Method for manufacturing display device

Abstract

In this light-emitting element layer formation step for forming a light-emitting element layer in which a plurality of first electrodes, a plurality of light-emitting functional layers, and a common second electrode are sequentially stacked, ink is discharged from a plurality of nozzles while an application head (110) having the plurality of nozzles is moved so that the plurality of light-emitting functional layers are formed by an inkjet method; and, in this light-emitting functional layer formation step constituting the light-emitting element layer formation step, after a trial ink injection is performed on the outside (Ra) of a plurality of display regions (D) on a base mother substrate (100), the plurality of light-emitting functional layers are sequentially formed in each of the plurality of display regions (D), by continuously moving the application head (110).

Description

Method for manufacturing a display device

[0001] The present invention relates to a method for manufacturing a display device.

[0002] In recent years, as a display device replacing a liquid crystal display device, particularly, a display device including an organic light emitting diode (hereinafter also referred to as "OLED"), an inorganic light emitting diode, and a quantum dot light emitting diode (hereinafter also referred to as "QLED") has attracted high attention because it can achieve low power consumption, thinning, and high image quality. The display device including this QLED includes, for example, a base substrate, a thin film transistor (hereinafter also referred to as "TFT") layer provided on the base substrate, a QLED element layer provided on the TFT layer, and a sealing film provided on the QLED element layer. Here, the QLED element constituting the QLED element layer includes, for example, a first electrode provided on the TFT layer, a QLED layer provided as a light emitting functional layer on the first electrode, and a second electrode provided on the QLED layer. The QLED layer includes, for example, a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer, and is formed by a vacuum evaporation method, an inkjet method, a slit coating method, or the like.

[0003] For example, Patent Document 1 discloses a method for manufacturing a display device having a discharge step of discharging ink containing a color conversion material from a discharge head toward a position where a pixel is formed on a substrate, a light irradiation step of irradiating the ink discharged from the discharge head with light having a predetermined wavelength from a light source, a light intensity measurement step of measuring the intensity of color-converted light emitted from the ink irradiated with the light having the predetermined wavelength, and a control step of controlling subsequent discharge toward the position where the pixel is formed based on the measurement result of the light intensity measurement step.

[0004] Japanese Patent Application Laid-Open No. 2020-194018

[0005] Incidentally, when using an inkjet method to form hole injection layers, electron transport layers, etc., of a QLED layer (light-emitting functional layer) by applying ink containing nanoparticles, for example, the solvent in the ink may evaporate at or near the nozzles of the inkjet head, potentially causing clogging of the nozzles due to ink aggregation or solidification. If this happens, streaky unevenness may occur in the coated film along the direction of the inkjet head's movement, resulting in an uneven film thickness of the light-emitting functional layer, so there is room for improvement.

[0006] The present invention has been made in view of these points, and its objective is to make the film thickness of the light-emitting functional layer uniform.

[0007] To achieve the above objective, the present invention provides a method for manufacturing a display device, comprising: a thin-film transistor layer formation step of forming thin-film transistor layers in each of the multiple display areas on a base substrate having a plurality of defined display areas; and a light-emitting element layer formation step of forming a light-emitting element layer on the thin-film transistor layer, in which a plurality of first electrodes, a plurality of light-emitting functional layers, and a common second electrode are sequentially stacked corresponding to a plurality of subpixels constituting the display area, wherein the light-emitting element layer formation step involves moving a coating head having a plurality of nozzles and ejecting ink from the plurality of nozzles to form the plurality of light-emitting functional layers by an inkjet method, characterized in that, in the light-emitting functional layer formation step of forming the plurality of light-emitting functional layers, after performing a test print of the ink outside the plurality of display areas on the base substrate, the coating head is continuously moved to sequentially form the plurality of light-emitting functional layers for each of the plurality of display areas.

[0008] According to the present invention, the film thickness of the light-emitting functional layer can be made as uniform as possible.

[0009] Figure 1 is a plan view showing a schematic configuration of a QLED display device according to the first embodiment of the present invention. Figure 2 is a plan view of the display area of ​​a QLED display device according to the first embodiment of the present invention. Figure 3 is a cross-sectional view of the display area of ​​a QLED display device according to the first embodiment of the present invention. Figure 4 is an equivalent circuit diagram of the TFT layer constituting the QLED display device according to the first embodiment of the present invention. Figure 5 is a cross-sectional view of the QLED layer constituting the QLED display device according to the first embodiment of the present invention. Figure 6 is a plan view showing a method for manufacturing a QLED display device according to the first embodiment of the present invention. Figure 7 is a plan view of a coating head used in the method for manufacturing a QLED display device according to the first embodiment of the present invention. Figure 8 is a plan view showing a method for manufacturing a QLED display device according to the second embodiment of the present invention. Figure 9 is a plan view showing a method for manufacturing a QLED display device according to the third embodiment of the present invention.

[0010] Embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the following embodiments.

[0011] 《First Embodiment》 Figures 1 to 7 show a first embodiment of the method for manufacturing a display device according to the present invention. In the following embodiments, a QLED display device equipped with a QLED element layer is exemplified as a display device equipped with a light-emitting element layer. Here, Figure 1 is a plan view showing the schematic configuration of the QLED display device 50 of this embodiment. Figures 2 and 3 are a plan view and a cross-sectional view of the display area D of the QLED display device 50. Figure 4 is an equivalent circuit diagram of the TFT layer 30 constituting the QLED display device 50. Figure 5 is a cross-sectional view of the QLED layer 36 constituting the QLED display device 50.

[0012] As shown in Figure 1, the QLED display device 50 includes, for example, a display area D for displaying an image, which is provided in a rectangular shape, and a frame area F provided in a frame shape around the display area D. In this embodiment, a rectangular display area D is used as an example, but this rectangular shape also includes substantially rectangular shapes such as shapes with arc-shaped sides, shapes with arc-shaped corners, and shapes with notches in part of the sides.

[0013] In the display area D, as shown in Figure 2, multiple subpixels P are arranged in a matrix. Furthermore, in the display area D, as shown in Figure 2, for example, subpixels P having a red light-emitting region Lr for displaying red, subpixels P having a green light-emitting region Lg for displaying green, and subpixels P having a blue light-emitting region Lb for displaying blue are arranged adjacent to each other. Note that in the display area D, for example, one pixel is composed of three adjacent subpixels P having a red light-emitting region Lr, a green light-emitting region Lg, and a blue light-emitting region Lb.

[0014] A terminal portion T is provided at the positive end of the frame region F in the X direction in Figure 1, extending in one direction (the Y direction in Figure 1). Furthermore, between the display region D and the terminal portion T, as shown in Figure 1, a bendable portion B is provided on the display region D side of the terminal portion T in the frame region F, extending in one direction (the Y direction in Figure 1), which can be bent, for example, 180 degrees (in a U shape) with the Y direction in Figure 1 as the axis of bending.

[0015] As shown in Figure 3, the QLED display device 50 comprises a resin substrate 10 provided as a base substrate, a TFT layer 30 provided on the resin substrate 10, a QLED element layer 40 provided on the TFT layer 30 as a light-emitting element layer, and a sealing film 45 provided on the QLED element layer 40.

[0016] The resin substrate 10 is made of, for example, polyimide resin.

[0017] As shown in Figure 3, the TFT layer 30 comprises a base coat film 11 provided on a resin substrate 10, a plurality of first TFTs 9a, a plurality of second TFTs 9b, and a plurality of capacitors 9c provided on the base coat film 11, and a protective insulating film 19 and a planarization film 20 sequentially provided on each first TFT 9a, each second TFT 9b, and each capacitor 9c. Here, as shown in Figure 2, the TFT layer 30 is provided with a plurality of gate lines 14g extending parallel to each other in the X direction in the figure. Also, as shown in Figure 2, the TFT layer 30 is provided with a plurality of source lines 18f extending parallel to each other in a direction intersecting (orthogonal to) the plurality of gate lines 14g, i.e., in the Y direction in the figure. Also, as shown in Figure 2, the TFT layer 30 is provided with a plurality of power lines 18g extending parallel to each other in the Y direction in the figure. And, as shown in Figure 2, each power line 18g is provided adjacent to each source line 18f. Furthermore, in the TFT layer 30, as shown in Figure 4, a first TFT 9a, a second TFT 9b, and a capacitor 9c are provided in each subpixel P. In the TFT layer 30, as shown in Figure 3, a base coat film 11, a semiconductor film which will be a semiconductor layer 12a (described later), a first metal film which will be a gate insulating film 13, a gate line 14g, a first interlayer insulating film 15, a second metal film which will be an upper conductive layer 16c (described later), a second interlayer insulating film 17, a third metal film which will be a source line 18f or power line 18g, a protective insulating film 19, and a planarization film 20 are stacked in that order on the resin substrate 10.

[0018] The base coat film 11, gate insulating film 13, first interlayer insulating film 15, second interlayer insulating film 17, and protective insulating film 19 are composed of inorganic insulating films, such as single-layer or multilayer films, of silicon nitride, silicon oxide, or silicon oxynitride.

[0019] As shown in Figure 4, the first TFT 9a is electrically connected to the corresponding gate line 14g and source line 18f at each subpixel P. Here, as shown in Figure 3, the first TFT 9a comprises a semiconductor layer 12a provided on a base coat film 11, a gate electrode 14a provided on the semiconductor layer 12a via a gate insulating film 13, and a source electrode 18a and a drain electrode 18b provided spaced apart from each other on a second interlayer insulating film 17.

[0020] The semiconductor layer 12a is formed from a semiconductor film made of polysilicon, such as LTPS (low temperature polysilicon), and comprises a source region and a drain region defined to be spaced apart from each other, and a channel region defined between the source region and the drain region.

[0021] The gate electrode 14a is provided so as to overlap the channel region of the semiconductor layer 12a and is configured to control conductivity between the source region and the drain region of the semiconductor layer 12a. Here, the gate electrode 14a is formed of a first metal film, similar to the gate wire 14g, etc.

[0022] As shown in Figure 3, the source electrode 18a and the drain electrode 18b are electrically connected to the source region and drain region of the semiconductor layer 12a, respectively, via contact holes formed in the gate insulating film 13, the first interlayer insulating film 15, and the second interlayer insulating film 17. Here, the source electrode 18a and the drain electrode 18b are formed from a third metal film, similar to the source wire 18f and the power supply wire 18g.

[0023] As shown in Figure 4, the second TFT 9b is electrically connected to the corresponding first TFT 9a and power line 18g at each subpixel P. Here, as shown in Figure 3, the second TFT 9b comprises a semiconductor layer 12b provided on the base coat film 11, a gate electrode 14b provided on the semiconductor layer 12b via a gate insulating film 13, and a source electrode 18c and a drain electrode 18d provided spaced apart from each other on the second interlayer insulating film 17.

[0024] The semiconductor layer 12b, like the semiconductor layer 12a, is formed from a semiconductor film made of polysilicon such as LTPS, and comprises a source region and a drain region defined to be spaced apart from each other, and a channel region defined between the source region and the drain region.

[0025] The gate electrode 14b is provided so as to overlap the channel region of the semiconductor layer 12b and is configured to control conductivity between the source region and the drain region of the semiconductor layer 12b. Here, the gate electrode 14b is formed of a first metal film, similar to the gate wire 14g, etc.

[0026] As shown in Figure 3, the source electrode 18c and drain electrode 18d are electrically connected to the source region and drain region of the semiconductor layer 12b, respectively, through contact holes formed in the laminated film of the gate insulating film 13, the first interlayer insulating film 15, and the second interlayer insulating film 17. Here, the source electrode 18c and drain electrode 18d are formed from a third metal film, similar to the source wire 18f and power supply wire 18g.

[0027] In this embodiment, semiconductor layers 12a and 12b formed from a semiconductor film made of polysilicon are exemplified, but semiconductor layers 12a and 12b may be formed from a semiconductor film made of an oxide semiconductor such as In-Ga-Zn-O. Furthermore, the TFT layer 30 may have a hybrid structure in which a TFT having a semiconductor layer made of polysilicon and a TFT having a semiconductor layer made of an oxide semiconductor are provided.

[0028] As shown in Figure 4, the capacitor 9c is electrically connected to the corresponding first TFT 9a and power line 18g at each sub-pixel P. Here, as shown in Figure 3, the capacitor 9c comprises a lower conductive layer 14c formed of a first metal film, an upper conductive layer 16c formed of a second metal film, and a first interlayer insulating film 15 provided between the lower conductive layer 14c and the upper conductive layer 16c. The upper conductive layer 16c is electrically connected to the power line 18g via a contact hole formed in the second interlayer insulating film 17, as shown in Figure 3.

[0029] The planarized film 20 has a flat surface in the display area D and is made of an organic resin material such as polyimide resin.

[0030] As shown in Figure 3, the QLED element layer 40 comprises a plurality of third electrodes 31 stacked sequentially corresponding to a plurality of subpixels P, a common first edge cover 33, a plurality of first electrodes 34, a common second edge cover 35, a plurality of QLED layers 36, and a common second electrode 37. Here, in each subpixel P, the third electrode 31, the first electrode 34, the QLED layer 36, and the second electrode 37 constitute a QLED element 39, as shown in Figure 3, and in the QLED element layer 40, a plurality of QLED elements 39 are arranged in a matrix corresponding to a plurality of subpixels P.

[0031] As shown in Figure 3, the third electrode 31 is electrically connected to the drain electrode 18d of the second TFT 9b of each subpixel P via contact holes formed in the protective insulating film 19 and the planarization film 20. Here, the third electrode 31 is formed of a transparent conductive film such as indium tin oxide (hereinafter also referred to as "ITO") and has light transmittance.

[0032] The first edge cover 33 is provided in a grid pattern across the entire display area D, and as shown in Figures 3 and 4, it is provided to cover the peripheral end of the third electrode 31. The first edge cover 33 is made of, for example, an organic resin material such as polyimide resin or acrylic resin, or a polysiloxane-based SOG (spin on glass) material.

[0033] The first electrode 34 has the function of injecting holes into the QLED layer 36, and as shown in Figure 3, it is provided so as to cover the third electrode 31 that is exposed from the first edge cover 33. Furthermore, in order to improve the hole injection efficiency into the QLED layer 36, it is more preferable to form the first electrode 34 from a material with a large work function. Here, the first electrode 34 is formed from a laminated film in which a transparent conductive film such as ITO, a metal film such as silver (Ag), and a transparent conductive film such as ITO are sequentially laminated, and has light reflectivity.

[0034] The second edge cover 35 is provided in a grid pattern across the entire display area D, and as shown in Figure 3, it is provided to cover the peripheral end of the first electrode 34. Here, the second edge cover 35 is made of an inorganic insulating film, such as a single layer or multilayer film of silicon nitride, silicon oxide, or silicon oxynitride.

[0035] The QLED layer 36 is provided as a light-emitting functional layer and, as shown in Figure 5, comprises a hole injection layer 1, a hole transport layer 2, a light-emitting layer 3, and an electron transport layer 4 stacked sequentially on the first electrode 34. In this embodiment, a configuration in which each of the multiple light-emitting functional layers is a QLED layer 36 is illustrated, but at least one of the multiple light-emitting functional layers may be a QLED layer 36.

[0036] The hole injection layer 1, also called the anode buffer layer, has the function of bringing the energy levels of the first electrode 34 and the QLED layer 36 closer together, thereby improving the hole injection efficiency from the first electrode 34 to the QLED layer 36. Examples of materials constituting the hole injection layer 1 include, as organic materials, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, phenylenediamine derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, etc., and as inorganic materials, it contains at least one nanoparticle. The nanoparticle may, for example, contain nickel oxide (NiO) and further contain nitrate ions (NO₂). ３ － It includes ).

[0037] The hole transport layer 2 has the function of improving the efficiency of hole transport from the first electrode 34 to the QLED layer 36. Here, examples of materials that constitute the hole transport layer 2 include conventionally used materials such as porphyrin derivatives, aromatic tertiary amine compounds, styrylamine derivatives, polyvinylcarbazole, poly-p-phenylenevinylene, polysilane, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amine-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, hydrogenated amorphous silicon, hydrogenated amorphous silicon carbide, zinc sulfide, and zinc selenide. Furthermore, examples of materials that constitute the hole transport layer 2 include functional polymer materials such as poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl))diphenylamine)] (abbreviated as "TFB"), poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine] (abbreviated as "poly-TPD"), and polyvinylcarbazole (abbreviated as "PVK"). The material that constitutes the hole transport layer 2 may consist of only one of the above-mentioned materials, or may consist of two or more as appropriate.

[0038] The light-emitting layer 3 is a region in which holes and electrons are injected from the first electrode 34 and the second electrode 37, respectively, when a voltage is applied by the first electrode 34 and the second electrode 37, and where the holes and electrons recombine. Here, the light-emitting layer 3 is formed of a material with high luminescence efficiency. The light-emitting layer 3 includes, for example, a plurality of quantum dots as the light-emitting material. Furthermore, each quantum dot constituting the light-emitting layer 3 may have a core / shell structure including a core that emits light when excitons are used and a shell formed around the core to protect it. In this embodiment, the light-emitting layer 3 may also include an organic or inorganic ligand that coordinates to each quantum dot by forming a coordination bond with the outermost surface of each quantum dot.

[0039] In addition, in this embodiment, the "quantum dot" means a dot with a maximum width of 100 nm or less. Also, the shape of the quantum dot only needs to satisfy the above maximum width, and is not particularly restricted, and is not limited to a spherical three-dimensional shape (circular cross-sectional shape). Furthermore, the shape of the quantum dot may be, for example, a polygonal cross-sectional shape, a rod-shaped three-dimensional shape, a branched three-dimensional shape, a three-dimensional shape having irregularities on the surface, or a combination thereof.

[0040] The quantum dot is typically preferably made of a semiconductor. Here, the semiconductor preferably has a certain band gap. Also, the semiconductor may be any material that can emit light, and preferably contains at least the materials described below. Also, the semiconductor preferably can emit blue, green, and red light, respectively. Also, the semiconductor contains, for example, at least one selected from the group consisting of II-VI group compounds, III-V group compounds, chalcogenides, and perovskite compounds. Note that the II-VI group compound means a compound containing a group II element and a group VI element, and the III-V group compound means a compound containing a group III element and a group V element. Also, the group II element includes a group 2 element and a group 12 element, the group III element includes a group 3 element and a group 13 element, the group V element includes a group 5 element and a group 15 element, and the group VI element may include a group 6 element and a group 16 element.

[0041] The II-VI group compound contains, for example, at least one selected from the group consisting of MgS, MgSe, MgTe, CaS, CaSe, CaTe, SrS, SrSe, SrTe, BaS, BaSe, BaTe, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, HgS, HgSe, and HgTe.

[0042] The III-V group compound contains, for example, at least one selected from the group consisting of GaAs, GaP, InN, InAs, InP, and InSb.

[0043] The chalcogenide is a compound containing a group VIA (16) element, and contains, for example, CdS or CdSe. Also, the chalcogenide may contain mixed crystals thereof.

[0044] The perovskite compound has, for example, a composition represented by the general formula CsPbX ３ and contains at least one element X selected from the group consisting of, for example, Cl, Br, and I.

[0045] Note that the notation of the group number of elements using Roman numerals is based on the old IUPAC (International Union of Pure and Applied Chemistry) system or the old CAS (Chemical Abstracts Service) system, and the notation of the group number of elements using Arabic numerals is based on the current IUPAC system.

[0046] The electron transport layer 4 has a function of efficiently moving electrons to the light-emitting layer 3. Here, examples of the material constituting the electron transport layer 4 include, as organic compounds, oxadiazole derivatives, triazole derivatives, benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, tetracyanoanthraquinodimethane derivatives, diphenoquinone derivatives, fluorenone derivatives, silole derivatives, metal oxynoid compounds, etc., and inorganic materials can be used. Further, the material constituting the electron transport layer 4 may contain zinc oxide (ZnO), magnesium zinc oxide (MgZnO), etc. Furthermore, the material constituting the electron transport layer 4 may contain only one type of the above-described materials, or may contain two or more types as appropriate.

[0047] As shown in FIG. 3, the second electrode 37 is provided so as to cover each QLED layer 36 and the second edge cover 35. Further, the second electrode 37 has a function of injecting electrons into the QLED layer 36. Also, the second electrode 37 is more preferably composed of a material having a small work function in order to improve the electron injection efficiency into the QLED layer 36. Here, the second electrode 37 is formed of, for example, a transparent conductive film such as ITO and has light transmissibility.

[0048] As shown in Figure 3, the sealing film 45 is provided so as to cover the second electrode 37 and comprises a first inorganic sealing film 41, an organic sealing film 42, and a second inorganic sealing film 43 that are sequentially laminated on the second electrode 37, and has the function of protecting the QLED layer 36 of the QLED element 39 from moisture, oxygen, etc. Here, the first inorganic sealing film 41 and the second inorganic sealing film 43 are made of inorganic insulating films such as silicon nitride film, silicon oxide film, or silicon oxynitride film. The organic sealing film 42 is made of an organic resin material such as acrylic resin, epoxy resin, silicone resin, polyurea resin, parylene resin, polyimide resin, or polyamide resin.

[0049] The QLED display device 50 described above is configured such that, at each subpixel P, a gate signal is input to the first TFT 9a via the gate line 14g, turning the first TFT 9a into an ON state. A data signal is then written to the gate electrode 14b and capacitor 9c of the second TFT 9b via the source line 18f. A current from the power line 18g corresponding to the gate voltage of the second TFT 9b is supplied to the QLED layer 36 of the QLED element 39, causing the light-emitting layer 3 of the QLED layer 36 to emit light and display an image. In the QLED display device 50, even if the first TFT 9a is turned OFF, the gate voltage of the second TFT 9b is maintained by the capacitor 9c, so the light emission from the light-emitting layer 3 is maintained until the gate signal for the next frame is input.

[0050] In this embodiment, a QLED display device 50 equipped with a third electrode 31 and a first edge cover 33 is provided as an example, but the third electrode 31 and the first edge cover 33 may be omitted.

[0051] Furthermore, in this embodiment, a top-emission type QLED display device 50 is exemplified in which the third electrode 31 and the second electrode 37 are light-transmitting and the first electrode 34 is light-reflective. However, a bottom-emission type may also be used in which the third electrode 31 and the first electrode 34 are light-transmitting and the second electrode 37 is light-reflective.

[0052] Next, an example of a method for manufacturing the QLED display device 50 of this embodiment will be described. Here, Figure 6 is a plan view showing the method for manufacturing the QLED display device 50 of this embodiment. Figure 7 is a plan view of the coating head 110 used in the method for manufacturing the QLED display device 50. The method for manufacturing the QLED display device 50 of this embodiment comprises a TFT layer formation step, a QLED element layer formation step including a QLED layer formation step, a sealing film formation step, and a piece formation step.

[0053] <TFT Layer Formation Process> First, a base coat film 11 is formed on a resin substrate 100, which is formed on a glass substrate as a base substrate (with multiple display areas D defined), by sequentially depositing a silicon nitride film (approximately 50 nm thick) and a silicon oxide film (approximately 250 nm thick) using, for example, a plasma CVD (Chemical Vapor Deposition) method.

[0054] Next, an amorphous silicon film (approximately 50 nm thick) is deposited on the substrate surface on which the base coat film 11 is formed, for example by plasma CVD. The amorphous silicon film is then crystallized by laser annealing or the like to form a semiconductor film made of polysilicon. After that, the semiconductor film is patterned to form semiconductor layers 12a and 12b, etc., in each display area D.

[0055] Subsequently, a gate insulating film 13 is formed on the substrate surface on which the semiconductor layer 12a etc. is formed by depositing a silicon oxide film (approximately 100 nm thick) using, for example, a plasma CVD method.

[0056] Furthermore, a first metal film, such as a molybdenum film (approximately 200 nm thick), is formed on the substrate surface on which the gate insulating film 13 is formed, for example, by sputtering. Then, the first metal film is patterned to form gate lines 14g, gate electrodes 14a and 14b, etc., in each display area D.

[0057] Next, using the gate electrodes 14a and 14b as masks, impurity ions are doped into the semiconductor layers 12a and 12b to make a portion of the semiconductor layers 12a and 12b conductive, thereby forming a source region, a drain region, and a channel region in the semiconductor layers 12a and 12b, respectively.

[0058] Subsequently, a first interlayer insulating film 15 is formed on the substrate surface, where a portion of the semiconductor layers 12a and 12b have been made conductive, by sequentially depositing a silicon nitride film (approximately 150 nm thick) and a silicon oxide film (approximately 100 nm thick) using, for example, a plasma CVD method.

[0059] Furthermore, a second metal film, such as a molybdenum film (approximately 200 nm thick), is formed on the substrate surface on which the first interlayer insulating film 15 is formed, for example, by sputtering. After that, the second metal film is patterned to form an upper conductive layer 16c, etc., in each display area D.

[0060] Subsequently, a second interlayer insulating film 17 is formed on the substrate surface on which the upper conductive layer 16c etc. is formed, by sequentially depositing a silicon oxide film (approximately 300 nm thick) and a silicon nitride film (approximately 150 nm thick) using, for example, a plasma CVD method.

[0061] Next, on the substrate surface on which the second interlayer insulating film 17 is formed, contact holes are formed in each display area D by appropriately patterning the first gate insulating film 13, the first interlayer insulating film 15, and the second interlayer insulating film 17.

[0062] Subsequently, a third metal film is formed on the substrate surface where the contact holes are formed by sequentially depositing, for example, a titanium film (approximately 50 nm thick), an aluminum film (approximately 400 nm thick), and a titanium film (approximately 100 nm thick) by sputtering. After that, the third metal film is patterned to form source lines 18f, power lines 18g, source electrodes 18a and 18c, and drain electrodes 18b and 18d in each display area D.

[0063] Furthermore, a protective insulating film 19 is formed on the substrate surface on which the source lines 18f, etc., are formed, by depositing a silicon oxide film (approximately 250 nm thick) using, for example, a plasma CVD method.

[0064] Next, an acrylic photosensitive resin film (approximately 2 μm thick) is applied to the substrate surface on which the protective insulating film 19 is formed, for example, by a spin coating method or a slit coating method. Then, a planarization film 20 having contact holes is formed by pre-baking, exposure, development, and post-baking of the coated film.

[0065] Finally, the protective insulating film 19 exposed through the contact holes of the planarization film 20 is removed, allowing the contact holes to reach the drain electrode 18d of the second TFT 9b.

[0066] As described above, a TFT layer 30 can be formed in each display area D on the resin substrate 100.

[0067] <QLED element layer formation process> First, on the substrate surface on which the TFT layer 30 was formed in the TFT layer formation process described above, a transparent conductive film such as an ITO film (approximately 100 nm thick) is formed by, for example, sputtering, and then the transparent conductive film is patterned to form the third electrode 31 in each display area D.

[0068] Next, an acrylic-based negative-type photosensitive resin film (approximately 2 μm thick) is applied to the substrate surface on which the third electrode 31 is formed, for example, by a spin coating method or a slit coating method. Then, the coated film is subjected to pre-baking, exposure, development, and post-baking to form the first edge cover 33 in each display area D.

[0069] Subsequently, on the substrate surface on which the first edge cover 33 is formed, a transparent conductive film such as an ITO film (approximately 40 nm thick), a metal film such as an Ag film (approximately 20 nm thick), and another transparent conductive film such as an ITO film (approximately 40 nm thick) are sequentially deposited by, for example, a sputtering method. After these laminated films are patterned, the first electrode 34 is formed in each display area D.

[0070] Furthermore, an inorganic insulating film, such as a silicon nitride film (approximately 250 nm thick), is deposited on the substrate surface on which the first electrode 34, etc., is formed, for example, by plasma CVD. The inorganic insulating film is then patterned to form the second edge cover 35 in each display area D.

[0071] Next, as shown in Figure 6, a coating head 110, which has a plurality of nozzles N (see Figure 7) on its lower surface, is moved to the substrate surface on which the second edge cover 35 is formed. Ink containing nanoparticles in which the above-mentioned constituent materials are dissolved (dispersed) is ejected from the nozzles N, thereby forming a hole injection layer 1 in each display area D by inkjet. Here, the gap G (distance between centers) of the plurality of nozzles N provided on the coating head 110 is, for example, about 35 μm. In the resin substrate 100, the plurality of display areas D are each provided in a rectangular shape in a plan view, as shown in Figure 6, and are arranged in a line along their shorter side.

[0072] Specifically, when forming a hole injection layer 1 for multiple display areas D, as shown in Figure 6, first, before coating the first display area D, a test spray of ink is performed in the area Ra outside the display area D, for example, using a nozzle check pattern. The coating head 110 is moved to the positive side in the X direction (longitudinal direction) in the figure, and ink is ejected from the nozzle N to form a hole injection layer 1 over the entire first display area D. After that, a test spray of ink is performed in the area Rb outside the display area D. Subsequently, without ejecting ink, the coating head 110 is moved to the positive side in the Y direction (short direction) in Figure 6, and before coating the second display area D, a test spray of ink is performed in the area Rc outside the display area D. The coating head 110 is moved to the negative side in the X direction in Figure 6, and ink is ejected from the nozzle N to form a hole injection layer 1 over the entire second display area D. After that, a test spray of ink is performed in the area Rb outside the display area D. Subsequently, without ejecting ink, the coating head 110 is moved to the positive side in the Y direction in Figure 6, and before coating the third display area D, a test application of ink is performed in the area Rc outside the display area D. After ejecting ink from the nozzle N while moving the coating head 110 to the positive side in the X direction in Figure 6 to form a hole injection layer 1 over the entire third display area D, a test application of ink is performed in the area Rb outside the display area D. Furthermore, without ejecting ink, the coating head 110 is moved to the positive side in the Y direction in Figure 6, and before coating the fourth display area D, a test application of ink is performed in the area Rc outside the display area D. After ejecting ink from the nozzle N while moving the coating head 110 to the negative side in the X direction in Figure 6 to form a hole injection layer 1 over the entire fourth display area D, a test application of ink is performed in the area Rb outside the display area D. Finally, without ejecting ink, the coating head 110 is moved to the positive side in the Y direction in Figure 6, and before coating the fifth display area D, a test application of ink is performed in the area Rc outside the display area D. Then, while moving the coating head 110 to the positive side in the X direction in Figure 6, ink is ejected from the nozzle N to form a hole injection layer 1 over the entire fifth display area D, and then a test application of ink is performed in the area Rb outside the display area D.After performing test prints of the ink in regions Ra, Rb, and Rc, the coated film of the nozzle check pattern used for the test prints is observed with an optical microscope to check the condition of the nozzle N (whether or not it is clogged). If the nozzle N is clogged, the coating head 110 is stopped and the clogged nozzle N is cleaned or the coating head 110 is replaced.

[0073] Subsequently, on the substrate surface on which the hole injection layer 1 is formed, a hole transport layer 2 is formed in each display area D by an inkjet method, similar to the method for forming the hole injection layer 1 described above.

[0074] Subsequently, after forming a resist pattern on the substrate surface on which the hole transport layer 2 is formed, for example, a solution (dispersion) containing nanoparticles in which the above-mentioned constituent materials are dissolved (dispersed) is applied, and by the lift-off method, a red light-emitting layer, a green light-emitting layer, and a blue light-emitting layer are sequentially formed to form the light-emitting layer 3 in each display area D.

[0075] Furthermore, on the substrate surface on which the light-emitting layer 3 is formed, an electron transport layer 4 is formed in each display area D by an inkjet method, similar to the method for forming the hole injection layer 1 described above, to form a QLED layer 36 (QLED layer formation step).

[0076] Finally, a transparent conductive film, such as an ITO film (approximately 100 nm thick), is deposited on the substrate surface on which the QLED layer 36 is formed using a mask by sputtering to form the second electrode 37 in each display area D.

[0077] As described above, a QLED element layer 40 can be formed on each TFT layer 30.

[0078] <Encapsulation Film Formation Process> First, an inorganic insulating film, such as a silicon nitride film, a silicon oxide film, or a silicon oxynitride film, is deposited on the substrate surface on which the QLED element layer 40 was formed in the above QLED element layer formation process using a mask by plasma CVD to form a first inorganic encapsulation film 41 in each display area D.

[0079] Next, an organic resin material such as acrylic resin is deposited on the substrate surface on which the first inorganic encapsulation film 41 is formed, for example by an inkjet method, to form an organic encapsulation film 42 in each display area D.

[0080] Furthermore, an inorganic insulating film, such as a silicon nitride film, a silicon oxide film, or a silicon oxynitride film, is deposited on the substrate on which the organic encapsulation film 42 is formed, using a mask and a plasma CVD method to form a second inorganic encapsulation film 43 in each display area D, thereby forming the encapsulation film 45.

[0081] As described above, a sealing film 45 can be formed on each QLED element layer 40.

[0082] <Separation Process> First, a protective sheet (not shown) is attached to the substrate surface on which the sealing film 45 has been formed in the sealing film formation process described above. Then, by irradiating the resin substrate 100 with laser light from the glass substrate side, the glass substrate is peeled off from the bottom surface of the resin substrate 100. Furthermore, a protective sheet (not shown) is attached to the bottom surface of the resin substrate 100 from which the glass substrate has been peeled off.

[0083] Furthermore, a base substrate (a resin base substrate 100 and layers formed on the resin base substrate 100 (for example, a base coat film 11, a gate insulating film 13, a first interlayer insulating film 15, a second interlayer insulating film 17, a protective insulating film 19, a planarization film 20, etc.)) on which multiple QLED display devices 50 with protective sheets attached are arranged in a matrix is ​​divided into display areas D by, for example, irradiation with laser light, to cut out each QLED display device 50 individually and make them into individual pieces.

[0084] As described above, the QLED display device 50 of this embodiment can be manufactured.

[0085] As described above, according to the manufacturing method of the QLED display device 50 of this embodiment, in the QLED layer formation step of the QLED element layer formation step, after test printing of ink in the region Ra outside the multiple display regions D on the resin substrate 100, the coating head 110 is moved continuously to sequentially form multiple QLED layers 36 (hole injection layer 1, hole transport layer 2, electron transport layer 4) for each of the multiple display regions D. Here, in the test printing of ink in region Ra, the state of each nozzle N of the coating head 110 before coating the first display region D can be checked, so that the occurrence of streaky unevenness and the like in the QLED layer 36 (hole injection layer 1, hole transport layer 2, electron transport layer 4) is suppressed and the film thickness of the QLED layer 36 can be made uniform.

[0086] Furthermore, according to the manufacturing method of the QLED display device 50 of this embodiment, in the QLED layer formation step of the QLED element layer formation step, before ejecting ink to each of the second and subsequent display areas D, a test print of ink is performed in the area Rc outside each of those display areas D. Here, by test printing the ink in area Rc, the state of each nozzle N of the coating head 110 before coating each of the second and subsequent display areas D can be checked, so that the occurrence of streaky unevenness and the like in the QLED layer 36 (hole injection layer 1, hole transport layer 2, electron transport layer 4) is further suppressed, and the film thickness of the QLED layer 36 can be made even more uniform.

[0087] Furthermore, according to the manufacturing method of the QLED display device 50 of this embodiment, in the QLED layer formation step of the QLED element layer formation step, after ejecting ink to each of the multiple display areas D, a test print of the ink is performed in the area Rb outside each of the multiple display areas D. Here, the test print of the ink in area Rb allows the state of each nozzle N of the coating head 110 after coating each display area D to be checked, so the quality of the QLED layer 36 (hole injection layer 1, hole transport layer 2, electron transport layer 4) coated using each nozzle N can be indirectly checked.

[0088] Furthermore, according to the manufacturing method of the QLED display device 50 of this embodiment, in the QLED layer formation step of the QLED element layer formation step, the coating head 110 is moved in directions 180 degrees different from each other in a pair of adjacent display areas D among a plurality of display areas D, and ink is ejected in the forward and return paths of the coating head 110 to form the QLED layer 36 (hole injection layer 1, hole transport layer 2, electron transport layer 4), thereby increasing the manufacturing efficiency of the QLED display device 50.

[0089] 《Second Embodiment》 Figure 8 shows a second embodiment of the method for manufacturing a display device according to the present invention. Here, Figure 8 is a plan view showing the method for manufacturing the QLED display device 50 of this embodiment. In the following embodiments, the same reference numerals are used for parts that are the same as in Figures 1 to 7, and their detailed descriptions are omitted.

[0090] In the first embodiment described above, a method for manufacturing a QLED display device 50 was illustrated in which test printing of the ink was performed before and after application to each display area D. In this embodiment, however, a method for manufacturing a QLED display device 50 is illustrated in which test printing of the ink was performed before application to each display area D. Here, the QLED display device 50 of this embodiment is the same as the QLED display device 50 of the first embodiment described above, so its manufacturing method will be explained. Note that the manufacturing method of the QLED display device 50 of this embodiment includes a TFT layer formation step, a QLED element layer formation step including a QLED layer formation step, a sealing film formation step, and a piece formation step, similar to the first embodiment described above. Therefore, in this embodiment, the QLED layer formation step, which differs from the manufacturing method of the first embodiment, will be explained in detail.

[0091] First, in the QLED layer formation process of the first embodiment described above, as shown in Figure 8, on the substrate surface on which the second edge cover 35 is formed, an ink containing nanoparticles in which the above-mentioned constituent materials are dissolved (dispersed) is ejected from the nozzle N while moving the coating head 110, thereby forming a hole injection layer 1 in each display area D by inkjet method.

[0092] Specifically, when forming a hole injection layer 1 in multiple display areas D, as shown in Figure 8, first, before coating the first display area D, a test spray of ink is performed in the area Ra outside the display area D, for example, using a nozzle check pattern. The coating head 110 is moved to the positive side in the X direction in the figure, and ink is ejected from the nozzle N to form a hole injection layer 1 over the entire first display area D. Subsequently, without ejecting ink, the coating head 110 is moved to the positive side in the Y direction in Figure 8, and before coating the second display area D, a test spray of ink is performed in the area Rc outside the display area D. The coating head 110 is moved to the negative side in the X direction in the figure, and ink is ejected from the nozzle N to form a hole injection layer 1 over the entire second display area D. Subsequently, without ejecting ink, the coating head 110 is moved to the positive side in the Y direction in Figure 8, and before coating the third display area D, a test run of ink is performed in the area Rc outside the display area D. Then, while moving the coating head 110 to the positive side in the X direction in Figure 8, ink is ejected from the nozzle N to form a hole injection layer 1 over the entire third display area D. Furthermore, without ejecting ink, the coating head 110 is moved to the positive side in the Y direction in Figure 8, and before coating the fourth display area D, a test run of ink is performed in the area Rc outside the display area D. Then, while moving the coating head 110 to the negative side in the X direction in Figure 8, ink is ejected from the nozzle N to form a hole injection layer 1 over the entire fourth display area D. Finally, without ejecting ink, the coating head 110 is moved to the positive side in the Y direction in Figure 8, and before coating the fifth display area D, a test application of ink is performed in the area Rc outside the display area D. Then, while moving the coating head 110 to the positive side in the X direction in Figure 8, ink is ejected from the nozzle N to form a hole injection layer 1 over the entire fifth display area D. After performing the test application of ink in areas Ra and Rc, the coated film of the nozzle check pattern used for the test application is observed with an optical microscope to check the condition of the nozzle N (whether or not it is clogged). If the nozzle N is clogged, the coating head 110 is stopped and the clogged nozzle N is cleaned or the coating head 110 is replaced.

[0093] Subsequently, on the substrate surface on which the hole injection layer 1 is formed, a hole transport layer 2 is formed in each display area D by an inkjet method, similar to the method for forming the hole injection layer 1 described above.

[0094] Subsequently, after forming a resist pattern on the substrate surface on which the hole transport layer 2 is formed, for example, a solution (dispersion) containing nanoparticles in which the above-mentioned constituent materials are dissolved (dispersed) is applied, and by the lift-off method, a red light-emitting layer, a green light-emitting layer, and a blue light-emitting layer are sequentially formed to form the light-emitting layer 3 in each display area D.

[0095] Furthermore, on the substrate surface on which the light-emitting layer 3 is formed, an electron transport layer 4 is formed in each display area D by an inkjet method, similar to the method for forming the hole injection layer 1 described above, to form a QLED layer 36 (QLED layer formation step).

[0096] Subsequently, in the same manner as the manufacturing method of the first embodiment described above, the QLED display device 50 of this embodiment can be manufactured by forming a second electrode 37 in each display area D, thereby forming a QLED element layer 40 on each TFT layer 30, followed by a sealing film formation step and a piece formation step.

[0097] As described above, according to the manufacturing method of the QLED display device 50 of this embodiment, in the QLED layer formation step of the QLED element layer formation step, after test printing of ink in the region Ra outside the multiple display regions D on the resin substrate 100, the coating head 110 is moved continuously to sequentially form multiple QLED layers 36 (hole injection layer 1, hole transport layer 2, electron transport layer 4) for each of the multiple display regions D. Here, in the test printing of ink in region Ra, the state of each nozzle N of the coating head 110 before coating the first display region D can be checked, so that the occurrence of streaky unevenness and the like in the QLED layer 36 (hole injection layer 1, hole transport layer 2, electron transport layer 4) is suppressed and the film thickness of the QLED layer 36 can be made uniform.

[0098] Furthermore, according to the manufacturing method of the QLED display device 50 of this embodiment, in the QLED layer formation step of the QLED element layer formation step, before ejecting ink to each of the second and subsequent display areas D, a test print of ink is performed in the area Rc outside each of those display areas D. Here, the test print of ink in area Rc allows the state of each nozzle N of the coating head 110 before coating each of the second and subsequent display areas D to be checked, so that the occurrence of streaky unevenness and the like in the QLED layer 36 (hole injection layer 1, hole transport layer 2, electron transport layer 4) is further suppressed and the film thickness of the QLED layer 36 can be made even more uniform. Note that if the time between coating each of the first to fourth display areas D and the test print of ink in the area Rc corresponding to the next display area D is short, the quality of the QLED layer 36 (hole injection layer 1, hole transport layer 2, electron transport layer 4) coated in the previous display area D can be indirectly checked by the test print of ink in area Rc.

[0099] Furthermore, according to the manufacturing method of the QLED display device 50 of this embodiment, in the QLED layer formation step of the QLED element layer formation step, the coating head 110 is moved in directions 180 degrees different from each other in a pair of adjacent display areas D among a plurality of display areas D, and ink is ejected in the forward and return paths of the coating head 110 to form the QLED layer 36 (hole injection layer 1, hole transport layer 2, electron transport layer 4), thereby increasing the manufacturing efficiency of the QLED display device 50.

[0100] <Third Embodiment> Figure 9 shows a third embodiment of the method for manufacturing a display device according to the present invention. Here, Figure 9 is a plan view showing the method for manufacturing the QLED display device 50 of this embodiment.

[0101] In the first embodiment described above, a method for manufacturing a QLED display device 50 was illustrated in which test printing of the ink was performed before and after applying it to each display area D. In this embodiment, a method for manufacturing a QLED display device 50 is illustrated in which test printing of the ink was performed before applying it to the first display area D and after applying it to each display area D. Here, the QLED display device 50 of this embodiment is the same as the QLED display device 50 of the first embodiment described above, so its manufacturing method will be explained. Note that the manufacturing method of the QLED display device 50 of this embodiment includes a TFT layer formation step, a QLED element layer formation step including a QLED layer formation step, a sealing film formation step, and a piece formation step, similar to the first embodiment described above. Therefore, in this embodiment, the QLED layer formation step, which differs from the manufacturing method of the first embodiment, will be explained in detail.

[0102] First, in the QLED element layer formation process of the first embodiment described above, as shown in Figure 9, on the substrate surface on which the second edge cover 35 is formed, an ink containing nanoparticles in which the above-mentioned constituent materials are dissolved (dispersed) is ejected from the nozzle N while moving the coating head 110, thereby forming a hole injection layer 1 in each display area D by inkjet method.

[0103] Specifically, when forming a hole injection layer 1 in multiple display areas D, as shown in Figure 9, first, before applying to the first display area D, a test print of ink is performed in the area Ra outside the display area D, for example, using a nozzle check pattern. Then, while moving the application head 110 to the positive side in the X direction in Figure 9, ink is ejected from the nozzle N to form a hole injection layer 1 over the entire first display area D. After that, a test print of ink is performed in the area Rb outside the display area D. Subsequently, without ejecting ink, the application head 110 is moved to the positive side in the Y direction in Figure 9, and then, while moving to the negative side in the X direction in Figure 9, ink is ejected from the nozzle N to form a hole injection layer 1 over the entire second display area D. After that, a test print of ink is performed in the area Rb outside the display area D. Subsequently, without ejecting ink, the coating head 110 is moved to the positive side in the Y direction in Figure 9, and then, while continuing to move it to the positive side in the X direction in Figure 9, ink is ejected from the nozzle N to form a hole injection layer 1 over the entire third display area D. After that, a test print of the ink is performed in the area Rb outside that display area D. Furthermore, without ejecting ink, the coating head 110 is moved to the positive side in the Y direction in Figure 9, and then, while continuing to move it to the negative side in the X direction in Figure 9, ink is ejected from the nozzle N to form a hole injection layer 1 over the entire fourth display area D. After that, a test print of the ink is performed in the area Rb outside that display area D. Finally, without ejecting ink, the coating head 110 is moved to the positive side in the Y direction in Figure 9, and then, while continuing to move it to the positive side in the X direction in Figure 9, ink is ejected from the nozzle N to form a hole injection layer 1 over the entire fifth display area D. After that, a test print of the ink is performed in the area Rb outside that display area D. After performing a test print of ink in areas Ra and Rb, the coated film of the nozzle check pattern used for the test print is observed with an optical microscope to check the condition of nozzle N (whether or not it is clogged). If nozzle N is clogged, the coating head 110 is stopped and the clogged nozzle N is cleaned or the coating head 110 is replaced.

[0104] Subsequently, on the substrate surface on which the hole injection layer 1 is formed, a hole transport layer 2 is formed in each display area D by an inkjet method, similar to the method for forming the hole injection layer 1 described above.

[0105] Subsequently, after forming a resist pattern on the substrate surface on which the hole transport layer 2 is formed, for example, a solution (dispersion) containing nanoparticles in which the above-mentioned constituent materials are dissolved (dispersed) is applied, and by the lift-off method, a red light-emitting layer, a green light-emitting layer, and a blue light-emitting layer are sequentially formed to form the light-emitting layer 3 in each display area D.

[0106] Furthermore, on the substrate surface on which the light-emitting layer 3 is formed, an electron transport layer 4 is formed in each display area D by an inkjet method, similar to the method for forming the hole injection layer 1 described above, to form a QLED layer 36 (QLED layer formation step).

[0107] Subsequently, in the same manner as the manufacturing method of the first embodiment described above, the QLED display device 50 of this embodiment can be manufactured by forming a second electrode 37 in each display area D, thereby forming a QLED element layer 40 on each TFT layer 30, followed by a sealing film formation step and a piece formation step.

[0108] As described above, according to the manufacturing method of the QLED display device 50 of this embodiment, in the QLED layer formation step of the QLED element layer formation step, after test printing of ink in the region Ra outside the multiple display regions D on the resin substrate 100, the coating head 110 is moved continuously to sequentially form multiple QLED layers 36 (hole injection layer 1, hole transport layer 2, electron transport layer 4) for each of the multiple display regions D. Here, in the test printing of ink in region Ra, the state of each nozzle N of the coating head 110 before coating the first display region D can be checked, so that the occurrence of streaky unevenness and the like in the QLED layer 36 (hole injection layer 1, hole transport layer 2, electron transport layer 4) is suppressed and the film thickness of the QLED layer 36 can be made uniform.

[0109] Furthermore, according to the manufacturing method of the QLED display device 50 of this embodiment, in the QLED layer formation step of the QLED element layer formation step, after ejecting ink to each of the multiple display areas D, a test print of ink is performed in the area Rb outside each of the multiple display areas D. Here, the test print of ink in area Rb allows the state of each nozzle N of the coating head 110 after coating each display area D to be checked, so the quality of the QLED layer 36 (hole injection layer 1, hole transport layer 2, electron transport layer 4) coated using each nozzle N can be indirectly checked. Note that if the time between the test print of ink in the area Rb corresponding to the first to fourth display areas D and coating the next display area D is short, the test print of ink in area Rb allows the state of each nozzle N of the coating head 110 before coating the second and subsequent display areas D to be checked, and the occurrence of streaky unevenness in the QLED layer 36 (hole injection layer 1, hole transport layer 2, electron transport layer 4) can be further suppressed.

[0110] Furthermore, according to the manufacturing method of the QLED display device 50 of this embodiment, in the QLED layer formation step of the QLED element layer formation step, the coating head 110 is moved in directions 180 degrees different from each other in a pair of adjacent display areas D among a plurality of display areas D, and ink is ejected in the forward and return paths of the coating head 110 to form the QLED layer 36 (hole injection layer 1, hole transport layer 2, electron transport layer 4), thereby increasing the manufacturing efficiency of the QLED display device 50.

[0111] <Other Embodiments> In the embodiments described above, a method for manufacturing a display device in which coating is performed on both the forward and return paths of the coating head has been illustrated. However, the present invention can also be applied to a method for manufacturing a display device in which coating is performed on only one of the forward or return paths of the coating head.

[0112] Furthermore, while the above embodiments illustrate a method for manufacturing a display device in which an entire display area is coated with a single coating pass during the forward or return journey of the coating head, the present invention can also be applied to a method for manufacturing a display device in which an entire display area is coated with multiple coating passes during the forward and return journeys of the coating head.

[0113] Furthermore, while the above embodiments illustrate a display device in which the first electrode is the anode and the second electrode is the cathode, the present invention can also be applied to a display device in which the stacked structure of the QLED layer is reversed, with the first electrode being the cathode and the second electrode being the anode.

[0114] Furthermore, while the above embodiments illustrate a display device in which the electrode of a TFT electrically connected to the first electrode is used as the drain electrode, the present invention can also be applied to a display device in which the electrode of the TFT electrically connected to the first electrode is called the source electrode.

[0115] Furthermore, although the above embodiments described an example of a QLED display device, the present invention can be applied to a display device equipped with a plurality of light-emitting elements driven by electric current, for example, an organic electroluminescent display device equipped with OLEDs.

[0116] As described above, the present invention is useful for self-illuminating display devices.

[0117] D Display area N Nozzle P Subpixel 30 TFT layer (thin film transistor layer) 34 First electrode 36 QLED layer (quantum dot light-emitting diode layer, light-emitting functional layer) 37 Second electrode 40 QLED element layer (light-emitting element layer) 45 Encapsulation film 50 QLED display device 100 Resin substrate (base substrate) 110 Coating head

Claims

1. A method for manufacturing a display device, comprising: a thin-film transistor layer formation step of forming thin-film transistor layers in each of the multiple display areas defined on a base substrate; and a light-emitting element layer formation step of forming a light-emitting element layer on the thin-film transistor layer, in which a plurality of first electrodes, a plurality of light-emitting functional layers, and a common second electrode are sequentially stacked corresponding to a plurality of subpixels constituting the display area, wherein in the light-emitting element layer formation step, ink is ejected from a plurality of nozzles while moving a coating head having a plurality of nozzles to form the plurality of light-emitting functional layers by an inkjet method, wherein in the light-emitting functional layer formation step of forming the plurality of light-emitting functional layers, after performing a test print of the ink outside the plurality of display areas on the base substrate, the coating head is continuously moved to sequentially form the plurality of light-emitting functional layers for each of the plurality of display areas.

2. A method for manufacturing a display device according to claim 1, characterized in that, in the light-emitting functional layer forming step, after ejecting the ink to each of the plurality of display areas, a test print of the ink is performed outside each of the plurality of display areas, and before ejecting the ink to each of the second and subsequent plurality of display areas, a test print of the ink is performed outside each of the plurality of display areas.

3. A method for manufacturing a display device according to claim 1, characterized in that, in the light-emitting functional layer formation step, a test application of the ink is performed outside each of the multiple display areas before the ink is ejected to each of the second and subsequent display areas.

4. A method for manufacturing a display device according to claim 1, characterized in that, in the light-emitting functional layer forming step, after ejecting the ink to each of the plurality of display areas, a test print of the ink is performed outside each of the plurality of display areas.

5. A method for manufacturing a display device according to any one of claims 1 to 4, characterized in that, in the light-emitting functional layer forming step, the coating head is moved in directions that are 180 degrees different from each other in a pair of adjacent display areas among the plurality of display areas.

6. A method for manufacturing a display device according to claim 5, wherein the plurality of display areas are each provided in a rectangular shape in a plan view, and in the light-emitting functional layer forming step, the coating head is moved in the longitudinal direction of the display area while the ink is ejected.

7. A method for manufacturing a display device according to claim 6, wherein the plurality of display areas are arranged in a line along the shorter direction of the display area, and in the light-emitting functional layer forming step, the coating head is moved in the shorter direction of the plurality of display areas while the ink is not ejected.

8. A method for manufacturing a display device according to any one of claims 1 to 7, wherein the ink contains nanoparticles.

9. A method for manufacturing a display device according to any one of claims 1 to 8, characterized in that it comprises a sealing film formation step of forming a sealing film on the light-emitting layer after the light-emitting layer formation step.

10. A method for manufacturing a display device according to claim 9, characterized in that, after the sealing film forming step, the method further comprises a fragmentation step in which the base substrate and the layer formed on the base substrate are divided into individual pieces according to the display area.

11. A method for manufacturing a display device according to any one of claims 1 to 10, characterized in that at least one of the plurality of light-emitting functional layers is a quantum dot light-emitting diode layer.

Images