Display device

Abstract

Provided is a display device, wherein: in a light-emitting element layer, a plurality of first electrodes (31a), a common edge cover (32a), a plurality of light-emitting function layers, and a common second electrode are laminated in this order corresponding to a plurality of sub-pixels; the plurality of sub-pixels include a first sub-pixel (Pb), a second sub-pixel (Pr), and a third sub-pixel (Pg) that are adjacent to each other and emit different colors; the edge cover (32a) is provided so as to cover the peripheral end of each of the first electrodes (31a); each of the first electrodes (31a) exposed from the edge cover (32a) constitutes light-emitting regions (Lb, Lr, Lg); and the edge cover (32a) is provided so as to divide the light-emitting region (Lb) into a plurality of portions in the first sub-pixel (Pb).

Description

display device

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

[0002] In recent years, self-luminous display devices using light-emitting elements such as organic electroluminescence (EL) elements have been attracting attention as alternatives to liquid crystal display devices. In these self-luminous display devices, a plurality of thin film transistors (TFTs) are provided for each sub-pixel that constitutes a display area for displaying an image. In the display area of ​​the self-luminous display device, one pixel is formed by, for example, three adjacent sub-pixels P each having an area that emits red, green, and blue light, respectively.

[0003] For example, Patent Document 1 discloses an organic EL display device having a TFT layer in which a first planarization film and a second planarization film are stacked in this order on a first TFT, a second TFT, and a third TFT provided in each subpixel.

[0004] International Publication No. 2022 / 113333

[0005] In a self-luminous display device, as in Patent Document 1, the surface of the substrate on which the TFTs are formed is uneven, so in order to flatten the substrate surface in at least the display area, a planarization film made of, for example, an organic resin material is provided over the entire display area of ​​the substrate surface on which the TFTs are formed. However, if the surface of the planarization film is not sufficiently flat, variations occur in the film thickness of the light-emitting layer that constitutes the light-emitting element, resulting in uneven light emission, and there is room for improvement.

[0006] The present invention has been made in view of the above points, and an object of the present invention is to suppress uneven light emission within a pixel.

[0007] In order to achieve the above object, the display device of the present invention comprises a base substrate, a thin film transistor layer provided on the base substrate, and a light-emitting element layer provided on the thin film transistor layer, in which a plurality of first electrodes, a common edge cover, a plurality of light-emitting functional layers and a common second electrode are stacked in this order corresponding to a plurality of sub-pixels constituting a display area, wherein a planarization film is provided on the light-emitting element layer side of the thin film transistor layer, the plurality of sub-pixels have first sub-pixels, second sub-pixels and third sub-pixels that are adjacent to each other and emit different colors, the edge cover is provided so as to cover the peripheral edges of each of the first electrodes, and each of the first electrodes exposed from the edge cover constitutes a light-emitting area, and the edge cover is provided so as to divide the light-emitting area into a plurality of parts in the first sub-pixel.

[0008] According to the present invention, it is possible to suppress uneven light emission within a pixel.

[0009] FIG. 1 is a plan view showing a schematic configuration of an organic EL display device according to a first embodiment of the present invention. FIG. 2 is a plan view showing a schematic configuration of each pixel in a display region of the organic EL display device according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view of a display region of the organic EL display device according to the first embodiment of the present invention. FIG. 4 is an equivalent circuit diagram of a TFT layer constituting the organic EL display device according to the first embodiment of the present invention. FIG. 5 is a cross-sectional view showing an organic EL layer constituting the organic EL display device according to the first embodiment of the present invention. FIG. 6 is a plan view showing a schematic configuration of each pixel in a display region of an organic EL display device according to a second embodiment of the present invention.

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments.

[0011] First Embodiment FIGS. 1 to 5 show a first embodiment of a display device according to the present invention. In the following embodiments, an organic EL display device including an organic EL element layer is exemplified as a display device including a light-emitting element layer. FIG. 1 is a plan view showing a schematic configuration of an organic EL display device 50a according to this embodiment. FIG. 2 is a plan view showing a schematic configuration of each pixel Px in a display region D of the organic EL display device 50a. FIG. 3 is a cross-sectional view of the display region D of the organic EL display device 50a. FIG. 4 is an equivalent circuit diagram of a TFT layer 30 that constitutes the organic EL display device 50a. FIG. 5 is a cross-sectional view showing an organic EL layer 33 that constitutes the organic EL display device 50a.

[0012] 1, the organic EL display device 50a includes, for example, a rectangular display area D for displaying images, and a frame area F provided around the display area D. Note that, although the present embodiment illustrates a rectangular display area D, this rectangular shape also includes, for example, a substantially rectangular shape with arc-shaped sides, arc-shaped corners, or a shape with a notch in one of the sides.

[0013] A plurality of pixels Px (see FIG. 2 ) are arranged in a matrix in the display region D. Each pixel Px includes, for example, a first sub-pixel Pb having a plurality of blue light-emitting regions Lb that emit blue light to display blue, a second sub-pixel Pr having a plurality of red light-emitting regions Lr that emit red light to display red, and a third sub-pixel Pg having a plurality of green light-emitting regions Lg that emit green light to display green, arranged adjacent to each other, as shown in FIG. 2 . The blue light-emitting regions Lb, red light-emitting regions Lr, and green light-emitting regions Lg are each divided into a plurality of regions by edge covers 32 a (described later) in the first sub-pixel Pb, second sub-pixel Pr, and third sub-pixel Pg, as shown in FIG. 2 .

[0014] A terminal portion T is provided to extend in one direction (the Y direction in FIG. 1) at the end of the frame region F on the positive side in the X direction in FIG. 1. In addition, in the frame region F, as shown in FIG. 1, a folding portion B is provided between the display region D and the terminal portion T to extend in one direction (the Y direction in FIG. 1), and can be folded, for example, 180 degrees (in a U-shape) with the Y direction in the drawing as the folding axis.

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

[0016] The resin substrate 10 is made of an organic resin material such as polyimide resin.

[0017] 3, the TFT layer 30 includes a base coat film 11 provided on a resin substrate 10, a plurality of first TFTs 9a, a plurality of second TFTs 9b (see FIG. 4), a plurality of third TFTs 9c, and a plurality of capacitors 9d provided on the base coat film 11, and a protective insulating film 19, a first planarization film 20, and a second planarization film 22 provided in this order on each of the first TFTs 9a, each of the second TFTs 9b, each of the third TFTs 9c, and each of the capacitors 9d. That is, on the organic EL element layer 40 side of the TFT layer 30, a planarization film is provided that includes the first planarization film 20 provided on the resin substrate 10 side, and the second planarization film 22 stacked on the first planarization film 20 and provided on the organic EL element layer 40 side.

[0018] 3 , in the TFT layer 30, a base coat film 11, a semiconductor film that will become a semiconductor layer 12a (described later) and the like, a gate insulating film 13, a first metal film that will become a gate line 14g (described later) and the like, a first interlayer insulating film 15, a second metal film that will become an upper conductive layer 16c (described later) and the like, a second interlayer insulating film 17, a third metal film that will become a source line 18f (described later) and the like, a protective insulating film 19, a first planarizing film 20, a fourth metal film that will become a power line 21b (described later) and the like, and a second planarizing film 22 are laminated in this order on a resin substrate 10. Here, the base coat film 11, the gate insulating film 13, the first interlayer insulating film 15, the second interlayer insulating film 17, and the protective insulating film 19 are each composed of a single layer or a multilayer film of an inorganic insulating film such as a silicon nitride film, a silicon oxide film, or a silicon oxynitride film.

[0019] The TFT layer 30 is provided with, for example, a plurality of gate lines 14g extending parallel to one another in the Y direction in FIG. 1 . The TFT layer 30 is also provided with, for example, a plurality of light-emitting control lines 14e extending parallel to one another in the Y direction in FIG. 1 . Each light-emitting control line 14e is provided adjacent to each gate line 14g. The TFT layer 30 is also provided with, for example, a plurality of source lines 18f extending parallel to one another in the X direction in FIG. 1 . The TFT layer 30 is also provided with, for example, a plurality of power supply lines 21b arranged in a lattice pattern extending parallel to one another in the X and Y directions in FIG. 1 . The TFT layer 30 is also provided with, for example, a first TFT 9a, a second TFT 9b, a third TFT 9c, and a capacitor 9d in each subpixel (first subpixel Pb, second subpixel Pr, third subpixel Pg) as shown in FIG. 4 . Here, each gate line 14g and each light emission control line 14e are formed of the first metal film, each source line 18f is formed of the third metal film, and the power supply line 21b is formed of the fourth metal film.

[0020] As shown in Fig. 4, the first TFT 9a is electrically connected to the corresponding gate line 14g, source line 18f, and second TFT 9b in each subpixel (first subpixel Pb, second subpixel Pr, and third subpixel Pg). As shown in Fig. 3, the first TFT 9a includes 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 on a second interlayer insulating film 17. The semiconductor layer 12a and a semiconductor layer 12b (described later) are formed of a semiconductor film made of polysilicon such as low-temperature polysilicon (LTPS), and as shown in Fig. 3, the semiconductor layer 12a and a semiconductor layer 12b (described later) are provided on the base coat film 11 in an island-like shape. The semiconductor layer 12a and the semiconductor layer 12b include source and drain regions that are spaced apart from each other and a channel region that is defined between the source and drain regions. The gate electrode 14a is provided so as to overlap the channel region of the semiconductor layer 12a and is configured to control conduction between the source electrode 18a and the drain electrode 18b. The source electrode 18a and the drain electrode 18b are electrically connected to the source region and the drain region of the semiconductor layer 12a, respectively, through contact holes formed in the stacked film of the gate insulating film 13, the first interlayer insulating film 15, and the second interlayer insulating film 17, as shown in FIG.

[0021] 4, the second TFT 9b is electrically connected to the corresponding first TFT 9a, power supply line 21b, and third TFT 9c in each subpixel (first subpixel Pb, second subpixel Pr, and third subpixel Pg). The second TFT 9b has substantially the same structure as the first TFT 9a and a third TFT 9c (described later).

[0022] 4, in each subpixel (first subpixel Pb, second subpixel Pr, third subpixel Pg), the third TFT 9c is electrically connected to the corresponding second TFT 9b, a first electrode 31a of an organic EL element 35 (described later), and an emission control line 14e. As shown in FIG. 3, the third TFT 9c includes a semiconductor layer 12b provided on the base coat film 11, a gate electrode 14b provided on the semiconductor layer 12b with a gate insulating film 13 interposed therebetween, and a source electrode 18c and a drain electrode 18d provided spaced apart from each other on the second interlayer insulating film 17. The gate electrode 14b is provided to overlap a channel region of the semiconductor layer 12b and is configured to control conduction between the source electrode 18c and the drain electrode 18d. As shown in FIG. 3, the source electrode 18c and the drain electrode 18d are electrically connected to the source region and the drain region of the semiconductor layer 12b, respectively, through contact holes formed in the stacked film of the gate insulating film 13, the first interlayer insulating film 15, and the second interlayer insulating film 17.

[0023] In this embodiment, the first TFT 9 a, the second TFT 9 b, and the third TFT 9 c are illustrated as top-gate TFTs, but the first TFT 9 a, the second TFT 9 b, and the third TFT 9 c may be bottom-gate TFTs. In addition, in this embodiment, the first TFT 9 a, the second TFT 9 b, and the third TFT 9 c are illustrated as using polysilicon, but the first TFT 9 a, the second TFT 9 b, and the third TFT 9 c may be TFTs using an oxide semiconductor.

[0024] 4, in each subpixel (first subpixel Pb, second subpixel Pr, third subpixel Pg), the capacitor 9d is electrically connected to the corresponding first TFT 9a and power supply line 21b. As shown in FIG. 3, the capacitor 9d includes a lower conductive layer 14c formed of the first metal film, a first interlayer insulating film 15 provided to cover the lower conductive layer 14c, and an upper conductive layer 16c formed of the second metal film on the first interlayer insulating film 15 to overlap the lower conductive layer 14c. The upper conductive layer 16c is electrically connected to the power supply line 21b via a contact hole (not shown) formed in the second interlayer insulating film 17, the protective insulating film 19, and the first planarization film 20.

[0025] The first planarization film 20 and the second planarization film 22 have flat surfaces in the display region D and are made of, for example, an organic resin material such as polyimide resin or acrylic resin, or a polysiloxane-based SOG (spin on glass) material. As shown in FIG. 3 , a relay electrode 21 a and a power line 21 b formed from the fourth metal film are provided between the first planarization film 20 and the second planarization film 22. As shown in FIG. 3 , the relay electrode 21 a is electrically connected to the drain electrode 18 d of the third TFT 9 c through a first contact hole Ha formed in the laminated film of the protective insulating film 19 and the first planarization film 20. Furthermore, a recess Ra and a protrusion Rb are provided on the surface of the organic EL element layer 40 of the second planarization film 22 so as to overlap the first contact hole Ha and the power line 21 b, respectively.

[0026] 3, the organic EL element layer 40 includes a plurality of first electrodes 31a, a common edge cover 32a, a plurality of organic EL layers 33, and a common second electrode 34, which are stacked in order corresponding to a plurality of subpixels (first subpixel Pb, second subpixel Pr, third subpixel Pg). Here, in each of the subpixels (first subpixel Pb, second subpixel Pr, third subpixel Pg), the first electrode 31a, the organic EL layer 33, and the second electrode 34 constitute an organic EL element 35, as shown in FIG.

[0027] 3 , the first electrode 31a is electrically connected to the relay electrode 21a of each subpixel (first subpixel Pb, second subpixel Pr, third subpixel Pg) via a second contact hole Hb formed in the second planarization film 22. The first electrode 31a also has a function of injecting holes (positive holes) into the organic EL layer 33. In order to improve the efficiency of hole injection into the organic EL layer 33, the first electrode 31a is preferably formed from a material with a large work function. Here, examples of materials constituting the first electrode 31a include metal materials such as silver (Ag), aluminum (Al), vanadium (V), cobalt (Co), nickel (Ni), tungsten (W), gold (Au), titanium (Ti), ruthenium (Ru), manganese (Mn), indium (In), ytterbium (Yb), lithium fluoride (LiF), platinum (Pt), palladium (Pd), molybdenum (Mo), iridium (Ir), and tin (Sn). Examples of materials constituting the first electrode 31a include astatine (At) / astatine oxide (AtO ２ The first electrode 31a may be made of an alloy of tin oxide (SnO), zinc oxide (ZnO), indium tin oxide (ITO), indium zinc oxide (IZO), or another conductive oxide. The first electrode 31a may be formed by stacking multiple layers made of the above materials. Examples of compound materials with a large work function include indium tin oxide (ITO) and indium zinc oxide (IZO).

[0028] As shown in FIG. 2 , the edge cover 32 a is provided in a lattice pattern and is common to all subpixels P (first subpixel Pb, second subpixel Pr, and third subpixel Pg). Here, the edge cover 32 a is made of, for example, an organic resin material such as polyimide resin or acrylic resin, or a polysiloxane-based SOG material. While the present embodiment illustrates the edge cover 32 a made of an organic resin material or SOG material, the edge cover 32 a may be made of, for example, a single-layer or multilayer inorganic insulating film made of silicon nitride, silicon oxide, or silicon oxynitride. As shown in FIG. 3 , a portion of the surface of the edge cover 32 a protrudes upward in the drawing to form an island-shaped pixel photospacer. As shown in FIG. 2 , the edge cover 32 a covers the peripheral edge of the first electrode 31 a of each subpixel (first subpixel Pb, second subpixel Pr, and third subpixel Pg) and divides each of the blue light-emitting region Lb, red light-emitting region Lr, and green light-emitting region Lg into multiple regions. As shown in FIG. 3, the edge cover 32a is provided so as to overlap the recessed portion Ra, the protruding portion Rb, and the second contact hole Hb.

[0029] The organic EL layer 33 is provided as a light-emitting functional layer, and as shown in FIG. 5, includes a hole injection layer 1, a hole transport layer 2, a light-emitting layer 3, an electron transport layer 4, and an electron injection layer 5, which are stacked in this order on the first electrode 31 a.

[0030] The hole injection layer 1 is also called an anode buffer layer, and has the function of bringing the energy levels of the first electrode 31a and the organic EL layer 33 closer to each other, thereby improving the efficiency of hole injection from the first electrode 31a to the organic EL layer 33. Examples of materials that form the hole injection layer 1 include triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, phenylenediamine derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, and stilbene derivatives.

[0031] The hole transport layer 2 has a function of improving the efficiency of transporting holes from the first electrode 31a to the organic EL layer 33. Here, examples of materials constituting the hole transport layer 2 include 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.

[0032] The light-emitting layer 3 is a region into which holes and electrons are injected from the first electrode 31 a and the second electrode 34, respectively, and where the holes and electrons recombine when a voltage is applied by the first electrode 31 a and the second electrode 34. Here, the light-emitting layer 3 is made of a material with high luminous efficiency. Examples of materials that can be used to form the light-emitting layer 3 include metal oxinoid compounds [8-hydroxyquinoline metal complexes], naphthalene derivatives, anthracene derivatives, diphenylethylene derivatives, vinylacetone derivatives, triphenylamine derivatives, butadiene derivatives, coumarin derivatives, benzoxazole derivatives, oxadiazole derivatives, oxazole derivatives, benzimidazole derivatives, thiadiazole derivatives, benzothiazole derivatives, styryl derivatives, styrylamine derivatives, bisstyrylbenzene derivatives, trisstyrylbenzene derivatives, perylene derivatives, perinone derivatives, aminopyrene derivatives, pyridine derivatives, rhodamine derivatives, aquidin derivatives, phenoxazone, quinacridone derivatives, rubrene, poly-p-phenylenevinylene, and polysilane.

[0033] The electron transport layer 4 has a function of efficiently transferring electrons to the light-emitting layer 3. Examples of materials constituting the electron transport layer 4 include organic compounds such as oxadiazole derivatives, triazole derivatives, benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, tetracyanoanthraquinodimethane derivatives, diphenoquinone derivatives, fluorenone derivatives, silole derivatives, and metal oxinoid compounds.

[0034] The electron injection layer 5 has a function of bringing the energy levels of the second electrode 34 and the organic EL layer 33 closer to each other and improving the efficiency of electron injection from the second electrode 34 to the organic EL layer 33, and this function can reduce the driving voltage of the organic EL element 35. The electron injection layer 5 is also called a cathode buffer layer. Here, examples of materials constituting the electron injection layer 5 include lithium fluoride (LiF), magnesium fluoride (MgF ２ ), calcium fluoride (CaF ２ ), strontium fluoride (SrF ２ ), barium fluoride (BaF ２ inorganic alkali compounds such as aluminum oxide (Al ２ O ３ ), strontium oxide (SrO), etc.

[0035] As shown in FIG. 3 , the second electrode 34 is provided in common to all subpixels P (first subpixel Pb, second subpixel Pr, and third subpixel Pg) so as to cover each organic EL layer 33 and the edge cover 32 a. The second electrode 34 has a function of injecting electrons into the organic EL layer 33. To improve the efficiency of electron injection into the organic EL layer 33, the second electrode 34 is preferably made of a material with a small work function. Examples of materials that can be used for the second electrode 34 include silver (Ag), aluminum (Al), vanadium (V), calcium (Ca), titanium (Ti), yttrium (Y), sodium (Na), manganese (Mn), indium (In), magnesium (Mg), lithium (Li), ytterbium (Yb), and lithium fluoride (LiF). The second electrode 34 may be made of, for example, magnesium (Mg) / copper (Cu), magnesium (Mg) / silver (Ag), sodium (Na) / potassium (K), or astatine (At) / astatine oxide (AtO ２ The second electrode 34 may be formed of an alloy such as lithium (Li) / aluminum (Al), lithium (Li) / calcium (Ca) / aluminum (Al), or lithium fluoride (LiF) / calcium (Ca) / aluminum (Al). The second electrode 34 may be formed of a conductive oxide such as tin oxide (SnO), zinc oxide (ZnO), indium tin oxide (ITO), or indium zinc oxide (IZO). The second electrode 34 may be formed by stacking multiple layers made of the above materials. Examples of materials with a low work function include magnesium (Mg), lithium (Li), lithium fluoride (LiF), magnesium (Mg) / copper (Cu), magnesium (Mg) / silver (Ag), sodium (Na) / potassium (K), lithium (Li) / aluminum (Al), lithium (Li) / calcium (Ca) / aluminum (Al), and lithium fluoride (LiF) / calcium (Ca) / aluminum (Al).

[0036] 3 , the sealing film 45 is provided so as to cover the second electrode 34, and includes a first inorganic sealing film 41, an organic sealing film 42, and a second inorganic sealing film 43 laminated in this order on the second electrode 34, and has the function of protecting the organic EL layer 33 of the organic EL element 35 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 a silicon nitride film, a silicon oxide film, or a silicon oxynitride film. Moreover, the organic sealing film 42 is made of an organic resin material such as an acrylic resin, an epoxy resin, a silicone resin, a polyurea resin, a parylene resin, a polyimide resin, or a polyamide resin.

[0037] In the organic EL display device 50a having the above configuration, in each subpixel (first subpixel Pb, second subpixel Pr, third subpixel Pg), a gate signal is input to the first TFT 9a via the gate line 14g, turning the first TFT 9a on. A predetermined voltage corresponding to the source signal is written to the gate electrode of the second TFT 9b and the capacitor 9d via the source line 18f. When a light-emission control signal is input to the third TFT 9c via the light-emission control line 14e, the third TFT 9c turns on. A current corresponding to the gate voltage of the second TFT 9b is supplied from the power supply line 21b to the organic EL layer 33 of the organic EL element 35, causing the light-emitting layer 3 of the organic EL layer 33 to emit light, thereby displaying an image. In the organic EL display device 50a, even if the first TFT 9a is turned off, the gate voltage of the second TFT 9b is held by the capacitor 9d, so that light emission by the light-emitting layer 3 is maintained in each sub-pixel P until the gate signal for the next frame is input.

[0038] Next, an example of a method for manufacturing the organic EL display device 50a of this embodiment will be described. The method for manufacturing the organic EL display device 50a of this embodiment includes a TFT layer forming step, an organic EL element layer forming step, and a sealing film forming step.

[0039] <TFT layer formation process> First, a silicon nitride film (thickness: about 325 nm) and a silicon oxide film (thickness: about 50 nm) are sequentially formed on a resin substrate 10 formed on a glass substrate by, for example, a plasma CVD (Chemical Vapor Deposition) method, thereby forming a base coat film 11.

[0040] Next, an amorphous silicon film (about 50 nm thick) is formed on the substrate surface on which the base coat film 11 has been formed, for example, by plasma CVD, and the amorphous silicon film is crystallized by laser annealing or the like to form a semiconductor film made of polysilicon.Then, the semiconductor film is patterned to form the semiconductor layer 12a (12b) or the like.

[0041] Thereafter, a silicon oxide film (about 150 nm) is formed by, for example, plasma CVD on the surface of the substrate on which the semiconductor layer 12a (12b) and the like are formed, thereby forming the gate insulating film 13.

[0042] Furthermore, a molybdenum film (approximately 100 nm thick) is formed on the substrate surface on which the gate insulating film 13 is formed, for example, by sputtering, to form a first metal film, and then the first metal film is patterned to form the gate line 14 g, the light-emitting control line 14 e, the gate electrode 14 a (14 b), the lower conductive layer 14 c, etc. Note that the first metal film is not limited to the above, and may be formed from a metal material such as aluminum (Al), tungsten (W), tantalum (Ta), chromium (Cr), titanium (Ti), copper (Cu), etc. Furthermore, the first metal film may be formed not only as a single layer film of the above metal material including molybdenum (Mo), but also as a laminate film of these metal materials.

[0043] Next, by doping impurity ions into the semiconductor layer 12a (12b) using the gate electrode 14a (14b) as a mask, a part of the semiconductor layer 12a (12b) is made conductive, and a source region, a drain region, and a channel region are respectively formed in the semiconductor layer 12a (12b).

[0044] Thereafter, a silicon oxide film (about 200 nm thick) is formed by, for example, plasma CVD on the substrate surface where a portion of the semiconductor layer 12a (12b) has been made conductive, thereby forming a first interlayer insulating film 15.

[0045] Furthermore, a molybdenum film (approximately 100 nm thick) is formed by, for example, sputtering on the substrate surface on which the first interlayer insulating film 15 is formed, and then the second metal film is patterned to form the upper conductive layer 16c, etc. Note that the second metal film is not limited to the above, and may be formed from a metal material such as aluminum (Al), tungsten (W), tantalum (Ta), chromium (Cr), titanium (Ti), copper (Cu), etc. Also, the second metal film may be formed not only as a single layer film of the above metal material including molybdenum (Mo), but also as a laminate film of these metal materials.

[0046] Thereafter, a silicon oxide film (about 200 nm thick) is formed by, for example, plasma CVD on the substrate surface on which the upper conductive layer 16c and the like are formed, thereby forming the second interlayer insulating film 17.

[0047] Subsequently, the gate insulating film 13, the first interlayer insulating film 15 and the second interlayer insulating film 17 are patterned to form contact holes.

[0048] Thereafter, a titanium film (thickness: about 10 nm), an aluminum film (thickness: about 300 nm), and a titanium film (thickness: about 50 nm) are sequentially formed by, for example, sputtering on the surface of the substrate on which the contact holes have been formed, to form a third metal film, and then the third metal film is patterned to form a source line 18f, a source electrode 18a (18c), a drain electrode 18b (18d), etc.

[0049] Furthermore, a silicon oxide film (about 300 nm thick) is formed by, for example, plasma CVD on the surface of the substrate on which the source lines 18f and the like are formed, thereby forming the protective insulating film 19.

[0050] Next, a photosensitive acrylic resin (about 2.5 μm thick) is applied to the substrate surface on which the protective insulating film 19 has been formed, for example, by spin coating or slit coating, and then the applied film is pre-baked, exposed to light, developed, and post-baked to form a first planarization film 20 having a first contact hole Ha.

[0051] Thereafter, the protective insulating film 19 exposed from the first contact hole Ha in the first planarization film 20 is removed by etching, and the first contact hole Ha is formed in the protective insulating film 19 .

[0052] Furthermore, on the substrate surface where the first contact hole Ha has been formed in the protective insulating film 19, a titanium film (thickness: about 10 nm), an aluminum film (thickness: about 300 nm), and a titanium film (thickness: about 50 nm) are sequentially deposited by, for example, a sputtering method to form a fourth metal film, and then the fourth metal film is patterned to form the relay electrode 21 a, the power line 21 b, etc.

[0053] Finally, a photosensitive acrylic resin (about 2.5 μm thick) is applied to the substrate surface on which the relay electrodes 21 a etc. are formed, for example, by spin coating or slit coating, and then the applied film is pre-baked, exposed to light, developed and post-baked to form a second planarization film 22 having a second contact hole Hb.

[0054] In this manner, the TFT layer 30 can be formed.

[0055] <Organic EL element layer forming process> First, an ITO film (thickness: about 10 nm), an Ag film (thickness: about 100 nm), and an ITO film (thickness: about 10 nm) are formed in this order by, for example, a sputtering method on the second planarization film 22 of the TFT layer 30 formed in the TFT layer forming process to form a conductive laminated film, and then the conductive laminated film is patterned to form the first electrode 31 a.

[0056] Next, a photosensitive acrylic resin (approximately 2 μm thick) is applied to the substrate surface on which the first electrode 31 a is formed, for example, by spin coating or slit coating, and then the applied film is pre-baked, exposed to light, developed, and post-baked to form the edge cover 32 a.

[0057] Thereafter, a hole injection layer 1, a hole transport layer 2, a light-emitting layer 3, an electron transport layer 4, and an electron injection layer 5 are sequentially formed on the surface of the substrate on which the edge cover 32a is formed, for example, by vacuum deposition, to a thickness of approximately several tens of nm to 50 nm, thereby forming an organic EL layer 33.

[0058] Finally, an ITO film (about 100 nm thick) is formed by, for example, sputtering or vacuum deposition so as to cover the edge cover 32 a and each organic EL layer 33 , thereby forming the second electrode 34 .

[0059] In this manner, the organic EL element layer 40 can be formed.

[0060] <Sealing film forming process> First, an inorganic insulating film such as a silicon nitride film, a silicon oxide film, or a silicon oxynitride film is formed by plasma CVD using a mask on the surface of the substrate on which the organic EL element layer 40 formed in the organic EL element layer forming process is formed, thereby forming a first inorganic sealing film 41.

[0061] Subsequently, an organic resin material such as an acrylic resin is deposited by, for example, an inkjet method on the surface of the substrate on which the first inorganic sealing film 41 has been formed, to form an organic sealing film 42 .

[0062] Then, using a mask, an inorganic insulating film such as a silicon nitride film, a silicon oxide film, or a silicon oxynitride film is deposited by plasma CVD on the substrate surface on which the organic sealing film 42 has been formed, thereby forming a second inorganic sealing film 43, thereby forming a sealing film 45.

[0063] Finally, a protective sheet (not shown) is attached to the surface of the substrate on which the sealing film 45 is formed, and then laser light is irradiated from the glass substrate side of the resin substrate 10 to peel the glass substrate from the underside of the resin substrate 10, and a protective sheet (not shown) is attached to the underside of the resin substrate 10 from which the glass substrate has been peeled.

[0064] In this manner, the organic EL display device 50a can be manufactured.

[0065] As described above, in the organic EL display device 50a of this embodiment, in the first sub-pixel Pb, the second sub-pixel Pr, and the third sub-pixel Pg that constitute each pixel Px, the edge cover 32a not only covers the peripheral edge of the first electrode 31a but also divides the blue light-emitting region Lb, the red light-emitting region Lr, and the green light-emitting region Lg into a plurality of regions. Therefore, even if the surface of the second planarization film 22 is not sufficiently planarized and the film thickness of the light-emitting layer 3 of the organic EL element 35 varies, the blue light-emitting region Lb, the red light-emitting region Lr, and the green light-emitting region Lg are divided into a plurality of regions by the edge cover 32a in the first sub-pixel Pb, the second sub-pixel Pr, and the third sub-pixel Pg. Therefore, even if the film thickness of the light-emitting layer 3 of the organic EL element 35 varies, the uneven light emission caused by the variation in the film thickness of the light-emitting layer 3 in the first sub-pixel Pb, the second sub-pixel Pr, and the third sub-pixel Pg is not continuous, and the uneven light emission can be made less noticeable. This suppresses uneven light emission in the first subpixel Pb, the second subpixel Pr, and the third subpixel Pg, thereby suppressing uneven light emission within the pixel Px, which includes the first subpixel Pb, the second subpixel Pr, and the third subpixel Pg.

[0066] Second Embodiment Fig. 6 shows a second embodiment of a display device according to the present invention. Fig. 6 is a plan view showing a schematic configuration of each pixel Px in a display region D of an organic EL display device 50 of this embodiment. In the following embodiments, the same components as those in Figs. 1 to 5 are designated by the same reference numerals, and detailed description thereof will be omitted.

[0067] In the first embodiment described above, an organic EL display device 50a is exemplified in which the blue light-emitting region Lb, the red light-emitting region Lr, and the green light-emitting region Lg are divided into multiple regions in the first sub-pixel Pb, the second sub-pixel Pr, and the third sub-pixel Pg. However, in this embodiment, an organic EL display device 50b is exemplified in which the blue light-emitting region Lb is divided into multiple regions in the first sub-pixel Pb.

[0068] The organic EL display device 50b, like the organic EL display device 50a of the first embodiment described above, has, for example, a rectangular display area D for displaying images, and a frame area F provided around the display area D.

[0069] A plurality of pixels Px (see FIG. 6 ) are arranged in a matrix in the display region D. Each pixel Px includes, for example, a first sub-pixel Pb having a plurality of blue light-emitting regions Lb that emit blue light to display blue, a second sub-pixel Pr having a single red light-emitting region Lr that emits red light to display red, and a third sub-pixel Pg having a single green light-emitting region Lg that emits green light to display green, arranged adjacent to each other, as shown in FIG. 6 . The blue light-emitting region Lb in the first sub-pixel Pb is divided into a plurality of regions by edge covers 32 b (described later).

[0070] Similarly to the organic EL display device 50a of the first embodiment, the organic EL display device 50b includes a resin substrate 10 provided as a base substrate, a TFT layer 30 provided on the resin substrate 10, an organic EL element layer 40 provided as a light-emitting element layer on the TFT layer 30, and a sealing film 45 provided on the organic EL element layer 40.

[0071] The organic EL element layer 40 includes a plurality of first electrodes 31b, a common edge cover 32b, a plurality of organic EL layers 33, and a common second electrode 34 stacked in order to correspond to a plurality of subpixels (first subpixel Pb, second subpixel Pr, third subpixel Pg).

[0072] Similar to the first electrode 31a in the first embodiment, the first electrode 31b is electrically connected to the relay electrode 21a of each subpixel (first subpixel Pb, second subpixel Pr, third subpixel Pg) via a second contact hole Hb formed in the second planarization film 22. Similarly to the first electrode 31a in the first embodiment, the first electrode 31b has a function of injecting holes (positive holes) into the organic EL layer 33, and is preferably formed of a material with a large work function in order to improve the efficiency of hole injection into the organic EL layer 33. In the first embodiment, as shown in FIG. 2, the first electrode 31a is provided in a roughly rectangular shape with a protruding portion in the first subpixel Pb, the second subpixel Pr, and the third subpixel Pg. However, in the present embodiment, as shown in FIG. 6, the first electrode 31b is provided in a roughly rectangular shape with a protruding portion in the second subpixel Pr and the third subpixel Pg, and in the first subpixel Pb, the first electrode 31b is provided in a shape formed by connecting a pair of rectangular bodies at the corners.

[0073] As shown in FIG. 6 , the edge cover 32 b is provided in a lattice pattern and is common to all of the subpixels P (first subpixel Pb, second subpixel Pr, and third subpixel Pg). Here, the edge cover 32 b is made of, for example, an organic resin material such as polyimide resin or acrylic resin, or a polysiloxane-based SOG material. While the present embodiment illustrates the edge cover 32 b made of an organic resin material or SOG material, the edge cover 32 b may be made of, for example, a single-layer or multilayer inorganic insulating film made of silicon nitride, silicon oxide, silicon oxynitride, or the like, similar to the edge cover 32 a in the first embodiment. Furthermore, similar to the edge cover 32 a in the first embodiment, portions of the surface of the edge cover 32 b protrude upward to form island-shaped pixel photospacers. 2, the edge cover 32b is provided to cover the peripheral edge of the first electrode 31b of each subpixel (first subpixel Pb, second subpixel Pr, and third subpixel Pg) and to divide the blue light-emitting region Lb into multiple regions. Similarly to the edge cover 32a in the first embodiment, the edge cover 32b is provided to overlap the recessed portion Ra, the protruding portion Rb, and the second contact hole Hb.

[0074] The organic EL display device 50b having the above configuration is flexible, similar to the organic EL display device 50a of the first embodiment, and displays an image by appropriately causing the light-emitting layer 3 of the organic EL layer 33 to emit light in each sub-pixel P via the first TFT 9a, the second TFT 9b, and the third TFT 9c.

[0075] The organic EL display device 50b of this embodiment can be manufactured by changing the pattern shapes of the first electrode 31a and the edge cover 32a in the manufacturing method of the organic EL display device 50a of the first embodiment.

[0076] As described above, in the organic EL display device 50b of this embodiment, in the first sub-pixel Pb constituting each pixel Px, the edge cover 32b not only covers the peripheral edge of the first electrode 31b but also divides the blue light-emitting region Lb into multiple regions. Therefore, even if the surface of the second planarization film 22 is not sufficiently planarized and the thickness of the light-emitting layer 3 of the organic EL element 33 constituting the organic EL element 35 varies, in the first sub-pixel Pb, the blue light-emitting region Lb is divided into multiple regions by the edge cover 32b, so that the uneven light emission caused by the variation in the thickness of the light-emitting layer 3 in the first sub-pixel Pb is not continuous, making the uneven light emission less noticeable. Here, the first sub-pixel Pb, which emits blue light, has an area that is approximately twice as large as the second sub-pixel Pr, which emits red light, and the third sub-pixel Pg, which emits green light. Therefore, by dividing the blue light-emitting region Lb into multiple regions in the first sub-pixel Pb, uneven light emission can be effectively made less noticeable, and uneven light emission within the pixel Px, which includes the first sub-pixel Pb, the second sub-pixel Pr, and the third sub-pixel Pg, can be suppressed.

[0077] Other Embodiments In the above-described embodiments, the organic EL layer has a five-layer laminated structure including a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer. However, the organic EL layer may have a three-layer laminated structure including, for example, a hole injection layer / hole transport layer, a light-emitting layer, and an electron transport layer / electron injection layer.

[0078] In addition, in each of the above embodiments, an organic EL display device in which the first electrode is an anode and the second electrode is a cathode is exemplified, but the present invention can also be applied to an organic EL display device in which the layered structure of the organic EL layer is reversed, and the first electrode is a cathode and the second electrode is an anode.

[0079] Furthermore, in each of the above embodiments, an organic EL display device is exemplified in which the electrode of the TFT connected to the first electrode is used as the drain electrode, but the present invention can also be applied to an organic EL display device in which the electrode of the TFT connected to the first electrode is called the source electrode.

[0080] Furthermore, in each of the above embodiments, an organic EL display device has been described as an example of a display device. However, the present invention can be applied to a display device including a plurality of light-emitting elements driven by current, and can be applied to, for example, a display device including QLEDs (Quantum-dot light emitting diodes), which are light-emitting elements using a quantum dot-containing layer.

[0081] As described above, the present invention is useful for flexible display devices.

[0082] D Display area Ha First contact hole Hb Second contact hole Lb Blue light-emitting area Lr Red light-emitting area Lg Green light-emitting area Pb First sub-pixel Pr Second sub-pixel Pg Third sub-pixel Ra Concave portion Rb Convex portion 9a First TFT (thin film transistor) 9b Second TFT (thin film transistor) 9c Third TFT (thin film transistor) 10 Resin substrate (base substrate) 20 First planarization film 21a Relay electrode 21b Power supply line 22 Second planarization film 30 TFT layer (thin film transistor layer) 31a, 31b First electrode 32a, 32b Edge cover 33 Organic EL layer (organic electroluminescence layer, light-emitting function layer) 34 Second electrode 40 Organic EL element layer (light-emitting element layer) 45 Sealing film 50a, 50b Organic EL display device

Claims

1. A display device comprising: a base substrate; a thin film transistor layer provided on the base substrate; and a light emitting element layer provided on the thin film transistor layer, in which a plurality of first electrodes, a common edge cover, a plurality of light emitting functional layers and a common second electrode are laminated in this order corresponding to a plurality of sub-pixels constituting a display area, wherein a planarization film is provided on the light emitting element layer side of the thin film transistor layer, the plurality of sub-pixels are adjacent to each other and have first sub-pixels, second sub-pixels and third sub-pixels that emit different colors, the edge cover is provided to cover the peripheral ends of each of the first electrodes, and each of the first electrodes exposed from the edge cover constitutes a light emitting area, wherein the edge cover is provided in the first sub-pixel so as to divide the light emitting area into a plurality of areas.

2. The display device according to claim 1, wherein the first sub-pixel is configured to emit blue light.

3. The display device according to claim 2, wherein the edge covers are provided in the second sub-pixel and the third sub-pixel so as to divide the light-emitting region into a plurality of regions.

4. The display device according to claim 3, wherein the second sub-pixel and the third sub-pixel are configured to emit red and green light, respectively.

5. The display device according to any one of claims 1 to 4, wherein a recess is provided on the surface of the planarization film facing the light emitting element layer, and the edge cover is provided so as to overlap the recess.

6. A display device according to claim 5, wherein the planarization film comprises a first planarization film provided on the base substrate side and a second planarization film stacked on the first planarization film and provided on the light emitting element layer side; the thin film transistor layer comprises a plurality of thin film transistors provided in each of the sub-pixels; one of the plurality of thin film transistors is electrically connected to the corresponding first electrode in each of the sub-pixels via a first contact hole formed in the first planarization film, a relay electrode provided between the first planarization film and the second planarization film, and a second contact hole formed in the second planarization film; and the recess is provided so as to overlap the first contact hole.

7. The display device according to claim 6, wherein the edge cover is provided so as to overlap the second contact hole.

8. A display device according to any one of claims 1 to 4, characterized in that a convex portion is provided on the surface of the planarization film facing the light emitting element layer, and the edge cover is provided so as to overlap the convex portion.

9. A display device according to claim 8, characterized in that the planarization film comprises a first planarization film provided on the base substrate side and a second planarization film stacked on the first planarization film and provided on the light emitting element layer side, the thin film transistor layer comprises a power line provided between the first planarization film and the second planarization film, and the convex portion is provided so as to overlap the power line.

10. The display device according to any one of claims 1 to 9, further comprising a sealing film provided on the light emitting element layer.

11. The display device according to any one of claims 1 to 10, wherein each of the light-emitting functional layers is an organic electroluminescence layer.

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