JP2005259469A - Organic electroluminescence display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL display device which has a high light-emitting extraction efficiency from an organic layer and has a high luminance. <P>SOLUTION: The organic electroluminescence display device 1 comprises a substrate 10, a first electrode 20 provided on the substrate 10, an organic layer 30 provided on the first electrode 20, and a second electrode 40 which has a laminated structure of a metal layer 41 and a transparent layer 42 provided on the organic layer 30. The metal layer 41 is formed in concavo-convex shape at the contact face of the transparent electrode 42. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an organic electroluminescence display device.

  In recent years, with the diversification of information processing equipment, there has been an increasing demand for flat display devices that consume less power than conventional cathode ray tubes (CRTs) and can be reduced in thickness. Examples of such a flat display device include a liquid crystal display device and an electroluminescence display device (hereinafter sometimes abbreviated as “EL display device”). Among them, the organic EL display device has features such as low voltage driving, all solid-state type, high-speed response, and self-luminous property, and therefore, research and development are being actively performed.

  The organic EL display device is largely divided into a passive matrix method (hereinafter abbreviated as “PM method”) and an active matrix method (hereinafter abbreviated as “AM method”) depending on the driving method. Separated.

  Since the PM method is line-sequential driving, in order to obtain high panel luminance, it is necessary to apply a large instantaneous power to each pixel as the display capacity increases, that is, the number of scanning electrodes increases. The organic EL display device of PM type has a problem that the product life is short.

  On the other hand, in the AM method, since switching can be performed for each pixel by a TFT provided for each pixel, the number of scanning electrodes is not limited in principle, and display close to static drive with a duty ratio of 100% can be performed. Enables high-quality and large-capacity display with good panel brightness and response.

  Further, in the AM system, it is not necessary to apply large electric power to each pixel in order to obtain a high panel luminance as in the PM system, and a lower voltage drive and a longer life can be achieved.

  For this reason, in recent years, research and development of AM-type organic EL display devices have been particularly active.

  FIG. 5 is a schematic cross-sectional view of a general organic EL display device 200.

  The organic EL display device 200 includes a substrate 201, an organic layer 203 including a light emitting layer provided on the substrate 201, a first electrode 202 provided so as to sandwich the organic layer 203, and a second electrode. 204.

  The first electrode 202 is configured to be light transmissive and has a function of injecting holes into the organic layer 203. The second electrode 204 is configured to reflect light and has a function of injecting electrons into the organic layer 203.

  The holes and electrons injected from the first electrode 202 and the second electrode 204 recombine in the organic layer 203, whereby the organic layer 203 emits light.

  The organic layer 203 emits light through the first electrode 202 and the substrate 201 and is extracted from the organic EL display device 200 (bottom emission method).

  However, in such an AM type organic EL display device 200, it is necessary to dispose TFTs and electrodes made of silicon or the like that do not transmit light on the substrate 201. Therefore, the ratio of the emission area to the pixel area (opening) There is a problem that the rate is small.

  In particular, a current-driven organic EL display device that can suppress variation in display performance for each pixel and suppress display performance deterioration due to deterioration of a light emitting material is compared with a voltage-driven organic EL display device. More TFTs are required for each pixel. Therefore, the current driving type organic EL display device has a problem that the aperture ratio is further reduced.

  In view of the problem, the second electrode is configured to be light transmissive, and the first electrode is configured to be light reflective so that the organic layer can be formed from the second electrode side opposite to the substrate on which a circuit such as a TFT is configured. A top emission method for taking out the emitted light has been devised (for example, Patent Document 1).

  According to the top emission method, light emitted from the organic layer can be taken out without going through a substrate on which a circuit such as a TFT is formed. This is because a bright organic EL display device can be realized.

In general, in a top emission type organic EL display device, the second electrode has a function as a cathode for injecting electrons into the organic layer, and the second electrode takes out light emission of the organic layer from the second electrode side. The electrode needs to be a light-transmitting electrode with a small work function. Examples of the light-transmitting electrode material include indium tin oxide (hereinafter sometimes abbreviated as “ITO”), but ITO has a large work function and poor electron injection efficiency. Therefore, in general, the second electrode is composed of a transparent electrode layer made of ITO or the like having good light transmittance and high electrical conductivity, and a translucent metal layer having a small work function and high electron injection efficiency. It is composed of a laminated structure.
JP 2001-43980 A

  FIG. 6 is a schematic cross-sectional view of a conventional top emission type organic EL display device 300.

  The organic EL display device 300 includes a substrate 310, an organic layer 330 provided on the substrate 310, a first electrode 320 provided so as to sandwich the organic layer 330, and a second electrode 340. .

  The first electrode 320 has a function of injecting holes into the organic layer 330 and a function of reflecting light emitted from the organic layer 330 toward the first electrode 320 toward the second electrode 340.

  The second electrode 340 includes a metal layer 341 and a transparent electrode layer 342 and has a function of injecting electrons into the organic layer 330. The second electrode 340 is configured to transmit light so that the light emitted from the organic layer 330 can be transmitted and emitted to the viewer side.

  In the organic EL display device 300, the holes injected from the first electrode 320 and the electrons injected from the second electrode 340 are recombined in the organic layer 330, whereby the organic layer 330 emits light. . The light emitted from the organic layer 330 toward the first electrode 320 and reflected by the first electrode 320 and the light emitted from the organic layer 330 toward the second electrode 340 pass through the second electrode 340 and are observed by the observer. To the side.

  In such an organic EL display device 300, the contact surface 343 between the metal layer 341 and the transparent electrode layer 342 constituting the second electrode 340 and the observer-side surface 344 of the transparent electrode layer 342 are formed in a planar shape. Yes. Therefore, a part of the light emission of the organic layer 330 is interface-reflected by the contact surface 343 and the observer-side surface 344 and is incident on the organic layer 330 again. A part of the light incident on the organic layer 330 again is reflected to the viewer side again by the first electrode 320 configured to reflect light, and a part of the reflected light passes through the organic layer 330 and the second electrode 340. Although most of the light is transmitted to the viewer side, most of the light is absorbed by the organic layer 330 or the like. Therefore, the organic EL display device 300 has a problem that the light extraction efficiency from the organic layer 330 is low.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a high-brightness organic EL display device having high emission extraction efficiency from an organic layer.

An organic EL display device according to the present invention includes a substrate, a first electrode provided on the substrate, an organic layer including a light emitting layer provided on the first electrode, and provided on the organic layer. And a second electrode having a laminated structure of a light transmissive metal layer and a transparent electrode layer, and a top emission type organic electroluminescence display device for taking out light emitted from the organic layer from the second electrode side. ,
The metal layer has a concavo-convex shape in contact surface with the transparent electrode layer.

  In the organic EL display device of the present invention, an uneven shape is formed on the contact surface between the metal layer and the transparent electrode layer. According to this configuration, the contact surface acts as a thin layer having intermediate optical characteristics between the metal layer and the transparent electrode layer, and the refractive index of light emitted from the light emitting layer gradually changes at the contact surface. Therefore, the light emission of the organic layer can suppress the interface reflection generated at the contact surface between the metal layer and the transparent electrode layer, and the light emission of the organic layer can be efficiently taken out to the observer side. Therefore, a high-brightness organic EL display device can be realized.

  The organic EL display device according to the present invention has an arithmetic average roughness defined by JIS B 0601-1994 of the contact surface of the metal layer with the transparent electrode layer, which is 1 / of the maximum layer thickness of the metal layer. It is preferably 5 or more and 1/2 or less.

  The arithmetic average roughness (hereinafter abbreviated as “Ra”) defined by JIS B 0601-1994 of the contact surface of the metal layer provided with the uneven shape is 1 of the maximum thickness of the metal layer. In the case of / 5 or more and 1/2 or less, the interface reflection which generate | occur | produces in the contact surface of a metal layer and a transparent electrode layer can be suppressed more effectively. Therefore, the light emission of the organic layer can be efficiently taken out to the observer side. Therefore, an organic EL display device with higher brightness can be realized.

  In the organic EL display device according to the present invention, the maximum thickness of the metal layer is preferably 1 nm or more and 20 nm or less.

  The electron injection efficiency into the organic layer correlates with the maximum thickness of the metal layer, and the electron injection efficiency is low when the maximum thickness of the metal layer is less than 1 nm. On the other hand, in this configuration, since the maximum thickness of the metal layer is as thick as 1 nm or more, high electron injection efficiency can be realized.

  Further, since the metal used for the metal layer generally has a low light transmittance, when the maximum thickness of the metal layer is larger than 20 nm, the light transmittance of the metal layer becomes extremely low. On the other hand, in this configuration, since the maximum thickness of the metal layer is 20 nm or less, the metal layer has high light transmittance.

  Therefore, according to this configuration, the light emission efficiency of the organic layer is good, and the light emission of the organic layer can be extracted with high efficiency. Therefore, an organic EL display device with higher brightness can be realized.

  In the organic EL display device according to the present invention, the metal layer includes one or more metals having a work function of 3.5 eV or more and one or more metals having a work function of less than 3.5 eV. It may be made of an alloy.

  According to this configuration, since the metal layer contains a metal having a low work function of less than 3.5 eV (hereinafter, sometimes abbreviated as “low work function metal”), high electron injection efficiency into the organic layer is achieved. Have. Therefore, according to this configuration, it is possible to realize an organic EL display device with high luminous efficiency of the organic layer and high luminance.

  A low work function metal generally has a property of being easily oxidized. When the low work function metal is oxidized, the electron injection efficiency of the metal layer into the organic layer is lowered. On the other hand, a metal having a high work function (hereinafter sometimes abbreviated as “high work function metal”) generally has a property of being hardly oxidized. Therefore, by making the low work function metal an alloy with the high work function metal, the low work function metal can be shielded from oxygen by the high work function metal. Therefore, in this configuration, oxidation of the low work function metal is suppressed, high electron injection efficiency into the organic layer can be maintained for a long time, and an organic EL display device having a long product life can be realized.

  Moreover, according to this structure, since it is not necessary to make a metal layer into a multilayer structure, the light transmittance of a relatively high metal layer is realizable. Therefore, it is possible to realize high light emission extraction efficiency of the organic layer.

  In the organic EL display device according to the present invention, the metal layer includes at least one metal selected from Ni, Os, Pt, Pd, Al, Au, and Rh, and Mg, Ca, Sr, and Ba. , Li, Na, K, Rb, Cs, Ce, and Pr may be made of an alloy with one or more metals selected from the group consisting of.

  Mg, Ca, Sr, Ba, Li, Na, K, Rb, Cs, Ce and Pr (hereinafter, “Mg, Ca, Sr, Ba, Li, Na, K, Rb, Cs, Ce and Pr” are changed to “Mg. Etc. ”) may have a low work function and achieve high electron injection efficiency. Therefore, according to this configuration, it is possible to realize an organic EL display device with high luminous efficiency of the organic layer and high luminance.

  Ni, Os, Pt, Pd, Al, Au, and Rh (hereinafter, “Ni, Os, Pt, Pd, Al, Au, and Rh” may be abbreviated as “Ni etc.”) are not easily oxidized. Therefore, Mg or the like that is easily oxidized can be effectively shielded from oxygen. Therefore, in this configuration, oxidation of Mg or the like is suppressed, high electron injection efficiency into the organic layer can be maintained for a long time, and an organic EL display device with a long product life can be realized.

  Moreover, since Ni etc. are electroconductive, the ohmic property (contact resistance) of a metal layer and a transparent electrode layer is favorable. Therefore, according to this structure, the 2nd electrode with high electron injection efficiency to an organic layer is realizable.

  Further, since Ni or the like has good coverage with respect to the organic layer, formation of the metal layer is easy, and formation of pinholes or the like in the metal layer can be suppressed.

In the organic EL display device according to the present invention, the metal layer is formed in a stacked structure of a first metal layer in contact with the transparent electrode layer and a second metal layer in contact with the organic layer.
The first metal layer is made of one or more metals having a work function of 3.5 eV or more,
The second metal layer may be made of one or more metals having a work function of less than 3.5 eV.

  According to this configuration, since the second metal layer made of a low work function metal having a metal layer of less than 3.5 eV is in contact with the organic layer, the electron injection efficiency into the organic layer is high. Therefore, according to this configuration, it is possible to realize an organic EL display device with high luminous efficiency of the organic layer and high luminance.

  In this configuration, since the second metal layer made of a low work function metal that is easily oxidized is covered with the first metal layer made of a high work function metal that is difficult to be oxidized, the second metal layer is effectively shielded from oxygen. be able to. Therefore, in this structure, the oxidation of the low work function metal which comprises a 2nd metal layer is suppressed. Therefore, high electron injection efficiency into the organic layer can be maintained for a long time, and an organic EL display device having a long product life can be realized.

In the organic EL display device according to the present invention, the metal layer is formed in a stacked structure of a first metal layer in contact with the transparent electrode layer and a second metal layer in contact with the organic layer.
The first metal layer is made of one or more metals selected from Ni, Os, Pt, Pd, Al, Au, and Rh.
The second metal layer may be made of one or more metals selected from Mg, Ca, Sr, Ba, Li, Na, K, Rb, Cs, Ce, and Pr.

  According to this configuration, since the second metal layer made of Mg or the like having a low work function is in contact with the organic layer, the electron injection efficiency into the organic layer is high. Therefore, according to this configuration, it is possible to realize an organic EL display device with high luminous efficiency of the organic layer and high luminance.

  In this configuration, since the second metal layer made of Mg or the like that is easily oxidized is covered with the first metal layer made of Ni or the like that is not easily oxidized, the second metal layer can be effectively shielded from oxygen. . Therefore, in this configuration, oxidation of Mg constituting the second metal layer is suppressed, high electron injection efficiency into the organic layer can be maintained for a long time, and an organic EL display device having a long product life is realized. Can do.

  In addition, since Ni or the like has good coverage with respect to the second metal layer made of Mg or the like, it is easy to form the first metal layer, and pinholes and the like are formed in the metal layer. Can be suppressed.

  Further, the organic EL display device according to the present invention may have an arithmetic average roughness defined by JIS B 0601-1994 on the observer side surface of the transparent electrode layer of 1 nm or more and 30 nm or less. .

  According to this configuration, the observer-side surface of the transparent electrode layer (hereinafter sometimes abbreviated as “observer-side surface”) acts as a thin layer having intermediate optical characteristics between the transparent electrode layer and the outside air. The refractive index of the light emitted from the light emitting layer on the observer side surface changes gently. Therefore, it is possible to suppress the interface reflection that occurs on the observer side surface. Therefore, with this configuration, high extraction efficiency of light emission from the organic layer can be obtained, and an organic EL display device with higher luminance can be realized.

  In the organic EL display device according to the present invention, the light emitting layer may include a polymer light emitting material.

  When the light emitting layer contains a polymer light emitting material, the RGB light emitting layer pattern can be formed by a wet process such as an ink jet method, so that the RGB light emitting layer pattern can be formed with high accuracy and a large size An organic EL display device can also be supported.

  In the organic EL display device according to the present invention, the substrate may be an active matrix substrate having TFTs.

  According to this configuration, in principle, there is no restriction on the number of scanning electrodes, and a display close to static drive with a duty ratio of 100% can be achieved. Therefore, high-quality and large-capacity display with good panel brightness and response can be realized. it can.

  As described above, according to the present invention, since the emission of the organic layer can be prevented from being reflected at the interface between the contact surface of the metal layer and the transparent electrode layer, the emission efficiency of the emission of the organic layer is high. In addition, since a top emission method that extracts light from the organic layer without passing through a substrate on which a circuit that does not transmit light, such as TFTs, is formed, a higher luminance organic EL display device can be realized. it can.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view of a top emission type organic EL display device 1 according to an embodiment of the present invention.

  The organic EL display device 1 includes a substrate 10, an organic layer 30 provided on the substrate 10, and a first electrode 20 and a second electrode 40 provided so as to sandwich the organic layer 30.

  The substrate 10 has a function of supporting the organic EL display device 1 and is made of a substrate such as glass or plastic.

  Of course, the substrate 10 may be an active matrix substrate having TFTs. When the substrate 10 is an active matrix substrate, it is possible to realize the organic EL display device 1 capable of high-quality and large-capacity display with good panel luminance and response.

  The first electrode 20 is made of, for example, a metal having a high work function such as Au, Ni, Pt, etc., and has a function of injecting holes into the organic layer 30 and light emitted from the organic layer 30 to the first electrode 20 side. In the second electrode 40 side.

  The first electrode 20 is not limited to a single layer structure. For example, the first electrode 20 is made of a conductive material such as Ag or Al and has a high light reflectivity, and ITO or IZO (indium) having a high work function. Of course, it may be formed in a multilayer structure with a layer made of zinc oxide) or the like.

Further, an oxide layer having a layer thickness (for example, about 1 mm) that does not greatly hinder the conductivity between the first electrode 20 and the organic layer 30 may be provided between the first electrode 20 and the organic layer 30. Absent. For example, the coverage of the organic layer 30 can be further improved by providing a SiO ₂ layer or the like as the oxide layer.

  The organic layer 30 includes a hole injection layer 31, a light emitting layer 32, and an electron transport layer 33. However, the present invention is not limited to this configuration. That is, in the present invention, the organic layer 30 may have a single-layer structure including only the light emitting layer 32. In addition, the organic layer 30 may be configured by one or more of the hole injection layer 31, the hole transport layer, and the electron transport layer 33 and the light emitting layer 32.

  The hole injection layer 31 is not limited as long as the hole injection efficiency is good. Examples of the material for the hole injection layer 31 include a porphyrin compound, N, N′-bis- (3-methylphenyl) -N, N′-bis- (phenyl) -benzidine (TPD), N, N′-di (naphthalene). -1-yl) -N, N'-diphenyl-benzidine (NPD) and other aromatic tertiary amine compounds, hydrazone compounds, quinacridone compounds, styrylamine compounds and other low molecular materials, polyaniline, 3,4-polyethylenedioxy Polymer materials such as thiophene / polystyrene sulfonate (PEDT / PSS), poly (triphenylamine derivatives), polyvinylcarbazole (PVCz), poly (P-phenylene vinylene) precursor, poly (P-naphthalene vinylene) precursor And high molecular material precursors.

  The hole injection layer 31 is not limited to a single layer structure, and may of course have a multilayer structure.

  The hole injection layer 31 can be formed by a known wet process such as a spin coating method.

  The light emitting layer 32 may include a low molecular light emitting material or a polymer light emitting material. In the case of the light emitting layer 32 containing a low molecular light emitting material, it can be formed by a method such as vacuum deposition. On the other hand, the light emitting layer 32 containing a polymer light emitting material is more preferable because it can be formed by a wet process, and the organic EL display device 1 having a high-definition and large-area substrate 10 can be easily manufactured. .

  Specifically, using an organic light emitting layer forming paint, spin coating method, ink jet method, relief printing method, intaglio printing method, screen printing method, spray coating method, doctor blade method, discharge coating method, micro gravure coating method The light emitting layer 32 containing the polymer light emitting material can be formed by a wet process such as the above. The organic light-emitting layer-forming paint is a solution in which at least one light-emitting material is dissolved in a solvent. In addition to the light-emitting material, a leveling agent, a light-emission assist agent, an additive (donor, acceptor, etc.), electric transport It may contain an agent, a luminescent dopant, and the like.

  As a luminescent material, the well-known luminescent material for organic LED elements can be used. Such light emitting materials are classified into polymer light emitting materials, precursors of polymer light emitting materials, and the like. Although these specific compounds are illustrated below, this invention is not limited to these.

  Examples of the polymer light emitting material include poly (2-decyloxy-1,4-phenylene) (DO-PPP), poly [2,5-bis- [2- (N, N, N-triethylammonium) ethoxy]- 1,4-phenyl-alto 1,4-phenylylene] dibromide (PPP-NEt3 +), poly [2- (2′-ethylhexyloxy) -5-methoxy-1,4-phenylenevinylene] (MEH-PPV), etc. Is mentioned.

  Examples of the precursor of the polymer light emitting material include a poly (P-phenylene vinylene) precursor (Pre-PPV), a poly (P-naphthalene vinylene) precursor (Pre-PNV), and the like.

  The solvent is not limited as long as it can dissolve or disperse the light emitting material, and examples thereof include pure water, methanol, ethanol, THF (tetrahydrofuran), chloroform, toluene, xylene, and trimethylbenzene.

  The electron transport layer 33 has a function of improving the transport efficiency of electrons injected from the second electrode 40 into the light emitting layer 32. Further, the electron transport layer 33 can be formed of a solution containing an electron transport material by a known wet process such as a spin coating method.

  A known electron transport material can be used as the electron transport material. For example, low molecular weight materials such as oxadiazole derivatives, triazole derivatives, benzoquinone derivatives, naphthoquinone derivatives, and fluorenone derivatives, and polymer materials such as poly [oxadiazole] are exemplified.

  The electron transport layer 33 is not limited to a single layer structure, and may of course have a multilayer structure.

  The second electrode 40 includes a transparent electrode layer 42 and a metal layer 41.

  On the contact surface 43 of the metal layer 41 with the transparent electrode layer 42, an uneven shape having Ra of 1/5 or more and 1/2 or less of the maximum layer thickness of the metal layer 41 is formed (note that the metal layer 41 The maximum layer thickness means the shortest distance between the highest peak portion of the contact surface 43 with the transparent electrode layer 42 on which the concavo-convex shape is formed and the bottom surface of the metal layer 41. Hereinafter, the same applies in this specification. ).

  According to this configuration, the contact surface 43 acts as a thin layer having intermediate optical characteristics between the metal layer 41 and the transparent electrode layer 42, and the refractive index of the light emitted from the light emitting layer 32 at the contact surface 43 is It changes slowly. Therefore, interface reflection by the contact surface 43 of the light emitted from the light emitting layer 32 can be suppressed. Therefore, high extraction efficiency of light emission from the light emitting layer 32 can be realized, and the organic EL display device 1 with high luminance can be realized.

  When the ratio of Ra of the contact surface 43 to the maximum layer thickness of the metal layer 42 (hereinafter sometimes referred to as “Ra ratio”) is less than 1/5, the uneven shape of the contact surface 43 is small. In addition, a sufficient interface reflection suppressing effect cannot be obtained. On the other hand, when the Ra ratio is greater than 1/2, the layer thickness of the metal layer 42 becomes non-uniform, and the layer thickness of a part of the metal layer 42 becomes extremely thin relative to the layer thickness of the other part. Further, the portion of the metal layer 42 that is extremely thin has low electron injection efficiency into the organic layer 30. Therefore, the electron injection efficiency into the organic layer 30 as the whole metal layer 42 is lowered. Therefore, high luminous efficiency of the organic layer 30 cannot be obtained. Furthermore, in this case, since the light emitted from the organic layer 30 is scattered by the contact surface 43, the front luminance is reduced. Therefore, when the Ra ratio is larger than ½, the organic EL display device 1 with high luminance cannot be realized.

  The metal layer 41 having various Ra contact surfaces 43 is obtained, for example, by a resistance heating vapor deposition method. Although it can form by selecting suitably, it is not limited to this method at all.

  The metal layer 41 has a maximum layer thickness of 1 nm or more and 20 nm or less.

  When the maximum layer thickness of the metal layer 41 is less than 1 nm, the efficiency of electron injection into the organic layer 30 is low, and the organic EL display device 1 having a desired luminance cannot be realized.

  Further, when the maximum layer thickness of the metal layer 41 is larger than 20 nm, the light transmittance of the metal layer 41 is extremely lowered, the light extraction efficiency of the organic layer 30 is lowered, and an organic EL display device having a desired luminance is obtained. 1 cannot be realized.

  When the maximum layer thickness of the metal layer 41 is 1 nm or more and 20 nm or less, the metal layer 41 has both high light transmittance and electron injection efficiency, and the high emission efficiency of the organic layer 30 and the organic layer 30 Both the light emission extraction efficiency can be realized. Therefore, the organic EL display device 1 with high luminance can be realized.

  The metal layer 41 is hardly oxidized with a metal layer made of an alloy of one or more kinds of low work function metals and one or more kinds of high work function metals that are hardly oxidized, or a metal layer made of one or more kinds of low work function metals. A multilayer structure with a metal layer made of a high work function metal can be used. According to this configuration, since the metal layer 41 contains a low work function metal, high electron injection efficiency into the organic layer 30 can be realized. Therefore, according to this configuration, the organic EL display device 1 with high luminous efficiency of the organic layer 30 and high luminance can be realized.

  The low work function metal generally has a property of being easily oxidized, and when the low work function metal is oxidized, the electron injection efficiency of the metal layer 41 into the organic layer 30 is lowered. On the other hand, a high work function metal generally has a property of being hardly oxidized. According to this configuration, the low work function metal can be shielded from oxygen by the high work function metal. Therefore, in this configuration, oxidation of the low work function metal is suppressed, high electron injection efficiency into the organic layer 30 can be maintained for a long time, and the organic EL display device 1 having a long product life can be realized.

  Examples of the low work function metal include Mg, Ca, Sr, Ba, Li, Na, K, Rb, Cs, Ce, and Pr, but are not limited thereto. When the organic layer 30 includes a polymer light emitting material, Ca, Ba, and the like are particularly suitable.

  Examples of the high work function metal include, but are not limited to, Ni, Os, Pt, Pd, Al, Au, and Rh.

  Further, since Ni, Os, Pt, Pd, Al, Au, and Rh are conductive, the ohmic property (contact resistance) between the metal layer 41 and the transparent electrode layer 42 is good. Therefore, according to this structure, the 2nd electrode with high electron injection efficiency to the organic layer 30 is realizable.

  Moreover, since Ni, Os, Pt, Pd, Al, Au, and Rh have good coverage with respect to the organic layer 30, it is easy to form the metal layer 41, and the metal layer 41 has pinholes or the like. Formation can be suppressed.

  From the viewpoint of the electrical conductivity of the second electrode 40, the high work function metal is preferably a conductive metal. However, since the metal layer 40 is relatively thin, the high work function metal is not limited to the conductive metal.

The transparent electrode layer 42 has a function of improving the conductivity of the second electrode 40. The material used for the transparent electrode layer 42 is not particularly limited as long as it has high light transmittance and conductivity. Examples thereof include materials such as ITO, IZO, SnO ₂ , and ZnO.

  The transparent electrode layer 42 is formed such that Ra on the observer side surface 44 is 1 nm or more and 30 nm or less. According to this configuration, the observer-side surface 44 acts as a thin layer having intermediate optical characteristics between the transparent electrode layer 42 and the outside air, and the light emitted from the light-emitting layer 32 on the observer-side surface 44 is refracted. The rate changes slowly. Therefore, it is possible to suppress the light emitted from the light emitting layer 32 from being reflected on the viewer side surface 44 by the interface. Therefore, it is possible to realize the organic EL display device 1 with high emission efficiency of light emission from the light emitting layer 32 and high luminance.

  When the Ra of the observer side surface 44 is 1 nm or less, the unevenness shape of the observer side surface 44 is small, so that a sufficient interface reflection suppressing effect cannot be obtained. Moreover, when Ra of the observer side surface 44 is 30 nm or more, light emitted from the organic layer 30 is scattered by the observer side surface 44 and the front luminance of the organic EL display device 1 is lowered. Therefore, the high-brightness organic EL display device 1 cannot be realized.

  The transparent electrode layer 42 having various Ra observer-side surfaces 44 includes, for example, a resistance heating vapor deposition method, a current value flowing through a vapor deposition source made of the material of the transparent electrode layer 42, and a distance from the vapor deposition source to the substrate 10. However, the method is not limited to this method.

  Example 1 First, a first electrode is formed by depositing a Pt electrode having a layer thickness of 150 nm on a 5 cm square insulating substrate in a stripe shape having a width of 2 mm and a length of 5 cm by an electron beam evaporation method. did.

  Next, a mixed aqueous solution of polyethylene dioxythiophene (PEDOT) and polystyrene sulfonic acid (PSS) is applied by spin coating on the substrate on which the first electrode is formed, and dried at 150 ° C. for 20 minutes to thereby obtain a layer thickness of 60 nm. The hole injection layer was formed. The layer thickness of the hole injection layer was adjusted by controlling the concentration of the aqueous solution and the rotation speed during spin coating.

  Next, a solution of a polyolefin derivative was applied by spin coating on the substrate on which the hole injection layer was formed, and a light emitting layer was formed to form an organic layer.

  Next, Al containing 5% by weight of Ca in a stripe pattern orthogonal to the stripe pattern of the first electrode layer is formed on the substrate on which the organic layer has been formed by a resistance heating vapor deposition method so that the maximum layer thickness becomes 10 nm. As a result, a metal layer was formed. When the metal layer is formed, by appropriately adjusting the current value flowing through the Al vapor deposition source containing 5% by weight of Ca and the distance between the vapor deposition source and the substrate, the contact surface of the metal layer with the transparent electrode layer ( Hereinafter, various irregularities of Ra were formed on the contact surface.

Next, an organic EL layer is formed by forming a transparent electrode layer having a layer thickness of 100 nm on the substrate on which the metal layer is formed by DC sputtering using a DC sputtering method so that the stripe pattern is the same as the stripe pattern of the previously formed metal layer. A display device was created. For forming the IZO layer, an IZO sintered target was used as a target, and a mixed gas of Ar and O ₂ was used as a sputtering gas. Further, the substrate is not particularly heated during the formation of the metal layer and the transparent electrode layer.

  By the above method, organic EL display devices (samples 1 to 3) on which various Ra contact surfaces were formed were formed as Example 1.

  Table 1 shows the Ra and Ra ratio of the contact surfaces of Samples 1 to 3 and the normalized current efficiency.

  Ra was calculated from the result of observing the metal layer with an atomic force microscope (hereinafter sometimes abbreviated as “AFM”) after the metal layer was formed. FIG. 2A shows an AFM observation image of Sample 2 as an example of the observation image of the metal layer by AFM.

The current efficiency (unit: cd / A) is the light emission luminance (unit: cd / cm ² ) of the organic EL display device measured using a luminance meter and the current flowing through the organic EL display device at the time of luminance measurement. It was calculated from the value (unit: A) and the light emitting area (unit: m ² ) of the organic EL display device. Moreover, the normalized current efficiency shown in Table 1 is normalized by the value of Sample 2 that showed the highest current efficiency.

  (Example 2) In the same manner as in Example 1, for organic EL display devices having a maximum metal layer thickness of 1 mm and 20 mm, organic EL display device samples each having various Ra contact surfaces were formed. Prepared as Example 2. Further, Ra and current efficiency were calculated by the same method as shown in Example 1. The current efficiency was normalized by the current efficiency of the sample showing the highest current efficiency among the samples of Example 2.

  The graph shown in FIG. 3 shows the relationship between the Ra ratio of the organic EL display device according to Example 2 and the current efficiency.

  (Example 3) A Ca layer having a maximum layer thickness of 5 nm was formed on a substrate on which an organic layer was formed by resistance wire heating vapor deposition, and an Al layer having a maximum layer thickness of 10 nm was further formed thereon by resistance wire heating vapor deposition. A metal layer was formed by forming a film. Various Ra contact surfaces were formed on the metal layer by appropriately adjusting the value of the current flowing through the Ca vapor deposition source and the Al vapor deposition source and the distance between each vapor deposition source and the substrate. Other than that, Samples 4 to 6 were prepared in the same manner as in Example 1, and Example 3 was obtained. Further, Ra and current efficiency were calculated by the same method as shown in Example 1. The current efficiency was normalized by the current efficiency of Sample 5 that showed the highest current efficiency among the samples of Example 3.

  Table 2 shows the Ra, Ra ratio, and normalized current efficiency of the contact surfaces of Samples 4-6. The normalized current efficiency shown in Table 2 is normalized by the value of Sample 5 that showed the highest current efficiency.

Example 4 A transparent electrode layer was formed by depositing an ITO layer on a substrate on which a metal layer was formed by DC sputtering so as to have a stripe pattern similar to that of the metal layer. In forming the ITO layer, an ITO sintered target was used as a target, and a mixed gas of Ar and O ₂ was used as a sputtering gas. In addition, when the ITO layer was formed, various observer-side surfaces of Ra were formed on the transparent electrode layer by appropriately adjusting the sputtering input power and the film forming pressure. Except that, Samples 7 to 9 were prepared in the same manner as in Example 3, and designated as Example 4. Further, Ra and current efficiency were calculated by the same method as shown in Example 1.

  Table 3 shows the Ra on the viewer side surface of Samples 7 to 9 and the normalized current efficiency. The normalized current efficiency shown in Table 3 was normalized with the current efficiency of Sample 8 that showed the highest current efficiency among the samples of Example 4.

  (Example 5) FIG. 4 is a cross-sectional view of an organic EL display device 100 (sample 10) according to Example 5. As shown in FIG.

  The organic EL display device 100 includes a TFT substrate 110, an organic layer 130 provided on the TFT substrate 110, a first electrode 120 and a second electrode 140 provided so as to sandwich the organic layer 130, an organic An insulating film 124 is provided between the layer 130 and the first electrode 120.

  The TFT substrate 110 includes an insulating substrate 111, a source wiring 112, a gate wiring 113, a TFT 114, and a planarization film 115.

  The TFTs 114 are connected to each other by the source wiring 112 and the gate wiring 113.

  The TFT 114 covers the gate metal 116, the gate insulating film 117 provided on the gate metal 116, the island-shaped semiconductor 118 insulated from the gate metal 116 by the gate insulating film 117, and the peripheral portion of the island-shaped semiconductor 118. And a TFT electrode 119 formed in a hollow shape.

  The planarization film 115 is formed on the insulating substrate 111 so as to cover the source wiring 112, the gate wiring 113, and the TFT 114.

  The first electrode 120 is connected to the TFT electrode 119 through a through hole 123 provided in the planarizing film 115.

  The organic layer 130 includes a hole injection layer 131 and a light emitting layer 132.

  The second electrode 140 includes a metal layer 141 and a transparent electrode layer 142.

  Hereinafter, the manufacturing method of the organic EL display device 100 according to the fifth embodiment will be described with reference to FIGS.

  First, the TFT substrate 110 was formed on the insulating substrate 111 by forming the gate electrode 112, the gate wiring 113, the TFT 114, and the planarizing film 115 by a known film forming technique.

  Next, a Ni layer having a thickness of 150 nm was formed on the planarizing film 115 and inside the through hole 123 provided in the planarizing film 115 so as to be connected to the TFT electrode 119. Next, the first electrode 120 was formed by patterning the Ni layer in a matrix using a photolithographic technique.

Next, an insulating layer 124 made of SiO ₂ was formed so as to cover the upper portion of the through hole 123 and the edge portion of the first electrode 120.

  Next, the hole injection layer 131 and the light emitting layer 132 were formed on the first electrode 120 by using the same material and method as in Example 1 to form the organic layer 130.

  Next, a second electrode 140 is formed by forming a metal layer 141 and a transparent electrode layer 142 on the organic layer 130 by using the same material and method as in Example 1 to form an organic EL. A display device 100 was manufactured.

  Further, Ra and current efficiency were calculated by the same method as shown in Example 1.

  Table 4 shows the Ra and Ra ratio of the contact surface of the sample 10 according to Example 5 and the normalized current efficiency. The normalized current efficiency shown in Table 4 is obtained by normalizing the current efficiency of the sample 10 and the later-described sample 17 with the current efficiency of the sample 10.

  (Comparative Example 1) Organic EL display device samples 11 and 12 having contact surfaces with Ra of 1.2 nm and 5.7 nm, respectively, were prepared by the same materials and methods as in Example 1. Further, Ra and current efficiency were calculated by the same method as that of Example 1.

  Table 1 shows Ra and Ra ratio of the contact surfaces of Samples 11 and 12, and normalized current efficiency. The normalized current efficiency is normalized by the value of sample 2.

  FIG. 2B is an observation image by AFM of the contact surface of the sample 11 according to Comparative Example 1.

  (Comparative Example 2) By using the same materials and methods as in Example 2, for organic EL display devices having maximum metal layer thicknesses of 0.5 nm and 25 nm, organic EL displays having various Ra contact surfaces formed respectively. A display device sample was prepared and used as Comparative Example 2. Further, Ra and current efficiency were calculated by the same method as that of Example 1.

  The current efficiency was normalized by the current efficiency of the sample showing the highest current efficiency among the samples of Example 2.

  The graph shown in FIG. 3 shows the relationship between the Ra ratio of the organic EL display device in which the maximum thickness of the metal layer is 0.5 mm and 25 mm, respectively, and the current efficiency.

  (Comparative Example 3) Organic EL display device samples 13 and 14 having Ra of the contact surface of 2.7 nm and 8.5 nm, respectively, were prepared by the same material and method as in Example 3. Further, Ra and current efficiency were calculated by the same method as that of Example 1.

  Table 2 shows the Ra and Ra ratio of the contact surfaces of Samples 13 and 14 and the normalized current efficiency. The normalized current efficiency is normalized by the value of sample 5.

  (Comparative Example 4) Organic EL display device samples 15 and 16 having Ra on the viewer side surface of 0.8 nm and 33.8 nm, respectively, were prepared using the same materials and methods as in Example 4. Further, Ra and current efficiency were calculated by the same method as that of Example 1.

  Table 3 shows the Ra on the viewer side surface of Samples 14 and 15, the Ra ratio on the viewer side surface, and the normalized current efficiency. The normalized current efficiency is normalized by the value of sample 8.

  (Comparative Example 5) An organic EL display device sample 17 in which Ra on the contact surface of the metal layer was 1.6 nm was prepared by the same material and method as in Example 5. Note that Ra and current efficiency were calculated by the same method as in Example 1.

  Further, the current efficiency was calculated by the same method as shown in Example 1.

  Table 4 shows the Ra and Ra ratio of the contact surface of the sample 17 according to Comparative Example 5 and the normalized current efficiency. The normalized current efficiency shown in Table 4 is normalized with the value of sample 10.

  Table 1 shows Ra, Ra ratio (Ra of contact surface / maximum layer thickness of metal layer), and normalization of Samples 1 to 3 according to Example 1 and Samples 11 and 12 according to Comparative Example 1. It is a table | surface which showed the current efficiency made.

  From Table 1, when the Ra ratio is 1/5 or more and 1/2 or less as in Samples 1 to 3, a high current efficiency of 0.9 or more is shown, while the Ra ratio as in Samples 11 and 12 is shown. When is less than 1/5 or greater than 1/2, it can be seen that the current efficiency is less than 0.7.

  Since Samples 1 to 3 of Example 1 are formed so that the Ra ratio is 1/5 or more and 1/2 or less, the contact surface is a thin layer having intermediate optical characteristics between the metal layer and the transparent electrode layer. The refractive index of the light emitted from the light emitting layer at the contact surface changes gently. Therefore, interface reflection by the contact surface of the light emitted from the light emitting layer is suppressed. Therefore, it is considered that Samples 1 to 3 of Example 1 can realize high extraction efficiency of light emission from the light emitting layer and show high current efficiency.

  On the other hand, in the sample 11 of Comparative Example 1, since the Ra ratio is less than 1/5, the contact surface does not sufficiently function as a thin layer having intermediate optical characteristics between the metal layer and the transparent electrode layer. . Therefore, the interface reflection by the contact surface of the light emitted from the light emitting layer is not sufficiently suppressed. Therefore, in Sample 11, it is considered that high extraction efficiency of light emission from a desired light emitting layer was not obtained, and low current efficiency was exhibited.

  Moreover, in the sample 12 of the comparative example 1, since the Ra ratio is formed to be greater than 1/2, the metal layer has a non-uniform layer thickness, and a part of the metal layer is extremely thin. Moreover, the extremely thin portion of the metal layer does not have sufficient electron injection efficiency into the organic layer. Therefore, the electron injection efficiency into the organic layer is reduced as the whole metal layer. Therefore, high luminous efficiency of the organic layer cannot be obtained. In this case, light is irregularly reflected by the contact surface, and the front luminance is reduced. Therefore, sample 12 is considered to exhibit low current efficiency.

  FIG. 3 shows an organic EL display device in which the maximum layer thickness of the metal layer according to Example 2 is 1 mm and 20 mm, respectively, and an organic EL display in which the maximum layer thickness of the metal layer according to Comparative Example 2 is 0.5 mm and 25 mm, respectively. It is the graph which showed the relationship between the Ra ratio of a display apparatus, and the normalized current efficiency.

  From FIG. 3, it can be seen that high current efficiency is exhibited when the Ra ratio is 1/5 or more and 1/2 or less, regardless of the maximum thickness of the metal layer. The reason for this is as described for Table 1.

  In addition, as shown in FIG. 3, all the organic EL display devices in which the maximum layer thicknesses of the metal layers according to Example 2 are 1 mm and 20 mm, respectively, are 0.7 or more within a range where Ra ratio is 1/5 or more and 1/2 or less. On the other hand, it can be seen that the organic EL display device in which the maximum layer thickness of the metal layer according to Comparative Example 2 is 0.5 mm and 25 mm, respectively, shows a low current efficiency of less than 0.6.

  In the sample of Example 2, the maximum thickness of the metal layer is 1 nm or more and 20 nm or less. Therefore, the metal layer has a high electron injection efficiency into the organic layer, and a high light emission efficiency of the organic layer can be realized. In addition, the metal layer is considered to exhibit high current efficiency because it has good light transmittance and can realize high extraction efficiency of light emission from the organic layer.

  On the other hand, the sample having the maximum metal layer thickness of 0.5 nm in Comparative Example 2 has a low metal layer thickness and low electron injection efficiency, and therefore the organic layer has low light emission efficiency and low current efficiency. it is conceivable that.

  Further, in the sample of Comparative Example 2, the maximum thickness of the metal layer is 25 nm, because the metal layer is thick and the light transmittance of the metal layer is low, the organic layer has low light emission extraction efficiency and low current. It is considered to show efficiency.

  Note that the sample with the maximum metal layer thickness of 0.5 nm and the sample with 1 nm showed a tendency that the current efficiency decreased as the Ra ratio increased in the Ra ratio range of 1/5 to 1/2. . This is because the Ra ratio is increased and the current efficiency is improved by reducing the interface reflection at the contact surface, so that the Ra of the contact surface is increased, the thickness of the metal layer is reduced, and the electron injection efficiency is decreased. This is probably because the effect of decreasing the efficiency is greater.

  On the other hand, the sample with the maximum metal layer thickness of 20 nm and the sample with 25 nm showed a tendency that the current efficiency increased as the Ra ratio increased in the Ra ratio range of 1/5 to 1/2. This is because the maximum layer thickness of the metal layer is sufficiently larger than the Ra of the contact surface, so that the electron injection efficiency into the organic layer does not decrease due to the increase of the Ra ratio, and the contact surface increases due to the increase of the Ra ratio. This is probably because the effect of improving the current efficiency by reducing the interface reflection in the case is increased.

  Table 2 shows the Ra and Ra ratio of the contact surfaces between the samples 4 to 6 according to the example 3 and the samples 13 and 14 according to the comparative example 3, and the normalized current efficiency.

  As can be seen from the results shown in Table 2, the same results as in Example 1 and Comparative Example 1 were also obtained when the metal layer had a laminated structure of a Ca layer and an Al layer.

  That is, when the Ra ratio is 1/5 or more and 1/2 or less as in Samples 4 to 6, a high current efficiency of 0.8 or more is shown, while the Ra ratio is 1 as in Samples 13 and 14. When it was less than / 5 or greater than 1/2, it showed a low current efficiency of less than 0.7. The reason for this is as described for Table 1.

  Table 3 shows the Ra on the viewer side surface of Samples 7 to 9 according to Example 4 and Samples 15 and 16 according to Comparative Example 4, and the normalized current efficiency.

  As the results shown in Table 3, Samples 7 to 9 according to Example 4 in which the Ra on the observer side surface is 1 nm or more and 30 nm or less showed a high current efficiency of 0.9 or more. On the other hand, the sample 15 according to Comparative Example 4 in which the Ra on the observer side surface is less than 1 nm and the sample 16 according to Comparative Example 4 in which the Ra on the observer side surface is 30 nm or less have a low current efficiency of 0.8 or more. Indicated.

  In Samples 7 to 9 according to Example 4, Ra on the observer side surface is formed to be 1 nm or more and 30 nm or less, and therefore the observer side surface is intermediate between the outside air of the organic EL display device and the transparent electrode layer. The refractive index of light emitted from the light emitting layer on the observer side surface changes gently. Therefore, the interface reflection by the observer side surface of the light emitted from the light emitting layer is suppressed. Therefore, Samples 7 to 9 of Example 4 can realize high extraction efficiency of light emission from the light emitting layer, and are considered to exhibit high current efficiency.

  On the other hand, in the sample 15 of Comparative Example 4, since the Ra on the observer side surface is formed to be less than 1 nm, the observer side surface has intermediate optical characteristics between the outside air of the organic EL display device and the transparent electrode layer. As a thin layer, the interface reflection suppressing effect is not sufficient. Therefore, the interface reflection of the light emitted from the light emitting layer by the observer side surface is not sufficiently suppressed. Therefore, in Sample 15, it is considered that high extraction efficiency of light emission from a desired light emitting layer was not obtained, and low current efficiency was exhibited.

  Moreover, in the sample 16 of the comparative example 4, Ra on the surface on the viewer side is formed to be larger than 30 nm. Therefore, light emitted from the organic layer is scattered by the surface on the viewer side, and the front luminance is lowered. Therefore, it is considered that Sample 16 showed low current efficiency. In Sample 16, the white turbidity of the transparent electrode layer was confirmed by visual observation.

  Table 4 shows the Ra and Ra ratio of the contact surface between the sample 10 according to Example 5 and the sample 17 according to Comparative Example 5, and the normalized current efficiency.

  As shown in Table 4, also in the organic EL display device having the TFT substrate, the same results as those in Example 1 and Comparative Example 1 were shown.

  That is, when the Ra ratio is 1/5 or more and 1/2 or less as in the sample 10, high current efficiency is shown. On the other hand, when the Ra ratio is less than 1/5 as in the sample 17, the current is low. Showed efficiency. The reason for this is as described for Table 1.

1 is a cross-sectional view of a top emission type organic EL display device 1 according to an embodiment of the present invention. It is an observation image of the contact surface of the metal layer of sample 2 and sample 11 by AFM. An organic EL display device in which the maximum layer thickness of the metal layer according to Example 2 is 1 mm and 20 mm, respectively, and an organic EL display device in which the maximum layer thickness of the metal layer according to Comparative Example 2 is 0.5 mm and 25 mm, respectively. It is the graph which showed the relationship between Ra ratio and the normalized current efficiency. It is sectional drawing of the organic electroluminescent display apparatus 100 which concerns on Example 5 of this invention. It is sectional drawing of the conventional organic EL display apparatus of a bottom emission system. It is sectional drawing of the conventional organic EL display apparatus of a top emission system.

Explanation of symbols

1, 100, 200, 300 Organic EL display device 10, 201, 310 Substrate 20, 120, 202, 320 First electrode 30, 130, 203, 330 Organic layer 31, 131 Hole injection layer 32, 132 Light emitting layer 33 Electron transport Layers 40, 140, 204, 340 Second electrode 41, 141, 341 Metal layer 42, 142, 342 Transparent electrode layer 43, 343 Contact surface 44, 344 Observer side surface 110 TFT substrate 111 Insulating substrate 112 Source electrode 113 Gate wiring 114 TFT
115 planarization film 116 gate metal 117 gate insulating film 118 island-shaped semiconductor 119 TFT electrode 124 insulating film

Claims (10)

A substrate; a first electrode provided on the substrate; an organic layer including a light emitting layer provided on the first electrode; a light-transmitting metal layer provided on the organic layer; and a transparent electrode A top emission type organic electroluminescence display device comprising: a second electrode having a laminated structure with a layer; and taking out light emitted from the organic layer from the second electrode side,
The metal layer is an organic electroluminescence display device in which a contact surface with the transparent electrode layer is formed in an uneven shape. The organic electroluminescence display device according to claim 1,
The arithmetic mean roughness defined by JIS B 0601-1994 of the contact surface of the metal layer with the transparent electrode is an organic electroluminescence display having a thickness not less than 1/5 and not more than 1/2 of the maximum thickness of the metal layer. apparatus. The organic electroluminescence display device according to claim 1,
An organic electroluminescence display device wherein the maximum thickness of the metal layer is 1 nm or more and 20 nm or less. The organic electroluminescence display device according to claim 1,
An organic electroluminescence display device, wherein the metal layer is made of an alloy of one or more metals having a work function of 3.5 eV or more and one or more metals having a work function of less than 3.5 eV. The organic electroluminescence display device according to claim 1,
The metal layer includes at least one metal selected from Ni, Os, Pt, Pd, Al, Au, and Rh, and Mg, Ca, Sr, Ba, Li, Na, K, Rb, Cs, and Ce. And an organic electroluminescence display device made of an alloy of one or more metals selected from Pr. The organic electroluminescence display device according to claim 1,
The metal layer is formed in a laminated structure of a first metal layer in contact with the transparent electrode layer and a second metal layer in contact with the organic layer;
The first metal layer is made of one or more metals having a work function of 3.5 eV or more,
The second metal layer is an organic electroluminescence display device comprising one or more metals having a work function of less than 3.5 eV. The organic electroluminescence display device according to claim 1,
The metal layer is formed in a laminated structure of a first metal layer in contact with the transparent electrode layer and a second metal layer in contact with the organic layer;
The first metal layer is made of one or more metals selected from Ni, Os, Pt, Pd, Al, Au, and Rh.
The said 2nd metal layer is an organic electroluminescent display apparatus which consists of 1 or more types of metals chosen from Mg, Ca, Sr, Ba, Li, Na, K, Rb, Cs, Ce, and Pr. The organic electroluminescence display device according to claim 1,
An organic electroluminescence display device having an arithmetic average roughness defined by JIS B 0601-1994 of the observer-side surface of the transparent electrode layer of 1 nm or more and 30 nm or less. The organic electroluminescence display device according to claim 1,
An organic electroluminescence display device, wherein the light emitting layer includes a polymer light emitting material. The organic electroluminescence display device according to claim 1,
An organic electroluminescence display device, wherein the substrate is an active matrix substrate having TFTs.

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