Display device and manufacturing method thereof

Abstract

Provided is a display device in which, in at least one sub-pixel (SP), a light emitting layer includes: a first region (431); and a second region (432) in which the number of inorganic ligands contained per unit volume thereof is less than the number of inorganic ligands contained per unit volume of the first region. The first region includes the center section of the light emitting layer. In the light emitting layer, the second region includes at least one edge section from among edge sections adjacent to other adjacent sub-pixels.

Description

[Technical field]

[0001] The present disclosure relates to a display device and a manufacturing method thereof. [Background technology]

[0002] A ligand is generally provided on the surface of a quantum dot for the purpose of protecting the quantum dot and improving dispersibility in a solvent. An organic ligand is generally used as the ligand. Meanwhile, inorganic ligands have been attracting attention in recent years as an alternative to organic ligands.

[0003] Inorganic ligands are more stable than organic ligands and have excellent current injection properties. For example, Patent Document 1 discloses a stable nanostructure composition that includes a nanostructure and a specific fluoride-containing ligand or fluoride anion as an inorganic ligand. Patent Document 1 also cites quantum dots as an example of the nanostructure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-180278 Summary of the Invention [Problem to be solved by the invention]

[0005] However, quantum dots containing inorganic ligands such as halogen ligands containing fluoride emit light even with a small leakage current. Therefore, in a display device having an emission layer formed with such quantum dots, when one subpixel emits light, the leakage current from the subpixel causes the adjacent subpixel to emit light, resulting in optical crosstalk such as color mixing and the formation of a blurred image. Such crosstalk causes a decrease in the display quality of the display device.

[0006] One aspect of the present disclosure has been made in consideration of the above problems, and an object of the present disclosure is to provide a display device and a manufacturing method thereof that can achieve both improved luminous efficiency, stability, and current injection properties by inorganic ligands, and suppression of luminescence due to leakage current from adjacent sub-pixels. [Means for solving the problem]

[0007] In order to solve the above problem, according to one aspect of the present disclosure, a display device includes a plurality of subpixels, each of the plurality of subpixels including a first electrode, a second electrode, and a functional layer including at least a light-emitting layer disposed between the first electrode and the second electrode, the light-emitting layer of at least one of the plurality of subpixels including a first region including quantum dots and at least the inorganic ligand of an organic ligand and an inorganic ligand, and a second region including the quantum dots and at least the organic ligand of the organic ligand and the inorganic ligand, the number of the inorganic ligands included per unit volume being smaller than the number of the inorganic ligands included per unit volume of the first region, the first region including a central portion of the light-emitting layer of the at least one subpixel, and the second region including at least one end of the light-emitting layer of the at least one subpixel adjacent to another subpixel adjacent to the at least one subpixel.

[0008] In order to solve the above-mentioned problems, according to one aspect of the present disclosure, there is provided a method for manufacturing a display device comprising a plurality of sub-pixels, each of the plurality of sub-pixels comprising a first electrode, a second electrode, and a functional layer including at least a light-emitting layer provided between the first electrode and the second electrode, the method including a first electrode forming step of forming the first electrode, a functional layer forming step of forming the functional layer, and a second electrode forming step of forming the second electrode, the functional layer forming step including a light-emitting layer forming step of forming the light-emitting layer, and in the light-emitting layer forming step, a quantum dot and an organic ligand are formed as the light-emitting layer in at least one sub-pixel of the plurality of sub-pixels. and at least the inorganic ligand among the inorganic ligands; and a second region including the quantum dots, the organic ligands and at least the organic ligand among the inorganic ligands, wherein the number of the inorganic ligands contained per unit volume is smaller than the number of the inorganic ligands contained per unit volume of the first region, wherein the first region includes a central portion of the light-emitting layer of the at least one sub-pixel, and the second region forms a light-emitting layer including at least one end portion of the light-emitting layer of the at least one sub-pixel that is adjacent to other sub-pixels adjacent to the at least one sub-pixel. Effect of the Invention

[0009] According to one aspect of the present disclosure, there is provided a display device that can achieve both improved luminous efficiency by an inorganic ligand and suppression of luminescence caused by leakage current from adjacent sub-pixels, and a manufacturing method thereof. [Brief description of the drawings]

[0010] [Figure 1] 1 is a plan view showing an example of a schematic configuration of a main part of a display device according to a first embodiment. [Diagram 2] 1 is a plan view showing an example of a schematic configuration of a sub-pixel in a pixel region of the display device according to Embodiment 1. FIG. [Diagram 3] 1 is a cross-sectional view showing an example of a schematic configuration of a main part of a display device according to a first embodiment. [Figure 4] 2 is a schematic enlarged cross-sectional view showing a part of a light-emitting layer of each color in an example of a display device according to embodiment 1. FIG. [Diagram 5] 13 is a cross-sectional view illustrating a leakage current between a first sub-pixel and a second sub-pixel of a comparative display device. FIG. [Figure 6] 6 is a circuit diagram illustrating a leakage current between a first sub-pixel and a second sub-pixel in the comparative display device shown in FIG. 5. FIG. [Figure 7] 5 is a flowchart showing an example of a manufacturing method of the display device according to the first embodiment. [Figure 8] 8 is a flowchart showing an example of a functional layer forming step shown in FIG. 7. [Figure 9] 9 is a flow chart showing an example of a light emitting layer forming step shown in FIG. [Figure 10] 10 is a cross-sectional view showing an example of a part of the step of forming a first light-emitting layer shown in FIG. [Figure 11] 11 is a partially enlarged cross-sectional view typically showing a step subsequent to FIG. 10 in the step of forming the first light-emitting layer shown in FIG. 9. FIG. [Figure 12] 10 is a cross-sectional view showing an example of a part of the step of forming a second light-emitting layer shown in FIG. [Figure 13] 13 is a partially enlarged cross-sectional view typically showing a step subsequent to FIG. 12 in the second light-emitting layer forming step shown in FIG. 9. FIG. [Figure 14] 10 is a cross-sectional view showing an example of a part of the step of forming a third light-emitting layer shown in FIG. [Figure 15] 15 is a partially enlarged cross-sectional view typically showing a step subsequent to FIG. 14 in the third light-emitting layer forming step shown in FIG. 9. FIG. [Figure 16] 10 is a cross-sectional view showing another example of a part of the step of forming a third light-emitting layer according to a modified example of Embodiment 1. FIG. [Figure 17] 5A to 5C are cross-sectional views showing an example of a part of a process for forming a light-emitting layer according to embodiment 2. [Figure 18] 18 is a cross-sectional view showing a step subsequent to that shown in FIG. 17 in the step of forming a light-emitting layer according to the second embodiment. [Figure 19]19 is a partially enlarged cross-sectional view that illustrates a schematic diagram of a step subsequent to that of FIG. 18 in a light-emitting layer forming step according to Embodiment 2. FIG. [Figure 20] 10 is a partially enlarged cross-sectional view illustrating a schematic diagram of a light-emitting layer forming step according to Modification 2 of Embodiment 2. FIG. [Figure 21] 11 is a partially enlarged cross-sectional view illustrating a schematic diagram of a light-emitting layer forming step according to Modification 3 of Embodiment 2. FIG. [Figure 22] 13 is a flowchart showing an example of a light emitting layer forming step according to Modification 4 of Embodiment 2. [Figure 23] FIG. 11 is a plan view showing an example of a schematic configuration of a sub-pixel in a pixel region of a display device according to Embodiment 3. [Figure 24] FIG. 11 is a plan view showing an example of a schematic configuration of a sub-pixel in a pixel region of a display device according to Embodiment 4. [Diagram 25] FIG. 13 is a plan view showing an example of a schematic configuration of a sub-pixel in a pixel region of a display device according to Embodiment 5. [Figure 26] FIG. 13 is a plan view showing an example of a schematic configuration of a sub-pixel in a pixel region of a display device according to Embodiment 6. [Figure 27] 11 is a graph showing the relationship between the distance from an edge of a subpixel, the amount of voltage rise of the subpixel due to driving of a subpixel adjacent to the subpixel, and the amount of rise in the emission threshold voltage of the subpixel. [Figure 28] 13 is a cross-sectional view showing an example of a schematic configuration of a main part of a display device according to embodiment 7. FIG. [Figure 29] 13 is a cross-sectional view showing an example of a part of a process for forming a light-emitting layer according to embodiment 8. FIG. [Diagram 30] 13 is a cross-sectional view showing another example of a part of the process of forming a light-emitting layer according to embodiment 8. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The embodiments of the present disclosure will be described in detail below. In each of the following embodiments, the same reference numerals are used for components having the same functions as those previously described, and the description will not be repeated. In addition, in the second and subsequent embodiments, differences from the previously described embodiments will be described. It goes without saying that, even if there is no particular explanation, the second and subsequent embodiments can be modified in the same manner as the previously described embodiments. In addition, hereinafter, the description "A to B" for two numbers A and B means "greater than or equal to A and less than or equal to B" unless otherwise specified.

[0012] [Embodiment 1] FIG. 1 is a plan view showing an example of a schematic configuration of a main part of a display device 1 according to the present embodiment.

[0013] As shown in FIG. 1, the display device 1 includes a pixel region DA in which a plurality of pixels P, each having a plurality of sub-pixels SP, are provided, and a frame region NDA that is provided around the pixel region DA so as to surround the pixel region DA.

[0014] The frame area NDA is provided with a terminal unit TS to which signals for driving each sub-pixel SP are input. The terminal unit TS may be provided with an electronic circuit board (not shown), such as an IC (integrated circuit) chip or an FPC (flexible printed circuit board).

[0015] In the pixel area DA, for example, a plurality of wirings including a plurality of gate wirings GH, a plurality of light emission control lines EM, and a plurality of initialization potential lines IL are arranged to extend in the row direction. In the display section DA, for example, a plurality of wirings including a plurality of power supply lines PL and a plurality of source wirings SH are arranged to extend in the column direction. A plurality of sub-pixels SP are arranged, for example, in a matrix shape, so as to correspond to the intersections of the gate wirings GH and the source wirings SH.

[0016] Fig. 2 is a plan view showing an example of a schematic configuration of a sub-pixel SP in the pixel region DA of the display device 1 shown in Fig. 1. Note that, for convenience of illustration, the number of sub-pixels SP is omitted in Fig. 2.

[0017] 1 and 2, the display device 1 includes sub-pixels SP emitting different light colors as the sub-pixels SP. Specifically, the display device 1 includes, as the sub-pixels SP, a red sub-pixel RSP (red sub-pixel), a green sub-pixel GSP (green sub-pixel), and a blue sub-pixel BSP (blue sub-pixel), for example.

[0018] The sub-pixel RSP emits red (R), the sub-pixel GSP emits green (G), and the sub-pixel BSP emits blue (B). In this embodiment, when there is no need to particularly distinguish between the sub-pixels RSP, GSP, and BSP, they are collectively referred to simply as "sub-pixels SP."

[0019] The sub-pixels SP provided in the pixel region DA may include a plurality of sub-pixels SP having the same emission color. In the following, as shown in FIG. 1 and FIG. 2, a case will be described as an example in which the display device 1 includes a plurality of pixels P each composed of a sub-pixel SP of three different colors, RGB, and the plurality of pixels P are provided in a matrix in the pixel region DA. In the following, as shown in FIG. 1 and FIG. 2, a case will be described as an example in which the sub-pixels SP of each color, RGB, are repeatedly arranged in this order in the extending direction of the gate wiring GH, and a plurality of sub-pixels SP are arranged for each color along the extending direction of the source wiring SH. However, the above example is merely an example, and the display device 1 may include sub-pixels SP other than RGB. In addition, the arrangement of the sub-pixels SP is not limited to the above arrangement. In the following, a case will be described as an example in which all the sub-pixels SP are formed in a rectangular shape. However, the above shape is merely an example, and the shape (outer shape) of the sub-pixels SP is not limited to the above shape.

[0020] 3 is a cross-sectional view showing an example of a schematic configuration of a main part of the display device 1 according to this embodiment. Note that Fig. 3 corresponds to the cross section taken along line AA' shown in Fig. 2.

[0021] 1, the display device 1 includes a substrate 2 and a light emitting element layer 3 in this order from the bottom. A sealing layer (not shown) may be provided above the light emitting element layer 3 to cover the light emitting element layer 3 and prevent the intrusion of foreign matter such as moisture, oxygen, and excess organic matter such as dust generated during the manufacturing process into the light emitting element layer 3. In addition, the upper layer of the sealing layer may include, as necessary, a functional film having at least one of an optical compensation function, a touch sensor function, and a protection function, a touch panel, a polarizing plate, or the like.

[0022] It should be noted that the term "lower layer" means that it is formed in an earlier process than the layer being compared, and the term "upper layer" means that it is formed in a later process than the layer being compared.

[0023] The substrate 2 is an array substrate. The substrate 2 has a structure in which a TFT (thin film transistor) layer is provided on a support substrate. The support substrate is a support that supports each layer provided on the support substrate. An insulating substrate is used for the support substrate. The support substrate may be, for example, a non-flexible substrate made of an inorganic material such as glass, or a flexible substrate mainly composed of a resin. When the display device 1 is a top emission type display device, the support substrate used is not particularly limited. On the other hand, when the display device 1 is a bottom emission type display device, a transparent or semi-transparent light-transmitting substrate is used as the support substrate.

[0024] In the TFT layer, a subpixel circuit provided for each subpixel SP and a plurality of wirings including a gate wiring GH and a source wiring SH connected to the subpixel circuits are formed. The subpixel circuit includes a plurality of TFTs for driving a light-emitting element ES described later. The TFTs are electrically connected to a plurality of wirings including the gate wiring GH and the source wiring SH. Various known TFTs can be used as the TFTs. The TFTs and wirings are covered with a planarizing film that flattens the unevenness caused by the TFTs and wirings, and the surface of the TFT layer is planarized by the planarizing film. An organic insulating film such as an acrylic resin is used for the planarizing film.

[0025] The light-emitting element layer 3 includes a plurality of light-emitting elements ES provided for each sub-pixel SP, and has a structure in which each layer of these light-emitting elements ES is stacked on the substrate 2. The sub-pixel RSP includes a red light-emitting element RES (red light-emitting element) that emits red light as the light-emitting element ES. The sub-pixel GPG includes a green light-emitting element GES (green light-emitting element) that emits green light as the light-emitting element ES. The sub-pixel BSP includes a blue light-emitting element BES (blue light-emitting element) that emits blue light as the light-emitting element ES. In this embodiment, when there is no need to particularly distinguish between the light-emitting element RES, light-emitting element GES, and light-emitting element BES, they will be collectively referred to simply as "light-emitting element ES."

[0026] The light-emitting element layer 3 includes a plurality of patterned first electrodes, a second electrode, a functional layer including at least a light-emitting layer disposed between the first and second electrodes, and an insulating bank covering the edges of each first electrode.

[0027] The first electrode is a lower-layer electrode (subpixel electrode) provided in an island shape for each light-emitting element ES (in other words, for each subpixel SP) on the substrate 2. The second electrode is an upper-layer electrode (common electrode) provided in common to all the light-emitting elements ES (in other words, all the subpixels SP) above the lower-layer electrode, via the functional layer and the bank.

[0028] In this embodiment, the layers between the first electrode and the second electrode are collectively referred to as functional layers. The display device 1 may further include functional layers other than the light-emitting layer, such as a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer. In the following, the light-emitting layer may be referred to as "EML". The hole injection layer is referred to as "HIL", and the hole transport layer is referred to as "HTL". The electron injection layer is referred to as "EIL", and the electron transport layer is referred to as "ETL".

[0029] One of the first electrode and the second electrode is an anode 31, and the other is a cathode 34. The first electrodes are electrically connected to the TFTs of the substrate 2, respectively.

[0030] 3 illustrates an example in which the first electrode is an anode 31, the second electrode is a cathode 34, and the display device 1 includes an anode 31, a functional layer 33, and a cathode 34 in this order from the bottom in each subpixel SP. Also, FIG. 3 illustrates an example in which the functional layer 33 in each subpixel SP includes an HIL 41, an HTL 42, an EML 43, and an ETL 44 in this order from the bottom.

[0031] However, this embodiment is not limited to this. For example, the display device 1 may include a cathode 34, a functional layer 33, and an anode 31 in this order from the bottom in each subpixel SP. In this way, when the first electrode is the cathode 34 and the second electrode is the anode 31, the lamination order of the functional layer 33 is reversed from that in FIG. 3. In addition, the functional layer 33 may include functional layers other than the HIL 41, the HTL 42, the EML 43, and the ETL 44.

[0032] The anode 31 is made of a conductive material and is an electrode that supplies holes to the EML 43 when a voltage is applied thereto. The cathode 34 is made of a conductive material and is an electrode that supplies electrons to the EML 43 when a voltage is applied thereto.

[0033] Of the anode 31 and the cathode 34, the electrode that is to be the light extraction surface side must be light-transmitting. Therefore, at least one of the anode 31 and the cathode 34 has light-transmitting properties.

[0034] For example, when the display device 1 is a top-emission type display device that emits light from the sealing layer side, a translucent electrode is used for the upper cathode 34, and a so-called reflective electrode having light reflectivity is used for the lower anode 31. On the other hand, when the display device 1 is a bottom-emission type display device that emits light from the substrate 2 side, an opaque electrode or a reflective electrode is used for the upper cathode 34, and a translucent electrode is used for the lower anode 31.

[0035] The translucent electrode is formed of a conductive translucent material such as ITO (indium tin oxide), IZO (indium zinc oxide), AgNW (silver nanowire), a thin film of MgAg (magnesium-silver) alloy, or a thin film of Ag (silver).

[0036] On the other hand, the reflective electrode is formed of a conductive light-reflective material such as a metal such as Ag (silver), Al (aluminum), Cu (copper), or an alloy containing these metals. The reflective electrode may be formed by laminating the above-mentioned light-transmitting material and the above-mentioned light-reflective material.

[0037] The bank 32 is an insulating layer having visible light absorbing or light blocking properties. The bank 32 is used as an edge cover that covers the edge of the first electrode, and prevents the first electrode and the second electrode from being short-circuited due to the thinning of the functional layer 33 or the occurrence of electric field concentration at the pattern end of the first electrode. The bank 32 also functions as a subpixel separation film that separates each subpixel SP. The first electrode and at least the EML 43 of the functional layer 33 are separated (patterned) into an island shape for each subpixel SP by the bank 32. As a result, the light emitting element layer 3 is provided with light emitting elements ES including an anode 31, a functional layer 33, and a cathode 34, each corresponding to a subpixel SP.

[0038] The material of the bank 32 may be, for example, a photosensitive resin to which a light absorbing agent such as carbon black has been added. The photosensitive resin may be, for example, an organic insulating material having photosensitivity such as polyimide or acrylic resin.

[0039] The bank 32 has a tapered cross section in cross section. In other words, the bank 32 has an opening with an inverse tapered cross section, with the opening size (diameter) decreasing toward the bottom. If the angle (inclination angle) between the inclined surface of the bank 32 (in other words, the inclined opening sidewall) and the lower surface (bottom surface) of the bank 32 is θ (°), then θ is preferably 10°≦θ≦90°, and more preferably 30°≦θ≦80°. This makes it possible to reduce manufacturing defects in the bank 32 while preventing step breaks in the upper layer.

[0040] The HIL 41 is a layer that has a hole transport property and promotes the injection of holes from the anode 31 to the HTL 42 or the EML 43. A known hole transport material can be used for the HIL 41. Examples of the hole transport material used for the HIL 41 include a composite of poly(3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonic acid (PSS) (abbreviated as "PEDOT:PSS"), NiO (nickel oxide), and CuSCN (copper thiocyanate). Note that these hole transport materials may be used alone or in a suitable mixture of two or more types.

[0041] The HTL 42 is a layer that has a hole transport property and transports holes injected from the HIL 41 to the EML 43. A known hole transport material can be used for the HTL 42. Examples of hole transport materials used for the HTL 42 include 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 "p-TPD"), polyvinylcarbazole (abbreviated as "PVK"), and the like. These hole transport materials may be used alone or in a suitable mixture of two or more kinds.

[0042] The ETL 44 is a layer that has an electron transport property and transports electrons from the cathode 34 to the EML 43. A known electron transport material can be used for the ETL 44. Examples of the electron transport material used for the ETL 44 include ZnO (zinc oxide) and MgZnO (magnesium zinc oxide). These electron transport materials may be used alone or in a suitable mixture of two or more types.

[0043] The EML 43 is a layer that emits light when holes transported from the anode 31 and electrons transported from the cathode 34 recombine with each other.

[0044] The light-emitting element RES has, as its EML43, an island-shaped EML43R (red EML) that emits red light. The light-emitting element GES has, as its EML43, an island-shaped EML43G (green EML) that emits green light. The light-emitting element BES has, as its EML43, an island-shaped EML43B (blue EML) that emits blue light. In this embodiment, when there is no need to particularly distinguish between these EML43R, EML43G, and EML43B, they will be collectively referred to simply as "EML43."

[0045] The blue light is, for example, light having a peak emission wavelength (central emission wavelength) in a wavelength band of 400 nm or more and 500 nm or less. The green light is, for example, light having a peak emission wavelength in a wavelength band of more than 500 nm and less than 600 nm. The red light is, for example, light having a peak emission wavelength in a wavelength band of more than 600 nm and less than 780 nm.

[0046] FIG. 4 is a cross-sectional view showing an enlarged schematic view of a part of the EML 43 of each color in an example of the display device 1 according to the present embodiment.

[0047] The light-emitting element ES according to this embodiment is a quantum dot light-emitting diode (QLED). Therefore, as shown in Fig. 4, the EML 43 is a QD light-emitting layer that contains nano-sized quantum dots (hereinafter, referred to as "QD") 51 corresponding to the emission color as a light-emitting material.

[0048] EML43R is provided with QD51R (red QD) that emits red light as a red light emitting material. EML43G is provided with QD51G (green QD) that emits green light as a green light emitting material. EML43B is provided with QD51B (blue QD) that emits blue light as a blue light emitting material. In this embodiment, when there is no need to particularly distinguish between QD51R, QD51G, and QD51B, they are collectively referred to simply as "QD51".

[0049] The QD51 used in this embodiment is not particularly limited, and various known QDs can be used.

[0050] In this disclosure, QD means a dot with a maximum width of 100 nm or less. QD emits fluorescence, for example, and has a size of nano-order, so it may be called fluorescent nanoparticles or QD phosphor particles. QD is also sometimes called semiconductor nanoparticles because its composition is derived from semiconductor materials. QD is also sometimes called nanocrystals because its structure has a specific crystal structure.

[0051] The shape of QD51 is not particularly limited as long as it satisfies the above-mentioned maximum width, and is not limited to a spherical three-dimensional shape (circular cross-sectional shape). For example, it may be a polygonal cross-sectional shape, a rod-like three-dimensional shape, a branch-like three-dimensional shape, a three-dimensional shape with unevenness on the surface, or a combination thereof.

[0052] QD51 may include a semiconductor material composed of at least one element selected from the group consisting of, for example, Cd (cadmium), S (sulfur), Te (tellurium), Se (selenium), Zn (zinc), In (indium), N (nitrogen), P (phosphorus), As (arsenic), Sb (antimony), Al (aluminum), Ga (gallium), Pb (lead), Si (silicon), Ge (germanium), and Mg (magnesium).

[0053] Also, as an example, QD51 may have a core-shell structure including a core and a shell, and may be a core-shell type or a core-multishell type. When QD51 includes a shell, the shell may be provided on the surface of the core. It is preferable that the shell covers the entire core, but it is not necessary that the shell completely covers the core. Also, QD51 may be a two-component core type, a three-component core type, or a four-component core type. The emission wavelength of QD51 can be changed in various ways depending on the particle size, composition, etc. of the particle.

[0054] As shown in Fig. 4, a large number of ligands are coordinated to the surface of QD51. For convenience of illustration, the numbers of QD51 and ligands are omitted in Fig. 4.

[0055] By coordinating the ligand to the surface of QD51, aggregation of QD51 can be suppressed, and the desired optical properties can be easily expressed. The term "ligand" refers to a compound having a coordinating function. When both the ligand and QD51 are included, it is considered that at least a part of the ligand is coordinated to QD51. In addition, "coordination" refers to the ligand being adsorbed to the surface of QD51 or being present around QD51 (in other words, the ligand modifies the surface of QD51 (surface modification)). Therefore, as explained above about the ligand, when both the ligand and QD51 are included, it is considered that at least a part of the ligand is coordinated to QD51. In addition, "adsorption" refers to the concentration of the ligand being increased on the surface of QD51 compared to the surroundings. The above adsorption may be chemical adsorption in which there is a chemical bond between QD51 and the ligand, or physical adsorption or electrostatic adsorption. The ligand may be bonded by a coordinate bond, a common bond, an ionic bond, a hydrogen bond, or the like, or may not necessarily be bonded, so long as it has a chemical effect on the surface of QD51 by adsorption. As described above, in this embodiment, the term "ligand" refers not only to molecules or ions coordinated to the surface of QD51, but also to molecules or ions that can coordinate but are not coordinated.

[0056] In this way, ligands are provided on the surface of each QD 51. Therefore, each EML 43 contains a ligand. Each EML 43 contains an organic ligand 52 and an inorganic ligand 53 as ligands.

[0057] 2 and 4, the EML 43R according to this embodiment includes a first region 431R and a second region 432R, which differ in the number of inorganic ligands 53R contained per unit volume. Similarly, the EML 43G according to this embodiment includes a first region 431G and a second region 432G, which differ in the number of inorganic ligands 53G contained per unit volume. The EML 43B according to this embodiment includes a first region 431B and a second region 432B, which differ in the number of inorganic ligands 53B contained per unit volume.

[0058] The first region 431R includes QD51R and at least the inorganic ligand 53R among the organic ligand 52R and the inorganic ligand 53R, and is a region in which the number of the inorganic ligands 53R included per unit volume is greater than the number of the inorganic ligands 53R included per unit volume of the second region 432R. The second region 432R includes QD51R and at least the organic ligand 52R among the organic ligand 52R and the inorganic ligand 53R, and is a region in which the number of the inorganic ligands 53R included per unit volume is less than the number of the inorganic ligands 53R included per unit volume of the first region 431R.

[0059] The first region 431G includes QD51G and at least the inorganic ligand 53G among the organic ligand 52G and the inorganic ligand 53G, and is a region in which the number of the inorganic ligands 53G included per unit volume is greater than the number of the inorganic ligands 53G included per unit volume of the second region 432G. The second region 432G includes QD51G and at least the organic ligand 52G among the organic ligand 52G and the inorganic ligand 53G, and is a region in which the number of the inorganic ligands 53G included per unit volume is less than the number of the inorganic ligands 53G included per unit volume of the first region 431G.

[0060] The first region 431B includes QD51B and at least inorganic ligand 53B among organic ligand 52B and inorganic ligand 53B, and is a region in which the number of inorganic ligands 53B included per unit volume is greater than the number of inorganic ligands 53B included per unit volume of the second region 432B. The second region 432B includes QD51B and at least organic ligand 52B among organic ligand 52B and inorganic ligand 53B, and is a region in which the number of inorganic ligands 53B included per unit volume is less than the number of inorganic ligands 53B included per unit volume of the first region 431B.

[0061] 4 illustrates an example in which none of the second region 432R, the second region 432G, and the second region 432B contains an inorganic ligand. Thus, the number of inorganic ligands 53R contained per unit volume of the second region 432R includes a case in which the number of inorganic ligands 53R contained per unit volume of the second region 432R is zero. Similarly, the number of inorganic ligands 53G contained per unit volume of the second region 432G includes a case in which the number of inorganic ligands 53G contained per unit volume of the second region 432G is zero. Moreover, the number of inorganic ligands 53B contained per unit volume of the second region 432B includes a case in which the number of inorganic ligands 53B contained per unit volume of the second region 432B is zero.

[0062] 4 illustrates an example in which the first region 431R, the first region 431G, and the first region 431B all contain the organic ligand 52 and the inorganic ligand 53 as ligands. In the following, an example in which the first region 431R, the first region 431G, and the first region 431B all contain both the organic ligand 52 and the inorganic ligand 53 as ligands will be described. However, the present embodiment is not limited to this, and as described above, the first region 431R, the first region 431G, and the first region 431B only need to contain QD51 and at least the inorganic ligand 53 among the organic ligand 52 and the inorganic ligand 53.

[0063] In this embodiment, when there is no need to particularly distinguish between first region 431R, first region 431G, and first region 431B, they are collectively referred to simply as "first region 431." Similarly, in this embodiment, when there is no need to particularly distinguish between second region 432R, second region 432G, and second region 432B, they are collectively referred to simply as "second region 432."

[0064] In addition, in this embodiment, when there is no need to particularly distinguish between the organic ligand 52R, the organic ligand 52G, and the organic ligand 52B, they are collectively referred to simply as "organic ligand 52" as described above. Similarly, in this embodiment, when there is no need to particularly distinguish between the inorganic ligand 53R, the inorganic ligand 53G, and the inorganic ligand 53B, they are collectively referred to simply as "inorganic ligand 53" as described above. The organic ligand 52R, the organic ligand 52G, and the organic ligand 52B may be the same ligand as each other, or may be different ligands. In addition, the inorganic ligand 53R, the inorganic ligand 53G, and the inorganic ligand 53B may be the same ligand as each other, or may be different ligands.

[0065] The organic ligand 52 may have at least one coordinating functional group capable of coordinating with the QD 51, and various known organic ligands can be used.

[0066] Representative examples of the coordinating functional group include at least one functional group selected from the group consisting of a thiol group, an amino group, a carboxyl group, a phosphonic group, and a phosphine group.

[0067] The organic ligand 52 is not particularly limited, but representative examples include amine-based, fatty acid-based, thiol-based, phosphine-based, phosphine oxide-based, alcohol-based, etc. Examples of such organic ligands include, but are not particularly limited to, oleylamine, oleic acid, dodecanethiol, trioctylphosphine, trioctylphosphine oxide, tributylphosphine oxide, oleyl alcohol, etc.

[0068] QDs are commercially available, and are generally provided in the form of a QD dispersion containing an organic ligand. QDs can be synthesized by any method. For example, a wet method is used for synthesizing QDs, and the particle size of QDs is controlled by coordinating an organic ligand to the surface of the QDs. The organic ligand is used as a dispersant to improve the dispersibility of QDs in the QD dispersion, and is also used to improve the surface stability and storage stability of QDs.

[0069] Therefore, the organic ligand 52 may be an organic ligand coordinated to a QD synthesized or commercially obtained as QD51, or may be a desired organic ligand exchanged by ligand exchange or the like.

[0070] On the other hand, inorganic ligands are more stable than organic ligands and can stably protect the surface of QDs. In addition, inorganic ligands have better current injection into QDs than organic ligands with long hydrocarbon chains, and facilitate carrier transport between individual QDs.

[0071] The inorganic ligand 53 used in this embodiment is not particularly limited, and various known inorganic ligands can be used. - , Cl - , Br - , I - , S 2- , Se 2- , Te 2- , H.S. - , SnS4 4- , Sn2S6 4- These inorganic anions are negatively charged and are therefore attracted to the positively charged surface of QD51 as ligands.

[0072] Among the above inorganic anions, F - , Cl - , Br - , I - , S 2- , Se 2- , Te 2-Anions consisting of inorganic monoatomic ions such as fluorine, fluorine, fluorine-1, fluorine-2, fluorine-3, fluorine-4, fluorine-5, fluorine-6, fluorine-7, fluorine-8, fluorine-9, fluorine-10, fluorine-11, fluorine-12, fluorine-13, fluorine-14, fluorine-15, fluorine-16, fluorine-17, fluorine-18, fluorine-19, fluorine-20, fluorine-21, fluorine-22, fluorine-23, fluorine-24, fluorine-25 ...6, fluorine-27, fluorine-28, fluorine-29, fluorine-30, fluorine-31, fluorine-32 - , Cl - , Br - , I - Ions of halogen atoms, called halogen ligands, such as F, are more preferred because of their high stability and current injection properties. - Particularly preferred is a fluoride ion (an ion of a fluorine atom) represented by the following formula: F (fluorine) has a particularly large electronegativity and is difficult to be eliminated from QD51, so that QD51 can be strongly protected.

[0073] 2, each EML 43 according to the present embodiment is composed of a first region 431 and a second region 432. In each subpixel SP, the region other than the second region 432 in the EML 43 is the first region 431.

[0074] In this embodiment, the second region 432 surrounds the first region 431 in a frame shape. Therefore, the first region 431 of each EML 43 in each subpixel SP includes a central portion of the EML 43 in each subpixel SP. Note that in this embodiment, "the central portion of each EML 43 in each subpixel SP" refers to the center point of each EML 43 in each subpixel SP.

[0075] Furthermore, the second region 432 of each EML 43 in each subpixel SP includes all end portions of the EML 43 that are adjacent to other subpixels SP. Therefore, in this embodiment, the second region 432 of each EML 43 in each subpixel SP includes end portions of the EML 43 that are adjacent to subpixels SP having the same emission color as the subpixel SP in which the EML is provided, and end portions that are adjacent to subpixels SP having a different emission color from the subpixel SP in which the EML is provided.

[0076] The first region 431 is set so that, when the shortest distance from the end of another subpixel SP adjacent to the second region 432 in the EML43 of each subpixel SP to the end of the first region 431 in the EML43 is Δa as shown in FIG. 3, the Δa is within the range of 2.0 μm or more and 8.5 μm or less.

[0077] In other words, if the subpixel SP adjacent to the subpixel SP to be emitted that is originally desired to emit light is defined as the own subpixel SP, if the first region 431 and the second region 432 are not provided in the own subpixel SP, there is a possibility that the own subpixel SP will unintentionally emit light within a distance range of Δa from the end of the adjacent subpixel SP due to leakage current from the subpixel SP to be emitted that is adjacent to the own subpixel SP.

[0078] Therefore, in this embodiment, the position Δa from the end of adjacent subpixels SP in the subpixel SP is set as the boundary position between the first region 431 and the second region 432 of the subpixel SP, and the region inside the boundary line connecting these boundary positions in the subpixel SP is set as the first region 431 of the subpixel SP. The region outside the boundary line is set as the second region 432 of the subpixel SP. The region inside the boundary line refers to the region sandwiched between the two boundary positions in the subpixel SP, including the center of the subpixel SP.

[0079] Thus, in this embodiment, the region in which the QD51 does not emit light due to leakage current from the adjacent subpixel SP even if it contains the inorganic ligand 53 is defined as the first region 431. As described above, in the first region 431, even if the inorganic ligand 53 is contained, the QD51 does not emit light due to leakage current from the adjacent subpixel SP, so by increasing the amount of inorganic ligand 53 per unit volume, it is possible to stably protect the QD51 by the inorganic ligand 53 and improve current injection properties.

[0080] On the other hand, in the second region 432 outside the first region 431, including the end adjacent to another subpixel SP, the amount of inorganic ligand 53 per unit volume is reduced compared to the first region 431, thereby suppressing the emission of QD51 due to leakage current from the adjacent subpixel SP.

[0081] This improves the luminous efficiency of the inorganic ligand 53, while suppressing luminescence due to leakage current from adjacent sub-pixels SP, and suppresses the occurrence of optical crosstalk, such as color mixing and the formation of unclear images. This reduces the luminescence of the sub-pixels SP due to leakage current, and enables the display of high-definition images.

[0082] This will be described in more detail below. Fig. 5 is a cross-sectional view illustrating a leakage current between the first sub-pixel SP1 and the second sub-pixel SP2 of a comparative display device in which the first region 431 and the second region 432 are not provided in the EML 43 of the display device 1 shown in Figs. 2 and 3.

[0083] 5 shows a simplified schematic cross-sectional configuration of a comparative display device in which the first region 431 and the second region 432 are not provided in the EML 43 shown in FIG. 3. The cross section shown in FIG. 5 corresponds to the A-A' cross section shown in FIG. 2. FIG. 6 is a circuit diagram for explaining a leakage current between the first sub-pixel SP1 and the second sub-pixel SP2 of the comparative display device shown in FIG. 5. As shown in FIGS. 5 and 6, a light-emitting element ES1 is provided in the first sub-pixel SP1, and a light-emitting element ES2 is provided in the second sub-pixel SP2.

[0084] In the following, a leakage current flowing from the first sub-pixel SP1 to the second sub-pixel SP2 in the case where the first region 431 and the second region 432 are not provided in the EML 43 as shown in FIGS. 5 and 6 will be discussed.

[0085] In the following, the subpixel width of each subpixel SP is a and the depth of each subpixel SP is b, where a indicates the width of the subpixel SP in the X-axis direction (row direction), which is one of the horizontal axes in Fig. 5, and b indicates the width of the subpixel SP in the Y-axis direction (column direction) perpendicular to the X-axis direction in the horizontal plane.

[0086] 5, the width in the X-axis direction from an end of the first subpixel SP1 to a position where the second subpixel SP2 emits light due to a leakage current from the first subpixel SP1 is defined as Δa. In other words, the distance Δa from the end of the first subpixel SP1 is the aforementioned Δa.

[0087] 6, the maximum drive voltage of the first subpixel SP1 is Vd. The emission threshold voltage of the second subpixel SP2 is Vth, and the current density of the leakage current is j. If the conductivity of the HIL41 is σ, the film thickness of the HIL41 is t, and the resistance due to the HIL41 is R, then R=Δa / (σ×b×t). If the voltage applied to the second subpixel SP2 is equal to the emission threshold voltage Vth, then Vd-RjbΔa=Vth, which can be rearranged to obtain the following equation (1).

[0088] Δa=√((Vd-Vth)×σ×t / j)‥(1) where σ=10 -6 ~10 -5 S / cm, t=40 nm. The first subpixel SP1 and the second subpixel SP2 are subpixels SP of the same color, and Vd-Vth=1 V, j=0.1 mA / cm between the subpixels SP of the same color. 2 Then, between the subpixels SP of the same color, Δa=2.0 to 6.3 μm. Furthermore, one of the first subpixel SP1 and the second subpixel SP2 is the subpixel RSP, and the other is the subpixel BSP. Between the subpixel RSP and the subpixel BSP, Vd-Vth=1.8 V, j=0.1 mA / cm 2 Then, between the subpixel RSP and the subpixel BSP, Δa=2.7 to 8.5 μm.

[0089] Furthermore, one of the first subpixel SP1 and the second subpixel SP2 is the subpixel GSP, and the other is the subpixel BSP. Between the subpixel GSP and the subpixel BSP, Vd-Vth=1.5 V, j=0.1 mA / cm 2 Then, between the subpixel GSP and the subpixel BSP, Δa=2.4 to 7.7 μm. In addition, one of the first subpixel SP1 and the second subpixel SP2 is the subpixel RSP, and the other is the subpixel GSP. Between the subpixel RSP and the subpixel GSP, Vd-Vth=1.3 V, j=0.1 mA / cm 2 Then, between the subpixel RSP and the subpixel GSP, Δa=2.3 to 7.2 μm.

[0090] For this reason, it is desirable to set the shortest distance from an end of another subpixel SP adjacent to the second region 432 to an end of the first region 431 of the subpixel SP in the EML 43 of the subpixel SP so that the range of Δa is within the range of Δa according to the emission color of the subpixel SP and the emission color of the subpixel SP adjacent to the subpixel SP. This not only reduces the leakage current, but also makes it possible to minimize the amount of inorganic ligand 53 used, thereby reducing material costs. However, making the Δa the same regardless of the emission color of the subpixel SP and the emission color of the subpixel SP adjacent to the subpixel SP facilitates design and manufacturing.

[0091] Next, a preferred ratio of the inorganic ligands 53 to the total number of the organic ligands 52 and the inorganic ligands 53 in the first region 431 will be described.

[0092] The inorganic ligand 53 is more stable than the organic ligand 52 and has excellent current injection properties. Therefore, as described above, the first region 431 may contain at least the inorganic ligand 53 among the organic ligand 52 and the inorganic ligand 53 as a ligand. Therefore, the ratio of the inorganic ligand 53 to the total number of the organic ligands 52 and the inorganic ligands 53 in the first region 431 may be 100%. In other words, the first region 431 may contain only the inorganic ligand 53 among the organic ligand 52 and the inorganic ligand 53. Note that the case where the first region 431 contains only the inorganic ligand 53 as a ligand will be described in the embodiment described later. However, in order to prevent aggregation between the QD51, it is desirable that the first region 431 contains the organic ligand 52.

[0093] Therefore, the maximum ratio of inorganic ligands 53 that is preferable for preventing aggregation of QD51 is calculated.

[0094] For example, if the particle size of QD51 is 3 nm, the surface area of ​​QD51 calculated from the particle size of QD51 is 28 nm if the QD is assumed to be a sphere. 2 If the inorganic ligand 53 is, for example, F - In this case, the ligand diameter of the inorganic ligand 53 is F - The area occupied by one inorganic ligand 53 is calculated from the ligand diameter of the inorganic ligand 53, and is thus 0.26 nm. - If it is, 0.05 nm 2 It becomes.

[0095] The number of inorganic ligands 53 per QD51 can be calculated by dividing the surface area of ​​QD51 by the area occupied by one inorganic ligand 53. Therefore, in this example, the number of inorganic ligands 53 per QD51 is 533.

[0096] Also, consider the number of organic ligands 52 per QD51. When QD51 are closely packed in EML43, 12 QD51 are adjacent to each QD51. In general, organic ligands are easily dislodged due to environmental factors such as heat and the coating process. For this reason, in order to prevent QD51 from agglomerating, it is desirable to have about 10 organic ligands 52 per adjacent QD51. In this case, the number of organic ligands 52 per QD51 is 120.

[0097] Therefore, the maximum proportion of inorganic ligands 53 in the total number of organic ligands 52 and inorganic ligands 53 (i.e., the number of inorganic ligands 53 / (the number of inorganic ligands 53+the number of organic ligands 52)) that is preferable for preventing aggregation of QDs 51 is 82%.

[0098] In the first region 431, the amount of inorganic ligands 53 increases, and the amount of organic ligands 52 coordinated to QD51 decreases, making it easier to inject current. On the other hand, in the second region 432 located in the subpixel periphery, if the ratio of inorganic ligands 53 to the total number of organic ligands 52 and inorganic ligands 53 is reduced (in other words, the ratio of organic ligands 52 is increased), it becomes difficult to inject carriers into QD51 in the subpixel periphery. For this reason, if the emission threshold voltage of the subpixel central portion, which is the first region 431, is Vth1 and the emission threshold voltage of the subpixel peripheral portion, which is the second region 432, is Vth2, Vth2 increases compared to Vth1.

[0099] According to the experimental results, when inorganic ligand 53 is not added (i.e., when the proportion of inorganic ligand 53 is 0%), the light emission threshold voltage Vth2 increases by about 2 V compared to the light emission threshold voltage Vth1 when inorganic ligand 53 is added up to the above-mentioned proportion of inorganic ligand 53 (82%).

[0100] The increase V(r) of the emission threshold voltage Vth2 (emission threshold voltage increase) when the ratio of inorganic ligands 53 to the total number of organic ligands 52 and inorganic ligands 53 is r is determined by the difficulty of injecting current into QD51 (the ratio of organic ligands 52 to the surface area of ​​QD51). Here, V(r)=Vth2-Vth1, and the V(r) is linear with respect to the ratio of organic ligands 52. Therefore, the V(r) is linear with respect to r. Therefore, V(r) [unit: V] is given by the following formula (2).

[0101] V(r) = 2.44 × (0.82 - r) (2) In order to prevent the peripheral portion of the subpixel in the subpixel SP from emitting light due to driving of the subpixel SP adjacent to the subpixel SP, it is desirable for V(r) to be equal to or greater than 1 V. Here, 1 V refers to the difference between Vdm and Vth when the maximum drive voltage of each subpixel SP is Vdm and the emission threshold voltage of each subpixel SP is Vth, and specifically refers to the difference (Vdm-Vth) between the maximum drive voltage (Vdm) of the subpixel SP adjacent to the subpixel SP to be emitted and the emission threshold voltage (Vth) of the subpixel SP.

[0102] In this embodiment, the light emission threshold voltage is a voltage at which the light emitting element ES starts to emit light when the voltage applied to the light emitting element ES is increased (for example, when the light emitting element has a luminance of 1 cd / m 2 The device structures of HTL42, ETL44, etc. have been optimized, and in the ideal case, the light emission threshold voltage is the voltage converted from the band gap (Eg) of QD51.

[0103] For example, if the emission peak wavelength (λ) of the subpixel RSP is 620 nm and Eg=2.0 eV, then ideally the emission threshold voltage of the subpixel RSP is 2.0 V. If the emission peak wavelength (λ) of the subpixel GSP is 530 nm and Eg=2.3 eV, then ideally the emission threshold voltage of the subpixel GSP is 2.3 V. If the emission peak wavelength (λ) of the subpixel BSP is 450 nm and Eg=2.8 eV, then ideally the emission threshold voltage of the subpixel BSP is 2.8 V.

[0104] When the amount of organic ligand 52 is large or the like, and current injection is hindered, the light emission threshold voltage becomes high, and unless a high voltage is applied, current cannot be injected into QD 51, and light does not come out.

[0105] The maximum driving voltage is the voltage required to drive the light-emitting element ES at the maximum luminance (e.g., 100 cd / m 2 ), which is roughly the light emission threshold voltage +1 V. Therefore, Vdm-Vth=1 V. Each light-emitting element ES in the display device 1 is driven at a voltage equal to or higher than the light emission threshold voltage (Vth) and equal to or lower than the maximum driving voltage (Vdm).

[0106] Light emission due to leakage current occurs when the maximum driving voltage (Vd) leaking from a subpixel SP to be lit that is adjacent to the subpixel SP itself exceeds the light emission threshold voltage (Vth) of the subpixel SP itself, and is caused by a current corresponding to the difference in voltage that is exceeded.

[0107] Therefore, the potential difference between the subpixel SP adjacent to the subpixel SP to be emitted and the subpixel itself is calculated from the difference (Vdm-Vth) between the maximum drive voltage (Vdm) of the subpixel SP to be emitted adjacent to the subpixel SP and the emission threshold voltage (Vth) of the subpixel SP, and the leakage current is estimated from the potential difference and the conductivity of the HIL 41. The amount (proportion) of inorganic ligand 53 in the region where the potential difference exceeds the emission threshold voltage (Vth) of the subpixel SP is reduced, thereby increasing the emission threshold voltage (Vth) of the subpixel SP. Note that the region where the potential difference exceeds the emission threshold voltage (Vth) of the subpixel SP is defined as a region where the current density value of the leakage current is 0.1 mA / cm. 2 and indicates a region having a width of Δa with an end of the sub-pixel SP adjacent to the sub-pixel SP as a base point.

[0108] Note that the emission threshold voltage (Vth) in this case is the value when the present disclosure is not applied (i.e., the value when the inorganic ligand 53 is evenly contained in the subpixel SP). For this reason, the above-mentioned formula (2) is used to determine how much the emission threshold voltage (Vth) when the present disclosure is used increases from the emission threshold voltage (Vth) when the present disclosure is not applied due to changes in the amount of inorganic ligand 53. As described above, this emission threshold increase amount (V(r)) needs to be at least 1 V or more (i.e., V(r)≧1).

[0109] To achieve this, it is desirable that r≦0.41, and it is desirable that in the second region 432 of the EML 43 in the subpixel periphery, the proportion (r) of inorganic ligands 53 in the total number of organic ligands 52 and inorganic ligands 53 is 0% or more and 41% or less.

[0110] In addition, since the maximum driving voltage (Vdm) differs depending on the subpixel SP of each color, it is preferable to define the emission threshold rise amount (V(r)) taking into consideration the difference in the maximum driving voltage (Vd). As described above, the difference in the band gap (Eg) of QD51 between adjacent subpixels SP and the difference in the emission threshold voltage obtained by converting these band gaps (Eg) into voltage are the largest between the subpixels RSP and BSP. Therefore, it is more preferable that the emission threshold rise amount (V(r)) is 1.8V (i.e., 1+0.8V) or more (V(r)≧1.8) taking into consideration the maximum driving voltage difference of 0.8V due to the emission threshold voltage difference (0.8V) between the subpixels RSP and BSP in addition to the 1V. Therefore, when the ratio (r) of the inorganic ligands 53 to the total number of the organic ligands 52 and the inorganic ligands 53 is defined using these conditions, it is preferable that r≦0.082. Therefore, in this case, the ratio (r) of the inorganic ligands 53 to the total number of the organic ligands 52 and the inorganic ligands 53 in the second region 432 of the EML 43 in the subpixel periphery is preferably 0% or more and 8.2% or less.

[0111] Therefore, in the first region 431 of the EML 43 at the center of the subpixel, the ratio (r) of the inorganic ligands 53 to the total number of the organic ligands 52 and the inorganic ligands 53 is preferably 8.2% or more and 100% or less, and more preferably 8.2% or more and 82% or less. Moreover, in the first region 431, the ratio (r) of the inorganic ligands 53 to the total number of the organic ligands 52 and the inorganic ligands 53 is further preferably 41% or more and 82% or less.

[0112] The ratio (r) of the inorganic ligand 53 in the first region 431 and the ratio (r) of the inorganic ligand 53 in the second region 432 can be appropriately set (selected) within the above-mentioned range. However, a combination in which the ratio (r) of the inorganic ligand 53 is equal between the first region 431 and the second region 432, or the ratio (r) of the inorganic ligand 53 in the second region 432 is greater than that in the first region 431, is excluded.

[0113] The formation of the first region 431 and the second region 432 in the EML 43 can be confirmed by examining the distribution of the inorganic ligands 53 in the EML 43 using cross-sectional SEM-EDX (scanning electron microscope-energy dispersive X-ray spectroscopy). The number of the inorganic ligands 53 per unit volume in the first region 431 and the second region 432 can be determined using the cross-sectional SEM-EDX. Since inorganic ligands 53 such as halogens have strong coordinating power, if these inorganic ligands 53 are present in the EML 43, it can be considered that the inorganic ligands 53 are coordinated to the QDs 51.

[0114] According to this embodiment, by providing the first region 431 and the second region 432 in the EML 43 as described above, it is possible to achieve both improvement in the luminous efficiency by the inorganic ligand 53 and suppression of luminescence due to leakage current from adjacent sub-pixels SP, and also to narrow the spacing between the sub-pixels SP.

[0115] When the light-emitting element ES, which is a QLED (nano LED), is used in the display device 1, narrowing the interval between the subpixels SP is of great significance. For example, by narrowing the interval between the subpixels SP, the area of ​​the subpixels SP can be increased within the pixel P of the same area. This increases the luminance of the subpixels SP and the pixel P, and a brighter display device 1 can be realized. In addition, if the area of ​​the subpixels SP is constant and the number of pixels of the display device 1 is constant, the area of ​​the display device 1 can be reduced by narrowing the interval between the subpixels SP, which can reduce the manufacturing cost and the weight of the display device 1. In addition, if the area of ​​the subpixels SP is constant and the area of ​​the display device 1 is constant, the number of pixels of the display device 1 can be increased by narrowing the interval between the subpixels SP, which can be expected to improve the resolution of the image.

[0116] However, while narrowing the spacing between the subpixels SP has the above-mentioned advantages, it also poses the problem of light emission due to leakage current from adjacent subpixels SP. When unintended light emission occurs in the subpixels SP, optical crosstalk occurs, which can cause color mixing or the formation of unclear images. Such crosstalk can cause a decrease in the display quality of the display device.

[0117] According to this embodiment, as described above, by providing the above-mentioned first region 431 and second region 432 in the EML 43, it is possible to suppress the above-mentioned optical crosstalk from occurring even if the interval between the subpixels SP is narrowed. Therefore, according to this embodiment, it is possible to achieve both improvement in luminous efficiency by the inorganic ligand 53 and suppression of luminescence due to leakage current from adjacent subpixels SP, and it is possible to further narrow the interval between the subpixels SP and provide a display device 1 with excellent display quality.

[0118] The display device 1 may include, for example, a first subpixel (e.g., subpixel RSP) and a second subpixel (e.g., subpixel GSP) adjacent to the first subpixel in a first direction (e.g., horizontal direction, row direction), and the first subpixel includes an anode (positive electrode 31) and a cathode (negative electrode 34), and a first light-emitting layer (e.g., EML43R) located between them and containing QD51 and an inorganic ligand 53 (e.g., a halogen ligand), and the first light-emitting layer may include a first end (e.g., a right side portion of the second region 432R extending in the vertical direction (column direction)), a central portion (e.g., at least a part of the first region 431R), and a second end (e.g., a left side portion of the second region 432R extending in the vertical direction), which are aligned in the first direction, and the number of inorganic ligands 53 per unit volume of the first end may be smaller than the number of inorganic ligands 53 per unit volume of the central portion. In addition, the second sub-pixel (e.g., sub-pixel GSP) may be adjacent to the first end portion and may be configured to emit light of a color different from that of the first sub-pixel (e.g., sub-pixel RSP) (e.g., a green wavelength range that is a shorter wavelength range than the red-emitting first sub-pixel).

[0119] (Manufacturing method of display device 1) Next, a method for manufacturing the display device 1 according to this embodiment will be described below by taking the method for manufacturing the display device 1 shown in FIG. 3 as an example.

[0120] FIG. 7 is a flowchart showing an example of a method for manufacturing the display device 1 according to this embodiment.

[0121] As shown in FIG. 7, in this embodiment, first, a substrate 2 is formed (step S1, substrate formation step). Next, as a first electrode, for example, an anode 31 is formed as shown in FIG. 3 (step S2, first electrode formation step). Next, a bank 32 is formed (step S3, bank formation step). Next, a functional layer 33 is formed (step S4, functional layer formation step). Next, as a second electrode, for example, a cathode 34 is formed as shown in FIG. 3 (step S5, second electrode formation step).

[0122] In step S1, the substrate 2 may be formed by forming TFTs on a supporting substrate in accordance with the positions where the sub-pixels SP of the display device 1 are to be formed.

[0123] The first electrode is formed in an island shape for each subpixel SP. For this reason, in step S2, the first electrode is formed in an island shape to match the position where each subpixel SP of the display device 1 is to be formed. The first electrode may be formed by depositing the conductive material in a solid shape on all the subpixels SP, and then patterning the film made of the conductive material into an island shape for each subpixel SP by photolithography. Alternatively, the first electrode may be formed by patterning the film made of the conductive material into an island shape for each subpixel SP.

[0124] On the other hand, the second electrode is a common electrode, and is formed in step S5 by depositing the conductive material in a solid manner common to all the sub-pixels SP.

[0125] In steps S2 and S5, the conductive material can be deposited by physical vapor deposition (PVD) such as sputtering or vacuum deposition, spin coating, or ink-jet printing.

[0126] In step S3, the bank 32 can be formed into a desired shape, for example, by applying the photosensitive resin with a light absorbing agent added thereto onto the substrate 2 and the first electrode, and then patterning the resin by photolithography.

[0127] FIG. 8 is a flow chart showing an example of the functional layer forming step (step S4).

[0128] When the first electrode is, for example, an anode 31 as described above, in the functional layer formation step (step S4), as shown in FIG. 8, first, an HIL 41 is formed as a first current injection layer (step S11, hole injection layer formation step). Next, an HTL 42 is formed as a first carrier transport layer (step S12, hole transport layer formation step). Next, an EML 43 of each color is formed (step S13, light-emitting layer formation step). Next, an ETL 44 is formed as a second carrier transport layer (step S14, electron transport layer formation step).

[0129] In step S11, when the HIL 41 is made of an organic material, for example, a vacuum deposition method, a spin coating method, an inkjet method, or the like is preferably used for forming the HIL 41. On the other hand, when the HIL 41 is made of an inorganic material, for example, a PVD method such as a sputtering method or a vacuum deposition method, a spin coating method, or an inkjet method is preferably used for forming the HIL 41.

[0130] The deposition of the HTL 42 in step S12 and the deposition of the ETL 44 in step S14 are performed using the same method as the method exemplified in step S11. That is, when the deposition material used to deposit the HTL 42 or the ETL 44 is an organic material, the deposition of the organic material is preferably performed using, for example, PVD such as sputtering or vacuum deposition, spin coating, or inkjet printing. When the ETL 44 is made of an organic material, the deposition of the ETL 44 is preferably performed using, for example, vacuum deposition, spin coating, or inkjet printing.

[0131] The above-mentioned process order is for the case where the first electrode is, for example, the anode 31 as described above, and when the first electrode is the cathode 34 as described above, the process order is reversed from that shown in Fig. 8. In addition, a process of forming an electron injection layer (EIL) may be included between the process of forming the ETL 44 and the process of forming the cathode 34.

[0132] FIG. 9 is a flow chart showing an example of the light emitting layer forming step (step S13).

[0133] 9, in the light-emitting layer forming step (step S13), first, an EML 43 is formed as a first light-emitting layer in the subpixel SP as the first subpixel (step S21, first light-emitting layer forming step). Next, an EML 43 is formed as a second light-emitting layer in the subpixel SP as the second subpixel (step S22, second light-emitting layer forming step). Next, an EML 43 is formed as a third light-emitting layer in the subpixel SP as the third subpixel (step S23, third light-emitting layer forming step).

[0134] The first emitting layer contains a first QD as QD51, a first organic ligand as organic ligand 52, and a first inorganic ligand as inorganic ligand 53. The second emitting layer contains a second QD as QD51, a second organic ligand as organic ligand 52, and a second inorganic ligand as inorganic ligand 53. The third emitting layer contains a third QD as QD51, a third organic ligand as organic ligand 52, and a third inorganic ligand as inorganic ligand 53.

[0135] Hereinafter, the light-emitting layer formation process in step S13 will be described in more detail with reference to FIGS. 10 to 15, taking as an example a case where the first light-emitting layer is EML43R, the second light-emitting layer is EML43G, and the third light-emitting layer is EML43B.

[0136] However, this embodiment is not limited to only the following examples. The order of formation of EML43R, EML43G, and EML43B is not particularly limited, and the order of formation of these EML43R, EML43G, and EML43B can be interchanged. Therefore, the first light-emitting layer may be EML43G or EML43B. Similarly, the second light-emitting layer may be EML43R or EML43B. Moreover, the third light-emitting layer may be EML43R or EML43G.

[0137] FIG. 10 is a cross-sectional view showing an example of a part of the first light-emitting layer forming step (Step S21).

[0138] In the first light-emitting layer forming step, first, a first resist that covers the entirety of the sub-pixels SP (i.e., the entirety of the pixel region DA) is applied onto, for example, the HTL 42 that serves as a base layer supporting the EML 43 of each color. This forms a solid first resist layer RL1 on the HTL 42 (step S31, first resist layer forming step).

[0139] The thickness of the first resist layer RL1 is not particularly limited, but may be, for example, 1 μm to 2 μm.

[0140] Next, the portion of the first resist layer RL1 corresponding to the region 43PR where the red EML is to be formed is exposed and developed, thereby removing the first resist layer RL1 from the portion corresponding to the region where the EML 43R as the first light-emitting layer is to be formed, and patterning the first resist layer RL1 (step S32, first resist layer patterning step).

[0141] Here, the red EML formation region 43PR refers to a region on the HTL 42 that is the base layer where the EML 43R is to be formed (region where the first light-emitting layer is to be formed).

[0142] As described above, the first resist layer patterning process (step S32) includes a first resist layer exposure process (step S41) for exposing a portion of the first resist layer RL1 corresponding to the region 43PR where the red EML is to be formed, and a first resist layer developing process (step S42) for developing the first resist layer RL1 with a developer.

[0143] In the first resist layer patterning step, first, a portion of the first resist layer RL1 corresponding to the region 43PR in which the red EML is to be formed is exposed using a mask M1 (step S41, first resist layer exposure step).

[0144] 10 illustrates an example in which a positive photoresist is used as the first resist. The solubility of the positive photoresist in a developer increases when exposed to ultraviolet (UV) light or the like. Therefore, a mask that exposes a portion of the first resist layer RL1 corresponding to the region 43PR in which the red EML is to be formed is used as the mask M1. In other words, a mask having an opening (optical opening) is used so that the portion of the mask M1 corresponding to the region 43PR in which the red EML is to be formed has light-transmitting properties, and the portion other than the portion corresponding to the region 43PR in which the red EML is to be formed has light-shielding properties.

[0145] In addition, the light irradiation intensity, such as UV irradiation intensity, in the above step S41 can be appropriately set according to the layer thickness of the first resist layer RL1, etc., so that the portion of the first resist layer RL1 corresponding to the region 43PR where the red EML is to be formed is removed by development, and is not particularly limited.

[0146] Next, the first resist layer RL1 is developed with a developer (step S42, first resist layer developing step). As a result, the exposed portion of the first resist layer RL1 is removed, and a first resist pattern RP1 made of the first resist layer RL1 is formed only in the portion of the HTL 42 other than the region 43PR where the red EML is to be formed.

[0147] As the developer, for example, an alkaline water-based developer (alkaline aqueous solution) such as an aqueous solution of tetramethylammonium hydroxide (TMAH) is used.

[0148] The concentration of the developer is not particularly limited and may be appropriately set depending on the thickness of the first resist layer RL1 and the type of developer, etc., so that the portion of the first resist layer RL1 corresponding to the region 43PR where the red EML is to be formed is removed by development.

[0149] 10, as described above, a positive photoresist is used as the first resist layer RL1. However, this embodiment is not limited to this, and a negative photoresist may be used instead of the positive photoresist. The solubility of the negative photoresist in the developer decreases when exposed to light. Therefore, in this case, a mask M1 used for exposing the first resist layer RL1 may be a mask that exposes the portions of the first resist layer RL1 other than the region 43PR where the red EML is to be formed.

[0150] In this manner, by exposing and developing the portion of the first resist layer RL1 corresponding to the region where the first light-emitting layer is intended to be formed, the first resist layer RL1 in the portion corresponding to the region where the first light-emitting layer is intended to be formed can be removed and the first resist layer RL1 can be patterned.

[0151] After the first resist layer patterning step, the red QD-containing layer 143R as the first QD-containing layer is formed in a solid shape covering the entirety of the subpixels SP (i.e., the entirety of the pixel region DA) (step S33, first QD-containing layer formation step). The red QD-containing layer 143R contains QD51R as the first QD, and at least the organic ligand 52R among the organic ligand 52R as the first organic ligand and the inorganic ligand 53R as the first inorganic ligand.

[0152] Next, the first resist pattern RP1 made of the first resist layer RL1 is peeled off with a resist solvent, thereby lifting off the red QD-containing layer 143R on the first resist pattern RP1, and removing the red QD-containing layer 143R other than the red EML formation region 43PR (step S34, first QD-containing layer patterning step).

[0153] By carrying out the above steps S31 to S34, a red QD-containing layer pattern 143PR as a first QD-containing layer pattern made of the red QD-containing layer 143R is formed in the red EML formation region 43PR.

[0154] As the resist solvent, for example, a known resist solvent such as propylene glycol monomethyl ether acetate (PGMEA) can be used.

[0155] Fig. 11 is a partially enlarged cross-sectional view that illustrates the process in the first light-emitting layer formation step (step S21) that follows Fig. 10. For convenience of illustration, the numbers of QD51R and ligands are omitted in Fig. 11.

[0156] After the first QD-containing layer patterning step, in this embodiment, as shown in Fig. 11, a second resist is applied to cover the entirety of the sub-pixels SP (i.e., the entirety of the pixel region DA) on the HTL42 as the underlayer so as to cover the red QD-containing layer pattern 143PR. This forms a solid second resist layer RL2 on the HTL42 on which the red QD-containing layer pattern 143PR is formed (step S35, second resist layer formation step).

[0157] The thickness of the second resist layer RL2 is not particularly limited, but may be, for example, 1 μm to 2 μm, similar to the thickness of the first resist layer RL1.

[0158] Next, the portion of the second resist layer RL2 corresponding to the first region formation planned region 431PR is exposed and developed. As a result, an opening OP2a (first opening) that exposes the first region formation planned region 431PR in the red QD-containing layer pattern 143PR (i.e., the patterned red QD-containing layer 143R) is formed in the second resist layer RL2 (step S36, second resist layer first patterning step). Here, the first region formation planned region 431PR refers to the region where the first region 431R is finally formed in the EML 43R as the first light emitting layer.

[0159] As described above, the second resist layer first patterning process (step S36) includes a second resist layer first exposure process (step S51) for exposing a portion of the second resist layer RL2 corresponding to the planned first region formation region 431PR, and a second resist layer first development process (step S52) for developing the second resist layer RL2 with a developer.

[0160] In the second resist layer first patterning step, first, a portion of the second resist layer RL2 corresponding to the first region formation region 431PR is exposed using a mask M2 (step S51, second resist layer first exposure step).

[0161] 11 shows an example in which a positive photoresist is used for the second resist. Therefore, a mask that exposes a portion of the second resist layer RL2 corresponding to the first region formation planned region 431PR is used for the mask M2. In other words, a mask having an opening (optical opening) is used for the mask M2 so that the portion of the mask M2 corresponding to the first region formation planned region 431PR has light-transmitting properties, and the portion other than the portion corresponding to the first region formation planned region 431PR has light-shielding properties.

[0162] In addition, the light irradiation intensity, such as the UV irradiation intensity, in the above step S51 can be appropriately set according to the layer thickness of the second resist layer RL2, etc., so that the portion of the second resist layer RL2 corresponding to the region 431PR where the first region is to be formed is removed by development, and is not particularly limited.

[0163] Next, the second resist layer RL2 is developed with a developer (step S52, second resist layer first developing step). As a result, the exposed portion of the second resist layer RL2 is removed, and the opening OP2a is formed in the portion of the second resist layer RL2 corresponding to the first region formation planned region 431PR.

[0164] The developer may be, for example, any of the above-mentioned developers. The concentration of the developer may be appropriately set according to the thickness of the resist layer (the second resist layer RL2 in step S52) and the type of developer, and is not particularly limited.

[0165] 11, a positive photoresist is used for the second resist layer RL2, as in the first resist layer RL1. However, the second resist layer RL2 may also use a negative photoresist instead of a positive photoresist. In this case, the mask M2 may be a mask that exposes the portions of the second resist layer RL2 other than the portion corresponding to the first region formation region 431PR.

[0166] In the following steps, a negative photoresist may be used as the resist layer, and the layer thickness, exposure intensity, and developer of these resist layers are the same as those described above, so that the description of these will be omitted below.

[0167] In this way, by exposing and developing the portion of the second resist layer RL2 corresponding to the region 431PR where the first region is to be formed, and patterning the second resist layer RL2, it is possible to expose only the region 431PR where the first region is to be formed in the red QD-containing layer pattern 143PR.

[0168] Therefore, after the second resist layer first patterning step, a first inorganic ligand solution containing an inorganic ligand 53R as a first inorganic ligand is applied to the first region formation planned region 431PR exposed from the opening OP2a in the red QD-containing layer pattern 143PR. This supplies the inorganic ligand 53R to the first region formation planned region 431PR (step S37, first inorganic ligand supply step).

[0169] By supplying the inorganic ligands 53R to the first region formation planned region 431PR in this manner, the number of inorganic ligands 53R contained per unit volume in the first region formation planned region 431PR becomes greater than the number of inorganic ligands 53R contained per unit volume in the region other than the first region formation planned region 431PR. In this embodiment, the region other than the first region formation planned region 431PR in the red QD-containing layer pattern 143PR becomes the second region 432R of the EML 43R.

[0170] At least a part of the inorganic ligand 53R contained in the first inorganic ligand solution supplied to the first region-formation-planned region 431PR is coordinated to the QD51R in the first region-formation-planned region 431PR.

[0171] The first inorganic ligand solution contains the inorganic ligand 53R and a first solvent that dissolves or disperses the inorganic ligand 53R. The EML43R is formed by removing the solvent contained in the first inorganic ligand solution applied to the first region formation planned region 431PR and drying the solution.

[0172] The first solvent is preferably a polar solvent other than water that is liquid at room temperature, such as a non-aqueous polar solvent such as DMSO (dimethyl sulfoxide), or an amphoteric solvent such as methanol or ethanol.

[0173] The concentration of the inorganic ligand 53R in the first inorganic ligand solution and the time taken for supplying the first inorganic ligand solution are not particularly limited, and may be appropriately set so that the proportion of the inorganic ligands 53R in the total number of the organic ligands 52R and the inorganic ligands 53R in the first region 431R becomes the desired proportion described above.

[0174] Furthermore, the temperature at which the first solvent is removed (in other words, the drying temperature) and the drying time are not particularly limited, and may be appropriately set so that the first solvent is removed.

[0175] As a result, an EML 43R having a first region 431R and a second region 432R is formed.

[0176] FIG. 12 is a cross-sectional view showing an example of a part of the second light-emitting layer forming step (Step S22).

[0177] In the second light emitting layer forming step according to this embodiment, the second resist layer RL2 used in forming the first region 431R in the EML 43R is used as is for forming the EML 43G as the second light emitting layer without being removed.

[0178] 12, in the second light-emitting layer forming step, after the first inorganic ligand supplying step (step S37), the second resist is applied again into the opening OP2a to backfill the opening OP2a with the second resist (step S61, second resist reapplication step). As a result, a solid second resist layer RL2 covering the EML43R is formed on the HTL42.

[0179] By filling the opening OP2a with the second resist in this manner, the second resist layer RL2 used in forming the first region 431R in the EML43R can be utilized. Therefore, it is not necessary to peel off the second resist layer RL2 used in forming the first region 431R after forming the first region 431R, or to form a resist layer from scratch in order to form the EML43G after peeling off the second resist layer RL2. Therefore, compared to such a case, it is possible to reduce the number of times the resist is applied and peeled off.

[0180] After the second resist reapplication step (step S61), the portion of the second resist layer RL2 corresponding to the green EML formation region 43PG is exposed and developed, thereby removing the second resist layer RL2 from the portion corresponding to the formation region of the EML 43G as the second light-emitting layer, and patterning the second resist layer RL2 (step S62, second resist layer second patterning step).

[0181] Here, the green EML formation region 43PG refers to a region on the HTL 42 that is the base layer where the EML 43G is to be formed (region where the second light-emitting layer is to be formed).

[0182] As described above, the second resist layer second patterning process (step S62) includes a second resist layer second exposure process (step S71) for exposing a portion of the second resist layer RL2 corresponding to the planned green EML formation region 43PG, and a second resist layer second development process (step S72) for developing the second resist layer RL2 with a developer.

[0183] In the second resist layer second patterning step, the second resist layer RL2 is exposed to light using a mask M3 that exposes a portion of the second resist layer RL2 corresponding to the region 43PG where the green EML is to be formed (step S71, second resist layer second exposure step). The mask M3 has an opening (optical opening) so that the portion of the mask M3 corresponding to the region 43PG where the green EML is to be formed has light-transmitting properties and the other portion of the mask M3 other than the region 43PG where the green EML is to be formed has light-shielding properties.

[0184] Next, the second resist layer RL2 is developed with a developer (step S72, second resist layer second developing step). As a result, the exposed portion of the second resist layer RL2 is removed, and a second resist pattern RP2 made of the second resist layer RL2 is formed only in the portion of the HTL 42 other than the green EML formation region 43PG.

[0185] After the second resist layer second patterning step, the green QD-containing layer 143G as the second QD-containing layer is formed in a solid shape covering the entirety of the subpixels SP (i.e., the entirety of the pixel region DA) (step S63, second QD-containing layer formation step). The green QD-containing layer 143G includes QD51G as the second QD, and at least the organic ligand 52G among the organic ligand 52G as the second organic ligand and the inorganic ligand 53G as the second inorganic ligand.

[0186] Next, the second resist pattern RP2 made of the second resist layer RL2 is peeled off, for example, with the resist solvent described above, thereby lifting off the green QD-containing layer 143G on the second resist pattern RP2, and removing the green QD-containing layer 143G other than the green EML formation region 43PG (step S64, second QD-containing layer patterning step).

[0187] By carrying out the above steps S61 to S64, a green QD-containing layer pattern 143PG as a second QD-containing layer pattern made of the green QD-containing layer 143G is formed in the green EML formation region 43PG.

[0188] Fig. 13 is a partially enlarged cross-sectional view showing a schematic diagram of the process of forming the second light-emitting layer (step S22) subsequent to Fig. 12. For convenience of illustration, the numbers of QD51R, QD51G, and ligands are omitted in Fig. 13.

[0189] After the second QD-containing layer patterning step, in this embodiment, as shown in Fig. 13, a third resist is applied to cover the entirety of the sub-pixels SP (i.e., the entirety of the pixel region DA) on the HTL42 as the underlayer so as to cover the EML43R and the green QD-containing layer pattern 143PG. This forms a solid third resist layer RL3 on the HTL42 on which the EML43R and the green QD-containing layer pattern 143PG are formed (step S65, third resist layer formation step).

[0190] Next, the portion of the third resist layer RL3 corresponding to the first region formation planned region 431PG is exposed and developed. As a result, an opening OP4a (second opening) that exposes the first region formation planned region 431PG in the green QD-containing layer pattern 143PG (i.e., the patterned green QD-containing layer 143G) is formed in the third resist layer RL3 (step S66, third resist layer first patterning step). Here, the first region formation planned region 431PG refers to the region where the first region 431G in the EML 43G as the second light-emitting layer is finally formed.

[0191] As described above, the third resist layer first patterning process (step S66) includes a third resist layer first exposure process (step S81) for exposing a portion of the third resist layer RL3 corresponding to the first region formation planned region 431PG, and a third resist layer first development process (step S82) for developing the third resist layer RL3 with a developer.

[0192] In the third resist layer first patterning step, first, a portion of the third resist layer RL3 corresponding to the first region formation region 431PG is exposed using a mask M4 (step S81, third resist layer first exposure step).

[0193] 13 shows an example in which a positive photoresist is used for the third resist. Therefore, a mask that exposes a portion of the third resist layer RL3 corresponding to the first region formation planned region 431PG is used for the mask M4. In other words, a mask having an opening (optical opening) is used for the mask M4 so that the portion of the mask M4 corresponding to the first region formation planned region 431PG has light-transmitting properties, and the portion other than the portion corresponding to the first region formation planned region 431PG has light-shielding properties.

[0194] Next, the third resist layer RL3 is developed with a developer (step S82, third resist layer first developing step). As a result, the exposed portion of the third resist layer RL3 is removed, and the opening OP4a is formed in the portion of the third resist layer RL3 corresponding to the first region formation planned region 431PG.

[0195] In this way, by exposing and developing the portion of the third resist layer RL3 corresponding to the region 431PG where the first region is to be formed, and patterning the third resist layer RL3, it is possible to expose only the region 431PG where the first region is to be formed in the green QD-containing layer pattern 143PG.

[0196] Therefore, after the third resist layer first patterning step, a second inorganic ligand solution containing an inorganic ligand 53G as a second inorganic ligand is applied to the first region formation planned region 431PG exposed from the opening OP4a in the green QD-containing layer pattern 143PG. This supplies the inorganic ligand 53G to the first region formation planned region 431PG (step S67, second inorganic ligand supply step).

[0197] By supplying the inorganic ligands 53G to the first region formation planned region 431PG in this manner, the number of inorganic ligands 53G contained per unit volume in the first region formation planned region 431PG becomes greater than the number of inorganic ligands 53G contained per unit volume in the region other than the first region formation planned region 431PG. In this embodiment, the region other than the first region formation planned region 431PG in the green QD-containing layer pattern 143PG becomes the second region 432G of the EML 43G.

[0198] At least a part of the inorganic ligands 53G contained in the second inorganic ligand solution supplied to the first region-forming region 431PG is coordinated to the QDs 51G in the first region-forming region 431PG.

[0199] The second inorganic ligand solution contains the inorganic ligand 53G and a second solvent that dissolves or disperses the inorganic ligand 53G. The EML 43G is formed by removing the solvent contained in the second inorganic ligand solution applied to the first region formation planned region 431PG and drying the solution.

[0200] The second solvent may be the same as the solvent exemplified as the first solvent. The concentration of the inorganic ligand 53G in the second inorganic ligand solution and the time taken to supply the second inorganic ligand solution are not particularly limited, and may be appropriately set so that the ratio of the inorganic ligand 53G to the total number of the organic ligand 52G and the inorganic ligand 53G in the first region 431G becomes the desired ratio described above.

[0201] Furthermore, the temperature at which the second solvent is removed (in other words, the drying temperature) and the drying time are not particularly limited, and may be appropriately set so that the second solvent is removed.

[0202] As a result, an EML 43G having a first region 431G and a second region 432G is formed.

[0203] FIG. 14 is a cross-sectional view showing an example of a part of the third light-emitting layer forming step (Step S23).

[0204] In the third emitting layer forming step according to this embodiment, the third resist layer RL3 used in forming the first region 431G in the EML 43G is used as it is in forming the EML 43B as the third emitting layer without being removed.

[0205] 14, in the third light-emitting layer forming step, after the second inorganic ligand supplying step (step S67), the third resist is applied again into the opening OP4a to backfill the opening OP4a with the third resist (step S91, third resist reapplication step). As a result, a solid third resist layer RL3 covering the EML43R and EML43G is formed on the HTL42.

[0206] By filling the opening OP4a with the third resist in this manner, the third resist layer RL3 used in forming the first region 431G in the EML43G can be utilized. Therefore, it is not necessary to peel off the third resist layer RLG used in forming the first region 431G after forming the first region 431G, or to form a resist layer from scratch to form the EML43B after peeling off the third resist layer RL3. Therefore, compared to such a case, it is possible to reduce the number of times the resist is applied and peeled off.

[0207] After the third resist recoating step (step S91), the portion of the third resist layer RL3 corresponding to the region 43PB where the blue EML is to be formed is exposed and developed, whereby the third resist layer RL3 is patterned by removing the portion of the third resist layer RL3 corresponding to the region where the EML 43B as the third light emitting layer is to be formed (step S92, third resist layer second patterning step).

[0208] Here, the blue EML formation region 43PB refers to a region on the HTL 42 that is the underlayer where the EML 43B is to be formed (region where the third light-emitting layer is to be formed).

[0209] As described above, the third resist layer second patterning process (step S92) includes a third resist layer second exposure process (step S101) for exposing a portion of the third resist layer RL3 corresponding to the region 43PB where the blue EML is to be formed, and a third resist layer second development process (step S102) for developing the third resist layer RL3 with a developer.

[0210] In the third resist layer second patterning step, the third resist layer RL3 is exposed to light using a mask M5 that exposes a portion of the third resist layer RL3 corresponding to the region 43PB where the blue EML is to be formed (step S101, third resist layer third exposure step). The mask M5 has an opening (optical opening) so that the portion of the mask M5 corresponding to the region 43PB where the blue EML is to be formed has light-transmitting properties and the other portion of the mask M5 other than the region 43PB where the blue EML is to be formed has light-shielding properties.

[0211] Next, the third resist layer RL3 is developed with a developer (step S102, third resist layer second developing step). As a result, the exposed portion of the third resist layer RL3 is removed, and a third resist pattern RP3 made of the third resist layer RL3 is formed only in the portion of the HTL 42 other than the region 43PB where the blue EML is to be formed.

[0212] After the third resist layer second patterning step, the blue QD-containing layer 143B as the third QD-containing layer is formed in a solid shape covering the entirety of the subpixels SP (i.e., the entirety of the pixel region DA) (step S93, third QD-containing layer formation step). The blue QD-containing layer 143B includes QD51B as the third QD, and at least the organic ligand 52B among the organic ligand 52B as the third organic ligand and the inorganic ligand 53B as the third inorganic ligand.

[0213] Next, the third resist pattern RP3 made of the third resist layer RL3 is peeled off, for example, with the resist solvent described above, thereby lifting off the blue QD-containing layer 143B on the third resist pattern RP3, and removing the blue QD-containing layer 143B other than the blue EML formation region 43PB (step S94, third QD-containing layer patterning step).

[0214] By carrying out the above steps S91 to S94, a blue QD-containing layer pattern 143PB as a third QD-containing layer pattern made of the blue QD-containing layer 143B is formed in the blue EML formation region 43PB.

[0215] Fig. 15 is a partially enlarged cross-sectional view showing a schematic diagram of the process of forming the third light-emitting layer (step S23) subsequent to Fig. 14. For convenience of illustration, the numbers of QD51R, QD51G, QD51B, and ligands are omitted in Fig. 15.

[0216] After the third QD-containing layer patterning step, in this embodiment, as shown in Fig. 15, a fourth resist is applied to cover the entirety of the sub-pixels SP (i.e., the entirety of the pixel region DA) on the HTL42 as the underlayer so as to cover the EML43R, EML43G, and the blue QD-containing layer pattern 143PB. This forms a solid fourth resist layer RL4 on the HTL42 on which the EML43R, EML43G, and blue QD-containing layer pattern 143PB are formed (step S95, fourth resist layer formation step).

[0217] Next, the portion of the fourth resist layer RL4 corresponding to the first region formation planned region 431PB is exposed and developed. As a result, an opening OP6a (third opening) that exposes the first region formation planned region 431PB in the blue QD-containing layer pattern 143PB (i.e., the patterned blue QD-containing layer 143B) is formed in the fourth resist layer RL4 (step S96, fourth resist layer first patterning step). Here, the first region formation planned region 431PB refers to the region where the first region 431B in the EML 43B as the third light-emitting layer is finally formed.

[0218] As described above, the fourth resist layer first patterning process (step S96) includes a fourth resist layer first exposure process (step S111) of exposing a portion of the fourth resist layer RL4 corresponding to the first region formation planned area 431PB, and a fourth resist layer first development process (step S112) of developing the fourth resist layer RL4 with a developer.

[0219] In the fourth resist layer first patterning step, first, a portion of the fourth resist layer RL4 corresponding to the first region formation region 431PB is exposed using a mask M5 (step S111, fourth resist layer first exposure step).

[0220] 15 shows an example in which a positive photoresist is used for the fourth resist. Therefore, a mask that exposes a portion of the fourth resist layer RL4 corresponding to the first region formation planned region 431PB is used for the mask M6. In other words, a mask having an opening (optical opening) is used for the mask M6 so that the portion of the mask M6 corresponding to the first region formation planned region 431PB has light-transmitting properties, and the portion other than the portion corresponding to the first region formation planned region 431PB has light-shielding properties.

[0221] Next, the fourth resist layer RL4 is developed with a developer (step S112, fourth resist layer first developing step). As a result, the exposed portion of the fourth resist layer RL4 is removed, and the opening OP6a is formed in the portion of the fourth resist layer RL4 corresponding to the first region formation planned region 431PB.

[0222] In this way, by exposing and developing the portion of the fourth resist layer RL4 corresponding to the region 431PB where the first region is to be formed, and patterning the fourth resist layer RL4, it is possible to expose only the region 431PB where the first region is to be formed in the blue QD-containing layer pattern 143PB.

[0223] Therefore, after the fourth resist layer first patterning step, a third inorganic ligand solution containing an inorganic ligand 53B as a third inorganic ligand is applied to the first region formation planned region 431PB exposed from the opening OP6a in the blue QD-containing layer pattern 143PB. This supplies the inorganic ligand 53B to the first region formation planned region 431PB (step S97, third inorganic ligand supply step).

[0224] By supplying the inorganic ligands 53B to the first region-forming region 431PB in this manner, the number of inorganic ligands 53B contained per unit volume in the first region-forming region 431PB becomes greater than the number of inorganic ligands 53B contained per unit volume in the regions other than the first region-forming region 431PB. In this embodiment, the regions of the blue QD-containing layer pattern 143PB other than the first region-forming region 431PB become the second region 432B of the EML 43B.

[0225] At least a part of the inorganic ligands 53B contained in the third inorganic ligand solution supplied to the first region-forming region 431PB is coordinated to the QDs 51B in the first region-forming region 431PB.

[0226] The third inorganic ligand solution contains the inorganic ligand 53B and a third solvent that dissolves or disperses the inorganic ligand 53B. The EML 43B is formed by removing the solvent contained in the third inorganic ligand solution applied to the first region formation planned region 431PB and drying the solution.

[0227] The third solvent may be the same as the solvent exemplified as the first solvent. The concentration of the inorganic ligand 53B in the third inorganic ligand solution and the time taken to supply the third inorganic ligand solution are not particularly limited, and may be appropriately set so that the ratio of the inorganic ligand 53B to the total number of the organic ligand 52B and the inorganic ligand 53B in the first region 431B is the desired ratio described above.

[0228] Furthermore, the temperature at which the third solvent is removed (in other words, the drying temperature) and the drying time are not particularly limited, and may be appropriately set so that the third solvent is removed.

[0229] As a result, an EML 43B having a first region 431B and a second region 432B is formed.

[0230] Next, the fourth resist layer RL4 is removed by dissolving it with the resist solvent described above (step S98, fourth resist layer removal step). This makes it possible to form a plurality of island-shaped EMLs 43 on the HTL 42, including an EML 43R having a first region 431R and a second region 432R, an EML 43G having a first region 431G and a second region 432G, and an EML 43B having a first region 431B and a second region 432B.

[0231] According to this embodiment, as described above, after the first region 431 in the first light-emitting layer is formed and after the first region 431 in the second light-emitting layer is formed, the resist layer used for forming the first region 431 is not peeled off, and only the openings in the resist layer are coated with resist again to backfill the resist layers. Therefore, as described above, the number of times the resist is coated and peeled off can be reduced, and the QDs 51 in the periphery of the subpixel that are still covered with the resist layer can be protected. Note that, although the number of times the resist is coated and peeled off increases in the center of the subpixel that becomes the first region 431, the QDs 51 in the first region 431 are protected by the inorganic ligand 53 and are therefore less likely to deteriorate.

[0232] Furthermore, according to this embodiment, as described above, the first region 431 is formed for each sub-pixel SP of each color, so that different inorganic ligands 53 can be used depending on the emission color of the sub-pixel SP.

[0233] According to this embodiment, the display device 1 according to this embodiment can be manufactured by performing each process shown in Fig. 7 to Fig. 15. Note that the method for manufacturing the display device 1 according to this embodiment may further include a process of forming a sealing layer or the like on the light-emitting element layer 3 after the second electrode formation process (step S5) shown in Fig. 7.

[0234] As described above, the manufacturing method of the display device 1 according to the present embodiment includes a first electrode forming step of forming a first electrode, a functional layer forming step of forming a functional layer 33, and a second electrode forming step of forming a second electrode. The functional layer forming step also includes a light emitting layer forming step of forming an EML 43. In the light emitting layer forming step, an EML 43 having the following configuration is formed as a light emitting layer in each subpixel SP. The EML 43 formed in the light emitting layer forming step includes (1) a first region 431 including QD51, an organic ligand 52, and an inorganic ligand 53, and (2) a second region 432 including the QD51 and at least the organic ligand 52 of the organic ligand 52 and the inorganic ligand 53, and in which the number of the inorganic ligands 53 included per unit volume is smaller than the number of the inorganic ligands 53 included per unit volume of the first region 431. The first region 431 includes a center portion of the EML 43 in each subpixel SP. The second region 432 includes at least an end portion of the EML 43 of each subpixel SP adjacent to another subpixel SP.

[0235] As a result, according to this embodiment, it is possible to achieve both improved luminous efficiency by the inorganic ligand 53 and suppression of luminescence due to leakage current from adjacent subpixels SP, making it possible to narrow the spacing between the subpixels SP and providing a method for manufacturing a display device 1 with excellent display quality.

[0236] (Modification) However, the manufacturing method of the display device 1 according to the present embodiment is not limited to the above method. Fig. 16 is a cross-sectional view showing another example of a part of the third light-emitting layer forming step (step S23) according to the present embodiment. Fig. 16 is a cross-sectional view showing a step after step S93 (third QD-containing layer forming step) shown in Fig. 14.

[0237] In this modification, after step S93 (third QD-containing layer formation process) shown in Fig. 14, a fourth resist is applied to cover the entire SP of the sub-pixels (i.e., the entire pixel region DA) so as to cover the solid blue QD-containing layer 143B. This forms a solid fourth resist layer RL4 on the blue QD-containing layer 143B (step S121, fourth resist layer formation process).

[0238] Next, a portion of the fourth resist layer RL4 corresponding to the first region formation planned region 431PB is exposed and developed, thereby forming an opening OP6a (third opening) in the fourth resist layer RL4 that exposes the first region formation planned region 431PB in the blue QD-containing layer 143B (step S122, fourth resist layer first patterning step).

[0239] As described above, the fourth resist layer first patterning process (step S122) includes a fourth resist layer first exposure process (step S131) ​​for exposing a portion of the fourth resist layer RL4 corresponding to the first region formation planned area 431PB, and a fourth resist layer first development process (step S132) for developing the fourth resist layer RL4 with a developer.

[0240] In the fourth resist layer first patterning step, first, a portion of the fourth resist layer RL4 corresponding to the first region formation region 431PB is exposed using a mask M5 (step S131, fourth resist layer first exposure step).

[0241] Next, the fourth resist layer RL4 is developed with a developer (step S132, fourth resist layer first developing step). As a result, the exposed portion of the fourth resist layer RL4 is removed, and the opening OP6a is formed in the portion of the fourth resist layer RL4 corresponding to the first region formation planned region 431PB.

[0242] Note that, except for the lower layer of the fourth resist layer RL4, the operation itself is the same as step S96 in step S122, the same as step S131 in step S111, and the same as step S132 in step S112. This makes it possible to expose only the first region formation planned region 431PB in the blue QD-containing layer 143B.

[0243] Therefore, after the fourth resist layer first patterning step, a third inorganic ligand solution containing an inorganic ligand 53B as a third inorganic ligand is applied to the first region formation planned region 431PB exposed from the opening OP6a in the blue QD-containing layer 143B. This supplies the inorganic ligand 53B to the first region formation planned region 431PB (step S123, third inorganic ligand supply step).

[0244] As a result, the number of inorganic ligands 53B contained per unit volume in the first region-to-be-formed region 431PB becomes greater than the number of inorganic ligands 53B contained per unit volume in the regions other than the first region-to-be-formed region 431PB. Therefore, in this modification as well, the first region 431B is formed in the first region-to-be-formed region 431PB.

[0245] Then, also in this modification, after removing the solvent contained in the third inorganic ligand solution applied to the first region formation region 431PB and drying, the resist layer is removed with a resist solvent.

[0246] However, in this modification, after step S93, step S94 (third QD-containing layer patterning step) is not performed, and a fourth resist layer forming step (step S121) corresponding to step S95 is performed. Therefore, the third resist layer RL3 and the blue QD-containing layer 143B covering the EML 43R and EML 43G remain in the region other than the blue EML formation region 43PB.

[0247] Therefore, in this modification, the fourth resist layer RL4 is removed by the resist solvent, and the third resist layer RL3 is peeled off by the resist solvent, so that the blue QD-containing layer 143B on the third resist layer RL3 is lifted off. As a result, the blue QD-containing layer 143B in the region other than the blue EML formation region 43PB is removed (step S124, third QD-containing layer patterning process).

[0248] According to this modification, as described above, the third QD-containing layer patterning step by peeling off the third resist layer RL3 and the fourth resist layer removal step can be performed simultaneously (i.e., in the same step). Therefore, the tact time can be shortened, and the display device 1 according to the present embodiment can be manufactured more easily.

[0249] [Embodiment 2] In the first embodiment, the process of applying resist to QDs having different luminescent colors is used to reduce the number of times the resist is applied and peeled off. That is, in the first embodiment, the resist layer used in forming the first region 431 in the first luminescent layer is used to form the second luminescent layer, and the resist layer used in forming the first region 431 in the second luminescent layer is used to form the third luminescent layer. However, the manufacturing method of the display device 1 is not limited to this, and the inorganic ligand 53 may be supplied after forming the red QD-containing layer pattern 143PR, the green QD-containing layer pattern 143PG, and the blue QD-containing layer pattern 143PB, respectively.

[0250] 17 and 18 are cross-sectional views showing an example of a part of the light-emitting layer forming step (step S13) according to this embodiment. FIG. 19 is a cross-sectional view showing an enlarged schematic view of a part of the EML43 of each color according to an example of a part of the light-emitting layer forming step (step S13) according to this embodiment. FIG. 18 shows a step after FIG. 17. FIG. 19 shows a step after FIG. 18.

[0251] In this embodiment, first, steps S31 (first resist layer formation step) to S34 (first QD-containing layer patterning step) shown in Fig. 10 are performed. As a result, as shown in S34 in Fig. 10, a red QD-containing layer pattern 143PR made of a red QD-containing layer 143R is formed in the red EML formation region 43PR.

[0252] 11 and 17, a second resist is applied to cover the entirety of the sub-pixels SP (i.e., the entirety of the pixel region DA). This forms a solid second resist layer RL2 on the HTL42 on which the red QD-containing layer pattern 143PR is formed (step S35, second resist layer formation process). Up to this point, the process is the same as in the first embodiment.

[0253] In this embodiment, after the second resist layer forming step (step S34), a portion of the second resist layer RL2 corresponding to the region 43PG where the green EML is to be formed is exposed and developed as shown in Fig. 17. This removes the second resist layer RL2 from the region 43PG where the green EML is to be formed, and patterns the second resist layer RL2 (step S141, second resist layer patterning step).

[0254] As described above, the second resist layer patterning process (step S141) includes a second resist layer exposure process (step S151) for exposing a portion of the second resist layer RL2 corresponding to the green EML formation region 43PG, and a second resist layer developing process (step S152) for developing the second resist layer RL2 with a developer.

[0255] 12. Except for the fact that a red QD-containing layer pattern 143PR not provided with the first region 431R and the second region 432R is provided instead of the EML 43R, step S141 is the same as step S62 shown in Fig. 12. Therefore, in terms of the operation itself, step S141 is the same as step S62, step S151 is the same as step S71, and step S152 is the same as step S72.

[0256] Therefore, in the second resist layer exposure step (step S151), the second resist layer RL2 is exposed using a mask M3 that exposes a portion of the second resist layer RL2 corresponding to the green EML formation region 43PG. Then, in the second resist layer development step (step S152), the second resist layer RL2 is developed with a developer.

[0257] Next, the green QD-containing layer 143G is formed in a solid manner so as to cover the entirety of the sub-pixels SP (that is, the entirety of the pixel region DA) (step S142, second QD-containing layer formation step).

[0258] Next, the second resist pattern RP2 made of the second resist layer RL2 is peeled off with a resist solvent. This lifts off the green QD-containing layer 143G on the second resist pattern RP2, and removes the green QD-containing layer 143G other than the green EML formation region 43PG (step S143, second QD-containing layer patterning step). This forms a green QD-containing layer pattern 143PG made of the green QD-containing layer 143G in the green EML formation region 43PG.

[0259] Note that, again, except that the red QD-containing layer pattern 143PR is provided instead of the EML 43R, step S142 is the same as step S63, and step S143 is the same as step S64.

[0260] Next, as shown in FIG. 18, a solid third resist layer RL3 covering the entirety of the multiple subpixels SP (i.e., the entirety of the pixel region DA) is formed on the HTL42 on which the red QD-containing layer pattern 143PR and the green QD-containing layer pattern 143PG are formed (step S161, third resist layer formation process).

[0261] Next, the portion of the third resist layer RL3 corresponding to the region 43PB where the blue EML is to be formed is exposed and developed, thereby removing the third resist layer RL3 from the region 43PB where the blue EML is to be formed, and patterning the third resist layer RL3 (step S162, third resist layer patterning step).

[0262] As described above, the third resist layer patterning process (step S162) includes a third resist layer exposure process (step S171) for exposing a portion of the third resist layer RL3 corresponding to the region 43PB where the blue EML is to be formed, and a third resist layer developing process (step S172) for developing the third resist layer RL3 with a developer.

[0263] 14, except that a red QD-containing layer pattern 143PR and a green QD-containing layer pattern 143PG, which do not have the first region 431 and the second region 432, are provided instead of EML43R and EML43G. Therefore, in terms of the operation itself, step S162 is the same as step S92, step S171 is the same as step S101, and step S172 is the same as step S102.

[0264] Therefore, in the third resist layer exposure step (step S171), the third resist layer RL3 is exposed using a mask M5 that exposes a portion of the third resist layer RL3 corresponding to the region 43PB where the blue EML is to be formed. Then, in the third resist layer development step (step S172), the third resist layer RL3 is developed with a developer.

[0265] Next, the blue QD-containing layer 143B is formed in a solid manner so as to cover the entirety of the sub-pixels SP (that is, the entirety of the pixel region DA) (step S163, third QD-containing layer formation step).

[0266] Next, the third resist pattern RP3 made of the third resist layer RL3 is peeled off with a resist solvent, thereby lifting off the blue QD-containing layer 143B on the third resist pattern RP3, and removing the blue QD-containing layer 143B other than the blue EML formation region 43PB (step S164, third QD-containing layer patterning step).

[0267] Note that, again, step S163 is the same as step S93, and step S164 is the same as step S94, except that the red QD-containing layer pattern 143PR and the green QD-containing layer pattern 143PG are provided instead of EML43R and EML43G.

[0268] Next, as shown in FIG. 19, a solid fourth resist layer RL4 covering the entirety of the multiple subpixels SP (i.e., the entire pixel region DA) is formed on the HTL42 on which the red QD-containing layer pattern 143PR, the green QD-containing layer pattern 143PG, and the blue QD-containing layer pattern 143PB are formed (step S181, third resist layer formation process).

[0269] Next, the portions of the fourth resist layer RL4 corresponding to the first region formation planned region 431PR, the first region formation planned region 431PG, and the first region formation planned region 431PB are exposed and developed. As a result, openings OP7a that expose the first region formation planned region 431PR, the first region formation planned region 431PG, and the first region formation planned region 431PB are formed in the fourth resist layer RL4 (step S182, fourth resist layer patterning step).

[0270] As described above, the fourth resist layer patterning process (step S182) includes a fourth resist layer exposure process (step S191) for exposing portions of the fourth resist layer RL4 corresponding to the first region formation region 431PR, the first region formation region 431PG, and the first region formation region 431PB, and a fourth resist layer developing process (step S192) for developing the fourth resist layer RL4 with a developer.

[0271] In the fourth resist layer exposure step (step S191), a mask M7 is used to expose portions of the fourth resist layer RL4 corresponding to the first region formation region 431PR, the first region formation region 431PG, and the first region formation region 431PB.

[0272] In the fourth resist layer developing step (step S192), the exposed portion is developed and removed with a developer to form the opening OP7a on the fourth resist layer RL4, thereby exposing the first region formation planned region 431PR in the red QD-containing layer pattern 143PR, the first region formation planned region 431PG in the green QD-containing layer pattern 143PG, and the first region formation planned region 431PB in the blue QD-containing layer pattern 143PB.

[0273] After the fourth resist layer patterning step, the first region formation planned region 431PR, the first region formation planned region 431PG, and the first region formation planned region 431PB exposed from the opening OP7a are each coated with an inorganic ligand solution containing an inorganic ligand 53. This causes the inorganic ligand 53 to be supplied to the first region formation planned region 431PR, the first region formation planned region 431PG, and the first region formation planned region 431PB (step S183, inorganic ligand supplying step).

[0274] As a result, the number of inorganic ligands 53 contained per unit volume in the first region planned to be formed region 431PR, the first region planned to be formed region 431PG, and the first region planned to be formed region 431PB becomes greater than the number of inorganic ligands 53 contained per unit volume in regions other than the first region planned to be formed region 431PR, the first region planned to be formed region 431PG, and the first region planned to be formed region 431PB.

[0275] As a result, the first region 431R is formed in the first region formation region 431PR, the first region 431G is formed in the first region formation region 431PG, and the first region 431B is formed in the first region formation region 431PB. The region other than the first region formation region 431PR in the red QD-containing layer pattern 143PR becomes the second region 432R of the EML 43R. The region other than the first region formation region 431PG in the green QD-containing layer pattern 143PG becomes the second region 432G of the EML 43G. The region other than the first region formation region 431PB in the blue QD-containing layer pattern 143PB becomes the second region 432B of the EML 43B.

[0276] The inorganic ligand solution contains inorganic ligand 53 and a solvent that dissolves or disperses inorganic ligand 53. That is, in the example shown in Fig. 19, the same inorganic ligand 53 is used as inorganic ligand 53R, inorganic ligand 53G, and inorganic ligand 53B.

[0277] The solvent used for the inorganic ligand solution may be the same as the solvent exemplified as the first solvent. The concentration of the inorganic ligand 53 in the inorganic ligand solution and the time taken to supply the inorganic ligand solution are not particularly limited, and may be appropriately set so that the ratio of the inorganic ligands 53 to the total number of the organic ligands 52 and the inorganic ligands 53 in the first region 431 becomes the desired ratio described above.

[0278] Then, the solvent contained in the inorganic ligand solution applied to the first region formation region 431PR, the first region formation region 431PG, and the first region formation region 431PB is removed and dried, and then the fourth resist layer RL4 is removed with a resist solvent (step S184, fourth resist layer removal process).

[0279] This makes it possible to form multiple island-shaped EMLs 43 on the HTL 42, including an EML 43R having a first region 431R and a second region 432R, an EML 43G having a first region 431G and a second region 432G, and an EML 43B having a first region 431B and a second region 432B.

[0280] The temperature at which the solvent is removed (in other words, the drying temperature) and the drying time are not particularly limited, and may be appropriately set so that the solvent is removed.

[0281] As described above, when the same inorganic ligand 53 is used as the inorganic ligand 53R, the inorganic ligand 53G, and the inorganic ligand 53B, the inorganic ligand 53 can be supplied to the first region formation planned region 431PR, the first region formation planned region 431PG, and the first region formation planned region 431PB in parallel. This reduces the number of times the resist is applied and peeled off, shortens the takt time, and makes it easier to manufacture the display device 1 according to this embodiment.

[0282] (Variation 1) In Figure 19, as described above, an example is given of the case where inorganic ligand 53 is supplied in parallel to first region formation region 431PR, first region formation region 431PG, and first region formation region 431PB, but this embodiment is not limited to this.

[0283] For example, in step S182, an opening is formed only in the region in the fourth resist layer RL4 where the first region of the first light-emitting layer is to be formed, a first inorganic ligand solution containing a first inorganic ligand is supplied, and the opening is backfilled with the fourth resist. Then, an opening is formed only in the region in the second light-emitting layer where the first region is to be formed, a second inorganic ligand solution containing a second inorganic ligand is supplied, and the opening is backfilled with the fourth resist. Then, an opening is formed only in the positive region in the third light-emitting layer where the first region is to be formed, and a third inorganic ligand solution containing a third inorganic ligand is supplied. Finally, the fourth resist layer RL4 is removed. In this case, the first inorganic ligand solution, the second inorganic ligand solution, and the third inorganic ligand solution may be different in type or concentration from each other.

[0284] In this way, after step S164 shown in Fig. 18, steps similar to steps S35 to S37 shown in Fig. 11 may be performed, then steps similar to steps S65 to S67 shown in Fig. 13 may be performed, and then steps similar to steps S95 to S98 shown in Fig. 15 may be performed. In this case, the red QD-containing layer pattern 143PR, the green QD-containing layer pattern 143PG, and the blue QD-containing layer pattern 143PB are formed in advance on the HTL 42 as the QD-containing layer pattern, which is the same as Figs. 11, 13, and 15. For this reason, illustration is omitted in this modified example.

[0285] (Variation 2) 20 is a schematic enlarged cross-sectional view of the EML 43 of each color according to another example of a part of the light-emitting layer forming step (step S13) according to the present embodiment. Note that FIG. 20 shows a step subsequent to FIG. 18.

[0286] In this modification, step S201 shown in Fig. 20 is performed instead of steps S181 to S184 shown in Fig. 19. In this modification, as shown in Fig. 20, a metal mask M8 is used as a mask in place of a resist layer for supplying the inorganic ligand 53.

[0287] In this modification, the metal mask M8 is aligned with high precision to cover the regions (regions 432PR, 432PG, and 432PB) that will become the second region 432 in the subpixel periphery of each subpixel SP with the metal mask M8. Then, inorganic ligands 53 are supplied to the first region formation planned region 431PR, the first region formation planned region 431PG, and the first region formation planned region 431PB, which will become the first region 431. This makes it possible to form EML43R, EML43G, and EML43B shown in FIGS. 3 and 4.

[0288] In this modification, the area other than the area 431PR where the first region is to be formed in the red EML formation region 43PR becomes the area 432PR which will become the second region 432R in the EML 43R. The area other than the area 431PG where the first region is to be formed in the green EML formation region 43PG becomes the area 432PG which will become the second region 432G in the EML 43G. The area other than the area 431PB where the first region is to be formed in the blue EML formation region 43PB becomes the area 432PB which will become the second region 432B in the EML 43B.

[0289] The inorganic ligand 53 may be supplied, for example, by dropping an inorganic ligand solution containing the inorganic ligand 53, or by spray coating using a mist spraying device or the like.

[0290] 20 illustrates, as an example, a case in which inorganic ligand 53 is supplied to first region formation planned region 431PR, first region formation planned region 431PG, and first region formation planned region 431PB in parallel. However, this modification is not limited to this, and EML43R, EML43G, and EML43B may be formed, for example, as follows.

[0291] That is, for example, after step S164 shown in FIG. 18, first, a metal mask having an opening only in the first region formation planned region of the first light-emitting layer is used to supply the first inorganic ligand solution only to the first region formation planned region of the first light-emitting layer. Then, a metal mask having an opening only in the first region formation planned region of the second light-emitting layer is used to supply the second inorganic ligand solution only to the first region formation planned region of the second light-emitting layer. Next, a metal mask having an opening only in the first region formation planned region of the third light-emitting layer is used to supply the third inorganic ligand only to the first region formation planned region of the third light-emitting layer. In this case, inorganic ligand solutions of different types or concentrations can be used for the first inorganic ligand solution, the second inorganic ligand solution, and the third inorganic ligand solution.

[0292] (Variation 3) 21 is a schematic enlarged cross-sectional view of the EML 43 of each color according to another example of a part of the light-emitting layer forming step (step S13) according to the present embodiment. Note that FIG. 21 shows a step subsequent to FIG. 18.

[0293] In this modification, step S211 shown in Fig. 21 is performed instead of steps S181 to S184 shown in Fig. 19. In this modification, as shown in Fig. 21, the inorganic ligand 53 is supplied by an ink-jet method.

[0294] In this modification, inorganic ligands 53 are supplied from nozzles of an inkjet head 210 in an inkjet device to first region 431, ie, first region formation region 431PR, first region formation region 431PG, and first region formation region 431PB.

[0295] In this modification, the viscosity and the amount of dropping of the inorganic ligand solution containing the inorganic ligand 53 are adjusted to prevent the inorganic ligand solution from spreading to the region that becomes the second region 432 in the subpixel peripheral portion of the subpixel SP (i.e., the region 432PR, the region 432PG, and the region 432PB). This makes it possible to form EML43R, EML43G, and EML43B shown in FIGS. 3 and 4.

[0296] In addition, FIG. 21 also illustrates an example in which the inorganic ligand 53 is supplied to the first region formation planned region 431PR, the first region formation planned region 431PG, and the first region formation planned region 431PB in parallel. However, this modified example is not limited to this. As the inorganic ligand solution, the first inorganic ligand solution, the second inorganic ligand solution, and the third inorganic ligand solution may be used, and the supply of these inorganic ligand solutions may be delayed by a time difference, and the viscosity and the amount of the inorganic ligand solutions may be adjusted so that these inorganic ligand solutions do not spread to the portion that becomes the second region 432 in each sub-pixel SP. In this case, the first inorganic ligand solution, the second inorganic ligand solution, and the third inorganic ligand solution may be different in type or concentration from each other.

[0297] (Variation 4) FIG. 22 is a flow chart showing an example of the light emitting layer forming step (step S13) according to this modified example.

[0298] As shown in FIG. 22, in this modified example, first, a first QD dispersion liquid is prepared (step S221a) for each color of QD dispersion liquid, while a second QD dispersion liquid (step S221b), a third QD dispersion liquid (step S221c), a fourth QD dispersion liquid (step S221d), a fifth QD dispersion liquid (step S221e), and a sixth QD dispersion liquid (step S221f) are prepared.

[0299] The first QD dispersion includes the first QDs, the first organic ligand, the first inorganic ligand, and a solvent. The second QD dispersion includes the first QDs, at least the first organic ligand of the first organic ligand and the first inorganic ligand, and a solvent. The number of the first inorganic ligands contained per unit volume in the second QD dispersion is smaller than the number of the first inorganic ligands contained per unit volume in the first QD dispersion.

[0300] The third QD dispersion contains the second QD, the second organic ligand, the second inorganic ligand, and a solvent. The fourth QD dispersion contains the second QD, at least the second organic ligand of the second organic ligand and the second inorganic ligand, and a solvent. The number of the second inorganic ligands contained per unit volume in the fourth QD dispersion is less than the number of the second inorganic ligands contained per unit volume in the third QD dispersion.

[0301] The fifth QD dispersion contains the third QD, the third organic ligand, the third inorganic ligand, and a solvent. The sixth QD dispersion contains the third QD, at least the third organic ligand of the third organic ligand and the third inorganic ligand, and a solvent. The number of the third inorganic ligands contained per unit volume in the sixth QD dispersion is less than the number of the third inorganic ligands contained per unit volume in the fifth QD dispersion.

[0302] Next, the first QD dispersion is applied to the first region of the first light-emitting layer (step S222a), and the solvent is removed from the applied first QD dispersion (step S223a). Also, before, after, or in parallel with steps S222a and S223a, the second QD dispersion is applied to the second region of the first light-emitting layer (step S222b), and the solvent is removed from the applied second QD dispersion (step S223b).

[0303] Next, the third QD dispersion is applied to the region where the first region of the second light-emitting layer is to be formed (step S224a), and the solvent is removed from the applied third QD dispersion (step S225a). In addition, before, after, or in parallel with the steps S224a and S225a, the fourth QD dispersion is applied to the region where the second region of the second light-emitting layer is to be formed (step S224b), and the solvent is removed from the applied fourth QD dispersion (step S225b).

[0304] Next, the fifth QD dispersion is applied to the region where the first region of the third light-emitting layer is to be formed (step S226a), and the solvent is removed from the applied fifth QD dispersion (step S227a). In addition, before, after, or in parallel with the steps S226a and S227a, the sixth QD dispersion is applied to the region where the second region of the third light-emitting layer is to be formed (step S226b), and the solvent is removed from the applied sixth QD dispersion (step S227b).

[0305] The first to sixth QD dispersions can be applied to the respective regions by, for example, separate coating using an inkjet method.

[0306] As a result, EML43R, EML43G, and EML43B shown in FIG. 3 and FIG. 4 can be formed.

[0307] [Embodiment 3] Fig. 23 is a plan view showing an example of a schematic configuration of the sub-pixels SP in the pixel region DA of the display device 1 according to the present embodiment, and shows another example of the schematic configuration of the sub-pixels SP in the pixel region DA of the display device 1 shown in Fig. 1. Note that, for convenience of illustration, Fig. 23 omits the number of sub-pixels SP.

[0308] As shown in Figure 23, in the display device 1 of this embodiment, the second region 432 includes only the end portions of the EML43 of the subpixel SP that are adjacent to other subpixels SP, the end portions being adjacent to subpixels SP that have a different emission color from the subpixel SP.

[0309] Optical crosstalk between sub-pixels SP of the same color is less of a problem than color mixing. Therefore, as shown in FIG 23, if the second region 432 is provided at the end of the EML 43 adjacent to the sub-pixel SP emitting a different emission color, color mixing can be suppressed.

[0310] Even if the second region 432 is provided only at the end of the EML43 adjacent to a subpixel SP having a different emission color, it is desirable that the shortest distance (Δa) from the end of another subpixel SP adjacent to the second region 432 in the EML43 of the subpixel SP to the end of the first region 431 of the subpixel SP be within a range of 2.0 μm or more and 8.5 μm or less.

[0311] [Embodiment 4] Fig. 24 is a plan view showing an example of a schematic configuration of the sub-pixels SP in the pixel region DA of the display device 1 according to the present embodiment, and shows yet another example of the schematic configuration of the sub-pixels SP in the pixel region DA of the display device 1 shown in Fig. 1. Note that, for convenience of illustration, Fig. 24 omits the number of sub-pixels SP.

[0312] As shown in Figure 24, in the display device 1 of this embodiment, the second region 432 includes only the end portions of the EML43 of the subpixel SP that are adjacent to other subpixels SP, the end portions being adjacent to a subpixel SP that emits light having an emission peak wavelength shorter than the emission peak wavelength of the subpixel SP.

[0313] Generally, in a QLED (nano LED), the shorter the emission peak wavelength of the emitted color, the higher the maximum driving voltage (Vd). Therefore, if the emission peak wavelength of the subpixel SP adjacent to the subpixel SP to be emitted is longer, the subpixel SP with the shorter emission peak wavelength has difficulty emitting light due to leakage current caused by driving the subpixel SP with the longer wavelength.

[0314] As described in the first embodiment, if the emission peak wavelength (λ) of the subpixel RSP is 620 nm and Eg=2.0 eV, the emission threshold voltage of the subpixel RSP is ideally 2.0 V. If the emission peak wavelength (λ) of the subpixel GSP is 530 nm and Eg=2.3 eV, the emission threshold voltage of the subpixel GSP is ideally 2.3 V. If the emission peak wavelength (λ) of the subpixel BSP is 450 nm and Eg=2.8 eV, the emission threshold voltage of the subpixel BSP is ideally 2.8 V.

[0315] 24, the display device 1 has second regions 432R at the ends of the EML 43R of the subpixel RSP that are adjacent to the subpixel GSP and the end that is adjacent to the subpixel BSP. The EML 43G of the subpixel GSP has second regions 432G only at the end that is adjacent to the subpixel BSP. However, the EML 43B of the subpixel BSP does not have second regions 432B.

[0316] In the example shown in FIG. 24, the area in the EML 43R other than the second area 432R is the first area 431R, and the area in the EML 43G other than the second area 432G is the first area 431G.

[0317] Even if the EML43B does not include the second region 432B, color mixing in the subpixel BSP due to leakage current from the subpixel RSP and the subpixel GSP is unlikely to occur as described above. For this reason, in the EML43B, similar to the first region 431B in the first to third embodiments, the ratio of the inorganic ligands 53B to the total number of the organic ligands 52B and the inorganic ligands 53B is preferably 8.2% or more and 100% or less, more preferably 8.2% or more and 82% or less, and even more preferably 41% or more and 82% or less. In this way, in the EML43B, the number of inorganic ligands 53B per unit volume does not differ depending on the region, and the inorganic ligands 53B may be contained approximately uniformly throughout the EML43B.

[0318] (Modification) In the first to third embodiments, the EML 43 in each subpixel SP is provided with the first region 431 and the second region 432. However, as an example, as shown in FIG. 24 , in the display device 1 according to the present disclosure, it is not necessarily required that all the subpixels SP include the first region 431 and the second region 432.

[0319] In the display device 1 according to the present disclosure, the EML 43 of at least one subpixel SP among the plurality of subpixels SP includes a first region 431 and a second region 432, the first region 431 includes a central portion of the EML 43 of the at least one subpixel SP, and the second region 432 includes at least one end portion of the EML 43 of the at least one subpixel SP adjacent to other subpixels SP adjacent to the at least one subpixel SP. This makes it possible to reduce the emission of the second region 432 in the subpixel periphery of the at least one subpixel SP due to leakage current from the adjacent subpixel SP to be emitted in the at least one subpixel SP. This makes it possible to improve the emission efficiency of the inorganic ligand 53 in the at least one subpixel SP, and to suppress optical crosstalk.

[0320] 23, the second region 432 may include only an end portion of the EML43 of at least one subpixel SP that is adjacent to another subpixel SP and that has a different emission color from the at least one subpixel SP. This can reduce color mixing due to leakage current in the at least one subpixel SP.

[0321] 24, the second region 432 may include only an end portion of the EML 43 of at least one subpixel SP that is adjacent to another subpixel SP and that emits light having an emission peak wavelength shorter than the emission peak wavelength of the at least one subpixel SP. This makes it possible to achieve both high luminous efficiency and high reliability due to the inorganic ligand 53 and reduced color mixing due to leakage current in the at least one subpixel SP.

[0322] Furthermore, the second region 432 may include an end portion of the EML43 of at least one subpixel SP that is adjacent to another subpixel SP and that is adjacent to a subpixel SP having the same emission color as the at least one subpixel SP. This reduces light emission due to leakage current from the adjacent subpixel SP in the at least one subpixel SP, and enables high-definition images to be displayed. For example, in the example shown in FIG. 2, the second region 432 may include all ends of the EML43 of at least one subpixel SP that are adjacent to another subpixel SP, and may be formed to surround the first region 431.

[0323] Therefore, in the manufacturing method of the display device 1 according to the present disclosure, in the light-emitting layer forming step, an EML 43 having the following configurations (i) to (iii) may be formed as a light-emitting layer in at least one subpixel SP among the plurality of subpixels SP. (i) The EML 43 includes a first region 431 and a second region 432. (ii) The first region 431 includes a central portion of the light-emitting layer of the at least one subpixel SP. (iii) The second region 432 includes at least one end portion of the light-emitting layer of the at least one subpixel SP that is adjacent to another subpixel SP adjacent to the at least one subpixel SP. This makes it possible to manufacture a display device 1 that can improve the light-emitting efficiency of the inorganic ligand 53 in the at least one subpixel SP and suppress optical crosstalk.

[0324] [Embodiment 5] Fig. 25 is a plan view showing an example of a schematic configuration of the sub-pixels SP in the pixel region DA of the display device 1 according to the present embodiment, and shows yet another example of the schematic configuration of the sub-pixels SP in the pixel region DA of the display device 1 shown in Fig. 1. Note that, for convenience of illustration, Fig. 25 omits the number of sub-pixels SP.

[0325] The display device 1 shown in Fig. 25 has the same configuration as the display device 1 shown in Fig. 24 except for the following points. In the display device 1 shown in Fig. 25, the shortest distance (Δa) from an end of a subpixel SP having a different emission color adjacent to the second region 432 in the EML43 of the subpixel SP to an end of the first region 431 of the subpixel SP increases as the difference in band gap between the EML43 of the subpixel SP and the EML43 of the subpixel SP having a different emission color increases.

[0326] As described above, when the band gap (Eg) in the subpixel RSP is 2.0 eV, the band gap (Eg) in the subpixel GSP is 2.3 eV, and the band gap (Eg) in the subpixel BSP is 2.8 eV, the band gap difference between the subpixel RSP and the subpixel BSP is Eg(RB), and Eg(RB)=0.8 eV. Furthermore, the band gap difference between the subpixel GSP and the subpixel BSP is Eg(GB), and Eg(GB)=0.5 eV. Furthermore, the band gap difference between the subpixel RSP and the subpixel GSP is Eg(RG), and Eg(RG)=0.3 eV. Therefore, the band gap difference between the subpixels SP having different emission colors is Eg(RB)>Eg(GB)>Eg(RG).

[0327] In this case, the emission threshold voltage (Vth) varies depending on the maximum driving voltage (Vdm) (corresponding to the band gap) of the subpixel SP of each color. Therefore, Vdm-Vth varies depending on the emission color of each subpixel SP. Therefore, it is desirable to reflect the change in Vdm-Vth due to the band gap difference in the shortest distance (Δa) from the end of the subpixel SP of a different emission color adjacent to the second region 432 in the EML 43 of the subpixel SP to the end of the first region 431 of the subpixel SP.

[0328] In this embodiment, the shortest distance (Δa) is calculated by adding the band gap difference to Vdm-Vth, which was set to 1 V in formula (1) shown in embodiment 1. That is, in embodiment 1, Vdm-Vth was always set to 1 V regardless of the emission color of the subpixel SP adjacent to the subpixel SP itself, but in this embodiment, the difference in maximum driving voltage (Vdm) depending on the emission color of the subpixel SP adjacent to the subpixel SP itself is reflected.

[0329] Specifically, Vdm-Vth between the subpixel RSP and the subpixel BSP is set to Vdm-Vth=1.8 V. Furthermore, Vdm-Vth between the subpixel GSP and the subpixel BSP is set to Vdm-Vth=1.5 V. Furthermore, Vdm-Vth between the subpixel RSP and the subpixel GSP is set to Vdm-Vth=1.3 V.

[0330] The shortest distance (Δa) from the end of the subpixel BSP adjacent to the second region 432R in the EML 43R of the subpixel RSP to the end of the first region 431R of the EML 43R is defined as D RB In addition, the shortest distance (Δa) from the end of the subpixel GSP adjacent to the second region 432R in the EML 43R of the subpixel RSP to the end of the first region 431R of the EML 43R is defined as D RG In addition, the shortest distance (Δa) from the end of the subpixel BSP adjacent to the second region 432G in the EML 43G of the subpixel GSP to the end of the first region 431G of the EML 43G is defined as D GB Let us assume that.

[0331] In this case, D RG <D GB <D RB , and 2.3μm≦D RG ≦7.2μm, 2.4μm≦D GB ≦7.7μm, 2.7μm≦D RB It is preferred that it is ≦8.5 μm.

[0332] In this way, by making the above-mentioned shortest distance (Δa) larger as the difference in band gap between the EML43 of the subpixel SP itself and the EML43 of the subpixel SP with a different emission color becomes larger, color mixing can be efficiently suppressed in areas where the difference in maximum driving voltages is large.

[0333] (Modification) 25 illustrates an example in which Δa increases as the difference in band gap between the EML43 of a subpixel SP and the EML43 of a subpixel SP adjacent to the subpixel SP and having a different emission color increases in the display device 1 illustrated in FIG 24. However, the present embodiment is not limited to this.

[0334] For example, in the display device 1 shown in FIG. 2 or FIG. 23, Δa may be increased as the difference in band gap between the EML 43 of a subpixel SP and the EML 43 of an adjacent subpixel SP emitting a different emission color increases.

[0335] Furthermore, the display device 1 may be configured such that the shortest distance (Δa) from an end of a subpixel SP having a different emission color adjacent to the second region 432 in the EML43 of at least one subpixel SP to the end of the first region 431 in the EML43 of the at least one subpixel SP is larger as the band gap difference between the EML43 of the at least one subpixel SP and the EML43 of the subpixel SP having a different emission color is larger.

[0336] [Embodiment 6] Fig. 26 is a plan view showing an example of a schematic configuration of the sub-pixels SP in the pixel region DA of the display device 1 according to the present embodiment, and shows yet another example of the schematic configuration of the sub-pixels SP in the pixel region DA of the display device 1 shown in Fig. 1. Note that, for convenience of illustration, Fig. 26 omits the number of sub-pixels SP.

[0337] The display device 1 shown in Fig. 26 has the same configuration as the display device 1 shown in Fig. 2, except for the following points. As shown in Fig. 26, the display device 1 shown in Fig. 26 includes a third region 433R between the first region 431R and the second region 432R in the EML 43R of the subpixel RSP. Also, a third region 433G is provided between the first region 431G and the second region 432G in the EML 43G of the subpixel RSP. Also, a third region 433G is provided between the first region 431G and the second region 432G in the EML 43G of the subpixel RSP.

[0338] The third region 433R contains QD51R, organic ligands 52R, and inorganic ligands 53R, and the number of inorganic ligands 53R contained per unit volume is less than the number of inorganic ligands 53R contained per unit volume of the first region 431R and is greater than the number of inorganic ligands 53R contained per unit volume of the second region 432R.

[0339] The third region 433G contains QD51G, organic ligands 52G, and inorganic ligands 53G, and the number of inorganic ligands 53G contained per unit volume is less than the number of inorganic ligands 53G contained per unit volume of the first region 431G and is greater than the number of inorganic ligands 53G contained per unit volume of the second region 432G.

[0340] The third region 433B contains QDs 51B, organic ligands 52B, and inorganic ligands 53B, and the number of inorganic ligands 53B contained per unit volume is less than the number of inorganic ligands 53B contained per unit volume of the first region 431B and is greater than the number of inorganic ligands 53B contained per unit volume of the second region 432B.

[0341] In the following description, when there is no need to particularly distinguish between third region 433R, third region 433G, and third region 433B, they will be collectively referred to simply as "third region 433."

[0342] 26 illustrates an example in which the third region 433 is provided between the first region 431 and the second region 432 in the display device 1 illustrated in FIG. 2. However, the present embodiment is not limited to this example, and for example, the third region 433 may be provided between the first region 431 and the second region 432 in the display device 1 illustrated in FIG. 23, FIG. 24, or FIG. 26.

[0343] Furthermore, the display device 1 may be configured such that the third region 433 is provided between the first region 431 and the second region 432 in the EML 43 of at least one subpixel SP.

[0344] By providing the third region 433 between the first region 431 and the second region 432 in this manner, the light emitting efficiency in the peripheral region of the sub-pixel can be improved compared to when the third region 433 is not provided (in other words, when only the second region 432 is provided in the peripheral region of the sub-pixel).

[0345] Figure 27 is a graph showing the relationship between the distance x from the end of the subpixel within the subpixel SP, the amount of voltage increase v(x) of the subpixel SP due to driving of the subpixel SP to be emitted that is adjacent to the subpixel SP, and the amount of increase V(r) in the emission threshold voltage of the subpixel SP when the proportion of inorganic ligands 53 to the total number of organic ligands 52 and inorganic ligands 53 is r.

[0346] Here, the distance x from the end of the subpixel in the subpixel SP indicates the distance from the end of the subpixel SP toward the center of the subpixel SP. If the width of the second region 432 is a1 and the width of the third region 433 is a2, the voltage increase v(x) of the subpixel SP caused by driving the subpixel SP adjacent to the subpixel SP is expressed as v(x)=1×(1-x / (a1+a2)) [unit: V]. Note that a1+a2 is equal to the value obtained by subtracting the distance between the subpixels SP from Δa shown in the first embodiment.

[0347] On the other hand, when the ratio of the inorganic ligands 53 to the total number of the organic ligands 52 and the inorganic ligands 53 is r, the amount of increase V(r) in the emission threshold voltage of the subpixel SP is given by formula (2) shown in the first embodiment.

[0348] In order to prevent the second region 432 and the third region 433 from emitting light due to driving of the subpixel SP to be emitted that is adjacent to the subpixel itself, it is desirable that v(x)≦V(r) in the range of 0≦x≦(a1+a2).

[0349] The larger v(x) is, the larger the leakage current is, and the higher the luminance is. However, as shown in FIG. 27, if V(r) is equal to or greater than v(x), the voltage v(x) cannot cause the light-emitting element ES, whose luminance threshold voltage is V(r), to emit light. Therefore, if v(x)≦V(r), crosstalk between the subpixels SP is not a problem.

[0350] In this embodiment, v(x) is specified in consideration of the voltage drop between the subpixel SP adjacent to the subpixel SP to be emitting light and the subpixel SP itself. As shown in Fig. 27, v(x) drops in proportion to the reciprocal of the value obtained by subtracting the distance between the subpixels from Δa in the first embodiment. Therefore, by gradually changing the ratio r of the inorganic ligand 53 in the subpixel periphery of the subpixel SP, it is possible to suppress light emission due to leakage current from adjacent subpixels, while at the same time increasing the light emission efficiency in the subpixel periphery compared to the case where only the second region 432 is provided in the subpixel periphery.

[0351] In this embodiment, if the ratio of inorganic ligands 53 to the total number of organic ligands 52 and inorganic ligands 53 in the second region 432 is r2, the amount of increase in the light emission threshold voltage of the second region 432 is V(r2), and v(x) when x=0 is v(0), then in order for the second region 432 to not emit light due to driving of a subpixel SP adjacent to its own subpixel SP, it is desirable that the above V(r2) be v(0)≦V(r2) with respect to the above r2.

[0352] Here, v(0) is v(0)=1 V. Therefore, in order to prevent the second region 432 from emitting light due to driving of the subpixel SP adjacent to the subpixel SP itself, it is preferable that V(r2)≧1 V. Therefore, when calculating with r=r2 in the above-mentioned formula (2), it is preferable that r2≦0.41, and it is preferable that the proportion r2 of the inorganic ligand 53 in the second region 432 is 0% or more and 41% or less.

[0353] Furthermore, as described above, in the range of 0≦x≦(a1+a2), if the width of the second region 432 and the width of the third region 433 are equal and a1=a2, then if the ratio of the inorganic ligands 53 to the total number of organic ligands 52 and inorganic ligands 53 in the third region 433 is r3, the amount of increase in the light emission threshold voltage of the second region 432 is V(r3), and v(x) when x=0.5, which is the boundary position between the third region 433 and the second region 432, is v(0.5), then in order for the third region 433 to not emit light due to the driving of a subpixel SP adjacent to its own subpixel SP, it is desirable that the above V(r3) satisfies v(0.5)≦V(r3) for the above r3.

[0354] Here, v(0.5) is v(0.5)=0.5V. Therefore, in order to prevent the third region 433 from emitting light due to driving of the subpixel SP adjacent to the subpixel SP itself, it is preferable that V(r3)≧0.5V. Therefore, when calculating with r=r3 in the above-mentioned formula (2), it is preferable that r3≦0.62. Therefore, it is preferable that the proportion r3 of the inorganic ligand 53 in the third region 433 is 41% or more and 62% or less.

[0355] As described in the first embodiment, the ratio of the inorganic ligands 53 to the total number of the organic ligands 52 and the inorganic ligands 53 in the first region 431 may be 100%. However, the maximum ratio of the inorganic ligands 53 to the total number of the organic ligands 52 and the inorganic ligands 53 that is preferable for preventing aggregation of the QDs 51 is 82%.

[0356] Therefore, assuming that the ratio of the inorganic ligand 53 to the total number of the organic ligand 52 and the inorganic ligand 53 in the first region 431 is r1, as described above, r2 < r3 < r1, and r1 to r3 only need to satisfy the above-described relationship. However, r1 is preferably in the range of 62% or more and 100% or less, and more preferably in the range of 62% or more and 82% or less. Further, r3 is preferably in the range of 41% or more and 62% or less, and r2 is preferably in the range of 0% or more and 41% or less (however, r2 < r3 < r1).

[0357] The method for manufacturing the display device 1 according to the present embodiment is different from the method for manufacturing the display device 1 according to the first to fifth embodiments in that, in the light-emitting layer forming step, in at least one sub-pixel SP among the plurality of sub-pixels SP, an EML43 further including a third region 433 is formed as the light-emitting layer between the first region 431 and the second region 432.

[0358] In addition, in order to form the third region 433 between the first region 431 and the second region 432, the inorganic ligand 53 may be supplied to the third-region formation planned region in the EML43 so that r2 < r3 < r1 as described above. Here, the third-region formation planned region finally indicates the region where the third region 433 in the EML43 is formed.

[0359] In addition, as a method for supplying the inorganic ligand 53 to the third-region formation planned region in the EML43 so that r2 < r3 < r1 as described above, the same method as the method for supplying the inorganic ligand 53 to the second-region formation planned region so that r2 < r1 in the first embodiment or the second embodiment can be used.

[0360] [Embodiment 7] FIG. 28 is a cross-sectional view showing an example of the schematic configuration of the main part of the display device 1 according to the present embodiment. Note that FIG. 28 shows another example of the cross section taken along the line A-A' shown in FIG. 2.

[0361] The display device 1 shown in Figure 28 differs from the display device 1 shown in Figure 3 in that the HIL41, HTL42, and ETL44 are separated by banks 32 between the subpixels SP, and the HIL41, HTL42, and ETL44 are formed in island shapes for each subpixel SP.

[0362] In this way, even if at least one of the HIL 41 and HTL 42 and the ETL 44 is separated between the subpixels SP by the bank 32 or the like, an unexpected leak path may occur between the subpixels SP due to splashing of the material solutions of each layer onto the bank 32 or due to foreign matter on the bank 32. However, even in such a case, since at least the first region 431 and the second region 432 are formed in the EML 43, crosstalk between the subpixels SP can be reliably suppressed.

[0363] 28 shows an example in which the HIL41, HTL42, and ETL44 are formed in an island shape for each subpixel SP. However, when the display device 1 has, for example, a conventional structure as shown in FIG. 28, the ETL44 is a common layer that supplies light to all subpixels SP, and the HIL41 and HTL42 are formed in an island shape, the same effect can be obtained. When the display device 1 has, for example, an inverted structure, the HIL41 and HTL42 are a common layer that supplies light to all subpixels SP, and the ETL44 is formed in an island shape, the same effect can be obtained.

[0364] [Embodiment 8] In the above embodiment, particularly in the first and second embodiments, as shown in FIG. 4 and the like, the first region 431R, the first region 431G, and the first region 431B each contain both the organic ligand 52 and the inorganic ligand 53 as the ligand. However, as described above, the first region 431R, the first region 431G, and the first region 431B only need to contain QD51 and at least the inorganic ligand 53 among the organic ligand 52 and the inorganic ligand 53. Therefore, in the present embodiment, a case will be described in which the first region 431R, the first region 431G, and the first region 431B contain QD51 and the inorganic ligand 53, but do not contain the organic ligand 52.

[0365] 29 is a cross-sectional view showing an example of a part of the steps of the light emitting layer forming step (step S13) according to the present embodiment. FIG 29 shows a step subsequent to the fourth resist layer developing step (step S192) in the fourth resist layer patterning step (step S182) shown in FIG 19.

[0366] In the method shown in FIG. 29, after the above step S192 and before performing step S183 (inorganic ligand supplying step), the first region formation planned region 431PR, the first region formation planned region 431PG, and the first region formation planned region 431PB exposed from the opening OP7a formed in the fourth resist layer RL4 are washed with a washing liquid. This removes the organic ligand 52 contained in the first region formation planned region 431PR, the first region formation planned region 431PG, and the first region formation planned region 431PB (step S193, organic ligand removing step, washing step). Note that, hereinafter, when there is no particular need to distinguish between the first region formation planned region 431PR, the first region formation planned region 431PG, and the first region formation planned region 431PB, they will be collectively referred to simply as the "first region formation planned region 431P."

[0367] The removal rate of the organic ligand 52 can be adjusted by, for example, the cleaning time, the supply amount of the cleaning liquid, and the like. In the present embodiment, as an example, in step S193, cleaning is performed until the organic ligand 52 is completely removed. However, in step S193, only a part of the organic ligand 52 may be removed. By removing at least a part of the organic ligand 52 in this way, the number of organic ligands 52 contained per unit volume in the first region 431 can be made smaller than the number of organic ligands 52 contained per unit volume in the second region 432. This makes it possible to make the number of inorganic ligands 53G contained per unit volume in the first region 431 larger than the number of organic ligands 52 contained per unit volume in the second region 432. Therefore, by removing at least a part of the organic ligand 52 in this way, the amount of organic ligands 52 coordinated to the QD51 in the first region formation planned region 431P can be reduced, and the number of inorganic ligands 53G coordinated to the QD51 in step S183 can be increased.

[0368] The cleaning liquid may be a solvent capable of removing the organic ligand 52 contained in the first region-forming region 431P. More specifically, the cleaning liquid may be a solvent capable of dissolving the organic ligand 52 coordinated to the QD51 and dissolving the excess organic ligand 52 not coordinated to the QD51. Examples of the cleaning liquid include alcohols such as methanol and ethanol.

[0369] The waste cleaning liquid used for cleaning and containing the organic ligand 52 may be collected as necessary. The waste cleaning liquid contains only the solvent used as the cleaning liquid and the organic ligand 52. Therefore, by collecting the waste cleaning liquid, it is possible to reuse the organic ligand 52 contained in the waste cleaning liquid.

[0370] 19, an inorganic ligand solution containing an inorganic ligand 53 is applied to each of the first region formation planned regions 431P exposed from the opening OP7a. As a result, the inorganic ligand 53 is supplied to each of the first region formation planned regions 431PR, the first region formation planned regions 431PG, and the first region formation planned regions 431PB (step S183, inorganic ligand supplying step).

[0371] As a result, the first region 431R is formed in the first region formation region 431PR, the first region 431G is formed in the first region formation region 431PG, and the first region 431B is formed in the first region formation region 431PB. The region other than the first region formation region 431PR in the red QD-containing layer pattern 143PR becomes the second region 432R of the EML 43R. The region other than the first region formation region 431PG in the green QD-containing layer pattern 143PG becomes the second region 432G of the EML 43G. The region other than the first region formation region 431PB in the blue QD-containing layer pattern 143PB becomes the second region 432B of the EML 43B.

[0372] Then, the solvent contained in the inorganic ligand solution applied to the first region formation region 431PR, the first region formation region 431PG, and the first region formation region 431PB is removed and dried, and then the fourth resist layer RL4 is removed with a resist solvent (step S184, fourth resist layer removal process).

[0373] As a result, a plurality of island-shaped EMLs 43 can be formed on the HTL 42, including an EML 43R having a first region 431R and a second region 432R, an EML 43G having a first region 431G and a second region 432G, and an EML 43B having a first region 431B and a second region 432B. However, in FIG. 29, the organic ligand 52 is completely removed in step S193. Therefore, in FIG. 29, by performing steps S183 and S184 after step S193, the first region 431R, the first region 431G, and the first region 431B, which contain QDs 51 and the inorganic ligand 53 but do not contain the organic ligand 52, can be formed.

[0374] As described above, according to this embodiment, the ratio of the organic ligands 52 to the inorganic ligands 53 in the first region 431 can be easily adjusted by performing the organic ligand removal step.

[0375] (Variation 1) 30 is a cross-sectional view showing another example of a part of the steps of the light emitting layer forming step (step S13) according to the present embodiment. Fig. 30 shows a step subsequent to the fourth resist layer developing step (step S192) in the fourth resist layer patterning step (step S182) shown in Fig. 19.

[0376] 30, after step S192, an excess of inorganic ligand 53 is supplied to each of the first region formation planned regions 431P exposed from the openings OP7a formed in the fourth resist layer RL4. As a result, the organic ligand 52 in the first region formation planned regions 431P are replaced with the inorganic ligand 53 (ligand replacement) (step S231, ligand replacement step, inorganic ligand supply step).

[0377] Step S231 is the same as step S183 shown in FIG. 19, except that an inorganic ligand solution containing inorganic ligand 53 is applied (supplied) to the first region formation region 431P until all of the organic ligands 52 contained in the first region formation region 431P are ligand-substituted with inorganic ligand 53.

[0378] The organic ligand 52 has a weaker coordination force with QD51 than the inorganic ligand 53, and is more likely to come off from QD51. Therefore, in the inorganic ligand supplying step, by supplying an excess of the inorganic ligand 53 (specifically, an excess of an inorganic ligand solution) to the first region-to-be-formed region 431P, the organic ligand 52 coordinated to the QD51 in the first region-to-be-formed region 431P can be replaced with the inorganic ligand 53.

[0379] The supply amount, concentration, and time required for ligand replacement of the inorganic ligand solution may be appropriately set so that the ratio of organic ligands 52 to inorganic ligands 53 in the first region 431 is the desired ratio, and are not particularly limited.

[0380] Then, in this modified example, the solvent contained in the inorganic ligand solution applied to the first region formation planned region 431P is removed and dried, and then the fourth resist layer RL4 is removed with a resist solvent (step S184, fourth resist layer removal process).

[0381] As a result, in this modification as well, it is possible to form, for example, first regions 431R, 431G, and 431B that contain QDs 51 and inorganic ligands 53 but do not contain organic ligands 52. Of course, in this modification as well, only a portion of organic ligands 52 may be replaced with inorganic ligands 53 in step S231.

[0382] After step S231 and before step S184, a cleaning step may be performed as necessary to remove the excess inorganic ligands 53 not coordinated to QD51 and the organic ligands 52 contained in the first region formation planned region 431P by cleaning with a cleaning liquid. In this case, the cleaning liquid used in the cleaning step may be a solvent that dissolves the organic ligands 52 coordinated to QD51 and dissolves the excess organic ligands 52 and excess inorganic ligands 53 not coordinated to QD51. Examples of the cleaning liquid include alcohols such as methanol and ethanol.

[0383] As described above, according to this modified example, by supplying an inorganic ligand solution containing inorganic ligand 53 to the first region formation planned region 431P and performing ligand replacement, the ratio of organic ligand 52 to inorganic ligand 53 in the first region 431 can be easily adjusted.

[0384] (Variation 3) 29 and 30, an example has been described in which an organic ligand removal step (cleaning step) or a ligand replacement step (inorganic ligand supply step) is performed in parallel in the first region formation planned region 431PR, the first region formation planned region 431PG, and the first region formation planned region 431PB. However, this embodiment is not limited to this, and an organic ligand removal step (cleaning step) or a ligand replacement step (inorganic ligand supply step) may be performed independently in each of the first region formation planned region 431PR, the first region formation planned region 431PG, and the first region formation planned region 431PB.

[0385] For example, after step S52 shown in FIG. 11, before step S37 (first inorganic ligand supplying step), at least a part of the organic ligand 52R in the first region formation planned region 431PR may be removed in the same manner as step S193. Then, after step S82 shown in FIG. 13, before step S67 (second inorganic ligand supplying step), at least a part of the organic ligand 52G in the first region formation planned region 431PG may be removed in the same manner as step S193. Then, after step S112 shown in FIG. 15, before step S97 (third inorganic ligand supplying step), at least a part of the organic ligand 52B in the first region formation planned region 431PB may be removed in the same manner as step S193. Of course, even when a metal mask M8 is used as a mask as shown in FIG. 20, at least a part of the organic ligand 52 in the first region formation planned region 431P may be removed in the same manner as step S193 before the inorganic ligand 53 is supplied in step S201. Alternatively, instead of or in addition to the above method, when supplying the inorganic ligand 53 in steps S37, S67, S97, S201, etc., ligand substitution of the organic ligand 52 with an excess of the inorganic ligand 53 may be performed.

[0386] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. The technical scope of the present disclosure also includes embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Furthermore, new technical features can be formed by combining the technical means disclosed in the respective embodiments. [Explanation of symbols]

[0387] 1 Display device 31 Anode (1st electrode) 33 Functional Layer 43, 43B, 43G, 43R EML (light-emitting layer) 34 Cathode (second electrode) 43PR Red EML formation area (area where the first light-emitting layer is to be formed) 43PG Green EML formation area (area where the second light-emitting layer is to be formed) 43PB Blue EML formation area (area where the third light-emitting layer is to be formed) 51, 51R, 51G, 51B QD (Quantum Dot) 52, 52R, 52G, 52B Organic Ligands 53, 53R, 53G, 53B Inorganic Ligands 143R Red QD-containing layer (first quantum dot-containing layer) 143G Green QD-containing layer (second quantum dot-containing layer) 143B Blue QD-containing layer (third quantum dot-containing layer) 431, 431R, 431G, 431B 1st area 432, 432R, 432G, 432B 2nd area 433, 433R, 433G, 433B 3rd area M8 Metal Mask OP2a opening (1st opening) OP4a opening (second opening) OP6a opening (3rd opening) RL1 First resist layer RL2 Second resist layer RL3 Third resist layer RL4 Fourth resist layer SP subpixel

Claims

1. A plurality of sub-pixels are provided, Each of the sub-pixels includes a first electrode, a second electrode, and a functional layer including at least a light-emitting layer provided between the first electrode and the second electrode; The light emitting layer of at least one of the sub-pixels includes A first region including a quantum dot and at least an inorganic ligand among an organic ligand and an inorganic ligand; a second region including the quantum dots and at least the organic ligands among the organic ligands and the inorganic ligands, the number of the inorganic ligands contained per unit volume being smaller than the number of the inorganic ligands contained per unit volume of the first region; the first region includes a central portion of the light-emitting layer of the at least one sub-pixel; The display device, characterized in that the second region includes at least one of the ends of the light-emitting layer of the at least one subpixel that is adjacent to another subpixel that is adjacent to the at least one subpixel.

2. the plurality of sub-pixels include sub-pixels having different emission colors, 2. The display device according to claim 1, wherein the second region includes only an end portion of the light-emitting layer of the at least one subpixel that is adjacent to the other subpixels and has a different emission color from the at least one subpixel.

3. the plurality of sub-pixels include sub-pixels having different emission colors, 2. The display device according to claim 1, wherein the second region includes only an end portion of the light-emitting layer of the at least one subpixel that is adjacent to the other subpixels, the end portion being adjacent to a subpixel that emits light having an emission peak wavelength shorter than the emission peak wavelength of the at least one subpixel.

4. the plurality of sub-pixels include a plurality of sub-pixels having the same emission color, 2. The display device according to claim 1, wherein the second region includes an end portion of the light-emitting layer of the at least one subpixel that is adjacent to the other subpixels, the end portion being adjacent to a subpixel having the same light-emitting color as the at least one subpixel.

5. The display device according to claim 1 or 4, characterized in that the second region includes all ends of the light-emitting layer of the at least one sub-pixel that are adjacent to the other sub-pixels, and is formed to surround the first region.

6. The display device according to any one of claims 1 to 5, characterized in that the shortest distance from an end of another subpixel adjacent to the second region in the light-emitting layer of the at least one subpixel to an end of the first region in the at least one subpixel is within a range of 2.0 μm or more and 8.5 μm or less.

7. 4. The display device according to claim 2 or 3, wherein the shortest distance from an end of a subpixel having a different emission color adjacent to the second region in the light-emitting layer of the at least one subpixel to an end of the first region in the at least one subpixel is larger as the difference in band gap between the light-emitting layer of the at least one subpixel and the light-emitting layer of the subpixel having the different emission color is larger.

8. the plurality of sub-pixels include a red sub-pixel that emits red light, a green sub-pixel that emits green light, and a blue sub-pixel that emits blue light; The shortest distance from an edge of the blue subpixel adjacent to the second region in the light-emitting layer of the red subpixel to an edge of the first region in the red subpixel is defined as D ＲＢ year, The shortest distance from an edge of the green subpixel adjacent to the second region in the light-emitting layer of the red subpixel to an edge of the first region in the red subpixel is defined as D ＲＧ year, The shortest distance from an edge of the blue subpixel adjacent to the second region in the light-emitting layer of the green subpixel to an edge of the first region in the green subpixel is defined as D ＧＢ Then, D ＲＧ <D ＧＢ <D ＲＢ , and 2.3 μm≦D ＲＧ ≦7.2μm, 2.4μm≦D ＧＢ ≦7.7μm, 2.7μm≦D ＲＢ 4. The display device according to claim 3, wherein the thickness is ≦8.5 μm.

9. 9. The display device according to claim 1, wherein the inorganic ligand is an ion of a halogen atom.

10. 10. The display device according to claim 1, wherein the inorganic ligand is a fluoride ion.

11. 11. The display device according to claim 1, wherein the proportion of the inorganic ligands in the total number of the organic ligands and the inorganic ligands in the second region is 0% or more and 41% or less.

12. 12. The display device according to claim 1, wherein the proportion of the inorganic ligands in the total number of the organic ligands and the inorganic ligands in the second region is 0% or more and 8.2% or less.

13. 13. The display device according to claim 1, wherein the proportion of the inorganic ligands in the total number of the organic ligands and the inorganic ligands in the first region is 8.2% or more and 100% or less.

14. the first region comprises the organic ligand; 14. The display device according to claim 1, wherein the proportion of the inorganic ligands in the total number of the organic ligands and the inorganic ligands in the first region is 8.2% or more and 82% or less.

15. the first region comprises the organic ligand; 14. The display device according to claim 1, wherein the proportion of the inorganic ligands in the total number of the organic ligands and the inorganic ligands in the first region is 41% or more and 82% or less.

16. 13. The display device according to claim 1, wherein the first region contains only the inorganic ligand out of the organic ligand and the inorganic ligand.

17. 17. The display device according to claim 1, wherein a region other than the second region in the light-emitting layer of the at least one sub-pixel is the first region.

18. The light-emitting layer of the at least one sub-pixel comprises: a third region including the quantum dots, the organic ligands, and the inorganic ligands, the third region having a number of the inorganic ligands contained per unit volume that is less than the number of the inorganic ligands contained per unit volume of the first region and greater than the number of the inorganic ligands contained per unit volume of the second region; 17. The display device according to claim 1, wherein the third region is provided between the first region and the second region.

19. 20. The display device according to claim 18, wherein the proportion of the inorganic ligands in the total number of the organic ligands and the inorganic ligands in the third region is 41% or more and 62% or less.

20. A method for manufacturing a display device comprising a plurality of sub-pixels, each of the plurality of sub-pixels comprising a first electrode, a second electrode, and a functional layer including at least a light-emitting layer provided between the first electrode and the second electrode, comprising: a first electrode forming step of forming the first electrode; a functional layer forming step of forming the functional layer; A second electrode forming step of forming the second electrode, the functional layer forming step includes a light emitting layer forming step of forming the light emitting layer, In the light emitting layer forming step, At least one of the sub-pixels includes, as the light-emitting layer, A first region including a quantum dot and at least an inorganic ligand among an organic ligand and an inorganic ligand; a second region including the quantum dots and at least the organic ligands among the organic ligands and the inorganic ligands, the number of the inorganic ligands contained per unit volume being smaller than the number of the inorganic ligands contained per unit volume of the first region; the first region includes a central portion of the light-emitting layer of the at least one sub-pixel; A method for manufacturing a display device, characterized in that the second region forms an emitting layer that includes at least one of the ends of the emitting layer of the at least one subpixel that is adjacent to another subpixel that is adjacent to the at least one subpixel.

21. 21. The method for manufacturing a display device according to claim 20, characterized in that in the luminescent layer formation process, the inorganic ligand is supplied to a region of the luminescent layer of the at least one subpixel that becomes the first region and includes a central portion of the luminescent layer of the at least one subpixel.

22. 22. The method for manufacturing a display device according to claim 21, wherein the inorganic ligand is supplied while covering a region that becomes the second region with a metal mask.

23. 22. The method for manufacturing a display device according to claim 21, wherein the inorganic ligand is supplied by an ink-jet method.

24. 24. The method for manufacturing a display device according to claim 21, wherein in the luminescent layer formation step, the inorganic ligand is supplied in parallel to a region in the luminescent layer of at least two subpixels among the plurality of subpixels, the region being the first region and including a central portion of the luminescent layer of the at least two subpixels.

25. the plurality of sub-pixels in the display device include a first sub-pixel having a first light-emitting layer as the light-emitting layer, a second sub-pixel having a second light-emitting layer as the light-emitting layer, and a third sub-pixel having a third light-emitting layer as the light-emitting layer; the first light-emitting layer includes first quantum dots as the quantum dots, a first organic ligand as the organic ligand, and a first inorganic ligand as the inorganic ligand; the second light-emitting layer includes second quantum dots as the quantum dots, a second organic ligand as the organic ligand, and a second inorganic ligand as the inorganic ligand; the third light-emitting layer includes third quantum dots as the quantum dots, a third organic ligand as the organic ligand, and a third inorganic ligand as the inorganic ligand; The light-emitting layer forming step includes: a first light-emitting layer forming step of forming the first light-emitting layer in the first sub-pixel; a second light-emitting layer forming step of forming the second light-emitting layer in the second sub-pixel; a third light-emitting layer forming step of forming the third light-emitting layer in the third sub-pixel, The first light-emitting layer forming step includes: a first resist layer forming step of applying a first resist to entirely cover the plurality of sub-pixels to form a first resist layer; a first resist layer patterning step of exposing and developing the first resist layer to remove the first resist layer in a region where the first light emitting layer is to be formed; a first quantum dot-containing layer forming step of forming a first quantum dot-containing layer including the first quantum dots and at least the first organic ligand among the first organic ligand and the first inorganic ligand, so as to cover the entirety of the plurality of sub-pixels, after the first resist layer patterning step; a first quantum dot-containing layer patterning step of removing the first quantum dot-containing layer except for a region where the first light-emitting layer is to be formed by lifting off the first quantum dot-containing layer on the first resist layer; a second resist layer forming step of applying a second resist to cover the entirety of the plurality of sub-pixels after the first quantum dot-containing layer patterning step, to form a second resist layer; a second resist layer first patterning step of exposing and developing the second resist layer to form a first opening in the second resist layer, the first opening exposing a region including a central portion of the first quantum dot-containing layer, the region being the first region in the first light-emitting layer; A first inorganic ligand supplying step of supplying the first inorganic ligand to a region of the first quantum dot-containing layer exposed through the first opening, The second light-emitting layer forming step includes: a second resist re-coating step of re-coating the second resist into the first opening to backfill the first opening with the second resist after the first inorganic ligand supplying step; a second resist layer second patterning step of exposing and developing the second resist layer after the second resist recoating step to remove the second resist layer from a region in which a second light emitting layer is to be formed in the sub-pixel; a second quantum dot-containing layer forming step of forming a second quantum dot-containing layer including the second quantum dots and at least the second organic ligand among the second organic ligand and the second inorganic ligand, so as to cover the entirety of the plurality of sub-pixels, after the second resist layer second patterning step; 22. The method for manufacturing a display device according to claim 20, further comprising: a second quantum dot-containing layer patterning step of removing the second quantum dot-containing layer except for a region where the second light-emitting layer is to be formed by lifting off the second quantum dot-containing layer on the second resist layer.

26. The second light-emitting layer forming step includes: a third resist layer forming step of applying a third resist to cover the entirety of the plurality of sub-pixels after the second quantum dot layer patterning step to form a third resist layer; a third resist layer first patterning step of exposing and developing the third resist layer to form a second opening portion exposing a region including a central portion of the second quantum dot-containing layer, the region being the first region of the second light-emitting layer; 26. The method for manufacturing a display device according to claim 25, further comprising a second inorganic ligand supplying step of supplying the second inorganic ligand to a region of the second quantum dot-containing layer exposed through the second opening.

27. The third light-emitting layer forming step includes: a third resist re-coating step of re-coating the third resist into the second opening to backfill the second opening with the third resist after the second inorganic ligand supplying step; a third resist layer second patterning step of exposing and developing the third resist layer after the third resist recoating step, to remove the third resist layer from a region in which a third light emitting layer is to be formed in the sub-pixel; a third quantum dot-containing layer forming step of forming a third quantum dot-containing layer including the third quantum dots and at least the third organic ligand among the third organic ligand and the third inorganic ligand, so as to cover the entirety of the plurality of sub-pixels, after the third resist layer second patterning step; a third quantum dot-containing layer patterning step of removing the third quantum dot-containing layer except for a region where the third light-emitting layer is to be formed by lifting off the third quantum dot-containing layer on the third resist layer; a fourth resist layer forming step of applying a fourth resist to cover the entirety of the plurality of sub-pixels after the third quantum dot-containing layer patterning step, to form a fourth resist layer; a fourth resist layer first patterning step of exposing and developing the fourth resist layer to form a third opening portion exposing a region including a central portion of the third quantum dot-containing layer, the region being the first region of the third light-emitting layer; a third inorganic ligand supplying step of supplying the third inorganic ligand to a region of the third quantum dot-containing layer exposed through the third opening; 27. The method for manufacturing a display device according to claim 26, further comprising a fourth resist layer removing step of removing the fourth resist layer.

28. The third light-emitting layer forming step includes: a third resist re-coating step of re-coating the third resist into the second opening to backfill the second opening with the third resist after the second inorganic ligand supplying step; a third resist layer second patterning step of exposing and developing the third resist layer after the third resist recoating step, to remove the third resist layer from a region in which a third light emitting layer is to be formed in the sub-pixel; a third quantum dot-containing layer forming step of forming a third quantum dot-containing layer including the third quantum dots and at least the third organic ligand among the third organic ligand and the third inorganic ligand, so as to cover the entirety of the plurality of sub-pixels, after the third resist layer second patterning step; a fourth resist layer forming step of applying a fourth resist to cover the entirety of the plurality of sub-pixels after the third quantum dot-containing layer forming step, to form a fourth resist layer; a fourth resist layer patterning step of exposing and developing the fourth resist layer to form a third opening that exposes a region including a central portion of the third quantum dot-containing layer, the region being the first region of the third light-emitting layer; a third inorganic ligand supplying step of supplying the third inorganic ligand to a region of the third quantum dot-containing layer exposed through the third opening; 27. The method for manufacturing a display device according to claim 26, further comprising: a third quantum dot-containing layer patterning step of removing the fourth resist layer and lifting off the third quantum dot-containing layer on the third resist layer to remove the third quantum dot-containing layer except for an area where the third light-emitting layer is to be formed.

29. The light-emitting layer forming step includes: preparing a first quantum dot dispersion liquid containing the quantum dots, the organic ligand, the inorganic ligand, and a solvent; preparing a second quantum dot dispersion liquid containing the quantum dots, at least the organic ligand among the organic ligand and the inorganic ligand, and a solvent, the number of the inorganic ligands contained per unit volume being less than the number of the inorganic ligands contained per unit volume of the first quantum dot dispersion liquid; applying the first quantum dot dispersion to a region that is to become the first region and that includes a central portion of the light-emitting layer of the at least one sub-pixel; removing the solvent contained in the first quantum dot dispersion from the applied first quantum dot dispersion; applying the second quantum dot dispersion liquid to a region of the light-emitting layer of the at least one subpixel, the region including at least one end portion of the end portions of the at least one subpixel adjacent to other subpixels adjacent to the at least one subpixel; The method for manufacturing a display device according to claim 20, further comprising the step of removing the solvent contained in the second quantum dot dispersion liquid from the applied second quantum dot dispersion liquid.

30. 30. The method for manufacturing a display device according to claim 29, wherein the application of the first quantum dot dispersion liquid and the application of the second quantum dot dispersion liquid are each performed by an inkjet method.

31. In the light emitting layer forming step, At least one of the sub-pixels includes, as the light-emitting layer, Between the first region and the second region, 21. The method for manufacturing a display device according to claim 20, further comprising forming a light-emitting layer including a third region containing the quantum dots, the organic ligands, and the inorganic ligands, wherein the number of the inorganic ligands contained per unit volume is less than the number of the inorganic ligands contained per unit volume in the first region and is greater than the number of the inorganic ligands contained per unit volume in the second region.

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