecting layer 12 is reflected. It passes through the first color conversion layers 13B, 13G, and 13R again. Therefore, since light passes through the first color conversion layers 13B, 13G, and 13R twice, color conversion efficiency can be improved. Further, by disposing the first color conversion layers 13B, 13G, and 13R between the light reflecting layer 12 and the first electrode 14, it is possible to suppress a decrease in extraction efficiency of light extracted from the light emitting layers 15B, 15G, and 15R. be able to. In addition, the material used for the first color conversion layers 13B, 13G, and 13R can be prevented from entering the light-emitting layers 15B, 15G, and 15R.
  • FIG. 6 is a cross-sectional view showing the configuration of the light emitting element 40 according to Embodiment 4 of the present invention.
  • the light emitting element 40 is different from the light emitting element 30 according to Embodiment 3 in that the first color conversion layer 13 is configured in common over a plurality of pixels (blue, green, red). Therefore, in the present embodiment, the first color conversion layer 13 is made of the same material over a plurality of pixels.
  • the first color conversion layer 13 that is common to a plurality of pixels is a material having selective transparency for each wavelength band of blue, green, red extracted from each pixel, for example, It is preferable to use a three-wavelength filter or the like.
  • the first color conversion layer 13 only needs to be continuous over each pixel, and may have irregularities between the pixels as shown in FIG. Further, the first color conversion layer 13 may have a different thickness for each pixel or the same thickness. Further, the first color conversion layer 13 may be flush with the entire pixel.
  • the first color conversion layer 13 is configured in common over a plurality of pixels, whereby the manufacturing process can be simplified.
  • FIG. 7 is a cross-sectional view showing a configuration of the light emitting element 50 according to Embodiment 5 of the present invention.
  • the light-emitting element 50 is provided with second color conversion layers 17B, 17G, and 17R that are configured separately for each pixel on the second electrode 16. It is different in point.
  • a light reflecting layer 12 is formed on the substrate 11.
  • first color conversion layers 13B, 13G, and 13R are formed for each pixel.
  • a first electrode 14 is formed on the first color conversion layers 13B, 13G, and 13R.
  • light emitting layers 15B, 15G, and 15R having a multilayer structure including an organic EL layer are formed on the first electrode.
  • the light emitting layers 15B, 15G, and 15R are configured by sequentially laminating an electron transport layer, an organic EL layer, and a hole transport layer in this order from the first electrode 14 side (not shown).
  • a second electrode 16 is provided on the light emitting layers 15B, 15G, and 15R.
  • second color conversion layers 17B, 17G, and 17R provided for each pixel on the second electrode 16 are provided.
  • the light emitting element 50 is a top emission type in which light is extracted from the second electrode 16 side opposite to the first color conversion layers 13B, 13G, and 13R.
  • the second color conversion layers 17B, 17G, and 17R are provided on the light extraction side when viewed from the light emitting layers 15B, 15G, and 15R, but also the first color conversion on the light reflection layer 12 side.
  • Layers 13B, 13G, and 13R are provided. Of the light emitted from the light emitting layers 15B, 15G, and 15R, the light emitted downward is color-converted by the first color conversion layers 13B, 13G, and 13R, reflected by the light reflecting layer 12, and then the first color conversion layer.
  • the light passes through 13B, 13G, and 13R, the first electrode 14, the light emitting layers 15B, 15G, and 15R, the second electrode 16, and the second color conversion layers 17B, 17G, and 17R, and is emitted upward.
  • a part of the light emitted upward from the light emitting layer 15 is transmitted through the second electrode 16 and the second color conversion layers 17B, 17G, and 17R to be emitted upward, and emitted upward from the light emitting layers 15B, 15G, and 15R.
  • the other part of the reflected light is reflected downward, color-converted by the first color conversion layers 13B, 13G, and 13R, reflected by the light reflection layer 12, and the second electrode 16 and the second color conversion layer.
  • the light passes through 17B, 17G, and 17R and is emitted upward.
  • the light emitted from the light emitting layers 15B, 15G, and 15R undergoes color conversion for a part thereof by the first color conversion layers 13B, 13G, and 13R, and is reflected by the light reflecting layer 12. Passes again through the first color conversion layers 13B, 13G, and 13R.
  • the reflected light passing through the multilayer light emitting layers 15B, 15G, and 15R and the light emitted from the light emitting layers 15B, 15G, and 15R toward the second electrode 16 are the second color conversion layers 17B, 17G, and 17R. And the color conversion efficiency can be further improved.
  • first color conversion layers 13B, 13G, and 13R between the light reflecting layer 12 and the first electrode 14, it is possible to suppress a decrease in extraction efficiency of light extracted from the light emitting layers 15B, 15G, and 15R. be able to.
  • the material used for the first color conversion layers 13B, 13G, and 13R can be prevented from entering the light-emitting layers 15B, 15G, and 15R.
  • FIG. 8 is a cross-sectional view showing the configuration of the light emitting element 60 according to Embodiment 6 of the present invention.
  • the light emitting element 60 is different from the light emitting element 50 according to the fifth embodiment in that the first color conversion layer 13 is configured in common over a plurality of pixels (blue, green, red). Therefore, in the present embodiment, the first color conversion layer 13 is made of the same material over a plurality of pixels.
  • the first color conversion layer 13 that is common to a plurality of pixels (blue, green, red) is a material having selective transparency for each wavelength band of blue, green, red extracted from each pixel, for example, It is preferable to use a three-wavelength filter or the like.
  • the first color conversion layer 13 only needs to be continuous over each pixel, and may have irregularities between the pixels as shown in FIG. Further, the first color conversion layer 13 may have a different thickness for each pixel or the same thickness. Further, the first color conversion layer 13 may be flush with the entire pixel.
  • the first color conversion layer 13 is configured in common over a plurality of pixels, whereby the manufacturing process can be simplified.
  • the present invention can be used for organic EL display devices used for flat light sources, flat displays, and the like.

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  • Electroluminescent Light Sources (AREA)

Abstract

A light emitting element is provided with a light reflecting layer; a first color conversion layer arranged on the light reflecting layer; a first electrode arranged on the color conversion layer; a light emitting layer arranged on the first electrode; and a second electrode arranged on the light emitting layer. The light emitting element extracts light from the second electrode.

Description

発光素子および表示装置LIGHT EMITTING ELEMENT AND DISPLAY DEVICE
　本発明は、発光素子に関し、特にフラットディスプレイなどに用いられる有機ＥＬ発光素子に関する。 The present invention relates to a light emitting element, and more particularly to an organic EL light emitting element used for a flat display or the like.
　有機ＥＬ発光素子を用いた表示装置をフルカラー化する構成としては、青、緑、赤に発光する発光素子を配列した構成が提案されている。この構成において、透明基板の上に直接配置された透明電極、有機ＥＬ層および反射電極を順次積層した発光素子の構成を採用し、光出射側に色変換層を設けた構成が提案されている（例えば、特許文献１参照）。 A configuration in which light emitting elements that emit blue, green, and red light are arranged as a full color display device using organic EL light emitting elements has been proposed. In this configuration, a configuration is proposed in which a configuration of a light-emitting element in which a transparent electrode, an organic EL layer, and a reflective electrode are sequentially arranged directly on a transparent substrate is employed, and a color conversion layer is provided on the light emitting side. (For example, refer to Patent Document 1).
　また、透明基板の上に直接配置された反射電極、有機ＥＬ層および透明電極を順次積層した発光素子の構成を採用し、前記透明電極の上に色変換層を設けた構成が提案されている（例えば、特許文献２参照）。 In addition, a configuration is proposed in which a configuration of a light-emitting element in which a reflective electrode, an organic EL layer, and a transparent electrode arranged directly on a transparent substrate are sequentially stacked and a color conversion layer is provided on the transparent electrode is proposed. (For example, refer to Patent Document 2).
　また、透明基板の上に直接配置された反射電極、透明導電層、有機ＥＬ層および透明電極を順次積層した発光素子の構成を採用し、前記透明電極の上に色変換層を設けた構成が提案されている（例えば、特許文献３参照）。 In addition, a configuration of a light emitting device in which a reflective electrode, a transparent conductive layer, an organic EL layer, and a transparent electrode arranged directly on a transparent substrate are sequentially laminated, and a color conversion layer is provided on the transparent electrode is provided. It has been proposed (see, for example, Patent Document 3).
特開平６－１３２０８１号公報JP-A-6-132081 特開２０００－１９５６７０号公報JP 2000-195670 A 特開２００５－１１６５１６号公報JP-A-2005-116516
　現在、２つの電極を備えた共振器構造を備えた有機ＥＬ発光素子において、色変換層を備えることにより、発光色の不要な波長領域の成分を減少させ、取り出される光の色純度を向上させる方法がある。 At present, in an organic EL light emitting device having a resonator structure with two electrodes, by providing a color conversion layer, components in an unnecessary wavelength region of the emitted color are reduced and the color purity of extracted light is improved. There is a way.
　しかしながら、光出射側に色変換層を備えることにより不要な波長領域の成分を吸収するため、光取出し効率が低下しやすく、高輝度の発光素子を実現するには消費電力や素子寿命にとって負荷が大きいといった問題がある。 However, the provision of a color conversion layer on the light emitting side absorbs unnecessary wavelength region components, so that the light extraction efficiency is likely to decrease, and a high luminance light emitting element is a burden on power consumption and element life. There is a problem of being big.
　また、従来、色変換層を発光素子に設けることは不要な波長領域の成分を吸収するということが目的であるため、色変換層は光出射側に設けられていた。また、図９に示すように、基板５１上に、光反射層５２、電極５４、有機ＥＬ層５５、透明電極５６を順次積層した発光素子と色変換層５３をガラス基板上に配置した基板とを張り合わせた場合、色変換層５３と発光素子の間に位置ずれが生じ、光取り出し効率を低下させる要因となっていた。 Conventionally, since the purpose of providing the color conversion layer in the light emitting element is to absorb components in an unnecessary wavelength region, the color conversion layer has been provided on the light emitting side. Further, as shown in FIG. 9, a light emitting element in which a light reflecting layer 52, an electrode 54, an organic EL layer 55, and a transparent electrode 56 are sequentially laminated on a substrate 51, and a substrate in which a color conversion layer 53 is disposed on a glass substrate; When the two are bonded together, a positional shift occurs between the color conversion layer 53 and the light emitting element, which causes a reduction in light extraction efficiency.
　本発明の目的は、光取出し効率を向上させ、かつ色再現性に優れた表示が可能な有機ＥＬ発光素子およびそれを用いた有機ＥＬ表示装置を提供することである。 An object of the present invention is to provide an organic EL light emitting element capable of improving the light extraction efficiency and capable of displaying with excellent color reproducibility, and an organic EL display device using the same.
　本発明に係る発光素子は、光反射層と、
　前記光反射層の上に設けられた第１の色変換層と、
　前記第１の色変換層の上に設けられた第１の電極と、
　前記第１の電極の上に設けられた発光層と、
　前記発光層の上に設けられた第２の電極と、
を備え、
　前記第２の電極から光を取り出すことを特徴とする。 The light emitting device according to the present invention includes a light reflection layer,
A first color conversion layer provided on the light reflecting layer;
A first electrode provided on the first color conversion layer;
A light emitting layer provided on the first electrode;
A second electrode provided on the light emitting layer;
With
Light is extracted from the second electrode.
　また、前記第２の電極は、前記発光層から発光する光について半透明であって、前記第１の色変換層で色変換された光について透明であってもよい。 Further, the second electrode may be translucent with respect to light emitted from the light emitting layer and transparent with respect to light subjected to color conversion in the first color conversion layer.
　さらに、前記第１の電極は、前記発光層から発光する光、及び、前記第１の色変換層で色変換された光のそれぞれについて透明であってもよい。 Furthermore, the first electrode may be transparent for each of light emitted from the light emitting layer and light color-converted by the first color conversion layer.
　さらに、前記光反射層は、アルミニウム、マグネシウム、金、銀、銅、クロム、ニッケル、パラジウム、ネオジウム、モリブデンおよびこれらの１種類以上を含む合金の群から選ばれるものであってもよい。 Furthermore, the light reflecting layer may be selected from the group of aluminum, magnesium, gold, silver, copper, chromium, nickel, palladium, neodymium, molybdenum and alloys containing one or more of these.
　またさらに、前記第１の色変換層は、着色フィルタ、ダイクロイックフィルタおよびバンドパスフィルタの群から選ばれるものであってもよい。前記第１の色変換層は、蛍光色素を含有してもよい。 Furthermore, the first color conversion layer may be selected from the group of a coloring filter, a dichroic filter, and a bandpass filter. The first color conversion layer may contain a fluorescent dye.
　また、前記発光層は、積層構造を有するものであってもよい。 The light emitting layer may have a laminated structure.
　さらに、前記第１の色変換層は、画素毎に分離して構成されていてもよい。この場合、前記第１の色変換層は、画素毎に同じ膜厚及び同じ材料で構成されていてもよく、あるいは、画素毎に異なる膜厚、又は、異なる材料で構成されていてもよい。 Furthermore, the first color conversion layer may be configured separately for each pixel. In this case, the first color conversion layer may be formed of the same film thickness and the same material for each pixel, or may be formed of a different film thickness or a different material for each pixel.
　さらに、前記第１の色変換層と前記光反射層の両方は、画素毎に分離して構成されていてもよい。この場合、前記第１の色変換層と前記光反射層の両方は、画素毎にそれぞれ同じ膜厚及び同じ材料で構成されていてもよい。 Furthermore, both the first color conversion layer and the light reflection layer may be configured separately for each pixel. In this case, both the first color conversion layer and the light reflection layer may be formed of the same film thickness and the same material for each pixel.
　さらに、前記第１の色変換層は、複数の画素にわたって共通に構成されていてもよい。 Furthermore, the first color conversion layer may be configured in common over a plurality of pixels.
　また、前記第２の電極の上に設けられた第２の色変換層をさらに備えていてもよい。この場合、前記第２の色変換層は画素毎に分離して構成されている。 Further, a second color conversion layer provided on the second electrode may be further provided. In this case, the second color conversion layer is separated for each pixel.
　また、本発明に係る発光素子は、パッシブマトリクス型表示装置に用いることができる。さらに、本発明に係る発光素子は、アクティブマトリクス型表示装置に用いることができる。 Further, the light-emitting element according to the present invention can be used for a passive matrix display device. Furthermore, the light-emitting element according to the present invention can be used for an active matrix display device.
　本発明に係る発光素子によれば、第１の色変換層を発光層から見て光取り出し側ではなく光反射層側に設けている。従来、光取り出し側に色変換層を設けていたので、光は色変換層を１回しか通過しないため十分に色変換効率が得られなかった。これに対して本願発明の発光素子によれば、発光層から発光した光は第１の色変換層でその一部について色変換を受け、光反射層で反射した光が第１の色変換層を再度通過する。そのため、第１の色変換層を光が２回以上通過するので色変換効率を向上させることができる。そこで、このような発光素子を用いれば光取り出し効率を向上させた、かつ色再現性に優れた表示が可能な有機ＥＬ発光素子およびそれを用いた有機ＥＬ表示装置を提供できる。また、第１の色変換層の上に第１の電極、有機ＥＬ層、第２の電極を順次積層する一連のプロセスを行うことにより、第１の色変換層の位置ずれを抑止することができ、光取り出し効率を向上させることができる。さらに、第１の色変換層を配置した後で発光層を設けるので、第１の色変換層に用いた材料の発光層への侵入を阻止することができる。 According to the light emitting device according to the present invention, the first color conversion layer is provided not on the light extraction side but on the light reflection layer side when viewed from the light emitting layer. Conventionally, since a color conversion layer is provided on the light extraction side, light passes through the color conversion layer only once, so that sufficient color conversion efficiency cannot be obtained. On the other hand, according to the light emitting element of the present invention, the light emitted from the light emitting layer undergoes color conversion for a part thereof in the first color conversion layer, and the light reflected by the light reflecting layer is the first color conversion layer. Pass again. Therefore, since light passes through the first color conversion layer twice or more, the color conversion efficiency can be improved. Therefore, by using such a light emitting element, an organic EL light emitting element capable of displaying with improved light extraction efficiency and excellent color reproducibility, and an organic EL display device using the same can be provided. Further, by performing a series of processes of sequentially laminating the first electrode, the organic EL layer, and the second electrode on the first color conversion layer, it is possible to suppress the displacement of the first color conversion layer. And the light extraction efficiency can be improved. Furthermore, since the light emitting layer is provided after the first color conversion layer is disposed, it is possible to prevent the material used for the first color conversion layer from entering the light emitting layer.
本発明の実施の形態１に係る発光素子１０の構成を示す断面図である。It is sectional drawing which shows the structure of the light emitting element 10 which concerns on Embodiment 1 of this invention. 本発明の実施の形態２に係る発光素子２０の構成を示す断面図である。It is sectional drawing which shows the structure of the light emitting element 20 which concerns on Embodiment 2 of this invention. 本発明の実施例１に係る発光素子におけるカラーフィルタの厚さと光取出し効率との関係を示す図である。It is a figure which shows the relationship between the thickness of the color filter in the light emitting element which concerns on Example 1 of this invention, and light extraction efficiency. 本発明の実施例１に係る発光素子におけるカラーフィルタの厚さと視野角依存性との関係を示す図である。It is a figure which shows the relationship between the thickness of the color filter and viewing angle dependence in the light emitting element which concerns on Example 1 of this invention. 本発明の実施の形態３に係る発光素子３０の構成を示す断面図である。It is sectional drawing which shows the structure of the light emitting element 30 which concerns on Embodiment 3 of this invention. 本発明の実施の形態４に係る発光素子４０の構成を示す断面図である。It is sectional drawing which shows the structure of the light emitting element 40 which concerns on Embodiment 4 of this invention. 本発明の実施の形態５に係る発光素子５０の構成を示す断面図である。It is sectional drawing which shows the structure of the light emitting element 50 which concerns on Embodiment 5 of this invention. 本発明の実施の形態６に係る発光素子６０の構成を示す断面図である。It is sectional drawing which shows the structure of the light emitting element 60 which concerns on Embodiment 6 of this invention. 従来の形態に係る有機ＥＬ素子の構成を示す断面図である。It is sectional drawing which shows the structure of the organic EL element which concerns on the conventional form.
符号の説明Explanation of symbols
１０、２０、３０、４０、５０、６０　発光素子
１１　基板
１２　光反射層
１３、１３Ｂ、１３Ｇ、１３Ｒ　第１の色変換層
１４　第１の電極
１５、１５Ｂ、１５Ｇ、１５Ｒ　発光層
１６　第２の電極
１７Ｂ、１７Ｇ、１７Ｒ　第２の色変換層
５０　有機ＥＬ素子
５１　基板
５２　光反射層
５３　色変換層
５４　第１の電極
５５　有機ＥＬ層
５６　第２の電極 10, 20, 30, 40, 50, 60 Light-emitting element 11 Substrate 12 Light reflection layer 13, 13B, 13G, 13R First color conversion layer 14 First electrode 15, 15B, 15G, 15R Light-emitting layer 16 Second Electrodes 17B, 17G, and 17R Second color conversion layer 50 Organic EL element 51 Substrate 52 Light reflection layer 53 Color conversion layer 54 First electrode 55 Organic EL layer 56 Second electrode
　以下、本発明の実施の形態に係る発光素子について、添付図面を参照しながら説明する。なお、図面において、実質的に同一の部材には同一の符号を付している。 Hereinafter, light-emitting elements according to embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, substantially the same members are denoted by the same reference numerals.
（実施の形態１）
　図１は、本発明の実施の形態１に係る発光素子１０の構成を示す断面図である。この発光素子１０は、基板１１の上に、光反射層１２が形成されている。光反射層１２の上には、第１の色変換層１３が形成されている。また、第１の色変換層１３の上には、第１の電極１４が形成されている。また、第１の電極１４の上には有機ＥＬ層を含む多層構造を有する発光層１５が形成されている。発光層１５は、第１の電極１４側から順に、電子輸送層、有機ＥＬ層、正孔輸送層が順次積層されて構成されている（図示せず）。発光層１５の上には、第２の電極１６が備えられている。この発光素子１０は、第１の色変換層１３とは逆側の第２の電極１６の側から光を取り出すトップエミッション型である。 (Embodiment 1)
FIG. 1 is a cross-sectional view illustrating a configuration of a light-emitting element 10 according to Embodiment 1 of the present invention. In the light emitting element 10, a light reflecting layer 12 is formed on a substrate 11. A first color conversion layer 13 is formed on the light reflection layer 12. A first electrode 14 is formed on the first color conversion layer 13. A light emitting layer 15 having a multilayer structure including an organic EL layer is formed on the first electrode 14. The light emitting layer 15 is configured by sequentially laminating an electron transport layer, an organic EL layer, and a hole transport layer in order from the first electrode 14 side (not shown). A second electrode 16 is provided on the light emitting layer 15. The light emitting element 10 is a top emission type that extracts light from the second electrode 16 side opposite to the first color conversion layer 13.
　この発光素子１０では、発光層１５からみて光取り出し側ではなく、光反射層１２側に第１の色変換層１３を設けていることを特徴とする。発光層１５から発光した光のうち下方へ出射した光は、第１の色変換層１３で色変換され、光反射層１２で反射されて、第１の色変換層１３、第１の電極１４、発光層１５、第２の電極１６を透過して上部に出射する。発光層１５から上方へ出射した光の一部はそのまま第２の電極１６を透過して上部へ出射し、発光層１５から上方へ出射した光の他の一部は下方に反射され、第１の色変換層１３で色変換され、光反射層１２で反射されて、第２の電極１６を透過して上部に出射する。この発光素子１０によれば、発光層１５から発光した光は第１の色変換層１３でその一部について色変換を受け、光反射層１２で反射した光が第１の色変換層１３を再度通過する。そのため、第１の色変換層１３を光が２回通過するので色変換効率を向上させることができる。また、光反射層１２と第１の電極１４の間に第１の色変換層１３を配置することで、発光層１５から取り出される光の取り出し効率の低下を抑えることができる。また、第１の色変換層１３に用いた材料の発光層１５への侵入を阻止することができる。 This light emitting element 10 is characterized in that the first color conversion layer 13 is provided on the light reflecting layer 12 side, not on the light extraction side as viewed from the light emitting layer 15. Of the light emitted from the light emitting layer 15, the light emitted downward is color-converted by the first color conversion layer 13, reflected by the light reflection layer 12, the first color conversion layer 13, and the first electrode 14. The light-emitting layer 15 and the second electrode 16 are transmitted through and emitted upward. A part of the light emitted upward from the light emitting layer 15 passes through the second electrode 16 as it is and is emitted upward, and another part of the light emitted upward from the light emitting layer 15 is reflected downward, so that the first The color conversion layer 13 performs color conversion, is reflected by the light reflection layer 12, passes through the second electrode 16, and exits upward. According to the light emitting element 10, the light emitted from the light emitting layer 15 undergoes color conversion for a part thereof by the first color conversion layer 13, and the light reflected by the light reflecting layer 12 passes through the first color conversion layer 13. Pass again. Therefore, since light passes through the first color conversion layer 13 twice, color conversion efficiency can be improved. In addition, by disposing the first color conversion layer 13 between the light reflection layer 12 and the first electrode 14, it is possible to suppress a decrease in extraction efficiency of light extracted from the light emitting layer 15. In addition, the material used for the first color conversion layer 13 can be prevented from entering the light emitting layer 15.
　なお、図９に示すように、従来の発光素子５０では、色変換層５３によって不要な波長領域の成分を吸収するということが目的であるため、光取り出し側に色変換層５３が設けられていた。そのため、本願の実施の形態１に係る発光素子１０のように光反射層１２側に第１の色変換層１３を備えるという配置は全く知られておらず、また、光取り出し側とは逆側に色変換層を配置することなど従来全く考えられていなかった。 As shown in FIG. 9, in the conventional light emitting device 50, the color conversion layer 53 is provided with an object to absorb unnecessary wavelength region components, and therefore the color conversion layer 53 is provided on the light extraction side. It was. Therefore, there is no known arrangement in which the first color conversion layer 13 is provided on the light reflecting layer 12 side like the light emitting element 10 according to Embodiment 1 of the present application, and the opposite side to the light extraction side. Conventionally, it has not been considered at all to arrange a color conversion layer.
　また、第２の電極１６は、発光層１５から発光する光については半透明であって、第１の色変換層１３で色変換された光について透明であることが好ましい。第２の電極１６が第１の色変換層１３で色変換された光を選択的に透過させることで取り出す光の波長選択性を改善できる。 The second electrode 16 is preferably translucent for light emitted from the light emitting layer 15 and transparent for light color-converted by the first color conversion layer 13. The wavelength selectivity of the extracted light can be improved by allowing the second electrode 16 to selectively transmit the light whose color has been converted by the first color conversion layer 13.
　以下に、この発光素子１０を構成する各構成部材について説明する。
＜基板＞
　基板１１には、ソーダガラス、無蛍光ガラス、燐酸系ガラス、硼酸系ガラスなどのガラス板、石英、アクリル系樹脂、スチレン系樹脂、ポリカーボネート系樹脂、エポキシ系樹脂、ポリエチレン、ポリエステル、シリコーン系樹脂などのプラスチック板およびプラスチックフィルム、アルミナなどの金属板および金属ホイル等を用いることができる。
　なお、実施の形態２に示すように基板１１側から光を取り出すいわゆるボトムエミッションの場合には、基板１１はガラス基板等のように透明基板であることが必要とされる。 Below, each structural member which comprises this light emitting element 10 is demonstrated.
<Board>
For the substrate 11, glass plates such as soda glass, non-fluorescent glass, phosphoric acid glass, boric acid glass, quartz, acrylic resin, styrene resin, polycarbonate resin, epoxy resin, polyethylene, polyester, silicone resin, etc. A plastic plate and a plastic film, a metal plate such as alumina, and a metal foil can be used.
In the case of so-called bottom emission in which light is extracted from the substrate 11 side as shown in the second embodiment, the substrate 11 is required to be a transparent substrate such as a glass substrate.
＜光反射層＞
　光反射層１２は、マグネシウムや銀、あるいはそれらの合金等で構成されている。光反射層１２は、アルミニウム、マグネシウム、金、銀、銅、クロム、ニッケル、パラジウム、ネオジウム、モリブデンおよびこれらの１種類以上を含む合金の群から選ばれてもよい。この光反射層１２は、膜厚が５～５０ｎｍであることが好ましい。 <Light reflection layer>
The light reflecting layer 12 is made of magnesium, silver, or an alloy thereof. The light reflecting layer 12 may be selected from the group of aluminum, magnesium, gold, silver, copper, chromium, nickel, palladium, neodymium, molybdenum and alloys containing one or more of these. The light reflecting layer 12 preferably has a thickness of 5 to 50 nm.
＜光変換層＞
　第１の色変換層１３は、発光層１５で発光した光の一部を透過させ、一部を吸収し、吸収した波長（色）とは異なる波長（色）の光を放出する機能を有する。この第１の色変換層１３としては、着色透明フィルタ、ダイクロイックミラー、バンドパスフィルタなどを用いることができる。また、第１の色変換層１３の構成材料の例としては、有機顔料、粒子添加有機顔料、金属酸化物、その金属酸化物を含有した樹脂、無機または有機の蛍光色素などを用いることができる。 <Light conversion layer>
The first color conversion layer 13 has a function of transmitting part of the light emitted from the light emitting layer 15, absorbing part of the light, and emitting light having a wavelength (color) different from the absorbed wavelength (color). . As the first color conversion layer 13, a colored transparent filter, a dichroic mirror, a band pass filter, or the like can be used. Examples of the constituent material of the first color conversion layer 13 include organic pigments, particle-added organic pigments, metal oxides, resins containing the metal oxides, inorganic or organic fluorescent dyes, and the like. .
＜第１の電極＞
　第１の電極１４は、発光層１５で発生した光に対して十分な透光性を有する導電性材料により構成されている。また、第１の電極１４は、発光層１５から発光する光、及び、第１の色変換層１３で色変換された光のそれぞれについて透明であることが好ましい。第１の電極１４を構成する材料としては、酸化インジウムスズ（Indium Tin Oxide：ＩＴＯ）や酸化インジウム亜鉛（Indium Zinc Oxide：ＩＺＯ）などが好ましい。室温で成膜しても良好な導電性を得ることができるからである。 <First electrode>
The first electrode 14 is made of a conductive material having sufficient translucency with respect to the light generated in the light emitting layer 15. The first electrode 14 is preferably transparent for each of the light emitted from the light emitting layer 15 and the light color-converted by the first color conversion layer 13. As a material constituting the first electrode 14, indium tin oxide (ITO), indium zinc oxide (IZO), or the like is preferable. This is because good conductivity can be obtained even if the film is formed at room temperature.
＜発光層＞
　発光層１５としては、一層の場合に限られず多層構造であってもよい。また、発光層は、有機発光体を含む有機ＥＬ層を含んでもよい。さらに、有機ＥＬ層を挟持する電子輸送層と正孔輸送層をさらに含んでもよい。またさらに、電子注入層、及び／又は、正孔注入層を備えてもよい。電子注入層及び正孔注入層は、蒸着法、スピンコート法、キャスト法などにより形成できる。 <Light emitting layer>
The light emitting layer 15 is not limited to a single layer and may have a multilayer structure. The light emitting layer may include an organic EL layer containing an organic light emitter. Furthermore, an electron transport layer and a hole transport layer that sandwich the organic EL layer may be further included. Furthermore, an electron injection layer and / or a hole injection layer may be provided. The electron injection layer and the hole injection layer can be formed by vapor deposition, spin coating, casting, or the like.
　＜電子輸送層＞
　電子輸送能を有する電子輸送層の具体例としては、特開平５－１６３４８８号公報のニトロ置換フルオレノン誘導体、チオピランジオキサイド誘導体、ジフェキノン誘導体、ペリレンテトラカルボキシル誘導体、アントラキノジメタン誘導体、フレオレニリデンメタン誘導体、アントロン誘導体、オキサジアゾール誘導体、ペリノン誘導体、キノリン錯体誘導体などの化合物を使用することができる。 <Electron transport layer>
Specific examples of the electron transporting layer having electron transporting ability include nitro-substituted fluorenone derivatives, thiopyrandioxide derivatives, diphequinone derivatives, perylene tetracarboxyl derivatives, anthraquinodimethane derivatives, fluorenylidenes described in JP-A-5-163488. Compounds such as methane derivatives, anthrone derivatives, oxadiazole derivatives, perinone derivatives, quinoline complex derivatives, and the like can be used.
　＜有機ＥＬ層＞
　有機ＥＬ層の具体例としては、特開平５－１６３４８８号公報に記載のオキシノイド化合物、ペリレン化合物、クマリン化合物、アザクマリン化合物、オキサゾール化合物、オキサジアゾール化合物、ペリノン化合物、ピロロピロール化合物、ナフタレン化合物、アントラセン化合物、フルオレン化合物、フルオランテン化合物、テトラセン化合物、ピレン化合物、コロネン化合物、キノロン化合物及びアザキノロン化合物、ピラゾリン誘導体及びピラゾロン誘導体、ローダミン化合物、クリセン化合物、フェナントレン化合物、シクロペンタジエン化合物、スチルベン化合物、ジフェニルキノン化合物、スチリル化合物、ブタジエン化合物、ジシアノメチレンピラン化合物、ジシアノメチレンチオピラン化合物、フルオレセイン化合物、ピリリウム化合物、チアピリリウム化合物、セレナピリリウム化合物、テルロピリリウム化合物、芳香族アルダジエン化合物、オリゴフェニレン化合物、チオキサンテン化合物、アンスラセン化合物、シアニン化合物、アクリジン化合物、８－ヒドロキシキノリン化合物の金属鎖体、２、２‘－ビピリジン化合物の金属鎖体、シッフ塩とＩＩＩ族金属との鎖体、オキシン金属鎖体、希土類鎖体などの蛍光物質を使用することができる。有機ＥＬ層は蒸着法、スピンコート法、キャスト法などにより形成できる。 <Organic EL layer>
Specific examples of the organic EL layer include oxinoid compounds, perylene compounds, coumarin compounds, azacoumarin compounds, oxazole compounds, oxadiazole compounds, perinone compounds, pyrrolopyrrole compounds, naphthalene compounds, anthracenes described in JP-A-5-163488. Compound, fluorene compound, fluoranthene compound, tetracene compound, pyrene compound, coronene compound, quinolone compound and azaquinolone compound, pyrazoline derivative and pyrazolone derivative, rhodamine compound, chrysene compound, phenanthrene compound, cyclopentadiene compound, stilbene compound, diphenylquinone compound, styryl Compounds, butadiene compounds, dicyanomethylenepyran compounds, dicyanomethylenethiopyran compounds, fluorescein compounds, Lithium compound, thiapyrylium compound, serenapyrylium compound, telluropyrylium compound, aromatic aldadiene compound, oligophenylene compound, thioxanthene compound, anthracene compound, cyanine compound, acridine compound, 8-hydroxyquinoline compound metal chain, 2, 2 ′ -Fluorescent materials such as metal chains of bipyridine compounds, chains of Schiff salts and Group III metals, oxine metal chains, and rare earth chains can be used. The organic EL layer can be formed by vapor deposition, spin coating, casting, or the like.
　＜正孔輸送層＞
　正孔輸送層の具体例としては、特開平５－１６３４８８号公報に記載のトリアゾール誘導体、オキサジアゾール誘導体、イミダゾール誘導体、ポリアリールアルカン誘導体、ピラゾリン誘導体及びピラゾロン誘導体、フェニレンジアミン誘導体、アリールアミン誘導体、アミノ置換カルコン誘導体、オキサゾール誘導体、スチリルアントラセン誘導体、フルオレノン誘導体、ヒドラゾン誘導体、スチルベン誘導体、ポリフィリン化合物、芳香族第三級アミン化合物及びスチリルアミン化合物、ブタジエン化合物、ポリスチレン誘導体、ヒドラゾン誘導体、トリフェニルメタン誘導体、テトラフェニルベンジン誘導体などを使用することができるが、特に好ましくは、ポリフィリン化合物、芳香族第三級アミン化合物及びスチリルアミン化合物である。 <Hole transport layer>
Specific examples of the hole transport layer include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives described in JP-A-5-163488. Amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, porphyrin compounds, aromatic tertiary amine compounds and styrylamine compounds, butadiene compounds, polystyrene derivatives, hydrazone derivatives, triphenylmethane derivatives, Tetraphenylbenzine derivatives and the like can be used, but particularly preferably, porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds A.
＜第２の電極＞
　第２の電極１６は、発光層１５で発生した光に対して、特定の波長の光のみを透過する導電性材料により構成されていることが好ましい。また、発光層１５から発光した光について半透明であって、第１の色変換層１３で色変換された光について透明であってもよい。第２の電極１６が第１の色変換層１３で色変換された光を選択的に透過させることで、第２の電極１６から取り出す光における波長選択性を改善できる。第２の電極１６を構成する材料としては、酸化インジウムスズ（Indium Tin Oxide：ＩＴＯ）や酸化インジウム亜鉛（Indium Zinc Oxide：ＩＺＯ）などが好ましい。室温で成膜しても良好な導電性を得ることができるからである。 <Second electrode>
The second electrode 16 is preferably made of a conductive material that transmits only light of a specific wavelength with respect to the light generated in the light emitting layer 15. Further, the light emitted from the light emitting layer 15 may be translucent, and the light subjected to color conversion by the first color conversion layer 13 may be transparent. By allowing the second electrode 16 to selectively transmit the light whose color has been converted by the first color conversion layer 13, the wavelength selectivity of the light extracted from the second electrode 16 can be improved. As a material constituting the second electrode 16, indium tin oxide (ITO), indium zinc oxide (IZO), or the like is preferable. This is because good conductivity can be obtained even if the film is formed at room temperature.
（実施の形態２）
　図２は、本発明の実施の形態２に係る発光素子２０の構成を示す断面図である。この発光素子２０は、実施の形態１に係る発光素子と比較すると、光取り出し方向が逆方向で、底部の基板１１側から発光を取り出すボトムエミッション型である。これに伴って、この発光素子２０では、光反射層１２と、第１の色変換層１３とを上部に設けるように配置を変更している点で相違する。なお、この場合には、底部の基板１１の側から光を取り出すので、基板１１は透明基板であることが必要である。 (Embodiment 2)
FIG. 2 is a cross-sectional view showing the configuration of the light-emitting element 20 according to Embodiment 2 of the present invention. The light emitting element 20 is a bottom emission type in which the light extraction direction is opposite to that of the light emitting element according to Embodiment 1, and the light emission is extracted from the bottom substrate 11 side. Accordingly, the light emitting element 20 is different in that the arrangement is changed so that the light reflecting layer 12 and the first color conversion layer 13 are provided on the upper portion. In this case, since light is extracted from the bottom substrate 11 side, the substrate 11 needs to be a transparent substrate.
（実施例１）
　本発明の実施例１に係る有機ＥＬ素子１０について、以下の条件により光学的シミュレーションを行った。
　この有機ＥＬ素子を構成する各構成部材として、光反射層としてＡｇＰｄＣｕ合金（略称：ＡＰＣ）を用いた。その上に緑色の波長のみを透過（４８０ｎｍ～５８０ｎｍの波長の光を８５％以上透過）するカラーフィルタとして５０～１８０ｎｍ、ＩＴＯを１２０ｎｍ、電子注入層を２０ｎｍ、発光層を８０ｎｍ、正孔注入層を厚さ１００ｎｍ、ＩＴＯを厚さ１２０ｎｍで順次積層した。 Example 1
About the organic EL element 10 which concerns on Example 1 of this invention, the optical simulation was performed on condition of the following.
As each constituent member constituting this organic EL element, an AgPdCu alloy (abbreviation: APC) was used as a light reflection layer. On top of that, 50 to 180 nm as a color filter that transmits only the green wavelength (transmits light of 480 nm to 580 nm wavelength more than 85%), 120 nm of ITO, 20 nm of electron injection layer, 80 nm of light emitting layer, hole injection layer Were stacked sequentially with a thickness of 100 nm and ITO with a thickness of 120 nm.
　図３、図４には、発光層からの発光に関する光学的シミュレーション結果を示す。図３は、第１の色変換層としてカラーフィルタ（ＣＦ）の厚さに対する光取り出し効率との関係を示すグラフである。図４は、観察角度６５度と８５度のそれぞれの場合について、カラーフィルタ（ＣＦ）の厚さに対する角度色差（Δｕｖ）の関係を示すグラフである。図３によれば、カラーフィルタを光反射層の上に１１０ｎｍ備えることにより、光取出し効率が向上することが確認された。また、図４によれば、正面から斜め方向に向けて視野角がずれることによって、座標上における角度色差（Δｕｖ）の変化が非常に小さくなった。 3 and 4 show the optical simulation results regarding the light emission from the light emitting layer. FIG. 3 is a graph showing the relationship between the light extraction efficiency and the thickness of the color filter (CF) as the first color conversion layer. FIG. 4 is a graph showing the relationship of the angle color difference (Δuv) with respect to the thickness of the color filter (CF) for each of the observation angles of 65 degrees and 85 degrees. According to FIG. 3, it was confirmed that the light extraction efficiency is improved by providing a color filter with a thickness of 110 nm on the light reflection layer. Further, according to FIG. 4, the change in the angular color difference (Δuv) on the coordinates is very small due to the deviation of the viewing angle from the front toward the oblique direction.
　従来の色変換層を備えた表示装置では、角度色差（Δｕｖ）が大きくなると、観察角度に応じて色温度が変化していた。また、この色温度の変化は観察者の主観によるところも大きかった。一般に角度色差（Δｕｖ）が小さくなれば、観察角度による色温度変化も小さくなり、観察者の主観を考慮しても観察角度に応じた色温度変化を感じる観察者の割合は減少した。実際に、観察者の主観によって色温度変化の感じ方が異なるのは、角度色差（Δｕｖ）が０．０１～０．０２の範囲であり、このような角度色差（Δｕｖ）では、観察者の主観によって、観察角度に依存して色温度が変化して感じる観察者と、色温度の変化を感じない観察者との割合が混在するようになるが、各色温度において、０．０１５前後で角度色差が気になることが多い。 In a display device having a conventional color conversion layer, when the angular color difference (Δuv) increases, the color temperature changes according to the observation angle. In addition, this change in color temperature was largely due to the subjectivity of the observer. In general, when the angle color difference (Δuv) is reduced, the color temperature change due to the observation angle is also reduced, and the percentage of observers who feel the color temperature change according to the observation angle is reduced even when the subjectivity of the observer is taken into consideration. Actually, it is the angle color difference (Δuv) in the range of 0.01 to 0.02 that the color temperature change perceives differently depending on the subjectivity of the observer. With such an angle color difference (Δuv), Depending on the subjectivity, the ratio of an observer who feels that the color temperature changes depending on the observation angle and an observer who does not feel the change of the color temperature are mixed, but at each color temperature, the angle is around 0.015 Often color differences are a concern.
　なお、上記観察角度とは、発光層１５の表面の中心を通り、かつ発光層１５の表面に垂直な線を軸線（０度）として、観察点と発光層１５の表面の中心とを結ぶ線と軸線とのなす角度Ｘをいうものとする。なお、図１では光取り出し側の第２の電極１６の表面で角度Ｘを示しているが、観察点までの距離に比べて膜厚が薄いことを考慮すれば両者は実質的に同様の角度とみなすことができる。また、観察角度Ｘ度における角度色差（Δｕｖ）とは、次式により求めることができる。 The observation angle is a line connecting the observation point and the center of the surface of the light-emitting layer 15 with a line passing through the center of the surface of the light-emitting layer 15 and perpendicular to the surface of the light-emitting layer 15 as an axis (0 degree). And the angle X formed by the axis. In FIG. 1, the angle X is shown on the surface of the second electrode 16 on the light extraction side. However, considering that the film thickness is smaller than the distance to the observation point, they are substantially the same angle. Can be considered. Further, the angle color difference (Δuv) at the observation angle X degrees can be obtained by the following equation.
［数１］
Δｕｖ＝｛（ｕＸ－ｕ０）２＋（ｖＸ－ｖ０）２｝１／２
　ここで、ｕＸ，ｖＸは観察角度Ｘ度において、波長３８０～７８０ｎｍの発光スペクトルを測定したときのｕ値，ｖ値である。また、ｕ０，ｖ０は観察角度０度において、波長３８０～７８０ｎｍの発光スペクトルを測定したときのｕ値，ｖ値である。 [Equation 1]
Δuv = {(uX−u0) 2 + (vX−v0) 2 } 1/2
Here, uX and vX are u value and v value when an emission spectrum with a wavelength of 380 to 780 nm is measured at an observation angle of X degrees. U0 and v0 are the u value and the v value when the emission spectrum with a wavelength of 380 to 780 nm is measured at an observation angle of 0 degree.
（実施の形態３）
　図５は、本発明の実施の形態３に係る発光素子３０の構成を示す断面図である。この発光素子３０は、実施の形態１に係る発光素子１０と比較すると、１ピクセルがＲ、Ｇ、Ｂを発光色とする複数のサブピクセル（画素）からなる点で相違する。各サブピクセルでは、基板１１の上に、光反射層１２が形成されている。光反射層１２の上には、画素ごとに第１の色変換層１３Ｂ、１３Ｇ、１３Ｒが形成されている。また、第１の色変換層１３Ｂ、１３Ｇ、１３Ｒの上には、第１の電極１４が形成されている。なお、第１の色変換層１３Ｂ、１３Ｇ、１３Ｒは、画素毎に同一の厚みとしてもよい。また、第１の電極１４の上には有機ＥＬ層を含む多層構造を有する発光層１５Ｂ、１５Ｇ、１５Ｒが形成されている。発光層１５Ｂ、１５Ｇ、１５Ｒは、一例として第１の電極１４側から順に、電子輸送層、有機ＥＬ層、正孔輸送層が順次積層されて構成されている（図示せず）。発光層１５Ｂ、１５Ｇ、１５Ｒの上には、第２の電極１６が備えられている。この発光素子３０は第１の色変換層１３とは逆側の第２の電極１６の側から光を取り出すトップエミッション型である。 (Embodiment 3)
FIG. 5 is a cross-sectional view showing the configuration of the light emitting element 30 according to Embodiment 3 of the present invention. The light emitting element 30 is different from the light emitting element 10 according to the first embodiment in that one pixel includes a plurality of subpixels (pixels) having R, G, and B as emission colors. In each subpixel, a light reflecting layer 12 is formed on the substrate 11. On the light reflection layer 12, first color conversion layers 13B, 13G, and 13R are formed for each pixel. A first electrode 14 is formed on the first color conversion layers 13B, 13G, and 13R. Note that the first color conversion layers 13B, 13G, and 13R may have the same thickness for each pixel. In addition, light emitting layers 15B, 15G, and 15R having a multilayer structure including an organic EL layer are formed on the first electrode. As an example, the light emitting layers 15B, 15G, and 15R are configured by sequentially laminating an electron transport layer, an organic EL layer, and a hole transport layer from the first electrode 14 side (not shown). A second electrode 16 is provided on the light emitting layers 15B, 15G, and 15R. The light emitting element 30 is a top emission type in which light is extracted from the second electrode 16 side opposite to the first color conversion layer 13.
　積層構造の厚みは各サブピクセルとも等しく設定されている。また、全サブピクセル上に光拡散フィルムを用いることにより、有機ＥＬ表示装置の視野角を十分に拡大し、視角変化によるコントラスト低下、及び色相変化等がほとんど発生することのない有機ＥＬ発光素子およびそれを用いた有機ＥＬ表示装置を提供することができる（図示せず）。 The thickness of the laminated structure is set equal for each subpixel. In addition, by using a light diffusion film on all the subpixels, the viewing angle of the organic EL display device is sufficiently expanded, and the organic EL light-emitting element that hardly causes a decrease in contrast due to a change in viewing angle, a hue change, and the like An organic EL display device using the same can be provided (not shown).
　この発光素子３０では、発光層１５Ｂ、１５Ｇ、１５Ｒから光取り出し側ではなく、光反射層１２側に第１の色変換層１３Ｂ、１３Ｇ、１３Ｒを設けていることを特徴とする。発光層１５Ｂ、１５Ｇ、１５Ｒから発光した光のうち下方へ出射した光は第１の色変換層１３で色変換され、光反射層１２で反射されて、第１の色変換層１３Ｂ、１３Ｇ、１３Ｒ、第１の電極１４、発光層１５Ｂ、１５Ｇ、１５Ｒ、第２の電極１６を透過して上部に出射する。発光層１５Ｂ、１５Ｇ、１５Ｒから上方へ出射した光の一部はそのまま第２の電極１６を透過して上部へ出射し、一部は下方に反射され、第１の色変換層１３Ｂ、１３Ｇ、１３Ｒで色変換され、光反射層１２で反射されて、第２の電極１６を透過して上部に出射する。 This light emitting element 30 is characterized in that the first color conversion layers 13B, 13G, and 13R are provided not on the light extraction side from the light emitting layers 15B, 15G, and 15R but on the light reflection layer 12 side. Of the light emitted from the light emitting layers 15B, 15G, and 15R, the light emitted downward is color-converted by the first color conversion layer 13, reflected by the light reflection layer 12, and the first color conversion layers 13B, 13G, 13R, the first electrode 14, the light emitting layers 15B, 15G, 15R, and the second electrode 16 are transmitted and emitted upward. A part of the light emitted upward from the light emitting layers 15B, 15G, and 15R passes through the second electrode 16 as it is and is emitted upward, and part of the light is reflected downward, and the first color conversion layers 13B, 13G, The color is converted by 13R, is reflected by the light reflecting layer 12, passes through the second electrode 16, and is emitted upward.
　この発光素子３０によれば、発光層１５Ｂ、１５Ｇ、１５Ｒから発光した光は第１の色変換層１３Ｂ、１３Ｇ、１３Ｒでその一部について色変換を受け、光反射層１２で反射した光が第１の色変換層１３Ｂ、１３Ｇ、１３Ｒを再度通過する。そのため、第１の色変換層１３Ｂ、１３Ｇ、１３Ｒを光が２回通過するので色変換効率を向上させることができる。また、光反射層１２と第１の電極１４の間に第１の色変換層１３Ｂ、１３Ｇ、１３Ｒを配置することで、発光層１５Ｂ、１５Ｇ、１５Ｒから取り出される光の取り出し効率の低下を抑えることができる。また、第１の色変換層１３Ｂ、１３Ｇ、１３Ｒに用いた材料の発光層１５Ｂ、１５Ｇ、１５Ｒへの侵入を阻止することができる。 According to the light emitting element 30, the light emitted from the light emitting layers 15B, 15G, and 15R undergoes color conversion for some of the first color conversion layers 13B, 13G, and 13R, and the light reflected by the light reflecting layer 12 is reflected. It passes through the first color conversion layers 13B, 13G, and 13R again. Therefore, since light passes through the first color conversion layers 13B, 13G, and 13R twice, color conversion efficiency can be improved. Further, by disposing the first color conversion layers 13B, 13G, and 13R between the light reflecting layer 12 and the first electrode 14, it is possible to suppress a decrease in extraction efficiency of light extracted from the light emitting layers 15B, 15G, and 15R. be able to. In addition, the material used for the first color conversion layers 13B, 13G, and 13R can be prevented from entering the light-emitting layers 15B, 15G, and 15R.
（実施の形態４）
　図６は、本発明の実施の形態４に係る発光素子４０の構成を示す断面図である。この発光素子４０は、実施の形態３に係る発光素子３０と比較すると、第１の色変換層１３が複数の画素（青色、緑色、赤色）にわたって共通に構成されている点で相違する。したがって、本実施の形態では、複数の画素にわたって、第１の色変換層１３は、同一の材料からなる。この場合、複数の画素（青色、緑色、赤色）にわたって共通となる第１の色変換層１３は、それぞれの画素から取り出す青色、緑色、赤色の各波長帯域について選択透過性を有する材料、例えば、３波長フィルタ等を用いることが好ましい。なお、第１の色変換層１３は、各画素にわたって連続していればよく、図６に示すように画素間には凹凸を有していてもよい。また、第１の色変換層１３は、画素ごとに異なる厚さ、又は、同一の厚さであってもよい。さらに、第１の色変換層１３は、複数の画素にわたって全体として面一となっていてもよい。 (Embodiment 4)
FIG. 6 is a cross-sectional view showing the configuration of the light emitting element 40 according to Embodiment 4 of the present invention. The light emitting element 40 is different from the light emitting element 30 according to Embodiment 3 in that the first color conversion layer 13 is configured in common over a plurality of pixels (blue, green, red). Therefore, in the present embodiment, the first color conversion layer 13 is made of the same material over a plurality of pixels. In this case, the first color conversion layer 13 that is common to a plurality of pixels (blue, green, red) is a material having selective transparency for each wavelength band of blue, green, red extracted from each pixel, for example, It is preferable to use a three-wavelength filter or the like. The first color conversion layer 13 only needs to be continuous over each pixel, and may have irregularities between the pixels as shown in FIG. Further, the first color conversion layer 13 may have a different thickness for each pixel or the same thickness. Further, the first color conversion layer 13 may be flush with the entire pixel.
　このように第１の色変換層１３を複数の画素にわたって共通に構成することで製造プロセスを簡素化できる。 As described above, the first color conversion layer 13 is configured in common over a plurality of pixels, whereby the manufacturing process can be simplified.
（実施の形態５）
　図７は、本発明の実施の形態５に係る発光素子５０の構成を示す断面図である。この発光素子５０は、実施の形態３に係る発光素子３０と比較すると、第２の電極１６の上に、画素毎に分離して構成された第２の色変換層１７Ｂ、１７Ｇ、１７Ｒを設けた点で相違する。各サブピクセルでは、基板１１の上に、光反射層１２が形成されている。光反射層１２の上には、画素ごとに第１の色変換層１３Ｂ、１３Ｇ、１３Ｒが形成されている。また、第１の色変換層１３Ｂ、１３Ｇ、１３Ｒの上には、第１の電極１４が形成されている。また、第１の電極１４の上には有機ＥＬ層を含む多層構造を有する発光層１５Ｂ、１５Ｇ、１５Ｒが形成されている。発光層１５Ｂ、１５Ｇ、１５Ｒは、第１の電極１４側から順に、電子輸送層、有機ＥＬ層、正孔輸送層が順次積層されて構成されている（図示せず）。発光層１５Ｂ、１５Ｇ、１５Ｒの上には、第２の電極１６が備えられている。さらに、第２の電極１６の上に画素毎に設けられた第２の色変換層１７Ｂ、１７Ｇ、１７Ｒを備える。この発光素子５０は、第１の色変換層１３Ｂ、１３Ｇ、１３Ｒとは逆側の第２の電極１６の側から光を取り出すトップエミッション型である。 (Embodiment 5)
FIG. 7 is a cross-sectional view showing a configuration of the light emitting element 50 according to Embodiment 5 of the present invention. Compared with the light-emitting element 30 according to the third embodiment, the light-emitting element 50 is provided with second color conversion layers 17B, 17G, and 17R that are configured separately for each pixel on the second electrode 16. It is different in point. In each subpixel, a light reflecting layer 12 is formed on the substrate 11. On the light reflection layer 12, first color conversion layers 13B, 13G, and 13R are formed for each pixel. A first electrode 14 is formed on the first color conversion layers 13B, 13G, and 13R. In addition, light emitting layers 15B, 15G, and 15R having a multilayer structure including an organic EL layer are formed on the first electrode. The light emitting layers 15B, 15G, and 15R are configured by sequentially laminating an electron transport layer, an organic EL layer, and a hole transport layer in this order from the first electrode 14 side (not shown). A second electrode 16 is provided on the light emitting layers 15B, 15G, and 15R. Furthermore, second color conversion layers 17B, 17G, and 17R provided for each pixel on the second electrode 16 are provided. The light emitting element 50 is a top emission type in which light is extracted from the second electrode 16 side opposite to the first color conversion layers 13B, 13G, and 13R.
　この発光素子５０では、発光層１５Ｂ、１５Ｇ、１５Ｒから見て光取り出し側に第２の色変換層１７Ｂ、１７Ｇ、１７Ｒを設けているだけではなく、光反射層１２側に第１の色変換層１３Ｂ、１３Ｇ、１３Ｒを設けていることを特徴とする。発光層１５Ｂ、１５Ｇ、１５Ｒから発光した光のうち下方へ出射した光は第１の色変換層１３Ｂ、１３Ｇ、１３Ｒで色変換され、光反射層１２で反射されて、第１の色変換層１３Ｂ、１３Ｇ、１３Ｒ、第１の電極１４、発光層１５Ｂ、１５Ｇ、１５Ｒ、第２の電極１６、第２の色変換層１７Ｂ、１７Ｇ、１７Ｒを透過して上部に出射する。発光層１５から上方へ出射した光の一部は第２の電極１６、第２の色変換層１７Ｂ、１７Ｇ、１７Ｒを透過して上部へ出射し、発光層１５Ｂ、１５Ｇ、１５Ｒから上方へ出射した光の他の一部は下方に反射され、第１の色変換層１３Ｂ、１３Ｇ、１３Ｒで色変換され、光反射層１２で反射されて、第２の電極１６、第２の色変換層１７Ｂ、１７Ｇ、１７Ｒを透過して上部に出射する。 In the light emitting element 50, not only the second color conversion layers 17B, 17G, and 17R are provided on the light extraction side when viewed from the light emitting layers 15B, 15G, and 15R, but also the first color conversion on the light reflection layer 12 side. Layers 13B, 13G, and 13R are provided. Of the light emitted from the light emitting layers 15B, 15G, and 15R, the light emitted downward is color-converted by the first color conversion layers 13B, 13G, and 13R, reflected by the light reflecting layer 12, and then the first color conversion layer. The light passes through 13B, 13G, and 13R, the first electrode 14, the light emitting layers 15B, 15G, and 15R, the second electrode 16, and the second color conversion layers 17B, 17G, and 17R, and is emitted upward. A part of the light emitted upward from the light emitting layer 15 is transmitted through the second electrode 16 and the second color conversion layers 17B, 17G, and 17R to be emitted upward, and emitted upward from the light emitting layers 15B, 15G, and 15R. The other part of the reflected light is reflected downward, color-converted by the first color conversion layers 13B, 13G, and 13R, reflected by the light reflection layer 12, and the second electrode 16 and the second color conversion layer. The light passes through 17B, 17G, and 17R and is emitted upward.
　この発光素子５０によれば、発光層１５Ｂ、１５Ｇ、１５Ｒから発光した光は、第１の色変換層１３Ｂ、１３Ｇ、１３Ｒでその一部について色変換を受け、光反射層１２で反射した光が第１の色変換層１３Ｂ、１３Ｇ、１３Ｒを再度通過する。そして、多層構造の発光層１５Ｂ、１５Ｇ、１５Ｒ中を通過した反射光および発光層１５Ｂ、１５Ｇ、１５Ｒから第２の電極１６の方向に出射した光が第２の色変換層１７Ｂ、１７Ｇ、１７Ｒを透過して上部に出射するため、さらに色変換効率を向上させることができる。また、光反射層１２と第１の電極１４の間に第１の色変換層１３Ｂ、１３Ｇ、１３Ｒを配置することで、発光層１５Ｂ、１５Ｇ、１５Ｒから取り出される光の取り出し効率の低下を抑えることができる。また、第１の色変換層１３Ｂ、１３Ｇ、１３Ｒに用いた材料の発光層１５Ｂ、１５Ｇ、１５Ｒへの侵入を阻止することができる。 According to the light emitting element 50, the light emitted from the light emitting layers 15B, 15G, and 15R undergoes color conversion for a part thereof by the first color conversion layers 13B, 13G, and 13R, and is reflected by the light reflecting layer 12. Passes again through the first color conversion layers 13B, 13G, and 13R. The reflected light passing through the multilayer light emitting layers 15B, 15G, and 15R and the light emitted from the light emitting layers 15B, 15G, and 15R toward the second electrode 16 are the second color conversion layers 17B, 17G, and 17R. And the color conversion efficiency can be further improved. Further, by disposing the first color conversion layers 13B, 13G, and 13R between the light reflecting layer 12 and the first electrode 14, it is possible to suppress a decrease in extraction efficiency of light extracted from the light emitting layers 15B, 15G, and 15R. be able to. In addition, the material used for the first color conversion layers 13B, 13G, and 13R can be prevented from entering the light-emitting layers 15B, 15G, and 15R.
（実施の形態６）
　図８は、本発明の実施の形態６に係る発光素子６０の構成を示す断面図である。この発光素子６０は、実施の形態５に係る発光素子５０と比較すると、第１の色変換層１３が複数の画素（青色、緑色、赤色）にわたって共通に構成されている点で相違する。したがって、本実施の形態では、複数の画素にわたって、第１の色変換層１３は、同一の材料からなる。この場合、複数の画素（青色、緑色、赤色）にわたって共通となる第１の色変換層１３は、それぞれの画素から取り出す青色、緑色、赤色の各波長帯域について選択透過性を有する材料、例えば、３波長フィルタ等を用いることが好ましい。なお、第１の色変換層１３は、各画素にわたって連続していればよく、図８に示すように画素間には凹凸を有していてもよい。また、第１の色変換層１３は、画素ごとに異なる厚さ、又は、同一の厚さであってもよい。さらに、第１の色変換層１３は、複数の画素にわたって全体として面一となっていてもよい。 (Embodiment 6)
FIG. 8 is a cross-sectional view showing the configuration of the light emitting element 60 according to Embodiment 6 of the present invention. The light emitting element 60 is different from the light emitting element 50 according to the fifth embodiment in that the first color conversion layer 13 is configured in common over a plurality of pixels (blue, green, red). Therefore, in the present embodiment, the first color conversion layer 13 is made of the same material over a plurality of pixels. In this case, the first color conversion layer 13 that is common to a plurality of pixels (blue, green, red) is a material having selective transparency for each wavelength band of blue, green, red extracted from each pixel, for example, It is preferable to use a three-wavelength filter or the like. The first color conversion layer 13 only needs to be continuous over each pixel, and may have irregularities between the pixels as shown in FIG. Further, the first color conversion layer 13 may have a different thickness for each pixel or the same thickness. Further, the first color conversion layer 13 may be flush with the entire pixel.
　このように第１の色変換層１３を複数の画素にわたって共通に構成することで製造プロセスを簡素化できる。 As described above, the first color conversion layer 13 is configured in common over a plurality of pixels, whereby the manufacturing process can be simplified.
　本発明は、平面光源及びフラットディスプレイなどに用いられる有機ＥＬ表示装置に利用可能である。 The present invention can be used for organic EL display devices used for flat light sources, flat displays, and the like.

Claims (14)

  1. 　光反射層と、
    　前記光反射層の上に設けられた第１の色変換層と、
    　前記色変換層の上に設けられた第１の電極と、
    　前記第１の電極の上に設けられた発光層と、
    　前記発光層の上に設けられた第２の電極と、
    を備え、
    　前記第２の電極から光を取り出すことを特徴とする発光素子。     A light reflecting layer;
    A first color conversion layer provided on the light reflecting layer;
    A first electrode provided on the color conversion layer;
    A light emitting layer provided on the first electrode;
    A second electrode provided on the light emitting layer;
    With
    A light-emitting element that extracts light from the second electrode.
  2. 　前記第２の電極は、前記発光層から発光する光について半透明であって、前記第１の色変換層で色変換された光について透明であることを特徴とする請求項１に記載の発光素子。 2. The light emitting device according to claim 1, wherein the second electrode is translucent with respect to light emitted from the light emitting layer, and is transparent with respect to light subjected to color conversion in the first color conversion layer. element.
  3. 　前記第１の電極は、前記発光層から発光する光、及び、前記第１の色変換層で色変換された光のそれぞれについて透明であることを特徴とする請求項１に記載の発光素子。 The light-emitting element according to claim 1, wherein the first electrode is transparent for each of light emitted from the light-emitting layer and light converted in color by the first color conversion layer.
  4. 　前記光反射層は、アルミニウム、マグネシウム、金、銀、銅、クロム、ニッケル、パラジウム、ネオジウム、モリブデンおよびこれらの１種類以上を含む合金の群から選ばれることを特徴とする請求項１に記載の発光素子。 The said light reflection layer is chosen from the group of the alloy containing aluminum, magnesium, gold | metal | money, silver, copper, chromium, nickel, palladium, neodymium, molybdenum, and one or more types of these. Light emitting element.
  5. 　前記第１の色変換層は、着色フィルタ、ダイクロイックフィルタおよびバンドパスフィルタの群から選ばれることを特徴とする請求項１に記載の発光素子。 The light emitting device according to claim 1, wherein the first color conversion layer is selected from the group of a coloring filter, a dichroic filter, and a band pass filter.
  6. 　前記第１の色変換層は、蛍光色素を含有することを特徴とする請求項１に記載の発光素子。 The light emitting device according to claim 1, wherein the first color conversion layer contains a fluorescent dye.
  7. 　前記発光層は、積層構造を有することを特徴とする請求項１に記載の発光素子。 2. The light emitting device according to claim 1, wherein the light emitting layer has a laminated structure.
  8. 　前記第１の色変換層が画素毎に分離して構成されており、画素毎に同じ膜厚及び同じ材料で構成されていることを特徴とする請求項１に記載の発光素子。 The light emitting device according to claim 1, wherein the first color conversion layer is configured to be separated for each pixel, and is configured to have the same film thickness and the same material for each pixel.
  9. 　前記第１の色変換層が画素毎に分離して構成されており、画素毎に異なる膜厚、又は、異なる材料で構成されていることを特徴とする請求項１に記載の発光素子。 The light emitting device according to claim 1, wherein the first color conversion layer is configured to be separated for each pixel, and is configured of a different film thickness or a different material for each pixel.
  10. 　前記第１の色変換層と前記光反射層の両方が画素毎に分離して構成されており、画素毎にそれぞれ同じ膜厚及び同じ材料で構成されていることを特徴とする請求項１に記載の発光素子。 The first color conversion layer and the light reflection layer are both configured to be separated for each pixel, and each pixel is composed of the same film thickness and the same material. The light emitting element of description.
  11. 　前記第１の色変換層は、複数の画素にわたって共通に構成されていることを特徴とする請求項１に記載の発光素子。 The light emitting device according to claim 1, wherein the first color conversion layer is configured in common over a plurality of pixels.
  12. 　前記第２の電極の上に設けられた第２の色変換層をさらに備え、前記第２の色変換層は画素毎に分離して構成されていることを特徴とする請求項１に記載の発光素子。 The second color conversion layer provided on the second electrode is further provided, and the second color conversion layer is configured to be separated for each pixel. Light emitting element.
  13. 　請求項１から１２のいずれか一項に記載の前記発光素子を備えたことを特徴とするパッシブマトリクス型表示装置。 A passive matrix display device comprising the light emitting element according to any one of claims 1 to 12.
  14. 　請求項１から１２のいずれか一項に記載の前記発光素子を備えたことを特徴とするアクティブマトリクス型表示装置。 An active matrix display device comprising the light emitting element according to any one of claims 1 to 12.
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