WO2014084308A1 - Élément el organique, et dispositif d'affichage d'image et dispositif d'éclairage équipés dudit élément el organique - Google Patents

Élément el organique, et dispositif d'affichage d'image et dispositif d'éclairage équipés dudit élément el organique Download PDF

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WO2014084308A1
WO2014084308A1 PCT/JP2013/082046 JP2013082046W WO2014084308A1 WO 2014084308 A1 WO2014084308 A1 WO 2014084308A1 JP 2013082046 W JP2013082046 W JP 2013082046W WO 2014084308 A1 WO2014084308 A1 WO 2014084308A1
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layer
organic
refractive index
light
electrode
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PCT/JP2013/082046
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Japanese (ja)
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祐介 山▲崎▼
伸浩 名取
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昭和電工株式会社
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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
    • H10K59/80—Constructional details
    • H10K59/805—Electrodes
    • H10K59/8051—Anodes
    • H10K59/80515—Anodes characterised by their shape
    • 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
    • H10K59/879—Arrangements for extracting light from the devices comprising refractive means, e.g. lenses
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/12—Light sources with substantially two-dimensional radiating surfaces
    • H05B33/22—Light sources with substantially two-dimensional radiating surfaces characterised by the chemical or physical composition or the arrangement of auxiliary dielectric or reflective layers
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/12—Light sources with substantially two-dimensional radiating surfaces
    • H05B33/26—Light sources with substantially two-dimensional radiating surfaces characterised by the composition or arrangement of the conductive material used as an electrode
    • H05B33/28—Light sources with substantially two-dimensional radiating surfaces characterised by the composition or arrangement of the conductive material used as an electrode of translucent electrodes
    • 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
    • H10K2102/351—Thickness

Definitions

  • the present invention relates to an organic EL element, and an image display device and an illumination device including the organic EL element.
  • An organic EL (electroluminescence) element has features such as a wide viewing angle, high-speed response, and clear self-luminous display. In addition, it is expected as a pillar of next-generation lighting devices, image display devices, and the like because of its thin and light weight and low power consumption.
  • Organic EL elements are classified into a bottom emission type in which light is extracted from the support substrate side and a top emission type in which light is extracted from the opposite side of the support substrate, depending on the direction in which the light generated in the organic light emitting layer is extracted. .
  • a bottom emission type organic EL element In a bottom emission type organic EL element, light incident on the transparent substrate out of the light emitted from the light emitting layer passes through the transparent substrate and is extracted outside the element. Of the light emitted from the light emitting layer, the light incident on the interface between the transparent substrate (for example, glass (refractive index: 1.52)) and air (refractive index: 1.0) at a small incident angle below the critical angle is Then, the light is refracted at the interface and taken out of the element. In this specification, these lights are called external mode lights.
  • the light incident on the interface between the transparent substrate and air at an incident angle larger than the critical angle is totally reflected at the interface and is not taken out of the device, and finally Can be absorbed by the material.
  • this light is referred to as substrate mode light, and the loss due to this is referred to as substrate loss.
  • an anode made of a transparent conductive oxide (for example, indium tin oxide (ITO (refractive index: 1.82)) and a transparent substrate (for example, glass (refractive index: 1.52))
  • ITO indium tin oxide
  • a transparent substrate for example, glass (refractive index: 1.52)
  • the light incident on the metal cathode and coupled with the free electron vibration of the metal cathode, and the light captured on the surface of the metal cathode as surface plasmon polariton (SPP) is also outside the device. It is not removed and can eventually be absorbed by the material. In this specification, this light is referred to as SPP mode light, and the loss due to this is referred to as plasmon loss.
  • the light extraction efficiency of the organic EL element is generally limited to about 20% (for example, Patent Document 1). That is, about 80% of the light emitted from the light emitting layer is lost, and it is a big problem to reduce these losses and improve the light extraction efficiency.
  • the extraction of the substrate mode light can be dealt with by providing a light diffusion sheet or the like on the transparent substrate (for example, Patent Document 2). Research on the reduction and extraction of guided mode light and SPP mode light, particularly the reduction and extraction of SPP mode light, has just started.
  • Patent Document 3 discloses a configuration in which a high refractive index layer having a higher refractive index than that of an organic light emitting layer or a transparent electrode is inserted in the vicinity of the organic light emitting layer.
  • Patent Document 2 discloses a configuration in which the refractive index of the organic light emitting layer and the transparent electrode is equivalently lowered by dispersing fine particles having a refractive index lower than that of the organic light emitting layer and the transparent electrode in the organic light emitting layer and the transparent electrode. ing.
  • Patent Documents 4 and 5 disclose a configuration in which cavities (holes) are formed in an anode layer and a dielectric layer sequentially formed on a substrate. Light incident on the side surface of the cavity (interface extending perpendicular to the substrate) is refracted toward the substrate at this interface. With this effect, the ratio of light that causes total reflection can be reduced by changing the incident angle of the guided mode light to a small angle.
  • Patent Documents 6 to 9 As a method for extracting the SPP mode light trapped on the surface of the metal cathode, a configuration in which a periodic uneven structure is formed on the surface of the metal cathode is known (Patent Documents 6 to 9).
  • An organic EL element is usually configured by sandwiching a light emitting layer between an anode and a cathode, and an electron transport layer, an electron injection layer, and the like are laminated between the light emitting layer and the cathode. Therefore, as a method to suppress the influence of SPP trapped by the cathode and increase the light extraction efficiency, it is proposed to increase the film thickness of the electron transport layer, electron injection layer, etc., and physically move the light emitting layer away from the cathode. (For example, Non-Patent Document 1 and Non-Patent Document 2).
  • the conventional method has a problem that the driving voltage of the organic EL element increases because the organic layer between the light emitting layer and the cathode is thickened. Therefore, from the viewpoint of improving power efficiency, it has been difficult to make the organic layer thick enough to suppress the influence of SPP.
  • the organic layer is made thicker, the proportion of guided mode light increases, the light emitted from the light emitting layer is confined in the organic layer, the proportion of light extracted outside the organic EL element decreases, and the luminous efficiency is increased. There was a problem of being lowered. Furthermore, even if the SPP mode light is suppressed and light is extracted into the organic layer, the light extraction efficiency cannot be improved unless the propagating light in the organic layer can be extracted outside the device.
  • An object of the present invention is to provide an organic EL element with improved light extraction efficiency, and an image display device and an illumination device including the organic EL element.
  • the inventors first increase the distance between the light emitting position and the cathode by increasing the thickness of a layer that is disposed in an organic layer such as an electron transport layer or an electron injection layer and has at least a property of transporting electrons. Thus, the energy transfer is suppressed and the SPP generation itself is reduced. Next, it is assumed that the SPP mode light generated is not suppressed even by the thickening, and the generated SPP mode light is taken out into the organic layer. Furthermore, an effective structure that improves the light extraction efficiency out of a number of structures, assuming a light extraction mechanism that extracts the light in the extracted organic layer to the outside of the device without using it as waveguide mode light. We have studied earnestly.
  • the light extraction mechanism for the generated SPP mode light consists of the following two steps.
  • the second electrode side structure of the Otto type arrangement Non-Patent Document 1 that extracts the generated SPP mode light into the organic layer
  • the first electrode side structure that extracts the light in the organic layer to the outside.
  • one of the first electrode and the second electrode is an anode and the other is a cathode.
  • a configuration in which the first electrode is an anode and the second electrode is a cathode will be described as an example.
  • > ⁇ 2 are always satisfied in the light emission frequency region of the element. Therefore, the wave number k sp of SPP is larger than the wave number k of propagating light, and the dispersion curve of SPP does not intersect with the normal dispersion light dispersion line. That is, normal propagating light cannot excite SPP on a flat metal surface. Also, it is not possible to directly extract propagating light from SPP existing on a flat metal surface.
  • an organic EL element for example, when an Otto type arrangement structure in which an organic layer is a high refractive index dielectric is provided, a predetermined incident angle (SPP dispersion curve and evanescent wave dispersion) of light emitted from the organic layer is provided.
  • SPP dispersion curve and evanescent wave dispersion Light incident on the low refractive index dielectric layer from the organic layer at an angle that intersects the straight line) becomes an evanescent wave and excites SPP mode light on the metal surface.
  • the SPP mode light excited on the metal surface can be extracted as propagating light into the organic layer via the evanescent wave generated in the Otto type arrangement structure.
  • the light extracted from the SPP is radiated at a predetermined angle corresponding to the intersection of the SPP dispersion curve and the evanescent wave dispersion line.
  • the SPP mode light extracted up to the organic layer by the above Otto type arrangement may be totally reflected on the surface of the cathode opposite to the organic layer and confined in the organic layer to become a waveguide mode. Therefore, even if the SPP mode light can be extracted, the effect of improving the light extraction efficiency is insufficient. Therefore, an organic layer such as an electron transport layer, an electron injection layer, or a hole blocking layer is further disposed between the light emitting layer and the metal layer in the organic layer. With these layers constituting the organic layer, the distance between the metal layer and the light emitting layer can be increased, and SPP mode light can be further suppressed.
  • the anode side structure has a refractive index that is perpendicular or nearly perpendicular to the substrate surface (a plane parallel to the light emitting surface) so that the light propagating in the organic layer is refracted and the propagation angle after refraction is reduced.
  • the interface of was introduced.
  • An organic EL element comprising a first electrode, an organic layer including a light emitting layer made of an organic EL material, and a second electrode in this order, on the opposite side of the second electrode from the organic layer, A low refractive index layer and a metal layer are provided in order, the refractive index of the low refractive index layer is lower than the refractive index of the organic layer, the organic layer is between the light emitting layer and the second electrode, An organic EL element comprising an organic thick film layer having a thickness of 10 nm to 300 nm, wherein a distance between the light emitting layer and the metal layer is 100 nm to 400 nm.
  • the organic thick film layer is composed of n layers (n is an integer of 1 or more), and the film thickness and mobility of the i-th (i is an integer from 1 to n) sub-layer are set to di and ⁇
  • ⁇ indicates that the sum for all the sublayers is taken.
  • the unit of the above formula is SI unit system.
  • (3) The organic EL element according to (1) or (2), wherein the refractive index of the low refractive index layer is further lower than the refractive index of the second electrode.
  • the organic EL element according to (3) wherein a refractive index of the second electrode is lower than a refractive index of the organic layer.
  • the low refractive index layer is made of a material having a refractive index smaller by 0.2 or more than at least one of the second electrode and the organic layer.
  • a dielectric layer having a refractive index lower than the refractive index of the organic layer and having a plurality of holes is provided between the first electrode and the second electrode.
  • the organic EL device according to (6) wherein the organic layer further includes a layered portion disposed between the dielectric layer and the hole side surface covering portion and the second electrode. .
  • the first electrode includes a first electrode hole portion that communicates with the hole portion, and the organic layer further includes a first electrode hole inner surface covering portion that covers an inner surface of the first electrode hole portion.
  • the organic EL device according to (6) which has (9) The organic EL device according to (8), wherein the organic layer further includes a layered portion disposed between the dielectric layer and the hole side surface covering portion and the second electrode. .
  • a substrate is provided on a side opposite to the organic layer of the first electrode, the substrate includes a recess communicating with the first electrode hole, and the organic layer further includes a recess covering the inner surface of the recess.
  • the organic EL device according to any one of (8) and (9), which has an inner surface covering portion.
  • An organic EL element comprising a first electrode, an organic layer including a light emitting layer made of an organic EL material, and a second electrode in this order, on the opposite side of the second electrode from the organic layer, A low refractive index layer and a metal layer are provided in order, the refractive index of the low refractive index layer is lower than the refractive index of the organic layer, and the first electrode has a refractive index lower than the refractive index of the first electrode.
  • a plurality of first electrode hole portions whose inner side surfaces are covered with a dielectric layer having the organic layer, and the organic layer has an organic thickness of 10 nm or more and 300 nm or less between the light emitting layer and the second electrode.
  • An organic EL element comprising a film layer, wherein a distance between the light emitting layer and the metal layer is 100 nm or more and 400 nm or less.
  • An organic EL element comprising a first electrode, an organic layer including a light emitting layer made of an organic EL material, and a second electrode in this order, on the side opposite to the organic layer of the second electrode, A low refractive index layer and a metal layer are provided in order, the refractive index of the low refractive index layer is lower than the refractive index of the organic layer, the first electrode includes a plurality of first electrode holes, and the organic layer The layer includes an organic thick film layer having a thickness of 10 nm to 300 nm between the light emitting layer and the second electrode, and a distance between the light emitting layer and the metal layer is 100 nm to 400 nm.
  • the organic layer has a first electrode hole inner surface covering portion that covers an inner surface of the first electrode hole portion.
  • An organic EL element comprising a dielectric layer, a first electrode, an organic layer including a light emitting layer made of an organic EL material, and a second electrode in order, wherein the organic layer of the second electrode Comprises a low refractive index layer and a metal layer in this order on the opposite side, the refractive index of the low refractive index layer being lower than the refractive index of the organic layer, the organic layer comprising the light emitting layer and the second electrode Between the light emitting layer and the metal layer is 100 nm or more and 400 nm or less, and the dielectric layer is formed of the first electrode.
  • the first electrode, the organic layer, the second electrode, the low-refractive-index layer, and the metal layer are formed of a pattern having a refractive index lower than the refractive index and having an opening. It is formed so as to follow the pattern of the layer, The organic EL element that.
  • An organic EL element comprising a first electrode, an organic layer including a light emitting layer made of an organic EL material, and a second electrode in this order, on the side opposite to the organic layer of the second electrode, A low refractive index layer and a metal layer are provided in order, the refractive index of the low refractive index layer is lower than the refractive index of the organic layer, the organic layer is between the light emitting layer and the second electrode, An organic thick film layer having a thickness of 10 nm or more and 300 nm or less, a distance between the light emitting layer and the metal layer being 100 nm or more and 400 nm or less, and a diffraction grating on a side opposite to the organic layer of the first electrode, An organic EL device having any one of a lens structure, a sawtooth structure, and a scattering layer.
  • the organic thick film layer is composed of n layers (n is an integer of 1 or more), and the film thickness and mobility of the i-th (i is an integer from 1 to n) sub-layer are set to di and ⁇ i, respectively.
  • the organic EL element according to any one of (11) to (14), wherein the relationship of the following formula is satisfied; 10 ⁇ 15 [s ⁇ V] ⁇ ⁇ (d i 2 / ⁇ i ) ⁇ 10 ⁇ 4 [s ⁇ V] (I 1, 2, 3,...)
  • ⁇ indicates that the sum for all the sublayers is taken.
  • the unit of the above formula is SI unit system.
  • An image display device comprising the organic EL element according to any one of (1) to (15).
  • An illumination device comprising the organic EL element according to any one of (1) to (15).
  • an organic EL device having improved light extraction efficiency by suppressing the generation of SPP mode light itself and effectively extracting the generated SPP mode light and waveguide mode light, and the same are provided.
  • An image display device and a lighting device can be provided.
  • the first electrode is described as an anode and the second electrode as a cathode.
  • the first electrode may be a cathode and the second electrode may be an anode.
  • FIG. 1 is a schematic cross-sectional view for explaining an example of the organic EL element according to the first embodiment of the present invention.
  • An organic EL device 10 according to the first embodiment of the present invention includes an anode (first electrode) 2, an organic layer 103 including a light emitting layer 3 made of an organic EL material, and a cathode (second electrode) on a substrate 1. Electrode) 4 in this order, and a low refractive index layer 5 and a metal layer 6 in this order on the opposite side of the cathode 4 from the organic layer 3.
  • the refractive index of the low refractive index layer 15 is lower than the refractive index of the organic layer.
  • the organic layer 103 includes an organic thick film layer 18 having a thickness of 10 nm to 300 nm between the light emitting layer 3 and the cathode 4.
  • the distance between the light emitting layer 3 and the metal layer 6 is 100 nm or more and 400 nm or less.
  • the film thickness of the organic thick film layer means an average distance between the light emitting layer 3 and the cathode 4 on the metal layer 6 side.
  • the refractive index of the low refractive index layer 5 is preferably lower than the refractive index of the cathode 4.
  • the refractive index of the cathode 4 is preferably lower than the refractive index of the organic layer 3.
  • the refractive index of the organic layer refers to the average refractive index of all layers (including a light emitting layer made of an organic EL material) constituting the organic layer.
  • the organic layer 3 shown in FIG. 1 further includes a layer 19 having a function of transporting at least holes, such as a hole transport layer and a hole injection layer.
  • the refractive index of the low refractive index layer is lower than the refractive index of the organic layer.
  • n L , n C , and n O refractive indexes of the low refractive index layer, the cathode, and the organic layer
  • B pattern n L ⁇ n O ⁇ n C
  • n L ⁇ There are three cases: n C ⁇ n O (hereinafter referred to as “C pattern”) and n C ⁇ n L ⁇ n O (hereinafter referred to as “D pattern”).
  • C pattern n C ⁇ n O
  • D pattern n C ⁇ n L ⁇ n O
  • the configuration of the metal layer / low refractive index layer / cathode is an Otto type arrangement.
  • the configuration of the metal layer / low refractive index layer / cathode is an Otto type arrangement
  • the configuration of metal layer / low refractive index layer + cathode / organic layer is also an Otto type arrangement.
  • the configuration of the metal layer / low refractive index layer + cathode / organic layer is an Otto type arrangement.
  • the thickness of the cathode and the low refractive index layer is preferably 30 nm to 1 ⁇ m, the light extraction efficiency is improved regardless of the cathode thickness in the B pattern and the C pattern, and the cathode thickness is increased in the D pattern. It was confirmed by the simulation detailed later that the effect of the Otto type arrangement decreases with increasing thickness.
  • the most preferable B to D pattern is the C pattern.
  • the configuration of the metal layer / low refractive index layer / cathode is an Otto type arrangement
  • the configuration of metal layer / low refractive index layer + cathode / organic layer is also an Otto type arrangement. Therefore, re-radiation of SPP mode light is most likely to occur from the metal layer. Furthermore, since the refractive index increases in the order of the low refractive index layer, the cathode, and the organic layer, total reflection does not occur at each interface, and the re-radiated SPP mode light is extracted as it is to the substrate side.
  • the low refractive index layer may be air or SOG (spin on glass), and the cathode may be a transparent conductive material layer such as ITO.
  • the B pattern In this case, the configuration of the metal layer / low refractive index layer / cathode is an Otto type arrangement. Therefore, re-radiation of SPP mode light occurs from the metal layer.
  • the refractive index of the organic layer is an intermediate value between the low refractive index layer and the cathode, some of the re-radiated SPP mode light is totally reflected at the cathode / organic layer interface, and the remaining light is reflected. Permeates the organic layer.
  • the D pattern is preferred.
  • the configuration of the metal layer / low refractive index layer / cathode is not an Otto type arrangement.
  • the structure of the metal layer / low refractive index layer + cathode / organic layer is an Otto type arrangement, re-radiation of SPP mode light occurs from the metal layer.
  • the re-radiation of the SPP mode light is further reduced than in the case of the B pattern.
  • a cathode for example, ITO
  • an organic layer are selected so as to satisfy n C ⁇ n O depending on the magnitude of the refractive index, and the refractive index n L is n C and n O as a low refractive index layer.
  • SOG may be employed.
  • n O ⁇ n C ⁇ n L (hereinafter referred to as “E pattern”) and in the case of n C ⁇ n O ⁇ n L (hereinafter also referred to as “F pattern”), the Otto type arrangement is not achieved.
  • n O ⁇ n L ⁇ n C (hereinafter referred to as “A pattern”), the metal layer / low refractive index layer / cathode is in an Otto type arrangement, and re-emission of SPP mode light occurs from the metal layer.
  • the substrate 1 is a translucent substrate in the case of a bottom emission type organic EL element, and usually needs to be transparent to visible light.
  • transparent to visible light means that it is only necessary to transmit visible light having a wavelength emitted from the light emitting layer, and does not need to be transparent over the entire visible light region.
  • a smooth substrate having a transmittance in visible light of 400 to 700 nm of 50% or more is preferable.
  • glass plates and polymer plates examples include soda lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz.
  • the polymer plate examples include polycarbonate, acrylic, polyethylene terephthalate, polyethylene naphthalate, polyether sulfide, and polysulfone.
  • the transmittance is preferably 50% or more and more preferably 70% or more with respect to the wavelength at which light emission has the maximum intensity.
  • a bottom emission type element that extracts light from the substrate side
  • light is emitted from the side opposite to the substrate (second electrode side).
  • an opaque material can be used in addition to the same as described above.
  • a metal material such as stainless steel, Si, SiC, AlN, GaN, Nonmetallic materials such as GaAs and sapphire, and other substrate materials usually used in top emission type organic EL elements can be used.
  • a material having high thermal conductivity is preferably used for the substrate.
  • the thickness of the substrate 1 is not limited because it depends on the required mechanical strength, but is preferably 0.01 mm to 10 mm, more preferably 0.05 mm to 2 mm.
  • the anode 2 is an electrode for applying a voltage to the organic layer 3 between the anode 4 and injecting holes into the organic layer 3 including the light-emitting layer from the anode 2. It is preferable to use a material comprising a compound or a mixture thereof. It is preferable to use one having a work function of 4 eV or more and 6 eV or less so that the difference from the HOMO (Highest Occupied Molecular Orbital) level of the organic layer in contact with the anode does not become excessive.
  • the material of the anode 2 is not particularly limited as long as it is a translucent and conductive material.
  • transparent inorganic oxides such as indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide, zinc oxide, PEDOT: PSS (poly (3,4-ethylenedioxythiophene) -poly (styrenesulfonic acid) ), Conductive polymers such as polyaniline, and conductive polymers doped with any acceptor, and transparent carbon materials such as carbon nanotubes and graphene.
  • the anode 2 can be formed on the substrate 1 by, for example, a sputtering method, a vacuum deposition method, a coating method, or the like.
  • the thickness of the anode 2 is not particularly limited, but is, for example, 10 to 2000 nm, preferably 50 to 1000 nm. When the thickness of the anode 2 is less than 10 nm, the waveguide mode light is hardly scattered. If the thickness of the anode 2 is larger than 2000 nm, the flatness of the organic layer 103 cannot be maintained and the transmittance of the anode is lowered.
  • the cathode 4 is an electrode for injecting electrons into the light emitting layer, and it is preferable to use a material made of a metal, an alloy, a conductive compound, or a mixture thereof having a small work function. It is preferable to use a material having a work function of 1.9 eV or more and 5 eV or less so that the difference from the LUMO (Lowest Unoccupied Molecular Orbital) level of the organic layer 3 in contact with the cathode 4 does not become excessive.
  • LUMO Local Unoccupied Molecular Orbital
  • the refractive index of the cathode 4 is preferably lower than the refractive index of the organic layer 3.
  • the thickness of the cathode 4 is not particularly limited, but is, for example, 30 nm to 1 ⁇ m, preferably 50 to 500 nm, and more preferably 30 to 350 nm. If the thickness of the cathode 4 is less than 30 nm, the sheet resistance increases and the driving voltage rises. When the thickness of the cathode 4 is greater than 1 ⁇ m, damage due to heat and radiation during film formation and mechanical damage due to film stress accumulate in the electrode and the organic layer.
  • the organic layer 103 includes a light emitting layer 3 made of an organic EL material, and includes an organic thick film layer 18 having a thickness of 10 nm to 300 nm between the light emitting layer 3 and the cathode 2.
  • the thickness of the organic thick film layer 18 is preferably 20 to 300 nm, more preferably 50 to 200 nm, and still more preferably 100 to 150 nm.
  • the thickness of the organic thick film layer 18 is less than 10 nm, the carrier balance between holes and electrons is lost, the internal quantum efficiency is lowered, and even when the Otto type arrangement is combined, the suppression of the SPP mode is insufficient.
  • the thickness of the organic thick film layer 18 exceeds 300 nm, the driving voltage increases.
  • the organic thick film layer 18 is a layer thickened to effectively suppress energy transfer between the light emitting position and the cathode, and there is no particular limitation on the material as long as it has a property of transporting at least electrons. .
  • the organic thick film layer 18 may be an electron injection layer or an electron transport layer, or may be composed of a plurality of layers including them.
  • the electron injection layer generally has a function of improving the efficiency of electron injection from the cathode 4 and is a layer having an effect of lowering the driving voltage of the element.
  • the electron transport layer is a layer having a function of efficiently transporting electrons. Further, it may have a function of suppressing the movement of holes.
  • the layer 19 shown in FIG. 1 may be a hole injection layer or a hole transport layer, or may be composed of a plurality of layers including them.
  • the first electrode is an anode and the second electrode is a cathode.
  • the organic EL element according to the present invention may have a configuration in which the first electrode is a cathode and the second electrode is an anode as described above.
  • the organic thick film layer 18 may include a hole injection layer or a hole transport layer
  • the layer 19 shown in FIG. 1 may include an electron injection layer or an electron transport layer.
  • the organic layer 3 may include a layer made of another organic material.
  • the organic thick film layer is not so conductive, there is a problem that the drive voltage increases when the organic thick film layer is thick. Therefore, it is preferable to use a material with high mobility in order to suppress an increase in driving voltage even when the organic thick film layer is thickened.
  • the relationship between the film thickness and mobility of the organic thick film layer can be expressed by d 2 / ⁇ (d is the film thickness, and ⁇ is the mobility). This corresponds to the resistance of the layer.
  • the organic thick film layer is composed of n layers (n is an integer of 1 or more), and the film thickness and mobility of the i-th (i is an integer from 1 to n) sub-layer are d i and ⁇ i , respectively.
  • n is an integer of 1 or more
  • the film thickness and mobility of the i-th (i is an integer from 1 to n) sub-layer are d i and ⁇ i , respectively.
  • ⁇ indicates that the sum for all the sublayers is taken.
  • the organic thick film layer is a single layer, the value of ⁇ is d 2 / ⁇ .
  • the unit of the above formula is the SI unit system.
  • the organic thick film layer is preferably within the range of the above formula.
  • the above formula is 10 ⁇ 15 [s ⁇ V] or more, the number of carriers is reduced, and light absorption can be suppressed by the organic layer.
  • the above formula is 10 ⁇ 4 [s ⁇ V] or less, the organic layer has a low resistance and an increase in driving voltage can be suppressed.
  • the above formula is preferably 10 ⁇ 11 [s ⁇ V] or more, more preferably 10 ⁇ 7 [s ⁇ V] or more, and further preferably 10 ⁇ 5 [s ⁇ V]. ] The following should be used.
  • the voltage value of the formula (5) is preferably 1.0 V or less, more preferably 0.5 V or less, and 0.3 V More preferably, it is as follows.
  • the value of the current density j 0.1 mA / cm 2 can be used as a typical value usually used in driving the organic EL element.
  • the organic layer 103 may be formed by a dry process such as an evaporation method or a transfer method. Alternatively, the film may be formed by a wet process such as a spin coating method, a spray coating method, a die coating method, or a gravure printing method.
  • the thickness of the organic layer 103 is not limited, but is, for example, 50 to 2000 nm, and preferably 100 to 1000 nm. When the layer thickness of the organic layer 103 is less than 50 nm, quenching other than SPP coupling by metal, such as reduction of internal QE due to punch-through current and lossy surface wave mode coupling, occurs. When the organic layer 103 is thicker than 1000 nm, the driving voltage increases.
  • the low refractive index layer 5 is provided on the opposite side of the cathode 4 from the organic layer 103 and is made of a material having a refractive index lower than that of the organic layer 103. Further, it is preferable to be made of a material having a lower refractive index than the translucent conductive material constituting the cathode 4.
  • the low refractive index layer 5 is more preferably made of a material having a refractive index smaller by 0.2 or more than at least one of the cathode 4 and the organic layer 103.
  • the material for the low refractive index layer 5 is not particularly limited as long as it is a material having a lower refractive index than the material constituting the organic layer 103.
  • halides such as spin-on-glass (SOG (typical refractive index 1.25)), magnesium fluoride (MgF 2 (refractive index 1.38)), polytetrafluoroethylene (PTFE (refractive index 1.35)) ), Etc., silicon dioxide (SiO 2 (refractive index 1.45)), various low-melting glasses, and porous materials.
  • the low refractive index layer 5 is a layer including an air layer, and may have a lower refractive index than the translucent conductive material constituting the cathode 4. The same applies to later-described embodiments.
  • the thickness of the low refractive index layer 5 is not particularly limited, but is, for example, 20 nm to 1 ⁇ m, preferably 20 to 350 nm, more preferably 50 to 200 nm. If the thickness of the low refractive index layer 5 is less than 20 nm, the SPP is affected by the cathode 4 and the wave number becomes larger than the formula (1), and the SPP is not extracted into the organic layer 3 (propagation light of the organic layer 3 And disperse.) If the thickness of the low refractive index layer 5 is greater than 1 ⁇ m, the evanescent wave of the propagating light in the organic layer 3 will not reach the cathode 4 and SPP will not be extracted.
  • the metal layer 6 is provided on the opposite side of the cathode 4 from the organic layer 103 via a low refractive index layer 5. Since the metal layer 6 is used as a reflective layer for emitted light, a layer with good reflectivity is preferable.
  • the metal layer 6 may have a laminated structure of two or more layers.
  • the above-described material with good reflectivity is likely to cause plasmon resonance due to light emitted from the light emitting layer, but can suppress plasmon resonance by the above-described cathode-side structure of the Ototo type arrangement and the organic thick film layer.
  • the thickness of the metal layer 6 is not particularly limited, but is, for example, 20 to 2000 nm, preferably 50 to 500 nm. When the thickness of the metal layer 6 is less than 20 nm, the reflectance is lowered and the front luminance is lowered. When the thickness of the metal layer 6 is greater than 500 nm, damage due to heat and radiation during film formation and mechanical damage due to film stress accumulate in the electrode and the organic layer.
  • FIG. 2 is a schematic cross-sectional view for explaining an example of the organic EL element according to the second embodiment of the present invention.
  • An organic EL device 20 according to the second embodiment of the present invention includes, on a substrate 11, an anode 12, an organic layer 13 including a light emitting layer 3 made of an organic EL material, and a cathode 14 in this order. 14 is provided with a low refractive index layer 15 and a metal layer 16 in this order on the side opposite to the organic layer 13.
  • the organic layer 13 includes an organic thick film layer 18 having a thickness of 10 nm to 300 nm between the light emitting layer 3 and the cathode 14.
  • the distance between the light emitting layer 3 and the metal layer 16 is 100 nm or more and 400 nm or less.
  • the refractive index of the low refractive index layer 15 is lower than the refractive index of the organic layer.
  • a dielectric layer 17 having a refractive index lower than that of the organic layer 13 and having a plurality of hole portions 17A is provided between the anode 12 and the cathode 14.
  • the organic layer 13 has a hole inner side surface covering portion 13a that covers the inner surface 17a of the hole portion 17A.
  • the anode 12 includes an anode hole portion 12 ⁇ / b> A (see FIG. 10G) that communicates with the hole portion 17.
  • the substrate 11 includes a recess 11A (see FIG.
  • the organic layer 13 further includes an anode (first electrode) hole inner side surface covering portion 13b covering the inner side surface 12a of the anode (first electrode) hole portion 12A, and a concave portion covering the inner side surface 11a of the concave portion 11A. And a side surface covering portion 13c.
  • the hole inner surface covering portion, the anode hole inner surface covering portion, and the concave inner surface covering portion may be constituted by a part of the layers constituting the organic layer.
  • the organic layer 13 further includes a layered portion 13 d disposed between the dielectric layer 17 and the hole inner surface covering portion 13 a and the cathode 14.
  • the layered portion 13 d includes the light emitting layer 3 and the organic thick film layer 18.
  • the organic layer 13 shown in FIG. 2 further includes a layer 19 having a function of transporting at least holes, such as a hole transport layer and a hole injection layer, on the anode side from the light emitting layer 3.
  • the hole inner surface covering portion, the anode hole inner surface covering portion, and the concave inner surface covering portion may be constituted by a part of the layers constituting the organic layer.
  • the shape of the hole, the anode hole, and the recess is not particularly limited as long as it has an effect of refracting light toward the substrate on the inner surface thereof.
  • a shape in which the area on the hole on the cathode 14 side is smaller than the area on the bottom of the hole on the substrate 11 side is preferable.
  • a shape in which the hole bottom area on the substrate 11 side is smaller than the hole upper area on the cathode 14 side is preferable.
  • the area of the bottom surface of the hole is preferably as small as possible. Therefore, it is desirable that these shapes themselves are small.
  • those inner side surfaces are arranged to be perpendicular to the substrate surface, but such a configuration is not necessary.
  • the angle of the inner side surface of the anode hole portion with respect to the substrate surface is preferably 30 ° or more, more preferably 45 ° or more, and still more preferably 60 ° or more. Further, it may be reverse tapered (the bottom surface of the hole on the substrate 11 side is larger than the top surface of the hole on the light emitting layer 3 side).
  • the substrate 11 since the substrate 11 includes a plurality of recesses 11A, it is preferable that the substrate 11 be a material that can be processed more accurately. Although it does not limit as a preferable material, For example, quartz is mentioned.
  • the anode 12 includes a plurality of anode hole portions 12A (see FIG. 10H), and the inner side surface 12a of the anode hole portion 12A is covered with an organic layer 13 (anode hole inner side surface covering portion 13b). ). Further, the upper surface of the anode 12 is characterized by being covered with a dielectric layer 17. As long as the anode hole inner side surface covering portion 13b covers the inner side surface 12a, the anode hole inner surface covering portion 13a may be filled or may be partially filled.
  • the dielectric layer 17 has a refractive index lower than that of the organic layer 13 and includes a plurality of holes 17A.
  • the inner side surface 17a of the hole 17A is covered with the organic layer 13 (hole inner side surface covering portion 13a).
  • the hole inner surface covering portion 13a may be filled with the hole portion 17A or may be partially filled.
  • the refractive index of the organic layer refers to all the layers constituting the organic layer (including a light emitting layer made of an organic EL material). The average refractive index. The same applies to dielectric layers in the embodiments described later.
  • the material of the dielectric layer 17 is not particularly limited as long as the material has a refractive index lower than that of the organic layer 13.
  • the refractive index of the organic layer 13 is 1.72, for example, a metal fluoride such as SOG (refractive index 1.25) or MgF 2 (1.38), an organic fluorine compound such as PTFE, SiO 2 (1 .45), various low-melting-point glasses, and porous materials.
  • the thickness of the dielectric layer 17 is not particularly limited. For example, it is 10 to 2000 nm, preferably 50 to 1000 nm. If the thickness of the dielectric layer 17 is less than 10 nm, the volume of the dielectric layer 17 with respect to the organic layer becomes small, and the light enters the side surface of the hole 17A from the organic layer 13 but is hardly refracted. When the thickness of the dielectric layer 17 is greater than 2000 nm, it becomes difficult to maintain the flatness of the organic layer 13.
  • the organic layer 13 includes a light emitting layer 3 made of an organic EL material, and includes an organic thick film layer 18 having a thickness of 10 nm to 300 nm between the light emitting layer 3 and the cathode 14. The distance between the light emitting layer 3 and the metal layer 16 is not less than 100 nm and not more than 400 nm.
  • the organic layer 13 includes a layer 19 having a function of transporting at least holes, such as a hole transport layer and a hole injection layer.
  • the organic layer 13 includes a hole inner surface covering portion 13a that covers the inner surface 17a of the hole portion 17A, an anode hole inner surface covering portion 13b that covers the inner surface 12a of the anode hole portion 12A, and the recess 11A.
  • the organic layer 13 further has a layered portion 13 d disposed between the dielectric layer 17 and the hole inner side surface covering portion 13 a and the cathode 14.
  • the effect of the organic EL element of this embodiment is typically demonstrated using FIG.
  • the organic thick film layer 18 has a thickness of 10 nm or more, and the distance between the light emitting layer 3 and the cathode 14 is large, so that energy transfer is difficult and SPP mode light is generated. Itself is suppressed.
  • the propagation method of the light indicated by the arrows in FIG. 2 is used in order to easily explain how the generated SPP mode light is extracted by the characteristic configuration of this embodiment and the principle of its effect. It is shown schematically.
  • a light emission point (or light emission location) APi indicates a light emission point at a position overlapping the anode hole 12A in plan view (hereinafter, light emission at this point may be referred to as “in light emission”).
  • the light emission point APo indicates a light emission point at a position overlapping the dielectric layer 17 in plan view (hereinafter, light emission at this point may be referred to as “out light emission”).
  • the light emission point APe indicates light emission at a boundary position between “in light emission” and “out light emission” (hereinafter, light emission at this point may be referred to as “in-out edge light emission”).
  • the arrow AP1 merely schematically shows the propagation of a part of the light in order to explain the function and effect of the present invention.
  • the light indicated by the arrow AP2 and the arrows BP1 to BP4 and the light indicated by the arrows CP1 to CP4 to be described later are merely shown schematically for the propagation of part of the light. The same applies to the light emitted at the APo point and the APe point.
  • refraction occurs at the interface of materials having different refractive indexes, the refraction action is not shown at the interface in the figure which is not particularly necessary for explaining the effects of the present invention.
  • the light extracted from the cathode side structure (cathode 14, low refractive index layer 15, metal layer 16) to the BP point of the organic layer 13 propagates like BP1 and is extracted to the substrate 11. That is, the light BP1 (waveguide mode light) traveling through the organic layer 13 from the BP point is refracted at the interface between the organic layer 13 and the dielectric layer 17 (the inner side surface 17a of the hole 17A). The refracted light passes through the dielectric layer 17, refracts at the interface between the dielectric layer 17 and the anode 12, travels through the anode 12, refracts at the interface between the anode 12 and the substrate 11, and then passes through the substrate 11. It can be taken out through.
  • the light BP1 travels from the organic layer 13 to the dielectric layer 17, the light BP1 enters the substrate 11 due to refraction at the interface between the organic layer 13 and the dielectric layer 17 (the inner surface 17a of the hole 17A).
  • the angle changes to a small angle (an angle closer to the direction perpendicular to the substrate 11).
  • the substrate for example, glass
  • the light is refracted by the refraction at the inner surface 17a of the hole 17A and enters the substrate 11.
  • the angle changes to a smaller angle. Therefore, the light that can avoid total reflection at the interface between the substrate and air is increased, and the light extraction efficiency is improved.
  • the light extraction efficiency is improved by having the configuration including the inner surface 17a of the hole 17A.
  • the refraction causes the incident angle to the substrate 11 to change to a small angle. The light that can avoid total reflection at the interface between the substrate and air is increased, and the light extraction efficiency is improved.
  • the vicinity of the shortest distance between the cathode 14 and the anode 12 has the highest current density and the amount of light emission increases.
  • the light emission at the CPl and CPr points of the light emitting layer included in the organic layer 13 schematically shows the light emission at the point where the light emission amount is large.
  • the light CP1 is light that travels to the substrate side in a direction perpendicular to the substrate, and is not refracted at the interface between the organic layer 13 and the substrate 11. It proceeds through the substrate 11 and is taken out to the outside.
  • the light CP2 is refracted at the interface between the organic layer 13a and the dielectric layer 17 (the inner surface 17a of the hole 17A).
  • the refracted light passes through the dielectric layer 17, refracts at the interface between the dielectric layer 17 and the anode 12, travels through the anode 12, refracts at the interface between the anode 12 and the substrate 11, and then passes through the substrate 11. It can be taken out through.
  • the incident angle to the substrate 11 is small due to refraction at the interface between the organic layer 13a and the dielectric layer 17 (the inner surface 17a of the hole 17A). Change to angle.
  • the light CP4 traveling through the organic layer 13 from the CP1 point is an interface between the organic layer 13c and the convex portion 11B of the substrate 11 (inner side surface 11a of the concave portion 11A (the convex portion 11B of the substrate 11 extending perpendicularly to the substrate 11).
  • the refraction causes the incident angle to the substrate 11 to be changed to a small angle.
  • the effect of improving the light extraction efficiency is obtained.
  • the same effect as the light emitted at the CPl point can be obtained.
  • FIG. 3 is a schematic cross-sectional view for explaining an example of the organic EL element according to the third embodiment of the present invention.
  • An organic EL element 30 according to the third embodiment of the present invention includes, on a substrate 21, an anode 22, an organic layer 23 including a light emitting layer 3 made of an organic EL material, and a cathode 24 in this order.
  • the low refractive index layer 25 and the metal layer 26 are sequentially provided on the side opposite to the organic layer 23 of 24.
  • the organic layer 23 includes an organic thick film layer 18 having a thickness of 10 nm to 300 nm between the light emitting layer 3 and the cathode 24.
  • the distance between the light emitting layer 3 and the metal layer 26 is 100 nm or more and 400 nm or less.
  • the refractive index of the low refractive index layer 25 is lower than the refractive index of the organic layer.
  • a dielectric layer 27 having a refractive index lower than that of the organic layer 23 and having a plurality of hole portions 27A is provided between the anode 22 and the cathode 24.
  • the organic layer 23 has at least a hole inner surface covering portion 23a that covers the inner surface 27a of the hole 27A.
  • the organic layer 23 further has a layered portion 23 b disposed between the dielectric layer 27 and the hole inner surface covering portion 23 a and the cathode 24.
  • the layered portion 23 b includes the light emitting layer 3 and the organic thick film layer 18.
  • the organic layer 23 shown in FIG. 3 further includes a layer 19 having a function of transporting at least holes, such as a hole transport layer and a hole injection layer, closer to the anode side than the light emitting layer 3.
  • the hole inner surface covering portion 23 a may be constituted by a part of the layers constituting the organic layer 23.
  • the shape of the hole is not particularly limited as long as it has an effect of refracting light toward the substrate on its inner surface. From the viewpoint of refracting the light in the organic layer 23 more vertically, a shape in which the bottom area on the cathode 24 side is smaller than the bottom area on the anode 22 side is preferable. From the viewpoint of extracting light rays such as BQ1 straight up to the substrate without being refracted, a shape in which the area on the anode 22 side is smaller than the bottom area on the cathode 24 side is preferable. From the viewpoint of strongly diffracting the light in the organic layer 23 and taking it out with a smaller propagation distance, a shape having a bottom area as small as possible is preferable. In the example shown in FIG. 3, the inner side surface is configured to be arranged perpendicular to the substrate surface, but such a configuration is not necessary.
  • the angle of the inner side surface 27a of the hole 27A with respect to the substrate surface is preferably 30 ° or more, more preferably 45 ° or more, and still more preferably 60 ° or more. Further, a reverse taper may be used (the bottom surface of the hole on the substrate 21 side is larger than the top surface of the hole on the light emitting layer 3 side).
  • the dielectric layer 27 has a refractive index lower than that of the organic layer and includes a plurality of holes 27A.
  • the inner surface 27a of the hole 27A is covered with the organic layer 23 (hole inner surface covering portion 23a). As long as the inner surface 27a of the hole covers the inner surface 27a, the hole inner surface 27a may be filled with the hole 27A or may be partially filled.
  • the material and thickness of the dielectric layer 27 the same material and thickness as those of the first embodiment can be used.
  • the organic layer 23 includes a light emitting layer 3 made of an organic EL material, and includes an organic thick film layer 18 having a thickness of 10 nm to 300 nm between the light emitting layer 3 and the cathode 24.
  • the distance between the light emitting layer 3 and the metal layer 26 is 100 nm or more and 400 nm or less.
  • the organic layer 23 includes a hole inner surface covering portion 23a that covers the inner surface 27a of the hole 27A, and a layered portion disposed between the dielectric layer 27 and the hole inner surface covering portion 23a and the cathode 24. 23b.
  • the effect of the organic EL element of this embodiment is typically demonstrated using FIG.
  • the light propagation method indicated by the arrows in FIG. 3 is schematically shown in order to easily understand the principle of the effect.
  • the organic thick film layer 18 has a thickness of 10 nm or more, and the distance between the light emitting layer 3 and the cathode 14 is large. The occurrence itself is suppressed.
  • the propagation method of the light indicated by the arrows in FIG. 3 is used in order to easily understand how the generated SPP mode light is extracted by the characteristic configuration of this embodiment and the principle of its effect. It is shown schematically.
  • the light traveling toward the cathode 24 is incident at the interface between the cathode 24 and the low refractive index layer 25 at an incident angle greater than the critical angle ( Arrow AQ1)
  • an evanescent wave (arrow AQ2) is generated in the low refractive index layer 25.
  • the generated evanescent wave squeezes out to the interface between the metal layer 26 and the low refractive index layer 25, and the SPP (arrow AQ3) is excited.
  • the excited SPP mode light is radiated to the cathode 24 at a predetermined angle (arrow AQ5) via resonance with the evanescent wave (arrow AQ4), and can be extracted to the organic layer 23 as guided mode light.
  • a light emission point (or light emission location) AQi indicates a light emission point at a position overlapping the hole 27A (position facing the anode 22 through the organic layer 23) in plan view (hereinafter this point).
  • the light emission at is sometimes referred to as “in light emission”).
  • the light emission point AQo indicates a light emission point at a position overlapping the dielectric layer 27 in plan view (hereinafter, light emission at this point may be referred to as “out light emission”).
  • the light emission point AQe indicates light emission at the boundary between “in light emission” and “out light emission” (hereinafter, light emission at this point may be referred to as “in-out edge light emission”).
  • the light extracted from the cathode side structure (cathode 24, low refractive index layer 25, metal layer 26) to the BQ point of the low refractive index layer 25 propagates like BQ1 and is extracted to the substrate 21 depending on the angle at which it is extracted. . That is, the light BQ1 traveling through the organic layer 23 from the point BQ is refracted at the interface between the organic layer 23 and the dielectric layer 27 (the inner side surface 27a of the hole 27A). The refracted light passes through the dielectric layer 27, refracts at the interface between the dielectric layer 27 and the anode 22, travels through the anode 22, refracts at the interface between the anode 22 and the substrate 21, and then passes through the substrate 21. It can be taken out through.
  • the incident angle to the substrate 21 is small due to refraction at the interface between the organic layer 23a and the dielectric layer 27 (inner side surface 27a of the hole 27A). Change to angle. Light incident at an angle greater than the critical angle is totally reflected at the interface between the substrate (for example, glass) and air, but the incident angle on the substrate 21 is changed to a small angle by refraction at the inner surface 27a of the hole 27A. . Therefore, light that can avoid total reflection at the interface between the substrate 21 and the anode 22 and the interface between the substrate 21 and the air is increased, and the light extraction efficiency is improved. That is, the light extraction efficiency is improved by having the configuration including the inner side surface 27a of the hole 27A.
  • the light CQ1 is light traveling toward the substrate side in a direction perpendicular to the substrate.
  • the light passes through the anode 22 and the substrate 21 without being refracted at the interface between the organic layer 23 and the anode 22 and the interface between the anode 22 and the substrate 21 and is taken out to the outside.
  • the light CQ2 is refracted toward the substrate 21 at the inner surface 27a of the hole 27A, refracted at the interface between the organic layer 23 and the anode 22, and can be extracted outside through the anode 22 and the substrate 21.
  • the light CQ3 is refracted at the inner surface 27a of the hole 27A toward the substrate 21 and the incident angle of the waveguide mode light on the substrate 21 is changed to a small angle, and is refracted at the interface between the organic layer 23 and the anode 22. Then, it can be taken out through the anode 22 and the substrate 21.
  • FIG. 4 is a schematic cross-sectional view for explaining an example of the organic EL element according to the fourth embodiment of the present invention.
  • An organic EL device 40 according to the fourth embodiment of the present invention includes, on a substrate 31, an anode 32, an organic layer 33 including a light emitting layer 3 made of an organic EL material, and a cathode 34 in this order. 34 is provided with a low refractive index layer 35 and a metal layer 36 on the opposite side of the organic layer 33.
  • the organic layer 33 includes an organic thick film layer 18 having a thickness of 10 nm to 300 nm between the light emitting layer 3 and the cathode 34.
  • the distance between the light emitting layer 3 and the metal layer 36 is 100 nm or more and 400 nm or less.
  • the refractive index of the low refractive index layer 35 is lower than the refractive index of the organic layer 33.
  • a dielectric layer 37 having a refractive index lower than that of the organic layer 33 and having a plurality of holes 37A is provided.
  • the organic layer 33 has at least a hole inner surface covering portion 33a that covers the inner surface 37a of the hole 37A.
  • the anode 32 includes an anode hole portion 32A that communicates with the hole portion 37A, and the organic layer further includes an anode hole inner surface covering portion 33b that covers the inner surface 32a of the anode hole portion 32A.
  • the organic layer 33 further has a layered portion 33 c disposed between the dielectric layer 37 and the hole inner surface covering portion 33 a and the cathode 34.
  • the layered portion 33 c includes the light emitting layer 3 and the organic thick film layer 18.
  • the organic layer 33 shown in FIG. 4 further includes a layer 19 having a function of transporting at least holes, such as a hole transport layer and a hole injection layer, closer to the anode side than the light emitting layer 3.
  • the hole inner surface covering portion and the anode hole inner surface covering portion may be constituted by a part of the layers constituting the organic layer.
  • the shape of the hole and the anode hole is not particularly limited as long as it has an effect of refracting light toward the substrate on the inner surface thereof. From the viewpoint of refracting light in the organic layer 33 more vertically, a shape in which the hole top area on the cathode 34 side is smaller than the hole bottom area on the substrate 31 side is preferable. From the viewpoint of extracting light rays such as BR1 straight up to the substrate without being refracted, a shape in which the hole bottom area on the substrate 31 side is smaller than the hole upper area on the cathode 34 side is preferable.
  • the area of the bottom surface of the hole is as small as possible.
  • those inner side surfaces are arranged perpendicular to the substrate surface, but such a configuration is not necessary.
  • the angle between the inner surface of the anode hole and the inner surface of the hole with respect to the substrate surface is preferably 30 ° or more, more preferably 45 ° or more, and even more preferably 60 ° or more. Further, a reverse taper may be used (the bottom surface of the hole on the substrate 31 side is larger than the top surface of the hole on the light emitting layer 3 side).
  • the anode 32 has a plurality of anode hole portions 32A.
  • the inner side surface 32a of the anode hole portion 32A is covered with an organic layer 33 (anode hole inner side surface covering portion 33b).
  • the upper surface of the anode 32 is covered with a dielectric layer 37.
  • the anode hole inner side surface covering portion 33b covers the inner side surface 32a, the anode hole portion 32A may be filled or partially filled.
  • the dielectric layer 37 has a refractive index lower than that of the organic layer and includes a plurality of holes 37A.
  • the inner side surface 37a of the hole 37A is covered with an organic layer 33 (inner hole side surface covering portion 33a). As long as the hole inner surface covering portion 33a covers the inner surface 37a, the hole inner surface covering portion 33a may be filled with the hole portion 37A or may be partially filled.
  • the organic layer 33 includes a light emitting layer 3 made of an organic EL material, and includes an organic thick film layer 18 having a thickness of 10 nm to 300 nm between the light emitting layer 3 and the cathode 32, and the light emitting layer 3 and the metal
  • the distance between the layers 36 is 100 nm or more and 400 nm or less.
  • the organic layer 33 includes a hole inner surface covering portion 33a that covers the inner surface 37a of the hole portion 37A, an anode hole inner surface covering portion 33b that covers the inner surface of the anode hole portion 32A, the dielectric layer 37, and the It has a layered portion 33 c disposed between the hole inner surface covering portion 33 a and the cathode 34.
  • the effect of the organic EL element of this embodiment is typically demonstrated using FIG.
  • the light propagation method indicated by the arrows in FIG. 4 is schematically shown in order to easily understand the principle of the effect.
  • the organic thick film layer 18 has a thickness of 10 nm or more, and the distance between the light emitting layer 3 and the cathode 34 is large, so that the energy transfer is difficult, and the SPP mode light The occurrence itself is suppressed.
  • the propagation method of the light indicated by the arrows in FIG. 4 is used in order to easily understand how the generated SPP mode light is extracted by the characteristic configuration of this embodiment and the principle of its effect. It is shown schematically.
  • the light traveling toward the cathode 34 is incident at the interface between the cathode 34 and the low refractive index layer 35 at an incident angle greater than the critical angle ( (Arrow AR1) When totally reflected (Arrow AR1r), an evanescent wave (Arrow AR2) is generated in the low refractive index layer 35.
  • the generated evanescent wave swells to the interface between the metal layer 36 and the low refractive index layer 35, and the SPP (arrow AR3) is excited.
  • the excited SPP is radiated to the cathode 34 at a predetermined angle (arrow AR5) via resonance with the evanescent wave (arrow AR4), and can be extracted to the organic layer 33 as guided mode light.
  • a light emission point (or light emission point) ARi indicates a light emission point at a position overlapping with the hole 37A in plan view (hereinafter, light emission at this point may be referred to as “in light emission”).
  • the light emission point ARo indicates a light emission point at a position overlapping the dielectric layer 37 in plan view (hereinafter, light emission at this point may be referred to as “out light emission”).
  • the light emission point Ae indicates light emission at a boundary position between “in light emission” and “out light emission” (hereinafter, light emission at this point may be referred to as “in-out edge light emission”).
  • the refracted light passes through the dielectric layer 37, further refracts at the interface between the dielectric layer 37 and the anode 32, travels through the anode 32, refracts at the interface between the anode 32 and the substrate 31, and then enters the substrate 31. Can be taken out through.
  • the incident angle to the substrate 31 is small due to refraction at the interface between the organic layer 33a and the dielectric layer 37 (inner side surface 37a of the hole 37A). Change to angle. In a configuration without this interface (inner surface 37a), total reflection may occur at the interface between the substrate 31 and the anode 32 and the interface between the substrate 31 and the air.
  • the incident angle of the propagating light in the organic layer to the substrate 31 changes to a small angle due to refraction at the inner side surface 37a of the hole 37A. Therefore, the light that can avoid total reflection increases and the light extraction efficiency is improved. That is, the light extraction efficiency is improved by having the configuration including the inner side surface 37a of the hole portion 37A.
  • the current density is highest near the shortest distance between the cathode 34 and the anode 32, and the amount of light emission is increased.
  • the light emission at the CRl and CRr points of the light emitting layer included in the organic layer 33 schematically shows the light emission at the point where the light emission amount is large.
  • the light CR1 is light traveling toward the substrate side in a direction perpendicular to the substrate. Therefore, the light advances through the substrate 31 without being refracted at the interface between the organic layer 33 and the substrate 31 and is taken out to the outside.
  • the light CR2 is refracted toward the substrate 31 at the inner surface 37a of the hole 37A.
  • the refracted light passes through the dielectric layer 37, refracts at the interface between the dielectric layer 37 and the anode 32, travels through the anode 32, refracts at the interface between the anode 32 and the substrate 31, and then passes through the substrate 31. It can be taken out through.
  • the incident angle to the substrate 31 is small due to refraction at the interface between the organic layer 33 and the dielectric layer 37 (the inner surface 37a of the hole 37A). Change to angle.
  • FIG. 5 is a schematic cross-sectional view for explaining an example of the organic EL element according to the fifth embodiment of the present invention.
  • An organic EL device 50 according to the fifth embodiment of the present invention includes, on a substrate 41, an anode 42, an organic layer 43 including a light emitting layer 3 made of an organic EL material, and a cathode 44 in this order. 44, a low refractive index layer 45 and a metal layer 46 are provided in this order on the side opposite to the organic layer 43.
  • the organic layer 43 includes an organic thick film layer 18 having a thickness of 10 nm to 300 nm between the light emitting layer 3 and the cathode 44.
  • the distance between the light emitting layer 3 and the metal layer 46 is not less than 100 nm and not more than 400 nm.
  • the refractive index of the low refractive index layer 45 is lower than the refractive index of the organic layer.
  • the anode 42 includes a plurality of anode hole portions 42A (see FIG. 13E) whose inner side surface 42a is covered with a dielectric layer 47 having a refractive index lower than that of the anode 42. 5 further includes a layer 19 having a function of transporting at least holes, such as a hole transport layer and a hole injection layer, closer to the anode side than the light emitting layer 3.
  • the shape of the anode hole is not particularly limited as long as it has an effect of refracting light toward the substrate on the inner surface. From the viewpoint of refracting the light in the organic layer 43 more vertically, a shape in which the bottom area on the cathode 44 side is larger than the bottom area on the substrate 41 side is preferable. From the viewpoint of extracting light rays such as B2 straight up to the substrate without being refracted, a shape having a larger area on the substrate 41 side than a bottom area on the cathode 44 side is preferable. From the viewpoint of strongly diffracting the light in the organic layer 43 and taking it out with a smaller propagation distance, a shape having as large a bottom surface area as possible is preferable. In order not to increase the sheet resistance of the anode, the bottom areas of the holes on the substrate 41 side and the cathode 44 side should be as small as possible.
  • the inner side surface 42 a of the anode hole is configured to be arranged perpendicular to the substrate surface, but is not limited to this configuration.
  • the angle of the inner surface of the anode hole with respect to the substrate surface is preferably 30 ° or more, more preferably 45 ° or more, and still more preferably 60 ° or more. Further, it may be reverse tapered (the bottom surface of the hole on the substrate 41 side is larger than the top surface of the hole on the light emitting layer 3 side).
  • the inner side surface 42a of the anode hole By setting the inner side surface 42a of the anode hole to such an angle, the light traveling from the light emitting position toward the anode side and the light re-radiated from the SPP mode light to the organic layer 43 are incident on the inner side surface 42a of the anode hole from the outside. Incident light is refracted to the substrate side, and is taken out from the outer surface of the substrate.
  • the anode 42 includes a plurality of anode holes 42A (see FIG. 13 (e)).
  • the inner side surface 42a of the anode hole portion 42A is covered with a dielectric layer 47 having a refractive index lower than that of the anode 42.
  • the dielectric layer 47 covers the inner side surface 42a, the anode layer 42A may be filled or may be partially filled.
  • the dielectric layer 47 covers the inner side surface 42a of the anode hole 42A of the anode 42 and is made of a material having a refractive index lower than that of the anode 42.
  • the reason why the dielectric layer 47 has such a configuration and material is that light incident on the inner surface 42a of the anode hole portion 42A is refracted toward the substrate 41 at this interface.
  • the organic layer 43 includes the light emitting layer 3 made of an organic EL material, and includes the organic thick film layer 18 having a thickness of 10 nm to 300 nm between the light emitting layer 3 and the cathode 42, and the light emitting layer 3 and the metal
  • the distance between the layers 46 is 100 nm or more and 400 nm or less.
  • the effect of the organic EL element of this embodiment is typically demonstrated using FIG.
  • the light propagation method indicated by the arrows in FIG. 5 is schematically shown in order to easily understand the principle of the effect.
  • the organic thick film layer 18 has a thickness of 10 nm or more, and the distance between the light emitting layer 3 and the cathode 44 is large. The occurrence itself is suppressed.
  • the propagation method of the light indicated by the arrows in FIG. 5 is used in order to easily understand how the generated SPP mode light is extracted by the characteristic configuration of this embodiment and the principle of its effect. It is shown schematically.
  • the light traveling toward the cathode 44 is incident at the interface between the cathode 44 and the low refractive index layer 45 at a large incident angle greater than the critical angle ( Arrow AS1)
  • an evanescent wave (arrow AS2) is generated in the low refractive index layer 45.
  • the generated evanescent wave squeezes out to the interface between the metal layer 46 and the low refractive index layer 45, and the SPP (arrow AS3) is excited.
  • the excited SPP is radiated to the cathode 44 at a predetermined angle (arrow AS5) through resonance with the evanescent wave (arrow AS4), and can be extracted to the organic layer 43 as guided mode light.
  • a light emission point (or light emission location) ASi indicates a light emission point at a position overlapping the electrode in plan view (hereinafter, light emission at this point may be referred to as “in light emission”).
  • the light emission point ASo indicates a light emission point at a position overlapping the electrode in plan view (hereinafter, light emission at this point may be referred to as “out light emission”).
  • the light emission point ASe indicates light emission at the boundary position between “in light emission” and “out light emission” (hereinafter, light emission at this point may be referred to as “in-out edge light emission”).
  • the light extracted from the cathode side structure (cathode 44, low refractive index layer 45, metal layer 46) to the BS point of the low refractive index layer 45 propagates like BS1 and is extracted to the substrate 41 depending on the extraction angle. . That is, the light BS1 (guided mode light) traveling through the organic layer 43 from the BS point is refracted at the interface between the organic layer 43 and the anode 42, passes through the anode 42, and passes between the anode 42 and the dielectric layer 47. The light is refracted at the interface (the inner side surface 42a of the anode hole portion 42A). The refracted light can be further refracted at the interface between the dielectric layer 47 and the substrate 41 and then taken out through the substrate 41.
  • the angle of incidence on the substrate 41 is small due to refraction at the interface between the dielectric layer 47 and the anode 42 (the inner side surface 42a of the anode hole portion 42A). Changes to. Light incident at an angle greater than the critical angle is totally reflected at the interface between the substrate (for example, glass) and air, but the incident angle on the substrate 41 is changed to a small angle by refraction at the inner surface 42a. Therefore, the light that can avoid total reflection at the interface between the substrate and air is increased, and the light extraction efficiency is improved. That is, the light extraction efficiency is improved by having the configuration including the inner side surface 42a of the anode hole portion 42A.
  • the light CS1 is light traveling toward the substrate side perpendicular to the substrate. Therefore, the light passes through the anode 42 and the substrate 41 without being refracted at the interface between the organic layer 43 and the anode 42 and the interface between the anode 42 and the substrate 41 and is taken out to the outside.
  • the light CS2 is refracted at the interface between the organic layer 43 and the anode 42, enters the anode 42, passes through the anode 42, and is transmitted at the interface between the anode 42 and the dielectric layer 47 (the inner side surface 42a of the anode hole portion 42A). Refract.
  • the refracted light can be further refracted at the interface between the anode 42 and the substrate 41 and then taken out through the substrate 41.
  • the angle of incidence on the substrate 41 is small due to refraction at the interface between the dielectric layer 47 and the anode 42 (the inner side surface 42a of the anode hole portion 42A). Changes to. Light incident at an angle greater than the critical angle is totally reflected at the interface between the substrate (for example, glass) and air, but the incident angle on the substrate 41 is changed to a small angle by refraction at the inner side surface 42a. Therefore, the light that can avoid total reflection at the interface between the substrate and air is increased, and the light extraction efficiency is improved. That is, the light extraction efficiency is improved by having the configuration including the inner side surface 42a of the anode hole portion 42A.
  • FIG. 6 is a schematic cross-sectional view for explaining an example of the organic EL element according to the sixth embodiment of the present invention.
  • An organic EL device 60 according to the sixth embodiment of the present invention includes, on a substrate 51, an anode 52, an organic layer 53 including a light emitting layer made of an organic EL material, and a cathode 54 in this order.
  • the low refractive index layer 55 and the metal layer 56 are sequentially provided on the side opposite to the organic layer 53.
  • the organic layer 53 includes an organic thick film layer 18 having a thickness of 10 nm to 300 nm between the light emitting layer 3 and the cathode 54.
  • the distance between the light emitting layer 3 and the metal layer 56 is not less than 100 nm and not more than 400 nm.
  • the refractive index of the low refractive index layer 55 is lower than the refractive index of the organic layer 53.
  • the anode 52 includes a plurality of anode hole portions 52A (see FIG. 14E).
  • the organic layer 53 is disposed between an anode hole inner surface covering portion 53a that covers the inner surface 52a of the anode hole 52A, and between the anode 52 and the anode hole inner surface covering portion 53a and the cathode 54. And a layered portion 53b.
  • the 6 includes a layer 19 having a function of transporting at least holes, such as a hole transport layer and a hole injection layer, on the anode side from the light emitting layer 3.
  • the anode hole inner side surface covering portion 53 a is composed of the layer 19, the anode hole inner side surface covering portion 53 a may be constituted by a part of the layers constituting the organic layer 53.
  • the shape of the anode hole 52A is not particularly limited as long as it has an effect of refracting light toward the substrate on the inner surface thereof. From the viewpoint of refracting light in the organic layer 53 more vertically, a shape in which the bottom area on the cathode 54 side is smaller than the bottom area on the substrate 51 side is preferable. From the viewpoint of extracting light emitted obliquely from the SPP to the organic layer 53 to the substrate straight without refraction, a shape having a smaller area on the substrate 51 side than a bottom area on the cathode 54 side is preferable. From the viewpoint of strongly diffracting the light in the organic layer 53 and extracting it with a smaller propagation distance, a shape having the smallest possible bottom area is preferable.
  • the inner side surface is configured to be arranged perpendicular to the substrate surface, but such a configuration is not necessary.
  • FIG. 6 shows an example in which the refractive index of the organic layer 53 is lower than the refractive index of the anode 52, the present invention is not limited to this. Even in the reverse case, the direction of the light beam can be changed to a direction where the incident angle to the substrate is small, so that the light extraction efficiency can be improved. For example, when light travels from the organic layer 53 into the anode 52 through the anode hole 52A, the incident angle on the substrate 51 is changed to a small angle due to refraction, so that the light extraction efficiency is improved.
  • the angle of the inner surface 52a of the anode hole 52A with respect to the substrate surface is preferably 30 ° or more, more preferably 45 ° or more, and still more preferably 60 ° or more. Further, it may be reverse tapered (the bottom surface of the hole on the substrate 51 side is larger than the top surface of the hole on the light emitting layer 3 side).
  • the inner side surface 52a of the anode hole 52A By setting the inner side surface 52a of the anode hole 52A to such an angle, the light directed from the light emitting position toward the anode side and the light re-radiated from the SPP mode light into the organic layer 53 are disposed on the inner side surface 52a of the anode hole 52A. Is incident from the outside and refracted toward the substrate side, and is taken out from the outer surface of the substrate.
  • the effect of the organic EL element of this embodiment is typically demonstrated using FIG.
  • the light propagation method indicated by the arrows in FIG. 6 is schematically shown in order to easily understand the principle of the effect.
  • the organic thick film layer 18 has a thickness of 10 nm or more, and the distance between the light emitting layer 3 and the cathode 54 is large. The occurrence itself is suppressed.
  • the propagation method of the light indicated by the arrows in FIG. 5 is used in order to easily understand how the generated SPP mode light is extracted by the characteristic configuration of this embodiment and the principle of its effect. It is shown schematically.
  • the light traveling toward the cathode 54 is incident at the interface between the cathode 54 and the low refractive index layer 55 at an incident angle greater than the critical angle.
  • Arrow AT1r When totally reflected (Arrow AT1r), an evanescent wave (Arrow AT2) is generated in the low refractive index layer 55. The generated evanescent wave swells to the interface between the metal layer 56 and the low refractive index layer 55, and the SPP (arrow AT3) is excited.
  • a light emission point (or light emission location) ATi indicates a light emission point at a position overlapping the anode 52 in plan view (hereinafter, light emission at this point may be referred to as “in light emission”).
  • the light emission point Ao indicates a light emission point at a position between the adjacent anodes 52 in plan view (hereinafter, light emission at this point may be referred to as “out light emission”).
  • the light emission point Ae indicates light emission at a boundary position between “in light emission” and “out light emission” (hereinafter, light emission at this point may be referred to as “in-out edge light emission”).
  • in-out edge light emission For “out emission” and “in-out edge emission”, the arrow indicating total reflection at the interface between the cathode 54 and the low refractive index layer 55 is omitted.
  • the propagation of light after SPP (arrow AT3) excitation is “ This is similar to the case of “in light emission”. Since the current flows between the cathode and the anode, the light emission point ATi is located in a route having a higher current density than the light emission point ATo, so that “in light emission” has a larger light emission amount than “out light emission”.
  • the light extracted from the cathode side structure (cathode 55, low refractive index layer 55, metal layer 56) to the BT point of the organic layer 53 propagates like BT1 and is extracted to the substrate 51. That is, the light BT1 traveling through the organic layer 53 from the BT point is refracted toward the substrate 51 at the interface between the organic layer 53a and the anode 52 (the inner surface 52a of the anode hole portion 52A). The refracted light passes through the anode 52 and is refracted at the interface between the anode 52 and the substrate 51, and then can be extracted outside through the substrate 51.
  • the angle of incidence on the substrate 51 is small (substrate) due to refraction at the interface between the organic layer 53a and the anode 52 (inner side surface 52a of the anode hole 52A). 51) (an angle closer to the vertical direction).
  • Light incident at an angle greater than the critical angle at the interface between the anode 52 and the substrate (for example, glass) 51 and at the interface between the substrate 51 and air is totally reflected, but at the inner surface 52a of the anode hole 52A.
  • the incident angle to the substrate 1 is changed to a small angle by refraction. Therefore, the light that can avoid the total reflection increases and the light extraction efficiency is improved. That is, the light extraction efficiency is improved by having the configuration including the inner side surface 52a of the anode hole 52A.
  • the light CT1 is light that travels to the substrate side perpendicular to the substrate, and the interface between the organic layer 53 and the anode 52 and the anode 52 and substrate 51 Without being refracted even at the interface, the anode 52 and the substrate 51 are taken out and taken out to the outside.
  • the light CT2 is refracted at the interface between the organic layer 53 and the anode 52, enters the anode 52, passes through the anode 52, and is refracted at the interface between the anode 52 and the organic layer 53a (the inner surface 52a of the anode hole 52A). To do.
  • the refracted light can be refracted at the interface between the anode 52 and the substrate 51 and then extracted outside through the substrate 51.
  • the incident angle on the substrate 51 changes to a small angle due to refraction at the interface between the organic layer 53a and the anode 52 (the inner side surface 52a of the anode hole 52A).
  • Light incident at an angle greater than the critical angle is totally reflected at the interface between the substrate (for example, glass) and air, but the incident angle on the substrate 51 is changed to a small angle by refraction at the inner surface 52a. Therefore, the light that can avoid total reflection at the interface between the substrate and air is increased, and the light extraction efficiency is improved.
  • the light extraction efficiency is improved by having the configuration including the inner side surface 52a of the anode hole 52A. Similar effects can be obtained with the light CT3. As described above, since the light emitted from the organic layer 53 travels in all directions, there is naturally light traveling to the cathode side structure, etc. Only some of them are shown schematically.
  • FIG. 7 is a schematic cross-sectional view for explaining an example of the organic EL element according to the seventh embodiment of the present invention.
  • An organic EL element 70 according to the seventh embodiment of the present invention includes a dielectric layer 67, an anode 62, an organic layer 63 including a light emitting layer 3 made of an organic EL material, and a cathode 64 on a substrate 61.
  • a low refractive index layer 65 and a metal layer 66 are sequentially provided on the opposite side of the cathode 64 from the organic layer 63.
  • the organic layer 63 includes an organic thick film layer 18 having a thickness of 10 nm to 300 nm between the light emitting layer 3 and the cathode 64.
  • the distance between the light emitting layer 3 and the metal layer 66 is 100 nm or more and 400 nm or less.
  • the refractive index of the low refractive index layer 65 is lower than the refractive index of the organic layer 63.
  • the dielectric layer 67 has a refractive index lower than that of the anode 62 and is formed in a pattern having an opening 67A so that the substrate 61 is exposed.
  • the anode 62 and the organic layer 63 are formed so as to follow the pattern of the dielectric layer 67.
  • the organic layer 63 shown in FIG. 7 further includes a layer 19 having a function of transporting at least holes, such as a hole transport layer and a hole injection layer, closer to the anode side than the light emitting layer 3.
  • the inner surface 67a of the opening 67A is arranged perpendicular to the substrate surface, but it is not necessary to have such a configuration.
  • the angle of the inner surface 67a of the opening 67A with respect to the substrate surface is preferably 30 ° or more, more preferably 45 ° or more, and even more preferably 60 ° or more. Further, it may be reverse tapered (the bottom surface of the hole on the substrate 61 side is larger than the top surface of the hole on the light emitting layer 3 side).
  • the inner side surface 67a of the opening 67A By setting the inner side surface 67a of the opening 67A to such an angle, the light traveling from the light emitting position toward the anode side and the light re-radiated from the SPP mode light into the organic layer 63 are incident on the inner side surface 67a of the opening from the outside. Incident light is refracted to the substrate side, and is taken out from the outer surface of the substrate.
  • the light traveling toward the cathode 64 is incident at an angle greater than the critical angle at the interface between the cathode 64 and the low refractive index layer 65 ( Arrow AU1)
  • an evanescent wave (arrow AU2) is generated in the low refractive index layer 65.
  • the generated evanescent wave squeezes out to the interface between the metal layer 66 and the low refractive index layer 65, and the SPP (arrow AU3) is excited.
  • the excited SPP mode light is radiated to the cathode 64 (arrow AU5) at a predetermined angle via resonance with the evanescent wave (arrow AU4), and can be extracted to the organic layer 63.
  • a light emission point (or light emission location) AUi indicates a light emission point at a position overlapping the convex portion 62A of the anode 62 in plan view (hereinafter, light emission at this point is referred to as “in light emission”). is there.).
  • the light emitting point AUo indicates a light emitting point between adjacent convex portions 62A (recessed portion 62B) in plan view (hereinafter, light emission at this point may be referred to as “out light emission”).
  • the light emission point AUe indicates light emission at the boundary between “in light emission” and “out light emission” (hereinafter, light emission at this point may be referred to as “in-out edge light emission”).
  • the light extracted from the cathode side structure (cathode 64, low refractive index layer 65, metal layer 66) to the BU point of the low refractive index layer 65 propagates like BU1 and is extracted to the substrate 61 depending on the angle at which it is extracted. . That is, the light BU1 (waveguide mode light) traveling through the organic layer 3 from the BU point is refracted at the interface between the organic layer 63 and the anode 62, is transmitted through the anode 62, and is formed between the recess 62B and the dielectric layer 67. The light is refracted toward the substrate 61 at the interface (the inner surface 67a of the opening 67A of the dielectric layer 67).
  • the refracted light passes through the dielectric layer 67, is refracted at the interface between the dielectric layer 67 and the substrate 61, and then can be extracted outside through the substrate 61.
  • the light BU1 travels from the recess 62B to the dielectric layer 67, it is incident on the substrate 61 due to refraction at the interface between the recess 62B and the dielectric layer 67 (the inner surface 67a of the opening 67A of the dielectric layer 67).
  • the corner changes to a smaller angle.
  • the light extraction efficiency is improved by having a configuration including the interface between the recess 62B and the dielectric layer 67 (the inner surface 67a of the opening 67A of the dielectric layer 67).
  • the light CU1 is light traveling toward the substrate in a direction perpendicular to the substrate. It proceeds through the substrate 61 without being refracted at the interface with the substrate 61 and is taken out to the outside.
  • the light CU2 is refracted at the interface between the recess 62B and the dielectric layer 67 (the inner surface 67a of the opening 67A of the dielectric layer 67).
  • the refracted light passes through the dielectric layer 67, is refracted at the interface between the dielectric layer 67 and the substrate 61, and can be taken out through the substrate 61.
  • the light CU2 travels from the anode 62 to the dielectric layer 67, it is incident on the substrate 61 due to refraction at the interface between the recess 62B and the dielectric layer 67 (the inner surface 67a of the opening 67A of the dielectric layer 67).
  • the angle changes to a smaller angle.
  • Light incident at an angle greater than the critical angle is totally reflected at the interface between the anode 2 and the substrate (for example, glass) 61 and the interface between the substrate 61 and air. Due to refraction at the inner surface 67a) of the opening 67A of the dielectric layer 67, the angle of incidence on the substrate 61 changes to a small angle. Therefore, the light that can avoid the total reflection increases and the light extraction efficiency is improved. Similar effects can be obtained for the light CU3.
  • FIG. 15 is a schematic cross-sectional view for explaining an example of the organic EL element according to the eighth embodiment of the present invention.
  • An organic EL element 80 according to an eighth embodiment of the present invention includes, on a substrate 81, an anode 82, an organic layer 83 including a light emitting layer 3 made of an organic EL material, and a cathode 84 in this order.
  • 84 is provided with a low refractive index layer 85 and a metal layer 86 in this order on the side opposite to the organic layer 83.
  • the organic layer 83 includes an organic thick film layer 18 having a thickness of 10 nm or more and 300 nm or less between the light emitting layer 3 and the cathode 84.
  • the distance between the light emitting layer 3 and the metal layer 86 is 100 nm or more and 400 nm or less.
  • a high refractive index layer 87 provided with a plurality of convex portions 87a having a triangular shape whose apex is directed to the substrate 81 side in a sectional view.
  • the structure including a plurality of convex portions 87a having a triangular shape is an example of a sawtooth-shaped structure.
  • the cross-sectional shape in a plane perpendicular to the element surface has a triangular shape.
  • the plurality of convex portions constituting the sawtooth structure is not limited to a triangular convex portion, and for example, the cross section of the convex portion may be a trapezoidal shape, a multistage shape, or the like.
  • the high refractive index layer 87 may be in contact with the anode 82 or may be configured such that another layer is interposed between the high refractive index layer 87 and the anode 82.
  • the 15 includes a layered portion 87b on the anode side, and a plurality of convex portions 87a having a triangular shape with the apex facing the substrate side in a cross-sectional view on the layered portion 87b. is there.
  • the high refractive index layer 87 which is an example of the anode side structure is made of a material having a higher refractive index than the material of the layer adjacent to the substrate 81 side.
  • the layer adjacent to the substrate 81 side is the substrate 81.
  • ⁇ h is the dielectric constant of the high refractive index layer 87. Therefore, the propagation angle ⁇ h in the high refractive index layer 87 of the SPP taken out to the high refractive index layer 87 after being re-radiated into the organic layer 83 by the Otto type arrangement can be expressed by the following equation. . That propagation angle theta h, the dielectric constant of the high-refractive index layer 87 epsilon h, the real part epsilon 1 of the dielectric constant of the metal layer 86 is a value determined from the dielectric constant epsilon 2 of the low refractive index layer 85.
  • FIG. 16 is a cross-sectional schematic diagram for demonstrating an example of the organic EL element which concerns on the 9th Embodiment of this invention.
  • An organic EL device 90 according to a ninth embodiment of the present invention includes, on a substrate 91, an anode 92, an organic layer 93 including a light emitting layer 3 made of an organic EL material, and a cathode 94 in this order.
  • a low refractive index layer 95 and a metal layer 96 are sequentially provided on the side opposite to the organic layer 93.
  • the organic layer 93 includes an organic thick film layer 18 having a thickness of 10 nm to 300 nm between the light emitting layer 3 and the cathode 94.
  • the distance between the light emitting layer 3 and the metal layer 96 is 100 nm or more and 400 nm or less.
  • a transmission type diffraction grating 98 is provided between the anode 92 and the substrate 91.
  • the diffraction grating 98 may be arranged at any position between the outer surface 91 ⁇ / b> A of the substrate 91 and the organic layer 93. In this embodiment, a structure is formed between the substrate 91 and the anode 92.
  • Each of the grating part 98a and the grating part 98b constituting the diffraction grating 98 is made of a dielectric material having a different refractive index.
  • the diffraction grating 98 diffracts toward the normal to the surface of the substrate 91 (changes the incident angle of the waveguide mode light to a small angle), thereby reducing the proportion of light that causes total reflection and improving light extraction efficiency.
  • FIG. 17 is a schematic cross-sectional view for explaining an example of the organic EL element according to the tenth embodiment of the present invention.
  • An organic EL device 300 according to a tenth embodiment of the present invention includes, on a substrate 301, an anode 302, an organic layer 303 including a light emitting layer 3 made of an organic EL material, and a cathode 304 in this order.
  • a low refractive index layer 305 and a metal layer 306 are sequentially provided on the side of 304 opposite to the organic layer 303.
  • the organic layer 303 includes an organic thick film layer 18 having a thickness of 10 nm or more and 300 nm or less between the light emitting layer 3 and the cathode 304.
  • the distance between the light emitting layer 3 and the metal layer 306 is 100 nm or more and 400 nm or less.
  • a lens structure 308 protruding toward the substrate is provided between the substrate 301 and the anode 302.
  • the lens structure 308 may be arranged at any position between the outer surface 301 ⁇ / b> A of the substrate 301 and the organic layer 303. This embodiment is configured to be provided between the substrate 301 and the anode 302.
  • the lens structure 308 can refract light incident on the lens structure 308 from the cathode 304 side so as to be incident from a direction nearer perpendicular to the substrate, and any one between the lens structure 308 and the outer surface 301A.
  • the ratio of light that causes total reflection at the interface is reduced, and the light extraction efficiency is improved.
  • FIG. 8 is a diagram illustrating an example of an image display device including the organic EL element.
  • the image display device 100 shown in FIG. 8 is a so-called passive matrix image display device.
  • an anode wiring 104, an anode auxiliary wiring 106, a cathode wiring 108, an insulating film 110, a cathode partition 112, a sealing plate 116, and a sealing material 118 are provided.
  • a plurality of anode wirings 104 are formed on the substrate 1 of the organic EL element 10.
  • the anode wirings 104 are arranged in parallel at a constant interval.
  • the anode wiring 104 is made of a transparent conductive film, and for example, ITO (Indium Tin Oxide) can be used.
  • the thickness of the anode wiring 104 can be set to 100 nm to 150 nm, for example.
  • An anode auxiliary wiring 106 is formed on the end of each anode wiring 104.
  • the anode auxiliary wiring 106 is electrically connected to the anode wiring 104.
  • the anode auxiliary wiring 106 functions as a terminal for connecting to the external wiring on the end portion side of the substrate 1, and the drive circuit (not shown) provided outside via the anode auxiliary wiring 106.
  • a current can be supplied to the anode wiring 104.
  • the anode auxiliary wiring 106 is made of a metal film having a thickness of 500 nm to 600 nm, for example.
  • a plurality of cathode wirings 108 are provided on the organic EL element 10.
  • the plurality of cathode wirings 108 are arranged so as to be parallel to each other and orthogonal to the anode wiring 104.
  • Al or an Al alloy can be used for the cathode wiring 108.
  • the thickness of the cathode wiring 108 is, for example, 100 nm to 150 nm.
  • a cathode auxiliary wiring (not shown) is provided at the end of the cathode wiring 108, similarly to the anode auxiliary wiring 106 for the anode wiring 104, and is electrically connected to the cathode wiring 108. Therefore, a current can flow between the cathode wiring 108 and the cathode auxiliary wiring.
  • an insulating film 110 is formed on the substrate 1 so as to cover the anode wiring 104.
  • a rectangular opening 120 is provided in the insulating film 110 so as to expose a part of the anode wiring 104.
  • the plurality of openings 120 are arranged in a matrix on the anode wiring 104.
  • the organic EL element 10 is provided between the anode wiring 104 and the cathode wiring 108. That is, each opening 120 becomes a pixel. Accordingly, a display area is formed corresponding to the opening 120.
  • the film thickness of the insulating film 110 can be, for example, 200 nm to 100 nm, and the size of the opening 120 can be, for example, 100 ⁇ m ⁇ 100 ⁇ m.
  • the organic EL element 10 is located between the anode wiring 104 and the cathode wiring 108 in the opening 120. In this case, the anode 2 of the organic EL element 10 is in contact with the anode wiring 104 and the cathode 4 is in contact with the cathode wiring 108.
  • the thickness of the organic EL element 10 can be set to, for example, 150 nm to 200 nm.
  • a plurality of cathode partition walls 112 are formed on the insulating film 110 along a direction perpendicular to the anode wiring 104.
  • the cathode partition 112 plays a role for spatially separating the plurality of cathode wirings 108 so that the wirings of the cathode wirings 108 do not conduct with each other. Accordingly, the cathode wiring 108 is disposed between the adjacent cathode partition walls 112.
  • the size of the cathode partition 112 for example, the one having a height of 2 ⁇ m to 3 ⁇ m and a width of 10 ⁇ m can be used.
  • the substrate 1 is bonded through a sealing plate 116 and a sealing material 118. Thereby, the space in which the organic EL element 10 was provided can be sealed. It is possible to prevent the organic EL element 10 from being deteriorated by moisture in the air.
  • a sealing plate 116 for example, a glass substrate having a thickness of 0.7 mm to 1.1 mm can be used.
  • a current can be supplied to the organic EL element 10 via the anode auxiliary wiring 106 and the cathode auxiliary wiring (not shown) by a driving device (not shown) to cause the light emitting layer to emit light. Then, light can be emitted from the substrate 1 through the substrate 1.
  • An image can be displayed on the image display device 100 by controlling the light emission and non-light emission of the organic EL element 10 corresponding to the above-described pixel by the control device.
  • FIG. 9 is a diagram illustrating an example of an illumination device including the organic EL element 10 described above.
  • the lighting device 200 shown in FIG. 9 includes the organic EL element 10 described above, and a terminal 202 that is installed adjacent to the substrate 1 (see FIG. 1) of the organic EL element 10 and connected to the anode 2 (see FIG. 1).
  • the terminal 203 is connected to the cathode 4 (see FIG. 1), and the lighting circuit 201 is connected to the terminal 202 and the terminal 203 to drive the organic EL element 10.
  • the lighting circuit 201 has a DC power supply (not shown) and a control circuit (not shown) inside, and supplies a current between the anode layer 2 and the cathode 4 of the organic EL element 10 through the terminal 202 and the terminal 203. Then, the organic EL element 10 is driven, the light emitting layer is caused to emit light, light is emitted from the substrate 1, and used as illumination light.
  • the light emitting layer may be made of a light emitting material that emits white light, and each of the organic EL elements 10 using light emitting materials that emit green light (G), blue light (B), and red light (R). A plurality of them may be provided so that the combined light is white.
  • the organic EL device includes an anode 2, an organic layer 103 including a light emitting layer 3 and an organic thick film layer 18 made of an organic EL material, a cathode 4, a low
  • the refractive index layer 5 and the metal layer 6 can be formed in this order.
  • the same method as the formation of the anode 12 to the metal layer 16 in the manufacturing method of the second embodiment described later can be used.
  • the method of manufacturing from the anode side has been described, it may be manufactured from the cathode side.
  • the manufacturing method of the organic EL element of the 2nd Embodiment of this invention is demonstrated with reference to FIG.
  • the formation method of the anode 12 and the dielectric layer 17 is not particularly limited.
  • a resistance heating vapor deposition method, an electron beam vapor deposition method, a sputtering method, an ion plating method, a CVD method, or the like can be used.
  • the surface treatment of the anode 12 after forming the anode 12 the performance of the overcoated layer (adhesion with the anode 12, surface smoothness, reduction of the hole injection barrier, etc.) can be improved.
  • the surface treatment includes high-frequency plasma treatment, sputtering treatment, corona treatment, UV ozone irradiation treatment, ultraviolet irradiation treatment, oxygen plasma treatment, and the like.
  • an effect similar to the surface treatment can be expected by forming an anode buffer layer (not shown).
  • anode buffer layer is applied by a wet process, spin coating, casting, micro gravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating
  • the film can be formed using a coating method such as a spray method, a spray coating method, a screen printing method, a flexographic printing method, an offset printing method, or an inkjet printing method.
  • the anode hole portion 12A and the hole portion 17A communicating with each other are formed so as to penetrate the anode 12 and the dielectric layer 17 formed in the step of FIG.
  • a method using photolithography can be used.
  • a positive resist solution is applied onto the dielectric layer 17, and the excess resist solution is removed by spin coating or the like to form a resist layer 29. To do.
  • a mask (not shown) on which a predetermined pattern for forming the anode hole portion 12A and the hole portion 17A is drawn is applied, and exposure is performed with ultraviolet rays (UV), electron beams (EB), and the like.
  • UV ultraviolet rays
  • EB electron beams
  • FIG. 10C the resist layer 29 is exposed with a predetermined pattern corresponding to the hole 17A (see FIG. 10F) (exposed portion 29a).
  • the resist layer 29a in the exposed pattern portion of the resist layer 29 is removed using a developer.
  • the surface of the dielectric layer 17 is exposed corresponding to the exposed pattern portion (FIG. 10D).
  • the portion of the dielectric layer 17 at the position of the hole 17A is etched away as shown in FIG.
  • the etching either dry etching or wet etching can be used.
  • the shape of the hole 17A can be controlled by combining isotropic etching and anisotropic etching.
  • RIE reactive ion etching
  • wet etching a method of immersing in dilute hydrochloric acid or dilute sulfuric acid can be used. By this etching, the surface of the anode 12 is exposed corresponding to the pattern.
  • FIG. 10F a resist removing solution or the like
  • FIG. 10G. 10G a resist removing solution or the like
  • the exposed portion of the anode 12 is removed using the dielectric layer 17 as a mask as shown in FIG. 10G. Etch away.
  • the etching a method similar to the method described with reference to FIG. By changing the etching conditions, the anode 12 can be selectively etched without significantly affecting the dielectric layer 17. Thereby, the surface of the substrate 11 is exposed corresponding to the pattern, and the anode hole portion 12A is formed.
  • FIG. 10F and FIG. 10G can be regarded as a process of penetrating the anode 12 and the dielectric layer 17 and forming the communicating hole 17A and anode hole 12A.
  • the exposed portion of the substrate 11 is removed by etching using a portion other than the portion where the communicating hole portion 17A and anode hole portion 12A are formed as a mask.
  • etching a method similar to the method described in FIGS. 10F and 10G can be used.
  • the substrate 11 can be selectively etched without significantly affecting the dielectric layer 17 and the anode 12.
  • the concave portion 11A communicating with the hole portion 17A and the anode hole portion 12A can be formed corresponding to the pattern.
  • the portion other than the concave portion 11A becomes the convex portion 11B. According to this method, since it is not necessary to prepare a mask separately and perform photolithography, the concave portion 11A can be formed more easily.
  • the organic layer 13 includes a hole inner surface covering portion 13a, an anode hole inner surface covering portion 13b, a concave inner surface covering portion 13c, and a layered portion 13d.
  • the organic layer 13 includes the light emitting layer 3 (see FIG. 2), an organic thick film layer 18 (see FIG. 2) of 10 nm to 300 nm and a layer 19 (see FIG.
  • a conventionally known method can be used for forming the organic layer 13 and is not particularly limited.
  • a method such as a vacuum deposition method, a spin coating method, a casting method, or an LB method can be used.
  • a cathode 14 is formed on the organic layer 13.
  • the cathode 13 can be formed by the same method as the anode 12 and is not limited.
  • a resistance heating vapor deposition method an electron beam vapor deposition method, a sputtering method, an ion plating method, a CVD method, or the like can be used.
  • a low refractive index layer 15 is formed on the cathode 14.
  • the low refractive index layer 15 can be formed by the same method as the formation of the dielectric layer 17 and is not limited. For example, a resistance heating vapor deposition method, an electron beam vapor deposition method, a sputtering method, an ion plating method, a CVD method, or the like can be used.
  • a metal layer 16 is formed on the low refractive index layer 15.
  • the formation of the metal layer 16 is not particularly limited.
  • an electron beam evaporation method, a sputtering method, an ion plating method, or a CVD method can be used.
  • the organic EL element 20 can be manufactured by the above process. After these series of steps, it is preferable to use the organic EL element 20 stably for a long period of time and to attach a protective layer and a protective cover (not shown) for protecting the organic EL element 20 from the outside.
  • a protective layer polymer compounds, metal oxides, metal fluorides, metal borides, silicon compounds such as silicon nitride and silicon oxide, and the like can be used. And these laminated bodies can also be used.
  • a glass plate, a plastic plate whose surface has been subjected to low water permeability treatment, a metal, or the like can be used.
  • the protective cover is preferably bonded to the substrate 11 with a thermosetting resin or a photocurable resin and sealed. At this time, it is preferable to use a spacer between the substrate 11 and the protective cover because a predetermined space can be maintained and the organic EL element 20 can be prevented from being damaged. If an inert gas such as nitrogen, argon, or helium is sealed in this space, it becomes easy to prevent oxidation of the upper metal layer 16. In particular, when helium is used, heat conduction is high, and thus heat generated from the organic EL element 20 when voltage is applied can be effectively transmitted to the protective cover, which is preferable. Furthermore, it becomes easy to suppress that the water
  • desiccants such as barium oxide
  • FIG. 10 (a) to 10 (e) are the same as the method for manufacturing the organic EL element of the second embodiment.
  • FIG. 11A corresponds to FIG.
  • the dielectric layer 27 is removed by etching using the remaining resist layer as a mask to form a hole 27A (FIG. 11A).
  • a hole inner surface covering portion 23a that covers the inner surface 27a of the hole 27A is formed, and the dielectric layer 27, the hole inner surface covering portion 23a, and the cathode 24 are formed.
  • the layered portion 23b disposed therebetween is formed, and the organic layer 23 including the light emitting layer made of the organic EL material is formed.
  • a method similar to the method of manufacturing the organic EL element of the second embodiment can be used.
  • a cathode 24, a low refractive index layer 25, and a metal layer 26 are sequentially formed on the organic layer 23.
  • a method similar to the method of manufacturing the organic EL element of the second embodiment can be used.
  • the method of manufacturing from the anode side has been described, but it may be manufactured from the cathode side.
  • FIG. 12A corresponds to FIG.
  • the dielectric layer 37 is removed by etching to form a hole 37A.
  • the anode hole 32A is formed using the formed dielectric layer 37 as a mask.
  • a hole inner surface covering portion 33a covering the inner surface 37a of the hole 37A and an anode hole inner surface covering portion 33b covering the inner surface of the anode hole 32A are provided.
  • a dielectric layer 37 and a layered portion 33c disposed between the hole inner side surface covering portion 33a and the cathode 34 are formed to form an organic layer 33 including a light emitting layer made of an organic EL material.
  • a method similar to the method of manufacturing the organic EL element of the second embodiment can be used.
  • a cathode 34, a low refraction layer 35, and a metal layer 36 are formed in order on the organic layer 33.
  • a method similar to the manufacturing method of the second embodiment can be used for forming these layers.
  • the method of manufacturing from the anode side has been described, but it may be manufactured from the cathode side.
  • an anode 42 is formed on a substrate 41.
  • the method for forming the anode 42 is not particularly limited, and for example, a resistance heating vapor deposition method, an electron beam vapor deposition method, a sputtering method, an ion plating method, a CVD method, or the like can be used.
  • a method using photolithography can be used to form the anode hole portion 42A.
  • a positive resist solution is applied onto the anode 42, and the excess resist solution is removed by spin coating or the like to form a resist layer 49.
  • a mask (not shown) on which a predetermined pattern for forming the anode hole 42A is drawn is placed, and exposure is performed with ultraviolet rays (UV), electron beams (EB), or the like.
  • UV ultraviolet rays
  • EB electron beams
  • FIG. 13C the resist layer 49 is exposed to a predetermined pattern corresponding to the anode hole portion 42A (exposed portion 49a).
  • the resist layer 49 in the exposed pattern portion is removed using a developer.
  • the surface of the anode 42 is exposed corresponding to the exposed pattern portion (FIG. 13D).
  • the exposed portion of the anode 42 is removed by etching to form an anode hole portion 42A.
  • a dielectric layer 47 is formed as shown in FIG. In FIG. 13F, the dielectric layer 47 is configured to fill the anode hole portion 42A and cover the inner side surface 42a of the anode hole portion 42A. However, the dielectric layer 47 is partially filled to cover the inner side surface 42a of the anode hole portion 42A. The structure to do may be sufficient. If the dielectric layer 47 covers the inner surface 42a of the anode hole 42A, the formation conditions are adjusted depending on whether the anode hole 42A is completely filled or partially filled.
  • an organic layer 43 including a light emitting layer made of an organic EL material is formed on the anode 42 and the dielectric layer 47.
  • a cathode 44 is formed on the organic layer 43.
  • the formation of the cathode 43 can be performed using the same method as the formation of the anode 42 and is not limited.
  • a resistance heating vapor deposition method an electron beam vapor deposition method, a sputtering method, an ion plating method, a CVD method, or the like can be used.
  • a low refractive index layer 45 is formed on the cathode 44.
  • the low refractive index layer 45 can be formed by the same method as the formation of the dielectric layer 47, and is not limited.
  • a resistance heating vapor deposition method, an electron beam vapor deposition method, a sputtering method, an ion plating method, a CVD method, or the like can be used.
  • a metal layer 46 is formed on the low refractive index layer 45.
  • a method similar to the manufacturing method of the second embodiment can be used.
  • the organic EL element 50 can be manufactured by the above process. In the above manufacturing method of the organic EL element, the method of manufacturing from the anode side has been described, but it may be manufactured from the cathode side.
  • the anode 52 is formed on the substrate 51.
  • a method using photolithography can be used to form the anode hole 52A.
  • FIG. 14B first, a positive resist solution is applied onto the anode 52, and the excess resist solution is removed by spin coating or the like to form a resist layer 59.
  • a mask (not shown) on which a predetermined pattern for forming the anode hole portion 52A is drawn is placed, and exposure is performed with ultraviolet rays (UV), electron beams (EB), or the like.
  • UV ultraviolet rays
  • EB electron beams
  • FIG. 14C the resist layer 59 is exposed to a predetermined pattern corresponding to the anode hole 52A.
  • the resist layer 59 in the exposed pattern portion is removed using a developer.
  • the surface of the anode 52 is exposed corresponding to the exposed pattern portion (FIG. 14D).
  • the exposed portion of the anode 52 is removed by etching using the remaining resist layer 59 as a mask to form an anode hole 52A.
  • the anode hole inner side surface covering portion 53a of the organic layer 53 fills the anode hole portion 52A and covers the inner side surface 52a of the anode hole portion 52A.
  • a configuration in which only a part is filled and the inner side surface 52a of the anode hole 52A is covered may be employed. If the anode hole inner side surface covering portion 53a covers the inner surface 52a of the anode hole portion 52A, the formation conditions are adjusted depending on whether the anode hole portion 52A is completely filled or partially filled.
  • the organic layer 53 is also formed by forming the layered portion 53b of the organic layer 53, corresponding to FIG. 14 (g). Create the structure.
  • a cathode 54 is formed on the organic layer 53.
  • a low refractive index layer 55 is formed on the cathode 54.
  • a method for forming the low refractive index layer 55 is not particularly limited. For example, a resistance heating vapor deposition method, an electron beam vapor deposition method, a sputtering method, an ion plating method, a CVD method, or the like can be used.
  • a resistance heating vapor deposition method an electron beam vapor deposition method, a sputtering method, an ion plating method, a CVD method, or the like can be used.
  • a metal layer 56 is formed on the low refractive index layer 55.
  • a method similar to the manufacturing method of the second embodiment can be used to form the organic layer 53 to the metal layer 56.
  • the organic EL element 60 can be manufactured by the above process. In the above manufacturing method of the organic EL element, the method of manufacturing from the anode side has been described, but it may be manufactured from the cathode side.
  • the manufacturing method of the organic EL element which is the 7th Embodiment of this invention is demonstrated.
  • a dielectric layer 67 having a refractive index lower than that of the anode 62 is formed on the substrate 61.
  • a pattern having openings 67A is formed in the dielectric layer 67 so that the substrate 61 is exposed.
  • the photolithography method of the second embodiment can be used.
  • the anode 62, the organic layer 63, the cathode 64, the low refractive index layer 65, and the metal layer 66 are formed so as to follow the pattern of the opening 67A.
  • the same method as in the second embodiment can be used.
  • the organic EL element 70 can be manufactured.
  • the method of manufacturing from the anode side has been described, but it may be manufactured from the cathode side.
  • a concave portion corresponding to the convex portion 87 a having a triangular cross section is formed on the substrate 81.
  • the forming method is not particularly limited, and machining such as cutting and polishing, laser processing, and the like can be used.
  • the high refractive index layer 87 is formed so as to fill the formed recess.
  • Forming methods include a method of applying and converting a spin-on dielectric, a method of applying and curing a curable resin, and the like.
  • As a coating method various processes such as spin coating, bar coating, slit coating, die coating, and spray coating can be used.
  • the anode 82, the organic layer 83, the cathode 84, the low refractive index layer 85, and the metal layer 86 are formed on the high refractive index layer 87.
  • the same method as in the second embodiment can be used.
  • the organic EL element 80 can be manufactured by the above process. In the above manufacturing method of the organic EL element, the method of manufacturing from the anode side has been described, but it may be manufactured from the cathode side.
  • the manufacturing method of the organic EL element which is the 9th Embodiment of this invention is demonstrated.
  • the diffraction grating 98 is formed on the substrate 91.
  • a method for forming the diffraction grating 98 a method in which the hole forming method by a layer forming method, a photolithography method, or the like, similar to the anode and the dielectric layer in the method for manufacturing the organic EL element of the fifth embodiment, is combined. Can be used.
  • an anode 92, an organic layer 93, a cathode 94, a low refractive index layer 95, and a metal layer 96 are formed on the formed diffraction grating 98.
  • the same method as in the second embodiment can be used.
  • the organic EL element 90 can be manufactured.
  • the method of manufacturing from the anode side has been described, but it may be manufactured from the cathode side.
  • a method for manufacturing an organic EL element according to the tenth embodiment of the present invention will be described.
  • a recess corresponding to the lens structure 308 is formed in the substrate 301.
  • the forming method is not particularly limited, and machining such as cutting and polishing, laser processing, and the like can be used.
  • the lens structure 308 is formed so as to fill the formed concave portion.
  • Forming methods include a method of applying and converting a spin-on dielectric, a method of applying and curing a curable resin, and the like.
  • As a coating method various processes such as spin coating, bar coating, slit coating, die coating, and spray coating can be used.
  • the anode 302, the organic layer 303, the cathode 304, the low refractive index layer 305, and the metal layer 306 are formed on the formed lens structure 308.
  • the same method as in the second embodiment can be used.
  • the organic EL element 300 can be manufactured through the above steps. In the above manufacturing method of the organic EL element, the method of manufacturing from the anode side has been described, but it may be manufactured from the cathode side.
  • Example 1 is an example of the first embodiment of the present invention.
  • an ITO layer having a thickness of 150 nm as the anode 2 a hole injection layer (part of the layer 19) composed of 40 nm pTmTDMPD: F4TCNQ (100: 5) as the organic layer 103, and a 20 nm m-TTA Hole transport layer (part of layer 19), light-emitting layer A (part of light-emitting layer 3) consisting of 20 nm PH-2: BFA-1T (10:90), 10 nm PH-1: PyTMB ( 10:90) light-emitting layer B (part of light-emitting layer 3), 20 nm of Alq 3 electron transport layer (part of organic thick film layer 18), 100 nm of BCP: Cs (20: 1) A sample in which an electron injection layer (a part of the organic thick film layer 18), a 50 nm ITO layer as the cathode 4, a layer made of 150 n
  • Example 2 is an example of the fifth embodiment of the present invention.
  • the cathode side structure, the organic thick film layer and the light emitting layer, and the hole transport layer are the same as in Example 1, but a part of the anode side structure is different. That is, on the glass substrate 41, an ITO layer having a thickness of 150 nm as the anode 42, a 150 nm SiO 2 film as the dielectric layer 47, and a hole injection layer made of 20 nm pTmTDMPD: F4TCNQ (100: 5) as the organic layer 43.
  • Part of layer 19 hole transport layer (part of layer 19) made of 20 nm m-TTA, light emitting layer A (light emitting layer 3) made of 20 nm PH-2: BFA-1T (10:90)
  • a light emitting layer B made of 10 nm PH-1: PyTMB (10:90) (a part of the light emitting layer 3), an electron transport layer made of 20 nm of Alq3 (a part of the organic thick film layer 18), 100 nm BCP: Cs (50:50) electron injection layer (part of organic thick film layer 18), cathode 44 as 50 nm ITO layer, low refractive index layer 45 as 150 nm MgF 2 layer, metal layer A sample was prepared by sequentially laminating a 100 nm Ag layer as 46.
  • the total thickness of the organic thick film layer 18 was 120 nm.
  • the driving voltage required to obtain a luminance of 100 cd / m 2 for the obtained sample was 4.4V.
  • the external quantum efficiency was 1.8 when Comparative Example 3 described later is 1.
  • Comparative Example 1 Compared with Example 1, there is no ITO layer as a cathode and a layer made of MgF 2 as a low refractive index layer, and a difference is that a 100 nm Ag layer is provided as a cathode. Comparative Example 1 is provided with a layer corresponding to the organic thick film layer of Examples 1 and 2, except that it does not have an Otto type cathode side structure. That is, an ITO film having a thickness of 150 nm as an anode on a glass substrate, a hole injection layer made of 40 nm pTmTDMPD: F4TCNQ (100: 5), a hole transport layer made of 20 nm m-TTA, and 20 nm as an organic layer.
  • PH-2 Emission layer A made of BFA-1T (10:90), 10 nm emission layer B made of PH-1: PyTMB (10:90), 20 nm electron transport layer made of Alq 3 , 100 nm BCP
  • a sample was prepared by laminating an electron injection layer made of: Cs (50:50) and a 100 nm Ag layer as a cathode.
  • the driving voltage required to obtain a luminance of 100 cd / m 2 for the obtained sample was 4.9V.
  • the external quantum efficiency was 1.1 when Comparative Example 3 described later is 1.
  • Comparative Example 2 Compared with Example 2, there is no ITO layer as a cathode and a layer made of MgF 2 as a low refractive index layer, and a difference is that a 100 nm Ag layer is provided as a cathode.
  • the driving voltage required to obtain a luminance of 100 cd / m 2 for the obtained sample was 5.0V.
  • the external quantum efficiency was 1.3 when Comparative Example 3 described later is 1.
  • Comparative Example 3 Compared to Comparative Example 1, the difference is that the thickness of the electron injection layer is 20 nm. That is, an ITO film having a thickness of 150 nm as an anode on a glass substrate, a hole injection layer made of 40 nm pTmTDMPD: F4TCNQ (100: 5), a hole transport layer made of 20 nm m-TTA, and 20 nm as an organic layer.
  • a sample was prepared by laminating an electron injection layer made of: Cs (50:50) and a 100 nm Ag layer as a cathode.
  • the driving voltage required to obtain a luminance of 100 cd / m 2 for the obtained sample was 4.6V.
  • the external quantum efficiency was set to 1 in Comparative Example 3.
  • Example 4 Compared to Example 1, the difference is that the thickness of the BCP: Cs (50:50) layer as the electron injection layer is 350 nm. That is, an ITO film having a thickness of 150 nm as an anode on a glass substrate, a hole injection layer made of 40 nm pTmTDMPD: F4TCNQ (100: 5), a hole transport layer made of 20 nm m-TTA, and 20 nm as an organic layer.
  • the thickness of the BCP: Cs (50:50) layer as the electron injection layer is 350 nm. That is, an ITO film having a thickness of 150 nm as an anode on a glass substrate, a hole injection layer made of 40 nm pTmTDMPD: F4TCNQ (100: 5), a hole transport layer made of 20 nm m-TTA, and 20 nm as an organic layer.
  • PH-2 a light emitting layer A composed of BFA-1T (10:90), a light emitting layer B composed of 10 nm PH-1: PyTMB (10:90), an electron transport layer composed of 20 nm Alq 3 , a BCP of 350 nm
  • a sample was prepared by sequentially laminating an electron injection layer composed of Cs (50:50), a 50 nm ITO layer as a cathode, a 150 nm MgF 2 layer as a low refractive index layer, and a 100 nm Ag layer as a metal layer.
  • the total thickness of the organic thick film layer was 370 nm.
  • the driving voltage required to obtain a luminance of 100 cd / m 2 for the obtained sample was 5.2V.
  • the external quantum efficiency was 0.8 when the above-described Comparative Example 3 was 1.
  • Substrate 11A Recess 11a Recessed inner surface 2, 12, 22, 32, 42, 52, 62, 82, 92, 302
  • Anode 12A, 32A , 42A, 52A Anode hole portion 12a, 22a, 32a, 42a, 52a Inner side surface of anode hole portion 3, 13, 23, 33, 43, 53, 63, 83, 93, 303 Organic layer 4, 14, 24, 34 44, 54, 64, 84, 94, 304
  • Cathode 5 15, 25, 35, 45, 55, 65, 85, 95, 305

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Abstract

La présente invention concerne un élément EL organique (10) qui est équipé, dans cet ordre, sur un substrat (1), d'une anode (2), d'une couche organique (103), qui comprend une couche électroluminescente (3), qui comprend un matériau EL organique, et d'une cathode (4), et ledit élément EL organique est en outre équipé d'une couche à faible indice de réfraction (5) et d'une couche métallique (6), dans cet ordre, sur la cathode (4) sur son côté opposé à la couche organique (3), et est caractérisé en ce que l'indice de réfraction de la couche à faible indice de réfraction (5) est inférieur à celui de la couche organique (103), la couche organique (103) contient une couche à film épais organique (18) qui possède une épaisseur de film de 10 à 300 nm, inclus, entre la couche électroluminescente (3) et la cathode (4), et la distance entre la couche électroluminescente (3) et la couche métallique (6) est 100 à 400 nm, inclus.
PCT/JP2013/082046 2012-11-30 2013-11-28 Élément el organique, et dispositif d'affichage d'image et dispositif d'éclairage équipés dudit élément el organique WO2014084308A1 (fr)

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