WO2014083693A1 - Dispositif électroluminescent - Google Patents

Dispositif électroluminescent Download PDF

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Publication number
WO2014083693A1
WO2014083693A1 PCT/JP2012/081137 JP2012081137W WO2014083693A1 WO 2014083693 A1 WO2014083693 A1 WO 2014083693A1 JP 2012081137 W JP2012081137 W JP 2012081137W WO 2014083693 A1 WO2014083693 A1 WO 2014083693A1
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layer
light
light emitting
electrode
organic functional
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PCT/JP2012/081137
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English (en)
Japanese (ja)
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黒田　和男
秀雄 工藤
浩 大畑
敏治 内田
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パイオニア株式会社
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Priority to PCT/JP2012/081137 priority Critical patent/WO2014083693A1/fr
Publication of WO2014083693A1 publication Critical patent/WO2014083693A1/fr

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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
    • H10K59/875—Arrangements for extracting light from the devices
    • H10K59/878—Arrangements for extracting light from the devices comprising reflective means

Definitions

  • the present invention relates to a light emitting device having an organic light emitting layer.
  • a light emitting device having an organic light emitting layer as one of the light emitting devices.
  • this light emitting device it is desired to improve the ratio of light emitted to the outside (light extraction efficiency) of the light generated in the organic light emitting layer.
  • Patent Document 1 As a technique for improving the light extraction efficiency, there is one described in Patent Document 1.
  • the organic EL (Electro Luminescence) element described in Patent Document 1 emits light with respect to a light-transmitting front electrode and back electrode, a light-emitting layer disposed between the front electrode and the back electrode, and the back electrode as a reference.
  • a high refractive index light scattering layer disposed on the opposite side of the layer.
  • the high refractive index light scattering layer is constituted by dispersing fine particles such as Y 2 O 3 in a resin.
  • Japanese Patent Application Laid-Open No. H10-228707 describes that light traveling from the light emitting layer toward the back side is reflected by the high refractive index light scattering layer and travels toward the front side, so that light can be efficiently extracted from the front side.
  • Patent Document 1 The inventor considered that the technique described in Patent Document 1 has the following problems.
  • the high refractive index light scattering layer in the technique of Patent Document 1 scatters light in a random direction. For this reason, the effect of strengthening the intensity of light reflected by the high-refractive-index light scattering layer and reflected toward the front side (reflected light) and the light directed from the light emitting layer toward the front side (direct light) is sufficient. It is difficult to get into. Therefore, the technique of Patent Document 1 has room for improvement regarding light extraction efficiency. Furthermore, a problem peculiar to the scattering layer is that in the case of light in an oblique direction, the probability of scattering increases, and the amount of light toward the extraction surface decreases.
  • An example of a problem to be solved by the present invention is to improve the light extraction efficiency of the light emitting device.
  • the invention according to claim 1 is a translucent substrate; A translucent first electrode disposed on the side opposite to the exit surface of the translucent substrate; An organic functional layer including at least a light-emitting layer and disposed on the opposite side of the translucent substrate with respect to the first electrode; A light reflecting layer disposed on the opposite side of the first electrode with respect to the organic functional layer, and reflecting light coming from the organic functional layer side; A light-transmitting intervening layer disposed between the organic functional layer and the light reflecting layer; With The intervening layer is formed by laminating three or more layers having different refractive indexes between adjacent layers, and has two or more interfaces. In the light emitting device, the refractive indexes of the three or more layers are alternately high and low or alternately low and high from the organic functional layer side toward the light reflecting layer side. is there.
  • FIG. 8A is a plan view showing an example of a more specific configuration of the light emitting device according to the first embodiment
  • FIG. 8B is a cross-sectional view taken along line BB in FIG. 8A.
  • 1 is a cross-sectional view illustrating a configuration of a light emitting device according to Example 1.
  • FIG. 6 is a cross-sectional view illustrating a configuration of a light emitting device according to Example 2.
  • FIG. 6 is a cross-sectional view illustrating a configuration of a light emitting device according to Example 3.
  • FIG. 6 is a cross-sectional view illustrating a configuration of a light emitting device according to Example 4.
  • FIG. 1 is a cross-sectional view showing a configuration of a light emitting device 100 according to an embodiment.
  • the light emitting device 100 includes an organic EL element.
  • the light emitting device 100 can be used as a light source of, for example, a display, a lighting device, or an optical communication device.
  • the light emitting device 100 includes a light transmissive substrate 110 having an emission surface (light extraction surface 110a), a light transmissive first electrode 130, an organic functional layer 140 including at least a light emitting layer, and light reflection.
  • the first electrode 130 is disposed on the side opposite to the emission surface of the translucent substrate 110.
  • the organic functional layer 140 is disposed on the opposite side of the translucent substrate 110 with respect to the first electrode 130.
  • the light reflecting layer 160 is disposed on the side opposite to the first electrode 130 with respect to the organic functional layer 140.
  • the light reflecting layer 160 reflects light that arrives at the light reflecting layer 160 from the organic functional layer 140 side.
  • the intervening layer 120 is disposed between the organic functional layer 140 and the light reflecting layer 160.
  • the intervening layer 120 is configured by stacking three or more layers having different refractive indexes between adjacent layers, and has two or more interfaces.
  • the refractive indexes of three or more layers constituting the intervening layer 120 are alternately in the order of high and low from the organic functional layer 140 side to the light reflecting layer 160 side, or alternately low and high. The order is
  • the translucent substrate 110 is a plate-like member made of a translucent material such as glass or resin.
  • the upper surface of the translucent substrate 110 that is, the surface of the translucent substrate 110 opposite to the organic functional layer 140 side is a flat light extraction surface 110a.
  • the light extraction surface 110a is in contact with air (refractive index 1) filling the light emission space.
  • the light extraction film is affixed on the upper surface of the translucent board
  • the first electrode 130 may be a transparent electrode made of a metal oxide conductor such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide). However, the first electrode 130 may be a metal thin film that is thin enough to transmit light.
  • a metal oxide conductor such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide).
  • the first electrode 130 may be a metal thin film that is thin enough to transmit light.
  • the organic functional layer 140 includes a translucent second electrode 150.
  • the second electrode 150 is disposed at the end of the organic functional layer 140 on the intervening layer 120 side. That is, the 2nd electrode 150 comprises the layer of the end by the side of the intervening layer 120 in the organic functional layer 140, for example.
  • the organic functional layer 140 includes an organic layer (such as an electron injection layer) disposed between the second electrode 150 and the intervening layer 120. That is, the second electrode 150 is disposed at an intermediate portion in the thickness direction of the organic functional layer 140.
  • FIG. 1 shows an example in which the second electrode 150 is disposed at the end of the organic functional layer 140 on the intervening layer 120 side.
  • the second electrode 150 can be a metal thin film that is thin enough to transmit light.
  • the film thickness of the second electrode 150 can be about 10 nm, for example.
  • the material of the second electrode 150 include silver and aluminum.
  • the second electrode 150 may be a transparent electrode made of a metal oxide conductor such as ITO or IZO.
  • the first electrode 130 constitutes an anode and the second electrode 150 constitutes a cathode.
  • the material of the second electrode 150 and the material of the first electrode 130 it is necessary to select a combination of the material of the second electrode 150 and the material of the first electrode 130 so that the work function of the second electrode 150 is smaller than the work function of the first electrode 130.
  • the portion other than the second electrode 150 in the organic functional layer 140 is made of an organic material such as NPB (N, N-di (naphthalene-1-yl) -N, N-diphenyl-benzidine).
  • the organic functional layer 140 may include, for example, a layer having an electron transport function, a layer having a hole transport function, and the like in addition to the light emitting layer.
  • the refractive index of the organic functional layer 140 is, for example, about 1.6 or more and 2.0 or less.
  • Each layer constituting the intervening layer 120 is made of, for example, a translucent dielectric. Of the three or more layers constituting the intervening layer 120, adjacent layers are in contact with each other, and an interface is formed between the adjacent layers.
  • the intervening layer 120 has a laminated structure in which three or more first layers 121 and second layers 122 are alternately laminated.
  • the refractive index of the second layer 122 is smaller than the refractive index of the first layer 121.
  • the refractive index of the first layer 121 is equal to or higher than the refractive index of the organic functional layer 140.
  • the refractive index of the first layer 121 can be about 1.8.
  • the refractive index of the second layer 122 can be about 1.3 to 1.5.
  • the material of the first layer 121 can be the same as the material of the organic functional layer 140, for example.
  • the material of the second layer 122 can be, for example, MgF 2 (refractive index 1.37) or SiO 2 (refractive index 1.45). Note that the first layers 121 are not necessarily made of the same material. Similarly, the second layers 122 are not necessarily made of the same material. If the refractive index inside the intervening layer 120 is alternately in the order of high and low from the organic functional layer 140 side to the light reflecting layer 160 side, or alternately in the order of low and high.
  • any refractive index material may be used as the material of the first layer 121 and the second layer 122. If the refractive index inside the intervening layer 120 is alternately in the order of high and low from the organic functional layer 140 side to the light reflecting layer 160 side, or alternately in the order of low and high.
  • the refractive index of any one or more second layers 122 may be larger than the refractive index of any one or more first layers 121.
  • the refractive indexes of the first layers 121 are different from each other, the physical film thicknesses of the first layers 121 are different from each other even if the optical path lengths of the film thicknesses of the first layers 121 are the same.
  • the refractive indexes of the second layers 122 are different from each other, even if the optical path lengths of the film thicknesses of the second layers 122 are the same, the physical film thicknesses of the second layers 122 are different from each other.
  • a material that does not adversely affect the organic functional layer 140 for example, porous silica
  • a material that adversely affects the organic functional layer 140 when it is close to the organic functional layer 140 should be selected. Can do. This is because the first layer 121 and the second layer 122 existing between the first layer 121 and the second layer 122 and the organic functional layer 140 serve as a barrier layer.
  • the uppermost layer (most layer on the organic functional layer 140 side) in the intervening layer 120 may be either the first layer 121 or the second layer 122. However, even if the second electrode 150 is disposed at the end of the organic functional layer 140 on the side of the intervening layer 120 by suppressing the uppermost layer of the intervening layer 120 to the first layer 121 having a high refractive index, the occurrence of plasmon resonance is suppressed. can do. On the other hand, when the uppermost layer in the intervening layer 120 is the second layer 122 having a low refractive index, the interface between the second electrode 150 and the intervening layer 120 has a high refractive index from the light emitting layer side toward the light reflecting layer 160 side.
  • the interface changes from one side to the other, and light can be reflected to the light extraction surface 110a side at this interface.
  • the lowermost layer (the layer closest to the light reflecting layer 160) in the intervening layer 120 may be either the first layer 121 or the second layer 122.
  • the light reflecting layer 160 is made of, for example, a metal film such as silver or aluminum. That is, the light reflection layer 160 is, for example, conductive.
  • the light reflecting layer 160 reflects light traveling from the organic functional layer 140 toward the light reflecting layer 160 (light coming from the organic functional layer 140 side) toward the translucent substrate 110 side.
  • the light reflection layer 160 may be non-conductive (insulating). For this reason, the light reflection layer 160 may not be a metal layer.
  • the light emitting layer of the organic functional layer 140 When a voltage is applied between the first electrode 130 and the second electrode 150, the light emitting layer of the organic functional layer 140 emits light.
  • the translucent substrate 110, the first electrode 130, the organic functional layer 140, the second electrode 150, and the first layer 121 and the second layer 122 of the intervening layer 120 are all light emitted from the light emitting layer of the organic functional layer 140. Of at least part of it. Part of the light emitted from the light emitting layer is emitted (extracted) from the light extraction surface 110a of the translucent substrate 110 to the outside of the light emitting device 100 (that is, the light emission space).
  • one surface (the lower surface in FIG. 1) of the translucent substrate 110 and one surface (the upper surface in FIG. 1) of the first electrode 130 are in contact with each other.
  • the other surface (lower surface in FIG. 1) of the first electrode 130 and one surface (upper surface in FIG. 1) of the organic functional layer 140 are in contact with each other.
  • the second electrode 150 is disposed at the end of the organic functional layer 140 on the intervening layer 120 side.
  • the second electrode 150 and one surface (the upper surface in FIG. 1) of the intervening layer 120 are in contact with each other. More specifically, the surface of the second electrode 150 opposite to the light emitting layer side and one surface (the upper surface in FIG. 1) of the uppermost first layer 121 are in contact with each other.
  • the other surface (lower surface in FIG. 1) of the intervening layer 120 and one surface (upper surface in FIG. 1) of the light reflecting layer 160 are in contact with each other. More specifically, one surface (the lower surface in FIG. 1) of the lowermost first layer 121 and one surface of the light reflecting layer 160 are in contact with each other.
  • another layer may exist between the translucent substrate 110 and the first electrode 130.
  • another layer may exist between the first electrode 130 and the organic functional layer 140.
  • another layer may exist between the organic layer (organic material part) such as an electron injection layer and the second electrode 150.
  • another layer may exist between the second electrode 150 and the intervening layer 120.
  • another layer may exist between the intervening layer 120 and the light reflecting layer 160.
  • the thickness of each of the three or more layers constituting the intervening layer 120 is such that the optical path length (optical distance) is ⁇ / 4. Yes. That is, the thickness of each first layer 121 and the thickness of each second layer 122 are such that the optical path length (optical distance) is ⁇ / 4.
  • the maximum peak wavelength ⁇ differs individually depending on the refractive index of each layer. That is, the maximum peak wavelength ⁇ is a value for each layer.
  • the thickness of the first layer 121 is lambda 1/4
  • the film thickness of the second layer is lambda 2/4.
  • the optical path length (optical distance) from the light emitting surface to the interface between the organic functional layer 140 and the intervening layer 120 is a multiple of ⁇ / 2. It has become.
  • the basic unit of light is considered to be one wavelength
  • the minimum light emitting region (the lower limit of the size of the region where light emission occurs) is a spherical region having a diameter ⁇ . If the central point of the minimum light emitting region is referred to as the light emitting center point, the light emitting surface is a substantially flat surface composed of a set of light emitting center points.
  • the film thickness of the light emitting layer is about 25 nm or more and 35 nm or less
  • the light emitting surface exists, for example, at a position of about 5 nm from the hole injection layer, depending on conditions.
  • the optical path length from the light emitting surface to the interface between the organic functional layer 140 and the intervening layer 120 in the light emitting layer depends on the refractive index of each layer interposed between the light emitting surface and the interface between the organic functional layer 140 and the interposing layer 120. It becomes length.
  • FIG. 1 shows an example in which the uppermost layer and the lowermost layer of the intervening layer 120 are both the first layer 121, and the following operation description is based on this structure.
  • FIG. 2 is a cross-sectional view showing an example of the operation of the light emitting device 100 according to the first embodiment.
  • the light traveling toward the translucent substrate 110 (the light of the optical paths L1 and L5) travels toward the translucent substrate 110 through the organic functional layer 140 and the first electrode 130.
  • the refractive index of the first electrode 130 is 1.8, for example, and the refractive index of the translucent substrate 110 is 1.5, for example.
  • the light is totally reflected at the interface with the substrate 110 and the remaining light is transmitted (incident) to the light transmitting substrate 110. Part of the light transmitted (incident) to the translucent substrate 110 is totally reflected at the interface with the light emission space, and the rest is emitted to the light emission space.
  • the light whose angle between the normal to the organic functional layer 140 and the optical axis is within a predetermined angle ⁇ is any one of the first layers 121 and the second layer adjacent thereto.
  • the light is reflected at the interface with 122 and synthesized, and acts as if large reflection is occurring at the interface between the organic functional layer 140 and the intervening layer 120.
  • the film thickness of each layer constituting the intervening layer 120 (the film thickness of each first layer 121 and the film thickness of each second layer 122) is a film whose optical path length is ⁇ / 4, respectively.
  • the film thickness of each first layer 121 and the film thickness of each second layer 122 are ⁇ / 4, respectively, with respect to light having a certain angle or less (light within an angle ⁇ )
  • Light reflected at each interface between the first layer 121 and the second layer 122 reinforces each other due to interference. Thereby, the light extraction efficiency can be improved. Note that the effect of strengthening the reflected light in this way increases as the number of layers constituting the intervening layer 120 increases.
  • the thickness of each first layer 121 and the thickness of each second layer 122 are ⁇ / 4, and the lowest layer of the intervening layer 120 is the first layer 121.
  • the optical path length from the light emitting surface of the light emitting layer to the interface between the organic functional layer 140 and the intervening layer 120 is a multiple of ⁇ / 2, light with a certain angle or less (light within an angle ⁇ )
  • these lights can be intensified.
  • the light extraction efficiency is improved by the amount of reflected light at the interface between the organic functional layer 140 and the intervening layer 120.
  • FIG. 3 is a diagram showing a simulation result of the reflectance in the light emitting device 100 according to the first embodiment.
  • the maximum peak wavelength ⁇ of light emitted from the light emitting layer is 520 nm with respect to the light emitting device 100 including the intervening layer 120 in which six first layers 121 and five second layers 122 are alternately stacked. It was carried out as As shown in FIG. 3, the angle between the normal to the organic functional layer 140 and the optical axis is within about 20 degrees (corresponding to the angle ⁇ ), and the angle is about 60 degrees (corresponding to ⁇ ) or more. It can be seen that a remarkably high reflectance (almost 100%) can be obtained with respect to the above light.
  • FIG. 4 is a diagram illustrating interference between direct light from the light emitting layer and reflected light reflected by the second electrode 150 in the light emitting device according to the comparative example.
  • the light emitting device according to the comparative example is different from the light emitting device 100 shown in FIG. 1 in that the intervening layer 120 and the light reflecting layer 160 are not provided and the second electrode 150 is a reflecting electrode. Then, it shall be comprised similarly to the light-emitting device 100 shown in FIG. That is, in the light emitting device according to Comparative Example 1, the intervening layer 120 does not exist between the light reflecting layer (second electrode 150) and the organic functional layer 140.
  • a part of the light emitted from the light emitting layer is directed toward the translucent substrate 110 as indicated by an optical path L21 in FIG.
  • Another part of the light emitted from the light emitting layer is directed to the second electrode 150 side as indicated by the optical path L22, reflected at the interface between the organic functional layer 140 and the second electrode 150, and indicated by the optical path 23. In this way, it goes to the translucent substrate 110 side.
  • the light indicated by the optical path L21 (direct light) and the light indicated by the optical path L23 (reflected light) interfere with each other to increase or decrease (increase or decrease) the intensity of the light.
  • FIG. 5 is a diagram showing the relationship between the light angle and the increase / decrease in light intensity due to interference in the light emitting device according to the comparative example.
  • the horizontal axis represents the light angle
  • the vertical axis represents the light intensity.
  • the angle of light on the horizontal axis is the angle formed between the normal to the light extraction surface 110a and the optical path.
  • the light intensity on the vertical axis is a simulation result of the light intensity after the interference, and the light intensity before the interference (the light intensity on the optical path L21) is 1.
  • the light intensity shown in FIG. 5 is a simulation result when the distance from the light emitting layer to the second electrode 150 is set so that the light intensity after interference is the strongest when the light angle is 0 degree. is there. In this case, as shown in FIG. 5, as the light angle increases, the light intensity decreases due to the influence of interference.
  • the intervening layer 120 exists between the organic functional layer 140 including the light emitting layer and the light reflecting layer (light reflecting layer 160).
  • the reflected light and the reflected light are reflected as the light is reflected at the interface far from the light emitting layer.
  • the influence of interference between the light and the corresponding direct light can be suppressed. This is because the optical axis of the reflected light and the optical axis of the direct light are further away as the light is reflected at the interface far from the light emitting layer.
  • the intervening layer 120 having a structure in which the first layer 121 and the second layer 122 are provided in multiple layers as in the present embodiment, the reflected light of the light having a certain angle or more and the direct light interfere with each other. Can suppress mutual weakening. Therefore, the light extraction efficiency is improved as compared with the comparative example.
  • a light-transmitting conductive film made of a metal oxide conductor such as ITO or IZO is formed on the lower surface of the light-transmitting substrate 110 by sputtering or the like, and patterned by etching to form the first electrode 130. Form.
  • the organic functional layer 140 is formed by applying an organic material to the lower surface of the first electrode 130.
  • a second electrode 150 is formed on the lower surface of the organic functional layer 140 by depositing a metal material such as Al by vapor deposition or the like.
  • an organic material such as NPB is applied to the lower surface of the second electrode 150 to form the uppermost first layer 121 in the intervening layer 120.
  • the uppermost layer of the second layer 122 is formed on the lower surface of the uppermost first layer 121 by using MgF 2 or SiO 2 .
  • the first layer 121 and the second layer 122 are alternately formed. Then, the first layer 121 is formed as the lowermost layer of the intervening layer 120.
  • a light reflecting layer 160 is formed by depositing a metal material such as Al on the lower surface of the intervening layer 120 by vapor deposition or the like.
  • FIG. 6 is a diagram illustrating a first example of the layer structure of the organic functional layer 140.
  • the organic functional layer 140 according to the first example has a structure in which a hole injection layer 141, a hole transport layer 142, a light emitting layer 143, an electron transport layer 144, and an electron injection layer 145 are stacked in this order. That is, the organic functional layer 140 is an organic electroluminescence light emitting layer. Note that instead of the hole injection layer 141 and the hole transport layer 142, one layer having the functions of these two layers may be provided. Similarly, instead of the electron transport layer 144 and the electron injection layer 145, one layer having the function of these two layers may be provided (see FIG. 8B).
  • the light emitting layer 143 is, for example, a layer that emits red light, a layer that emits blue light, a layer that emits yellow light, or a layer that emits green light. .
  • a region having a light emitting layer 143 that emits red light, a region having a light emitting layer 143 that emits green light, and a region having a light emitting layer 143 that emits blue light are repeatedly provided. (See FIG. 8B).
  • the light emitting device 100 emits light in a single light emission color such as white.
  • the light emitting layer 143 may be configured to emit light in a single light emission color such as white by mixing materials for emitting a plurality of colors.
  • FIG. 7 is a diagram illustrating a second example of the layer structure of the organic functional layer 140.
  • FIG. 8 (described later) describes an example in which regions separated from each other by the partition wall portion 180 in the organic functional layer 140 emit red light, green light, and blue light, respectively.
  • the light emitting layer 143 of the organic functional layer 140 has a configuration in which the light emitting layers 143a, 143b, and 143c are stacked in this order.
  • the light emitting layers 143a, 143b, and 143c emit light of different colors (for example, red, green, and blue).
  • the light emitting layers 143a, 143b, and 143c emit light at the same time, so that the light emitting device 100 emits light in a single light emission color such as white.
  • FIG. 8A is a plan view showing an example of a more specific configuration of the light emitting device 100 according to the embodiment
  • FIG. 8B is a cross-sectional view taken along line BB in FIG. 8A. is there. 8B and 8A are upside down with respect to FIG.
  • the first electrode 130 constitutes an anode.
  • the plurality of first electrodes 130 each extend in the Y direction in a strip shape. Adjacent first electrodes 130 are spaced apart from each other at a constant interval in the X direction orthogonal to the Y direction.
  • Each of the first electrodes 130 is made of a metal oxide conductor such as ITO or IZO, for example.
  • the refractive index of the first electrode 130 is approximately the same as that of the first layer 121 (for example, approximately 1.8).
  • a bus line (bus electrode) 170 for supplying a power supply voltage to the first electrode 130 is formed on each surface of the first electrode 130.
  • An insulating film is formed on the translucent substrate 110 and the first electrode 130.
  • a plurality of stripe-shaped openings each extending in the Y direction are formed.
  • a plurality of partition walls 180 made of an insulating film are formed.
  • Each of the openings formed in the insulating film reaches the first electrode 130, and the surface of each first electrode 130 is exposed at the bottom of the opening.
  • An organic functional layer 140 is formed on the first electrode 130 in each opening of the insulating film.
  • the organic material portion of the organic functional layer 140 is configured by laminating a hole injection layer 141, a hole transport layer 142, a light emitting layer 143 (light emitting layers 143R, 143G, 143B), and an electron transport layer 144 in this order. ing.
  • Materials for the hole injection layer 141 and the hole transport layer 142 include aromatic amine derivatives, phthalocyanine derivatives, porphyrin derivatives, oligothiophene derivatives, polythiophene derivatives, benzylphenyl derivatives, compounds in which tertiary amines are linked by fluorene groups, hydrazones. Derivatives, silazane derivatives, silanamine derivatives, phosphamine derivatives, quinacridone derivatives, polyaniline derivatives, polypyrrole derivatives, polyphenylene vinylene derivatives, polythienylene vinylene derivatives, polyquinoline derivatives, polyquinoxaline derivatives, carbon and the like.
  • the light emitting layers 143R, 143G, and 143B are made of a fluorescent organometallic compound that emits red light, green light, and blue light, respectively.
  • the light emitting layers 143R, 143G, and 143B are arranged side by side in a state of being separated from each other by the partition wall portion 180. That is, the organic functional layer 140 is partitioned into a plurality of regions by the partition wall portion 180.
  • An electron transport layer 144 is formed so as to cover the surfaces of the light emitting layers 143R, 143G, and 143B and the partition wall portion 180.
  • a second electrode 150 is formed so as to cover the surface of the electron transport layer 144.
  • the second electrode 150 constitutes a cathode.
  • the second electrode 150 is formed in a band shape.
  • the second electrode 150 is made of a metal such as Al or an alloy having a low work function and high reflectivity.
  • the refractive index of the organic material portion of the organic functional layer 140 is approximately the same as that of the first electrode 130 and the first layer 121 (for example, a refractive index of approximately 1.8).
  • An intervening layer 120 is formed on the second electrode 150.
  • a light reflecting layer 160 is formed on the intervening layer 120.
  • the light emitting layers 143R, 143G, and 143B that emit red, green, and blue light are repeatedly arranged in a stripe shape, and red, Green and blue light are mixed at an arbitrary ratio to emit light that is recognized as a single emission color (for example, white).
  • the light emitting device 100 includes the translucent intervening layer 120 disposed between the organic functional layer 140 and the light reflecting layer 160.
  • the intervening layer 120 is formed by laminating three or more layers having different refractive indexes between adjacent layers, and has two or more interfaces.
  • the refractive indexes of three or more layers constituting the intervening layer 120 are alternately in the order of high and low from the organic functional layer 140 side to the light reflecting layer 160 side, or alternately low. , In order of high. Therefore, the optical path length of the light (reflected light) from the organic functional layer 140 toward the light reflecting layer 160 toward the light reflecting layer 160 and then toward the light transmitting substrate 110 is passed through the intervening layer 120. Can earn by.
  • the refractive index of the intervening layer 120 is uniform, the light traveling from the organic functional layer 140 toward the light reflecting layer 160 is reflected by the light reflecting layer 160 that is a metal layer and travels toward the light transmitting substrate 110 side. Head. However, a certain amount of loss occurs in the reflection at the metal layer.
  • the refractive index of the second layer 122 is smaller than the refractive index of the first layer 121, a part of the light traveling from the organic functional layer 140 toward the light reflecting layer 160 is Total reflection can be performed at the interface between the first layer 121 and the second layer 122. Thereby, since the loss can be reduced as compared with the case where the refractive index of the intervening layer 120 is uniform, the light extraction efficiency is improved.
  • the uppermost layer of the intervening layer 120 is the first layer 121 having a high refractive index.
  • the second electrode 150 made of a metal thin film exists at the end of the organic functional layer 140 on the side of the intervening layer 120, the second electrode 150 and the first layer 121 are in contact with each other even if the second electrode 150 and the first layer 121 are in contact with each other.
  • Evanescent light and plasmon resonance do not occur at the interface with the first layer 121. Thereby, the fall of light extraction efficiency can be suppressed.
  • the second electrode 150 is the intervening layer in the organic functional layer 140.
  • the same effect can be obtained by disposing the second electrode 150 at the intermediate portion in the thickness direction of the organic functional layer 140 instead of disposing it at the end on the 120 side.
  • the light is reflected at the interface between the organic functional layer 140 and the intervening layer 120 for light having a certain angle or less. Therefore, the reflected light reflected at the interface between the organic functional layer 140 and the intervening layer 120 and the light on the light emitting surface can be made to interfere with each other. Thereby, the light extraction efficiency can be improved.
  • each layer (three or more layers) constituting the intervening layer 120 is such that the optical path length is ⁇ / 4, the light reflected at the interface of each layer constituting the intervening layer 120 Amplify by interfering with each other. Therefore, the intensity of light extracted from the light emitting device 100 can be improved.
  • the optical path length from the light emitting surface in the light emitting layer to the interface between the organic functional layer 140 and the intervening layer 120 is a multiple of ⁇ / 2
  • the light is reflected at the interface between the organic functional layer 140 and the intervening layer 120.
  • the phases of light and direct light from the light emitting surface of the light emitting layer toward the translucent substrate 110 can be matched, and these light can be amplified by interfering with each other. Therefore, the intensity of light extracted from the light emitting device 100 can be improved.
  • the organic functional layer 140 includes the translucent second electrode 150, it is possible to easily apply a voltage to the light emitting layer in the organic functional layer 140.
  • the second electrode 150 may be drawn out to the peripheral portion of the light emitting device 100 in plan view, and a voltage may be applied to the drawn portion.
  • FIG. 9 is a cross-sectional view showing the configuration of the light emitting device 100 according to the second embodiment.
  • the light emitting device 100 according to the second embodiment is different from the light emitting device 100 according to the first embodiment (FIG. 1) in the points described below, and in other points, the light emitting device according to the first embodiment.
  • the configuration is the same as that of the apparatus 100.
  • the light emitting device 100 according to the second embodiment does not have the second electrode 150 in the organic functional layer 140.
  • the lower surface of the lowermost organic layer (for example, the electron injection layer 145) in the organic functional layer 140 and the upper surface of the intervening layer 120 (the upper surface of the uppermost first layer 121) are in contact with each other.
  • another layer may exist between the organic functional layer 140 and the intervening layer 120.
  • the light reflecting layer 160 is conductive.
  • the light reflecting layer 160 also functions as a cathode.
  • the organic functional layer 140 includes a hole transport layer disposed on the first electrode 130 side of the light emitting layer.
  • the organic functional layer 140 includes a hole injection layer 141 and a hole transport layer 142 similarly to the configuration illustrated in FIG.
  • each first layer 121 and each second layer 122 have an electron transport function. That is, each first layer 121 and each second layer 122 function as an electron transport layer.
  • Each first layer 121 and each second layer 122 may function as an electron transport layer and an electron injection layer.
  • the intervening layer 120 also functions as a part of the organic functional layer 140. Therefore, in the case of this embodiment, the organic functional layer 140 does not need to have an electron carrying layer and an electron injection layer.
  • the light emitting layer of the organic functional layer 140 when a voltage is applied between the first electrode 130 and the light reflecting layer 160, the light emitting layer of the organic functional layer 140 emits light.
  • the organic functional layer 140 contains the electron carrying layer arrange
  • the organic functional layer 140 includes an electron injection layer and an electron transport layer.
  • Each first layer 121 and each second layer 122 have a hole transport function.
  • each first layer 121 and each second layer 122 may function as a hole transport layer and a hole injection layer.
  • the organic functional layer 140 does not need to have a positive hole transport layer and a positive hole injection layer.
  • the second electrode 150 since the second electrode 150 is not present, when the refractive indexes of the layers sandwiching the metal film (the layers on both sides of the metal film) are different from each other (one of the layers sandwiching the metal layer is relatively low). Evanescent light and plasmon resonance generated at the interface between the metal film and the low refractive index layer do not occur in the refractive index layer (when the other is a relatively high refractive index layer).
  • the light emitting device 100 does not have the second electrode 150.
  • the light emitting layer can emit light by applying a voltage to the organic functional layer 140.
  • FIG. 10 is a cross-sectional view illustrating a configuration of the light emitting device 100 according to the first embodiment.
  • the light emitting device 100 according to Example 1 is different from the light emitting device 100 according to the first embodiment (FIG. 1) in the points described below, and otherwise the light emitting device 100 according to the first embodiment. It is configured in the same way.
  • the light scattering layer 210 is provided between the intervening layer 120 and the light reflecting layer 160.
  • the lower surface of the intervening layer 120 and the upper surface of the light scattering layer 210 are in contact with each other, and the lower surface of the light scattering layer 210 and the upper surface of the light reflecting layer 160 are in contact with each other.
  • other layers may exist between the intervening layer 120 and the light scattering layer 210 and between the light scattering layer 210 and the light reflecting layer 160, respectively.
  • the light scattering layer 210 includes, for example, a base material made of a dielectric material and particles disposed in the base material with a refractive index smaller than that of the base material.
  • a plurality of (many) particles are contained in the substrate.
  • Particles for example, inorganic particles such as SiO 2.
  • the size of the particles is preferably not less than the peak wavelength (maximum peak wavelength) ⁇ of the emission wavelength from the light emitting layer.
  • the particle size means the sphere equivalent diameter of each particle.
  • the particles may be spherical, where the particle size is the particle diameter.
  • the shape of the particles may be any other shape.
  • Example 1 a part of the light traveling from the intervening layer 120 toward the light reflecting layer 160 side is scattered in a random direction by the light scattering layer 210. Accordingly, it can be expected that a part of light having an angle that is not emitted from the light emitting device 100 when the light scattering layer 210 is not present can be extracted from the light emitting device 100.
  • FIG. 11 is a cross-sectional view illustrating a configuration of the light emitting device 100 according to the second embodiment.
  • the light emitting device 100 according to Example 2 is different from the light emitting device 100 according to the first embodiment (FIG. 1) in the points described below, and otherwise the light emitting device 100 according to the first embodiment. It is configured in the same way.
  • a first low refractive index layer 147 is disposed between the second electrode 150 and the light emitting layer.
  • the first low refractive index layer 147 is a layer including a first base material and first particles having a refractive index smaller than that of the first base material and disposed in the first base material.
  • a second low refractive index layer 220 is disposed between the second electrode 150 and the intervening layer 120.
  • the second low refractive index layer 220 is a layer including a second base material and second particles having a refractive index smaller than that of the second base material and disposed in the second base material.
  • the materials of the first base material and the second base material are, for example, the same materials as those of the organic functional layer 140 in the first embodiment.
  • the first particles and the second particles are inorganic particles such as SiO 2 and nano silica.
  • the dimensions of the first particles and the second particles may be ⁇ or less.
  • the dimension of the first particle and the second particle can be set to, for example, about 20 nm.
  • grains) means the spherical equivalent diameter of each particle
  • the particles may be spherical, where the particle size is the particle diameter.
  • the shape of the particles may be any other shape.
  • the first low refractive index layer 147 and the second low refractive index layer 220 become the first base material and the first base material. 2
  • the refractive index is lowered compared to the base material. That is, the pair of layers sandwiching the second electrode 150 has a low refractive index.
  • the first low refractive index layer 147 functions as, for example, an electron transport layer, or functions as an electron injection layer and an electron transport layer.
  • the first low refractive index layer 147 functions as, for example, a hole transport layer, or as a hole injection layer and a hole transport layer. Function.
  • the pair of layers (the first low refractive index layer 147 and the second low refractive index layer 220) sandwiching the second electrode 150 each have a low refractive index. Since the light emitting layer has a high refractive index, light can be totally reflected at the interface between the light emitting layer and the first low refractive index layer 147. Accordingly, light having an angle can be directed to the light extraction surface 110a side without using the intervening layer 120 below the second low refractive index layer 220, so that the light extraction efficiency can be improved.
  • FIG. 12 is a cross-sectional view illustrating a configuration of the light emitting device 100 according to the third embodiment.
  • the light emitting device 100 according to Example 3 is different from the light emitting device 100 according to the first embodiment (FIG. 11) in the points described below, and otherwise the light emitting device 100 according to the first embodiment. It is configured in the same way.
  • the light reflection layer 160 is a conductor.
  • the light emitting device 100 includes a conductor 190 that electrically connects at least one second electrode 150 and the light reflection layer 160 to each other. That is, the light emitting device 100 includes one or a plurality of second electrodes 150, and at least one or more second electrodes 150 are electrically connected to the light reflecting layer 160.
  • the conductor 190 penetrates the intervening layer 120 up and down.
  • the conductor 190 may be a columnar shape (that is, a through hole) or a wall shape.
  • a conductor 190 is formed by vapor-depositing a metal such as Ag using a mask, and then the intervening layer 120 is formed.
  • the conductor 190 may be arrange
  • the light reflection layer 160 is conductive, and the second electrode 150 is electrically connected to the light reflection layer 160.
  • the light reflecting layer 160 can form an electrode together with the second electrode 150, so that a voltage can be more easily applied to the light emitting layer in the organic functional layer 140.
  • FIG. 12 illustrates an example in which the conductor 190 electrically connects the second electrode 150 and the light reflecting layer 160 through the inside of the intervening layer 120.
  • the second electrode 150 and the light reflecting layer 160 may be electrically connected to each other through the outside.
  • the former is suitable for a light emitting device having a light emitting layer having a relatively large area
  • the latter is suitable for a light emitting device having a light emitting layer having a relatively small area.
  • an N-type impurity may be introduced into the intervening layer 120 so that the intervening layer 120 becomes a conductive layer. That is, the intervening layer 120 may be an N-doped layer. Even in this case, the light reflection layer 160 made of a conductor can form an electrode together with the second electrode 150. Note that the second electrode 150 may be an anode and the first electrode 130 may be a cathode. In this case, a P-type impurity can be introduced into the intervening layer 120 to make the intervening layer 120 a P-doped layer.
  • FIG. 13 is a cross-sectional view illustrating a configuration of the light emitting device 100 according to the fourth embodiment.
  • the light emitting device 100 according to the fourth embodiment is different from the light emitting device 100 according to the third embodiment (FIG. 12) in the points described below, and is otherwise configured in the same manner as the light emitting device 100 according to the third embodiment. Has been.
  • the upper surface of the light reflecting layer 160 is an uneven surface 161 including a plurality of inclined surfaces inclined with respect to the organic functional layer 140. That is, the surface on the intervening layer 120 side of the light reflecting layer 160 is an uneven surface 161.
  • the dimension of each inclined surface (the maximum dimension of each inclined surface in a plane parallel to each inclined surface) is preferably not less than the peak wavelength (maximum peak wavelength) ⁇ of the emission wavelength from the light emitting layer.
  • the entire surface on the intervening layer 120 side of the light reflecting layer 160 may be the uneven surface 161, or a part of the surface on the interposing layer 120 side of the light reflecting layer 160 may be a flat surface.
  • Example 4 a part of the light traveling from the organic functional layer 140 toward the light reflecting layer 160 is reflected by the light reflecting layer 160.
  • the upper surface of the light reflecting layer 160 is a concavo-convex surface 161 including a plurality of inclined surfaces inclined with respect to the organic functional layer 140, the light emitting device is formed when the upper surface of the light reflecting layer 160 is a flat surface. It can be expected that a part of the light having an angle that cannot be extracted from 100 can be extracted from the light emitting device 100.
  • FIG. 13 illustrates an example in which the surface on the intervening layer 120 side of the light reflecting layer 160 is an uneven surface 161 when the light emitting device 100 includes the second electrode 150.
  • the second electrode 150 is not provided (FIG. 9)
  • the same effect can be obtained even if the surface on the intervening layer 120 side of the light reflecting layer 160 is an uneven surface 161.

Landscapes

  • Electroluminescent Light Sources (AREA)

Abstract

L'invention concerne un dispositif électroluminescent (100) comprenant : un substrat transmettant la lumière (110) ; une première électrode transmettant la lumière (130) disposée à l'opposé de la surface d'émission de lumière (surface d'extraction de lumière (110a)) du substrat transmettant la lumière (110) ; une couche de fonction organique (140) incluant au moins une couche électroluminescente ; une couche de réflexion de lumière (160) ; et une couche d'interposition transmettant la lumière (120). La couche d'interposition(120) est disposée entre la couche de fonction organique (140) et la couche de réflexion de lumière (160). La couche d'interposition (120) est constituée d'une première couche (121) et d'une deuxième couche (122) qui présentent des indices de réfraction mutuellement différents et sont laminées en alternance en trois couches ou plus, la couche d'interposition (120) contenant deux interfaces ou plus.
PCT/JP2012/081137 2012-11-30 2012-11-30 Dispositif électroluminescent WO2014083693A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024022057A1 (fr) * 2022-07-25 2024-02-01 京东方科技集团股份有限公司 Module électroluminescent et dispositif électroluminescent

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11288786A (ja) * 1998-02-04 1999-10-19 Toyota Central Res & Dev Lab Inc 光共振型有機エレクトロルミネッセンス素子
JP2000277266A (ja) * 1999-03-19 2000-10-06 Toyota Central Res & Dev Lab Inc 有機電界発光素子
GB2353400A (en) * 1999-08-20 2001-02-21 Cambridge Display Tech Ltd Multicolour light emitting devices
JP2004152751A (ja) * 2002-10-08 2004-05-27 Pioneer Electronic Corp 有機エレクトロルミネッセンスデバイス
US20040119405A1 (en) * 2002-10-08 2004-06-24 Pioneer Corporation Organic electroluminescence device
KR20050021327A (ko) * 2003-08-27 2005-03-07 가부시키가이샤 히타치 디스프레이즈 고효율 유기 발광 소자
JP2005071919A (ja) * 2003-08-27 2005-03-17 Hitachi Ltd 高効率有機発光素子
WO2006035956A1 (fr) * 2004-09-28 2006-04-06 Toshiba Matsushita Display Technology Co., Ltd. Écran
CN101006586A (zh) * 2004-09-28 2007-07-25 东芝松下显示技术有限公司 显示器

Patent Citations (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6406801B1 (en) * 1998-02-04 2002-06-18 Kabushiki Kaisha Toyota Chuo Kenkyusho Optical resonator type organic electroluminescent element
JPH11288786A (ja) * 1998-02-04 1999-10-19 Toyota Central Res & Dev Lab Inc 光共振型有機エレクトロルミネッセンス素子
JP2000277266A (ja) * 1999-03-19 2000-10-06 Toyota Central Res & Dev Lab Inc 有機電界発光素子
WO2001015246A2 (fr) * 1999-08-20 2001-03-01 Seiko Epson Corporation Dispositif d'emission de lumiere a longueurs d'onde multiples et appareil electronique
AU6581800A (en) * 1999-08-20 2001-03-19 Cambridge Display Technology Limited Multiple-wavelength light emitting device and electronic apparatus
EP1145335A2 (fr) * 1999-08-20 2001-10-17 Seiko Epson Corporation Dispositif d'emission de lumiere a longueurs d'onde multiples et appareil electronique
DE60045185D1 (de) * 1999-08-20 2010-12-16 Cambridge Display Tech Ltd Vorrichtung zur lichtemission bei mehreren wellenlängen
JP2003508876A (ja) * 1999-08-20 2003-03-04 セイコーエプソン株式会社 複数波長発光素子および電子機器
US6639250B1 (en) * 1999-08-20 2003-10-28 Seiko Epson Corporation Multiple-wavelength light emitting device and electronic apparatus
JP4779171B2 (ja) * 1999-08-20 2011-09-28 セイコーエプソン株式会社 複数波長発光素子および電子機器
GB2353400A (en) * 1999-08-20 2001-02-21 Cambridge Display Tech Ltd Multicolour light emitting devices
JP2004152751A (ja) * 2002-10-08 2004-05-27 Pioneer Electronic Corp 有機エレクトロルミネッセンスデバイス
US20040119405A1 (en) * 2002-10-08 2004-06-24 Pioneer Corporation Organic electroluminescence device
CN1592525A (zh) * 2003-08-27 2005-03-09 株式会社日立显示器 高效有机发光元件
US20050236982A1 (en) * 2003-08-27 2005-10-27 Hitachi Displays, Ltd. High-efficiency organic light emitting element
JP2005071919A (ja) * 2003-08-27 2005-03-17 Hitachi Ltd 高効率有機発光素子
KR20050021327A (ko) * 2003-08-27 2005-03-07 가부시키가이샤 히타치 디스프레이즈 고효율 유기 발광 소자
WO2006035956A1 (fr) * 2004-09-28 2006-04-06 Toshiba Matsushita Display Technology Co., Ltd. Écran
TWI279016B (en) * 2004-09-28 2007-04-11 Toshiba Matsushita Display Tec Display
KR20070050451A (ko) * 2004-09-28 2007-05-15 도시바 마쯔시따 디스플레이 테크놀로지 컴퍼니, 리미티드 디스플레이
US20070120464A1 (en) * 2004-09-28 2007-05-31 Satoshi Okutani Display
EP1794798A1 (fr) * 2004-09-28 2007-06-13 Toshiba Matsushita Display Technology Co., Ltd. Écran
CN101006586A (zh) * 2004-09-28 2007-07-25 东芝松下显示技术有限公司 显示器
JP2008515131A (ja) * 2004-09-28 2008-05-08 東芝松下ディスプレイテクノロジー株式会社 表示装置

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024022057A1 (fr) * 2022-07-25 2024-02-01 京东方科技集团股份有限公司 Module électroluminescent et dispositif électroluminescent

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