JP7330779B2 - Organic EL device and its manufacturing method - Google Patents

Description

The present invention relates to an organic EL device and its manufacturing method.

An organic EL (electroluminescence) device is a device including a light-emitting element utilizing electroluminescence of an organic compound.
Japanese Patent Laying-Open No. 2007-035347 (Patent Document 1) describes an electroluminescence element in which a liquid-repellent partition (bank) is provided on a substrate and a functional layer is formed in a region partitioned by the partition. .

JP 2007-035347 A

In a surface-emitting organic EL device in which a light-emitting region is defined by a bank, unevenness in luminance may occur within the light-emitting region.
SUMMARY OF THE INVENTION It is an object of the present invention to provide an organic EL device having a light emitting region with reduced unevenness in light emission luminance.

The present invention provides an organic EL device and an organic EL device manufacturing method described below.
[1] An organic EL device having a light emitting region,
a substrate;
a bank having a thickness and a width disposed on the substrate so as to surround the light emitting region;
an organic layer structure;
including
The organic layer structure portion has a portion (A) disposed within the light emitting region and a portion (B) disposed above the bank and having a length _LB in the width direction of the bank. death,
The organic layer structure portion has the following formula, where _TAS is the maximum thickness in the portion (A) and _TAC is the central thickness in the portion (A):
T _AS /T _AC ≤1.1
An organic EL device comprising a portion that satisfies
[2] The organic EL device according to [1], wherein the maximum film thickness _TBS in the portion (B) is greater than the central film thickness _TAC in the portion (A).
[3] The organic EL device according to [1] or [2], wherein all edges of the organic layer structure are located on the bank.
[4] The organic EL device according to any one of [1] to [3], wherein the L _B is 2.5 mm or more.
[5] The organic EL device according to any one of [1] to [4], wherein the organic layer structure portion is composed of two or more organic layers.
[6] The organic layer structure section includes a first organic layer and a second organic layer disposed on the first organic layer,
The first organic layer has a portion (A1) arranged within the light emitting region and a portion (B1) arranged above the bank and having a length L _B1 in the width direction of the bank. death,
The second organic layer has a portion (A2) arranged within the light emitting region and a portion (B2) arranged above the bank and having a length _LB2 in the width direction of the bank. death,
The organic EL device of [5], wherein said _LB2 is the same as or greater than said _LB1 .
[7] The organic EL device according to any one of [1] to [6], wherein at least the upper surface of the bank has liquid repellency.
[8] The organic EL device according to any one of [1] to [7], wherein the bank has a single layer structure.
[9] The organic EL device according to any one of [1] to [8], wherein the light emitting region has a rectangular shape with at least one side having a length of 1 mm or more.
[10] A method for manufacturing an organic EL device having a light emitting region, comprising:
forming on a substrate a bank having a thickness and a width for defining the light emitting region;
controlling the liquid repellency of at least the upper surface of the bank;
a step of forming an organic layer structure by a coating method on the substrate on which the bank is formed;
including
The organic layer structure has a portion (A) arranged within the light emitting region and a portion (B) having a length _LB in the width direction of the bank and arranged above the bank. In addition, when the maximum film thickness at the portion (A) is T _AS and the central film thickness at the portion (A) is _TAC , the following formula:
T _AS /T _AC ≤1.1
A method of manufacturing an organic EL device formed to include a portion that satisfies
[11] The organic layer structure according to [10], wherein the organic layer structure portion is formed such that the maximum thickness _TBS in the portion (B) is larger than the central thickness _TAC in the portion (A). A method for manufacturing an EL device.
[12] The method for manufacturing an organic EL device according to [10] or [11], wherein the organic layer structure portion is formed so that the _LB is 2.5 mm or more.
[13] The method for manufacturing an organic EL device according to any one of [10] to [12], wherein the organic layer structure portion is composed of two or more organic layers.
[14] The step of forming the organic layer structure includes
a step of applying a coating liquid for forming a first organic layer on the substrate on which the banks are formed to form a first coating film;
drying the first coating film to form a first organic layer;
a step of applying a coating liquid for forming a second organic layer on the first organic layer to form a second coating film;
drying the second coating film to form a second organic layer;
including
The first organic layer has a portion (A1) arranged within the light emitting region and a portion (B1) arranged above the bank and having a length L _B1 in the width direction of the bank. is formed as
The second organic layer has a portion (A2) arranged within the light emitting region and a portion (B2) arranged above the bank and having a length _LB2 in the width direction of the bank. , and the _LB2 is formed to be the same as or larger than the _LB1 .
[15] The steps of [10] to [14], wherein the step of controlling the liquid repellency includes a step of setting the contact angle of at least the upper surface of the bank with respect to the coating liquid for forming the first organic layer to less than 10 degrees. A method for manufacturing an organic EL device according to any one of the above.

It is possible to provide an organic EL device having a light emitting region with reduced unevenness in light emission luminance.

1 is a schematic plan view showing an example of a banked substrate that an organic EL device according to the present invention can have; FIG. FIG. 2 is a schematic cross-sectional view showing a partially enlarged bank periphery in an example of the organic EL device according to the present invention; FIG. 4 is a schematic cross-sectional view showing a partially enlarged bank periphery in another example of the organic EL device according to the present invention;

Hereinafter, the present invention will be described while showing embodiments. The same reference numerals are given to the same elements. Redundant explanations are omitted. The dimensional proportions in the drawings may not necessarily match those in the description.

<Organic EL device>
An organic EL device according to the present invention (hereinafter also simply referred to as an "organic EL device") includes a substrate, a bank arranged on the substrate, and an organic layer structure. The bank defines the light emitting region of the organic EL device and is arranged on the substrate so as to surround the light emitting region. The light-emitting region of the organic EL device means the area surrounded by the banks, among the two-dimensional areas that emit light when voltage is applied.
The organic EL device may have only one light-emitting region, or may have two or more light-emitting regions.
For example, two or more light emitting regions may be arranged in a two-dimensional array (or matrix) on the substrate. The spacing between the light-emitting regions in each column, the spacing between the light-emitting regions in each row, the arrangement example of the light-emitting regions, the number of light-emitting regions, and the like are appropriately set according to the specifications of the organic EL device.
The organic EL device may be a top emission type device or a bottom emission type device.

A light-emitting region of the organic EL device is provided with a light-emitting portion, which is a structural portion for causing light emission. The light-emitting portion includes at least a first electrode (eg, anode), an organic layer structure, and a second electrode (eg, cathode) in order from the substrate side. The organic layer structure part is composed of organic layers, and may include one or more organic layers. The organic layer structure is a layer that contributes to light emission of the organic EL device.

The structure of the organic EL device and the constituent elements of the organic EL device will be described in more detail.

(1) Substrate FIG. 1 is a schematic plan view showing an example of a banked substrate that an organic EL device according to the present invention can have. The banked substrate 10 shown in FIG. 1 has a substrate 11 , a first electrode 12 (eg, an anode), and a bank 13 .
The substrate 11 is a support that supports the first electrodes 12 and the banks 13, and is, for example, a plate-like transparent member that transmits visible light (light with a wavelength of 400 nm to 800 nm).
The thickness of the substrate 11 is, for example, 30 μm or more and 1100 μm or less. The substrate 11 may be, for example, a rigid substrate such as a glass substrate or a silicon substrate, or a flexible substrate such as a plastic substrate or a polymer film. By using a flexible substrate, the organic EL device can have flexibility.

A circuit for driving the light emitting unit may be formed in advance on the substrate 11 . For example, a TFT (Thin Film Transistor), a capacitor, or the like may be formed in advance on the substrate 11 .

(2) First Electrode The first electrode 12 is, for example, an anode. However, the first electrode 12 may be the cathode and the second electrode may be the anode.
The shape of the first electrode 12 in a plan view (the shape viewed from the thickness direction of the substrate 11) may be, for example, a rectangle, a square such as a square, other polygons, and a rectangle or other polygon with rounded corners. and the like. The planar shape of the first electrode 12 may be circular or elliptical. The planar shape of the first electrode 12 may be a quadrangle or other polygon with at least one side arcuate (for example, arcuate).
In this specification, "planar view" means viewing from the thickness direction of a layer or the like.

The first electrode 12 can use a thin film made of metal oxide, metal sulfide, metal, or the like. Specifically, indium oxide, zinc oxide, tin oxide, indium tin oxide (abbreviated as ITO ), Indium Zinc Oxide (abbreviated as IZO), gold, platinum, silver, or copper.
When the organic EL device emits light from the substrate 11 side, the first electrode 12 exhibiting optical transparency is used.

The thickness of the first electrode 12 can be appropriately determined in consideration of light transmittance, electrical conductivity, and the like. The thickness of the first electrode 12 is, for example, 10 nm or more and 10 μm or less, preferably 20 nm or more and 1 μm or less, and more preferably 50 nm or more and 500 nm or less.

In one embodiment, a layer composed of an insulating layer or the like may be provided between the first electrode 12 and the substrate 11 . A layer composed of an insulating layer or the like can also be regarded as part of the substrate 11 .

(3) Bank The bank 13 is a partition wall having a thickness and width for defining the light emitting region 14 of the organic EL device. be. The bank 13 is arranged on the substrate 11 , more specifically on the first electrode 12 formed on the substrate 11 . At this time, from the viewpoint of preventing a short circuit between the first electrode 12 and the second electrode, as shown in FIG. preferably.

The banks 13 are provided on the substrate 11 in a pattern having openings to define light emitting regions 14 that are preset on the surface of the substrate 11 .
In the example shown in FIG. 1, the bank 13 has a square frame shape in plan view, but the opening shape and outer shape of the bank 13 (both plan view shapes) are not limited to this. is appropriately selected according to the desired shape of the light emitting region 14 and the shape of the substrate 11 (both are planar view shapes).
The shape of the opening of the bank 13 (that is, the shape of the light emitting region 14) is usually 1 mm ² or more, preferably 5 mm ² or more, and usually 1 m ² or less.
In one embodiment, the shape of the opening of the bank 13 (that is, the shape of the light emitting region 14) is, as shown in FIG. It is 1 mm or more, and two or more sides or all sides may have a length of 1 mm or more. The length of the side may be 5 mm or longer, 10 mm or longer, or 20 mm or longer. When the bank 13 has a rectangular opening, the length of one side is usually 1000 mm or less.
The larger the area of the light-emitting region 14, the easier it is for the unevenness of the light emission brightness to be visually recognized. is particularly advantageous for

The bank 13 can be composed of, for example, one or more resin compositions.
When an organic layer such as a first organic layer constituting the organic layer structure is formed by a coating method to be described later, the bank 13 is provided from the viewpoint that the light emitting region 14 can be preferably defined (divided) by the bank. From the viewpoint of preventing the organic layer from wetting and spreading to the outside of 13, preferably at least its upper surface (the surface opposite to substrate 11) has liquid repellency, and more preferably its upper surface and Its side surface has liquid repellency.
The fact that at least the top surface of the bank 13 has liquid repellency suppresses uneven contraction of the coating film in the drying process of heating the coating film formed in contact with at least the top surface of the bank 13 to form an organic layer. It is also advantageous for
The term "liquid repellency" as used herein means repellency to a coating liquid for forming an organic layer used in a coating method. The organic layer in the "liquid repellency to the coating liquid for forming the organic layer" is usually the first organic layer formed on the first electrode 12 (the organic layer closest to the first electrode 12), that is, the first organic layer is.

As the bank 13 having at least the liquid repellent upper surface, a layer made of a thermoplastic resin composition containing a liquid repellent agent, a layer made of a cured photosensitive resin composition containing a liquid repellent agent, or a thermosetting resin composition containing a liquid repellent agent. At least the upper surface of a bank that is a layer made of a cured product of a curable resin composition, a layer made of a thermoplastic resin, a layer made of a cured product of a photosensitive resin composition, a layer made of a cured product of a thermosetting resin composition, etc. A bank or the like obtained by applying a liquid-repellent treatment to the substrate is exemplified.
Examples of the liquid-repellent treatment include a treatment of applying a liquid-repellent agent containing a fluorine resin or the like, and a treatment of irradiating the coated surface with an active energy ray such as ultraviolet rays after applying the liquid-repellent agent.
The liquid repellency of at least the upper surface of the bank 13 may be controlled by UV ozone treatment.
On at least the upper surface of a layer made of a thermoplastic resin composition containing a liquid repellent agent, a layer made of a cured photosensitive resin composition containing a liquid repellent agent, or a layer made of a cured thermosetting resin composition containing a liquid repellent agent The liquid-repellent treatment may be further applied.

The contact angle of the upper surface of the bank 13 with respect to the coating liquid is preferably less than 10 degrees, which is more advantageous in providing an organic EL device having a light emitting region with reduced unevenness in light emission luminance. degree or less, and more preferably less than 8 degrees. For the same reason, the contact angle of the side surface of the bank 13 with respect to the coating liquid is preferably less than 10 degrees, more preferably 9 degrees or less, and even more preferably less than 8 degrees.
The contact angle is measured according to the method described in [Examples] below.

The bank 13 may have a single-layer structure, or may have a multi-layer structure in which two or more layers are laminated in the thickness direction. The bank 13 is preferably a single layer structure because it is easier to fabricate the bank 13 .

The cross-sectional shape of the bank 13 is not particularly limited. For example, the side surface of the bank 13 facing the light emitting region 14 may be perpendicular to the surface of the substrate 11 or may be inclined at an acute angle. (forward taper type).

The thickness (height) of the bank 13 is, for example, about 0.3 μm or more and 10 μm or less, preferably 0.5 μm or more and 5 μm or less.
The width of the bank 13 (W shown in FIG. 1) is, for example, about 0.5 mm or more and 20 mm or less, preferably 1 mm or more and 10 mm or less.
When the outer shape (planar view) of the bank 13 is rectangular, the length of one side thereof is, for example, about 0.5 mm or more and 1000 mm or less, preferably about 1 mm or more and 1000 mm or less.

The banked substrate 10 can be manufactured, for example, by forming the bank 13 after forming the first electrode 12 on the light-emitting region 14 preset on the substrate 11 .

The bank 13 can be formed using, for example, a coating method. Specifically, the coating film obtained by applying the coating liquid containing the material of the bank 13 to the substrate 11 on which the first electrodes 12 are formed is dried, and after performing a curing treatment as necessary, the coating film is dried. can be formed by patterning into a predetermined shape. Examples of coating methods include a spin coating method and a slit coating method. The solvent of the coating liquid containing the material of the bank 13 may be any solvent that can dissolve the material of the bank 13 .

Further, the bank 13 is formed by forming a patterned coating film by, for example, an inkjet coating method, a screen printing method, a gravure printing method, a flexographic printing method, a dispenser coating method, a nozzle coating method, or the like, and a hardening treatment is performed as necessary. It can also be formed by a drawing method.

(4) Organic layer structure part As described above, a light emitting part is provided in the light emitting region of the organic EL device, and the light emitting part includes at least the first electrode (eg, anode), the organic layer structure part, electrodes (eg, cathodes); Between the first electrode and the second electrode, the organic layer structure portion is composed of an organic layer, and may include one or more organic layers, and usually two or more organic layers. be provided.
In this specification, the first organic layer means an organic layer first formed on the first electrode 12 (the organic layer closest to the first electrode 12). The first organic layer is preferably a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer or an electron injection layer, more preferably a hole injection layer or a light emitting layer, still more preferably a hole injection layer. layer.

When the first organic layer is a hole injection layer, an electron transport layer, or an electron injection layer, the light emitting section further has at least a light emitting layer as an organic layer other than the first organic layer.
When the first organic layer is a light-emitting layer, the light-emitting part may have only the first organic layer as the organic layer, but preferably further includes other organic layers.

The hole injection layer is an organic layer that has the function of improving the efficiency of hole injection from the anode (eg, first electrode 12) to the light emitting layer.
A known hole injection material can be used for the material of the hole injection layer. Examples of hole injection materials include oxides such as vanadium oxide, molybdenum oxide, ruthenium oxide and aluminum oxide; phenylamine compounds; starburst type amine compounds; phthalocyanine compounds; and polythiophene derivatives such as

A light-emitting layer is an organic layer having a function of emitting light of a predetermined wavelength.
The light-emitting layer is usually formed of an organic material that mainly emits fluorescence and/or phosphorescence, or the organic material and a dopant that assists this. A dopant is added, for example, to improve the luminous efficiency or change the luminous wavelength.
The organic substance contained in the light-emitting layer may be a low-molecular-weight compound or a high-molecular-weight compound. Examples of the light-emitting material constituting the light-emitting layer include the following dye-based materials, metal complex-based materials, polymer-based materials, and dopant materials.

Examples of dye-based luminescent materials include cyclopentamine or its derivatives, tetraphenylbutadiene or its derivatives, triphenylamine or its derivatives, oxadiazole or its derivatives, pyrazoloquinoline or its derivatives, distyrylbenzene or its derivatives. derivatives, distyrylarylene or its derivatives, pyrrole or its derivatives, thiophene ring compounds, pyridine ring compounds, perinone or its derivatives, perylene or its derivatives, oligothiophene or its derivatives, oxadiazole dimer or its derivatives, pyrazoline dimer or derivatives thereof, quinacridone or derivatives thereof, coumarin or derivatives thereof, and the like;

Examples of metal complex-based light-emitting materials include rare earth metals such as Tb, Eu, and Dy, or Al, Zn, Be, Pt, and Ir. Examples thereof include metal complexes having imidazole, quinoline structures, etc. as ligands. Examples of metal complexes include metal complexes that emit light from a triplet excited state such as iridium complexes and platinum complexes, aluminum quinolinol complexes, benzoquinolinol beryllium complexes, benzoxazolylzinc complexes, benzothiazolezinc complexes, and azomethylzinc complexes. , porphyrin-zinc complex, phenanthroline-europium complex, and the like.

Polymer-based luminescent materials include, for example, polyparaphenylenevinylene or its derivatives, polythiophene or its derivatives, polyparaphenylene or its derivatives, polysilane or its derivatives, polyacetylene or its derivatives, polyfluorene or its derivatives, polyvinylcarbazole or In addition to derivatives thereof, materials obtained by polymerizing the dye materials and metal complex materials described above may be used.

Among the above light-emitting materials, materials that emit red light (hereinafter also referred to as "red light-emitting materials") include, for example, coumarin or derivatives thereof, thiophene ring compounds, polymers thereof, polyparaphenylene vinylene or derivatives thereof. , polythiophene or its derivatives, polyfluorene or its derivatives, and the like. Materials disclosed in Japanese Patent Application Laid-Open No. 2011-105701 can also be used as red light-emitting materials.

Materials that emit green light (hereinafter also referred to as "green light-emitting materials") include, for example, quinacridone or derivatives thereof, coumarin or derivatives thereof, polymers thereof, polyparaphenylene vinylene or derivatives thereof, polyfluorene or derivatives thereof, derivatives and the like. Materials disclosed in Japanese Patent Laid-Open No. 2012-036388 can also be used as green light-emitting materials.

Materials that emit blue light (hereinafter also referred to as “blue light emitting materials”) include, for example, distyrylarylene or derivatives thereof, oxadiazole or derivatives thereof, polymers thereof, polyvinylcarbazole or derivatives thereof, polyparallel Phenylene or derivatives thereof, polyfluorene or derivatives thereof, and the like are included. Materials disclosed in Japanese Unexamined Patent Application Publication No. 2012-144722 are also examples of blue light-emitting materials.

Dopant materials include, for example, perylene or its derivatives, coumarin or its derivatives, rubrene or its derivatives, quinacridone or its derivatives, squalium or its derivatives, porphyrin or its derivatives, styryl dyes, tetracene or its derivatives, pyrazolone or its derivatives, decacyclene or derivatives thereof, phenoxazone or derivatives thereof, and the like.

The optimum thickness of the light-emitting layer varies depending on the material used, and is appropriately determined in consideration of the required properties, ease of layer formation, and the like. The thickness of the light-emitting layer is, for example, 1 nm or more and 1 μm or less, preferably 2 nm or more and 500 nm or less, and more preferably 5 nm or more and 200 nm or less.

The electron injection layer is a layer having a function of improving electron injection efficiency from the cathode to the light emitting layer.
A known electron injection material can be used for the electron injection layer.
The thickness of the electron injection layer is, for example, 1 nm or more and 50 nm or less, although it varies depending on the material used.

(5) Arrangement Configuration and Film Thickness of Organic Layer Structure The organic layer structure is an element that forms the light emitting portion, and is basically within the light emitting region 14 defined by the bank 13 (the opening of the bank 13). The present invention is characterized in that the organic layer structure has a portion (A) arranged within the light emitting region 14 and a portion (B) arranged on the bank 13 . do.

FIG. 2 is a schematic cross-sectional view showing a partially enlarged bank periphery in an example of the organic EL device according to the present invention.
In the example shown in FIG. 2, the organic layer structure 1 has a portion (A) arranged within the light emitting region 14 and a portion (B) arranged above the bank 13 . The length of the portion where the organic layer structure portion 1 extends over the light emitting region 14 and onto the bank 13, that is, the length of the portion (B) is the length in the direction of the width W of the bank 13, which is the length _LB. Yes, and _LB is greater than zero and preferably less than the width W of bank 13 .

When the organic layer structure 1 is formed by a coating method or the like, the organic layer structure 1 has the thickest portion in the vicinity of the end portion of the bank 13 on the side of the light emitting region 14 .
In this specification, the maximum film thickness in the portion (A) of the organic layer structure portion 1 is referred to as " _TAS ". The position where the portion (A) has the maximum film thickness _TAS normally exists in a range from a position about 100 μm from the end of the bank 13 on the light emitting region 14 side to a position about 1000 μm from the end on the light emitting region 14 side. .
Further, in this specification, the central film thickness in the portion (A) of the organic layer structure portion 1 is referred to as "T _AC ". The center thickness _TAC refers to the thickness at the center point of the portion (A).
By forming the organic layer structure 1 to have the portion (B), that is, so that the end is located on the bank 13, the ratio T _AS /T _AC between T _AS and _TAC is brought close to 1. As a result, unevenness in light emission luminance within the light emitting region 14 can be reduced.
From the viewpoint of reducing unevenness in emission luminance, the ratio T _AS /T _AC is 1.0 or more and 1.1 or less, preferably 1.0 or more and 1.05 or less, and more preferably 1.0. .
As a method for forming the organic layer structure portion 1 having the portion (B), a coating method using a coating liquid for forming the organic layer constituting the organic layer structure portion 1 is preferable, and inkjet printing is more preferable. Law.

From the viewpoint of reducing unevenness in emission luminance, the length _LB is preferably 2.5 mm or more, more preferably 3 mm or more.
By setting the length _LB within the above range, it becomes easier to achieve T _AS /T _AC within the above numerical range.

From the viewpoint of reducing unevenness in light emission luminance over as wide a region as possible in the light emitting region 14, it is preferable that as many ends of the organic layer structure 1 as possible are located on the bank 13. More preferably, all the ends are located on bank 13 .

In this specification, the maximum film thickness in the portion (B) of the organic layer structure portion 1 is referred to as "T _BS ".
Referring to FIG. 2, the maximum film thickness _TBS in the portion (B) of the organic layer structure 1 is preferably larger than the central film thickness _TAC in the portion (A). Such a thickness relationship can be realized by adopting a coating method for forming the organic layer structure portion 1 and then adjusting the concentration and viscosity of the coating liquid, the coating film drying method, and the like.
Satisfying the thickness relationship described above is advantageous in providing an organic EL device having a light emitting region with reduced unevenness in light emission luminance.

The central thickness T _AC in the portion (A) of the organic layer structure 1, the maximum thickness T _AS in the portion (A), and the maximum thickness T _BS in the portion (B) were determined by carefully cutting the fabricated organic EL device. A scanning transmission electron microscope is used to acquire an image of the cross section exposed by the exposure, and one point arbitrarily selected from this image is actually measured according to the above definition.
The length L _B of the portion (B) (the same applies to L _B1 , L _B2 and L _B3 described later) is measured for the formed organic layer structure portion 1 (or organic layer) using a precision length measuring machine. .

The value of the central thickness _TAC in the portion (A) of the organic layer structure portion 1 is, for example, 10 nm or more and 10 μm or less, preferably 50 nm or more and 5 μm or less.

(6) First organic layer The first organic layer is an organic layer that constitutes the organic layer structure portion, and when the organic layer structure portion is composed of two or more organic layers, the first organic layer among these organic layers It is an organic layer arranged near the electrode 12 .
The first organic layer has a portion (A1) disposed within the light emitting region 14 and a portion (B1) disposed on the bank 13 from the viewpoint of reducing unevenness in light emission luminance within the light emitting region 14. is preferred. The length of the portion where the first organic layer extends over the light emitting region 14 and onto the bank 13, that is, the portion (B1) is the length in the width W direction of the bank 13, and is the length L _B1 . , L _B1 are greater than zero and preferably less than the width W of the bank 13 .
From the viewpoint of reducing unevenness in light emission luminance over as wide a region as possible in the light emitting region 14, it is preferable that as many ends of the first organic layer as possible are located on the bank 13. More preferably, the ends are located on the bank 13 .
As a method for forming the first organic layer having the portion (B1), a coating method using a coating liquid for forming the first organic layer is preferable, and an inkjet printing method is more preferable.

The value of the center thickness of the portion (A1) of the first organic layer is not particularly limited as long as the function of the first organic layer is exhibited, and may be a thickness according to the function. Also, the optimum value of the central film thickness may vary depending on the material of the first organic layer.
For example, when the first organic layer is a hole injection layer, its center thickness is, for example, 1 nm or more and 1 μm or less, preferably 2 nm or more and 500 nm or less, more preferably 5 nm or more and 200 nm or less.
For example, when the first organic layer is a light-emitting layer, its center thickness is, for example, 1 nm or more and 2 μm or less, preferably 5 nm or more and 500 nm or less, more preferably 10 nm or more and 200 nm or less.
For example, when the first organic layer is an electron injection layer, its center thickness is, for example, 1 nm or more and 50 nm or less.

(7) Organic Layers Other than the First Organic Layer The organic layer structure 1 formed in the light emitting region 14 can include organic layers other than the first organic layer. Other organic layers other than the first organic layer include a second organic layer provided adjacent to the first organic layer (the side opposite to the first electrode 12 side of the first organic layer), and the second organic layer. A third organic layer provided adjacent to (the side opposite to the first electrode 12 side in the second organic layer) and the like can be mentioned. Of course, the organic layer structure 1 may contain four or more organic layers.

The layer structure of the organic layer structure portion having only the first organic layer as the organic layer, and the layer structure of the organic layer structure portion including the first organic layer and other organic layers other than the first organic layer include, for example, Examples of the layer structure are as follows.
(a) first electrode/light emitting layer/second electrode (b) first electrode/hole injection layer/light emitting layer/second electrode (c) first electrode/hole injection layer/light emitting layer/electron injection layer/ Second electrode (d) first electrode/hole injection layer/light emitting layer/electron transport layer/electron injection layer/second electrode (e) first electrode/hole injection layer/hole transport layer/light emitting layer/second electrode 2 electrodes (f) first electrode/hole injection layer/hole transport layer/light emitting layer/electron injection layer/second electrode (g) first electrode/hole injection layer/hole transport layer/light emitting layer/electrons transport layer/electron injection layer/second electrode (h) first electrode/light emitting layer/electron injection layer/second electrode (i) first electrode/light emitting layer/electron transport layer/electron injection layer/second electrode where , the symbol "/" indicates that each layer sandwiching the symbol "/" is laminated adjacently.
The first electrode is for example an anode and the second electrode is for example a cathode.

A hole-transporting layer is a layer having a function of improving hole injection from an anode, a hole-injecting layer, or the like to a light-emitting layer.
A known hole-transporting material can be used as the material for the hole-transporting layer. Materials for the hole transport layer include, for example, polyvinylcarbazole or derivatives thereof, polysilane or derivatives thereof, polysiloxane having an aromatic amine in the side chain or main chain or derivatives thereof, pyrazoline or derivatives thereof, arylamines or derivatives thereof, stilbene or derivatives thereof, triphenyldiamine or derivatives thereof, polyaniline or derivatives thereof, polythiophene or derivatives thereof, polyarylamines or derivatives thereof, polypyrrole or derivatives thereof, poly(p-phenylene vinylene) or derivatives thereof, and poly(2, 5-thienylene vinylene) or derivatives thereof. Further, a hole transport material disclosed in JP-A-2012-144722 can also be mentioned.

When the second organic layer is a hole transport layer, the central film thickness of the second organic layer (the film thickness at the center of the second organic layer) varies depending on the material used, but is, for example, 1 nm or more and 1 μm or less. , preferably 2 nm or more and 500 nm or less, more preferably 5 nm or more and 200 nm or less. The same applies when the third organic layer is a hole transport layer.

The electron transport layer is a layer having a function of improving electron injection from the cathode, electron injection layer, or the like. A known electron transport material can be used for the electron transport layer.
When the second organic layer is an electron transport layer, the central film thickness of the second organic layer (film thickness at the center of the second organic layer) varies depending on the material used, but is, for example, 1 nm or more and 1 μm or less, It is preferably 2 nm or more and 500 nm or less, more preferably 5 nm or more and 200 nm or less. The same applies when the third organic layer is an electron transport layer.

FIG. 3 is a schematic cross-sectional view showing a partially enlarged bank periphery in another example of the organic EL device according to the present invention. The organic EL device shown in FIG. 3 includes an organic layer structure 1 having a two-layer structure of a first organic layer 1a and a second organic layer 1b.
As shown in FIG. 3, when the organic layer structure 1 includes the first organic layer 1a and the second organic layer 1b disposed on the first organic layer 1a, the unevenness of the light emission luminance within the light emitting region 14 is caused. from the viewpoint of reducing the second organic layer 1b preferably has a portion (A2) arranged in the light-emitting region 14 and a portion (B2) arranged on the bank 13 . The length of the portion where the second organic layer 1b extends over the light emitting region 14 and onto the bank 13, that is, the portion (B2) is the length in the direction of the width W of the bank 13, which is the length _LB2 . Yes, and _LB2 is greater than zero and preferably less than the width W of bank 13 .

From the viewpoint of reducing unevenness in light emission luminance within the light emitting region 14, the length L _B2 of the portion (B2) of the second organic layer 1b is the same as the length L _B1 of the portion (B1) of the first organic layer 1a. or greater.
The difference between the length L _B2 and the length L _B1 is preferably 0 mm or more and 1 mm or less from the viewpoint of reducing unevenness in light emission luminance within the light emission region 14 .
In the organic EL device shown in FIG. 3, the length _LB2 of the portion (B2) of the second organic layer 1b is the same as the length _LB of the portion (B) of the organic layer structure portion 1 shown in FIG. be.

From the viewpoint of reducing unevenness in light emission luminance over as wide a region as possible in the light emitting region 14, it is preferable that as many ends of the second organic layer 1b as possible are located on the bank 13. More preferably, all the ends are located on bank 13 .

Although not shown, the same applies to the case where the organic layer structure 1 further includes a third organic layer disposed on the second organic layer 1b. From the point of view, the third organic layer preferably has a portion (A3) arranged within the light emitting region 14 and a portion (B3) arranged on the bank 13 . The length of the portion where the third organic layer extends over the light emitting region 14 and onto the bank 13, that is, the portion (B3) is the length in the width W direction of the bank 13, and is the length _LB3 . , _LB3 are greater than zero and preferably less than the width W of the bank 13 .

From the viewpoint of reducing unevenness in light emission luminance within the light emitting region 14, the length L _B3 of the portion (B3) of the third organic layer is the same as the length L _B2 of the portion (B2) of the second organic layer 1b. or preferably larger.
The difference between the length L _B3 and the length L _B2 is preferably 0 mm or more and 1 mm or less from the viewpoint of reducing unevenness in light emission luminance within the light emission region 14 .

From the viewpoint of reducing unevenness in light emission luminance over as wide a region as possible in the light emitting region 14, it is preferable that as many ends of the third organic layer as possible are located on the bank 13. More preferably, the ends are located on the bank 13 .

The film thickness and length of each organic layer constituting the organic layer structure portion 1 can be measured in the same manner as the various film thicknesses and lengths of the organic layer structure portion 1 .

(8) Second electrode The second electrode is, for example, a cathode.
A cathode is provided on one or more organic layers included in the light-emitting portion.
As a material for the cathode, a material having a small work function, easy injection of electrons into the light-emitting layer, and high electrical conductivity is preferable. When the organic EL device emits light from the anode side, a material having a high visible light reflectance is preferable as the cathode material so that the cathode reflects the light emitted from the light-emitting layer toward the anode side.
Specifically, alkali metals, alkaline earth metals, transition metals, group 13 metals of the periodic table, or the like can be used for the cathode, for example. A transparent conductive cathode made of a conductive metal oxide, a conductive organic substance, or the like can also be used as the cathode.

The thickness of the cathode is appropriately set in consideration of electrical conductivity and durability. The thickness of the cathode is, for example, 10 nm or more and 10 μm or less, preferably 20 nm or more and 1 μm or less, and more preferably 50 nm or more and 500 nm or less.

When the organic EL device has two or more light-emitting regions 14 (thus, two or more light-emitting portions), a cathode may be provided for each light-emitting region, or a common cathode for all light-emitting regions 14 across the bank 13 may be provided. may be provided.

A sealing substrate is usually provided on the second electrode of the organic EL device. In addition, the organic EL device may include other known elements included in, for example, an organic EL lighting device or an organic EL display.

<Method for manufacturing organic EL device>
A method for manufacturing an organic EL device according to one embodiment of the present invention includes the following steps.
a step of forming a bank 13 having a thickness and a width on the substrate 11 for defining the light emitting region 14 (bank forming step);
a step of controlling the liquid repellency of the upper surface of the bank 13 (liquid repellency control step);
A step of forming an organic layer structure by a coating method on the substrate 11 on which the bank 13 is formed (organic layer structure forming step).
The manufacturing method according to the present invention is suitable as a method for manufacturing the organic EL device according to the present invention.

The organic layer structure forming step usually includes the step of forming the first organic layer 1a described above. The first organic layer 1a can be formed by the following steps.
A step of applying a coating liquid for forming the first organic layer to form a first coating film (first coating step), and a step of drying the first coating film to form the first organic layer 1a (first drying process).

When the organic layer structure 1 includes the second organic layer 1b arranged on the first organic layer 1a, the manufacturing method further includes the following steps after the first drying step.
A step of applying a coating liquid for forming a second organic layer on the first organic layer 1a to form a second coating film (second coating step), and drying the second coating film to form a second organic layer 1b (second drying step).

When the organic layer structure 1 includes a third organic layer disposed on the second organic layer 1b, the manufacturing method further includes the following steps after the second drying step.
a step of applying a coating liquid for forming a third organic layer on the second organic layer 1b to form a third coating film (third coating step); and drying the third coating film to form a third organic layer. Forming step (third drying step).

(1) Bank Forming Process The bank forming process is usually a process of manufacturing a banked substrate 10 as shown in FIG. 1, for example. The substrate 11, the first electrodes 12 and the banks 13 that constitute the substrate 10 with banks, and the method of manufacturing the substrate 10 with banks are described above.

(2) Liquid Repellency Control Process As described above, from the viewpoint of suitably defining (dividing) the light emitting region 14 by the bank 13 and from the viewpoint of preventing the organic layer from spreading outside the bank 13 by wetting. At least the upper surface of the bank 13 (the surface opposite to the substrate 11) preferably has liquid repellency, and it is more preferred that the upper surface and side surfaces have liquid repellency. The liquid repellency control process is a process for adjusting the liquid repellency of at least the upper surface of the bank 13 .
The fact that at least the top surface of the bank 13 has liquid repellency suppresses uneven contraction of the coating film in the drying process of heating the coating film formed in contact with at least the top surface of the bank 13 to form an organic layer. It is also advantageous for

Methods for adjusting (controlling) the liquid repellency of at least the upper surface of the bank 13 include a layer made of a thermoplastic resin composition containing a liquid repellent agent, a layer made of a cured photosensitive resin composition containing a liquid repellent agent, or a layer made of a cured photosensitive resin composition containing a liquid repellent agent. A method of forming the bank 13 as a layer made of a cured product of a thermosetting resin composition containing a liquid agent, a layer made of a thermoplastic resin, a layer made of a cured product of a photosensitive resin composition, or a layer made of a cured product of a thermosetting resin composition. For example, after forming the bank 13 as a layer made of a cured product, at least the upper surface of the bank 13 is subjected to a liquid-repellent treatment.
In the former case, the liquid repellency control process is part of the bank formation process.
Examples of the liquid-repellent treatment in the latter case include a treatment of applying a liquid-repellent agent containing a fluorine resin or the like, and a treatment of irradiating the coated surface with an active energy ray such as ultraviolet rays after applying the liquid-repellent agent.
The liquid repellency of at least the upper surface of the bank 13 may be controlled by UV ozone treatment.
On at least the upper surface of a layer made of a thermoplastic resin composition containing a liquid repellent agent, a layer made of a cured photosensitive resin composition containing a liquid repellent agent, or a layer made of a cured thermosetting resin composition containing a liquid repellent agent The liquid-repellent treatment may be further applied.

Since it is more advantageous in providing an organic EL device having a light emitting region with reduced unevenness in light emission luminance, the liquid repellency control step is performed so that the contact angle of the upper surface of the bank 13 with respect to the coating liquid (< organic EL device > section) is preferably less than 10 degrees, more preferably less than 9 degrees, and even more preferably less than 8 degrees. include. Preferably, the contact angle of the side surface of the bank 13 with respect to the coating liquid is preferably less than 10 degrees, more preferably 9 degrees or less, further preferably less than 8 degrees, by this liquid repellency control step. The liquid repellency of the side surface of the bank 13 is adjusted so that
The contact angle is usually the contact angle with respect to the coating liquid for forming the first organic layer.

(3) Organic layer structure forming step The organic layer structure 1 can be formed by a coating method of applying a coating liquid and then drying the coating film.
Examples of the method of applying the coating liquid include an inkjet printing method. However, other known coating methods such as micro gravure coating, gravure coating, bar coating, roll coating, wire bar coating, and spraying can be used as long as the coating method can form a layer in the openings of the banks 13. A coating method, screen printing method, flexographic printing method, offset printing method, or nozzle printing method may be used.

The solvent contained in the coating liquid is not particularly limited as long as it can dissolve the functional material contained in the coating liquid. Examples include chloride solvents such as chloroform, methylene chloride and dichloroethane; ether solvents such as tetrahydrofuran and butyl cellosolve; and toluene. , xylene, cyclohexylbenzene and other aromatic hydrocarbon solvents; acetone, methyl ethyl ketone, cyclohexanone and other ketone solvents; ethyl acetate, butyl acetate, ethyl cellosolve acetate, butyl lactate and other ester solvents; methanol, ethanol, propanol, 2-ethyl Alcohol solvents such as hexanol and the like are included.
Only one solvent may be used, or two or more solvents may be used in combination.

A method for drying the coating film is not particularly limited as long as the first coating film can be dried, and examples thereof include vacuum drying and heat drying.

The organic layer structure 1 may be composed of two or more organic layers. In this case, two or more organic layers are formed by repeating the coating and drying described above.

The organic layer structure portion 1 has a portion (A) disposed within the light emitting region 14 and a portion (B) having a length _LB in the width W direction of the bank 13 and disposed above the bank 13 . implemented as follows. Length _LB is greater than zero and preferably less than width W of bank 13 .

By forming the organic layer structure 1 to have the portion (B), that is, so that the end is located on the bank 13, the ratio T _AS /T _AC between T _AS and _TAC is brought close to 1. As a result, unevenness in light emission luminance within the light emitting region 14 can be reduced.
From the viewpoint of reducing unevenness in emission luminance, the ratio T _AS /T _AC is 1.0 or more and 1.1 or less, preferably 1.0 or more and 1.05 or less, and more preferably 1.0. .

From the viewpoint of reducing unevenness in emission luminance, the length _LB is preferably 2.5 mm or more, more preferably 3 mm or more.
By setting the length _LB within the above range, it becomes easier to achieve T _AS /T _AC within the above numerical range.

From the viewpoint of reducing unevenness in light emission luminance over as wide a region as possible in the light emitting region 14, the organic layer structure 1 is preferably formed so that as many ends as possible are located on the bank 13, and all the ends are located on the bank 13. It is more preferable that the portion is formed so as to be positioned on bank 13 .

The organic layer structure 1 is preferably formed such that the maximum thickness _TBS in the portion (B) is larger than the central thickness _TAC in the portion (A). Such a thickness relationship can be realized by adjusting the concentration and viscosity of the coating liquid, the coating film drying method, and the like in the coating method using the coating liquid.
Satisfying the thickness relationship described above is advantageous in providing an organic EL device having a light emitting region with reduced unevenness in light emission luminance.

(4) Formation of First Organic Layer On the substrate 11 on which the banks 13 are formed, more specifically, the openings (light-emitting regions 14) of the banks 13 are coated with a coating solution for forming the first organic layer to form a first organic layer. By forming one coating film (first coating step) and then drying the first coating film (first drying step), the first organic layer 1a can be formed.
The coating liquid for forming the first organic layer may be a coating liquid containing a hole injection material, a coating liquid containing a light emitting material, a coating liquid containing an electron injection material, or the like. Examples of the method of applying the coating liquid and the method of drying the coating film are as described above.

From the viewpoint of reducing unevenness in light emission luminance within the light emitting region 14, the first coating step is performed so that the first organic layer 1a obtained through the first drying step is disposed within the light emitting region 14 (A1). , and a portion (B1) arranged on the bank 13 with a length L _B1 in the width W direction of the bank 13 . Length L _B1 is greater than zero and preferably less than width W of bank 13 .

(5) Formation of organic layers other than the first organic layer A coating solution for forming a second organic layer is applied onto the first organic layer 1a to form a second coating film (second coating step), Then, by drying the second coating film (second drying step), the second organic layer 1b can be formed.
The coating liquid for forming the second organic layer may be a coating liquid containing a hole-transporting material, a coating liquid containing a light-emitting material, a coating liquid containing an electron-transporting material, a coating liquid containing an electron-injecting material, or the like.
Examples of the solvent contained in the coating liquid for forming the second organic layer, the coating method of the coating liquid, and the drying method of the coating film are as described above.

From the viewpoint of reducing unevenness in light emission luminance within the light emitting region 14, the second coating step is performed so that the second organic layer 1b obtained through the second drying step is disposed within the light emitting region 14 (A2). , and a portion (B2) arranged on the bank 13 with a length _LB2 in the width W direction of the bank 13 . Length _LB2 is greater than zero and preferably less than width W of bank 13 .

From the viewpoint of reducing unevenness in light emission luminance within the light emitting region 14, the length L _B2 of the portion (B2) of the second organic layer 1b is the same as the length L _B1 of the portion (B) of the first organic layer 1a. or greater.
The difference between the length L _B2 and the length L _B1 is preferably 0 mm or more and 1 mm or less from the viewpoint of reducing unevenness in light emission luminance within the light emission region 14 .

From the viewpoint of reducing unevenness in light emission luminance over as wide a region as possible in the light emitting region 14, the second coating step is performed so that as many ends as possible of the second organic layer 1b obtained through the second drying step are located on the banks 13. More preferably, all the ends of the second organic layer 1 b are located on the bank 13 .

On the second organic layer 1b, a coating liquid for forming a third organic layer is applied to form a third coating film (third coating step), and then the third coating film is dried (third drying step ) to form a third organic layer.
The coating liquid for forming the third organic layer includes a coating liquid containing a light-emitting material, a coating liquid containing an electron-transporting material, a coating liquid containing an electron-injecting material, a coating liquid containing a hole-transporting material, and a coating liquid containing a hole-injecting material. It can be a liquid or the like.
Examples of the solvent contained in the coating liquid for forming the third organic layer, the coating method of the coating liquid, and the drying method of the coating film are as described above.

From the viewpoint of reducing unevenness in light emission luminance within the light emitting region 14, the third coating step includes a portion (A3) where the third organic layer obtained through the third drying step is disposed within the light emitting region 14, and a portion (B3) arranged on the bank 13 with a length _LB3 in the width W direction of the bank 13 . Length _LB3 is greater than zero and preferably less than width W of bank 13 .

From the viewpoint of reducing unevenness in light emission luminance within the light emitting region 14, the length L _B3 of the portion (B3) of the third organic layer is the same as the length L _B2 of the portion (B2) of the second organic layer 1b. or preferably larger.
The difference between the length L _B3 and the length L _B2 is preferably 0 mm or more and 1 mm or less from the viewpoint of reducing unevenness in light emission luminance within the light emission region 14 .

From the viewpoint of reducing unevenness in light emission luminance over as wide a region as possible in the light emitting region 14, the third coating step is performed so that as many ends as possible of the third organic layer obtained through the third drying step are located on the bank 13. and more preferably so that all the ends of the third organic layer are located on the bank 13 .

In the case where the organic layer structure portion 1 has four or more organic layers, the fourth and subsequent organic layers can be formed in the same manner as the first to third organic layers.

An organic EL device can be obtained by performing a step of forming a second electrode (for example, a cathode) after forming a desired one or more organic layers. As a method of forming the second electrode, for example, the same vapor deposition method and coating method as in the case of the first electrode 12 can be used.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

The measurement methods for the following items are as follows.
[a] Contact angle of bank top surface and side surface The contact angle of the top surface and side surface of the bank 13 with respect to the coating liquid for forming the first organic layer was measured using "Auto Dispenser System AD-31S" (manufactured by Kyowa Interface Science Co., Ltd.). , and the temperature was 23°C.

[b] Film thickness and length of layer portion The central film thickness and the maximum film thickness of the organic layer structure portion were measured according to the above definitions. Specifically, a cross section exposed by carefully cutting the fabricated organic EL device is imaged using a scanning transmission electron microscope, and one point arbitrarily selected from this image is centered according to the definition above. The film thickness and maximum film thickness were measured.
The length of the layer portion such as _LB was measured using a precision length measuring machine. The values of L _B , L _B1 , L _B2 , L _B3 and L _B4 shown in Table 1 below are averages of measured values at the center position of each side of the organic layer structure or the organic layer formed in a square shape. (average of 4 points).

<Experimental example 1>
A substrate 10 with banks having the configuration shown in FIG. 1 was prepared.
The outer shape of the substrate 11 was a square with a side length of about 50 mm. The material of the substrate 11 is glass.
The external shape of the bank 13 was a square with a side length of about 34 mm, the opening shape of the bank 13 was a square with a side length of about 22 mm, and the width W of the bank 13 was about 6 mm. The bank 13 is a layer (single-layer structure) formed by curing a photosensitive resin composition containing a liquid-repellent agent. The contact angle of the upper surface and side surface of the bank 13 with respect to the coating liquid for forming the organic layer was reduced to about 8 degrees.
The bank 13 is aligned to be located directly over a portion of the periphery of the first electrode 12 (anode).

A first organic layer 1a (hole injection layer) was formed in the light emitting region 14 (opening of the bank 13) of the banked substrate 10 by the following procedure.
A coating liquid for forming a first organic layer containing a hole injection material was prepared.
Using this coating liquid, a first coating film was formed on the light emitting region 14 by an inkjet printing method, and then the first coating film was dried with a hot plate to form the first organic layer 1a.
Table 1 shows the length L _B1 of the portion (B1) of the first organic layer 1a.
All the ends of the first organic layer 1 a in this experimental example were located on the bank 13 .

Next, a second organic layer 1b (hole transport layer) was formed on the first organic layer 1a by the following procedure.
A coating liquid for forming a second organic layer containing a hole transport material was prepared.
This coating liquid was used to form a second coating film on the first organic layer 1a by an inkjet printing method, and then the second coating film was dried with a hot plate to form a second organic layer 1b.
Table 1 shows the length L _B2 of the portion (B2) of the second organic layer 1b.
All the ends of the second organic layer 1b in this experimental example were located on the bank 13 .

Next, a third organic layer (light-emitting layer) was formed on the second organic layer 1b by the following procedure.
A coating liquid for forming a third organic layer containing a light-emitting material was prepared.
This coating liquid was used to form a third coating film on the second organic layer 1b by an inkjet printing method, and then the third coating film was dried with a hot plate to form a third organic layer.
Table 1 shows the length L _B3 of the portion (B3) of the third organic layer.
All edges of the third organic layer in this experimental example were located on the bank 13 .

Next, a fourth organic layer (electron transport layer) was formed on the third organic layer. A coating liquid for forming a fourth organic layer containing an electron transporting material was prepared. Using this coating liquid, a fourth coating film was formed on the third organic layer by an inkjet printing method, and then the fourth coating film was dried with a hot plate to form a fourth organic layer.
Next, an electron injection layer (inorganic layer) and a cathode were formed on the fourth organic layer by a vapor deposition method and sealed in a nitrogen atmosphere to obtain an organic EL device.
Table 1 shows the length L _B4 of the portion (B4) of the fourth organic layer.

<Experimental Examples 2 and 3>
By adjusting the forming conditions of the first to fourth organic layers, the central film thickness T _AC and the maximum film thickness T _AS of the portion (A) of the organic layer structure portion and the maximum film thickness T _BS of the portion (B) An organic EL device was fabricated in the same manner as in Experimental Example 1 except that the length _LB was set as shown in Table 1.

(Evaluation of luminance unevenness)
For the obtained organic EL device, the same voltage was applied to cause the light emitting region to emit light, and an image of the light emitting region was obtained. In the obtained image, the color tone between the central portion and the peripheral portion (near the bank) of the light emitting region was observed, and unevenness in light emission luminance was evaluated according to the following evaluation criteria.
A: There is no difference in color, or almost no difference.
B: There is a clear difference in color.

As described above, the values of L _B , L _B1 , L _B2 , L _B3 and L _B4 shown in Table 1 are measured at the center position of each side of the organic layer structure or organic layer formed in a square shape. (average of 4 points). The organic EL devices of Experimental Examples 1 to 3 had _LB values substantially equal to the average values shown in Table 1 at any position of the portion (B) formed over the entire circumference of the bank 13. Ta. The same was true for L _B1 , L _B2 , L _B3 and L _B4 .

1 organic layer structure, 1a first organic layer, 1b second organic layer, 10 substrate with bank, 11 substrate, 12 first electrode, 13 bank, 14 light emitting region.

Claims (11)

An organic EL device having a light emitting region,
a substrate;
a bank having a thickness and a width disposed on the substrate so as to surround the light emitting region;
an organic layer structure;
including
The organic layer structure portion has a portion (A) disposed within the light emitting region and a portion (B) disposed above the bank and having a length _LB in the width direction of the bank. death,
The organic layer structure portion has the following formula, where _TAS is the maximum thickness in the portion (A) and _TAC is the central thickness in the portion (A):
T _AS /T _AC ≤1.1
contains a portion that satisfies
An organic EL device, wherein the maximum thickness _TBS in said portion (B) is greater than the central thickness _TAC in said portion (A). An organic EL device having a light emitting region,
a substrate;
a bank having a thickness and a width disposed on the substrate so as to surround the light emitting region;
an organic layer structure;
including
The organic layer structure portion has a portion (A) disposed within the light emitting region and a portion (B) disposed above the bank and having a length _LB in the width direction of the bank. death,
The organic layer structure portion has the following formula, where _TAS is the maximum thickness in the portion (A) and _TAC is the central thickness in the portion (A):
T _AS /T _AC ≤1.1
contains a portion that satisfies
The organic EL device, wherein the _LB is 2.5 mm or more. An organic EL device having a light emitting region,
a substrate;
a bank having a thickness and a width disposed on the substrate so as to surround the light emitting region;
an organic layer structure;
including
The organic layer structure portion has a portion (A) disposed within the light emitting region and a portion (B) disposed above the bank and having a length _LB in the width direction of the bank. death,
The organic layer structure portion has the following formula, where _TAS is the maximum thickness in the portion (A) and _TAC is the central thickness in the portion (A):
T _AS /T _AC ≤1.1
contains a portion that satisfies
The organic layer structure part is composed of two or more organic layers,
the organic layer structure includes a first organic layer and a second organic layer disposed on the first organic layer;
The first organic layer has a portion (A1) arranged within the light emitting region and a portion (B1) arranged above the bank and having a length L _B1 in the width direction of the bank. death,
The second organic layer has a portion (A2) arranged within the light emitting region and a portion (B2) arranged above the bank and having a length _LB2 in the width direction of the bank. death,
An organic EL device, wherein said _LB2 is the same as or greater than said _LB1 . An organic EL device having a light emitting region,
a substrate;
a bank having a thickness and a width disposed on the substrate so as to surround the light emitting region;
an organic layer structure;
including
The organic layer structure portion has a portion (A) disposed within the light emitting region and a portion (B) disposed above the bank and having a length _LB in the width direction of the bank. death,
The organic layer structure portion has the following formula, where _TAS is the maximum thickness in the portion (A) and _TAC is the central thickness in the portion (A):
T _AS /T _AC ≤1.1
contains a portion that satisfies
The organic EL device, wherein the light emitting region has a rectangular shape with at least one side having a length of 1 mm or more. The organic EL device according to any one of claims 1 to 4, wherein all edges of said organic layer structure are located on said bank. 6. The organic EL device according to claim 1, wherein at least the upper surface of said bank has liquid repellency. The organic EL device according to any one of claims 1 to 6, wherein said bank has a single layer structure. A method for manufacturing an organic EL device having a light-emitting region, comprising:
forming on a substrate a bank having a thickness and a width for defining the light emitting region;
controlling the liquid repellency of at least the upper surface of the bank;
a step of forming an organic layer structure by a coating method on the substrate on which the bank is formed;
including
The organic layer structure has a portion (A) arranged within the light emitting region and a portion (B) having a length _LB in the width direction of the bank and arranged above the bank. In addition, when the maximum film thickness at the portion (A) is T _AS and the central film thickness at the portion (A) is _TAC , the following formula:
T _AS /T _AC ≤1.1
is formed to include a portion that satisfies
A method of manufacturing an organic EL device, wherein the organic layer structure portion is formed such that the maximum thickness _TBS in the portion (B) is larger than the central thickness _TAC in the portion (A). A method for manufacturing an organic EL device having a light-emitting region, comprising:
forming on a substrate a bank having a thickness and a width for defining the light emitting region;
controlling the liquid repellency of at least the upper surface of the bank;
a step of forming an organic layer structure by a coating method on the substrate on which the bank is formed;
including
The organic layer structure has a portion (A) arranged within the light emitting region and a portion (B) having a length _LB in the width direction of the bank and arranged above the bank. In addition, when the maximum film thickness at the portion (A) is T _AS and the central film thickness at the portion (A) is _TAC , the following formula:
T _AS /T _AC ≤1.1
is formed to include a portion that satisfies
The method for manufacturing an organic EL device, wherein the organic layer structure portion is formed such that the _LB is 2.5 mm or more. A method for manufacturing an organic EL device having a light-emitting region, comprising:
forming on a substrate a bank having a thickness and a width for defining the light emitting region;
controlling the liquid repellency of at least the upper surface of the bank;
a step of forming an organic layer structure by a coating method on the substrate on which the bank is formed;
including
The organic layer structure has a portion (A) arranged within the light emitting region and a portion (B) having a length _LB in the width direction of the bank and arranged above the bank. In addition, when the maximum film thickness at the portion (A) is T _AS and the central film thickness at the portion (A) is _TAC , the following formula:
T _AS /T _AC ≤1.1
is formed to include a portion that satisfies
The organic layer structure part is composed of two or more organic layers,
The step of forming the organic layer structure includes
a step of applying a coating liquid for forming a first organic layer on the substrate on which the banks are formed to form a first coating film;
drying the first coating film to form a first organic layer;
a step of applying a coating liquid for forming a second organic layer on the first organic layer to form a second coating film;
drying the second coating film to form a second organic layer;
including
The first organic layer has a portion (A1) arranged within the light emitting region and a portion (B1) arranged above the bank and having a length L _B1 in the width direction of the bank. is formed as
The second organic layer has a portion (A2) arranged within the light emitting region and a portion (B2) arranged above the bank and having a length _LB2 in the width direction of the bank. and the L _B2 is formed to be the same as or larger than the L _B1 . A method for manufacturing an organic EL device having a light-emitting region, comprising:
forming on a substrate a bank having a thickness and a width for defining the light emitting region;
controlling the liquid repellency of at least the upper surface of the bank;
a step of forming an organic layer structure by a coating method on the substrate on which the bank is formed;
including
The organic layer structure has a portion (A) arranged within the light emitting region and a portion (B) having a length _LB in the width direction of the bank and arranged above the bank. In addition, when the maximum film thickness at the portion (A) is T _AS and the central film thickness at the portion (A) is _TAC , the following formula:
T _AS /T _AC ≤1.1
is formed to include a portion that satisfies
The step of forming the organic layer structure includes
a step of applying a coating liquid for forming a first organic layer on the substrate on which the banks are formed to form a first coating film;
drying the first coating film to form a first organic layer;
including
The method of manufacturing an organic EL device, wherein the step of controlling the liquid repellency includes the step of setting the contact angle of at least the upper surface of the bank to the coating liquid for forming the first organic layer to less than 10 degrees.

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