TW201724613A - Method for manufacturing organic EL device and organic EL device - Google Patents

Abstract

One embodiment relating to a method for manufacturing organic EL device 1 containing a step of forming an organic light-emitting layer 23 by coating on a first electrode 12 concained in bank-containing substrate 10 and provided on a pixel area 2a defined by a bank 13, a step of calculating the flatness of the organic light-emitting layer, a step of determining whether the flatness reaches the desired flatness, and a step of forming a second electrode 30. While the smallest thickness of the organic light-emitting layer being taken as d (nm), an area of the organic light-emitting layer at (d+ predetermined value) nm or less being taken as A1, an area of the pixel area being as taken as A2, the flatness is presented by (A1/A2)*100, If the flatness reaches the desived valve in the determining step, the step of forming the second electrod is performed. If the flatness is less than the desired value in the determining step, the forming conditions for organic light-emitting layer are changed to for the organic light-emitting layer.

Description

Method for manufacturing organic EL device and organic EL device

The present invention relates to a method of producing an organic EL device and an organic EL device.

In the organic EL device, as in Patent Document 1, it is known that a plurality of pixels are defined by a bank (bank). In this organic EL device, an organic light-emitting layer is provided in each pixel, and each pixel emits light.

[Previous Technical Literature] [Patent Literature]

Patent Document 1: Japanese International Publication No. 2008/149499

When the thickness of the organic light-emitting layer in the pixel of the organic EL device is not uniform, the luminance characteristics (for example, uniformity of luminance, etc.) in the pixel are deteriorated. In order to make the thickness of the organic light-emitting layer uniform, that is, to form a flat layer of the organic light-emitting layer, it is required to be the bottom layer of the organic light-emitting layer. The layer is first formed flat. However, at this time, the flatness of the layers must be evaluated for each layer, making the manufacturing steps cumbersome. In addition, since the relationship between the flatness of the organic light-emitting layer and the brightness is unknown, it is not possible to determine whether or not a desired luminance characteristic is obtained until an organic EL device is fabricated and an organic electrode is formed on the organic light-emitting layer. Therefore, in the case where the desired luminance characteristics are not obtained, it is necessary to form not only the organic light-emitting layer but also the electrode to be provided in the organic light-emitting layer, and the productivity of the organic EL device is lowered.

Therefore, an object of the present invention is to provide a method for producing an organic EL device and an organic EL device which can improve productivity.

In other words, the method of manufacturing an organic EL device according to the present invention includes: providing a substrate, a bank for providing a predetermined pixel on the substrate, and a pixel region corresponding to the pixel in the substrate; a step of forming an organic light-emitting layer by a coating method on the first electrode of the substrate on which the first electrode is attached, and calculating a flatness of the organic light-emitting layer, and determining whether the flatness of the organic light-emitting layer is desired And a step of forming a second electrode on the organic light-emitting layer; and in the step of calculating the flatness, setting a minimum thickness of the organic light-emitting layer to d (nm), from a thickness of the substrate The area of the organic light-emitting layer having a (d+established value) nm or less in the direction of viewing is A1, the area of the pixel region is A2, and when the flatness is α, the flatness is calculated by the following formula (1). And in the determining step, when the flatness is equal to or greater than a desired value, performing the forming of the second electric In the step of determining, when the flatness does not reach a desired value, the organic light-emitting layer is formed by changing the formation conditions of the organic light-emitting layer in the step of forming the organic light-emitting layer.

α=(A1/A2)×100‧‧‧(1)

In the inventors of the present application, when the flatness of the organic light-emitting layer formed in the pixel defined by the bank is defined as described above, it is found that there is a certain degree between the flatness and the brightness state from the organic light-emitting layer. Relationship.

In the above manufacturing method, an organic EL device having an organic light-emitting layer having a flatness of a desired value or more in a pixel can be manufactured. In the organic EL device, according to what has been found by the inventors of the present application, light can be emitted from a pixel substantially in a luminance state corresponding to the above-described desired value. At this time, in the production of the organic EL device, by adjusting the flatness of the organic light-emitting layer, an organic EL device that emits light from a pixel in a desired luminance state can be manufactured. Therefore, the productivity of the organic EL device can be improved.

The desired flatness is set based on the relationship between the flatness defined by the above formula (1) and the luminance distribution ratio in the luminance distribution ratio calculation pixel for the luminance distribution ratio calculation pixel; the luminance distribution ratio In the luminance distribution rate calculation pixel, the ratio of the area of the region having the luminance of 70% or more of the maximum luminance among the areas of the luminance distribution ratio calculation pixels is used.

By the relationship between the flatness and the luminance distribution ratio, the flatness of the organic light-emitting layer is formed to a desired value or more, and a desired luminance distribution ratio can be achieved.

The above desired flatness is 70%, preferably 80%.

Further, the method further includes the step of forming an organic structure including at least one organic layer on the first electrode of the substrate to which the bank is attached. In this case, in the step of forming the organic light-emitting layer, the organic light-emitting layer may be formed on the organic structure.

In the aspect of the step of forming the organic light-emitting layer, in the step of calculating the flatness, the thickness of the organic structure is formed from the thickness of the organic structure and the thickness of the layered body in which the organic light-emitting layer is formed on the organic structure. The thickness distribution of the organic light-emitting layer is calculated by the difference in distribution, and the flatness can be calculated from the thickness distribution of the organic light-emitting layer.

An organic EL device according to another aspect of the present invention includes: (A) a substrate having a substrate, a bank for defining a pixel provided on the substrate, and (B) a substrate disposed on the pixel region corresponding to the pixel in the substrate a substrate to which a 1 electrode is attached, (C) an organic light-emitting layer provided on the first electrode, and (D) a second electrode provided on the organic light-emitting layer; and a minimum thickness of the organic light-emitting layer is d ( The area of the organic light-emitting layer having a (d+determined value) nm or less when viewed from the thickness direction of the substrate is A1, the area of the pixel region is A2, and the flatness of the organic light-emitting layer is (A1). When /A2) × 100 [%], the above flatness is 70% or more.

From the relationship between the flatness and the luminance distribution ratio found by the inventors of the present application, in the organic EL device, the luminance distribution ratio in accordance with the flatness of 70% or more can be achieved. This organic EL device can be produced by the above-described method of manufacturing an organic EL device. In order to achieve productivity improvements.

The predetermined value may be, for example, 2 or more and 15 or less. The above predetermined value can be 10.

According to the present invention, it is possible to provide a method for producing an organic EL device and an organic EL device which can improve productivity.

1‧‧‧Organic EL device

2‧‧ ‧ pixels

2a‧‧‧pixel area

2B‧‧‧Blue pixels

2G‧‧‧Green pixels

2R‧‧‧ red pixels

3‧‧‧Intermediate structures

10‧‧‧Substrate with dam

11‧‧‧Substrate

11a‧‧‧ surface

12‧‧‧Anode (1st electrode)

13‧‧‧dike

13a, 13b‧‧‧ side

14‧‧‧ recess

20‧‧‧Organic EL Construction Department

21‧‧‧ hole injection layer

22‧‧‧ hole transport layer

23‧‧‧Organic light-emitting layer

23B‧‧‧Blue light layer

23G‧‧‧Green light layer

23R‧‧‧Red light layer

30‧‧‧ cathode

40‧‧‧Organic structures

41‧‧‧Layered body

E1 to E14‧‧‧Experimental examples

S10, S12, S14, S16, S18, S20‧‧ steps

Fig. 1 is a plan view showing an organic EL device of an embodiment viewed from a substrate side of a bank.

Fig. 2 is an enlarged view of a portion of the cross section taken along line II-II of Fig. 1.

Fig. 3 is a view showing the substrate of the bank attached to the organic EL device of Fig. 1.

Fig. 4 is a flow chart showing an example of a method of manufacturing an organic EL device according to an embodiment.

Fig. 5 is a view for explaining the steps of forming an organic structure.

Fig. 6 is a view for explaining the steps of the organic light-emitting layer forming step.

Fig. 7 is a schematic view for explaining the relationship between the drying speed and the thickness distribution of the organic light-emitting layer.

Fig. 8 is a view schematically showing the configuration of the organic EL device of the embodiment, Fig. 8(a) schematically showing the constitution of the organic EL devices of Experimental Examples 1 to 4, and Fig. 8(b) schematically showing Experimental Example 5 to The configuration of the organic EL device of 9 and the structure of the organic EL device of Experimental Examples 10 to 14 are schematically shown in Fig. 8(c).

Fig. 9 is a view showing the experimental results of Experimental Examples 1 to 14.

Fig. 10 is a view showing the thickness distribution of the organic light-emitting layers of Experimental Examples 1 to 4.

Fig. 11 is a view showing the thickness distribution of the organic light-emitting layers of Experimental Examples 5 to 9.

Fig. 12 is a view showing the thickness distribution of the organic light-emitting layers of Experimental Examples 10 to 14.

Embodiments of the present invention will be described below with reference to the drawings. The same symbol is attached to the same element. Duplicate descriptions are omitted. The size ratio of the drawing is not necessarily consistent with the description.

The organic electroluminescence (organic EL) device 1 shown in Fig. 1 has a plurality of pixels 2 because of an organic EL display panel. Each pixel 2 is an organic EL element portion. In other words, the organic EL device 1 has a configuration in which a plurality of organic EL element portions are integrally connected. In the present embodiment, the term "pixel" means a minimum unit (or a minimum area) in which light is emitted, and the pixel 2 has color information by the light emission of the pixel 2. In Fig. 1, the pixel 2 is schematically shown by a broken line.

Each of the plurality of pixels 2 emits light of any one of red, green, and blue. From this point of view, the organic EL device 1 has three kinds of pixels 2, that is, a red pixel 2R that emits red light, a green pixel 2G that emits green light, and a blue pixel 2B that emits blue light. Hereinafter, when the color of the light emitted by the pixel 2 is distinguished, the pixel 2 may be referred to as a red pixel 2R, a green pixel 2G, and a blue pixel as described above. 2B.

The plurality of pixels 2 are arranged in a two-dimensional arrangement (or matrix). The two directions orthogonal to each other in the two-dimensional arrangement are also referred to as an X direction (or column direction) and a Y direction (or a row direction). In this case, the red pixel 2R, the green pixel 2G, and the blue pixel 2B constituting three types of the plurality of pixels 2 are, for example, in the Y direction by the following lines (i), (ii), and (iii). The configuration is repeated and the configurations are arranged separately.

(i) A row in which the red pixels 2R are arranged at a predetermined interval in the X direction.

(ii) The green pixel 2G is arranged in the X direction at a predetermined interval.

(iii) A row in which the blue pixels 2B are arranged at a predetermined interval in the X direction.

The organic EL device 1 is, for example, a side-by-side red pixel 2R, a green pixel 2G, and a blue pixel 2B as one display pixel unit, and by controlling the red pixel 2R, the green pixel 2G, and the blue pixel 2B included in the display pixel unit, Full color display is available.

The interval between the pixels 2 in each row, the interval between the pixels 2 in each column, the arrangement example of the pixels 2, and the number of the pixels 2 can be appropriately set in accordance with the specifications of the organic EL device 1.

Next, the configuration of the organic EL device 1 will be described in detail. The organic EL device 1 includes a substrate 10 with a bank, a plurality of organic EL structures 20, and a cathode (second electrode) 30. The organic EL device 1 may be a top emission type device or a bottom emission type device. Hereinafter, unless otherwise stated, the bottom emission type, that is, the case where light is taken from the side of the substrate 10 to which the bank is attached, will be described.

As shown in FIGS. 2 and 3, the substrate 10 having the bank has a substrate 11, a plurality of anodes (first electrodes) 12, and a bank 13. 3 is a view corresponding to a partial enlarged view of a cross section of the substrate 10 along the line II-II in FIG. 1 , and FIG. 2 corresponds to a configuration other than the substrate 10 omitting the bank. The surface of the element.

The substrate 11 is a plate-shaped transparent member that is translucent with respect to visible light (light having a wavelength of 400 nm to 800 nm). The substrate 11 is a support for supporting the anode 12 and the bank 13. An example of the thickness of the substrate 11 is 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 system board, or a flexible substrate such as a plastic substrate or a polymer film. The organic EL device 1 can be made flexible by using a flexible substrate.

On the substrate 11, a circuit for driving each of the pixels 2 can be formed in advance. On the substrate 11, for example, a TFT (Thin Film Transistor), a capacitor, or the like can be formed in advance.

A plurality of anodes 12 are provided on the surface 11a of the substrate 11 on the pixel region 2a corresponding to each of the pixels 2. Examples of the shape of the anode 12 viewed in a plan view (the shape viewed from the thickness direction of the substrate 11) include a square shape of a rectangle and a square, and other polygonal shapes. The shape of the anode 12 viewed from above may be circular or elliptical.

As the anode 12, a film made of a metal oxide, a metal sulfide, a metal, or the like can be used. Specifically, indium tin oxide, zinc oxide, tin oxide, indium tin oxide (ITO) can be used. Indium Zinc Oxide (abbreviated as IZO), gold, platinum, silver and copper The film formed by the film. As described in the present embodiment, when the organic EL device 1 emits light from the substrate 10 side of the bank, the anode 12 exhibiting light transmittance is used.

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

In one embodiment, a layer made of an insulating layer or the like may be provided between the anode 12 and the substrate 11. A layer such as an insulating layer may also be regarded as a part of the substrate 11.

As shown in FIGS. 2 and 3, the bank 13 is provided around each anode 12. The dike 13 can also be disposed to cover the adjacent anodes 12. A part of the bank 13 can be covered on the peripheral portion of the anode 12. The bank 13 is a partition wall that partitions the pixel 2 or the pixel region 2a. That is, the bank 13 is provided on the substrate 11 on the surface 11a of the substrate 11 in a pattern having an opening which is divided by the pixel region 2a which is set in advance. In the present embodiment, as shown in Fig. 1, since a plurality of pixels 2 are arranged in two-dimensional arrangement, they are provided on the bank 13 having a grid-like shape.

An example of the material of the bank 13 is a resin. The bank 13 is, for example, a cured product of a photosensitive resin composition containing a liquid repellent. Examples of the liquid-repellent agent include a liquid-repellent containing a fluororesin. The organic layer of the organic light-emitting layer 23 is formed by a coating method on the pixel region 2a defined by the bank 13 as will be described later. Therefore, the bank 13 is generally formed in such a manner as to have characteristics (e.g., wettability) which can preferably form the organic layer when the organic layer is formed on the pixel region 2a defined by the bank 13 by a coating method. to make.

The shape and the arrangement of the bank 13 can be appropriately set in accordance with the specifications of the organic EL device 1 such as the number of pixels 2 and the resolution, ease of manufacture, and the like. For example, in FIGS. 2 and 3, the side surface 13a of the bank 13 facing the pixel region 2a is substantially orthogonal to the surface 11a of the substrate 11. However, the side surface 13a may be inclined at an acute angle or inclined to an obtuse angle with respect to the surface 11a. When the side surface 13a and the surface 11a are at an acute angle, the shape of the bank 13 is a straight shape, and when the side surface 13a and the surface 11a are obtuse, the shape of the bank 13 is a reverse cone shape. An example of the thickness (height) of the bank 13 is about 0.3 μm to 5 μm.

The substrate 10 to which the bank is attached is formed, for example, by forming the anode 12 on a plurality of pixel regions 2a set in advance on the substrate 11, and then forming the bank 13.

The anode 12 can be formed by an evaporation method or a coating method. When formed by a vapor deposition method, a layer composed of a material of the anode 12 can be formed on the substrate 11, and the layer can be formed into a pattern of a plurality of anodes 12. When it is formed by a coating method, the coating liquid containing the material of the anode 12 is applied onto the substrate 11 in a pattern corresponding to the plurality of anodes 12, and then the coating film is dried. Alternatively, a coating film made of a material to be the anode 12 is formed on the substrate 11 and dried, and then formed into a pattern of the anode 12.

When the coating method is used for forming the anode 12, an example of the coating method may be an inkjet printing method, and other known coating methods such as a slit coating method, a micro gravure coating method, a gravure coating method, and a rod may be used. Coating method, roll coating method, wire bar coating method, spray coating method, screen printing method, quick-drying printing method, lithography method, nozzle printing method, and the like. The solvent of the coating liquid containing the material of the anode 12 may be any solvent that can dissolve the material of the anode 12.

The bank 13 can be formed, for example, by a coating method. Specifically, the coating liquid containing the material of the bank 13 is applied to the substrate 11 on which the anode 12 is formed, and the formed coating film is dried, and then the coating film is formed into a predetermined pattern. Examples of the coating method include a spin coating method, a slit coating method, and the like. The solvent containing the coating liquid of the bank 13 may be any solvent which can dissolve the material of the bank 13.

As shown in Fig. 2, a plurality of organic EL structure portions 20 are provided in the substrate 10 with the banks 13 and recesses 14 (see Figs. 2 and 3) formed by the banks 13 and the anodes 12. The organic EL structure portion 20 includes a hole injection layer 21, a hole transport layer 22, and an organic light-emitting layer 23.

The hole injection layer 21 is an organic layer having a function of improving the efficiency of injection of holes from the anode 12 to the organic light-emitting layer 23. Examples of the material of the hole injection layer 21 include oxides such as vanadium oxide, molybdenum oxide, cerium oxide, and aluminum oxide, phenylamine compounds, starburst amine compounds, phthalocyanine compounds, and amorphous carbon. , polyaniline, and polythiophene derivatives such as polyethylene dioxythiophene (PEDOT).

The thickness of the hole injection layer 21 varies depending on the material to be used, and can be appropriately determined in consideration of the required characteristics and the ease of formation of the layer. The thickness of the hole injection layer 21 is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm.

The hole injection layer 21 may be provided depending on the type of the pixel 2, that is, the red pixel 2R, the green pixel 2G, and the blue pixel 2B, depending on the material or thickness. From the viewpoint of the simplicity of the step of forming the hole injection layer 21, all of the hole injection layers 21 can be formed of the same material and the same thickness.

The hole transport layer 22 is a layer having a function of improving hole injection from the anode 12, the hole injection layer 21 or the hole transport layer 22 of the anode 12 to the organic light-emitting layer 23. As the material of the hole transport layer 22, a generally known hole transport material can be used. The hole transporting material may, for example, be a polyvinyl carbazole or a derivative thereof, a polydecane or a derivative thereof, a polyoxyalkylene having an aromatic amine in a side chain or a main chain or a derivative thereof, or a pyrazoline or a derivative thereof. Or an aromatic amine or a derivative thereof, diphenylethylene or a derivative thereof, triphenyldiamine or a derivative thereof, polyaniline or a derivative thereof, polythiophene or a derivative thereof, polyarylamine or a derivative thereof, Polypyrrole or a derivative thereof, poly(p-styrene) or a derivative thereof, or poly(2,5-thiopheneethylene) or a derivative thereof. Further, a hole transport layer material disclosed in Japanese Laid-Open Patent Publication No. 2012-144722 is also mentioned.

The thickness of the hole transport layer 22 is different depending on the material to be used, and the optimum value can be appropriately set so that the driving voltage and the luminous efficiency are appropriate values. The thickness of the hole transport layer 22 is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm.

The hole transport layer 22 may be provided depending on the type of the pixel 2, that is, the red pixel 2R, the green pixel 2G, and the blue pixel 2B, depending on the material or thickness. From the hole transport layer 22 From the viewpoint of the simplicity of the forming step, all of the hole transport layers 22 can be formed of the same material and the same thickness.

The organic light-emitting layer 23 is provided on the hole transport layer 22. The organic light-emitting layer 23 is an organic layer having a function of emitting light of a predetermined wavelength. The organic light-emitting layer 23 is generally formed mainly of an organic material that emits fluorescence and/or phosphorescence, or a dopant that assists the organic substance. The dopant is added, for example, to increase the luminous efficiency or to change the wavelength of light. The organic substance contained in the organic light-emitting layer 23 may be a low molecular compound or a high molecular compound. Examples of the light-emitting material constituting the organic light-emitting layer 23 include the following pigment-based materials, metal-based compound materials, polymer-based materials, and dopant materials.

Examples of the pigment-based luminescent material include cyclopentylmethylamine or a derivative thereof, tetraphenylbutadiene or a derivative thereof, triphenylamine or a derivative thereof, An oxadiazole or a derivative thereof, a pyrazoloquinoline derivative, a stilbene benzene or a derivative thereof, a stilbene aroma or a derivative thereof, a pyrrole or a derivative thereof, a thiophene ring compound, a pyridine ring compound, an anthrone or an oxime a derivative thereof, hydrazine or a derivative thereof, oligothiophene or a derivative thereof, an oxy group An oxadiazole dimer or a derivative thereof, a pyrazoline dimer or a derivative thereof, a quinacridone or a derivative thereof, a coumarin or a derivative thereof, and the like.

Examples of the metal complex-based light-emitting material include rare earth metals such as Tb, Eu, and Dy, and Al, Zn, Be, Pt, and Ir as center metals, and have a ligand at the ligand. A metal complex of an oxadiazole, a thiadiazole, a phenylpyridine, a phenylbenzimidazole, a quinoline structure or the like. The metal complex compound may, for example, be a metal complex having luminescence from triplet excitation, such as a ruthenium complex or a platinum complex, an aluminum quinoline complex, a quinacridol complex, or a zinc benzene. and A azole complex, a zinc benzothiazole complex, a zinc azomethyl complex, a zinc porphyrin complex, a phenanthroline complex, and the like.

Examples of the polymer-based luminescent material include polyparaphenylene or a derivative thereof, polythiophene or a derivative thereof, polyparaphenylene or a derivative thereof, polydecane or a derivative thereof, polyacetylene or a derivative thereof, Polyfluorene or a derivative thereof, polyvinylcarbazole or a derivative thereof, and a material for polymerizing the above-mentioned pigment material or metal complex material.

Among the above-mentioned luminescent materials, a material that emits red light (hereinafter referred to as "red luminescent material") may, for example, be coumarin or the derivative, thiophene or a derivative thereof, and such a polymer, poly-p-stene styrene. Or a derivative thereof, polythiophene or a derivative thereof, polyfluorene or a derivative thereof, or the like. Among them, polyparaphenylene styrene or a derivative thereof, polythiophene or a derivative thereof, polyfluorene or a derivative thereof, or the like, which is a polymer material, is preferable. The red luminescent material may also be a material disclosed in Japanese Laid-Open Patent Publication No. 2011-105701.

A material that emits green light (hereinafter referred to as "green light-emitting material") may, for example, be a quinacridone or a derivative thereof, a coumarin or a derivative thereof, and a polymer such as poly(p-stirene) or Derivatives, polyfluorene or its derivatives. Among them, polyparaphenylene or a derivative thereof, a polyfluorene or a derivative thereof of a polymer material is preferred. The material disclosed in Japanese Laid-Open Patent Publication No. 2012-036388 is also exemplified as the green luminescent material.

A material that emits blue light (hereinafter referred to as "blue luminescent material"), and examples thereof include stilbene arylene or the derivative, Diazole or the derivative, and such polymers, polyvinylcarbazole or a derivative thereof, polyparaphenylene or a derivative thereof, polyfluorene or a derivative thereof, and the like. Among them, polyvinylcarbazole or a derivative of the polymer material, polyparaphenylene or the derivative, and polyfluorene or the derivative are preferable. The blue luminescent material may also be a material disclosed in Japanese Laid-Open Patent Publication No. 2012-144722.

Examples of the dopant material include hydrazine or a derivative thereof, coumarin or a derivative thereof, erythritol or a derivative thereof, quinacridone or a derivative thereof, Squalium or a derivative thereof, Porphyrin or a derivative thereof, a styryl dye, a tetracene or a derivative thereof, a pyrazolone or a derivative thereof, decacycloolefin or a derivative thereof, phenanthrene Ketone or its derivatives.

The organic light-emitting layer 23 can be disposed in response to different types of the pixels 2, that is, in response to the red pixel 2R, the green pixel 2G, and the blue pixel 2B. On the hole transport layer 22 corresponding to the concave portion 14 of the red pixel 2R, an organic light-emitting layer 23 that emits red light is disposed, and on the hole injection layer 21 corresponding to the concave portion 14 of the green pixel 2G, green light is emitted. The organic light-emitting layer 23 is provided with an organic light-emitting layer 23 that emits blue light on the hole transport layer 22 corresponding to the concave portion 14 of the blue pixel 2B. Hereinafter, the organic light-emitting layer 23 included in the red pixel 2R, the green pixel 2G, and the blue pixel 2B may be referred to as a red light-emitting layer 23R, a green light-emitting layer 23G, and a blue light-emitting layer 23B.

The cathode 30 is provided on the organic light-emitting layer 23. The material of the cathode 30 is preferably a material having a small work function, easy electron injection into the organic light-emitting layer 23, and high electrical conductivity. Further, as described in the present embodiment, when the organic EL device 1 picks up light from the anode 12 side, in order to reflect the light emitted from the organic light-emitting layer 23 to the anode 12 side by the cathode 30, the material of the cathode 30 is preferably A material with high visible light reflectance. Cathode 30, for example, can be used Alkali metals, alkaline earth metals, transition metals, and Group 13 metals of the periodic table. Further, as the cathode 30, a transparent conductive electrode made of a conductive metal oxide, a conductive organic substance or the like may be used.

The thickness of the cathode 30 can be appropriately set in consideration of electrical conductivity and durability. The thickness of the cathode 30 is, for example, 10 nm to 10 μm, preferably 20 nm to 1 μm, more preferably 50 nm to 500 nm.

In the present embodiment, the cathode 30 is formed over the entire display area in which a plurality of pixels 2 are provided. That is, the cathode 30 is formed not only on the organic light-emitting layer 23 but also on the bank 13, and is provided as the anode 12 common to the plurality of pixels 2.

The cathode 30 is provided on the organic light-emitting layer 23, but for example, a specific inorganic layer may be provided between the organic light-emitting layer 23 and the cathode 30 provided above.

Although not shown in the drawings in FIGS. 1 and 2, a sealing substrate is usually provided on the cathode 30 of the organic EL device 1. Further, the organic EL device 1 can have, for example, a generally known configuration of an organic EL panel display panel.

In the organic EL device 1 having the above configuration, the structure in each pixel 2, that is, the portion of the pixel region 2a in the substrate 11, the anode 12, the organic EL structure portion 20, and the portion of the pixel region 2a in the cathode 30 constitute an organic EL component part. Therefore, the organic EL device 1 has a configuration in which a plurality of organic EL element portions partitioned by the bank 13 are integrally connected by the substrate 11 and the anode 12 in common.

In the organic EL device 1, as shown in FIG. 2, the pixel is used The organic light-emitting layer 23 in the second light-emitting layer 23, that is, the organic light-emitting layer 23 in the concave portion 14 has a minimum thickness of d (nm), and is an organic light-emitting layer of (d + predetermined value) [nm] or less when viewed from the thickness direction of the substrate 11. When the area of 23 is A1 and the pixel area is A2, and the flatness α (%) of the organic light-emitting layer 23 is expressed by the following formula (1), the flatness α is 70% or more.

α=(A1/A2)×100‧‧‧(1)

The pixel area is the area of the pixel region 2a, and is also the area of the region of the bank 13 that is separated by the end portion 13b facing the pixel region 2a (refer to FIGS. 2 and 3). The predetermined value (nm) is preferably 2 or more and 15 or less. If it is this range, the flatness can be evaluated more easily and appropriately. The above predetermined value is particularly preferably 5 or more and 12 or less, and may be, for example, 10.

In each of the layers of the red light-emitting layer 23R, the green light-emitting layer 23G, and the blue light-emitting layer 23B, the minimum thickness d (nm) may be different. At this time, the flatness α of each of the red light-emitting layer 23R, the green light-emitting layer 23G, and the blue light-emitting layer 23B of the organic EL device 1 is 70% or more.

Next, a method of manufacturing the organic EL device 1 will be described. Here, a method of manufacturing the organic EL device 1 after the substrate 10 having the bank is prepared will be described. As shown in FIG. 4, the method of manufacturing the organic EL device 1 includes a step of forming the organic structure 40 (organic structure forming step) S10, a step of forming the organic light-emitting layer 23 (organic light-emitting layer forming step) S12, The step (flatness calculation step) S14 of calculating the flatness α of the organic light-emitting layer 23, the step (determination step) S16 for determining whether or not the flatness α is equal to or greater than the desired value, and the step (cathode formation step) S18 for forming the cathode 30 are performed.

When manufacturing the organic EL device 1, first, a mechanism is implemented. The formation step S10 is formed. In the organic structure forming step S10, as shown in FIG. 5, in the pixel region 2a, in other words, on the anode 12 provided in the concave portion 14, the hole injection layer 21 and the hole transport are sequentially formed by the coating method. The layer 22 is used to form the organic structure 40 of the laminate of the hole injection layer 21 and the hole transport layer 22.

Specifically, on the anode 12 of the concave portion 14, a coating containing a hole injecting material is dropped to form a coating film, and then the coating film is dried to form a hole injection layer 21.

The coating method is, for example, an inkjet printing method. However, as long as it is a coating method capable of forming a layer in the concave portion 14, it may be another commonly known coating method, and for example, a micro gravure coating method, a gravure coating method, a bar coating method, a roll coating method, or a bar coating method may be used. The method, the spray coating method, the screen printing method, the quick-drying printing method, the lithographic printing method, and the nozzle printing method are preferably a screen printing method, a quick-drying printing method, a lithographic printing method, and a nozzle printing method.

The solvent to be used for the coating liquid is not particularly limited as long as it is a soluble hole injecting material, and examples thereof include a chloride solvent such as chloroform, methyl chloride or dichloroethane; an ether solvent such as tetrahydrofuran; and toluene. An aromatic hydrocarbon solvent such as xylene; a ketone solvent such as acetone or methyl ketone; an ester solvent such as ethyl acetate, butyl acetate or ethyl cellosolve acetate.

The method of drying the coating film is not particularly limited as long as it can dry the coating film, and examples thereof include vacuum drying, heat drying, and the like.

Then, the coating containing the hole transporting material is dropped onto the hole injection layer 21 in the recess 14 to form a coating film, and then coated. The film is dried to form the hole transport layer 22. Examples of the solvent and the drying method may be the same as those in the hole injection layer 21.

The structure obtained by the organic structure forming step S10, that is, the structure including the substrate 10 having the bank and the organic structure 40 formed in the recess 14 is referred to as the intermediate structure 3. In the organic structure forming step S10, two intermediate structures 3 are produced, and the thickness distribution of the organic structures 40 included in one of the intermediate structures 3 is measured in advance to obtain the thickness of the organic light-emitting layer 23.

As shown in FIG. 4, after the organic structure forming step S10 is performed, the organic light-emitting layer forming step S12 is performed. In the organic light-emitting layer forming step S12, as shown in Fig. 6, the organic light-emitting layer 23 is formed on the organic structure 40 by a coating method. Specifically, after the coating containing the luminescent material to be the organic light-emitting layer 23 is dropped into the concave portion 14 to form a coating film (coating film forming step), the coating film is dried (drying step) to form an organic film. Light-emitting layer 23. The red light-emitting layer 23R and the green light are used in the concave portion 14 corresponding to the red pixel 2R, the green pixel 2G, and the blue pixel 2B, respectively, using a coating liquid containing a red light-emitting material, a green light-emitting material, and a blue light-emitting material. The light emitting layer 23G and the blue light emitting layer 23B.

The coating method may, for example, be an inkjet printing method, or may be any other known coating method exemplified when the hole injection layer 21 is used. The solvent used for the coating liquid may be the same as the solvent exemplified when the hole injection layer 21 is formed as long as it can dissolve the luminescent material.

The drying method of the coating film is the same as that in the case of the hole injection layer 21, and it is not particularly limited as long as the coating film can be dried. Vacuum drying, heat drying and the like are mentioned.

In the organic light-emitting layer forming step S12, the layered body 41 composed of the organic structure 40 and the organic light-emitting layer 23 is formed on the anode 12 in the recess portion 14.

In the organic light-emitting layer forming step S12, the organic light-emitting layer 23 is formed on the organic structure 40 included in each of the two intermediate structures 3 produced in the organic structure forming step S10. Then, the thickness of the layered body 41 formed on the intermediate structure 3 used for measuring the thickness of the organic structure 40 is measured, and the thickness distribution of the layered body 41 is obtained.

As shown in FIG. 4, after the organic light-emitting layer forming step S12 is performed, the flatness calculating step S14 is performed. In the flatness calculation step S14, the thickness distribution of the organic light-emitting layer 23 is first calculated. Specifically, the thickness distribution of the organic structure 40 obtained in the organic structure forming step S10 and the thickness distribution of the layered body 41 obtained in the organic light-emitting layer forming step S12 are calculated, and the thickness distribution of the organic light-emitting layer 23 is calculated. In other words, when viewed from the thickness direction of the substrate 11, the difference from the thickness of the organic structure 40 is calculated from the thickness of the laminated body 41 at each position in the concave portion 14, and the thickness distribution of the organic light-emitting layer 23 is obtained. Next, the flatness α is calculated by using the calculated thickness distribution of the organic light-emitting layer 23 and the formula (1).

As shown in FIG. 4, after the flatness calculation step S14 is performed, the determination step S16 is performed. In the determination step S16, it is determined whether or not the flatness α is equal to or greater than a desired value. In the present embodiment, the "expected value" is 70%. At this time, in the red light-emitting layer 23R, the green light-emitting layer 23G, and the blue light-emitting layer 23B, when the flatness α is different, the red light-emitting layer 23R and the green light are emitted. The value of the minimum flatness α in the flatness α in the layer 23G and the blue light-emitting layer 23B is determined. The flatness α of the plurality of organic light-emitting layers 23 corresponding to the same color (red, green, or blue) can be regarded as the same flatness α because the conditions for forming the material of the coating liquid and the like are the same. Therefore, for example, the flatness α of one organic light-emitting layer 23 can be calculated with respect to one color. However, as in the case of different colors, a plurality of organic light-emitting layers 23 may be sampled, and the smallest flatness α among them may be used for the determination.

In the determination step S16, when the flatness α is 70% (expected value) or more (in the case of "Yes" in S16 of FIG. 4), the step of forming the cathode 30 on the organic light-emitting layer 23 (cathode forming step) S18 is performed. . The method of forming the cathode 30 is, for example, the same vapor deposition method and coating method as in the case of the anode 12. In this step, the cathode 30 is formed on the organic light-emitting layer 23 formed on the plurality of recesses 14. Thereby, the organic EL device 1 shown in Figs. 1 and 2 can be obtained.

In the determination step S16, when the flatness α is less than 70% (expected value) (in the case of "No" in S16 of FIG. 4), the step (formation condition changing step) S20 of changing the formation conditions of the organic light-emitting layer 23 is performed. For example, in the organic light-emitting layer forming step S12, the drying rate in the step of drying the coating film formed by dropping the light-emitting material into the concave portion 14 by the coating method is used.

Here, the relationship between the drying speed and the thickness distribution of the organic light-emitting layer will be described using FIG. In Fig. 7, the relationship between the drying speed and the thickness distribution of the organic light-emitting layer is schematically shown. Specifically, it shows an example of the thickness distribution when the drying speed is increased, and when the drying speed is lowered. An example of the thickness distribution and an example of the thickness distribution between these. Among the above three thickness distributions, the horizontal axis represents the position on the cross section of the recessed portion 14, and x1 and x2 respectively indicate the positions of the side faces 13a and 13a of the bank 13 of the partition recessed portion 14. Among the above three thickness distributions, the vertical axis represents the thickness.

According to the findings of the inventors of the present application, when the drying speed is fast, as shown by the thickness distribution on the left side in Fig. 7, the thickness of the central portion of the organic light-emitting layer 23 is thin and easily becomes concave, and the drying speed is slow. In the case where the thickness distribution on the right side in Fig. 7 is intended to be displayed, the thickness of the central portion of the organic light-emitting layer 23 is increased to be convex. Therefore, according to the thickness distribution of the organic light-emitting layer 23 used in the determination step S16, by adjusting the drying speed, the thickness distribution of the organic light-emitting layer 23 can be adjusted to achieve the thickness distribution as shown in the left side of FIG. The thickness of the central portion of the organic light-emitting layer 23 is reduced to be concave, and when the drying speed is slow, the organic light-emitting layer 23 having a flat thickness distribution as shown in the center of FIG. 7 has a thickness distribution.

In addition, as a parameter which can be changed in the formation conditions of the organic light-emitting layer 23, the composition ratio of the coating liquid, etc. are mentioned, for example.

After the formation condition changing step S20 is performed, the organic light-emitting layer 23 is formed again under the changed formation conditions. In the fourth embodiment, as an example, the case where the organic light-emitting layer forming step S12 is returned after the formation condition changing step S20 can be exemplified. According to this flowchart, a plurality of intermediate structures 3 can be prepared in advance in the organic structure forming step S10, and the organic light-emitting layer forming step S12 can be returned, and then the organic structure of the intermediate structure 3 in which the organic light-emitting layer 23 is not formed can be organic. On the structure 40, the organic light-emitting layer 23 is formed. can. Alternatively, after the formation condition changing step S20, the organic structure forming step S10 is returned.

The inventors of the present application conducted intensive studies and found that the flatness α of the organic light-emitting layer has a certain relationship with the luminance distribution ratio β. When the pixel (luminance distribution ratio calculation pixel) of the organic EL device for calculating the luminance distribution ratio (or the test) is used to emit light, the maximum luminance of the pixel is set to I _MAX and has (I _MAX × 0.7). The area of the above luminance is A3, and when the pixel area is A4, it is defined by the following formula (II).

β=(A3/A4)×100‧‧‧(II)

The definition of the pixel area A4 is the same as the pixel area A3 in the organic EL device 1 calculated by the luminance distribution ratio β.

The relationship between the flatness α of the organic light-emitting layer and the luminance distribution ratio β is explained in accordance with Experimental Examples 1 to 15. In the description of the experimental examples 1 to 15, the constituent elements corresponding to the constituent elements of the organic EL device 1 are simply given the same reference numerals for explanation. In Experimental Examples 1 to 15, the predetermined value of the area A1 for calculating the flatness α was defined as 10. That is, in Experimental Examples 1 to 15, the area A1 of the organic light-emitting layer 23 of (d + 10) nm or less was used.

In Experimental Examples 1 to 4, the organic EL devices E1 to E4 shown in Fig. 8(a) were produced. That is, the hole injection layer 21, the hole transport layer 22, and the organic light-emitting layer 23 are formed from the anode 12 side in the concave portion 14 of the substrate 10 to which the bank is attached, and the cathode 30 is formed on the organic light-emitting layer 23. The hole injection layer 21, the hole transport layer 22, and the organic light-emitting layer 23 are formed by using an inkjet printing method using a coating liquid corresponding to each layer to form a coating film. It is formed by drying. The organic light-emitting layer 23 in each of the concave portions 14 is a blue light-emitting layer 23B. Therefore, the organic EL devices E1 to E4 are organic EL devices 1 that emit blue light.

The hole injection layer 21, the hole transport layer 22, and the organic light-emitting layer 23 in the organic EL devices E1 to E4 use the same hole injection material, hole transport material, and blue light-emitting material. In the organic EL devices E1 to E4, the composition ratios of the coating liquids when the corresponding hole injection layer 21, the hole transport layer 22, and the organic light-emitting layer 23 are formed are different. In the vacuum drying performed when the organic light-emitting layer 23 of the organic EL devices E1 to E4 is formed, the temperature in the vacuum chamber is 13 ° C to 30 ° C. In the vacuum drying, the drying speed of the coating film is slowed in accordance with the order of the organic EL device E1, the organic EL device E2, the organic EL device E3, and the organic EL device E4.

The flatness α of the organic light-emitting layer 23 which the organic EL devices E1 to E4 have is shown in Table 1. The luminance distribution ratio β when the organic EL devices E1 to E4 emit light under the same conditions is shown in Table 1. The pixel areas A2 and A4 used for the calculation of the flatness α and the luminance distribution ratio β are the same.

In Experimental Examples 5 to 9, the organic EL devices E5 to E9 shown in Fig. 8(b) were produced. The configuration of the organic EL devices E5 to E9 has the same configuration as that of the organic EL devices E1 to E4 except that the green light-emitting layer 23G is used instead of the blue light-emitting layer 23B as the organic light-emitting layer 23. The organic EL devices E5 to E9 are organic EL devices 1 that emit green light. The same applies to the manufacture of the organic EL devices E5 to E9. The hole injection layer 21, the hole transport layer 22, and the organic light-emitting layer 23 are also formed by a liquid-jet printing method using a coating liquid corresponding to each layer to form a coating film, and vacuum drying. In the vacuum drying performed in forming the organic light-emitting layer 23, the temperature in the vacuum chamber is from 13 ° C to 30 ° C.

The hole injection layer 21 and the hole transport layer 22 in the organic EL devices E5 to E9 use the same hole injection material and hole transport material as those of the organic EL devices E1 to E4. In the organic EL devices E5 to E9, the composition ratios of the coating liquids when the hole injection layer 21, the hole transport layer 22, and the organic light-emitting layer 23 are formed are different. In the vacuum drying in the case of forming the organic light-emitting layer 23 of the organic EL devices E5 to E9, the drying speed of the coating film is in accordance with the organic EL device E5, the organic EL device E6, and the organic EL. The order of the device E7, the organic EL device E8, and the organic EL device E9 becomes faster.

The flatness α of the organic light-emitting layer 23 which the organic EL devices E5 to E9 have is shown in Table 2. The luminance distribution ratio β when the organic EL devices E5 to E9 emit light under the same conditions as those of the organic EL devices E1 to E4 is as shown in Table 2. The pixel areas A2 and A4 used for the calculation of the flatness α and the luminance distribution ratio β are the same.

In Experimental Examples 10 to 14, the organic EL devices E10 to E14 shown in Fig. 8(c) were produced. The configuration of the organic EL devices E10 to E14 has the same configuration as that of the organic EL devices E1 to E4 except that the red light-emitting layer 23R is used instead of the blue light-emitting layer 23B as the organic light-emitting layer 23. The organic EL devices E10 to E14 are organic EL devices that emit red light. The hole injection layer 21, the hole transport layer 22, and the organic light-emitting layer 23 (red light-emitting layer 23R) are formed by coating using a coating liquid corresponding to each layer by the inkjet printing method as in the case of the organic EL devices E1 to E4. After the film, it was formed by vacuum drying. In the vacuum drying performed in forming the organic light-emitting layer 23, the temperature in the vacuum chamber is from 13 ° C to 30 ° C.

The hole injection layer 21 and the hole transport layer 22 in the organic EL devices E10 to E14 use the same hole injection material and hole transport material as those of the organic EL devices E1 to E4. In the organic EL devices E10 to E14, the composition ratios of the coating liquids when the hole injection layer 21, the hole transport layer 22, and the organic light-emitting layer 23 are formed are different. In the vacuum drying in the case of forming the organic light-emitting layer 23 of the organic EL devices E10 to E14, the drying speed of the coating film is in accordance with the organic EL device E10, the organic EL device E11, the organic EL device E12, the organic EL device E13, and the organic EL device. The order of E14 is slower.

The flatness α of the organic light-emitting layer 23 which the organic EL devices E10 to E14 have is shown in Table 3. The luminance distribution ratio β when the organic EL devices E10 to E14 emit light under the same conditions as those of the organic EL devices E1 to E4 is as shown in Table 3. The pixel areas A2 and A4 used for the calculation of the flatness α and the luminance distribution ratio β are the same.

Fig. 9 is a graph showing the relationship between the flatness α (%) shown in Tables 1 to 3 and the luminance distribution ratio β (%). In Fig. 9, the horizontal axis represents flat Tan (%), the vertical axis represents the luminance distribution rate (%). In Fig. 9, the points corresponding to the luminance distribution ratios β (%) of the respective values of the flatness α (%) shown in Tables 1 to 3 are plotted, and the same marks (tetragonal and triangular) are used for each color. Wait). Then, the number attached to each symbol indicates the number of the experimental example.

Fig. 10 is a view showing a thickness distribution of the organic light-emitting layer 23 (blue light-emitting layer 23B) of the organic EL devices E1 to E4. Fig. 11 is a view showing a thickness distribution in the concave portion 14 of the organic light-emitting layer 23 (green light-emitting layer 23G) of the organic EL devices E5 to E9. Fig. 12 is a view showing a thickness distribution in the concave portion 14 of the organic light-emitting layer 23 (red light-emitting layer 23R) of the organic EL devices E10 to E14. In Figs. 10 to 12, the horizontal axis represents the position on the cross section of the recessed portion 14, and the positions of x1 and x2 respectively indicate the positions of the side faces 13a and 13a of the bank 13 defining the recessed portion 14. However, the positions of x1 and x2 vary depending on the experimental error and the dot drawing. However, in FIGS. 10 to 12, x1 and x2 are arranged in the vicinity of the positions roughly corresponding to the side faces 13a and 13a. The vertical axes of Figs. 10 to 12 show the thickness of the organic light-emitting layer 23.

From the results shown in Fig. 9, it can be understood that for each of blue, green, and red, the flatness α and the luminance distribution ratio β are substantially linear, that is, corresponding to one to one. Therefore, by determining the flatness α, the luminance distribution ratio β can be adjusted. The materials of the blue light-emitting layer 23B, the green light-emitting layer 23G, and the red light-emitting layer 23R are different. Therefore, the relationship between the flatness α and the luminance distribution ratio β can be satisfied without depending on the material of the organic light-emitting layer 23.

Thus, since the flatness α has a certain relationship with the luminance distribution ratio β, it is explained in the manufacturing method of the organic EL device 1. When the flatness α of the organic light-emitting layer 23 is adjusted, the luminance distribution ratio β can be made constant or higher. For example, when the flatness α is 70% or more, a luminance distribution ratio β of substantially 70% or more can be achieved. Therefore, the thickness of the layer located below the organic light-emitting layer 23 (in the example shown in FIG. 2, the hole injection layer 21 and the hole transport layer 22) is measured, and the layers are formed to be flat in order to flatten the material. The productivity of the organic EL device 1 can be remarkably improved as compared with the case where the manufacturing conditions are adjusted for each layer.

According to the relationship between the flatness α and the luminance distribution ratio β, the luminance distribution ratio β of the organic EL device 1 after the production can be estimated by the evaluation of the flatness α. Therefore, the manufacturing cost of the organic EL device 1 can also be reduced. In this regard, a case is described in which a cathode is formed on the organic light-emitting layer to produce an organic EL device, and then the luminance distribution ratio is measured and fed back to the formation conditions of the organic light-emitting layer.

In order to form a cathode on the organic light-emitting layer to first fabricate an organic EL device, it is necessary to form a cathode on at least the organic light-emitting layer. Therefore, the luminance distribution ratio β of the organic EL device is calculated after the production, and if it is necessary to change the formation conditions of the organic light-emitting layer, the cathode must be formed again. On the other hand, in the manufacturing method of the organic EL device 1, in the stage of forming the organic light-emitting layer 23, the luminance distribution ratio β of the organic EL device 1 can be estimated from the relationship between the flatness α and the luminance distribution ratio β. This result can omit unnecessary cathode formation and seek a reduction in manufacturing cost.

The organic EL device 1 shown in Fig. 1 can be obtained by the production method shown in Fig. 4. Therefore, the configuration of the organic EL device 1 can be configured to contribute to the improvement of productivity. In addition, the organic EL device 1 Since the flatness α of the organic light-emitting layer 23 is 70% or more, the organic EL device 1 can achieve a luminance distribution ratio β of 70% or more.

As described above, when the blue light-emitting layer 23B of the organic EL devices E1 to E4 is formed, the drying speed of the coating film becomes slow in accordance with the order of the organic EL devices E1 to E4. When the green light-emitting layer 23G of the organic EL devices E5 to E9 is formed, the drying speed of the coating film becomes faster in accordance with the order of the organic EL devices E5 to E9. When the red light-emitting layer 23R of the organic EL devices E10 to E14 is formed, the drying speed of the coating film becomes slow in accordance with the order of the organic EL devices E10 to E14. Further, from Fig. 10 to Fig. 12, as shown in Fig. 7, it can be seen that when the drying speed of the coating film to be the organic light-emitting layer 23 is fast, the central portion is formed into a concave shape to form an organic The tendency of the light-emitting layer 23 tends to form the organic light-emitting layer 23 so that the center portion becomes convex as the drying speed of the coating film becomes slow. Therefore, the flatness α of the organic light-emitting layer 23 can be adjusted, for example, by adjusting the drying speed.

The embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit and scope of the invention. For example, a hole injection layer and a hole transport layer are formed between the organic light-emitting layer and the electrode of the substrate on which the bank is attached, but these may not be formed. For example, the organic light-emitting layer may be formed adjacent to the electrode of the substrate to which the bank is attached. Alternatively, the hole transport layer is not formed, and the organic light-emitting layer is formed adjacent to the hole injection layer.

An electron injecting layer may be disposed between the organic light emitting layer and the cathode. The electron injecting layer is a layer having a function of improving electron injection efficiency from the cathode to the organic light emitting layer. The electron injection layer can use generally known electricity Sub-injection material. When the electron injecting layer is provided in this manner, an electron transporting layer may be provided between the electron injecting layer and the organic light emitting layer. The electron transport layer is a layer having a function of improving electron injection from the cathode, the electron injection layer, or the electron transport layer close to the cathode. As the electron transport layer, a generally known electron transport material can be used.

In the description so far, the first electrode of the substrate to which the bank is attached is an anode, and the second electrode is a cathode. However, the first electrode may be a cathode and the second electrode may be an anode. Further, in the above description, the organic EL device has three types of pixels of the red pixel 2R, the green pixel 2G, and the blue pixel 2B. However, the type of the color is not particularly limited, and all of the pixels may emit the same color.

The above description has been made to determine that the expected value in step S16 is 70%, but the above-described expected value is not limited to 70%. It can be set in accordance with the performance required in the organic EL device. The expected value is preferably 70% or more, more than 70% of the desired value, preferably 80%. The example of the organic EL device is not limited to the organic display panel, and may be any organic light-emitting device.

S10, S12, S14, S16, S18, S20‧‧ steps

Claims (10)

A method of manufacturing an organic EL device, comprising: a substrate; a bank provided on the substrate and defining a pixel; and a first electrode provided on a pixel region corresponding to the pixel in the substrate a step of forming an organic light-emitting layer by a coating method on the first electrode of the substrate of the bank, calculating a flatness of the organic light-emitting layer, and determining whether the flatness of the organic light-emitting layer is equal to or higher than a desired flatness And a step of forming a second electrode on the organic light-emitting layer; and in the step of calculating the flatness, the minimum thickness of the organic light-emitting layer is d (nm), and when viewed from the thickness direction of the substrate, (d+ is predetermined) The area of the organic light-emitting layer having a value of nm or less is A1, the area of the pixel region is A2, and when the flatness is α, the flatness is calculated by the following formula (1). When the flatness is equal to or greater than a desired value, the step of forming the second electrode is performed, and in the determining step, when the flatness does not reach a desired value, the shape is The organic light emitting layer in the step of changing the conditions of forming the organic light emitting layer to form the organic light emitting layer, α = (A1 / A2) × 100‧‧‧ (1). The method for producing an organic EL device according to claim 1, wherein the predetermined value is 2 or more and 15 or less. The manufacturer of the organic EL device as described in claim 1 The method wherein the aforementioned value is 10. The method of manufacturing an organic EL device according to any one of claims 1 to 3, wherein the desired flatness is based on a flatness defined by the above formula (1) with respect to a luminance distribution ratio calculation pixel. In the luminance distribution ratio calculation pixel, the luminance distribution rate calculation pixel has the maximum luminance among the pixels of the luminance distribution ratio calculation pixel. The ratio of the area of the region of brightness of 70% or more. The method for producing an organic EL device according to any one of claims 1 to 4, wherein the aforementioned desired flatness is 70%. The method for producing an organic EL device according to any one of claims 1 to 5, further comprising: forming an organic structure including at least one organic layer on the first electrode of the substrate with the bank a step of forming the organic light-emitting layer on the organic structure in the step of forming the organic light-emitting layer. The method for producing an organic EL device according to claim 6, wherein in the step of calculating the flatness, the organic light-emitting layer is formed from the thickness distribution of the organic structure and the organic structure. The thickness distribution of the organic light-emitting layer is calculated from the difference in thickness distribution of the laminate, and the flatness is calculated from the thickness distribution of the organic light-emitting layer. An organic EL device comprising: a substrate; a substrate provided on the substrate and defining a pixel; and a substrate provided on the substrate with a first electrode corresponding to the first electrode in the pixel region of the pixel, An organic light-emitting layer on the first electrode; and a second electrode provided on the organic light-emitting layer; a minimum thickness of the organic light-emitting layer is d (nm), and is (d + a predetermined value when viewed from a thickness direction of the substrate The area of the organic light-emitting layer of nm or less is A1, the area of the pixel region is A2, and the flatness of the organic light-emitting layer is (A1/A2)×100 [%], and the flatness is 70%. the above. The organic EL device according to claim 8, wherein the predetermined value is 2 or more and 15 or less. The organic EL device according to claim 8, wherein the aforementioned value is 10.