JP2005078911A - Substrate applied with patterning and its manufacturing method, and organic electroluminescence display device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate (of organic EL or the like) which can permit variation of the hitting positions of ink to some extent when using an ink jet method, and its manufacturing method. <P>SOLUTION: A pixel electrode 102 made of ITO and a bank 103 which functions as a barrier rib to an ink 104 are formed on an insulating substrate 101, and a mask 106 is arranged so as to adhere closely to the top part of this bank 103. The ink 104 is injected from an ink jet nozzle 105 above the substrate 101. Lyophilic nature is provided on the surface 102 of this pixel electrode 102 and liquid repellency is provided on the surface of the bank 103 and the mask 106. Thereby, even if a part of the ink 104 hits on the bank 103 and the mask 106, the ink is drawn into the surface of the pixel electrode 102 having lyophilic nature and patterned uniformly on the surface of the pixel electrode 102, thereby, the variation of hitting positions can be permitted to some extent. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a substrate patterned with ink ejected using an ink jet method, a manufacturing method thereof, an organic electroluminescence display device, and a manufacturing method thereof.

  BACKGROUND ART Organic electroluminescence (hereinafter abbreviated as “EL”) display devices are expected to be promising as display devices to replace liquid crystal display devices in accordance with high image quality and low power consumption of mobile phones and portable information terminals. Yes. An organic EL element, which is a display element used in this organic EL display device, is formed by sequentially laminating a lower electrode (also referred to as a “pixel electrode”), an organic EL layer, and an upper electrode on a substrate made of glass or the like. It has a structure, and emits light when a current is passed between the upper electrode and the lower electrode. The organic EL layer may have, for example, a structure having only a light emitting layer, or may have a structure in which the light emitting layer is combined with one or both of a hole transport layer and an electron transport layer. Good.

  Conventionally, as a method for forming a light emitting layer or a hole transport layer on a substrate included in an organic EL device, a vacuum deposition method or the like is known when a low molecular material is used. When used, various methods such as a spin coating method, a dip method, a roll coating method, a doctor blade method, and various printing methods are known.

  In recent years, an organic EL layer can be efficiently formed for each organic EL element portion (hereinafter referred to as a “pixel forming portion”) that forms a pixel, and the arrangement (separation) of each organic material that should emit RGB colors is easy. An inkjet method having an advantage of the above has attracted attention (for example, see Patent Document 1). Here, when this ink jet method is used, the liquid substance containing the organic material, which is the ink ejected from the nozzles of the ink jet head, flows out from the pixel forming portion targeted for landing to the adjacent pixel forming portion. Sometimes. Such outflow occurs because a certain gap is provided between the inkjet head and the substrate in order to form droplets. That is, when ink is ejected from the nozzles of the inkjet head, the direction (angle) of ink ejection changes due to dirt or the like adhering to the tip of the nozzle, or the flight curve of ink due to the influence of air flow or the like. As a result, the position where the ink droplets land through the gap may deviate from the desired target position.

  Further, when an organic EL element is manufactured, the position of the substrate is often mechanically controlled by placing the element on a movable XY table and driving the XY table. Therefore, the outflow may occur due to a mechanical alignment error. Generally, the landing position accuracy determined by the ejection accuracy of the inkjet head and the alignment accuracy of the table is a value of about ± 15 to 30 μm. Due to the deviation of the landing position, it becomes difficult to form the organic EL layer with high accuracy at a desired position if the ink jet method is used without taking a configuration that does not cause the outflow.

  Therefore, conventionally, when an organic EL element is manufactured, a method of surrounding each pixel formation portion with a bank having water and oil repellency (hereinafter referred to as “liquid repellency”) has been proposed (for example, see Patent Document 2). . In this method, a plurality of pixel electrodes are formed by performing predetermined patterning on electrodes formed on a transparent substrate, and then a bank functioning as a partition is formed between adjacent pixel electrodes formed. In this method, an organic EL layer (for example, a charge injection / transport layer and / or a light emitting layer) is formed in a liquid phase in a region surrounded by the bank, and an upper electrode is formed thereon.

  Here, the thickness of the bank is generally about 1 to 3 μm, and usually an organic resin material such as polyimide, polymethyl methacrylate, or novolac resin is used as the bank material, but patterning is easy. In order to achieve this, photosensitivity is often imparted. Further, the surface of the bank needs to have a small surface free energy relative to the ink in order to impart liquid repellency. In order to impart liquid repellency to the bank surface in this way, for example, a method in which an organic resin, which is a bank material, contains a functional group containing fluorine or an additive containing silicon in advance, or carbon tetrafluoride after patterning is used. A method of performing a plasma treatment on the bank surface by using a fluorine-based gas is employed.

Further, the surface of the pixel electrode is imparted with hydrophilic / lipophilic property (hereinafter referred to as “lyophilic property”) which is a property contrary to the liquid repellency imparted to the bank surface. As a material for the pixel electrode, ITO (Indium Tin Oxide) that becomes a transparent electrode is often used. For example, a UV / O ₃ treatment or an oxygen plasma treatment, which is a known cleaning method for the surface of the pixel electrode, is used. As a result, organic (hydrocarbon) impurities can be removed, and as a result, the lyophilicity of the pixel electrode surface can be enhanced. In the case of an organic EL element, the above treatment can be expected to increase the ionization potential (work function) on the ITO surface and improve the hole injection efficiency.

As described above, liquid repellency is imparted to the bank surface and lyophilicity is imparted to the pixel electrode surface, so that even if a part of the ink lands on a part of the bank surface, Since the ink thus drawn is drawn into the surface of the pixel electrode having lyophilic properties and is uniformly patterned on the surface of the pixel electrode, it is possible to tolerate (compensate) to some extent the landing position deviation. According to such a method, as long as the ink does not land on the surface of the adjacent pixel electrode, the adjacent pixel formation portion is not contaminated with other types of ink, so that color mixing of ink in the pixel formation portion is suppressed. The
Japanese Patent Laid-Open No. 10-12377 Japanese Patent Laid-Open No. 11-87062 JP 2001-185352 A

  Here, in the conventional method using the bank (see, for example, Patent Document 2), when the definition of the organic EL display device is low (that is, the pitch is large), for example, the definition is about 100 ppi (pixel per inch), That is, when the RGB pitch is about 85 μm (= 25400 / (100 × 3)), in view of the performance of a recent ink jet apparatus, the ejected ink may land on a part of the bank, but adjacent pixels. Since the possibility of landing on the electrode surface (bank opening in contact with the electrode surface) is low, the deviation of the ink landing position is not a big problem in practice. However, a display requiring a high definition such as a display device for a mobile phone, a digital camera, or a portable information terminal generally requires a definition of about 150 to 200 ppi. In this case, in the conventional method, there is a possibility of landing on the adjacent pixel electrode surface (the bank opening portion in contact with the pixel electrode surface), so that it is difficult to suppress color mixing of ink in the pixel forming portion.

  In addition, such a deviation in the landing position of the ink is a problem when patterning the substrate by using the ink jet method, such as when a color filter substrate is manufactured by using the ink jet method.

  Therefore, in the present invention, even when there is a deviation in the ink landing position to the extent that it may land on the adjacent pixel electrode surface (the bank opening in contact with it), the deviation of the ink landing position is reduced. It is an object of the present invention to provide an acceptable substrate and a manufacturing method thereof, and an organic electroluminescence display device and a manufacturing method thereof.

1st invention is the manufacturing method of the board | substrate which performs a predetermined patterning with the predetermined liquid substance discharged by the inkjet method,
The vicinity of the periphery of the opening of the mask having an opening opened so as to expose a predetermined region of the substrate surrounded by the predetermined bank among the plurality of banks functioning as the partition walls formed on the substrate is the predetermined opening. The mask is disposed so as to be in close contact with the bank, and the liquid material is discharged into the opening.

According to a second invention, in the first invention,
The surface of the bank has a contact angle with water of 60 degrees or more.

According to a third invention, in the first invention,
The surface of the mask has a contact angle with water of 60 degrees or more.

According to a fourth invention, in the first invention,
The surface of the predetermined region of the substrate has a contact angle with water of 20 degrees or less.

According to a fifth invention, in the first invention,
When the width Gm in the predetermined direction of the opening is Gb, the maximum interval in the predetermined direction of the bank sandwiching the predetermined region is Gb, and the width in the predetermined direction near the top of the bank is W,
Gb ≦ Gm ≦ (Gb + 2W)
It is characterized by satisfying.

According to a sixth invention, in the first invention,
The vicinity of the top of the bank has a shape in which the maximum width of the region where the difference in height from the top of the bank is within 0.5 μm is 2 μm or more.

  7th invention is a manufacturing method of the organic electroluminescent display apparatus characterized by including the manufacturing method of the board | substrate as described in any one invention from 1st to 6th.

An eighth invention is a substrate on which a predetermined patterning is performed by a predetermined liquid substance ejected by an ink jet method,
A plurality of banks functioning as partition walls;
A predetermined region surrounded by a predetermined bank of the plurality of banks,
The liquid material discharged to the opening of the mask when the predetermined bank is disposed so that the vicinity of the periphery of the opening of the mask having the opening opened to expose the predetermined region is in close contact with the predetermined bank. It functions as a partition wall.

In a ninth aspect based on the eighth aspect,
The surface of the bank has a contact angle with water of 60 degrees or more.

In a tenth aspect based on the eighth aspect,
The surface of the mask has a contact angle with water of 60 degrees or more.

The eleventh invention is the eighth invention, wherein
The surface of the predetermined region of the substrate has a contact angle with water of 20 degrees or less.

In a twelfth aspect based on the eighth aspect,
When the width Gm in the predetermined direction of the opening is Gb, the maximum interval in the predetermined direction of the bank sandwiching the predetermined region is Gb, and the width in the predetermined direction near the top of the bank is W,
Gb ≦ Gm ≦ (Gb + 2W)
It is characterized by satisfying.

In a thirteenth aspect based on the eighth aspect,
The vicinity of the top of the bank has a shape in which the maximum width of the region where the difference in height from the top of the bank is within 0.5 μm is 2 μm or more.

  14th invention is an organic electroluminescent display apparatus characterized by including the board | substrate as described in any one invention from 8th to 13th.

  According to the first aspect of the present invention, the vicinity of the periphery of the opening of the mask having the opening opened to expose the surface of the predetermined region (for example, the pixel electrode) of the substrate surrounded by the bank is in close contact with the bank. In order to discharge the liquid material to the opening of the mask, for example, the landing position of the liquid material such as ink having a possibility of landing on the surface of the adjacent pixel electrode (the opening of the bank in contact with the adjacent pixel electrode) Even when there is a deviation, the deviation of the landing position can be allowed (compensated).

  According to the second aspect of the invention, the contact angle of the bank surface with respect to water is set to 60 degrees or more, so that liquid substances such as ink can be prevented from remaining on the surface of the bank. Therefore, it is possible to satisfactorily pattern a liquid substance such as ink along the pattern formed by the bank.

  According to the third invention, since the contact angle of the mask surface with respect to water is set to 60 degrees or more, it is possible to prevent liquid substances such as ink from remaining on the surface of the mask. Therefore, it is possible to satisfactorily pattern the liquid substance such as ink along the pattern formed by the bank under the mask.

  According to the fourth aspect of the invention, the contact angle with respect to the water on the surface of the predetermined region of the substrate is set to 20 degrees or less, so that liquid substances such as ink are easily drawn into the surface of the predetermined region (for example, pixel electrode) of the substrate. Therefore, it is possible to satisfactorily pattern a liquid substance such as ink along the pattern formed by the bank.

  According to the fifth aspect, the width Gm in the predetermined direction of the mask opening is not less than the maximum interval Gb in the predetermined direction of the bank sandwiching the predetermined region, and the width W in the predetermined direction near the top of the bank is equal to this interval Gb. It is below the value which added the value of 2 times. Therefore, since the bank opening in a predetermined area (for example, a pixel area) adjacent to the opening of the mask is not exposed, ink can be prevented from flowing out to the adjacent predetermined area. In addition, since the peripheral edge of the opening of the mask is not located on the inner side (predetermined region side) than the top of the bank, a part of the liquid material such as ink that contacts the mask or the bank is likely to be applied to a part of the predetermined region. . Therefore, in the normal case, all of the liquid substance such as ink is drawn into the predetermined area. Therefore, even when there is a deviation in the landing position of the liquid material such as ink, the deviation of the landing position can be allowed (compensated), and the liquid material such as ink can be satisfactorily patterned.

  According to the sixth invention, since the maximum width of the region where the height difference from the top of the bank is within 0.5 μm is 2 μm or more, the lower surface of the bank is in close contact with the vicinity of the top of the mask. Therefore, it is possible to suppress a liquid substance such as ink from flowing into a predetermined area such as an adjacent pixel area.

  According to the seventh invention, since it is a method for manufacturing an organic electroluminescence display device including the method for manufacturing a substrate according to any one of the first to sixth inventions, the bank in contact with the surface of the adjacent pixel electrode ( Even if there is a deviation in the landing position of a liquid substance such as ink that has the possibility of landing at the opening), the deviation of the landing position can be allowed (compensated). Therefore, even if the image is high definition, undesired ink does not land on the adjacent pixel region, so that color mixing, color misregistration, variation in light emission efficiency, and the like are suppressed.

According to the substrate or the organic EL display device or the manufacturing method thereof according to one embodiment of the present invention, the landing position of the ink that is the predetermined liquid material is obtained by combining the ink jet method and the method that uses a mask described later. Some deviation can be tolerated.
Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram showing a substrate before ink is landed and the state of the ink. More specifically, FIG. 1A is a plan view thereof, and FIG. It is sectional drawing. A substrate 101 shown in FIG. 1 is an insulating substrate made of glass, and a pixel electrode 102 made of ITO (Indium Tin Oxide) and a bank 103 functioning as a partition for the ink 104 are formed on the substrate 101. It is formed. A mask 106 is disposed so as to be in close contact with the top of the bank 103. The ink 104 is ejected from an inkjet nozzle 105 disposed above the substrate 101 by a predetermined distance.

  The substrate 101 is a substrate included in a bottom emission type organic EL display device, but may be a substrate included in a top emission type organic EL display device. The manufacturing method of the substrate 101 described below can also be applied to the production of a color filter substrate using an ink jet method, the patterning of a metal wiring, and the like.

  Here, as described above, there is a possibility that the ink 104 ejected from the inkjet nozzle 105 may deviate from the target landing position due to dirt on the nozzle tip, bending of the flight, generation of satellites, and the like. Generally, an error of about ± 15 μm is inevitable. Therefore, lyophilicity is imparted to the surface of the pixel electrode 102, and lyophobicity is imparted to the surfaces of the bank 103 and the mask 106. Then, even if a part of the ink 104 has landed on the surface of the bank 103 or the surface of the mask 106, the ink that has landed on the surface of the bank 103 or the surface of the mask 106 is drawn into the surface of the pixel electrode 102 having lyophilicity. In addition, since the patterning is uniformly performed on the surface of the pixel electrode 102, a deviation of the landing position can be allowed to some extent. Hereinafter, it will be described in detail with reference to the drawings.

  FIG. 2 is a schematic diagram showing the substrate immediately after the ink has landed and the state of the ink. More specifically, FIG. 2A is a plan view thereof, and FIG. It is sectional drawing. As shown in the figure, even if the landing position of the ink 104 ejected from the inkjet nozzle 105 deviates from a target position (for example, near the center of the pixel electrode 102), a part of the ink 104 is lyophilic. As long as it covers a part of the pixel electrode 102, the bank 103 and the mask 106 disposed in close contact with the bank 103 have liquid repellency, so that all the ink 104 is drawn onto the pixel electrode 102. To go.

  FIG. 3 is a schematic view showing a state of the substrate when all the ink is drawn on the pixel electrode. More specifically, FIG. 3A is a plan view thereof, and FIG. It is AA sectional drawing. As shown in the figure, since the ink 104 spreads uniformly on the surface of the pixel electrode 102 and is formed into a film, patterning suitable for the pattern formed by the bank 103 is performed.

  As described above, the bank 103 and the mask 106 allow the deviation of the landing position to some extent, specifically, the deviation to the extent that at least a part of the ink 104 is applied to the pixel electrode 102, but the mask 106 is not used. Sometimes the landing position shift is not allowed. Hereinafter, the case where this deviation is not allowed will be described with reference to FIGS. FIG. 4 is a schematic diagram showing a substrate before ink is landed and the state of the ink when a mask is not used, and more specifically, FIG. 4A is a plan view thereof, and FIG. b) is a cross-sectional view taken along the line AA. The state shown in FIG. 4 is the same as the state shown in FIG. However, the state immediately after the ink has landed differs between when the mask is used and when it is not used.

  FIG. 5 is a schematic diagram showing a substrate immediately after ink has landed and the state of the ink when a mask is not used. More specifically, FIG. 5A is a plan view thereof, and FIG. b) is a cross-sectional view taken along the line AA. In the state shown in FIG. 5, unlike the state shown in FIG. 2, only the ink 104a that is a part of the ink 104 is drawn into the surface of the pixel electrode 102, and the ink 104b that is the remaining part of the ink 104 Then, it is drawn into the surface of the pixel electrode adjacent to the pixel electrode 102 (in this case, adjacent to the right side).

  FIG. 6 is a schematic view showing a state of the substrate when all the ink is drawn on the pixel electrode when the mask is not used, and more specifically, FIG. 6A is a plan view thereof. FIG. 6B is a cross-sectional view taken along the line AA. As shown in the figure, the ink 104a spreads uniformly on the surface of the pixel electrode 102, and the ink 104b spreads on the surface of the pixel electrode adjacent to the pixel electrode 102. Therefore, when this substrate 101 is included in a display device such as an organic EL display device, problems such as color mixing, color misregistration, or variation in light emission efficiency occur.

  Here, the difference between the manufacturing process of the present invention using the inkjet method and a known vacuum deposition process will be described. In general, a vacuum deposition process using a mask may be employed as a method of manufacturing a display device using a low molecular organic EL element. Problems in this vacuum vapor deposition are mask shrinkage due to heat during vapor deposition, and warpage of the mask that occurs because the vapor deposition material attached to the mask has a different linear expansion coefficient from the mask. This impairs the positional accuracy when the deposit is patterned. Further, there is a problem in that the durability of the mask is lowered (life is shortened) due to adhesion of the deposited material to the mask. Furthermore, as a problem of this vacuum vapor deposition process, it is known that the film thickness of the vapor deposition differs between the vicinity of the central portion of the substrate immediately below the opening of the mask and the vicinity of the substrate edge due to the so-called shadowing effect. . Due to the above problems, it is difficult to manufacture a high-definition display device in a vacuum deposition process using a mask.

  However, since the inkjet method is used in the manufacturing method of the present invention, heat is not basically applied to the mask. Therefore, the mask does not shrink or warp. Even when the ink has landed on the mask surface, as long as the ink contacts the bank, the ink travels through the bank and slides (draws) onto the pixel electrode. Therefore, ink does not remain on the mask. Therefore, since the durability of the mask is improved, it is possible to reduce the manufacturing cost by repeatedly using the mask. Furthermore, since the projection effect does not occur in the manufacturing method of the present invention, the uniformity of the film thickness formed on the pixel electrode can be ensured. From the above points, it can be seen that the manufacturing process according to the present embodiment and the known vacuum deposition process differ not only in the presence / absence of banks and the configuration of the mask, but also in the effects and problems due to the use of the mask.

  Next, the properties and materials of the pixel electrode 102, the bank 103, the mask 106, and the ink 104 will be described in detail. First, the lyophilicity of the surface of the pixel electrode means that the surface free energy is higher than that of the bank and the mask, that is, the contact angle with respect to the ink is relatively large. In addition, the fact that the bank surface and the mask surface have liquid repellency means that the surface free energy is lower than that of the pixel electrode surface, that is, the contact angle with respect to ink is relatively small. Furthermore, since the value of the contact angle varies depending on the ink material, it is preferable to use the contact angle with water as an index.

  Here, the contact angles of the surface of the pixel electrode 102, the bank 103, and the mask 106 with respect to water were set to various values, and patterning with predetermined ink was performed, and the quality of the patterning was observed. The contact angle is measured using the drop method, which is a general measurement method, that is, a method in which a fixed volume of droplet is dropped on a measurement object and the contact angle is measured by a microscope or image processing. did. Moreover, Kyowa Interface Science Co., Ltd. contact angle meter CA-X was used as a measuring apparatus. As a result of observation, when the contact angle of water on the surface of the pixel electrode is larger than 20 degrees, the drawn ink is difficult to spread along the pattern, and when the contact angle of water on the bank surface and the mask surface is smaller than 60 degrees. All ink tends to remain on the bank surface or mask surface without being drawn into the pixel electrode surface. Therefore, when the contact angle of water on the pixel electrode surface is 20 degrees or less and the contact angle of water on the bank surface and the mask surface is 60 degrees or more, the ink is very good along the pattern formed by the bank. It can be patterned. Further, if the contact angle of water on the pixel electrode surface with water is 20 degrees or less, ink can be satisfactorily patterned on the pixel electrode surface even if the contact angle of water on the bank surface and mask surface is smaller than 60 degrees. If the contact angle of water on the surface and the mask surface with water is 60 degrees or more, it is preferable because the ink can be prevented from remaining even if the contact angle of water on the surface of the pixel electrode is larger than 20 degrees.

Next, as a technique for imparting lyophilicity to the surface of the pixel electrode 102, there is a technique of performing UV / O ₃ treatment or oxygen plasma treatment, which are known cleaning treatment methods, on the surface. By this method, organic (hydrocarbon) impurities are removed, and as a result, the lyophilicity of the pixel electrode surface can be enhanced.

  The material constituting the pixel electrode 102 is ITO, but of course, it is not limited to ITO, and may be another transparent conductive film such as IZO (Indium Zinc Oxide), When the substrate 101 is a substrate included in a top emission type organic EL display device, an opaque conductor, semiconductor, or the like can be appropriately used as a material constituting the pixel electrode 102. When the organic EL display device is an active drive type display device, a thin film transistor made of low-temperature polysilicon or CGS (Continuous Grain Silicon) is formed on the substrate 101 in advance. Even if it is electrically connected to the pixel electrode 102, there is no particular problem.

As a method for imparting liquid repellency to the surface of the bank 103, a bank material made of an organic material having no liquid repellency is formed on the substrate 101, and then CF ₄ (tetrafluoromethane) or CHF ₃ ( There is a method of performing plasma treatment using a fluorine-based gas such as trifluoromethane. In addition, since the material of the bank 103 contains fluorine or a silicon-based additive and has liquid repellency, the above process can be omitted. Furthermore, it is preferable to impart photosensitivity to the bank material because the bank 103 can be formed only by a process in which a resist is applied by spin coating or the like, followed by patterning by exposure, and then post-baking.

  The film thickness of the bank 103 is, for example, about 0.5 to 5 μm, but preferably about 1 to 3 μm. The planar shape of the bank 103 is a so-called oval shape as shown in FIG. 1A and the like, but is not limited to this shape, and patterning such as a circle, an ellipse, a rectangle, or a stripe is possible. Any shape may be used as long as it is necessary for this purpose.

  Further, the surface of the mask 106 needs to have liquid repellency similarly to the surface of the bank 103, but the same processing as the above processing for imparting liquid repellency to the bank 103 formed on the substrate 101. Therefore, it is the simplest process to provide liquid repellency by coating with a liquid repellent organic material. In addition, the end face of the opening of the mask 106, that is, the face of the mask 106 perpendicular to the plane along the substrate 101 (or the pixel electrode 102) preferably has the same liquid repellency as the mask surface (upper face). . Therefore, as a method for performing the coating, a method in which the mask 106 is immersed in a solution in which a resin having liquid repellency is dissolved and then dried is preferable.

  The mask 106 is preferably thin (for example, 0.2 mm or less, preferably 0.1 mm or less), and preferably has a high strength. The material of the mask 106 is not particularly limited as long as the above conditions are satisfied. For example, a metal such as stainless steel is preferable. Further, as a material of the mask 106, a material that is relatively strongly adsorbed to the magnet, for example, SUS410 (JIS standard) that is a martensitic alloy, SUS430 (JIS standard) that is a ferrite alloy, or the like is used. It is more preferable to dispose a permanent magnet on the back surface (lower surface) of 101 because the mask 106 can be brought into close contact with the bank 103 by magnetic force.

  The planar shape of the mask 106 includes the planar shape (pattern) of the bank 103 surrounding the target pixel electrode 102 for landing the ink in the opening, and is not a target adjacent pixel region, that is, a pixel. In general, the region in the vicinity of the pixel electrode adjacent to the electrode 102 must have a shape that is not exposed (on the upper surface). However, when the pattern of the bank 103 having the oval shape shown in FIG. 1A or the like is used, the two adjacent pixel regions (center positions thereof) are closer to the pattern than the minor axis direction of the pattern. Since those adjacent to each other in the major axis direction are considerably separated from each other, the landing accuracy in the major axis direction of the pattern is not so important as compared to the minor axis direction. In this case, the mask 106 may have a shape that hides (not exposes) only the pixel region adjacent in the minor axis direction, for example, a stripe shape.

  As the material of the ink 104, PEDOT / PSS (polyethylenedioxythiophene / polystyrene sulfonic acid), an aqueous dispersion of polyaniline or the like is used as a hole transport layer material, and poly-para-phenylene vinylene is used as a light emitting layer material. Polyfluorene, polyvinylcarbazole, polyarylene, polyspiro, and their derivatives dissolved in an aromatic solvent are used.

  Here, the shape of the mask 106 that does not expose adjacent pixel regions adjacent in the minor axis direction will be described. In addition, since it is the same also when adjacent to a long-axis direction, the description is abbreviate | omitted. FIG. 7 is a schematic diagram showing the relationship between the interval between banks and the width of the mask opening. The width Gm of the opening of the mask 106 in the short axis direction shown in FIG. 7 is equal to or wider than the gap Gb between the banks 103 in the short axis direction, that is, the maximum gap Gb in the short axis direction of the banks 103 sandwiching the pixel electrode 102. That is, it is preferable to set the relationship of Gb ≦ Gm, and when the width of the top of the bank 103 is W, it is preferable to set the relationship of Gm ≦ (Gb + 2W). By doing so, the bank opening in the adjacent pixel region is not exposed in the opening of the mask 106, so that the ink can be prevented from flowing into the adjacent pixel region. In addition, according to this configuration, since the peripheral edge of the opening of the mask 106 is not positioned on the inner side (pixel electrode side) than the top of the bank 103, a part of the ink 104 that contacts the mask 106 or the bank 103 is part of the pixel electrode. It becomes easy to start part of 102. Therefore, in a normal case, all of the ink 104 is drawn onto the pixel electrode 102, which is preferable. Further, if Gm≈ (Gb + W), even if the position of the periphery of the opening of the mask 106 is shifted in the width direction from the vicinity of the center of the top of the bank 103, as long as the distance indicating the shift does not exceed W / 2, The opening (pixel electrode) of the bank in the adjacent pixel region is not exposed in the opening of the mask 106, and the periphery of the opening of the mask 106 is located inside (on the pixel electrode side) from the top of the bank 103. Since there is no, it is more suitable.

  According to the conventional example shown in Patent Document 3, a mask is used for the patterning process. However, in this conventional configuration, since a gap is provided between the substrate and the mask, ink flows out to the adjacent pixel region. Moreover, since the opening width of the mask is narrower than the bank width, the liquid material (ink) does not contact the bank and the liquid material may not be drawn into the pixel electrode.

  Next, the shape near the top of the bank 103 will be described. The shape near the top of the bank 103 needs to be flat from the viewpoint of bringing the back surface (lower surface) of the mask 106 into close contact with the vicinity of the top of the bank 103. More specifically, it is preferable that the maximum width of the region where the height difference from the top of the bank 103 is within 0.5 μm is 2 μm or more. FIG. 8 is a schematic enlarged view of the vicinity of the top of such a bank. The bank 103 having the shape shown in FIG. 8 is in close contact with the mask 106, so that ink can be prevented from flowing into the adjacent pixel region.

  Next, an organic EL display device according to an embodiment of the present invention will be described with reference to FIG. FIG. 9 is a cross-sectional view schematically showing the structure of the organic EL display device. As shown in the figure, this organic EL display device is a bottom emission type, and includes a glass substrate 501, a pixel electrode 502, a bank 503, a hole transport layer 504, a light emitting layer 505, and an upper electrode (cathode). 506 and sealing glass 507 are provided. On the glass substrate 501, a pixel electrode 502 made of ITO and a bank 503 functioning as a partition wall are formed around the pixel electrode 502. Hole transport is performed on the pixel electrode 502 in the opening surrounded by the bank 503. A layer 504, a light emitting layer 505, and an upper electrode (cathode) 506 are sequentially stacked, and these are sealed with a sealing glass 507. A method for manufacturing an organic EL display device having such a structure will be described.

  First, an ink to be a hole transport layer (hereinafter referred to as “hole transport layer ink”) is applied in the opening of the bank 503 on the glass substrate 501 by the above-described inkjet method, and then dried. Thereby, the hole transport layer 504 is formed. The hole transport layer ink is an aqueous dispersion of PEDOT / PSS, and the solid content concentration is optimized according to the target film thickness after drying. The film thickness after drying is 20 to 150 nm, and more preferably 50 to 100 nm. Here, it is assumed that the film thickness after drying is 80 nm. In order to match the performance of the inkjet head used, the viscosity and surface tension may be adjusted by a technique such as adding alcohols to the hole transport layer ink.

  Subsequently, an ink to be a light emitting layer (hereinafter referred to as “light emitting layer ink”) is applied in the opening of the bank 503 by the above-described ink jet method, and then dried. As a result, the light emitting layer 505 is formed. The light emitting layer ink uses a polyfluorene polymer dissolved in an aromatic solvent, and the solid content concentration depends on the target film thickness after drying, similar to the hole transport layer ink. Assume that it is optimized. The film thickness after drying is 30 to 150 nm, and more preferably 50 to 100 nm. Here, it is assumed that the film thickness after drying is 80 nm. Further, when forming pixels of each color of RGB in this display device, the above process in which the position of the mask and the ink material are appropriately changed is performed three times.

  Next, a process for forming the upper electrode 506 is performed by a known method. The upper electrode 506 has a laminated structure of Ca as a low work function metal and Al as a cap electrode, and the film thickness of Ca is 10 nm and the film thickness of Al is 200 nm.

  Finally, sealing resin is used and sealing is performed with a sealing glass 507 that is a cap glass. Through this process, the bottom emission type organic EL display device is manufactured.

  In the organic EL display device produced as described above, even if it is high definition, unwanted ink does not land on the adjacent pixel area, so color mixing, color shift, variation in luminous efficiency, and the like are suppressed. The

FIG. 3 is a schematic diagram illustrating a substrate before ink is landed and the state of the ink in one embodiment of the present invention. FIG. 4 is a schematic diagram illustrating a substrate immediately after ink landing in the present embodiment and a state of the ink. It is a schematic diagram which shows the state of a board | substrate when all the ink is drawn in on the pixel electrode in this embodiment. It is a schematic diagram which shows the state of the board | substrate before ink landing, and the said ink in case the mask in this embodiment is not used. It is a schematic diagram which shows the board | substrate immediately after ink landing, and the state of the said ink in case the mask in this embodiment is not used. It is a schematic diagram which shows the state of a board | substrate when all the ink is drawn in on the pixel electrode in case the mask in this embodiment is not used. It is a schematic diagram which shows the relationship between the space | interval between banks in this embodiment, and the width | variety of a mask opening part. It is a typical enlarged view of the bank top part vicinity in this embodiment. It is sectional drawing which shows typically the structure of the organic electroluminescent display apparatus which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Substrate 102 ... Pixel electrode 103 ... Bank 104 ... Ink 105 ... Inkjet nozzle 106 ... Mask 501 ... Glass substrate 502 ... Pixel electrode 503 ... Bank 504 ... Hole transport layer 505 ... Light emitting layer 506 ... Upper electrode (cathode)
507 ... Sealing glass

Claims (14)

A method of manufacturing a substrate that performs predetermined patterning with a predetermined liquid material ejected by an inkjet method,
The vicinity of the periphery of the opening of the mask having an opening opened so as to expose a predetermined region of the substrate surrounded by the predetermined bank among the plurality of banks functioning as the partition walls formed on the substrate is the predetermined opening. A method of manufacturing a substrate, comprising: arranging the mask so as to be in close contact with a bank of the substrate, and discharging the liquid material into the opening.   The substrate manufacturing method according to claim 1, wherein a surface of the bank has a contact angle with water of 60 degrees or more.   The substrate manufacturing method according to claim 1, wherein the surface of the mask has a contact angle with water of 60 degrees or more.   The substrate manufacturing method according to claim 1, wherein the surface of the predetermined region of the substrate has a contact angle with water of 20 degrees or less. When the width Gm in the predetermined direction of the opening is Gb, the maximum interval in the predetermined direction of the bank sandwiching the predetermined region is Gb, and the width in the predetermined direction near the top of the bank is W,
Gb ≦ Gm ≦ (Gb + 2W)
The method for manufacturing a substrate according to claim 1, wherein:   2. The substrate according to claim 1, wherein the vicinity of the top of the bank has a shape in which a maximum width of a region in which a height difference from the top of the bank is within 0.5 μm is 2 μm or more. Manufacturing method.   The manufacturing method of the organic electroluminescent display apparatus characterized by including the manufacturing method of the board | substrate of any one of Claim 1- Claim 6. A substrate on which a predetermined patterning is performed by a predetermined liquid material ejected by an inkjet method,
A plurality of banks functioning as partition walls;
A predetermined region surrounded by a predetermined bank of the plurality of banks,
The liquid material discharged to the opening of the mask when the predetermined bank is disposed so that the vicinity of the periphery of the opening of the mask having the opening opened to expose the predetermined region is in close contact with the predetermined bank. A substrate characterized by functioning as a partition wall.   The substrate according to claim 8, wherein a surface of the bank has a contact angle with water of 60 degrees or more.   The substrate according to claim 8, wherein the surface of the mask has a contact angle with water of 60 degrees or more.   The substrate according to claim 8, wherein the surface of the predetermined region of the substrate has a contact angle with water of 20 degrees or less. When the width Gm in the predetermined direction of the opening is Gb, the maximum interval in the predetermined direction of the bank sandwiching the predetermined region is Gb, and the width in the predetermined direction near the top of the bank is W,
Gb ≦ Gm ≦ (Gb + 2W)
The substrate according to claim 8, wherein:   9. The substrate according to claim 8, wherein the vicinity of the top of the bank has a shape in which a maximum width of a region in which a height difference from the top of the bank is within 0.5 μm is 2 μm or more. .   An organic electroluminescence display device comprising the substrate according to any one of claims 8 to 13.

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