Organic electroluminescent element, method for manufacturing organic electroluminescent element, organic EL display panel, method for manufacturing organic EL display panel, method for designing film thickness structure of organic electroluminescent element, and method for designing film thickness structure of organic EL display panel

Abstract

The present invention addresses the problem of providing an organic electroluminescent element or an organic EL display panel having excellent optical characteristics that do not depend on various conditions such as the thickness of an organic film, a partition material, a pixel size, a reduced-pressure drying step, and an ink composition. The present invention relates to an organic electroluminescent element having a functional film in which at least a functional layer (1) and a functional layer (2) are laminated, the value of the flatness (F) of the film in which the functional layer (1) and the functional layer (2) are laminated being greater than either the flatness (F) of the functional film (1) or the flatness (F) of the functional film (2).

Description

Technical Field

[0001] The present invention relates to an organic electroluminescent element, a method for manufacturing an organic electroluminescent element, an organic EL display panel, a method for manufacturing an organic EL display panel, a method for designing a film thickness structure of an organic electroluminescent element, and a method for designing a film thickness structure of an organic EL display panel. Background Art

[0002] As a method for manufacturing an organic electroluminescent element, a method of forming and laminating an organic material by a vacuum evaporation method is generally used. In recent years, as a manufacturing method with more excellent material use efficiency, a manufacturing method using wet film formation is actively studied. The wet film formation forms and laminates a solutionized organic material by an inkjet method or the like.

[0003] In the manufacture of an organic electroluminescent element using wet film formation, particularly an organic EL display panel including a plurality of such elements, a method has been studied in which each pixel is partitioned by a partition wall called a bank, and an ink for forming a functional film constituting the organic electroluminescent element, i.e., an organic electroluminescent element forming composition, is ejected into a minute region within the bank by an inkjet method for film formation. At this time, a technique has been proposed in which various surface modifiers are mixed into the ink to obtain a flatter film within the region surrounded by the bank.

[0004] The chromaticity of the light-emitting region in an organic electroluminescent element is sensitive to the film thickness of the functional layer. Therefore, when forming the functional layer by a wet method, it is required to eliminate the film thickness deviation of the functional layer within each element and form the functional layer flatly. In particular, since the light-emitting region where carrier recombination occurs is generated near the interface due to the energy barrier at the heterojunction interface, the shape of the organic functional layer at the light-emitting layer interface affects the light-emitting characteristics of the element.

[0005] In addition, when an organic electroluminescent element is provided for a display panel, each pixel is partitioned by a partition wall (dam) made of polyimide or the like, and the wettability of the surface of each dam is controlled by plasma treatment or the like. Generally, the surface of a liquid injected into a fine space such as a capillary tube rises or falls along the wall portion compared to the central portion due to its surface tension, forming a curved surface called a meniscus. When the injected liquid wets the wall, the meniscus is concave with respect to the horizontal plane, and when the injected liquid repels the wall, the meniscus is convex with respect to the horizontal plane. When a functional ink is ejected into each pixel of the organic electroluminescent element, a concave or convex meniscus is formed in each pixel by the combination of the functional ink and the dam. However, in a functional layer for an organic electroluminescent element with a film thickness controlled at the nanometer level, when a meniscus with a curvature larger than its film thickness is formed, a difference in film thickness occurs between the vicinity of the dam and the central portion within one pixel. As a result, there is a problem of uneven brightness or chromaticity within one pixel.

[0006] To address these problems, for example, Patent Document 1 describes mixing two solvents with different properties to improve the flatness of the film and enhance the light-emitting characteristics. In addition, Patent Document 2 describes reducing the width of the meniscus of the functional layer by adjusting the angle of the provided partition wall to increase the light-emitting area.

[0007] Thus, the purpose of patents or research on the shape of the organic thin film after wet film formation in an organic electroluminescent element is to form a flat film by various methods such as the material for the partition wall, the functional ink material, the selection of the solvent for the functional ink, and the control of the reduced-pressure drying process, thereby making the light-emitting characteristics of the organic electroluminescent element uniform. Similarly, the purpose of patents or research on the shape of the organic thin film after wet film formation in an organic electroluminescent element is to form a flat film by various methods such as the material for the partition wall, the functional ink material, the selection of the solvent for the functional ink, and the control of the reduced-pressure drying process, thereby simplifying the design of the film thickness structure for making the light-emitting characteristics of the organic electroluminescent element uniform. Prior Art Documents Patent Documents

[0008] Patent Document 1: Japanese Patent No. 5934961 Gazette Patent Document 2: Japanese Unexamined Patent Application Publication No. 2004-71432 Summary of the Invention Problems to be Solved by the Invention

[0009] However, in the case of flattening each functional layer with a single-layer film, it is necessary to select a material for the partition wall or a solvent of the functional ink, and to finely control the reduced-pressure drying process. Moreover, in an organic EL display panel including at least three organic electroluminescent elements that emit red, green, and blue light, the film thickness structure or the size of pixels is different for each color. Therefore, even if an ink that becomes flat after drying under specific conditions is developed, when the material for the partition wall or the film thickness changes, the flatness decreases, and it is necessary to design a new functional ink or to design a new functional ink and a film thickness structure. Moreover, even if an ink that becomes flat after drying under specific conditions of the film thickness structure and the size of pixels is developed, when the material for the partition wall or the film thickness changes, the flatness decreases. Therefore, when manufacturing the panel, although the same functionality is exhibited, a variety of functional inks that meet each condition need to be prepared. Even if the same functional ink can be used to form different film thickness structures, only a very limited range of film thickness structures can be selected. In addition, even for a material that exhibits good characteristics in an organic electroluminescent element manufactured by a spin coating or evaporation method that makes the shape of the organic thin film uniform during the film formation process, when applied as a functional ink, many materials are excluded due to the condition of flatness after drying. Further, even for a material that exhibits good characteristics in an organic electroluminescent element or an organic EL display panel manufactured by a spin coating or evaporation method that makes the shape of the organic thin film uniform during the film formation process, there are many cases where the film thickness structure is reexamined due to the condition of flatness.

[0010] Thus, in the case of forming a functional film that constitutes an organic electroluminescent element or an organic EL display panel by wet film formation, even if a functional ink for an organic film having a flat shape is designed, there is a problem that unevenness occurs when various conditions such as the film thickness of the organic film, the partition wall material, the size of pixels, and the reduced-pressure drying process change, and it is necessary to redesign. Moreover, in the same case, even if an organic film having a flat shape is designed, there is a problem that unevenness occurs when various conditions such as the film thickness of the organic film, the partition wall material, the size of pixels, and the reduced-pressure drying process change, and it is necessary to redesign the film thickness structure. In addition, there is a problem that the range of materials or manufacturing processes that can be used according to various conditions is limited. Further, although the same functionality is exhibited, a variety of functional inks that meet flatness need to be prepared, or even if it is assumed that the same functional ink can ensure flatness with multiple film thickness structures, the range is limited, and there is a problem that the productivity of panel manufacturing deteriorates. Further, there is a problem that a very large number of combinations must be explored when exploring a flat laminated film.

[0011] In view of the above problems, an object of the present invention is to provide an organic electroluminescent element or an organic EL display panel having excellent optical characteristics that are independent of various conditions such as the film thickness of an organic film, a partition material, a pixel size, a reduced-pressure drying process, an ink composition, and the like. Further, an object of the present invention is to provide a method for easily designing a film thickness structure of an organic electroluminescent element or an organic EL display panel having excellent optical characteristics. Technical solution for solving the problem

[0012] The present inventors newly found that when a functional film constituting an organic electroluminescent element is formed by wet film formation in a divided region surrounded by partitions, by laminating multiple non-flat functional layers in a specific combination, the film shape in the divided region surrounded by the partitions is made uniform, thereby making the unevenness of the light-emitting surface of the organic electroluminescent element uniform. Further, it was found that by using a functional ink showing the same functionality, an organic EL display panel including an organic electroluminescent element in which the unevenness of the light-emitting surface is made uniform can be produced, thus completing the present invention.

[0013] Further, the present inventors found that when a functional film constituting an organic electroluminescent element or an organic EL display panel is formed by wet film formation in a divided region surrounded by partitions, the film thickness distribution obtained by adding up the film thickness distributions of the films formed in the divided region through numerical calculation processing is the same as the laminated film thickness distribution, thus completing the present invention.

[0014] That is, the gist of the present invention is as follows.

[0015] Mode 1 of the present invention relates to an organic electroluminescent element, which is an organic electroluminescent element having a functional film in which at least a functional layer 1 and a functional layer 2 are laminated, wherein the organic electroluminescent element is provided in a divided region partitioned by partitions, wherein when a functional ink for forming the functional layer 1 is filled into the divided region in an amount required for forming the functional layer 1 and then a film is formed by reduced-pressure drying, and the film is designated as functional film 1, the average film thickness of the functional film 1 at the central portion in the divided region is thicker than the average film thickness at the partition side portion in the divided region, when a functional ink for forming the functional layer 2 is filled into the divided region in an amount required for forming the functional layer 2 and then a film is formed by reduced-pressure drying, and the film is designated as functional film 2, the average film thickness of the functional film 2 at the partition side portion in the divided region is thicker than the average film thickness at the central portion in the divided region, The central part refers to the inside of the area bounded by a closed curve determined by the locus of points at 60% of the position from the center of gravity to the partition wall when scanning the entire outer periphery of the divided area along a straight line passing through the center of gravity of the divided area. The partition wall side part refers to the outside of the area bounded by the closed curve within the divided area. Furthermore, the closed curve may or may not include a straight line part and a corner part. The flatness F of the film in which the functional layer 1 and the functional layer 2 are laminated exhibits a value greater than either the flatness F of the functional film 1 or the flatness F of the functional film 2. Among them, the flatness F is represented by the following formula: F = M / Ap × 100 (%) (In the formula, Ap represents the length of the minor axis or the major axis in the divided area, and M represents the length of the distribution part having a film thickness less than 1.05 and greater than 0.95 when the film thickness distribution measured along the minor axis or the major axis in the divided area is divided by the film thickness h at the center of the divided area.)

[0016] Mode 2 of the present invention relates to an organic electroluminescent element, which is an organic electroluminescent element in Mode 1, The functional film 1 is a film in which the thickest part of the film thickness is located in the central part of the divided area. The functional film 2 is a film in which the thickest part of the film thickness is located in an area other than the central part of the divided area.

[0017] Mode 3 of the present invention relates to an organic electroluminescent element, which is an organic electroluminescent element in Mode 1 or 2, The average film thickness of the functional film 1 is thinner than the average film thickness of the functional film 2.

[0018] Mode 4 of the present invention relates to an organic electroluminescent element, which is an organic electroluminescent element in any one of Modes 1 to 3, The functional layer 1 and the functional layer 2 are a hole injection layer or a hole transport layer.

[0019] Mode 5 of the present invention relates to an organic electroluminescent element, which is an organic electroluminescent element in any one of Modes 1 to 4, The functional layer 1 and the functional layer 2 contain a polymer compound.

[0020] Mode 6 of the present invention relates to a method for manufacturing an organic electroluminescent element in any one of Modes 1 to 5, and the method includes the following process group (ii) after the following process group (i) or includes the following process group (i) after the following process group (ii). Process group (i) sequentially includes: a process of printing functional ink for forming the functional layer 1 onto the divided area by an inkjet method; a process of subjecting the printed divided area to reduced-pressure drying in a vacuum chamber; a process of baking the dried divided area. Process group (ii) sequentially includes: a process of printing functional ink for forming the functional layer 2 onto the divided area by an inkjet method; a process of subjecting the printed divided area to reduced-pressure drying in a vacuum chamber; a process of baking the dried divided area.

[0021] Mode 7 of the present invention relates to a method, which is in the method of Mode 6, At least one of the functional ink for forming the functional layer 1 and the functional ink for forming the functional layer 2 contains two or more organic solvents, In the process group among the process groups (i) and (ii) that uses the functional ink containing two or more organic solvents, in the process of subjecting the divided area to reduced-pressure drying in a vacuum chamber, the time when the pressure reaches below the vapor pressure of the organic solvent with the lowest vapor pressure among the two or more organic solvents is 60 seconds or more and 1800 seconds or less after the start of reduced-pressure drying.

[0022] Mode 8 of the present invention relates to an organic EL display panel, which is an organic EL display panel having a plurality of divided areas partitioned by partition walls and having organic electroluminescent elements formed in the divided areas, wherein The plurality of divided areas at least have a first divided area and a second divided area, The opening areas of the organic electroluminescent elements in the first divided area and the organic electroluminescent elements in the second divided area are different from each other, The first divided area and the second divided area each independently have a functional film in which at least the functional layer 1 and the functional layer 2 are stacked, The functional material for forming the functional layer 1 in the first divided area is the same as the functional material for forming the functional layer 1 in the second divided area, The functional material for forming the functional layer 2 in the first divided area is the same as the functional material for forming the functional layer 2 in the second divided area, Any one of the first divided area and the second divided area at least satisfies the following conditions. <Condition> When the functional ink for forming the functional layer 1 is filled into the divided area in an amount required for forming the functional layer 1 and then a film is formed by reduced-pressure drying, and this film is set as the functional film 1, the average film thickness at the central part of the divided area of the functional film 1 is thicker than the average film thickness at the side part of the partition wall. The functional ink used to form the functional layer 2 is filled into the divided area in an amount required to form the functional layer 2, and then a film is formed by drying under reduced pressure. When this film is set as the functional film 2, the average film thickness of the functional film 2 at the central portion of the divided area is thinner than the average film thickness at the side portion of the partition wall. Herein, the central portion refers to the inside of the area bounded by a closed curve determined by the locus of points at 60% of the position from the center of gravity to the partition wall when scanning the entire outer periphery of the divided area with a straight line passing through the center of gravity of the divided area. In addition, the side portion of the partition wall refers to the outside of the area bounded by the closed curve within the divided area. The closed curve herein means including or not including a straight line portion and a corner portion.

[0023] Aspect 9 of the present invention relates to an organic EL display panel, which is the organic EL display panel of Aspect 8, The flatness F of the film in which the functional layer 1 and the functional layer 2 are laminated exhibits a value greater than either the flatness F of the functional film 1 or the flatness F of the functional film 2. Herein, the flatness F is represented by the following formula: F = M / Ap × 100 (%) (In the formula, Ap represents the length of the minor axis or the major axis in the divided area, and M represents the length of the distribution portion having a film thickness less than 1.05 and greater than 0.95 when the film thickness distribution measured along the minor axis or the major axis in the divided area is divided by the film thickness h at the center of the divided area).

[0024] Aspect 10 of the present invention relates to an organic EL display panel, which is the organic EL display panel of Aspect 8 or 9, The functional film 1 is a film in which the thickest portion of the film thickness is located at the central portion of the divided area. The functional film 2 is a film in which the thickest portion of the film thickness is located in an area other than the central portion of the divided area.

[0025] Aspect 11 of the present invention relates to an organic EL display panel, which is the organic EL display panel of any one of Aspects 8 to 10, The functional film 1 is a film in which the thickest portion of the film thickness is located at the central portion of the divided area. The average film thickness of the functional film 1 is thinner than the average film thickness of the functional film 2.

[0026] Aspect 12 of the present invention relates to an organic EL display panel, which is the organic EL display panel of any one of Aspects 8 to 11, The functional layer 1 and the functional layer 2 are a hole injection layer or a hole transport layer.

[0027] Embodiment 13 of the present invention relates to an organic EL display panel, which is an organic EL display panel according to any one of Embodiments 8 to 12, wherein the functional layer 1 and the functional layer 2 contain a polymer compound.

[0028] Embodiment 14 of the present invention relates to a method for manufacturing an organic EL display panel according to any one of Embodiments 8 to 13, the method including the following process group (ii) after the following process group (i) or including the following process group (i) after the following process group (ii). The process group (i) sequentially includes: a process of printing a functional ink for forming the functional layer 1 onto the divided region by an inkjet method; a process of subjecting the printed divided region to reduced-pressure drying in a vacuum chamber; and a process of baking the dried divided region. The process group (ii) sequentially includes: a process of printing a functional ink for forming the functional layer 2 onto the divided region by an inkjet method; a process of subjecting the printed divided region to reduced-pressure drying in a vacuum chamber; and a process of baking the dried divided region.

[0029] Embodiment 15 of the present invention relates to a method, which is the method of Embodiment 14, wherein at least one of the functional ink for forming the functional layer 1 and the functional ink for forming the functional layer 2 contains two or more organic solvents, in the process group (i) and the process group (ii), in the process of subjecting the divided region to reduced-pressure drying in the process group using the functional ink containing two or more organic solvents, the time when the pressure reaches lower than the vapor pressure of the organic solvent having the lowest vapor pressure among the two or more organic solvents is 60 seconds or more and 1800 seconds or less after the start of reduced-pressure drying.

[0030] Embodiment 16 of the present invention relates to a method for designing the film thickness structure of an organic electroluminescent element, which is a method for designing the film thickness structure of an organic electroluminescent element having a functional film in which at least a functional layer 1 and a functional layer 2 are stacked and disposed in a divided region partitioned by a partition wall, wherein, when stacking the functional film 1 and the functional film 2, the film thicknesses of their respective films are set to the following combination: the flatness F of the film obtained by numerically calculating and adding the film thickness distribution of the functional film 1 and the film thickness distribution of the functional film 2 is 75% or more, The functional film 1 is formed by filling the functional ink for forming the functional layer 1 into the divided area in an amount required for forming the functional layer 1, and then drying under reduced pressure; the functional film 2 is formed by filling the functional ink for forming the functional layer 2 into the divided area in an amount required for forming the functional layer 2, and then drying under reduced pressure. Among them, the flatness F is represented by the following formula: F = M / Ap × 100 (%) (In the formula, Ap represents the length of the minor axis or major axis in the divided area, and M represents the length of the distribution part with a film thickness less than 1.05 and greater than 0.95 when the film thickness distribution measured along the minor axis or major axis in the divided area is divided by the film thickness h at the center of the divided area).

[0031] Embodiment 17 of the present invention relates to a method for designing the film thickness structure of an organic electroluminescent element, which is in the method for designing the film thickness structure of the organic electroluminescent element in Embodiment 16, the flatness F presented by the film in which the functional layer 1 and the functional layer 2 are laminated is greater than any one of the flatness F of the functional film 1 and the flatness F of the functional film 2.

[0032] Embodiment 18 of the present invention relates to a method for designing the film thickness structure of an organic electroluminescent element, which is in the method for designing the film thickness structure of the organic electroluminescent element in Embodiment 16 or 17, the functional film 1 is a film in which the thickest part of the film thickness is located at the central part of the divided area, the functional film 2 is a film in which the thickest part of the film thickness is located in a region other than the central part of the divided area.

[0033] Embodiment 19 of the present invention relates to a method for designing the film thickness structure of an organic electroluminescent element, which is in the method for designing the film thickness structure of the organic electroluminescent element in any one of Embodiments 16 to 18, the average film thickness of the functional film 1 is thinner than the average film thickness of the functional film 2.

[0034] Embodiment 20 of the present invention relates to a method for designing the film thickness structure of an organic electroluminescent element, which is in the method for designing the film thickness structure of the organic electroluminescent element in any one of Embodiments 16 to 19, the functional layer 1 and the functional layer 2 are a hole injection layer or a hole transport layer.

[0035] Embodiment 21 of the present invention relates to a method for designing the film thickness structure of an organic electroluminescent element, which is in the method for designing the film thickness structure of the organic electroluminescent element in any one of Embodiments 16 to 20, The functional layer 1 and the functional layer 2 contain a polymer compound.

[0036] Embodiment 22 of the present invention relates to a method for designing the film thickness structure of an organic EL display panel, wherein, In an organic EL display panel having a plurality of divided regions partitioned by partition walls and having organic electroluminescent elements formed in the divided regions, The plurality of divided regions have at least a first divided region and a second divided region, The organic electroluminescent elements in the first divided region and the organic electroluminescent elements in the second divided region have different emission colors, wherein, Each of the divided regions independently has a functional film in which at least the functional layer 1 and the functional layer 2 are laminated, The functional material of the functional layer 1 forming the first divided region is the same as the functional material of the functional layer 1 forming the second divided region, The functional material of the functional layer 2 forming the first divided region is the same as the functional material of the functional layer 2 forming the second divided region, When the first divided region and the second divided region independently laminate the functional film 1 and the functional film 2, the film thicknesses of their respective films are set to the following combination: the flatness F of the film obtained by numerically calculating and adding the film thickness distribution of the functional film 1 and the film thickness distribution when forming the functional film 2 is 75% or more, The functional film 1 is a film formed by filling the functional ink for forming the functional layer 1 into the divided region in an amount required for forming the functional layer 1 and then drying under reduced pressure; the functional film 2 is a film formed by filling the functional ink for forming the functional layer 2 into the divided region in an amount required for forming the functional layer 2 and then drying under reduced pressure, wherein, the flatness F is represented by the following formula: F = M / Ap × 100 (%) (In the formula, Ap represents the length of the minor axis or the major axis in the divided region, and M represents the length of the distribution part having a film thickness less than 1.05 and greater than 0.95 when the film thickness distribution measured along the minor axis or the major axis in the divided region is divided by the film thickness h at the center of the divided region)

[0037] Embodiment 23 of the present invention relates to a method for designing the film thickness structure of an organic EL display panel, which is in the method for designing the film thickness structure of the organic EL display panel of Embodiment 22, The value of the flatness F of the film in which the functional layer 1 and the functional layer 2 are laminated is greater than any one of the flatness F of the functional film 1 and the flatness F of the functional film 2.

[0038] Mode 24 of the present invention relates to a method for designing the film thickness structure of an organic EL display panel, which is in the method for designing the film thickness structure of the organic EL display panel of Mode 22 or 23, The functional film 1 is a film in which the thickest part of the film thickness is located at the central part of the divided area, The functional film 2 is a film in which the thickest part of the film thickness is located in an area other than the central part of the divided area.

[0039] Mode 25 of the present invention relates to a method for designing the film thickness structure of an organic EL display panel, which is in the method for designing the film thickness structure of the organic EL display panel of any one of Modes 22 to 24, The average film thickness of the functional film 1 is thinner than the average film thickness of the functional film 2.

[0040] Mode 26 of the present invention relates to a method for designing the film thickness structure of an organic EL display panel, which is in the method for designing the film thickness structure of the organic EL display panel of any one of Modes 22 to 25, The functional layer 1 and the functional layer 2 are a hole injection layer or a hole transport layer.

[0041] Mode 27 of the present invention relates to a method for designing the film thickness structure of an organic EL display panel, which is in the method for designing the film thickness structure of the organic EL display panel of any one of Modes 22 to 26, The functional layer 1 and the functional layer 2 contain a high molecular compound.

[0042] Mode 28 of the present invention relates to an organic electroluminescent element, which is an organic electroluminescent element having at least a functional film in which a functional layer 1 and a functional layer 2 are laminated, wherein, The organic electroluminescent element is provided in a divided area partitioned by partition walls, The functional layer 1 is a layer in which the value of the following formula is the largest among the layers constituting the functional film in the layer thickness distribution measured along the short axis or the long axis of the divided area, (Average film thickness of the central part within the divided area) - (Average film thickness of the partition wall side part within the divided area) The functional layer 2 is a layer in which the value of the following formula is the largest among the layers constituting the functional film in the layer thickness distribution measured along the short axis or the long axis of the divided area, (Average film thickness of the partition wall side part within the divided area) - (Average film thickness of the central part within the divided area) Herein, the central portion refers to the inner side of the region bounded by a closed curve determined by the locus of points at 60% of the position from the center of gravity to the partition wall when scanning the entire outer periphery of the divided region along a straight line passing through the center of gravity of the divided region. The partition wall side portion refers to the outside of the region bounded by the closed curve within the divided region. Furthermore, the closed curve may or may not include a straight portion and a corner portion. The flatness F of the laminated film obtained by adding the thickness distributions of the functional layer 1 and the functional layer 2 exhibits a value greater than either the flatness F of the functional layer 1 or the flatness F of the functional layer 2. Here, the flatness F is represented by the following formula: F = M / Ap × 100 (%) (In the formula, Ap represents the length of the minor axis or the major axis in the divided region, and M represents the length of the distribution portion having a film thickness less than 1.05 and greater than 0.95 when the film thickness distribution measured along the minor axis or the major axis in the divided region is divided by the film thickness h at the center of the divided region.) Advantages of the Invention

[0043] According to the present invention, an organic electroluminescent element having excellent optical characteristics can be provided, and the optical characteristics do not depend on various conditions such as the film thickness of the organic film, the partition wall material, the pixel size, the reduced-pressure drying process, and the ink composition. Moreover, according to the present invention, an organic EL display panel having excellent optical characteristics can be provided, and the optical characteristics do not depend on various conditions such as the film thickness of the organic film, the partition wall material, the pixel size, the reduced-pressure drying process, and the ink composition, and a functional ink showing the same functionality is used.

[0044] In addition, according to the present invention, when forming a functional film constituting an organic electroluminescent element by wet film formation, even if various conditions such as the film thickness of the organic film, the partition wall material, the pixel size, the reduced-pressure drying process, and the ink composition change, an organic electroluminescent element can be manufactured without deteriorating the optical characteristics. Moreover, according to the present invention, when forming a functional film constituting an organic electroluminescent element by wet film formation, even if various conditions such as the film thickness of the organic film, the partition wall material, the pixel size, the reduced-pressure drying process, and the ink composition change, an organic EL display panel can be manufactured without deteriorating the optical characteristics by using a functional ink showing the same functionality.

[0045] Furthermore, according to the present invention, a design method for the film thickness structure of an organic electroluminescent element or an organic EL display panel having excellent optical characteristics can be provided, and the optical characteristics do not depend on various conditions such as the film thickness of the organic film, the partition wall material, the pixel size, the reduced-pressure drying process, and the ink composition. In addition, according to the present invention, in the case of forming a functional film constituting an organic electroluminescent element or an organic EL display panel by wet film formation, even when various conditions such as the film thickness of the organic film, the partition wall material, the size of the pixel, the reduced-pressure drying process, and the ink composition change, it is possible to simply design the film thickness structure of an organic electroluminescent element or an organic EL display panel having excellent optical characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a cross-sectional view schematically showing an example of the organic electroluminescent element of the present invention. Figure 2 It is a diagram showing the film thickness distribution in Reference Example 1-1. Figure 3 It is a diagram showing the film thickness distribution in Reference Example 1-2. Figure 4 It is a diagram showing the film thickness distribution in Reference Example 1-3. Figure 5 It is a diagram showing the film thickness distribution in Example 1. Figure 6 It is a diagram showing the film thickness distribution in Example 2. Figure 7 It is a diagram showing the film thickness distribution in Example 3. Figure 8 It is a diagram showing the film thickness distribution in Example 4. Figure 9 It is a diagram showing the film thickness distribution in Example 5. Figure 10 It is a diagram showing the film thickness distribution in Reference Example 2. Figure 11 It is a diagram showing the CIEx distribution of the short axis in Reference Example 2. Figure 12 It is a diagram showing the CI Ey distribution of the short axis in Reference Example 2. Figure 13 It is a diagram showing the film thickness distribution in Reference Example 3-1. Figure 14 It is a diagram showing the film thickness distribution in Reference Example 3-2. Figure 15 It is a diagram showing the film thickness distribution in Reference Example 3-3. Figure 16 It is a diagram showing the film thickness distribution in Reference Example 3-4. Figure 17 It is a diagram showing the film thickness distribution in Reference Example 3-5. Figure 18 It is a diagram showing the film thickness distribution in Reference Example 3-6. Figure 19 It is a diagram showing the film thickness distribution in Reference Example 51-1. Figure 20 It is a diagram showing the film thickness distribution in Reference Example 51-2. Figure 21 It is a diagram showing the film thickness distribution in Reference Example 51-3. Figure 22 It is a diagram showing the film thickness distribution in Reference Example 52. Figure 23 It is a diagram showing the CIEx distribution of the minor axis in Reference Example 52. Figure 24 It is a diagram showing the CI Ey distribution of the minor axis in Reference Example 52. Figure 25 It is a diagram showing the film thickness distribution in Reference Example 53-1. Figure 26 It is a diagram showing the film thickness distribution in Reference Example 53-1. Figure 27 It is a diagram showing the film thickness distribution in Reference Example 53-1. Figure 28 It is a diagram showing the film thickness distribution in Reference Example 53-2. Figure 29 It is a diagram showing the film thickness distribution in Reference Example 53-2. Figure 30 It is a diagram showing the film thickness distribution in Reference Example 53-2. Figure 31 It is a diagram showing the film thickness distribution in Reference Example 53-3. Figure 32 It is a diagram showing the film thickness distribution in Reference Example 53-3. Figure 33 It is a diagram showing the film thickness distribution in Reference Example 53-3. Explanation of Reference Numerals

[0514] 101 Substrate 102 Anode 103 Hole Injection Layer 104 Hole Transport Layer 105 Light Emitting Layer 106 Hole Blocking Layer 107 Electron Transport Layer 108 Electron Injection Layer 109 Cathode 110 Organic Electroluminescent Element Detailed Description of the Invention

[0047] Hereinafter, embodiments for implementing the present invention will be described with reference to the accompanying drawings and the like. The embodiments described below are for explaining one embodiment of the present invention and are not intended to limit or interpret the present invention. In addition, all the components described in each embodiment are not limited to those necessary for solving the technical problems of the present invention.

[0048] In addition, in this specification, when the composition of the present invention is used as an ink ejected from a nozzle of an inkjet printer or the like, it is sometimes referred to as a functional ink or simply as an ink. When the composition of the present invention is used as an ink ejected from a nozzle of an inkjet printer or the like and ejected from the nozzle and coated into an area surrounded by a partition layer, the ink in the area surrounded by the partition layer is sometimes referred to as a liquid or a liquid film, and the ink ejected from the nozzle is sometimes referred to as a droplet.

[0049] Sometimes, the liquid or liquid film whose solvent composition ratio changes due to the drying of the liquid film in the area surrounded by the partition layer (dam) and the volatilization of the solvent is also referred to as a liquid or a liquid film. The functional film obtained by coating and forming the functional ink of the present invention and drying it by volatilizing the organic solvent is referred to as a functional film or a functional layer. In addition, a film containing an organic compound and free of solvent or substantially dried by volatilizing the solvent is referred to as an organic film. The functional film is a kind of organic film.

[0050] In this specification, a dam refers to a structure in which a film formed from a photosensitive composition is patterned by a general photolithography method and formed into a film having divided minute areas (also referred to as pixels). The divided minute areas of this structure are surrounded by the walls of the dams having a certain height, and the entire area of the wall surface is referred to as the dam side surface. In addition, the photosensitive composition manufactured for the above purpose is sometimes simply referred to as a resist.

[0051] In most cases when manufacturing an organic EL display panel by a wet method, the dam has a liquid-repellent property and has a function of preventing the coated functional ink from overflowing. The resist used to manufacture such a liquid-repellent dam is sometimes referred to as a liquid-repellent resist. In addition, the film formed using this liquid-repellent resist, especially the film manufactured without using a patterning mask for exposure or development, is referred to as a liquid-repellent resist film.

[0052] In one aspect, the present invention relates to an organic electroluminescent element having a functional film in which at least a functional layer 1 and a functional layer 2 are laminated. The organic electroluminescent element is disposed in a divided region defined by partition walls. Here, a functional ink for forming the functional layer 1 is filled into the divided region in an amount required for forming the functional layer 1, and then a film is formed by drying under reduced pressure. When this film is designated as the functional film 1, the average film thickness of the functional film 1 at the central portion in the divided region is thicker than the average film thickness at the side portion adjacent to the partition walls in the divided region. A functional ink for forming the functional layer 2 is filled into the divided region in an amount required for forming the functional layer 2, and then a film is formed by drying under reduced pressure. When this film is designated as the functional film 2, the average film thickness of the functional film 2 at the side portion adjacent to the partition walls in the divided region is thicker than the average film thickness at the central portion in the divided region. The central portion refers to the inside of a region bounded by a closed curve determined by the locus of points at 60% of the distance from the center of gravity to the partition wall when scanning the entire outer periphery of the divided region along a straight line passing through the center of gravity of the divided region. The side portion adjacent to the partition walls refers to the outside of the region bounded by the closed curve within the divided region. Further, the closed curve may include a straight portion and a corner portion. The flatness F of the film laminated with the functional layer 1 and the functional layer 2 exhibits a value greater than either the flatness F of the functional film 1 or the flatness F of the functional film 2. Here, the flatness F is represented by the following formula.

[0053] F = M / Ap × 100 (%) (In the formula, Ap represents the length of the minor axis or the major axis in the divided region, and M represents the length of the distribution portion having a film thickness less than 1.05 and greater than 0.95 when the film thickness distribution measured along the minor axis or the major axis in the divided region is divided by the film thickness h at the center of the divided region.)

[0054] In this specification, the film thickness distribution refers to the distribution of the thickness of the film in the divided region with respect to the direction of the measurement axis. In addition, in this specification, the center referred to as the "center of the divided region" means the portion corresponding to a length of 5 at the center when the length of the divided region for measuring the film thickness distribution is set to 100. Further, in this specification, the length of the distribution portion refers to the length of the divided region for measuring the film thickness distribution.

[0055] In one aspect, the present invention relates to an organic EL display panel having a plurality of divided regions partitioned by partition walls, and organic electroluminescent elements formed in the divided regions. Among them, the plurality of divided regions at least have a first divided region and a second divided region. The opening areas of the organic electroluminescent elements in the first divided region and the second divided region are different from each other. The first divided region and the second divided region each independently have a functional film in which at least a functional layer 1 and a functional layer 2 are stacked. The functional material of the functional layer 1 forming the first divided region is the same as the functional material of the functional layer 1 forming the second divided region, and the functional material of the functional layer 2 forming the first divided region is the same as the functional material of the functional layer 2 forming the second divided region. Any one of the first divided region and the second divided region satisfies at least the following conditions.

[0056] <Condition> When the functional ink for forming the functional layer 1 is filled into the divided region in an amount required for forming the functional layer 1, and then a film is formed by drying under reduced pressure, and this film is set as the functional film 1, the average film thickness of the functional film 1 at the central portion of the divided region is thicker than the average film thickness at the side portion of the partition wall. When the functional ink for forming the functional layer 2 is filled into the divided region in an amount required for forming the functional layer 2, and then a film is formed by drying under reduced pressure, and this film is set as the functional film 2, the average film thickness of the functional film 2 at the central portion of the divided region is thinner than the average film thickness at the side portion of the partition wall. Here, the central portion refers to the inside of the region bounded by a closed curve determined by the locus of points at 60% of the distance from the center of gravity to the partition wall when scanning the entire outer periphery of the divided region with a straight line passing through the center of gravity of the divided region. In addition, the side portion of the partition wall refers to the outside of the region bounded by the closed curve within the divided region. The so-called closed curve may include a straight portion and a corner portion.

[0057] In one aspect, the present invention relates to a method for designing the film thickness structure of an organic electroluminescent element, which is a method for designing the film thickness structure of an organic electroluminescent element provided in a divided region partitioned by partition walls and having a functional film in which at least a functional layer 1 and a functional layer 2 are stacked. When stacking the functional film 1 and the functional film 2, the film thicknesses of their respective films are set to the following combination: the flatness F of the film obtained by numerically calculating and adding the film thickness distribution of the functional film 1 and the film thickness distribution when forming the functional film 2 is 75% or more, preferably 85% or more. The functional film 1 is a film formed by filling the functional ink for forming the functional layer 1 into the divided region in an amount required for forming the functional layer 1 and then drying under reduced pressure; the functional film 2 is a film formed by filling the functional ink for forming the functional layer 2 into the divided region in an amount required for forming the functional layer 2 and then drying under reduced pressure. Here, the flatness F is represented by the following formula.

[0058] F = M / Ap × 100(%) (In the formula, Ap represents the length of the minor axis or the major axis in the divided region, and M represents the length of the distribution portion having a film thickness less than 1.05 and greater than 0.95 when the film thickness distribution measured along the minor axis or the major axis in the divided region is divided by the film thickness h at the center of the divided region)

[0059] In one aspect, the present invention relates to a method for designing the film thickness structure of an organic EL display panel. In an organic EL display panel having a plurality of divided regions partitioned by partition walls and having organic electroluminescent elements formed in the divided regions, the plurality of divided regions at least include a first divided region and a second divided region, and the organic electroluminescent elements in the first divided region and the organic electroluminescent elements in the second divided region have different emission colors. Among them, each of the divided regions independently has a functional film in which at least a functional layer 1 and a functional layer 2 are stacked. The functional material of the functional layer 1 forming the first divided region is the same as the functional material of the functional layer 1 forming the second divided region, and the functional material of the functional layer 2 forming the first divided region is the same as the functional material of the functional layer 2 forming the second divided region. When the first divided region and the second divided region independently stack the functional film 1 and the functional film 2, the film thicknesses of their respective films are set to the following combination: the flatness F of the film obtained by numerically calculating and adding the film thickness distribution of the functional film 1 and the film thickness distribution when forming the functional film 2 is 75% or more, preferably 85% or more. The functional film 1 is a film formed by filling the functional ink for forming the functional layer 1 into the divided region in an amount required for forming the functional layer 1 and then drying under reduced pressure. The functional film 2 is a film formed by filling the functional ink for forming the functional layer 2 into the divided region in an amount required for forming the functional layer 2 and then drying under reduced pressure. Here, the flatness F is represented by the following formula.

[0060] F = M / Ap × 100 (%) (In the formula, Ap represents the length of the minor axis or the major axis in the divided region, and M represents the length of the distribution portion having a film thickness less than 1.05 and greater than 0.95 when the film thickness distribution measured along the minor axis or the major axis in the divided region is divided by the film thickness h at the center of the divided region.)

[0061] In one aspect, the present invention relates to an organic electroluminescent element having a functional film in which at least a functional layer 1 and a functional layer 2 are stacked. The organic electroluminescent element is disposed in a divided region partitioned by a partition wall. The functional layer 1 is the layer in which the value of the following formula is the largest among the layers constituting the functional film in the layer thickness distribution measured along the minor axis or the major axis of the divided region. (The average film thickness at the central portion in the divided region) - (the average film thickness at the partition wall side portion in the divided region) The functional layer 2 is the layer in which the value of the following formula is the largest among the layers constituting the functional film in the layer thickness distribution measured along the minor axis or the major axis of the divided region. (Average film thickness of the side portion of the partition wall within the partitioned area) - (Average film thickness of the central portion within the partitioned area) Here, the central portion refers to the inner side of the area bounded by a closed curve determined by the locus of points at 60% of the position from the center of gravity to the partition wall when scanning the entire outer periphery of the partitioned area with a straight line passing through the center of gravity of the partitioned area. The side portion of the partition wall refers to the outer side of the area bounded by the closed curve within the partitioned area. Further, the closed curve may include a straight portion and a corner portion. The flatness F of the stacked film obtained by adding the layer thickness distributions of the functional layer 1 and the functional layer 2 has a value greater than either the flatness F of the functional layer 1 or the flatness F of the functional layer 2. Here, the flatness F is represented by the following formula.

[0062] F = M / Ap × 100 (%) (In the formula, Ap represents the length of the minor axis or the major axis in the partitioned area, and M represents the length of the distribution portion having a film thickness less than 1.05 and greater than 0.95 when the layer thickness distribution measured along the minor axis or the major axis in the partitioned area is divided by the film thickness h at the center of the partitioned area.)

[0063] In this specification, the layer thickness distribution refers to the distribution of the thickness of this layer portion in the partitioned area with respect to the measurement axis direction.

[0064] Function layers usually formed by a wet film formation method tend to obtain a concave shape or a convex shape depending on the wettability of the functional ink to the partition wall surface. In the present invention, since a flat functional film is manufactured by combining function layers having shapes that are relatively easy to form a film, it is not necessary to finely adjust various conditions such as the film thickness of the organic film, the partition wall material, the size of the pixel, and the reduced-pressure drying process, and an organic electroluminescent element or an organic EL display panel with a uniform total film thickness can be relatively easily manufactured. In addition, for the same reason, the film thickness structure of an organic electroluminescent element or an organic EL display panel with excellent optical characteristics can be simply designed.

[0065] <Organic electroluminescent element> The organic electroluminescent element in the present invention is usually provided in a partitioned area partitioned by partition walls and has a functional film formed by laminating at least two layers.

[0066] <Organic EL display panel> The organic EL display panel in the present invention usually has an organic electroluminescent element. The organic electroluminescent element has a plurality of partitioned areas partitioned by partition walls and a functional film provided in the partitioned areas and formed by laminating at least two layers.

[0067] <Organic electroluminescent element, organic EL display panel in the film thickness structure design method> In the design method of the film thickness structure of the present invention, an organic electroluminescent element or an organic EL display panel generally has a plurality of divided regions partitioned by partition walls and a functional film provided in the divided regions and formed by laminating at least two layers. The organic EL display panel has a plurality of divided regions.

[0068] <Partition wall layer (dam)> The partition wall layer (dam) is a partition wall provided, for example, by the following process: on a glass substrate having a conductive electrode pattern, a liquid-repellent resist is coated and openings in a plurality of minute regions are provided by photolithography.

[0069] <Liquid-repellent resist> In the present invention, either a positive-type or a negative-type liquid-repellent resist can be used, but from the viewpoint of liquid repellency, a negative-type is preferred. Among negative-type liquid-repellent resists, a photosensitive composition containing (A) a photopolymerization initiator, (B) an alkali-soluble resin, (C) a photopolymerizable compound, and (D) a liquid-repellent agent is preferred.

[0070] (A) Photopolymerization initiator (A) The photopolymerization initiator is contained to absorb ultraviolet rays and promote the polymerization reaction of (C) the photopolymerizable compound. The photopolymerization initiator used in the present application is not particularly limited, but for the reason of moderately absorbing ultraviolet rays (i-line) with a wavelength of 350 to 400 nm in the light source of the exposure machine, promoting the polymerization reaction, and improving the liquid repellency, an oxime ester-based photopolymerization initiator is preferred.

[0071] For example, the photopolymerization initiators described in Japanese Patent No. 4454067, International Publication No. 2002 / 100903, International Publication No. 2012 / 45736, International Publication No. 2015 / 36910, International Publication No. 2006 / 18973, International Publication No. 2008 / 78678, Japanese Patent No. 4818458, International Publication No. 2005 / 80338, International Publication No. 2008 / 75564, International Publication No. 2009 / 131189, International Publication No. 2009 / 131189, International Publication No. 2010 / 133077, International Publication No. 2010 / 102502, International Publication No. 2012 / 68879 can be used.

[0072] In addition, the content ratio of the photopolymerization initiator is not particularly limited, but in all solid components of the lyophobic resist, it is usually 0.1% by mass or more, preferably 1% by mass or more, more preferably 2% by mass or more, still more preferably 3% by mass or more, usually 15% by mass or less, preferably 10% by mass or less, more preferably 8% by mass or less, still more preferably 5% by mass or less. By setting it to be above the lower limit value, there is a tendency to generate sufficient lyophobicity. In addition, by setting it to be below the upper limit value, there is a tendency for the developability to become good.

[0073] (B) Alkali-soluble resin As the (B) alkali-soluble resin, there is no particular limitation as long as it can be developed with an alkaline developer. As the alkali-soluble resin, various resins having a carboxyl group or a hydroxyl group can be mentioned, but from the viewpoint of excellent developability, a resin having a carboxyl group is preferred. In addition, for reasons such as good perpendicularity of the side surface of the dam, suppression of the outflow of the lyophobic agent due to the thermal melting of the dam, and easy maintenance of lyophobicity, an alkali-soluble resin having an ethylenically unsaturated group is preferred.

[0074] (B) The specific structure of the alkali-soluble resin is not particularly limited, and an epoxy (meth) acrylate resin (B1) and / or an acrylic copolymer resin (B2) are preferred. Here, the epoxy (meth) acrylate resin (B1) is a resin obtained by adding an acid or ester compound having an ethylenically unsaturated bond (ethylenic double bond) to an epoxy resin having an aromatic ring in the main chain, and further adding a polybasic acid or its acid anhydride. In addition, further, a resin obtained by reacting a compound having a further reactive functional group with the carboxyl group of the resin obtained in the above reaction is also included in the epoxy (meth) acrylate resin (B1). For example, the alkali-soluble resins described in International Publication No. 2004 / 81621, International Publication No. 2008 / 129986, International Publication No. 2008 / 153000, International Publication No. 2018 / 43746, International Publication No. 2018 / 101314, and International Publication No. 2021 / 90836 can be used.

[0075] The content ratio of the (B) alkali-soluble resin in the lyophobic resist that can be used in the present invention is not particularly limited, but in terms of all solid components, it is usually 5% by mass or more, preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, even more preferably 40% by mass or more, particularly preferably 50% by mass or more, and usually 90% by mass or less, preferably 80% by mass or less, more preferably 70% by mass or less. By setting it to be above the lower limit value, there is a tendency for the shape of the partition wall to become good. In addition, by setting it to be below the upper limit value, there is a tendency for the lyophobicity to increase.

[0076] (C) Photopolymerizable compound It is considered that the (C) photopolymerizable compound improves the curability of the resist film and the liquid repellency. The photopolymerizable compound used herein is not particularly limited to the following, but refers to a compound having one or more ethylenically unsaturated bonds in the molecule. From the viewpoints of polymerizability, crosslinkability, and the ability to widen the difference in the solubility of the developing solution between the exposed part and the unexposed part, a compound having two or more ethylenically unsaturated bonds in the molecule is preferred. In addition, a compound whose unsaturated bond is derived from a (meth)acryloyloxy group, that is, a (meth)acrylate compound is further preferred.

[0077] Examples of the photopolymerizable compound include esters formed from aliphatic polyhydroxy compounds and unsaturated carboxylic acids; esters formed from aromatic polyhydroxy compounds and unsaturated carboxylic acids; esters obtained by the esterification reaction of polyvalent hydroxy compounds such as aliphatic polyhydroxy compounds and aromatic polyhydroxy compounds with unsaturated carboxylic acids and polybasic carboxylic acids. However, from the viewpoint of liquid repellency, esters formed from aliphatic polyhydroxy compounds and unsaturated carboxylic acids are preferred. For example, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, 2-tris(meth)acryloxymethyl ethyl phthalate, pentaerythritol tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, etc. are more preferred.

[0078] The content ratio of the (C) photopolymerizable compound in the liquid repellent resist that can be used in the present invention is not particularly limited, but in all solid components, it is usually 1% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, further preferably 15% by mass or more, usually 80% by mass or less, preferably 60% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less. By setting it to be above the lower limit value, the perpendicularity of the partition wall surface during exposure tends to be good, and by setting it to be below the upper limit value, the developability tends to be good.

[0079] (D) Liquid repellent (D) The liquid repellent preferably contains a fluorine atom-containing resin, and more preferably contains a fluorine atom-containing resin having a crosslinking group. By using such a liquid repellent, the liquid repellent resist contains a fluorine atom-containing resin or a fluorine atom-containing resin having a crosslinking group. As a result, the surface of the dam can be imparted with liquid repellency, and thus the mixing of the inks in adjacent minute regions during the coating of the functional ink can be prevented.

[0080] As the crosslinking group, examples thereof include an epoxy group or an ethylenically unsaturated group, and from the viewpoint of suppressing the outflow of the liquid-repellent component of the developer, an ethylenically unsaturated group is preferred. By using a liquid-repellent agent having a crosslinking group, the crosslinking reaction on its surface can be accelerated when the formed resist film is exposed, and the liquid-repellent agent is not easily outflowed during the development process. As a result, the obtained dam can also exhibit high liquid repellency. In addition, by using a resin containing fluorine atoms, the resin containing fluorine atoms tends to be oriented along the surface of the partition wall and serves to prevent the seepage or mixing of the functional ink.

[0081] Fluorine atoms can be contained, for example, in fluoroalkyl groups, fluoroalkenyl groups, fluoroalkylene groups, etc. Among them, from the viewpoints of liquid repellency and preventing the seepage or mixing of the functional ink, fluoroalkyl groups and fluoroalkylene groups are preferred, and fluoroalkyl groups are more preferred.

[0082] In addition, the liquid-repellent agent is preferably an acrylic copolymer. By using an acrylic copolymer, it tends to prevent the seepage or mixing of the functional ink.

[0083] (D) The content ratio of the liquid-repellent agent is not particularly limited, but relative to all solid components, it is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and usually 5% by mass or less, preferably 3% by mass or less, more preferably 2% by mass or less. By setting it to be above the lower limit value, it tends to exhibit high liquid repellency. In addition, by setting it to be below the upper limit value, it tends to be able to suppress the outflow to the micro region.

[0084] (Other additives) In addition to the ethylenically unsaturated compound as the component (A), the photopolymerization initiator as the component (B), the alkali-soluble binder as the component (C), and the liquid-repellent agent as the component (D), surfactants, colorants, ultraviolet absorbers, polymerization inhibitors, antioxidants, development improvers, silane coupling agents, epoxy compounds, other resins, etc. can be appropriately incorporated.

[0085] In addition, the liquid-repellent resist can be used in a state where each component is appropriately dissolved or dispersed in a solvent. As this solvent, there is no particular limitation, and for example, the following described organic solvents can be cited. Glycol monoalkyl ethers such as propylene glycol monomethyl ether and propylene glycol monoethyl ether; Glycol dialkyl ethers such as diethylene glycol ethyl methyl ether and diethylene glycol diethyl ether; Glycol alkyl ether acetates such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, 3-methoxybutyl acetate; Glycol diacetates such as 1,3-butanediol diacetate, 1,4-butanediol diacetate, 1,6-hexanediol diacetate, etc.; Alkoxycarboxylic acids, such as ethyl acetate, propyl acetate, butyl acetate, methyl 3 - ethoxypropionate, ethyl 3 - ethoxypropionate, methyl 3 - methoxypropionate, and ethyl 3 - methoxypropionate. Among these, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, and 3 - methoxy - 1 - butyl acetate are preferred.

[0086] <Functional film> The functional film of the present invention is formed by laminating at least two layers provided in a region (also referred to as a divided region in this specification) partitioned by a partition (dam).

[0087] As the layers constituting the functional film, for example, a hole injection layer, a hole transport layer, a light - emitting layer, and an electron transport layer can be mentioned. Each layer is formed by the following method: A functional ink having at least one functional material and a solvent is filled into the region partitioned by a partition (dam), for example, by an ink - jet method, and then dried under reduced pressure.

[0088] <Functional layer 1, Functional layer 2> The organic electroluminescent element in the present invention or the organic electroluminescent element contained in the organic EL display panel of the present invention has a functional film formed by laminating at least two layers, and the functional film includes Functional layer 1 and Functional layer 2. Similarly, the organic electroluminescent element or the organic EL display panel in the design method of the present invention has a functional film formed by laminating at least two layers, and the functional film includes Functional layer 1 and Functional layer 2. Here, Functional layer 1 refers to a layer contained in the functional film, and when a film is formed by drying under reduced pressure after filling only the functional ink for forming Functional layer 1 into the divided region, it is a layer in which the average film thickness at the central part in the divided region is thicker than the average film thickness at the side part adjacent to the partition in the divided region. In addition, Functional layer 2 refers to a layer contained in the functional film, and when a film is formed by drying under reduced pressure after filling only the functional ink for forming Functional layer 2 into the divided region, it is a layer in which the average film thickness at the side part adjacent to the partition in the divided region is thicker than the average film thickness at the central part in the divided region. Functional layer 1 and Functional layer 2 are preferably a hole injection layer or a hole transport layer. In addition, Functional layer 1 and Functional layer 2 preferably contain a polymer compound. In this specification, Functional layer 1 and Functional layer 2 are sometimes collectively referred to as the functional layer only.

[0089] Here, the central part refers to the inside of a region bounded by a closed curve determined by the locus of points at 60% of the distance from the center of gravity to the partition when scanning the entire outer periphery of the divided region with a straight line passing through the center of gravity of the divided region. In addition, the side part adjacent to the partition refers to the outside of the region within the divided region and bounded by the closed curve. The so - called closed curve means that it can include a straight - line part and a corner part.

[0090] As the functional layer 1 and the functional layer 2, for example, the following combinations are included. · Functional layer 1: Hole injection layer, Functional layer 2: Hole transport layer · Functional layer 1: Hole injection layer, Functional layer 2: Light-emitting layer · Functional layer 1: Hole injection layer, Functional layer 2: Electron transport layer · Functional layer 1: Hole transport layer, Functional layer 2: Hole injection layer · Functional layer 1: Hole transport layer, Functional layer 2: Light-emitting layer · Functional layer 1: Hole transport layer, Functional layer 2: Electron transport layer · Functional layer 1: Light-emitting layer, Functional layer 2: Hole injection layer · Functional layer 1: Light-emitting layer, Functional layer 2: Hole transport layer · Functional layer 1: Light-emitting layer, Functional layer 2: Electron transport layer · Functional layer 1: Electron transport layer, Functional layer 2: Hole injection layer · Functional layer 1: Electron transport layer, Functional layer 2: Hole transport layer · Functional layer 1: Electron transport layer, Functional layer 2: Light-emitting layer

[0091] Here, the side part and the central part of the partition are defined as above. The average film thickness of the side part of the partition being thicker than the average film thickness of the central part does not necessarily mean that the film thickness becomes thicker as it gets closer to the partition wall. Therefore, the concave shape does not necessarily require the upper surface of the center of gravity of the divided area to be at the lowest position, and it can also be a concave shape where the upper surface of the part sandwiched between the center of gravity of the divided area and any partition wall is at the lowest position. Further, the concave shape does not need to gradually descend downward from the partition wall toward the center of gravity of the divided area, and it can also temporarily rise upward in the part sandwiched between the center of gravity of the divided area and the partition wall. That is, it does not necessarily require the upper surface to gently descend from the partition wall toward the center of gravity of the divided area, and the upper surface can also have some irregularities.

[0092] The shape of the divided area considers not only rectangles such as squares and rectangles, but also any shape such as polygons or ellipses. When the shape of the divided area has a major axis and a minor axis, the concave shape and the convex shape of the functional layer are evaluated by dividing them into the major axis and the minor axis. Here, the major axis refers to the longer axis in the combination of axes with the largest aspect ratio of the shape of the divided area. In addition, the minor axis refers to the shorter axis in the combination of axes with the largest aspect ratio of the shape of the divided area.

[0093] When the shape of the divided area has a major axis and a minor axis, the concave shape and the convex shape of the functional layer can consider the following combinations. · Major axis: Convex shape, Minor axis: Convex shape · Major axis: Convex shape, Minor axis: Concave shape ·Major axis: concave shape, minor axis: concave shape ·Major axis: concave shape, minor axis: convex shape

[0094] The following describes a method for determining whether the two functional layers formed by filling the functional ink for forming the functional layer into the divided area and then performing reduced-pressure drying respectively correspond to either functional layer 1 or functional layer 2 that constitutes the functional film.

[0095] When the shape of the layer on either the major axis or the minor axis of the two functional layers is the same, being convex or concave, and the shapes of the layers on the other axis are respectively convex and concave and different from each other, functional layer 1 and functional layer 2 are determined based on the different shapes of these layers.

[0096] On the other hand, when the shapes of the layers on either the major axis or the minor axis of the two functional layers are respectively convex and concave and different from each other, functional layer 1 and functional layer 2 cannot be determined by the above method. Here, the film shape of the measured functional layer has a tendency to significantly exhibit a convex or concave shape as the film thickness distribution is shorter. Through this tendency, when functional layer 1 and functional layer 2 cannot be determined by the above method, functional layer 1 and functional layer 2 are determined based on the shape of the layer on the minor axis of the two functional layers.

[0097] The following shows examples of the combinations of functional layer 1 and functional layer 2 determined based on the above method. ·Functional layer 1 (major axis: convex shape, minor axis: convex shape), functional layer 2 (major axis: convex shape, minor axis: concave shape) ·Functional layer 1 (major axis: convex shape, minor axis: convex shape), functional layer 2 (major axis: concave shape, minor axis: convex shape) ·Functional layer 1 (major axis: convex shape, minor axis: convex shape), functional layer 2 (major axis: concave shape, minor axis: concave shape) ·Functional layer 1 (major axis: convex shape, minor axis: concave shape), functional layer 2 (major axis: concave shape, minor axis: concave shape) ·Functional layer 1 (major axis: concave shape, minor axis: convex shape), functional layer 2 (major axis: convex shape, minor axis: concave shape) ·Functional layer 1 (major axis: concave shape, minor axis: convex shape), functional layer 2 (major axis: concave shape, minor axis: concave shape)

[0098] In addition, in wet film formation, in order to reduce the vibration of the ejection amount of the functional ink generated by each nozzle, there is a case where adjacent divided areas are connected in the major axis or minor axis direction via a liquid-loving area or the like. In this case, the axis in the divided area is used to judge functional layer 1 and functional layer 2 according to the film shape of the axis perpendicular to the connection direction.

[0099] When laminating a film formed by filling only the functional ink for forming the functional layer 1 into the divided area and then drying under reduced pressure and a film formed by filling only the functional ink for forming the functional layer 2 into the divided area and then drying under reduced pressure, the value of the flatness F of the film is preferably greater than the value of the flatness F of the film (functional film 1) formed by filling only the functional ink for forming the functional layer 1 into the divided area and then drying under reduced pressure and the value of the flatness F of the film (functional film 2) formed by filling only the functional ink for forming the functional layer 2 into the divided area and then drying under reduced pressure. That is, preferably, the value of the flatness F of the film in which the functional layer 1 and the functional layer 2 are laminated is greater than either the value of the flatness F of the functional film 1 or the value of the flatness F of the functional film 2.

[0100] Here, the flatness F is represented by the following formula: F = M / Ap × 100 (%) In the formula, Ap represents the length of the minor axis or the major axis in the divided area, and M represents the length of the distribution portion of the film thickness having a film thickness less than 1.05 and greater than 0.95 when the film thickness distribution measured along the minor axis or the major axis in the divided area is divided by the film thickness h at the center of the divided area.

[0101] In the formula representing the above flatness F, the film thickness distribution for obtaining M can be measured, for example, by a non-contact measuring instrument such as a probe contact type step gauge or a white interferometer. In addition, for the film thickness distribution for obtaining M, when determining the functional layer 1 and the functional layer 2 based on the shape of the layer on the minor axis of the two functional layers, the measurement is performed along the minor axis, and when determining the functional layer 1 and the functional layer 2 based on the shape of the layer on the major axis of the two functional layers, the measurement is performed along the major axis.

[0102] It should be noted that when laminating a film formed by filling only the functional ink for forming the functional layer 1 into the divided area and then drying under reduced pressure (hereinafter also referred to as "a film formed only by the ink for the functional layer 1") and a film formed by filling only the functional ink for forming the functional layer 2 into the divided area and then drying under reduced pressure (hereinafter also referred to as "a film formed only by the ink for the functional layer 2"), the flatness F of the film hardly depends on the positional relationship between the film formed only by the ink for the functional layer 1 and the film formed only by the ink for the functional layer 2. That is, even if the film formed only by the ink for the functional layer 1 is located below the film formed only by the ink for the functional layer 2, or even if the film formed only by the ink for the functional layer 2 is located below the film formed only by the ink for the functional layer 1, the flatness F of the film hardly changes. Although the reason is not certain, it is considered that the thicknesses of the functional layer 1 and the functional layer 2 are sufficiently small compared to the length scale of the opening portion, and thus hardly affect the convection in the functional ink droplets generated during the drying process that affects the film shape.

[0103] From the viewpoint of flatness, when the functional layer 1 forms a film by vacuum drying after filling only the functional ink for forming the functional layer 1 into the divided area, the layer where the thickest part of the film thickness is located at the central part of the divided area, and when the functional layer 2 forms a film by vacuum drying after filling only the functional ink for forming the functional layer 2 into the divided area, it is preferably a layer where the thickest part of the film thickness is located in an area other than the central part of the divided area. That is, the functional film 1 is a film where the thickest part of the film thickness is located at the central part of the divided area, and the functional film 2 is preferably a film where the thickest part of the film thickness is located in an area other than the central part of the divided area.

[0104] From the viewpoint of the flatness of the laminated film of the functional layer 1 and the functional layer 2, when forming a film by vacuum drying after filling only the functional ink for forming the functional layer 1 into the divided area, among the straight lines connecting the partition walls in the divided area and the partition wall closest to it at the shortest distance, it is preferably that the film thickness of the area formed by the set of the remaining 70% parts obtained by removing 15% of the length from each of the two partition walls is greater than the average film thickness of the area other than it, and more preferably that the film thickness of the area formed by the set of the remaining 80% parts obtained by removing 10% of the length from each of the two partition walls is greater than the average film thickness of the area other than it.

[0105] From the viewpoint of the flatness of the laminated film of the functional layer 1 and the functional layer 2, when forming a film by vacuum drying after filling only the functional ink for forming the functional layer 2 into the divided area, in the shape of the obtained film, the value of the tangent slope at the opening end is preferably -1.0×10 -3 Hereinafter, it is more preferably -5.0×10 -3 Hereinafter. In addition, the difference between the thinnest part at the central part and the film thickness at the opening end is preferably 30 nm or less, and more preferably 20 nm or less. Here, the opening end represents the interface where the positive electrode material is in contact with the partition wall material. In addition, as described below, the functional layer 2 is in a concave shape, so the positive and negative of the tangent slope is negative.

[0106] <Convex shape and concave shape> The film shape of the functional layer is determined by multiple main factors such as the material of the partition wall, the size of the pixel, the film thickness of the organic film, the solvent of the functional ink, the solute of the functional ink, the drying process, and the temperature. If one condition changes, the film shape of the functional layer also changes, but by fixing other conditions, it is also possible to selectively produce a convex film shape and a concave film shape.

[0107] (Low molecular mixing amount and film shape) When forming a film by coating ink on an area divided by dams (partition walls) using a wet film-forming method, usually an adequate amount of ink is coated to wet the entire area of the divided region, and then various drying methods such as vacuum drying are used to volatilize the solvent component to obtain a functional layer. When drying the ink within the divided region, the end of the ink gradually recedes on the side of the dam, and the concentration gradually increases, finally forming a functional layer. At this time, due to the self-pinning phenomenon that sometimes occurs midway on the side of the dam caused by differences in the wettability of the dam side and shape changes of the dam side, the end of the ink may not be able to recede on the side of the dam.

[0108] Thus, when self-pinning occurs midway on the side of the dam, the formed functional layer exhibits a shape that wets and climbs along the side of the dam. That is, it is easy to form functional layer 2. On the other hand, when the self-pinning phenomenon does not occur in the early stage of drying and the side of the dam is fixed at a position equal to or lower than the height of the average film thickness at the center during drying, the formed functional layer exhibits a shape with a thicker average film thickness at the center and a thinner thickness near the partition wall. That is, it is easy to form functional layer 1. As one of the main reasons for the self-pinning phenomenon, it can be cited that the fluidity is hindered due to thickening caused by an increase in the ink concentration existing during the drying process near the partition wall. Therefore, in the case of using a functional ink such as a polymer whose viscosity easily increases as the concentration increases when drawing a viscosity-concentration curve, self-pinning due to thickening is likely to occur during the drying process, and thus it is easy to form functional layer 2. On the other hand, in the case of an ink containing a low molecule that is not easily thickened during the drying process, it is easy to form functional layer 1.

[0109] From the perspective of such a self-pinning phenomenon, by selecting the materials contained in the functional ink for the functional layer, it is also possible to selectively separate and fabricate the film shape of the functional layer within a certain range. For example, as one mode, the solute of the functional ink for forming functional layer 1 preferably contains a low molecule with a molecular weight of 2000 or less, more preferably contains 5 wt% or more. In addition, as one mode, the solute of the functional ink for forming functional layer 2 preferably contains 95 wt% or less of a low molecule with a molecular weight of 2000 or less, more preferably contains 90 wt% or less, and further preferably contains 85 wt% or less.

[0110] As a result of the above selection of the materials contained in the functional ink, as one mode, functional layer 1 preferably contains a low molecule with a molecular weight of 2000 or less, more preferably contains 5 wt% or more. In addition, as one mode, functional layer 2 preferably contains 95 wt% or less of a low molecule with a molecular weight of 2000 or less, more preferably contains 90 wt% or less, and further preferably contains 85 wt% or less.

[0111] (Self-pinning and film shape) During the drying process of a functional ink composed of multiple solvents, in the high-concentration region where self-fixation is likely to occur, the solvent mainly consists of high-boiling-point solvents. A low viscosity in such high-boiling-point solvents means that the liquid flows easily, effectively suppressing self-fixation. In addition, the higher the boiling point of the high-boiling-point solvent, the slower the drying, so that the time for the functional ink to recede on the partition can be obtained, thereby suppressing self-fixation. When self-fixation is suppressed, the film of the functional layer is convex in shape, and it is easy to form functional layer 1. On the other hand, when the viscosity of the high-boiling-point solvent that is dominant in the high-concentration region is high and the vapor pressure is high, self-fixation is likely to occur, so the film of the functional layer is concave in shape, and it is easy to form functional layer 2.

[0112] The A value represented by the following formula (Japanese Patent Application No. 2021-178216) can be used to predict the self-fixation position of a functional ink containing multiple solvents. A = γ1 × η1 / (T1 - T2) Here, γ1 represents the surface tension (mN / m) of the first solvent, η1 represents the viscosity (mPa·s) of the first solvent, T1 represents the boiling point (°C) of the first solvent under atmospheric pressure, and T2 represents the boiling point (°C) of the second solvent under atmospheric pressure. When there are multiple first solvents or second solvents, the surface tension, viscosity, and boiling point are mass-averaged.

[0113] The mass average refers to the weighted sum average based on the mass percentage of the contained solvents. For example, when taking viscosity as an example, it is represented by the following general formula. η ave = Σ n (η n × W n ) / 100

[0114] Here, η ave represents the mass average of viscosity, n is an integer and only exists from 1 to the corresponding number of multiple solvents, η n represents the viscosity of the nth solvent among the corresponding multiple solvents, W n represents the content rate (mass%) of the nth solvent among the corresponding solvents, Σ n means just adding the subsequent in-bracket expressions corresponding to the number of solvents.

[0115] In the case of multiple solvents with a boiling point of 270 °C or higher and a content less than 10 mass%, when the combined content is greater than 10 mass%, the combined mixed solvent is used as the first solvent, and the surface tension, viscosity, and boiling point are set as mass averages. In the case of multiple solvents with a boiling point lower than 270 °C and a content less than 30 mass%, when the combined content is greater than 30 mass%, the combined mixed solvent is used as the second solvent, and the surface tension, viscosity, and boiling point are set as mass averages.

[0116] As described above, by suppressing self-fixation by reducing the value of A, the wetting climb on the side of the partition can be reduced, and by using such adjusted functional ink, the film can easily form a convex-shaped layer (functional layer 1). In addition, by increasing the value of A, self-fixation becomes easier, and by using such adjusted functional ink, the film can easily form a concave-shaped layer (functional layer 2).

[0117] From the viewpoint of the shape of the functional film, the A value of the functional ink for forming the functional layer 1 is preferably smaller than the A value of the functional ink for forming the functional layer 2.

[0118] (Film thickness and film shape) When using one functional ink to form multiple functional layers with different film thicknesses, the greater the desired film thickness of the functional layer, the more the number of ink drops necessarily increases. When the height of the partition wall is the same, during the vacuum drying process, the viscosity when the liquid level reaches a specific height is higher as the number of drops increases. Therefore, if the average film thickness after film formation becomes thinner, there is a tendency to exhibit a convex shape (functional layer 1), and if it becomes thicker, there is a tendency to exhibit a concave shape (functional layer 2).

[0119] From such a viewpoint, it is preferable that the average film thickness of the film formed by vacuum drying after filling only the functional ink for forming the functional layer 1 into the divided area is thinner than the average film thickness of the film formed by vacuum drying after filling only the functional ink for forming the functional layer 2 into the divided area. That is, it is preferable that the average film thickness of the functional film 1 is thinner than the average film thickness of the functional film 2.

[0120] (Marangoni convection and film shape) The main reasons for the flow inside the droplets during the drying process are the flow from the uneven evaporation rate distribution, the flow from the change in contact angle, and the flow caused by the distribution of surface tension. As one of the factors, Marangoni convection plays an important role (H. Ishizuka, J. Fukai, Experiments in Fluids, 59, 4, 1-11, 2018) (J. Fukai, T. Harada, H. Ishizuka, Journal of Chemical Engineering of Japan, 52, 6, 484-492, 2019) (J. Fukai, J. Jpn. Colour Mater., 94, 4, 112-116, 2021). The flow of the uneven evaporation rate distribution is caused by the difference in the evaporation rate distribution between the contact line part of the droplet surface and the top of the droplet head. For example, in the droplets dripping onto the substrate, when the contact angle is less than 90°, the evaporation rate increases in the contact line part, so that the fluid moves from the top of the droplet head to the contact line part. When the contact angle is below 90°, the evaporation rate distribution is opposite, so fluid movement occurs from the contact line portion to the top of the droplet head. The flow from the change in contact angle is caused by the change in the evaporation rate of the contact line portion of the droplet surface over time. As mentioned above, there is a correlation between the contact angle and the evaporation rate, so for example, when the contact angle becomes smaller over time, fluid movement occurs from the top of the droplet head to the contact line portion. The flow from the surface tension distribution is caused by the fluid being pulled by the part with small surface tension to the part with large surface tension. When the surface tension of the contact line portion is higher than that of the top of the head, fluid movement occurs from the top of the droplet head to the contact line portion. For such a flow, the internal fluid based on the viscous force also begins to move, thereby generating a circulating flow. This is called Marangoni convection. Marangoni convection plays an important role in controlling the shape of the membrane. For example, if a surfactant is added or a functional ink with a combination of two or more solvents is used, the surface tension of the droplet is changed to control the Marangoni convection, and the membrane shape can be manipulated to a certain extent.

[0121] For example, by using γ, which is a ratio of viscosity η (mP·s) to surface tension σ (mN / m) expressed by the following formula described in Japanese Patent No. 5934961, the degree of convex shape and concave shape can be predicted. γ=σ / η

[0122] When a 60 nm functional layer is temporarily formed using a solvent having a γ greater than 1.9, it tends to have a concave shape, and when a 60 nm functional layer is temporarily formed using a solvent having a γ less than 1.9, it tends to have a convex shape. Therefore, from the viewpoint of the shape of the functional layer, the γ of the solvent used in the functional ink for producing the functional layer 1 is preferably smaller than the γ of the solvent used in the functional ink for producing the functional layer 2 .

[0123] <Temporary production of functional layers> In the organic electroluminescent element or organic EL display panel of the present invention, and in the organic electroluminescent element or organic EL display panel in the design method of the present invention, in order to select the functional layer 1 and functional layer 2 contained in the functional film of the organic electroluminescent element, it is preferable to temporarily produce a film formed only of the ink for functional layer 1 and a film formed only of the ink for functional layer 2 to confirm the shape of each film. Here, the so-called temporary production means that, for the divided regions contained in the organic electroluminescent element or organic EL display panel, a film formed only of the ink for functional layer 1, a film formed only of the ink for functional layer 2, and / or a film in which the film formed only of the ink for functional layer 1 and the film formed only of the ink for functional layer 2 are laminated are produced to confirm the shape of the film.

[0124]

[0124] The functional ink used for temporarily producing the film formed only of the ink for functional layer 1 uses the same amount of the same ingredients as the functional ink for functional layer 1 in the actual production of the functional film. Similarly, the functional ink used for temporarily producing the film formed only of the ink for functional layer 2 uses the same amount of the same ingredients as the functional ink for functional layer 2 in the actual production of the functional film.

[0125]

[0125] The temporarily produced film can be used only for confirming the shape of the film. In addition, a film can be further laminated on the temporarily produced film to produce the functional film used in the organic electroluminescent element or organic EL display panel.

[0126]

[0126] Furthermore, instead of using the divided regions contained in the organic electroluminescent element or organic EL display panel for the temporary production of the functional layer, the temporary production of the functional layer can be carried out using the separately produced divided regions for temporary production by the same method. When separately producing the divided regions for temporary production, the dropping amount of the functional ink per one divided region and the conditions of the size of the divided regions used in the evaluation are set to be the same as those for the production of the divided regions contained in the organic electroluminescent element or organic EL display panel. However, the conditions of the number of divided regions of the substrate for temporary production, the area coated with the functional ink, the number of ink drops per divided region, and the size of adjacent divided regions do not necessarily have to be the same.

[0127] <Layers other than the functional layers contained in the functional film> In the present invention, in addition to the functional layer 1 and functional layer 2, the functional film may further include layers. As such layers, for example, a functional layer that is flat when formed as a single layer and is neither convex nor concave, a functional layer formed by vapor deposition, etc. can be cited.

[0128] <Solvent> Hereinafter, organic solvents that can be used in the present invention will be described by way of example. It should be noted that in this specification, organic solvents are sometimes simply referred to as "solvents" or "solvents".

[0129] (Types of organic solvents) There is no particular limitation on the organic solvents that can be used in the present invention. However, in order to effectively dissolve functional materials, aromatic organic solvents, linear aliphatic organic solvents, and cyclic aliphatic organic solvents are preferred, and aromatic organic solvents and cyclic aliphatic organic solvents are more preferred, and aromatic organic solvents are further preferred.

[0130] There is no particular limitation on the aromatic organic solvents that can be used in the present invention. Preferred examples include water-insoluble aromatic solvents such as aromatic hydrocarbon solvents, aromatic ester solvents, aromatic ether solvents, and aromatic ketone solvents.

[0131] As the aromatic hydrocarbon solvent, benzene derivatives, naphthalene derivatives, tetrahydronaphthalene derivatives, biphenyl derivatives, and diphenylmethane derivatives are preferred.

[0132] There is no particular limitation on the benzene derivative. Preferred are alkylbenzene derivatives in which the total number of carbon atoms of the substituents is 2 or more and 12 or less and the substituents have a linear, branched, or cyclic alkyl group. Examples include n-ethylbenzene, 1,3,5-trimethylbenzene, n-propylbenzene, isopropylbenzene, 1,3-diisopropylbenzene, 1,3,5-triisopropylbenzene, n-butylbenzene, sec-butylbenzene, tert-butylbenzene, n-pentylbenzene, n-hexylbenzene, n-heptylbenzene, n-octylbenzene, n-nonylbenzene, n-decylbenzene, dodecylbenzene, cyclohexylbenzene, etc.

[0133] There is no particular limitation on the naphthalene derivative. Preferred are alkylnaphthalene derivatives in which the total number of carbon atoms of the substituents is 2 or more and 6 or less and the substituents have a linear, branched, or cyclic alkyl group. Examples include 1-methylnaphthalene, 2-methylnaphthalene, 1-ethylnaphthalene, 2-ethylnaphthalene, 2-isopropylnaphthalene, 2,6-dimethylnaphthalene, 2,7-diisopropylnaphthalene, 1-butylnaphthalene, 2-cyclohexylnaphthalene, 1-phenylnaphthalene, etc.

[0134] There is no particular limitation on the tetrahydronaphthalene derivative. Examples include tetrahydronaphthalene, 1,2-dihydronaphthalene, 1,4-dihydronaphthalene, etc., which may also be substituted with an alkyl group having 1 to 6 carbon atoms.

[0135] There is no particular limitation on the biphenyl derivative. Preferred are biphenyl derivatives substituted with an alkyl group having 1 to 6 carbon atoms. Examples include 3-ethylbiphenyl, 4-isopropylbiphenyl, 4-butylbiphenyl, etc.

[0136] As the diphenylmethane derivative, there is no particular limitation, and preferably it is a diphenylmethane derivative substituted with an alkyl group having 1 to 6 carbon atoms. For example, 1,1-diphenylethane, 1,1-diphenylpentane, 1,1-diphenylhexane, 1,1-bis(3,4-dimethylphenyl)ethane, benzyltoluene, etc. can be cited.

[0137] As the aromatic ester-based solvent, benzoate-based solvents, phenylacetate-based solvents, and phthalate-based solvents can be cited.

[0138] The benzoate-based solvent is a compound having a benzoic acid and an ester bond, and a compound formed by bonding a benzoic acid which may have a substituent to an alcohol having 1 or more and 12 or less carbon atoms through an ester bond can be used. Although there is no particular limitation, the substituent that can be had is preferably a linear, branched or cyclic alkyl group having 1 or more and 12 or less carbon atoms, a linear, branched or cyclic alkoxy group having 1 or more and 12 or less carbon atoms, or an aromatic-based substituent having 6 or more and 12 or less carbon atoms. These substituents can be plural, and in the case of being plural, the total number of carbon atoms as the substituent is preferably 2 or more and 12 or less. As the benzoate-based solvent, for example, ethyl benzoate, n-butyl benzoate, n-pentyl benzoate, isopentyl benzoate, n-hexyl benzoate, 2-ethylhexyl benzoate, benzyl benzoate, methyl 4-methylbenzoate, methyl 3-methylbenzoate, methyl 2-methylbenzoate, ethyl 4-methylbenzoate, ethyl 3-methylbenzoate, ethyl 2-methylbenzoate, ethyl 4-methoxybenzoate, etc. can be cited.

[0139] As the phenylacetate-based solvent, there is no particular limitation, and ethyl phenylacetate etc. can be cited.

[0140] As the phthalate-based solvent, there is no particular limitation, and dimethyl phthalate, diethyl phthalate, dibutyl phthalate can be cited.

[0141] As other preferred aromatic ester-based solvents, 2-phenoxyethyl acetate, 2-phenoxyethyl isobutyrate, etc. can be cited.

[0142] The aromatic ether-based solvent is a compound having an aromatic ring and an ether bond, and there is no particular limitation, and the following compounds can be cited. As a benzene derivative having a linear, branched or cyclic alkyl group having 1 or more and 12 or less carbon atoms and 1 ether bond, for example, anisole, 4-methylanisole, butyl phenyl ether, hexyl phenyl ether, diphenyl ether, benzyl phenyl ether, dibenzyl ether; As a diphenyl ether derivative substituted with a linear or branched alkyl group having 1 or more and 6 or less carbon atoms, for example, 2-phenoxytoluene, 3-phenoxytoluene, 4-phenoxytoluene; As a benzene derivative having a linear or branched alkyl group with 1 to 6 carbon atoms and two ether bonds, such as 1,4 - diethoxybenzene, 1 - ethoxy - 4 - hexyloxybenzene; As other aromatic ether - based solvents, 2 - phenoxyethanol, phenoxyethoxyethanol:

[0143] Aromatic ketone - based solvents are compounds having an aromatic ring and a ketone structure, and examples thereof include: 1 - acetylnaphthalene, acetophenone, 4’ - ethylacetophenone, etc.

[0144] It should be noted that in order to control the surface tension, a surface modifier may be contained in the solvent. By adding a small amount of the surface modifier to the liquid, functionality can be imparted to the liquid surface or the solid surface obtained by coating the liquid. As the functions to be imparted here, examples include: liquid repellency, non - adhesiveness, wettability, smoothness, dispersibility, defoaming property, etc.

[0145] As a material that can be used as a surface modifier, a material that easily segregates on the liquid surface is preferred. Specifically, examples include: materials containing silicon or fluorine (polymers, oligomers, low - molecules), paraffin, or surfactants, etc. Among them, the so - called surfactant is a substance having an amphiphilic chemical structure, and the amphiphilic chemical structure includes a hydrophilic part (group) and a hydrophobic part (group), and is used for a wide range of applications such as dispersants, foaming agents, defoaming agents, emulsifiers, food additives, moisturizers, antistatic agents, wettability improvers, lubricants, rust inhibitors, etc. The hydrophilic part of such a surfactant is roughly classified into cationic, anionic, amphoteric surfactants, and non - ionic surfactants. In the present invention, a non - ionic surfactant is preferably used so as not to interfere with the energization in the organic electroluminescent element or the organic EL display panel.

[0146] (Boiling point) The organic solvent used in the present invention is not particularly limited, and an organic solvent having a boiling point of 200 °C or higher is preferred, more preferably an organic solvent having a boiling point of 230 °C or higher, further preferably an organic solvent having a boiling point of 250 °C or higher, and most preferably an organic solvent having a boiling point of 270 °C or higher. In addition, a boiling point of 350 °C or lower is preferred, more preferably a boiling point of 340 °C or lower, and further preferably a boiling point of 330 °C or lower.

[0147] For example, since the ink filled in the inkjet head dries starting from the front end of the nozzle, the solid content concentration tends to increase at the front end of the nozzle. If this state is maintained, the solid content will precipitate at the front end of the nozzle, resulting in clogging of the nozzle and potentially causing fatal damage to the inkjet device. To avoid problems caused by nozzle clogging, an organic solvent with a boiling point of 200 °C or higher is preferred, an organic solvent with a boiling point of 230 °C or higher is more preferred, an organic solvent with a boiling point of 250 °C or higher is further preferred, and an organic solvent with a boiling point of 270 °C or higher is most preferred.

[0148] On the other hand, in the manufacturing process of an organic electroluminescent element or an organic EL display panel, there is a step of obtaining a functional film by volatilizing an organic solvent. Therefore, an organic solvent within a boiling point range that can be dried using a vacuum drying device is preferably used. From this perspective, the boiling point of the first solvent is preferably 350 °C or lower, more preferably 340 °C or lower, and further preferably 330 °C or lower.

[0149] (Vapor pressure) Vapor pressure refers to the pressure of the gas phase when the liquid phase and gas phase of the solvent reach a layered equilibrium state. The boiling point of the solvent is the temperature at which the partial pressure of the vapor pressure of the solvent is equal to the vapor pressure. Vapor pressure can be determined by experimental methods such as the static method, boiling point method, liquid vapor pressure gauge (isoteniscope), and gas flow method. However, the vapor pressure in the present invention refers to the vapor pressure calculated using Advanced Chemistry Development (ACD / Labs) software V11.02 (Copyright 1994 - 2021 ACD / Labs) at 25 °C.

[0150] (Type and amount of organic solvent contained) The organic solvent used in the present invention can be a single solvent of one type or a mixed solvent of two or more types for each functional ink.

[0151] In the case of using a mixed solvent of two or more types, as described above, in order to balance drying inhibition at the front end of the nozzle of the inkjet head and ease of drying during film formation, two organic solvents with different boiling points can also be used. To prevent drying and clogging of the nozzle at the front end of the inkjet head, an organic solvent with a boiling point of 270 °C or higher is preferably included. In addition, the organic solvent with a boiling point of 270 °C or higher can be one type or two or more types. To prevent drying and clogging of the ink at the front end of the nozzle, the organic solvent with a boiling point of 270 °C or higher is preferably contained at 10% by weight or more, more preferably 15% by weight or more, and further preferably 25% by weight or more based on the total composition.

[0152] On the other hand, since a solvent with a high boiling point can suppress drying at the nozzle tip, in order to ensure the drying property of the ink, the remaining solvent may contain an organic solvent with a low boiling point. Regarding the organic solvent with a low boiling point, the boiling point is preferably 265°C or lower, more preferably 250°C or lower. The organic solvent with a low boiling point may be one kind or two or more kinds. For the purpose of contributing to the drying property of the composition, it is preferably contained in an amount of 30% by weight or more, more preferably 40% by weight or more, and further preferably 50% by weight or more based on the total composition.

[0153] In the present invention, since the organic solvent is volatilized by a method such as vacuum drying to obtain a functional film, the organic solvents are generally volatilized in the order of increasing boiling point. There is a tendency that the organic solvent remaining until the end during the volatilization process has a great influence on the shape of the functional film. That is, among the organic solvents contained in the functional ink for forming the functional layer 1 and all the organic solvents contained in the functional ink for forming the functional layer 2, there is a tendency that the solvent with the highest boiling point has a great influence on the shape of the functional film.

[0154] On the other hand, when the boiling point of the aforementioned organic solvent with the highest boiling point is relatively close to the boiling points of the other organic solvents, it causes the co-boiling of each organic solvent during the drying process, and it may not be possible to fully exert the function of the aforementioned organic solvent with the highest boiling point. To prevent this, the difference between the boiling point of the aforementioned organic solvent with the highest boiling point and the boiling point of the organic solvent with the lowest boiling point among all the organic solvents contained in the functional ink is preferably 20°C or more.

[0155] The content of the aforementioned organic solvent with the highest boiling point is preferably 5% by weight or more, more preferably 10% by weight or more, further preferably 15% by weight or more, and most preferably 20% by weight or more based on all the organic solvents contained in the functional ink.

[0156] The content of the aforementioned organic solvent with the highest boiling point is preferably less than 90% by weight, more preferably less than 80% by weight, further preferably less than 70% by weight, and most preferably less than 50% by weight based on all the organic solvents contained in the functional ink. Further, it is preferably 5% by weight or more and less than 90% by weight, more preferably 10% by weight or more and less than 80% by weight, further preferably 15% by weight or more and less than 70% by weight, and most preferably 20% by weight or more and less than 50% by weight. By being within the above range, it has the function of sufficiently determining only the flatness of the film, and other solvents can be appropriately contained considering solubility and the like.

[0157] It should be noted that the boiling point of the solvent in this specification is the value measured under atmospheric pressure.

[0158] (Combination of organic solvents) Although not particularly limited, as a combination of an organic solvent with a high boiling point and an organic solvent with a low boiling point, it is preferably any one of benzene which may have a substituent, naphthalene which may have a substituent, diphenylmethane which may have a substituent, biphenyl which may have a substituent, benzoate, aromatic ether, and aromatic ketone.

[0159] Preferably, examples of the organic solvent with a high boiling point include: octylbenzene, nonylbenzene, decylbenzene, dodecylbenzene, hexyl benzoate, 2-ethylhexyl benzoate, benzyl benzoate, acetylnaphthalene, methyl naphthoacetate, ethyl naphthoacetate, isopropylnaphthalene, diisopropylnaphthalene, butylnaphthalene, pentylnaphthalene, methoxynaphthalene, dimethyl phthalate, diethyl phthalate, ethylbiphenyl, isopropylbiphenyl, diisopropylbiphenyl, triisopropylbiphenyl, butylbiphenyl, 1,1-diphenylethane, 1,1-diphenylpropane, 1,1-diphenylbutane, 1,1-diphenylpentane, 1,1-diphenylhexane, 2-phenoxyethyl isobutyrate, and one or more of these.

[0160] In addition, preferred examples of the organic solvent with a low boiling point include: methylnaphthalene, ethylnaphthalene, isopropylnaphthalene, ethyl benzoate, propyl benzoate, butyl benzoate, isobutyl benzoate, pentyl benzoate, isopentyl benzoate, methyl methylbenzoate, ethyl methylbenzoate, and one or more of these.

[0161] <Viscosity> In consideration of, for example, a coating method of filling an inkjet head and ejecting, the viscosity of the functional ink of the present invention is preferably 1 mPa·s or more and 20 mPa·s or less at 23°C. An inkjet head that usually uses a piezoelectric element extrudes the composition filled in the ink chamber of the head by the deformation pressure of the piezoelectric element. Therefore, when forming a composition with a viscosity greater than 20 mPa·s, the pressure of the piezoelectric element will be insufficient, resulting in failure to eject. On the other hand, from the viewpoint of forming a composition that can easily hold the ink in the head without dripping from the nozzle, the viscosity of the composition is preferably 1 mPa·s or more.

[0162] In the present invention, the viscosity of the organic solvent can be measured using an E-type viscometer RE85L (manufactured by Toki Sangyo Co., Ltd.) at 23°C with a cone-plate rotation speed of 20 rpm to 100 rpm.

[0163] <Surface tension> The surface tension of the functional ink of the present invention is preferably 25 mN / m or more, and in addition, preferably 45 mN / m or less. It is considered that by making the surface tension of the functional ink within this range, stable ejection or stable film formation can be achieved using an inkjet device. In the case of a functional ink with a low surface tension, it will significantly wet and spread onto the nozzle plate of the inkjet head, resulting in unstable ejection or flight deviation. In addition, in the case of a low surface tension, the ejected composition will have an improper liquid-cutting position and is prone to elongation, and is also likely to be the main cause of satellite droplets, etc. On the other hand, when the surface tension is too high, convection caused by Laplace pressure is likely to occur during drying after coating on the pixel portion of the substrate, resulting in an unstable film shape.

[0164] The surface tension of the organic solvent or functional ink in the present invention can be measured at 23.0 °C by the plate lifting method using a platinum plate or the sessile drop method using a contact angle meter DMο-501 (manufactured by Kyowa Interface Science Co., Ltd.).

[0165] [Other components] In the present invention, the functional ink may contain components other than the functional material and the organic solvent. For example, it may also contain antioxidants, additives that change the physical properties of the functional ink, etc. These components are important factors determining the storage stability of the functional ink, the ejection stability from the inkjet head, etc., but are not preferred as they have a great impact on the inherent performance of the functional ink. Therefore, relative to the total amount of the functional ink, it is preferably 1 wt% or less, more preferably 0.1 wt% or less, and further preferably 0.05 wt% or less.

[0166] [Functional material] The functional material refers to a material having functions such as charge transport and charge injection or a material that enhances these functions. For charge transport, hole transportability is preferred, and for charge injection, hole injectability is preferred. A material having an enhanced charge transport function refers to a material that enhances the charge transport function of other materials having charge transportability. A material having an enhanced charge injection function refers to a material that enhances the charge injection function of other materials having charge injectability. For example, by doping an electron-accepting material into a hole transport material, the electron-accepting material oxidizes the hole transport material to generate a cation radical, thereby enhancing the hole transportability and / or hole injectability of the hole transport material. In this case, the electron-accepting material is a material that enhances the hole transportability and / or hole injectability of the hole transport material.

[0167] In addition, as the functional material in the present invention, it is preferably possible to use the materials for the hole injection layer or the hole transport layer described later, and particularly preferably the material for the hole injection layer. Hereinafter, specific examples will be shown to explain the details of the functional materials that can be used in the present invention. However, the scope of the present invention is not limited to the functional materials described below.

[0168] <Molecular weight of charge transport compound> The charge transport compound in the present invention can be a high molecular weight compound or a low molecular weight compound, and a high molecular weight compound is preferred.

[0169] Regarding charge transport high molecular weight compounds, they usually have a large charge transport ability in the main chain direction of the high molecular weight compound. Therefore, the larger the average molecular weight, the more stable the charge transport can be achieved. In order to ensure the function of transporting charges, the weight average molecular weight is usually 10,000 or more, preferably 12,000 or more, more preferably 15,000 or more. On the other hand, high molecular weight compounds with a large weight average molecular weight have the characteristic that the viscosity becomes higher when made into ink. In order to keep it within the above-mentioned preferred viscosity range, it is preferred that the weight average molecular weight becomes smaller to a certain extent. Specifically, the weight average molecular weight of the high molecular weight compound is usually 1,000,000 or less, preferably 500,000 or less, more preferably 100,000 or less, further preferably 70,000 or less, and particularly preferably 50,000 or less.

[0170] Regarding charge transport low molecular weight compounds, the molecular weight is usually 5,000 or less, preferably 4,000 or less, more preferably 3,000 or less, further preferably 2,500 or less, and particularly preferably 2,000 or less. On the other hand, when forming a film as a general functional film, it is baked at a certain temperature to remove the residual solvent to form a functional film without impurities, so as to fully function as an organic electroluminescent element or an organic EL display panel. At this time, when the material has low heat resistance, phenomena such as film shrinkage or film peeling may occur, resulting in an uneven film. From the viewpoint of ensuring film heat resistance, the molecular weight of the charge transport low molecular weight compound is preferably 500 or more, more preferably 650 or more, and further preferably 800 or more.

[0171] In addition, in order to improve the charge transport performance, the functional ink of the present invention preferably contains an electron accepting compound. Further, as a functional material, the functional ink of the present invention preferably contains at least one hole transport compound and at least one electron accepting compound.

[0172] It should be noted that the weight-average molecular weight and number-average molecular weight of the charge-transporting polymer compound in the present invention are determined by SEC (size exclusion chromatography). In SEC measurement, the higher the molecular weight component, the shorter the elution time, and the lower the molecular weight component, the longer the elution time. By using a calibration curve calculated from the elution time of polystyrene (standard sample) with known molecular weight, the elution time of the sample is converted into molecular weight, and the weight-average molecular weight and number-average molecular weight are calculated.

[0173] <Crosslinking group> In the present invention, in order not to dissolve the charge-transporting low molecular compound in the solvent of the composition further coated on the upper layer of the functional film, it is preferred that the charge-transporting low molecular compound has a crosslinking group. In this case, in order to avoid dissolution only by chain crosslinking of the charge-transporting material, the number of crosslinking groups contained in one molecule of the charge-transporting low molecular compound is preferably 2 or more. In addition, the same applies to the charge-transporting polymer compound, and the number of crosslinking groups contained in one repeating unit is preferably 2 or more. Further, in order to more reliably suppress the elution of the charge-transporting polymer compound, it is preferred that there are 2 or more crosslinking groups per 10,000 molecular weights.

[0174] The crosslinking group is preferably a substituent that undergoes a chemical reaction by an external force such as light or heat. Preferred examples of the crosslinking group are heat-crosslinking groups that undergo a crosslinking reaction by heat, but are not limited to the following. For example, groups derived from benzocyclobutene ring, naphthocyclobutene ring or oxetane ring, vinyl group, acrylic group, styryl group, etc. can be cited. It should be noted that any crosslinking group may have a substituent, and preferred ones are methyl group, methoxy group, etc. As described above, the functional ink of the present invention preferably contains a functional material having a crosslinking group. More preferably, all the functional materials contained in the functional ink of the present invention have a crosslinking group.

[0175] [Content of organic solvent and functional material] The content of the functional material in the functional ink of the present invention is not particularly limited, but in order to form a preferred film thickness of the functional film on the organic electroluminescent element or the organic EL display panel, it is preferably 0.1% by weight or more, more preferably 0.5% by weight or more, and further preferably 1.0% by weight or more. In addition, from the viewpoint of suppressing precipitation in the functional ink, it is preferably 20% by weight or less, more preferably 15% by weight or less, and further preferably 10% by weight or less. Therefore, the content of the organic solvent in the functional ink of the present invention is preferably 99.9% by weight or less, more preferably 99.5% by weight or less, further preferably 99.0% by weight or less, preferably 80% by weight or more, more preferably 85% by weight or more, and further preferably 90% by weight or more.

[0176] In the present invention, the charge-transporting low molecular weight compound is a material for making the film thickness uniformity of the functional film in the region partitioned by the dam good. It is preferably 10% by weight or more, more preferably 15% by weight or more, and still more preferably 20% by weight or more with respect to all the functional materials. On the other hand, when the content rate of the charge-transporting low molecular weight compound increases, there are problems from the viewpoint of heat resistance as described above. It is preferably 75% by weight or less, more preferably 60% by weight or less, and still more preferably 50% by weight or less with respect to all the functional materials.

[0177] In addition, in the present invention, the charge-transporting high molecular weight compound is a material mainly for charge transport. It is preferably 20% by weight or more, more preferably 25% by weight or more, and still more preferably 30% by weight or more with respect to all the functional materials. On the other hand, when the content rate of the charge-transporting high molecular weight compound increases, it is difficult to form a flat film due to the influence of thickening during the drying process. Therefore, it is preferably 90% by weight or less, more preferably 85% by weight or less, and still more preferably 80% by weight or less with respect to all the functional materials. In addition, considering the above situation, the content ratio of the low molecular weight compound to the high molecular weight compound in terms of weight ratio is preferably low molecular weight compound: high molecular weight compound = 1:0.3 to 3, and particularly preferably 1:1 to 2.

[0178] When the functional ink of the present invention contains an electron-accepting compound, from the viewpoint of generating carriers in the charge-transporting compound and improving conductivity, the electron-accepting compound is preferably 1% by weight or more, more preferably 3% by weight or more, and still more preferably 5% by weight or more with respect to all the functional materials. On the other hand, when the content of the electron-accepting compound containing fluorine is too high, the surface energy of the functional film decreases and it is difficult to perform layer coating. Therefore, the electron-accepting compound is preferably 50% by weight or less, more preferably 30% by weight or less, and still more preferably 20% by weight or less with respect to all the functional materials.

[0179] In addition, from the above viewpoints, the content ratio of the charge-transporting compound (preferably the total of the charge-transporting high molecular weight compound and the charge-transporting low molecular weight compound) to the electron-accepting compound in terms of weight ratio is preferably charge-transporting compound: electron-accepting compound = 1:0.01 to 1, and particularly preferably 1:0.05 to 0.2.

[0180] [Preparation of Functional Ink] The functional ink in the present invention can be prepared by mixing a functional material with an organic solvent and heating it for a certain period of time to dissolve or disperse it. To uniformly dissolve or disperse the functional material in the solvent, the heating temperature is preferably 80 °C or higher, more preferably 90 °C or higher, and further preferably 100 °C or higher, for example, 100 - 115 °C. In addition, the heating time is preferably 30 minutes or longer, more preferably 45 minutes or longer, and further preferably 60 minutes or longer, for example, 60 - 180 minutes.

[0181] The heated functional ink is filtered using a membrane filter or a depth filter, etc., to remove coarse particles before use. When considering ejecting and coating the functional ink from the nozzles of an inkjet head, the pore size of the filter is preferably 0.5 μm or less, more preferably 0.2 μm or less, and further preferably 0.1 μm or less.

[0182] [Film formation using the wet film formation method] The functional ink in the present invention is suitable for forming a functional film of an organic electroluminescent element or an organic EL display panel. The structure of the organic electroluminescent element or the organic EL display panel will be described later.

[0183] The organic electroluminescent element or the organic EL display panel in the present invention, and the organic electroluminescent element or the organic EL display panel in the design method of the present invention, usually have light-emitting pixels in a minute area, and the minute area is partitioned by a partition wall called a partition layer (dam, bank) having liquid repellency on a substrate provided with electrodes. By ejecting the functional ink of the present invention into the minute area partitioned by the partition layer, drying and appropriately heating are performed to form a functional film.

[0184] The ejection method is a method of ejecting droplets smaller than the minute area partitioned by the partition layer from minute nozzles, and it is preferably to fill the minute area partitioned by the partition layer with the functional ink of the present invention by ejecting a plurality of droplets. As the ejection method, an inkjet method is preferred.

[0185] In the wet film formation method, after filling the minute area partitioned by the dam with the functional ink, the solvent is volatilized and dried by an appropriate method to obtain a functional film. To volatilize and dry the solvent, it may include heat drying or reduced pressure drying, but is not limited to the following.

[0186] For example, reduced pressure drying means disposing a substrate coated with a composition in a closable metal or glass vacuum chamber, and reducing the pressure of the environment in the chamber using a vacuum pump or the like to volatilize the solvent. As the vacuum pump, a rotary oil pump, a mechanical booster pump, a dry scroll pump, a dry roots pump, a turbomolecular pump, a cryopump, etc. can usually be used.

[0187] Since the solvent during film formation is easily removed, the pressure during reduced-pressure drying is preferably 1×10 1 Pa or less, more preferably 1×10 0 Pa or less, and even more preferably 1×10 -1 Pa or less.

[0188] Reduced-pressure drying can be carried out while heating. In this case, since the solvent during film formation is easily removed, the temperature is preferably 10°C or higher, more preferably 15°C or higher, and even more preferably 20°C or higher. Further, from the viewpoint of preventing the solvent contained in the ink from boiling suddenly, the temperature during reduced-pressure drying is preferably 200°C or lower, more preferably 190°C or lower, and even more preferably 180°C or lower.

[0189] In order to moderately spend a long time to lower the needle position of the functional ink and avoid the organic solvent from continuously contacting the dam for too long, the time for reduced-pressure drying is preferably 1 minute or more and less than 15 minutes, more preferably 2 minutes or more and less than 12 minutes, and even more preferably 3 minutes or more and less than 10 minutes.

[0190] If it is within the preferred boiling point range of the organic solvent in the present invention, the above-mentioned pump can be used to volatilize it sufficiently. However, in order to further dry the trace residual solvent sufficiently, heating drying is sometimes carried out subsequently. Further, the charge transport polymer compound, low molecular compound of the present invention, and when present, heating is carried out to crosslink the crosslinking groups of functional materials such as electron-accepting compounds. The heating step can also serve as the heating for crosslinking while drying. From the viewpoint of saving the number of processes, it is also preferred that the heating drying serves as the heating for crosslinking, that is, drying and crosslinking are carried out by heating. The heating temperature is preferably the temperature and time at which the functional film does not crystallize or agglomerate. In this specification, such a heating step is also referred to as "baking step".

[0191] The heating temperature in the heating step is usually 80°C or higher, preferably 100°C or higher, further preferably 150°C or higher, more preferably 200°C or higher, usually 300°C or lower, preferably 270°C or lower, and further preferably 240°C or lower. The heating time is usually 1 minute or more, preferably 3 minutes or more, more preferably 5 minutes or more, usually 120 minutes or less, preferably 90 minutes or less, and more preferably 60 minutes or less.

[0192] The heating process can be carried out by means of a hot plate, an oven, infrared irradiation, etc. When heating by infrared irradiation that directly applies molecular vibration, the heating time close to the lower limit mentioned above is sufficient. When heating with a hot plate where the substrate is in direct contact with the heat source or the heat source and the substrate are arranged very close to each other, a longer time than infrared irradiation is required. In the case of oven heating, that is, when heating with the gas in the oven, usually an inert gas such as air, nitrogen, or argon, it takes time for the temperature to rise. Therefore, a heating time close to the upper limit of the heating time mentioned above is preferred. The heating time can be appropriately adjusted according to the heating method.

[0193] The conditions for the heating process to cause the crosslinking groups of the functional materials such as the charge-transporting polymer compound and the low-molecular compound of the present invention to crosslink with each other are important. Therefore, the heating temperature is preferably above the crosslinking start temperature of the crosslinking groups of the charge-transporting polymer compound, the low-molecular compound, and the electron-accepting compound when present, etc., of the present invention.

[0194] During the process of drying the functional ink of the present invention by volatilizing the solvent in the functional ink, the needle position of the functional ink on the side of the dam drops. However, when drying is too fast, there is not enough time to lower the pinning position, and thus no effect will be achieved. Therefore, the time when the pressure in the atmosphere of the vacuum chamber for vacuum drying reaches lower than the vapor pressure of the organic solvent with the lowest vapor pressure among the organic solvents contained in the functional ink of the present invention is not particularly limited, and is preferably 60 seconds or more. On the other hand, when the functional ink continuously contacts the side of the dam, there will be a problem that the material forming the dam slowly dissolves into the organic solvent of the functional ink. Therefore, when the pressure in the atmosphere of the vacuum chamber for vacuum drying reaches a pressure lower than the vapor pressure of the organic solvent with the lowest vapor pressure among the organic solvents contained in the functional ink of the present invention, the time is not particularly limited, and is preferably 1800 seconds or less.

[0195] [Functional film] The functional film formed from the functional ink of the present invention is preferably a film formed by crosslinking the crosslinking groups of the charge-transporting polymer compound and the low-molecular compound as functional materials with each other. The functional materials contained in the functional film are usually 70% by weight or more, preferably 80% by weight or more, more preferably 90% by weight or more, particularly preferably 95% by weight or more, and most preferably substantially 100% by weight, with the upper limit being 100% by weight. Substantially 100% by weight means that the functional film sometimes contains trace amounts of additives, residual solvents, and impurities. By having the content of the functional materials in the functional film within this range, the functions of the functional materials can be more effectively exhibited.

[0196] [Layer constitution and formation method of organic electroluminescent element] Refer toFigure 1 Preferred examples of embodiments of an organic electroluminescent element (hereinafter sometimes referred to as "the organic electroluminescent element of the present invention"; similarly, an organic EL display panel having a plurality of organic electroluminescent elements manufactured by the design method of the film thickness structure of the present invention is sometimes referred to as "the organic EL display panel of the present invention" below) manufactured using the functional ink of the present invention and the layer constitution and formation method of the organic electroluminescent element manufactured by the design method of the film thickness structure of the present invention will be described.

[0197] Figure 1 It is a cross-sectional schematic view showing a structural example of the organic electroluminescent element 110 of the present invention. Figure 1 In it, 101 represents a substrate, 102 represents an anode, 103 represents a hole injection layer, 104 represents a hole transport layer, 105 represents a light-emitting layer, 106 represents a hole blocking layer, 107 represents an electron transport layer, 108 represents an electron injection layer, and 109 represents a cathode.

[0198] The organic electroluminescent element of the present invention has an anode, a light-emitting layer, and a cathode as essential constituent layers. As needed, as Figure 1 shown, other functional layers may be provided between the anode 102 and the light-emitting layer 105 and between the cathode 109 and the light-emitting layer 105.

[0199] [Substrate] The substrate 101 is a support for the organic electroluminescent element. As the substrate 101, a plate of quartz or glass, a metal plate or foil, a plastic film or sheet, etc. can be used. In particular, a glass plate; a plate of a transparent synthetic resin such as polyester, polymethacrylate, polycarbonate, polysulfone, etc. is preferably used. In the case of using a synthetic resin substrate, it is preferable to pay attention to gas barrier properties. The gas barrier property of the substrate is not likely to cause deterioration of the organic electroluminescent element due to external air passing through the substrate, so a large one is preferred. Therefore, a method of providing a dense silicon oxide film or the like on at least one surface of the synthetic resin substrate to ensure gas barrier properties is also one of the preferred methods.

[0200] [Anode] The anode 102 is an electrode that functions to inject holes into the layer on the light-emitting layer 105 side. The anode 102 is usually composed of a metal such as aluminum, gold, silver, nickel, palladium, platinum, an alloy composed of these metals combined with indium, copper, tellurium, palladium, aluminum, a metal oxide such as indium and / or tin oxide, a metal halide such as copper iodide, carbon black, or a conductive polymer such as poly(3-methylthiophene), polypyrrole, polyaniline, etc.

[0201] The formation of the anode 102 is usually carried out by methods such as sputtering method, vacuum evaporation method, etc. When forming the anode 102 using metal microparticles such as silver, microparticles such as copper iodide, carbon black, conductive metal oxide microparticles, conductive polymer micropowders, etc., the anode 102 can also be formed by dispersing these microparticles, etc. in an appropriate binder resin solution and coating it on the substrate 101. In the case of a conductive polymer, a thin film can also be directly formed on the substrate 101 by electrolytic polymerization. It is also possible to coat a conductive polymer on the substrate 101 to form the anode 102 (Appl. Phys. Lett., Vol. 60, p. 2711, 1992).

[0202] The anode 102 is usually a single-layer structure, but it can also be made into a laminated structure composed of multiple materials according to expectations.

[0203] The thickness of the anode 102 can be appropriately selected according to the required transparency, etc. When transparency is required, the transmittance of visible light is usually set to 60% or more, preferably 80% or more. In this case, the thickness of the anode 102 is usually 5 nm or more, preferably 10 nm or more, usually 1000 nm or less, preferably around 500 nm or less. When it can be opaque, the thickness of the anode 102 is arbitrary. A substrate 101 having the function of the anode 102 can be used. Different conductive materials can also be laminated on the above-mentioned anode 102.

[0204] For the purpose of removing impurities attached to the anode 102 and adjusting the ionization potential to improve the hole injection property, it is preferable to perform ultraviolet (UV) / ozone treatment or oxygen plasma or argon plasma treatment on the surface of the anode 102.

[0205] [Pixel partition layer] In the present invention, there are the following steps: coating a liquid-repellent resist on a glass substrate having a conductive electrode pattern and providing openings in a plurality of minute regions by photolithography. As a method of coating the liquid-repellent resist, methods using coating devices such as a roll coater, a reverse coater, a bar coater, a spin coater (rotary coating device), a die coater, an inkjet printer, etc. on this substrate can be cited. If necessary, the solvent is removed by drying to form a liquid-repellent resist layer.

[0206] Next, in the exposure step, actinic energy rays such as ultraviolet rays and excimer lasers are irradiated on the liquid-repellent resist using a mask, and the liquid-repellent resist is locally exposed corresponding to the pattern of the pixel partition layer. As the exposure using ultraviolet irradiation, light sources that emit ultraviolet rays such as a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, and a carbon arc lamp can be used. The exposure amount varies depending on the composition of the photosensitive resin composition, and is preferably, for example, about 10 - 400 mJ / cm 2 or so. In the case of a negative-type lyophobic resist, the mask uses a mask in which light-shielding portions of 10 to 500 μm are arranged in a linear or rectangular shape, whereby a pattern having a plurality of minute region openings of 10 to 500 μm can be set. Next, in the developing step, a pattern is formed by developing a lyophobic resist that is exposed to the pattern corresponding to the pixel partition layer. The developing method is not particularly limited, and an immersion method, a spraying method, etc. can be used. Specific examples of the developer include: organic developers such as dimethylbenzylamine, monoethanolamine, diethanolamine, and triethanolamine; aqueous solutions such as sodium hydroxide, potassium hydroxide, sodium carbonate, ammonia, and quaternary ammonium salts. In addition, an antifoaming agent or a surfactant can be added to the developer.

[0207] Then, post-baking is performed on the developed lyophobic resist to heat and cure it, thereby obtaining the pixel partition layer. The post-baking is preferably performed at 150 to 250 °C for 15 to 60 minutes. The conditions of the lyophobic resist for manufacturing the pixel partition layer in the present invention are as follows: on the film after peeling off the lyophobic agent on the outermost surface of the lyophobic resist film formed by forming a film using the lyophobic resist as described above, the contact angle of at least one organic solvent contained in the functional ink is 26° or more and less than 50°.

[0208] After pattern formation, the surface of the substrate is treated with external energy in order to remove residues caused by resist coating or lithography. As the external energy, ultraviolet rays (UV) / ozone, oxygen plasma, plasma, etc. are preferred.

[0209] [Hole injection layer] The hole injection layer 103 is a layer that transports holes from the anode 102 to the light-emitting layer 105. When the hole injection layer 103 is provided, the hole injection layer 103 is usually formed on the anode 102.

[0210] The formation method of the hole injection layer 103 can be a vacuum evaporation method or a wet film formation method, and there is no particular limitation. From the viewpoint of reducing dark spots, the hole injection layer 103 is preferably formed by a wet film formation method. The film thickness of the hole injection layer 103 is usually in the range of 5 nm or more, preferably 10 nm or more, and usually 1000 nm or less, preferably 500 nm or less.

[0211] <Hole transport material> The composition for forming the hole injection layer usually contains a hole transport material and a solvent as constituent materials of the hole injection layer 103.

[0212] The hole transport material may be any hole-transporting compound that is commonly used in the hole injection layer 103 of an organic electroluminescent element. It may be a high molecular compound such as a polymer or a low molecular compound such as a monomer, and a high molecular compound is preferred. It should be noted that when the scope of application of the present invention is applied to the hole injection layer 103, the composition is a composition characterized by containing: at least one hole-transporting high molecular material having a crosslinking group with a weight average molecular weight of 10,000 or more, at least one hole-transporting low molecular material having a crosslinking group with a molecular weight of 5,000 or less, and at least one aromatic organic solvent.

[0213] As the hole transport material, from the viewpoint of the charge injection barrier from the anode 102 to the hole injection layer 103, a compound having an ionization potential of 4.5 eV to 6.0 eV is preferred. Examples of the hole transport material include: aromatic amine derivatives, phthalocyanine derivatives, porphyrin derivatives, oligothiophene derivatives, polythiophene derivatives, benzylbenzene derivatives, compounds formed by connecting a tertiary amine with a fluorene group, hydrazone derivatives, silazane derivatives, silanamine derivatives, phosphamine derivatives, quinacridone derivatives, polyaniline derivatives, polypyrrole derivatives, polyaniline derivatives, poly(phenylene vinylene) derivatives, polyquinoline derivatives, polyquinoxaline derivatives, carbon, etc.

[0214] In the present invention, the derivative, for example, if an aromatic amine derivative is taken as an example, includes the aromatic amine itself and a compound having an aromatic amine as a main skeleton, and may be a polymer or a monomer.

[0215] The hole transport material used as the material of the hole injection layer 103 may contain any one of such compounds alone, or may contain two or more. When two or more hole transport materials are contained, the combination is arbitrary, but it is preferred to use one or two or more aromatic tertiary amine high molecular compounds in combination with one or two or more other hole transport materials.

[0216] Among the above examples, as the hole transport material, from the aspects of amorphousness and visible light transmittance, an aromatic amine compound is preferred, and an aromatic tertiary amine compound is particularly preferred. The aromatic tertiary amine compound refers to a compound having an aromatic tertiary amine structure, and also includes a compound having a group derived from an aromatic tertiary amine.

[0217] The type of the aromatic tertiary amine compound is not particularly limited, but from the aspect of uniform light emission brought by the surface smoothing effect, a high molecular compound (a polymerized compound in which repeating units are connected) having a weight average molecular weight of 1,000 or more and 1,000,000 or less is further preferred. Preferred examples of the aromatic tertiary amine high molecular compound include high molecular compounds having repeating units represented by the following formula (1) or formula (11).

[0218] [Chemical Formula 1]

[0219] (In Formula (1), Ar 3 represents an aromatic hydrocarbon ring group or an aromatic heterocyclic group which may have substituents, and Ar 4 represents a divalent aromatic hydrocarbon ring group or a divalent aromatic heterocyclic group which may have substituents, or a divalent group formed by directly connecting or connecting multiple of the aromatic hydrocarbon ring group and the aromatic heterocyclic group via a linking group)

[0220] In the above Formula (1), when the aromatic hydrocarbon ring group and the aromatic heterocyclic group are formed by connecting multiple via a linking group, the linking group is a divalent linking group. For example, groups selected from -O-, -C(=O)-, and (optionally substituted) -CH2- groups are connected in any order 1 to 30, preferably 1 to 5, and more preferably 1 to 3 to form a group. Among the linking groups, in terms of excellent hole injection into the light-emitting layer, Ar in Formula (1) 4 is preferably an aromatic hydrocarbon ring group or an aromatic heterocyclic group formed by connecting multiple via a linking group represented by the following Formula (2).

[0221] [Chemical Formula 2]

[0222] (In Formula (2), y1 represents an integer from 1 to 10, R 8 and R 9 each independently represent a hydrogen atom or an alkyl group, an aromatic hydrocarbon ring group, or an aromatic heterocyclic group which may have substituents. When there are multiple R 8 's and R 9 's, they may be the same or different)

[0223] [Chemical Formula 3]

[0224] In the above Formula (11), x1, x2, x3, x4, x5, x6 each independently represent an integer of 0 or more. Among them, x3 + x4 ≥ 1. Ar 11 , Ar 12 , Ar 14 each independently represent a divalent aromatic ring group having 30 or fewer carbon atoms which may have substituents. Ar 13 represents a divalent aromatic ring group having 30 or fewer carbon atoms which may have substituents or a divalent group represented by the following Formula (12), Q 11 , Q 12Each independently represents an oxygen atom, a sulfur atom, a hydrocarbon chain having 6 or fewer carbon atoms which may have a substituent, S 1 ~S 4 Each independently represents a group represented by the following formula (13). It should be noted that the so-called aromatic ring group herein refers to an aromatic hydrocarbon ring group and an aromatic heterocyclic group.

[0225] As Ar 11 、Ar 12 、Ar 14 Examples of the aromatic ring group of Ar include a monocyclic ring, a 2- to 6-fused ring, or a group formed by linking two or more of these aromatic rings. Specific examples of the aromatic ring group of a monocyclic ring or a 2- to 6-fused ring include a divalent group derived from a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzopyrene ring, ring, a triphenylene ring, an acenaphthene ring, a fluoranthene ring, a fluorene ring, a biphenyl group, a terphenyl group, a quaterphenyl group, a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, a pyrroloimidazole ring, a pyrrolopyrazole ring, a pyrrolopyrrole ring, a thiophenopyrrole ring, a thiophenothiophene ring, a furanopyrrole ring, a furanofuran ring, a thiophenofuran ring, a benzoisoxazole ring, a benzoisothiazole ring, a benzimidazole ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinoxaline ring, a phenanthridine ring, a benzimidazole ring, a peridine ring, a quinazoline ring, a quinazolinone ring, or an azulene ring. Among them, from the aspects of efficiently delocalizing negative charges and excellent stability and heat resistance, a divalent group derived from a benzene ring, a naphthalene ring, a fluorene ring, a pyridine ring, or a carbazole ring or a biphenyl group is preferred. 13 Examples of the aromatic ring group of Ar 11 、Ar 12 、Ar 14 are the same as those of Ar

[0226] [Chemical formula 4]

[0227] In the above formula (12), R 11 represents an alkyl group, an aromatic ring group, or a trivalent group composed of an alkyl group and an aromatic ring group having 40 or fewer carbon atoms, and these may have a substituent. R 12 represents an alkyl group, an aromatic ring group, or a divalent group composed of an alkyl group and an aromatic ring group having 40 or fewer carbon atoms, and these may have a substituent. Ar 31 represents a monovalent aromatic ring group or a monovalent crosslinking group, and these groups may have a substituent. x7 represents 1 to 4. When x7 is 2 or more, multiple R 12 may be the same or different, and multiple Ar 31May be the same or different. The asterisk (*) represents the bonding site to the nitrogen atom of formula (11).

[0228] As R 11 The aromatic ring group is preferably a monocyclic or polycyclic aromatic ring group having 3 or more and 30 or less carbon atoms, or a group formed by connecting 2 to 6 of them. As specific examples, trivalent groups derived from a benzene ring, a fluorene ring, a naphthalene ring, a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, and groups formed by connecting 2 to 6 of these can be cited. As R 11 The alkyl group is preferably a straight-chain, branched-chain or cyclic alkyl group having 1 or more and 12 or less carbon atoms. As specific examples, groups derived from methane, ethane, propane, isopropane, butane, isobutane, pentane, hexane, octane, etc. can be cited. As R 11 The group composed of an alkyl group and an aromatic ring group having 40 or less carbon atoms is preferably a group formed by connecting a straight-chain, branched-chain or cyclic alkyl group having 1 or more and 12 or less carbon atoms and a monocyclic or polycyclic aromatic ring group having 3 or more and 30 or less carbon atoms, or a group formed by connecting 2 to 6 of them.

[0229] As R 12 Specific examples of the aromatic ring group as R include divalent groups of a benzene ring, a fluorene ring, a naphthalene ring, a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, and a connecting ring having 30 or less carbon atoms formed by connecting these. As R 12 Specific examples of the alkyl group as R include divalent groups derived from methane, ethane, propane, isopropane, butane, isobutane, pentane, hexane, octane, etc.

[0230] As Ar 31 Specific examples of the aromatic ring group as Ar include monovalent groups of a benzene ring, a fluorene ring, a naphthalene ring, a carbazole ring, a dibenzofuran ring, a dibenzothiophene ring, and a connecting ring having 30 or less carbon atoms formed by connecting these.

[0231] As an example of the preferred structure of formula (12), the following structures can be cited. In the following structures, the benzene ring or fluorene ring in the main chain of the partial structure as R may further have substituents. 11 The benzene ring or fluorene ring in the main chain of the following structures of the partial structure as R may further have substituents.

[0232] [Chemical Formula 5]

[0233] As Ar 31 Examples of the crosslinking group as Ar include groups derived from a benzocyclobutene ring, a naphthocyclobutene ring or an oxetane ring, vinyl, acrylic group, etc. From the viewpoint of the stability of the compound, a group derived from a benzocyclobutene ring or a naphthocyclobutene ring is preferred.

[0234] [Chemical Formula 6]

[0235] In the above formula (13), x and y represent integers of 0 or more. Ar 21 , Ar 23 each independently represents a divalent aromatic ring group, and these groups may have substituents. Ar 22 represents a monovalent aromatic ring group which may have substituents, R 13 represents an alkyl group, an aromatic ring group, or a divalent group composed of an alkyl group and an aromatic ring group, and these may have substituents. Ar 32 represents a monovalent aromatic ring group or a monovalent crosslinking group, and these groups may have substituents. The asterisk (*) represents the bonding site to the nitrogen atom of formula (11).

[0236] As examples of the aromatic ring group of Ar 21 , Ar 23 , they are the same as those of Ar 11 , Ar 12 , Ar 14 when.

[0237] As examples of the aromatic ring group of Ar 22 , Ar 32 , there may be mentioned: a monocyclic ring, a 2- to 6-fused ring, or a group formed by linking two or more of these aromatic rings. As specific examples, there may be mentioned monovalent groups derived from a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a perylene ring, a tetracene ring, a pyrene ring, a benzopyrene ring, ring, a triphenylene ring, an acenaphthene ring, a fluoranthene ring, a fluorene ring, a biphenyl group, a terphenyl group, a quaterphenyl group, a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, an oxadiazole ring, an indole ring, a carbazole ring, a pyrroloimidazole ring, a pyrrolopyrazole ring, a pyrrolopyrrole ring, a thiophenopyrrole ring, a thiophenothiophene ring, a furanopyrrole ring, a furanofuran ring, a thiophenofuran ring, a benzisoxazole ring, a benzisothiazole ring, a benzimidazole ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, a triazine ring, a quinoline ring, an isoquinoline ring, a cinnoline ring, a quinoxaline ring, a phenanthridine ring, a benzimidazole ring, a peridine ring, a quinazoline ring, a quinazolinone ring, or an azulene ring. Among them, from the aspects of efficiently delocalizing negative charges and excellent stability and heat resistance, a monovalent group derived from a benzene ring, a naphthalene ring, a fluorene ring, a pyridine ring, or a carbazole ring or a biphenyl group is preferred.

[0238] As examples of the alkyl group or aromatic ring group of R 13 , they are the same as those of R 12 when.

[0239] Ar 32The crosslinking group is not particularly limited. As preferred examples, groups derived from a benzocyclobutene ring, a naphthocyclobutene ring, or an oxetane ring, vinyl, acrylic group, etc. can be cited.

[0240] The above-mentioned Ar 11 ~Ar 14 、R 11 ~R 13 、Ar 21 ~Ar 23 、Ar 31 ~Ar 32 、Q 11 、Q 12 Any one of them, as long as it does not violate the gist of the present invention, may further have a substituent. As the molecular weight of the substituent, it is preferably 400 or less, and more preferably 250 or less. The type of the substituent is not particularly limited. As examples, one or more selected from the following substituent group W can be cited.

[0241] [Substituent group W] alkyl groups having 1 or more, preferably 10 or less, more preferably 8 or less carbon atoms such as methyl and ethyl; alkenyl groups having 2 or more, preferably 11 or less, more preferably 5 or less carbon atoms such as vinyl; alkynyl groups having 2 or more, preferably 11 or less, more preferably 5 or less carbon atoms such as ethynyl; alkoxy groups having 1 or more, preferably 10 or less, more preferably 6 or less carbon atoms such as methoxy and ethoxy; aryloxy groups having 4 or more, preferably 5 or more, preferably 25 or less, more preferably 14 or less carbon atoms such as phenoxy, naphthyloxy, and pyridyloxy; alkoxycarbonyl groups having 2 or more, preferably 11 or less, more preferably 7 or less carbon atoms such as methoxycarbonyl and ethoxycarbonyl; dialkylamino groups having 2 or more, preferably 20 or less, more preferably 12 or less carbon atoms such as dimethylamino and diethylamino; diarylamino groups having 10 or more, preferably 12 or more, preferably 30 or less, more preferably 22 or less carbon atoms such as diphenylamino, xylylamino, and N-carbazolyl; aralkylamino groups having 6 or more, more preferably 7 or more, preferably 25 or less, more preferably 17 or less carbon atoms such as benzylamino; acyl groups having 2 or more, preferably 10 or less, more preferably 7 or less carbon atoms such as acetyl and benzoyl; halogen atoms such as fluorine atom and chlorine atom; haloalkyl groups having 1 or more, preferably 8 or less, more preferably 4 or less carbon atoms such as trifluoromethyl; alkylthio groups having 1 or more, preferably 10 or less, more preferably 6 or less carbon atoms such as methylthio and ethylthio; arylthio groups having 4 or more, preferably 5 or more, preferably 25 or less, more preferably 14 or less carbon atoms such as phenylthio, naphthylthio, and pyridylthio; silyl groups having 2 or more, preferably 3 or more, preferably 33 or less, more preferably 26 or less carbon atoms such as trimethylsilyl and triphenylsilyl; silicon-based groups having 2 or more, preferably 3 or more, preferably 33 or less, more preferably 26 or less carbon atoms such as trimethylsilyl and triphenylsilyl; cyano group; aromatic hydrocarbon ring groups having 6 or more, preferably 30 or less, more preferably 18 or less carbon atoms such as phenyl and naphthyl; aromatic heterocyclic groups having 3 or more, preferably 4 or more, preferably 28 or less, more preferably 17 or less carbon atoms such as thiophenyl and pyridyl.

[0242] Among the above substituent groups W, from the viewpoint of improving solubility, alkyl or alkoxy groups are preferred, and from the viewpoints of charge transportability and stability, aromatic hydrocarbon ring groups or aromatic heterocyclic groups are preferred.

[0243] In particular, among polymer compounds having a repeating unit represented by formula (11), a polymer compound having a repeating unit represented by the following formula (14) is preferred because of its very high hole injection / transportability.

[0244] [Chemical Formula 7]

[0245] In the above formula (14), R 21 ~R 25 each independently represents an arbitrary substituent. Specific examples of the substituents of R 21 ~R 25 are the same as the substituents described in the aforementioned [substituent group W]. s and t each independently represent an integer of 0 or more and 5 or less. u, v, and w each independently represent an integer of 0 or more and 4 or less.

[0246] As a preferred example of the aromatic tertiary amine polymer compound, a polymer compound containing a repeating unit represented by the following formula (15) and / or formula (16) can be cited.

[0247] [Chemical formula 8]

[0248] In the above formula (15) and formula (16), Ar 45 , Ar 47 and Ar 48 each independently represent a monovalent aromatic hydrocarbon ring group which may have a substituent or a monovalent aromatic heterocyclic group which may have a substituent. Ar 44 and Ar 46 each independently represent a divalent aromatic hydrocarbon ring group which may have a substituent or a divalent aromatic heterocyclic group which may have a substituent. R 41 ~R 43 each independently represent a hydrogen atom or an arbitrary substituent.

[0249] Ar 45 , Ar 47 and Ar 48 Specific examples, preferred examples, examples of substituents that can be had, and preferred examples of substituents are the same as those of Ar 22 . Specific examples, preferred examples, examples of substituents that can be had, and preferred examples of substituents of Ar 44 and Ar 46 are the same as those of Ar 11 , Ar 12 and Ar 14 . As R 41 ~R 43 it is preferably a hydrogen atom or a substituent described in the aforementioned [substituent group W], and more preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group, an aromatic hydrocarbon ring group, or an aromatic heterocyclic group.

[0250] Hereinafter, preferred specific examples of the repeating units represented by Formula (15) and Formula (16) applicable to the present invention are listed, but the present invention is not limited to these.

[0251] [Chemical Formula 9]

[0252] <Electron-accepting compound> The composition for forming a hole injection layer preferably contains an electron-accepting compound as a constituent material of the hole injection layer 103.

[0253] An electron-accepting compound refers to a compound that preferably has oxidizing power and the ability to accept one electron from the above-mentioned hole-transporting material. Specifically, as the electron-accepting compound, a compound having an electron affinity of 4.0 eV or more is preferred, and a compound having an electron affinity of 5.0 eV or more is more preferred.

[0254] Examples of such electron-accepting compounds include: one or more compounds selected from the group consisting of triarylboron compounds, metal halides, Lewis acids, organic acids, onium salts, salts of arylamines and metal halides, salts of arylamines and Lewis acids, etc. More specifically, examples of the electron-accepting compound include: onium salts substituted with organic groups such as 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate, triphenylsulfonium tetrafluoroborate (International Publication No. 2005 / 089024, International Publication No. 2017 / 164268); high-valent inorganic compounds such as iron(III) chloride (Japanese Patent Laid-Open No. 11-251067), ammonium persulfate; cyano compounds such as tetracyanoethylene, aromatic boron compounds such as tris(pentafluorophenyl)borane (Japanese Patent Laid-Open No. 2003-31365); fullerene derivatives; iodine; sulfonic acid ions such as polystyrene sulfonic acid ion, alkylbenzene sulfonic acid ion, camphorsulfonic acid ion, etc.

[0255] The electron-accepting compound can improve the conductivity of the hole injection layer 103 by oxidizing the hole-transporting material.

[0256] <Other constituent materials> As the material of the hole injection layer 103, as long as the effects of the present invention are not significantly impaired, in addition to the above-mentioned hole-transporting material or electron-accepting compound, other components may further be contained.

[0257] <Solvent> At least one of the solvents of the composition for forming a hole injection layer used in the wet film-forming method is preferably a compound capable of dissolving the constituent materials of the hole injection layer 103.

[0258] As solvents, for example, the following can be cited: ether solvents, ester solvents, aromatic hydrocarbon solvents, amide solvents, etc.

[0259] As ether solvents, for example, the following can be cited: aliphatic ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol-1-monomethyl ether acetate (PGMEA); aromatic ethers such as 1,2-dimethoxybenzene, 1,3-dimethoxybenzene, anisole, phenetole, 2-methoxytoluene, 3-methoxytoluene, 4-methoxytoluene, 2,3-dimethylanisole, 2,4-dimethylanisole, 3-phenoxytoluene, diphenyl ether, dibenzyl ether, etc.

[0260] As ester solvents, for example, the following can be cited: aromatic esters such as phenyl acetate, phenyl propionate, methyl benzoate, ethyl benzoate, propyl benzoate, n-butyl benzoate, isobutyl benzoate, pentyl benzoate, isopentyl benzoate, methyl methylbenzoate, ethyl methylbenzoate, methyl anisate, ethyl anisate, dimethyl phthalate, diethyl phthalate, phenoxyethyl acetate, phenoxyethyl butyrate, etc.

[0261] As aromatic hydrocarbon solvents, for example, the following can be cited: toluene, xylene, cyclohexylbenzene, trimethylbenzene, tetramethylbenzene, diisopropylbenzene, triisopropylbenzene, methylnaphthalene, ethylnaphthalene, isopropylnaphthalene, diisopropylnaphthalene, ethylbiphenyl, isopropylbiphenyl, butylbiphenyl, diisopropylbiphenyl, triisopropylbiphenyl, tetralin, 1,1-diphenylethane, 1,1-diphenylpropane, 1,1-diphenylbutane, 1,1-diphenylpentane, 1,1-diphenylhexane, etc.

[0262] As amide solvents, for example, the following can be cited: N,N-dimethylformamide, N,N-dimethylacetamide, etc. In addition, dimethyl sulfoxide, etc. can also be used. Among them, aromatic esters and aromatic ethers are preferred.

[0263] These solvents can be used alone, and two or more of them can also be used in any combination and ratio.

[0264] As long as the effect of the present invention is not significantly impaired, the concentration of the hole transport material in the composition for forming the hole injection layer can be arbitrary. From the aspect of film thickness uniformity, the concentration of the hole transport material in the composition for forming the hole injection layer is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and further preferably 0.5% by weight or more. The concentration of the hole transport material in the composition for forming the hole injection layer is preferably 70% by weight or less, more preferably 60% by weight or less, and further preferably 50% by weight or less. Based on the aspect of not easily generating film thickness unevenness, this concentration is preferably small. In addition, based on the aspect of not easily generating defects in the formed hole injection layer, this concentration is preferably large.

[0265] <Formation of Hole Injection Layer by Wet Film-Forming Method> When forming the hole injection layer 103 by the wet film-forming method, usually, a material constituting the hole injection layer 103 is mixed with an appropriate solvent (solvent for hole injection layer) to prepare a composition for film formation (composition for forming hole injection layer). The composition for forming the hole injection layer 103 is coated on a layer corresponding to the lower layer of the hole injection layer (usually the anode 102) by an appropriate method, and then film formation and drying are carried out to form the hole injection layer 103.

[0266] [Hole Transport Layer] The hole transport layer 104 is a layer that transports holes from the anode 102 to the light-emitting layer 105. The hole transport layer 104 is not an essential layer in the organic electroluminescent element of the present invention. However, when the hole transport layer 104 is provided, usually, the hole transport layer 104 is formed on the hole injection layer 103 when the hole injection layer 103 is present, and is formed on the anode 102 when the hole injection layer 103 is absent.

[0267] The method for forming the hole transport layer 104 can be a vacuum evaporation method or a wet film-forming method, and there is no particular limitation. From the viewpoint of reducing dark spots, the hole transport layer 104 is preferably formed by the wet film-forming method.

[0268] As the material for forming the hole transport layer 104, a material with high hole transportability and capable of effectively transporting the injected holes is preferred. Therefore, the material for forming the hole transport layer 104 preferably has a small ionization potential, high transparency to visible light, a large hole mobility, excellent stability, and is not likely to generate impurities that will become traps during manufacturing or use. In most cases, the hole transport layer 104 is in contact with the light-emitting layer 105, so it is preferably not to quench the light emission from the light-emitting layer 105 or not to form an exciplex with the light-emitting layer 105 to cause a decrease in efficiency.

[0269] As the material for the hole transport layer 104, any material that has been conventionally used as a constituent material of the hole transport layer 104 can be used. Examples of the material for the hole transport layer 104 include: arylamine derivatives, fluorene derivatives, spiro derivatives, carbazole derivatives, pyridine derivatives, pyrazine derivatives, pyrimidine derivatives, triazine derivatives, quinoline derivatives, phenanthroline derivatives, phthalocyanine derivatives, porphyrin derivatives, silole derivatives, oligothiophene derivatives, fused polycyclic aromatic derivatives, metal complexes, etc.

[0270] Examples of the material for the hole transport layer 104 include: polyvinylcarbazole derivatives, polyarylamine derivatives, polyvinyltriphenylamine derivatives, polyfluorene derivatives, polyarylene derivatives, polyarylene ether sulfone derivatives containing tetraphenylbenzidine, polyarylene vinylidene derivatives, polysiloxane derivatives, polythiophene derivatives, poly(p-phenylene vinylene) derivatives, etc. These may be any of alternating copolymers, random polymers, block polymers, or graft polymers. In addition, it may also be a polymer having branches in the main chain and having three or more terminal portions or a so-called dendrimer.

[0271] Among them, as the material for the hole transport layer 104, polyarylamine derivatives or polyarylene derivatives are preferred. Specific examples of polyarylamine derivatives and polyarylene derivatives, etc. can be found in, for example, Japanese Patent Application Laid-Open No. 2008-98619. As the polyarylamine derivative, it is preferred to use the above-mentioned aromatic tertiary amine polymer compound.

[0272] In the case of forming the hole transport layer 104 by the wet film formation method, after preparing the composition for forming the hole transport layer in the same manner as the formation of the above-mentioned hole injection layer 103, it is dried after wet film formation. In the composition for forming the hole transport layer, in addition to the above-mentioned hole transport material, it also contains a solvent. The solvent used is the same as the solvent used in the composition for forming the hole injection layer. In addition, the film formation conditions, drying conditions, etc. are also the same as those in the formation of the hole injection layer 103. In the case where the composition for forming the hole transport layer is the composition of the present invention, the solvent is the first solvent and the second solvent of the present invention. In the case of forming the hole transport layer 104 by vacuum evaporation, the film formation conditions, etc. are also the same as those in the formation of the above-mentioned hole injection layer 103.

[0273] Considering factors such as the immersion of the low-molecular material in the light-emitting layer or the swelling of the hole transport material, the film thickness of the hole transport layer 104 is usually 5 nm or more, preferably 10 nm or more, usually 300 nm or less, and preferably 200 nm or less.

[0274] [Light-emitting layer] The light-emitting layer 105 is a layer that is excited by the recombination of holes injected from the anode 102 and electrons injected from the cathode 109 between electrodes to which an electric field is applied, and becomes the main light source. The light-emitting layer 105 is usually formed on the hole transport layer 104 when there is a hole transport layer 104, formed on the hole injection layer 103 when there is no hole transport layer 104 but there is a hole injection layer 103, and formed on the anode 102 when there is neither a hole transport layer 104 nor a hole injection layer 103.

[0275] <Material for light-emitting layer> The material for the light-emitting layer generally includes a light-emitting material and a charge-transporting material that serves as a host.

[0276] <Light-emitting material> As the light-emitting material, generally any known material that can be used as the light-emitting material of an organic electroluminescent element can be applied, without particular limitation, and a substance that emits light at a desired emission wavelength with good luminous efficiency may be used. The light-emitting material can be a fluorescent light-emitting material or a phosphorescent light-emitting material, but from the viewpoint of internal quantum efficiency, a phosphorescent light-emitting material is preferred. Further preferably, the red light-emitting material and the green light-emitting material are phosphorescent light-emitting materials, and the blue light-emitting material is a fluorescent light-emitting material.

[0277] When the composition of the present invention is a composition for forming a light-emitting layer, the following phosphorescent light-emitting materials, fluorescent light-emitting materials, and charge-transporting materials are preferably used.

[0278] <Phosphorescent light-emitting material> A phosphorescent light-emitting material refers to a material that emits light from an excited triplet state. For example, metal complex compounds having Ir, Pt, Eu, etc. are representative examples, and as the structure of the material, a metal complex is preferably included.

[0279] Among metal complexes, as phosphorescent light-emitting organometallic complexes that emit light via a triplet state, Werner-type complexes or organometallic complex compounds containing a metal selected from Groups 7 to 11 of the long-period type periodic table (hereinafter, when referred to as the "periodic table" without particular mention, it means the long-period type periodic table) as the central metal can be cited. As such phosphorescent light-emitting materials, for example, those described in International Publication No. 2014 / 024889, International Publication No. 2015 / 087961, International Publication No. 2016 / 194784, and Japanese Patent Application Laid-Open No. 2014-074000 can be cited. A compound represented by the following formula (201) or a compound represented by the following formula (205) is preferred, and a compound represented by the following formula (201) is more preferred.

[0280] [Chemical formula 10]

[0281] In formula (201), ring A1 represents an aromatic hydrocarbon ring structure that may have a substituent or an aromatic heterocyclic ring structure that may have a substituent. Ring A2 represents an aromatic heterocyclic ring structure that may have a substituent. R 101 、R 102Each is independently a structure represented by formula (202), and "*" represents a bonding site to ring A1 or ring A2. R 101 and R 102 may be the same or different. When there are multiple R 101 and R 102 respectively, they may be the same or different.

[0282] Ar 201 and Ar 203 each independently represent an aromatic hydrocarbon ring structure which may have a substituent or an aromatic heterocyclic structure which may have a substituent. Ar 202 represents an aromatic hydrocarbon ring structure which may have a substituent, an aromatic heterocyclic structure which may have a substituent, or an aliphatic hydrocarbon structure which may have a substituent. The substituents bonded to ring A1 with each other, the substituents bonded to ring A2 with each other, or the substituents bonded to ring A1 and the substituents bonded to ring A2 with each other may bond to each other to form a ring.

[0283] B 201 -L 200 -B 202 represents an anionic bidentate ligand. B 201 and B 202 each independently represent a carbon atom, an oxygen atom or a nitrogen atom, and these atoms may be atoms constituting a ring. L 200 represents a single bond or an atomic group which forms a bidentate ligand together with B 201 and B 202 . When there are multiple B 201 -L 200 -B 202 , they may be the same or different.

[0284] It should be noted that in formulas (201) and (202), i1 and i2 each independently represent an integer of 0 or more and 12 or less, i3 represents an integer of 0 or more with the upper limit being the number of substituents possible in Ar 202 , i4 represents an integer of 0 or more with the upper limit being the number of substituents possible in Ar 201 , k1 and k2 each independently represent an integer of 0 or more with the upper limit being the number of substituents possible in ring A1 and ring A2, z represents an integer of 1 to 3.

[0285] (Substituent) Unless otherwise specified, as the substituent, a group selected from the following substituent group S is preferred.

[0286] <Substituent group S> · Alkyl, preferably alkyl with 1 to 20 carbon atoms, more preferably alkyl with 1 to 12 carbon atoms, further preferably alkyl with 1 to 8 carbon atoms, and particularly preferably alkyl with 1 to 6 carbon atoms. · Alkoxy, preferably alkoxy with 1 to 20 carbon atoms, more preferably alkoxy with 1 to 12 carbon atoms, further preferably alkoxy with 1 to 6 carbon atoms. · Aryloxy, preferably aryloxy with 6 to 20 carbon atoms, more preferably aryloxy with 6 to 14 carbon atoms, further preferably aryloxy with 6 to 12 carbon atoms, and particularly preferably aryloxy with 6 carbon atoms. · Heteroaryloxy, preferably heteroaryloxy with 3 to 20 carbon atoms, more preferably heteroaryloxy with 3 to 12 carbon atoms. · Alkylamino, preferably alkylamino with 1 to 20 carbon atoms, more preferably alkylamino with 1 to 12 carbon atoms. · Arylamino, preferably arylamino with 6 to 36 carbon atoms, more preferably arylamino with 6 to 24 carbon atoms. · Aralkyl, preferably aralkyl with 7 to 40 carbon atoms, more preferably aralkyl with 7 to 18 carbon atoms, further preferably aralkyl with 7 to 12 carbon atoms. · Heteroaralkyl, preferably heteroaralkyl with 7 to 40 carbon atoms, more preferably heteroaralkyl with 7 to 18 carbon atoms. · Alkenyl, preferably alkenyl with 2 to 20 carbon atoms, more preferably alkenyl with 2 to 12 carbon atoms, further preferably alkenyl with 2 to 8 carbon atoms, and particularly preferably alkenyl with 2 to 6 carbon atoms. · Alkynyl, preferably alkynyl with 2 to 20 carbon atoms, more preferably alkynyl with 2 to 12 carbon atoms. · Aryl, preferably aryl with 6 to 30 carbon atoms, more preferably aryl with 6 to 24 carbon atoms, further preferably aryl with 6 to 18 carbon atoms, and particularly preferably aryl with 6 to 14 carbon atoms. · Heteroaryl, preferably heteroaryl with 3 to 30 carbon atoms, more preferably heteroaryl with 3 to 24 carbon atoms, further preferably heteroaryl with 3 to 18 carbon atoms, and particularly preferably heteroaryl with 3 to 14 carbon atoms. · Alkylsilyl, preferably alkylsilyl with 1 to 20 carbon atoms in the alkyl group, more preferably alkylsilyl with 1 to 12 carbon atoms in the alkyl group. · Arylsilyl, preferably arylsilyl with 6 to 20 carbon atoms in the aryl group, more preferably arylsilyl with 6 to 14 carbon atoms in the aryl group. · Alkylcarbonyl, preferably alkylcarbonyl with 2 to 20 carbon atoms. · an arylcarbonyl group, preferably an arylcarbonyl group having 7 to 20 carbon atoms.

[0287] One or more hydrogen atoms in the above groups may be substituted with fluorine atoms, or one or more hydrogen atoms may be substituted with deuterium atoms. Unless otherwise specified, an aryl group is an aromatic hydrocarbon ring and a heteroaryl group is an aromatic heterocyclic ring. · a hydrogen atom, a deuterium atom, a fluorine atom, a cyano group or -SF5.

[0288] In the above substituent group S, preferably an alkyl group, an alkoxy group, an aryloxy group, an arylamino group, an aralkyl group, an alkenyl group, an aryl group, a heteroaryl group, an alkylsilyl group, an arylsilyl group, and a group in which one or more hydrogen atoms in these groups are substituted with fluorine atoms, a fluorine atom, a cyano group or -SF5, More preferably an alkyl group, an arylamino group, an aralkyl group, an alkenyl group, an aryl group, a heteroaryl group, and a group in which one or more hydrogen atoms in these groups are substituted with fluorine atoms, a fluorine atom, a cyano group or -SF5, Still more preferably an alkyl group, an alkoxy group, an aryloxy group, an arylamino group, an aralkyl group, an alkenyl group, an aryl group, a heteroaryl group, an alkylsilyl group, an arylsilyl group, Particularly preferably an alkyl group, an arylamino group, an aralkyl group, an alkenyl group, an aryl group, a heteroaryl group, Most preferably an alkyl group, an arylamino group, an aralkyl group, an aryl group, a heteroaryl group.

[0289] In these substituent groups S, a substituent selected from the substituent groups S may further be present as a substituent. The preferred groups, more preferred groups, still more preferred groups, particularly preferred groups, and most preferred groups of the substituent that may be present are the same as the preferred groups in the substituent group S.

[0290] (Ring A1) Ring A1 represents an aromatic hydrocarbon ring structure which may have a substituent or an aromatic heterocyclic ring structure which may have a substituent.

[0291] As the aromatic hydrocarbon ring, preferably an aromatic hydrocarbon ring having 6 to 30 carbon atoms. Specifically, preferably a benzene ring, a naphthalene ring, an anthracene ring, a triphenyl ring, an acenaphthene ring, a fluoranthene ring, a fluorene ring.

[0292] As the aromatic heterocyclic ring, preferably an aromatic heterocyclic ring having 3 to 30 carbon atoms containing any one of a nitrogen atom, an oxygen atom or a sulfur atom as a heteroatom. Still more preferably a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring. As Ring A1, more preferably a benzene ring, a naphthalene ring, a fluorene ring, particularly preferably a benzene ring or a fluorene ring, and most preferably a benzene ring.

[0293] (Ring A2) Ring A2 represents an aromatic heterocyclic structure which may have substituents. As the aromatic heterocycle, an aromatic heterocycle having 3 to 30 carbon atoms containing any one of a nitrogen atom, an oxygen atom or a sulfur atom as a heteroatom is preferred. Specifically, examples include: pyridine ring, pyrimidine ring, pyrazine ring, triazine ring, imidazole ring, oxazole ring, thiazole ring, benzothiazole ring, benzoxazole ring, benzimidazole ring, quinoline ring, isoquinoline ring, quinoxaline ring, quinazoline ring, naphthyridine ring, phenanthridine ring, and preferably a pyridine ring, pyrazine ring, pyrimidine ring, imidazole ring, benzothiazole ring, benzoxazole ring, quinoline ring, isoquinoline ring, quinoxaline ring, quinazoline ring, more preferably a pyridine ring, imidazole ring, benzothiazole ring, quinoline ring, isoquinoline ring, quinoxaline ring, quinazoline ring, and most preferably a pyridine ring, imidazole ring, benzothiazole ring, quinoline ring, quinoxaline ring, quinazoline ring.

[0294] (Combination of Ring A1 and Ring A2) As a preferred combination of Ring A1 and Ring A2, when expressed as (Ring A1 - Ring A2), it is (benzene ring - pyridine ring), (benzene ring - quinoline ring), (benzene ring - quinoxaline ring), (benzene ring - quinazoline ring), (benzene ring - benzothiazole ring), (benzene ring - imidazole ring), (benzene ring - pyrrole ring), (benzene ring - diazole ring) and (benzene ring - thiophene ring).

[0295] (Substituents of Ring A1 and Ring A2) The substituents that Ring A1 and Ring A2 may have can be arbitrarily selected, but are preferably one or more substituents selected from the substituent group S.

[0296] (Ar 201 、Ar 202 、Ar 203 ) Ar 201 、Ar 203 Each independently represents an aromatic hydrocarbon ring structure which may have substituents or an aromatic heterocyclic structure which may have substituents. Ar 202 represents an aromatic hydrocarbon ring structure which may have substituents, an aromatic heterocyclic structure which may have substituents or an aliphatic hydrocarbon structure which may have substituents.

[0297] When any one of Ar 201 、Ar 202 、Ar 203 is an aromatic hydrocarbon ring structure which may have substituents, as the aromatic hydrocarbon ring structure, an aromatic hydrocarbon ring having 6 to 30 carbon atoms is preferred. Specifically, a benzene ring, naphthalene ring, anthracene ring, triphenyl ring, acenaphthene ring, fluoranthene ring, fluorene ring are preferred, more preferably a benzene ring, naphthalene ring, fluorene ring, and most preferably a benzene ring.

[0298] In Ar 201, Ar 202 When any one of them is a benzene ring which may have substituents, it is preferred that at least one benzene ring is bonded to the adjacent structure at the ortho or meta position, and more preferably at least one benzene ring is bonded to the adjacent structure at the meta position.

[0299] When Ar 201 , Ar 202 , Ar 203 is a fluorene ring which may have substituents, the 9-position and 9'-position of the fluorene ring preferably have substituents or are bonded to the adjacent structure.

[0300] When Ar 201 , Ar 202 , Ar 203 is an aromatic heterocyclic structure which may have substituents, as the aromatic heterocyclic structure, it preferably contains an aromatic heterocycle having 3 to 30 carbon atoms containing any one of a nitrogen atom, an oxygen atom or a sulfur atom as a heteroatom. Specifically, examples include: pyridine ring, pyrimidine ring, pyrazine ring, triazine ring, imidazole ring, oxazole ring, thiazole ring, benzothiazole ring, benzoxazole ring, benzimidazole ring, quinoline ring, isoquinoline ring, quinoxaline ring, quinazoline ring, naphthyridine ring, phenanthridine ring, carbazole ring, dibenzofuran ring, dibenzothiophene ring, and preferably pyridine ring, pyrimidine ring, triazine ring, carbazole ring, dibenzofuran ring, dibenzothiophene ring.

[0301] When Ar 201 , Ar 202 , Ar 203 is a carbazole ring which may have substituents, the N-position of the carbazole ring preferably has substituents or is bonded to the adjacent structure.

[0302] When Ar 202 is an aliphatic hydrocarbon structure which may have substituents, it is an aliphatic hydrocarbon structure having a straight-chain, branched-chain or cyclic structure, preferably having 1 or more and 24 or less carbon atoms, more preferably 1 or more and 12 or less carbon atoms, and still more preferably 1 or more and 8 or less carbon atoms.

[0303] (i1, i2, i3, i4, k1, k2) i1 and i2 each independently represent an integer from 0 to 12, preferably from 1 to 12, more preferably from 1 to 8, and still more preferably from 1 to 6. Within this range, an improvement in solubility or charge transportability is expected. i3 represents an integer preferably from 0 to 5, more preferably from 0 to 2, and still more preferably 0 or 1. i4 represents an integer preferably from 0 to 2, more preferably 0 or 1. k1 and k2 each independently represent an integer preferably from 0 to 3, more preferably from 1 to 3, still more preferably 1 or 2, and particularly preferably 1.

[0304] (Ar 201 、Ar 202 、Ar 203 's preferred substituents) Ar 201 、Ar 202 、Ar 203 The substituents that can be possessed can be arbitrarily selected, but are preferably one or more substituents selected from the substituent group S. The preferred groups are also as shown in the substituent group S, but more preferably unsubstituted (hydrogen atom), alkyl, aryl, particularly preferably unsubstituted (hydrogen atom), alkyl, and most preferably unsubstituted (hydrogen atom) or tert-butyl. Preferably, tert-butyl is substituted in Ar 203 when Ar 203 is present, and is substituted in Ar 203 when Ar 202 is absent, and is substituted in Ar 202 and Ar 203 when both are absent, and is substituted in Ar 201 .

[0305] (Preferred form of the compound represented by formula (201)) The compound represented by formula (201) is preferably a compound that satisfies any one or more of the following (I) to (IV).

[0306] (I) Phenyl linkage type The structure represented by formula (202) preferably has a structure in which benzene rings are connected, that is, a benzene ring structure, where i1 is from 1 to 6 and at least one of the benzene rings is bonded to an adjacent structure at the ortho or meta position. With such a structure, an improvement in solubility and an improvement in charge transportability can be expected.

[0307] (II) (Phenyl)-aralkyl (alkyl) A structure having an aromatic hydrocarbon ring group or an aromatic heterocyclic group to which an alkyl or aralkyl is bonded on ring A1 or ring A2, that is, Ar 201 is an aromatic hydrocarbon ring structure or an aromatic heterocyclic structure, i1 is from 1 to 6, Ar 202 is an aliphatic hydrocarbon structure, i2 is from 1 to 12, preferably from 3 to 8, Ar 203 is a benzene ring structure, and i3 is 0 or 1. Preferably, Ar 201 is the aromatic hydrocarbon ring structure, more preferably a structure formed by connecting 1 to 5 benzene rings, and still more preferably 1 benzene ring. With such a structure, an improvement in solubility and an improvement in charge transportability can be expected.

[0308] (III) Dendron A structure in which a dendron is bonded to ring A1 or ring A2, for example, Ar 201 、Ar 202 is a benzene ring structure, Ar 203 is a biphenyl or terphenyl structure, i1, i2 are 1 to 6, i3 is 2, and j is 2. By having such a structure, an improvement in solubility and an improvement in charge transportability can be expected.

[0309] (IV) B 201 -L 200 -B 202 The structure represented by B 201 -L 200 -B 202 is preferably a structure represented by formula (203) or formula (204) below.

[0310] [Chemical formula 11]

[0311] In formula (203), R 211 、R 212 、R 213 each independently represents a substituent. In formula (204), ring B3 represents an aromatic heterocyclic structure containing a nitrogen atom which may have a substituent. Ring B3 is preferably a pyridine ring.

[0312] (Preferred phosphorescent materials) As the phosphorescent material represented by formula (201), there is no particular limitation, and the following can be cited as preferred phosphorescent materials.

[0313] [Chemical formula 12]

[0314] [Chemical formula 13]

[0315] In addition, a phosphorescent material represented by formula (205) below is also preferred.

[0316] [Chemical formula 14]

[0317] [In formula (205), M 2 represents a metal, and T represents a carbon atom or a nitrogen atom. R 92 ~R 95 each independently represents a substituent. Among them, when T is a nitrogen atom, R does not exist94 and R 95

[0318] In formula (205), as specific examples of M 2 metals selected from Groups 7 to 11 of the periodic table can be cited. Among them, preferably cited are: ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum or gold, and particularly preferably cited are divalent metals such as platinum and palladium.

[0319] In addition, in formula (205), R 92 and R 93 each independently represent a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an alkenyl group, a cyano group, an amino group, an acyl group, an alkoxycarbonyl group, a carboxyl group, an alkoxy group, an alkylamino group, an aralkylamino group, a haloalkyl group, a hydroxyl group, an aryloxy group, an aromatic hydrocarbon ring group or an aromatic heterocyclic group.

[0320] Furthermore, when T is a carbon atom, R 94 and R 95 each independently represent substituents represented by the same examples as those of R 92 and R 93 In addition, when T is a nitrogen atom, there is no R 94 or R 95 directly bonded to this T. In addition, R 92 to R 95 can further have substituents. As the substituents, the above-mentioned substituents can be used. Furthermore, any two or more groups among R 92 to R 95 can be connected to each other to form a ring.

[0321] (Molecular weight) The molecular weight of the phosphorescent light-emitting material is preferably 5000 or less, more preferably 4000 or less, and particularly preferably 3000 or less. In addition, the molecular weight of the phosphorescent light-emitting material is preferably 800 or more, more preferably 1000 or more, and further preferably 1200 or more. It is considered that by being within this molecular weight range, the phosphorescent light-emitting materials can be uniformly mixed with the charge transport material without agglomeration, and a light-emitting layer with high luminous efficiency can be obtained.

[0322] In terms of the high heat resistance of the phosphorescent light-emitting material and the formed light-emitting layer based on Tg or melting point, decomposition temperature, etc., and in terms of not easily causing film quality degradation or an increase in impurity concentration accompanying thermal decomposition of the material due to gas generation, recrystallization, molecular migration, etc., the molecular weight of the phosphorescent light-emitting material is preferably large. On the other hand, in terms of the easy purification of organic compounds, the molecular weight of the phosphorescent light-emitting material is preferably small.

[0323] <Charge transport material> ​The charge transport material used in the light-emitting layer is a material having a skeleton with excellent charge transport properties, and is preferably selected from an electron transport material, a hole transport material, and an ambipolar material capable of transporting both electrons and holes.

[0324] Specific examples of the skeleton with excellent charge transport properties include: an aromatic structure, an aromatic amine structure, a triarylamine structure, a dibenzofuran structure, a naphthalene structure, a phenanthrene structure, a phthalocyanine structure, a porphyrin structure, a thiophene structure, a benzylphenyl structure, a fluorene structure, a quinacridone structure, a triphenylene structure, a carbazole structure, a pyrene structure, an anthracene structure, a phenanthroline structure, a quinoline structure, a pyridine structure, a pyrimidine structure, a triazine structure, an oxadiazole structure, or an imidazole structure, etc.

[0325] As the electron transport material, from the viewpoint of a material having excellent electron transport properties and relatively stable structure, compounds having a pyridine structure, a pyrimidine structure, or a triazine structure are more preferred, and compounds having a pyrimidine structure or a triazine structure are further preferred.

[0326] The hole transport material is a compound having a structure with excellent hole transport properties. Among the central skeletons with excellent charge transport properties, a carbazole structure, a dibenzofuran structure, a triarylamine structure, a naphthalene structure, a phenanthrene structure, or a pyrene structure is preferred as the structure with excellent hole transport properties, and a carbazole structure, a dibenzofuran structure, or a triarylamine structure is further preferred.

[0327] The charge transport material used in the light-emitting layer preferably has a condensed ring structure of three or more rings, and further preferably a compound having two or more condensed ring structures of three or more rings or a compound having at least one condensed ring of five or more rings. By using these compounds, the following effects can be easily obtained: the rigidity of the molecule increases, and the degree of molecular motion in response to heat is suppressed. Further, from the aspects of charge transport properties and material durability, the condensed rings of three or more rings and the condensed rings of five or more rings preferably have an aromatic hydrocarbon ring or an aromatic heterocycle.

[0328] Specific examples of the condensed ring structure of three or more rings include: an anthracene structure, a phenanthrene structure, a pyrene structure, structure, a naphthacene structure, a triphenylene structure, a fluorene structure, a benzo[fluorene] structure, an indeno[fluorene] structure, an indolo[fluorene] structure, a carbazole structure, an indeno[carbazole] structure, an indolo[carbazole] structure, a dibenzofuran structure, a dibenzothiophene structure, etc. From the viewpoints of charge transport properties and solubility, at least one selected from the group consisting of a phenanthrene structure, a fluorene structure, an indeno[fluorene] structure, a carbazole structure, an indeno[carbazole] structure, an indolo[carbazole] structure, a dibenzofuran structure, and a dibenzothiophene structure is preferred, and from the viewpoint of durability against charge, a carbazole structure or an indolo[carbazole] structure is further preferred.

[0329] In the present invention, from the viewpoint of the durability of charges in the organic electroluminescent element, it is preferable that at least one of the charge transport materials in the light-emitting layer is a material having a pyrimidine skeleton or a triazine skeleton.

[0330] From the viewpoint of excellent flexibility, the charge transport material of the light-emitting layer is preferably a polymer material. The light-emitting layer formed using a material with excellent flexibility is preferably used as the light-emitting layer of the organic electroluminescent element formed on the flexible substrate. When the charge transport material contained in the light-emitting layer is a polymer material, the molecular weight is preferably 5,000 or more and 1,000,000 or less, more preferably 10,000 or more and 500,000 or less, and still more preferably 10,000 or more and 100,000 or less.

[0331] In addition, from the viewpoints of ease of synthesis and purification, ease of design of electron transport performance and hole transport performance, and ease of viscosity adjustment when dissolved in a solvent, the charge transport material of the light-emitting layer is preferably a low molecule. When the charge transport material contained in the light-emitting layer is a low molecular material, the molecular weight is preferably 5,000 or less, more preferably 4,000 or less, particularly preferably 3,000 or less, most preferably 2,000 or less, preferably 300 or more, more preferably 350 or more, and still more preferably 400 or more.

[0332] <Fluorescent light-emitting material> As the fluorescent light-emitting material, there is no particular limitation, and a compound represented by the following formula (211) is preferred.

[0333] [Chemical formula 15]

[0334] In the above formula (211), Ar 241 represents an aromatic hydrocarbon condensed ring structure which may have a substituent, and Ar 242 , Ar 243 each independently represents an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group which may have a substituent, or a group bonded thereto. n41 is an integer of 1 to 4.

[0335] Ar 241 represents an aromatic hydrocarbon condensed ring structure preferably having 10 to 30 carbon atoms. As specific ring structures, examples include: naphthalene, acenaphthene, fluorene, anthracene, phenanthrene, fluoranthene, pyrene, tetracene, perylene, etc. Ar 241 is more preferably an aromatic hydrocarbon condensed ring structure having 12 to 20 carbon atoms. As specific ring structures, examples include: acenaphthene, fluorene, anthracene, phenanthrene, fluoranthene, pyrene, tetracene, perylene. Ar 241More preferably, it is an aromatic hydrocarbon condensed ring structure having 16 to 18 carbon atoms. As specific ring structures, examples include: fluoranthene, pyrene,

[0336] n41 is from 1 to 4, preferably from 1 to 3, more preferably from 1 to 2, and most preferably 2.

[0337] As Ar 242 、Ar 243 The alkyl group is preferably an alkyl group having 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms. As Ar 242 、Ar 243 The aromatic hydrocarbon ring group is preferably an aromatic hydrocarbon ring group having 6 to 30 carbon atoms, more preferably an aromatic hydrocarbon ring group having 6 to 24 carbon atoms, and most preferably a phenyl group or a naphthyl group. As Ar 242 、Ar 243 The aromatic heterocyclic group is preferably an aromatic heterocyclic group having 3 to 30 carbon atoms, more preferably an aromatic hydrocarbon ring group having 5 to 24 carbon atoms, and specifically preferably a carbazolyl group, a dibenzofuranyl group, or a dibenzothiophenyl group, and more preferably a dibenzofuranyl group.

[0338] Ar 241 、Ar 242 、Ar 243 The substituents that Ar 241 、Ar 242 、Ar 243 can have are preferably groups selected from the substituent group S, more preferably hydrocarbon groups contained in the substituent group S, and further preferably hydrocarbon groups among the groups preferably used as the substituent group S.

[0339] The charge transport material used together with the above-mentioned fluorescent light-emitting material is not particularly limited, and preferably a material represented by the following formula (212).

[0340] [Chemical formula 16]

[0341] In the above formula (212), R 251 、R 252 are each independently a structure represented by the formula (213), R 253 represents a substituent, and when there are a plurality of R 253 , they may be the same or different, and n43 is an integer from 0 to 8.

[0342] [Chemical formula 17]

[0343] In the above formula (213), * represents the bonding site to the anthracene ring of the formula (212), Ar 254 、Ar 255Each independently represents an aromatic hydrocarbon ring structure which may have substituents or an aromatic heterocyclic ring structure which may have substituents. In Ar 254 and Ar 255 When there are a plurality of them respectively, they may be the same or different. n44 is an integer from 1 to 5, and n45 is an integer from 0 to 5.

[0344] Ar 254 Preferably, it is a monocyclic or condensed-ring aromatic hydrocarbon ring structure having 6 to 30 carbon atoms which may have substituents, and more preferably, it is a monocyclic or condensed-ring aromatic hydrocarbon ring structure having 6 to 12 carbon atoms which may have substituents.

[0345] Ar 255 Preferably, it is a monocyclic or condensed-ring aromatic hydrocarbon ring structure having 6 to 30 carbon atoms which may have substituents, or a condensed-ring aromatic heterocyclic ring structure having 6 to 30 carbon atoms which may have substituents. Ar 255 More preferably, it is a monocyclic or condensed-ring aromatic hydrocarbon ring structure having 6 to 12 carbon atoms which may have substituents, or a condensed-ring aromatic heterocyclic ring structure having 12 carbon atoms which may have substituents.

[0346] n44 is preferably an integer from 1 to 3, and more preferably 1 or 2. n45 is preferably an integer from 0 to 3, and more preferably from 0 to 2.

[0347] R as a substituent 253 and Ar 254 and Ar 255 The substituents which can be had are preferably groups selected from the substituent group S. More preferably, they are hydrocarbon groups contained in the substituent group S, and further preferably, they are hydrocarbon groups among the groups preferably used as the substituent group S.

[0348] The molecular weights of the fluorescent light-emitting material and the charge transport material are preferably 5,000 or less, more preferably 4,000 or less, particularly preferably 3,000 or less, and most preferably 2,000 or less. In addition, they are preferably 300 or more, more preferably 350 or more, and further preferably 400 or more.

[0349] [Hole blocking layer] A hole blocking layer 106 may be provided between the light-emitting layer 105 and the electron injection layer 108 described later. The hole blocking layer 106 is a layer which also further functions to block holes moving from the anode 102 from reaching the cathode 109 in the electron transport layer. The hole blocking layer 106 is a layer laminated on the light-emitting layer 105 so as to be in contact with the interface on the cathode 109 side of the light-emitting layer 105.

[0350] The hole blocking layer 106 has the function of blocking holes moving from the anode 102 from reaching the cathode 109 and the function of effectively transporting electrons injected from the cathode 109 in the direction of the light emitting layer 105.

[0351] As the physical properties required for the material constituting the hole blocking layer 106, the following can be cited: high electron mobility and low hole mobility, large energy gap (the difference between HOMO and LUMO), high triplet excitation energy level (T1), etc. As materials for the hole blocking layer 106 that satisfy such conditions, for example, mixed ligand complexes such as bis(2-methyl-8-hydroxyquinoline)(phenol)aluminum and bis(2-methyl-8-hydroxyquinoline)(triphenylsilanol)aluminum, metal complexes such as bis(2-methyl-8-hydroxyquinoline)aluminum-μ-oxo-bis-(2-methyl-8-hydroxyquinoline)aluminum dinuclear metal complex, styryl compounds such as stilbenylbiphenyl derivatives (Japanese Patent Laid-Open No. 11-242996), triazole derivatives such as 3-(4-biphenylyl)-4-phenyl-5(4-tert-butylphenyl)-1,2,4-triazole (Japanese Patent Laid-Open No. 7-41759), phenanthroline derivatives such as bathocuproine (Japanese Patent Laid-Open No. 10-79297), etc. Further, compounds having at least one pyridine ring substituted at the 2, 4, and 6 positions described in International Publication No. 2005 / 022962 are also preferably used as materials for the hole blocking layer 106.

[0352] There is no limitation on the method for forming the hole blocking layer 106. The hole blocking layer 106 can be formed by a wet film forming method, a vapor deposition method, or other methods. As long as the effects of the present invention are not significantly impaired, the film thickness of the hole blocking layer 106 can be arbitrary. The film thickness of the hole blocking layer 106 is usually 0.3 nm or more, preferably 0.5 nm or more, usually 100 nm or less, and preferably 50 nm or less.

[0353] [Electron transport layer] The electron transport layer 107 is a layer provided between the light emitting layer 105 and the cathode 109 for transporting electrons.

[0354] As the electron transport material of the electron transport layer 107, a compound is generally used which has a high electron injection efficiency from the cathode 109 or an adjacent layer on the cathode 109 side and has a high electron mobility and can effectively transport the injected electrons. As a compound satisfying such conditions, for example, metal complexes such as aluminum complexes or lithium complexes of 8-hydroxyquinoline (Japanese Patent Laid-Open No. Sho 59-194393), metal complexes of 10-hydroxybenzo[h]quinoline, oxadiazole derivatives, stilbenyl biphenyl derivatives, silole derivatives, 3-hydroxyflavone metal complexes, 5-hydroxyflavone metal complexes, benzoxazole metal complexes, benzothiazole metal complexes, tribenzimidazolylbenzene (U.S. Patent No. 5645948), quinoxaline compounds (Japanese Patent Laid-Open No. Hei 6-207169), phenanthroline derivatives (Japanese Patent Laid-Open No. Hei 5-331459), 2-tert-butyl-9,10-N,N'-dicyanoanthraquinone diimide, triazine compound derivatives, n-type hydrogenated amorphous silicon carbide, n-type zinc sulfide, n-type zinc selenide, etc. can be cited.

[0355] As the electron transport material used in the electron transport layer 107, by doping an alkali metal such as sodium, potassium, cesium, lithium, rubidium, etc. in an electron-transporting organic compound represented by a nitrogen-containing heterocyclic compound such as bathophenanthroline or a metal complex such as an aluminum complex of 8-hydroxyquinoline (described in Japanese Patent Laid-Open No. Hei 10-270171, Japanese Patent Laid-Open No. 2002-100478, Japanese Patent Laid-Open No. 2002-100482, etc.), it is possible to balance electron injection and transport properties and excellent film quality, and thus it is preferred. In addition, doping an inorganic salt such as lithium fluoride or cesium carbonate in the above-mentioned electron-transporting organic compound is also effective.

[0356] There is no limitation on the formation method of the electron transport layer 107. The electron transport layer 107 can be formed by a wet film-forming method, a vapor deposition method or other methods.

[0357] As long as the effects of the present invention are not significantly impaired, the film thickness of the electron transport layer 107 can be arbitrary. The film thickness of the electron transport layer 107 is generally 1 nm or more, preferably 5 nm or more, generally 300 nm or less, and preferably 100 nm or less.

[0358] [Electron injection layer] In order to effectively inject the electrons injected from the cathode 109 into the light-emitting layer 105, an electron injection layer 108 can be provided between the electron transport layer 107 and the cathode 109 described later. The electron injection layer 108 is composed of an inorganic salt or the like.

[0359] Examples of the material for the electron injection layer 108 include lithium fluoride (LiF), magnesium fluoride (MgF2), lithium oxide (Li2O), cesium (II) carbonate (CsCO3), etc. (see Applied Physics Letters, 1997, Vol. 70, p. 152; Japanese Patent Laid-Open No. 10-74586; IEEE Transactions on Electron Devices, 1997, Vol. 44, p. 1245; SID 04 Digest, p. 154, etc.).

[0360] The electron injection layer 108 generally does not have charge transport properties. Therefore, in order to efficiently inject electrons, it is preferably made into an extremely thin film, and its film thickness is usually 0.1 nm or more, preferably 5 nm or less.

[0361] [Cathode] The cathode 109 is an electrode that functions to inject electrons into the layer on the light-emitting layer 105 side.

[0362] Examples of the material for the cathode 109 generally include metals such as aluminum, gold, silver, nickel, palladium, platinum, metal oxides such as oxides of indium and / or tin, metal halides such as copper iodide, carbon black, or conductive polymers such as poly(3-methylthiophene), polypyrrole, and polyaniline. Among these, in order to effectively inject electrons, a metal with a low work function is preferred. For example, appropriate metals such as tin, magnesium, indium, calcium, aluminum, silver, or their alloys are used. As specific examples, alloy electrodes with a low work function such as magnesium-silver alloy, magnesium-indium alloy, and aluminum-lithium alloy can be cited.

[0363] The material of the cathode 109 can use only one kind, or two or more kinds can be used in any combination and ratio.

[0364] The film thickness of the cathode 109 varies depending on the required transparency. In the case where transparency is required, the transmittance of visible light is usually set to 60% or more, preferably 80% or more. In this case, the thickness of the cathode 109 is usually 5 nm or more, preferably 10 nm or more, usually 1000 nm or less, preferably about 500 nm or less. In the case where it can be opaque, the thickness of the cathode 109 can be arbitrary, and the cathode can be the same as the substrate.

[0365] Different conductive materials can also be laminated on the cathode 9. For example, for the purpose of protecting a cathode including a low work function metal composed of an alkali metal such as sodium or cesium, an alkaline earth metal such as barium or calcium, etc., a metal layer having a high work function and being stable with respect to the atmosphere is further laminated thereon, so that the stability of the element is increased, which is therefore preferable. For this purpose, for example, metals such as aluminum, silver, copper, nickel, chromium, gold, platinum, etc. are used. These materials can be used alone, or two or more kinds can be used in any combination and ratio.

[0366] [Other layers] Within the scope not departing from its gist, the organic electroluminescent element of the present invention can have other configurations. For example, as long as its performance is not impaired, between the anode 102 and the cathode 109, any layer other than the layers described above can be provided, and in addition, non-essential layers in the layers described above can be simplified.

[0367] In addition, one or more than two layers of other organic layers can be provided on the upper layer of the cathode 109 as a protective layer for the cathode.

[0368] In the layer configuration described above, the components other than the substrate can also be laminated in the reverse order. For example, if it is Figure 1 the layer configuration, the cathode 109, the electron injection layer 108, the electron transport layer 107, the hole blocking layer 106, the light emitting layer 105, the hole transport layer 104, the hole injection layer 103, and the anode 102 can be sequentially provided on the substrate 101 as other components.

[0369] The organic electroluminescent element or the organic EL display panel of the present invention can be configured as a single organic electroluminescent element, can also be applied to a configuration in which a plurality of organic electroluminescent elements are arranged in an array, and can also be applied to a configuration in which the anode and the cathode are arranged in an X-Y matrix.

[0370] As long as the effects of the present invention are not significantly impaired, the above-mentioned each layer can also contain components other than those described as materials.

[0371] [Organic electroluminescent device] Two organic electroluminescent elements that emit light in mutually different colors or an organic EL display panel including two organic electroluminescent elements that emit light in mutually different colors can be used to fabricate an organic electroluminescent device such as an organic EL display device or an organic EL illumination. In this organic electroluminescent device, by using at least one, preferably all, of the organic electroluminescent elements as the organic electroluminescent elements of the present invention or by using the organic EL display panel of the present invention including the above-mentioned organic electroluminescent elements as at least one, preferably all, of the organic electroluminescent elements, a high-quality organic electroluminescent device can be provided.

[0372] <Organic EL display device> There are no particular restrictions on the style or structure of the organic EL display device using the organic electroluminescent element or the organic EL display panel of the present invention. The organic electroluminescent element or the organic EL display panel of the present invention can be used and assembled according to common methods. For example, the method described in "Organic EL Displays" (published by Ohmsha, Ltd. on August 20, 2004, written by Seishi Toki, Chihaya Adachi, and Hideyuki Murata) can be used to form the organic EL display device.

[0373] <Organic EL Lighting> There are no particular restrictions on the style or structure of the organic EL lighting using the organic electroluminescent element of the present invention. The organic electroluminescent element of the present invention or the organic EL display panel of the present invention including the above-mentioned organic electroluminescent element can be used and assembled according to common methods.

[0374] [Manufacturing Method of Organic Electroluminescent Element and Organic EL Display Panel] As one mode, the organic electroluminescent element or the organic EL display panel of the present invention is manufactured by the following method, which is a method including the following process group (ii) after the following process group (i) or including the following process group (i) after the following process group (ii), or using the above-mentioned design method. Process group (i) sequentially includes: a process of printing a functional ink for forming functional layer 1 onto a divided region by an inkjet method; a process of subjecting the printed divided region to reduced-pressure drying in a vacuum chamber; a process of baking the dried divided region. Process group (ii) sequentially includes: a process of printing a functional ink for forming functional layer 2 onto a divided region by an inkjet method; a process of subjecting the printed divided region to reduced-pressure drying in a vacuum chamber; a process of baking the dried divided region.

[0375] Since the solvent during film formation is easily removed, the lower limit value of the pressure in the reduced-pressure drying is preferably 1×10 1 Pa or less, more preferably 1×10 0 Pa or less, and further preferably 1×10 -1 Pa or less.

[0376] The reduced-pressure drying can be carried out while heating. In this case, since the solvent during film formation is easily removed, the temperature is preferably 10°C or higher, more preferably 15°C or higher, and further preferably 20°C or higher. In addition, from the viewpoint of preventing the solvent contained in the ink from boiling suddenly, the temperature in the reduced-pressure drying is preferably 200°C or lower, more preferably 190°C or lower, and further preferably 180°C or lower.

[0377] In order to moderately spend a long time to lower the needle position of the functional ink and avoid the continuous contact between the organic solvent and the dam for too long, the time of reduced-pressure drying is preferably more than 1 minute and less than 15 minutes, more preferably more than 2 minutes and less than 12 minutes, and still more preferably more than 3 minutes and less than 10 minutes.

[0378] As one mode, at least one of the functional ink for forming the functional layer 1 and the functional ink for forming the functional layer 2 of the organic electroluminescent element or the organic EL display panel of the present invention may contain two or more organic solvents. In this case, in the above process groups (i) and (ii), in the process of subjecting the divided region to reduced-pressure drying in a vacuum chamber in the process group using the functional ink containing two or more organic solvents, when the pressure reaches lower than the vapor pressure of the organic solvent having the lowest vapor pressure among the two or more organic solvents, the time is not particularly limited, and it is preferably 60 seconds or more after the start of reduced-pressure drying. In addition, when the pressure reaches lower than the vapor pressure of the organic solvent having the lowest vapor pressure among the two or more organic solvents, the time is not particularly limited, and it is preferably 1800 seconds or less.

[0379] When both the functional ink for forming the functional layer 1 and the functional ink for forming the functional layer 2 contain two or more organic solvents, in the process of subjecting the divided region to reduced-pressure drying in a vacuum chamber included in at least one of the above process groups (i) and (ii), when the pressure reaches lower than the vapor pressure of the organic solvent having the lowest vapor pressure among the two or more organic solvents, the time preferably satisfies the above range. In addition, in the processes of subjecting the divided region to reduced-pressure drying included in both of the above process groups (i) and (ii), when the pressure reaches lower than the vapor pressure of the organic solvent having the lowest vapor pressure among the two or more organic solvents, the time more preferably satisfies the above range. Examples

[0380] Hereinafter, embodiments will be shown to further describe the present invention in detail. However, the present invention is not limited to the following examples, and the present invention can be implemented with any changes as long as it does not deviate from its gist.

[0381] <Preparation of Functional Ink> (Preparation of Functional Ink 1) The polymer compound (P-1) (weight-average molecular weight: about 15,200) represented by the following structural formula was mixed with 1,1-diphenylhexane (boiling point: about 320 °C) in a screw-cap bottle to a concentration of 2.3% by weight. Then, the screw-cap bottle was placed in a vacuum chamber, and the evacuation and nitrogen filling were repeated three times to replace the gas part in the screw-cap bottle with nitrogen. Then, while stirring at 420 rpm using a magnetic stirrer, it was heated at a hot plate temperature of 110 °C for 3 hours. After cooling the resulting composition to around room temperature, it was filtered using a membrane filter with a pore size of 0.2 μm to obtain Functional Ink 1.

[0382] [Chemical formula 18]

[0383] (Preparation of Functional Ink 2) The polymer compound (P-1) was mixed with 1,1-diphenylpentane (boiling point: about 307 °C, vapor pressure) in a screw-cap bottle to a concentration of 2.3% by weight. Then, the screw-cap bottle was placed in a vacuum chamber, and the evacuation and nitrogen filling were repeated three times to replace the gas part in the screw-cap bottle with nitrogen. Then, while stirring at 420 rpm using a magnetic stirrer, it was heated at a hot plate temperature of 110 °C for 3 hours. After cooling the resulting composition to around room temperature, it was filtered using a membrane filter with a pore size of 0.2 μm to obtain Functional Ink 2.

[0384] (Preparation of Functional Ink 3) The polymer compound (P-1) and the electron-accepting compound (HI-1) represented by the following structural formula were weighed in a weight ratio of (P-1):(HI-1) = 87:13 as Hole Injection Material 1. Hole Injection Material 1 was mixed with n-butyl benzoate (boiling point: about 250 °C) in a screw-cap bottle to a concentration of 2.3% by weight. Then, the screw-cap bottle was placed in a vacuum chamber, and the evacuation and nitrogen filling were repeated three times to replace the gas part in the screw-cap bottle with nitrogen. Then, while stirring at 420 rpm using a magnetic stirrer, it was heated at a hot plate temperature of 110 °C for 3 hours. After cooling the resulting composition to around room temperature, it was filtered using a membrane filter with a pore size of 0.2 μm to obtain Functional Ink 3.

[0385] [Chemical formula 19]

[0386] (Preparation of Functional Ink 4) The hole injection material 1 was mixed with 1,1-diphenylpentane (boiling point: about 307 °C) in a screw-capped bottle in such a way as to be 2.3% by weight, and then the screw-capped bottle was placed in a vacuum chamber. The evacuation and nitrogen filling were repeated 3 times to displace the gas part in the screw-capped bottle with nitrogen. Then, while stirring at 420 rpm using a magnetic stirrer, it was heated at a hot plate temperature of 110 °C for 3 hours. After cooling the obtained composition to around room temperature, it was filtered using a membrane filter with a pore size of 0.2 μm to obtain the functional ink 4.

[0387] (Preparation of functional ink 5) The polymer compound (P-1) and the electron-accepting compound (HI-1) were weighed in such a way that the weight ratio was (P-1):(HI-1) = 89:11 as the hole injection material 2. Next, ethyl-4-methylbenzoate (boiling point: about 232 °C, vapor pressure: about 6.6 Pa) and 4-butylbiphenyl (boiling point: about 318 °C) were mixed in such a way that the weight ratio was 70:30 as the mixed solvent 1. The hole injection material 2 was mixed with the mixed solvent 1 in a screw-capped bottle in such a way as to be 2.3% by weight, and then the screw-capped bottle was placed in a vacuum chamber. The evacuation and nitrogen filling were repeated 3 times to displace the gas part in the screw-capped bottle with nitrogen. Then, while stirring at 420 rpm using a magnetic stirrer, it was heated at a hot plate temperature of 110 °C for 3 hours. After cooling the obtained composition to around room temperature, it was filtered using a membrane filter with a pore size of 0.2 μm to obtain the functional ink 5.

[0388] (Preparation of functional ink 6) Ethyl-4-methylbenzoate (boiling point: about 232 °C, vapor pressure: about 6.6 Pa) and γ-decalactone (boiling point: about 281 °C) were mixed in such a way that the weight ratio was 70:30 as the mixed solvent 2. The hole injection material 2 was mixed with the mixed solvent 2 in a screw-capped bottle in such a way as to be 2.3% by weight, and then the screw-capped bottle was placed in a vacuum chamber. The evacuation and nitrogen filling were repeated 3 times to displace the gas part in the screw-capped bottle with nitrogen. Then, while stirring at 420 rpm using a magnetic stirrer, it was heated at a hot plate temperature of 110 °C for 3 hours. After cooling the obtained composition to around room temperature, it was filtered using a membrane filter with a pore size of 0.2 μm to obtain the functional ink 6.

[0389] (Preparation of functional ink 7) A low-molecular compound (M-1) represented by the following structural formula, a high-molecular compound (P-2) represented by the following structural formula, and HI-1 are weighed in a weight ratio of (P-2):(M-1):(HI-1) = 64:21:15 as the hole injection material 3. Next, n-butyl benzoate (boiling point: about 250 °C), 2-ethylhexyl benzoate (boiling point: about 296.5 °C), and benzyl benzyl benzoate (boiling point: about 324 °C) are mixed in a weight ratio of 70:20:10 as the mixed solvent 3. The hole injection material 3 is mixed with the mixed solvent 3 in a screw-capped bottle to be 2.3% by weight, and then the screw-capped bottle is placed in a vacuum chamber. The evacuation and nitrogen filling are repeated 3 times to replace the gas part in the screw-capped bottle with nitrogen. Then, while stirring at 420 rpm using a magnetic stirrer, it is heated at a hot plate temperature of 110 °C for 3 hours. After cooling the obtained composition to around room temperature, it is filtered using a membrane filter with a pore size of 0.2 μm to obtain the functional ink 7.

[0390] [Chemical formula 20]

[0391] [Chemical formula 21]

[0392] (Preparation of functional ink 8) A high-molecular compound (P-3) (average molecular weight of about 18,000) represented by the following structural formula is mixed with the mixed solvent 3 in a screw-capped bottle to be 2.3% by weight, and then the screw-capped bottle is placed in a vacuum chamber. The evacuation and nitrogen filling are repeated 3 times to replace the gas part in the screw-capped bottle with nitrogen. Then, while stirring at 420 rpm using a magnetic stirrer, it is heated at a hot plate temperature of 110 °C for 3 hours. After cooling the obtained composition to around room temperature, it is filtered using a membrane filter with a pore size of 0.2 μm to obtain the functional ink 8.

[0393] [Chemical formula 22]

[0394] (Preparation of functional ink 9) The high molecular compound (P-2), the low molecular compound (M-1), and the electron-accepting compound (HI-1) were weighed in a weight ratio of (P-2):(M-1):(HI-1) = 42.5:42.5:15 as the hole injection material 4. The hole injection material 4 was mixed with the mixed solvent 3 in a screw-capped bottle to a concentration of 2.3% by weight, and then the screw-capped bottle was placed in a vacuum chamber. The evacuation and nitrogen filling were repeated 3 times to replace the gas part in the screw-capped bottle with nitrogen. Then, while stirring at 420 rpm using a magnetic stirrer, it was heated at a hot plate temperature of 110 °C for 3 hours. After cooling the resulting composition to around room temperature, it was filtered using a membrane filter with a pore size of 0.2 μm to obtain the functional ink 9.

[0395] (Preparation of functional ink 10) The high molecular compound (P-3) (average molecular weight: about 40,000) was mixed with the mixed solvent 4 in a screw-capped bottle to a concentration of 2.0% by weight. The mixed solvent 4 was adjusted in a weight ratio of 2-ethylnaphthalene (boiling point: about 252 °C), 2-ethylhexyl benzoate (boiling point: about 296.5 °C), and benzyl benzoate (boiling point: about 324 °C) of 70:15:15. Then, the screw-capped bottle was placed in a vacuum chamber. The evacuation and nitrogen filling were repeated 3 times to replace the gas part in the screw-capped bottle with nitrogen. Then, while stirring at 420 rpm using a magnetic stirrer, it was heated at a hot plate temperature of 110 °C for 3 hours. After cooling the resulting composition to around room temperature, it was filtered using a membrane filter with a pore size of 0.2 μm to obtain the functional ink 10.

[0396] (Preparation of functional ink 11) The hole injection material 1 was mixed with the mixed solvent 5 in a screw-capped bottle to a concentration of 2.3% by weight. The mixed solvent 5 was prepared by mixing ethyl-4-methylbenzoate (boiling point: about 232 °C, vapor pressure: about 6.6 Pa) and diethyl sebacate (boiling point: about 309 °C) at a weight ratio of 70:30. Then, the screw-capped bottle was placed in a vacuum chamber. The evacuation and nitrogen filling were repeated 3 times to replace the gas part in the screw-capped bottle with nitrogen. Then, while stirring at 420 rpm using a magnetic stirrer, it was heated at a hot plate temperature of 110 °C for 3 hours. After cooling the resulting composition to around room temperature, it was filtered using a membrane filter with a pore size of 0.2 μm to obtain the functional ink 11.

[0397] (Preparation of functional ink 51) Weigh a polymer compound (P-51), a low molecular compound (M-51), and an electron-accepting compound (HI-51) represented by the following structural formula in a weight ratio of (P-51):(M-51):(HI-51) = 42.5:42.5:15 as the hole injection material 51. Next, mix n-butyl benzoate (boiling point: about 250 °C), 2-ethylhexyl benzoate (boiling point: about 296.5 °C), and benzyl benzoate (boiling point: about 324 °C) in a weight ratio of 70:20:10 as the mixed solvent 51. Mix the hole injection material 51 with the mixed solvent 51 in a screw-cap bottle to make it 2.3 wt%, then place it together with the screw-cap bottle in a vacuum chamber, repeat evacuation and nitrogen filling 3 times, and displace the gas part in the screw-cap bottle with nitrogen. Then, while stirring at 420 rpm using a magnetic stirrer, heat it at a hot plate temperature of 110 °C for 3 hours. After cooling the obtained composition to around room temperature, filter it using a membrane filter with a pore size of 0.2 μm to obtain the functional ink 51.

[0398] [Chemical formula 23]

[0399] [Chemical formula 24]

[0400] [Chemical formula 25]

[0401] (Preparation of functional ink 52) Mix a polymer compound (P-52) (average molecular weight: about 18,000) represented by the following structural formula with the mixed solvent 51 in a screw-cap bottle to make it 2.3 wt%, then place it together with the screw-cap bottle in a vacuum chamber, repeat evacuation and nitrogen filling 3 times, and displace the gas part in the screw-cap bottle with nitrogen. Then, while stirring at 420 rpm using a magnetic stirrer, heat it at a hot plate temperature of 110 °C for 3 hours. After cooling the obtained composition to around room temperature, filter it using a membrane filter with a pore size of 0.2 μm to obtain the functional ink 52.

[0402] [Chemical formula 26]

[0403] (Preparation of functional ink 53) Weigh a polymer compound (P-53) represented by the following structural formula and an electron-accepting compound (HI-51) in a weight ratio of (P-53):(HI-51) = 89:11 as the hole injection material 52. Then, mix the hole injection material 52 with the mixed solvent 51 in a screw-capped bottle to make it 2.3 wt%, and then place the screw-capped bottle in a vacuum chamber. Repeat the evacuation and nitrogen filling 3 times to replace the gas part in the screw-capped bottle with nitrogen. Then, while stirring at 420 rpm using a magnetic stirrer, heat it at a hot plate temperature of 110 °C for 3 hours. After cooling the obtained composition to around room temperature, filter it using a membrane filter with a pore size of 0.2 μm to obtain the functional ink 53.

[0404] [Chemical formula 27]

[0405] (Preparation of functional ink 54) Mix a polymer compound (P-52) (average molecular weight: about 18000) with the mixed solvent 52 in a screw-capped bottle to make it 2.0 wt%. The mixed solvent 52 is a mixture of 2-ethylnaphthalene (boiling point: about 252 °C), 2-ethylhexyl benzoate (boiling point: about 296.5 °C), and benzyl benzoate (boiling point: about 324 °C) in a weight ratio of 70:15:15. Then, place the screw-capped bottle in a vacuum chamber. Repeat the evacuation and nitrogen filling 3 times to replace the gas part in the screw-capped bottle with nitrogen. Then, while stirring at 420 rpm using a magnetic stirrer, heat it at a hot plate temperature of 110 °C for 3 hours. After cooling the obtained composition to around room temperature, filter it using a membrane filter with a pore size of 0.2 μm to obtain the functional ink 54.

[0406] (Preparation of functional ink 55) Weigh a polymer compound (P-51), a low-molecular compound (M-51), and an electron-accepting compound (HI-51) in a weight ratio of (P-51):(M-51):(HI-51) = 64:21:15 as the hole injection material 53. Mix the hole injection material 53 with the mixed solvent 51 in a screw-capped bottle to make it 2.3 wt%, and then place the screw-capped bottle in a vacuum chamber. Repeat the evacuation and nitrogen filling 3 times to replace the gas part in the screw-capped bottle with nitrogen. Then, while stirring at 420 rpm using a magnetic stirrer, heat it at a hot plate temperature of 110 °C for 3 hours. After cooling the obtained composition to around room temperature, filter it using a membrane filter with a pore size of 0.2 μm to obtain the functional ink 55.

[0407] <Preparation of the substrate> (Substrate A1) An indium tin oxide (ITO) film, a silver indium compound film, and an indium tin oxide film are sequentially formed on a glass substrate with a thickness of 0.7 mm by sputtering, and the pattern of the electrode is formed by a conventional photolithography method. A hydrophobic photosensitive resist is coated on this substrate to a thickness of 1.4 μm, and openings are formed using a conventional photolithography method. The size of the opening is about 202 μm in the major axis and about 82 μm in the minor axis.

[0408] (Substrate B1) An indium tin oxide (ITO) film, a silver indium compound film, and an indium tin oxide film are sequentially formed on a glass substrate with a thickness of 0.7 mm by sputtering, and the pattern of the electrode is formed by a conventional photolithography method. A hydrophobic photosensitive resist is coated on this substrate to a thickness of 1.3 μm, and openings are formed using a conventional photolithography method. The size of the opening is about 202 μm in the major axis and about 78 μm in the minor axis.

[0409] (Substrate C1) An indium tin oxide (ITO) film, a silver indium compound film, and an indium tin oxide film are sequentially formed on a glass substrate with a thickness of 0.7 mm by sputtering, and the pattern of the electrode is formed by a conventional photolithography method. A hydrophobic photosensitive resist is coated on this substrate to a thickness of 1.3 μm, and openings are formed using a conventional photolithography method. The size of the opening is about 210 μm in the major axis and about 86 μm in the minor axis.

[0410] (Substrate A2) An indium tin oxide (ITO) film, a silver indium compound film, and an indium tin oxide film are sequentially formed on a glass substrate with a thickness of 0.7 mm by sputtering, and the pattern of the electrode is formed by a conventional photolithography method. A hydrophobic photosensitive resist is coated on this substrate to a thickness of 1.3 μm, and openings are formed using a conventional photolithography method. The sizes of the various openings are all about 202 μm in the major axis and about 49, 75, and 102 μm respectively in the minor axis.

[0411] (Substrate B2) An indium tin oxide (ITO) film, a silver indium compound film, and an indium tin oxide film are sequentially formed on a glass substrate with a thickness of 0.7 mm by sputtering, and the pattern of the electrode is formed by a conventional photolithography method. A hydrophobic photosensitive resist is coated on this substrate to a thickness of 1.3 μm, and openings are formed using a conventional photolithography method. The size of the opening is about 210 μm in the major axis and about 86 μm in the minor axis.

[0412] (Substrate C2) An indium tin oxide (ITO) film, a silver indium compound film, and an indium tin oxide film are successively formed on a glass substrate with a film thickness of 0.7 mm by sputtering, and an electrode pattern is formed by a conventional photolithography method. A hydrophobic photosensitive resist is coated on this substrate to a film thickness of 1.3 μm, and openings are fabricated using a conventional photolithography method. The size of the openings is approximately 202 μm in the major axis and approximately 78 μm in the minor axis.

[0413] The obtained substrate is placed in ultrapure water and subjected to ultrasonic cleaning for 15 minutes, and then dried in a clean oven preheated to 130 °C for 10 minutes. In addition, immediately before coating the functional ink, it is baked on a hot plate heated to 230 °C for 10 minutes to remove the moisture adhering to the surface.

[0414] <Coating of functional ink> Each functional ink is filled into an inkjet printer cartridge (manufactured by Fujifilm Corporation, DMCLCP-11610) using a micropipette, and is coated on the openings of this substrate using an inkjet printer (manufactured by Fujifilm Corporation, DMP-2831). The ejection voltage of the inkjet printer is adjusted so that the amount of one drop of the functional ink ejected from the nozzle of the inkjet head is 10 pL.

[0415] (Fabrication of functional film 1) Functional ink 1 is coated on the openings that are 54 pixels in the minor axis direction and 32 pixels in the major axis direction of substrate A1, that is, a total of 1728 pixels, and then the following drying and baking processes are carried out to fabricate functional film 1. It should be noted that functional ink 1 is coated on one opening of substrate A1 by dropping 15 drops.

[0416] (Fabrication of functional film 2) Functional ink 2 is coated on the openings that are 54 pixels in the minor axis direction and 32 pixels in the major axis direction of substrate A1, that is, a total of 1728 pixels, and then the following drying and baking processes are carried out to fabricate functional film 2. It should be noted that functional ink 2 is coated on one opening of substrate A1 by dropping 15 drops.

[0417] (Fabrication of functional film 3) Functional ink 3 is coated on the openings that are 54 pixels in the minor axis direction and 32 pixels in the major axis direction of substrate A1, that is, a total of 1728 pixels, and then the following drying and baking processes are carried out to fabricate functional film 3. It should be noted that functional ink 3 is coated on one opening of substrate A1 by dropping 7 drops.

[0418] (Fabrication of functional film 4) Functional ink 4 is applied to an opening portion of 54 pixels in the short-axis direction and 32 pixels in the long-axis direction, i.e., a total of 1728 pixels, on substrate A1, and then a functional film 4 is produced by performing the following drying and baking processes. It should be noted that functional ink 4 is applied to one opening portion of substrate A1 by dropping 7 drops.

[0419] (Production of functional film 5) Functional ink 5 is applied to an opening portion of 54 pixels in the short-axis direction and 32 pixels in the long-axis direction, i.e., a total of 1728 pixels, on substrate A1, and then a functional film 5 is produced by performing the following drying and baking processes. It should be noted that functional ink 5 is applied to one opening portion of substrate A1 by dropping 9 drops.

[0420] (Production of functional film 6) Functional ink 6 is applied to an opening portion of 54 pixels in the short-axis direction and 32 pixels in the long-axis direction, i.e., a total of 1728 pixels, on substrate A1, and then a functional film 6 is produced by performing the following drying and baking processes. It should be noted that functional ink 6 is applied to one opening portion of substrate A1 by dropping 15 drops.

[0421] (Production of functional film 7) Functional ink 7 is applied to an opening portion of 45 pixels in the short-axis direction and 32 pixels in the long-axis direction, i.e., a total of 1440 pixels, on substrate B1, and then a functional film 7 is produced by performing the following drying and baking processes. It should be noted that functional ink 7 is applied to one opening portion of substrate B1 by dropping 19 drops.

[0422] (Production of functional film 8) Functional ink 8 is applied to an opening portion of 45 pixels in the short-axis direction and 32 pixels in the long-axis direction, i.e., a total of 1440 pixels, on substrate B1, and then a functional film 8 is produced by performing the following drying and baking processes. It should be noted that functional ink 8 is applied to one opening portion of substrate B1 by dropping 18 drops.

[0423] (Production of functional film 9) Functional ink 9 is applied to an opening portion of 45 pixels in the short-axis direction and 32 pixels in the long-axis direction, i.e., a total of 1440 pixels, on substrate B1, and then a functional film 9 is produced by performing the following drying and baking processes. It should be noted that functional ink 9 is applied to one opening portion of substrate B1 by dropping 10 drops.

[0424] (Production of functional film 10) Functional ink 8 is applied to an opening portion that is 45 pixels in the short-axis direction and 32 pixels in the long-axis direction, totaling 1440 pixels, on substrate B1. Then, by performing the following drying and baking processes, functional film 10 is fabricated. It should be noted that functional ink 8 is applied to one opening portion of substrate B1 by dropping 30 drops.

[0425] (Fabrication of functional film 11) Functional ink 8 is applied to an opening portion that is 45 pixels in the short-axis direction and 32 pixels in the long-axis direction, totaling 1440 pixels, on substrate B1 on which functional film 7 has been formed as described above. Then, by performing the following drying and baking processes, functional film 11 is fabricated. It should be noted that functional ink 8 is applied to one opening portion of substrate B1 on which functional film 7 has been formed as described above by dropping 18 drops.

[0426] (Fabrication of functional film 12) Functional ink 7 is applied to an opening portion that is 45 pixels in the short-axis direction and 32 pixels in the long-axis direction, totaling 1440 pixels, on substrate B1 on which functional film 8 has been formed as described above. Then, by performing the following drying and baking processes, functional film 12 is fabricated. It should be noted that functional ink 7 is applied to one opening portion of substrate B1 on which functional film 8 has been formed as described above by dropping 19 drops.

[0427] (Fabrication of functional film 13) Functional ink 9 is applied to an opening portion that is 22 pixels in the short-axis direction and 7 pixels in the long-axis direction, totaling 154 pixels, on substrate C1. Then, by performing the following drying and baking processes, functional film 13 is fabricated. It should be noted that functional ink 9 is applied to one opening portion of substrate C1 by dropping 4 drops.

[0428] (Fabrication of functional film 14) Functional ink 10 is applied to an opening portion that is 22 pixels in the short-axis direction and 7 pixels in the long-axis direction, totaling 154 pixels, on substrate C1. Then, by performing the following drying and baking processes, functional film 14 is fabricated. It should be noted that functional ink 10 is applied to one opening portion of substrate C1 by dropping 15 drops.

[0429] (Fabrication of functional film 15) Functional ink 10 is applied to an opening of 22 pixels in the short-axis direction and 7 pixels in the long-axis direction, totaling 154 pixels, on the substrate C1 having the functional film 13 formed thereon as described above. Then, by performing the following drying and baking processes, the functional film 15 is produced. It should be noted that functional ink 10 is applied to one opening of the substrate C1 having the functional film 13 formed thereon as described above in 15 drops.

[0430] (Fabrication of Functional Film 16) Functional ink 11 is applied to an opening of 54 pixels in the short-axis direction and 32 pixels in the long-axis direction, totaling 1728 pixels, on the substrate A1. Then, by performing the following drying and baking processes, the functional film 16 is produced. It should be noted that functional ink 11 is applied to one opening of the substrate A1 in 7 drops.

[0431] (Fabrication of Functional Film 17) Functional ink 2 is applied to an opening of 54 pixels in the short-axis direction and 32 pixels in the long-axis direction, totaling 1728 pixels, on the substrate A1. Then, by performing the following drying and baking processes, the functional film 17 is produced. It should be noted that functional ink 2 is applied to one opening of the substrate A1 in 14 drops.

[0432] (Fabrication of Functional Film 18) Functional ink 2 is applied to an opening of 54 pixels in the short-axis direction and 32 pixels in the long-axis direction, totaling 1728 pixels, on the substrate A1 having the functional film 16 formed thereon as described above. Then, by performing the following drying and baking processes, the functional film 18 is produced. It should be noted that functional ink 2 is applied to one opening of the substrate A1 having the functional film 16 formed thereon as described above in 14 drops.

[0433] (Fabrication of Functional Film 19) Functional ink 11 is applied to an opening of 54 pixels in the short-axis direction and 32 pixels in the long-axis direction, totaling 1728 pixels, on the substrate A1. Then, by performing the following drying and baking processes, the functional film 19 is produced. It should be noted that functional ink 11 is applied to one opening of the substrate A1 in 9 drops.

[0434] (Fabrication of Functional Film 20) Functional ink 2 is applied to an opening portion of 54 pixels in the short-axis direction and 32 pixels in the long-axis direction, i.e., a total of 1728 pixels, of the substrate A1 on which the functional film 19 is formed as described above. Then, by performing the following drying and baking processes, the functional film 20 is produced. It should be noted that the functional ink 2 is applied to one opening portion of the substrate A1 in such a way that 14 drops are dripped.

[0435] (Production of functional film 21) Functional ink 11 is applied to an opening portion of 54 pixels in the short-axis direction and 32 pixels in the long-axis direction, i.e., a total of 1728 pixels, of the substrate A1. Then, by performing the following drying and baking processes, the functional film 21 is produced. It should be noted that the functional ink 11 is applied to one opening portion of the substrate A1 in such a way that 15 drops are dripped.

[0436] (Production of functional film 22) Functional ink 2 is applied to an opening portion of 54 pixels in the short-axis direction and 32 pixels in the long-axis direction, i.e., a total of 1728 pixels, of the substrate A1 on which the functional film 21 is formed as described above. Then, by performing the following drying and baking processes, the functional film 22 is produced. It should be noted that the functional ink 2 is applied to one opening portion of the substrate A1 on which the functional film 21 is formed as described above in such a way that 14 drops are dripped.

[0437] (Production of functional films R1, G1, B1) Functional ink 51 is applied to one opening portion of the substrate A2 and to one divided area with an opening width of 49 μm in such a way that 4, 8, 12, 16, 20, 24 drops are dripped, to one divided area with an opening width of 75 μm in such a way that 5, 10, 15, 20, 25, 30 drops are dripped, and to one divided area with an opening width of 102 μm in such a way that 6, 12, 18, 24, 30, 36 drops are dripped. The area to be coated is an opening portion of 54 pixels in the short-axis direction and 15 pixels for each drop number in the long-axis direction, i.e., a total of 29160 pixels. Then, the following drying and sintering processes are performed to produce the functional films R1-1, R1-2, R1-3, R1-4, R1-5, R1-6, G1-1, G1-2, G1-3, G1-4, G1-5, G1-6, B1-1, B1-2, B1-3, B1-4, B1-5, B1-6.

[0438] (Production of functional films R2, G2, B2) The functional ink 52 is applied to one opening of the substrate A2 and to one divided area with an opening width of 49 μm by dripping 4, 8, 12, 16, 20 drops, to one divided area with an opening width of 75 μm by dripping 5, 10, 15, 20, 25, 30 drops, and to one divided area with an opening width of 102 μm by dripping 6, 12, 18, 24, 30, 36 drops. The area to be coated is an opening with 54 pixels in the short-axis direction and 15 pixels for each dripping number in the long-axis direction, that is, a total of 28350 pixels. Then, the following drying and sintering processes are carried out to fabricate the functional films R2-1, R2-2, R2-3, R2-4, R2-5, G2-1, G2-2, G2-3, G2-4, G2-5, G2-6, B2-1, B2-2, B2-3, B2-4, B2-5, B2-6.

[0439] (Fabrication of functional films R3, G3, B3) The functional ink 53 is applied to one opening of the substrate A2 and to one divided area with an opening width of 49 μm by dripping 4, 8, 12, 16, 20, 24 drops, to one divided area with an opening width of 75 μm by dripping 5, 10, 15, 20, 25, 30 drops, and to one divided area with an opening width of 102 μm by dripping 6, 12, 18, 24, 30, 36 drops. The area to be coated is an opening with 54 pixels in the short-axis direction and 15 pixels for each dripping number in the long-axis direction, that is, a total of 29160 pixels. Then, the following drying and sintering processes are carried out to fabricate the functional films R3-1, R3-2, R3-3, R3-4, R3-5, R3-6, G3-1, G3-2, G3-3, G3-4, G3-5, G3-6, B3-1, B3-2, B3-3, B3-4, B3-5, B3-6.

[0440] (Fabrication of functional film 51) The functional ink 51 is applied to an opening with 22 pixels in the short-axis direction and 7 pixels in the long-axis direction, that is, a total of 154 pixels on the substrate B2. Then, the following drying and roasting processes are carried out to fabricate the functional film 51. It should be noted that the functional ink 51 is applied to one opening of the substrate B2 by dripping 4 drops.

[0441] (Fabrication of functional film 52) Functional ink 54 is applied to an opening portion of 22 pixels in the short-axis direction and 7 pixels in the long-axis direction, totaling 154 pixels, on substrate B2. Then, by performing the following drying and baking processes, functional film 52 is fabricated. Note that functional ink 54 is applied to one opening portion of substrate B2 by dropping 15 drops.

[0442] (Fabrication of functional film 53) Functional ink 54 is applied to an opening portion of 22 pixels in the short-axis direction and 7 pixels in the long-axis direction, totaling 154 pixels, on substrate B2 on which functional film 51 has been formed as described above. Then, by performing the following drying and baking processes, functional film 53 is fabricated. Note that functional ink 54 is applied to one opening portion of substrate B2 on which functional film 51 has been formed as described above by dropping 15 drops.

[0443] (Fabrication of functional film 54) Functional ink 55 is applied to an opening portion of 45 pixels in the short-axis direction and 32 pixels in the long-axis direction, totaling 1440 pixels, on substrate C2. Then, by performing the following drying and baking processes, functional film 54 is fabricated. Note that functional ink 55 is applied to one opening portion of substrate C2 by dropping 19 drops.

[0444] (Fabrication of functional film 55) Functional ink 52 is applied to an opening portion of 45 pixels in the short-axis direction and 32 pixels in the long-axis direction, totaling 1440 pixels, on substrate C2. Then, by performing the following drying and baking processes, functional film 55 is fabricated. Note that functional ink 52 is applied to one opening portion of substrate C2 by dropping 18 drops.

[0445] (Fabrication of functional film 56) Functional ink 52 is applied to an opening portion of 45 pixels in the short-axis direction and 32 pixels in the long-axis direction, totaling 1440 pixels, on substrate C2 on which functional film 54 has been formed as described above. Then, by performing the following drying and baking processes, functional film 56 is fabricated. Note that functional ink 52 is applied to one opening portion of substrate C2 on which functional film 54 has been formed as described above by dropping 18 drops.

[0446] (Fabrication of functional film 57) Functional ink 55 is applied to an opening portion of 1,440 pixels in total, 45 pixels in the short-axis direction and 32 pixels in the long-axis direction of the substrate C2 having the functional film 55 formed thereon as described above. Then, the functional film 57 is produced by performing the following drying and baking processes. It should be noted that the functional ink 55 is applied to one opening portion of the substrate C2 having the functional film 55 formed thereon as described above in such a manner that 19 drops are dropped in each opening portion.

[0447] <Drying and baking> Each substrate having the functional films 1 to 22 and 51 to 57 formed thereon is placed in a chamber sealed with an openable and closable lid, and is dried under reduced pressure to a pressure of 0.1 Pa or less using a multi-stage pump (manufactured by Ulvac, Inc., VMR-050) combined with a mechanical booster pump and a rotary pump oil.

[0448] Here, for the drying under reduced pressure, it is first reduced from atmospheric pressure to 1 to 10 Pa in 240 seconds, and then made to be 0.1 Pa or less in 180 seconds or more.

[0449] After the drying under reduced pressure, each substrate having the functional films 1 to 22 and 51 to 57 formed thereon is placed on a hot plate heated to 230 °C and baked for 30 minutes, and the following evaluation is performed.

[0450] <Evaluation 1 of functional film> Using a probe contact type step gauge (manufactured by Kosaka Laboratory Ltd., ET-100), the film thickness distribution in the short-axis direction with respect to the opening portion is measured for the obtained functional films 1 to 22. For the measured film thickness distribution, the flatness F is calculated using the following formula (1), and the flatness of each functional film is evaluated. F = M / Ap × 100 (%) (1) In the formula, Ap represents the length of the short axis or the long axis in the divided region, and M represents the length of the distribution portion having a film thickness less than 1.05 and greater than 0.95 when the film thickness distribution measured along the short axis or the long axis in the divided region is divided by the film thickness h at the center of the divided region.

[0451] <Evaluation 2 of functional film> Using a probe contact type step gauge (manufactured by Kosaka Laboratory Ltd., ET-100), the film thickness distributions in the short-axis and long-axis directions with respect to the opening portion are measured for the obtained functional films 51 to 57. For the measured film thickness distribution, the flatness F is calculated using the following formula (1), and the flatness of each functional film is evaluated. F = M / Ap × 100 (%) (1) Here, Ap represents the length of the minor axis or major axis of the opening part of the partition dyke, and M represents the length (area) of the functional film having a film thickness less than 1.05 and greater than 0.95 when the film thickness distribution obtained by measuring the minor axis or major axis part of the opening part using a non-contact measuring instrument such as a probe contact profilometer or a white interferometer is divided by the film thickness h of the central part.

[0452] <Fabrication of Organic Electroluminescent Element> (Film Formation of Hole Transport Layer) Place the substrate coated with the functional films 15 and 53 in a vacuum evaporation apparatus, and evacuate the inside of the apparatus to 2×10 -4 Pa or less. Then, using the vacuum evaporation method and at a rate of , evaporate the compound represented by the following formula (HT-1) onto the functional films 15 and 53 to form a light-emitting layer with a film thickness of 20 nm.

[0453] [Chemical Formula 28]

[0454] (Film Formation of Light-Emitting Layer) Next, using the vacuum evaporation method at a rate of, evaporate the compound represented by the following formula (EM-1) onto the hole transport layer to form a light-emitting layer with a film thickness of 50 nm.

[0455] [Chemical Formula 29]

[0456] (Film Formation of Electron Transport Layer) Next, using the vacuum evaporation method and at a total rate of , evaporate the compound represented by the following formula (HB-1) and lithium 8-hydroxyquinoline onto the light-emitting layer at a film formation rate ratio of 4:3 to form a hole blocking layer with a film thickness of 10 nm.

[0457] [Chemical Formula 30]

[0458] (Film Formation of Cathode) Next, bring the striped shadow mask, which is a mask for cathode evaporation, into close contact with the substrate in a manner orthogonal to the ITO stripes of the anode, and place it in another vacuum evaporation apparatus. Moreover, it is known that by heating magnesium and silver and co-evaporating them at a rate of 1:9, a Mg / Ag layer with a film thickness of 25 nm is formed, thereby forming the cathode.

[0459] (Film Formation of Cover Layer) Next, using the vacuum evaporation method and at a rate of The compound represented by the above formula (HT-1) was vapor-deposited on the cathode at a speed to form a covering layer with a film thickness of 70 nm. Then, it was sealed with an ultraviolet curable resin in a nitrogen atmosphere to obtain an organic electroluminescent element.

[0460] <Observation of Organic Electroluminescent Element> A voltage of 7.4 volts was applied to the fabricated organic electroluminescent element using a power supply device (manufactured by ADVANTEST CORPORATION, R6144). The luminescence image was taken with a microscope (manufactured by Nikon Corporation, LV100) at a magnification of 20 to observe the luminescence state within the divided area. The tristimulus values XYZ were calculated using the following formula based on the values of the RGB colorimetric system determined by the sRGB method for the pixels stored in the captured image, and the distribution of the chromaticity coordinates (CIEx, CIEy) within the divided area was calculated according to the method described in JIS Z8701. X = 0.4124R + 0.3576G + 0.1805B Y = 0.2126R + 0.7152G + 0.0722B Z = 0.0193R + 0.1192G + 0.9505B

[0461] <Tests and Considerations> (Reference Example 1-1) Figure 2 The solid line in... indicates the film thickness distribution (calculated) of the functional film obtained by numerically calculating and adding the film thickness distribution (measured) of the functional film 7 indicated by the dotted line and the film thickness distribution (measured) of the functional film 8 indicated by the dashed line, with the functional film 7 as the functional layer 1 and the functional film 8 as the functional layer 2 for simulation reproduction.

[0462] (Reference Example 1-2) Figure 3 The solid line in... indicates the film thickness distribution (calculated) obtained by numerically calculating and adding the film thickness distribution (measured) of the functional film 7 and the film thickness distribution (measured) of the functional film 8, and the dashed line indicates the film thickness distribution (measured) of the functional film 11. As... Figure 3 shown, the shape of the film thickness distribution (calculated) of the functional film simulated and reproduced by numerical calculation processing is basically the same as the film thickness distribution (measured) of the functional film actually laminated and formed. Thus, it can be known that the film thickness distribution of the functional film formed by laminating a convex-shaped functional film and a concave-shaped functional film in the order from near to far from the substrate can be reproduced by numerically calculating and adding the film thickness distributions of the respective single films of the convex-shaped functional film and the concave-shaped functional film.

[0463] (Reference Example 1-3) Figure 4The solid line represents the film thickness distribution (calculated) obtained by adding the film thickness distribution (measured) of the functional film 7 and the film thickness distribution (measured) of the functional film 8 through numerical calculation processing, and the dashed line represents the film thickness distribution (measured) of the functional film 12. As Figure 4 shown, the shape of the film thickness distribution (calculated) of the functional film simulated and reproduced through numerical calculation processing is basically the same as the shape of the film thickness distribution (measured) of the functional film actually laminated and formed. Thus, it can be known that the film thickness distribution of the functional film formed by laminating the concave-shaped functional film and the convex-shaped functional film in the order from near to far from the substrate can reproduce the film thickness distributions of the respective single films of the concave-shaped functional film and the convex-shaped functional film by adding them through numerical calculation processing.

[0464] (Example 1) Figure 5 The solid line represents the film thickness distribution (calculated) obtained by adding the film thickness distribution (measured) of the functional film 1 shown by the dotted line and the film thickness distribution (measured) of the functional film 2 shown by the short dashed line through numerical calculation processing, and the flatness F is 77%. The flatness F of the single film of the functional film 1 is 30%, and the flatness F of the single film of the functional film 2 is 26%. It can be seen that the flatness is improved by laminating the functional film 1 and the functional film 2.

[0465] (Example 2) Figure 6 The solid line represents the film thickness distribution (calculated) obtained by adding the film thickness distribution (measured) of the functional film 3 shown by the dotted line and the film thickness distribution (measured) of the functional film 4 shown by the short dashed line through numerical calculation processing, and the flatness F is 75%. The flatness F of the single film of the functional film 3 is 34%, and the flatness F of the single film of the functional film 4 is 34%. It can be seen that the flatness is improved by laminating the functional film 3 and the functional film 4.

[0466] (Example 3) Figure 7 The solid line represents the film thickness distribution (calculated) obtained by adding the film thickness distribution (measured) of the functional film 5 shown by the dotted line and the film thickness distribution (measured) of the functional film 6 shown by the short dashed line through numerical calculation processing, and the flatness F is 76%. The flatness F of the single film of the functional film 5 is 40%, and the flatness F of the single film of the functional film 6 is 49%. It can be seen that the flatness is improved by laminating the functional film 5 and the functional film 6.

[0467] (Example 4) Figure 8The solid line represents the film thickness distribution (calculated) obtained by numerically calculating and adding the film thickness distribution (measured) of the functional film 7 shown by the dotted line and the film thickness distribution (measured) of the functional film 8 shown by the dashed line. The flatness F is 95%. The flatness F of the single film of the functional film 7 is 78%, and the flatness F of the single film of the functional film 8 is 80%. It can be seen that the flatness is improved by laminating the functional film 7 and the functional film 8.

[0468] (Example 5) Figure 9 The solid line represents the film thickness distribution (calculated) obtained by numerically calculating and adding the film thickness distribution (measured) of the functional film 9 shown by the dotted line and the film thickness distribution (measured) of the functional film 10 shown by the dashed line. The flatness F is 87%. The flatness F of the single film of the functional film 9 is 42%, and the flatness F of the single film of the functional film 10 is 67%. It can be seen that the flatness is improved by laminating the functional film 9 and the functional film 10.

[0469] (Reference Example 2) Figure 10 Represents the film thickness distribution (measured) of the functional film 13 shown by the dashed line, the film thickness distribution (measured) of the functional film 14 shown by the dotted line, and the film thickness distribution (measured) of the functional film 15 shown by the solid line. The flatness F of each functional film is 59%, 66%, and 86%. In addition, for the functional film 15, an organic electroluminescent element manufactured by the above method was observed. Figure 11 and Figure 12 Represents the position where the film thickness distribution is measured and the distribution of the chromaticity coordinates CIEx and CIEy on the short axis of the organic electroluminescent element photographed at the same location using a microscope. Here, the area surrounded by the dashed line represents the opening. It can be seen that although the flatness F of each of the functional film 14 and the functional film 15 is low, by improving the flatness in each laminated film (functional film 15), the cavity length becomes uniform, so the chromaticity of the opening is uniformly distributed, and uniform light emission can be obtained within the divided region by this method.

[0470] (Reference Example 3-1) Figure 13 The solid line represents the film thickness distribution (calculated) of the functional film obtained by numerically calculating and adding the film thickness distribution (measured) of the functional film 16 shown by the dotted line and the film thickness distribution (measured) of the functional film 17 shown by the dashed line, and by simulating and reproducing with the functional film 16 as the functional layer 1 and the functional film 17 as the functional layer 2.

[0471] (Reference Example 3-2) Figure 14The solid line represents the film thickness distribution (calculated) obtained by numerically calculating and adding the film thickness distribution (measured) of the functional film 16 and the film thickness distribution (measured) of the functional film 17. The dashed line represents the film thickness distribution (measured) of the functional film 18. As Figure 14 shown, the shape of the film thickness distribution (calculated) of the functional film simulated and reproduced by numerical calculation is basically the same as the shape of the film thickness distribution (measured) of the functional film actually laminated and formed. Thus, it can be known that the film thickness distribution of the functional film formed by laminating the convex-shaped functional film and the concave-shaped functional film in order from near to far from the substrate can reproduce the film thickness distribution of each single film of the convex-shaped functional film and the concave-shaped functional film by numerically calculating and adding them.

[0472] (Reference Example 3-3) Figure 15 The solid line represents the film thickness distribution (calculated) of the functional film obtained by numerically calculating and adding the film thickness distribution (measured) of the functional film 19 indicated by the dotted line and the film thickness distribution (measured) of the functional film 17 indicated by the dashed line, and simulating and reproducing with the functional film 19 as the functional layer 1 and the functional film 17 as the functional layer 2.

[0473] (Reference Example 3-4) Figure 16 The solid line represents the film thickness distribution (calculated) obtained by numerically calculating and adding the film thickness distribution (measured) of the functional film 19 and the film thickness distribution (measured) of the functional film 17. The dashed line represents the film thickness distribution (measured) of the functional film 20. As Figure 16 shown, the shape of the film thickness distribution (calculated) of the functional film simulated and reproduced by numerical calculation is basically the same as the shape of the film thickness distribution (measured) of the functional film actually laminated and formed. Thus, it can be known that the film thickness distribution of the functional film formed by laminating the convex-shaped functional film and the concave-shaped functional film in order from near to far from the substrate can reproduce the film thickness distribution of each single film of the convex-shaped functional film and the concave-shaped functional film by numerically calculating and adding them.

[0474] (Reference Example 3-5) Figure 17 The solid line represents the film thickness distribution (calculated) of the functional film obtained by numerically calculating and adding the film thickness distribution (measured) of the functional film 21 indicated by the dotted line and the film thickness distribution (measured) of the functional film 17 indicated by the dashed line, and simulating and reproducing with the functional film 21 as the functional layer 1 and the functional film 17 as the functional layer 2.

[0475] (Reference Example 3-6) Figure 18The solid line represents the film thickness distribution (calculated) obtained by numerically calculating and adding the film thickness distribution (measured) of the functional film 21 and the film thickness distribution (measured) of the functional film 17. The dashed line represents the film thickness distribution (measured) of the functional film 22. As Figure 18 shown, the shape of the film thickness distribution (calculated) of the functional film simulated and reproduced by numerical calculation is basically the same as the film thickness distribution (measured) of the functional film actually laminated and formed. Thus, it can be known that the film thickness distribution of the functional film formed by laminating the convex-shaped functional film and the concave-shaped functional film in the order from near to far from the substrate can reproduce the film thickness distribution of each single film of the convex-shaped functional film and the concave-shaped functional film by numerically calculating and adding them.

[0476] (Reference Example 51-1) Figure 19 The solid line represents the film thickness distribution (calculated) of the functional film obtained by numerically calculating and adding the film thickness distribution (measured) of the functional film 54 indicated by the dotted line and the film thickness distribution (measured) of the functional film 55 indicated by the dash line. The functional film 54 is used as the functional layer 1, and the functional film 55 is used as the functional layer 2 for simulation and reproduction.

[0477] (Reference Example 51-2) Figure 20 The solid line represents the film thickness distribution (calculated) obtained by numerically calculating and adding the film thickness distribution (measured) of the functional film 54 and the film thickness distribution (measured) of the functional film 55. The dashed line represents the film thickness distribution (measured) of the functional film 56. As Figure 20 shown, the shape of the film thickness distribution (calculated) of the functional film simulated and reproduced by numerical calculation is basically the same as the film thickness distribution (measured) of the functional film actually laminated and formed. Thus, it can be known that the film thickness distribution of the functional film formed by laminating the convex-shaped functional film and the concave-shaped functional film in the order from near to far from the substrate can reproduce the film thickness distribution of each single film of the convex-shaped functional film and the concave-shaped functional film by numerically calculating and adding them.

[0478] (Reference Example 51-3) Figure 21 The solid line represents the film thickness distribution (calculated) obtained by numerically calculating and adding the film thickness distribution (measured) of the functional film 54 and the film thickness distribution (measured) of the functional film 55. The dashed line represents the film thickness distribution (measured) of the functional film 57. As Figure 21As shown, the shape of the film thickness distribution (calculated) of the functional film simulated and reproduced by numerical calculation processing is basically the same as that of the functional film actually laminated and formed (measured). Thus, it can be known that the film thickness distribution of the functional film formed by laminating the concave-shaped functional film and the convex-shaped functional film in the order from near to far from the substrate can reproduce the film thickness distributions of the respective single films of the concave-shaped functional film and the convex-shaped functional film by adding them through numerical calculation processing.

[0479] (Reference Example 52) Figure 22 The solid line in the figure indicates the film thickness distribution (measured) of the functional film 51 shown by the short dash line, the film thickness distribution (measured) of the functional film 52 shown by the dotted line, and the film thickness distribution of the functional film 53 shown by the solid line. The flatness F of each functional film is 59%, 66%, and 86%. In addition, for the functional film 53, an organic electroluminescent element fabricated by the above method was observed. Figure 23 and Figure 24 It shows the positions for measuring the film thickness distribution and the distributions of the chromaticity coordinates CIEx and CIEy on the short axis of the organic electroluminescent element photographed at the same location using a microscope. Here, the region surrounded by the short dash line represents the opening. It can be seen that although the flatness F of each of the functional film 51 and the functional film 52 is low, by improving the flatness in each laminated film (functional film 53), the cavity length becomes uniform, so the chromaticity of the opening is uniformly distributed, and uniform light emission can be obtained within the divided region by this method.

[0480] (Reference Example 53-1) Figure 25 It shows the film thickness distributions of the functional films R1-1, R1-2, R1-3, R1-4, R1-5, and R1-6. Figure 26 It shows the film thickness distributions of the functional films G1-1, G1-2, G1-3, G1-4, G1-5, and G1-6. Figure 27 It shows the film thickness distributions of the functional films B1-1, B1-2, B1-3, B1-4, B1-5, and B1-6. The flatness F of each functional film was calculated using the formula (1) described in "<Evaluation 2 of Functional Films>", and evaluated as ○ when it was 85% or more and as × when it was less than 85%. The cases where the average film thickness of the central part was thicker than that of the partition side part were regarded as convex shapes, and the cases where the average film thickness of the central part was thinner than that of the partition side part were regarded as concave shapes, and the results are summarized in Tables 1 to 3. It can be seen that even with the same film thickness, if the pixel size is different, the flatness is different. Similarly, even with the same pixel size, if the film thickness is different, the flatness is also different. In addition, when manufacturing an organic electroluminescent element by laminating only flat films by the wet coating method, the functional films that can be used are only R1-1, G1-1, G1-6, B1-2, and B1-6.

[0481] [Table 1] Table 1 Functional film Film thickness (nm) Flatness (%) Judgment Shape R1-1 30 87 〇 Convex R1-2 49 65 × Convex R1-3 72 58 × Convex R1-4 94 63 × Convex R1-5 118 66 × Convex R1-6 141 79 × Convex

[0482] [Table 2] Table 2 Functional film Film thickness (nm) Flatness (%) Judgment Shape G1-1 26 87 〇 Convex G1-2 42 81 × Convex G1-3 60 75 × Convex G1-4 81 75 × Convex G1-5 100 81 × Convex G1-6 121 90 〇 Concave

[0483] [Table 3] Table 3 Functional film Film thickness (nm) Flatness (%) Judgment Shape B1-1 25 22 × Convex B1-2 39 86 〇 Convex B1-3 54 83 × Convex B1-4 72 81 × Convex B1-5 91 84 × Convex B1-6 109 96 〇 Concave

[0484] (Reference Example 53-2) Figure 28 Shows the film thickness distribution of the functional films R2-1, R2-2, R2-3, R2-4, and R2-5. Figure 29 Shows the film thickness distribution of the functional films G2-1, G2-2, G2-3, G2-4, G2-5, and G2-6. Figure 30 Shows the film thickness distribution of the functional films B2-1, B2-2, B2-3, B2-4, B2-5, and B2-6. The flatness F of each functional film was calculated using the formula (1) described in "<Evaluation 2 of Functional Films>", and evaluated as ○ when it was 85% or more and as × when it was less than 85%. The cases where the average film thickness of the central part was thicker than that of the partition side part were regarded as convex shapes, and the cases where the average film thickness of the central part was thinner than that of the partition side part were regarded as concave shapes, and the results are summarized in Tables 4 to 6. It can be seen that even with the same film thickness, if the pixel size is different, the flatness is different. Similarly, even with the same pixel size, if the film thickness is different, the flatness is also different. In addition, when manufacturing an organic electroluminescent element by laminating only flat films by the wet coating method, the functional films that can be used are only R2-4, G2-4, G2-5, and B2-4.

[0485] [Table 4] Table 4 Functional film Film thickness (nm) Flatness (%) Judgment Shape R2-1 30 39 × Convex R2-2 49 28 × Convex R2-3 73 46 × Convex R2-4 98 90 〇 Concave R2-5 121 81 × Concave

[0486] [Table 5] Table 5 Functional film Film thickness (nm) Flatness (%) Judgment Shape G2-1 25 43 × Convex G2-2 44 37 × Convex G2-3 65 63 × Convex G2-4 86 93 〇 Convex G2-5 104 88 〇 Concave G2-6 127 74 × Concave

[0487] [Table 6] Table 6 Functional film Film thickness (nm) Flatness (%) Judgment Shape B2-1 22 54 × Convex B2-2 40 54 × Convex B2-3 62 78 × Convex B2-4 79 87 〇 Concave B2-5 96 70 × Concave B2-6 116 66 × Concave

[0488] (Reference Example 53-3) Figure 31 Shows the film thickness distribution of the functional films R3-1, R3-2, R3-3, R3-4, R3-5, and R3-6. Figure 32 Shows the film thickness distribution of the functional films G3-1, G3-2, G3-3, G3-4, G3-5, and G3-6. Figure 33 Shows the film thickness distribution of the functional films B3-1, B3-2, B3-3, B3-4, B3-5, and B3-6. Using the formula (1) described in <Evaluation 2 of Functional Films>, the flatness F of each functional film was calculated. Those with 85% or more were judged as 〇, and those below 85% were judged as × for evaluation. The cases where the average film thickness of the central part was thicker than the average film thickness of the partition wall side part were regarded as convex shapes, and the cases where the average film thickness of the central part was thinner than the average film thickness of the partition wall side part were regarded as concave shapes and summarized in Tables 7 to 9. In addition, in the case of manufacturing an organic electroluminescent element by laminating only flat films by the wet coating method, there is no functional film that can be used.

[0489] [Table 7] Table 7 Functional film Film thickness (nm) Flatness (%) Judgment Shape R3-1 25 26 × Concave R3-2 45 28 × Convex R3-3 67 35 × Concave R3-4 93 63 × Concave R3-5 124 72 × Concave R3-6 152 67 × Concave

[0490] [Table 8] Table 8 Functional film Film thickness (nm) Flatness (%) Judgment Shape G3-1 27 41 × Concave G3-2 46 34 × Convex G3-3 66 39 × Convex G3-4 86 47 × Concave G3-5 112 60 × Concave G3-6 133 73 × Concave

[0491] [Table 9] Table 9 Functional film Film thickness (nm) Flatness (%) Judgment Shape B3-1 24 50 × Convex B3-2 43 46 × Convex B3-3 64 52 × Convex B3-4 84 60 × Convex B3-5 103 72 × Concave B3-6 122 83 × Concave

[0492] (Reference Example 54-1) In the case of laminating functional films obtained using functional ink 51 and functional ink 52 to obtain a laminated film, films are formed by laminating combinations that have a good flatness F level in the conventional method of laminating flat functional films and that have a flatness F of 85% or more in the present case. Table 10 shows combinations with a good flatness F level. It can be seen that there is 1 group of laminated film 1 when the division has an opening width of 49 μm, 4 groups of laminated films 2 to 5 when the division has an opening width of 75 μm, and 2 groups of laminated films 6 to 7 when the division has an opening width of 102 μm. Here, according to Reference Examples 51-2 and 51-3, both the functional layer 1 and the functional layer 2 can be the lower layer and the upper layer. Since the number of flat laminated films for each opening width has been determined, the number of combinations in which all three of these opening widths result in flat laminated films is 1×4×2 = 8 groups, and the selectable range is very limited.

[0493] [Table 10] Table 10

[0494] (Reference Example 54-2) In the case of laminating functional layers obtained using functional ink 51 and functional ink 53 to obtain a functional film, films are formed by laminating combinations that have a good flatness F level in the conventional method of laminating flat functional films and that have a flatness F of 85% or more in the present case. However, since the flatness F of all the functional films formed using functional ink 53 is less than 85%, a laminated functional film cannot be obtained by the existing method.

[0495] (Example 51) The respective functional films R1-1, R1-2, R1-3, R1-4, R1-5, R1-6 and the respective functional films R2-1, R2-2, R2-3, R2-4, R2-5 are added through numerical calculation processing to simulate the production of a laminated film. Among the functional films constituting the laminated film, at least one has a flatness F of less than 85%. Those with a flatness F of the laminated film of 85% or more are shown in Table 11. Those who perform the same operation on the respective functional films G1-1, G1-2, G1-3, G1-4, G1-5, G1-6 and the respective functional films G2-1, G2-2, G2-3, G2-4, G2-5, G2-6 are summarized in Table 12, and those who perform the same operation on the respective functional films B1-1, B1-2, B1-3, B1-4, B1-5, B1-6 and the respective functional films B2-1, B2-2, B2-3, B2-4, B2-5, B2-6 are summarized in Table 13.

[0496] According to Table 11, there are 4 groups of laminated films 8 to 11 that are flat in the division with an opening width of 49 μm. According to Table 12, among the laminating films that are flat in the division with an opening width of 75 μm, there are 10 groups of laminating films 12 to 21, and among them, there is 1 group of laminating film 13 where both Layer 1 and Layer 2 are convex-shaped. According to Table 13, among the laminating films that are flat in the division with an opening width of 102 μm, there are 12 groups of laminating films 22 to 33, and among them, there is 1 group of laminating film 31 where both Layer 1 and Layer 2 are concave-shaped.

[0497] Therefore, among the laminating films in the division with an opening width of 49 μm, there are 5 groups of laminating films 1, 8 to 11 with a flatness F of 85% or more; in the division with an opening width of 75 μm, there are 14 groups of laminating films 2 to 5, 12 to 21; and in the division with an opening width of 102 μm, there are 14 groups of laminating films 6 to 7, 22 to 33. Thus, the number of combinations of all the laminating films that are flat for these three opening widths is 5 × 14 × 14 = 980 groups. In addition, among them, the laminating films composed of combinations of functional films with a flatness F of 85% or more, the laminating films composed of combinations of functional films with convex shapes and convex shapes, and the laminating films composed of combinations of functional films with concave shapes and concave shapes are 1 group of laminating film 1 in the division with an opening width of 49 μm, 5 groups of laminating films 2 to 5, 13 in the division with an opening width of 75 μm, and 3 groups of laminating films 6 to 7, 31 in the division with an opening width of 102 μm. Combining these laminating films, the number of combinations of all the laminating films that are flat for the three opening widths is 1 × 5 × 3 = 15 groups.

[0498] Therefore, the number of combinations that can be taken by using the present invention is 980 - 15 = 965 groups. In the existing method shown in Reference Example 4-1 where only films with a flatness F of 85% or more are formed, it is 8 groups. Thus, it can be seen that the number of combinations that can be made according to the present invention increases by about 121 times. It can be seen that with such functional inks showing the same functionality, the selection range of the film thickness structure can be greatly expanded, and the productivity can be improved.

[0499] [Table 11] Table 11

[0500] [Table 12] Table 12

[0501] [Table 13] Table 13

[0502] (Example 52) The functional films R1-1, R1-2, R1-3, R1-4, R1-5, R1-6 and the functional films R3-1, R3-2, R3-3, R3-4, R3-5 are added by numerical calculation processing to simulate and fabricate a laminated film. Among the functional films constituting the laminated film, the flatness F of at least one is less than 85%. Those with a flatness F of the laminated film of 85% or more are shown in Table 14. Those who perform the same operation on the functional films G1-1, G1-2, G1-3, G1-4, G1-5, G1-6 and the functional films G3-1, G3-2, G3-3, G3-4, G3-5, G3-6 are summarized in Table 15, and those who perform the same operation on the functional films B1-1, B1-2, B1-3, B1-4, B1-5, B1-6 and the functional films B3-1, B3-2, B3-3, B3-4, B3-5, B3-6 are summarized in Table 16.

[0503] According to Table 14, the laminated films that are flat in the division with an opening width of 49 μm are 4 groups of laminated films 34 to 37. According to Table 15, the laminated films that are flat in the division with an opening width of 75 μm are 8 groups of laminated films 38 to 45, and among them, the 2 groups of laminated films 40 and 45 are those in which both layer 1 and layer 2 are concave shapes. According to Table 16, the laminated films that are flat in the division with an opening width of 102 μm are 9 groups of laminated films 46 to 54, and among them, 1 group of laminated film 46 is those in which both layer 1 and layer 2 are convex shapes, and 2 groups of laminated films 49 and 54 are those in which both are concave shapes. Therefore, it can be known that the number of combinations in which all the laminated films of the 3 opening widths are flat is 4×8×9 = 288 groups. The choice range of the film thickness structure can be greatly expanded by using the functional ink showing the same functionality, and the productivity can be improved. In addition, among them, the laminated films composed of combinations of functional films with a flatness F of 85% or more, the laminated films composed of combinations of functional films with convex shapes and convex shapes, and the laminated films composed of combinations of functional films with concave shapes and concave shapes are 0 groups in the division with an opening width of 49 μm, 2 groups of laminated films 40 and 45 in the division with an opening width of 75 μm, and 3 groups of laminated films 46, 49, and 54 in the division with an opening width of 102 μm. Combining these laminated films, the number of combinations in which all the laminated films of the 3 opening widths are flat is 0×2×3 = 0 groups.

[0504] Therefore, the number of combinations that can be taken by using the present invention is 288 - 0 = 288 groups. It can be seen that this is a significant increase compared to 0 groups in the existing method shown in Reference Example 54-2.

[0505] In addition, in order to explore the film thickness structure with a flatness of 85% or more during lamination, the existing method needs to fabricate and explore 36 groups of laminated films, but by using the present invention, 12 groups of films can be fabricated and the film thickness design can be simplified.

[0506] [Table 14] Table 14

[0507] [Table 15] Table 15

[0508] [Table 16] Table 16

[0509] According to this result, even for a functional layer with a non-flat shape, the total film thickness can be made uniform by combination, and uniform light emission can be obtained.

[0510] Although the present invention has been described in detail in a specific manner, it is obvious to those skilled in the art that various changes can be made without departing from the intention and scope of the present invention.

[0511] As described above, various embodiments have been described, but needless to say, the present invention is not limited to the examples. It is obvious to those skilled in the art that various modification examples or correction examples can be conceived within the scope described in the claims, and of course, these also belong to the technical scope of the present invention. In addition, within the scope not departing from the gist of the invention, the constituent elements in the above-described embodiments can be arbitrarily combined.

[0512] It should be noted that this application is based on Japanese Patent Applications filed on November 2, 2022 (Japanese Patent Application No. 2022-176734, Japanese Patent Application No. 2022-176735, Japanese Patent Application No. 2022-176736), and their contents are incorporated herein by reference. Industrial Applicability

[0513] The flatness of the functional film of the organic electroluminescent element of the present invention or the organic electroluminescent element contained in the organic EL display panel of the present invention is high and the optical characteristics are excellent. Therefore, it can be applied to organic electroluminescent devices having various emission colors such as organic EL display devices and organic EL lighting. In addition, according to the film thickness structure design method of the organic electroluminescent element of the present invention, when forming the functional film contained in the organic electroluminescent element or the plurality of organic electroluminescent elements constituting the organic EL display panel by wet film formation, even if various conditions such as the film thickness of the organic film, the partition material, the size of the pixel, the reduced-pressure drying process, and the ink composition change, it is possible to simply design the film thickness structure of an organic electroluminescent element or an organic EL display panel having...

Claims

1. An organic electroluminescent element, which is an organic electroluminescent element having a functional film in which at least a functional layer 1 and a functional layer 2 are laminated, wherein, the organic electroluminescent element is disposed in a divided region partitioned by a partition wall, wherein, the functional ink for forming the functional layer 1 is filled into the divided region in an amount required for forming the functional layer 1, and then a film is formed by drying under reduced pressure. When the film is set as the functional film 1, the average film thickness of the central portion in the divided region of the functional film 1 is thicker than the average film thickness of the partition wall side portion in the divided region, the functional ink for forming the functional layer 2 is filled into the divided region in an amount required for forming the functional layer 2, and then a film is formed by drying under reduced pressure. When the film is set as the functional film 2, the average film thickness of the partition wall side portion in the divided region of the functional film 2 is thicker than the average film thickness of the central portion in the divided region, the central portion means the inside of a region bounded by a closed curve determined by the locus of points at 60% of the position from the center of gravity to the partition wall when scanning the entire outer periphery of the divided region with a straight line passing through the center of gravity of the divided region, the partition wall side portion means the outside of the region bounded by the closed curve within the divided region, further, the closed curve may or may not include a straight line portion and a corner portion, the flatness F of the film laminated with the functional layer 1 and the functional layer 2 exhibits a value greater than either the flatness F of the functional film 1 or the flatness F of the functional film 2, wherein, the flatness F is represented by the following formula: F = M / Ap × 100 (%) In the formula, Ap represents the length of the minor axis or the major axis in the divided region, and M represents the length of the distribution portion having a film thickness less than 1.05 and greater than 0.95 when the film thickness distribution measured along the minor axis or the major axis in the divided region is divided by the film thickness h at the center of the divided region.

2. The organic electroluminescent element according to claim 1, wherein, the functional film 1 is a film in which the thickest portion of the film thickness is located in the central portion of the divided region, the functional film 2 is a film in which the thickest portion of the film thickness is located in a region other than the central portion of the divided region.

3. The organic electroluminescent element according to claim 1, wherein The average film thickness of the functional film 1 is thinner than the average film thickness of the functional film 2.

4. The organic electroluminescent element according to claim 1, wherein, The functional layer 1 and the functional layer 2 are a hole injection layer or a hole transport layer.

5. The organic electroluminescent element according to claim 1, wherein, The functional layer 1 and the functional layer 2 contain a polymer compound.

6. A method for manufacturing the organic electroluminescent element according to any one of claims 1 to 5, the method including the following process group (ii) after the following process group (i) or including the following process group (i) after the following process group (ii), wherein, Process group (i) sequentially includes: a process of printing the functional ink for forming the functional layer 1 into the divided region by an inkjet method; a process of drying the printed divided region under reduced pressure in a vacuum chamber; a process of baking the dried divided region; The process group (ii) sequentially includes: a process of printing a functional ink for forming the functional layer 2 onto the divided area by an inkjet method; a process of subjecting the printed divided area to reduced-pressure drying in a vacuum chamber; and a process of baking the dried divided area.

7. The method according to claim 6, wherein at least one of the functional ink for forming the functional layer 1 and the functional ink for forming the functional layer 2 contains two or more organic solvents. In the process group that uses the functional ink containing two or more organic solvents among the process groups (i) and (ii), in the process of subjecting the divided area to reduced-pressure drying in a vacuum chamber, the time when the pressure reaches lower than the vapor pressure of the organic solvent having the lowest vapor pressure among the two or more organic solvents is 60 seconds or more and 1800 seconds or less after the start of reduced-pressure drying.

8. An organic EL display panel, which is an organic EL display panel having a plurality of divided areas partitioned by partition walls and having an organic electroluminescent element formed in the divided area, wherein the plurality of divided areas at least have a first divided area and a second divided area. The opening areas of the organic electroluminescent elements in the first divided area and the second divided area are different from each other. The first divided area and the second divided area each independently have a functional film in which at least the functional layer 1 and the functional layer 2 are laminated. The functional material for forming the functional layer 1 in the first divided area is the same as the functional material for forming the functional layer 1 in the second divided area. The functional material for forming the functional layer 2 in the first divided area is the same as the functional material for forming the functional layer 2 in the second divided area. Any one of the first divided area and the second divided area at least satisfies the following condition: Condition: When the functional ink for forming the functional layer 1 is filled into the divided area in an amount required for forming the functional layer 1, and then a film is formed by reduced-pressure drying and the film is set as the functional film 1, the average film thickness of the functional film 1 at the central portion of the divided area is thicker than the average film thickness at the partition wall side portion. When the functional ink for forming the functional layer 2 is filled into the divided area in an amount required for forming the functional layer 2, and then a film is formed by reduced-pressure drying and the film is set as the functional film 2, the average film thickness of the functional film 2 at the central portion of the divided area is thinner than the average film thickness at the partition wall side portion. Here, the central portion refers to the inside of the area bounded by a closed curve determined by the locus of points at 60% of the position from the center of gravity to the partition wall when scanning the entire outer periphery of the divided area with a straight line passing through the center of gravity of the divided area; in addition, the partition wall side portion refers to the outside of the area bounded by the closed curve within the divided area; the closed curve may or may not include a straight portion and a corner portion.

9. The organic EL display panel according to claim 8, wherein, The flatness F of the film laminated with the functional layer 1 and the functional layer 2 exhibits a value greater than any one of the flatness F of the functional film 1 and the flatness F of the functional film 2. Among them, the flatness F is expressed by the following formula: F = M / Ap × 100 (%) In the formula, Ap represents the length of the minor axis or the major axis in the divided region, and M represents the length of the distribution portion having a film thickness less than 1.05 and greater than 0.95 when the film thickness distribution measured along the minor axis or the major axis in the divided region is divided by the film thickness h at the center of the divided region.

10. The organic EL display panel according to claim 8, wherein the functional film 1 is a film in which the thickest part of the film thickness is located at the central part of the divided region, the functional film 2 is a film in which the thickest part of the film thickness is located in a region other than the central part of the divided region.

11. The organic EL display panel according to claim 8, wherein, The average film thickness of the functional film 1 is thinner than the average film thickness of the functional film 2.

12. The organic EL display panel according to claim 8, wherein, The functional layer 1 and the functional layer 2 are a hole injection layer or a hole transport layer.

13. The organic EL display panel according to claim 8, wherein, The functional layer 1 and the functional layer 2 contain a polymer compound.

14. According to the method for manufacturing the organic EL display panel according to any one of claims 8 to 13, the method includes the following process group (ii) after the following process group (i) or includes the following process group (i) after the following process group (ii), wherein the process group (i) sequentially includes: a process of printing the functional ink for forming the functional layer 1 into the divided region by an inkjet method; a process of subjecting the printed divided region to reduced-pressure drying in a vacuum chamber; a process of baking the dried divided region; the process group (ii) sequentially includes: a process of printing the functional ink for forming the functional layer 2 into the divided region by an inkjet method; a process of subjecting the printed divided region to reduced-pressure drying in a vacuum chamber; a process of baking the dried divided region.

15. According to the method of claim 14, at least one of the functional ink for forming the functional layer 1 and the functional ink for forming the functional layer 2 contains two or more organic solvents, in the process group (i) and the process group (ii), in the process of subjecting the divided region to reduced-pressure drying in the process group using the functional ink containing two or more organic solvents, the time when the pressure reaches lower than the vapor pressure of the organic solvent having the lowest vapor pressure among the two or more organic solvents is 60 seconds or more and 1800 seconds or less after the start of reduced-pressure drying.

16. A design method for the film thickness structure of an organic electroluminescent element, the organic electroluminescent element being disposed in a divided region partitioned by partition walls and having a film thickness structure of an organic electroluminescent element having at least a functional film in which a functional layer 1 and a functional layer 2 are stacked, wherein when stacking the functional film 1 and the functional film 2, the film thicknesses of their respective films are set to the following combination: the flatness F of the film obtained by numerically calculating and adding the film thickness distribution of the functional film 1 and the film thickness distribution of the functional film 2 is 75% or more, the functional film 1 is a film formed by filling the functional ink for forming the functional layer 1 into the divided region in an amount required for forming the functional layer 1 and then performing reduced-pressure drying; The functional film 2 is a film formed by filling a functional ink for forming the functional layer 2 into the divided region in an amount required for forming the functional layer 2, and then drying under reduced pressure. Among them, the flatness F is represented by the following formula: F = M / Ap × 100(%) In the formula, Ap represents the length of the minor axis or major axis in the divided region, and M represents the length of the distribution part having a film thickness less than 1.05 and greater than 0.95 when the film thickness distribution measured along the minor axis or major axis in the divided region is divided by the film thickness h at the center of the divided region.

17. The method for designing the film thickness structure of the organic electroluminescent element according to claim 16, wherein The flatness F of the film in which the functional layer 1 and the functional layer 2 are laminated presents a value greater than any one of the flatness F of the functional film 1 and the flatness F of the functional film 2.

18. The method for designing the film thickness structure of the organic electroluminescent element according to claim 16, wherein The functional film 1 is a film in which the thickest part of the film thickness is located at the central part of the divided region, The functional film 2 is a film in which the thickest part of the film thickness is located in a region other than the central part of the divided region.

19. The design method of the film thickness structure of the organic electroluminescent element according to claim 16, wherein, The average film thickness of the functional film 1 is thinner than the average film thickness of the functional film 2.

20. The design method of the film thickness structure of the organic electroluminescent element according to claim 16, wherein, The functional layer 1 and the functional layer 2 are a hole injection layer or a hole transport layer.

21. The design method of the film thickness structure of the organic electroluminescent element according to claim 16, wherein, The functional layer 1 and the functional layer 2 contain a polymer compound.

22. A method for designing the film thickness structure of an organic EL display panel, wherein In an organic EL display panel having a plurality of divided regions partitioned by partition walls and an organic electroluminescent element formed in the divided region, The plurality of divided regions have at least a first divided region and a second divided region, The organic electroluminescent elements in the first divided region and the organic electroluminescent elements in the second divided region have mutually different emission colors, wherein Each of the divided regions independently has at least a functional film in which a functional layer 1 and a functional layer 2 are laminated, The functional material for forming the functional layer 1 in the first divided region is the same as the functional material for forming the functional layer 1 in the second divided region, The functional material for forming the functional layer 2 in the first divided region is the same as the functional material for forming the functional layer 2 in the second divided region, When the functional film 1 and the functional film 2 are laminated independently in the first divided region and the second divided region, the film thicknesses of their respective films are set to the following combination: the flatness F of the film obtained by numerically calculating and adding the film thickness distribution of the functional film 1 and the film thickness distribution when forming the functional film 2 is 75% or more, The functional film 1 is a film formed by filling a functional ink for forming the functional layer 1 into the divided region in an amount required for forming the functional layer 1, and then drying under reduced pressure; the functional film 2 is a film formed by filling a functional ink for forming the functional layer 2 into the divided region in an amount required for forming the functional layer 2, and then drying under reduced pressure. Among them, the flatness F is represented by the following formula: F = M / Ap × 100(%) In the formula, Ap represents the length of the minor axis or major axis in the divided region, and M represents the length of the distribution portion having a film thickness less than 1.05 and greater than 0.95 when the film thickness distribution measured along the minor axis or major axis in the divided region is divided by the film thickness h at the center of the divided region.

23. The design method of the film thickness structure of the organic EL display panel according to claim 22, wherein the flatness F of the film in which the functional layer 1 and the functional layer 2 are laminated exhibits a value greater than either the flatness F of the functional film 1 or the flatness F of the functional film 2.

24. The design method of the film thickness structure of the organic EL display panel according to claim 22, wherein the functional film 1 is a film in which the thickest part of the film thickness is located at the central part of the divided region, the functional film 2 is a film in which the thickest part of the film thickness is located in a region other than the central part of the divided region.

25. The design method of the film thickness structure of the organic EL display panel according to claim 22, wherein, The average film thickness of the functional film 1 is thinner than the average film thickness of the functional film 2.

26. The design method of the film thickness structure of the organic EL display panel according to claim 22, wherein, The functional layer 1 and the functional layer 2 are a hole injection layer or a hole transport layer.

27. The design method of the film thickness structure of the organic EL display panel according to claim 22, wherein, The functional layer 1 and the functional layer 2 contain a polymer compound.

28. An organic electroluminescent element, which is an organic electroluminescent element having at least a functional film in which a functional layer 1 and a functional layer 2 are laminated, wherein the organic electroluminescent element is provided in a divided region partitioned by a partition wall, the functional layer 1 is a layer in which the value of the following formula is the largest among the layers constituting the functional film in the layer thickness distribution measured along the minor axis or major axis of the divided region, (Average film thickness at the central part within the divided region) - (Average film thickness at the partition wall side part within the divided region) the functional layer 2 is a layer in which the value of the following formula is the largest among the layers constituting the functional film in the layer thickness distribution measured along the minor axis or major axis of the divided region, (Average film thickness at the partition wall side part within the divided region) - (Average film thickness at the central part within the divided region) wherein, the central part refers to the inside of the region bounded by a closed curve determined by the locus of points at 60% of the position from the center of gravity to the partition wall when scanning the entire outer periphery of the divided region with a straight line passing through the center of gravity of the divided region, the partition wall side part refers to the outside of the region bounded by the closed curve within the divided region, furthermore, the closed curve may or may not include a straight line part and a corner part, the flatness F of the laminated film obtained by adding the layer thickness distributions of the functional layer 1 and the functional layer 2 exhibits a value greater than either the flatness F of the functional layer 1 or the flatness F of the functional layer 2, here, the flatness F is represented by the following formula: F = M / Ap × 100(%) In the formula, Ap represents the length of the minor axis or major axis in the divided region, and M represents the length of the distribution portion having a film thickness less than 1.05 and greater than 0.95 when the layer thickness distribution measured along the minor axis or major axis in the divided region is divided by the film thickness h at the center of the divided region.

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