JP2011165629A - Substrate for organic electroluminescent element, organic electroluminescent element, and its manufacturing method - Google Patents

Abstract

The present invention provides an organic layer which can be easily filled with a coating solution for forming an organic layer in a light emitting region provided between partition walls when the organic layer is formed by a printing method, and the cathode can be divided by the partition walls. The main object is to provide a substrate for an EL element.
In the present invention, a substrate, a first electrode layer formed on the substrate, and a substrate formed on the substrate on which the first electrode layer is formed, and dividing the second electrode layer into a plurality of portions. A plurality of insulative partition walls defining a region, and each of the partition walls is composed of a plurality of small partition walls provided in parallel at a predetermined interval. The problem is solved by providing a substrate for an organic electroluminescence element characterized by being in the range of 5 μm to 2 μm.
[Selection] Figure 1

Description

  The present invention relates to a substrate for an organic electroluminescence element having a cathode partition, an organic electroluminescence element, and a method for producing the same.

Conventionally, as a method for producing an organic electroluminescence (hereinafter, electroluminescence may be abbreviated as EL) element, an insulating partition having a reverse taper (reverse trapezoidal) shape is provided on an anode, and an organic layer and A method of dividing the cathode by forming the cathode in order by vapor deposition is known.
However, in the case where a part of the partition wall is missing, or when dust or particles (fine particles) are attached around the partition wall, when the cathode is formed by vapor deposition, the adjacent cathodes across the partition wall form the partition wall. There is a problem of short-circuiting between cathodes that are over-connected and electrically insulated.

  In view of this, a method has been proposed in which a plurality of partition walls are provided side by side between cathodes that are to be electrically insulated to reliably divide the cathodes (see Patent Document 1 and Patent Document 2).

Japanese Patent Laid-Open No. 10-321372 JP 2000-235894 A

  In the above method of providing a partition to divide the cathode, when an organic layer is formed by a printing method instead of an evaporation method, if the width of a light emitting region (pixel) provided between adjacent partition walls is narrow, The organic layer forming coating solution adhering to the plate or the blanket cannot directly contact the substrate, and the organic layer forming coating solution may be difficult to enter. In such a case, the organic layer forming coating solution is not sufficiently filled in the light emitting region, and a desired organic layer may not be formed.

  The present invention has been made in view of the above problems, and when an organic layer is formed by a printing method, a light emitting region provided between adjacent partition walls can be filled with an organic layer forming coating solution. And it aims at providing the board | substrate for organic EL elements which can cut | disconnect a cathode with a partition.

  In order to achieve the above object, in the present invention, a plurality of second electrode layers are formed on a substrate, a first electrode layer formed on the substrate, and a substrate on which the first electrode layer is formed. A plurality of insulating partitions that define a dividing region to be divided into a plurality of regions, and each of the partitions is composed of a plurality of small partitions provided in parallel at a predetermined interval. Is within the range of 0.5 μm to 2 μm.

  According to the present invention, each of the partition walls is composed of a plurality of small partition walls provided in parallel at a predetermined interval, and the height of the small partition walls is within the above range. When the organic layer constituting the organic EL layer is formed on the substrate for printing by a printing method, the organic layer forming coating solution should be in direct contact with the substrate in the light emitting region provided between the adjacent partition walls during printing. Therefore, a desired organic layer can be formed by sufficiently filling the light emitting region with an organic layer forming coating solution. In addition, since there are a plurality of small barrier ribs, when the second electrode layer is further formed on the organic EL layer, the second electrode layer is surely divided and short-circuited between the second electrode layers located across the barrier ribs. It is possible to prevent.

  In the said invention, it is preferable that the width | variety of the light emission area | region provided between the said partition is 60 micrometers or more. This is because the organic layer forming coating solution adhering to the plate or the blanket can come into wide contact with the substrate in the light emitting region, and it becomes easier to fill the organic layer forming coating solution.

  In the said invention, it is preferable that the space | interval between the said small partition walls exists in the range of 1 micrometer-60 micrometers. The organic layer forming coating liquid adhering to the plate or blanket can be prevented from coming into contact with the substrate between the small partition walls, and the organic layer forming coating liquid can be prevented from entering a large amount between the small partition walls. In addition, it is possible to prevent the organic layers from being continuously formed between the tops of the adjacent small partition walls. Thereby, it is possible to reliably divide the second electrode layer and prevent a short circuit between the second electrode layers located with the partition wall interposed therebetween.

  In the said invention, it is preferable that the insulating layer is formed between the said 1st electrode layer and the said partition. This is because when the organic EL element is formed, the first electrode layer and the second electrode layer can be prevented from contacting and short-circuiting.

  Moreover, in this invention, at least among the organic layers which comprise the organic EL element substrate preparation process which prepares the organic EL element substrate mentioned above, and the organic EL layer containing a light emitting layer on the said organic EL element substrate. And an organic layer forming step of forming one organic layer by a printing method.

  According to the present invention, since the organic layer is formed by the printing method on the organic EL element substrate described above, the light emitting region provided between adjacent partition walls is sufficiently filled with the organic layer forming coating solution. A desired organic layer can be formed. Moreover, when the second electrode layer is further formed on the organic EL layer by suppressing a large amount of the organic layer forming coating liquid from entering between the small partition walls, the second electrode layer is reliably divided, It is possible to prevent a short circuit between the second electrode layers located across the partition wall.

In the above invention, the height of the organic layer at the end of the small partition provided on the light emitting region side among the plurality of small partitions constituting the partition of the organic EL element substrate is t. _1, when the light emitting region side of the small partition wall provided in the light emitting region side where the height of the organic layer at the end opposite the t _2, it is preferable that t _1> t ₂ .

  In the said invention, it is preferable to have a 2nd electrode layer formation process which forms a 2nd electrode layer by forming a metal material into a film on the said organic EL layer after the said organic layer formation process. This is because the second electrode layer may have a low resistance, and a metal material is most suitable.

  In the said invention, the film-forming method of the said metal material may be a vacuum evaporation method. This is because the vacuum deposition method is a method that causes little damage to the organic EL layer in a dry process and is suitable for stacking.

  In the said invention, you may use a metal paste as said metal material. This is because the wet process is more suitable for a larger area than the dry process. Even in the wet process, a metal paste containing a solvent that does not affect the organic EL layer can be used.

  Moreover, in this invention, it forms on the 1st electrode layer between the partition for the organic EL element substrate mentioned above, and the said organic EL element substrate, The organic EL layer containing a light emitting layer, On the said organic EL layer An organic EL element comprising: a second electrode layer formed and separated by the partition wall, wherein the second electrode layers adjacent to each other across the partition wall are electrically insulated from each other To do.

  According to the present invention, since the organic EL element substrate described above is used, a desired organic layer is formed by sufficiently filling a light emitting region provided between adjacent partition walls with an organic layer forming coating solution. be able to. In addition, the second electrode layer is surely divided by preventing the organic layer forming coating liquid from entering a large amount between the small partition walls, thereby preventing a short circuit between the second electrode layers located across the partition walls. Is possible.

In the above invention, the height of the second electrode layer at the end of the small partition provided on the light emitting region side among the plurality of small partitions constituting the partition is t ₃ , the light emission when the light emitting region side of the small partition wall provided in the region side where the height of the second electrode layer at the end opposite the t _4, it is preferable that t _3> t _4.

  In the above invention, at least one of the organic layers constituting the organic EL layer may have a meniscus cross-sectional shape. When the organic layer constituting the organic EL layer has a meniscus cross-sectional shape, the thickness of the organic layer is increased around the partition wall, but the second electrode layer is reliably divided by the configuration of the present invention. can do.

  In the present invention, when an organic layer is formed by a printing method, a light emitting region provided between adjacent barrier ribs can be sufficiently filled with a coating liquid for forming an organic layer, and the cathode can be divided by the barrier ribs. There is an effect.

It is a schematic sectional drawing which shows an example of the board | substrate for organic EL elements of this invention. It is a schematic diagram which shows an example of the board | substrate for organic EL elements of this invention. It is a schematic sectional drawing which shows an example of the positional relationship of the blanket and a board | substrate in a light emission area | region. It is a schematic sectional drawing which shows the other example of the positional relationship of the blanket and a board | substrate in a light emission area | region. It is a schematic sectional drawing which shows the other example of the board | substrate for organic EL elements of this invention. It is process drawing which shows an example of the manufacturing method of the organic EL element of this invention. It is a schematic diagram which shows an example of the organic layer formation process in the manufacturing method of the organic EL element of this invention. It is a schematic diagram which shows the other example of the organic layer formation process in the manufacturing method of the organic EL element of this invention. It is process drawing which shows the other example of the manufacturing method of the organic EL element of this invention. It is a schematic diagram which shows the other example of the board | substrate for organic EL elements of this invention. It is process drawing which shows the other example of the manufacturing method of the organic EL element of this invention. It is a schematic diagram which shows an example of the organic layer formation process in the manufacturing method of the organic EL element of this invention. It is a schematic diagram which shows the other example of the organic layer formation process in the manufacturing method of the organic EL element of this invention. It is a schematic sectional drawing which shows an example of the organic EL element of this invention. It is a schematic sectional drawing which shows the other example of the organic EL element of this invention. It is a schematic sectional drawing which shows the other example of the organic EL element of this invention. It is a schematic sectional drawing which shows the other example of the organic EL element of this invention.

  Hereinafter, the substrate for an organic EL element, the organic EL element and the production method thereof of the present invention will be described in detail.

A. First, the organic EL element substrate of the present invention will be described. The organic EL element substrate of the present invention is formed on a substrate, a first electrode layer formed on the substrate, and a substrate on which the first electrode layer is formed, and divides the second electrode layer into a plurality of parts. A plurality of insulating partition walls defining a dividing region, each of the partition walls is composed of a plurality of small partition walls provided in parallel at a predetermined interval, and the height of the small partition wall is It is in the range of 0.5 μm to 2 μm.

  The organic EL element substrate of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of the organic EL element substrate of the present invention. An organic EL element substrate 1 illustrated in FIG. 1 includes a substrate 2, a first electrode layer 3 formed on the substrate 2, an insulating layer 4 formed on the first electrode layer 3, and an insulating layer 4. And a plurality of insulating barrier ribs 5 that divide the second electrode layer into a plurality of dividing regions 10. In the organic EL element substrate 1, each of the partition walls 5 is composed of a plurality of small partition walls 5a and 5b provided in parallel at a predetermined interval d. Further, the height h of the small partition walls 5a and 5b is in the range of 0.5 μm to 2 μm. Since the height h of the small barrier ribs 5a and 5b is as low as within the above range, when the organic layer is formed on the organic EL element substrate 1 by the printing method, the light emitting region 11 provided between the adjacent barrier ribs 5 It becomes easy to fill the organic layer forming coating solution. In the example shown in FIG. 1, as illustrated in FIG. 2, the barrier ribs 5 (small barrier ribs 5a) are arranged so that the stripe pattern of the barrier ribs 5 (small barrier ribs 5a, 5b) is orthogonal to the stripe pattern of the first electrode layer 3. 5b) is formed. FIG. 1 is a cross-sectional view taken along line AA in FIG.

  In the case of the printing method, if the height of the small partition walls is low, the reason why it becomes easier to fill the light emitting region with the organic layer forming coating solution is considered as follows. As illustrated in FIG. 3, when the height h of the small partition walls 5 a and 5 b is low, the organic layer forming coating solution 13 attached to the blanket 12 may come into contact with the surface of the first electrode layer 3 in the light emitting region 11. It is thought that it becomes easy to fill the light emitting region 11 with the organic layer forming coating solution 13. On the other hand, as illustrated in FIG. 4, when the height h of the small partition walls 5 a and 5 b is high, the organic layer forming coating solution 13 attached to the blanket 12 contacts the surface of the first electrode layer 3 in the light emitting region 11. It is thought that it becomes difficult to fill the light emitting region 11 with the organic layer forming coating solution 13.

  According to the present invention, each of the partition walls is composed of a plurality of small partition walls provided in parallel at a predetermined interval, and the height of the small partition walls is within the above range. When an organic layer constituting an organic EL layer is formed on a substrate for printing by a printing method, the organic layer forming coating solution should be in direct contact with the substrate in a light emitting region provided between adjacent partition walls during printing. Therefore, a desired organic layer can be formed by sufficiently filling the light emitting region with an organic layer forming coating solution. Further, the organic layer forming coating liquid is prevented from directly contacting the substrate between the small partition walls, and the organic layer forming coating liquid is prevented from entering a large amount between the small partition walls, thereby further reducing the organic EL layer. When the second electrode layer is formed thereon, it is possible to reliably divide the second electrode layer and prevent a short circuit between the second electrode layers located with the partition wall interposed therebetween.

  The “divided region” is a region where the second electrode layer is divided into a plurality of regions and does not contribute to light emission. This divided region is a region where a partition is provided, and is defined by the partition. On the other hand, the “light emitting region” refers to a region contributing to light emission. This light emitting region is a region provided between adjacent barrier ribs, and barrier ribs are formed at both ends of the light emitting region.

The “interval between the small partition walls” refers to a distance from an end portion of the upper bottom surface to an end portion of the upper bottom surface of adjacent small partition walls in a plurality of small partition walls constituting the partition wall.
In addition, the space | interval between small partitions can be measured with an optical microscope, a laser microscope, and a scanning white interferometer.

  Hereinafter, each structure in the organic EL element substrate of the present invention will be described.

1. Partition Walls In the present invention, a plurality of partition walls are formed on the substrate on which the first electrode layer is formed, and delimits a dividing region that divides the second electrode layer into a plurality of portions. Each of the partition walls is composed of a plurality of small partition walls provided in parallel at a predetermined interval. In the present invention, the height of the small partition wall is in the range of 0.5 μm to 2 μm, preferably in the range of 0.5 μm to 1.5 μm, and more preferably in the range of 0.5 μm to 1 μm. It is more preferable.

  The height of the small partition walls is generally set so that the height from the substrate surface to the surface of the small partition walls is higher than the height from the substrate surface to the second electrode layer surface at the center of the light emitting region. The height of the small partition wall is about 3 μm to 4 μm. When the small partition wall is at such a height, in the direct coating method such as gravure printing, when the width of the light emitting area is narrow, the organic layer forming coating liquid adhering to the plate or blanket contacts the substrate in the light emitting area. And the light emitting region may not be sufficiently filled with the organic layer forming coating solution. On the other hand, in the present invention, by setting the height of the small partition wall as low as within the above range, the organic layer forming coating liquid adhering to the plate or blanket can easily come into contact with the substrate in the light emitting region. In addition, since the light emitting region can be sufficiently filled with the organic layer forming coating solution, a desired organic layer can be formed. If the height of the small partition is too low, the second electrode layer may not be divided.

The width of the light emitting region provided between adjacent partitions may be any width that allows the organic layer forming coating solution attached to the plate or blanket to contact the substrate in the light emitting region.
It is preferably 60 μm or more, and more preferably 100 μm or more. The upper limit is usually about 10 mm in consideration of the pixel size of the target organic EL element. By setting the width of the light emitting region in such a range, the organic layer forming coating liquid adhering to the plate or the blanket can be in wide contact directly with the substrate in the light emitting region, and the organic layer forming This is because it becomes easier to fill the coating liquid. As described above, if the width of the light emitting region is too narrow, the organic layer forming coating solution attached to the plate or blanket cannot directly contact the substrate in the light emitting region. It becomes difficult to fill with liquid.

On the other hand, the interval between the small partition walls may be an interval that can reliably divide the second electrode layer, but is preferably in the range of 1 μm to 60 μm, and is preferably in the range of 1 μm to 30 μm. It is more preferable that it is in the range of 1 μm to 10 μm. If the distance between the small partition walls is too wide, the organic layer forming coating solution adhering to the plate or the blanket will easily come into contact with the surface of the first electrode layer between the small partition walls. This is because it may be difficult to divide the second electrode layer because it easily enters. On the other hand, when the distance between the small partition walls is too narrow, it is difficult to form, or when the distance between the small partition walls is too narrow, the organic layers may be formed continuously between the tops of the adjacent small partition walls. Because there is.
The method for measuring the distance between the small partition walls is as described above.

  When the number of the small partition walls constituting the partition walls is three or more, the intervals between the small partition walls are usually equal.

  The number of the small partition walls constituting the partition wall may be plural, for example, two, three, or the like. If the number of the small partition walls constituting the partition wall is too large, the light emitting region becomes relatively narrow. Therefore, the number of the small partition walls constituting the partition wall is preferably two.

  If the small partition wall has the above height, the second electrode layer can be divided into a plurality of parts. Therefore, the cross-sectional shape of the small partition wall is not particularly limited. Examples include a shape (forward taper shape) and a reverse taper shape. An overhang shape such as a reverse taper shape is preferable.

  In the case of a reverse taper shape, the taper angle θ with respect to the substrate surface may be 0 ° <θ <90 °, preferably 20 ° <θ <80 °, more preferably 30 ° <θ <70 °. In the case of an inversely tapered shape, the taper angle θ refers to the taper angle θ with respect to the surface of the substrate 2 as illustrated in FIG. FIG. 5 is a schematic sectional view showing another example of the organic EL element substrate of the present invention.

  The partition formation position is appropriately selected depending on the driving method and display method of the organic EL element. For example, in the case of a passive organic EL element, since the first electrode layer is usually formed in a stripe pattern, the small barrier ribs constituting the barrier rib are also arranged in a stripe pattern so as to be orthogonal to the stripe pattern of the first electrode layer. Formed. Further, for example, in the case of an area-color organic EL element, the first electrode layer is formed almost entirely on the substrate except the region where the extraction electrode and the like are formed, and the light emitting region is formed by the partition. When partitioning into a desired pattern, the small partition walls constituting the partition walls are formed in a desired pattern, for example, a pattern of pictures or characters.

  The plurality of small partitions constituting the partition need only be provided in parallel at a predetermined interval, and the shape of the small partitions can be linear, curved, or the like.

  The width of the divided region defined by the partition walls is not particularly limited, but is preferably 60 μm or less. This is because if the width of the divided region is within the above range, an effect of suppressing the organic layer forming coating liquid from entering the divided region can be sufficiently ensured. Further, if the width of the divided region is too wide, the light emitting region becomes relatively narrow.

  Examples of the partition wall forming material include photosensitive polyimide resins, acrylic resins, novolac resins, styrene resins, phenol resins, melamine resins, and other photo-curing resins, thermosetting resins, and inorganic materials. Can be mentioned.

  In this case, as a method for forming the partition wall, a general method such as a photolithography method or a printing method can be used.

2. First Electrode Layer The first electrode layer used in the present invention may be an anode or a cathode, but is usually formed as an anode.

  The first electrode layer may or may not have transparency. The transparency of the first electrode layer is appropriately selected depending on the light extraction surface and the like. For example, when light is extracted from the first electrode layer side, the first electrode layer needs to be transparent or translucent.

  As the anode, a conductive material having a high work function is preferably used so that holes can be easily injected. Specifically, a metal having a high work function such as ITO, indium oxide, gold, polyaniline, polyacetylene, poly Examples thereof include conductive polymers such as alkylthiophene derivatives and polysilane derivatives.

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

  The first electrode layer may be formed in a pattern on the substrate, or may be formed on almost the entire surface of the substrate except for the region where the extraction electrode or the like is formed. Usually, the first electrode layer is formed in a pattern on the substrate. When the first electrode layer is formed on almost the entire surface of the substrate except for the region where the extraction electrode or the like is formed, the light emitting region can be partitioned into a desired pattern by the partition.

  As a method for forming the first electrode layer, a general electrode forming method can be used, for example, a PVD method such as a vacuum deposition method, a sputtering method, an ion plating method, a CVD method, or the like. Can do. Further, the patterning method of the first electrode layer is not particularly limited as long as it can be accurately formed into a desired pattern, and specific examples thereof include a photolithography method.

3. Substrate The substrate used in the present invention is not particularly limited as long as it supports the above-described partition walls, the first electrode layer, and the like and has a predetermined strength. In the present invention, when the first electrode layer has a predetermined strength, the first electrode layer may also serve as the substrate. Usually, however, the first electrode layer is formed on the substrate having the predetermined strength. Is formed.

  The substrate is not particularly limited as long as the above partition walls, the first electrode layer, and the like can be formed. For example, the substrate is appropriately determined depending on whether light transmission is necessary depending on the light extraction surface. In general, since it is preferable that the substrate side be a light extraction surface, the substrate is preferably formed of a transparent material.

  Examples of the material for forming such a substrate include soda lime glass, alkali glass, lead alkali glass, borosilicate glass, aluminosilicate glass, and silica glass, or a resin substrate that can be formed into a film. Can be used. The resin used for the resin substrate is preferably a polymer material having relatively high solvent resistance and heat resistance. Specifically, fluorine resin, polyethylene, polypropylene, polyvinyl chloride, polyvinyl fluoride, polystyrene, ABS resin, polyamide, polyacetal, polyester, polycarbonate, modified polyphenylene ether, polysulfone, polyarylate, polyetherimide, polyether mon Phon, Polyamideimide, Polyimide, Polyphenylene sulfide, Liquid crystalline polyester, Polyethylene terephthalate, Polybutylene terephthalate, Polyethylene naphthalate, Polymicroxylene dimethylene terephthalate, Polyoxymethylene, Polyethersulfone, Polyetheretherketone, Polyacrylate, Acrylonitrile -Styrene resin, phenol resin, urea resin, melamine resin, unsaturated polyester resin, Epoxy resins, polyurethanes, silicone resins, amorphous polyolefins, and the like. In addition to the above, any polymer material that satisfies a predetermined condition can be used, and two or more types of copolymers can be used. Furthermore, you may use the board | substrate which has gas barrier property which interrupts | blocks gas, such as a water | moisture content and oxygen, as needed.

4). Insulating layer In the present invention, an insulating layer is preferably formed between the first electrode layer and the partition. This is because when the organic EL element is formed using the organic EL element substrate of the present invention, it is possible to prevent the first electrode layer and the second electrode layer from coming into contact with each other and causing a short circuit. This insulating layer is preferably formed so as to cover the end of the first electrode layer. Since the thickness of the organic EL layer is reduced at the end portion of the first electrode layer, short-circuiting can be made difficult by forming an insulating layer. In addition, it is possible to prevent the adjacent light emitting regions from being electrically connected. The portion where the insulating layer is formed can be a region that does not contribute to light emission.

  Examples of the material for forming the insulating layer include photo-curing resins such as photosensitive polyimide resins and acrylic resins, thermosetting resins, and inorganic materials.

  As a method for forming the insulating layer, a general method such as a photolithography method or a printing method can be used.

5. Substrate for organic EL element As an application of the substrate for organic EL element of the present invention, it is used for forming an organic EL element. At that time, as a method for forming an organic layer constituting the organic EL layer, a printing method is used. Preferably used. Therefore, the organic EL element substrate of the present invention is suitably used for printing.

B. Next, a method for manufacturing the organic EL element of the present invention will be described. The organic EL device manufacturing method of the present invention includes an organic EL device substrate preparation step for preparing the organic EL device substrate described above, and an organic material that constitutes an organic EL layer including a light emitting layer on the organic EL device substrate. An organic layer forming step of forming at least one organic layer of the layers by a printing method.

  The manufacturing method of the organic EL element of this invention is demonstrated referring drawings. FIG. 6 is a process diagram showing an example of a method for producing an organic EL element of the present invention. First, a substrate 2, a first electrode layer 3 formed on the substrate 2, an insulating layer 4 formed on the first electrode layer 3, and a plurality of second electrode layers formed on the insulating layer 4 An organic EL element substrate 1 having a plurality of insulating partition walls 5 defining a dividing region 10 to be divided is prepared (FIG. 6A, organic EL element substrate preparing step). In this organic EL element substrate 1, each of the partition walls 5 is composed of a plurality of small partition walls 5a and 5b provided in parallel at a predetermined interval d, and the height h of each of the small partition walls 5a and 5b is It forms so that it may exist in the range of 0.5 micrometer-2 micrometers. In the example shown in FIG. 6A, as illustrated in FIG. 2, the barrier ribs 5 (small barrier ribs 5a, 5b) are perpendicular to the stripe pattern of the first electrode layer 3. 5 (small partition walls 5a, 5b) are formed. FIG. 6A is a cross-sectional view taken along the line AA in FIG.

  Next, an organic layer forming coating solution is applied to the entire surface of the organic EL element substrate 1 by, for example, a gravure printing method to form an organic layer 6 (FIG. 6B, organic layer forming step). In the example shown in FIG. 6B, a light emitting layer is formed as the organic layer 6. In the present invention, since the height h of the small partition walls 5a and 5b is within the above range, it becomes easy to fill the light emitting region 11 with the coating liquid for forming the organic layer, and the desired organic layer 6 is formed. Can do.

  Next, on the organic layer 6, for example, a metal material is formed by vacuum deposition to form the second electrode layer 7 (FIG. 6C, second electrode layer forming step). Since the metal material is also deposited between the small partitions 5a and 5b, the second electrode layer 7 is also formed between the small partitions 5a and 5b. The second electrode layer 7 is divided by the partition walls 5 (small partition walls 5a and 5b).

  According to the present invention, since the organic layer is formed on the above-described organic EL element substrate by a printing method, the height of the small partition wall is low, so that the organic layer is formed in the light emitting region provided between the adjacent partition walls. A desired organic layer can be formed by sufficiently filling the coating liquid. In addition, since there are a plurality of small barrier ribs, when the second electrode layer is further formed on the organic EL layer, the second electrode layer is surely divided and short-circuited between the second electrode layers located across the barrier ribs. It is possible to prevent.

Although the manufacturing method of the organic EL element of this invention should just have the said organic EL element board | substrate preparation process and the said organic layer formation process, it has an organic layer formation process and forms organic EL layer After the layer forming step or the organic EL layer forming step, a second electrode layer forming step for forming the second electrode layer on the organic EL layer can be included.
Hereinafter, each process in the manufacturing method of the organic EL element of this invention is demonstrated.

1. Organic EL Element Substrate Preparation Step The organic EL element substrate preparation step in the present invention is a step of preparing the above-described organic EL element substrate. The method for preparing the organic EL element substrate has been described in detail in the section “A. Substrate for organic EL element”, and will not be described here.

2. Organic layer forming step The organic layer forming step in the present invention is a step of forming at least one organic layer of the organic layers constituting the organic EL layer including the light emitting layer on the organic EL element substrate by a printing method. is there.

  The organic EL layer used in the present invention has one or more organic layers including at least a light emitting layer. That is, the organic EL layer is a layer including at least a light emitting layer, and the layer configuration is a layer having one or more organic layers. Usually, when an organic EL layer is formed by a wet process by coating, it is often difficult to stack a large number of layers in relation to a solvent, so that it is often composed of one or two organic layers. However, it is possible to further increase the number of layers by devising organic materials or combining vacuum deposition methods.

  Examples of the organic layer constituting the organic EL layer other than the light emitting layer include a hole injection layer, an electron injection layer, a hole transport layer, and an electron transport layer. The hole transport layer may be integrated with the hole injection layer by imparting a hole transport function to the hole injection layer. In addition, the electron transport layer may be integrated with the electron injection layer by adding an electron transport function to the electron injection layer. Furthermore, as an organic layer which comprises an organic EL layer, the layer etc. for preventing the penetration of a hole or an electron like a carrier block layer, and improving recombination efficiency can be mentioned.

  In the present invention, at least one organic layer among the organic layers constituting the organic EL layer is formed by a printing method. The number of organic layers formed by the printing method may be one or more, for example, one layer, two layers, three layers, and the like.

  Examples of the organic layer formed by the printing method include a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer. Especially, it is preferable that the organic layer formed by the printing method is a light emitting layer. The organic layer formed by a printing method may be a hole injection layer and a light emitting layer.

When the organic layer is formed, an organic layer forming coating solution for forming the organic layer is applied on the organic EL element substrate by a printing method. A material corresponding to the type of the organic layer is used for the organic layer forming coating solution.
Hereinafter, the organic layer and the method for forming the organic layer in this step will be described separately.

(1) Organic layer (i) Light-emitting layer Examples of the material used for the light-emitting layer in the present invention include light-emitting materials such as dye-based materials, metal complex-based materials, and polymer-based materials.

  Examples of dye materials include cyclopentadiene derivatives, tetraphenylbutadiene derivatives, triphenylamine derivatives, oxadiazole derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, silole derivatives, thiophene ring compounds, pyridine ring compounds. Perinone derivatives, perylene derivatives, oligothiophene derivatives, trifumanylamine derivatives, oxadiazole dimers, pyrazoline dimers, and the like.

  Examples of the metal complex-based material include an aluminum quinolinol complex, a benzoquinolinol beryllium complex, a benzoxazole zinc complex, a benzothiazole zinc complex, an azomethylzinc complex, a porphyrin zinc complex, and a eurobium complex. Alternatively, a metal complex having a rare earth metal such as Tb, Eu, or Dy and having a ligand such as oxadiazole, thiadiazole, phenylpyridine, phenylbenzimidazole, or quinoline structure can be given.

  Furthermore, examples of the polymer material include polyparaphenylene vinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyvinylcarbazole, polyfluorene derivatives, polyquinoxaline derivatives, and copolymers thereof. be able to.

  A dopant may be added to the light emitting layer for the purpose of improving the light emission efficiency and changing the light emission wavelength. Examples of such doping agents include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squalium derivatives, porphyrin derivatives, styryl dyes, tetracene derivatives, pyrazoline derivatives, decacyclene, phenoxazone, quinoxaline derivatives, carbazole derivatives, fluorene derivatives. Etc.

  The thickness of the light emitting layer is not particularly limited as long as it can provide a function of emitting light by providing a recombination field between electrons and holes, and is, for example, about 1 nm to 500 nm. can do.

  In the present invention, the light emitting layer is divided by the partition walls and formed into a pattern. At this time, the light emitting layer is preferably formed in a pattern so as to have light emitting portions of a plurality of colors such as red, green, and blue. Thereby, it can be set as the organic EL element in which a color display is possible. In this case, for example, the organic EL element substrate 1 shown in FIG. 2 is used to have a red light emitting portion 8R, a green light emitting portion 8G, and a blue light emitting portion 8B as illustrated in FIGS. A light emitting layer can be formed in a pattern.

(Ii) Hole Injection Layer As described above, the hole transport layer may be integrated with the hole injection layer by imparting a hole transport function to the hole injection layer. That is, the hole injection layer may have only a hole injection function, or may have both a hole injection function and a hole transport function.

  The material used for the hole injection layer is not particularly limited as long as it can stabilize the injection of holes into the light emitting layer, and the compounds exemplified as the light emitting material for the light emitting layer. In addition, phenylamine-based, starburst-type amine-based, phthalocyanine-based, polyaniline, polythiophene, polyphenylene vinylene derivatives, and the like can be used. Specifically, bis (N- (1-naphthyl) -N-phenyl) benzidine (α-NPD), 4,4,4-tris (3-methylphenylphenylamino) triphenylamine (MTDATA), poly-3 4,4 ethylenedioxythiophene-polystyrene sulfonic acid (PEDOT-PSS), polyvinylcarbazole (PVCz), and the like.

  Further, the thickness of the hole injection layer is not particularly limited as long as the hole injection function and the hole transport function are sufficiently exerted, but specifically, within the range of 0.5 nm to 1000 nm, Especially, it is preferable that it exists in the range of 10 nm-500 nm.

(Iii) Electron Injection Layer As described above, the electron transport layer may be integrated with the electron injection layer by adding an electron transport function to the electron injection layer. That is, the electron injection layer may have only an electron injection function, or may have both an electron injection function and an electron transport function.

The material used for the electron injecting layer is not particularly limited as long as it can stabilize the injection of electrons into the light emitting layer, and compounds exemplified as the light emitting material of the light emitting layer can be used. Can be used.
Alternatively, a metal doped layer in which an alkali metal or alkaline earth metal is doped on an electron transporting organic material may be formed and used as an electron injection layer. Examples of the electron-transporting organic material include bathocuproine, bathophenanthroline, and phenanthroline derivatives. Examples of the metal to be doped include Li, Cs, Ba, and Sr.

  The thickness of the electron injection layer is not particularly limited as long as the electron injection function and the electron transport function are sufficiently exhibited.

(Iv) Electron transport layer The material used for the electron transport layer is not particularly limited as long as it is a material capable of transporting electrons injected from the cathode into the light emitting layer. For example, bathocuproine, Examples include bathophenanthroline, phenanthroline derivatives, triazole derivatives, oxadiazole derivatives, and derivatives of tris (8-quinolinolato) aluminum complex (Alq ₃ ).

  The thickness of the electron transport layer is not particularly limited as long as the electron transport function is sufficiently thick.

(2) Formation method of organic layer The coating liquid for organic layer formation used for this process is prepared by dissolving or dispersing the material which comprises the said organic layer in a solvent. The solvent is appropriately selected according to the material constituting the organic layer. For example, when the light emitting layer is formed as the organic layer, the solvent used in the light emitting layer forming coating solution is not particularly limited as long as it can dissolve or disperse the light emitting material described above. , Chloroform, methylene chloride, dichloroethane, tetrahydrofuran, toluene, xylene, tetralin, mesitylene and the like.

In this step, as described above, the organic layer forming coating solution is applied onto the organic EL element substrate by a printing method. This is because the organic layer forming coating solution can be easily filled in the light emitting region and the organic layer forming coating solution can be prevented from entering between the small partition walls.
Specific examples of the printing method include a gravure printing method and a letterpress printing method. As the printing plate and blanket, for example, metal, rubber, plastic, or the like can be used. Among them, the plate is preferably made of metal, and the blanket is preferably a resin film wound around a blanket cylinder having a cushion layer on the surface. The hardness of the cushion layer is, for example, in the range of 20 ° to 80 °, and the thickness of the cushion layer is, for example, in the range of 0.1 mm to 30 mm. In addition, said hardness is TypeA hardness by a JIS (K6253) durometer hardness test. The thickness of the resin film is, for example, in the range of 5 μm to 200 μm. For example, the gravure plate cell has a maximum opening length in the range of 20 μm to 200 μm and a depth in the range of 10 μm to 200 μm. Further, the drum diameter of the printing press is proportional to the size of the printing medium, and is appropriately selected according to the size of the printing medium. For example, the drum diameter is within a range of 10 mm to 1000 mm. .

  In applying the organic layer forming coating solution, as illustrated in FIG. 6B, the organic layer forming coating solution may be applied to the entire surface of the organic EL element substrate 1, as shown in FIG. ), An organic layer forming coating solution may be applied in a pattern on the organic EL element substrate 1. 9A to 9C are process diagrams showing another example of the method for manufacturing the organic EL element of the present invention.

  In addition, when the organic layer forming coating solution is applied, as illustrated in FIG. 2, when the small partition walls (5a, 5b) constituting the partition wall 5 are formed in a straight line, the organic layer forming coating solution is used. May be applied perpendicularly to the longitudinal direction of the small partition walls, or may be applied parallel to the longitudinal direction of the small partition walls. For example, when the light emitting layer is formed in a pattern so as to have three color light emitting parts of a red light emitting part 8R, a green light emitting part 8G, and a blue light emitting part 8B, the organic EL element substrate 1 illustrated in FIG. As shown in FIG. 7, each light emitting layer forming coating solution may be applied perpendicularly to the longitudinal direction of the small barrier ribs 5 a and 5 b, and as shown in FIG. You may apply | coat each coating liquid for light emitting layer formation in parallel with respect to the longitudinal direction of 5a and 5b.

  You may dry after application | coating of the coating liquid for organic layer formation.

In the present invention, the height of the organic layer at the end of the small partition provided on the light emitting region side among the plurality of small partitions constituting the partition is t ₁ , and the small provided on the light emitting region side. when the light emitting region side of the partition wall in which the height of the organic layer at the end opposite the t _2, it is preferable that t _1> t _2.

  Since the definition of the light emitting region is described in the above section “A. Organic EL element substrate”, the description thereof is omitted here.

  The “small partition provided on the light emitting region side among the plurality of small partitions constituting the partition” refers to two small partitions located at both ends of the partition among the plurality of small partitions constituting the partition. As illustrated in FIG. 2, when the partition wall 5 is composed of two small partition walls 5 a and 5 b, both of the two small partition walls 5 a and 5 b are small partition walls positioned at both ends of the partition wall 5. On the other hand, as illustrated in FIG. 10, when the partition wall 5 includes three small partition walls 5 a, 5 b, and 5 c, the three partition walls 5 a, 5 b, and 5 c are positioned at both ends of the partition wall 5. The two small partitions are the small partitions 5a and 5c.

Further, “the height t ₁ of the organic layer at the end of the small partition provided on the light emitting region side on the light emitting region side” is the end of the small partition provided on the light emitting region side on the light emitting region side. The height from the surface of the base layer of the small partition wall to the surface of the organic layer. As illustrated in FIG. 6B, when the small partition walls 5a and 5b are formed immediately above the insulating layer 4, the base layer of the small partition walls 5a and 5b is the insulating layer 4, and the organic layer the height t ₁ is a height from the insulating layer 4 surface at the end portion of the light emitting region 11 side of the small partition wall 5a to the organic layer 6 surface. Further, as illustrated in FIG. 11B, when the small partition walls 5 a and 5 b are formed immediately above the first electrode layer 3, the base layer of the small partition walls 5 a and 5 b is the first electrode layer 3. The height t ₁ of the organic layer is the height from the surface of the first electrode layer 3 to the surface of the organic layer 6 at the end of the small partition wall 5a on the light emitting region 11 side. That is, the height t ₁ of the organic layer refers to the height (thickness) of only the organic layer at the end of the small partition wall on the light emitting region side.
11A to 11C are process diagrams showing another example of the method for manufacturing the organic EL element of the present invention.

On the other hand, “the height t ₂ of the organic layer at the end opposite to the light emitting region side of the small partition provided on the light emitting region side” is the light emitting region side of the small partition provided on the light emitting region side. Means the height from the surface of the base layer of the small partition wall to the surface of the organic layer at the opposite end. As illustrated in FIG. 6B, when the small partition walls 5a and 5b are formed immediately above the insulating layer 4, the base layer of the small partition walls 5a and 5b is the insulating layer 4, and the organic layer the height t ₂ is a height from the insulating layer 4 surface at an end portion opposite to the light-emitting region 11 side of the small partition wall 5a to the organic layer 6 surface. Further, as illustrated in FIG. 11B, when the small partition walls 5 a and 5 b are formed immediately above the first electrode layer 3, the base layer of the small partition walls 5 a and 5 b is the first electrode layer 3. There, the height t ₂ of the organic layer is a height from the first electrode layer 3 surface in the end portion opposite to the light-emitting region 11 side of the small partition wall 5a to the organic layer 6 surface. That is, the height t ₂ of the organic layer, it refers to an organic layer only in height at the opposite end (thickness) to the light emitting region side of the small septum.

Here, the end portion of the small partition wall means the outermost end portion of the small partition wall. For example, when the cross-sectional shape of the small partition is an inversely tapered shape, the end of the small partition becomes the end of the upper bottom surface as illustrated in FIG. For example, when the cross-sectional shape of the small partition is a forward tapered shape, the end of the small partition is an end of the lower bottom surface as illustrated in FIG.
That is, for example, when the cross-sectional shape of the small partition is an inversely tapered shape, the height t ₁ of the organic layer at the end of the small partition provided on the light emitting region side on the light emitting region side is shown in FIG. As illustrated in FIG. 11B, the organic layer has a height t ₁ at the end of the upper bottom surface of the small partition wall 5 a on the light emitting region 11 side. Further, the height t ₂ of the organic layer at the end opposite to the light emitting region side of the small partition provided on the light emitting region side is, as illustrated in FIGS. 6B and 11B, It becomes the height t ₂ of the organic layer at the end portion of the bottom surface on the side opposite to the light-emitting region 11 side of the small septum 5a.
For example, when the cross-sectional shape of the small partition is a forward tapered shape, the height t ₁ of the organic layer at the end of the small partition provided on the light emitting region side on the light emitting region side is as illustrated in FIG. , the height t ₁ of the organic layer at the end portion of the bottom surface of the light emitting region 11 side of the small septum 5a. The height t ₂ of the organic layer at the end opposite to the light emitting region side of the small partition wall provided in the light emitting region side, as illustrated in FIG. 12, a light emitting region 11 side of the small partition wall 5a is the height t ₂ of the organic layer at the end portion of the bottom surface of the opposite side.

The height t ₁ and t ₂ of the organic layer can be measured with a scanning white interferometer manufactured by Zygo or a laser microscope manufactured by Keyence.

As t ₂ , the height from the substrate surface to the organic layer surface is higher than the height from the substrate surface to the surface of the small partition wall at the end of the small partition wall provided on the light emitting region side opposite to the light emission region side. low and may be lower than _{t 1.} In the example shown in FIG. 6 (b) and FIG. 9 _(b), although the case of _t 2 = 0 are _shown, if t 1> _{t 2,} as illustrated in FIG. 13 _{t 2} It may be> 0.
Specifically, t ₂ is preferably 0.5 or less, more preferably 0.2 or less, and further preferably 0.1 or less, where the thickness of the small partition wall is 1. This is because, if the ratio is within the above range, the second electrode layer can be reliably divided and a short circuit between the second electrode layers positioned with the partition wall interposed therebetween can be effectively suppressed.
More specifically, t ₂ is preferably in the range of 0 nm to 500 nm, more preferably in the range of 0 nm to 250 nm, and still more preferably in the range of 0 nm to 100 nm. If t ₂ is in the above range, as in the case described above, the second electrode layer reliably separated, it because it is possible to effectively suppress a short circuit in the second electrode layers located across a partition wall It is.

t ₁ is not particularly limited as long as it is higher than t ₂ .

3. Organic EL layer formation process The organic EL layer formation process in this invention has the said organic layer formation process, and is a process of forming an organic EL layer.

  The organic EL layer has one or a plurality of organic layers including at least a light emitting layer, and the layer structure is as described in the section of the organic layer forming step. In the present invention, at least one of the organic layers constituting the organic EL layer may be formed by a printing method, and other layers constituting the organic EL layer may be formed by a method other than the printing method. it can. For example, after a hole injection layer and a light emitting layer are sequentially formed on a substrate for an organic EL element by a printing method, an electron transport layer and an electron injection layer are formed on the light emitting layer by a method other than the printing method, for example, a vacuum deposition method. Can be formed. Further, for example, after the hole injection layer is formed on the organic EL element substrate by a method other than the printing method, for example, the spin coating method, the light emitting layer can be formed on the hole injection layer by the printing method.

  As described above, at least one organic layer constituting the organic EL layer may be formed by a printing method, and other layers constituting the organic EL layer may be formed by a method other than the printing method. Of the organic layers constituting the layer, it is preferable to form all of the organic layers formed by a wet method by a printing method. This is because the effect of the present invention can be particularly exhibited.

  Hereinafter, the description will be made by dividing into other layers formed by a method other than the printing method and methods other than the printing method.

(1) Other layer formed by a method other than the printing method In the present invention, the other layer formed by a method other than the printing method is preferably a layer other than the light emitting layer. Examples of such a layer include a hole injection layer, an electron injection layer, and an electron transport layer. Hereinafter, these layers will be described.

(I) Hole injection layer The hole transport layer may be integrated with the hole injection layer by imparting a hole transport function to the hole injection layer. That is, the hole injection layer may have only a hole injection function, or may have both a hole injection function and a hole transport function.

  The material used for the hole injection layer is not particularly limited as long as it can stabilize the injection of holes into the light emitting layer, and the compounds exemplified as the light emitting material for the light emitting layer. In addition, phenylamine, starburst amine, phthalocyanine, vanadium oxide, molybdenum oxide, ruthenium oxide, aluminum oxide, titanium oxide and other oxides, amorphous carbon, polyaniline, polythiophene, polyphenylene vinylene derivatives, etc. may be used. it can. Specifically, bis (N- (1-naphthyl) -N-phenyl) benzidine (α-NPD), 4,4,4-tris (3-methylphenylphenylamino) triphenylamine (MTDATA), poly-3 4,4 ethylenedioxythiophene-polystyrene sulfonic acid (PEDOT-PSS), polyvinylcarbazole (PVCz), and the like.

  Further, the thickness of the hole injection layer is not particularly limited as long as the hole injection function and the hole transport function are sufficiently exerted, but specifically, within the range of 0.5 nm to 1000 nm, Especially, it is preferable that it exists in the range of 10 nm-500 nm.

(Ii) Electron injection layer The electron transport layer may be integrated with the electron injection layer by imparting an electron transport function to the electron injection layer. That is, the electron injection layer may have only an electron injection function, or may have both an electron injection function and an electron transport function.

  The material used for the electron injection layer is not particularly limited as long as it can stabilize the injection of electrons into the light emitting layer. In addition to the compounds exemplified as the light emitting material for the light emitting layer, Aluminum lithium alloy, lithium fluoride, strontium, magnesium oxide, magnesium fluoride, strontium fluoride, calcium fluoride, barium fluoride, aluminum oxide, strontium oxide, calcium, polymethyl methacrylate, sodium polystyrene sulfonate, lithium, cesium Alkali metals such as cesium fluoride, alkali metal halides, alkali metal organic complexes, and the like can be used.

  Alternatively, a metal doped layer in which an alkali metal or alkaline earth metal is doped on an electron transporting organic material may be formed and used as an electron injection layer. Examples of the electron-transporting organic material include bathocuproine, bathophenanthroline, and phenanthroline derivatives. Examples of the metal to be doped include Li, Cs, Ba, and Sr.

  The thickness of the electron injection layer is not particularly limited as long as the electron injection function and the electron transport function are sufficiently exhibited.

(Iii) Electron transport layer The material used for the electron transport layer is not particularly limited as long as it is a material capable of transporting electrons injected from the cathode into the light emitting layer. For example, bathocuproine, batho Phenanthroline, a phenanthroline derivative, a triazole derivative, an oxadiazole derivative, or a tris (8-quinolinolato) aluminum complex (Alq ₃ ) can be given.

  The thickness of the electron transport layer is not particularly limited as long as the electron transport function is sufficiently thick.

(2) Method other than printing method The method other than the printing method may be a wet method or a dry method.

  Examples of the wet method include a method of applying a coating liquid. Examples of the coating method include a dip coating method, a roll coating method, a blade coating method, a spin coating method, a bar coating method, a wire bar coating method, a casting method, and an LB method. Further, a discharge method such as an ink jet method, a transfer method such as a thermal transfer method, and the like can be given.

  As the dry method, a general vapor deposition method such as a vacuum vapor deposition method can be used.

4). Second electrode layer forming step The second electrode layer forming step in the present invention is a step of forming the second electrode layer on the organic EL layer.

  The second electrode layer may be an anode or a cathode, but is usually formed as a cathode.

  The second electrode layer may or may not have transparency, and is appropriately selected depending on the light extraction surface and the like. For example, when light is extracted from the second electrode layer side, the second electrode layer needs to be transparent or translucent.

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

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

  In this step, it is preferable to form a second electrode layer by forming a metal material on the organic EL layer. This is because the second electrode layer may be made of a material having a low resistance, and a metal material is most suitable.

  As a method for forming a metal material, a general electrode forming method can be used. For example, a general vapor deposition method such as a vacuum vapor deposition method, a sputtering method, an ion plating method, or a method for applying a metal paste. Etc. Among these, a vacuum deposition method and a method of applying a metal paste are preferable. The vacuum evaporation method is a method that causes little damage to the organic EL layer in a dry process and is suitable for stacking. Further, the method of applying the metal paste is a wet process, and the wet process is more suitable for dealing with a larger area than the dry process. Even in the wet process, a metal paste containing a solvent that does not affect the organic EL layer can be used. That is, a wet process can be applied by devising the organic EL layer so as not to be affected by the solvent resistance of the organic EL layer.

  In addition, when the insulating layer is not formed between the 1st electrode layer and the partition, the board | substrate 1 for organic EL elements which is illustrated to FIG. 5 and FIG. 11 (a) is used. When the organic layer 6 and the second electrode layer 7 are formed using such an organic EL element substrate 1 as illustrated in FIGS. 11B and 11C, as illustrated in FIG. 11C. The first electrode layer 3 and the second electrode layer 7 may be in contact with each other between the small partition walls 5a and 5b. In the present invention, the second electrode layer 7 located between the small barrier ribs 5a and 5b is separated from the second electrode layer 7 located in the light emitting region 11, and does not participate in voltage application. Therefore, even when the insulating layer is not formed and the first electrode layer and the second electrode layer are in contact with each other between the small partition walls, there is no short circuit between the first electrode layer and the second electrode layer. .

C. Organic EL Element Next, the organic EL element of the present invention will be described. The organic EL element of the present invention is formed on the organic EL element substrate described above and the first electrode layer between the partition walls of the organic EL element substrate, and includes an organic EL layer including a light emitting layer, and the organic EL layer. And the second electrode layers adjacent to each other with the partition wall interposed therebetween are electrically insulated from each other.

The organic EL element of the present invention will be described with reference to the drawings. FIG. 14 is a schematic cross-sectional view showing an example of the organic EL element of the present invention. In the organic EL element 20 illustrated in FIG. 14, the first electrode layer 3 is formed on the substrate 2, the insulating layer 4 is formed on the first electrode layer 3, and the second electrode layer is formed on the insulating layer 4. The organic EL element substrate having a plurality of insulating partition walls 5 defining a dividing region 10 for dividing the substrate into a plurality of regions, and further, a light emission formed on the first electrode layer 3 between the partition walls 5. It has a layer 8 and a second electrode layer 7 formed on the light emitting layer 8 and divided by the partition wall 5.
Each of the partition walls 5 is composed of a plurality of small partition walls 5a and 5b provided in parallel at a predetermined interval d. Further, the height h of the small partition walls 5a and 5b is in the range of 0.5 μm to 2 μm. In the example shown in FIG. 14, as illustrated in FIG. 2, the barrier ribs 5 (small barrier ribs 5 a) are arranged so that the stripe pattern of the barrier ribs 5 (small barrier ribs 5 a, 5 b) is orthogonal to the stripe pattern of the first electrode layer 3. 5b) is formed.
Further, the second electrode layers 7 adjacent to each other with the partition wall 5 interposed therebetween are electrically insulated from each other.

  When manufacturing such an organic EL element, as shown in FIG. 6B, when an organic layer such as a light emitting layer is formed, the height h between the small partition walls 5a and 5b is within the above range. Therefore, it becomes easy to fill the light emitting region 11 with the organic layer forming coating solution, and the desired organic layer 6 can be formed.

  According to the present invention, since the organic EL element substrate described above is used, a desired organic layer is formed by sufficiently filling a light emitting region provided between adjacent partition walls with an organic layer forming coating solution. be able to. In addition, the second electrode layer is surely divided by preventing the organic layer forming coating liquid from entering a large amount between the small partition walls, thereby preventing a short circuit between the second electrode layers located across the partition walls. Is possible.

  The substrate, the first electrode layer, the partition wall, the dividing region, and the insulating layer have been described in detail in the above section “A. Substrate for organic EL element”, and thus description thereof is omitted here. Hereinafter, the other structure in the organic EL element of this invention is demonstrated.

1. 2nd electrode layer The 2nd electrode layer in this invention is formed on the said organic EL layer, and is parted by the said partition.

In the present invention, the height of the second electrode layer at the end of the small partition provided on the light emitting region side among the plurality of small partitions constituting the partition is t ₃ , and is provided on the light emitting region side. It is preferable that t ₃ > t ₄ when the height of the second electrode layer at the end of the small partition opposite to the light emitting region is t ₄ .

  Of the plurality of small partitions constituting the light emitting region, the small partition provided on the light emitting region side, the end of the small partition provided on the light emitting region side on the light emitting region side, and the light emitting region side. The definition of the end of the small partition opposite to the light emitting region side is described in the above-mentioned sections “A. Substrate for organic EL element” and “B. Method for manufacturing organic EL element”. Description of is omitted.

“Height t ₃ of the second electrode layer at the end of the small partition provided on the light emitting region side on the light emitting region side” is the end of the small partition provided on the light emitting region side on the light emitting region side. This refers to the height from the surface of the base layer of the small partition wall to the surface of the second electrode layer. As illustrated in FIGS. 14 to 16, when the small partitions 5 a and 5 b are formed immediately above the insulating layer 4, the base layer of the small partitions 5 a and 5 b is the insulating layer 4, and the second electrode height t ₃ of the layer is a height from the insulating layer 4 surface at the end portion of the light emitting region 11 side of the small partition wall 5a to the second electrode layer 7 surface. In addition, as illustrated in FIG. 17, when the small partition walls 5 a and 5 b are formed immediately above the first electrode layer 3, the base layer of the small partition walls 5 a and 5 b is the first electrode layer 3. height t ₃ of the second electrode layer is a height from the first electrode layer 3 surface in the end portion of the light emitting region 11 side of the small partition wall 5a to the second electrode layer 7 surface.

On the other hand, “the height t ₄ of the second electrode layer at the end opposite to the light emitting region side of the small partition provided on the light emitting region side” is the light emitting region of the small partition provided on the light emitting region side. The height from the surface of the base layer of the small partition wall to the surface of the second electrode layer at the end opposite to the side. As illustrated in FIGS. 14 to 16, when the small partitions 5 a and 5 b are formed immediately above the insulating layer 4, the base layer of the small partitions 5 a and 5 b is the insulating layer 4, and the second electrode the height t ₄ of the layers, the height of the insulating layer 4 surface at an end portion opposite to the light-emitting region 11 side of the small partition wall 5a to the second electrode layer 7 surface. In addition, as illustrated in FIG. 17, when the small partition walls 5 a and 5 b are formed immediately above the first electrode layer 3, the base layer of the small partition walls 5 a and 5 b is the first electrode layer 3. the height t ₄ of the second electrode layer is a height from the first electrode layer 3 surface in the end portion opposite to the light-emitting region 11 side of the small partition wall 5a to the second electrode layer 7 surface.

The method for measuring the heights t ₃ and t ₄ of the second electrode layer is the same as the method for measuring the heights t ₁ and t ₂ of the organic layer in “B. Manufacturing method of organic EL element”. Therefore, explanation here is omitted.

The t _4, at the end opposite to the light emitting region side of the small partition wall provided in the light emitting region side, the height from the substrate surface to the second electrode layer surface is high from the substrate surface to the small surface of the partition wall lower than of, and may be lower than t _3. Specifically, t ₄ is preferably 0.5 or less, more preferably 0.4 or less, and further preferably 0.3 or less, where the thickness of the small partition wall is 1. This is because, if the ratio is within the above range, the second electrode layer can be reliably divided and a short circuit between the second electrode layers positioned with the partition wall interposed therebetween can be effectively suppressed.
More specifically, t ₄ is preferably in the range of 50 nm to 1000 nm, more preferably in the range of 50 nm to 800 nm, and still more preferably in the range of 50 nm to 600 nm. If t ₄ is in the above range, as in the case described above, the second electrode layer reliably separated, it because it is possible to effectively suppress a short circuit in the second electrode layers located across a partition wall It is.

t ₃ is not particularly limited as long as it is higher than t ₄ .

  Further, the second electrode layers adjacent to each other with the partition wall interposed therebetween are electrically insulated from each other. In addition, it can confirm that the 2nd electrode layer adjacent on both sides of a partition is mutually insulated by the presence or absence of the conduction | electrical_connection by a tester, the presence or absence of the light emission by voltage application, etc.

  Since the other points of the second electrode layer are described in the section of the second electrode layer forming step in “B. Manufacturing method of organic EL element”, description thereof is omitted here.

2. Organic EL Layer The organic EL layer used in the present invention has one or more organic layers including at least a light emitting layer.
The layer configuration of the organic EL layer and each layer constituting the organic EL layer are described in detail in the section of the organic layer forming step and the organic EL layer forming step in “B. Manufacturing method of organic EL element” above. The description in is omitted.

  At least one organic layer of the organic layers constituting the organic EL layer may have a meniscus cross-sectional shape. For example, in FIGS. 14-16, the light emitting layer 8 located between the adjacent partition walls 5 has a meniscus cross-sectional shape. When the organic layer such as the light emitting layer constituting the organic EL layer has a meniscus cross-sectional shape, the second electrode layer formed on the organic EL layer may be connected to the light emitting region and the divided region. However, in the present invention, the partition wall is composed of a plurality of small partition walls, and the height of the small partition walls is within a predetermined range, so that the second electrode layer can be reliably divided. Therefore, in the case where at least one of the organic layers constituting the organic EL layer has a meniscus cross-sectional shape, the second electrode layer located between the partition walls is formed by the configuration of the present invention. Can be effectively suppressed.

  In addition, it can confirm with the electron micrograph of the cross section of an organic EL element that the organic layer which comprises an organic EL layer has a meniscus cross-sectional shape.

The number of organic layers having a meniscus cross-sectional shape may be one or more, for example, one layer, two layers, three layers, and the like.
The organic layer having a meniscus cross-sectional shape is preferably a light emitting layer. This organic layer may be a hole injection layer and a light emitting layer.

  As a formation position of the organic EL layer, each layer constituting the organic EL layer may be formed at least in the light emitting region. For example, as shown in FIGS. 14 to 17, the light emitting layer 8 may be formed on the partition wall 5, but not necessarily formed on the partition wall although not shown. Further, when the light emitting layer is formed on the partition wall, the light emitting layer 8 may be formed on the entire partition wall 5 as illustrated in FIG. 14, FIG. 15 and FIG. As illustrated, the light emitting layer 8 may be formed on a part of the partition wall 5.

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

  Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.

[Example 1]
(Formation of transparent electrode layer)
First, an indium tin oxide (ITO) electrode film having a thickness of 200 nm is formed on a glass substrate (thickness 0.7 mm) by an ion plating method, a photosensitive resist is applied on the ITO electrode film, and mask exposure is performed. Then, development and etching of the ITO electrode film were performed to form 445 striped transparent electrode layers with a width of 125 μm at a pitch of 155 μm.

(Formation of insulating layer)
Next, the glass substrate (thickness 0.7 mm) is subjected to cleaning treatment and ultraviolet plasma cleaning, and then a positive photosensitive resist mainly composed of a polyimide precursor is applied by a spin coating method, and a photolithography process is performed. Then, an insulating layer (thickness: 1.5 μm) was formed so that light emitting regions (openings) of 100 μm × 100 μm exist at a pitch of 155 μm on each transparent electrode layer.

(Formation of partition walls)
Next, the glass substrate on which the insulating layer is formed is subjected to cleaning treatment and ultraviolet plasma cleaning, and then a negative photosensitive resist composed of a novolac resin, a phenol resin, and a melamine resin is applied by a spin coat method. Patterning was performed by a lithography process, and barrier ribs having a stripe shape and a reverse taper shape were formed in parallel on the insulating layer so as to be orthogonal to the transparent electrode layer. At this time, the number of small partition walls constituting the partition walls was set to two (2 lines). Further, the partition walls were formed with an interval between the small partition walls of 15 μm. The small partition wall had a width of 20 μm, a height of 2 μm, and an inverse taper angle of 50 °.

(Preparation of ink for hole injection layer and ink for red light emitting layer)
Next, an ink A1 for a hole injection layer having the following composition was prepared. The viscosity of the ink A1 at a shear rate of 100 / sec (ink temperature: 23 ° C.) was measured in a steady flow measurement mode using a viscoelasticity measuring apparatus MCR301 manufactured by Physica, and found to be 15 cP. The dynamic surface tension (ink temperature 23 ° C.) at 2 Hz was measured using SITA t60 / 2 (manufactured by SITA Messtechnik GmbH), and as a result, it was 30 dyne / cm.
<Composition of ink A1 for hole injection layer>
PEDOT (poly (3,4) ethylenedioxythiophene) / PSS (polystyrene sulfonate) (mixing ratio = 1/20) (Baytron PCH8000 manufactured by Bayer)
70% by weight
Mixed solvent (water: isopropyl alcohol (boiling point 82.4 ° C.) = 70:30)
... 30% by weight

Subsequently, ink B1 for red light emitting layers having the following composition was prepared. As a result of measuring the viscosity (ink temperature 23 ° C.) of the ink B1 at a shear rate of 100 / sec in the same manner as the ink A1, it was 80 cP. The surface tension of mesitylene and tetralin used as solvents was measured at a liquid temperature of 20 ° C. using a surface tension meter CBVP-Z type manufactured by Kyowa Interface Science Co., Ltd.
<Composition of ink B1 for red light emitting layer>
・ Polyfluorene derivative-based red light emitting material (molecular weight: 300,000): 2.5% by weight
-Solvent (mixed solvent of mesitylene: tetralin = 50: 50) ... 97.5% by weight
(Surface tension of mixed solvent = 32 dyne / cm, boiling point = 186 ° C.)
(Surface tension of mesitylene = 28 dyne / cm, boiling point = 165 ° C.)
(Surface tension of tetralin = 35.5 dyne / cm, boiling point = 207 ° C)

(Formation of hole injection layer and light emitting layer)
As a gravure plate, a plate-like gravure plate (effective width 80 mm) provided with square cells (one side of the cell is 100 μm and the cell depth is 35 μm) arranged in a lattice shape so that the cell spacing is 25 μm was prepared. In this gravure version, the diagonal direction of the square cell was made to coincide with the operation direction of the blanket described later.
Next, an easily-adhesive polyethylene terephthalate (PET) film (U10 manufactured by Toray Industries, Inc., thickness 100 μm, surface tension 60 dyne / cm) was prepared as a resin film. In addition, the surface tension of this film is a contact angle θ using an automatic contact angle meter (DropMaster 700 type manufactured by Kyowa Interface Science Co., Ltd.) using a liquid (standard material) of which two or more types of surface tensions are known. Was measured based on the equation: γs (surface tension of resin film) = γL (surface tension of liquid) cos θ + γSL (surface tension of resin film and liquid).
Next, a blanket was prepared by mounting the above resin film on the peripheral surface of a blanket cylinder (having a cushion layer (hardness 70 °) on the surface) having a diameter of 12 cm and a cylinder width of 30 cm. In addition, the hardness of a cushion layer is Type A hardness by a JIS (K6253) durometer hardness test.

  Next, the gravure plate and the blanket are mounted on a flat table offset printing machine, and the ink A1 for the hole injection layer is supplied to the gravure plate, and unnecessary ink is removed using a blade, and the ink is put into the cell. Filled with ink. Next, ink was received from the gravure plate into the blanket, and then the hole injection layer (thickness: about 70 nm) was formed by transferring the ink from the blanket onto the glass substrate on which the partition walls and the like were formed. The printing speed was 1000 mm / second, and drying was performed for 1 hour on a hot plate set at 120 ° C. The hole injection layer was 75 mm × 75 mm, and was formed so as to cover the opening of the insulating layer.

  Subsequently, the ink B1 for the red light emitting layer was supplied to the gravure plate, and a red light emitting layer (thickness of about 70 nm) was formed by the same operation as the formation of the hole injection layer. The printing speed was 1000 mm / second, and drying was performed for 1 hour on a hot plate set at 180 ° C. This red light emitting layer was 75 mm × 75 mm, and was formed so as to cover the hole injection layer.

(Formation of electron injection layer)
On the surface side on which the red light emitting layer was formed, a metal mask having an opening of 80 mm × 80 mm was arranged so as to be positioned on the light emitting region (opening) of the insulating layer. Next, calcium was vapor-deposited through this mask by a vacuum vapor deposition method (deposition rate = 0.1 nm / second) to form an electron injection layer (thickness 10 nm).

(Formation of second electrode layer)
Next, the metal mask used for forming the electron injection layer was used as it was, and aluminum was deposited by vapor deposition (deposition rate = 0.4 nm / second). Thereby, a second electrode layer (thickness: 300 nm) made of aluminum and having an opening of 80 mm × 80 mm was formed on the electron injection layer.
Finally, an organic EL element was obtained by bonding a sealing plate to the surface side on which the second electrode layer was formed via an ultraviolet curable adhesive.

[Comparative Example 1]
An organic EL device was produced in the same manner as in Example 1 except that the height of the small partition walls was changed to 4 μm.

[Comparative Example 2]
An organic EL device was produced in the same manner as in Example 1 except that the height of the small partition walls was changed to 0.2 μm.

[Example 2]
Example 1 is the same as Example 1 except that the partition walls were formed with a small partition wall height of 0.5 μm, and a hole transport layer was formed on the hole injection layer and a light emitting layer was formed on the hole transport layer as described below. Similarly, an organic EL device was produced.

(Formation of hole transport layer)
N, N′-diphenyl-N, N′-bis (3methylphenyl) -1,1′-biphenyl-4,4′-diamine (TPD) was deposited by vacuum deposition (deposition rate = 0.1 nm / second). )did. As a result, an 80 mm × 80 mm hole transport layer (thickness 80 nm) made of TPD was formed on the hole injection layer.

(Formation of light emitting layer)
Tris (8-quinolinolato) aluminum complex (Alq ₃ ) was deposited by vapor deposition (deposition rate = 0.1 nm / second). As a result, an 80 mm × 80 mm light emitting layer (thickness 80 nm) made of Alq ₃ was formed on the hole transport layer.

[Evaluation]
When Examples 1-2 and Comparative Examples 1-2 were evaluated, in Comparative Example 1, many short circuits occurred between the first electrode layer and the second electrode layer. In Example 1 and Example 2, no short circuit was observed. In Comparative Example 1, it is considered that the light emitting region (opening) was insufficiently filled with ink, so that a predetermined film thickness was not obtained and a short circuit occurred.
Further, in Comparative Example 2, the reverse tapered portion of the partition wall was filled with the organic layer, and many short circuits occurred between the adjacent second electrodes. In Example 1 and Example 2, the short circuit between adjacent 2nd electrodes was not seen.

DESCRIPTION OF SYMBOLS 1 ... Substrate for organic EL elements 2 ... Substrate 3 ... First electrode layer 4 ... Insulating layer 5 ... Partition 5a, 5b, 5c ... Small partition 6 ... Organic layer 7 ... Second electrode layer 8 ... Light emitting layer 10 ... Dividing region 11 ... Light emitting area 12 ... Blanket 13 ... Organic layer forming coating solution 20 ... Organic EL element

Claims (12)

A substrate,
A first electrode layer formed on the substrate;
A plurality of insulating partitions that are formed on the substrate on which the first electrode layer is formed and that divide the second electrode layer into a plurality of dividing regions;
Each of the partition walls is composed of a plurality of small partition walls provided in parallel at a predetermined interval,
The organic electroluminescence element substrate, wherein the small partition walls have a height in the range of 0.5 μm to 2 μm.   The substrate for an organic electroluminescence element according to claim 1, wherein the width of the light emitting region provided between the partition walls is 60 µm or more.   The organic electroluminescent element substrate according to claim 1 or 2, wherein a distance between the small partition walls is in a range of 1 µm to 60 µm.   The organic electroluminescent element substrate according to any one of claims 1 to 3, wherein an insulating layer is formed between the first electrode layer and the partition wall. A substrate preparation step for an organic electroluminescence element for preparing the substrate for an organic electroluminescence element according to any one of claims 1 to 4,
An organic layer forming step of forming at least one organic layer of the organic layers constituting the organic electroluminescent layer including the light emitting layer on the organic electroluminescent element substrate by a printing method. Manufacturing method of electroluminescent element. The height of the organic layer at the end of the small partition provided on the light emitting region side of the plurality of small partitions constituting the partition of the substrate for the organic electroluminescence element is t ₁ , and the light emission when the light emitting region side of the small partition wall provided in the region side where the height of the organic layer at the end opposite to the t _2, preceding claims, characterized in that a t _1> t ₂ 5. A method for producing an organic electroluminescent element according to 5.   7. The method according to claim 5, further comprising a second electrode layer forming step of forming a second electrode layer by forming a metal material on the organic electroluminescence layer after the organic layer forming step. The manufacturing method of the organic electroluminescent element of description.   The method for producing an organic electroluminescent element according to claim 7, wherein the film forming method of the metal material is a vacuum deposition method.   8. The method of manufacturing an organic electroluminescence element according to claim 7, wherein a metal paste is used as the metal material. A substrate for an organic electroluminescence element according to any one of claims 1 to 4,
An organic electroluminescence layer formed on the first electrode layer between the barrier ribs of the organic electroluminescence element substrate and including a light emitting layer;
A second electrode layer formed on the organic electroluminescence layer and divided by the partition;
2. The organic electroluminescence device according to claim 1, wherein the second electrode layers adjacent to each other across the partition are electrically insulated from each other. The height of the second electrode layer at the end of the small partition provided on the light emitting region side among the plurality of small partitions constituting the partition is t ₃ , provided on the light emitting region side. The t ₃ > t ₄ when the height of the second electrode layer at the end of the small partition opposite to the light emitting region is t _4. Organic electroluminescence element.   The organic electroluminescent element according to claim 10 or 11, wherein at least one organic layer of the organic layers constituting the organic electroluminescent layer has a meniscus cross-sectional shape.

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