Electrode substrate, display device, and method for manufacturing electrode substrate

Abstract

This electrode substrate comprises a substrate, an electrode disposed on the substrate, and a coating that covers a portion of the surface of the electrode. The electrode has a first metal atom. The coating includes a first coating having a second metal atom that has an ionization energy lower than that of the first metal atom.

Description

Electrode substrate, display device, method for manufacturing an electrode substrate

[0001] This disclosure relates to an electrode substrate, a display device equipped with the electrode substrate, and a method for manufacturing the electrode substrate.

[0002] Devices such as display devices equipped with light-emitting elements include an electrode substrate on which electrodes containing silver or the like are formed. Such electrode substrates have the problem of corrosion of the electrode surface due to contact with chemicals or the like on the electrodes. Patent Document 1 discloses a technique for forming a coating on the surface of silver or a silver alloy to prevent corrosion of the silver or silver alloy.

[0003] Japanese Patent Application Publication No. 2007-70656

[0004] Even when a coating is applied to the electrodes of an electrode substrate using the technology described in Patent Document 1, if defects such as pinholes occur in the coating, it is difficult to protect the surface of the electrodes exposed through these defects from corrosion. Thus, the technology described in Patent Document 1 may not be sufficient to reduce corrosion on the surface of the electrodes of the electrode substrate.

[0005] An electrode substrate according to one aspect of the present disclosure comprises a substrate, at least one electrode located on the substrate and having a first metal atom, and a coating covering at least one of the electrode's surface, a portion of the electrode's upper surface located on the side opposite to the substrate, and a portion of the electrode's side surface, wherein the coating includes a first coating in contact with the portion of the electrode's surface and having a second metal atom having a lower ionization energy than the first metal atom.

[0006] A method for manufacturing an electrode substrate according to one aspect of the present disclosure includes preparing a substrate, forming at least one electrode located on the substrate and having a first metal atom, and forming a coating that covers at least one of the electrode's surface, the electrode upper surface located on the side opposite to the substrate, and the electrode side surface, wherein the formation of the coating includes forming a first coating having a second metal atom having a lower ionization energy than the first metal atom.

[0007] According to one aspect of this disclosure, corrosion of the electrode surface of the electrode substrate is reduced.

[0008] This is a schematic side cross-sectional view of a display device according to Embodiment 1. This is a schematic diagram of a display device according to Embodiment 1. This is a flowchart of a method for manufacturing a display device according to Embodiment 1. This is a process cross-sectional view in the method for manufacturing a display device according to Embodiment 1. This is another a schematic enlarged view of a side cross-section of an electrode substrate and a hole injection material layer to show the mechanism for preventing electrode corrosion by the first coating according to Embodiment 1. This is a schematic side cross-sectional view of a display device according to Embodiment 2. This is a flowchart of a method for manufacturing a display device according to Embodiment 2. This is a process cross-sectional view in the method for manufacturing a display device according to Embodiment 2. This is a schematic side cross-sectional view of a display device and a schematic plan view of an electrode substrate according to Embodiment 3. This is a process cross-sectional view in the method for manufacturing a display device according to Embodiment 3. This is a schematic side cross-sectional view of a display device according to Embodiment 4. This is a flowchart of a method for manufacturing a display device according to Embodiment 4. This is a process cross-sectional view in the method for manufacturing a display device according to Embodiment 4. This is another process cross-sectional view in the method for manufacturing a display device according to Embodiment 4. This is a schematic enlarged view of a side cross-section of an electrode substrate and a hole injection material layer to show the mechanism for preventing corrosion of the first coating by the second coating according to Embodiment 4.

[0009] [Embodiment 1] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, similar components are denoted by the same reference numeral and their descriptions are omitted. Also, in this disclosure, for the sake of simplicity of illustration, the scale may differ in the drawings for components denoted by the same reference numeral, and different hatching may be applied. However, the components shown in each drawing of this disclosure are merely examples, and their scale is not limited to that shown in the drawing. Furthermore, even for components denoted by different hatching in this disclosure, components denoted by the same reference numeral have the same configuration as described above. In addition, in each drawing of this disclosure, if two components have substantially the same shape but different compositions, they may be denoted by different reference numerals but have the same hatching.

[0010] <Display Device: Overview> Figure 2 is a schematic diagram of the display device 1 according to this embodiment. The display device 1 is a device that can be used, for example, in a television or smartphone display. The display device 1 comprises a display unit DA including a plurality of subpixels and a driver circuit DR that drives the plurality of subpixels. Each of the plurality of subpixels comprises a light-emitting element, which will be described later, and a pixel circuit PC that drives the light-emitting element.

[0011] In particular, the display device 1 includes a red subpixel XR, a green subpixel XG, and a blue subpixel XB in the display unit DA. The red subpixel XR is equipped with a red light-emitting element 3R that emits red light, the green subpixel XG is equipped with a green light-emitting element 3G that emits green light, and the blue subpixel XB is equipped with a blue light-emitting element 3B that emits blue light, each as a light-emitting element.

[0012] The display device 1 performs display on the display unit DA by controlling the light emitted from each of the multiple light-emitting elements formed on the display unit DA via the driver circuit DR and the pixel circuit PC. In particular, the display device 1 may perform full-color display by controlling the red light from the red subpixel XR, the green light from the green subpixel XG, and the blue light from the blue subpixel XB, respectively.

[0013] The structure of the display unit DA of the display device 1 will be described in more detail with reference to Figure 1. Figure 1 is a schematic side cross-sectional view of the display device 1 according to this embodiment. All schematic side cross-sectional views of the display device 1 according to this disclosure, including Figure 1, show a cross-section perpendicular to the display surface of the display device 1 and passing through the red subpixel XR, the green subpixel XG, and the blue subpixel XB. In the schematic side cross-sectional views of the display device 1 according to this disclosure, including Figure 1, the planar direction DP parallel to the upper surface of the substrate 21 (described later) is defined as the left-right direction with respect to the plane of the paper, and the film thickness direction DT parallel to the thickness direction of the substrate 21 is defined as the up-down direction with respect to the plane of the paper.

[0014] <Electrode Substrate: Substrate and Electrodes> The display device 1 according to this embodiment includes an electrode substrate 2. The electrode substrate 2 includes a substrate 21 and at least one electrode 22 on the substrate 21. In particular, in this embodiment, the electrode substrate 2 has a plurality of island-shaped electrodes 22 at positions where the red subpixel XR, green subpixel XG, and blue subpixel XB overlap in a plan view of the substrate 21. For example, the electrodes 22 include electrodes 22R, 22G, and 22B at positions where they overlap with the red subpixel XR, green subpixel XG, and blue subpixel XB in a plan view of the substrate 21.

[0015] The substrate 21 may include a drive circuit (not shown) for each of the multiple electrodes 22, capable of individually driving each of the electrodes 22. The drive circuit of the substrate 21 may individually drive the electrodes 22 by applying a voltage to each electrode 22 through control by the driver circuit DR described above. A light-emitting layer 3, described later, on which multiple light-emitting elements are formed, is located on the substrate 21. Therefore, the drive circuit of the substrate 21 may individually drive each of the multiple light-emitting elements provided by the display device 1 to control the display by the display device 1.

[0016] The electrode 22 has a first metal atom. The first metal atom may be a metal atom with high light reflectivity, particularly a silver atom, from the viewpoint of improving the efficiency of light extraction from the light-emitting element described later.

[0017] <Electrode Substrate: Coating> The electrode substrate 2 is further provided with a coating 4. The coating 4 covers at least one of the electrode upper surface 22U located on the side opposite to the substrate 21 in the film thickness direction DT, and a portion of the electrode side surface 22S, which is the end face of the electrode 22 in the planar direction DP. In other words, the coating 4 covers a portion of the electrode surface 22, excluding the lower surface on the substrate 21 side. In particular, in this embodiment, the coating 4 covers at least one of the electrode upper surface 22U and the electrode side surface 22S of each of the multiple electrodes 22.

[0018] In particular, in this embodiment, the coating 4 includes a first coating 41 that is in contact with a part of the surface of the electrode 22. The first coating 41 includes a second metal atom whose ionization energy, which corresponds to the difference between the vacuum level and the Fermi level, is lower than that of the first metal atom present in the electrode 22. For example, if the first metal atom is a silver atom, the second metal atom may be an aluminum atom.

[0019] In this embodiment, the coating 4 covers a portion of the electrode top surface 22U of the electrode 22, but does not cover the electrode side surface 22S. In particular, in this embodiment, the coating 4 covers the entire electrode top surface 22U. Specifically, the first coating 41 may cover each of the electrode top surfaces 22U of multiple electrodes 22. For example, the first coating 41 may include a first coating 41R that covers the electrode top surface 22U of electrode 22R, a first coating 41G that covers the electrode top surface 22U of electrode 22G, and a first coating 41B that covers the electrode top surface 22U of electrode 22B.

[0020] The thickness of the first coating 41 in the thickness direction DT may be 50 nm or less, from the viewpoint of not hindering the reflection of light at the electrode 22 (described later) or reducing the influence on the driving of the light-emitting element (described later) through the driving of the electrode 22. Alternatively, the thickness of the first coating 41 in the thickness direction DT may be 1 nm or more, from the viewpoint of further reducing corrosion of the electrode 22 (described later).

[0021] <Light-emitting element layer: Overview> The display device 1 includes a light-emitting element layer 3 on a substrate 21. The light-emitting element layer 3 is comprised of an anode 31, a hole injection layer 32, a hole transport layer 33, a light-emitting layer 34, an electron transport layer 35, and a cathode 36, stacked in order from the substrate 21 side. In this embodiment, each layer of the light-emitting element layer 3 may be stacked along the film thickness direction DT. The film thickness of each layer of the light-emitting element layer 3 may also be a thickness along the film thickness direction DP.

[0022] Furthermore, the display device 1 includes a bank BK located on the substrate 21. The bank BK may contain an insulating material such as a resin material, or it may contain a light-transmitting resin material such as polyimide. The bank BK partitions at least the anode 31 and the light-emitting layer 34 of the light-emitting element layer 3 for each subpixel. For this reason, the anode 31 includes anode 31R, anode 31G, and anode 31B at positions that overlap with the red subpixel XR, green subpixel XG, and blue subpixel XB in a plan view of the substrate 21. The light-emitting layer 34 includes a red light-emitting layer 34R, a green light-emitting layer 34G, and a blue light-emitting layer 34B at positions that overlap with the red subpixel XR, green subpixel XG, and blue subpixel XB in a plan view of the substrate 21. On the other hand, the hole injection layer 32, hole transport layer 33, electron transport layer 35, and cathode 36 may be formed in common for multiple subpixels regardless of their position in a plan view of the substrate 21.

[0023] Therefore, the light-emitting element layer 3 comprises an anode 31R, a hole injection layer 32, a hole transport layer 33, a red light-emitting layer 34R, an electron transport layer 35, and a cathode 36 as a red light-emitting element 3R, which overlaps with the red subpixel XR in a plan view of the substrate 21. The light-emitting element layer 3 also comprises an anode 31G, a hole injection layer 32, a hole transport layer 33, a green light-emitting layer 34G, an electron transport layer 35, and a cathode 36 as a green light-emitting element 3G, which overlaps with the green subpixel XG in a plan view of the substrate 21. Furthermore, the light-emitting element layer 3 also comprises an anode 31B, a hole injection layer 32, a hole transport layer 33, a blue light-emitting layer 34B, an electron transport layer 35, and a cathode 36 as a blue light-emitting element 3B, which overlaps with the blue subpixel XB in a plan view of the substrate 21. Therefore, in this embodiment, bank BK partitions the spaces between the multiple light-emitting elements provided by the display device 1.

[0024] Therefore, each of the multiple light-emitting elements provided on the substrate 21 of the display device 1 comprises an anode 31, a cathode 36 facing the anode 31, and a light-emitting layer 34 between the anode 31 and the cathode 36.

[0025] <Relationship between the light-emitting element layer and the electrodes of the electrode substrate> In this embodiment, of the electrodes anode 31 and cathode 36 provided by the light-emitting element layer 3, the anode 31 located closer to the substrate 21 relative to the light-emitting layer 34 is composed of the electrodes 22 of the electrode substrate 2. In other words, each of the anodes 31 is each of the electrodes 22 of the electrode substrate 2. Specifically, anode 31R is electrode 22R, anode 31G is electrode 22G, and anode 31B is electrode 22B.

[0026] Furthermore, the hole injection layer 32 of the light-emitting layer 3 is formed on the coating 4 of the electrode substrate 2. Therefore, each of the multiple light-emitting elements in the display device 1 is located between the electrode 22 and the light-emitting layer 34 and has a hole injection layer 32 that is in contact with the coating 4 on the electrode 22.

[0027] However, the light-emitting element layer 3 may be arranged with respect to the substrate 21 in the reverse order from the order shown in Figure 1, with respect to each layer from the anode 31 to the cathode 36. For example, the light-emitting element layer 3 may be arranged by stacking the cathode 36, electron transport layer 35, light-emitting layer 34, hole transport layer 33, hole injection layer 32, and anode 31 in that order from the substrate 21 side. In this case, each of the cathodes 36 may be each of the electrodes 22 of the electrode substrate 2.

[0028] In this embodiment, the bank BK may cover a portion of the electrode upper surface 22U and the electrode side surface 22S of a plurality of electrodes 22. The coating 4 may also cover a portion of the electrode upper surface 22U that is exposed from the bank BK. In particular, the bank BK may be formed in a position that overlaps with the periphery of the electrode upper surface 22U of each electrode 22 in a plan view of the substrate 21, and the coating 4 may cover the region of the electrode upper surface 22U surrounded by the bank BK in a plan view of the substrate 21. However, in this embodiment, the coating 4 may cover a portion of the electrode upper surface 22U that is not exposed from the bank BK, and in particular, a portion of the coating 4 may be located between the electrode 22 and the bank BK.

[0029] <Light-emitting element: Anode and cathode> Of the anode 31 and cathode 36, the electrode located on the substrate 21 side of the light-emitting layer 34 is a reflective electrode having the first metal atom described above. For example, in this embodiment, the anode 31 is a reflective electrode having the first metal atom. The first metal atom of the anode 31 may be a silver atom, as described above, from the viewpoint of reflecting light from the light-emitting layer 34 and improving the efficiency of light extraction from each of the multiple light-emitting elements provided by the display device 1. However, as described above, the first metal atom is not particularly limited as long as its ionization energy is higher than that of the second metal atom of the first coating 41, and may be, for example, an aluminum atom, a copper atom, or a gold atom. The anode 31 may also have multiple metal atoms, including the first metal atom.

[0030] Of the anode 31 and cathode 36, the electrode located on the side opposite the substrate 21 from the light-emitting layer 34 is a transparent electrode that transmits visible light, including light from the light-emitting layer 34. For example, in this embodiment, the cathode 36 is a transparent electrode. Examples of transparent electrodes include ITO, InZnO, and SnO. ２ Alternatively, FTO (Free Trade Off) or similar terms may be used.

[0031] <Light-emitting element: Hole injection layer> The hole injection layer 32 is a layer that injects holes from the anode 31 into the light-emitting layer 34. The material of the hole injection layer 32 can be an organic or inorganic material with hole transport properties that has been conventionally used in light-emitting elements and the like. The hole injection layer 32 contains nickel oxide (NiO) nanoparticles: [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz), [2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl]phosphonic acid (Me-2PACz), [2-(3,6-dichloro-9H-carbazole-9-yl)ethyl]phosphonic acid (Cl-2PACz), and [2-(3,6-dibromo-9H-carbazole-9-yl)ethyl]phosphonic acid (Br-2PA It may also contain self-assembled monolayers such as Cz), [4-(9H-carbazole-9-yl)butyl]phosphonic acid (4PACz), [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACz), [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz), [4-(3,6-dichloro-9H-carbazole-9-yl)butyl]phosphonic acid (Cl-4PACz), and [4-(3,6-dibromo-9H-carbazole-9-yl)butyl]phosphonic acid (Br-4PACz). Other materials for the hole injection layer 32 include, for example, a composite of poly(3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonic acid (PSS) (abbreviated as "PEDOT:PSS"), CuSCN (copper thiocyanate), and molybdenum oxide (MoO2). ３ ), tungsten oxide (WO ３ ), vanadium oxide (V ２ O ５ ), cuprous oxide (Cu ２ Examples include 0) and cupric oxide (CuO). Furthermore, the hole implantation layer 32 may also contain bulk NiO (nickel oxide) as a material, rather than nanoparticles. These materials may be used individually or mixed in combination of two or more as appropriate.

[0032] <Light-emitting element: Hole transport layer> The hole transport layer 33 is a layer that transports holes injected from the anode 31 to the hole injection layer 32 to the light-emitting layer 34. The material of the hole transport layer 33 can be an organic or inorganic material with hole transport properties that has been conventionally used in light-emitting elements, etc. The hole transport layer 33 may include, for example, poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-4-sec-butylphenyl))diphenylamine)] (abbreviated as "TFB"), poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine] (abbreviated as "poly-TPD"), polyvinylcarbazole (abbreviated as "PVK"), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (abbreviated as "PTAA"), etc. Furthermore, the hole transport layer 33 may contain only one type of these materials, or it may contain a mixture or layering of two or more types as appropriate.

[0033] <Light-emitting element: Electron transport layer> The electron transport layer 35 is a layer that transports electrons injected from the cathode 36 to the light-emitting layer 34. The electron transport layer 35 in this embodiment may have nanoparticles as an electron transport material. The electron transport layer 35 may also contain ligands that can coordinate to the nanoparticles. For example, the nanoparticles may be zinc oxide (ZnO), zinc oxide (ZnO) doped with at least one of Li, Mg, Al, Ti, Ga, and Zr, titanium oxide (TiO) ２ ), or zirconium oxide (ZrO ２ ) may be nanoparticles. Note that in this disclosure, the chemical formulas are representative examples. Furthermore, in this disclosure, the composition ratios described in the chemical formulas do not necessarily have to be stoichiometric measurements that match the composition of the actual compound.

[0034] Note that the electron transport material included in the electron transport layer 35 is not limited to nanoparticles. For example, in the electron transport layer 35, as the electron transport material, in a light-emitting element including quantum dots, an organic or inorganic material having electron transport properties, which has been conventionally adopted, can be used. The electron transport material may include, for example, 2,2',2''-(1,3,5-benzenetriyl)-tris(1-phenyl-1H-benzimidazole) (abbreviation "TPBi"), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (abbreviation "BCP"), 4,7-diphenyl-1,10-phenanthroline (abbreviation "Bphen"), etc. Alternatively, the electron transport layer 35 may include, as the electron transport material, bulk zinc oxide (ZnO), zinc oxide (ZnO), titanium oxide (TiO ２ ), or zirconium oxide (ZrO ２ ). The bulk zinc oxide (ZnO) may be doped with at least one of Li, Mg, Al, Ti, Ga, and Zr. The electron transport material may include only one kind of the above-described materials, or may appropriately include two or more kinds.

[0035] <Light-emitting element: Light-emitting layer> The light-emitting layer 34 includes a light-emitting material that emits light by recombination of holes injected from the anode 31 through the hole injection layer 32 and the hole transport layer 33 and electrons injected from the cathode 36 through the electron transport layer 35. In particular, the red light-emitting layer 34R includes a red light-emitting material that emits red light, the green light-emitting layer 34G includes a green light-emitting material that emits green light, and the blue light-emitting layer 34B includes a blue light-emitting material that emits blue light.

[0036] The light-emitting material included in the light-emitting layer 34 may include various light-emitting materials including conventionally known light-emitting materials as long as the material emits light by recombination of holes and electrons. For example, the light-emitting material included in the light-emitting layer 34 may include an organic material including an organic fluorescent material or an organic phosphorescent material, etc. In this case, each of the plurality of light-emitting elements included in the display device 1 may be an OLED element, in other words, an organic EL element. Alternatively, the light-emitting material included in the light-emitting layer 34 may include a light-emitting semiconductor nanoparticle, in other words, a light-emitting quantum dot. In this case, each of the plurality of light-emitting elements included in the display device 1 may be a QLED element.

[0037] <Manufacturing Method of Display Device: Overview>The manufacturing method of the display device 1 according to this embodiment will be described with reference to FIGS. 3 to 6. FIG. 3 is a flowchart showing the manufacturing method of the display device 1 according to this embodiment. Each of FIGS. 4 to 6 is a process cross-sectional view in the manufacturing method of the display device 1 according to this embodiment. The process cross-sectional views in the present disclosure including each of FIGS. 4 to 6 all show the cross-sections at positions corresponding to the side cross-section of the display device 1 shown in FIG. 1.

[0038] <Manufacturing Method of Display Device: Formation of Electrode Substrate and Bank>In the manufacturing method of the display device 1 according to this embodiment, first, the substrate 21 shown in FIG. 4 is prepared (step S1). The substrate 21 may be prepared by forming a plurality of circuit boards on a base material. Also, in step S1, a large-sized substrate 21 may be prepared. In this case, in the manufacturing method of the display device 1, after the formation of the light-emitting element layer 3 described later on the substrate 21 is completed, the substrate 21 and the light-emitting element layer 3 may be divided to manufacture a plurality of display devices 1 at once.

[0039] Next, as shown in FIG. 4, an electrode layer 22L is formed on the substrate 21 (step S2). In particular, the electrode layer 22L has the first metal atom described above. The electrode layer 22L may be a metal thin film. The electrode layer 22L may be formed by various film formation methods including sputtering.

[0040] Next, as shown in FIG. 4, a first coating layer 41L is formed on the electrode layer 22L (step S3). In particular, the first coating layer 41L has the second metal atom described above. The first coating layer 41L may be a metal thin film. The first coating layer 41L may be formed by various film formation methods including sputtering.

[0041] Next, the electrode layer 22L and the first coating layer 41L are patterned (step S4). In step S4, for example, first, as shown in FIG. 5, a resist R1 is formed on the first coating layer 41L (step S4-1). The resist R1 may be, for example, a photoresist containing a photosensitive material. The formation of the resist R1 may be performed by various film formation methods including coating methods such as the slit coating method.

[0042] Next, as shown in Figure 5, the resist R1 is patterned (step S4-2). In step S4-2, for example, the resist R1 is patterned so that resist R1 remains only in the positions corresponding to each subpixel of the display device 1, in other words, in the portions where each electrode 22 of the electrode substrate 2 is located. The patterning of resist R1 may be performed by various methods such as photolithography. As a result, resist R2 remains only in the positions corresponding to each subpixel of the display device 1.

[0043] Next, the electrode layer 22L and the first coating layer 41L are etched from the resist R2 side rather than the substrate 21 (step S4-3). In step S4-3, the electrode layer 22L and the first coating layer 41L are etched together with the resist R2 from the side opposite to the substrate 21 by various etching methods, such as dry etching.

[0044] Here, the resist R2 is formed only on a portion of the substrate 21 in a plan view. Therefore, the portions of the electrode layer 22L and the first coating layer 41L located beneath the resist R2 are not etched, while the portions of the electrode layer 22L and the first coating layer 41L exposed from the resist R2 are etched. Upon completion of step S4-3, as shown in Figure 5, a portion of the electrode layer 22L and the first coating layer 41L remain on the substrate 21 only at positions corresponding to each subpixel of the display device 1. In this embodiment, after step S4-3, the remaining resist R2 may be removed by washing each part of the substrate 21 with an appropriate solvent.

[0045] As described above, electrodes 22 and the first coating 41 are formed at positions corresponding to each subpixel of the display device 1. In particular, in a plan view of the substrate 21, electrodes 22R and the first coating 41R overlapping with the red subpixel XR, electrodes 22G and the first coating 41G overlapping with the green subpixel XG, and electrodes 22B and the first coating 41B overlapping with the blue subpixel XB are formed, respectively. Therefore, upon completion of step S4, the manufacture of the electrode substrate 2, which includes the substrate 21, electrodes 22, and coating 4 including the first coating 41, is completed.

[0046] In this embodiment, the electrode 22 and the first coating 41 are formed by patterning the electrode layer 22L and the first coating layer 41L. Therefore, according to the above method, the accuracy of the formation position of the electrode 22 and the first coating 41 on the substrate 21 can be further improved. Furthermore, according to the above method, a coating 4 including the first coating 41 that covers the entire upper surface 22U of each electrode 22 can be formed by a simple method.

[0047] The patterning of the electrode layer 22L and the first coating layer 41L corresponds to the formation of electrodes at positions corresponding to each subpixel of the display device 1 on the substrate 21. In other words, this patterning includes the formation of each anode 31 of the light-emitting element layer 3. Therefore, according to the above method, part of the manufacturing process of the electrode substrate 2 and part of the formation process of the light-emitting element layer 3 can be shared, making the manufacturing of the display device 1 simpler.

[0048] Following the patterning of the electrode layer 22L and the first coating layer 41L, the bank BK shown in Figure 6 is formed (step S5). The bank BK may be formed by various methods, such as coating a photosensitive resin material and photolithography of the photosensitive resin material. In particular, in this embodiment, the bank BK is formed between the multiple electrodes 22 in a plan view of the substrate 21 and at a position overlapping with the periphery of the electrodes 22. This makes it possible to form a bank BK that covers the entire electrode side surface 22S of the electrode 22 and the periphery of the electrode top surface 22U of the electrode 22.

[0049] <Manufacturing method for display device: Formation of hole injection layer> Next, a hole injection layer 32 is formed (step S6). In step S6, for example, first, as shown in Figure 6, a hole injection material layer 32L is formed in a position that includes the side and top surface of the bank BK and on the coating 4 exposed from the bank BK (step S6-1). The formation of the hole injection material layer 32L may be carried out by applying a dispersion liquid containing the hole injection material described above to the respective parts of the bank BK and coating 4 on the substrate 21 by various methods.

[0050] In this case, the hole injection material layer 32L may contain a material that can corrode the electrode 22 by oxidizing it upon contact with the electrode 22. In particular, in stacked self-luminescent devices, the material contained in the hole injection layer 32 tends to be more corrosive to the electrode 22 than the material contained in other electron transport layers such as the electron transport layer 35. In this embodiment, the corrosion of the electrode 22 is reduced because a coating 4 is formed on a part of the surface of the electrode 22.

[0051] <Manufacturing Method for Display Device: Mechanism for Reducing Electrode Corrosion> The mechanism by which the coating 4 according to this embodiment reduces corrosion of the electrode 22 will be explained with further reference to Figure 7. Figure 7 is a schematic enlarged view of the side cross-section of the electrode substrate 2 and the hole injection material layer 32L to show the mechanism by which the first coating 41 of the coating 4 prevents corrosion of the electrode 22. Schematic enlarged views F1 and F2 of Figure 7 show enlarged parts of the side cross-sections of the electrode substrate 2 and the hole injection material layer 32L in step S6, and in particular show an enlarged view of a particular electrode 22 and the vicinity of said electrode 22.

[0052] As shown in the schematic enlarged diagram F1, the hole injection material layer 32L receives electron donation from a metal, etc., and oxidizes the metal. ｘ It may contain substances that function as oxidizing agents that oxidize other substances. However, in this embodiment, a coating 4 is formed on the electrode upper surface 22U of the electrode 22, which has a first coating 41 containing second metal atoms with a lower ionization energy than the first metal atoms contained in the electrode 22. Therefore, the hole injection material layer 32L comes into contact with the first coating 41 of the coating 4 instead of the electrode upper surface 22U of the electrode 22, and oxidizes the first coating 41.

[0053] For example, suppose that electrode 22 has silver atoms as the first metal atoms, and the first coating 41 has aluminum atoms as the second metal atoms. In this case, for example, the O of the hole injection material layer 32L ｘThe aluminum atoms receive electrons from the first coating 41, causing them to ionize. Since aluminum atoms have a lower ionization energy compared to silver atoms and readily donate electrons to other atoms, oxidation by the hole injection material layer 32L is more likely to occur in the first coating 41 than in the electrode 22. As a result, the electrode 22 is protected from corrosion by the hole injection material layer 32L, and the degradation of the electrode 22 is reduced.

[0054] Here, since the first coating 41 is a thin film on the order of several nanometers, it can be difficult to form a uniform film. In particular, as shown in schematic enlarged figure F2, pinholes 41H may be formed in the first coating 41 that communicate with the first coating 41 in the film thickness direction. In this case, even if the first coating 41 is formed on the upper electrode surface 22U of the electrode 22, the hole injection material layer 32L may come into direct contact with the electrode 22 through the pinholes 41H.

[0055] However, as described above, the first coating 41 has second metal atoms that are more likely to donate electrons to other atoms than the first metal atoms of the electrode 22. For this reason, in this embodiment, even when the hole injection material layer 32L is in contact with the electrode 22 as shown in schematic enlarged figure F2, electron donation from the second metal atoms of the first coating 41 to the hole injection material layer 32L is more likely to occur.

[0056] For example, as shown in schematic enlargement diagram F2, the aluminum atoms of the first coating 41 may ionize by donating electrons to the silver atoms of the electrode 22. Then, the silver atoms of the electrode 22 that received the donated electrons will use the O of the hole injection material layer 32L. ｘ It may also be supplied to the following. As a result, the hole injection material layer 32L corrodes only the aluminum atoms of the first coating 41, and the first coating 41 can reduce corrosion of the electrode 22.

[0057] Furthermore, a thin film of alumina, which is produced by the oxidation of aluminum atoms, may be formed on the surface of the first coating 41 on the side facing the hole injection material layer 32L. In addition, this thin film of alumina may function as a passivation agent for the hole injection material layer 32L, further reducing corrosion of the electrode 22.

[0058] As described above, the electrode substrate 2 reduces corrosion of the electrodes 22, for example, during the formation process of the hole injection layer 32. In this embodiment, the electrodes 22 of the electrode substrate 2 are the anodes 31 of the display device 1. Therefore, the display device 1 equipped with the electrode substrate 2 that reduces corrosion of the electrodes 22 improves the reliability of the light-emitting element and achieves a longer lifespan. In this embodiment, since the coating 4 covers the surface of multiple electrodes 22, the electrode substrate 2 reduces corrosion of each of the multiple electrodes 22.

[0059] In particular, when electrode 22 is the anode 31, the coating 4 reduces contact between the electrode 22 and materials that can corrode the electrode 22, such as the hole injection material layer 32L, during the manufacturing process of the display device 1. Therefore, the display device 1 according to this embodiment further reduces corrosion of the anode 31 of each light-emitting element.

[0060] In this embodiment, the coating 4 covers only the upper electrode surface 22U of the electrode 22 and does not cover the electrode side surface 22S of the electrode 22. However, in this embodiment, the electrode side surface 22S of the electrode 22 is covered by the bank BK. Therefore, the display device 1 reduces corrosion of the electrode 22 with the coating 4, while reducing corrosion of the electrode 22 from the electrode side surface 22S by the bank BK.

[0061] On the other hand, the coating 4 covers the entire upper surface 22U of the electrode 22. In this case, as described above, the coating 4 can reduce direct contact between the electrode 22 and materials that can corrode the electrode 22, such as the hole injection material layer 32L. Therefore, the electrode substrate 2 further reduces corrosion of the electrode 22 due to the coating 4.

[0062] In this embodiment, the electrodes 22, which are reflective electrodes of each light-emitting element of the display device 1, may contain silver atoms, and the first coating 41 may contain aluminum atoms, which have a lower ionization energy than silver atoms. Generally, the light reflectance on the surface of a metal thin film containing silver atoms tends to be higher than that on the surface of a metal thin film containing other metal atoms. Therefore, with the above configuration, the electrode substrate 2 reflects light from each light-emitting element of the display device 1 more strongly at the electrode upper surface 22U of the electrode 22, improving the efficiency of light extraction from each light-emitting element, while the corrosion of the electrode 22 is further reduced by the first coating 41.

[0063] <Manufacturing method for display device: After formation of hole transport layer> Referring to Figures 3 and 6, the explanation of the method for forming the hole injection layer 32 is as follows: Following the formation of the hole injection material layer 32L, the solvent of the hole injection material layer 32L is volatilized (step S6-2). Step S6-2 may be achieved, for example, by heating various parts on the substrate 21. The formation of the hole injection layer 32 is thus completed.

[0064] Next, a hole transport layer 33 is formed, for example, by a coating method (step S7). Then, a light-emitting layer 34 is formed (step S8). The light-emitting layer 34 may be formed, for example, by repeating the process of forming a layer of light-emitting material that emits light in a specific color, and patterning the layer, for the number of times corresponding to the number of light-emitting colors of each light-emitting element of the display device 1. Alternatively, the light-emitting layer 34 may be formed by coating a light-emitting material of a specific color for each sub-pixel using an inkjet method or the like.

[0065] Next, an electron transport layer 35 is formed by, for example, a coating method (step S9). Then, a cathode 36 is formed by sputtering or CVD (step S10). As a result, the light-emitting element layer 3 is formed on the substrate 21, and the manufacturing of the display device 1 is completed. According to the above method, an electrode substrate 2 that reduces corrosion of the electrode 22 can be manufactured, and a display device 1 equipped with the electrode substrate 2 can be manufactured.

[0066] In this embodiment, an example was described in which the coating 4 reduces corrosion of the electrode 22 caused by the hole injection material layer 32L. However, the corrosion of the electrode 22 reduced by the coating 4 is not limited to that caused by the hole injection material layer 32L. For example, the coating 4 may reduce corrosion of the electrode 22 caused by moisture or air penetrating from outside the display device 1 toward the electrode 22.

[0067] [Embodiment 2] <Another example of a bank> Figure 8 is a schematic side cross-sectional view of the display device 1 according to this embodiment. The display device 1 according to this embodiment differs from the display device 1 according to the previous embodiment in that the bank BK is formed on the hole transport layer 33. For this reason, the bank BK partitions the light-emitting layer 34 into subpixels, but is not located between the anodes 31.

[0068] In this embodiment, a hole injection layer 32 is positioned between the multiple anodes 31. Therefore, the multiple anodes 31, in other words, the electrodes 22, are separated by the hole injection layer 32. Also, the first coating 41 of the coating 4 is separated by the hole injection layer 32. As a result, the electrode side surface 22S of each of the multiple electrodes 22 is covered by the hole injection layer 32, and the side surfaces of the multiple first coatings 41 are also covered by the hole injection layer 32.

[0069] Except as described above, the display device 1 according to this embodiment has the same configuration as the display device 1 according to the previous embodiment. In particular, in this embodiment as well, the electrode substrate 2 is provided with a coating 4 including a first coating 41 that covers the upper surface 22U of each electrode 22. Therefore, the electrode substrate 2 reduces corrosion of the electrode 22.

[0070] The display device 1 according to this embodiment may be manufactured by modifying a part of the manufacturing method of the display device 1 according to the previous embodiment. The manufacturing method of the display device 1 according to this embodiment will be described with reference to Figures 9 and 10. Figure 9 is a flowchart showing the manufacturing method of the display device 1 according to this embodiment. Figure 10 is a cross-sectional view of the process in the manufacturing method of the display device 1 according to this embodiment.

[0071] In the manufacturing method of the display device 1 according to this embodiment, steps S1 to S4 described above are performed first. This produces the electrode substrate 2 shown in Figure 10. In this embodiment, step S6 is performed after step S4. Therefore, in step S6-1 according to this embodiment, as shown in Figure 10, since the bank BK is not located between the multiple electrodes 22, the hole injection material layer 32L also comes into contact with the electrode side surface 22S of the electrode 22.

[0072] However, even when the hole injection material layer 32L and the electrode side surface 22S of the electrode 22 come into contact, as in step S6-1 of this embodiment, the first coating 41 reduces corrosion of the electrode 22 from the electrode side surface 22S due to the mechanism described above. Therefore, the electrode substrate 2 can reduce corrosion of the electrode 22 with the first coating 41 that covers only the electrode upper surface 22U of the electrode 22, thus reducing corrosion of the electrode 22 with a simpler coating 4 configuration.

[0073] Next, by performing step S6-2, a hole injection layer 32 that partitions the multiple electrodes 22 can be formed, as shown in Figure 10. Then, by performing steps S7 and S5 in that order, a bank BK can be formed on the hole transport layer 33. Subsequently, by performing steps S8 to S10 in order, the display device 1 according to this embodiment can be manufactured.

[0074] [Embodiment 3] <Coating covering a portion of the electrode top surface> Figure 11 is a schematic side cross-sectional view F3 of the display device 1 according to this embodiment and a schematic plan view F4 of the electrode substrate 2. The display device 1 according to this embodiment differs from the display device 1 according to Embodiment 1 in that the coating 4, in particular the first coating 41 of the coating 4, covers only a portion of the electrode top surface 22U of each electrode 22. In particular, in this embodiment, as shown in schematic plan view F4, the first coating 41 covers the periphery of the electrode top surface 22U of each electrode 22.

[0075] Therefore, in this embodiment, as shown in the schematic side cross-sectional view F3, the hole injection layer 32 is in contact with a part of the upper surface 22U of each anode 31, in other words, of each electrode 22. Also, a part of the first coating 41 is exposed from the bank BK in a plan view. Therefore, the first coating 41 is in contact with the hole injection layer 32.

[0076] Except as described above, the display device 1 according to this embodiment may have the same configuration as the display device 1 according to Embodiment 1.

[0077] The display device 1 according to this embodiment may be manufactured by modifying a part of the manufacturing method of the display device 1 according to Embodiment 1. The manufacturing method of the display device 1 according to this embodiment will be described with reference to Figure 12. Figure 12 is a cross-sectional view of the process in the manufacturing method of the display device 1 according to this embodiment.

[0078] In the manufacturing method of the display device 1 according to this embodiment, steps S1 to S4-1 described above are performed first. This forms the substrate 21, electrode layer 22L, first coating layer 41L, and resist R1 shown in Figure 12. Next, in this embodiment, patterning of the resist R1 is performed in step S4-2. In step S4-2 according to this embodiment, the resist R1 located between a plurality of subpixels in a plan view of the substrate 21 is removed.

[0079] In addition, in step S4-2 of this embodiment, as shown in Figure 12, resist R1 is patterned such that resist R2 remains at the periphery of the position corresponding to each subpixel, and resist R3, which has a smaller film thickness than resist R2, remains closer to the center than the periphery. The patterning in step S4-2 of this embodiment may be achieved, for example, by photolithography using a halftone mask. Alternatively, in step S4, resist R2 and resist R3 may be formed by performing the coating of resist R1 and the patterning of the coated resist R1 multiple times.

[0080] As a result, a resist R2 that overlaps with the periphery of each subpixel in a plan view of the substrate 21, and a resist R3 that is thinner than resist R2 and is located closer to the center than resist R2 in a plan view of the substrate 21 are formed on the first coating layer 41L. Next, in step S4-3, patterning of the electrode layer 22L and the first coating layer 41L is performed by, for example, dry etching from the side of resist R2 and resist R3 rather than the substrate 21.

[0081] Here, since the resist R3 has a smaller film thickness than resist R2, etching proceeds before resist R2 by the dry etching method described above. Therefore, in step S4-3, the portion of the first coating layer 41L that was located directly beneath resist R3 in step S4-2 is etched. As a result, as shown in Figure 12, after the completion of step S4-3, only the portion of the first coating layer 41L located at the periphery of each subpixel in a plan view of the substrate 21 remains, forming the first coating 41 according to this embodiment, and thus manufacturing the electrode substrate 2.

[0082] Subsequently, the display device 1 according to this embodiment is manufactured by executing the steps S5 to S10 described above in order. In step S5, since the electrode upper surface 22U of each electrode 22 is exposed from the first coating 41, the hole injection material layer 32L is in contact with the electrode upper surface 22U of each electrode 22. However, in step S5, since a part of the first coating 41 is exposed from the bank BK, a part of the first coating 41 is in contact with the hole injection material layer 32L. Therefore, in step S5 according to this embodiment, as shown in the schematic enlarged view F2 of Figure 7, the corrosion of the portion of the electrode 22 that is in contact with the hole injection material layer 32L can be reduced by the mechanism described above.

[0083] Therefore, the electrode substrate 2 according to this embodiment reduces corrosion of the electrode 22 by the coating 4. Furthermore, the portion of the electrode upper surface 22U of the electrode 22 that is exposed from the coating 4 in a plan view of the substrate 21 does not have the coating 4 present, and therefore reflects light from, for example, the light-emitting layer 34 more strongly. Thus, the electrode substrate 2 according to this embodiment can reduce corrosion of the electrode 22 by the coating 4 while reflecting light more strongly on the electrode upper surface 22U of the electrode 22. The display device 1 equipped with the electrode substrate 2 according to this embodiment improves the reliability of each light-emitting element while improving the efficiency of light extraction from each light-emitting element.

[0084] In particular, the coating 4 covers the periphery of the electrode upper surface 22U of each electrode 22 in a plan view of the substrate 21, causing the electrode substrate 2 to reflect light more strongly on the side of the center of the electrode upper surface 22U of each electrode 22 in a plan view of the substrate 21. Therefore, the display device 1 equipped with the electrode substrate 2 according to this embodiment improves the reliability of each light-emitting element and reduces stray light by improving the accuracy of the position from which light is extracted from each light-emitting element.

[0085] [Embodiment 4] <Second Coating> Figure 13 is a schematic side cross-sectional view of the display device 1 according to this embodiment. The display device 1 according to this embodiment differs in configuration from the display device 1 according to Embodiment 1 in that the coating 4 further includes a second coating 42. The second coating 42 covers a part of the first coating. For example, the second coating 42 covers a part of the upper surface 41U of the first coating 41 on the side opposite to the substrate 21 in the film thickness direction DT, but does not cover the side surface 41S of the first coating 41, which is the end face of the first coating 41 in the planar direction DP. In particular, the second coating 42 covers only a part of the upper surface 41U of the first coating 41.

[0086] Furthermore, the second coating 42 has a third metal atom whose ionization energy is lower than that of the second metal atom present in the first coating 41. If the first metal atom present in the electrode 22 is a silver atom and the second metal atom present in the first coating 41 is an aluminum atom, the third metal atom present in the second coating 42 may be a magnesium atom.

[0087] The second coating 42 may be a thin metal film. Also, from the same viewpoint as described above, the thickness of the second coating 42 in the thickness direction DT may be 1 nm or more and 50 nm or less. Alternatively, the total thickness of the coating 4, which is the sum of the first coating 41 and the second coating 42 in the thickness direction DT, may be 1 nm or more and 100 nm or less. Furthermore, the second coating 42 may be in contact with the hole injection layer 32.

[0088] Except as described above, the display device 1 according to this embodiment may have the same configuration as the display device 1 according to Embodiment 1.

[0089] The display device 1 according to this embodiment may be manufactured by modifying a part of the manufacturing method of the display device 1 according to Embodiment 1. The manufacturing method of the display device 1 according to this embodiment will be described with reference to Figures 14 to 16. Figure 14 is a flowchart showing the manufacturing method of the display device 1 according to this embodiment. Figures 15 and 16 are cross-sectional views of the process in the manufacturing method of the display device 1 according to this embodiment.

[0090] In the manufacturing method of the display device 1 according to this embodiment, steps S1 to S3 described above are performed first. This forms the substrate 21, electrode layer 22L, and first coating layer 41L shown in Figure 15. Next, in this embodiment, a second coating layer 42L is formed on the first coating layer 41L (step S11). In particular, the second coating layer 42L has the third metal atom described above. The second coating layer 42L may be a thin metal film. The second coating layer 42L may be formed by various film formation methods including sputtering, and may be formed by the same method as the first coating layer 41L, except that the type of metal atom it contains is different.

[0091] Next, the electrode layer 22L, the first coating layer 41L, and the second coating layer 42L are patterned (step S12). In step S12, first, as shown in Figure 5, a resist R1 is deposited on the second coating layer 42L, for example, by the same method as in step S4-1 (step S12-1). Next, as shown in Figure 5, the resist R1 is patterned (step S12-2). In step S12-2 according to this embodiment, for example, the resist R1 located between a plurality of subpixels in a plan view of the substrate 21 is removed by the same method as in step S4-2 described above. In addition, in step S12-2 according to this embodiment, as shown in Figure 16, the resist R1 is patterned such that resist R2 remains at the center of the position corresponding to each subpixel, and resist R4, which has a smaller film thickness than resist R2, remains on the peripheral side of the center. The patterning in step S12-2 according to this embodiment may be achieved by, for example, photolithography using a halftone mask.

[0092] Next, the electrode layer 22L, the first coating layer 41L, and the second coating layer 42L are etched from the side of the resists R2 and R4 rather than the substrate 21 (step S12-3). In step S4-3, patterning of the electrode layer 22L, the first coating layer 41L, and the second coating layer 42L is performed, for example, by performing dry etching or the like from the side of the resists R2 and R3 rather than the substrate 21.

[0093] Here, since the resist R4 has a smaller film thickness than resist R2, etching proceeds before resist R2 by the dry etching method described above. Therefore, in step S12-3, the portion of the second coating layer 42L that was located directly beneath resist R4 in step S12-2 is etched. As a result, as shown in Figure 16, after the completion of step S4-3, only the portion of the second coating layer 42L located at the center of each subpixel in a plan view of the substrate 21 remains, and the second coating 42 according to this embodiment is formed. On the other hand, in step S12-3, the first coating layer 41L may remain on the entire surface of the electrode upper surface 22U of the electrode 22. As a result, the electrode 22, the first coating 41, and the second coating 42 are formed on the substrate 21, and the electrode substrate 2 is manufactured.

[0094] Subsequently, the display device 1 according to this embodiment is manufactured by executing the steps S6 to S10 described above in order. In step S6 of this embodiment, the hole injection material layer 32L comes into contact with both the first coating 41 and the second coating 42. As a result, through a mechanism described later, the second coating 42 reduces corrosion of the first coating 41, and consequently increases the effect of the coating 4 in reducing corrosion of the electrode 22.

[0095] The mechanism by which the coating 4 according to this embodiment reduces corrosion of the electrode 22 will be further explained with reference to Figure 17. Figure 17 is a schematic enlarged view of the side cross-section of the electrode substrate 2 and the hole injection material layer 32L to illustrate the mechanism by which the first coating 41 of the coating 4 prevents corrosion of the electrode 22. Figure 17 shows an enlarged portion of the side cross-section of the electrode substrate 2 and the hole injection material layer 32L in step S6 according to this embodiment, and in particular shows an enlarged view of one electrode 22 and the vicinity of said electrode 22.

[0096] As shown in Figure 17, the hole injection material layer 32L is in contact with both the first coating 41 and the second coating 42. Here, the second coating 42 has a third metal atom having a lower ionization energy than the second metal atom of the first coating 41. Therefore, in step S6 according to this embodiment, ionization of the third metal atom of the second coating 42 is more likely to occur than ionization of the second metal atom of the first coating 41.

[0097] For example, suppose the first coating 41 has aluminum atoms as the second metal atoms, and the second coating 42 has magnesium atoms as the third metal atoms. In this case, as shown in Figure 17, the magnesium atoms of the second coating 42 may ionize by donating electrons to the aluminum atoms of the first coating 41. Then the aluminum atoms of the first coating 41 that have received electron donations the donated electrons into the O of the hole injection material layer 32L. ｘ It may also be supplied to the following. As a result, the hole injection material layer 32L corrodes only the magnesium atoms of the second coating 42, and the second coating 42 can reduce the corrosion of the first coating 41.

[0098] In this embodiment as well, the first coating 41 has second metal atoms with a lower ionization energy than the first metal atoms of the electrode 22, thereby reducing corrosion of the electrode 22 through the mechanism described above. In this embodiment, the corrosion of the first coating 41 is reduced by the second coating 42 through the mechanism described above. Therefore, the first coating 41, with its reduced corrosion, further reduces corrosion of the electrode 22. Thus, the electrode substrate 2 according to this embodiment further reduces corrosion of the electrode 22 with a coating 4 including the first coating 41 and the second coating 42.

[0099] The second coating 42 covers the upper surface 41U of the first coating 41, but does not cover the side surface 41S of the first coating. Therefore, the electrode substrate 2 can further reduce corrosion of the electrode 22 with a simpler coating 4 configuration. In particular, the second coating 42 covers only a portion of the upper surface 41U of the first coating 41. Therefore, the electrode substrate 2 can simplify the configuration of the coating 4 while reducing the total thickness of a portion of the coating 4 on the electrode 22, and can further increase light reflection on the upper surface 22U of the electrode in that portion.

[0100] In this embodiment, the electrodes 22, which are reflective electrodes of each light-emitting element of the display device 1, may have silver atoms. The first coating 41 may have aluminum atoms, which have a lower ionization energy than silver atoms, and the second coating 42 may have magnesium atoms, which have a lower ionization energy than aluminum atoms. In this case, the electrode substrate 2 improves the efficiency of light extraction from each light-emitting element of the display device 1 while further reducing corrosion of the electrodes 22 by the first coating 41 and the second coating 42.

[0101] The structure of the coating 4 on the electrode substrate 2 according to this embodiment can be obtained by patterning the electrode layer 22L, the first coating layer 41L, and the second coating layer 42L at the same time. Therefore, according to the above-described method for manufacturing the electrode substrate 2, an electrode substrate 2 equipped with a coating 4 that further reduces corrosion of the electrode 22 can be manufactured using a simpler manufacturing method.

[0102] This disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this disclosure. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

[0103] 1 Display device 2 Electrode substrate 3B Blue light emitting element 3G Green light emitting element 3R Red light emitting element 4 Coating 21 Substrate 22 Electrode 22L Electrode layer 22S Electrode side surface 22U Electrode top surface 31 Anode 32 Hole injection layer 34 Light emitting layer 36 Cathode 41 First coating 41L First coating layer 41S First coating side surface 41U First coating top surface 42 Second coating 42L Second coating layer

Claims

1. An electrode substrate comprising: a substrate; at least one electrode located on the substrate and having a first metal atom; and a coating covering at least one of the electrode's surface, specifically a portion of the electrode's upper surface and a portion of the electrode's side surface located on the side opposite to the substrate, wherein the coating includes a first coating that is in contact with the portion of the electrode's surface and has a second metal atom having a lower ionization energy than the first metal atom.

2. The electrode substrate according to claim 1, wherein the coating covers a portion of the upper surface of the electrode but does not cover the side surface of the electrode.

3. The electrode substrate according to claim 2, wherein the coating covers the entire upper surface of the electrode.

4. The electrode substrate according to claim 2, wherein the coating covers only a portion of the upper surface of the electrode.

5. The electrode substrate according to claim 4, wherein, in a plan view of the substrate, the coating covers the periphery of the upper surface of the electrode.

6. The electrode substrate according to any one of claims 1 to 5, wherein the first metal atom is a silver atom and the second metal atom is an aluminum atom.

7. The electrode substrate according to any one of claims 1 to 5, wherein the coating comprises a second coating that covers a portion of the first coating, is in contact with a portion of the surface of the first coating, and has a third metal atom having a lower ionization energy than the second metal atom.

8. The electrode substrate according to claim 7, wherein the second coating covers a portion of the upper surface of the first coating on the side opposite to the substrate, but does not cover the side surface of the first coating.

9. The electrode substrate according to claim 8, wherein the second coating covers only a portion of the upper surface of the first coating.

10. The electrode substrate according to any one of claims 7 to 9, wherein the first metal atom is a silver atom, the second metal atom is an aluminum atom, and the third metal atom is a magnesium atom.

11. The electrode substrate according to any one of claims 1 to 10, wherein a plurality of electrodes are provided, and each of the plurality of electrodes is provided with the coating.

12. A display device comprising an electrode substrate according to claim 11, wherein a plurality of light-emitting elements are provided on the substrate, the light-emitting elements each comprising an anode, a cathode facing the anode, and a light-emitting layer between the anode and the cathode, and the anode or the cathode is the electrode.

13. The display device according to claim 12, wherein the anode is the electrode, and the light-emitting element is located between the electrode and the light-emitting layer and comprises a hole injection layer in contact with the coating on the electrode.

14. The display device according to claim 12 or 13, comprising a bank located on the substrate and partitioning the spaces between a plurality of the light-emitting elements, wherein the bank covers a portion of the upper surface and side surface of the plurality of electrodes, and the coating covers a portion of the portion of the upper surface of the electrodes that is exposed from the bank.

15. A method for manufacturing an electrode substrate, comprising: preparing a substrate; forming at least one electrode located on the substrate and having a first metal atom; and forming a coating that covers at least one of the electrode's surfaces, the electrode's upper surface located on the side opposite to the substrate and the electrode's side surface, wherein the formation of the coating includes forming a first coating having a second metal atom having a lower ionization energy than the first metal atom.

16. The method for manufacturing an electrode substrate according to claim 15, comprising: forming an electrode layer having the first metal atoms on the substrate; forming a first coating layer having the second metal atoms on the electrode layer; and patterning the electrode layer and the first coating layer.

17. The method for manufacturing an electrode substrate according to claim 15, wherein the formation of the coating comprises the formation of a second coating that covers a portion of the first coating and has a third metal atom having a lower ionization energy than the second metal atom.

18. A method for manufacturing an electrode substrate according to claim 17, comprising: forming the electrode, forming the first coating, and forming the second coating, the following steps: forming an electrode layer having the first metal atoms on the substrate; forming a first coating layer having the second metal atoms on the electrode layer; forming a second coating layer having the third metal atoms on the first coating layer; and patterning the electrode layer, the first coating layer, and the second coating layer.

Images