JP2009054608A - Organic electroluminescence device and method for producing the same - Google Patents

Abstract

An object of the present invention is to provide an organic EL element for forming an organic layer by a discharge method such as an ink jet method and a method for manufacturing the organic EL element, and to provide an organic EL element having a high display quality and a method for manufacturing the organic EL element. .
According to the present invention, an organic EL layer has a flat organic layer, and in a pixel defined by a partition wall, the flat organic layer has a flat portion and a peripheral portion disposed around the flat portion. When the length of the flat organic layer in the cross section including the central portion of the flat organic layer in the pixel is 1, the length of the flat portion is 0.7 or more, and the flat in the pixel The object is achieved by providing an organic EL element characterized in that the cross-sectional shape of the organic layer is a shape having an inflection point in the peripheral portion.
[Selection] Figure 2

Description

  The present invention relates to an organic electroluminescence (hereinafter sometimes abbreviated as EL) element for forming an organic layer by a discharge method and a method for manufacturing the same.

  An organic EL element that sandwiches a light emitting layer between a pair of electrodes and emits light by applying a voltage between both electrodes has high visibility due to self-coloring, and unlike a liquid crystal element, it is an all-solid-state element and has excellent impact resistance. It has advantages such as high response speed, low influence of temperature change, and a large viewing angle, and its use as a light emitting element in a display device or a lighting device is drawing attention.

  In the method for producing an organic EL element, patterning of an organic layer such as a hole transport layer or a light emitting layer may be performed. Examples of the method for patterning the organic layer include a photolithography method, a mask vapor deposition method, and an ink jet method. The photolithographic method has a problem that the process is complicated and expensive, and the mask vapor deposition method requires a high-priced vacuum apparatus, and yield and cost are problems. On the other hand, the ink jet method is a simple method, and high-definition patterning is also possible.

  In the inkjet method, the drying of the micro liquid applied on the substrate is extremely fast. Furthermore, at the ends (upper end, lower end, right end, left end) of the application area where the micro liquid is applied on the substrate, the solvent molecule partial pressure evaporated from the micro liquid applied on the substrate is low, so it generally dries quickly. Start. Such a difference in the drying time of the micro liquid causes unevenness in the thickness of the organic layer within the pixel and between the pixels. Such uneven film thickness causes uneven display such as uneven brightness and uneven emission color.

  In order to solve the above problem, for example, Patent Document 1 and Patent Document 2 disclose a method of making the film thickness of the organic layer uniform in and between the pixels. In Patent Document 1, the application area of the composition containing the organic EL material and the solvent is made larger than the effective optical area, so that the environment and the drying of the composition applied in the effective optical area are uniform, The thickness of the organic layer between the pixels is made uniform. Moreover, in patent document 2, the composition containing an organic EL material and a solvent is applied to the effective optical region, and only the solvent is applied to the non-effective optical region. Thus, the solvent molecular partial pressures are made equal, and the film thickness of the organic layer is made uniform within and between the pixels.

  However, in these methods, in addition to the effective optical region, an extra region for applying the composition and the solvent is necessary, and the effective optical region becomes small. Furthermore, the method described in Patent Document 1 has a problem that the utilization efficiency of the organic EL material is low. Therefore, there is room for improvement in the method of making the film thickness of the organic layer uniform within and between the pixels.

JP 2002-222695 A JP 2006-269325 A

  The present invention has been made in view of the above circumstances, and is an organic EL element for forming an organic layer by a discharge method such as an ink jet method and a method for manufacturing the organic EL element. The main purpose is to provide.

  In order to achieve the above object, the present invention provides a substrate, a first electrode layer formed in a pattern on the substrate, a partition formed between the first electrode layers on the substrate, and the first electrode An organic EL element having an organic EL layer formed on an electrode layer and having one or more organic layers including a light emitting layer, and a second electrode layer formed on the organic EL layer, wherein the organic EL element The layer has a flat organic layer as the organic layer, and in the pixel defined by the partition, the flat organic layer has a flat portion and a peripheral portion disposed around the flat portion, When the length of the flat organic layer in the cross section including the central portion of the flat organic layer is 1, the length of the flat portion is 0.7 or more, and the cross section of the flat organic layer in the pixel Organic EL element having a shape having an inflection point at the peripheral portion To provide.

  According to the present invention, when the length of the flat organic layer in the cross section including the central portion of the flat organic layer in the pixel is 1, the length of the flat portion is 0.7 or more. The film thickness of most of the organic layer is uniform, and the display quality can be improved. Further, since the cross-sectional shape of the flat organic layer in the pixel has an inflection point in the peripheral portion, it is possible to prevent a short circuit between the electrodes.

  In the said invention, it is preferable that at least one part of the said partition wall surface has liquid repellency. For example, when the portion of the partition wall that contacts the flat organic layer and the upper surface have liquid repellency, the flat organic layer can have a predetermined cross-sectional shape, and the light emitting layer and the like can be patterned with high precision. Because it can.

  The present invention also includes a substrate, a first electrode layer formed in a pattern on the substrate, a partition wall formed between the first electrode layers on the substrate and having liquid repellency on the entire surface, and the first electrode layer. An organic EL element having an organic EL layer having one or more organic layers including a light-emitting layer and a second electrode layer formed on the organic EL layer, the organic EL element being formed on one electrode layer, The EL layer has a flat organic layer as the organic layer, and the height of the central portion of the flat organic layer in the pixel from the surface of the first electrode layer in all of the pixels defined by the partition walls, Difference in height from the surface of the first electrode layer at a predetermined portion at a distance of 0.25 from the center portion when the length of the flat organic layer in a cross section including the center portion of the flat organic layer is 1. Provided is an organic EL device characterized by having a thickness of 5 nm or less.

  According to the present invention, in all pixels, the difference between the height of the central portion of the flat organic layer from the surface of the first electrode layer and the height of the predetermined portion of the flat organic layer from the surface of the first electrode layer is a predetermined value. Since the thickness of the flat organic layer in the pixel is uniform in most cases, the shape of the flat organic layer is uniform in all the pixels, and the display quality can be improved.

  In the present invention, the flat organic layer is preferably the light emitting layer. This is because the display quality can be further improved if the light emitting layer is a flat organic layer.

Furthermore, the present invention provides a flat organic material containing an organic material and a solvent having a surface tension of 40 mN / m or less on a substrate in which a first electrode layer is formed in a pattern and a partition wall is formed between the first electrode layers. A flat organic layer forming step of forming a flat organic layer by applying a coating liquid for layer formation by a discharge method and drying the solvent so that the evaporation rate of the solvent is 1.0 × 10 ⁻³ μl / sec or more. The manufacturing method of the organic EL element characterized by having.

  According to the present invention, the coating liquid for forming a flat organic layer containing an organic material and a solvent having a predetermined surface tension is applied by a discharge method and dried so that the evaporation rate of the solvent becomes a predetermined value or more. , The solvent in the applied coating liquid for forming a flat organic layer can be immediately dried, and most of the film thickness in the pixel is uniform, and a flat organic layer having a uniform shape in all pixels is formed. can do. Therefore, an organic EL element with high display quality can be obtained. In addition, a flat organic layer as described above can be formed simply by using a coating liquid for forming a flat organic layer containing a solvent having a predetermined surface tension and drying it so that the evaporation rate becomes a predetermined value or more. An organic EL element with high display quality can be obtained by a simple method.

  In the present invention, it is preferable that at least a part of the partition wall surface has liquid repellency. For example, when the portion of the partition wall that contacts the flat organic layer and the upper surface have liquid repellency, the flat organic layer can have a predetermined cross-sectional shape as described above, and the light emitting layer and the like can be accurately This is because the patterning can be performed well.

  Furthermore, in the present invention, the flat organic layer is preferably a light emitting layer. As described above, if the light emitting layer is a flat organic layer, the display quality can be further improved.

  According to the present invention, when the length of the flat organic layer in the cross section including the central portion of the flat organic layer in the pixel is 1, the length of the flat portion is 0.7 or more. The film thickness of most of the organic layer is uniform, and the display quality can be improved. Further, since the cross-sectional shape of the flat organic layer in the pixel has an inflection point in the peripheral portion, there is an effect that a short circuit between the electrodes can be prevented.

  Hereinafter, the organic EL device of the present invention and the manufacturing method thereof will be described in detail.

A. Organic EL Element First, the organic EL element of the present invention will be described.
The organic EL device of the present invention can be divided into two modes depending on the constitution of the organic layer. Hereinafter, the description will be made separately for each aspect.

1. 1st aspect The 1st aspect of the organic EL element of this invention is a board | substrate, the 1st electrode layer formed in the pattern form on the said board | substrate, the partition formed between the said 1st electrode layers on the said board | substrate, An organic EL element having an organic EL layer formed on the first electrode layer and having one or more organic layers including a light emitting layer, and a second electrode layer formed on the organic EL layer, The organic EL layer has a flat organic layer as the organic layer, and in the pixel defined by the partition, the flat organic layer has a flat portion and a peripheral portion disposed around the flat portion, When the length of the flat organic layer in the cross section including the central portion of the flat organic layer in the pixel is 1, the length of the flat portion is 0.7 or more, and the flat organic layer in the pixel The cross-sectional shape of the layer is a shape having an inflection point at the peripheral portion. It is.

The organic EL element of this embodiment will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing an example of the organic EL element of this embodiment. In the organic EL element 1 illustrated in FIG. 1, the first electrode layer 4 is formed in a pattern on the substrate 2, and the partition walls 5 are formed so as to partition the first electrode layer 4. In addition, a hole injection layer 6 and a light emitting layer 7 are formed on the first electrode layer 4 to constitute an organic EL layer 8. A second electrode layer 9 is formed on the organic EL layer 8.

  A region defined by the partition walls 5 is a pixel 10. In FIG. 1, the light emitting layer 7 is a flat organic layer, and in the pixel 10, the light emitting layer 7 has a flat portion 11 and a peripheral portion 12 disposed around the flat portion 11.

The “flat portion” means that the difference in height of the flat organic layer from the surface of the first electrode layer is 5 nm or less with reference to the portion where the height of the flat organic layer from the surface of the first electrode layer is the lowest. An area.
Here, the flat portion can be confirmed by measuring the height of the flat organic layer from the surface of the first electrode layer in the pixel. The height of the flat organic layer from the surface of the first electrode layer in the pixel is measured by a scanning white interference method using New View 5000 manufactured by Zygo.
FIG. 2 shows the height of the light emitting layer from the surface of the first electrode layer in the pixel determined by the above method. In the organic EL element in which circular pixels 10 having a diameter of 70 μm are arranged at a pitch of 100 μm as illustrated in FIG. 3A, the central portion p of the light emitting layer (flat organic layer 17) in the pixel 10 is included. FIG. 2 shows the result of measuring the film thickness of the light emitting layer (flat organic layer 17) in the cross section, that is, the cross section along the line AA.
Here, the height of the flat organic layer from the surface of the first electrode layer in the pixel means the flat organic layer (light emitting layer 7) from the surface of the first electrode layer 4 in the pixel 10 as illustrated in FIG. Refers to height h ₁ .

  Further, the “peripheral portion” refers to a region other than the flat portion of the flat organic layer in the pixel.

  In this aspect, when the length of the flat organic layer in the cross section including the central portion of the flat organic layer in the pixel is 1, the length of the flat portion is 0.7 or more.

The “center portion of the flat organic layer in the pixel” refers to the center of gravity of the shape of the pixel.
Further, “a cross section including the central portion of the flat organic layer in the pixel” refers to a cross section including the center of gravity of the shape of the pixel. For example, as shown in FIG. 3A, when the pixel 10 has a circular shape, a cross section including a circular diameter, that is, a cross section taken along the line AA represents the central portion p of the flat organic layer 17 in the pixel 10. The cross section includes.
In this aspect, among the cross sections including the central portion of the flat organic layer in the pixel, at least one cross section in which the length of the flat portion is 0.7 or more when the length of the flat organic layer is 1 is used. I just need a place.

Further, “the length of the flat organic layer in the cross section including the central portion of the flat organic layer in the pixel” is in contact with the partition wall of the flat organic layer in the cross section including the central portion of the flat organic layer in the pixel. The distance from end to end. Specifically, as illustrated in FIG. 4, the flat organic layer 17 has a cross section including the central portion of the flat organic layer in the pixel where the distance from the end contacting the partition wall 5 of the flat organic layer 17 is the end portion. The layer length is d ₁ .

Furthermore, “the length of the flat portion (of the flat organic layer in the cross section including the central portion of the flat organic layer in the pixel)” means the end of the flat portion in the cross section including the central portion of the flat organic layer in the pixel. The distance from the part to the end. Specifically, as illustrated in FIG. 4, the distance from the end portion of the flat portion 11 of the flat organic layer 17 to the end portion of the flat organic layer 17 is a cross section including the central portion of the flat organic layer in the pixel. The length of the flat portion is d ₂ .

In this embodiment, when the length d ₁ of the flat organic layer in the cross section including the central portion of the flat organic layer in the pixel is 1, the flat portion length d ₂ is 0.7 or more. Therefore, the film thickness of most of the flat organic layer in the pixel is uniform, and it is possible to reduce luminance unevenness and color unevenness and improve display quality.

  In this embodiment, the cross-sectional shape of the flat organic layer in the pixel is a shape having an inflection point in the peripheral portion.

The “shape having an inflection point” refers to a shape having a point that changes from an upward convex state to a concave state or a point that changes from an upward concave state to an upward convex state.
In addition, “the shape having an inflection point in the peripheral part” means that the peripheral part is arranged at both ends of the flat part in the cross section of the flat organic layer in the pixel. A shape having a point that changes from a convex state upward to a concave state or a point that changes from a concave state upward to a convex state.
For example, the cross-sectional shape of the flat organic layer 17 shown in FIG. 4 is a shape having inflection points i ₁ and i ₂ at the peripheral portion 12. These inflection points i ₁ and i ₂ can be said to be points that change from an upwardly convex state to an upwardly concave state, and also points that change from an upwardly concave state to an upwardly convex state. I can say that.
On the other hand, the shape having no inflection point refers to a concave shape of the organic layer 107 as shown in FIG. 5, for example.

  Here, the cross-sectional shape of the flat organic layer is a shape having an inflection point in the peripheral portion, as described above, in the cross-section including the central portion of the flat organic layer in the pixel, the first electrode layer in the pixel. It can be confirmed by measuring the height of the flat organic layer from the surface, or can be confirmed by an electron micrograph of a cross section including the central portion of the flat organic layer in the pixel.

  In this embodiment, since the cross-sectional shape of the flat organic layer in the pixel has an inflection point in the peripheral portion, the occurrence of cracks and chips in the flat organic layer is suppressed, and the organic layer and the partition wall are suppressed. It is possible to prevent a short circuit between the electrodes around the boundary.

  Hereinafter, each structure of the organic EL element of this aspect is demonstrated.

(1) Organic EL layer The organic EL layer in this embodiment is formed on the first electrode layer and has one or more organic layers including a light emitting layer, and has a flat organic layer as the organic layer. is there. That is, the organic EL layer is a layer including at least a light emitting layer, and the layer configuration is a layer having one or more organic layers.

Examples of the organic layer formed in the organic EL layer other than the light emitting layer include a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer. The hole transport layer is often integrated with the hole injection layer by imparting a hole transport function to the hole injection layer. Further, the electron transport layer may be integrated with the electron injection layer by imparting an electron transport function to the electron injection layer.
In addition, as an organic layer formed in the organic EL layer, it prevents holes or electrons from penetrating like a carrier block layer and further prevents exciton diffusion and confines excitons in the light emitting layer. And a layer for increasing the recombination efficiency.

Thus, the organic EL layer often has a laminated structure in which various layers are laminated, and there are many kinds of such laminated structures. For example, hole injection layer / light emitting layer, hole injection layer / hole transport layer / light emitting layer, hole injection layer / light emitting layer / electron transport layer, hole injection layer / hole transport layer / light emitting layer / electron transport Examples include a laminated structure such as a layer.
Hereinafter, each structure of the organic EL layer will be described.

(I) Flat organic layer The flat organic layer in this aspect has a flat part and the peripheral part arrange | positioned around this flat part in a pixel.

  As for the surface flatness of the flat portion, the difference in height of the flat organic layer from the surface of the first electrode layer is 5 nm or less with reference to the portion where the height of the flat organic layer from the surface of the first electrode layer is the lowest. , Preferably 3 nm or less, more preferably 2 nm or less. This is because the display quality can be further improved if the surface flatness is within the above range.

  Further, when the length of the flat organic layer in the cross section including the central portion of the flat organic layer in the pixel is 1, the length of the flat portion is 0.7 or more, preferably 0.8 or more. . This is because the display quality can be further improved if the length of the flat portion is in the above range. On the other hand, the flat organic layer has a peripheral portion around the flat portion, but the upper portion is not particularly limited because the longer the flat portion, the better.

  Of the cross section including the central portion of the flat organic layer in the pixel (the cross section including the center of gravity of the shape of the pixel), the length of the flat portion when the length of the flat organic layer in at least one of the cross sections is 1. However, it is preferable that the length of the flat portion is 0.7 or more when the length of the flat organic layer is 1 in any of the cross sections.

  Further, the cross-sectional shape of the flat organic layer in the pixel is a shape having an inflection point in the peripheral portion. In this aspect, regardless of the shape of the pixel, the cross-sectional shape of the flat organic layer in the pixel is a shape having an inflection point in the peripheral portion.

As illustrated in FIG. 4, since the flat organic layer 17 has a cross-sectional shape having inflection points i ₁ and i ₂ in the peripheral portion 12, the film thickness changes stepwise. On the other hand, as illustrated in FIG. 5, when the cross-sectional shape of the organic layer 107 is a shape having no inflection point, the film thickness of the organic layer 107 changes continuously. Therefore, the change in the film thickness differs depending on whether the cross-sectional shape of the organic layer is a shape having an inflection point or a shape having no inflection point. In this aspect, since the cross-sectional shape of the flat organic layer is a shape having an inflection point, it is possible to effectively prevent the flat organic layer from being cracked or chipped.

Specifically, the height of the flat portion of the flat organic layer from the surface of the first electrode layer varies depending on the type of the flat organic layer, but is preferably about 0.5 nm to 500 nm, more preferably 5 nm to 300 nm. And more preferably within a range of 10 nm to 250 nm. When the height of the flat portion of the flat organic layer from the surface of the first electrode layer is in the above range, the function of each layer can be sufficiently exhibited when the flat organic layer is each layer described later.
Note that the height of the flat portion of the flat organic layer from the surface of the first electrode layer means the height h ₂ of the flat portion 11 of the flat organic layer 17 from the surface of the first electrode layer 4 as illustrated in FIG. .

Further, as a relationship between the thickness of the flat portion of the flat organic layer and the thickness of the flat organic layer at the inflection point, the thickness of the flat organic layer at the inflection point is 1 of the thickness of the flat portion of the flat organic layer. It is preferably about 5 to 15 times, more preferably about 2 to 10 times. This is because the above-described relationship can further prevent the flat organic layer from being cracked or chipped.
Note that the thickness of the flat portion of the flat organic layer refers to the thickness h ₃ of the central portion of the flat organic layer 17 as illustrated in FIG. In addition, as illustrated in FIG. 6, the thickness of the flat organic layer at the inflection point is a base layer at the center of the flat organic layer 17 in a cross section including the central portion of the flat organic layer 17 in the pixel 10. (Layer formed immediately below the flat organic layer) When the height from the surface of the first electrode layer 4 of 16 is the reference line L, the reference of the flat organic layer 17 at the inflection points i ₁ and i ₂ This refers to the height (thickness) h ₄ from the line L.

  Specifically, the thickness of the flat portion of the flat organic layer varies depending on the type of the flat organic layer, but is preferably about 0.5 nm to 500 nm, more preferably in the range of 5 nm to 300 nm, and still more preferably. It is in the range of 10 nm to 250 nm. If the thickness of the flat part of the said flat organic layer is the said range, when a flat organic layer is each layer mentioned later, the function of each layer can fully be exhibited.

  Specifically, the thickness of the flat organic layer at the inflection point varies depending on the thickness of the partition wall, but is preferably about 1.25 nm to 1250 nm, more preferably in the range of 12.5 nm to 750 nm. Of these, more preferably in the range of 15 nm to 650 nm. If the thickness of the flat organic layer at the inflection point is within the above range, it is possible to further prevent the flat organic layer from being cracked or chipped.

Here, the height of the flat portion of the flat organic layer from the surface of the first electrode layer, the thickness of the flat portion of the flat organic layer, and the thickness of the flat organic layer at the inflection point are manufactured by Zygo, New View. Measured by scanning white light interferometry using 5000.
The inflection point is confirmed by measuring the height of the flat organic layer from the surface of the first electrode layer in the pixel as described above in the cross section including the central portion of the flat organic layer in the pixel, or It can be confirmed by an electron micrograph of a cross section including the central portion of the flat organic layer in the pixel.

  The flat organic layer may be any of a light emitting layer, a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, a carrier block layer, and the like. Further, the flat organic layer may be a single layer or two or more layers. For example, when the organic EL layer has a layered structure of a hole injection layer / hole transport layer / light emitting layer, the flat organic layer may be only the light emitting layer, or two layers of the hole transport layer and the light emitting layer. There may be three layers of a hole injection layer, a hole transport layer, and a light emitting layer.

  Among these, the flat organic layer is preferably at least a light emitting layer. In general, when a voltage is applied to an organic EL element, light emission starts from a portion where the thickness of the light emitting layer is thin. Therefore, if there are many portions having a uniform thickness, the light emitting region can be expanded. Therefore, if the light emitting layer is a flat organic layer, luminance unevenness and emission color unevenness can be effectively suppressed, and display quality can be further improved.

  Further, the flat organic layer is preferably a light emitting layer and a hole transport layer, or a light emitting layer, a hole transport layer and a hole injection layer. In general, when an organic EL device is produced, it is more stable to stack an organic layer from the anode side, and therefore it is preferable to stack a hole injection layer, a hole transport layer, and a light emitting layer in this order. Therefore, if the hole injection layer and the hole transport layer formed under the light emitting layer are also flat organic layers, the film thickness of the most part of the light emitting layer in the pixel can be made uniform, further improving the display quality. Can be increased.

  Hereinafter, the case where the flat organic layer is each of the above layers will be described separately.

(Light emitting layer)
When the flat organic layer is a light emitting layer, examples of the organic material constituting the light emitting layer include light emitting materials such as a dye material, a metal complex material, and a polymer material.

Examples of dye-based materials include cyclopentadiene derivatives, tetraphenylbutadiene derivatives, triphenylamine derivatives, arylamine derivatives, oxadiazole derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylpyrazine derivatives, distyrylarylene. Derivatives, silole derivatives, carbazole derivatives, anthracene derivatives, dinaphthylanthracene derivatives, phenylanthracene derivatives, thiophene ring compounds, pyridine ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, trifumanylamine derivatives, coumarin derivatives, oxadiazole dimers , Pyrazoline dimer, phenanthroline and the like. Moreover, the compound which introduce | transduced the fluorene group and the spiro group into these can also be used.
Specifically, as the triphenylamine derivative, N, N′-bis- (3-methylphenyl) -N, N′-bis- (phenyl) -benzidine (TPD), 4,4,4-tris (3 -Methylphenylphenylamino) triphenylamine (MTDATA) and the like. Examples of the arylamine derivative include bis (N- (1-naphthyl-N-phenyl) benzidine) (α-NPD). Examples of the oxadiazole derivative include (2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole) (PBD). Examples of the dinaphthylanthracene derivative include 9,10-di-2-naphthylanthracene (DNA). Examples of the carbazole derivative include 4,4-N, N′-dicarbazole-biphenyl (CBP), 1,4-bis (2,2-diphenylvinyl) benzene (DPVBi), and the like. Examples of phenanthrolines include bathocuproin and bathophenanthroline. These materials may be used alone or in combination of two or more.

Examples of the metal complex-based material include Al, Zn, Be, Ir, Pt, etc. as a central metal, or rare earth metals such as Tb, Eu, Dy, etc., and oxadiazole, thiadiazole, phenylpyridine as a ligand. , Phenylbenzimidazole, metal complexes having a quinoline structure, and the like. Examples of the metal complex include an aluminum quinolinol complex, a benzoquinolinol beryllium complex, a benzoxazole zinc complex, a benzothiazole zinc complex, an azomethylzinc complex, a porphyrin zinc complex, a europium complex, an iridium metal complex, and a platinum metal complex.
Specifically, tris (8-quinolinol) aluminum complex (Alq ₃ ), bis (2-methyl-8-quinolinato) (p-phenylphenolate) aluminum complex (BAlq), tri (dibenzoylmethyl) phenanthroline europium complex And bis (benzoquinolinolato) beryllium complex (Bebq). These materials may be used alone or in combination of two or more.

  Examples of the polymer material include polyparaphenylene vinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyvinylcarbazole, polyfluorenone derivatives, polyfluorene derivatives, polyquinoxaline derivatives, polydialkylfluorene derivatives, and Examples thereof include copolymers thereof. Moreover, what polymerized the said pigment-type luminescent material and metal complex type | system | group luminescent material is also mentioned.

  Further, a dopant that emits fluorescence or phosphorescence may be added to the light emitting layer for the purpose of improving the light emission efficiency and changing the light emission wavelength. Examples of such dopants include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squalium derivatives, porphyrin derivatives, styryl dyes, tetracene derivatives, pyrazoline derivatives, decacyclene, phenoxazone, quinoxaline derivatives, carbazole derivatives, fluorene derivatives, and the like. Can be mentioned. Specifically, 1-tert-butyl-perylene (TBP), coumarin 6, Nile red, 1,4-bis (2,2-diphenylvinyl) benzene (DPVBi), 1,1,4,4-tetraphenyl -1,3-butadiene (TPB).

Furthermore, as a phosphorescent dopant, an organometallic complex that has a heavy metal ion such as platinum or iridium at the center and exhibits phosphorescence can be used. Specifically, Ir (ppy) ₃ , (ppy) ₂ Ir (acac), Ir (BQ) ₃ , (BQ) ₂ Ir (acac), Ir (THP) ₃ , (THP) ₂ Ir (acac), Ir (BO) ₃ , (BO) ₂ (acac), Ir (BT) ₃ , (BT) ₂ Ir (acac), Ir (BTP) ₃ , (BTP) ₂ Ir (acac), FIr6, PtOEP, etc. are used. be able to.

  Here, the light emitting layer has a function of emitting light by providing a recombination field between electrons and holes. The light emitting layer may emit blue light, green light, yellow light, orange light, red light, or other single color light, or may emit white light due to a mixture of multiple colors. It may be. White light emission can be obtained by superimposing light emission from a plurality of light emitters. The light emitting layer that emits white light may be, for example, one that obtains white light emission by superimposing two-color light emission of two kinds of light emitters having a predetermined peak wavelength, and three kinds of light emitters having a predetermined peak wavelength. It is also possible to obtain white light emission by superimposing these three colors.

(Hole transport layer)
When the flat organic layer is a hole transport layer, the organic material constituting the hole transport layer may be a hole transport material that can stably transport holes injected from the anode into the light emitting layer. There is no particular limitation. Among these, the hole transporting material preferably has a high hole mobility. Furthermore, the hole transporting material is preferably a material that can prevent penetration of electrons that have moved from the cathode. This is because the recombination efficiency of holes and electrons in the light emitting layer can be increased.

  Examples of such hole transporting materials include arylamine derivatives, anthracene derivatives, carbazole derivatives, thiophene derivatives, fluorene derivatives, distyrylbenzene derivatives, and spiro compounds. Specific examples of the arylamine derivative include bis (N- (1-naphthyl-N-phenyl) -benzidine (α-NPD), N, N′-bis- (3-methylphenyl) -N, N′-bis. -(Phenyl) -benzidine (TPD), 4,4,4-tris (3-methylphenylphenylamino) triphenylamine (MTDATA), copoly [3,3'-hydroxy-tetraphenylbenzidine / diethylene glycol] carbonate (PC -TPD-DEG), etc. Specific examples of anthracene derivatives include 9,10-di-2-naphthylanthracene (DNA), poly [(9,9-dioctylfluorenyl-2,7- Diyl) -co- (9,10-anthracene)], etc. Specific examples of the carbazole derivative include 4, -N, N'-dicarbazole-biphenyl (CBP), polyvinylcarbazole (PVK), etc. Specific examples of thiophene derivatives include poly [(9,9-dioctylfluorenyl-2,7- Diyl) -co- (bithiophene)] etc. Specific examples of the fluorene derivative include poly [(9,9-dioctylfluorenyl-2,7-diyl) -co- (4,4 ′). -(N- (4-sec-butylphenyl)) diphenylamine)] (TFB), etc. Specific examples of the distyrylbenzene derivative include 1,4-bis (2,2-diphenylvinyl) benzene. (DPVBi) etc. Specific examples of the spiro compound include poly [(9,9-dioctylfluorenyl-2,7-diyl) -al. t-co- (9,9'-spiro-bifluorene-2,7-diyl)], etc. These materials may be used alone or in combination of two or more.

(Hole injection layer)
When the flat organic layer is a hole injection layer, the organic material constituting the hole injection layer is particularly limited as long as it is a hole injection material that can stabilize injection of holes into the light emitting layer. Is not to be done. Examples of such hole injecting materials include arylamine derivatives, porphyrin derivatives, carbazole derivatives, and conductive polymers such as polyaniline derivatives, polythiophene derivatives, and polyphenylene vinylene derivatives. Specifically, as the arylamine derivative, bis (N- (1-naphthyl-N-phenyl) benzidine (α-NPD), N, N′-bis- (3-methylphenyl) -N, N′- Bis- (phenyl) -benzidine (TPD), copoly [3,3′-hydroxy-tetraphenylbenzidine / diethylene glycol] carbonate (PC-TPD-DEG), 4,4,4-tris (3-methylphenylphenylamino) Triphenylamine (MTDATA), etc. Examples of the carbazole derivative include polyvinyl carbazole (PVK), and examples of the polythiophene derivative include poly (3,4-ethylenedioxythiophene) -polystyrene sulfonic acid (PEDOT-PSS). Etc.

  The above porphyrin derivatives and arylamine derivatives may be mixed with inorganic acids such as Lewis acid, tetracyanoquinodimethane (F4-TCNQ), iron chloride, vanadium and molybdenum.

(Electron transport layer)
When the flat organic layer is an electron transport layer, the organic material constituting the electron transport layer is not particularly limited as long as it is an electron transport material that can stably transport electrons injected from the cathode into the light emitting layer. It is not something. Especially, it is preferable that an electron transport material has a high electron mobility. Furthermore, it is preferable that the electron transporting material can prevent penetration of holes that have moved from the positive electrode. This is because the recombination efficiency of holes and electrons in the light emitting layer can be increased.
Examples of such an electron transporting material include oxadiazoles, triazoles, phenanthrolines, silole derivatives, cyclopentadiene derivatives, aluminum complexes, and the like. Specific examples of the oxadiazole derivative include (2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole) (PBD) and the like, and phenanthroline. Examples thereof include bathocuproin, bathophenanthroline and the like, and aluminum complexes include tris (8-quinolinol) aluminum complex (Alq ₃ ), bis (2-methyl-8-quinolinato) (p-phenylphenolate) aluminum complex (BAlq ) And the like.

  In addition, since the formation method of a flat organic layer is described in detail in "B. Manufacturing method of organic EL element" mentioned later, description here is abbreviate | omitted.

(Ii) Other layers As described above, the organic EL layer may have other organic layers in addition to the flat organic layer. The other organic layer is appropriately selected according to the function of the flat organic layer. For example, as shown in FIG. 1, the organic EL layer 8 may be formed by stacking another organic layer (hole injection layer 6) and a flat organic layer (light emitting layer 7).

  Specifically, when the flat organic layer is a light emitting layer, examples of the other organic layer include a hole injection layer, a hole transport layer, and an electron transport layer. When the flat organic layer is a light emitting layer and a hole transport layer, examples of other organic layers include a hole injection layer and an electron transport layer.

  A hole injection layer may be formed between the anode and the light emitting layer, or between the anode and the hole transport layer. The constituent material of the hole injection layer is not particularly limited as long as it is a material that can stabilize the injection of electrons into the light emitting layer, and when the flat organic layer is a hole injection layer. The constituent material of a positive hole injection layer can be illustrated.

In addition, an inorganic material such as a metal oxide or a carbide can be used for the hole injection layer. Examples thereof include metal oxides such as vanadium oxide, molybdenum oxide, ruthenium oxide, aluminum oxide, and titanium oxide; and carbides such as amorphous carbon, C ₆₀ , and carbon nanotubes.

  Furthermore, a material having a bonding group with an electrode can be used for the hole injection layer. Examples of the material having a bonding group with the electrode include a phosphoric acid compound, a carboxylic acid compound, a sulfonic acid compound, and a silane coupling agent. Specific examples include 4- (trifluoromethyl) benzenesulfonyl chloride, 4-chlorophenyl phosphorodichloridate, 9-fluorenylmethyl chloroformate and the like.

  The thickness of the hole injection layer is not particularly limited as long as the hole injection function is sufficiently exerted. Moreover, as a formation method of a positive hole injection layer, wet methods, such as a spin coat method and an inkjet method, and dry methods, such as a vacuum evaporation method, can be used, for example.

  In addition, an electron transport layer may be formed between the light emitting layer and the cathode, or between the light emitting layer and the electron injection layer. The constituent material of the electron transport layer is not particularly limited as long as it is a material capable of transporting electrons injected from the cathode into the light emitting layer, and the case where the flat organic layer is an electron transport layer. The constituent material of an electron carrying layer can be illustrated.

  The thickness of the electron transport layer is not particularly limited as long as the electron transport function is sufficiently exerted. Moreover, as a formation method of an electron carrying layer, wet methods, such as a spin coat method and an inkjet method, and dry methods, such as a vacuum evaporation method, can be used, for example.

  Further, an electron injection layer may be formed between the light emitting layer and the cathode or between the electron transport layer and the cathode. The constituent material of the electron injection layer is not particularly limited as long as it can stabilize the injection of electrons into the light emitting layer. For example, alkali metal such as strontium, calcium, lithium, cesium or alkali Earth metal simple substance; Alkali metal or alkaline earth metal oxide such as magnesium oxide, strontium oxide, lithium oxide; lithium fluoride, magnesium fluoride, strontium fluoride, calcium fluoride, barium fluoride, fluoride Fluorides of alkali metals or alkaline earth metals such as cesium; organic complexes of alkali metals such as sodium polymethyl methacrylate polystyrene sulfonate.

  The thickness of the electron injection layer is not particularly limited as long as the electron injection function is sufficiently exerted. As a method for forming the electron injection layer, a dry method such as a vacuum evaporation method can be used.

(2) Pixel The pixel in this embodiment is defined by a partition wall.

  The shape of the pixel can be the same as the shape of a general pixel, for example, a point-symmetric shape such as a circle or a square, or a point-symmetric shape such as a rectangle, a track shape, or an ellipse, but a line-symmetric shape. The shape can be mentioned. When the shape of the pixel is a square or a rectangle, since the organic layer forming coating liquid for forming the organic layer has a surface tension, as illustrated in FIG. It is preferable to be rounded.

  Further, the pixel arrangement may be a mosaic arrangement, a delta arrangement, a stripe arrangement, or the like. Furthermore, the pitch of the pixels is preferably equal in the X direction and equal in the Y direction. In particular, both the X and Y directions are preferably equal. This is because, when the flat organic layer is formed, the applied organic layer forming coating solution can be uniformly dried in all pixels.

  The size of the pixel is not particularly limited, and is appropriately selected according to the shape of the pixel. For example, if the pixel has a circular shape, the diameter is preferably about 1 μm to 200 μm.

(3) Partition Wall The partition wall in this embodiment is formed between the first electrode layers on the substrate, and is formed so that at least a part of the partition wall is in contact with the first electrode layer. Since the partition walls are formed, when the organic layer forming coating solution for forming the organic layer is discharged, the organic layer forming coating solution can be applied to a predetermined region with high accuracy.

It is preferable that at least a part of the surface of the partition wall has liquid repellency. In particular, it is preferable that the portion in contact with the flat organic layer and the upper surface have liquid repellency. Since the portion of the partition that is in contact with the flat organic layer is liquid repellent, a flat organic layer having a predetermined cross-sectional shape can be obtained. Further, if the upper surface of the partition wall is liquid repellent, it is possible to effectively prevent the light emitting layer forming coating liquid from spreading to adjacent pixels when the light emitting layer is patterned by the discharge method.
Note that the upper surface of the partition wall refers to the surface of the partition wall on the second electrode layer side.

  If the part and upper surface which contact the flat organic layer of a partition have lyophobic property, as illustrated in FIG. 7A, the partition 5 has a lyophilic partition having lyophilicity from the substrate 2 side. 5a and a liquid repellent partition wall 5b having liquid repellency may be laminated.

In particular, it is preferable that the entire surface of the partition wall has liquid repellency.
“The entire surface of the partition wall has liquid repellency” means that both the side surface and the upper surface of the partition wall have liquid repellency.

Conventionally, in order to form an organic layer having a cross-sectional shape as shown in FIG. 5, at least a side surface of the partition wall, that is, a portion in contact with the organic layer has to be lyophilic. When the partition wall has such a configuration, for example, a partition wall having lyophilicity and a partition wall having liquid repellency are laminated, or a side surface of the partition wall is made lyophilic and an upper surface is made liquid repellant. .
On the other hand, in the present invention, as described later in “B. Manufacturing method of organic EL element”, a coating solution for forming a flat organic layer containing a solvent having a predetermined surface tension is applied, and the evaporation rate is applied. By drying so that becomes a predetermined value or more, a flat organic layer having a flat portion and having a predetermined cross-sectional shape can be formed. Therefore, it is not necessary that the partition walls have lyophilicity, and it is necessary to laminate the partition walls having lyophilicity and the partition walls having liquid repellency, or to make the side surfaces of the partition walls lyophilic and to make the upper surface lyophobic. In addition, the manufacturing process of the organic EL element can be simplified.

  As the liquid repellency of the partition wall, the contact angle of the partition wall surface with water is preferably 70 ° or more, more preferably 75 ° or more, and further preferably 80 ° or more. If the contact angle with respect to the water of the partition wall surface is the said range, it can be set as the flat organic layer which has a predetermined | prescribed cross-sectional shape.

  Moreover, an organic solvent is usually used for the coating liquid for forming an organic layer for forming a light emitting layer or the like. The partition walls preferably have a high contact angle with respect to the organic solvent. Specifically, the contact angle with respect to a liquid having a surface tension of 29 mN / m (normal temperature) is preferably 40 ° or more, more preferably 45 ° or more, and further preferably 50 ° or more.

  On the other hand, when the partition wall comprises a lyophilic partition wall and a lyophobic partition wall, the lyophilic property of the lyophilic partition wall is preferably such that the contact angle of the surface of the lyophilic partition wall with water is 20 ° or less. Preferably it is 10 degrees or less, More preferably, it is 5 degrees or less. Further, the contact angle with respect to a liquid having a surface tension of 29 mN / m (normal temperature) is preferably 20 ° or less, more preferably 10 ° or less, and further preferably 5 ° or less.

  The contact angle with the liquid was measured at a temperature of 23 ° C., and the contact angle with the liquid was measured using a contact angle measuring device (CA-Z type manufactured by Kyowa Interface Science Co., Ltd.). 30 seconds later) and obtained from the result.

  In the present invention, examples of a method for imparting the above-described liquid repellency to the partition include a method of forming the partition using a liquid repellent material and a method of lyophobic the partition surface after forming the partition. Among these, it is preferable to use a liquid repellent material. This is because the manufacturing process of the organic EL element can be simplified.

  When the partition wall is formed using a liquid repellent material, examples of the liquid repellent material include a resin material having a liquid repellent property and a resin material to which a liquid repellent is added.

Examples of the resin material in which the resin material itself has liquid repellency include fluorine resins such as polytetrafluoroethylene (PTFE), silicone resins, and the like.
In this case, the resin material itself may use only a resin material having liquid repellency, or another general-purpose material may be mixed with the resin material itself having liquid repellency. In the latter case, the mixing ratio is appropriately adjusted so as to satisfy the above liquid repellency.

  Further, when using a resin material to which a liquid repellent is added, the liquid repellent is not particularly limited as long as it does not adversely affect the organic EL layer. For example, a fluorine resin, a silicone resin And a copolymer oligomer having a perfluoroalkyl group-containing acrylate or methacrylate as a main component. Among them, it is preferable to use a copolymer oligomer mainly composed of a perfluoroalkyl group-containing acrylate or methacrylate. Moreover, as a commercial item, surflon (random type oligomer; made by Seimi Chemical Co., Ltd.), Aron G (graft type oligomer; made by Toa Gosei Chemical Co., Ltd.), Modiva F (block type oligomer; made by Nippon Oil & Fats Co., Ltd.) and the like can be mentioned. .

  The amount of the liquid repellent added to the resin material varies depending on the type of liquid repellent and the type of resin, but should be about 1 to 20 parts by weight with respect to 100 parts by weight of the resin material. Is preferable, and more preferably within the range of 5 to 10 parts by weight.

  In the case of using a resin material to which a liquid repellent is added, as this resin material, those generally used for partition walls can be used, and examples thereof include novolak resins, polyimides, and acrylates.

  Even when the resin material itself uses a resin material having liquid repellency, the above-described liquid repellent may be further added as necessary.

  In addition, when the partition wall surface is subjected to a liquid repellency treatment after the partition wall formation, the constituent material of the partition wall is not particularly limited as long as the liquid repellent treatment is possible, and those generally used for the partition wall are used. Examples thereof include novolac resins and polyimide.

  The method for repelling the partition walls is not particularly limited. For example, the surface treatment method using a liquid repellent treatment agent such as a silicone compound or a fluorine-containing compound, or the surface treatment method using a fluorocarbon gas plasma. (Plasma treatment). Among these, plasma treatment is preferable. This is because the plasma treatment can selectively repel organic substances. For example, when a partition is formed on a first electrode layer such as an ITO film, the first electrode layer can be made liquid-repellent without making the first electrode layer liquid-repellent. Therefore, by performing plasma treatment on the entire surface of the substrate, only the partition wall surface can be made liquid repellent.

Examples of the fluorocarbon gas used in the plasma treatment include CF ₄ , C ₂ F ₆ , C ₃ F ₈ , c-C ₄ F ₈ , CCl ₂ F ₂ , CClF ₃ , C ₂ Cl ₂ F ₄ , C ₂ ClF ₅ , CBrF ₃ , CHF ₃ , C ₂ H ₃ F ₃ , CH ₃ CHF ₂ , NF ₃ , SF _{6 and the} like can be used, and among them, CF ₄ gas is preferably used.

  Further, in the surface treatment using the fluorocarbon gas plasma, the surface treatment using the oxygen gas plasma may be performed in advance. In this way, the surface treatment using oxygen gas plasma is performed to make the first electrode layer lyophilic, and then the surface treatment using fluorocarbon gas plasma is performed to make only the partition wall lyophobic, This is because the coating liquid for forming an organic layer can be easily applied on the first electrode layer.

When the partition wall comprises a lyophilic partition wall and a liquid repellent partition wall, examples of the constituent material of the lyophilic partition wall include SiO ₂ and TiO ₂ .

  The cross-sectional shape of the partition wall is not particularly limited, but is preferably a forward tapered shape and a rectangular shape in order to make the cross-sectional shape of the flat organic layer a predetermined shape.

  Further, the thickness of the partition wall is set to about 1 μm to 5 μm, and preferably within the range of 1 μm to 2 μm.

The position of the partition is not particularly limited as long as the partition is formed between the first electrode layers on the substrate so that at least a part of the partition is in contact with the first electrode layer. For example, in FIG. 1 and FIG. 7A, the partition wall 5 is formed so as to cover the end portion of the first electrode layer 4.
Further, as illustrated in FIG. 7B, the partition wall 5 may be formed on the first electrode layer 4.

  In addition, examples of the method for forming the partition include a photolithography method.

(4) First electrode layer and second electrode layer The first electrode layer in this embodiment is formed on the substrate in a pattern. Moreover, the 2nd electrode layer in this aspect is formed on an organic EL layer.

  Any of the first electrode layer and the second electrode layer may be an anode or a cathode. When producing the organic EL element of this aspect, normally, an organic EL layer is formed on a 1st electrode layer, and a 2nd electrode layer is formed on this organic EL layer. In general, when an organic EL element is produced, the organic EL element can be produced more stably by laminating from the anode side. Therefore, it is preferable that the first electrode layer is an anode and the second electrode layer is a cathode.

  Of the first electrode layer and the second electrode layer, the electrode serving as the light extraction surface needs to be transparent. On the other hand, the electrode opposite to the light extraction surface may or may not be transparent.

  The first electrode layer and the second electrode layer preferably have a low resistance, and generally a metal material that is a conductive material is used, but an organic compound or an inorganic compound may be used.

  As a material used for the anode, a conductive material having a large work function is preferably used so that holes can be easily injected. For example, metals such as Au, Ta, W, Pt, Ni, Pd, Cr, Cu, Mo, alkali metals, alkaline earth metals; oxides of these metals; Al alloys such as AlLi, AlCa, AlMg, MgAg, etc. Mg alloys, Ni alloys, Cr alloys, alkali metal alloys, alkaline earth metal alloys, etc .; inorganic such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide Examples include oxides; conductive polymers such as metal-doped polythiophene, polyaniline, polyacetylene, polyalkylthiophene derivatives, and polysilane derivatives; α-Si, α-SiC; and the like. These conductive materials may be used alone or in combination of two or more. When two or more types are used, layers made of each material may be stacked.

  As a material used for the cathode, a conductive material having a small work function is preferably used so that electrons can be easily injected. Examples thereof include magnesium alloys such as MgAg, aluminum alloys such as AlLi, AlCa, and AlMg, and alloys of alkali metals and alkaline earth metals such as Li, Cs, Ba, Sr, and Ca.

  As a method for forming the first electrode layer and the second electrode layer, a general electrode forming method can be used. For example, physical vapor deposition such as vacuum vapor deposition, sputtering, EB vapor deposition, and ion plating. (PVD) method, chemical vapor deposition (CVD) method, etc. can be mentioned. Further, the patterning method of the first electrode layer and the second electrode layer is not particularly limited as long as it can be accurately formed into a desired pattern. Specifically, a photolithography method or the like is used. Can be mentioned.

(5) Substrate The substrate used in this embodiment supports the first electrode layer, the organic EL layer, and the second electrode layer.
When the first electrode layer has a predetermined strength, the first electrode layer itself can be a support, but the first electrode layer may be formed on a substrate having a predetermined strength.

Although it does not specifically limit as a board | substrate, In general, since it is preferable to make the board | substrate side into the light extraction surface, it is preferable that it is transparent. As such a substrate, for example, a glass substrate such as soda lime glass, alkali glass, lead alkali glass, borosilicate glass, aluminosilicate glass, or silica glass; a resin substrate that can be formed into a film can be used. .
The resin used for the resin substrate is preferably one having relatively high solvent resistance and heat resistance. Specifically, fluorine resin, polyethylene, polypropylene, polyvinyl chloride, polyvinyl fluoride, polystyrene, ABS resin, polyamide, polyacetal, polyester, polycarbonate, modified polyphenylene ether, polysulfone, polyarylate, polyetherimide, polyether mon Phon, Polyamideimide, Polyimide, Polyphenylene sulfide, Liquid crystalline polyester, Polyethylene terephthalate, Polybutylene terephthalate, Polyethylene naphthalate, Polymicroxylene dimethylene terephthalate, Polyoxymethylene, Polyethersulfone, Polyetheretherketone, Polyacrylate, Acrylonitrile -Styrene resin, phenol resin, urea resin, melamine resin, unsaturated polyester resin, Poxy resin, polyurethane, silicone resin, amorphous polyolefin and the like can be mentioned. Moreover, these copolymers can also be used. Further, if necessary, a substrate having a gas barrier property that blocks gas such as moisture and oxygen may be used.

  The thickness of the substrate is appropriately selected depending on the constituent material of the substrate and the use of the organic EL element. Specifically, the thickness of the substrate is about 0.005 mm to 5 mm.

2. Second aspect A second aspect of the organic EL device of the present invention is formed between the substrate, the first electrode layer formed in a pattern on the substrate, and the first electrode layer on the substrate. A partition having liquid repellency, an organic EL layer formed on the first electrode layer and including one or more organic layers including a light emitting layer, and a second electrode layer formed on the organic EL layer. The organic EL element includes the organic EL layer having a flat organic layer as the organic layer, and in all of the pixels defined by the partition wall, the first portion of the central portion of the flat organic layer in the pixel. When the height from the surface of one electrode layer and the length of the flat organic layer in a cross section including the central portion of the flat organic layer is 1, the predetermined portion of the predetermined portion located at a distance of 0.25 from the central portion. The difference from the height from the surface of one electrode layer is 5 nm or less. Is.

The organic EL element of this embodiment will be described with reference to the drawings.
FIG. 8 is a schematic cross-sectional view showing an example of the organic EL element of this embodiment. In the organic EL element 1 illustrated in FIG. 8, the first electrode layer 4 is formed in a pattern on the substrate 2, and the partition wall 5 is formed so as to partition the first electrode layer 4. Further, a hole injection layer 6 and a light emitting layer 7 are formed on the first electrode layer 4 to constitute an organic EL layer 8. A second electrode layer 9 is formed on the organic EL layer 8. A region defined by the partition walls 5 is a pixel 10, and the light emitting layer 7 is a flat organic layer in FIG.

FIG. 9 is an enlarged view of FIG. In FIG. 9, the second electrode layer is omitted. As illustrated in FIG. 9, the height of the central portion 21 of the light emitting layer 7 (flat organic layer) in the pixel 10 from the surface of the first electrode layer 4 is h ₅ . Further, in the cross section including the central portion 21 of the light emitting layer 7 (flat organic layer), when the length d ₃ of the flat organic layer is 1, predetermined portions 22a and 22b at a predetermined distance d ₄ from the central portion 21. The height from the surface of the first electrode layer 4 is h ₆ and h ₇ , respectively. The height h ₅ of the central portion 21, the difference between the height h ₆ of a predetermined portion 22a is less than a predetermined value, also the height h ₅ of the central portion 21, the height of the predetermined portion 22b h ₇ And the difference is less than or equal to a predetermined value.

Note that “the central portion of the flat organic layer in the pixel” is the same as that described in the first embodiment, and thus the description thereof is omitted here.
Further, “the height of the central portion of the flat organic layer in the pixel from the surface of the first electrode layer” means the central portion 21 of the flat organic layer (light emitting layer 7) in the pixel 10 as illustrated in FIG. The height h ₅ from the surface of the first electrode layer 4.

The “cross section including the central portion of the flat organic layer” is the same as the “cross section including the central portion of the flat organic layer in the pixel” described in the first embodiment, and thus description thereof is omitted here.
The “length of the flat organic layer in the cross section including the central portion of the flat organic layer” is described in “the flat organic layer in the cross section including the central portion of the flat organic layer in the pixel” described in the first aspect. Since it is the same as “length”, the description here is omitted.

The “predetermined portion at a predetermined distance from the central portion” refers to a portion at a predetermined distance parallel to the substrate surface from the central portion of the flat organic layer. For example, as illustrated in FIG. 9 refers to the predetermined portion 22a, 22b that parallel in a predetermined distance d ₄ from the central portion 21 to the substrate 2 side of the flat organic layer (light emitting layer 7).
The “height from the surface of the first electrode layer at a predetermined distance from the central portion” means the central portion of the flat organic layer (light emitting layer 7) in the pixel 10 as illustrated in FIG. The heights h ₆ and h ₇ from the surface of the first electrode layer 4 of the predetermined portions 22a and 22b at a predetermined distance d ₄ from the line 21 are referred to.

  Here, the height of the central portion of the flat organic layer from the surface of the first electrode layer, and the height of the predetermined portion of the flat organic layer from the surface of the first electrode layer are as follows. Measured by scanning white light interferometry.

  In this aspect, in all of the pixels defined by the partition walls, the height of the central portion of the flat organic layer in the pixel from the surface of the first electrode layer and the flat organic layer in a cross section including the central portion of the flat organic layer. When the length is set to 1, the difference between the height from the surface of the first electrode layer at a predetermined distance from the center portion becomes a predetermined value or less.

In all pixels, the difference between the height of the central portion of the flat organic layer from the surface of the first electrode layer and the height of the predetermined portion of the flat organic layer from the surface of the first electrode layer is not more than a predetermined value. Can be confirmed as follows.
That is, among all the pixels, the above height difference is measured for each of the ten pixels in the central region and the ten pixels in the peripheral region. If the difference in height for the ten pixels in the central region and the difference in height for the ten pixels in the peripheral region are both equal to or less than a predetermined value, the above-described difference is found in all pixels. Is considered to be less than or equal to a predetermined value.

  Note that “pixels in the peripheral area” refers to pixels in three columns on the outer periphery among all the pixels. Further, the “pixel in the central region” refers to a pixel other than the pixels in the peripheral region. For example, as shown in FIG. 10, when circular pixels 10 are arranged, the pixels in the three outer peripheral columns are the pixels 10a in the peripheral region, and the other pixels are the pixels 10b in the central region.

  In this aspect, the difference between the height of the central portion of the flat organic layer from the surface of the first electrode layer and the height of the predetermined portion of the flat organic layer from the surface of the first electrode layer is not more than a predetermined value in all pixels. Therefore, the thickness of most of the flat organic layer in the pixel is uniform, and the shape of the flat organic layer is uniform in all pixels, thereby reducing luminance unevenness and color unevenness and improving display quality. It is possible.

  In addition, since the entire surface of the partition wall has liquid repellency, when an organic EL element is manufactured, the partition wall having lyophilicity and the partition wall having liquid repellency are laminated as in the past, or the side surface of the partition wall is There is no need to make it lyophilic and make the top surface liquid repellent, and the manufacturing process can be simplified.

  Note that the pixel, the first electrode layer, the second electrode layer, and the substrate are the same as those described in the first embodiment, and thus description thereof is omitted here. Hereinafter, another configuration of the organic EL element of this embodiment will be described.

(1) Organic EL layer The organic EL layer in this embodiment is formed on the first electrode layer and has one or more organic layers including a light emitting layer, and has a flat organic layer as the organic layer. is there.
Since points other than the flat organic layer in the organic EL layer are the same as those in the first aspect, description thereof is omitted here. Hereinafter, the flat organic layer will be described.

  In all of the pixels, the flat organic layer in this aspect includes the height of the central portion of the flat organic layer in the pixel from the surface of the first electrode layer and the length of the flat organic layer in a cross section including the central portion of the flat organic layer. The difference between the height from the surface of the first electrode layer at a predetermined portion at a distance of 0.25 from the center portion when 5 is 1 or less is 5 nm or less.

  The difference between the height of the central portion of the flat organic layer from the surface of the first electrode layer and the height of the predetermined portion of the flat organic layer from the surface of the first electrode layer is 5 nm or less, preferably 3 nm or less, more preferably 2 nm or less. This is because the display quality can be further improved if the height difference is within the above range. Since the difference in height is preferably as small as possible, the lower limit is not particularly limited.

  Note that when the flat organic layer is a light emitting layer, a hole transport layer, a hole injection layer, an electron transport layer, etc., each layer is the same as described in the first aspect, Description is omitted.

(2) Partition Wall The partition wall in this embodiment is formed between the first electrode layers on the substrate and has liquid repellency on the entire surface. Since the entire surface of the partition wall has liquid repellency, when the organic layer forming coating solution for forming the organic EL layer is discharged, the organic layer forming coating solution is applied to a predetermined region with high accuracy. be able to.
In addition, about the liquid repellency of a partition, a constituent material, thickness, a formation method, etc., since it is the same as that of what was described in the said 1st aspect, description here is abbreviate | omitted.

B. Next, a method for manufacturing the organic EL element of the present invention will be described.
The organic EL device manufacturing method of the present invention includes a solvent having an organic material and a surface tension of 40 mN / m or less on a substrate in which a first electrode layer is formed in a pattern and a partition wall is formed between the first electrode layers. A flat organic layer is formed by applying a coating solution for forming a flat organic layer containing the above by a discharge method and drying the solvent so that the evaporation rate of the solvent is 1.0 × 10 ⁻³ μl / sec or more. And a flat organic layer forming step.

The manufacturing method of the organic EL element of this invention is demonstrated referring drawings.
FIG. 11 is a process diagram showing an example of a method for producing an organic EL element of the present invention.
First, although not shown, a partition wall-forming coating solution is applied onto a substrate on which a first electrode layer is formed in a pattern, exposed and developed, and a partition wall 5 is formed between the first electrode layers 4 on the substrate 2. This is formed (FIG. 11A). Next, on the first electrode layer 4, a hole injection layer forming coating solution 6 ′ is discharged from the inkjet head 31 and dried to form the hole injection layer 6 (FIGS. 11B and 11B). c), hole injection layer forming step). Next, a light emitting layer forming coating solution 7 ′ containing a light emitting material and a solvent having a predetermined surface tension is discharged from the inkjet head 32 and dried to form the light emitting layer 7 (FIGS. 11D and 11E). ), Light emitting layer forming step). When the applied light emitting layer forming coating solution is dried, it is dried so that the evaporation rate of the solvent in the light emitting layer forming coating solution is equal to or higher than a predetermined value. Next, the 2nd electrode layer 9 is formed on the organic electroluminescent layer 8 comprised from the positive hole injection layer 6 and the light emitting layer 7 (FIG.11 (g), 2nd electrode layer formation process). In FIG. 11, the light emitting layer forming step shown in FIGS. 11D and 11E is a flat organic layer forming step.

  Conventionally, among all the pixels 10 illustrated in FIG. 10, there is a case where a difference occurs in the film thickness of the organic layer between the pixel 10 a in the peripheral region, particularly the outermost pixel and the pixel 10 b in the central region. . This is due to the following reason. That is, since the organic layer forming coating solution is not applied to the outer periphery of the outermost peripheral pixel in the peripheral region pixel 10a, particularly the outermost peripheral pixel, the partial pressure of the solvent molecules in the organic layer forming coating solution is This is lower than the partial pressure of the solvent molecules in the organic layer forming coating solution at the pixel 10b in the central region. Therefore, in the pixel 10a in the peripheral region, particularly the pixel in the outermost periphery, the solvent in the organic layer forming coating liquid dries faster than the pixel 10b in the central region. As a result, for example, as shown in FIG. 12, there is a difference in the film thickness of the organic layer 107 between the pixel 10a in the peripheral region and the pixel 10b in the central region.

  In general, the difference in the partial pressure of solvent molecules in the coating liquid for forming an organic layer causes a difference in the film thickness of the organic layer between the peripheral region pixel and the central region pixel. The solvent used for the layer forming coating solution has a relatively high boiling point and a relatively low evaporation rate of the solvent. Since the evaporation rate of the solvent is relatively slow, a difference occurs in the evaporation rate of the solvent between the peripheral region pixel and the central region pixel, resulting in a difference in the film thickness of the organic layer.

  Therefore, as a result of extensive research, the present inventor has used a solvent having a relatively low boiling point and a relatively high evaporation rate of the solvent in order to uniformly dry the applied organic layer forming coating solution. The present inventors have found that it is desirable to immediately dry the applied organic layer forming coating solution. In addition, since the surface tension is related to the cross-sectional shape of the applied organic layer forming coating solution and the wettability of the layer surface to which the organic layer forming coating solution is applied, attention was also paid to the surface tension. .

  According to the present invention, the coating liquid for forming a flat organic layer containing an organic material and a solvent having a predetermined surface tension is applied by a discharge method and dried so that the evaporation rate of the solvent becomes a predetermined value or more. , The solvent in the applied coating liquid for forming a flat organic layer can be immediately dried, and most of the film thickness in the pixel is uniform, and a flat organic layer having a uniform shape in all pixels is formed. can do. Therefore, it is possible to obtain an organic EL element with high display quality that does not have uneven luminance and uneven color.

In addition, as in the past, in order to uniformly dry the applied organic layer forming coating solution, it can be dried in a solvent atmosphere, or a member for the solvent atmosphere can be separately formed, It is not necessary to apply an organic layer forming coating solution or solvent to the outer periphery of the pixel, and the manufacturing process can be simplified.
Hereinafter, each process of the manufacturing method of the organic EL element of this invention is demonstrated.

1. Flat organic layer forming step In the flat organic layer forming step in the present invention, an organic material and a surface tension of 40 mN / m are formed on a substrate on which a first electrode layer is formed in a pattern and a partition wall is formed between the first electrode layers. A coating liquid for forming a flat organic layer containing the following solvent is applied by a discharge method and dried so that the evaporation rate of the solvent is 1.0 × 10 ⁻³ μl / sec or more. This is a step of forming an organic layer.

  The coating solution for forming a flat organic layer can be prepared by dissolving or dispersing an organic material in a solvent having a predetermined surface tension.

  The surface tension of the solvent used for the coating liquid for forming a flat organic layer is 40 mN / m or less, preferably 36 mN / m or less, more preferably 29 mN / m or less. This is because the lower the surface tension of the solvent, the easier it is to evaporate. Therefore, the lower limit of the surface tension of the solvent is not particularly limited.

  Further, the boiling point of the solvent is preferably 250 ° C. or lower, more preferably 200 ° C. or lower, and further preferably 150 ° C. or lower. This is because the lower the boiling point of the solvent, the easier it is to evaporate under conditions where heating is not performed and the evaporation rate of the solvent is not changed. Therefore, the lower limit of the boiling point of the solvent is not particularly limited.

  Examples of such a solvent include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohols such as methanol, ethanol, 2-propanol, n-butanol, and 2-ethoxyethanol; benzene, toluene, xylene, Aromatic hydrocarbons such as mesitylene, p-cymene and diisopropylbenzene; esters such as ethyl acetate, isobutyl acetate, butyl acetate and methyl propionate; diethyl ether, diisopropyl ether, tert-butyl methyl ether, cyclopentyl methyl ether, dimethoxy Ethers such as ethane, ethylene glycol diethyl ether, tetrahydrofuran, 1,4-dioxane; pentane, hexane, heptane, octane, decane, dodecane, undecane Cyclohexane, aliphatic hydrocarbons decalin; dichloromethane, 1,2-dichloroethane, chloroform, o- halogenated aromatic hydrocarbons dichlorobenzene, and the like. Of these, aromatic hydrocarbons are preferable, and toluene and xylene are particularly preferable. This is because toluene and xylene have relatively low surface tension and boiling point. Therefore, for example, the evaporation rate can be set within a predetermined range under moderate conditions such as normal temperature and normal pressure.

  In addition, since it described in detail in the term of the flat organic layer of said "A. organic EL element" about the organic material, description here is abbreviate | omitted.

  The application method of the coating liquid for forming a flat organic layer may be a discharge method, and examples thereof include an inkjet method and a dispenser method.

  In order to more uniformly dry the flat organic layer forming coating solution between the peripheral region pixels and the central region pixels, it is preferable that the discharge intervals of the flat organic layer forming coating solution are equal. When the pixel pitch is equal in both the X direction and the Y direction, the flat organic layer forming coating solution may be ejected at equal intervals in either the X direction or the Y direction. In addition, the pixel pitch is equal in the X direction and equal in the Y direction, but when the interval is different between the X direction and the Y direction, it is dried quickly, It is preferable to discharge the coating liquid for forming a flat organic layer at regular intervals. Furthermore, when the pixel shape is a rectangle, a track shape, or the like and the pixels are arranged at different pitches in the X direction and the Y direction, a flat organic layer is formed in a wider direction in the pixel. The coating liquid may be discharged at regular intervals.

  Further, the method for drying the applied coating liquid for forming a flat organic layer is not particularly limited as long as the evaporation rate of the solvent can be within a predetermined range, and a general drying method can be used. Examples thereof include natural drying, air drying, heat drying, and reduced pressure drying.

The evaporation rate of the solvent at this time is set to 1.0 × 10 ⁻³ μl / sec or more, preferably 1.5 × 10 ⁻³ μl / sec or more, more preferably 2.0 × 10 ⁻³ μl / sec or more. If the evaporation rate of the solvent is within the above range, the thickness of the flat organic layer can be made uniform. On the other hand, the upper limit of the evaporation rate of the solvent is about 1.0 × 10 ⁻¹ μl / sec. This is because if the evaporation rate of the solvent is too high, the discharged flat organic layer forming coating solution may solidify before spreading and it may be difficult to obtain a flat organic layer having a uniform film thickness.

  The evaporation rate of the solvent can be obtained by a method of measuring the time for completely evaporating the solvent by dropping 1 μl of the solvent onto the substrate at a temperature of 23 ° C.

  The atmosphere for drying the coating liquid for forming a flat organic layer is not particularly limited as long as the evaporation rate of the solvent can be within a predetermined range. For example, the atmosphere is a vacuum atmosphere, an inert gas such as nitrogen gas, etc. It can be an atmosphere, an air atmosphere, or the like. When the organic material in the coating liquid for forming a flat organic layer is deteriorated by oxygen, water, or the like, a vacuum atmosphere or an inert gas atmosphere is preferable.

  Since the other points of the flat organic layer are described in the section of the flat organic layer in the above “A. Organic EL element”, description thereof is omitted here.

2. Other Steps The method for producing an organic EL device of the present invention may have other steps in addition to the flat organic layer forming step. Usually, an organic EL layer forming step for forming a flat organic layer and forming an organic EL layer including the flat organic layer is performed. Moreover, the partition formation process which forms a partition on the board | substrate with which the 1st electrode layer was formed in the pattern form, the 2nd electrode layer formation process which forms a 2nd electrode layer on an organic EL layer, etc. can be performed.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be specifically described using examples and comparative examples.

[Example 1]
A transparent electrode made of ITO was formed in a pattern on a glass substrate. Next, a liquid repellent material containing a fluorine-containing resin, a photoacid generator, an acid cross-linking agent and an alkali-soluble resin is applied onto the substrate so as to partition this transparent electrode, exposed and developed, and a partition wall having a thickness of 2 μm. Formed. The pixels defined by the partition walls were circular with a diameter of 70 μm.

  Next, an aqueous dispersion of PEDOT was ejected from the inkjet head at a pitch of 100 μm in the X direction and a pitch of 200 μm in the Y direction in a region separated by the partition walls. Thereafter, the substrate coated with PEDOT was placed in a glove box and heated at 200 ° C. for 10 minutes in a nitrogen atmosphere. Thereby, a hole injection layer was formed.

Next, thermosetting with bis (N- (1-naphthyl-N-phenyl) benzidine) (α-NPD) and 4,4'-bis (2,2-diphenyl-ethen-1-yl) diphenyl (DPVBi) The xylene solution mixed with the conductive epoxy resin composition at a weight ratio of 7: 3: 7 was discharged from the inkjet head at a pitch of 100 μm in both the X direction and the Y direction. After waiting for the xylene to evaporate by natural drying, it was heated in a glove box at 200 ° C. for 1 hour. Thereby, a hole transport layer was formed.
The thermosetting epoxy resin composition is a liquid type hydrogenated bisphenol A type epoxy resin (Asahi Denka Kogyo, Adeka Resin EP-4080S) added with phthalic anhydride as a curing agent (epoxy resin: Phthalic anhydride = 10: 1 (weight ratio)) was used.
Furthermore, xylene has a boiling point of 139.1 ° C. and a surface tension of 28.1 mN / m. Further, the evaporation rate of xylene during natural drying was 2.4 × 10 ⁻³ μl / sec.

  About the obtained hole transport layer, the height from the 1st electrode layer surface was measured by the above-mentioned method. In the cross section including the central portion of the hole transport layer in the pixel, the length of the hole transport layer was 80 μm, and the length of the flat portion of the hole transport layer was 50 μm. Further, in the cross section including the central portion of the hole transport layer in the pixel, the height of the central portion of the hole transport layer from the surface of the first electrode layer is 100 nm, and the first electrode of the predetermined portion of the hole transport layer The height from the layer surface was 103 nm.

Next, 2-Methyl-9,10-bis (naphthalen-2-yl) anthracene (LT-E410 manufactured by Aujek) and 4,4'-Bis [4- (di-p-tolylamino) styryl] biphenyl (Auigek) A toluene solution mixed with a LT-E605 (made by company) at a weight ratio of 20: 1 was discharged from an inkjet head at a pitch of 100 μm in both the X and Y directions. After waiting for toluene to evaporate by natural drying, it was heated in a glove box at 90 ° C. for 1 hour. This formed the light emitting layer.
In addition, toluene has a boiling point of 110.6 ° C. and a surface tension of 28.4 mN / m. Further, the evaporation rate of toluene during natural drying was 7.8 × 10 ⁻³ μl / sec.

  About the obtained light emitting layer, the height from the 1st electrode layer surface was measured by the above-mentioned method. In the cross section including the central portion of the light emitting layer in the pixel, the length of the light emitting layer was 70 μm, and the length of the flat portion of the light emitting layer was 50 μm. In the cross section including the central portion of the light emitting layer in the pixel, the height of the central portion of the light emitting layer from the surface of the first electrode layer is 130 nm, and the height of the predetermined portion of the light emitting layer from the surface of the first electrode layer. Was 133 nm.

Next, on the light-emitting layer, Alq ₃ having a thickness of 20 nm as an electron transport layer, LiF having a thickness of 0.5 nm as an electron injection layer, and Al having a thickness of 250 nm as a cathode were laminated and formed by a vacuum heating deposition method. Then, the epoxy resin was apply | coated around the sealing board, this sealing board was put on the glass substrate, the epoxy resin was hardened by irradiating an ultraviolet-ray, and sealing was performed.

  The obtained organic EL device had a light emitting area of 2 mm square in which circular pixels with a diameter of 70 μm were arranged at a pitch of 100 μm in both the X direction and the Y direction. With this organic EL element, uniform display without uneven brightness and uneven color was obtained.

[Comparative Example 1]
In the same manner as in Example 1, a transparent electrode, a partition wall and a hole injection layer were formed on a glass substrate.
Next, a hole transport layer was formed in the same manner as in Example 1 except that the solvent was changed from xylene to butylbenzene.
Subsequently, the light emitting layer was formed like Example 1 except having changed the solvent from toluene into butylbenzene.
Butylbenzene has a boiling point of 183 ° C. and a surface tension of 29 mN / m. Further, the evaporation rate of butylbenzene during natural drying was 3.3 × 10 ⁻⁴ μl / sec.

  About the obtained light emitting layer, the height from the 1st electrode layer surface was measured by the above-mentioned method. In the cross section including the central portion of the light emitting layer in the pixel, the length of the light emitting layer was 70 μm, and the length of the flat portion of the light emitting layer was 27 μm. In the cross section including the central portion of the light emitting layer in the pixel, the height of the central portion of the light emitting layer from the surface of the first electrode layer is 150 nm, and the height of the predetermined portion of the light emitting layer from the surface of the first electrode layer. Was 160 nm.

Next, on the light-emitting layer, Alq ₃ having a thickness of 20 nm as an electron transport layer, LiF having a thickness of 0.5 nm as an electron injection layer, and Al having a thickness of 250 nm as a cathode were laminated and formed by a vacuum heating deposition method. Then, the epoxy resin was apply | coated around the sealing board, this sealing board was put on the glass substrate, the epoxy resin was hardened by irradiating an ultraviolet-ray, and sealing was performed.

  The obtained organic EL device had a light emitting area of 2 mm square in which circular pixels with a diameter of 70 μm were arranged at a pitch of 100 μm in both the X direction and the Y direction. In this organic EL element, film thickness unevenness, luminance unevenness, and color unevenness were observed.

[Reference Example 1]
In the same manner as in Example 1, transparent electrodes and partition walls were formed on a glass substrate. The pixels defined by the partition walls were circular with a diameter of 70 μm. Further, as illustrated in FIG. 14A, four regions A, B, C, and D in which the pixels 10 are arranged in the same manner are provided on the substrate. FIG. 14B is an enlarged view of each region A, B, C, D of FIG.

Next, a light emitting layer was formed in the region separated by the partition walls in the same manner as in Example 1. At this time, a light emitting layer was directly formed on the transparent electrode.
FIG. 13 shows the thickness of the light emitting layer (height of the light emitting layer from the surface of the transparent electrode).
Further, the film thickness of the light emitting layer was measured for the pixels at positions I, II, III, IV, and V in the respective regions A, B, C, and D as illustrated in FIG. FIG. 15 shows the measurement results of the film thickness of the light emitting layer with respect to the pixel at the position IV in the area B, the position I in the area D, the position III in the area D, and the position IV in the area D. In FIG. 15, the partition wall indicates a state before the light emitting layer is formed. When toluene was used, the film was dried immediately after discharge, so that the thickness of the light emitting layer was not uneven depending on the location in the same substrate.

[Reference Example 2]
A light emitting layer was formed in the same manner as in Reference Example 1 except that xylene was used instead of toluene. The evaporation rate of xylene during natural drying was 2.43 × 10 ⁻³ μl / sec.
The film thickness of the light emitting layer (height of the light emitting layer from the transparent electrode surface) is shown in FIG.

[Reference Example 3]
A light emitting layer was formed in the same manner as in Reference Example 1 except that anisole (surface tension 35 mN / m, boiling point 155 ° C.) was used instead of toluene. The evaporation rate of anisole during natural drying was 9.31 × 10 ⁻⁴ μl / sec.
FIG. 17 shows the thickness of the light emitting layer (height of the light emitting layer from the surface of the transparent electrode).

[Reference Example 4]
A light emitting layer was formed in the same manner as in Reference Example 1 except that mesitylene (surface tension 28.3 mN / m, boiling point 164.7 ° C.) was used instead of toluene. The evaporation rate of mesitylene during natural drying was 6.68 × 10 ⁻⁴ μl / sec.
The film thickness of the light emitting layer (the height of the light emitting layer from the transparent electrode surface) is shown in FIG.

[Reference Example 5]
A light emitting layer was formed in the same manner as in Reference Example 1 except that butylbenzene was used instead of toluene. The evaporation rate of butylbenzene during natural drying was 3.31 × 10 ⁻⁴ μl / sec.
The film thickness of the light emitting layer (height of the light emitting layer from the transparent electrode surface) is shown in FIG.

It is a schematic sectional drawing which shows an example of the organic EL element of this invention. It is a graph which shows the film thickness of the light emitting layer in a pixel. It is a schematic diagram which shows a pixel. It is a schematic diagram for demonstrating a flat organic layer. It is a schematic diagram for demonstrating the conventional organic layer. It is a schematic sectional drawing which shows the other example of the organic EL element of this invention. It is a schematic sectional drawing which shows the other example of the organic EL element of this invention. It is a schematic sectional drawing which shows the other example of the organic EL element of this invention. It is a schematic diagram for demonstrating a flat organic layer. It is a schematic diagram which shows a pixel. It is process drawing which shows an example of the manufacturing method of the organic EL element of this invention. It is a schematic diagram for demonstrating the conventional organic layer. 10 is a graph showing the film thickness of the light emitting layer in the pixel of Reference Example 1. It is a schematic diagram which shows a pixel. 10 is a graph showing the film thickness of the light emitting layer in the pixel of Reference Example 1. 10 is a graph showing the thickness of the light emitting layer in the pixel of Reference Example 2. 10 is a graph showing the film thickness of a light emitting layer in a pixel of Reference Example 3. 10 is a graph showing the film thickness of a light emitting layer in a pixel of Reference Example 4. 10 is a graph showing the film thickness of a light emitting layer in a pixel of Reference Example 5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Organic EL element 2 ... Board | substrate 4 ... 1st electrode layer 5 ... Partition 6 ... Hole injection layer 7 ... Light emitting layer 8 ... Organic EL layer 9 ... 2nd electrode layer 10 ... Pixel 11 ... Flat part 12 ... Peripheral part 17 … Flat organic layer

Claims (7)

1 including a substrate, a first electrode layer formed in a pattern on the substrate, a partition formed between the first electrode layers on the substrate, and a light emitting layer formed on the first electrode layer. An organic electroluminescence device having an organic electroluminescence layer having an organic layer of at least one layer and a second electrode layer formed on the organic electroluminescence layer,
The organic electroluminescence layer has a flat organic layer as the organic layer,
In the pixel defined by the partition wall, the flat organic layer has a flat portion and a peripheral portion disposed around the flat portion, and the cross section includes a central portion of the flat organic layer in the pixel. When the length of the flat organic layer is 1, the length of the flat portion is 0.7 or more, and the cross-sectional shape of the flat organic layer in the pixel has an inflection point in the peripheral portion. An organic electroluminescence device characterized in that there is.   The organic electroluminescence device according to claim 1, wherein at least a part of the partition wall surface has liquid repellency. A substrate, a first electrode layer formed in a pattern on the substrate, a partition wall formed between the first electrode layers on the substrate and having liquid repellency on the entire surface, and on the first electrode layer An organic electroluminescence device comprising an organic electroluminescence layer formed and having one or more organic layers including a light emitting layer, and a second electrode layer formed on the organic electroluminescence layer,
The organic electroluminescence layer has a flat organic layer as the organic layer,
In all of the pixels defined by the partition walls, the flat organic layer in a cross section including the height of the central portion of the flat organic layer in the pixel from the surface of the first electrode layer and the central portion of the flat organic layer. An organic electroluminescence device, wherein a difference between a height of a predetermined portion at a distance of 0.25 from the center portion and the surface of the first electrode layer is 5 nm or less when the length of the electroluminescent device is 1.   The organic electroluminescence device according to any one of claims 1 to 3, wherein the flat organic layer is the light emitting layer. A flat organic layer forming coating containing an organic material and a solvent having a surface tension of 40 mN / m or less on a substrate on which a first electrode layer is formed in a pattern and a partition wall is formed between the first electrode layers. A flat organic layer forming step of forming a flat organic layer by applying a liquid by a discharge method and drying the solvent so that an evaporation rate of the solvent becomes 1.0 × 10 ⁻³ μl / sec or more; A method for producing an organic electroluminescent element.   6. The method of manufacturing an organic electroluminescence element according to claim 5, wherein at least a part of the surface of the partition wall has liquid repellency.   The method for producing an organic electroluminescent element according to claim 5, wherein the flat organic layer is a light emitting layer.

Images