Display device and method for manufacturing same

Abstract

An organic EL display device (1) comprises: a flattening film (50) provided on a circuit configuration layer (20); a plurality of organic EL elements (61) provided on the flattening film; and a bank (64) extending between the organic EL elements adjacent to each other. The organic EL elements have pixel electrodes (62) individually provided on the flattening film. A recess portion (58) recessed toward the circuit configuration layer side is formed between the pixel electrodes adjacent to each other on the surface of the flattening film. The bank is made of a colored resin having visible light absorbency, and is provided so as to fill the inside of the recess portion.

Description

Display device and method for manufacturing the same

[0004]

[0001] The present disclosure relates to a display device and a method for manufacturing the same.

[0002] In recent years, as a display device, an organic electroluminescence (EL) display device using an organic EL element has been put into practical use. A plurality of organic EL elements are provided in a predetermined arrangement to form a display area for displaying an image. Adjacent organic EL elements are partitioned by a bank. The bank is made of a colorless or colored resin. Functional layers such as a hole injection layer forming the organic EL layer included in the organic EL element are formed by applying an organic material within a region surrounded by the bank (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2009-07074

[0004] The organic EL display device can adopt a configuration in which a plurality of organic EL elements are provided via a planarization film on a circuit configuration layer including circuit elements such as TFTs (Thin Film Transistors) and wirings. In such a configuration, when the bank is made of a colored resin, it has light absorptivity and functions as a shielding portion that shields the lower layer portion between the pixel electrodes included in the organic EL element. The height of such a bank from the surface of the pixel electrode is relatively high in order to ensure light shielding properties. Therefore, when forming a functional layer forming the organic EL layer by a coating method such as an inkjet method, the applied organic material tends to be relatively thick at a portion along the periphery of the bank, and the thickness of the functional layer becomes non-uniform. Then, there is a possibility that uneven light emission occurs in the organic EL element.

[0005] Therefore, it is conceivable to suppress the organic material of the functional layer forming the organic EL layer from becoming thick at a portion along the periphery of the bank during its coating by lowering the height of the bank from the surface of the pixel electrode. However, when the bank is made thin, the light shielding property of the bank is impaired. For this reason, the bank cannot suitably shield the lower layer portion between the pixel electrodes, and light incident on the screen from the outside of the organic EL display device passes through the bank, is reflected by the electrodes and wirings included in the circuit configuration layer, and passes through the bank again and is visually recognized by the user. Such reflection of external light causes a decrease in display quality.

[0006] The purpose of this disclosure is to obtain sufficient light shielding properties in the bank and to reduce the risk of non-emitting areas occurring in the EL layer.

[0007] This disclosure relates to a display device. The display device according to this disclosure comprises a circuit configuration layer including circuit elements and wiring, a planarization film provided on the circuit configuration layer, a plurality of light-emitting elements provided on the planarization film, and a bank extending between adjacent light-emitting elements. Each of the plurality of light-emitting elements has a pixel electrode individually provided on the planarization film, an EL layer provided on the pixel electrode, and a common electrode provided so as to overlap the pixel electrode via the EL layer. A recess is formed on the surface of the planarization film between adjacent pixel electrodes, recessing toward the circuit configuration layer. The bank is made of a colored resin having visible light absorbing properties, is provided to fill the recess, and shields the lower layer between adjacent pixel electrodes.

[0008] This disclosure relates to a method for manufacturing a display device. The method for manufacturing a display device according to this disclosure includes a circuit configuration layer formation step of forming the circuit configuration layer on a substrate; a planarization film formation step of forming the planarization film on the circuit configuration layer; a pixel electrode formation step of forming the pixel electrodes on the planarization film; a bank formation step of forming the bank between adjacent pixel electrodes on the surface of the planarization film; an EL layer formation step of forming the EL layer so as to cover the bank; and a common electrode formation step of forming the common electrode so as to overlap the pixel electrodes via the EL layer. In the planarization film formation step, the planarization film is patterned to form the recesses. In the bank formation step, a colored resin having visible light absorption properties is applied to fill the recesses, and then the applied resin film is patterned to form the bank. In the EL layer formation step, at least a portion of the EL layer is formed by a coating method.

[0009] According to the technology disclosed herein, sufficient light shielding can be obtained in the bank, and the risk of non-emitting areas occurring in the EL layer can be reduced.

[0010] Figure 1 is a plan view illustrating the schematic configuration of an organic EL display device according to an embodiment. Figure 2 is a cross-sectional view of the organic EL display device along line II-II in Figure 1. Figure 3 is a plan view illustrating pixels and various wirings constituting the display area of ​​the organic EL display device. Figure 4 is a cross-sectional view of the organic EL display device along line IV-IV in Figure 3. Figure 5A is a cross-sectional view illustrating a part of the manufacturing process of the organic EL display device according to an embodiment. Figure 5B is a cross-sectional view illustrating a part of the manufacturing process of the organic EL display device according to an embodiment. Figure 5C is a cross-sectional view illustrating a part of the manufacturing process of the organic EL display device according to an embodiment. Figure 6A is a cross-sectional view illustrating a key part in the manufacturing process of the organic EL display device according to an embodiment. Figure 6B is a cross-sectional view illustrating a key part in the manufacturing process of an organic EL display device according to a comparative example. Figure 7 is a cross-sectional view corresponding to Figure 4 of an organic EL display device according to a first modified example. Figure 8A is a cross-sectional view illustrating a part of the manufacturing process of the organic EL display device according to a first modified example. Figure 8B is a cross-sectional view illustrating a part of the manufacturing process of the organic EL display device according to a first modified example. Figure 8C is a cross-sectional view illustrating a part of the manufacturing process of the organic EL display device according to a first modified example. Figure 9A is a cross-sectional view illustrating a part of the manufacturing process of an organic EL display device according to the second modified example. Figure 9B is a cross-sectional view illustrating a part of the manufacturing process of an organic EL display device according to the second modified example. Figure 10 is a cross-sectional view corresponding to Figure 4 of an organic EL display device according to the third modified example. Figure 11A is a cross-sectional view illustrating a part of the manufacturing process of an organic EL display device according to the third modified example. Figure 11B is a cross-sectional view illustrating a part of the manufacturing process of an organic EL display device according to the third modified example. Figure 11C is a cross-sectional view illustrating a part of the manufacturing process of an organic EL display device according to the third modified example. Figure 12 is a cross-sectional view corresponding to Figure 4 of an organic EL display device according to the fourth modified example. Figure 13A is a cross-sectional view illustrating a part of the manufacturing process of an organic EL display device according to the fourth modified example. Figure 13B is a cross-sectional view illustrating a part of the manufacturing process of an organic EL display device according to the fourth modified example. Figure 13C is a cross-sectional view illustrating a part of the manufacturing process of an organic EL display device according to the fourth modified example. Figure 14A is a cross-sectional view illustrating a part of another manufacturing process of an organic EL display device according to the fifth modified example. Figure 14B is a cross-sectional view illustrating a part of another manufacturing process for an organic EL display device according to the fifth modified example.

[0011] Hereinafter, exemplary embodiments will be described in detail with reference to the drawings. In the following embodiments, an organic EL display device will be used as an example of the display device according to the Disclosure. The drawings are intended to conceptually illustrate the technology of the Disclosure. Therefore, in order to facilitate understanding of the technology of the Disclosure, dimensions, ratios, or numbers may be exaggerated or simplified in the drawings.

[0012] In the following embodiments, "first direction" means the horizontal direction of the screen in a predetermined orientation of the display device. "Second direction" means the direction orthogonal to the first direction and means the vertical direction of the screen in a predetermined orientation of the display device. A row of subpixels means an arrangement of subpixels forming a column in the first direction. A column of subpixels means an arrangement of subpixels forming a column in the second direction.

[0013] Furthermore, in the following embodiments, the statement that another film, layer, element, or other component is provided or formed on top of a certain film, layer, element, or other component does not mean only that the other component exists directly above the other component, but also includes cases where other films, layers, elements, or other components are interposed between the two components.

[0014] Furthermore, in the following embodiments, any description of a component being connected to another component means an electrically connected connection unless otherwise specified. Such description means not only a direct connection but also an indirect connection via other components, without departing from the spirit of the art of this disclosure. Such description also includes cases where one component is integrated with another component, that is, where a part of one component constitutes another component.

[0015] Furthermore, in the following embodiments, a statement that one component is a lower layer of another component means that the component is deposited in a process earlier than the other component, or is formed from a film deposited in an earlier process. A statement that one component is an upper layer of another component means that the component is deposited in a process later than the other component, or is formed from a film deposited in a later process.

[0016] 《Embodiment》 The organic EL display device 1 of this embodiment is used as a display for mobile devices such as smartphones and tablet terminals. The organic EL display device 1 may also be used as a display for various other devices such as personal panel computers (PCs) and television equipment.

[0017] -Configuration of the Organic EL Display Device- The Organic EL display device 1 is a display device that uses an organic EL element 61, also called an OLED (Organic Light Emitting Diode). The Organic EL display device 1 employs an active matrix drive method and is configured to display full color. As shown in Figure 1, the Organic EL display device 1 has a display area DA and a bezel area FA.

[0018] The display area DA is the area where the image is displayed and constitutes the screen. The display area DA is provided in a rectangular shape, for example. The display area DA may be a substantially rectangular shape such as a shape in which at least one side is arc-shaped, a shape in which at least one corner is arc-shaped, or a shape in which at least one side has a notch, or it may be any other arbitrary shape.

[0019] The frame area FA is the area that constitutes the non-display portion other than the screen. The frame area FA is provided around the display area DA, for example, in the shape of a rectangular frame. The frame area FA may be a frame shape other than a rectangle. The frame area FA includes a terminal portion TP and a bend portion BP. The terminal portion TP and the bend portion BP are provided in the portion that constitutes the same side of the frame area FA.

[0020] The terminal section TP is the part for connecting to an external circuit. The terminal section TP is provided at the end of the frame area FA. Specifically, the terminal section TP is located near the outer edge of the part that constitutes one side of the frame area FA and extends along that side. Multiple terminals (not shown) are provided on the terminal section TP in a predetermined pattern. A wiring board CB, such as an FPC (Flexible Printed Circuit), is connected to the terminal section TP.

[0021] The bent portion BP is provided between the terminal portion TP and the display area DA in the frame area FA, extending in the first direction Dx. The bent portion BP is the part that is bent around an axis extending in the first direction Dx. The bent portion BP extends horizontally across the entire frame area FA in the first direction Dx. In the bent portion BP, the inorganic insulating film contained in the circuit component layer 20 is removed, resulting in higher flexibility than other parts.

[0022] The bezel area FA of the organic EL display device 1 is bent at the bending portion BP to form a U-shape, for example, by about 180° (shown by the dashed line in Figure 2). As a result, the terminal portion TP and the wiring board CB are located on the back side of the organic EL display device 1. Display control circuits, such as source drivers, are mounted on the wiring board CB as IC (Integrated Circuit) chips or connected via other circuit boards.

[0023] A drive circuit Dc is provided in the frame region FA. The drive circuit Dc is positioned in the portion of the frame region FA that constitutes the side adjacent to the side where the terminal portion TP is provided (each side on the left and right in Figure 1). The drive circuit Dc is formed monolithically as part of the circuit configuration layer 20. The drive circuit Dc includes a gate driver and an emission driver.

[0024] The frame area FA is further provided with numerous wirings of various types, such as power lines 30 and lead lines 36. The power lines 30 are wirings for applying current to the organic EL element 61 by the pixel circuit Pc. The power lines 30 include a first power trunk line 32 (shown with upward-sloping diagonal hatching in Figure 1 for convenience) and a second power trunk line 34 (shown with upward-sloping diagonal hatching in Figure 1 for convenience).

[0025] The first power trunk line 32 is provided so as to extend in a first direction Dx between the display area DA and the bent portion BP. On both sides of the first power trunk line 32 in the first direction Dx, portions are provided that extend to the terminal portion TP via the bent portion BP. A high-level power supply voltage (ELVDD) is supplied to the first power trunk line 32 at the terminal portion TP via the wiring board CB.

[0026] The second power line 34 is provided in a roughly C-shape so as to surround the first power line 32 and the display area DA. Both ends of the second power line 34 extend to the terminal section TP via the bent section BP so as to run parallel to the first power line 32. A low-level power supply voltage (ELVSS) is supplied to the second power line 34 at the terminal section TP via the wiring board CB.

[0027] Multiple lead wires 36 are provided between the display area DA and the terminal section TP. The lead wires 36 are drawn out from the display area DA through the bending section BP to the terminal section TP. The lead wires 36 are connected to the source line 28 on the display area DA side. The lead wires 36 are part of the source line 28. The end of each lead wire 36 located at the terminal section TP and the respective ends of the first power trunk line 32 and the second power trunk line 34 each form a terminal at the terminal section TP.

[0028] <Display Area> As shown in Figure 3, the display area DA is composed of multiple pixels PX. The multiple pixels PX are arranged in a matrix. Each pixel PX is composed of three subpixels SP. The three subpixels SP are a red subpixel SPr that emits red light, a green subpixel SPg that emits green light, and a blue subpixel SPb that emits blue light. These red subpixels SPr, green subpixels SPg, and blue subpixels SPb are arranged, for example, in a stripe pattern.

[0029] The display area DA is provided with a plurality of organic EL elements 61 and a plurality of pixel circuits Pc. The organic EL element 61 is an example of a light-emitting element. The plurality of organic EL elements 61 are provided corresponding to a plurality of sub-pixels SP. Each organic EL element 61 constitutes a sub-pixel SP. The pixel circuit Pc is a circuit for each sub-pixel and controls the light emission of the organic EL element 61 that makes up the corresponding sub-pixel SP.

[0030] The display area DA is further provided with various wirings related to the operation of the pixel circuit Pc. The wiring provided in the display area DA includes a plurality of gate lines 22, a plurality of light emission control lines 24, a plurality of power supply branch lines 26, and a plurality of source lines 28. The gate lines 22, light emission control lines 24, power supply branch lines 26, and source lines 28 are each connected to the pixel circuit Pc.

[0031] Each of the multiple gate lines 22 is a wiring that transmits a gate signal to the pixel circuit Pc. The multiple gate lines 22 are spaced apart from each other in the second direction Dy and extend parallel to each other in the first direction Dx. A gate line 22 is provided for each row of sub-pixel SP. Each gate line 22 is led out to the frame area FA and connected to the gate driver of the drive circuit Dc.

[0032] Each of the multiple light emission control lines 24 is a wire that transmits an emission signal to the pixel circuit Pc. The multiple light emission control lines 24 are spaced apart from each other in the second direction Dy and extend parallel to each other in the first direction Dx. A light emission control line 24 is provided for each row of sub-pixel SP. Each light emission control line 24 is led out to the frame area FA and connected to the emission driver of the drive circuit Dc.

[0033] Each of the multiple power supply branch lines 26 is part of the power supply line 30 and is wiring that supplies a predetermined high-level power supply voltage (ELVDD) to the pixel circuit Pc. The multiple power supply branch lines 26 are arranged spaced apart from each other in the first direction Dx and extend parallel to each other in the second direction Dy. A power supply branch line 26 is provided for each row of sub-pixels SP. Each power supply branch line 26 is led out to the frame area FA on the terminal section TP side and connected to the first power supply trunk line 32.

[0034] Each of the multiple source lines 28 is a wiring that transmits a source signal to the pixel circuit Pc. The multiple source lines 28 are arranged spaced apart from each other in the first direction Dx and extend parallel to each other in the second direction Dy. A source line 28 is provided for each row of sub-pixels SP. Each source line 28 is led out as a lead line 36 to the terminal section TP and connected to the source driver via the wiring board CB.

[0035] The pixel circuit Pc operates based on signals and voltages supplied by gate line 22, light emission control line 24, power supply branch line 26, and source line 28, and supplies drive current to the corresponding organic EL element 61. The pixel circuit Pc is composed of a plurality of thin film transistors (hereinafter referred to as TFTs) 40 and a capacitor 42.

[0036] <Laminated structure of organic EL display device> As shown in Figure 2, the organic EL display device 1 comprises a substrate layer 10, a circuit configuration layer 20, a planarization film 50, a light-emitting element layer 60, and a sealing film 70. The substrate layer 10 and the circuit configuration layer 20 constitute a circuit board called a backplane.

[0037] <Substrate Layer> The substrate layer 10 is the base layer of the organic EL display device 1. The substrate layer 10 is an example of a substrate. The substrate layer 10 is flexible. The substrate layer 10 is formed from an organic resin material such as polyimide resin, polyamide resin, or epoxy resin. A protective film 12 is attached to the back surface of the substrate layer 10.

[0038] <Circuit Configuration Layer> As shown in Figure 4, the circuit configuration layer 20 is provided on the substrate layer 10. The circuit configuration layer 20 includes a drive circuit Dc, various wirings (not shown in Figure 4) as described above, and a plurality of TFTs 40 and capacitors 42 that form a pixel circuit Pc. The TFTs 40 and capacitors 42 are examples of circuit elements.

[0039] A base coat film (not shown) is provided on the surface of the substrate layer 10. The base coat film is formed from an inorganic insulating material such as silicon oxide, silicon nitride, or silicon oxynitride. The TFT 40 and capacitor 42 are provided on the base coat film. A base coat film is not required on the surface of the substrate layer 10.

[0040] Multiple TFTs 40 are provided for each pixel circuit Pc. The TFTs 40 are configured, for example, as a top-gate type. As semiconductors, oxide semiconductors such as In-Ga-Zn-O semiconductors or low-temperature polycrystalline silicon (LTPS) are used for the TFTs 40. Although not shown in the figure, the TFTs 40 have a gate electrode, a first terminal electrode, and a second terminal electrode.

[0041] At least one capacitor 42 is provided for each pixel circuit Pc. Although not shown, the capacitor 42 has a first capacitance electrode and a second capacitance electrode. The first capacitance electrode and the second capacitance electrode overlap each other via an insulating film included in the circuit configuration layer 20. The first capacitance electrode and the second capacitance electrode may each be composed of other electrodes or parts of wiring.

[0042] The various types of wiring and electrodes described above are made of metallic materials such as aluminum (Al), tungsten (W), molybdenum (Mo), tantalum (Ta), chromium (Cr), titanium (Ti), and copper (Cu). These various types of wiring and electrodes may be made of a single layer film made of the metallic material, or of a multilayer film made of the metallic material. The same applies to the connecting wires 54 described later.

[0043] <Planarization Film> The planarization film 50 is provided on the circuit configuration layer 20 so as to cover the drive circuit Dc, various wirings, multiple TFTs 40, and multiple capacitors 42. The planarization film 50 is provided over the entire display area DA and extends to the frame area FA. The upper surface of the circuit configuration layer 20 is planarized by the planarization film 50. The planarization film 50 in this embodiment is made up of a laminated film. Specifically, the planarization film 50 is made up of a first planarization film 52 and a second planarization film 56 laminated together.

[0044] The first planarization film 52 is provided directly above the circuit configuration layer 20. A first contact hole Ha is formed in the first planarization film 52. The first contact hole Ha is provided for each organic EL element 61. The first contact hole Ha penetrates through a wiring connected to the first terminal electrode or the second terminal electrode forming a predetermined TFT 40, or either one of them.

[0045] A plurality of connection lines 54 are provided on the first planarization film 52. Each of the plurality of connection lines 54 is a wiring that connects a corresponding pixel circuit Pc (strictly speaking, a predetermined TFT 40 constituting the pixel circuit Pc) and the organic EL element 61. The connection line 54 is connected to a wiring connected to the first terminal electrode or the second terminal electrode forming a predetermined TFT 40, or either one of them, through the first contact hole Ha.

[0046] The second planarization film 56 is provided on the first planarization film 52 so as to cover the plurality of connection lines 54. A second contact hole Hb is formed in the second planarization film 56. The second contact hole Hb is provided for each organic EL element 61. The second contact hole Hb opens at a location corresponding to the first contact hole Ha or its periphery in a plan view and penetrates through the connection line 54.

[0047] A recess 58 is formed on the surface of the planarization film 50. The recess 58 is a groove-shaped portion recessed toward the circuit configuration layer 20 side and is located between adjacent pixel electrodes 62. The depth of the recess 58 is, for example, 1.0 μm or more and 3.0 μm or less. The recess 58 is formed in a lattice shape that continuously extends so as to surround the periphery of each pixel electrode 62 in a plan view.

[0048] The recess 58 of the present embodiment is provided without penetrating the planarization film 50. The recess 58 is formed by the second planarization film 56. Specifically, the second planarization film 56 is divided for each region corresponding to the pixel electrode 62. The recess 58 is formed between adjacent second planarization films 56 and exposes the first planarization film 52 at the bottom. The depth of the recess 58 corresponds to the thickness of the second planarization film 56.

[0049] <Light-emitting element layer> The light-emitting element layer 60 is provided on the planarized film 50. The light-emitting element layer 60 includes a plurality of organic EL elements 61 and a bank 64. The organic EL element 61 is an example of a light-emitting element. Each organic EL element 61 is connected to a separate pixel circuit Pc. The light emission of each organic EL element 61 is controlled by the operation of the corresponding pixel circuit Pc.

[0050] Each of the multiple organic EL elements 61 is configured as a top-emission type. The light emitted from each organic EL element 61 is extracted to the sealing film 70 side. Each organic EL element 61 has a pixel electrode 62, an organic EL layer 66, and a common electrode 68. The organic EL layer 66 is an example of an electroluminescent layer. Each organic EL element 61 has an individually separated light-emitting layer 66b as part of the organic EL layer 66.

[0051] Multiple organic EL elements 61 are composed of multiple types of organic EL elements 61 that emit light in colors different from each other. The multiple types of organic EL elements 61 include a red light-emitting element 61r, a green light-emitting element 61g, and a blue light-emitting element 61b. The red light-emitting element 61r includes a light-emitting layer 66b that emits red light. The green light-emitting element 61g includes a light-emitting layer 66b that emits green light. The blue light-emitting element 61b includes a light-emitting layer 66b that emits blue light.

[0052] The pixel electrodes 62 are individually provided on the planarization film 50. The pixel electrodes 62 are provided in a predetermined arrangement to correspond to a plurality of sub-pixels SP. Each pixel electrode 62 is connected to a connecting line 54 via a second contact hole Hb. The pixel electrodes 62 have the property of reflecting light and function as anodes. It is preferable to use a conductive material with a large work function for the pixel electrodes 62.

[0053] The material of the pixel electrode 62 may be a metal such as silver (Ag) or nickel (Ni), or it may be a metal compound or alloy. The material of the pixel electrode 62 may also be a conductive oxide such as indium tin oxide (ITO) or indium zinc oxide (IZO). The pixel electrode 62 may be composed of a single layer film or a multilayer film.

[0054] The bank 64 is provided on the planarization film 50 to partition a plurality of pixel electrodes 62. The bank 64 is provided to fill the recesses 58 of the planarization film 50 and is formed in a grid pattern as a whole. The bank 64 extends between adjacent pixel electrodes 62 and around the display area DA. The bank 64 shields the lower layer between adjacent pixel electrodes 62. The bank 64 has openings that expose each pixel electrode 62.

[0055] The bank 64 is provided so as to cover the outer peripheral edge of each pixel electrode 62. The bank 64 is provided higher above the surface of the pixel electrode 62. From the viewpoint of preventing the thickness of the lower functional layer 66a from increasing along the periphery of the bank 64, it is preferable that the height of the bank 64 from the surface of the pixel electrode 62 be low. In this embodiment, the height of the bank 64 from the surface of the pixel electrode 62 is 0.2 μm or more and 1.0 μm or less.

[0056] Bank 64 is made of a colored resin that absorbs visible light. The colored resin making up Bank 64 is a black photosensitive resin. Photosensitive resins have the property of undergoing a chemical change and solidifying when exposed to light. This property allows for precise pattern formation of the photosensitive resin, which is advantageous in the manufacturing process of the organic EL display device 1. The photosensitive resin making up Bank 64 is a positive-type photosensitive resin, and although black, it also has light transmittance.

[0057] The optical density of bank 64 is preferably high from the viewpoint of shielding elements such as wiring contained in the circuit component layer 20. However, when forming bank 64, it is necessary to allow light to penetrate to the interior of the photosensitive resin. For this reason, there is a limit to how high the optical density of bank 64 can be. The optical density of bank 64 at visible light wavelengths per 1 μm thickness is 0.5 or more and 1.5 or less. The "optical density" referred to here is also called the OD (Optical Density) value. The optical density of bank 64 can be measured using a commercially available spectrophotometer (for example, Hitachi U-4100 or Otsuka Electronics MCPD series).

[0058] The organic EL layer 66 is provided so as to overlap the individual pixel electrodes 62 within the opening of the bank 64. The organic EL layer 66 has a lower functional layer 66a, an emissive layer 66b, and an upper functional layer 66c, which are provided in order on the pixel electrodes 62. The lower functional layer 66a is a laminate of either a hole injection layer and a hole transport layer or both thereof, or a hole injection and transport layer. The upper functional layer 66c is a laminate of either an electron injection layer and an electron transport layer or both thereof, or an electron injection and transport layer.

[0059] The lower functional layer 66a is provided in common as a continuous unit for multiple sub-pixels SP so as to cover the bank 64 and overlap the pixel electrodes 62 inside each opening of the bank 64. The light-emitting layer 66b is provided individually for each sub-pixel SP so as to overlap the pixel electrodes 62 via the lower functional layer 66a. The upper functional layer 66c is provided in common as a continuous unit for multiple sub-pixels SP so as to cover the multiple light-emitting layers 66b. The lower functional layer 66a, the light-emitting layer 66b, and the upper functional layer 66c are made of known compounds suitable for their respective functions.

[0060] The common electrode 68 is provided as a continuous unit for multiple sub-pixels SP. The common electrode 68 is arranged on the organic EL layer 66, covering the bank 64, and is provided so as to overlap each pixel electrode 62 via the organic EL layer 66. The common electrode 68 has the property of transmitting light and functions as a cathode. It is preferable to use a conductive material with a small work function for the common electrode 68.

[0061] The material of the common electrode 68 may be a metal such as magnesium (Mg) or aluminum (Al), or it may be an alloy or metal compound such as magnesium-silver alloy (MgAg). The material of the common electrode 68 may also be a conductive oxide such as indium tin oxide (ITO) or indium zinc oxide (IZO). The common electrode 68 may be composed of a single layer film or a multilayer film.

[0062] <Sealing Film> The sealing film 70 is provided on the light-emitting element layer 60. The sealing film 70 covers and seals the plurality of organic EL elements 61, protecting each organic EL element 61 (especially the organic EL layer 66) from moisture, oxygen, and the like. The sealing film 70 is provided over the entire display area DA and extends to the frame area FA. The sealing film 70 has a first inorganic layer 72, an organic layer 74, and a second inorganic layer 76.

[0063] The first inorganic layer 72 is provided so as to cover the common electrode 68. The organic layer 74 is provided on the first inorganic layer 72. The second inorganic layer 76 is provided so as to cover the organic layer 74. The first inorganic layer 72 and the second inorganic layer 76 overlap each other in the frame region FA. The organic layer 74 is enclosed by the first inorganic layer 72 and the second inorganic layer 76.

[0064] The first inorganic layer 72 and the second inorganic layer 76 are each made of an inorganic insulating material such as silicon oxide, silicon nitride, or silicon oxynitride. The organic layer 74 is made of an organic resin material such as acrylic resin, epoxy resin, silicone resin, polyurea resin, parylene resin, polyimide resin, or polyamide resin.

[0065] -Method for manufacturing an organic EL display device- The method for manufacturing the organic EL display device 1 includes a substrate layer formation step, a circuit configuration layer formation step, a planarization film formation step, a pixel electrode formation step, a bank formation step, an organic EL layer formation step, a common electrode formation step, and a sealing film formation step. The organic EL layer formation step corresponds to the electroluminescence layer formation step.

[0066] <Substrate Layer Formation Process> To manufacture the organic EL display device 1, first, a substrate layer formation process is performed. In the substrate layer formation process, an organic resin material is applied to the surface of the glass substrate 100 and baked. In this way, a substrate layer 10 is formed on the surface of the glass substrate 100.

[0067] <Circuit Layer Formation Process> Next, the circuit layer formation process is performed. In the circuit layer formation process, as shown in the upper diagram of Figure 5A, a circuit layer 20 is formed on the substrate layer 10. Specifically, a base coat film is deposited on the surface of the substrate layer 10, for example by plasma CVD (Chemical Vapor Deposition). Then, on the substrate on which the base coat film has been formed, various wirings, TFTs 40 and capacitors 42 are fabricated using known film deposition methods such as plasma CVD and sputtering, and known patterning techniques such as photolithography.

[0068] <Planarization Film Formation Process> Next, the planarization film formation process is performed. In the planarization film formation process, a planarization film 50 is formed on the circuit configuration layer 20. In this embodiment, a first planarization film 52, connecting lines 54, and a second planarization film 56 are formed in order on the substrate on which the circuit configuration layer 20 is formed.

[0069] Specifically, a photosensitive resin is applied to a substrate on which the circuit configuration layer 20 is formed by a known coating method such as spin coating or slit coating. Furthermore, the photosensitive resin coating film is pre-baked, exposed, developed, and post-baked, and the coating film is patterned to form a first planarized film 52 having a first contact hole Ha, as shown in the intermediate view of Figure 5A.

[0070] Next, a metal film made of molybdenum (Mo), titanium (Ti), aluminum (Al), etc., is deposited on the substrate on which the first planarization film 52 is formed, for example by sputtering. Furthermore, the metal film is patterned by photolithography to form connecting lines 54 on the first planarization film 52.

[0071] Subsequently, a photosensitive resin is applied to the substrate on which the connecting lines 54 are formed using a known coating method. Furthermore, the photosensitive resin coating film is pre-baked, exposed, developed, and post-baked, and the coating film is patterned to form a second planarization film 56 having a second contact hole Hb, as shown in the lower diagram of Figure 5A. At this time, the second planarization film 56 is patterned to form recesses 58. In this embodiment, the second planarization film 56 is formed on the first planarization film 52, divided into regions for forming the pixel electrodes 62. This forms recesses 58 in the planarization film 50.

[0072] <Pixel Electrode Formation Process> Next, the pixel electrode formation process is performed. In the pixel electrode formation process, as shown in the upper diagram of Figure 5B, pixel electrodes 62 are formed on the planarization film 50. Specifically, on the substrate on which the planarization film 50 is formed, for example, an indium tin oxide film (ITO film), a silver alloy film (Ag alloy film), and an indium tin oxide film (ITO film) are sequentially deposited by sputtering. In this way, a conductive film is formed on the second planarization film 56. Subsequently, the conductive film is patterned by photolithography to form the pixel electrode 62.

[0073] <Bank Formation Process> Next, the bank formation process is performed. In the bank formation process, as shown in the lower diagram of Figure 5B, banks 64 are formed between adjacent pixel electrodes 62 on the surface of the planarization film 50. Specifically, a colored photosensitive resin that absorbs visible light is applied to the substrate on which the pixel electrodes 62 are formed, using a known coating method, so as to fill the recesses 58. In this example, a positive-type photosensitive resin is used as the photosensitive resin. Furthermore, the coated film of the photosensitive resin is pre-baked, exposed, developed, and post-baked, and the coated film is patterned to form banks 64 on the planarization film 50.

[0074] <Organic EL Layer Formation Process> Next, the organic EL layer formation process is performed. In the organic EL layer formation process, as shown in the upper diagram of Figure 5C, an organic EL layer 66 is formed so as to cover the pixel electrode 62 and the bank 64. In this embodiment, a lower functional layer 66a, an emissive layer 66b, and an upper functional layer 66c are formed in order on the substrate on which the bank 64 is formed.

[0075] Specifically, an organic material, which is a solution containing a compound suitable for hole injection or transport, is applied to the substrate on which the bank 64 is formed, using a known coating method. Subsequently, the coated film of the organic material is baked to evaporate the solvent. In this way, a common lower functional layer 66a is formed so as to spread over the entire portion of the display area DA on the substrate.

[0076] Furthermore, an organic material, which is a solution containing a compound suitable for light emission, is applied to the substrate on which the lower functional layer 66a is formed, for example by an inkjet method. At this time, the organic material to be applied is applied to each pixel electrode 62 within the opening of the bank 64 according to the light emission color of the organic EL element 61. Subsequently, the applied film of the organic material is baked to evaporate the solvent. In this way, individual light-emitting layers 66b are formed in the region corresponding to each pixel electrode 62. These light-emitting layers 66b may also be formed by a lift-off process.

[0077] Then, an organic material, which is a solution containing a compound suitable for electron injection or transport function, is applied to the substrate on which the light-emitting layer 66b is formed, using a known coating method. Subsequently, the coated film of the organic material is baked to evaporate the solvent. In this way, a common upper functional layer 66c is formed so as to cover each light-emitting layer 66b and spread over the entire portion that forms the display area DA on the substrate.

[0078] <Common Electrode Formation Process> Next, the common electrode formation process is performed. In the common electrode formation process, as shown in the lower diagram of Figure 5C, a common electrode 68 is formed so as to overlap each pixel electrode 62 via the organic EL layer 66. Specifically, a conductive film such as an indium tin oxide film (ITO film), an indium zinc oxide film (IZO film), or a magnesium silver alloy film (MgAg film) is deposited on the substrate on which the organic EL layer 66 is formed, for example by vacuum deposition. As a result, the common electrode 68 is formed so as to extend over the entire portion of the display area DA and the frame area FA on the substrate.

[0079] <Sealing Film Formation Process> Next, the sealing film formation process is performed. In the sealing film formation process, a sealing film 70 is formed so as to cover the entire common electrode 68. Specifically, a first inorganic layer 72 is formed on the substrate on which the common electrode 68 is formed by plasma CVD. Subsequently, an organic resin material is applied to the substrate on which the first inorganic layer 72 is formed, and the applied film of the organic resin material is cured to form an organic layer 74. Then, a second inorganic layer 76 is formed on the substrate on which the organic layer 74 is formed by plasma CVD.

[0080] <Other processes> After that, the glass substrate 100 is peeled off the substrate layer 10 by irradiating the back surface of the substrate layer 10 with laser light from the glass substrate 100 side. Next, a protective film 12 is attached to the back surface of the substrate layer 10. A polarizing plate and cover panel are also attached to the surface of the sealing film 70. Furthermore, a wiring board CB is connected to the terminal section TP provided in the frame area FA, and a display control circuit such as a source driver is mounted.

[0081] In this manner, the organic EL display device 1 can be manufactured.

[0082] -Features of the Embodiment- In the organic EL display device 1 of this embodiment, recesses 58 are formed between adjacent pixel electrodes 62 on the surface of the planarization film 50. The bank 64 extending between adjacent organic EL elements 61 is provided so as to fill the recesses 58. This ensures the thickness of the bank 64. Therefore, even if the height of the bank 64 from the surface of the pixel electrodes 62 is reduced, sufficient light shielding can be obtained for the bank 64. As a result, light incident from outside the organic EL display device 1 can be blocked by the bank 64, and the reflection of ambient light incident on the screen of the organic EL display device 1 can be suppressed.

[0083] As shown in Figure 6B, unlike conventional organic EL displays, if the recess 58 is not formed in the planarization film 50 and the bank 64 is formed relatively high above the surface of the pixel electrode 62, when the lower functional layer 66a is formed by a known coating method, the coated organic material 101 tends to become relatively thicker in the portion along the periphery of the bank 64, which may cause uneven emission in the organic EL element 61.

[0084] In contrast, according to the organic EL display device 1 of this embodiment, as shown in Figure 6A, by lowering the height of the pixel electrode 62 from the surface in the bank 64, it is possible to suppress the relatively thickening of the coated organic material 101 in the portion along the periphery of the bank 64 when forming the lower functional layer 66a that constitutes the organic EL layer 66 by coating. This makes it less likely for uneven light emission to occur in the organic EL element 61.

[0085] In this embodiment of the organic EL display device 1, the recess 58 does not penetrate the planarization film 50. Therefore, the circuit configuration layer 20 can be covered and protected by the planarization film 50. This makes it possible to suppress damage to the circuit configuration layer 20 caused by the process of forming the pixel electrodes 62 during the manufacturing of the organic EL display device 1.

[0086] In this embodiment of the organic EL display device 1, the planarization film 50 is constructed by stacking a first planarization film 52 and a second planarization film 56. The recess 58 is formed by dividing the upper second planarization film 56, which is located above the first planarization film 52, into regions corresponding to the pixel electrodes 62, thereby exposing the lower first planarization film 52 at the bottom. This makes it easy to realize a configuration in which the recess 58 does not penetrate the planarization film 50.

[0087] In this embodiment of the organic EL display device 1, the bank 64 is made of a photosensitive resin. This allows the bank 64 to be formed without using a resist formed by photolithography as a mask to pattern the coating film. Therefore, the manufacturing process of the organic EL display device 1 can be reduced.

[0088] In this embodiment of the organic EL display device 1, the bank 64 is provided so as to cover the outer peripheral edge of the pixel electrode 62. The outer peripheral end surface of the pixel electrode 62 tends to form a steep step with respect to the surface of the planarization film 50. By covering the outer peripheral edge of the pixel electrode 62 with the bank 64, the surface on which the organic EL layer 66 is formed can be made relatively smooth. This is advantageous in preventing leakage between the pixel electrode 62 and the common electrode 68 due to thinning caused by the step on the surface on which the organic EL layer 66 is formed.

[0089] In the organic EL display device 1 of this embodiment, the height of the bank 64 from the surface of the pixel electrode 62 is 0.2 μm or more and 1.0 μm or less. When the height of the bank 64 is 0.2 μm or more, the outer edge of the pixel electrode 62 can be suitably covered, preventing leakage between the pixel electrode 62 and the common electrode 68. When the height of the bank 64 is 1.0 μm or less, the relatively low height of the bank 64 from the surface of the pixel electrode 62 makes it less likely for uneven light emission to occur in the organic EL element 61.

[0090] In the organic EL display device 1 of this embodiment, the depth of the recess 58 is 1 μm or more and 3 μm or less. If the depth of the recess 58 is 1 μm or more, the thickness of the bank 64 can be secured, and the light-shielding properties of the bank 64 can be suitably improved. If the depth of the recess 58 is 3 μm or less, sufficient light-shielding properties can be obtained for the bank 64 without making the planarization film 50 excessively thick.

[0091] In this embodiment of the organic EL display device 1, the organic EL elements 61 include multiple types of organic EL elements 61 having different emission colors. The organic EL elements 61 with different emission colors are separated by a bank 64. The bank 64 is provided in a recess 58 and extends wall-like to the lower layer than the organic EL elements 61. Therefore, the light emitted by the organic EL elements 61 that travels from the lower layer of the organic EL element 61 to the region corresponding to the adjacent organic EL element 61 is blocked by the bank 64. This is advantageous in preventing the mixing of colors of light from adjacent organic EL elements 61.

[0092] In the manufacturing method of the organic EL display device 1 of this embodiment, a planarized film 50 is patterned to form a recess 58, and a bank 64 is formed so as to fill the recess 58. Then, in the step of forming the organic EL layer 66 so as to cover the bank 64, the lower functional layer 66a, the light-emitting layer 66b, and the upper functional layer 66c are formed by a coating method. This ensures sufficient thickness of the bank 64 and provides sufficient light shielding, and also suppresses the relative thickness of the organic material forming the organic EL layer 66 along the periphery of the bank 64, making it less likely for uneven light emission to occur in the organic EL element 61.

[0093] In the manufacturing method of the organic EL display device 1 of this embodiment, a first planarization film 52 and a second planarization film 56 are stacked, and recesses 58 are formed by dividing the second planarization film 56 into regions corresponding to the pixel electrodes 62. This makes it easy to realize a configuration in which the recesses 58 do not penetrate the planarization film 50. If the recesses 58 do not penetrate the planarization film 50, the circuit configuration layer 20 can be covered and protected by the planarization film 50. This makes it possible to suppress damage to the circuit configuration layer 20 caused by the process of forming the pixel electrodes 62.

[0094] In the manufacturing method of the organic EL display device 1 of this embodiment, a bank 64 is formed using a photosensitive resin. In this process, the exposure treatment performed on the photosensitive resin coating requires light to reach the interior of the coating to react with the photosensitive resin. Therefore, there is a limit to how high the optical density of the photosensitive resin can be. In other words, a photosensitive resin with such a high optical density that the light irradiated during the exposure treatment does not reach the interior cannot be used. In such a manufacturing method of the organic EL display device 1, the technology of this disclosure is effective.

[0095] 《First Modified Example》 As shown in Figure 7, in this first modified example of the organic EL display device 1, the planarization film 50 is made of a single layer film. The recess 58 in this example is provided without penetrating the planarization film 50.

[0096] The planarization film 50 is not divided by the recess 58 and extends continuously across the entire display area DA. The portion of the planarization film 50 corresponding to the recess 58 is thinner than the other portions. In this example, the bottom of the recess 58 is formed by the planarization film 50. Contact holes Hc for connecting the pixel electrode 62 to a predetermined TFT 40 are formed in the planarization film 50.

[0097] To manufacture the organic EL display device 1 of this example, as shown in the upper diagram of Figure 8A, a circuit configuration layer 20 is formed on the substrate layer 10 in the same manner as in the above embodiment. In the subsequent planarization film formation step, the planarization film 50 is patterned using a multi-gradation mask 102 such as a halftone mask or a graytone mask, thereby forming recesses 58 in the planarization film 50 at the same time as forming the planarization film.

[0098] Specifically, a photosensitive resin is applied to a substrate on which the circuit configuration layer 20 is formed, using a known coating method. Furthermore, the photosensitive resin coating film 104 is subjected to pre-baking, exposure, development, and post-baking. At this time, as shown in the intermediate view of Figure 8A, in the exposure process, light L is irradiated onto the photosensitive resin coating film 104 through a multi-gradation mask 102, causing the photosensitive resin to react with the light L.

[0099] The multi-gradation mask 102 is configured to allow light L to pass through unnecessary parts of the photosensitive resin coating film 104, partially block light L to the recess 58 formation area, and completely block light L to other areas. By using such a multi-gradation mask 102, a planarization film 50 is partially thinned and patterned from the same photosensitive resin coating film 104 to form a planarization film 50 having contact holes Hc and recesses 58, as shown in the lower diagram of Figure 8A.

[0100] In the subsequent pixel electrode formation step, pixel electrodes 62 are formed on the planarized film 50 in the same manner as in the above embodiment, as shown in the upper figure of Figure 8B. Furthermore, in the bank formation step, in the same manner as in the above embodiment, a colored photosensitive resin having visible light absorption properties is applied to fill the recesses 58, and then the coated film of the photosensitive resin is patterned to form banks 64 between adjacent pixel electrodes 62 on the surface of the planarized film 50, as shown in the lower figure of Figure 8B.

[0101] In the subsequent organic EL layer formation step, an organic EL layer 66 is formed to cover the pixel electrode 62 and bank 64, as shown in the upper diagram of Figure 8C, in the same manner as in the above embodiment. Then, in the common electrode formation step, a common electrode 68 is formed to overlap each pixel electrode 62 via the organic EL layer 66, as shown in the lower diagram of Figure 8C, in the same manner as in the above embodiment.

[0102] Thereafter, the organic EL display device 1 can be manufactured by performing the sealing film formation step and other steps in the same manner as in the above embodiment.

[0103] -Features of the First Modified Example- In the manufacturing method of the organic EL display device 1 of this first modified example, the planarization film 50 is patterned using a multi-gradation mask 102 to form recesses 58. This reduces the number of steps involved in forming the planarization film 50 including the recesses 58 compared to the case where the planarization film 50 is composed of a first planarization film 52 and a second planarization film 56, and the recesses 58 are formed by patterning the upper first planarization film 52.

[0104] 《Second Modification》 In order to manufacture the organic EL display device 1 of the first modification described above, recesses 58 may be formed in the planarization film 50 in conjunction with the formation of the pixel electrodes 62.

[0105] In the planarization film formation process, a photosensitive resin is applied to the substrate on which the circuit configuration layer 20 is formed. Furthermore, the photosensitive resin coating is pre-baked, exposed, developed, and post-baked, and the coating is patterned to form a planarization film 50 having contact holes Hc, as shown in the upper diagram of Figure 9A. At this stage, the recesses 58 are not formed.

[0106] In the subsequent pixel electrode formation step, a conductive film 106 is formed on the substrate on which the planarization film 50 is formed, in the same manner as in the above embodiment, as shown in the intermediate view of Figure 9A. Subsequently, as shown in the lower view of Figure 9A, a resist 108 is formed on the conductive film 106 in the region where the pixel electrode 62 is to be formed by a known photoprocess. The resist 108 has openings in the portions corresponding to the formation of recesses 58 in the planarization film 50.

[0107] Next, the conductive film 106 is dry-etched using the resist 108 as a mask. This patterns the conductive film 106 to form the pixel electrodes 62, as shown in the upper part of Figure 9B. Furthermore, the planarization film 50 is patterned by ashing it for a predetermined time, using the resist 108 and the pixel electrodes 62 as masks. This removes a portion of the planarization film 50 between the pixel electrodes 62 in the thickness direction, as shown in the lower part of Figure 9B, forming recesses 58 in the planarization film 50.

[0108] Thereafter, the bank formation process, organic EL layer formation process, common electrode formation process, sealing film formation process, and other processes may be carried out in the same manner as in the above embodiment.

[0109] -Features of the second modified example- In this second modified example of the manufacturing method for the organic EL display device 1, the resist 108 used as a mask when forming the pixel electrode 62 is used as a mask when forming the recess 58 in the planarization film 50. By forming the pixel electrode 62 and the recess 58 of the planarization film 50 with the same resist 108 as a mask, the alignment margin between the pixel electrode 62 and the recess 58 can be eliminated. This is advantageous for increasing the resolution and aperture ratio of the organic EL display device 1.

[0110] <Third Modification> As shown in Figure 10, in this third modification of the organic EL display device 1, the planarization film 50 is made of a single layer film. The recess 58 in this example is provided penetrating the planarization film 50.

[0111] The planarization film 50 is divided into regions corresponding to the pixel electrodes 62. Recesses 58 are formed between adjacent planarization films 50, exposing the lower layer of the planarization film 50 to the bottom. In this example, the lower layer of the planarization film 50 is the circuit configuration layer 20 (more precisely, the insulating film, electrodes, or wiring that constitute the uppermost layer of the circuit configuration layer 20). Contact holes Hc are formed in the planarization film 50 for connecting the pixel electrodes 62 to a predetermined TFT 40.

[0112] To manufacture the organic EL display device 1 of this example, a circuit configuration layer 20 is formed on the substrate layer 10 in the same manner as in the above embodiment, as shown in the upper figure of Figure 11A. In the subsequent planarization film formation step, a photosensitive resin is applied to the substrate on which the circuit configuration layer 20 is formed by a known coating method. Furthermore, the photosensitive resin coating film is subjected to pre-baking, exposure, development, and post-baking to pattern the coating film and form a planarization film 50 having contact holes Hc and recesses 58, as shown in the lower figure of Figure 11A.

[0113] In the subsequent pixel electrode formation step, pixel electrodes 62 are formed on the planarized film 50 in the same manner as in the above embodiment, as shown in the upper figure of Figure 11B. Furthermore, in the bank formation step, in the same manner as in the above embodiment, a colored photosensitive resin having visible light absorption properties is applied to fill the recesses 58, and then the coated film of the photosensitive resin is patterned to form banks 64 between adjacent pixel electrodes 62 on the surface of the planarized film 50, as shown in the lower figure of Figure 11B.

[0114] In the subsequent organic EL layer formation step, an organic EL layer 66 is formed to cover the pixel electrodes 62 and bank 64, as shown in the upper diagram of Figure 11C, in the same manner as in the above embodiment. Then, in the common electrode formation step, a common electrode 68 is formed to overlap each pixel electrode 62 via the organic EL layer 66, as shown in the lower diagram of Figure 11C, in the same manner as in the above embodiment.

[0115] Thereafter, the organic EL display device 1 can be manufactured by performing the sealing film formation step and other steps in the same manner as in the above embodiment.

[0116] -Features of the Third Modified Example- In this third modified example of the organic EL display device 1, the recess 58 is formed such that the lower layer of the planarization film 50 is exposed at the bottom by dividing the planarization film 50 into regions corresponding to the pixel electrodes 62. This allows the recess 58 to be formed deeper than when the recess 58 does not penetrate the planarization film 50. As a result, the bank 64 provided including the inside of the recess 58 can be suitably made thicker, and the light-shielding properties of the bank 64 can be further improved.

[0117] 《Fourth Modification》 As shown in Figure 12, in this fourth modification of the organic EL display device 1, the planarization film 50 is made of a single layer film. The recess 58 in this example is provided penetrating the planarization film 50. A passivation film 46 is provided on the surface of the circuit configuration layer 20 so as to cover various wirings, TFTs 40 and capacitors 42. The passivation film 46 is an example of an inorganic insulating film. The passivation film 46 is formed of an inorganic insulating material such as silicon oxide, silicon nitride, or silicon oxynitride.

[0118] The planarization film 50 is divided into regions corresponding to the pixel electrodes 62. Recesses 58 are formed between adjacent planarization films 50, exposing the lower layer of the planarization film 50 to the bottom. In this example, the lower layer of the planarization film 50 is a passivation film 46. That is, the passivation film 46 is exposed at the bottom of the recesses 58. Contact holes Hc are formed in the planarization film 50 and the passivation film 46 for connecting the pixel electrodes 62 to a predetermined TFT 40.

[0119] To manufacture the organic EL display device 1 of this example, a circuit configuration layer 20 is formed on the substrate layer 10, as shown in the upper view of Figure 13A, in the same manner as in the above embodiment. Next, a passivation film formation process is performed. In the passivation film formation process, an inorganic insulating film is formed on the substrate on which the circuit configuration layer 20 is formed, for example by plasma CVD. Furthermore, the inorganic insulating film is patterned by photolithography to form contact holes Hc in the inorganic insulating film. In this way, a passivation film 46 is formed, as shown in the intermediate view of Figure 13A.

[0120] In the subsequent planarization film formation step, a photosensitive resin is applied to the substrate on which the passivation film 46 has been formed using a known coating method. Furthermore, the photosensitive resin coating is subjected to pre-baking, exposure, development, and post-baking, and the coating is patterned to form a planarization film 50 having contact holes Hc and recesses 58, as shown in the lower diagram of Figure 13A.

[0121] In the subsequent pixel electrode formation step, pixel electrodes 62 are formed on the planarized film 50 in the same manner as in the above embodiment, as shown in the upper figure of Figure 13B. Furthermore, in the bank formation step, in the same manner as in the above embodiment, a colored photosensitive resin having visible light absorption properties is applied to fill the recesses 58, and then the coated film of the photosensitive resin is patterned to form banks 64 between adjacent pixel electrodes 62 on the surface of the planarized film 50, as shown in the lower figure of Figure 13B.

[0122] In the subsequent organic EL layer formation step, as shown in the upper diagram of Figure 13C, an organic EL layer 66 is formed to cover the pixel electrodes 62 and bank 64 in the same manner as in the above embodiment. Then, in the common electrode formation step, as shown in the lower diagram of Figure 13C, a common electrode 68 is formed to overlap each pixel electrode 62 via the organic EL layer 66, in the same manner as in the above embodiment.

[0123] Thereafter, the organic EL display device 1 can be manufactured by performing the sealing film formation step and other steps in the same manner as in the above embodiment.

[0124] -Features of the fourth modified example- In this fourth modified example of the organic EL display device 1, the passivation film 46 provided on the surface of the circuit configuration layer 20 is exposed at the bottom of the recess 58. Various wirings, TFTs 40 and capacitors 42 included in the circuit configuration layer 20 are covered by the passivation film 46. As a result, damage to the circuit configuration layer 20 caused by the process of forming the pixel electrodes 62 during the manufacturing of the organic EL display device 1 can be suppressed.

[0125] 《Fifth Modification》 In order to manufacture the organic EL display device 1 of the fourth modification described above, recesses 58 may be formed in the planarization film 50 in conjunction with the formation of the pixel electrodes 62.

[0126] In this case, during the planarization film formation process, a photosensitive resin is applied to the substrate on which the passivation film 46 is formed. Furthermore, the photosensitive resin coating is pre-baked, exposed, developed, and post-baked, and the coating is patterned to form a planarization film 50 having contact holes Hc, as shown in the upper diagram of Figure 14A. At this stage, the recesses 58 are not formed.

[0127] In the subsequent pixel electrode formation step, a conductive film 106 is formed on the substrate on which the planarization film 50 is formed, in the same manner as in the above embodiment, as shown in the intermediate view of Figure 14A. Subsequently, as shown in the lower view of Figure 14A, a resist 108 is formed on the conductive film 106 in the region where the pixel electrode 62 is to be formed by a known photoprocess. The resist 108 has openings in the portions corresponding to the formation of recesses 58 in the planarization film 50.

[0128] Next, the conductive film 106 is dry-etched using the resist 108 as a mask. This patterns the conductive film 106 to form the pixel electrodes 62, as shown in the upper part of Figure 14B. Furthermore, the planarization film 50 is patterned by ashing, using the resist 108 and the pixel electrodes 62 as masks. This removes the portion of the planarization film 50 between the pixel electrodes 62 over its entire thickness, as shown in the lower part of Figure 14B, forming recesses 58 in the planarization film 50.

[0129] Thereafter, the bank formation process, organic EL layer formation process, common electrode formation process, sealing film formation process, and other processes may be carried out in the same manner as in the above embodiment.

[0130] -Features of the Fifth Modified Example- In this fifth modified example of the manufacturing method for the organic EL display device 1, the resist 108 used as a mask when forming the pixel electrode 62 is used as a mask when forming the recess 58 in the planarization film 50. By forming the pixel electrode 62 and the recess 58 of the planarization film 50 with the same resist 108 as a mask, the alignment margin between the pixel electrode 62 and the recess 58 can be eliminated. This is advantageous for increasing the resolution and aperture ratio of the organic EL display device 1.

[0131] <Other Embodiments> In the above embodiment, the height of the bank 64 from the surface of the pixel electrode 62 was set to be 0.2 μm or more and 1.0 μm or less, but it is not limited to this. The height of the bank may be less than 0.2 μm or greater than 1.0 μm.

[0132] In the above embodiment, the optical density of the bank 64 at the wavelength of visible light per 1 μm thickness is set to be 0.5 or more and 1.5 or less, but it is not limited to this. The optical density of the bank 64 may be less than 0.5, and may be greater than 1.5 as long as it is possible to react the photosensitive resin making up the bank 64 with light to the interior.

[0133] In the above embodiment, a positive-type photosensitive resin having black color was given as an example of the colored resin forming bank 64, but it is not limited to this. The colored resin forming bank 64 may be a colored photosensitive resin other than black, as long as it has the ability to absorb visible light. Furthermore, bank 64 may be formed from a negative-type photosensitive resin or from a non-photosensitive resin.

[0134] In the above embodiment, the planarization film 50 is assumed to be composed of a first planarization film 52 and a second planarization film 56, but it is not limited to this. In addition to the first planarization film 52 and the second planarization film 56, the planarization film 50 may further include a third planarization film provided on the second planarization film 56, or it may be composed of four or more layers of planarization films stacked together.

[0135] In the above embodiment, the lower functional layer 66a, the light-emitting layer 66b, and the upper functional layer 66c are formed on the substrate on which the bank 64 is formed by a known coating method, but the embodiment is not limited to this. Any of the lower functional layer 66a, the light-emitting layer 66b, and the upper functional layer 66c may be formed by a method other than coating, such as vacuum deposition.

[0136] In the above embodiment, each pixel PX is assumed to be composed of three sub-pixels SP, but this is not limited to this. The sub-pixels SP constituting each pixel PX may be four or more colors. Also, the sub-pixels SP constituting each pixel PX are assumed to be arranged in a stripe pattern, but this is not limited to this. The arrangement of the multiple sub-pixels SP may be other arrangements, such as a pentile arrangement.

[0137] Furthermore, each pixel PX may not be divided into multiple subpixels SP, but rather composed of a single organic EL element 61. Such an organic EL element 61 performs monochrome display, such as grayscale.

[0138] In the above embodiment, the light-emitting layer 66b is provided individually for each sub-pixel SP, but this is not limited to this. The light-emitting layer 66b may be provided in common as a continuous unit for multiple sub-pixels SP. In this case, the organic EL display device 1 may provide a color filter or the like to express the color tone at each sub-pixel SP.

[0139] In the above embodiment, each TFT 40 is assumed to be of the top-gate type, but this is not limited to this configuration. Each TFT 40 may also be configured as a bottom-gate type.

[0140] In the above embodiment, the pixel electrode 62 functions as the anode and the common electrode 68 functions as the cathode, but this is not limited to this configuration. The organic EL display device 1 may be configured such that the pixel electrode 62 functions as the cathode and the common electrode 68 functions as the anode. In this case, the organic EL layer 66 has an inverted stacked structure.

[0141] In the above embodiment, the substrate of the organic EL display device 1 is a substrate layer 10 made of a thin resin film, but it is not limited to this. As the substrate, it is possible to use a substrate made of any material, such as a plastic substrate made of polyethylene terephthalate (PET) or a glass substrate.

[0142] In the above embodiments, an organic EL display device 1 was given as an example of the display device according to the present disclosure, but the invention is not limited thereto. The technology of the present disclosure is applicable to a display device having a plurality of light-emitting elements. An example of such a display device is a quantum dot display device. A quantum dot display device is a display device that uses a quantum dot light-emitting element, also called a QLED (Quantum-dot Light Emitting Diode), which has a quantum dot-containing layer, as the light-emitting element.

[0143] As described above, preferred embodiments have been explained as examples of the technology of this disclosure. However, the technology of this disclosure is not limited thereto and can be applied to embodiments that are modified, replaced, added to, or omitted as appropriate. It will be understood by those skilled in the art that various further modifications are possible to the above embodiments without departing from the spirit of the technology of this disclosure, and that such modifications also fall within the scope of the technology of this disclosure.

[0144] Furthermore, the designations "First," "Second," etc., mentioned above are merely used to distinguish the terms to which these designations are attached, and do not limit the number or order of those terms.

[0145] As described above, this disclosure is useful for display devices and methods for manufacturing the same.

[0146] 1 Organic EL display device (display device) 20 Circuit configuration layer 22 Gate line (wiring) 24 Light emission control line (wiring) 26 Power branch line (wiring) 28 Source line (wiring) 30 Power line (wiring) 32 First power main line (wiring) 34 Second power main line (wiring) 36 Lead line (wiring) 40 TFT (circuit element) 42 Capacitor (circuit element) 46 Passivation film (inorganic insulating film) 50 Planarization film 52 First planarization film 56 Second planarization film 58 Recess 61 Organic EL element (light-emitting element) 61r Red light-emitting element 61g Green light-emitting element 61b Blue light-emitting element 62 Pixel electrode 64 Bank 66 Organic EL layer (electroluminescence layer) 66b Light-emitting layer 68 Common electrode 102 Multi-gradation mask

Claims

1. A display device comprising: a circuit configuration layer including circuit elements and wiring; a planarization film provided on the circuit configuration layer; a plurality of light-emitting elements provided on the planarization film; and a bank extending between adjacent light-emitting elements, wherein each of the plurality of light-emitting elements has a pixel electrode individually provided on the planarization film, an electroluminescent layer provided on the pixel electrode, and a common electrode provided so as to overlap the pixel electrode via the electroluminescent layer; recesses formed on the surface of the planarization film between adjacent pixel electrodes, recesses toward the circuit configuration layer side; and the bank is made of a colored resin having visible light absorption properties, is provided to fill the recesses, and shields the lower layer between adjacent pixel electrodes.

2. A display device according to claim 1, wherein the recess is provided without penetrating the planarization film.

3. A display device according to claim 2, wherein the planarization film comprises a first planarization film and a second planarization film provided on the first planarization film, the second planarization film is divided into regions corresponding to the pixel electrodes, and the recesses are formed between adjacent second planarization films, exposing the first planarization film at the bottom.

4. A display device according to claim 1, wherein the planarization film is divided into regions corresponding to the pixel electrodes, and the recesses are formed between adjacent planarization films, exposing the lower layer of the planarization film to the bottom.

5. A display device according to claim 4, wherein an inorganic insulating film is provided on the surface of the circuit component layer so as to cover the circuit element and the wiring, and the inorganic insulating film is exposed at the bottom of the recess.

6. A display device according to any one of claims 1 to 5, wherein the colored resin forming the bank is a photosensitive resin.

7. A display device according to claim 6, wherein the optical density at the wavelength of visible light per 1 μm of thickness of the bank is 0.5 or more and 1.5 or less.

8. A display device according to any one of claims 1 to 7, wherein the bank is provided so as to cover the outer peripheral edge of the pixel electrode.

9. A display device according to any one of claims 1 to 8, wherein the bank is provided higher above the surface of the pixel electrode, and the height of the bank from the surface of the pixel electrode is 0.2 μm or more and 1.0 μm or less.

10. A display device according to any one of claims 1 to 9, wherein the depth of the recess is 1.0 μm or more and 3.0 μm or less.

11. A display device according to any one of claims 1 to 10, wherein the plurality of light-emitting elements are composed of a plurality of types of light-emitting elements having different light-emitting colors.

12. A display device according to claim 11, wherein the plurality of types of light-emitting elements include a red light-emitting element having a red light-emitting layer in the electroluminescent layer, a green light-emitting element having a green light-emitting layer in the electroluminescent layer, and a blue light-emitting element having a blue light-emitting layer in the electroluminescent layer.

13. A display device according to any one of claims 1 to 12, wherein the light-emitting element is an organic electroluminescent element or a quantum dot light-emitting element.

14. A method for manufacturing a display device according to claim 1, comprising: a circuit configuration layer formation step of forming the circuit configuration layer on a substrate; a planarization film formation step of forming the planarization film on the circuit configuration layer; a pixel electrode formation step of forming the pixel electrodes on the planarization film; a bank formation step of forming the bank between adjacent pixel electrodes on the surface of the planarization film; an electroluminescence layer formation step of forming the electroluminescence layer so as to cover the bank; and a common electrode formation step of forming the common electrode so as to overlap the pixel electrodes via the electroluminescence layer, wherein in the planarization film formation step, the planarization film is patterned to form the recesses; in the bank formation step, a colored resin having visible light absorption properties is applied to fill the recesses, and then the applied resin film is patterned to form the bank; and in the electroluminescence layer formation step, at least a portion of the electroluminescence layer is formed by a coating method.

15. A method for manufacturing a display device according to claim 14, wherein in the planarization film formation step, a first planarization film is formed as the planarization film, and then a second planarization film is formed on the first planarization film, divided into regions for forming the pixel electrodes, thereby forming the recesses.

16. A method for manufacturing a display device according to claim 14, wherein in the planarization film formation step, the recess is formed in the planarization film by patterning the planarization film using a multi-gradation mask.

17. A method for manufacturing a display device according to claim 14, wherein in the pixel electrode formation step, a conductive film is formed on the planarization film, a resist is formed in the region of the conductive film where the pixel electrode is to be formed, and the conductive film is patterned by etching using the resist as a mask to form the pixel electrode; and in the planarization film formation step, the planarization film is patterned by ashing using the resist and the pixel electrode as masks to form the recess.

18. A method for manufacturing a display device according to any one of claims 14 to 17, wherein in the bank formation step, a photosensitive resin is applied as the colored resin, and the coated film of the photosensitive resin is subjected to a process including exposure and development to form the bank.

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