Self-luminous display panel manufacturing method and self-luminous display panel

A method of manufacturing a self-luminous display panel, includes: preparing a substrate; forming banks above the substrate; detecting a bank having a defect portion; determining, with respect to the detected bank, only one of two adjacent spaces as a repair target space; forming a dam structure in the repair target space; and forming light-emitting layers. The banks are elongated and extend in a column direction, and are arranged in a row direction with spaces therebetween. The two adjacent spaces are each located between the detected bank and an adjacent bank. The dam structure is located within a predetermined distance from the defect portion, and at least partially surrounds the defect portion or is composed of a pair of dam elements disposed with the defect portion therebetween in the column direction. The light-emitting layers are formed by applying inks to the spaces between the banks. The inks contain self-luminous materials.

This application claims priority to Japanese Patent Application No. 2017-163516 filed Aug. 28, 2017, the contents of which are hereby incorporated by reference in their entirety.

BACKGROUND

Technical Field

The present disclosure relates to a self-luminous display panel manufacturing method and a self-luminous display panel.

Description of Related Art

In recent years, organic EL display panels including a matrix of organic EL elements arranged above a substrate have been put into practical use, as one type of a self-luminous display device. Such organic EL display panels achieve high visibility due to the organic EL elements being self-luminous. Also, such organic EL display panels achieve excellent shock resistance due to the organic EL elements being completely solid-state elements.

Organic EL elements in a typical organic EL display panel have a basic structure in which a light-emitting layer containing an organic light-emitting material is disposed between an electrode pair composed of an anode and a cathode. The organic EL elements are driven through voltage application between these electrodes. The organic EL elements are current-driven light-emitting elements, emitting light when holes injected into the light-emitting layer from the anode and electrons injected into the light-emitting layer from the cathode recombine in the light-emitting layer.

In a typical organic EL display panel, a light-emitting layer of one organic EL element is partitioned from a light-emitting layer of an adjacent organic EL element by a bank formed by using an electrically-insulative material.

Further, in an organic EL element of a typical organic EL display panel, one or more organic layers, such as a hole injection layer, a hole transport layer, and a hole injection/transport layer, are disposed as necessary between the anode and the light-emitting layer. Likewise, one or more organic layers, such as an electron injection layer, an electron transport layer, and an electron injection/transport layer are disposed as necessary between the cathode and the light-emitting layer.

These organic layers, as well as the light-emitting layer, are commonly referred to as functional layers.

In a full-color organic EL display panel, a plurality of organic EL elements having a structure as described above are disposed, and each organic EL element serves as a red sub-pixel, a green sub-pixel, or a blue sub-pixel. Further, each pixel of a full-color organic EL display panel is composed of a set of red, green, and blue sub-pixels disposed next to one another.

The manufacturing of such an organic EL display panel involves a process of forming one or more organic functional layers, including the light-emitting layer, in spaces defined by banks, after forming the banks on the substrate. The forming of the organic functional layers is often performed through a wet process of applying, to the spaces, an ink containing a macro-molecular material or a low-molecular material suitable for forming a thin film, through an inkjet method or a similar method. Such a wet process enables organic functional layers to be formed relatively easily, even in large panels.

SUMMARY

A method pertaining to at least one aspect of the present disclosure is a method of manufacturing a self-luminous display panel. The method includes: preparing a substrate; forming banks above the substrate; detecting a bank having a defect portion among the banks; determining, with respect to the detected bank having the defect portion, only one of two adjacent spaces as a repair target space; forming a dam structure in the repair target space; and forming light-emitting layers. The banks are each elongated and each extend in a column direction, and are arranged in a row direction with spaces therebetween. The two adjacent spaces are each located between the detected bank and a bank adjacent to the detected bank in the row direction. The dam structure is located within a predetermined distance from the defect portion. The dam structure at least partially surrounds the defect portion, or is composed of a pair of dam elements disposed with the defect portion therebetween in the column direction. The light-emitting layers are formed by applying inks to the spaces between the banks. The inks contain self-luminous materials.

DETAILED DESCRIPTION

Process by which the Present Disclosure was Achieved

According to a manufacturing method of an organic EL display panel having the line bank structure, and banks, which are each elongated and each extend in a column direction, are formed above a substrate with spaces therebetween in a row direction, and light-emitting layers are formed by applying inks containing organic light-emitting materials to the spaces between the banks. The inks can flow within the spaces along the banks owing to the line bank structure, and this uniformizes film thickness which is ununiform at ink application. As a result, light-emitting layers having uniform film thickness can be formed. This yields an organic EL display panel with a reduced luminance unevenness. However, there is a possibility that when a bank has a defect portion, an ink, which is applied to one of two adjacent spaces that are each located between the bank having the defect portion and an adjacent bank, flows into the other space via the defect portion, and thus a color mixture region is produced in the other space due to inks of different light-emission colors mixing. Especially according to the line bank structure, a display element failure might occur over pixels due to the flow of mixed inks of different light-emission colors along banks.

One way to repair defect portions of banks having the line bank structure is for example a technique described in Japanese Patent Application Publication No. 2017-33813 according to which a dam structure at least partially surrounding a defect portion is formed in each of two adjacent spaces that are each located between a bank having the defect portion and an adjacent bank, thereby to prevent occurrence of a display element failure.

It can be expected that owing to formation of a dam structure at least partially surrounding a defect portion in each of two adjacent spaces that are each located between a bank having the defect portion and an adjacent bank, it is possible to prevent a color mixture region, where inks of different light-emission colors mix with one another, from spreading beyond the dam structure, thereby to reduce occurrence of a display element failure caused by light-emission in an undesired color. Unfortunately, formation of a dam structure might cause occurrence of a display element failure in which light is abnormally emitted from a subpixel where the dam structure has been formed. In other words, if a dam structure is formed in each of two adjacent subpixels that are each located between a bank having a defect portion and an adjacent bank, a display element failure might occur in each of the both two adjacent subpixels in which the dam structures have been formed.

Here, according to the specifications required for display devices, it may be permissible that a display element failure occurs in each of an extremely small number of isolated and discontinuous subpixels. Meanwhile, it may be impermissible that a display element failure occurs in each of two continuous subpixels.

In view of this, if a dam structure is formed in each of two adjacent spaces that are each located between a bank having a defect portion and an adjacent bank, the specifications required for display devices might be satisfied.

Here, even if a color mixture region is produced in a space, change in light-emission color in the color mixture region from the originally specified color is sometimes confined to a negligible degree as long as an extremely small amount of an ink of a different light-emission color flows into an adjacent space via the defect portion. Accordingly, it may be unnecessary to form such a dam structure at least partially surrounding a defect portion as long as an amount of an ink of a different light-emission color flowing into the space via the defect portion is confined to extremely small

On the other hand, by forming a dam structure in a space adjacent to a bank having a defect portion such that the dam structure at least partially surrounds the defect portion, an ink applied inside a region defined by the dam structure in the space can be prevented from spreading beyond the dam structure, and an ink applied outside the range can be prevented from flowing into the range. This confines an ink flowing from the space into an adjacent space via the defect portion to at most an amount applied inside the region defined by the dam structure.

In view of this, by forming a dam structure at least partially surrounding a defect portion in only one of two adjacent spaces that are each located between a bank having the defect portion and an adjacent bank, an amount of an ink, which flows from the one space in which the dam structure has been formed into the other space in which no dam structure has been formed, can be confined. Owing to this structure, if a color mixture occurs in the other space in which no dam structure has been formed, the color mixture only exercises an effect to an almost negligible degree, and thus no display element failure occurs in any subpixel in the other space. It is true that a display element failure might occur in a subpixel corresponding to the dam structure, but no display element failure occurs in any subpixel in the other space adjacent to the one space with the defect portion therebetween. This confines occurrence of a display element failure to only the isolated subpixel corresponding to the one space in which the dam structure has been formed.

Through the above process, the present inventor arrived at the present disclosure according to which occurrence of a display element failure caused by a bank defect portion is confined to each isolated subpixel.

As described above, for a full-color organic EL display panel, inks corresponding to different colors of light are applied to adjacent spaces partitioned by a bank. Here, if the bank between the adjacent spaces has a defect portion having been produced in the manufacturing process of the organic EL display panel, ink applied to one space may leak into the adjacent space via the defect portion in the process of forming light-emitting layers. This results in color mixture in which inks corresponding to different light-emission colors mixing with one another. Note that in the present disclosure, it is considered that a bank defect portion is produced when, for example, a portion of a bank collapses or a foreign particle adheres to a bank in the manufacturing process of the organic EL display panel.

When an organic EL display device is manufactured using a panel in which such color mixture has occurred, display element failures may appear in the manufactured organic EL display device. That is, for example, the region of the organic EL display device where color mixture has occurred may emit light with an undesired color, or may be perceived as a dark spot.

In view of this, there is a demand for a technology of repairing banks having defect portions and thereby preventing such display element failures from occurring in display panels.

The present disclosure includes a self-luminous display panel manufacturing method and a self-luminous display panel that prevent display element failures from occurring even if a bank defect portion is produced in the manufacturing process of the self-luminous display panel.

Overview

A method pertaining to at least one aspect of the present disclosure is a method of manufacturing a self-luminous display panel. The method includes: preparing a substrate; forming banks above the substrate; detecting a bank having a defect portion among the banks; determining, with respect to the detected bank having the defect portion, only one of two adjacent spaces as a repair target space; forming a dam structure in the repair target space; and forming light-emitting layers. The banks are each elongated and each extend in a column direction, and are arranged in a row direction with spaces therebetween. The two adjacent spaces are each located between the detected bank and a bank adjacent to the detected bank in the row direction. The dam structure is located within a predetermined distance from the defect portion. The dam structure at least partially surrounds the defect portion, or is composed of a pair of dam elements disposed with the defect portion therebetween in the column direction. The light-emitting layers are formed by applying inks to the spaces between the banks. The inks contain self-luminous materials.

The following describes at least one embodiment of a display panel as at least one aspect of the present disclosure with reference to the drawings.

Embodiments

[Overall Structure of Organic EL Display Device]

FIG. 1is a schematic block diagram illustrating the structure of an organic EL display device1having a display panel100pertaining to at least one embodiment.

InFIG. 1, the organic EL display device1includes the display panel100and a drive controller101connected thereto. The display panel100is a panel using the electroluminescence effect of an organic material. In the display panel100, light-emitting elements (organic EL elements)10are arranged above a substrate to form a matrix inFIG. 2. The drive controller101includes four drive circuits, namely drive circuits102,103,104, and105, and a control circuit106.

The arrangement of the drive controller101with respect to the display panel100is not limited to that illustrated inFIG. 1.

[Structure of Organic EL Display Panel]

FIG. 2is a schematic plan view illustrating the overall structure of the display panel100pertaining to at least one embodiment, when viewed in plan from above a display surface thereof.FIG. 3is a cross-sectional view illustrating a part of the display panel100pertaining to at least one embodiment, taken along line A-A′ ofFIG. 2, in magnified state. The display panel100is a so-called top-emission-type panel, and the display surface of the display panel100is located in the Z direction inFIG. 3.

The following describes the structure of the display panel100, with reference toFIG. 2andFIG. 3.

InFIG. 3, the display panel100includes, as main components thereof, a ground substrate11, pixel electrodes12, a hole injection layer13, first banks14, organic light-emitting layers15, an electron transport layer16, a common electrode17, and a sealing layer18.

The hole injection layer13, the organic light-emitting layers15, and the electron transport layer16are functional layers, and thus, the functional layers are disposed between the pixel electrodes12and the common electrode17.

Each light-emitting element10includes an organic light-emitting layer15of a corresponding light-emission color. That is, the light-emitting elements10R,10G, and10B include organic light-emitting layers15of the colors red (R), green (G), and blue (B), respectively. Each light-emitting element10serves as a sub-pixel of the display panel100, and sub-pixels are arranged to form a matrix in the display panel100inFIG. 2.

FIG. 2illustrates a state where the electron transport layer16, the common electrode17, and the sealing layer18are removed.

The ground substrate11includes a substrate body11a,thin-film transistor (TFT) layers11b,and an interlayer insulation layer11c.

The substrate body11aserves as the base of the display panel100, and may be formed by using, for example, an electrically-insulating material such as non-alkali glass, soda glass, polycarbonate resin, polyester resin, or aluminum oxide. Alternatively, the substrate body11amay be formed by using a polyimide material.

The TFT layers11bare provided one-to-one for sub-pixels of the display panel100, on the surface of the substrate body11a. Each TFT layer11bhas formed therein a pixel circuit that includes a TFT element.

The interlayer insulation layer11cis formed on the TFT layers11b.The interlayer insulation layer11cis formed by using an organic electrically-insulating material such as a polyimide resin, an acrylic resin, or a novolac-type phenol resin, or an inorganic electrically-insulating material such as SiO (silicon oxide) or SiN (silicon nitride). The interlayer insulation layer11csecures electrical insulation between the TFT layers11band the pixel electrodes12. In addition, the interlayer insulation layer11cplanarizes any level difference on the top surfaces of the TFT layers11b,and thereby suppresses the influence that such level differences would otherwise have with respect to the surface on which the pixel electrodes12are formed.

Pixel Electrodes

The pixel electrodes12are provided one-to-one for sub-pixels of the display panel100, on the ground substrate11. The pixel electrodes12are formed by using an optically-reflective electrically-conductive material, such as Ag (silver), Al (aluminum), aluminum alloy, Mo (molybdenum), or APC (an alloy of silver, palladium, and copper). According to at least one embodiment, the pixel electrodes12serve as anodes.

A conventional light-transmissive electrically-conductive film may be additionally provided on the surface of each pixel electrode12. This light-transmissive electrically-conductive film may be formed by using, for example, indium tin oxide (ITO) or indium zinc oxide (IZO). The light-transmissive electrically-conductive films are disposed between the pixel electrodes12and the hole injection layer13, and improve inter-layer joining.

Hole Injection Layer

The hole injection layer13is formed, for example, by using an oxide of a metal such as silver (Ag), molybdenum (Mo), chromium (Cr), vanadium (V), tungsten (W), nickel (Ni), or iridium (Ir), or an electrically-conductive polymer material such as PEDOT (a mixture of polythiophene and polystyrene sulfate). The hole injection layer13, when formed by using a metal oxide, assists hole generation and ensures stable injection and transportation of holes to the organic light-emitting layers15.

Banks

A plurality of linear first banks14are provided on the surface of the hole injection layer13. In plan view, each of the first banks14is elongated and extends in the Y direction, and has a rectangular shape. The first banks14are formed by using an organic electrically-insulative material (for example, an acrylic resin, a polyimide resin, or a novolac-type phenol resin).

InFIG. 3, each of the first banks14has a trapezoidal cross-section. Further, a pair of first banks14defines a space20, whereby a plurality of spaces20(spaces20R,20G,20B) are partitioned from one another by the first banks14. At the bottom portion of each space20, a plurality of pixel electrodes12are arranged along the Y direction, and above the pixel electrodes12, functional layers are disposed. The functional layers include the hole injection layer13, the organic light-emitting layers15, and the electron transport layers16.

The first banks14partition light-emitting elements10that are adjacent in the X direction from one another, and also serve as structural members that, when a wet process is performed for forming the organic light-emitting layers15, prevent applied ink from overflowing.

InFIG. 2, the display panel100also includes a plurality of second banks24. The second banks24have smaller height than the first banks14inFIG. 7. Further, a plurality of second banks24are disposed in each space20between pixel electrodes12that are adjacent in the Y direction. The second banks24partition light-emitting elements10that are adjacent in the Y direction from one another. As such, the display panel100is an organic EL display panel that has the so-called line bank structure.

The second banks24are disposed at the same Y-direction positions in every space20. Each second bank24connects with adjacent second banks24by extending in the X direction below first banks14, and thus, when viewed as a whole, each second bank24has a rectangular shape elongated in the X direction. Accordingly, the first banks14and the second banks24form a lattice structure over the ground substrate11inFIG. 2.

The organic light-emitting layers15emit light through recombination of carriers (i.e., holes and electrons) occurring therein, and each contain an organic material corresponding to one of the colors R, G, and B.

The organic light-emitting layers15are disposed in the spaces20(refer to the spaces20R,20G, and20B illustrated inFIG. 7AandFIG. 7B), which are partitioned from one another by the first banks14, are elongated and extend in the Y direction, and have groove-like shapes.

InFIG. 7AandFIG. 7B, each space20R is a space in which light-emitting layers of the color R will be formed and thus, light-emitting elements10R corresponding to the color R will be formed. Similarly, each space20G is a space in which light-emitting layers of the color G will be formed and thus, light-emitting elements10G corresponding to the color G will be formed, and each space20B is a space in which light-emitting layers of the color B will be formed and thus, light-emitting elements10B corresponding to the color B will be formed.

As such, each first bank14is disposed between two of organic light-emitting layers15, which differ in terms of color.

The electron transport layer16transports electrons injected thereto from the common electrode17to the organic light-emitting layers15, and is formed by using, for example, an oxidiazole derivative (OXD), a triazole derivative (TAZ), or a phenanthroline derivative (BCP, Bphen).

Common Electrode

The common electrode17is formed by using, for example, a light-transmissive material having electrically-conductive properties, such as ITO or IZO. The common electrode17extends across all sub-pixels of the display panel100.

According to at least one embodiment, the common electrode17serves as a cathode.

The sealing layer18is disposed to protect the hole injection layer13, the organic light-emitting layers15, the electron transport layer16, and the common electrode17from water and oxygen.

Although not depicted in the drawings, black matrices, color filters, and/or the like may also be formed above the sealing layer18.

FIG. 4is a schematic diagram illustrating a manufacturing process of the display panel100pertaining to at least one embodiment.

FIG. 5AthroughFIG. 5Eare schematic cross-sectional views each illustrating a procedure of the manufacturing process of the display panel100pertaining to at least one embodiment.

The manufacturing method of the display panel100is described in accordance withFIG. 4, which illustrates the procedures involved in the manufacturing process, and with further reference toFIG. 3andFIG. 5AthroughFIG. 5E.

First, the TFT layers11bare formed on the substrate body11a(Step S1).

Subsequently, the interlayer insulation layer11cis formed on the TFT layers11bby using an organic material providing excellent electrical insulation and through a photoresist method, with which the preparation of the ground substrate11is completed (step S2). The thickness of the interlayer insulation layer11cis approximately 4 μm, for example. Although not depicted in the cross-sectional view ofFIG. 3nor inFIG. 4, which illustrates the procedures involved in the manufacturing process, contact holes2(seeFIG. 2) are also formed during the forming of the interlayer insulation layer11c.

Next, the pixel electrodes12are formed, one for each sub-pixel, from a metallic material having a thickness of approximately 400 nm, through vacuum vapor deposition or sputtering (Step S3).

Then, the hole injection layer13is formed by uniformly forming a film of tungsten oxide above the ground substrate11and the pixel electrodes12through sputtering or the like (Step S4).

Subsequently, the first banks14and the second banks24are formed through photolithography (Step S5), as described in the following.

First, bank material (e.g., a photosensitive photoresist material) for forming the second banks24is applied uniformly above the hole injection layer13.

Then, a photomask having openings matching the pattern of the second banks24is placed over the layer of the applied bank material, and developing is performed through UV irradiation. Subsequently, an unhardened and excess portion is removed from the bank material by using a developing fluid, thereby to form unfired second banks24a.Then, the unfired second banks24aare heated and fired. This completes the second bank24.

Subsequently, bank material (e.g., a negative photosensitive resin composition) for forming the first banks14is applied uniformly above the substrate above which the second banks24have been formed.

Then, bank patterning is performed by placing a mask having openings matching the pattern of the first banks14over the layer of the applied bank material, and performing irradiation with light from above the mask. The pattern of the first banks14is completed by washing away an excess portion from the bank material with an alkaline developing fluid thereby to pattern the bank material.

Unfired first banks14aare formed as a result of such patterning, after the second banks24have been formed, inFIG. 5A. At this point, a space20has already been formed between each pair of adjacent unfired first banks14a.

Next, the unfired first banks14a,formed through the above-described patterning, are examined to detect defect portions (Step S6). Any defect portion detected is repaired.

The bank repair is described in more detail later. Broadly speaking, a defect portion of an unfired first bank14ais repaired by forming a dam structure, in the vicinity of the defect portion, in one of two adjacent spaces20that are each located between the unfired first bank14ahaving the defect portion and an adjacent unfired first bank14a(Step S7). The dam structure is formed by applying a repair material to the one space and then drying the applied repair material.FIG. 5Billustrates a state where unfired dam elements52ahave been formed by applying a repair material to one of two adjacent spaces20that are each located between an unfired first bank14ahaving a defect portion and an adjacent unfired first bank14a.

Then, first banks14and dam elements52are respectively produced by thermal firing of the unfired first banks14aand the unfired dam elements52a,thereby completing the repair of the defect portion3(Step S8). The firing is, for example, performed by heating the unfired first banks14aand the unfired dam elements52aat a temperature between 150° C. and 210° C. for 60 minutes.

FIG. 5Cillustrates a state where the dam elements52, as well as the first banks14, have been formed by this firing, or in other words, a state where any defect portion3of the first banks14has been repaired.

The first banks14formed in this manner may be further subjected to a process of adjusting contact angle with respect to ink to be applied in the subsequent procedure. Alternatively, in order to provide liquid repellency to the surfaces of the first banks14, processing such as surface processing using a predetermined alkaline solution, water, an organic solvent, etc., or plasma processing may be performed. Note that, in order to provide liquid repellency to the first banks14, the bank material for forming the first banks14may be liquid-repellent.

Although the unfired first banks14and the unfired dam structures50are simultaneously fired in this example, the first banks14and the dam structures50may be separately fired. In other words, the first banks14and the dam structures50may be formed as follows. Specifically, in this example, formation of the unfired first banks14, detection of the defect portions3, formation of the unfired dam structures50, and firing of the unfired first banks14and the unfired dam structures50are performed in the stated order. Alternatively, these processes may be performed in the following order of formation of the unfired first banks14, firing of the unfired first banks14, detection of the defect portions3, formation of the unfired dam structures50, and firing of the unfired dam structures50.

Next, inks for forming the organic light-emitting layers15are applied to the spaces20inFIG. 5D. Each ink is a mixture of an organic material for the corresponding organic light-emitting layers15and a solvent, and is applied to the inside of spaces20using an inkjet method. The details are described later on a method of applying inks to the inside of the spaces20using the inkjet method.

Ink layers15aformed through the ink application are then dried by evaporating the solvent contained in the ink layers15a,and thermal firing is performed when necessary. Thus, the organic light-emitting layers15are formed in the spaces20inFIG. 5E(Step S9).

Next, the electron transport layer16is formed above the organic light-emitting layers15and the first banks14by depositing a film of a material for the electron transport layer16through vacuum vapor deposition (Step S10).

The common electrode17is then formed by depositing a film of a material such as ITO or IZO through sputtering or the like (Step S11).

Then, the sealing layer18is formed by depositing a film of a light-transmissive material such as SiN or SiON on the surface of the common electrode17through sputtering, CVD, or the like (Step S12).

The manufacturing of the display panel100is completed through the above-described procedures.

Method of Applying Inks to Inside of Spaces20using Inkjet Method

The following describes the details of the method of applying the inks for forming the organic light-emitting layers15to the inside of the spaces20using the inkjet method.

In application of the inks for forming the organic light-emitting layers15, a solution for forming the organic light-emitting layers15is applied by using an ink discharge device. An ink application process is repeated for each of three-color inks. Specifically, one of respective three-color inks for forming red, green, and blue light-emitting layers is applied to the substrate. Next, another one of the three-color inks is applied to the substrate. Lastly, the last one of the three-color inks is applied to the substrate. In this way, the three-color inks are applied in order. As a result, the red, green, and blue light emitting-layers alternate over the substrate.

FIG. 6is a schematic diagram illustrating a process of applying inks for forming light-emitting layers to the substrate pertaining to at least one embodiment, with respect to a case where the inks are uniformly applied to spaces20between first banks14.

In formation of the light-emitting layers15, red light-emitting layers15R, green light-emitting layers15G, and blue light-emitting layers15B are respectively formed in spaces20R for red subpixels, spaces20G for green subpixels, and spaces20B for blue subpixels in the regions defined by the banks having the line bank structure, with use of the ink layers15a,which are solutions for forming the light-emitting layers15. Note that the light-emitting layers15R may differ in thickness from the light-emitting layers15G and/or15B. The light-emitting layers15R can be formed so as to have a greater thickness than the light-emitting layers15G and15B by using, for example, an ink with a larger application amount for the spaces20R than ones for the spaces20B and/or20G.

For the purpose of simplifying the description, ink application is sequentially performed with respect to all the spaces corresponding to first, second, and third colors in the following manner. Specifically, under a first condition for ink discharge amount from the nozzles, ink application is performed with respect to spaces20corresponding to the first color above the substrate. Then, under a second condition for ink discharge amount from the nozzles, ink application is performed with respect to spaces20corresponding to the second color above the substrate. Lastly, under a third condition of ink discharge amount from the nozzles, ink application is performed with respect to spaces20corresponding to the third color above the substrate. Note that different nozzles for ink discharge may be used for each of the first, second, and third ink colors.

(Method of Uniformly Applying Inks to Spaces20between First Banks14)

The following describes a method of applying each of the three-color inks to spaces corresponding to the ink color (for example, the red ink for spaces corresponding to the red color).

The light-emitting layers15extend continuously not only over luminous regions (regions surrounded by the first banks14and the second banks24inFIG. 2) but also over non-luminous regions (regions above the second banks24inFIG. 2) which are disposed between the luminous regions. With this configuration, when forming the light-emitting layers15, ink applied to the luminous regions can flow in the column direction via ink applied to the non-luminous regions, and thus film thickness between pixels in the column direction can be uniformized. Accordingly, it is unlikely that a large degree of film thickness unevenness occurs in the column direction, and thus luminance evenness between pixels and service life are improved.

According to this application method, the substrate is placed on a work table of the ink discharge device such that the first banks14are arranged in the Y direction. Then, application is performed by, while scanning in the X direction with use of an ink jet head301having discharge ports3031arranged in line in the Y direction, discharging ink from the discharge ports3031toward arrival targets that are set in the spaces20between the first banks14.

Note that the ink for forming the light-emitting layers15with an equal application amount is applied to every three regions that are adjacent to each other in the X direction.

Here, the method of forming the light-emitting layers15is not limited to this method. Other commonly-known methods besides the inkjet method and a gravure printing method may be used for ink discharge and application. Such commonly-known methods include a dispenser method, a nozzle coating method, a spin coating method, an intaglio printing method, and a relief printing method.

[Method of Detecting and Repairing Defect Portion]

As described above in connection with the manufacturing method, but in more precise terms, the first banks14and the dam elements52are respectively formed by thermal firing and curing of the unfired first banks14aand the unfired dam elements52ahaving been formed. However, the unfired first banks14aand the unfired dam elements52aare somewhat solidified and already have stable shapes. As such, in the present disclosure, description is provided while simply referring to the unfired first banks14aand the unfired dam elements52aby using the terms first banks14aand dam elements52a,respectively.

First, a defect portion3of a first bank14ais described.

A defect portion3of a first bank14amay be a foreign particle present at the first bank14a,or may be a missing portion of the first bank14a.

The foreign particle may be, for example, a piece of metal originating in manufacturing equipment, or dust or dirt originating in the atmosphere. The dust or dirt tends to be a piece of fabric.

FIG. 7Ais a schematic perspective view illustrating an example in which a foreign particle has adhered onto one first bank14aand has become a defect portion3pertaining to at least one embodiment.FIG. 7Bis a schematic perspective view illustrating a state where a dam structure50, which is composed of a pair of dam elements52disposed with the defect portion3therebetween in the Y direction, has been formed pertaining to at least one embodiment. As such, according to at least one embodiment, a dam structure50is composed of a pair of dam elements52disposed with the defect portion3therebetween in the Y direction. Further, one pair of dam elements52is disposed in one of two adjacent spaces20that are each located between the first bank14ahaving the defect portion3and an adjacent first bank14a,and the dam elements52composing the pair extend in the X direction from two points on the first bank14ahaving the defect portion3to an adjacent first bank14a.

Further, the plan-view width of the dam elements52is for example between 5 μm and 50 μm.

When dome-shaped ink layers15aare formed inFIG. 5Dby applying ink to two adjacent spaces20that are each located between a first bank14aon which a foreign particle is present and an adjacent first bank14a,there is a risk of the ink layers15acoming in contact with the foreign particle. Consequently, some of the ink applied to each of the spaces20may flow into the other adjacent space20, which results in inks of different light-emission colors (e.g., red ink and green ink) mixing.

According to at least one embodiment, a dam structure50is formed in one of two adjacent spaces20that are each located between a first bank14having a foreign particle and an adjacent first bank14. Thus, in the one adjacent space20, the dam structure50stops a mixed ink from spreading any further, and thereby prevents a color mixture region from spreading any further. Furthermore, the dam structure50prevents an ink applied outside a region defined by the dam structure50from coming in contact with the foreign particle and thus flowing into the other adjacent space20.

Note that the defect portion3need not be a foreign particle having adhered onto the first bank14asuch as above. For example, inFIG. 8A, the defect portion3may be a foreign particle that has entered the inside of the first bank14aand penetrates through a wall surface of the first bank14from one space20to an adjacent space20. For example, inFIG. 8B, the defect portion3may be a foreign particle that has slipped beneath the first bank14aand penetrates the first bank14afrom one space20to an adjacent space20. With a foreign particle inside or beneath a first bank14a,a gap serving as an ink flow channel may be formed in the first bank14a,given poor adhesion between the foreign particle and the bank material. Particularly, when the foreign particle is a piece of fabric, the foreign particle itself unfortunately serves as an ink flow channel by absorbing ink. As such, even when the defect portion3is a foreign particle inside or beneath a first bank14a,the defect portion3may bring about color mixture between ink layers15aformed in two adjacent spaces that are each located between the first bank14ahaving the foreign particle and an adjacent first bank14a.

Further, inFIG. 8C, a portion of one first bank14ahas collapsed and has become a defect portion3. A portion of a first bank14amay collapse in such a manner, for example, when a portion of a bank material layer not having undergone sufficient polymerization in the bank material layer light exposure process, due to not being exposed to enough light, is washed away during the subsequent developing process. Even when the defect portion3is a collapsed portion of the first bank14a,the collapsed portion may mediate color mixture between ink layers15aformed in two adjacent spaces that are each located between the first bank14ahaving the collapsed portion and an adjacent first bank14a.

As described above, mixture of inks of different light-emission colors occurs at a portion of a first bank14awhere a foreign particle is present and at a collapsed portion of a first bank14a,and the mixture of such inks may lead to light-emission in an undesired color. As such, such portions of first banks14aare referred to as defect portions3of the first banks14a.

[Detection of Defect Portion3and Forming of Dam Structures50]

The detection of a defect portion3of a first bank14ais performed by, for example, capturing an image of the surfaces of the first banks14aformed above the ground substrate11, and performing a pattern search on the image.

FIG. 9is a schematic view illustrating the overall structure of one example of a repair device used for detecting and repairing bank defect portions pertaining to at least one embodiment.

The repair device illustrated inFIG. 9(repair device200) includes a base201, and a table202and a head portion210above the base201. The table202is a table on which the ground substrate11is placed. The head portion210has attached thereto an image capture element211and a needle dispenser213. The table202is moveable along the Y direction in accordance with an instruction from a CPU231of a controller230. The head portion210is likewise moveable along the X direction and the Z direction in accordance with an instruction from the CPU231.

Accordingly, in accordance with an instruction from the CPU231, the needle dispenser213, which is attached to the head portion210, is capable of moving above the ground substrate11and in the X direction, the Y direction, and the Z direction relative to the ground substrate11, which is placed on the table202.

Here, the ground substrate11is in a state where the pixel electrodes12, the hole injection layer13, the first banks14a,and the second banks24ahave already been formed above the ground substrate11.

FIG. 10Ais a schematic plan view illustrating forming position of a dam structure50pertaining to at least one embodiment.FIG. 10Bis a schematic plan view illustrating a state where dam elements52have been formed pertaining to at least one embodiment.

As such, each of dam elements52in any space20is formed by using the needle dispenser213and applying the repair material to a plurality of predetermined positions set along a line (dam forming line) on which the dam element52is to be formed.

InFIG. 10A, when a defect portion3is detected on a first bank14a, coordinates positions indicating end portions of the defect portion3(a foreign particle in this example) in the Y direction are acquired. A dam forming line is set on each of two adjacent second banks24that are the closest to the acquired coordinate positions and sandwich the defect portion3therebetween in the Y direction. Points P1, P2, P3, and P4illustrated inFIG. 10Aindicate application positions by the needle dispenser that are set along the dam forming lines.

FIG. 11AthroughFIG. 11Gare diagrams illustrating how a dam element52is formed by applying the repair material to the application points P1, P2, P3, and P4, one after another pertaining to at least one embodiment.

The repair device200forms a dam element52by applying the repair material to the application points P1, P2, P3, and P4, which have been set as described above, one after another by using a needle213a.The needle dispenser213has a tank213battached at a tip portion thereof. The tank213bstores the repair material. The needle dispenser213is capable of applying the repair material in microliter units by moving the needle213aup and down through the tank213bto cause the repair material to adhere to the needle213a.

First, inFIG. 11AandFIG. 11B, with the needle213aand the tank213bpositioned above application point P1, the needle213ais moved downward so that the repair material adheres to the needle213a.Then, the needle213ais moved toward application point P1to apply the repair material to application point P1.

The repair material has fluidity until application. However, after application, the repair material maintains a mound shape. Thus, inFIG. 11C, a mound of the repair material is formed at application point P1.

Subsequently, inFIG. 11D, the needle213ais withdrawn upwards into the tank213b,and the needle213aand the tank213bare moved to application point P2. Subsequently, inFIG. 11E, the needle213ais moved downward so that the repair material adheres to the needle213a,and then the needle213ais moved toward application point P2to apply the repair material to application point P2.

Then, the mound of the repair material that is formed at application point P2connects to the mound of the repair material having been formed at application point P1inFIG. 11F.

Then, inFIG. 11G, the needle213ais withdrawn upwards and moved to application point P3.

Then, in a similar manner as described above, a mound of the repair material is formed at application point P3, which connects to the mound of the repair material having been formed at application point P2. Further, a mound of the repair material is formed at application point P4, which connects to the mound of the repair material having been formed at application point P3.

As such, mounds of the repair material are formed continuously on a line extending from a point on the first bank14ahaving the defect portion3to an adjacent first bank14a.Then, the mounds of the repair material so applied are dried and exposed to light as needed, thereby forming a dam element52.

Note that the subsequent simultaneous firing process causes the repair material so applied to harden. Thus, the dam element52is provided with even higher physical stability.

By executing the process described above for two dam elements52, a dam structure50is formed.

Through the above-described dam structure forming process, a pair of dam elements52is formed in one of two adjacent spaces20that are each located between a first bank14having a defect portion3and an adjacent first bank14inFIG. 7B. The dam elements52partition the space20into a first space SA in the vicinity of the defect portion3and two second spaces SB outside the vicinity of the defect portion3.

When the subsequent light-emitting layer forming process of Step S9(refer toFIG. 4) is performed after repairing any defect portion3of the first banks14in such a manner, ink is applied to the first space SA and the second spaces SB while ink mixture is confined within a specific region as described in detail later, thus forming organic light-emitting layers15.

Note that the repair material may be any resin composition that hardens when exposed to light, heat, or the like.

The resin may be, for example, a curable resin containing an ethylene double bond, such as a (meth) acryloyl group, an aryl group, a vinyl group, or a vinyloxy group.

Also, a cross-linking agent, such as an epoxy compound or a polyisocyanate compound, that forms a cross-link with the resin may also be contained in the repair material as an additive.

The resin in the repair material may be a fluoride polymer, in which fluoride atoms are included in the resin structure. Using resin including fluoride atoms as the repair material provides liquid repellency to dam structures50formed by using the repair material. Alternatively, various liquid repellent agents may be added to the resin. In any case, the content of the liquid repelling agent should be between 0.01 wt % and 10 wt %. Adding a liquid repelling agent by an amount within this range ensures that the resin compound is stable during storage, and also provides dam structures50formed by using the repair material with high liquid repellency.

Also, the same material as the bank material used for forming the first banks14amay be used as the repair material.

Further, the resin composition in the repair material may contain a solvent and a photopolymerization initiator as additives, when necessary.

The solvent may be one or more types of solvents that have solubility in resins and have a boiling point approximately within the range between 150° C. and 250° C.

The photopolymerzation initiator may be any type of photopolymerization initiator available on the market.

Further, upon the application of the repair material, the repair material is adjusted so that the content of solid components in the repair material is between, for example, 20 wt % and 90 wt %, and the repair material has a viscosity between, for example, 10 cP and 50 cP (where cP is the unit centipoise).

Further, the amount of the photopolymerzation initiator added is adjusted in accordance with the amount of light exposure in the light exposure process performed before the firing process. For example, the amount of the photopolymerzation initiator added is to be adjusted such that the content of the photopolymerzation initiator with respect to the total solid component of the repair material is between 0.1 wt % and 50 wt % in at least one embodiment, and is between 5 wt % and 30 wt % in at least one embodiment.

[Effect of Forming Dam Structures50]

The following describes the spread of a color mixture region with reference to comparison between a case where a dam structure50is formed and a case where no dam structure50is formed.

FIG. 12Ais a plan view illustrating a state where, in a display panel pertaining to at least one embodiment, a pair of dam elements52has been formed around a first bank14having a defect portion3, and an ink layer15a(R) has been formed in one of two adjacent spaces20that are each located between the first bank14having the defect portion3and an adjacent first bank14, through the application of red ink and an ink layer15a(G) has been formed in the other one of the two adjacent spaces20through the application of green ink. Meanwhile,FIG. 12Bis a plan view illustrating a state where, in a comparative example pertaining to at least one embodiment in which dam structures50are not formed, an ink layer15a(R) and an ink layer15a(G) have been formed in two adjacent spaces20that are each located a first bank14having a defect portion3and an adjacent first bank14.

InFIG. 12B, without the dam structures50formed around the defect portion3, the red ink and the green ink mix via the defect portion3and produce, in each of the two ink layers15a,a color mixture region that extends in the Y direction. This color mixture region extends far in the Y direction, and the length thereof may extend to around several centimeters.

Once the manufacturing of the display panel100is completed, these color mixture regions emit light having a color different from the originally specified color.

Note that in the case where a color filter is provided, an unnecessary color of the light is cut, allowing observation of the originally specified color. However, the luminance of the light through the color filter might decrease. Furthermore, once the manufacturing of the display panel100is completed, the light-emitting layers in the color mixture regions tend to have an undesired film thickness, and accordingly exhibit undesired luminous efficiency, voltage, and so on.

InFIG. 12Acompared with this, a dam structure50, which is composed of a pair of dam elements52, has been formed in a space20G to which a green ink is applied among two adjacent spaces20that are each located between a first bank14having a defect portion3and an adjacent first bank14. InFIG. 12A, even if a color mixture region is produced in a region defined by the dam structure50, the color mixture region cannot spread beyond the dam elements52. Also, an amount of the green ink, which is applied to the space20G in which the dam structure50has been formed, flowing via the defect portion3into the adjacent space20R to which a red ink is applied, is confined to at most an amount applied inside the region defined by the dam structure50. In other words, even if the green ink, which is applied inside the region defined by the dam structure50, flows into the adjacent space20R via the defect portion3, the green ink applied outside the range cannot flow into the adjacent space20R via the defect portion3.

InFIG. 12A, the color mixture region extends far in the Y direction in the space20to which the red ink is applied among the two adjacent spaces, which are each located between the first bank14having the defect portion3and the adjacent first bank14. This is similar to the comparative example where no dam structure50has been formed around the defect portion3. However, owing to the small green-ink amount flowing via the defect portion3, change in light-emission color in the color mixture region in the space20R from the originally specified color is confined to a negligible degree, as described above.

Thus, by forming a dam structure50in only one of two adjacent spaces20that are each located between a first bank14having a defect portion3and an adjacent first bank14, a display element failure caused by the defect portion3occurs only in a region defined by the dam structure50in the space20. According to at least one embodiment, a dam structure50(a pair of dam elements52) is formed on two second banks24, and accordingly a color mixture region produced in a region defined by the dam structure50coincides with a single subpixel region. In other words, occurrence of the display element failure caused by the defect portion3can be confined within a single subpixel in a space20in which the dam structure50is formed.

[Determination of Repair Target Spaces]

The following describes a method of determining a space20in which a dam structure50is to be formed (hereinafter, repair target space) among two adjacent spaces20that are each located between a first bank14having a defect portion3and an adjacent first bank14.

In the case where a dam structure50is formed in only one of two adjacent spaces20that are each located between a first bank14having a defect portion3and an adjacent first bank14, color mixture regions are formed inFIG. 12A. Specifically, in the space20in which no dam structure50is formed, the color mixture region spreads far along the first banks14in the Y direction. Meanwhile, in the space20in which the dam structure50is formed, the color mixture region spreads only within a region defined by the dam structure50. Thus, according to at least one embodiment, in consideration of change in light-emission color from the originally specified one with respect to one space20in which no dam structure50has been formed and an adjacent space20in which a dam structure50has been formed, a repair target space is determined, such that the one space20in which a color mixture region having a larger surface area is produced than in the adjacent space20, that is, the one space20in which no dam structure50has been formed, is smaller in terms of change in light-emission color from the originally specified color than the adjacent space20in which the dam structure50has been formed, compared with the case where the adjacent space20has no dam structure50.

When the display panel100is manufactured using a panel whose light-emitting layer has a color mixture region, the color mixture region emits light of a color differing from the originally specified color. Typically, when light-emitting materials of different light-emission colors are mixed, the light-emission color having longer wavelength becomes dominant. This is because it is regarded that a light-emitting material with a light-emission color having a longer wavelength has a smaller energy level (energy gap) relevant to light emission, and thus tends to emit light more easily.

In view of this, according to at least one embodiment, in the case where a dam structure50is formed in only one of two adjacent spaces20that are each located between a first bank14having a defect portion3and an adjacent first bank14, the one space20to which an ink of a light-emission color having a shorter wavelength is to be applied than the other space20is determined as a repair target space.

FIG. 13is a flow chart illustrating processing of determining a repair target space performed by the repair device200pertaining to at least one embodiment. Note that a storage unit232of the repair device200has stored beforehand therein coordinate positions in the X direction of first banks14and information indicating ink colors to be applied to spaces20.

When the processing starts, a coordinate position of a defect portion3in the X direction is firstly acquired (Step S21).

Next, with reference to the coordinate positions in the X direction of the first banks14and the information indicating the ink colors to be applied to the spaces20, which are stored in the storage unit232of the repair device200, two adjacent spaces20that are each located between a first bank14having the defect portion3and an adjacent first bank14are specified, and respective ink colors to be applied to the specified spaces20are further specified (Step S22).

In the case where the respective ink colors to be applied to the two adjacent spaces20, between which the first bank14having the defect portion is located, are red and green colors (Step S23: Yes), one of the spaces20to which the green ink, which has a shorter wavelength than the red ink, is to be applied is determined as a repair target space (Step S24).

In the case where the respective ink colors to be applied to the two adjacent spaces20, between which the first bank14having the defect portion is located, are green and blue colors (Step S25: Yes), one of the spaces20to which the blue ink, which has a shorter wavelength than the green ink, is to be applied is determined as the repair target space (Step S26).

In the case where the respective ink colors to be applied to the spaces20, between which the first bank14having the defect portion is located, are blue and red colors (Step S27: Yes), one of the spaces20to which the blue ink, which has a shorter wavelength than the red ink, is to be applied is determined as the repair target space (Step S28).

According to at least one embodiment, the repair target space is determined in this way.

The display panel100pertaining to at least one embodiment is described as above. However, the present disclosure is not limited to at least one embodiment above except the essential characteristic compositional elements thereof. For example, the present disclosure also includes an embodiment obtained through various types of modifications which could be conceived of by one skilled in the art to at least one embodiment above, an embodiment obtained through any combination of the compositional elements and the functions in at least one embodiment above without departing from the spirit of the present disclosure. The following describes modifications of the display panel100as examples of such embodiments.

According to at least one embodiment above, the dam elements52are formed on the second banks24. However, the forming position of the dam elements52is not limited to this.

FIG. 14AandFIG. 14Bare schematic perspective views illustrating forming position of dam elements52pertaining to the first modification.

FIG. 14Aillustrates a state where a foreign particle has adhered onto one first bank14aand has become a defect portion3.FIG. 14Billustrates a state where a dam structure50, which is composed of a pair of dam elements52disposed with the defect portion3therebetween in the Y direction, has been formed.

FIG. 15Ais a schematic plan view illustrating forming position of a dam structure50pertaining to the first modification.FIG. 15Bis a schematic plan view illustrating a state where the dam structure50has been formed pertaining to the first modification.

InFIG. 15A, when a defect portion3is detected on a first bank14a, respective coordinates positions indicating two end portions of the defect portion3in the Y direction are acquired. Further, values A1and A2are calculated by adding a tolerance value a0 to the respective coordinate values. The values A1and A2so calculated are set as candidate forming positions for the dam structure50. Then, in

FIG. 15A, in one of two adjacent spaces20partitioned by the first bank14ahaving the defect portion3, application points P1, P2, P3, and P4are set along each of (i) a dam forming line extending in the X direction through point A1and (ii) a dam forming line extending in the X direction through point A2. Points A1and A2are points located at a distance corresponding to the tolerance value a0 in the Y direction from the respective end portions of the defect portion3.

The dam structure50is formed in this way in a luminous region of a pixel partitioned by the second banks24. Owing to this structure, normal light-emission is expected outside a region defined by the dam structure50, thereby reducing a surface area where a display element failure occurs.

According to at least one embodiment above, the dam structure50, which is composed of a pair of dam elements52disposed with a defect portion3therebetween in the Y direction, is formed in a repair target space at a predetermined distance or less from the defect portion3. However, the shape of the dam structure50is not limited to this.

FIG. 16Ais a schematic perspective view illustrating the shape of a dam structure50pertaining to the second modification, andFIG. 16Bis a schematic plan view illustrating a state where ink layers have been formed after the dam structure50has been formed in a space20pertaining to the second modification.

The dam structure50pertaining to the present modification has the shape illustrated inFIG. 16B. Specifically, in plan view of the X-Y plane, the dam structure50extends between two points (point A1and point A2) between which a defect portion3is located in the Y direction, while detouring around the defect portion3. Also, the dam structure50comes in contact with a first bank14adjacent to a first bank14having the defect portion3at point A3located at some point along the path between point A1and point A2.

According to the second modification, the dam structure50can be formed by using a method similar to the method described in at least one embodiment above with reference toFIG. 11AthroughFIG. 11G. Specifically, in the second modification, the dam structure50can be formed by using a needle dispenser and applying the repair material to a plurality of application points set along a dam forming line that extends between point A1and point A2via point A3, one after another.

According to at least one embodiment above, the dam structure50, which is composed of a pair of dam elements52disposed with a defect portion3therebetween in the Y direction, is formed in a repair target space at a predetermined distance or less from the defect portion3. However, the shape of the dam structure50is not limited to this.

FIG. 17Ais a schematic perspective view illustrating the shape of a dam structure50pertaining to the fourth modification, andFIG. 17Bis a schematic plan view illustrating a state where ink layers have been formed after the dam structure50has been formed in a space20pertaining to the fourth modification.

The dam structure50pertaining to the present modification has the shape illustrated inFIG. 17B. Thus, the dam structure50pertaining to the present modification is similar to the dam structure50pertaining to the second modification in that in plan view of the X-Y plane, the dam structure50extends between two points (point A1and point A2) between which a defect portion3is located in the Y direction, while detouring around the defect portion3. However, the dam structure50pertaining to the present modification differs from the dam structure50pertaining to the second modification in that the dam structure50does not come in contact with a first bank14adjacent to a first bank14having the defect portion3. In other words, the dam structure50pertaining to the third modification is such that a maximum X-direction distance b between the dam structure50and the center of the defect portion3is set so as to be smaller than the width (X-direction width) of the space20.

The dam structure50can also be formed by using a method similar to the method described in at least one embodiment above with reference toFIG. 11AthroughFIG. 11G. Specifically, the dam structure50can be formed by using a needle dispenser and applying the repair material to a plurality of application points set along a dam forming line that extends between point A1and point A2, one after another.

At least one embodiment above describes bank repair methods and forms of banks while taking a top emission organic EL display panel as an example. However, the technology pertaining to the present disclosure is also applicable to a bottom emission organic EL display panel.

At least one embodiment above describes bank repair methods and forms of banks while taking an organic EL display panel as an example. However, display panels to which the technology pertaining to the present disclosure is applicable are not limited to organic EL display panels. The technology pertaining to the present disclosure is also applicable to display panels of any type including self-luminous layers that have been formed in banks having the line bank structure through the wet process. For example, the technology pertaining to the present disclosure is also applicable to display panels including self-luminous layers, which have been formed through the wet process in banks having the line bank structure by using a solvent in which electroluminescence quantum dots have been dispersed. Such display panels exhibit the similar effects.

The following further describes the structure of the present disclosure.

(1) A method pertaining to at least one aspect of the present disclosure is a method of manufacturing a self-luminous display panel. The method includes: preparing a substrate; forming banks above the substrate; detecting a bank having a defect portion among the banks; determining, with respect to the detected bank having the defect portion, only one of two adjacent spaces as a repair target space; forming a dam structure in the repair target space; and forming light-emitting layers. The banks are each elongated and each extend in a column direction, and are arranged in a row direction with spaces therebetween. The two adjacent spaces are each located between the detected bank and a bank adjacent to the detected bank in the row direction. The dam structure is located within a predetermined distance from the defect portion. The dam structure at least partially surrounds the defect portion, or is composed of a pair of dam elements disposed with the defect portion therebetween in the column direction. The light-emitting layers are formed by applying inks to the spaces between the banks. The inks contain self-luminous materials.

(2) According to at least one embodiment, the determining determines, as the repair target space, the one space in which a light-emitting layer emitting light at a shorter wavelength is to be formed than in the other space.

(3) According to at least one embodiment, in the forming of the light-emitting layers, an ink that is applied to a region defined by the dam structure in the repair target space flows into the other space via the defect portion.

(4) According to at least one embodiment, in the forming of the light-emitting layers, an ink that is applied to the other space flows into a region defined by the dam structure in the repair target space via the defect portion.

(5) A self-luminous display panel pertaining to at least one aspect of the present disclosure is a self-luminous display panel including: a substrate; banks disposed above the substrate; and light-emitting layers. The banks are each elongated and extend in a column direction, and are arranged in a row direction with spaces therebetween. The light-emitting layers contain self-luminous materials, and are formed by applying inks to the spaces between the banks. At least one of the banks has a defect portion. With respect to the bank having the defect portion, a dam structure is provided in only one of two adjacent spaces that are each located between the bank and a bank adjacent to the bank in the row direction. The dam structure is located within a predetermined distance from the defect portion. The dam structure at least partially surrounds the defect portion, or is composed of a pair of dam elements disposed with the defect portion therebetween in the column direction.

(6) According to at least one embodiment, the dam structure is provided in the one space in which a light-emitting layer emitting light at a shorter wavelength is formed than in the other space.

(7) According to at least one embodiment, the other space includes a self-luminous material that is contained in an ink applied to the one space.

(8) According to at least one embodiment, the one space includes a self-luminous material that is contained in an ink applied to the other space.

According to the method of manufacturing the self-luminous display panel pertaining to at least one embodiment, as described above, a dam structure is provided in one of two adjacent spaces that are each located between a bank having a defect portion and an adjacent bank. Owing to this structure, in formation of organic functional layers by applying inks of different light-emission colors to spaces between banks, a color mixture region, where inks of different light-emission colors mix with one another, does not spread beyond the dam structure in the one space in which the dam structure has been provided. Meanwhile, the spread of a color mixture region is not prevented in the other space in which no dam structure has been provided. Instead, only a limited amount of an ink flows into the other space from the one space. Furthermore, the ink which has flowed into the other space spreads along adjacent banks. This confines the change in light-emission color from the originally specified color in the color mixture region in the other space to a negligible degree. Thus, according to the self-luminous display panel pertaining at least one embodiment, a display element failure caused by a defect portion of a bank is confined within a range that is defined by a dam structure formed in one of two adjacent spaces with between the bank having the defect portion is located.

Supplements

At least one embodiment above show a preferred specific example of the present disclosure. The numerical values, the shapes, the materials, the structural elements, the arrangement and connection status of the structural elements, the processes, the order of the processes, and so on described in at least one embodiment above are just examples, and do not intend to limit the present disclosure. Also, processes among the structural elements in at least one embodiment above, which are not described in the independent claims representing the most generic concept of the present disclosure, are explained as arbitrary structural elements of a more preferred embodiment.

Furthermore, the order of performing the above processes is exemplification for specifically describing the present disclosure, and the processes may be performed in an order different from the above one. Moreover, part of the above processes may be performed simultaneously (in parallel) with other process.

Also, the structural elements shown in the figures in at least one embodiment above are not necessarily exactly scaled for easy understanding of the present disclosure. Furthermore, the present disclosure is not limited by the description of at least one embodiment above, and may be appropriately modified without departing from the scope of the present disclosure.

Moreover, at least part of the functions of at least one embodiment above may be combined with each other.

Furthermore, the present disclosure also includes embodiments obtained through various types of modifications that could be conceived of by one skilled in the art to at least one embodiment above.

Although the technology pertaining to the present disclosure has been fully described by way of examples with reference to the accompanying drawings, various changes and modifications will be apparent to those skilled in the art. Therefore, unless such changes and modifications depart from the scope of the present disclosure, they should be construed as being included therein.