WO2014069565A1 - Élément électroluminescent organique et dispositif d'affichage d'image et dispositif d'éclairage équipés dudit élément - Google Patents

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

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WO2014069565A1
WO2014069565A1 PCT/JP2013/079535 JP2013079535W WO2014069565A1 WO 2014069565 A1 WO2014069565 A1 WO 2014069565A1 JP 2013079535 W JP2013079535 W JP 2013079535W WO 2014069565 A1 WO2014069565 A1 WO 2014069565A1
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substrate
organic
transparent electrode
refractive index
light
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PCT/JP2013/079535
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English (en)
Japanese (ja)
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祐介 山▲崎▼
祥貴 下平
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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
    • H10K59/805—Electrodes
    • H10K59/8052—Cathodes
    • H10K59/80521—Cathodes 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
    • 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
    • H10K59/10—OLED displays
    • H10K59/17—Passive-matrix OLED displays

Definitions

  • the present invention relates to an organic EL element, and an image display device and an illumination device including the organic EL element.
  • This application claims priority based on Japanese Patent Application No. 2012-241333 filed in Japan on October 31, 2012 and Japanese Patent Application No. 2013-074379 filed on March 29, 2013 in Japan, The contents are incorporated here.
  • Organic EL elements have features such as a wide viewing angle, high-speed response, clear self-luminous display, etc., and they are thin, lightweight, and have low power consumption. It is expected as a pillar of 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. . In a top emission type organic EL element, a transparent electrode must be formed on the organic light emitting layer, and therefore the organic light emitting layer is easily damaged. The bottom emission type organic EL element does not have such a problem and has an advantage that it is easy to manufacture.
  • 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, a small incident angle that is less than the critical angle at the interface between a transparent substrate (for example, glass (typical refractive index: 1.52)) and air (refractive index: 1.0). Light incident at (the angle formed by the incident light and the normal of the incident interface) is refracted at the interface and extracted outside the device. 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.
  • a transparent electrode for example, indium tin oxide alloy (ITO (typical refractive index: 1.82)
  • a transparent substrate for example, glass (typical) made of a transparent conductive oxide.
  • the light incident on the interface with a refractive index of 1.52)) having an incident angle larger than the critical angle is totally reflected at the interface and is not taken out of the device, but can be finally absorbed by the material.
  • this light is called waveguide mode light, and the loss due to this is called waveguide loss.
  • the light emitted from the light emitting layer is incident on the metal electrode and combined with the free electrons of the metal electrode, and the light captured on the surface of the metal electrode as surface plasmon polariton (SPP) is also outside the device. And can be finally absorbed into the material.
  • SPP mode light the resulting loss 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.
  • 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). It can be said that research has just begun on the reduction and removal of odors.
  • 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 lower refractive index than the organic light emitting layer and the transparent electrode in the organic light emitting layer and the transparent electrode. It is disclosed.
  • Patent Documents 4 and 5 disclose a configuration in which a cavity is provided in a transparent electrode layer and a dielectric layer that are 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. The light refracted to the substrate side can reduce the proportion of light that causes total reflection at the interface between the transparent electrode and the substrate and between the substrate and the air.
  • Patent Documents 6 to 9 As a method for extracting the SPP mode light trapped on the surface of the metal electrode, a configuration in which a periodic uneven structure is formed on the surface of the metal electrode is known (Patent Documents 6 to 9).
  • the SPP mode light can be extracted as propagating light, the light extraction efficiency cannot be improved unless the light becomes guided mode light and can be extracted outside the device.
  • the SPP mode light can be expected to exhibit a light emission enhancement effect by surface plasmon excitation.
  • the present invention has been made in view of the above circumstances, and provides an organic EL element in which SPP mode light and waveguide mode light are effectively extracted to improve light extraction efficiency, and an image display device and an illumination device including the organic EL element.
  • the purpose is to do.
  • the present inventors first assume a number of light extraction mechanisms that take out a SPP mode light as propagating light and then extract the propagating light to the outside of the device without making it a guided mode light.
  • the structures we have intensively studied effective structures that improve the light extraction efficiency. Since it is difficult to directly measure the light extraction efficiency, we examined it based on simulation.
  • the two-step light extraction mechanism generates a SPP mode light, and has a metal electrode side structure having a plurality of radiation concavo-convex portions arranged periodically to enable the generated SPP mode light to be extracted as propagating light; It consists of a transparent electrode side structure provided with a lens structure for extracting the light extracted as the propagating light to the outside without using it as guided mode light.
  • the metal electrode-side structure radiation uneven portion is a portion from which the SPP mode light captured on the metal electrode surface is re-radiated, and is a dot-like or line-like convex or concave portion formed on the metal electrode surface. It is.
  • the SPP mode light will be lost as heat.
  • the SPP mode light is re-emitted as propagating light centering on.
  • the transparent electrode side structure As the transparent electrode side structure, a lens-like structure was introduced that refracts the light radiated from the radiation uneven portion of the metal electrode side structure so as to enter the substrate as much as possible from the orthogonal direction. More specifically, for example, a structure having a lens structure that protrudes to the substrate side or the organic layer side at any interface between the substrate and the organic layer, or a lens structure that the substrate protrudes to the atmosphere side.
  • substrate was comprised.
  • the present inventors refract the metal electrode side structure having a radiation uneven portion and the light emitted from the radiation uneven portion of the metal electrode side structure so as to enter from a direction more orthogonal to the substrate by simulation.
  • the transparent electrode side structure provided with the lens-like structure it has been found that the metal electrode side structure and the transparent electrode side structure have a remarkable effect that cannot be predicted from the single configuration, and the present invention has been completed. It was.
  • An organic EL device comprising a transparent electrode, an organic layer including a light emitting layer, and a metal electrode in this order, and the metal electrode is periodically arranged in at least one direction on the surface of the organic layer.
  • the lens structure having a plurality of radiation irregularities comprising a plurality of lens structures extending in the in-plane direction of the element plane between the surface of the organic layer and the element outer surface on the transparent electrode side. Are arranged in the one direction with the same period as the period of the radiation uneven part.
  • a substrate is provided on a surface of the transparent electrode opposite to the organic layer, and the transparent electrode and the substrate are protruded from a side having a lower refractive index at the interface between the transparent electrode and the substrate.
  • the organic EL device according to (1) which has a one-lens structure.
  • a substrate is provided on the surface of the transparent electrode opposite to the organic layer, and a second lens structure protruding outside the element is provided on the surface of the substrate opposite to the transparent electrode.
  • the interface between the transparent electrode and the organic layer is provided with a third lens structure that protrudes to the low refractive index side of the organic layer and the transparent electrode.
  • the organic EL element as described in any one of 3).
  • the transparent electrode is provided with a second dielectric layer and a first dielectric layer in order from the transparent electrode side on the surface opposite to the organic layer, and the second dielectric layer is the transparent electrode.
  • a refractive index difference of 0.1 or less or a refractive index higher than that of the transparent electrode, and a refractive index difference between the first dielectric layer and the second dielectric layer is 0.2 or more, (1), (3) or (4), wherein the interface between the first dielectric layer and the second dielectric layer is provided with a fourth lens structure projecting to a lower refractive index side.
  • Organic electroluminescent element as described in any one of these.
  • a substrate is provided on the surface of the transparent electrode opposite to the organic layer, a dielectric layer is provided between the substrate and the transparent electrode, and the dielectric layer has a refractive index of the transparent electrode.
  • the refractive index difference of 0.1 or less or higher than that of the transparent electrode, the refractive index difference of the dielectric layer and the substrate is 0.2 or more, and the interface between the dielectric layer and the substrate.
  • a substrate is provided on the surface of the transparent electrode opposite to the organic layer, a dielectric layer is provided between the substrate and the transparent electrode, and a refractive index difference between the transparent electrode and the dielectric layer. Is 0.2 or more, and the interface between the transparent electrode and the dielectric layer is provided with a sixth lens structure projecting to a lower refractive index side (1), (3) Organic EL element as described in any one of (4).
  • a substrate is provided on a surface of the transparent electrode opposite to the organic layer, a dielectric layer is provided on a surface of the substrate opposite to the transparent electrode, and the dielectric layer is formed on the substrate.
  • a seventh lens structure that has a refractive index difference of 0.1 or less or a refractive index higher than that of the substrate and protrudes on the opposite side of the substrate (1), 2)
  • the organic EL device according to any one of (4) to (7).
  • a transparent conductive layer is provided between the transparent electrode and the organic layer, a difference in refractive index between the transparent conductive layer and the organic layer is 0.2 or more, and the transparent conductive layer and the organic layer are organic.
  • the organic layer according to any one of (1) to (3) and (5) to (8), wherein the interface with the layer includes an eighth lens structure protruding toward the transparent conductive layer.
  • EL element
  • a substrate is provided on a surface of the transparent electrode opposite to the organic layer, a dielectric layer is provided on the opposite side of the substrate from the transparent electrode, and the dielectric layer has a refractive index of the substrate.
  • (1), (2) having a ninth lens structure having a refractive index difference of 0.2 or more and protruding to the lower refractive index side at the interface between the dielectric layer and the substrate.
  • (4) to (7) The organic EL device according to any one of (9).
  • (11) A substrate is provided on a surface of the transparent electrode opposite to the organic layer, and a third dielectric layer and a fourth dielectric layer are sequentially arranged from the substrate side on the opposite side of the transparent electrode of the substrate.
  • the third dielectric layer has a refractive index difference of 0.1 or less or a refractive index higher than that of the substrate, and the refractive index of the third dielectric layer and the fourth dielectric layer.
  • the difference is 0.2 or more, and the tenth lens structure protruding to the lower refractive index side is provided at the interface between the third dielectric layer and the fourth dielectric layer (1). ), (2), (4) to (7), and the organic EL device according to any one of (9).
  • a substrate is provided on the surface of the metal electrode opposite to the organic layer, and an eleventh lens structure protruding outside the element is provided on the surface of the transparent electrode opposite to the substrate ( The organic EL device according to any one of 1), (4), and (9).
  • a substrate is provided on the surface of the metal electrode opposite to the organic layer, a dielectric layer is provided on the opposite side of the transparent electrode from the substrate, and the refractive index of the dielectric layer is the transparent
  • a twelfth lens having a refractive index difference of 0.1 or less or a refractive index higher than the refractive index of the transparent electrode and protruding outside the element on the surface opposite to the transparent electrode of the dielectric layer
  • the organic EL device according to any one of (1), (4), and (9), characterized by comprising a structure.
  • the organic EL element according to any one of (1) to (13), wherein the center of the lens structure is disposed on a substrate normal passing through the center of the radiation uneven portion.
  • An image display device comprising the organic EL element according to any one of (1) to (15).
  • An illuminating device comprising the organic EL element according to any one of (1) to (15).
  • an organic EL element in which SPP mode light and waveguide mode light are effectively extracted to improve light extraction efficiency, and an image display device and an illumination device including the organic EL element.
  • FIG. 1 is a schematic cross-sectional view for explaining an example of an organic EL element according to a first embodiment of the present invention. It is a cross-sectional schematic diagram for demonstrating the effect of the organic EL element shown in FIG. It is a cross-sectional schematic diagram for demonstrating an example of the organic EL element which concerns on the 2nd Embodiment of this invention. It is a cross-sectional schematic diagram for demonstrating an example of the organic EL element which concerns on the 3rd Embodiment of this invention. It is a cross-sectional schematic diagram for demonstrating the effect of the organic EL element shown in FIG.
  • FIG. 6 is a schematic cross-sectional view for explaining a modification of the organic EL element according to the first to third embodiments of the present invention.
  • FIG. 17 is a schematic view of a cross section along the normal direction of the metal electrode surface, illustrating a concave radiation uneven portion having the same shape as the convex shape shown in FIG. 16. It is a schematic diagram of a cross section along another normal direction of the metal electrode surface, showing another example of a convex radiation uneven portion.
  • FIG. 19 is a schematic illustration of a cross section along the normal direction of the metal electrode surface, illustrating a concave radiation uneven portion having the same shape as the convex shape shown in FIG. 18. It is a cross-sectional schematic diagram for demonstrating an example of the image display apparatus provided with the organic EL element of this invention. It is a cross-sectional schematic diagram for demonstrating an example of the illuminating device provided with the organic EL element of this invention.
  • FIG. 20 is a plan view for explaining an example of a combination of a radiation uneven portion and a lens structure shown in FIGS. 16 to 19;
  • FIG. 16 shows the result of computer simulation calculation of the light extraction efficiency using the FDTD method for the combination of the convex radiation uneven portion and the lens structure shown in FIGS. 16 (a) to (c), (h), and (d). .
  • It is sectional drawing which shows the model structure of the organic EL element of 5th Embodiment used by simulation calculation.
  • FIG. 20 is a plan view for explaining an example of a combination of a radiation uneven portion and a lens structure shown in FIGS. 16 to 19;
  • FIG. 16 shows the result of computer simulation calculation of the light extraction efficiency using the FDTD method for the combination of the convex radiation uneven portion and the lens structure shown in FIGS. 16 (a) to (c), (h), and (d). .
  • It is sectional drawing which shows the model structure of the organic EL element of 5th Embodiment used by simulation calculation.
  • FIGS. 17 shows the result of computer simulation calculation of the light extraction efficiency using the FDTD method for the combination of the convex radiation uneven portion and the lens structure shown in FIGS. 16 (e) to (g).
  • FIG. 18 shows the result of computer simulation calculation of the light extraction efficiency using the FDTD method for the combination of the concave radiation uneven portion and the lens structure shown in FIGS. 17 (i) to (l) and (p).
  • FIG. 18 shows the result of computer simulation calculation of the light extraction efficiency using the FDTD method for the combination of the concave radiation uneven portion and the lens structure shown in FIGS.
  • one of the transparent electrode and the metal electrode is an anode and the other is a cathode.
  • the present invention may be applied to either a so-called top emission type or bottom emission type.
  • the lens structure of one embodiment may be applied to other embodiments.
  • the organic EL device of the present invention may include a layer not described below as long as the effects of the present invention are not impaired.
  • the organic EL device of the present invention is an organic EL device comprising a transparent electrode, an organic layer including a light emitting layer, and a metal electrode in this order.
  • the metal electrode has a plurality of radiation uneven portions that are periodically arranged in at least one direction on the surface of the organic layer.
  • a plurality of lens structures extending in the in-plane direction of the element plane are provided between the surface of the organic layer and the outer surface of the element on the transparent electrode side, and the lens structure is the same as the period of the radiation uneven portion in one direction. Arrange in a cycle.
  • the substrate on the atmosphere side surface of the substrate And a configuration including a plurality of lens structures separately from the substrate.
  • a configuration in which a plurality of lens structures extending in the in-plane direction of the element plane is provided between the surface of the organic layer and the outer surface of the element on the transparent electrode side is, for example, a substrate and an organic layer A structure having a lens structure protruding to the substrate side or the organic layer side at any of the interfaces, a structure having a lens structure protruding to the atmosphere side, or a transparent electrode of the substrate
  • the structure etc. which are provided with the lens structure where the layer provided on the opposite side protrudes to the atmosphere side are mentioned.
  • 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.
  • FIG. 1A shows a configuration in which the lens structure 2a protrudes toward the substrate 1 (a configuration in which the substrate 1 has a concave lens structure, or a configuration in which a lens structure is provided at the interface between the substrate 1 and the transparent electrode 2).
  • FIG. 1B shows a configuration in which a lens structure 1a (a configuration in which the transparent electrode 2 has a concave lens structure, a configuration in which a lens structure is provided at the interface between the substrate 1 and the transparent electrode 2) protrudes toward the metal electrode 4 side. It is.
  • the 1A includes a transparent electrode 2, an organic layer 3 including a light emitting layer, and a metal electrode 4 in this order on a substrate 1, and takes out light from the transparent electrode side to the outside.
  • This is an organic EL element configured as described above.
  • the metal electrode 4 has a plurality of radiation uneven portions 4a periodically arranged in at least one direction on the surface 4A on the organic layer side.
  • FIG. 1 shows a case where the cross section of the radiation uneven portion 4a is a rectangular recess. Show.
  • the transparent electrode 2 includes a lens structure (first lens structure) 2a that has a refractive index higher than that of the substrate and protrudes toward the substrate at the interface with the substrate 1, and the lens structure 2a has radiation unevenness.
  • the same period means that there is a common repeating unit in the plan view arrangement of the center of the radiation uneven portion and the center of the lens structure. Therefore, it is necessary that the ratio of the distance between adjacent lenses (cycle) and the distance between adjacent projections and depressions (cycle) is an integer ratio (1: n or n: 1, where n is an integer of 1 to 10). is there.
  • the same cycle means substantially the same cycle as long as the effect of the present invention is not impaired. This also applies to the following embodiments.
  • This organic EL element is a bottom emission type organic EL element that extracts light emitted from the light emitting layer from the substrate side.
  • a substrate 1 is a translucent substrate 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 it is not necessary 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. Specifically, a glass plate, a polymer plate, etc. are mentioned.
  • the glass plate material examples include soda lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz.
  • the material for the polymer plate examples include polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polyether sulfide, and polysulfone.
  • the substrate 1 includes a recess 1 a corresponding to the lens structure 2 a of the transparent electrode 2. Therefore, the material of the substrate 1 is preferably a material that can be processed more precisely and is not limited. For example, preferred materials include glass plates and polymer plates. The above-mentioned materials can be used as specific materials for the glass plate and the polymer plate.
  • the substrate 1 includes a layered portion 1d integrated with the concave portion 1c on the atmosphere side of the concave portion 1c. The thickness of the layered portion 1d depends on the required mechanical strength and is not limited, but is preferably 0.01 mm to 10 mm, more preferably 0.05 mm to 2 mm.
  • the transparent electrode 2 has a refractive index higher than that of the substrate 1.
  • the transparent electrode 2 includes a lens structure 2a that protrudes toward the substrate at the interface with the substrate, and a layered portion 2d that is formed integrally with the lens structure 2a on the organic layer side of the lens structure 2a.
  • the interface 9 between the substrate 1 and the transparent electrode 2 has a convex curved surface of the lens structure 2a protruding to the substrate side, and the substrate 1 is a concave portion having a shape complementary to the shape of the lens structure 2a of the transparent electrode 2. 1c.
  • the refractive index of the transparent electrode 2 is preferably higher than the refractive index of the substrate 1 by 0.2 or more.
  • the reason why the difference in refractive index is 0.2 or more is that light is refracted at the interface to exhibit a sufficient light collecting effect as a lens.
  • the thickness of the layered portion 2d of the transparent electrode 2 is not limited. For example, it is 10 to 2000 nm, preferably 50 to 1000 nm. This is because the sheet resistance of the transparent electrode 2 increases when the thickness is less than 10 nm, and the transmittance of the transparent electrode 2 decreases when the thickness is greater than 2000 nm.
  • the height h of the lens structure 2a of the transparent electrode 2 is not limited.
  • the width w is not limited.
  • the height h is 1 to 50 times, preferably 2 to 20 times. If the height h is lower than 150 nm, the light reflected from the front surface and the back surface of the lens interferes with each other, and the lens may not perform the light collecting function.
  • the thickness is larger than 50 ⁇ m, the undulation of the lens structure 2a is increased, and the surface on the organic layer 3 side is hardly flattened when the transparent electrode 2 is formed.
  • the width w is smaller than 1 times h, the curvature of the lens becomes too large, so that the re-radiated light from the radiating uneven portion incident on the outer peripheral portion of the lens is difficult to be directed to the front. If it is larger than 50 times h, the curvature of the lens becomes small, and the re-radiated light may not be collected in the front.
  • the arrangement period p of the lens structure 2a is not limited.
  • the thickness is 300 nm to 100 ⁇ m, preferably 2 to 20 ⁇ m. If p is shorter than 300 nm, the lens may be unable to focus due to the effect of the diffraction grating.
  • the cross-sectional shape of the lens shape is not particularly limited as long as it has a function of directing re-radiated light from the radiation uneven portion in the front direction.
  • a semicircular shape, a spherical lens shape, an aspherical lens shape, a convex polygonal shape, a Fresnel lens shape, and the like can be given.
  • the planar shape of the lens is not particularly limited, and examples thereof include a circle, an ellipse, a line (rod) shape, and a polygon.
  • the transparent electrode 2 is an electrode for applying a voltage between the metal electrode 4 and injecting holes into the light emitting layer from the transparent electrode 2. It is preferable to use a material made of It is preferable to use a work function of 4 eV or more and 6 eV or less so that the difference from the HOMO (Highest Occpupied Molecular Orbital) level does not become excessive.
  • the material of the transparent electrode 2 is not particularly limited as long as it is a translucent and conductive material.
  • transparent conductive oxides such as indium tin oxide alloy (ITO), zinc oxide tin alloy (IZO), tin oxide and zinc oxide, and a mixture of poly (3,4) -ethylenedioxythiophene and polystyrene sulfonate (PEDOT: PSS), conductive polymers such as polyaniline and conductive polymers doped with any acceptor, conductive light-transmitting materials such as carbon nanotubes, thin film metals, and composite materials containing these.
  • the transparent electrode 2 can be formed on the substrate 1 by, for example, a sputtering method, a vacuum evaporation method, a coating method, a CVD method, an ion plating method, or the like.
  • the metal electrode 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 low work function. It is preferable to use a work function of 1.9 eV or more and 5 eV or less so that the difference from the LUMO (Lowest Unoccpupied Molecular Orbital) level does not become excessive.
  • the thickness of the metal electrode 4 is not limited. For example, it is 30 nm to 1 ⁇ m, preferably 50 to 500 nm. If the thickness is less than 30 nm, the sheet resistance increases and the drive voltage increases. If it is thicker than 1 ⁇ m, damage due to heat and radiation during film formation and mechanical damage due to film stress accumulate in the electrode and organic layer.
  • the radiation uneven portion is not particularly limited as long as a specific non-flat structure is periodically arranged on the flat metal electrode surface. This is because SPP mode light can be re-emitted as propagating light if the surface of the metal electrode is non-flat.
  • the arrangement period of the radiation uneven portion is preferably 10 ⁇ m or less in which the SPP mode light can propagate.
  • the radiation uneven portion 4a shown in FIG. 1 has a concave structure with a rectangular cross section, but can have various shapes of structures as illustrated later in addition to the rectangular convex structure.
  • corrugated part 4a is a structure arrange
  • the structure can be taken.
  • one radiation uneven part (unit structure of the radiation uneven part) may be composed of one concave structure or convex structure, or may be composed of a plurality of concave structures and / or convex structures.
  • the size of each radiation uneven portion is preferably smaller than the diameter of the lens structure (width in the case of a line shape) in plan view.
  • the radiation uneven part is a line-like uneven part, the width of each radiation uneven part is preferably smaller than the diameter of the lens structure (in the case of a line form) in plan view.
  • the lens structure is arranged at the same period as the period of the radiation uneven part in the direction in which the radiation uneven part is periodically arranged.
  • the lens structure is arranged at equal intervals along each line of the radiation uneven portion.
  • the lens structure columns arranged in a line are arranged in parallel.
  • the center line in the width direction of the line of the radiation uneven portion and the column of the lens structure arranged along the same coincide in plan view.
  • each radiation uneven portion is arranged at a position overlapping the lens structure in plan view. In this configuration, it is preferable that each dot-shaped radiation uneven portion is disposed at the center of each lens structure.
  • the organic layer 3 is disposed between the layered portion 2d of the transparent electrode 2 and the metal electrode 4, and has the layered portion 3d and a convex portion 3e having a shape complementary to the shape of the radiation concave-convex portion 4a of the metal electrode 4. .
  • the shape of the portion complementary to the radiation uneven portion 4a is a convex shape, but may be other shapes as long as it is complementary to the shape of the radiation uneven portion 4a. Further, it is not necessary to fit (fit) the shape of the radiation uneven portion 4a.
  • the organic layer 3 may include a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, and the like.
  • the hole injection layer is a layer that assists the injection of holes into the light emitting layer
  • the hole transport layer is a layer that transports holes to the light emitting region, and has a high hole mobility and usually has an ionization energy of 5.5 eV. The following is small.
  • Such a hole injection layer and a hole transport layer are preferably materials that transport holes to the light emitting layer with lower electric field strength.
  • the material for forming this is not particularly limited as long as it can perform the above functions, and any material can be selected and used from known materials.
  • the organic layer 3 may be formed by a dry process such as an evaporation method or a transfer method, or 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 3 is not particularly limited. For example, it is 50 to 2000 nm, preferably 100 to 1000 nm. When the thickness is less than 50 nm, quenching other than metal SPP coupling occurs, such as a decrease in internal QE due to a punch-through current and lossy surface wave mode coupling. When it is thicker than 2000 nm, the driving voltage increases.
  • FIG. 1A The function and effect of the organic EL element shown in FIG. 1A will be schematically described with reference to FIG.
  • the light propagation method indicated by the arrows in FIG. 2 is schematically shown for easy understanding of the principle of the effect.
  • the refraction of light other than the lens structure such as the interface between the organic layer 3 and the transparent electrode 2 is omitted.
  • FIG. 2 since each layer is the same as that in FIG. 1, symbols of each layer and each part are omitted.
  • the light traveling to the metal electrode 4 side (arrow A1) is captured by the surface 4A of the metal electrode 4, and then is applied to the surface 4A as SPP mode light. It moves along (arrow A2) and is re-emitted as propagating light at the radiating uneven portion 4a 1 (4a) (arrow A3, A4), passes through the organic layer 3 and enters the transparent electrode 2.
  • the light reaching the interface between the lens structure 2a 1 (2a) of the transparent electrode 2 and the recess 1c 1 (1c) of the substrate 1 enters the substrate from the transparent electrode having a refractive index higher than that of the substrate.
  • the center line of the lens structure refers to a line that passes through the center of the bottom surface of the lens structure and extends in the normal direction of the substrate surface.
  • the bottom surface of the lens has a line (rod) shape, it is an arbitrary normal of the substrate surface passing through the center line of the line width.
  • the light is refracted toward the center line CC side of the lens structure 2a and is taken out of the substrate 1. Thereby, the extraction of light in the front direction of the substrate increases.
  • the description given above with reference to FIGS. 1A and 2 is for the case where the refractive index of the transparent electrode 2 is higher than the refractive index of the substrate 1.
  • the organic EL element shown in FIG. 1B has a configuration in which the protruding direction of the lens structure faces the opposite side with respect to the organic EL element shown in FIG.
  • the organic EL element shown in FIG. when the material of the substrate 1 and the transparent electrode 2 is selected so that the refractive index of the substrate 1 is higher than the refractive index of the transparent electrode 2, the organic EL element shown in FIG.
  • the lens action (condensing function) similar to the lens action in the organic EL element shown in FIG. That is, the same light extraction effect as that of the organic EL element shown in FIG.
  • the substrate 1 includes a lens structure 1a having a refractive index higher than that of the transparent electrode 2 and protruding toward the metal electrode at the interface with the transparent electrode 2. It arrange
  • the refractive index of the transparent electrode 2 is preferably 0.2 or more lower than the refractive index of the substrate 1. The reason why the difference in refractive index is 0.2 or more is that light is refracted at the interface to exhibit a sufficient light collecting effect as a lens.
  • a conductive polymer such as PEDOT: PSS typically refractive index: 1.5
  • PEDOT: PSS typically refractive index: 1.5
  • a high refractive index substrate may be used.
  • Specific examples of the material for the high refractive index substrate include LaSFN9 (trade name) (refractive index: 1.85) manufactured by Shot Japan Co., Ltd., and K-PSFn3 (refractive index: 1.84) manufactured by Sumita Optical Glass Co., Ltd. K-LaSFn17 (refractive index: 1.88), K-LaSFn22 (refractive index: 1.90), and the like.
  • the organic EL element of this embodiment even if the light emitted from the light emitting layer included in the organic layer is captured as SPP mode light on the surface of the metal electrode, the SPP mode light is radiated unevenness on the surface of the metal electrode. It can be re-radiated as propagating light and extracted. Furthermore, the light extracted from the surface of the metal electrode can be refracted in the front direction of the substrate by the lens structure at the interface between the transparent electrode and the substrate to increase the amount of light extracted in the front direction of the substrate.
  • FIG. 3 is a schematic cross-sectional view for explaining an example of the organic EL element according to the second embodiment of the present invention.
  • the organic EL element 20 shown in FIG. 3 includes a transparent electrode 12, an organic layer 13 including a light emitting layer, and a metal electrode 14 in order on a substrate 11, and is configured to extract light from the transparent electrode side to the outside. It is the made organic EL element.
  • the metal electrode 14 has a plurality of radiation uneven portions 14a periodically arranged in at least one direction on the surface 14A on the organic layer side.
  • the substrate 11 is provided with a lens structure (second lens structure) 11a that protrudes outside the element on the surface opposite to the transparent electrode, and the lens structure 11a is arranged in a direction in which the radiation uneven portions 14a are periodically arranged. It arrange
  • the substrate 11 includes a lens structure 11a that protrudes toward the atmosphere on the surface opposite to the transparent electrode 12, and a layered portion 11d that is integrated with the lens structure 11a on the transparent electrode 12 side of the lens structure 11a. Since this organic EL element is also a bottom emission type organic EL element like the organic EL element of the first embodiment, the material of the substrate 11 and the thickness of the layered portion 11d are the same as those of the first embodiment. A substrate similar to the substrate 1 can be used. In the present embodiment, the substrate 11 includes a lens structure 11a. Therefore, like the organic EL element of the first embodiment, a material that is easy to process more precisely is preferable.
  • the same material as the transparent electrode material of the first embodiment can be used.
  • the thickness of the transparent electrode 12 is not particularly limited. For example, it is 10 to 2000 nm, preferably 50 to 1000 nm. If it is thinner than 10 nm, the sheet resistance of the transparent electrode 12 increases. If it is thicker than 2000 nm, the transmittance of the transparent electrode 12 is lowered.
  • the metal electrode 14 has a plurality of radiation uneven portions 14a periodically disposed in at least one direction on the surface 14A on the organic layer side.
  • the period in at least one direction of the radiation uneven portion 14a is the same as the period in one direction of the lens structure 11a.
  • the configuration of the radiation uneven portion 14a can be the same as that of the organic EL element of the first embodiment.
  • the metal electrode 14 may be the same material and thickness as in the first embodiment.
  • the organic layer 13 is disposed between the transparent electrode 12 and the metal electrode 14 and is complementary to the shape of the layered portion 13d and the radiation uneven portion 14a of the metal electrode 14. And a convex portion 13e having a shape.
  • the same material and thickness as those in the first embodiment can be used.
  • the SPP mode light captured on the surface of the metal electrode Is re-radiated as propagating light at the radiation uneven portion 14 a on the surface of the metal electrode and extracted, passes through the organic layer 13 and the transparent electrode 12, and enters the substrate 11. Then, the light that reaches the interface between the lens structure 11a 1 (11a) of the substrate 11 and the atmosphere exits from the lens structure 11a of the substrate 11 having a refractive index higher than the refractive index of the atmosphere to the atmosphere. 1 (11a) refracts toward the center line CC side.
  • the lens structure 11a As described above, even if the light re-radiated as the propagation light by the radiation uneven portion 14a of the metal electrode 14 is incident on the lens structure 11a in the direction away from the center line CC of the lens structure 11a of the substrate 11, the lens structure 11a The light is refracted toward the center line CC and is taken out of the substrate 11. Thereby, the extraction of light in the front direction of the substrate increases.
  • the organic EL element of this embodiment even if the light emitted from the light emitting layer included in the organic layer is captured as SPP mode light on the surface of the metal electrode, the SPP mode light is radiated unevenness on the surface of the metal electrode. It can be re-radiated as propagating light and extracted. Furthermore, the light extracted from the surface of the metal electrode can be refracted in the front direction of the substrate at the interface between the lens structure of the substrate and the atmosphere to increase the amount of light extracted in the front direction of the substrate.
  • FIG. 4 is a schematic cross-sectional view for explaining an example of the organic EL element according to the third embodiment of the present invention.
  • 4A can be said to be a configuration in which the lens structure 22a protrudes toward the metal electrode 24 (a configuration in which the organic layer 23 has a concave lens structure, or a configuration in which a lens structure is provided at the interface between the transparent electrode 22 and the organic layer 23).
  • the lens structure 23a (the transparent electrode 22 has a concave lens structure, and can also be said to have a lens structure at the interface between the transparent electrode 22 and the organic layer 23) is the transparent electrode 22. It is the structure which protrudes to the side.
  • the substrate 21 may be provided on the side opposite to the organic layer of the transparent electrode as shown by a solid line in FIG. 4, or may be provided on the side opposite to the organic layer of the metal electrode as shown by a two-dot chain line. But you can.
  • the organic EL element 30 shown in FIG. 4A (when the substrate 21 has a configuration indicated by a solid line) includes a transparent electrode 22, an organic layer 23 including a light emitting layer, and a metal electrode 24 in this order on the substrate 21.
  • the organic EL element is configured to extract light from the transparent electrode side to the outside.
  • the metal electrode 24 has a plurality of radiation uneven portions 24a periodically arranged in at least one direction on the surface 24A on the organic layer side.
  • the transparent electrode 22 includes a lens structure (third lens structure) 22a that has a refractive index higher than that of the organic layer and protrudes toward the organic layer at the interface with the organic layer. Are arranged at the same period as the period of the radiation uneven part 24a in the direction in which the radiation uneven part 24a is periodically arranged.
  • the refractive index of an organic layer means the refractive index of the highest layer among all the layers including a light emitting layer (organic light emitting layer).
  • This organic EL element can be applied to both a top emission type and a bottom emission type organic EL element.
  • the same material as that of the substrate 1 of the first embodiment can be used as the material of the substrate 21.
  • the thickness of the substrate 1 depends on the required mechanical strength and is not particularly limited, but is preferably 0.01 mm to 10 mm, more preferably 0.05 mm to 2 mm.
  • an opaque substrate can be used in order to be applied to the top emission type.
  • a substrate made of a material such as an alloy or stainless steel, or a substrate usually used in other top emission type organic EL elements can be used.
  • the transparent electrode 22 has a refractive index higher than that of the organic layer 23.
  • the transparent electrode 22 includes a lens structure 22a that protrudes toward the organic layer at the interface with the organic layer 23, and a layered portion 22b that is formed integrally with the lens structure 22a on the substrate side of the lens structure 22a.
  • the refractive index of the transparent electrode 22 is preferably higher than the refractive index of the organic layer 23 by 0.2 or more. The reason why the difference in refractive index is 0.2 or more is that light is refracted at the interface to exhibit a sufficient light collecting effect as a lens.
  • the metal electrode 24 has a plurality of radiation uneven portions 24a periodically arranged in at least one direction on the surface 24A on the organic layer side.
  • the period of at least one direction of 24a is the same as the period of one direction of the lens structure 22a.
  • the configuration of the radiation uneven portion 24a can be the same as that of the organic EL element of the first embodiment.
  • the metal electrode 14 may be the same material and thickness as in the first embodiment.
  • the organic layer 23 is disposed between the lens structure 22a of the transparent electrode 22 and the metal electrode 24, and has a concave portion 23c corresponding to the shape of the lens structure 22a of the transparent electrode 22, and a concave portion on the metal electrode side of the concave portion 23c.
  • 23 a having a layered portion 23 d formed integrally with 23 a and a convex portion 23 e having a shape complementary to the shape of the radiation concave-convex portion 24 a of the metal electrode 24.
  • the shape of the portion complementary to the radiation uneven portion 24a is the convex portion 23e, but may be other shapes as long as it is complementary to the shape of the radiation uneven portion 24a, and the radiation uneven portion 24a.
  • the organic layer 23 can be made of the same material as in the first embodiment.
  • the interface 29 between the transparent electrode 22 and the organic layer 23 has a convex curved surface of the lens structure 22a that protrudes toward the organic layer.
  • FIG. 4A The light propagation method indicated by the arrows in FIG. 5 is schematically shown for easy understanding of the principle of the effect.
  • FIGS. 5A and 5B the layers are the same as those in FIGS. 4A and 4B, respectively.
  • the light traveling toward the metal electrode 24 (arrow B1) is captured as SPP mode light on the surface 24A of the metal electrode 24.
  • the trapped light travels along the surface 24A (arrow B2) and is re-emitted as propagating light at the radiating uneven portions 24a 1 (24a) (arrows B3 and B4).
  • the light that enters the organic layer 23 and reaches the interface between the concave portion 23c 1 (23c) of the organic layer 23 and the lens structure 22a 1 (22a) of the transparent electrode 22 has a lower refractive index than that of the transparent electrode.
  • the lens structure 22a 1 (22a) (or the concave portion 23c 1 (23c)) is refracted toward the center line CC side and taken out of the element (arrows B5 and B6).
  • the center of the lens structure 22a is obtained.
  • the light is refracted toward the line CC and is taken out of the substrate 21. Thereby, the extraction of light in the front direction of the substrate increases.
  • the SPP mode light is radiated unevenness on the surface of the metal electrode. It can be re-radiated as propagating light and extracted. Further, the light extracted from the surface of the metal electrode can be refracted in the front direction of the substrate at the interface between the lens structure of the transparent electrode and the organic layer to increase the amount of light extracted in the front direction of the substrate.
  • the description given above with reference to FIGS. 4A and 5A is for the case where the refractive index of the transparent electrode 22 is higher than the refractive index of the organic layer 23.
  • the organic EL element shown in FIG. 4B has a configuration in which the protruding direction of the lens structure faces the opposite side with respect to the organic EL element shown in FIG.
  • the organic EL element shown in FIG. 5B the lens action (condensing function) similar to the lens action shown in FIG. That is, the same light extraction effect as that of the organic EL element shown in FIG.
  • the organic layer 23 includes a lens structure (first lens structure) 23 a that has a refractive index higher than that of the transparent electrode 22 and protrudes toward the substrate side at the interface with the transparent electrode 22.
  • the lens structure 23a is arranged with the same period as the period of the radiation uneven portion 24a in the direction in which the radiation uneven portion 24a is periodically arranged.
  • the refractive index of the transparent electrode 22 is preferably 0.2 or more lower than the refractive index of the organic layer 23. The reason why the difference in refractive index is 0.2 or more is that light is refracted at the interface to exhibit a sufficient light collecting effect as a lens.
  • Such a relationship between the refractive indexes of the transparent electrode 22 and the organic layer 23 can be obtained, for example, by using a conductive polymer such as PEDOT: PSS as the transparent electrode 22.
  • the organic EL element of this embodiment even if the light emitted from the light emitting layer included in the organic layer is captured as SPP mode light on the surface of the metal electrode, the SPP mode light is radiated unevenness on the surface of the metal electrode. It can be re-radiated as propagating light and extracted. Further, the light extracted from the surface of the metal electrode can be refracted in the front direction of the substrate by the lens structure at the interface between the transparent electrode 22 and the organic layer 23 to increase the amount of light extracted in the front direction of the substrate. .
  • FIG. 6 is a schematic cross-sectional view for explaining a modified example of the organic EL element according to the first to third embodiments of the present invention.
  • the organic EL element 40 shown in FIG. 6 includes a transparent electrode 32, an organic layer 33 including a light emitting layer, and a metal electrode 34 in this order on a substrate 31, and extracts light from the transparent electrode 32 side to the outside.
  • the organic EL element 40 is configured.
  • the metal electrode 34 has a plurality of radiation concavo-convex portions 34a periodically disposed in at least one direction on the surface 34A on the organic layer side.
  • the transparent electrode 32 has a higher refractive index than the refractive index of the organic layer 33 and the substrate 31, and a lens structure (third lens structure) 32b that protrudes toward the organic layer at the interface with the organic layer 33.
  • a lens structure (first lens structure) 32a protruding toward the substrate is provided at the interface with the substrate 1.
  • the 1st lens structure 32a and / or the 3rd lens structure 32b are arrange
  • the substrate 31 includes a lens structure (second lens structure) 31a that protrudes outward on the surface opposite to the transparent electrode, but includes a second lens structure 31a. It does not have to be.
  • the first lens structure 32a, the second lens structure 31a, and the third lens structure 32b preferably have at least two center lines CC that coincide.
  • the description given above with reference to FIG. 6 is for the case where the refractive index of the transparent electrode 32 is higher than the refractive index of the organic layer 33 and the refractive index of the substrate 31.
  • the organic layer 33 includes a lens structure that protrudes toward the transparent electrode at the interface with the transparent electrode 32. Further, by providing the substrate 31 with a lens structure that protrudes toward the transparent electrode at the interface with the transparent electrode 32, the same light extraction effect as that of the organic EL element described in FIG. 6 can be obtained.
  • the relationship between the refractive indexes of the transparent electrode 32, the organic layer 33, and the substrate 31 is such that a conductive polymer such as PEDOT: PSS is used as the transparent electrode 32 or a high refractive index substrate is used as the substrate 31. happenss when.
  • the light extraction function in the front direction of the substrate is increased by performing the light collecting function by the lens structure included in the organic EL elements according to the first to third embodiments described above. be able to.
  • FIG. 7 is a schematic cross-sectional view for explaining an example of the organic EL element according to the fourth embodiment of the present invention.
  • FIG. 7A illustrates a configuration in which the lens structure 46a protrudes toward the substrate 41 (a configuration in which the first dielectric layer 45 includes a concave lens structure, an interface between the first dielectric layer 45 and the second dielectric layer 46). It can also be said that the lens structure has a lens structure.
  • 7B can be said to be a lens structure 45a (a configuration in which the second dielectric layer 46 has a concave lens structure, and a configuration in which a lens structure is provided at the interface between the first dielectric layer 45 and the second dielectric layer 46). ) Protrudes toward the metal electrode 44 side.
  • the substrate 41 may be configured to be provided on the side opposite to the organic layer of the first dielectric layer as shown by a solid line in FIG. 7, or the side opposite to the organic layer of the metal electrode as shown by a two-dot chain line.
  • the structure provided for may be used.
  • An organic EL element 50 shown in FIG. 7A (when the substrate 41 has a configuration indicated by a solid line) includes a transparent electrode 42, an organic layer 43 including a light emitting layer, and a metal electrode 44 in this order on the substrate 41.
  • the organic EL element is configured to extract light from the transparent electrode 42 side to the outside.
  • the metal electrode 44 has a plurality of radiation uneven portions 44a periodically arranged in at least one direction on the surface 44A on the organic layer side.
  • a first dielectric layer 45 and a second dielectric layer 46 are sequentially provided from the substrate side, and the second dielectric layer 46 has a refractive index of 0.1 and 0.1.
  • the second dielectric layer 46 has a higher refractive index than the first dielectric layer 45 (the difference in refractive index is 0.2 or more), and the interface between the first dielectric layer 45 and the second dielectric layer 46 is the substrate 41.
  • a lens structure (fourth lens structure) 46a protruding to the side is provided.
  • the lens structure 46a is arranged with the same period as the period of the radiation uneven part 44a in the direction in which the radiation uneven part 44a is periodically arranged.
  • the reason why the second dielectric 46 has a refractive index difference of 0.1 or less from the transparent electrode 42 or higher than the refractive index of the transparent electrode 42 is that total reflection occurs when light enters the second dielectric from the transparent electrode 42. This is to prevent it from happening. Further, the reason that the difference in refractive index between the first dielectric layer and the second dielectric layer is 0.2 or more is to refract light at the interface to exhibit a sufficient light collecting effect as a lens.
  • This organic EL element can be applied to both a top emission type and a bottom emission type organic EL element.
  • the same material and thickness of the substrate 41 as those of the substrate of the first embodiment can be used.
  • an opaque substrate such as a metal substrate or a substrate normally used in other top emission type organic EL elements is used. it can.
  • the transparent electrode 42 can be made of the same material as the transparent electrode material of the first embodiment.
  • the thickness can be the same as the thickness of the layered portion 2d of the transparent electrode 2 of the first embodiment.
  • the metal electrode 44 has a plurality of radiation uneven portions 44a periodically arranged in at least one direction on the surface 44A on the organic layer side.
  • the period of at least one direction of the radiation uneven portion 44 a is the same as the period of one direction of the lens structure 46 a of the second dielectric layer 46.
  • the configuration of the radiation uneven portion 44a can be the same as that of the organic EL element of the first embodiment.
  • the metal electrode 44 may be the same material and thickness as those in the first embodiment.
  • the organic layer 43 is disposed between the transparent electrode 42 and the metal electrode 44, and has a layered portion 43d and a convex portion 43e having a shape complementary to the shape of the radiation uneven portion 44a of the metal electrode 44.
  • the same material and thickness as those in the first embodiment can be used.
  • the first dielectric layer 45 is disposed between the substrate 41 and the second dielectric layer 46 and has a recess 45 c corresponding to the lens structure 46 a of the second dielectric layer 46.
  • the first dielectric layer 45 has a refractive index similar to the refractive index of the substrate 41 (for example, a refractive index difference of 0.1 or less) or a refractive index of the substrate 41 so that total reflection does not occur at the interface with the substrate 41. It is preferable to have a refractive index lower than the refractive index.
  • the material of the first dielectric layer 45 is not particularly limited. For example, silicon oxide such as spin-on-glass (SOG) (refractive index: 1.1 to 2.0) or silica (SiO 2 ) is used.
  • the first dielectric layer 45 needs to be thicker than the lens structure 46a of the second dielectric layer 46.
  • the second dielectric layer 46 is disposed between the first dielectric layer 45 and the transparent electrode 42, is higher than the refractive index of the first dielectric layer 45 (refractive index difference is 0.2 or more), and It has a refractive index difference of 0.1 or less or a refractive index higher than that of the transparent electrode. Furthermore, a lens structure 46 a that protrudes toward the substrate is provided at the interface with the first dielectric layer 45. By providing the lens structure 46a, it is possible to condense the SPP mode light re-radiated as the propagation light from the radiating portion uneven portion on the front side.
  • the material of the second dielectric layer 46 is not limited.
  • the thickness of the second dielectric layer 46 needs to be thicker than the desired lens structure 46a.
  • the interface 49 between the first dielectric layer 45 and the second dielectric layer 46 has a convex curved surface of the lens structure 46a of the second dielectric layer 46 protruding to the substrate side, and the first dielectric layer 45 has a concave portion 45 c having a shape complementary to the shape of the lens structure 46 a of the second dielectric layer 46.
  • the SPP mode light captured on the surface of the metal electrode Is re-radiated as propagating light at the radiation uneven portion 44a on the surface of the metal electrode and taken out, passes through the organic layer 43 and the transparent electrode 42, and enters the second dielectric layer 46.
  • the light reaching the interface between the lens structure 46a 1 (46a) of the second dielectric layer 46 and the recess 45c 1 (45c) of the first dielectric layer 45 is higher than the refractive index of the first dielectric layer 45.
  • the light is refracted toward the center line CC side of the lens structure 46a 1 (46a).
  • the lens structure 46a is refracted toward the center line CC and is taken out of the substrate 41. Thereby, the extraction of light in the front direction of the substrate increases.
  • the description given above with reference to FIG. 7A is for the case where the refractive index of the second dielectric layer 46 is higher than the refractive index of the first dielectric layer 45.
  • the organic EL element shown in FIG. 7B has a configuration in which the protruding direction of the lens structure faces the opposite side with respect to the organic EL element shown in FIG. In this configuration, when the materials of the first dielectric layer 45 and the second dielectric layer 46 are selected so that the refractive index of the first dielectric layer 45 is higher than the refractive index of the second dielectric layer 46.
  • the organic EL element shown in FIG. 7 (b) exhibits the same lens action (condensing function) as the lens action in the organic EL element shown in FIG. 7 (a), and the organic EL element shown in FIG. 7 (a). The same light extraction effect can be obtained.
  • the first dielectric layer 45 has a refractive index higher than the refractive index of the second dielectric layer 46 (with a refractive index difference of 0.2 or more) and the second dielectric layer 46.
  • a lens structure (fourth lens structure) 45a that protrudes toward the metal electrode is provided at the interface, and the lens structure 45a is arranged at the same period as the period of the radiation uneven part 44a in the direction in which the radiation uneven part 44a is periodically arranged.
  • the relationship between the refractive indexes of the first dielectric layer 45 and the second dielectric layer 46 is, for example, that a conductive polymer such as PEDOT: PSS is used as the transparent electrode 42 and a high refractive index substrate is used as the substrate 41. It can be obtained by using.
  • the organic EL element of this embodiment even if the light emitted from the light emitting layer included in the organic layer is captured as SPP mode light on the surface of the metal electrode, the SPP mode light is radiated unevenness on the surface of the metal electrode. It can be re-radiated as propagating light and extracted. Further, the light extracted from the surface of the metal electrode is refracted in the front direction of the substrate by the lens structure at the interface between the second dielectric layer and the first dielectric layer, thereby increasing the amount of light extracted in the front direction of the substrate. Can be made.
  • FIG. 8 is a schematic cross-sectional view for explaining an example of the organic EL element according to the fifth embodiment of the present invention.
  • FIG. 8A shows a configuration in which the lens structure 55a protrudes toward the substrate 51 (a configuration in which the substrate 51 has a concave lens structure, or a configuration in which a lens structure is provided at the interface between the substrate 51 and the dielectric layer 55). is there.
  • a lens structure 51a (a configuration in which the dielectric layer 55 has a concave lens structure, a configuration in which a lens structure is provided at the interface between the substrate 51 and the dielectric layer 55) protrudes toward the metal electrode 54 side. It is the structure to do.
  • the 8A includes a transparent electrode 52, an organic layer 53 including a light emitting layer, and a metal electrode 54 in this order on a substrate 51, and transmits light from the transparent electrode 52 side to the outside.
  • This is an organic EL element configured to be taken out.
  • the metal electrode 54 has a plurality of radiation uneven portions 54a periodically arranged in at least one direction on the surface 54A on the organic layer side.
  • a dielectric layer 55 is provided between the substrate 51 and the transparent electrode 52.
  • the dielectric layer 55 has a refractive index difference of 0.1 or less or a refractive index higher than that of the transparent electrode 52 and a refractive index higher than that of the substrate 51 (the refractive index difference is 0). .2 or more).
  • the dielectric layer 55 includes a lens structure (fifth lens structure) 55 a that protrudes toward the substrate at the interface with the substrate 51.
  • the lens structure 55a is arranged with the same period as the period of the radiation uneven portion 54a in the direction in which the radiation uneven portion 54a is periodically arranged.
  • the reason why the dielectric layer 55 has a refractive index difference of 0.1 or less with respect to the transparent electrode 52 or a refractive index higher than that of the transparent electrode 52 is that total reflection occurs when light enters the dielectric layer 55 from the transparent electrode 52. This is to prevent it from happening.
  • the reason why the difference in refractive index between the dielectric layer 55 and the substrate 51 is 0.2 or more is to refract light at the interface to exhibit a sufficient light collecting effect as a lens.
  • This organic EL element is also a bottom emission type organic EL element, like the organic EL element of the first embodiment. Since the concave portion 51c corresponding to the lens structure 55a of the dielectric layer 55 is provided, the same material and thickness of the substrate 51 as those of the substrate of the first embodiment can be used.
  • the same material as the transparent electrode material of the first embodiment can be used.
  • the thickness can be the same as the thickness of the layered portion 2d of the transparent electrode 2 of the first embodiment.
  • the metal electrode 54 has a plurality of radiation uneven portions 54a periodically arranged in at least one direction on the surface 54A on the organic layer side.
  • the period in at least one direction of the radiation uneven portion 54 a is the same as the period in one direction of the lens structure 55 a of the dielectric layer 55.
  • the configuration of the radiation uneven portion 54a can be the same as that of the organic EL element of the first embodiment.
  • the metal electrode 54 may be the same material and thickness as in the first embodiment.
  • the organic layer 53 is disposed between the transparent electrode 52 and the metal electrode 54, and has a layered portion 53d and a convex portion 53e having a shape complementary to the shape of the radiation uneven portion 54a of the metal electrode 54.
  • the same material and thickness as those in the first embodiment can be used.
  • the dielectric layer 55 is disposed between the substrate 51 and the transparent electrode 52, has a refractive index that is less than the refractive index difference of the transparent electrode 52 and 0.1 or less, and is higher than the refractive index of the substrate 51. It has a refractive index (refractive index difference is 0.2 or more). Further, a lens structure 55 a that protrudes toward the substrate side is provided at the interface with the substrate 51.
  • the material of the dielectric layer 55 the same materials as those mentioned for the first dielectric layer 45 of the fourth embodiment can be used, but it is necessary to satisfy the above-mentioned refractive index condition. .
  • the thickness of the dielectric layer 55 needs to be thicker than the desired lens structure 55a.
  • the interface 59 between the substrate 51 and the dielectric layer 55 has a convex curved surface of the lens structure 55a of the dielectric layer 55 protruding to the substrate side.
  • the substrate 51 has a concave portion 51 c corresponding to the lens structure 55 a of the dielectric layer 55.
  • the SPP mode light captured on the surface of the metal electrode Is re-radiated as propagating light at the radiation uneven portion 54 a on the surface of the metal electrode and extracted, passes through the organic layer 53 and the transparent electrode 52, and enters the dielectric layer 55.
  • the light reaching the interface between the lens structure 55a 1 (55a) of the dielectric layer 55 and the concave portion 51c 1 (51c) of the substrate 51 is transmitted from the dielectric layer 55 having a refractive index higher than that of the substrate 51.
  • the lens structure 55a 1 (55a) is refracted toward the center line CC side.
  • the lens structure 55a Even if the light re-radiated as the propagation light by the radiation uneven portion 54a of the metal electrode 54 enters the lens structure 55a in a direction away from the center line CC of the lens structure 55a of the dielectric layer 55, the lens structure The light is refracted toward the center line CC of 55a and taken out of the substrate 51. Thereby, the extraction of light in the front direction of the substrate increases.
  • the description given above with reference to FIG. 8A is for the case where the refractive index of the dielectric layer 55 is higher than the refractive index of the substrate 51.
  • the organic EL element shown in FIG. 8B has a configuration in which the protruding direction of the lens structure faces the opposite side with respect to the organic EL element shown in FIG.
  • FIG. 8 (b) when the materials of the substrate 51 and the dielectric layer 55 are selected so that the refractive index of the substrate 51 is higher than the refractive index of the dielectric layer 55 (the refractive index difference is 0.2 or more), FIG.
  • the organic EL element shown in FIG. 8 (b) exhibits the same lens action (condensing function) as that of the organic EL element shown in FIG. 8 (a), and is the same as the organic EL element shown in FIG. 8 (a). The light extraction effect can be obtained.
  • the dielectric layer 55 includes a lens structure (fifth lens structure) 51a having a refractive index lower than that of the substrate 51 and protruding toward the metal electrode at the interface with the substrate 51.
  • the lens structure 51a is arranged with the same period as the period of the radiation uneven part 54a in the direction in which the radiation uneven part 54a is periodically arranged.
  • Such a relationship between the refractive index of the dielectric layer 55 and the substrate 51 is obtained, for example, by using a conductive polymer such as PEDOT: PSS as the transparent electrode 52 or by using a high refractive index substrate as the substrate 51. be able to.
  • the organic EL element of this embodiment even if the light emitted from the light emitting layer included in the organic layer is captured as SPP mode light on the surface of the metal electrode, the SPP mode light is radiated unevenness on the surface of the metal electrode.
  • the light extracted from the surface of the metal electrode can be refracted by the lens structure at the interface between the dielectric layer and the substrate and refracted in the front direction of the substrate. The amount of light extracted to the can be increased.
  • FIG. 9 is a schematic cross-sectional view for explaining an example of the organic EL element according to the sixth embodiment of the present invention.
  • 9A shows a configuration in which the lens structure 62a protrudes toward the substrate 61 (a configuration in which the dielectric layer 65 has a concave lens structure, and a configuration in which a lens structure is provided at the interface between the transparent electrode 62 and the dielectric layer 65). I can say).
  • a lens structure 65a (a structure in which the transparent electrode 62 has a concave lens structure, a structure having a lens structure at the interface between the transparent electrode 62 and the dielectric layer 65) protrudes toward the metal electrode 64 side. It is the structure to do.
  • the substrate 61 may be provided on the side opposite to the organic layer of the dielectric layer as shown by a solid line in FIG. 9, or may be provided on the side opposite to the organic layer of the metal electrode as shown by a two-dot chain line. It may be configured.
  • the organic EL element 70 shown in FIG. 9A (when the substrate 61 is configured by a solid line) includes a transparent electrode 62, an organic layer 63 including a light emitting layer, and a metal electrode 64 in this order on the substrate 61.
  • the organic EL element is configured to extract light from the transparent electrode side to the outside.
  • the metal electrode 64 has a plurality of radiation uneven portions 64a periodically arranged in at least one direction on the surface 64A on the organic layer side.
  • a dielectric layer 65 is provided between the substrate 61 and the transparent electrode 62, and the transparent electrode 62 has a refractive index difference of 0.1 or less or a refractive index higher than that of the organic layer 63. Further, the transparent electrode 62 has a refractive index higher than the refractive index of the dielectric layer 65 (refractive index difference is 0.2 or more).
  • the transparent electrode 62 includes a lens structure (sixth lens structure) 62 a that protrudes toward the substrate at the interface with the dielectric layer 65.
  • the lens structure 62a is arranged with the same period as the period of the radiation uneven part 64a in the direction in which the radiation uneven part 64a is periodically arranged.
  • the reason why the dielectric layer 62 has a refractive index difference of 0.1 or less from the organic layer 63 or a higher refractive index than the organic layer 63 is that total reflection occurs when light enters the dielectric layer 62 from the organic layer 63. This is to prevent it from happening.
  • the reason why the difference in refractive index between the dielectric layer 65 and the transparent electrode 62 is 0.2 or more is to refract light at the interface to exhibit a sufficient light collecting effect as a lens.
  • This organic EL element can be applied to both a top emission type and a bottom emission type organic EL element.
  • the same material and thickness of the substrate 61 as those of the substrate of the first embodiment can be used.
  • an opaque substrate such as a metal substrate or a substrate normally used in other top emission type organic EL elements is used. it can.
  • the transparent electrode 62 has a refractive index higher than the refractive index of the dielectric layer 65 (refractive index difference is 0.2 or more).
  • the transparent electrode 62 includes a lens structure 62a that protrudes toward the substrate at the interface with the dielectric layer 65, and a layered portion 62d that is formed integrally with the lens structure 62a on the organic layer side of the lens structure 62a.
  • the transparent electrode 62 the same material and configuration as those of the transparent electrode 2 of the first embodiment can be used.
  • the interface 69 between the transparent electrode 62 and the dielectric layer 65 has a convex curved surface of the lens structure 62a protruding toward the substrate, and the low dielectric layer 65 is complementary to the shape of the lens structure 62a of the transparent electrode 62.
  • a concave portion 65c having a typical shape is provided.
  • the metal electrode 64 has a plurality of radiation uneven portions 64a periodically arranged in at least one direction on the surface 64A on the organic layer side.
  • a period in at least one direction of the radiation uneven portion 64 a is the same as a period in one direction of the lens structure 62 a of the transparent electrode 62.
  • the configuration of the radiation uneven portion 64a can be the same as that of the organic EL element of the first embodiment.
  • the metal electrode 64 may be the same material and thickness as in the first embodiment.
  • the organic layer 63 is disposed between the transparent electrode 62 and the metal electrode 64, and has a layered portion 63d and a convex portion 63e having a shape complementary to the shape of the radiation uneven portion 64a of the metal electrode 64.
  • the same material and thickness as those in the first embodiment can be used.
  • the dielectric layer 65 is disposed between the substrate 61 and the transparent electrode 62 and has a refractive index lower than the refractive index of the transparent electrode 62 (with a refractive index difference of 0.2 or more).
  • a recess 65c corresponding to the structure 62a is provided.
  • the dielectric layer 65 has a refractive index comparable to the refractive index of the substrate 61 (for example, a refractive index with a refractive index difference of 0.1 or less) or the substrate 61 so that total reflection does not occur at the interface with the substrate 61. It is preferable to have a refractive index lower than the refractive index.
  • the same materials as those mentioned for the first dielectric layer 45 of the fourth embodiment can be used, but it is necessary to satisfy the above-mentioned refractive index condition. .
  • the thickness of the dielectric layer 65 needs to be greater than the height of the lens structure 62 a of the transparent electrode 62.
  • the SPP mode light captured on the surface of the metal electrode Is re-radiated as propagating light at the radiation uneven portion 64 a on the surface of the metal electrode and extracted, passes through the organic layer 63 and enters the transparent electrode 62.
  • the light reaching the interface between the lens structure 62 a 1 (62 a) of the transparent electrode 62 and the recess 65 c 1 (65 c) of the dielectric layer 65 has a refractive index higher than that of the dielectric layer 65.
  • the organic EL element shown in FIG. 9B has a configuration in which the protruding direction of the lens structure faces the opposite side with respect to the organic EL element shown in FIG.
  • the material of the dielectric layer 65 and the transparent electrode 62 is selected so that the refractive index of the dielectric layer 65 is higher than the refractive index of the transparent electrode 62 (the refractive index difference is 0.2 or more).
  • the organic EL element shown in FIG. 9B exhibits a lens action (condensing function) similar to the lens action in the organic EL element shown in FIG. That is, the same light extraction effect as that of the organic EL element shown in FIG. 9A can be obtained.
  • the dielectric layer 65 has a lens structure (sixth lens structure) 65 a having a refractive index higher than that of the transparent electrode 62 and protruding toward the metal electrode at the interface with the transparent electrode 62.
  • the lens structure 65a is arranged with the same period as the period of the radiation uneven part 64a in the direction in which the radiation uneven part 64a is periodically arranged.
  • Such a relationship between the refractive index of the dielectric layer 65 and the transparent electrode 62 can be obtained, for example, by using a conductive polymer such as PEDOT: PSS as the transparent electrode 62.
  • the organic EL element of this embodiment even if the light emitted from the light emitting layer included in the organic layer is captured as SPP mode light on the surface of the metal electrode, the SPP mode light is radiated unevenness on the surface of the metal electrode. It can be re-radiated as propagating light and extracted. Furthermore, the light extracted from the surface of the metal electrode can be refracted in the front direction of the substrate by the lens structure at the interface between the transparent electrode and the dielectric layer to increase the amount of light extracted in the front direction of the substrate.
  • FIG. 10 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 80 according to the seventh embodiment of the present invention includes, on a substrate 71, a transparent electrode 72, an organic layer 73 including a light emitting layer, and a metal electrode 74 in order, and from the transparent electrode side to the outside. It is an organic EL element configured to extract light.
  • the metal electrode 74 has a plurality of radiation uneven portions 74a periodically disposed in at least one direction on the surface 74A on the organic layer side.
  • a dielectric layer 75 is provided on the opposite side of the substrate 71 from the transparent electrode 72, and the dielectric layer 75 has a refractive index difference of 0.1 or less from the refractive index of the substrate 71 or a refractive index higher than that of the substrate.
  • the dielectric layer 75 includes a lens structure (seventh lens structure) 75a that protrudes on the opposite side of the substrate.
  • the lens structure 75a is arranged with the same period as the period of the radiation uneven part 74a in the direction in which the radiation uneven part 74a is periodically arranged.
  • the dielectric layer 75 has a refractive index difference of 0.1 or less than that of the substrate 71 or a refractive index higher than that of the substrate 71 is that it does not cause total reflection when light enters the dielectric layer 75 from the substrate 71. is there.
  • this organic EL element is also a bottom emission type organic EL element like the organic EL element of the first embodiment, the material and thickness of the substrate 71 are the same as those of the substrate 1 of the first embodiment. Can be used.
  • the same material as the transparent electrode material of the first embodiment can be used.
  • the thickness can be the same as the thickness of the layered portion 2d of the transparent electrode 2 of the first embodiment.
  • the metal electrode 74 has a plurality of radiation uneven portions 74a periodically arranged in at least one direction on the surface 74A on the organic layer side.
  • the period in at least one direction of the radiation uneven portion 74 a is the same as the period in one direction of the lens structure 75 a of the dielectric layer 75.
  • the configuration of the radiation uneven portion 74a can be the same as that of the organic EL element of the first embodiment.
  • the metal electrode 74 may be the same material and thickness as those in the first embodiment.
  • the organic layer 73 is disposed between the transparent electrode 72 and the metal electrode 74, and is complementary to the shape of the layered portion 73 d and the radiation uneven portion 74 a of the metal electrode 74. And a convex portion 73e having a shape.
  • the same material and thickness as those in the first embodiment can be used.
  • the dielectric layer 75 includes a lens structure 75 a that has a refractive index difference of 0.1 or less or a refractive index higher than that of the substrate 71 and protrudes on the opposite side of the substrate 71.
  • a dielectric layer 75 which is a layer provided on the opposite side of the substrate 71 from the transparent electrode 72, includes a lens structure 75 a that protrudes to the atmosphere side.
  • the material of the dielectric layer 75 the same materials as those mentioned for the first dielectric layer 45 of the fourth embodiment can be used, but it is necessary to satisfy the above-mentioned refractive index condition. .
  • the SPP mode light captured on the surface of the metal electrode Is re-radiated by the radiation uneven portion 74 a on the surface of the metal electrode and taken out, passes through the organic layer 73, the transparent electrode 72 and the substrate 71 and enters the dielectric layer 75. Then, the light that reaches the interface between the lens structure 75a 1 (75a) of the dielectric layer 75 and the atmosphere exits from the dielectric layer 75 having a refractive index higher than that of the atmosphere into the atmosphere. It refracts toward the center line CC side of 75a 1 (75a).
  • the lens structure 75a Even if the light re-radiated as the propagation light by the radiation uneven portion 74a of the metal electrode 74 enters the lens structure 75a in a direction away from the center line CC of the lens structure 75a of the dielectric layer 75, the lens structure The light is refracted toward the center line CC of 75a and taken out of the element. Thereby, the extraction of light in the front direction of the substrate increases.
  • the organic EL element of this embodiment even if the light emitted from the light emitting layer included in the organic layer is captured as SPP mode light on the surface of the metal electrode, the SPP mode light is radiated unevenness on the surface of the metal electrode. It can be re-radiated as propagating light and extracted. Furthermore, the light extracted from the surface of the metal electrode can be refracted in the front direction of the substrate by the lens structure at the interface between the dielectric layer and the atmosphere, and the amount of light extracted in the front direction of the substrate can be increased.
  • FIG. 11 is a cross-sectional schematic diagram for demonstrating an example of the organic EL element which concerns on the 8th Embodiment of this invention.
  • FIG. 11 shows a configuration in which a lens structure 83a (a configuration in which the transparent conductive layer 85 has a concave lens structure, a configuration in which a lens structure is provided at the interface between the organic layer 83 and the transparent conductive layer 85) protrudes toward the substrate 81. is there.
  • the substrate 81 may be provided on the side opposite to the organic layer of the transparent electrode as shown by a solid line in FIG. 11, or may be provided on the side opposite to the organic layer of the metal electrode as shown by a two-dot chain line. But you can.
  • An organic EL element 100 shown in FIG. 11 (when the substrate 81 has a configuration indicated by a solid line) includes a transparent electrode 82, an organic layer 83 including a light emitting layer, and a metal electrode 84 on the substrate 81 in order.
  • the organic EL element is configured to extract light from the electrode 82 side to the outside.
  • the metal electrode 84 has a plurality of radiation uneven portions 84a periodically disposed in at least one direction on the surface 84A on the organic layer side.
  • a transparent conductive layer 85 is provided between the transparent electrode 82 and the organic layer 83, and the transparent conductive layer 85 has a refractive index lower than the refractive index of the organic layer 83 (refractive index difference is 0.2 or more).
  • the organic layer 83 includes a lens structure (eighth lens structure) 83a that protrudes toward the substrate at the interface with the transparent conductive layer 85, and the lens structure 83a emits in the direction in which the radiation uneven portions 84a are periodically arranged. It arrange
  • the difference in refractive index between the transparent conductive layer 85 and the organic layer 83 is 0.2 or more is to refract light at the interface to exhibit a sufficient light collecting effect as a lens.
  • the refractive index of an organic layer means the refractive index of the highest layer among all the layers including a light emitting layer (organic light emitting layer).
  • This organic EL element can also be applied to both a top emission type and a bottom emission type organic EL element.
  • the same material and thickness of the substrate 81 as those of the substrate 1 of the first embodiment can be used.
  • an opaque substrate such as a metal substrate or a substrate normally used in other top emission type organic EL elements is used. it can.
  • the same material as the transparent electrode material of the first embodiment can be used.
  • the thickness it can be set as the same thickness as the layer part 2d of the transparent electrode 2 of 1st Embodiment.
  • the metal electrode 84 has a plurality of radiation concavo-convex portions 84a periodically arranged in at least one direction on the surface 84A on the organic layer side.
  • the period in at least one direction of the radiation uneven portion 84 a is the same as the period in one direction of the lens structure 85 a of the transparent conductive layer 85.
  • the configuration of the radiation uneven portion 84a can be the same as that of the organic EL element of the first embodiment.
  • the metal electrode 84 may be the same material and thickness as those of the other embodiments.
  • the organic layer 83 is disposed between the lens structure 85 a of the transparent conductive layer 85 and the metal electrode 84. It has a lens structure 83a, a layered portion 83d formed integrally with the lens structure 83a, and a convex portion 83e having a shape complementary to the shape of the radiation uneven portion 84a of the metal electrode 84.
  • the shape of the portion complementary to the shape of the radiation uneven portion 84a is a convex shape, but may be other shapes as long as it is complementary to the shape of the radiation uneven portion 84a. It is not necessary to fit (fit) the shape of the radiation uneven portion 84a.
  • the organic layer 83 can be made of the same material as in the other embodiments.
  • the transparent conductive layer 85 has a refractive index lower than the refractive index of the organic layer 83 (with a refractive index difference of 0.2 or more) and is complementary to the shape of the lens structure 83a that protrudes toward the substrate at the interface with the organic layer 83.
  • a concave portion 85c having a simple shape is provided.
  • the transparent conductive layer 85 has a refractive index similar to the refractive index of the transparent electrode 82 (for example, a refractive index with a refractive index difference of 0.1 or less) or is transparent so that total reflection does not occur at the interface with the substrate 81. It is preferable to have a refractive index lower than that of the electrode 82.
  • the material of the transparent conductive layer 85 As the material of the transparent conductive layer 85, the same materials as those mentioned for the first dielectric layer 45 of the fourth embodiment can be used, but it is necessary to satisfy the above-mentioned refractive index condition. . Specific examples of the material of the transparent conductive layer 85 include PEDOT: PSS (typical refractive index 1.5).
  • the transparent conductive layer 85 needs to be thicker than the desired lens structure 85a.
  • the interface 89 between the organic layer 83 and the transparent conductive layer 85 has a convex curved surface of the lens structure 83a of the organic layer 83 protruding to the substrate side.
  • the transparent conductive layer 85 has a concave portion 85 c having a shape complementary to the shape of the lens structure 83 a of the organic layer 83.
  • the SPP mode light captured on the surface of the metal electrode Is re-radiated as propagating light at the radiation uneven portion 84 a on the surface of the metal electrode and extracted, passes through the organic layer 83 and enters the transparent conductive layer 85.
  • the light reaching the interface between the lens structure 83a 1 (83a) of the organic layer 83 and the concave portion 85c 1 (85c) of the transparent conductive layer 85 has a refractive index lower than the refractive index of the organic layer 83 from the organic layer 83.
  • the organic EL element of this embodiment even if the light emitted from the light emitting layer included in the organic layer is captured as SPP mode light on the surface of the metal electrode, the SPP mode light is radiated unevenness on the surface of the metal electrode. It can be re-radiated as propagating light and extracted. Furthermore, the light extracted from the surface of the metal electrode can be refracted in the front direction of the substrate at the interface between the transparent conductive layer and the lens structure of the organic layer to increase the amount of light extracted in the front direction of the substrate.
  • the material used as the transparent electrode 82 is not particularly limited in this case.
  • a material having a refractive index equal to or higher than the refractive index of the dielectric layer 85 is preferable because total reflection hardly occurs at the interface with the transparent conductive layer 85.
  • FIG. 12 is a schematic cross-sectional view for explaining an example of the organic EL element according to the ninth embodiment of the present invention.
  • FIG. 12A shows a configuration in which the lens structure 91a protrudes toward the dielectric layer 95 (a configuration in which the dielectric layer 95 has a concave lens structure, and a configuration in which a lens structure is provided at the interface between the substrate 91 and the dielectric layer 95). It can also be said).
  • FIG. 12B shows a configuration in which a lens structure 95a (a configuration in which the substrate 91 has a concave lens structure, a configuration in which a lens structure is provided at the interface between the substrate 91 and the dielectric layer 95) protrudes toward the substrate 91 side. is there.
  • An organic EL element 100 shown in FIG. 12A includes a transparent electrode 92, an organic layer 93 including a light emitting layer, and a metal electrode 94 in this order on a substrate 91.
  • the organic EL element is configured to extract light from the opposite side of the transparent electrode 92 of the substrate 91 to the outside.
  • the metal electrode 94 has a plurality of radiation uneven portions 94a periodically arranged in at least one direction on the surface 94A on the organic layer side.
  • a dielectric layer 95 is provided on the opposite side of the substrate 91 from the transparent electrode 92, and the dielectric layer 95 has a refractive index lower than the refractive index of the substrate 91 (refractive index difference is 0.2 or more).
  • the substrate 91 includes a lens structure (a ninth lens structure) 91a protruding toward the organic layer at the interface with the dielectric layer 95.
  • the lens structure 91a emits in the direction in which the radiation uneven portions 94a are periodically arranged. It arrange
  • the substrate 91 includes a lens structure 91a protruding toward the dielectric layer 95 at the interface with the dielectric layer 95, and a layered portion 91d integrated with the lens structure 91a on the transparent electrode 92 side of the lens structure 91a. . Since this organic EL element is a bottom emission type organic EL element like the organic EL element of the first embodiment, the material of the substrate 91 and the thickness of the layered portion 91d are the same as those of the first embodiment. A substrate similar to the substrate 1 can be used. In the present embodiment, the substrate 91 includes a lens structure 91a. Therefore, like the organic EL element of the first embodiment, a material that can be processed more accurately is preferable.
  • the same material as the transparent electrode material of the first embodiment can be used.
  • the thickness of the transparent electrode 92 is not particularly limited. For example, it is 10 to 2000 nm, preferably 50 to 1000 nm. If it is thinner than 10 nm, the sheet resistance of the transparent electrode 12 increases. If it is thicker than 2000 nm, the transmittance of the transparent electrode 92 is lowered.
  • the metal electrode 94 has a plurality of radiation uneven portions 94a periodically arranged in at least one direction on the surface 94A on the organic layer side.
  • the period of the radiation uneven portion 94a in at least one direction is the same as the period of the lens structure 91a of the substrate 91 in one direction.
  • the configuration of the radiation uneven portion 94a can be the same as that of the organic EL element of the first embodiment.
  • the metal electrode 94 may be the same material and thickness as those in the first embodiment.
  • the organic layer 93 is disposed between the transparent electrode 92 and the metal electrode 94, and has a layered portion 93a and a convex portion 93e having a shape complementary to the shape of the radiation uneven portion 94a of the metal electrode 94.
  • the same material and thickness as those in the first embodiment can be used.
  • the dielectric layer 95 is disposed on the opposite side of the substrate 91 from the transparent electrode 92, has a refractive index higher than the refractive index of the substrate 91 (refractive index difference is 0.2 or more), and has a substrate at the interface with the substrate 91.
  • a concave portion 95c having a shape complementary to the shape of the 91 lens structure 91a is provided.
  • the material of the dielectric layer 95 the same materials as those mentioned for the first dielectric layer 45 of the fourth embodiment can be used, but it is necessary to satisfy the above-mentioned refractive index condition. .
  • the dielectric layer 95 needs to be thicker than the lens structure 91a of the substrate 91.
  • the SPP mode light captured on the surface of the metal electrode Is re-radiated as propagating light at the radiation uneven portion 94 a on the surface of the metal electrode and extracted, passes through the organic layer 93 and the transparent electrode 92, and enters the substrate 91.
  • the light reaching the interface between the lens structure 91a 1 (91a) of the substrate 91 and the concave portion 95c 1 (95c) of the dielectric layer 95 is transmitted from the substrate 91 having a refractive index higher than that of the dielectric layer 95.
  • the lens structure 91a 1 (91a) is refracted toward the center line CC side.
  • the lens structure lens structure The light is refracted toward the center line CC side of 91a and taken out of the element. Thereby, the extraction of light in the front direction of the substrate increases.
  • the description given above with reference to FIG. 12A is for the case where the refractive index of the dielectric layer 95 is lower than the refractive index of the substrate 91.
  • the dielectric layer 95 and the substrate 91 in this case for example, among the materials exemplified as the material of the first dielectric layer 45 of the fourth embodiment and the substrate 1 of the first embodiment, respectively Any combination that satisfies the refractive index requirements can be used.
  • the organic EL element shown in FIG. 12B has a configuration in which the protruding direction of the lens structure faces the opposite side with respect to the organic EL element shown in FIG.
  • FIG. 12B when the material of the dielectric layer 95 and the substrate 91 is selected so that the refractive index of the dielectric layer 95 is higher than the refractive index of the substrate 91 (the difference in refractive index is 0.2 or more), FIG.
  • the lens action (condensing effect) similar to the lens action of the organic EL element shown in FIG. 12A can be exhibited, and the same light extraction effect as that of the organic EL element shown in FIG.
  • the dielectric layer 95 includes a lens structure (a ninth lens structure) 95a that has a refractive index higher than the refractive index of the substrate 91 and protrudes toward the substrate side at the interface with the substrate 91.
  • the lens structure 95aa is arranged with the same period as the period of the radiation uneven part 94a in the direction in which the radiation uneven part 94a is periodically arranged.
  • the organic EL element of this embodiment even if the light emitted from the light emitting layer included in the organic layer is captured as SPP mode light on the surface of the metal electrode, the SPP mode light is radiated unevenness on the surface of the metal electrode. It can be re-radiated as propagating light and extracted. Further, the light extracted from the surface of the metal electrode can be refracted in the front direction of the substrate by the lens structure at the interface between the substrate and the dielectric layer to increase the amount of light extracted in the front direction of the substrate.
  • FIG. 13 is a schematic cross-sectional view for explaining an example of the organic EL element according to the tenth embodiment of the present invention.
  • FIG. 13A shows a configuration in which the lens structure 105a protrudes toward the fourth dielectric layer 106 (a configuration in which the fourth dielectric layer 106 has a concave lens structure, a third dielectric layer 105 and a fourth dielectric layer). It can also be said that the lens structure is provided at the interface with 106).
  • FIG. 13B can be said to be a lens structure 106a (a configuration in which the third dielectric layer 105 has a concave lens structure, and a configuration in which a lens structure is provided at the interface between the third dielectric layer 105 and the fourth dielectric layer 106).
  • An organic EL element 110 shown in FIG. 13A includes a transparent electrode 102, an organic layer 113 including a light emitting layer, and a metal electrode 104 in this order on a substrate 101, and the opposite side of the transparent electrode 102 of the substrate 101.
  • the metal electrode 104 has a plurality of radiation uneven portions 104a periodically arranged in at least one direction on the surface 104A on the organic layer side.
  • a third dielectric layer 105 and a fourth dielectric layer 106 are provided in this order from the substrate 101 side on the opposite side of the substrate 101 from the transparent electrode 102, and the third dielectric layer 105 has a refractive index of 0.
  • the third dielectric layer 105 has a refractive index difference of 1 or less or a refractive index higher than that of the substrate 101, and the refractive index of the third dielectric layer 105 is higher than that of the fourth dielectric layer 106 (the refractive index difference is 0.2 or more).
  • the third dielectric layer 105 includes a lens structure (tenth lens structure) 105a protruding toward the fourth dielectric layer 106 at the interface with the fourth dielectric layer 106, and the lens structure 105a has a radiation unevenness. It arrange
  • the reason why the third dielectric layer 105 has a refractive index difference of 0.1 or less with respect to the substrate 101 or a refractive index higher than that of the substrate 101 is that when the light enters the third dielectric layer 105 from the substrate 101, total reflection is not caused. This is to prevent it from happening. Further, the reason that the difference in refractive index between the third dielectric layer 105 and the fourth dielectric layer 106 is 0.2 or more is to refract light at the interface and to exhibit a sufficient light collecting effect as a lens. .
  • this organic EL element is a bottom emission type organic EL element like the organic EL element of the first embodiment
  • the thickness of the material of the substrate 101 is the same as that of the substrate 1 of the first embodiment. Can be used.
  • the same material as the transparent electrode material of the first embodiment can be used.
  • the thickness of the transparent electrode 102 is not particularly limited. For example, it is 10 to 2000 nm, preferably 50 to 1000 nm. If it is thinner than 10 nm, the sheet resistance of the transparent electrode 102 increases. If it is thicker than 2000 nm, the transmittance of the transparent electrode 102 is lowered.
  • the metal electrode 104 has a plurality of radiation uneven portions 104a periodically disposed in at least one direction on the surface 104A on the organic layer side.
  • the period of at least one direction of the radiation uneven portion 104 a is the same as the period of one direction of the lens structure 105 a of the third dielectric layer 105.
  • the configuration of the radiation uneven portion 104a can be the same as that of the organic EL element of the first embodiment.
  • the metal electrode 104 may be the same material and thickness as those in the first embodiment.
  • the organic layer 103 is disposed between the transparent electrode 102 and the metal electrode 104, and has a layered portion 103 d and a convex portion 103 e having a shape complementary to the shape of the radiation uneven portion 104 a of the metal electrode 104.
  • the same material and thickness as those in the first embodiment can be used.
  • the third dielectric layer 105 is disposed on the opposite side of the substrate 101 from the transparent electrode 102 and has a refractive index difference of 0.1 or less or a refractive index higher than that of the substrate 111 and a fourth dielectric.
  • the refractive index difference with the layer 106 is 0.2 or more, and the lens structure 105 a is provided on the interface between the layered portion 105 d and the fourth dielectric layer 106 on the substrate 111 side.
  • the third dielectric layer 105 may have a structure without the layered portion 105d.
  • the third dielectric layer 105 has a refractive index similar to the refractive index of the substrate 101 (for example, a refractive index with a refractive index difference of 0.1 or less) so that total reflection does not occur at the interface with the substrate 101, or It is preferable to have a refractive index higher than that of the substrate 101.
  • the material for the third dielectric layer 105 is not particularly limited. For example, SOG satisfying the above refractive index, ZnO (typical refractive index: 2.02), or the like can be used.
  • the fourth dielectric layer 106 is disposed on the opposite side of the third dielectric layer 105 from the substrate 101 and has a concave portion 106 a having a shape complementary to the shape of the lens structure 105 a of the third dielectric layer 105.
  • the material of the fourth dielectric layer 106 is not particularly limited. For example, SOG, polyethylene naphthalate (typical refractive index: 1.77), MgO (typical refraction) satisfying the above refractive index conditions. Rate: 1.74) can be used.
  • the thickness of the fourth dielectric layer 106 needs to be greater than the height of the lens structure 105 a of the third dielectric layer 105.
  • the SPP mode light captured on the surface of the metal electrode Is re-radiated as propagating light at the radiation uneven portion 104 a on the surface of the metal electrode and extracted, passes through the organic layer 103 and the transparent electrode 102, and enters the substrate 101.
  • the light further passes through the substrate 101 and enters the layered portion 105d of the third dielectric layer 105, and reaches the interface between the lens structure 105a of the third dielectric layer 105 and the recessed portion 106c of the fourth dielectric layer 106.
  • the organic EL element shown in FIG. 13B has a configuration in which the protruding direction of the lens structure faces the opposite side with respect to the organic EL element shown in FIG.
  • the materials of the third dielectric layer 105 and the fourth dielectric layer 106 are selected so that the refractive index of the third dielectric layer 105 is lower than the refractive index of the fourth dielectric layer 106.
  • the lens action (condensing function) similar to that of the organic EL element shown in FIG. 13A can be exhibited, and the same light extraction effect as that of the organic EL element shown in FIG. 13A can be obtained.
  • the fourth dielectric layer 106 has a refractive index higher than the refractive index of the third dielectric layer 105 (refractive index difference is 0.2 or more) and the third dielectric layer 105.
  • a lens structure (tenth lens structure) 106a protruding to the substrate side is provided at the interface, and the lens structure 106a is arranged at the same period as the period of the radiation uneven part 104a in the direction in which the radiation uneven part 104a is periodically arranged.
  • a material having such a relationship between the refractive indexes of the third dielectric layer 105 and the fourth dielectric layer 106 is opposite to that of the refractive index used in the organic EL element shown in FIG. Can be obtained.
  • the organic EL element of this embodiment even if the light emitted from the light emitting layer included in the organic layer is captured as SPP mode light on the surface of the metal electrode, the SPP mode light is radiated unevenness on the surface of the metal electrode. It can be re-radiated as propagating light and extracted. Further, the light extracted from the surface of the metal electrode is refracted in the front direction of the substrate by the lens structure at the interface between the third dielectric layer 105 and the fourth dielectric layer 106, and the amount of light extracted in the front direction of the substrate Can be increased.
  • FIG. 14 is a schematic cross-sectional view for explaining an example of the organic EL element according to the eleventh embodiment of the present invention.
  • An organic EL element 120 shown in FIG. 14 includes a transparent electrode 112, an organic layer 113 including a light emitting layer, and a metal electrode 114 in this order, and a substrate 111 on the surface of the metal electrode 114 opposite to the organic layer 113.
  • the organic EL element is configured to extract light from the transparent electrode 112 side to the outside.
  • the metal electrode 114 has a plurality of radiation uneven portions 114a periodically arranged in at least one direction on the surface 114A on the organic layer side.
  • the transparent electrode 112 includes a lens structure (eleventh lens structure) 112a that protrudes outside the element.
  • the lens structure 112a is arranged with the same period as the period of the radiation uneven part 114a in the direction in which the radiation uneven part 114a is periodically arranged.
  • This organic EL element is a top emission type organic EL element, and is usually used for an opaque substrate such as a metal substrate and other top emission type organic EL elements in addition to the same as the substrate 1 of the first embodiment.
  • Substrate can be used.
  • the transparent electrode 112 is disposed on the opposite side of the organic layer 113 from the metal electrode 114 and has a refractive index difference of 0.1 or less or a refractive index higher than that of the organic layer 113 and higher than that of the organic layer 113. It has a layered portion 112b on the side and a lens structure 112a on the interface with the atmosphere.
  • the transparent electrode 112 may have a structure without the layered portion 112d.
  • the reason why the transparent electrode 112 has a refractive index difference of 0.1 or less with the organic layer 113 or a higher refractive index than the organic layer 113 is that it does not cause total reflection when light enters the transparent electrode 112 from the organic layer 113. It is.
  • the thickness of the transparent electrode 112 is not particularly limited. For example, it is 10 to 2000 nm, preferably 50 to 1000 nm. If the thickness is less than 10 nm, the sheet resistance of the transparent electrode 12 increases, and if it is more than 2000 nm, the transmittance of the transparent electrode 112 decreases.
  • the metal electrode 114 has a plurality of radiation uneven portions 114a periodically disposed in at least one direction on the surface 114A on the organic layer side.
  • the period in at least one direction of 114 a is the same as the period in one direction of the lens structure 112 a of the transparent electrode 112.
  • the configuration of the radiation uneven portion 114a can be the same as that of the organic EL element of the first embodiment.
  • the metal electrode 114 may be the same material and thickness as those in the first embodiment.
  • the organic layer 113 is disposed between the transparent electrode 112 and the metal electrode 114, and has a layered portion 113d and a convex portion 113e having a shape complementary to the shape of the radiation uneven portion 114a of the metal electrode 114.
  • the same material and thickness as those in the first embodiment can be used.
  • the SPP mode light captured on the surface of the metal electrode is reflected on the surface of the metal electrode.
  • the radiation unevenness 114a is re-radiated and propagated as propagation light, passes through the organic layer 113 and the layered portion 112d of the transparent electrode 112, and enters the lens structure 112a.
  • the light reaching the interface between the lens structure 112a 1 (112a) and the atmosphere enters the atmosphere from the transparent electrode 112 having a refractive index higher than the refractive index of the atmosphere, and the center line of the lens structure 112a 1 (112a). Refracts toward the CC side.
  • the lens structure 112a even if the light re-radiated as the propagation light by the radiation uneven portion 114a of the metal electrode 114 enters the lens structure 112a in a direction away from the center line CC of the lens structure 112a of the transparent electrode 112, the lens structure 112a. Is refracted toward the center line CC side and taken out of the element. Thereby, the extraction of light in the front direction of the substrate increases.
  • the organic EL element of this embodiment even if the light emitted from the light emitting layer included in the organic layer is captured as SPP mode light on the surface of the metal electrode, the SPP mode light is radiated unevenness on the surface of the metal electrode. It can be re-radiated as propagating light and extracted. Further, the light extracted from the surface of the metal electrode can be refracted in the front direction of the substrate by the lens structure at the interface between the transparent electrode 112 and the atmosphere, and the amount of light extracted in the front direction of the substrate can be increased.
  • FIG. 15 is a cross-sectional schematic diagram for demonstrating an example of the organic EL element which concerns on the 12th Embodiment of this invention.
  • An organic EL element 130 shown in FIG. 15 includes a transparent electrode 122, an organic layer 123 including a light emitting layer, and a metal electrode 124 in this order, and a substrate 121 on the surface of the metal electrode 124 opposite to the organic layer 123.
  • the organic EL element is configured to extract light from the transparent electrode 122 side to the outside.
  • the metal electrode 124 has a plurality of radiation uneven portions 124a periodically arranged in at least one direction on the surface 124A on the organic layer side.
  • the transparent electrode 122 has a dielectric layer 125 on the opposite side of the substrate 121, and the dielectric layer 125 has a refractive index difference of 0.1 or less from the refractive index of the transparent electrode 122 or the refractive index of the transparent electrode 122. Has a high refractive index.
  • the dielectric layer 125 is provided with a lens structure (a twelfth lens structure) 125a projecting out of the element on the surface opposite to the transparent electrode 122.
  • the lens structure 125a is periodically arranged with radiation uneven portions 124a. It arrange
  • the reason why the dielectric layer 125 has a refractive index difference of 0.1 or less with respect to the transparent electrode 122 or a higher refractive index than the transparent electrode 122 is that when the light enters the dielectric layer 125 from the transparent electrode 122, total reflection occurs. This is to prevent it from happening.
  • This organic EL element is a top emission type organic EL element, and is usually used for an opaque substrate such as a metal substrate and other top emission type organic EL elements in addition to the same as the substrate 1 of the first embodiment.
  • Substrate can be used.
  • the same material as the transparent electrode material of the first embodiment can be used.
  • the thickness of the transparent electrode 122 is not particularly limited. For example, it is 10 to 2000 nm, preferably 50 to 1000 nm. If the thickness is less than 10 nm, the sheet resistance of the transparent electrode 12 increases, and if it is more than 2000 nm, the transmittance of the transparent electrode 112 decreases.
  • the metal electrode 124 has a plurality of radiation uneven portions 124a periodically arranged in at least one direction on the surface 124A on the organic layer side.
  • a period in at least one direction of the radiation uneven portion 124 a is the same as a period in one direction of the lens structure 125 a of the dielectric layer 125.
  • the configuration of the radiation uneven portion 124a can be the same as that of the organic EL element of the first embodiment.
  • the metal electrode 124 may be the same material and thickness as those in the first embodiment.
  • the organic layer 123 is disposed between the transparent electrode 122 and the metal electrode 124, and has a layered portion 123 d and a convex portion 123 e having a shape complementary to the shape of the radiation uneven portion 124 a of the metal electrode 124.
  • the same material and thickness as those in the first embodiment can be used.
  • the dielectric layer 125 is disposed on the opposite side of the transparent electrode 122 from the substrate 121 and has a refractive index difference of 0.1 or less or a refractive index higher than that of the transparent electrode 122 and the transparent electrode 122. It has a layered portion 125d on the side and a lens structure 125a at the interface with the atmosphere.
  • the dielectric layer 125 may have a structure without the layered portion 125b.
  • the material of the dielectric layer 125 the same materials as those mentioned for the first dielectric layer 45 of the fourth embodiment can be used, but it is necessary to satisfy the above-mentioned refractive index condition. .
  • the SPP mode light captured on the surface of the metal electrode is reflected on the surface of the metal electrode.
  • the radiation unevenness 124 a is re-radiated as propagating light and extracted, passes through the organic layer 123 and the transparent electrode 122, and enters the dielectric layer 125.
  • the lens structure 125a 1 (125a) enters the lens structure 125a 1 (125a) through the layer portion 125d of the dielectric layer 125, the light reaching the interface between the lens structure 125a 1 and (125a) and the atmosphere, a higher refractive index than the refractive index of the atmosphere Refracts toward the center line CC side of the lens structure 125a 1 (125a) at the interface entering the atmosphere from the dielectric layer 125 having Thus, even if the light re-radiated as the propagation light by the radiation uneven portion 124a of the metal electrode 124 enters the lens structure 122a in a direction away from the center line CC of the lens structure 122a of the transparent electrode 122, the lens structure 122a. Is refracted toward the center line CC side and taken out of the element. Thereby, the extraction of light in the front direction of the substrate increases.
  • the organic EL element of this embodiment even if the light emitted from the light emitting layer included in the organic layer is captured as SPP mode light on the surface of the metal electrode, the SPP mode light is radiated unevenness on the surface of the metal electrode. It can be re-radiated as propagating light and extracted. Further, the light extracted from the surface of the metal electrode can be refracted in the front direction of the substrate by the lens structure at the interface between the dielectric layer 125 and the atmosphere to increase the amount of light extracted in the front direction of the substrate.
  • corrugation part of the metal electrode of the organic EL element of this invention can take a various structure. It is preferable that the center of gravity of each unit structure of the radiation uneven portion coincides with the center of the lens structure in plan view (as viewed from the normal direction of the metal electrode surface).
  • FIG. 16 is a schematic diagram of a cross-section along the normal direction of the metal electrode surface, illustrating a convex radiation uneven portion.
  • (A) is a shape having an inverse taper
  • (b) is a semicircular shape
  • (c) is a circular shape
  • (d) is a shape having a vertical taper
  • (e) is a forward shape.
  • a shape having a taper (f-1) is a triangular shape (an example having a hypotenuse symmetrical to the normal of the metal electrode surface), and (f-2) is a triangular shape (the metal electrode surface (Example of a case having a hypotenuse asymmetric with respect to the normal), (g) is a shape having a sharp point, (h) is a configuration having a plurality of rectangular convex portions (double convex portion), This is a case where the asymmetric convex shape of f-2) is alternately arranged in the opposite direction to form the entire radiation uneven portion.
  • FIG. 16 exemplifies a concave radiation uneven portion having the same shape as the convex shape shown in FIG. 16, and is a schematic diagram of a cross section along the normal direction of the metal electrode surface.
  • (I) is a shape having an inverse taper
  • (j) is a semicircular shape
  • (k) is a circular shape
  • (l) is a shape having a vertical taper
  • (m) is a forward taper.
  • (N-1) is a triangular shape (an example having a hypotenuse symmetrical to the normal line of the metal electrode surface)
  • (n-2) is a triangular shape (the metal electrode surface method)
  • (o) is a shape having a sharp point
  • (p) is a configuration having a plurality of rectangular recesses (multiple recesses)
  • (n-2 ′) is (n ⁇ 2 ′) )
  • (N-2) may have a configuration in which the radiation uneven portions are entirely arranged by combining those having different directions, and (n-2 ′) is an example.
  • one radiant uneven portion has one convex or concave shape, but one radiant uneven portion has a plurality of convex and / or concave shapes. It may consist of In (f-2 ′) and (n-2 ′), one radiating concavo-convex part has one convex shape or concave shape.
  • An SPP that propagates through the interface between the metal electrode and the organic layer when the surface on the organic layer side of the metal electrode has the convex shape or concave shape shown in (a) to (p), and the convex shape and / or concave shape that is a combination thereof.
  • the mode light is re-radiated by these uneven shapes, and converted into propagating light that radiates into the organic layer around each uneven shape. That is, each of these concavo-convex structures acts as a radiation starting point for SPP mode light.
  • FIG. 18 shows another example of the convex radiating concavo-convex portion, and is a schematic diagram of a cross section along the normal direction of the metal electrode surface.
  • the convex shape is a case where (q) is a bowl shape, (r) a rectangular wave shape, and (s) is a single sawtooth shape.
  • the dimensions described in each structure in FIG. 18 are examples and do not specify the invention, and are dimensions used in a model used in the later-described embodiment (simulation) (units of dimensions in the figure). Is nm).
  • FIG. 19 illustrates a concave radiation uneven portion having the same shape as the convex shape shown in FIG. 18, and is a schematic diagram of a cross section along the normal direction of the metal electrode surface.
  • the concave shape is a case where (t) is a bowl-like shape, (u) a rectangular wave shape, and (v) is a single sawtooth wave shape. If the surface of the metal electrode on the organic layer side has a concavo-convex shape such as (q) to (v), the SPP mode light propagating through the interface between the metal electrode and the organic layer may be a boundary between adjacent structures or a rugged switching portion. And is converted into propagating light that radiates into the organic layer around these uneven shapes. That is, this part acts as a radiation starting point for the SPP mode light.
  • FIG. 20 is a diagram illustrating an example of an image display device including the organic EL element.
  • An image display device 200 shown in FIG. 20 is a so-called passive matrix type image display device.
  • a transparent electrode wiring 204, a transparent electrode auxiliary wiring 206, a metal electrode wiring 208, an insulating film 210, A metal electrode partition wall 212, a sealing plate 216, and a sealing material 218 are provided.
  • a plurality of transparent electrode wirings 204 are formed on the substrate 1 of the organic EL element 10.
  • the transparent electrode wirings 204 are arranged in parallel at a constant interval.
  • the transparent electrode wiring 204 is made of a transparent conductive film, and for example, ITO (Indium Tin Oxide) can be used.
  • the thickness of the transparent electrode wiring 204 can be set to 100 nm to 150 nm, for example.
  • a transparent electrode auxiliary wiring 206 is formed on the end portion of each transparent electrode wiring 204.
  • the transparent electrode auxiliary wiring 206 is electrically connected to the transparent electrode wiring 204.
  • the transparent electrode auxiliary wiring 206 functions as a terminal for connecting to the external wiring on the end side of the substrate 1, and the transparent electrode auxiliary wiring 206 is connected from a drive circuit (not shown) provided outside. A current can be supplied to the transparent electrode wiring 204 through the wiring.
  • the transparent electrode auxiliary wiring 206 is made of a metal film having a thickness of 500 nm to 600 nm, for example.
  • a plurality of metal electrode wirings 208 are provided on the organic EL element 10.
  • the plurality of metal electrode wirings 208 are arranged so as to be parallel to each other and orthogonal to the transparent electrode wiring 204.
  • Al or an Al alloy can be used for the metal electrode wiring 208.
  • the thickness of the metal electrode wiring 208 is, for example, 100 nm to 150 nm.
  • a metal electrode auxiliary wiring (not shown) is provided at the end of the metal electrode wiring 208 and is electrically connected to the metal electrode wiring 208. Therefore, a current can flow between the metal electrode wiring 208 and the metal electrode auxiliary wiring.
  • an insulating film 210 is formed on the substrate 1 so as to cover the transparent electrode wiring 204.
  • the insulating film 210 is provided with a rectangular opening 220 so that a part of the transparent electrode wiring 204 is exposed.
  • the plurality of openings 220 are arranged in a matrix on the transparent electrode wiring 204.
  • the organic EL element 10 is provided between the transparent electrode wiring 204 and the metal electrode wiring 208. That is, each opening 220 is a pixel. Accordingly, a display area is formed corresponding to the opening 220.
  • the film thickness of the insulating film 210 can be, for example, 200 nm to 1000 nm, and the size of the opening 220 can be, for example, 100 ⁇ m ⁇ 100 ⁇ m.
  • the organic EL element 10 is located between the transparent electrode wiring 204 and the metal electrode wiring 208 in the opening 220.
  • the transparent electrode 2 of the organic EL element 10 is in contact with the transparent electrode wiring 204
  • the metal electrode 4 is in contact with the metal electrode wiring 208.
  • the thickness of the organic EL element 10 can be set to, for example, 150 nm to 200 nm.
  • a plurality of metal electrode partition walls 212 are formed on the insulating film 210 along a direction orthogonal to the transparent electrode wiring 204 in plan view.
  • the metal electrode partition wall 212 plays a role for spatially separating the plurality of metal electrode wirings 208 so that the wirings of the metal electrode wirings 208 do not conduct with each other. Therefore, the metal electrode wiring 208 is disposed between the adjacent metal electrode partition walls 212.
  • the size of the metal electrode partition wall 212 for example, one having a height of 2 to 3 ⁇ m and a width of 10 ⁇ m can be used.
  • the substrate 1 is bonded to each other through a sealing plate 216 and a sealing material 218.
  • the space in which the organic EL element 10 is provided can be sealed, and the organic EL element 10 can be prevented from being deteriorated by moisture in the atmosphere.
  • the sealing plate 216 for example, a material having a thickness of 0.7 mm to 1.1 mm can be used.
  • the sealing plate 216 may not be transparent when light is extracted from the substrate 1 side as in the case of a bottom emission type element.
  • the sealing plate 216 needs to be transparent with respect to at least a part of the emission wavelength region.
  • a current is supplied to the organic EL element 10 through a transparent electrode auxiliary wiring 106 and a metal electrode auxiliary wiring (not shown) by a driving device (not shown) to cause the light emitting layer to emit light. it can. Then, light can be emitted from the substrate 1 through the substrate 1.
  • the image display device 200 can display an image 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. 21 is a diagram illustrating an example of a lighting device including the organic EL element 10 described above.
  • the lighting device 300 shown in FIG. 21 includes the organic EL element 10 described above and a terminal 302 that is installed adjacent to the substrate 1 (see FIG. 1) of the organic EL element 10 and connected to the transparent electrode 2 (see FIG. 1). And a terminal 303 connected to the metal electrode 4 (see FIG. 1), and a lighting circuit 301 for driving the organic EL element 10 connected to the terminal 302 and the terminal 303.
  • the lighting circuit 301 has a DC power source (not shown) and a control circuit (not shown) inside, and supplies a current between the transparent electrode layer 2 and the metal electrode 4 of the organic EL element 10 through the terminal 302 and the terminal 303. 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 substrate of the organic EL element of the present invention, the transparent electrode, the dielectric layer (all dielectric layers described in the present specification), and the hemispherical convex portions and concave portions provided in the organic layer are formed by known photolithography pattern formation. It can be formed using technology. In particular, by adjusting the etching selection ratio (etching rate of the material to be etched / etching rate of the mask) to a low level, the etching proceeds while the mask is being etched, so that a curved surface shape is formed.
  • the etching selection ratio etching rate of the material to be etched / etching rate of the mask
  • the resin sheet which has a hemispherical recessed part or a convex part can be manufactured by resin-molding using the metal mold
  • a metal electrode is formed on a substrate. It can be formed by a conventional method such as resistance heating vapor deposition, electron beam vapor deposition, sputtering, ion plating, or CVD.
  • irregularities are formed by laser patterning, dry etching, and wet etching. For example, a structure with a perpendicular taper as shown in FIGS.
  • 16D, 16H, 17L, and 17P may use a resist mask with high etching resistance and etching with high anisotropy.
  • the forward taper structure has a taper shape suitable as a mask and a comparison of etching resistance. It can be formed by using a low resist.
  • a shape including a reverse taper as shown in FIGS. 16A, 16C, 17I, and 17K can be formed by the following method, for example.
  • a sacrificial layer is formed on a metal electrode by using, for example, a plasma CVD method using a material having a significantly different etching rate from that of the metal electrode layer, such as phosphosilicate glass (PSG).
  • a predetermined portion of the sacrificial layer is etched to leave a portion that is to have a reverse taper shape and a portion that is in a positive / negative relationship (that is, a forward taper shape).
  • the metal electrode layer is formed by the above-described method so that the space between the sacrificial layers is sufficiently filled.
  • the electrode layer is removed by chemical mechanical polishing (CMP) or an etch back process so that the surface of the sacrificial layer is exposed.
  • CMP chemical mechanical polishing
  • the sacrificial layer is removed by general dry etching or wet etching, and an uneven structure having an inversely tapered shape is formed on the metal electrode.
  • An organic layer, a transparent electrode (ITO, etc.), a dielectric layer, and a substrate (SOG or polymer) are formed in this order.
  • the lens structure is formed on the upper surface of the organic layer, the upper surface of the transparent electrode, the upper surface of the dielectric layer, or the surface of the substrate by the above photolithography.
  • the substrate 1 may be removed in the final process or other processes.
  • Method of manufacturing from the transparent electrode side in the case of the configuration of [substrate 1 / transparent electrode / organic layer / metal electrode]) (1)
  • the lens structure for example, a recess
  • a transparent electrode is formed using ion plating or the like.
  • the concave portion When the substrate has a lens structure (concave portion), the concave portion is filled. (3) When the transparent electrode has a lens structure (for example, a recess), the lens structure is formed on the upper surface of the transparent electrode by the photolithography described above. (4) An organic layer is formed, and an uneven structure is formed on the upper surface by photolithography. (5) A metal electrode is vapor-deposited, and a metal electrode having a radiation uneven portion is formed by following the uneven structure.
  • FIGS. 22A and 22B show the fifth example shown in FIG. 8A as an example in order to show the effect of the combination of the radiation uneven portion and the lens structure, which is a feature of the organic EL element of the present invention.
  • the embodiment shows a result of computer simulation calculation of light extraction efficiency using a finite difference time domain method (FDTD).
  • FDTD finite difference time domain method
  • Maxwell's equation describing the time change of the electromagnetic field is differentiated spatially and temporally, and the time change of the electromagnetic field at each point in the space is tracked. More specifically, the light emission in the light emitting layer is regarded as radiation from a minute dipole, and the time change of the radiation (electromagnetic field) is traced.
  • the simulation result shows the result of light extraction to the substrate.
  • ⁇ on the horizontal axis is the wavelength
  • ⁇ on the vertical axis is the light extraction efficiency (absolute value).
  • the calculation was performed when the direction of the minute dipole was the X direction and the Y direction (direction parallel to the substrate surface) and the Z direction (direction perpendicular to the substrate surface).
  • the light emitted from the dipoles in the X and Y directions is mainly light propagating in the direction perpendicular to the substrate surface
  • the light emitted from the dipoles in the Z direction is light propagated in a direction parallel to the substrate surface. Is the main.
  • the light emitted from the dipoles in the X and Y directions may be referred to as vertical propagation light
  • the light emitted from the Z direction dipole may be referred to as parallel propagation light
  • FIGS. 22A and 22B show the light extraction efficiency of vertically propagating light and the light extraction efficiency of parallel propagating light, respectively.
  • the vertical axis represents the light extraction efficiency ⁇
  • the horizontal axis represents the radiation wavelength ⁇ .
  • “In light emission” and “out light emission” respectively indicate a case where light is emitted directly under the radiation uneven portion and a case where light is emitted between adjacent radiation uneven portions as shown in FIG.
  • the position of the dipole in the film thickness direction is the center of the film thickness of the organic layer.
  • FIG. 23 is a cross-sectional view showing a model structure of the organic EL element of the fifth embodiment used in the simulation calculation.
  • the refractive index values used for the calculation are as follows.
  • the substrate 61 is made of glass, and a refractive index of 1.5 is used.
  • the transparent electrode 62 is made of ITO, the refractive index is 1.82 + 0.009i at 550 nm, and other wavelengths are extrapolated by the Lorentz model.
  • the dielectric layer 55 provided between the substrate and the transparent electrode has a refractive index of 1.9. Further, 1.72 was used as the refractive index of the organic layer 53.
  • the metal electrode 54 is made of aluminum (Al)
  • the refractive index is 0.958 + 6.69i at 550 nm, and other wavelengths are extrapolated by the Drude model.
  • the thicknesses of the transparent electrode 52, the organic layer 53, and the metal electrode 54 were 150 nm, 100 nm, and 150 nm, respectively.
  • the radiation uneven portion 54a is a rectangular concave shape, the width is 100 nm, the depth is 50 nm, and the arrangement period of the radiation uneven portion 54a is 500 nm.
  • the lens structure 55a made of the dielectric layer 55 is hemispherical, and its diameter (corresponding to w in FIG.
  • the lens structures 55a are arranged adjacent to each other, and have a structure without the layered portion of the dielectric layer shown in FIG.
  • the present invention improves the light extraction efficiency by effectively extracting SPP mode light and waveguide mode light by combining the radiation uneven portion and the lens structure, but the effect of the combination of this radiation uneven portion and the lens structure 24 (a) and 24 (b) show the light extraction efficiencies of the vertical direction propagation light and the parallel direction propagation light, respectively, as a result of the simulation with only the radiation uneven portion. That is, as the model structure of the organic EL element used in the simulation calculation in the case of only the radiation uneven part, a model structure without a lens-like dielectric layer between the substrate and the transparent electrode in FIG. 23 was used. The thicknesses of the transparent electrode 52, the organic layer 53, and the metal electrode 54 were the same as the model shown in FIG. The simulation result is a result of “out light emission”.
  • the structure of only the radiation uneven portion is a solid structure (not transparent on the substrate glass made of ITO) having no radiation uneven portion and a lens structure.
  • the light extraction of vertically propagating light is higher than the standard structure (solid structure) in both cases of “in light emission” and “out light emission”. Shows efficiency. This indicates that, unlike the structure of only the radiation uneven portion, the structure in which the radiation uneven portion and the lens structure are combined has an effect of improving the light extraction of the vertically propagating light.
  • the light extraction efficiency is significantly higher than that of the standard structure (solid structure). Show. In particular, “out emission” shows higher light extraction efficiency. As described above, it has been found that the structure in which the radiation uneven portion of the present invention and the lens structure are combined can effectively extract SPP mode light and waveguide mode light and improve light extraction efficiency.
  • the arrangement period of the radiation irregularities is set to 1000 nm, and the diameter and arrangement period (distance between adjacent lens structures) of the lens structure made of the high dielectric layer are both.
  • the result of having performed simulation about the same structure as FIG. 23 except having set it as 1000 nm is shown.
  • “standard” in the legend indicates the standard structure.
  • the arrangement period of the radiation irregularities is 1000 nm, the diameter of the lens structure, and the arrangement period of 1000 nm, both in “in light emission” and “out light emission” than in the standard structure (solid structure). It shows high light extraction efficiency.
  • the structure in which the radiation uneven portion and the lens structure are combined has an effect of improving the light extraction of the vertically propagating light.
  • the light extraction of the parallel propagation light is significantly higher than the standard structure (solid structure) in both “in light emission” and “out light emission”. Shows efficiency. In particular, “out emission” shows higher light extraction efficiency.
  • FIGS. 26A and 26B are the same as FIGS. 23A and 23B except that the arrangement period of the radiation uneven portion and the diameter and arrangement period of the lens structure are all 300 nm, 500 nm, 800 nm, and 1200 nm.
  • the result of having performed simulation about the same structure is shown.
  • the simulation result is a result of “in light emission”.
  • “standard” in the legend indicates the standard structure.
  • FIGS. 27 (a) and 27 (b) show the same structure as FIG. 26 except that the arrangement period of the radiation irregularities and the diameter and arrangement period of the lens structure are 1600 nm, 2200 nm, and 3000 nm, respectively. Shows the result of simulation.
  • the simulation result is a result of “in light emission”.
  • “standard” in the legend indicates the standard structure.
  • both the vertical direction propagation light and the parallel direction propagation light show higher light extraction efficiency than the standard structure (solid structure).
  • the light extraction efficiency is dramatically higher than that of the standard structure (solid structure).
  • Such an improvement in the high light extraction efficiency is due to a structure in which the radiation uneven portion and the lens structure are combined.
  • it hardly depends on the diameter of the lens structure (hemispherical lens). This is difficult to predict even for those skilled in the art, and is a knowledge that can be obtained only after simulation.
  • 28 (a) and 28 (b) respectively show the same structure as FIG. 26 except that the arrangement period of the concave radiation irregularities, the diameter and arrangement period of the lens structure made of the dielectric layer are both 500 nm and 1000 nm.
  • vertical dipole of an "out light emission" position by the FDTD method is shown.
  • the wavelength of the emitted light was 620 nm.
  • the upper side is the substrate, and the lower side is the metal electrode.
  • the propagation light in the parallel direction rises in the vertical direction as a whole. It can also be seen that the propagation of the SPP mode light is converted into radiated light at the concave radiant uneven portion.
  • the difference between the radiation patterns in FIGS. 28A and 28B is considered to be due to the interference between the radiation from the dipole and the re-radiated light of the SPP mode light from the radiation uneven portion.
  • the light extraction effect can be optimized by adjusting the distance between the uneven portions.
  • FIG. 29 is a plan view for explaining an example of the combination of the radiation uneven portion and the lens structure shown in FIGS.
  • the line-shaped radiation irregularities having the cross-sections shown in FIGS. 16 to 19 and periodically arranged in parallel and the lens structure arranged in a square lattice form include each line of the radiation irregularities and the lens.
  • This is a combination in which the columns of the structure are arranged so that the center lines in the width direction thereof coincide.
  • Symbols A and B in FIG. 29 respectively indicate a part of the plurality of lines of the radiation uneven portion and a part of the plurality of lens structures.
  • each line of the radiation uneven portion and the column of the lens structure is not limited to this combination, and may be a configuration in which the line of the radiation uneven portion and the column of the lens structure are arranged in a mesh shape.
  • FIG. 30 shows a computer simulation calculation of the light extraction efficiency using the FDTD method for the combination of the convex radiant projections and lens structures shown in FIGS. 16A to 16C, FIG. The results are shown.
  • the “reverse taper”, “semicircle”, “circle”, “double convex portion”, and “vertical taper” in the legend are sequentially shown in FIGS.
  • corrugated part shown by each of these and a lens structure is shown.
  • “standard” in the legend indicates the above-mentioned standard structure.
  • 30 (a) to 30 (c) show the light extraction efficiency of the radiated light from the dipoles in the x, y, and z directions in FIG. 29, respectively.
  • the light emitted from the dipole in the x direction and the dipole in the y direction is vertically propagating light
  • the light emitted from the dipole in the z direction is parallel propagating light.
  • FIG. 31 is a cross-sectional view showing a model structure of the organic EL element of the fifth embodiment used in the simulation calculation.
  • the model structure a structure in which the concave portion of the radiation uneven portion coincides with the center of the lens structure was used.
  • the refractive index values used for the calculation are as follows.
  • the substrate 61 is made of glass, and a refractive index of 1.52 is used.
  • the transparent electrode 52 is made of ITO, the refractive index is 1.82 + 0.009i at 550 nm, and other wavelengths are extrapolated by the Lorentz model.
  • the dielectric layer 55 provided between the substrate and the transparent electrode has a refractive index of 1.90.
  • the refractive index of the organic layer 53 was 1.72.
  • the metal electrode 54 is made of aluminum (Al)
  • the refractive index is 0.649 + 4.32i at 550 nm, and other wavelengths are extrapolated by the Drude model.
  • the thicknesses of the transparent electrode 52, the organic layer 53, and the metal electrode 54 were 150 nm, 130 nm, and 150 nm, respectively.
  • the radiation uneven portion 54a has the shape and size shown in FIG.
  • the lens structure 55a composed of the dielectric layer 55 was also 1 ⁇ m.
  • the lens structure is a structure that is continuously connected in a square lattice shape, and the width of the lens structure 55a (corresponding to w in FIG. 1) is set to 1 ⁇ m, which is equal to the arrangement period of the lens structure 55a.
  • the simulation calculation shown below was also performed with the same model structure.
  • the light extraction efficiency from the dipole in any of the x, y, and z directions is higher than that of the standard structure in the entire range of 450 nm to 750 nm.
  • the light extraction efficiency of the radiated light from the dipole in the z direction is significantly higher than that of the standard structure.
  • the structure in which the radiation uneven portion of the present invention and the lens structure are combined can effectively extract SPP mode light and waveguide mode light and improve light extraction efficiency.
  • the radiated light from the dipole of the x direction dipole has a larger shape dependency of the metal electrode uneven portion than the radiated light from the dipole in the y direction.
  • the light extraction efficiency is generally “vertical taper”, “semicircle”, “circle,“ double line ”,“ reverse ”in the range of 450 nm to 650 nm. In the range of 650 nm to 750 nm, it was found that “double line”, “reverse taper”, “circle”, “vertical taper”, and “semicircle” were higher in the range of 650 nm to 750 nm.
  • FIG. 32 shows the result of computer simulation calculation of the light extraction efficiency using the FDTD method for the combination of the convex radiation uneven portion and the lens structure shown in FIGS. 16 (e) to (g).
  • the “forward taper”, “triangle (symmetric)”, “pointer”, and “triangle (asymmetric)” in the legend are in order of FIG. 16 (e), (f-1), (g), (f-2 ′). It shows that it is a result of the combination of the convex radiation
  • “standard” in the legend indicates the standard structure.
  • the model structure of “triangular (asymmetric)” is a structure in which the center of gravity of the asymmetric convex shape of (f-2) coincides with the center of the lens structure, and the distance between the centers of adjacent convex shapes, The distance between the centers of adjacent lens structures is 1 ⁇ m.
  • FIGS. 32A to 32C show the light extraction efficiency of the radiated light from the dipoles in the x, y, and z directions in FIG. 29, respectively.
  • the light extraction efficiency from the dipole in any of the x, y, and z directions is higher than that of the standard structure in the entire range of 450 nm to 750 nm.
  • the light extraction efficiency of the radiated light from the dipole in the z direction is significantly higher than that of the standard structure.
  • the structure in which the radiation uneven portion of the present invention and the lens structure are combined can effectively extract SPP mode light and waveguide mode light and improve light extraction efficiency.
  • the radiated light from the dipole of the x direction dipole has a larger shape dependency of the metal electrode uneven portion than the radiated light from the dipole in the y direction.
  • the light extraction efficiency is generally “triangular (symmetric)”, “forward tapered”, “pointed”, “triangular (asymmetric) in the range of 450 nm to 630 nm. ) ”In the order of“ triangle (asymmetric) ”,“ triangle (symmetric) ”,“ pointing ”,“ forward taper ”in the order of 650 nm to 680 nm, and“ triangle (symmetric) ”in the range of 690 nm to 750 nm. , "Forward taper", “pointer”, “triangular (asymmetric)” in order.
  • FIG. 33 shows the result of computer simulation calculation of the light extraction efficiency using the FDTD method for the combination of the concave radiation uneven portion shown in FIGS. 17 (i) to (l) and (p) and the lens structure.
  • the “reverse taper”, “semicircle”, “circle”, “double recess”, and “vertical taper” in the legend are sequentially shown in FIGS. It shows that it is the result of the combination of the convex radiation
  • the dimensions of the recesses shown in FIGS. 17 (i) to 17 (l) and (p) are the same as the dimensions of the corresponding protrusions in FIG.
  • “standard” in the legend indicates the standard structure.
  • 33 (a) to 33 (c) show the light extraction efficiency of the radiated light from the dipoles in the x, y, and z directions in FIG.
  • the light extraction efficiency from the dipole in any of the x, y, and z directions is higher than that of the standard structure in the entire range of 450 nm to 750 nm.
  • the light extraction efficiency of the radiated light from the dipole in the z direction is significantly higher than that of the standard structure.
  • the structure in which the radiation uneven portion of the present invention and the lens structure are combined can effectively extract SPP mode light and waveguide mode light and improve light extraction efficiency.
  • the radiated light from the dipole of the x direction dipole has a larger shape dependency of the metal electrode uneven portion than the radiated light from the dipole in the y direction.
  • the light extraction efficiency is “double concave part”, “vertical taper”, “semicircle”, “circle”, “ It was found that the reverse taper was higher in the order.
  • FIG. 34 shows the result of computer simulation calculation of the light extraction efficiency using the FDTD method for the combination of the concave radiation uneven portion and the lens structure shown in FIGS. 17 (m) to (o).
  • the “forward taper”, “triangle (symmetric)”, “pointer”, and “triangle (asymmetric)” in the legend are in order of FIG. 17 (m), (n ⁇ 1), (o), (n-2 ′). It shows that it is a result of the combination of the convex radiation
  • “standard” in the legend indicates the standard structure.
  • the model structure of “triangular (asymmetric)” is a structure in which the center of gravity of the asymmetric concave shape of (n ⁇ 2) coincides with the center of the lens structure, and the distance between the centers of gravity of adjacent concave shapes, and The distance between the centers of adjacent lens structures is 1 ⁇ m.
  • 34 (a) to 34 (c) show the light extraction efficiencies of radiated light from the dipoles in the x, y, and z directions in FIG. 29, respectively.
  • the light emitted from the dipole in the x direction and the dipole in the y direction is vertically propagating light, and the light emitted from the dipole in the z direction is parallel propagating light.
  • the light extraction efficiency from the dipole in any of the x, y, and z directions is higher than that of the standard structure in almost the entire range of 450 nm to 750 nm.
  • the light extraction efficiency of the radiated light from the dipole in the z direction is significantly higher than that of the standard structure.
  • the structure in which the radiation uneven portion of the present invention and the lens structure are combined can effectively extract SPP mode light and waveguide mode light and improve light extraction efficiency.
  • the radiated light from the dipole of the x direction dipole has a larger shape dependency of the metal electrode uneven portion than the radiated light from the dipole in the y direction.
  • the x dipole excites the SPP mainly propagating in the x-axis direction
  • the y dipole excites the SPP mainly propagating in the y direction.
  • all the concave portions of the metal electrode are in a line shape parallel to the y-axis, but the SPP propagating in the x direction crosses this line, so that it is more affected by the unevenness. Conceivable.
  • the light extraction efficiency is generally “forward tapered”, “triangular (symmetric)”, “pointed”, “triangular (asymmetric) in the range of 450 nm to 580 nm. ) ”In order, and in the range of 590 nm to 750 nm, it was found that“ triangle (symmetric) ”,“ forward taper ”,“ tip ”, and“ triangle (asymmetric) ”were higher in this order.
  • FIG. 35 shows the light extraction using the FDTD method for the combination of the concave radiating rugged portion and the lens structure shown in FIG. 19 (t), FIG. The result of computer simulation calculation of efficiency is shown.
  • As the model structure a structure in which the concave portion of the radiation uneven portion coincides with the center of the lens structure is used.
  • 19 (t), FIG. 19 (u), FIG. 19 (v), FIG. 18 (q) shows the result of the combination of the convex radiating concavo-convex portion and the lens structure shown in each.
  • the dimensions of the recesses shown in FIG. 19 (t), FIG. 19 (u), and FIG. 19 (v) were the same as the dimensions of the corresponding protrusions in FIG. In FIGS.
  • FIGS. 35A to 35C show the light extraction efficiency of the radiation light from the dipoles in the x, y, and z directions in FIG. 29, respectively.
  • the light emitted from the dipole in the x direction and the dipole in the y direction is vertically propagating light, and the light emitted from the dipole in the z direction is parallel propagating light.
  • the light extraction efficiency from the dipole in the x direction is higher than that of the standard structure in the range of 450 nm to 580 nm.
  • the light extraction efficiency from the dipole in the y direction is higher than the standard structure in the range of 450 nm to 650 nm.
  • the light extraction efficiency of the radiated light from the dipole in the z direction is significantly higher than that of the standard structure.
  • the light extraction efficiency is “rectangular blade shape,“ single-saw blade shape ”,“ transparent electrode orientation ”in the entire range of 450 nm to 750 nm. It was found that the shape was higher in the order of “shape” and “saddle shape for metal electrode”.
  • FIG. 36 is a plan view for explaining another example of the combination of the radiation uneven portion and the lens structure.
  • a dot-shaped radiation uneven portion having a concave cross section shown in FIG. 17L and periodically arranged, and a lens structure, each dot of the radiation uneven portion is disposed at the center of the lens structure.
  • Each of the combinations (a) and (b) is a combination arranged in a hexagonal lattice shape in plan view and a combination arranged in a tetragonal lattice shape in plan view.
  • Symbols A and B in FIG. 36 indicate a part of the dot-shaped radiation uneven portion and a part of the lens structure, respectively.
  • FIG. 37 shows the light extraction efficiency by using the FDTD method for the combination shown in FIGS. 36 (a) and (b) of the radiation uneven portion having the concave cross section shown in FIG. 17 (l) and the lens structure.
  • the result of computer simulation calculation is shown.
  • “standard” in the legend indicates the standard structure.
  • FIGS. 37A to 37C show the light extraction efficiency of the radiated light from the dipoles in the x, y, and z directions in FIG. The light emitted from the dipole in the x direction and the dipole in the y direction is vertically propagating light, and the light emitted from the dipole in the z direction is parallel propagating light.
  • the light extraction from the dipole in the x direction is higher than that of the standard structure in the range of 450 nm to 620 nm in any combination arranged in a hexagonal lattice shape and a square lattice shape in plan view. Shows efficiency. In particular, the light extraction efficiency is significantly higher than that of the standard structure in the range of 450 nm to 580 nm. Also, from FIG. 37B, the light extraction efficiency from the dipole in the y direction also shows higher light extraction efficiency than the standard structure in the range of 450 nm to 650 nm. In particular, the light extraction efficiency is significantly higher than that of the standard structure in the range of 450 nm to 620 nm. Also, from FIG.
  • the light extraction efficiency from the dipole in the z direction is higher than that of the standard structure in almost the entire range of 450 nm to 750 nm.
  • the structure in which the radiation uneven portion of the present invention and the lens structure are combined can effectively extract SPP mode light and waveguide mode light and improve light extraction efficiency.

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Abstract

La présente invention concerne un élément électroluminescent organique doté d'une électrode transparente, d'une couche organique contenant une couche émettant de la lumière et d'une électrode métallique, placés sur un substrat dans l'ordre précédemment mentionné. L'élément électroluminescent organique de la présente invention est caractérisé en ce que : l'électrode métallique est dotée d'une pluralité de projections/creux de rayonnement disposés périodiquement dans au moins une direction de la surface sur le côté couche organique ; l'électrode transparente offre un indice de réfraction supérieur à l'indice de réfraction du substrat, et elle est dotée de structures de lentilles qui font saillie en direction du substrat au niveau de l'interface avec le substrat ; et les structures de lentilles sont disposées à des intervalles identiques à ceux des projections/creux de rayonnement et dans la même direction de disposition périodique que celle des projections/creux de rayonnement.
PCT/JP2013/079535 2012-10-31 2013-10-31 Élément électroluminescent organique et dispositif d'affichage d'image et dispositif d'éclairage équipés dudit élément WO2014069565A1 (fr)

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