Display panel and display device

Abstract

To provide a display panel in which color purity is improved using a combination of optical resonator structure and a color filter.SOLUTION: A display panel is provided, comprising a plurality of pixels which include self-luminous elements and color filters facing the self-luminous elements, at least one of the plurality of self-luminous elements is a green light emitting element, the green light emitting element has a light transmissive metal film electrode, a green light emitting layer and a light reflective electrode laminated in an order close to the color filter to constitute optical resonator structure enhancing light intensity of a first wavelength, and a color filter facing the green light emitting element has light transmittance less than or equal to 50% for the light which has longer wavelength than the first wavelength and which has the second wavelength having a higher visibility characteristic as a green color than the first wavelength.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a display panel including a light-emitting element that utilizes an electroluminescence phenomenon or a quantum dot effect, and a display device that uses the display panel. [Background technology]

[0002] In recent years, display devices using light-emitting elements such as organic EL elements, which utilize the electroluminescence phenomenon of organic materials, and QLEDs, which utilize the quantum dot effect, have become increasingly popular. Light-emitting elements have a basic structure in which a light-emitting layer is placed between a pair of electrodes, and when a voltage is applied between the electrodes, holes and electrons recombine, causing the light-emitting layer to emit light.

[0003] A so-called top-emission light-emitting device, which emits light above the substrate, has a light-reflective electrode on the substrate side and a semi-transparent electrode on the opposite side. Part of the light generated in the light-emitting layer passes through the semi-transparent electrode and is emitted directly, while part of the light is reflected by the light-reflective electrode and semi-transparent electrode, propagates within the light-emitting device, and then emitted. A so-called resonator structure, in which the optical path length within the light-emitting device is designed so that these lights interfere constructively, is used to improve the light extraction efficiency.

[0004] In a color display panel, such light-emitting elements form sub-pixels of each color, RGB, and adjacent RGB sub-pixels combine to form a unit pixel for color display. Display panels using light-emitting elements generally employ a structure that suppresses reflection of external light to prevent a decrease in visibility due to reflection of external light from a reflective electrode provided in each pixel (see, for example, Patent Documents 1 to 3). Furthermore, a structure that combines a resonator structure with a color filter is used as a method for improving color purity (see, for example, Patent Document 4). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-32016 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-185992 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-183024 [Patent Document 4] International Publication No. 2001 / 39554 Summary of the Invention [Problem to be solved by the invention]

[0006] The structure described in Patent Document 4 aims to improve color purity by controlling the light intensity at the peak wavelength of light extracted from the light emitting element and wavelengths in the vicinity thereof. However, the structure described in Patent Document 4 has a problem in that color purity may decrease if there is a region in which the human visual sensitivity characteristic is high in a wavelength range that is not in the vicinity of the peak wavelength of light extracted from the light emitting element.

[0007] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a display panel that improves color purity by using a combination of an optical resonator structure and a color filter that does not adversely affect the aperture ratio or luminous efficiency. [Means for solving the problem]

[0008] A display panel according to one embodiment of the present disclosure is a display panel having a plurality of pixels each including a self-luminous element and a color filter facing the self-luminous element, wherein at least one of the plurality of self-luminous elements is a green light-emitting element, and the green light-emitting element has an optical resonator structure that enhances the light intensity of a first wavelength, in which a light-transmitting metal thin film electrode, a green light-emitting layer, and a light-reflective electrode are stacked in order from the element closest to the color filter, and the color filter facing the green light-emitting element has an optical transmittance of 50% or less for light of a second wavelength that is longer than the first wavelength and has a higher visual sensitivity characteristic as being greener than the first wavelength. [Effects of the Invention]

[0009] According to the display panel of the above aspect, the reflectance of the second wavelength light can be reduced for the pixels including the green light-emitting layer, thereby enabling the pixels including the green light-emitting layer to efficiently emit the desired light of the first wavelength and suppressing a decrease in color purity caused by the inclusion of the second wavelength light having high luminosity characteristics in the reflected external light. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view schematically illustrating a configuration of an organic EL display panel according to an embodiment. [Figure 2] 1 is a schematic cross-sectional view illustrating the interference of light in an optical resonator structure formed in an organic EL element 1. FIG. [Figure 3] (a) is a graph showing the emission spectrum of organic EL element 1 (G) and the transmission spectrum of a conventional color filter (G). (b) is a graph showing the Y value of the CIE color matching function. (c) is a graph showing the ambient light reflection characteristics of organic EL element (G) with an optical resonator structure. [Figure 4] Graph (a) shows the spectrum of reflected light when external light corresponding to light source C is incident on an organic EL element (G) having an optical resonator structure, and graph (b) shows the transmission spectrum of color filters (G) according to Examples 1 and 2 and a comparative example. [Figure 5] Graph (a) shows the spectrum of reflected light from subpixel 2 (G), and graph (b) shows the relationship between the 565 nm transmittance of color filter (G) and the light reflectance of subpixel 2 (G). [Figure 6] 4 is a flowchart showing a manufacturing process of the display panel according to the embodiment. [Figure 7] 1A and 1B are partial cross-sectional views schematically illustrating a part of the manufacturing process of a display panel according to an embodiment, in which (a) shows a state in which a TFT layer is formed on a substrate, (b) shows a state in which an interlayer insulating layer is formed on a substrate, (c) shows a state in which a pixel electrode material is formed on the interlayer insulating layer, (d) shows a state in which a pixel electrode is formed, and (e) shows a state in which a partition material layer is formed on the interlayer insulating layer and the pixel electrode. [Figure 8] 1A and 1B are partial cross-sectional views schematically illustrating a part of the manufacturing process of a display panel according to an embodiment, in which (a) shows a state in which a partition wall is formed, (b) shows a state in which a hole injection layer is formed on a pixel electrode, (c) shows a state in which a hole transport layer is formed on the hole injection layer, and (d) shows a state in which a light-emitting layer is formed on the hole injection layer. [Figure 9] 1A and 1B are partial cross-sectional views schematically illustrating a part of the manufacturing process of a display panel according to an embodiment, in which (a) shows a state in which an intermediate layer is formed on a light-emitting layer and a partition wall, (b) shows a state in which an electron injection transport layer is formed on the intermediate layer, (c) shows a state in which a counter electrode is formed on the electron injection transport layer, and (d) shows a state in which a sealing layer is formed on the counter electrode. [Figure 10] 10A and 10B are partial cross-sectional views showing a schematic diagram of a part of the manufacturing process of a display panel according to an embodiment, in which (a) shows a state in which a light-shielding material film is formed on an upper substrate, (b) shows a state in which a light-shielding screen is formed on an upper substrate, (c) shows a state in which a color filter is formed on an upper substrate, and (d) shows a state in which a color filter substrate is attached to a light-emitting element substrate. [Figure 11] 1 is a block diagram showing a configuration of a display device according to an embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0011] <<How one aspect of the present disclosure was achieved>> Display panels equipped with light-emitting elements are known to suffer from problems such as poor contrast and glare due to external light being reflected by electrodes. To address this issue, there are technologies for suppressing external light reflection, such as using a circular polarizer, and a technology for suppressing external light reflection by electrodes using a color filter layer with a black matrix, as described in Patent Document 4. However, because circular polarizers have light-absorbing properties and black matrices reduce the aperture ratio of the display panel, in either case, the luminous efficiency decreases, which can lead to increased power consumption and a shortened panel lifespan.

[0012] Meanwhile, as described in Patent Document 4, a technique for suppressing external light reflection using an optical resonator structure is also known. As shown in the schematic cross-sectional view of FIG. 2, the optical resonator structure adjusts the optical path so that light emitted directly from the light-emitting center via path C1 and light emitted via path C2, which is reflected from the light-emitting center through a semi-transparent electrode and a light-reflective electrode, reinforce each other. The optical resonator structure functions as a filter that increases the transmittance of light with the same wavelength as the extracted light, thereby reducing the reflectance of light with the same wavelength as the extracted light and suppressing contrast reduction against external light. Therefore, this configuration can improve contrast and increase optical purity at the wavelength of the extracted light and its neighboring wavelength bands. However, the optical resonator structure is ineffective for wavelength bands outside the wavelength of the extracted light and its neighboring wavelength bands. Therefore, if wavelengths with high human visual sensitivity exist in wavelength bands outside the wavelength of the extracted light, the structure does not function as a suppression structure for external light reflection for those wavelengths, resulting in insufficient color purity. In particular, in color panels that use the three colors RGB, the peak wavelength of green (G) light-emitting elements is around 530 nm, while the peak wavelength of the sensitivity of M cone cells (Y value in the CIE color matching function) is around 555 nm, so a decrease in color purity is likely to occur for green light-emitting elements.

[0013] In view of the above problems, the inventors have investigated a configuration that improves color purity by using a combination of an optical resonator structure and a color filter that does not adversely affect the aperture ratio or luminous efficiency, and have arrived at the present disclosure.

[0014] <<Mode of Disclosure>> A display panel according to one embodiment of the present disclosure is a display panel having a plurality of pixels each including a self-luminous element and a color filter facing the self-luminous element, wherein at least one of the plurality of self-luminous elements is a green light-emitting element, and the green light-emitting element has an optical resonator structure that enhances the light intensity of a first wavelength, in which a light-transmitting metal thin film electrode, a green light-emitting layer, and a light-reflective electrode are stacked in order from the element closest to the color filter, and the color filter facing the green light-emitting element has an optical transmittance of 50% or less for light of a second wavelength that is longer than the first wavelength and has a higher visual sensitivity characteristic as being greener than the first wavelength.

[0015] According to the display panel of the above aspect, the reflectance of the second wavelength light can be reduced for the pixels including the green light-emitting layer, thereby enabling the pixels including the green light-emitting layer to efficiently emit the desired light of the first wavelength and suppressing a decrease in color purity caused by the inclusion of the second wavelength light having high luminosity characteristics in the reflected external light.

[0016] Furthermore, the display panel according to the above aspect may be configured as follows.

[0017] In the CIE color matching functions, a Y value corresponding to the second wavelength may be greater than a Y value corresponding to the first wavelength.

[0018] The above aspect can suppress the influence of external light reflection of light of a second wavelength, which is easier to see than light of a first wavelength but has lower color purity. The first wavelength may be 530 nm or less, and the second wavelength may be in the range of 545 nm to 565 nm. The second wavelength may be a wavelength selected from the range of 545 nm to 565 nm. Therefore, for example, the first wavelength may be 530 nm or less, and the second wavelength may be 565 nm. Alternatively, the first wavelength may be 530 nm or less, and the second wavelength may be 555 nm. The first wavelength may be 530 nm or less, and the second wavelength may be 545 nm.

[0019] According to the above aspect, by using green light with high color purity as the first wavelength and suppressing external light reflection of light with the second wavelength, which is easy to see but has low color purity, it is possible to improve pixel contrast and increase color purity.

[0020] Furthermore, the color filter facing the self-luminous element may have a transmittance of 70% or more for light at the first wavelength.

[0021] According to the above aspect, it is possible to improve the light extraction efficiency without reducing the brightness of the light of the first wavelength, and also to increase the color purity.

[0022] In addition, in the display panel, the pixel including the green light emitting element may have an aperture ratio of 50% or more.

[0023] According to the above aspect, the life of the display panel can be extended.

[0024] Furthermore, a display panel according to one embodiment of the present disclosure is a display panel having a plurality of pixels each including a self-luminous element and a color filter facing the self-luminous element, wherein at least one of the plurality of self-luminous elements is a green light-emitting element, and the green light-emitting element has an optical resonator structure that enhances the light intensity of a first wavelength, in which a light-transmitting metal thin film electrode, a green light-emitting layer, and a light-reflective electrode are stacked in order from the side closest to the color filter, and the pixel including the green light-emitting element further has a second filter having an optical transmittance of 50% or less for light of a second wavelength that is longer than the first wavelength and has a higher visual sensitivity characteristic as being greener than the first wavelength.

[0025] In the display panel of the above aspect, the reflectance of the second wavelength light can be suppressed for the pixels including the green light-emitting layer, so that the desired light of the first wavelength can be efficiently emitted from the pixels including the green light-emitting layer, and a decrease in color purity caused by the light of the second wavelength having high luminosity characteristics being included in the reflected external light can be suppressed.

[0026] A display device according to an aspect of the present disclosure is a display panel including the display panel according to an aspect of the present disclosure.

[0027] According to the above aspect, a display device that exhibits the same effects as the display panel according to one aspect of the present disclosure can be realized.

[0028] Furthermore, a method for manufacturing a display panel according to one embodiment of the present disclosure includes forming a plurality of light-reflective electrodes on a substrate, forming a light-emitting layer above each of the plurality of light-reflective electrodes, forming a light-transmitting metal thin film electrode above the plurality of light-emitting layers to form an optical resonator structure, and forming a color filter above the metal thin film electrode and above each of the plurality of light-emitting layers, wherein in forming the light-emitting layers, at least one light-emitting layer is a green light-emitting layer, and in forming the color filters, the transmission characteristics of the color filter above the green light-emitting layer are such that, when the peak wavelength of the optical resonator structure is a first wavelength, the light transmittance is 50% or less for light of a second wavelength that is longer than the first wavelength and has a higher luminosity characteristic as being greener than the first wavelength.

[0029] In the display panel manufactured by the display panel manufacturing method of the above aspect, the reflectance of the second wavelength can be reduced for the pixels including the green light-emitting layer, so that the desired light of the first wavelength can be efficiently emitted from the pixels including the green light-emitting layer, and a decrease in color purity caused by the light of the second wavelength having high luminosity characteristics being included in the reflected light of external light can be suppressed.

[0030] <Embodiment> An embodiment of a display panel according to the present disclosure will be described below. Note that the following description is an example for explaining the configuration and functions and effects according to one aspect of the present disclosure, and the essential parts of the present disclosure are not limited to the following embodiment. Furthermore, in this specification and claims, including the following description, "up" and "down" indicate a relative positional relationship based on the light emission direction, and do not necessarily correspond to an absolute (vertical) positional relationship of up and down. Furthermore, in this specification and claims, the symbol "~" used to indicate a numerical range includes both ends of the range.

[0031] 1. Display panel overview FIG. 1 is a partial cross-sectional view of an organic EL display panel 100 (see FIG. 11) as a display panel according to an embodiment. The organic EL display panel 100 includes a plurality of pixels each composed of sub-pixels 2(R), 2(G), and 2(B) that emit three colors (red, green, and blue). The organic EL display panel 100 includes a light-emitting element substrate 30 including organic EL elements 1(R), 1(G), and 1(B) as light-emitting elements, and a color filter substrate 40 including a color filter and a black matrix. The combination of the organic EL element 1(R) and color filter 43(R) forms sub-pixel 2(R), the combination of the organic EL element 1(G) and color filter 43(G) forms sub-pixel 2(G), and the combination of the organic EL element 1(B) and color filter 43(B) forms sub-pixel 2(B). FIG. 1 shows a cross-section of one pixel composed of one each of sub-pixels 2(R), 2(G), and 2(B).

[0032] In the organic EL display panel 100, each organic EL element 1 is of a so-called top emission type that emits light forward (upward in the z direction in FIG. 1).

[0033] The organic EL element 1(R), the organic EL element 1(G), and the organic EL element 1(B) have almost the same configuration, and therefore will be described as the organic EL element 1 when no distinction is required.

[0034] 2.Detailed configuration of the display panel (2.1) Configuration of the Light Emitting Device Substrate 30 1, the organic EL element 1 includes a substrate 11, an interlayer insulating layer 12, a pixel electrode 13, a partition wall 14, a hole injection layer 15, a hole transport layer 16, an emitting layer 17, an intermediate layer 18, an electron injection transport layer 19, a counter electrode 20, and a sealing layer 21. The pixel electrode 13 and the counter electrode 20 correspond to the light-reflective electrode and the light-semitransparent electrode of the present disclosure, respectively.

[0035] The substrate 11, the interlayer insulating layer 12, the intermediate layer 18, the electron injection transport layer 19, the counter electrode 20, and the sealing layer 21 are not formed for each pixel, but are formed in common for the multiple organic EL elements 1 included in the light-emitting element substrate 30.

[0036] <Substrate> The substrate 11 includes a base material 111 made of an insulating material and a TFT (Thin Film Transistor) layer 112. A drive circuit is formed in the TFT layer 112 for each sub-pixel. The base material 111 may be, for example, a glass substrate, a quartz substrate, or a plastic substrate. The plastic material may be either a thermoplastic resin or a thermosetting resin. Examples of suitable plastic materials include polyimide (PI), polyetherimide (PEI), polysulfone (PSu), polycarbonate (PC), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN). Examples include various thermoplastic elastomers such as polybutylene terephthalate, styrene-based, polyolefin-based, and polyurethane-based elastomers, epoxy resin, unsaturated polyester, silicone resin, polyurethane, etc., or copolymers, blends, and polymer alloys mainly made of these. A material selected from these materials has durability against the process temperature, and one or more laminates of these materials can be used.

[0037] <Interlayer insulating layer> The interlayer insulating layer 12 is formed on the substrate 11. The interlayer insulating layer 12 is made of a resin material and serves to flatten steps on the upper surface of the TFT layer 112. Examples of the resin material include a positive photosensitive material. Examples of such photosensitive materials include acrylic resins, polyimide resins, siloxane resins, and phenolic resins. Although not shown in the cross-sectional view of FIG. 1, a contact hole is formed in the interlayer insulating layer 12 for each subpixel.

[0038] <Pixel electrode> The pixel electrodes 13 are formed on the interlayer insulating layer 12. The pixel electrodes 13 are provided for each pixel, and are electrically connected to the TFT layer 112 through contact holes provided in the interlayer insulating layer 12.

[0039] In this embodiment, the pixel electrode 13 functions as a light-reflective anode.

[0040] Specific examples of metal materials that have light reflectivity include Ag (silver), Al (aluminum), aluminum alloys, Mo (molybdenum), APC (an alloy of silver, palladium, and copper), ARA (an alloy of silver, rubidium, and gold), MoCr (an alloy of molybdenum and chromium), MoW (an alloy of molybdenum and tungsten), and NiCr (an alloy of nickel and chromium).

[0041] The pixel electrode 13 may be composed of a metal layer alone, or may have a laminated structure in which a layer made of a metal oxide such as ITO (indium tin oxide) or IZO (indium zinc oxide) is laminated on the metal layer.

[0042] <Bulkhead> The partition wall 14 is formed on the pixel electrode 13, exposing a portion of the upper surface of the pixel electrode 13 and covering the surrounding area. The areas of the upper surface of the pixel electrode 13 that are not covered by the partition wall 14 (hereinafter referred to as "openings") correspond to subpixels. That is, the partition wall 14 has openings 14a provided for each subpixel.

[0043] In this embodiment, the partition wall 14 is formed on the interlayer insulating layer 12 in a portion where the pixel electrode 13 is not formed. That is, in a portion where the pixel electrode 13 is not formed, the bottom surface of the partition wall 14 is in contact with the upper surface of the interlayer insulating layer 12.

[0044] The partition walls 14 are made of, for example, an insulating organic material (for example, an acrylic resin, a polyimide resin, a novolac resin, or a phenolic resin). The partition walls 14 function as structures to prevent the applied ink from overflowing when the light-emitting layer 17 is formed by a coating method, and function as structures on which to place a deposition mask when the light-emitting layer 17 is formed by a deposition method. In this embodiment, the partition walls 14 are made of a resin material, and examples of the material for the partition walls 14 include acrylic resins, polyimide resins, siloxane resins, and phenolic resins. In this embodiment, a phenolic resin is used.

[0045] <Hole injection layer> The hole injection layer 15 is provided on the pixel electrode 13 for the purpose of promoting the injection of holes from the pixel electrode 13 to the light-emitting layer 17. Specific examples of materials for the hole injection layer 15 include conductive polymer materials such as PEDOT / PSS (a mixture of polythiophene and polystyrene sulfonic acid).

[0046] The hole injection layer 15 may be formed of an oxide of a transition metal. Specific examples of transition metals include Ag (silver), Mo (molybdenum), Cr (chromium), V (vanadium), W (tungsten), Ni (nickel), and Ir (iridium). Transition metals can take multiple oxidation numbers and therefore multiple levels, which facilitates hole injection and contributes to reducing the driving voltage. In this case, it is preferable that the hole injection layer 15 has a large work function.

[0047] The hole injection layer 15 may have a laminated structure in which a conductive polymer material is laminated on an oxide of a transition metal.

[0048] <Hole transport layer> The hole transport layer 16 has the function of transporting holes injected from the hole injection layer 15 to the light emitting layer 17, and is made of an organic material with high hole mobility in order to efficiently transport holes from the hole injection layer 15 to the light emitting layer 17. The hole transport layer 16 is formed by applying and drying an organic material solution. The organic material that can be used to form the hole transport layer 16 may be a polymer compound such as polyfluorene or a derivative thereof, or polyarylamine or a derivative thereof.

[0049] The hole transport layer 16 may also be formed using triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, porphyrin compounds, aromatic tertiary amine compounds and styrylamine compounds, butadiene compounds, polystyrene derivatives, hydrazone derivatives, triphenylmethane derivatives, and tetraphenylbenzene derivatives. Porphyrin compounds, aromatic tertiary amine compounds, and styrylamine compounds are particularly preferred. In this case, the hole transport layer 16 is formed by vacuum deposition. The materials and manufacturing method of the hole transport layer 16 are not limited to those described above. Any material having hole transport properties may be used, and any manufacturing method that can be used to manufacture the hole transport layer 16 may be used.

[0050] <Light-emitting layer> The light-emitting layer 17 is formed in the opening 14a. The light-emitting layer 17 has a function of emitting light of each color R, G, and B by recombination of holes and electrons. Known materials can be used as the material for the light-emitting layer 17.

[0051] When the light-emitting element 1 is an organic EL element, examples of the organic light-emitting material contained in the light-emitting layer 17 include oxinoid compounds, perylene compounds, coumarin compounds, azacoumarin compounds, oxazole compounds, oxadiazole compounds, perinone compounds, pyrrolopyrrole compounds, naphthalene compounds, anthracene compounds, fluorene compounds, fluoranthene compounds, tetracene compounds, pyrene compounds, coronene compounds, quinolone compounds and azaquinolone compounds, pyrazoline derivatives and pyrazolone derivatives, rhodamine compounds, chrysene compounds, phenanthrene compounds, cyclopentadiene compounds, and the like. Fluorescent materials that can be used include compounds such as stilbene compounds, diphenylquinone compounds, styryl compounds, butadiene compounds, dicyanomethylenepyran compounds, dicyanomethylenethiopyran compounds, fluorescein compounds, pyrylium compounds, thiapyrylium compounds, selenapyrylium compounds, telluropyrylium compounds, aromatic aldadiene compounds, oligophenylene compounds, thioxanthene compounds, cyanine compounds, acridine compounds, metal complexes of 8-hydroxyquinoline compounds, metal complexes of 2-bipyridine compounds, complexes of Schiff salts with Group III metals, oxine metal complexes, and rare earth complexes. Known phosphorescent materials, such as phosphorescent metal complexes of tris(2-phenylpyridine)iridium, can also be used. The light-emitting layer 17 can also be formed using polymeric compounds such as polyfluorenes and their derivatives, polyphenylenes and their derivatives, or polyarylamines and their derivatives, or mixtures of these low-molecular-weight compounds and these polymeric compounds. The light-emitting element 1 may be an inorganic EL element, and an inorganic light-emitting material may be used as the material of the light-emitting layer 17. The light-emitting element 1 may also be a quantum-dot light-emitting diode (QLED), and the light-emitting layer 17 may be made of a material having a quantum dot effect.

[0052] <Middle class> The intermediate layer 18 is formed on the light-emitting layer 17 and contains a fluoride or quinolinium complex of a metal material having electron injection properties. The metal material is selected from alkali metals and alkaline earth metals. Specific examples of alkali metals include Li (lithium), Na (sodium), K (potassium), Rb (rubidium), Cs (cesium), and Fr (francium). Specific examples of alkaline earth metals include Ca (calcium), Sr (strontium), Ba (barium), and Ra (radium). In this embodiment, NaF (sodium fluoride) is included.

[0053] <Electron injection transport layer> The electron injection transport layer 19 is formed on the intermediate layer 18 and is formed by doping an organic material having electron transport properties with a metal material that improves electron injection properties. Here, "doping" refers to dispersing metal atoms or metal ions of the metal material approximately uniformly throughout the organic material, specifically, forming a single phase containing the organic material and a trace amount of the metal material. It is preferable that no other phases, particularly phases consisting solely of the metal material, such as metal flakes or metal films, or phases primarily composed of the metal material, are present. In addition, in the single phase containing the organic material and a trace amount of the metal material, the concentration of the metal atoms or metal ions is preferably uniform, and the metal atoms or metal ions are preferably not aggregated. The metal material is preferably selected from rare earth metals, and Yb (ytterbium) is more preferable. In this embodiment, Yb is selected. The doping amount of the metal material in the electron injection transport layer 19 is preferably 3 to 60 wt %. In this embodiment, it is 20 wt %.

[0054] Examples of organic materials having electron transport properties include π-electron low-molecular organic materials such as oxadiazole derivatives (OXD), triazole derivatives (TAZ), and phenanthroline derivatives (BCP, Bphen).

[0055] <Counter electrode> The counter electrode 20 is made of a semi-transparent conductive material and is formed on the electron injecting and transporting layer 19. In this embodiment, the counter electrode 20 functions as a cathode.

[0056] The light-reflecting surface at the interface between the counter electrode 20 and the electron injecting transport layer 19 forms a pair with the light-reflecting surface at the interface between the pixel electrode 13 and the hole injecting layer 15, forming a resonator structure. Therefore, when light emitted from the light-emitting layer 17 enters the counter electrode 20 from the electron injecting transport layer 19, a portion of the light must be reflected back to the electron injecting transport layer 19. Therefore, it is preferable that the refractive index differs between the counter electrode 20 and the electron injecting transport layer 19. Therefore, the counter electrode 20 is preferably a metal thin film. To ensure semi-transparency, the thickness of the metal layer is approximately 1 nm to 50 nm.

[0057] Examples of materials for the counter electrode 20 include Ag, a silver alloy containing Ag as the main component, Al, and an Al alloy containing Al as the main component. Examples of Ag alloys include magnesium-silver alloy (MgAg) and indium-silver alloy. Ag basically has low resistivity, and Ag alloys are preferable because they have excellent heat resistance and corrosion resistance and can maintain good electrical conductivity for a long period of time. Examples of Al alloys include magnesium-aluminum alloy (MgAl) and lithium-aluminum alloy (LiAl). Other alloys include lithium-magnesium alloy and lithium-indium alloy. In this embodiment, the counter electrode 20 is a thin film of Ag.

[0058] <Sealing layer> The sealing layer 21 is made of a light-transmitting material and is formed on the counter electrode 20 .

[0059] The sealing layer 21 functions as a sealing layer that protects the light-emitting layer 17, the intermediate layer 18, etc. from moisture and the like. The interface between the counter electrode 20 and the sealing layer 21 may be paired with a light-reflecting surface at the interface with the hole injection layer 15 of the pixel electrode 13 to form a resonator structure. Examples of materials for the sealing layer 21 include silicon oxynitride (SiON) and silicon nitride (SiN). The sealing layer 21 may further contain a resin material such as an acrylic resin or a silicone resin.

[0060] (2.2) Configuration of Color Filter Substrate 40 As shown in FIG. 1, the color filter substrate 40 includes an upper substrate 41, a light-shielding film 42, and a color filter 43.

[0061] <Upper board> The upper substrate 41 is a light-transmitting substrate that supports the light-shielding film 42 and the color filter 43. The upper substrate 41 may also have a function of improving the rigidity of the organic EL display panel 100 and, together with the sealing layer 21, preventing the intrusion of moisture, air, etc. The upper substrate 41 may be, for example, a glass substrate, a quartz substrate, a plastic substrate, or the like.

[0062] <Light-shielding film> As shown in FIG. 1, the light-shielding film 42 has openings at positions facing each organic EL element 1, and blocks light from passing through the positions between two adjacent organic EL elements 1. The light-shielding film 42 is a black resin layer that blocks visible light of wavelengths corresponding to R, G, and B, and is made of, for example, a resin material containing a black pigment. Examples of resin materials that can be used include acrylic resins, polyimide resins, novolac resins, and phenolic resins. Examples of black pigments that can be used include carbon black pigments, titanium black pigments, and metal oxide pigments.

[0063] <Color filter> 1, the color filters 43 are provided in the openings of the light-shielding film 42 so as to face the respective organic EL elements 1. The color filters 43 are transparent layers used to transmit visible light of wavelengths corresponding to R, G, and B, and have the function of correcting the light emitted from the organic EL element 1(R) (color filter 43(R)), the light emitted from the organic EL element 1(G) (color filter 43(G)), and the light emitted from the organic EL element 1(B) (color filter 43(B)), respectively, to improve contrast and color purity. The color filters 43 are made of, for example, a resin material containing a dye.

[0064] The color filter 43(G) has a transmittance of 70% or more at the peak wavelength (near a wavelength of 520 nm) amplified in the resonator structure of the organic EL element 1(G). Furthermore, within the wavelength range of 545 nm to 565 nm, there exists a wavelength at which the transmittance is 50% or less. That is, the wavelength at which the transmittance is 50% or less is a wavelength selected from the wavelength range of 545 nm to 565 nm, and may be, for example, 565 nm, 555 nm, or 545 nm. Details will be described later.

[0065] (2.3) Bonding layer The bonding layer 50 is a bonding layer for bonding the light emitting element substrate 30 and the color filter substrate 40 so that they face each other, and also has the function of protecting the light emitting element substrate 30 and the color filter substrate 40 from moisture and air. The bonding layer 50 is made of a light-transmitting resin material such as an acrylic resin, a silicone resin, or an epoxy resin.

[0066] 3. Structure to suppress external light reflection (3.1) Optical resonator structure 2 is a diagram illustrating optical interference in the optical resonator structure of the organic EL element 1 according to the present embodiment. The optical resonator structure is formed between the surface of the pixel electrode 13 facing the hole injection layer 15 and the surface of the counter electrode 20 facing the electron injection transport layer 19. A second optical resonator structure is formed between the surface of the pixel electrode 13 facing the hole injection layer 15 and the surface of the second optical adjustment layer 212 facing the first optical adjustment layer 211. The light-emitting layer 17 is located inside both the first and second resonator structures.

[0067] 2 shows the main paths of light emitted from the light-emitting layer 17. Path C1 is the path from the light-emitting layer Path C1 is a path through which light emitted from 17 to the counter electrode 20 side passes through the counter electrode 20 without being reflected. Path C2 is a path through which light emitted from the light-emitting layer 17 to the counter electrode 20 side is reflected by the surface of the counter electrode 20 on the electron injection transport layer 19 side, and further reflected by the surface of the pixel electrode 13 on the hole injection layer 15 side, and passes through the light-emitting layer 17 and the counter electrode 20. In the resonator structure, interference occurs between the light emitted via path C1 and the light emitted via path C2, resulting in light being emitted from the light-emitting element 1.

[0068] The difference in optical distance between the path C1 and the path C2 is the sum of the optical thickness L0 and the optical thickness L1 shown in FIG. 1t Here, the optical thickness is the value obtained by integrating the refractive index of the film with the film thickness, and more specifically, the optical thickness L 1t is the sum of the refractive index of the hole injection layer 15 × the film thickness of the hole injection layer 15, the refractive index of the hole transport layer 16 × the film thickness of the hole transport layer 16, the refractive index of the light emitting layer 17 × the film thickness of the light emitting layer 17, the refractive index of the intermediate layer 18 × the film thickness of the intermediate layer 18, and the refractive index of the electron injection transport layer 19 × the film thickness of the electron injection transport layer 19. Similarly, the difference in optical distance between the path C1 and the path C3 is the sum of the optical film thickness L0 and the optical film thickness L2 shown in FIG. 2t Corresponds to.

[0069] In the resonator structure, the optical film thickness L is set so that the light emitted through the path C1 and the light emitted through the path C2 are reinforced. 1t Set.

[0070] In the organic EL element 1(G), for example, the optical film thickness L 1t Similarly, the optical film thickness L is set so that the light of the desired wavelength is reinforced in each of the organic EL element 1(R) and the organic EL element 1(B). 1t This resonator structure can be said to be a filter with improved transmittance of light of a desired wavelength, and therefore functions as a filter with high transmittance of light of a desired wavelength with respect to external light, i.e., low reflectance of light of a desired wavelength.

[0071] (3.2) External light reflection and luminosity characteristics FIG. 3(a) is a graph showing the emission spectrum of the organic EL element 1 (G) and the transmission spectrum of the comparative (conventional) color filter (G).

[0072] The emission spectrum of the organic EL element 1 (G), which has a resonator structure to enhance the peak wavelength, has a characteristic with a peak around a wavelength of 520 nm (approximately 520 to 530 nm), as shown in emission spectrum 101 in Fig. 3(a). In contrast, the transmission spectrum 102 of the color filter (G) of the comparative example is designed to block the transmission of light with wavelengths shorter than around 460 nm and light with wavelengths longer than around 650 nm, in order to enhance color purity.

[0073] Meanwhile, the Y value profile in the CIE color matching function, which indicates the human visual sensitivity characteristics, particularly the sensitivity of M cone cells, reaches a maximum near a wavelength of 555 nm, as shown in Figure 3(b). Because the peak wavelength of G, which has high color purity, is approximately 520 to 530 nm, reflected light with a wavelength of 540 nm or more, particularly reflected light with a wavelength near 555 nm, causes a decrease in the color purity of the sub-pixel. Here, the intensity Y of the reflected light is expressed as follows using the intensity I of light from the incident light source, the aperture ratio A of the sub-pixel, and the reflectance R of the sub-pixel:

[0074] Y=I×A×R …(Equation 1) Here, the intensity I of light from the incident light source does not depend on the structure of the display panel, and reducing the aperture ratio A of the subpixel 2 increases the current density to the organic EL element 1, adversely affecting the element's lifespan. Therefore, in order to suppress external light reflection without reducing the luminous efficiency of the organic EL element 1, it is preferable to reduce the reflectance R of the subpixel for wavelengths at which external light reflection is desired to be suppressed.

[0075] The reflectance R of a sub-pixel of the display panel is expressed as T F , the optical reflectance of the organic EL element having the resonator structure is R A Then, it can be shown as follows:

[0076] R=R A ×T F 2 …(Formula 2) As mentioned above, the resonator structure is designed to have an emission peak at a wavelength of around 520 nm, so the reflectance R A As shown in FIG. 3(c), the reflectance in the vicinity of 520 to 530 nm is low. Therefore, assuming that the incident light source is light source C, as shown in FIG. 4(a), the reflected light spectrum 115 without a color filter is represented by the product of the incident light spectrum 113 and the reflectance spectrum 114, and peaks at wavelengths of approximately 550 to 570 nm. As shown in FIG. 3(b), light with wavelengths of approximately 550 to 570 nm has higher luminosity than light with wavelengths of approximately 520 nm, so reflected light with wavelengths of approximately 550 to 570 nm reduces the color purity of subpixel 2(G). In other words, without a color filter, when external light is incident on subpixel 2(G) in the emitting state, the color purity of subpixel 2(G) reduces.

[0077] (3.3) Color filter characteristics The following describes the spectrum of reflected light when a color filter is present, comparing color filters according to an embodiment of the present disclosure (Examples 1 and 2) with a conventional color filter (Comparative Example).

[0078] 4(b) shows the transmission spectra of the color filters of Examples 1 and 2 and the comparative example. In all color filters, the transmittance at the extraction wavelength (near 520 nm to 530 nm) of the resonator structure of the organic EL element 1 (G) is approximately 90%. Meanwhile, the transmittance at around 565 nm, which is the peak wavelength of the Y value in the CIE color matching function, is 63% for spectrum 121 of the comparative example, 50% for spectrum 122 of Example 1, and 34% for spectrum 123 of Example 2. As described above, the reflected light passes through the color filter twice in its propagation path. Therefore, the reflection spectrum when the color filter is present is calculated by multiplying reflection spectrum 115 when the color filter is not present by the square of the transmittance of the color filter, as shown in Equation 2.

[0079] FIG. 5(a) shows the reflection spectra of reflected light, with the Comparative Example corresponding to spectrum 131, Example 1 corresponding to spectrum 132, and Example 2 corresponding to spectrum 133. As mentioned above, spectrum 113 represents the Y color-matching function in the CIE color-matching functions, and spectrum 115 represents the reflected light when no color filter is present. As shown in FIG. 5(a), Comparative Example 131 exhibits two peaks: one near 520 nm, which is the extraction wavelength of the resonator of organic EL element 1 (G), and the other near 555 nm, which is the peak wavelength of the Y value in the CIE color-matching function. That is, light with peak wavelengths between 550 and 570 nm is included in the reflected light, and the color purity of subpixel 2 (G) is reduced by the reflected light. On the other hand, in Examples 1 (132) and 2 (133), a peak is present near 520 nm, which is the extraction wavelength of the resonator of organic EL element 1 (G), but no peak is observed near 555 nm, which is the peak wavelength of the Y value in the CIE color-matching function. That is, the component of the reflected light with a wavelength of 550 to 570 nm can be suppressed, thereby preventing a situation in which the color purity of the sub-pixel 2 (G) is reduced due to the reflected light. Note that, in order to sufficiently increase the luminance of the sub-pixel 2 (G), it is preferable that the transmittance of the color filter be at least 70% in the vicinity of 520 nm, which is the extraction wavelength of the resonator of the organic EL element 1 (G).

[0080] (3.4) Relationship between reflectance and aperture ratio FIG. 5(b) shows the relationship between the reflectance of color filter 43(G) and the optical reflectance of subpixel 2(G). As shown in FIG. 5(b), when the transmittance of light with a wavelength of 565 nm through color filter 43(G) is 50%, the optical reflectance of subpixel 2(G) is approximately 17%. Assuming that the reflectances of the other subpixels 2(R) and 2(B) are similar, if the aperture ratio of subpixel 2(G) is 50%, the reflectance of the organic EL display panel 100 is 3%. Considering the quality of the display panel, a reflectance of 3% or less provides sufficient image quality. Therefore, if the aperture ratio is 50%, the transmittance of light with a wavelength of 565 nm through color filter 43(G) is preferably 50% or less. Note that when the aperture ratio of the subpixel is 80%, the reflectance of subpixel 2(G) needs to be approximately 12% or less, so the transmittance of light with a wavelength of 565 nm through color filter 43(G) is preferably 24% or less.

[0081] 4.Summary As described above, in a display panel according to one embodiment of the present disclosure, the resonator structure formed between the pixel electrode and the counter electrode in a green light-emitting element improves the light extraction efficiency of a desired wavelength, thereby simultaneously improving both the emission intensity and color purity. Furthermore, the color filter (G) is configured to have wavelengths in the 545 nm to 565 nm wavelength range at which the transmittance is 50% or less. That is, by setting the transmittance of light near a wavelength of 555 nm in the color filter (G) to 50% or less, the reflectance of light near a wavelength of 555 nm is sufficiently reduced, thereby preventing a decrease in color purity due to reflected light. Therefore, the light extraction efficiency is improved and the driving voltage is reduced, thereby improving the efficiency and lifespan of the light-emitting element, and color purity is also improved. Furthermore, because the reflectance can be reduced without a black matrix, the aperture ratio is easily improved, and the driving voltage is reduced, thereby further improving the efficiency and lifespan of the light-emitting element.

[0082] 5. Display panel manufacturing method The manufacturing method of the display panel will be described with reference to the drawings. Fig. 6 is a flowchart showing the manufacturing process of the display panel. Figs. 7(a) to (e), 8(a) to (d), 9(a) to (d), and 10(a) to (d) are schematic cross-sectional views showing the state of each process in the manufacturing of the display panel.

[0083] (1) Preparation of Substrate 11 7(a), a TFT layer 112 is formed on a base material 111 to form a substrate 11 (step S10). The TFT layer 112 can be formed by a known TFT manufacturing method.

[0084] (2) Formation of the interlayer insulating layer 12 7(b), an interlayer insulating layer 12 is formed on the substrate 11 (step S20). The interlayer insulating layer 12 can be formed by laminating layers using, for example, a plasma CVD method, a sputtering method, or the like.

[0085] Next, a contact hole is formed by dry etching at a location above the source electrode of the TFT layer in the interlayer insulating layer 12. The contact hole is formed so that the surface of the source electrode is exposed at the bottom thereof.

[0086] Next, a connection electrode layer is formed along the inner wall of the contact hole. A portion of the upper part of the connection electrode layer is disposed on the interlayer insulating layer 12. The connection electrode layer can be formed by, for example, sputtering, and after depositing a metal film, it is patterned by photolithography and wet etching.

[0087] (3) Formation of pixel electrode 13 7(c), a pixel electrode material layer 130 is formed on the interlayer insulating layer 12. The pixel electrode material layer 130 can be formed by using, for example, a vacuum deposition method, a sputtering method, or the like.

[0088] Next, as shown in FIG. 7(d), the pixel electrode material layer 130 is patterned by etching to form a plurality of pixel electrodes 13 partitioned into sub-pixels (step S30).

[0089] (4) Formation of partition wall 14 Next, as shown in FIG. 7(e), a partition layer resin, which is a material for the partition walls 14, is applied onto the pixel electrodes 13 and the interlayer insulating layer 12 to form a partition wall material layer 140. The partition wall material layer 140 is formed by uniformly applying a solution of a phenolic resin, which is the partition wall resin, dissolved in a solvent (e.g., a mixed solvent of ethyl lactate and GBL), onto the pixel electrodes 13 and the interlayer insulating layer 12 using a method such as spin coating. The partition wall material layer 140 is then subjected to pattern exposure and development to form the partition walls 14 (FIG. 8(a)), and the partition walls 14 are then baked (step S40). This defines openings 14a where the light-emitting layers 17 will be formed. The partition walls 14 are baked, for example, at a temperature of 150°C to 210°C for 60 minutes.

[0090] Furthermore, in the process of forming the partition walls 14, the surfaces of the partition walls 14 may be further treated with a predetermined alkaline solution, water, an organic solvent, or the like, or may be subjected to plasma treatment. This is performed for the purpose of adjusting the contact angle of the partition walls 14 with respect to the ink (solution) to be applied to the openings 14a, or for the purpose of imparting water repellency to the surfaces.

[0091] (5) Formation of the hole injection layer 15 Next, as shown in FIG. 8(b), ink containing a constituent material of the hole injection layer 15 is ejected from the nozzle 401 of the inkjet head 410 into the opening 14a defined by the partition 14, and applied onto the pixel electrode 13 in the opening 14a, followed by baking (drying) to form the hole injection layer 15 (step S50).

[0092] The hole injection layer 15 may be formed by other methods such as vapor deposition, without being limited to coating. Furthermore, when the hole injection layer 15 is formed by vapor deposition or sputtering, after the pixel electrode material layer 130 is formed in step 30, a hole injection material layer made of the material of the hole injection layer 15 may be formed on the pixel electrode material layer 130, and the pixel electrode material layer 130 and the hole injection material layer may be patterned in the same patterning step to form a laminated structure of the pixel electrode 13 and the hole injection layer 15.

[0093] (6) Formation of the hole transport layer 16 Next, as shown in FIG. 8(c), ink containing a constituent material of the hole transport layer 16 is ejected from the nozzle 402 of the inkjet head 420 into the opening 14a defined by the partition 14 to apply it onto the hole injection layer 15 in the opening 14a, and then baked (dried) to form the hole transport layer 16 (step S60).

[0094] The hole transport layer 16 may be formed by other methods such as vapor deposition, without being limited to coating. Furthermore, when the pixel electrode 13, the hole injection layer 15, and the hole transport layer 16 are all formed by vapor deposition or sputtering, each layer may be patterned in the same patterning step, as described above.

[0095] (7) Formation of the light-emitting layer 17 Next, as shown in FIG. 8(d), ink containing the constituent material of the light-emitting layer 17 is ejected from each of the nozzles 403R of the inkjet head 430R, the nozzles 403G of the inkjet head 430G, and the nozzles 403B of the inkjet head 430B to be applied onto the hole transport layer 16 in the opening 14a, and then baked (dried) to form the light-emitting layer 17 (step S70).

[0096] (8) Formation of intermediate layer 18 9(a), the intermediate layer 18 is formed on the light-emitting layer 17 and the partition wall 14 (step S80). The intermediate layer 18 is formed by, for example, forming a film of NaF, which is an alkali metal fluoride, by vacuum deposition in common to each sub-pixel.

[0097] (9) Formation of the electron injection transport layer 19 9(b), the electron injection transport layer 19 is formed on the intermediate layer 18 (step S90). The electron injection transport layer 19 is formed, for example, by co-evaporating an electron-transporting organic material and ytterbium, which is a doped metal, to form a film common to all sub-pixels.

[0098] (10) Formation of the counter electrode 20 9(c), the counter electrode 20 is formed on the electron injecting and transporting layer 19 (step S100). The counter electrode 20 is formed by depositing a metal material such as Ag or Al by sputtering or vacuum deposition.

[0099] (11) Formation of sealing layer 21 9(d), the sealing layer 21 is formed (step S110). The sealing layer 21 can be formed using, for example, SiON or SiN by sputtering or CVD.

[0100] Upon completion of this step, the light emitting element substrate 30 is completed.

[0101] (12) Formation of the light-shielding film 42 10(a), a material for the light-shielding film 42 is applied onto the upper substrate 41 to form the light-shielding material film 42. Then, the light-shielding material film 42 is subjected to pattern exposure and development to form the light-shielding film 42, and is baked (FIG. 10(b), step S120).

[0102] (13) Formation of color filter 43 10(c), the gaps in the light-shielding film 42 are coated with the material of the color filters 43 and baked to form the color filters 43. The method of forming the color filters 43 is not limited to the coating method, and for example, the color filters 43 may be formed by forming a color filter material layer as a solid film and then performing pattern exposure and development.

[0103] (14) Attaching the board Finally, as shown in FIG. 10(d), the material of the bonding layer 50 is applied onto the sealing layer 21 of the light emitting element substrate 30, and the upper substrate is attached.

[0104] 6. Overall configuration of the display device 11 is a schematic block diagram showing the configuration of a display device 1000 equipped with a display panel 100. As shown in Fig. 11, the display device 1000 includes the display panel 100 and a drive control unit 200 connected thereto. The drive control unit 200 is made up of four drive circuits 210 to 240 and a control circuit 250.

[0105] In an actual display device 1000, the arrangement of the drive control unit 200 relative to the display panel 100 is not limited to this.

[0106] Other Modifications of the Embodiment (1) In the above embodiment, the organic EL element 1, which is a light-emitting element, includes the hole injection layer 15, the hole transport layer 16, the intermediate layer 18, and the electron injection transport layer 19. However, this configuration is not necessarily required. One or more of these layers may be omitted, or other functional layers may be included. For example, the intermediate layer 18 may be omitted, or an electron transport layer may be included instead of the intermediate layer 18 or between the intermediate layer 18 and the light-emitting layer 17.

[0107] Furthermore, the manufacturing method of each functional layer is merely an example. For example, the light-emitting layer 17 may be formed by a vapor deposition method, and the color filter 43 may be formed by a printing method.

[0108] (2) In the above embodiment, the display panel includes three types of light-emitting elements that emit R, G, and B light, respectively. However, at least one type of light-emitting element may be a green light-emitting element, and the other types of light-emitting elements may be one type or three or more types. Here, the type of light-emitting element refers to variations in each element that constitutes the light-emitting element. Even if the light-emitting color is the same, light-emitting elements with different film thicknesses of the light-emitting layer or functional layer can be considered to be different types. Furthermore, the arrangement of the light-emitting elements is not limited to an RGBRGB... arrangement, but may be an RGBBGRRGB... arrangement, and auxiliary electrode layers or other non-light-emitting regions may be provided between the light-emitting elements.

[0109] In addition, in the embodiment, the intermediate layer 18, the electron injecting and transporting layer 19, and the counter electrode 20 are formed as a common film, but the film thickness may be different for each light-emitting element.

[0110] (3) In the embodiment, the interface between the pixel electrode 13 and the hole injection layer 15 and the interface between the counter electrode 20 and the electron injection transport layer 19 in the organic EL element 1 constitute an optical resonator structure. However, the surface of the optical resonator structure on the color filter 43 side is not limited to the interface between the counter electrode 20 and the electron injection transport layer 19, and may be, for example, the interface between the counter electrode 20 and the sealing layer 21. Alternatively, for example, an optical adjustment layer may be provided between the counter electrode 20 and the sealing layer 21, and the interface may be the interface between the counter electrode 20 and the optical adjustment layer, or a plurality of optical adjustment layers may be provided, and the interface may be between two adjacent optical adjustment layers.

[0111] (4) In the embodiment, the transmission characteristics of the color filter 43(G) are set so that the transmittance of light having a wavelength of around 555 nm (light having a wavelength selected from the wavelength range of 545 nm to 565 nm) is 50% or less. However, the subpixel 2 may include three elements: an organic EL element 1(G), a conventional color filter, and a reflection-reducing filter having a transmittance of around 555 nm of 50% or less. In this case, the reflection-reducing filter may be, for example, an edge filter that blocks light having a wavelength of 555 nm or more. The reflection-reducing filter may be provided, for example, by being stacked on the color filter 43(G) on the color filter substrate 40, or may be provided on the counter electrode 20 of the organic EL element 1(G) on the light-emitting element substrate 30.

[0112] (5) In the embodiment, the pixel electrode is an anode and the counter electrode is a cathode, but the pixel electrode may be a cathode and the counter electrode may be an anode.

[0113] (6) While the display panel and display device according to the present disclosure have been described above based on the embodiments and modifications, the present invention is not limited to the above-described embodiments and modifications. The present invention also includes forms obtained by applying various modifications to the above-described embodiments and modifications that would occur to a person skilled in the art, and forms realized by arbitrarily combining the components and functions of the embodiments and modifications within the scope of the present invention. [Industrial Applicability]

[0114] The present invention is useful for manufacturing a display panel using a light-emitting element having an optical resonator structure, which has an improved aperture ratio while suppressing a decrease in color purity due to external light reflection, and has high color purity and luminous efficiency. [Explanation of symbols]

[0115] 100 Organic EL display panel 1. Organic EL element 2 subpixels 11 Circuit Board 12 Interlayer insulation layer 13 Pixel electrode 14 Bulkhead 15 Hole injection layer 16 Hole transport layer 17 Light-emitting layer 18 Middle Class 19 Electron injection transport layer 20 Counter electrode 21 Sealing layer 30 Light emitting element substrate 40 Color filter substrate 41 Upper board 42 Light-shielding film 43 Color Filter

Claims

1. A display panel including a plurality of pixels, each pixel including a self-luminous element and a color filter facing the self-luminous element, At least one of the plurality of self-luminous elements is a green light-emitting element, the green light emitting element has an optical resonator structure in which a light-transmitting thin-film metal electrode, a green light emitting layer, and a light-reflective electrode are stacked in that order from the side closest to the color filter, thereby enhancing the light intensity of a first wavelength; the aperture ratio of the pixel including the green light emitting element is 50% or more; a color filter facing the green light-emitting element included in the pixel having an aperture ratio of 50% or more has a light transmittance of 50% or less for light of a second wavelength of 565 nm, which is longer than the first wavelength and has a higher visibility characteristic as green than the first wavelength; In the pixel including the green light emitting element, when the aperture ratio is 50% and the light reflectance of light with a wavelength of 565 nm is 17%, the transmittance of the color filter is 50% or less, or In the pixel including the green light emitting element, when the aperture ratio is 80% and the light reflectance of light with a wavelength of 565 nm is 12%, the transmittance of the color filter is 24% or less. Display panel.

2. In the CIE color matching functions, the Y value corresponding to the second wavelength is greater than the Y value corresponding to the first wavelength. The display panel according to claim 1 .

3. The first wavelength is 530 nm or less.

3. The display panel according to claim 1.

4. The color filter facing the self-luminous element has a transmittance of 70% or more for light at the first wavelength. The display panel according to claim 1 .

5. A display panel including a plurality of pixels, each pixel including a self-luminous element and a color filter facing the self-luminous element, At least one of the plurality of self-luminous elements is a green light-emitting element, the green light emitting element has an optical resonator structure in which a light-transmitting thin-film metal electrode, a green light emitting layer, and a light-reflective electrode are stacked in that order from the side closest to the color filter, thereby enhancing the light intensity of a first wavelength; the aperture ratio of the pixel including the green light emitting element is 50% or more; The pixel including the green light emitting element and having an aperture ratio of 50% or more further includes a second filter having a light transmittance of 50% or less for light of a second wavelength of 565 nm, which is longer than the first wavelength and has a higher visibility characteristic as green than the first wavelength, the first wavelength is 520 to 530 nm; The second filter is an edge filter that blocks light having a wavelength of 555 nm or more, and is laminated on the color filter. Display panel.

6. A display device comprising the display panel according to claim 1 .

7. forming a plurality of light-reflective electrodes on a substrate; forming a light-emitting layer above each of the plurality of light-reflective electrodes; forming a light-transmitting metal thin film electrode above the plurality of light-emitting layers to form an optical resonator structure; forming a color filter above the metal thin film electrode and above each of the plurality of light-emitting layers; In forming the light-emitting layers, at least one light-emitting layer is a green light-emitting layer, the aperture ratio of a pixel including the green light-emitting element and the corresponding color filter is 50% or more; In forming the color filter, when a peak wavelength of the optical resonator structure is defined as a first wavelength, a transmission characteristic of the color filter above the green light-emitting layer included in the pixel having an aperture ratio of 50% or more is set to a light transmittance of 50% or less for light having a second wavelength of 565 nm, which is longer than the first wavelength and has a higher visibility characteristic as green than the first wavelength; For the pixel including the green light emitting element, the color filter is formed to have a transmittance of 50% or less when the aperture ratio is 50% and the light reflectance of light with a wavelength of 565 nm is 17%, or For the pixel including the green light emitting element, when the aperture ratio is 80% and the light reflectance of light with a wavelength of 565 nm is 12%, the color filter is formed with a transmittance of 24% or less. A method for manufacturing a display panel.

Images