Indication device

Abstract

This suppresses corrosion of the low-resistance conductive layer using a copper film in the TFT layer, which is electrically connected to the first electrode using a silver film. [Solution] A display device 50a comprising a base substrate 10, a thin-film transistor layer 30 provided on the base substrate 10 and having a low-resistance conductive layer 26a containing a copper film arranged corresponding to each of the multiple subpixels constituting a display area D, and a light-emitting element layer 40 provided on the thin-film transistor layer 30 and having a plurality of first electrodes E, a plurality of light-emitting functional layers 36 and a common second electrode 37 stacked in order corresponding to the plurality of subpixels, wherein each first electrode E containing a silver film is electrically connected to the low-resistance conductive layer 26a, and the low-resistance conductive layer 26a is covered with a first metal layer 27a having etching resistance to the etching solution of the silver film.

Description

Technical Field

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

Background Art

[0002] In recent years, as a display device replacing a liquid crystal display device, a self-emitting organic EL display device using an organic electroluminescence (hereinafter also referred to as "EL") element has been attracting attention. This organic EL display device includes, for example, a base substrate, a TFT layer provided on the base substrate and on which thin film transistors (hereinafter also referred to as "TFTs") are arranged, an organic EL element layer provided on the TFT layer and on which a plurality of organic EL elements are arranged corresponding to a plurality of sub-pixels constituting a display region, and a sealing film provided on the organic EL element layer. Here, the organic EL element includes, for example, a first electrode provided on the TFT layer, an organic EL layer provided on the first electrode, and a second electrode provided on the organic EL layer.

[0003] For example, Patent Document 1 discloses a display device including a light-emitting diode formed by laminating a transparent electrode, a light-emitting layer, and a reflective electrode in this order.

[0004] Further, Patent Document 2 discloses an organic EL display device in which a first metal layer containing a copper film is provided in the TFT layer, and a pixel electrode corresponding to the first electrode is formed by a second metal layer containing a silver film.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, in an organic EL display device, as described in Patent Document 2 above, in which a copper film with lower electrical resistance than an aluminum film is used for conductive layers such as wiring and electrodes in the TFT layer, and a silver film is used for the first electrode of the organic EL element layer, when the silver film is patterned by wet etching when forming the first electrode, there is a risk that the low-resistance conductive layer using the copper film of the TFT, which is electrically connected to the first electrode, will be corroded by the etching solution for the silver film.

[0007] The present invention has been made in view of the above, and its objective is to suppress corrosion of a low-resistance conductive layer using a copper film in a TFT layer electrically connected to a first electrode using a silver film. [Means for solving the problem]

[0008] To achieve the above objective, the present invention provides a display device comprising: a base substrate; a thin-film transistor layer provided on the base substrate, in which a low-resistance conductive layer containing a copper film is arranged corresponding to each of a plurality of subpixels constituting a display area; and a light-emitting layer provided 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 the plurality of subpixels, wherein each of the first electrodes contains a silver film and is electrically connected to the low-resistance conductive layer, and the low-resistance conductive layer is covered with a first metal layer having etching resistance to the silver film. [Effects of the Invention]

[0009] According to the present invention, corrosion of the low-resistance conductive layer using a copper film in the TFT layer, which is electrically connected to the first electrode using a silver film, can be suppressed. [Brief explanation of the drawing]

[0010] [Figure 1] This is a plan view showing a schematic configuration of an organic EL display device according to the first embodiment of the present invention. [Figure 2]This is a plan view of the display area of ​​an organic EL display device according to the first embodiment of the present invention. [Figure 3] This is a cross-sectional view of the display area of ​​an organic EL display device according to the first embodiment of the present invention. [Figure 4] This is a cross-sectional view of the terminal portion of an organic EL display device according to the first embodiment of the present invention. [Figure 5] This is an equivalent circuit diagram of the TFT layer constituting the organic EL display device according to the first embodiment of the present invention. [Figure 6] This is a cross-sectional view showing an organic EL layer constituting an organic EL display device according to the first embodiment of the present invention. [Figure 7] This is a cross-sectional view of the terminal portion of an organic EL display device according to a second embodiment of the present invention. [Figure 8] This is a cross-sectional view of the terminal portion of an organic EL display device according to a third embodiment of the present invention. [Modes for carrying out the invention]

[0011] 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.

[0012] 《First Embodiment》 Figures 1 to 6 show a first embodiment of the display device according to the present invention. Here, Figure 1 is a plan view showing the schematic configuration of the organic EL display device 50a of this embodiment. Figures 2 and 3 are a plan view and a cross-sectional view of the display area D of the organic EL display device 50a. Figure 4 is a cross-sectional view of the terminal portion T of the organic EL display device 50a. Figure 5 is an equivalent circuit diagram of the TFT layer 30 constituting the organic EL display device 50a. Figure 6 is a cross-sectional view showing the organic EL layer 36 constituting the organic EL display device 50a.

[0013] As shown in FIG. 1, the organic EL display device 50a includes, for example, a display area D for performing image display 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 illustrated, but this rectangular shape includes, for example, a substantially rectangular shape such as a shape with sides having an arc shape, a shape with corners having an arc shape, and a shape with a notch in a part of the side.

[0014] As shown in FIG. 2, in the display area D, a plurality of sub-pixels P are arranged in a matrix. Also, in the display area D, as shown in FIG. 2, for example, a sub-pixel P having a red light-emitting area Lr for performing red display, a sub-pixel P having a green light-emitting area Lg for performing green display, and a sub-pixel P having a blue light-emitting area Lb for performing blue display are provided adjacent to each other. In the display area D, for example, one pixel is constituted by three adjacent sub-pixels P having a red light-emitting area Lr, a green light-emitting area Lg, and a blue light-emitting area Lb.

[0015] At the positive-side end of the frame area F in the X direction in FIG. 1, a terminal portion T is provided so as to extend in one direction (Y direction in FIG. 1). Here, in the organic EL display device 50a, display wirings such as a gate line 19g, a light emission control line 19e, a source line 23f, and a power supply line 23g, which will be described later and are provided in the display area D, are drawn out toward the terminal portion T.

[0016] As shown in FIG. 3, the organic EL display device 50a includes a glass substrate 10 provided as a base substrate, a TFT layer 30 provided on the glass 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. \( \) \(

[0017] \) \( \) The glass substrate 10 is configured to have a thickness of about 0.1 mm to 0.5 mm, for example. \( \) \(

[0018] \) \( \)As shown in Figure 3, the TFT layer 30 comprises a plurality of first TFTs 9a (see Figure 5), a plurality of second TFTs 9b (see Figure 5), a plurality of third TFTs 9c, and a plurality of capacitors 9d provided on the glass substrate 10, and a protective insulating film 24a, a first planarization film 25a, and a second planarization film 28a provided sequentially on each of the first TFTs 9a, second TFTs 9b, third TFTs 9c, and capacitors 9d.

[0019] As shown in Figure 3, in the TFT layer 30, a first metal film which will become the first capacitive electrode 11c, etc., described later, a base insulating film (first inorganic insulating film) 12, a second metal film which will become the first gate electrode 13a, etc., described later, a first gate insulating film (second inorganic insulating film) 14, a semiconductor film which will become the semiconductor layer 15a, etc., described later, a second gate insulating film (third inorganic insulating film) 16a, a third metal film which will become the second gate electrode 19a, etc., described later, an interlayer insulating film (fourth inorganic insulating film) 20, a fourth metal film which will become the source electrode 23a, etc., described later, a protective insulating film (fifth inorganic insulating film) 24a, a first planarization film (first organic insulating film) 25a, a fifth metal film which will become the relay electrode 26a, etc., described later, a sixth metal film which will become the first metal layer 27a, etc., described later, and a second planarization film (second organic insulating film) 28a are stacked in order on the glass substrate 10. Here, the base insulating film 12, the first gate insulating film 14, the second gate insulating film 16a, the interlayer insulating film 20, and the protective insulating film 24a are composed of single-layer or multilayer films of inorganic insulating films such as silicon nitride, silicon oxide, or silicon oxynitride. The semiconductor layer 15a side of the first gate insulating film 14 and the semiconductor layer 15a side of the second gate insulating film 16a are composed of, for example, silicon oxide. The fifth metal film contains a copper film with low electrical resistance. The interlayer insulating film 20 may also be composed of, for example, the first interlayer insulating film and the second interlayer insulating film stacked in sequence.

[0020] In the TFT layer 30, as shown in Figure 2, multiple gate lines 19g are provided so as to extend parallel to each other in the X direction in the figure. Also in the TFT layer 30, as shown in Figure 2, multiple light emission control lines 19e are provided so as to extend parallel to each other in the X direction in the figure. Here, each light emission control line 19e is provided so as to be adjacent to each gate line 19g, as shown in Figure 2. Also in the TFT layer 30, as shown in Figure 2, multiple source lines 23f are provided so as to extend parallel to each other in the Y direction in the figure. Also in the TFT layer 30, as shown in Figure 2, multiple power lines 23g are provided so as to extend parallel to each other in the Y direction in the figure. Here, each power line 23g is provided so as to be adjacent to each source line 23f, as shown in Figure 2. Also in the TFT layer 30, as shown in Figure 5, a first TFT 9a, a second TFT 9b, a third TFT 9c, and a capacitor 9d are provided in each sub-pixel P. Here, each gate line 19g and each light emission control line 19e are formed of a third metal film, and each source line 23f and each power line 23g are formed of a fourth metal film.

[0021] As shown in Figure 5, the first TFT9a is electrically connected to the corresponding gate line 19g, source line 23f, and second TFT9b at each sub-pixel P. The first TFT9a has substantially the same structure as the third TFT9c, which will be described later.

[0022] As shown in Figure 5, the second TFT9b is electrically connected to the corresponding first TFT9a, power line 23g, and third TFT9c at each sub-pixel P. The second TFT9b has substantially the same structure as the third TFT9c, which will be described later.

[0023] As shown in Figure 5, the third TFT9c is electrically connected to the corresponding second TFT9b, the first electrode E constituting the organic EL element 39 (described later), and the light emission control line 19e at each subpixel P. Furthermore, as shown in Figure 3, the third TFT9c comprises a semiconductor layer 15a, a first gate electrode 13a provided on the glass substrate 10 side of the semiconductor layer 15a via a first gate insulating film 14, a second gate electrode 19a provided on the side of the semiconductor layer 15a opposite to the glass substrate 10 via a second gate insulating film 16a, and a source electrode 23a and a drain electrode 23b provided spaced apart from each other on the interlayer insulating film 20.

[0024] The semiconductor layer 15a is formed from a semiconductor film made of an oxide semiconductor such as an In-Ga-Zn-O system, and as shown in Figure 3, it comprises a source region 15aa and a drain region 15ab defined to be spaced apart from each other, and a channel region 15ac defined between the source region 15aa and the drain region 15ab. Here, the In-Ga-Zn-O system semiconductor is a ternary oxide of In (indium), Ga (gallium), and Zn (zinc), and the proportions (composition ratio) of In, Ga, and Zn are not particularly limited. The In-Ga-Zn-O system semiconductor may be amorphous or crystalline. As for the crystalline In-Ga-Zn-O system semiconductor, a crystalline In-Ga-Zn-O system semiconductor in which the c-axis is oriented generally perpendicular to the layer plane is preferred. In addition, other oxide semiconductors may be included instead of the In-Ga-Zn-O system semiconductor. Other oxide semiconductors may include, for example, In-Sn-Zn-O semiconductors (e.g., In2O3-SnO2-ZnO; InSnZnO). Here, the In-Sn-Zn-O semiconductor is a ternary oxide of In (indium), Sn (tin), and Zn (zinc). Other oxide semiconductors include In-Al-Zn-O semiconductors, In-Al-Sn-Zn-O semiconductors, Zn-O semiconductors, In-Zn-O semiconductors, Zn-Ti-O semiconductors, Cd-Ge-O semiconductors, Cd-Pb-O semiconductors, CdO (cadmium oxide), Mg-Zn-O semiconductors, In-Ga-Sn-O semiconductors, In-Ga-O semiconductors, Zr-In-Zn-O semiconductors, Hf-In-Zn-O semiconductors, Al-Ga-Zn-O semiconductors, Ga-Zn-O semiconductors, In-Ga-Zn-Sn-O semiconductors, InGaO3(ZnO)5, and magnesium zinc oxide (Mg x Zn 1-x O), cadmium zinc oxide (Cd x Zn 1-x It may also contain elements such as ZnO. Furthermore, as the Zn-O semiconductor, amorphous, polycrystalline, microcrystalline, or unimpeded ZnO can be used, with one or more impurity elements from Group 1, Group 13, Group 14, Group 15, and Group 17 added.

[0025] As shown in Figure 3, the first gate electrode 13a is provided so as to overlap the semiconductor layer 15a and is configured to control characteristics such as the S value (turn-up coefficient in the subthresh region) of the third TFT 9c. Here, as shown in Figure 3, the first gate electrode 13a is electrically connected to the wiring layer 23e via contact holes formed in the first gate insulating film 14 and the interlayer insulating film 20. The wiring layer 23e, source electrode 23a, drain electrode 23b, the wiring layer 23c (described later), the first wiring layer 23d, and the second terminal layer 23t are formed from a fourth metal film, similar to the source wire 23f, etc.

[0026] As shown in Figure 3, the second gate electrode 19a is provided so as to overlap the channel region 15ac of the semiconductor layer 15a and is configured to control the conductivity between the source region 15aa and the drain region 15ab of the semiconductor layer 15a. Here, as shown in Figure 3, the second gate electrode 19a is electrically connected to the wiring layer 23c via a contact hole formed in the interlayer insulating film 20. The second gate electrode 19a is formed of a third metal film, similar to the gate wire 19g, etc.

[0027] As shown in Figure 3, the source electrode 23a and the drain electrode 23b are electrically connected to the source region 15aa and the drain region 15ab of the semiconductor layer 15a, respectively, via contact holes formed in the interlayer insulating film 20. Here, as shown in Figure 3, the drain electrode 23b is electrically connected to the relay electrode 26a formed of the fifth metal film via contact holes formed in the protective insulating film 24a and the first planarization film 25a. The relay electrode 26a is provided as a low-resistance conductive layer and is covered by the first metal layer 27a formed of the sixth metal film, as shown in Figure 3. The sixth metal film is formed of a titanium film or titanium alloy film that has resistance to etching solutions (e.g., a mixture of phosphoric acid, nitric acid, and acetic acid) for the silver film constituting the first electrode E.

[0028] In this embodiment, the first TFT9a, second TFT9b, and third TFT9c are exemplified as double-gate type, but the first TFT9a, second TFT9b, and third TFT9c may be top-gate type or bottom-gate type. Also, in this embodiment, the first TFT9a, second TFT9b, and third TFT9c are exemplified as having a semiconductor layer 15a made of an oxide semiconductor, but the semiconductor layer 15a may be made of polysilicon such as LTPS (low temperature polysilicon). 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.

[0029] As shown in Figure 5, the capacitor 9d is electrically connected to the corresponding first TFT 9a and power line 23g in each sub-pixel P. Furthermore, as shown in Figure 3, the capacitor 9d comprises a first capacitance electrode 11c formed of a first metal film, a second capacitance electrode 13b formed of a second metal film, and a base insulating film 12 provided between the first capacitance electrode 11c and the second capacitance electrode 13b. Here, as shown in Figure 3, the second capacitance electrode 13b is electrically connected to the first wiring layer 23d formed of a fourth metal film via contact holes formed in the first gate insulating film 14 and the interlayer insulating film 20. Furthermore, as shown in Figure 3, the first wiring layer 23d is electrically connected to the second wiring layer 26b formed of a fifth metal film via contact holes formed in the protective insulating film 24a and the first planarization film 25a. In addition, as shown in Figure 3, the second wiring layer 26b is covered by a second metal layer 27b formed of a sixth metal film. The first wiring layer 23d is electrically connected to the power line 23g.

[0030] The first planarization film 25a and the second planarization film 28a have a flat surface in the display area D and are composed of, for example, an organic resin material such as polyimide resin or acrylic resin, or a polysiloxane-based SOG (spin on glass) material.

[0031] As shown in Figure 3, the organic EL element layer 40 comprises a plurality of first electrodes E, a plurality of organic EL layers 36, and a common second electrode 37, which are stacked sequentially to correspond to a plurality of subpixels P. Here, in each subpixel P, the first electrode E, the organic EL layer 36, and the second electrode 37 constitute an organic EL element 39, as shown in Figure 3, and in the organic EL element layer 40, the plurality of organic EL elements 39 provided to correspond to the plurality of subpixels P are arranged in a matrix.

[0032] Multiple first electrodes E are arranged in a matrix on the second planarization film 28a to correspond to multiple subpixels P. Furthermore, as shown in Figure 3, the first electrodes E are electrically connected to the drain electrodes 23b of each third TFT 9c via contact holes formed in the second planarization film 28a, the first metal layer 27a, the relay electrode 26a, and contact holes formed in the first planarization film 25a and the protective insulating film 24a. In addition, as shown in Figure 3, the first electrodes E include a reflective electrode R provided on the second planarization film 28a and a transparent electrode 34a provided on the reflective electrode R.

[0033] As shown in Figure 3, the reflective electrode R comprises a transparent conductive layer 31a provided on the second planarization film 28a and a metal layer 32a provided on the transparent conductive layer 31a. Here, the peripheral edge of the reflective electrode R is covered by a first edge cover 33a provided in a grid pattern over the entire display area D, as shown in Figure 3. The first edge cover 33a is made of an inorganic insulating film, such as a single-layer or multi-layer film of silicon nitride, silicon oxide, or silicon oxynitride.

[0034] The transparent conductive layer 31a is formed of a transparent conductive film such as an indium tin oxide (ITO) film and has light transmittance.

[0035] The metal layer 32a is formed of a metal film such as a silver film or a silver alloy film, and has light reflectivity.

[0036] The transparent electrode 34a has the function of injecting holes into the organic EL layer 36. Furthermore, in order to improve the hole injection efficiency into the organic EL layer 36, it is more preferable to form the transparent electrode 34a from a material with a large work function. Here, the transparent electrode 34a is formed from a transparent conductive film such as an ITO film and has light transmittance. The peripheral edge of the transparent electrode 34a is covered by a second edge cover 35a which is provided in a grid pattern over the entire display area D, as shown in Figure 3. The second edge cover 35a is made of an inorganic insulating film such as a single layer or multilayer film of silicon nitride, silicon oxide, or silicon oxynitride.

[0037] The organic EL layer 36 is provided as a light-emitting functional layer and, as shown in Figure 6, comprises 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 sequentially stacked on the transparent electrode 34a. In this embodiment, a configuration in which each of the multiple light-emitting functional layers is an organic EL layer 36 is illustrated, but at least one of the multiple light-emitting functional layers may be an organic EL layer 36.

[0038] The hole injection layer 1, also called the anode buffer layer, has the function of bringing the energy levels of the transparent electrode 34a and the organic EL layer 36 closer together, thereby improving the hole injection efficiency from the transparent electrode 34a to the organic EL layer 36. Examples of materials that constitute the hole injection layer 1 include polyarylalkane derivatives, pyrazoline derivatives, phenylenediamine derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, and stilbene derivatives.

[0039] The hole transport layer 2 has the function of improving the efficiency of hole transport from the transparent electrode 34a to the organic EL layer 36. Examples of materials constituting the hole transport layer 2 include triphenylamine derivatives, porphyrin derivatives, aromatic tertiary amine compounds, styrylamine derivatives, polyvinylcarbazole, poly-p-phenylenevinylene, polysilane, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amine-substituted chalcone derivatives, fluorenone derivatives, hydrazone derivatives, hydrogenated amorphous silicon, hydrogenated amorphous silicon carbide, zinc sulfide, zinc selenide, and the like.

[0040] The light-emitting layer 3 is a region in which holes and electrons are injected from the transparent electrode 34a and the second electrode 37, respectively, when a voltage is applied by the transparent electrode 34a and the second electrode 37, and where holes and electrons recombine. Here, the light-emitting layer 3 is formed of a material with high luminescence efficiency. Examples of materials constituting the light-emitting layer 3 include metal oxynoide compounds [8-hydroxyquinoline metal complex], naphthalene derivatives, anthracene derivatives, diphenylethylene derivatives, vinylacetone 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.

[0041] The electron transport layer 4 has the function of efficiently transporting electrons to the light-emitting layer 3. Examples of materials that make up the electron transport layer 4 include imidazole derivatives, oxadiazole derivatives, triazole derivatives, benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, tetracyanoanthraquinodimethane derivatives, diphenoquinone derivatives, fluorenone derivatives, silole derivatives, and metal oxynoide compounds.

[0042] The electron injection layer 5 has the function of bringing the energy levels of the second electrode 37 and the organic EL layer 36 closer together, thereby improving the efficiency of electron injection from the second electrode 37 to the organic EL layer 36. This function allows the driving voltage of the organic EL element 39 to be lowered. The electron injection layer 5 is also called the cathode buffer layer. Examples of materials that make up the electron injection layer 5 include inorganic alkali compounds such as lithium fluoride (LiF), magnesium fluoride (MgF2), calcium fluoride (CaF2), strontium fluoride (SrF2), and barium fluoride (BaF2), as well as aluminum oxide (Al2O3) and strontium oxide (SrO).

[0043] The second electrode 37 is provided on multiple organic EL layers 36 so as to be common to multiple subpixels P, that is, as shown in Figure 3, so as to cover each organic EL layer 36 and the second edge cover 35a. The second electrode 37 also has the function of injecting electrons into the organic EL layer 36. Furthermore, to improve the electron injection efficiency into the organic EL layer 36, it is more preferable that the second electrode 37 be made of a material with a small work function. Here, the second electrode 37 is formed of, for example, a transparent conductive film such as an ITO film or an IZO film, or an ultrathin metal film such as an MgAg film, and has light transmittance.

[0044] 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 stacked on the second electrode 37, and has the function of protecting the organic EL layer 36 of the organic EL element 39 from moisture and oxygen.

[0045] The first inorganic sealing film 41 and the second inorganic sealing film 43 are composed of an inorganic insulating film such as a silicon nitride film, a silicon oxide film, or a silicon oxynitride film.

[0046] The organic encapsulation film 42 is composed of an organic resin material such as acrylic resin, epoxy resin, silicone resin, polyurea resin, parylene resin, polyimide resin, or polyamide resin.

[0047] Furthermore, the organic EL display device 50a includes a plurality of first terminal layers 26t (see Figure 4) formed of a fifth metal film, which are provided along the direction in which the terminal portion T extends (Y direction in Figure 1) in the terminal portion T of the frame region F. Here, as shown in Figure 4, the terminal portion T is provided with a second planarization film 28a instead of a first planarization film 25a.

[0048] As shown in Figure 4, the first terminal layer 26t is covered by a third metal layer 27t formed of a sixth metal film. Furthermore, as shown in Figure 4, the first terminal layer 26t is electrically connected to a second terminal layer 23t formed of a fourth metal film via contact holes formed in the protective insulating film 24a. Here, the second terminal layer 23t is electrically connected to a third terminal layer 11t formed of a first metal film via contact holes formed in the interlayer insulating film 20, the first gate insulating film 14, and the base insulating film 12. Also, as shown in Figure 4, the third metal layer 27t is electrically connected to a fourth terminal layer 34b formed in the same layer as the transparent electrode 34a using the same material, via contact holes formed in the second planarization film 28a and the first edge cover 33a. The peripheral edge of the fourth terminal layer 34b is covered by a second edge cover 35a, as shown in Figure 4. Furthermore, the third terminal layer 11t is electrically connected to indicator wiring such as the gate line 19g, the light emission control line 19e, the source line 23f, and the power line 23g.

[0049] In the organic EL display device 50a with the above structure, in each sub-pixel P, when a gate signal is input to the first TFT 9a via the gate line 19g, the first TFT 9a is turned on, and 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 23f. When a light emission control signal is input to the third TFT 9c via the light emission control line 19e, the third TFT 9c is turned on, and a current corresponding to the gate voltage of the second TFT 9b is supplied from the power line 23g to the organic EL layer 36 of the organic EL element 39. As a result, the light emitting layer 3 of the organic EL layer 36 emits light, and image display is performed. In the organic EL display device 50a, even when the first TFT 9a is turned off, the gate voltage of the second TFT 9b is held by the capacitor 9d, so that the light emission by the light emitting layer 3 is maintained in each sub-pixel P until the gate signal of the next frame is input.

[0050] Next, a method for manufacturing the organic EL display device 50a of the present embodiment will be described. The method for manufacturing the organic EL display device 50a of the present embodiment includes a TFT layer forming step, an organic EL element layer forming step, and a sealing film forming step.

[0051] <TFT layer forming step> First, on the glass substrate 10, for example, a copper film (about 300 nm thick) or the like is formed by sputtering to form a first metal film. Then, the first metal film is patterned to form the first capacitive electrode 11c, the third terminal layer 11t, and the like.

[0052] Subsequently, on the substrate surface where the first capacitive electrode 11c and the like are formed, for example, a silicon nitride film (about 150 nm thick) or the like is formed by plasma CVD (Chemical Vapor Deposition) to form a base insulating film 12 as the first inorganic insulating film.

[0053] Subsequently, a second metal film is formed on the substrate surface on which the base insulating film 12 is formed, for example by sputtering, by depositing a copper film (approximately 300 nm thick). After that, the second metal film is patterned to form the first gate electrode 13a, the second capacitive electrode 13b, and the like.

[0054] Furthermore, a first gate insulating film 14 is formed as a second inorganic insulating film by sequentially depositing a silicon nitride film (approximately 100 nm thick) and a silicon oxide film (approximately 200 nm thick) on the substrate surface on which the first gate electrode 13a etc. are formed, for example by plasma CVD.

[0055] Next, a semiconductor film (approximately 50 nm thick) such as InGaZnO4 is deposited on the substrate surface on which the first gate insulating film 14 is formed, for example by sputtering, and then a semiconductor layer 15a is formed by patterning the semiconductor film.

[0056] Subsequently, a silicon oxide film (approximately 200 nm thick) is deposited on the substrate surface on which the semiconductor layer 15a, etc., is formed, for example by plasma CVD. Then, a copper film (approximately 300 nm thick) is deposited by sputtering to form a third metal film. After that, these laminated films are patterned to form a second gate insulating film 16a as a third inorganic insulating film, and also to form a second gate electrode 19a, gate line 19g, light emission control line 19e, etc.

[0057] Furthermore, on the substrate surface on which the second gate insulating film 16a etc. are formed, for example, a silicon oxide film (approximately 300 nm thick) and a silicon nitride film (approximately 200 nm thick) are sequentially deposited by plasma CVD, and then the laminated films, the first gate insulating film 14 and the base insulating film 12 are patterned to form contact holes, thereby forming an interlayer insulating film 20 as a fourth inorganic insulating film. During the heat treatment when forming the interlayer insulating film 20, a portion of the semiconductor layer 15a is made conductive, and a source region 15ac, a drain region 15ab and a channel region 15ac are formed in the semiconductor layer 15a.

[0058] Next, a copper film (approximately 300 nm thick) is deposited on the substrate surface on which the interlayer insulating film 20 is formed, for example by sputtering, to form a fourth metal film. Then, the fourth metal film is patterned to form source wires 23f, power lines 23g, source electrodes 23a, drain electrodes 23b, wiring layers 23c, first wiring layers 23d, wiring layers 23e, and second terminal layers 23t, etc.

[0059] Subsequently, a silicon oxide film (approximately 150 nm thick) and a silicon nitride film (approximately 100 nm thick) are sequentially deposited on the substrate surface on which the source line 23f etc. are formed, for example by plasma CVD, to form a fifth inorganic insulating film. Then, a polyimide-based photosensitive resin film (approximately 2 μm thick) is applied, for example by spin coating or slit coating, and then pre-baking, exposure, development, and post-baking are performed on the photosensitive resin film to form a first planarization film 25a. The fifth inorganic insulating film exposed from the first planarization film 25a is then etched to form a protective insulating film 24a.

[0060] Furthermore, on the substrate surface on which the protective insulating film 24a is formed, an ITO film (approximately 50 nm thick) and a copper film (approximately 300 nm thick) are sequentially deposited by, for example, a sputtering method to form a laminated conductive film of the ITO film and the copper film (fifth metal film). After that, the laminated conductive film is patterned to form the relay electrode 26a, the second wiring layer 26b, the first terminal layer 26t, and so on.

[0061] Next, a titanium film (approximately 30 nm to 70 nm thick) is deposited on the substrate surface on which the relay electrode 26a, etc., is formed, for example by sputtering, to form a sixth metal film. Then, the sixth metal film is patterned to form the first metal layer 27a, the second metal layer 27b, the third metal layer 27t, etc.

[0062] Finally, a polyimide-based photosensitive resin film (approximately 2 μm thick) is applied to the substrate surface on which the first metal layer 27a is formed, for example, by a spin coating method or a slit coating method. Then, the second planarization film 28a is formed by pre-baking, exposure, development, and post-baking of the photosensitive resin film.

[0063] <Organic EL element layer formation process> First, on the second planarization film 28a formed in the TFT layer formation process described above, an ITO film (approximately 50 nm thick) and a silver film (approximately 100 nm thick) are sequentially deposited, for example, by sputtering. Then, these laminated films are patterned by wet etching with a mixture of phosphoric acid, nitric acid, and acetic acid, for example, to form a reflective electrode R consisting of a transparent conductive layer 31a and a metal layer 32a.

[0064] Next, an inorganic insulating film, such as a silicon nitride film (approximately 100 nm thick), is deposited on the substrate surface on which the reflective electrode R and the like are formed, for example, by plasma CVD. After that, the inorganic insulating film is patterned to form the first edge cover 33a.

[0065] Subsequently, an ITO film (approximately 100 nm thick) is deposited on the substrate surface on which the first edge cover 33a, etc., is formed, for example by sputtering. Then, the ITO film is patterned, for example by wet etching with oxalic acid, to form the transparent electrode 34a and the fourth terminal layer 34b.

[0066] Furthermore, a silicon nitride film (approximately 250 nm thick) is formed on the substrate surface on which the transparent electrode 34a is formed, for example, by plasma CVD, and then the silicon nitride film is patterned to form the second edge cover 35a.

[0067] Next, on the substrate surface on which the second edge cover 35a is formed, 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 deposited to a thickness of several tens to 50 nm, for example, by vacuum deposition, to form an organic EL layer 36.

[0068] Finally, a transparent conductive film, such as an ITO film (approximately 100 nm thick), is deposited on the substrate surface on which the organic EL layer 36 is formed by sputtering using a film deposition mask to form the second electrode 37.

[0069] In this manner, the organic EL element layer 40 can be formed.

[0070] <Sealing 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 organic EL element layer 40 formed in the above organic EL element layer formation step is formed, using a film formation mask and plasma CVD to form a first inorganic encapsulation film 41.

[0071] 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.

[0072] Finally, an inorganic insulating film, such as a silicon nitride film, silicon oxide film, or silicon oxynitride film, is deposited on the substrate surface on which the organic encapsulation film 42 is formed, using a deposition mask and plasma CVD to form a second inorganic encapsulation film 43, thereby forming the encapsulation film 45.

[0073] In this manner, the organic EL display device 50a can be manufactured.

[0074] As described above, in the organic EL display device 50a of this embodiment, in each subpixel P, the intermediate electrode 26a, which is arranged in the TFT layer 30 as a low-resistance conductive layer including a copper film and electrically connected to the first electrode E including a silver film of the organic EL element layer 40, is covered with a first metal layer 27a formed of a titanium film or titanium alloy film. Therefore, even if the laminated film of the ITO film and silver film is patterned by wet etching with a mixture of phosphoric acid, nitric acid, and acetic acid to form the reflective electrode R of the first electrode E, the etching solution is blocked by the first metal layer 27a and does not easily penetrate the intermediate electrode 26a. As a result, the copper film of the intermediate electrode 26a can be protected from the etching solution, and corrosion of the intermediate electrode 26a using the copper film of the TFT layer 30, which is electrically connected to the first electrode E using the silver film, can be suppressed.

[0075] Furthermore, according to the organic EL display device 50a of this embodiment, since no inorganic insulating film is placed between the relay electrode 26a and the reflective electrode R, it becomes easier to control the inclination of the inner surface of the contact hole formed in the second planarization film 28a, thereby easily ensuring electrical connection between the relay electrode 26a and the reflective electrode R.

[0076] 《Second Embodiment》 Figure 7 shows a second embodiment of the display device according to the present invention. Here, Figure 7 is a cross-sectional view of the terminal portion T of the organic EL display device 50b of this embodiment. In the following embodiments, the same reference numerals are used for parts that are the same as those in Figures 1 to 6, and their detailed descriptions are omitted.

[0077] In the first embodiment described above, an organic EL display device 50a was illustrated in which the second planarization film 28a of the display area D is also provided on the terminal portion T. However, in this embodiment, an organic EL display device 50b is illustrated in which a second planarization film 28b, which is thinner than the second planarization film 28a of the display area D, is provided on the terminal portion T.

[0078] The organic EL display device 50b, like the organic EL display device 50a of the first embodiment, includes, for example, a display area D for displaying an image, provided in a rectangular shape, and a frame area F provided in a frame shape around the display area D and having a terminal portion T. Furthermore, the organic EL display device 50b, like the organic EL display device 50a of the first embodiment, includes a glass substrate 10 provided as a base substrate, a TFT layer 30 provided on the glass substrate 10, an organic EL element layer 40 provided on the TFT layer 30 as a light-emitting element layer, and a sealing film 45 provided on the organic EL element layer 40. Here, since the configuration of the display area D of the organic EL display device 50b is substantially the same as that of the organic EL display device 50a of the first embodiment, this embodiment will focus on describing the configuration of the terminal portion T of the organic EL display device 50b.

[0079] The organic EL display device 50b, like the organic EL display device 50a of the first embodiment described above, is provided in the terminal portion T of the frame region F with a plurality of first terminal layers 26t (see Figure 7) formed of a fifth metal film and provided along the direction in which the terminal portion T extends. Here, in the terminal portion T, as shown in Figure 7, a second planarization film 28b is provided instead of the second planarization film 28a (see Figure 4) of the first embodiment described above. The thickness of the second planarization film 28b is, for example, about 1 μm, which is thinner than the thickness of the second planarization film 28a provided in the display region D (about 2 μm). The other configurations of the terminal portion T of the organic EL display device 50b are substantially the same as those of the terminal portion of the organic EL display device 50a of the first embodiment described above.

[0080] In the organic EL display device 50b with the above configuration, similar to the organic EL display device 50a of the first embodiment, an image is displayed in each subpixel P by appropriately emitting light from the light-emitting layer 3 of the organic EL layer 36 of the organic EL element 39 via the first TFT 9a, second TFT 9b, and third TFT 9c.

[0081] The organic EL display device 50b of this embodiment can be manufactured by, in the manufacturing method of the organic EL display device 50a of the first embodiment, by exposing the photosensitive resin film when forming the second planarization film 28a using, for example, a halftone mask.

[0082] As described above, in the organic EL display device 50b of this embodiment, in each subpixel P, the intermediate electrode 26a, which is arranged in the TFT layer 30 as a low-resistance conductive layer including a copper film and electrically connected to the first electrode E including a silver film of the organic EL element layer 40, is covered with a first metal layer 27a formed of a titanium film or a titanium alloy film. Therefore, even if the laminated film of the ITO film and silver film is patterned by wet etching with a mixture of phosphoric acid, nitric acid, and acetic acid to form the reflective electrode R of the first electrode E, the etching solution is blocked by the first metal layer 27a and does not easily penetrate the intermediate electrode 26a. As a result, the copper film of the intermediate electrode 26a can be protected from the etching solution, and corrosion of the intermediate electrode 26a using the copper film of the TFT layer 30, which is electrically connected to the first electrode E using the silver film, can be suppressed.

[0083] Furthermore, according to the organic EL display device 50b of this embodiment, since no inorganic insulating film is placed between the relay electrode 26a and the reflective electrode R, it becomes easier to control the inclination of the inner surface of the contact hole formed in the second planarization film 28a, thereby easily ensuring electrical connection between the relay electrode 26a and the reflective electrode R.

[0084] Furthermore, according to the organic EL display device 50b of this embodiment, since the second planarization film 28b provided on the terminal portion T is thinner than the second planarization film 28a provided on the display area D, the depth of the contact holes formed in the second planarization film 28b and the first edge cover 33a becomes shallower, and electrical connection between the first terminal layer 26t and the fourth terminal layer 34b can be easily ensured.

[0085] 《Third Embodiment》 Figure 8 shows a third embodiment of the display device according to the present invention. Here, Figure 8 is a cross-sectional view of the terminal portion T of the organic EL display device 50c of this embodiment.

[0086] In the first and second embodiments described above, organic EL display devices 50a and 50b were shown as examples in which second planarization films 28a and 28b were provided on the terminal portion T. However, in this embodiment, an organic EL display device 50c is shown as an example in which a planarization film is not provided on the terminal portion T.

[0087] The organic EL display device 50c, like the organic EL display device 50a of the first embodiment described above, includes, for example, a display area D for displaying an image, provided in a rectangular shape, and a frame area F provided in a frame shape around the display area D and having a terminal portion T. Furthermore, the organic EL display device 50c, like the organic EL display device 50a of the first embodiment described above, includes a glass substrate 10 provided as a base substrate, a TFT layer 30 provided on the glass substrate 10, an organic EL element layer 40 provided on the TFT layer 30 as a light-emitting element layer, and a sealing film 45 provided on the organic EL element layer 40. Here, since the configuration of the display area D of the organic EL display device 50c is substantially the same as that of the organic EL display device 50a of the first embodiment described above, this embodiment will focus on describing the configuration of the terminal portion T of the organic EL display device 50c.

[0088] The organic EL display device 50c, like the organic EL display device 50a of the first embodiment described above, includes a plurality of first terminal layers 26t (see Figure 8) formed of a fifth metal film and provided along the direction in which the terminal portion T extends in the frame region F. Here, as shown in Figure 8, the first planarization film 25a and the second planarization film 28a of the display region D are not provided in the terminal portion T. Furthermore, the other configurations of the terminal portion T of the organic EL display device 50c are substantially the same as those of the terminal portion of the organic EL display device 50a of the first embodiment described above.

[0089] In the organic EL display device 50c with the above configuration, similar to the organic EL display device 50a of the first embodiment, an image is displayed in each subpixel P by appropriately emitting light from the light-emitting layer 3 of the organic EL layer 36 of the organic EL element 39 via the first TFT 9a, second TFT 9b, and third TFT 9c.

[0090] The organic EL display device 50c of this embodiment can be manufactured by changing the pattern shape of the second planarization film 28a in the TFT layer formation step of the manufacturing method of the organic EL display device 50a of the first embodiment described above.

[0091] As described above, in the organic EL display device 50c of this embodiment, in each subpixel P, the intermediate electrode 26a, which is arranged in the TFT layer 30 as a low-resistance conductive layer including a copper film and electrically connected to the first electrode E including a silver film of the organic EL element layer 40, is covered with a first metal layer 27a formed of a titanium film or titanium alloy film. Therefore, even if the laminated film of the ITO film and silver film is patterned by wet etching with a mixture of phosphoric acid, nitric acid, and acetic acid to form the reflective electrode R of the first electrode E, the etching solution is blocked by the first metal layer 27a and does not easily penetrate the intermediate electrode 26a. As a result, the copper film of the intermediate electrode 26a can be protected from the etching solution, and corrosion of the intermediate electrode 26a using the copper film of the TFT layer 30, which is electrically connected to the first electrode E using the silver film, can be suppressed.

[0092] Furthermore, according to the organic EL display device 50c of this embodiment, since no inorganic insulating film is placed between the relay electrode 26a and the reflective electrode R, it becomes easier to control the inclination of the inner surface of the contact hole formed in the second planarization film 28a, thereby easily ensuring electrical connection between the relay electrode 26a and the reflective electrode R.

[0093] Furthermore, according to the organic EL display device 50c of this embodiment, since the terminal portion T does not have a second flattening film 28a of the display area D, the depth of the contact hole formed in the first edge cover 33a becomes even shallower, and the electrical connection between the first terminal layer 26t and the fourth terminal layer 34b can be secured even more easily.

[0094] Other embodiments In the embodiments described above, an organic EL layer with a five-layer stacked structure consisting of a hole injection layer, a hole transport layer, an emissive layer, an electron transport layer, and an electron injection layer was exemplified. However, the organic EL layer may also have a three-layer stacked structure consisting of, for example, a hole injection layer / hole transport layer, an emissive layer, and an electron transport layer / electron injection layer.

[0095] Furthermore, while the above embodiments illustrate organic EL display devices in which the electrode of the TFT connected to the first electrode is used as the drain electrode, the present invention can also be applied to organic EL display devices in which the electrode of the TFT connected to the first electrode is called the source electrode.

[0096] Furthermore, although the above embodiments have described an organic EL display device as an example of a 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, a display device equipped with a QLED (Quantum-dot light-emitting diode), which is a light-emitting element using a quantum dot-containing layer. [Industrial applicability]

[0097] As described above, the present invention is useful for self-illuminating display devices. [Explanation of symbols]

[0098] D Display area E 1st electrode F Frame area P subpixel R reflective electrode T terminal section 9a First TFT (Thin Film Transistor) 9b Second TFT (Thin-Film Transistor) 9c Third TFT (Thin Film Transistor) 9d capacitor 10 Glass substrate (base substrate) 11c 1st capacitor electrode 11t 3rd terminal layer 12. Base insulating film (first inorganic insulating film) 13a First gate electrode 13b 2nd capacitor electrode 14. First gate insulating film (second inorganic insulating film) 15a Semiconductor layer 15aa Source area 15ab Drain region 15ac channel area 16a Second gate insulating film (third inorganic insulating film) 19a Second gate electrode 20 Interlayer insulating film (4th inorganic insulating film) 23a Source electrode 23b Drain electrode 23d 1st wiring layer 23t 2nd terminal layer 24a Protective insulating film (5th inorganic insulating film) 25a First planarization film (first organic insulating film) 26a Intermediate electrode (low-resistance conductive layer) 26b 2nd wiring layer 26t 1st terminal layer 27a 1st metal layer 27b 2nd metal layer 27t 3rd metal layer 28a Second planarization film (second organic insulating film) 30 TFT layer (thin film transistor layer) 34a transparent electrode 34b 4th terminal layer 36. Organic EL layer (organic electroluminescent layer, light-emitting functional layer) 37 Second electrode 40 Organic EL element layer (light-emitting element layer) 45 Sealing film 50a,50b,50c organic EL display device

Claims

1. Base board and A thin-film transistor layer is provided on the base substrate, and a low-resistance conductive layer containing a copper film is arranged corresponding to each of the multiple subpixels that constitute the display area. The device comprises a light-emitting layer provided 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 the plurality of subpixels, A display device in which each of the above first electrodes contains a silver film and is electrically connected to the above low-resistance conductive layer, The display device is characterized in that the low-resistance conductive layer is covered with a first metal layer having etching resistance to the etching solution of the silver film.

2. In the display device described in claim 1, The display device is characterized in that the first metal layer is formed of a titanium film or a titanium alloy film.

3. In the display device described in claim 1 or 2, The above etching solution is characterized by containing phosphoric acid and nitrate and acetic acid.

4. In the display device described in claim 1 or 2, In the thin-film transistor layer described above, a first metal film, a first inorganic insulating film, a second metal film, a second inorganic insulating film, a semiconductor film, a third inorganic insulating film, a third metal film, a fourth inorganic insulating film, a fourth metal film, a fifth inorganic insulating film, a first organic insulating film, a fifth metal film including the copper film, a sixth metal film, and a second organic insulating film are sequentially laminated on the base substrate. The low-resistance conductive layer is formed by the fifth metal film, A display device characterized in that the first metal layer is formed of the sixth metal film.

5. In the display device described in claim 4, The thin-film transistor layer has a source region and a drain region defined so as to be spaced apart from each other, and a channel region defined between the source region and the drain region. A thin-film transistor is arranged therein, comprising a semiconductor layer formed of the semiconductor film, a first gate electrode formed of the second metal film and provided on the base substrate side of the semiconductor layer via the second inorganic insulating film, a second gate electrode formed of the third metal film and provided on the channel region via the third inorganic insulating film, and a source electrode and a drain electrode formed of the fourth metal film, electrically connected to the source region and the drain region, respectively. The display device is characterized in that the low-resistance conductive layer is electrically connected to the drain electrode.

6. In the display device described in claim 4, A capacitor is arranged in the thin-film transistor layer, comprising a first capacitive electrode formed from the first metal film, a second capacitive electrode formed from the second metal film, and the first inorganic insulating film provided between the first and second capacitive electrodes. The second capacitance electrode is electrically connected to the first wiring layer formed by the fourth metal film. The first wiring layer is electrically connected to the second wiring layer formed by the fifth metal film. A display device characterized in that the second wiring layer is covered by a second metal layer formed by the sixth metal film.

7. In the display device described in claim 4, Each of the above first electrodes has a reflective electrode containing the above silver film and a transparent electrode provided on the reflective electrode. A frame area is provided around the above display area. A terminal portion is provided at the end of the above frame area. The terminal portion is provided with a first terminal layer formed from the fifth metal film. The first terminal layer is electrically connected to the second terminal layer formed by the fourth metal film. The second terminal layer described above is electrically connected to the third terminal layer formed by the first metal film described above. The first terminal layer is covered by a third metal layer formed by the sixth metal film. The display device is characterized in that the third metal layer is electrically connected to a fourth terminal layer formed in the same layer as the transparent electrode using the same material.

8. In the display device described in claim 7, The display device is characterized in that the terminal portion is provided with the second organic insulating film instead of the first organic insulating film.

9. In the display device described in claim 8, A display device characterized in that the second organic insulating film provided on the terminal portion is thinner than the second organic insulating film provided on the display area.

10. In the display device described in claim 7, A display device characterized in that the terminal portion described above does not have the first organic insulating film and the second organic insulating film.

11. In the display device described in claim 1 or 2, A display device characterized by comprising a sealing film provided on the above-mentioned light-emitting layer.

12. In the display device described in claim 1 or 2, A display device characterized in that at least one of the above-mentioned plurality of light-emitting functional layers is an organic electroluminescent layer.

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