JP2011040167A - Display and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display and its manufacturing method, with brightness unevenness between pixels substantially reduced while restraining inflow of overcurrent into pixels, and excellent in productivity. <P>SOLUTION: The display 100 with a plurality of light-emitting pixels 95 arranged, includes a substrate 10, a first electrode 20 formed on the substrate 10, an auxiliary wiring 30 formed in electric insulation from the first electrode 20, a light-emitting part 90 formed on the first electrode 20 and emitting light in accordance with electric current, a second electrode 80 formed at least on an upper surface of the light-emitting part 90, and an electron transport layer 70 electrically connecting the second electrode 80 and a part of the upper surface of the auxiliary wiring 30. The light-emitting part 90 includes at least the electron transport layer 70. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a display device using an organic electroluminescence (EL) element, and particularly to a display device in which luminance variation of an organic EL element is reduced and a method for manufacturing the same.

  In recent years, the demand for flat display devices such as liquid crystal displays having features such as thinness, light weight, and low power consumption has been rapidly increased compared to conventional CRT displays. However, the liquid crystal display has problems in viewing angle, responsiveness, and the like.

  In order to improve the problem, recently, a simple matrix method, an active matrix method, etc. using an organic electroluminescence element (hereinafter referred to as “organic EL element”) having self-luminous emission, high viewing angle, and high-speed response. The display device has attracted attention. In particular, active matrix display devices that are advantageous for high definition and large screens are being actively developed.

  A display device using an organic EL element includes a display panel using the organic EL element and a drive circuit for driving the organic EL element. In the display panel, on a substrate such as glass, a first electrode such as Al, a second electrode such as ITO opposed thereto, and an organic EL element provided with a light emitting layer therebetween are arranged in a matrix. Configured. The drive circuit is composed of thin film transistors (TFTs) that individually drive the organic EL elements.

  In addition, as a display device, a bottom emission method in which light emitted from an organic EL element is extracted to the outside through a substrate and a top emission method in which the light is emitted from the second electrode side facing the substrate are being studied. However, in an active matrix bottom emission display device, a thin film transistor of a driver circuit is formed over a substrate, so that it is difficult to ensure a sufficient aperture ratio.

  On the other hand, since the aperture ratio is not limited by a thin film transistor or the like in the top emission method, the use efficiency of emitted light can be increased as compared with the bottom emission method. In this case, in the top emission method, since light is extracted to the outside through the second electrode formed on the top surface of the light emitting layer, the second electrode is required to have high conductivity and high light transmittance. However, generally, the transparent conductive material used for the second electrode is a metal oxide such as ITO, but the metal oxide has a higher resistivity than the metal material. For this reason, as the display panel is increased in area, the wiring length of the second electrode varies among the light emitting pixels, and the voltage varies depending on the arrangement position of the organic EL element on the display panel surface, resulting in a decrease in display quality. was there.

  In order to solve the above problem, a display device as shown in FIG. 21 is disclosed (for example, see Patent Document 1).

  FIG. 21 is a structural cross-sectional view of a light emitting pixel included in a conventional display device described in Patent Document 1. Below, the display apparatus 700 of patent document 1 is demonstrated easily using FIG. As shown in the figure, in the display device 700, the first electrode 720 and the auxiliary wiring 730 made of a conductive material having a low resistivity are provided on the same surface as the substrate 710 by using, for example, a photolithography method. It has been. A light modulation layer 750 that is a light emitting layer is provided on the first electrode 720, and a second electrode 760 made of a transparent conductive material is provided thereon. Further, the auxiliary wiring 730 and the second electrode 760 are connected through an opening 745 partially provided in the partition wall 740.

Similarly, in Patent Document 2, the first electrode and the second current supply line are provided in different layers of the glass substrate, and the second electrode and the second current supply line are connected via a contact hole. An organic light emitting display device is disclosed. Thereby, the wiring resistance due to the second electrode can be reduced, and the luminance variation in the display surface can be reduced.
JP 2002-318556 A JP 2003-303687 A

  However, in the conventional display devices disclosed in Patent Document 1 and Patent Document 2, since the second electrode and the auxiliary wiring are directly connected, when an overcurrent flows, the display device such as the drive circuit unit is affected. May give. In addition, since an overcurrent flows through the light emitting unit, the reliability and life of the light emitting unit may be affected.

  Here, the overcurrent is a pulse-like current of several tens to several hundred times, for example, while the current required to emit light from the light emitting unit per subpixel is 3 μA to 5 μA. . The overcurrent is generated when, for example, static electricity during display panel manufacture, current due to some external noise, or other pixel is short-circuited in the completed display device.

  Further, in the conventional display devices disclosed in Patent Document 1 and Patent Document 2, since the second electrode and the auxiliary wiring are directly connected through the connection opening, the second electrode is provided even if the area of the connection opening is small. And the auxiliary wiring can be kept sufficiently low in connection resistance. In order to realize direct connection, all the layers involved in the light emitting operation such as the electron injection layer, the electron transport layer, the hole injection layer, the hole transport layer, and the light emitting layer should not cover the connection opening. Need to form.

  Therefore, for example, a high-definition mask is used to form the electron injection layer, the electron transport layer, the hole injection layer, the hole transport layer, the light emitting layer, and the like so as not to cover the connection opening by using, for example, a vacuum deposition method. There is a need. However, the use of a high-definition mask has a problem in alignment and the like when manufacturing a large-screen or high-definition display device with high productivity.

  In addition, as a structure for realizing the connection opening without using the above-described high-definition mask and suppressing overcurrent, the laminated structure of the light emitting part is left as it is between the auxiliary electrode and the second electrode. Arranged structures are conceivable. In this case, simultaneously with the formation of the light emitting portion, the laminated structure of the light emitting portion is formed on the auxiliary electrode, and the second electrode can be formed without going through the patterning process of the connection opening using a high-definition mask. . However, this structure shows diode characteristics in the forward direction with respect to the direction of current flow in the light emitting part, but on the contrary, the connection opening has diode characteristics in the reverse direction with respect to the direction of current flow. Resulting in. Therefore, although it has an effect in suppressing overcurrent, it does not have appropriate conductivity between the auxiliary wiring and the second electrode, so that reduction in luminance variation, which is the original purpose, cannot be achieved.

  The present invention has been made to solve the above-described problems, and provides a display device and a method for manufacturing the display device that suppresses the inflow of overcurrent into the pixel and significantly reduces luminance variation between pixels, and is excellent in productivity. The purpose is to provide.

  In order to achieve the above object, the present invention provides a display device in which a plurality of light emitting pixels are arranged, a substrate, a first electrode formed on or in the substrate, and the first electrode and the electric device. Auxiliary wiring formed insulatively, a light emitting part formed on the first electrode and emitting light according to current, a second electrode formed at least on the upper surface of the light emitting part, the second electrode, A connecting portion that electrically connects at least a part of the upper surface of the auxiliary wiring, and the light emitting portion is one of a light emitting layer and at least an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer. The connection portion includes at least one of an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer other than the light emitting layer.

  As a result, it is possible to suppress the inflow of overcurrent into the pixels and greatly reduce the luminance variation between the pixels. In the present invention, the connecting portion is a component of the light emitting portion between the auxiliary wiring and the second electrode, and includes at least an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer other than the light emitting layer. It is the structure including any one layer. Since the layer provided in the connection portion has a higher electrical resistance than the metal of the auxiliary wiring and the ITO of the second electrode, the overcurrent can be effectively suppressed by functioning as an electrical buffer layer against the overcurrent. . In addition, the layer provided in the connection portion described above is usually deposited on the substrate by a vacuum deposition method or the like, but the patterning process of the layer using a high-definition mask is not necessary, so that the screen is enlarged and the definition is high. This is advantageous for the conversion.

  Further, the connection portion has a multilayer structure, the multilayer structure has a reverse diode characteristic, and a layer having the reverse diode characteristic with respect to a voltage applied to the connection portion. The reverse breakdown voltage may be low.

  The connecting portion is a component of the light emitting portion between the auxiliary wiring and the second electrode, and at least one of the electron injection layer, the electron transport layer, the hole injection layer, and the hole transport layer other than the light emitting layer. In the case of the configuration including the above, it is conceivable that the reverse diode characteristic appears in the direction in which the current flows depending on the material selection of the connection portion. However, with this configuration, an avalanche current is generated because the voltage applied to the entire connection portion is larger than the reverse breakdown voltage of the characteristics of the configuration. Therefore, it is possible to suppress the inflow of overcurrent into the pixel and to greatly reduce the luminance variation between the pixels.

  Further, it is preferable that the connection portion does not have a diode characteristic in a reverse direction between the second electrode and the auxiliary wiring.

  As a result, since there is no reverse diode characteristic between the second electrode and the auxiliary wiring, the connecting portion functions as a conductive layer, whereby the luminance variation between the pixels can be greatly reduced.

  The substrate includes at least a first layer and a second layer different from the first layer, the first electrode is formed on the first layer, and the auxiliary wiring is formed on the second layer. It may be formed.

  As a result, the arrangement position and area of the auxiliary wiring are not easily limited by the arrangement of the first electrode, so that a display device with a high degree of design freedom can be realized. For example, by providing the auxiliary wiring and the first electrode in different layers of the substrate, the auxiliary wiring and the first electrode can be formed so as to overlap each other, so that the area of the auxiliary wiring can be greatly increased. Correspondingly, the connection area between the auxiliary wiring and the joint can be enlarged. As a result, overcurrent can be effectively suppressed. Furthermore, since the first electrode and the auxiliary wiring can be three-dimensionally arranged, restrictions on the shape and size of the wiring electrode can be greatly relaxed. In addition, since the first electrode and the auxiliary wiring can be made of different materials, the range of selection is expanded according to the required resistivity for the auxiliary wiring and the optimal material for the first electrode according to the configuration of the light emitting unit. To do. For example, in the case of the bottom emission method, the first electrode can be formed of a transparent conductive material, and the auxiliary wiring can be formed of a metal material.

  Further, at least one of the electron injection layer, the electron transport layer, the hole injection layer, and the hole transport layer included in the connection portion is continuously formed over the light emitting portion and the connection portion. Is preferred.

  Thereby, since the layer which the connection part has is integrally provided with the layer which the light emission part has, the display apparatus excellent in productivity is realizable.

  In the display device, the plurality of light-emitting pixels are arranged in a matrix, the first electrode and the light-emitting portion are provided to be separated at least for each light-emitting pixel, and the auxiliary wiring is at least the It is preferable that the light-emitting pixel column is disposed in any one of the light-emitting pixel columns and the light-emitting pixel rows.

  As a result, the wiring resistance depending on the distance between the second electrode and the auxiliary wiring can be reduced, the fluctuation of the driving voltage can be suppressed, and a color display device with high display quality can be realized. The overcurrent resistance characteristics can be improved.

  Each of the plurality of light emitting pixels includes at least three subpixels, the first electrode and the light emitting unit are provided separately for each subpixel, and the auxiliary wiring includes at least the subpixel. It may be arranged for each column and for each sub-pixel row.

  As a result, the wiring resistance depending on the distance between the second electrode and the auxiliary wiring can be greatly reduced, the fluctuation of the driving voltage can be further suppressed, and a color display device with high display quality can be realized.

  Each of the plurality of light emitting pixels includes at least three subpixels, the first electrode and the light emitting unit are provided separately for each subpixel, and the auxiliary wiring includes at least the light emitting pixel. You may arrange | position to either every column and every said light emitting pixel row.

  As a result, the number of auxiliary wirings and the number of junction points can be reduced between the auxiliary wiring and the second electrode as compared with the case where the auxiliary wiring is provided for each sub-pixel. It becomes possible to connect. As a result, the voltage fluctuation of the second electrode can be further suppressed, and the display uniformity of the display panel can be improved.

  Moreover, it is preferable that the said electron carrying layer contains at least any one among an alkali metal, alkaline-earth metal, and these compounds.

  Thereby, electron transport efficiency and injection efficiency can be improved.

  The substrate further includes an interlayer insulating layer disposed under the first electrode, and a driving circuit layer disposed under the interlayer insulating layer and having a driving element for driving the light emitting pixel, The first electrode and the driving element may be connected via a conductive via provided in the interlayer insulating layer.

  Thus, an active matrix display device in which a driving circuit is integrated in the pixel portion can be realized.

  The driving element is preferably a thin film transistor, and the first electrode is preferably connected to a source terminal or a drain terminal of the driving element through the conductive via.

  Thereby, even if the connection resistance between the second electrode and the auxiliary wiring fluctuates, fluctuations in the voltage applied to the light emitting unit can be suppressed. As a result, a display device with excellent display quality can be realized.

  The display device manufacturing method of the present invention is a display device manufacturing method in which a plurality of light emitting pixels are arranged, and is electrically insulated from the first electrode and the first electrode on or in the substrate. A first forming step of forming an auxiliary wiring; and a light emitting layer and at least one of an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer on the first electrode, and according to a current Forming a light emitting part that emits light and a connection part including at least one of the electron injection layer, the electron transport layer, the hole injection layer, and the hole transport layer on the auxiliary wiring; and And a third forming step of forming a second electrode on at least the light emitting portion and the connecting portion after the second forming step.

  By this method, it is possible to manufacture a display device in which the auxiliary wiring and the second electrode are connected with a wide connection area and the wiring resistance of the second electrode is greatly reduced. And since it connects through at least one of an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer, the display device is connected with a small connection resistance that does not cause a practical problem as a display panel Can be easily manufactured. Furthermore, since it is not necessary to use a high-definition mask to deposit on the substrate of the display panel by, for example, a vacuum deposition method, it is possible to easily cope with a large screen and a high definition. In addition, since it is not necessary to pattern the layers constituting the connection portion, the manufacturing process can be simplified and the productivity can be improved.

  The substrate includes at least a first layer and a second layer different from the first layer. In the first formation step, the first electrode is formed on the first layer, and the second layer is formed. The auxiliary wiring may be formed on the substrate.

  By this method, the formation position and area of the auxiliary wiring are not easily limited by the arrangement of the first electrode, and a display device with a high degree of design freedom can be manufactured.

  According to the present invention, it is possible to realize a display device with high display quality that suppresses inflow of overcurrent into a pixel and significantly reduces luminance variation between pixels by reducing wiring resistance. In addition, since the manufacturing process can be simplified, a method for manufacturing a display device with excellent productivity can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments and drawings, the same components will be described with the same reference numerals. In the following, a display device including an organic EL element in which a top emission type anode (anode) is a first electrode and a cathode (cathode) is a second electrode will be described as an example, but the present invention is not limited thereto.

(Embodiment 1)
Hereinafter, the display device according to Embodiment 1 of the present invention will be described with reference to the drawings.

  FIG. 1A is a partial plan view for explaining a main part of the display device according to Embodiment 1 of the present invention. FIG. 1B is a cross-sectional view of the main part taken along the line A-A ′ of FIG.

  The display device 100 according to the present embodiment illustrated in FIG. 1B is provided on the substrate 10, the first electrode 20 and the auxiliary wiring 30 provided on the substrate 10, and the first electrode 20. A hole injection layer 40; a partition wall 50 that forms a pixel opening 45 and a connection opening 35; a light emitting layer 60 provided in the pixel opening 45; an electron transport layer 70 provided on the upper surface thereof; The second electrode 80 is provided on the transport layer 70.

  Further, as described in FIG. 1A, in the display device 100, the light emitting pixels 95 including the light emitting units 90 are arranged in a matrix, and the auxiliary wiring 30 is provided for each light emitting pixel column along each light emitting unit 90. It is arranged and provided. In addition, the electron carrying layer 70 and the 2nd electrode 80 which were described in FIG.1 (b) are formed over the whole surface of the partial top view described in FIG.1 (a). The auxiliary wiring 30 and the second electrode 80 are electrically connected to each other through a connection portion made of the electron transport layer 70 in the connection opening 35 provided along the auxiliary wiring 30. At this time, the second electrode 80, the electron transport layer 70, and the auxiliary wiring 30 are configured to be in ohmic connection or diode connection with respect to the direction of current flow. That is, the connection has a structure that does not have diode characteristics in the reverse direction from the second electrode 80 toward the auxiliary wiring 30. Furthermore, in order to realize the suppression of the overcurrent inflow which is the subject of the present invention, the electron transport layer 70 which is a constituent layer of the connection portion is higher than the electric resistance value of the second electrode and the auxiliary wiring in the stacking direction. It preferably has an electrical resistance value.

  Note that the structure is not limited to the above structure as long as the connection structure is a layer structure that does not block the current flow in the direction in which the current flows. For example, even if the structure between the second electrode 80 and the auxiliary wiring 30 is a multi-layer structure and has a diode characteristic in the reverse direction with respect to the direction of current flow, the second electrode 80 and the auxiliary wiring 30. If the reverse breakdown voltage of the layer having the diode characteristics in the reverse direction in the multilayer structure is lower than the voltage applied between the two, an avalanche current is generated. Therefore, the display device having the multilayer structure is also included in the present invention, and has the same effect as the display device 100 according to the first embodiment described in FIG.

  The light emitting unit 90 includes at least the light emitting layer 60, the hole injection layer 40, and the electron transport layer 70 provided in the pixel opening 45, and is formed by recombination of electrons and holes injected into the light emitting layer 60. The generated light is emitted from the second electrode 80 surface side. Note that a plurality of the first electrodes 20 are provided separately corresponding to the light emitting units 90. That is, when the light emitting unit is composed of at least three subpixels such as RGB, the light emitting unit 90 and the first electrode 20 are provided separately from each other corresponding to each subpixel.

  Here, the substrate 10 is not particularly limited. For example, a glass substrate, a quartz substrate, or the like is used. Further, using a plastic substrate such as polyethylene terephthalate or polyethersulfone, bendability can be imparted to the display device. In particular, as in this embodiment, in the case of the top emission method, an opaque plastic substrate or a ceramic substrate can be used.

  Further, the first electrode 20 and the auxiliary wiring 30 are not particularly limited, but it is preferable to use a material having a low electrical resistivity, for example, silver, aluminum, nickel, chromium, molybdenum, copper, iron, platinum, tungsten, lead , Tin, antimony, strontium, titanium, manganese, indium, zinc, vanadium, tantalum, niobium, lanthanum, cerium, neodymium, samarium, europium, palladium, copper, cobalt, any of these metals, alloys of these metals Or a laminate of them can be used.

  Moreover, the hole injection layer 40 which comprises a light emission part is a layer which has a hole injection material as a main component. The hole injecting material is a material having a function of injecting holes injected from the first electrode 20 side into the light emitting layer stably or by assisting the generation of holes. As the hole injection layer 40, for example, PEDOT (polyethylenedioxythiophene) can be used.

In addition, as the light emitting layer 60 forming the light emitting portion, a low molecular weight or high molecular weight organic light emitting material can be used. As the polymer light-emitting material, for example, a polymer light-emitting material such as polyparaphenylene vinylene (PPV) or polyfluorene can be used. Moreover, as a low molecular weight light emitting material, in addition to Alq ₃ and Be-benzoquinolinol (BeBq ₂ ), 2,5-bis (5,7-di-t-pentyl-2-benzoxazolyl)- 1,3,4-thiadiazole, 4,4'-bis (5,7-benzyl-2-benzoxazolyl) stilbene, 4,4'-bis [5,7-di- (2-methyl-2- Butyl) -2-benzoxazolyl] stilbene, 2,5-bis (5,7-di-t-benzyl-2-benzoxazolyl) thiophine, 2,5-bis ([5-α, α- Dimethylbenzyl] -2-benzoxazolyl) thiophene, 2,5-bis [5,7-di- (2-methyl-2-butyl) -2-benzoxazolyl] -3,4-diphenylthiophene, 2,5-bis (5-methyl-2-benzoxazolyl) thio 4,4'-bis (2-benzoxazolyl) biphenyl, 5-methyl-2- [2- [4- (5-methyl-2-benzoxazolyl) phenyl] vinyl] benzoxazo Benzoxazoles such as ril, 2- [2- (4-chlorophenyl) vinyl] naphtho [1,2-d] oxazole, benzothiazoles such as 2,2 ′-(p-phenylenedivinylene) -bisbenzothiazole , 2- [2- [4- (2-benzimidazolyl) phenyl] vinyl] benzimidazole, 2- [2- (4-carboxyphenyl) vinyl] benzimidazole, and other fluorescent whitening agents such as Tris, (8-quinolinol) aluminum, bis (8-quinolinol) magnesium, bis (benzo [f] -8-quinolinol) zinc, bis 2-methyl-8-quinolinolate) aluminum oxide, tris (8-quinolinol) indium, tris (5-methyl-8-quinolinol) aluminum, 8-quinolinol lithium, tris (5-chloro-8-quinolinol) gallium, bis ( Metal-chelating oxinoid compounds such as 8-hydroxyquinoline-based metal complexes such as 5-chloro-8-quinolinol) calcium and poly [zinc-bis (8-hydroxy-5-quinolinonyl) methane] and dilithium ependridione 1,4-bis (2-methylstyryl) benzene, 1,4- (3-methylstyryl) benzene, 1,4-bis (4-methylstyryl) benzene, distyrylbenzene, 1,4-bis (2 -Ethylstyryl) benzene, 1,4-bis (3-ethylstyryl) ben , 1,4-bis (2-methylstyryl) 2-methylbenzene and other styrylbenzene compounds, 2,5-bis (4-methylstyryl) pyrazine, 2,5-bis (4-ethylstyryl) pyrazine 2,5-bis [2- (1-naphthyl) vinyl] pyrazine, 2,5-bis (4-methoxystyryl) pyrazine, 2,5-bis [2- (4-biphenyl) vinyl] pyrazine, 2, Distylpyrazine derivatives such as 5-bis [2- (1-pyrenyl) vinyl] pyrazine, naphthalimide derivatives, perylene derivatives, oxadiazole derivatives, aldazine derivatives, cyclopentadiene derivatives, styrylamine derivatives, Coumarin derivatives and aromatic dimethylidin derivatives are used. Furthermore, anthracene, salicylate, pyrene, coronene and the like are also used. Alternatively, a phosphorescent material such as fac-tris (2-phenylpyridine) iridium can be used.

  The electron transport layer 70 is a layer mainly composed of an electron transport material. The material having an electron transporting property has both the property of being an electron acceptor and easily becoming an anion, and the property of transferring generated electrons by a charge transfer reaction between molecules, and the charge from the second electrode 80 to the light emitting layer 60. A material that is suitable for transportation. Examples of the electron transport layer 70 include oxadiazole derivatives such as 1,3-bis (4-tert-butylphenyl-1,3,4-oxadiazolyl) phenylene (OXD-7), anthraquinodimethane derivatives, and diphenyl. Polymer materials such as quinone derivatives and silole derivatives, bis (2-methyl-8-quinolinolate)-(para-phenylphenolate) aluminum (BAlq), bathopproin (BCP), and the like are used. At this time, as will be described later, for example, an alkali metal such as lithium, sodium, calcium, rubidium, cesium, and francci and at least one of, for example, magnesium, calcium, strontium, barium, and radium alkaline earth metal as a main component. Alternatively, the electron transport layer 70 may be configured by stacking metal layers. In addition, the metal layer may contain two or more kinds of alkali metals and alkaline earth metals.

  Further, as the partition wall 50, a resin material such as polyimide resin can be used. At this time, for example, carbon particles may be included in the resin in order to prevent transmission of light generated in the light emitting part to the adjacent light emitting part.

  The second electrode 80 is not particularly limited, but in the case of the top emission method, it is preferable to use indium tin oxide or indium zinc oxide.

  According to the present embodiment, the auxiliary wiring and the second electrode are connected to face each other via the connection portion made of the electron transport layer, so that overcurrent can be effectively limited. Accordingly, it is possible to reduce the influence of overcurrent on the light emitting unit, the drive circuit, and the like, and to realize a display device with excellent reliability. Conventionally, in order to directly connect the auxiliary wiring and the second electrode, a high-definition mask for excluding the constituent layer of the light emitting portion at the connection portion is necessary. On the other hand, in the present invention, since the high-definition mask is not required, the panel can be easily increased in definition and size. As a result, it is possible to realize a display device that is excellent in display quality with small variations in luminance of each light emitting portion over the entire display panel. In addition, since the power loss at the second electrode and the like can be suppressed by reducing the wiring resistance and the drive voltage can be reduced, the display device has a long life and excellent reliability that prevents breakdown due to the electric field applied to the light emitting portion. Can be realized.

  Below, the manufacturing method of the display apparatus in Embodiment 1 of this invention is demonstrated in detail, referring drawings.

  2 and 3 are cross-sectional views illustrating the method for manufacturing the display device according to the first embodiment of the present invention.

  First, as shown in FIG. 2A, for example, Al is deposited on a substrate 10 provided with a drive circuit (not shown) composed of, for example, a TFT (Thin Film Transistor) and a capacitor. Using the method, it is formed on the entire surface. Then, Al is etched using a photolithography method to form the first electrode 20 at a predetermined position and the auxiliary wiring 30 at a position electrically insulated from the first electrode. At this time, the first electrode 20 is individually formed corresponding to the light emitting portion, and the auxiliary wiring 30 is one-dimensionally along, for example, the rows or columns of the light-emitting pixels arranged in a two-dimensional matrix. Arranged and formed. For example, in order to eliminate unevenness due to a drive circuit or the like, the substrate 10 may be provided with a planarization layer as necessary, and the first electrode 20 and the auxiliary wiring 30 may be formed thereon.

  Next, as shown in FIG. 2B, for example, PEDOT or the like that becomes the hole injection layer 40 is formed at a position corresponding to at least the pixel opening on the first electrode 20 by using, for example, an inkjet method. Film.

  Next, as shown in FIG. 2C, a negative photoresist 50A is applied to the entire surface.

  Next, as shown in FIG. 2D, a mask 110 having a light shielding portion is positioned and placed on the negative photoresist 50A at positions corresponding to the light emitting portion and the connecting portion. Then, the photoresist 50A is exposed through the mask 110 using a photolithography method.

  Next, as shown in FIG. 2E, the mask 110 is removed and development processing is performed to form a partition wall 50 that constitutes the pixel opening 45 and the connection opening 35.

  Next, as shown in FIG. 3A, a paste material to be a light emitting layer is applied into the pixel opening 45 by using, for example, an ink jet method. At this time, the paste material that becomes the light emitting layer is applied in a state of rising from the pixel opening 45 due to surface tension.

  Next, as shown in FIG. 3B, the paste material is dried at, for example, about 80 ° C. for about 30 minutes, and the light emitting layer 60 is formed by volatilizing the solvent component of the paste material. At this time, in the case where the light emitting unit is composed of at least three different sub-pixels such as RGB, the light emission different in each sub-pixel is obtained by repeating FIG. 3A and FIG. 3B for each sub-pixel. A pixel in which a part of the light emitting layer is formed is formed.

  Next, as shown in FIG. 3C, the electron transport layer 70 is formed on the entire surface by using, for example, a vacuum deposition method so as to cover at least the light emitting portion and the connection opening. Thus, a connection portion that is electrically connected to a part of the upper surface of the auxiliary wiring is formed in the connection opening.

  Next, as shown in FIG. 3D, on the electron transport layer 70, for example, indium tin oxide or the like is formed using a sputtering method, and the second electrode 80 is formed on the entire surface. Thereby, the second electrode 80 and the auxiliary wiring 30 are electrically connected via the electron transport layer 70.

  Thereafter, for example, a protective layer is formed by providing a resin layer or glass, and the display device 100 is manufactured.

  According to the manufacturing method of the display device of the present embodiment, since the auxiliary wiring and the second electrode are connected to face each other through the electron transport layer of the connection portion, the characteristics of the drive circuit and the light emitting portion are deteriorated due to overcurrent. It is possible to manufacture a display device that is suppressed by the electron transport layer and has excellent reliability such as life.

  In addition, it is preferable that the film-forming process of the electron carrying layer 70 described in FIG.3 (c) and the film-forming process of the 2nd electrode 80 described in FIG.3 (d) are continuous dry processes. . Here, the continuous dry process is a process in which a work in progress is transferred between film forming processes using a sputtering method or a vapor deposition method while maintaining a high degree of vacuum. By making the series of processes from the film forming step of the electron transport layer 70 to the film forming step of the second electrode 80 the continuous dry process, the manufacturing process is simplified. In addition, since an unnecessary oxide layer or the like is prevented from intervening at the interface between the electron transport layer 70 and the second electrode 80, it contributes to high light emission efficiency, low driving voltage, and long life.

  In addition, according to the present embodiment, at least the light emitting layer, the electron transport layer, and the second electrode can be formed basically without interposing a high-definition mask. As a result, the display device can be efficiently manufactured with high productivity.

  In the present embodiment, the hole injection layer / light emitting layer / electron transport layer has been described as an example of the configuration of the light emitting unit, but is not limited thereto. For example, the light-emitting structure may have a structure including at least one of a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer in addition to the light-emitting layer. In addition to the electron transport layer, at least one of an electron injection layer, a hole injection layer, and a hole transport layer as a connection portion interposed between the second electrode and the auxiliary wiring, corresponding to the configuration of the light emitting portion. One layer may be provided. That is, the connection portion may have a laminated structure such as an electron transport layer, an electron injection layer, a hole injection layer, and a hole transport layer.

  In this case, it is preferable that the connecting portion is configured so that a current flowing from the second electrode toward the auxiliary wiring does not have a reverse diode characteristic.

  However, for example, when a hole injection layer and an electron transport layer are stacked as a connection portion, a case where a current flowing from the second electrode toward the auxiliary wiring has diode characteristics in the reverse direction is assumed. . Even in this case, an avalanche current is generated from the second electrode toward the auxiliary wiring when the reverse breakdown voltage of the diode characteristics in the reverse direction of the stacked structure is lower than the voltage applied to the connection portion. Therefore, the display device having the above laminated structure is also included in the present invention, and has the same effect as the display device 100 according to the first embodiment shown in FIG.

  On the other hand, when the reverse breakdown voltage of the reverse direction diode characteristic of the stacked structure is lower than the voltage applied to the connection portion, the current path from the second electrode toward the auxiliary wiring is interrupted, and the light emission Therefore, the current path is also cut off. Such a laminated structure is incompatible with the present invention.

  That is, the combination is arbitrary as long as it is a layer structure that does not block the current flowing in the connection portion with respect to the current flowing in the light emitting portion.

  Here, the electron injection layer is a layer mainly composed of an electron injecting material. The electron injecting material is a material having a function of injecting electrons injected from the second electrode 80 side into the light emitting layer 60 stably or by assisting generation of electrons.

  The hole transport layer is a layer mainly composed of a hole transport material. The hole transporting material has both the property of having an electron donor property and easily becoming a cation (hole) and the property of transmitting the generated hole by a charge transfer reaction between molecules, and emitting light from the first electrode 20. A material that has suitability for charge transport to the layer 60.

  In this embodiment, the display device having a partition is described as an example. However, the present invention is not limited to this. For example, in FIG. 2B, the light emitting layer may be applied only to the pixel opening by providing a layer that repels the paste material of the light emitting layer in a region other than the hole injection layer 40. This eliminates the need for a partition formation step, and can further improve productivity.

  Next, a display device showing a first modification according to Embodiment 1 of the present invention will be described with reference to FIGS.

  FIG. 4 is a cross-sectional view of a principal part of the display device showing the first modification example according to Embodiment 1 of the present invention. FIG. 4 is a cross-sectional view taken along the line A-A ′ of FIG. 1A as in FIG. FIG. 5 is a cross-sectional view for explaining the method for manufacturing the display device according to the first modification example of the first embodiment of the present invention. The display device 150 illustrated in FIG. 4 includes a substrate 10, a first electrode 20, an auxiliary wiring 30, a hole injection layer 40, a partition wall 50, a light emitting layer 60, an electron transport layer 70, and a second device. An electrode 80. The display device 150 illustrated in FIG. 4 is different from the display device 100 illustrated in FIG. 1B in that the hole injection layer 40 is formed in a region other than the connection opening 35 of the auxiliary wiring 30. The configuration is different. Note that the planar layout of the display device 150 is the same as the planar layout of the display device 100 described in FIG.

  Moreover, the display apparatus 150 is manufactured by the method shown below. Note that the manufacturing method of the display device 150 is basically the same as the manufacturing method of the display device 100, and different processes are mainly described, and description of the same processes may be omitted.

  First, as shown in FIG. 5A, the first electrode 20 and the first electrode are electrically insulated from each other at a predetermined position on the substrate 10 provided with a drive circuit (not shown) composed of, for example, a TFT and a capacitor. The auxiliary wiring 30 is formed at the position.

  Next, as shown in FIG. 5B, a transition metal oxide such as, for example, molybdenum oxide, tungsten oxide, and vanadium oxide, which becomes the hole injection layer 40, is formed on the entire surface by using, for example, a sputtering method. To do.

  Next, as shown in FIG. 5C, a resist film 115 is formed in which an opening is formed at a position to be a connection opening 35 formed along the auxiliary wiring 30.

  Next, as shown in FIG. 5D, the hole injection layer 40 is etched through the opening of the resist film 115. Thereby, the auxiliary wiring 30 is exposed.

  Next, as shown in FIG. 5E, after applying a negative photoresist 50A, a mask 110 having an opening is positioned and placed at a position corresponding to the light emitting portion and the connecting portion. Then, the photoresist 50A is exposed through this opening by using a photolithography method.

  Next, as shown in FIG. 5 (f), the mask 110 is removed, and development processing is performed to form a partition wall 50 that forms the pixel opening 45 and the connection opening 35.

  Thereafter, although not described, the display device 150 is manufactured by the same method as that shown in FIGS.

  Thereby, since a positive hole injection layer can be formed in a lump, productivity improves. In addition, a hole injection layer having a uniform thickness can be easily formed, and display variations can be suppressed.

  In the display device 150 described above, the hole injection layer 40 made of a transition metal has been described as being formed in a region other than the connection opening 35. However, as in the display device 100, only the first electrode 20 is exposed to photo. The hole injection layer 40 may be formed using a lithography method.

  In the present embodiment, the auxiliary wiring is arranged for each light emitting pixel column, but is not limited thereto. FIG. 6 is a partial plan view for explaining a main part of the display device according to the second modification example of the first embodiment of the present invention. As in the display device 200 shown in the figure, the auxiliary wirings 30 and 32 may be two-dimensionally arranged along the light emitting pixel rows and the light emitting pixel columns. As a result, the connection area between the auxiliary wirings 30 and 32 and the second electrode 80 can be expanded, the current density can be reduced, and the buffering effect against overcurrent can be improved. In addition, since the wiring resistance depending on the distance between the second electrode and the auxiliary wiring can be reduced, variation in driving voltage due to the position of the light emitting unit can be suppressed. As a result, a display device with higher display quality can be realized.

  FIG. 7 is a partial plan view for explaining a main part of the display device according to the third modification example of the first embodiment of the present invention. In the display device 250 shown in the figure, the light emitting pixel 97 is composed of at least three sub-pixels such as RGB. As in this case, the auxiliary wiring 30 may be arranged one-dimensionally along the light-emitting pixel for each light-emitting pixel column for each light-emitting pixel in which the three sub-pixels are combined.

  Thereby, since the opening area of a sub pixel can be expanded, a display device with high display luminance can be realized. Furthermore, if the area of the auxiliary wiring 30 is increased, the density of current flowing into the auxiliary wiring can be further reduced to improve the reliability, and the alignment accuracy of the mask and the like can be greatly relaxed, so that the productivity can be further improved. .

  FIG. 8 is a partial plan view for explaining the main part of the display device showing the fourth modification example according to Embodiment 1 of the present invention. In the display device 300 shown in the figure, the light emitting pixel 98 is composed of at least three sub-pixels such as RGB. As in this case, the auxiliary wiring 30 may be two-dimensionally arranged for each light emitting pixel column, and the auxiliary wiring 32 may be two-dimensionally arranged for each light emitting pixel row for each light emitting pixel in which the three sub-pixels are combined.

  Thereby, for example, the wiring resistance depending on the distance between the second electrode and the auxiliary wiring in the sub-pixel arranged at the center of the three sub-pixels can be reduced, and thus the luminance variation between the sub-pixels is further suppressed. be able to.

  In the present embodiment, the example in which the connection portion is configured by a single electron transport layer has been described, but the present invention is not limited to this. FIG. 9 is a partial plan view of a display device showing a fifth modification example according to Embodiment 1 of the present invention. The display device 350 shown in the figure includes the substrate 10, the first electrode 20, the auxiliary wiring 30, the hole injection layer 40, the partition wall 50, the light emitting layer 60, the electron transport layer 70, and the electron injection. A layer 75 and a second electrode 80 are provided. The display device 300 illustrated in FIG. 9 is different in structure from the display device 100 illustrated in FIG. 1B in that an electron injection layer 75 is inserted as a lower layer of the electron transport layer 70. Hereinafter, the description of the same points as the display device 100 described in FIG. 1B will be omitted, and only different points will be described.

  The electron injection layer 75 has a function of injecting electrons injected from the second electrode side, which is a cathode, into the light emitting layer of the organic layer 13 in a stable manner or assisting the generation of electrons. It is a metal layer mainly composed of at least one of a metal and an alkaline earth metal.

  Thereby, the transport efficiency of the electron to the light emitting layer 60 can be improved.

(Embodiment 2)
Hereinafter, a display device according to Embodiment 2 of the present invention will be described with reference to the drawings.

  FIG. 10 is a partial cross-sectional view illustrating a main part of the display device according to Embodiment 2 of the present invention. As shown in the figure, the display device 400 includes a substrate 210 and a display unit 100A. The substrate 210 includes a drive circuit layer 220 on which a drive element for driving the light emitting unit is formed, and an interlayer insulating layer 230 formed on the drive circuit layer 220. The display unit 100 </ b> A corresponds to a configuration other than the substrate 10 of the display device 100. Display device 400 according to the present embodiment is different from the first embodiment in the configuration of the substrate. Hereinafter, description of the same points as those of the display device 100 described in the first embodiment will be omitted, and only different points will be described.

  The drive circuit layer 220 is composed of a drive element (not shown) formed of an FET such as a thin film transistor (TFT), for example. A thin film transistor serving as a driving element is generally composed of a source electrode and a drain electrode facing each other with a gate electrode and an insulating film interposed therebetween, but detailed description thereof is omitted.

  The interlayer insulating layer 230 is formed on the drive circuit layer 220. The first electrode 20 and an electrode terminal (not shown) of the drive element are connected via a conductive via 240 formed in the interlayer insulating layer 230.

  The display unit 100 </ b> A is formed on the interlayer insulating layer 230.

  Hereinafter, the drive circuit layer 220 for driving the light emitting unit will be described with reference to the drawings. FIG. 11 is a main circuit configuration diagram of the display device according to the second embodiment of the present invention. As shown in the figure, the drive circuit layer 220 includes a switching transistor Tr1 made of Nch-FET, a drive transistor Tr2 made of Pch-FET, and a storage capacitor C as drive elements. The drain electrode of Tr1 is connected to the data line, the gate electrode of Tr1 is connected to the scanning line, and the source electrode of Tr1 is connected to the storage capacitor C and the gate electrode of Tr2. The drain electrode of Tr2 is connected to the power supply Vdd, and the source electrode of Tr2 is connected to the first electrode 20 of the light emitting unit.

  In this configuration, when a selection signal is input to the scanning line and Tr1 is opened, the data signal supplied via the data line is written to the holding capacitor C as a voltage value. Then, the holding voltage written in the holding capacitor C is held throughout one frame period, and by this holding voltage, the conductance of Tr2 changes in an analog manner, and a forward bias current corresponding to the light emission gradation is supplied to the first electrode. Is done. Further, the forward bias current supplied to the first electrode flows via the auxiliary wiring via the light emitting portion and the second electrode, for example, a connection portion such as an electron transport layer. As a result, the light emitting layer of the light emitting unit emits light according to the current and is displayed as an image.

  In addition, according to the present embodiment, the first electrode is connected to the source electrode of the drive element of the drive circuit, and the current flows through the auxiliary wiring.

  As a result, the active matrix display device 400 integrated with the drive circuit layer 220 can be realized with a simple configuration, and the luminance variation between the pixels can be greatly reduced while suppressing the inflow of overcurrent into the pixels. Is possible.

  Note that FIG. 11 is an example of a main circuit configuration of the display device, and it goes without saying that other circuit configurations can be appropriately applied to the present invention. For example, the same effect can be obtained even in a circuit configuration in which the first electrode is connected to the drain electrode of the drive element.

(Embodiment 3)
Hereinafter, a display device according to Embodiment 3 of the present invention will be described with reference to the drawings.

  FIG. 12A is a partial plan view for explaining a main part of the display device according to Embodiment 3 of the present invention. FIG. 12B is a cross-sectional view of the main part taken along the line A-A ′ of FIG.

  As illustrated in FIG. 12B, the display device 500 of this embodiment includes a substrate 310, the first electrode 20 provided on the substrate 310, and the auxiliary wiring 330 provided in the substrate 310. The hole injection layer 40 provided on the first electrode 20, the partition wall 50 for forming the pixel opening 45 and the connection opening 335, the light emitting layer 60 provided in the pixel opening 45, and the upper surface thereof The electron transport layer 70 is provided, and the second electrode 80 is provided on the electron transport layer 70.

  The substrate 310 is composed of a plurality of layers and is the uppermost layer of the substrate 310, and includes a first layer 312 and a second layer 314. The first electrode 20 is formed on the first layer 312, and the auxiliary wiring 330 is formed on the second layer 314.

  In the display device 400 according to the present embodiment, as compared with the display device 100 according to the first embodiment, the substrate 10 includes a plurality of layers, and the first electrode 20 is provided on the uppermost layer of the substrate. The configuration differs in that the auxiliary wiring 330 is formed in a layer different from the upper layer.

  In addition, as illustrated in FIG. 12A, in the display device 400, the light emitting pixels 99 including the light emitting units 90 are arranged in a matrix, and the auxiliary wiring 330 is arranged for each light emitting pixel column along each light emitting unit 90. It is arranged and provided. Note that the electron transport layer 70 and the second electrode 80 illustrated in FIG. 12B are formed over the entire surface of the partial plan view illustrated in FIG. The auxiliary wiring 330 and the second electrode 80 are electrically connected to each other through a connection portion made of the electron transport layer 70 at a connection opening 335 provided along the auxiliary wiring 330. At this time, the second electrode 80, the electron transport layer 70, and the auxiliary wiring 330 are configured to be in ohmic connection or diode connection with respect to the direction of current flow. That is, the connection has a structure that does not have diode characteristics in the reverse direction from the second electrode 80 toward the auxiliary wiring 330. Furthermore, in order to realize the suppression of the overcurrent inflow into the light emitting pixel, which is the subject of the present invention, the electron transport layer 70 which is a component layer of the connection portion has an electric resistance of the second electrode and the auxiliary wiring with respect to the stacking direction. It is preferable to have an electric resistance value higher than the value.

  Note that the structure is not limited to the above structure as long as the connection structure is a layer structure that does not block the current flow in the direction in which the current flows. For example, even if the structure between the second electrode 80 and the auxiliary wiring 330 is a multi-layer structure and has a diode characteristic in the reverse direction with respect to the direction of current flow, the second electrode 80 and the auxiliary wiring 330 may be used. If the reverse breakdown voltage of the layer having the diode characteristics in the reverse direction in the multilayer structure is lower than the voltage applied between the two, an avalanche current is generated. Therefore, the display device having the multilayer structure is also included in the present invention, and has the same effect as the display device 500 according to Embodiment 3 shown in FIG.

  The light emitting unit 90 includes at least the light emitting layer 60, the hole injection layer 40, and the electron transport layer 70 provided in the pixel opening 45, and is formed by recombination of electrons and holes injected into the light emitting layer 60. The generated light is emitted from the second electrode 80 surface side. Note that a plurality of the first electrodes 20 are provided separately corresponding to the light emitting units 90. That is, when the light emitting unit is composed of at least three subpixels such as RGB, the light emitting unit 90 and the first electrode 20 are provided separately from each other corresponding to each subpixel.

  Note that the materials of the respective components such as the substrate 310 and the light emitting layer that constitute the display device 500 are the same as those in Embodiment 1, and thus the description thereof is omitted.

  According to the present embodiment, the auxiliary wiring and the first electrode can be formed, for example, so that the auxiliary wiring and the first electrode overlap each other by providing the auxiliary wiring and the first electrode on different layers of the substrate. The area can be greatly expanded. And the area of the connection opening 335 can be expanded correspondingly. As a result, the overcurrent can be effectively suppressed by increasing the connection area between the second electrode and the connection portion made of the electron transport layer and the connection area between the auxiliary wiring and the connection portion. Furthermore, since the first electrode and the auxiliary wiring can be three-dimensionally arranged, restrictions on the shape and size of the wiring electrode can be greatly relaxed. In the above case, for example, if the conductive via connected to the electrode terminal of the driving element formed on the substrate and the auxiliary wiring do not electrically short, the auxiliary wiring may be formed on the entire surface.

  Also in the present embodiment, as in the first embodiment, the auxiliary wiring may be provided one-dimensionally or two-dimensionally at least for each light emitting pixel row and for each light emitting pixel column.

  Moreover, according to this Embodiment, since an auxiliary wiring and a 1st electrode can be arrange | positioned in three dimensions, the area of a 1st electrode can be enlarged. Thereby, the opening area of a light emission part can be expanded significantly. As a result, since the light emitting portion can emit light with a low driving voltage and a small driving current, a display device with a long lifetime and excellent reliability can be realized.

  In addition, according to the present embodiment, the first electrode and the auxiliary wiring can be made of different materials. Therefore, the auxiliary wiring is optimal according to the required resistivity, and the first electrode is optimal according to the configuration of the light emitting unit. The range of selection, such as materials, is expanded. For example, in the case of the bottom emission method, the first electrode can be formed of a transparent conductive material, and the auxiliary wiring can be formed of a metal material.

  Below, the manufacturing method of the display apparatus in Embodiment 3 of this invention is demonstrated in detail, referring drawings.

  13-15 is sectional drawing explaining the manufacturing method of the display apparatus in Embodiment 3 of this invention.

  First, as shown in FIG. 13A, Al is formed on the entire surface of the second layer 314, which is the lower layer of the substrate 310 made of a plurality of layers, using, for example, a vacuum evaporation method or a sputtering method. Then, the auxiliary wiring 330 is formed at a predetermined position by etching Al using a photolithography method. At this time, the auxiliary wiring 330 is formed to be arranged one-dimensionally or two-dimensionally, for example, along a row or a column of the light emitting units arranged in a two-dimensional matrix. Further, in particular, in the case of the top emission method, auxiliary wiring may be formed at an arbitrary position as long as a short circuit or the like does not occur with a drive circuit that drives each light emitting unit.

  Next, as shown in FIG. 13B, a first layer 312 which is the uppermost layer of the substrate is formed of an oxide film such as silicon by using, for example, a CVD method or a sputtering method. At this time, the surface of the first layer 312 is preferably planarized by, for example, a CMP method.

  Next, as shown in FIG. 13C, first, Al is formed on the entire surface of the first layer 312 by using, for example, a vacuum deposition method or a sputtering method. Then, Al is etched using a photolithography method to form the first electrode 20 at a predetermined position. Thereafter, for example, PEDOT or the like to be the hole injection layer 40 is formed at a position corresponding to at least the pixel opening on the first electrode 20 by using, for example, an inkjet method.

  Next, as illustrated in FIG. 13D, a resist film 115 is formed in which openings are formed at positions that are to be connection openings 335 formed along the auxiliary wiring 330 at positions different from the first electrodes 20. .

  Next, as shown in FIG. 13E, the hole injection layer 40 and the first layer 312 are etched through the opening of the resist film 115. As a result, the auxiliary wiring 330 is exposed.

  Next, as shown in FIG. 14A, a negative photoresist 50A is applied to the entire surface. Then, the mask 110 having a light shielding portion is positioned and placed on the negative photoresist 50 </ b> A at a position corresponding to the pixel opening 45 and the connection opening 335. Then, the photoresist 50A is exposed through the mask 110 using a photolithography method.

  Next, as shown in FIG. 14B, the mask 110 is removed, and a curing process is performed to form the partition wall 50 that forms the pixel opening 45 and the connection opening 335.

  Next, as shown in FIG. 14C, a paste material to be a light emitting layer is applied in the pixel opening 45 by using, for example, an ink jet method. At this time, the paste material that becomes the light emitting layer is applied in a state of rising from the pixel opening 45 due to surface tension.

  Next, as shown in FIG. 14D, the paste material is dried, for example, at 80 ° C. for about 30 minutes, and the solvent component of the paste material is volatilized to form the light emitting layer 60 of the light emitting section. At this time, in the case where the light emitting unit is composed of at least three different sub-pixels such as RGB, the light emission of the different light emitting units for each sub-pixel is performed by repeating FIG. 14C and FIG. 14D for each sub-pixel. Pixels with layers are formed.

  Next, as shown in FIG. 15A, the electron transport layer 70 is formed using, for example, a vacuum deposition method so as to cover at least the pixel opening 45 and the connection opening 335. As a result, a connection portion that is electrically connected to a part of the upper surface of the auxiliary wiring is formed in the connection opening 335.

  Next, as shown in FIG. 15B, for example, indium tin oxide or the like is formed on the electron transport layer 70 by using a sputtering method to form the second electrode 80. Thereby, the second electrode 80 and the auxiliary wiring 330 are electrically connected via the electron transport layer 70.

  After that, as in Embodiment 1, for example, a protective layer is formed by providing a resin layer, glass, or the like, and the display device 500 is manufactured.

  According to the display device manufacturing method of the present embodiment, the same effects as those of the first embodiment can be obtained.

  Further, according to the method for manufacturing the display device of the present embodiment, the connection area between the second electrode and the auxiliary wiring can be further increased by providing the auxiliary wiring and the first electrode in different layers of the substrate. As a result, a current density can be reduced, a buffering effect against overcurrent can be further improved, fluctuations in driving voltage can be suppressed, and a display device with high display quality with little luminance variation can be manufactured with high productivity.

  In addition, according to the manufacturing method of the display device of the present embodiment, since the auxiliary wiring and the first electrode can be three-dimensionally arranged, the area of the first electrode can be increased and the opening area of the light emitting unit can be greatly increased. As a result, since light can be emitted with a low driving voltage and a small driving current, a display device with a long lifetime and excellent reliability can be manufactured.

  Further, according to the manufacturing method of the display device of the present embodiment, since the first electrode and the auxiliary wiring can be formed of different materials, the auxiliary wiring has a required resistivity, and the first electrode has a light emitting portion. An optimum material can be arbitrarily selected according to the configuration. As a result, a display device with a high degree of freedom in selecting materials can be easily manufactured.

  In addition, it is preferable that the film-forming process of the electron carrying layer 70 described in FIG. 15A and the film-forming process of the second electrode 80 described in FIG. 15B are continuous dry processes. . By making the series of processes from the film forming step of the electron transport layer 70 to the film forming step of the second electrode 80 the continuous dry process, the manufacturing process is simplified. In addition, since an unnecessary oxide layer or the like is suppressed from being interposed at the interface between the electron transport layer 70 and the second electrode 80, it contributes to high luminous efficiency, low driving voltage, and long life of the display device. .

  In the present embodiment, the hole injection layer / light emitting layer / electron transport layer has been described as an example of the configuration of the light emitting unit, but is not limited thereto. For example, it may have a configuration including at least one of a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer having a light emitting structure other than the light emitting layer. In addition to the electron transport layer, at least one of an electron injection layer, a hole injection layer, and a hole transport layer as a connection portion interposed between the second electrode and the auxiliary wiring, corresponding to the configuration of the light emitting portion. One layer may be provided. That is, the connection portion may have a laminated structure such as an electron transport layer, an electron injection layer, a hole injection layer, and a hole transport layer.

  In this case, it is preferable that the connecting portion is configured so that a current flowing from the second electrode toward the auxiliary wiring does not have a reverse diode characteristic.

  However, for example, when a hole injection layer and an electron transport layer are stacked as a connection portion, a case where a current flowing from the second electrode toward the auxiliary wiring has diode characteristics in the reverse direction is assumed. . Even in this case, an avalanche current is generated from the second electrode toward the auxiliary wiring when the reverse breakdown voltage of the diode characteristics in the reverse direction of the stacked structure is lower than the voltage applied to the connection portion. Therefore, the display device having the above laminated structure is also included in the present invention, and has the same effect as the display device 500 according to Embodiment 3 shown in FIG.

  On the other hand, when the reverse breakdown voltage of the reverse direction diode characteristic of the stacked structure is lower than the voltage applied to the connection portion, the current path from the second electrode toward the auxiliary wiring is interrupted, and the light emission Therefore, the current path is also cut off. Such a laminated structure is incompatible with the present invention.

  That is, the combination is arbitrary as long as it is a layer structure that does not block the current flowing in the connection portion with respect to the current flowing in the light emitting portion.

  In this embodiment, the display device having a partition is described as an example. However, the present invention is not limited to this. For example, in FIG. 13E, the light emitting layer may be applied only to the pixel openings by providing a layer that repels the paste material of the light emitting layer in a region other than the hole injection layer 40. This eliminates the need for a partition formation step, and can further improve productivity.

  FIG. 16 is a cross-sectional view of main parts of a display device showing a first modification example according to Embodiment 3 of the present invention. FIG. 16 is a cross-sectional view taken along the line A-A ′ of FIG. 12A in the same manner as FIG. FIG. 17 is a cross-sectional view illustrating the method for manufacturing the display device according to the first modification example of the third embodiment of the present invention. A display device 550 illustrated in FIG. 16 includes a substrate 310, a first electrode 20, an auxiliary wiring 330, a hole injection layer 40, a partition wall 50, a light emitting layer 60, an electron transport layer 70, a second layer. An electrode 80.

  The substrate 310 includes a plurality of layers, and includes a first layer 312 and a second layer 314. The display device 550 illustrated in FIG. 16 is different from the display device 400 illustrated in FIG. 12B in that the hole injection layer 40 is formed in a region other than the connection opening 335 of the auxiliary wiring 330. The configuration is different. Note that the planar layout of the display device 550 is the same as the planar layout of the display device 400 illustrated in FIG.

  Further, the display device 550 is manufactured by the following method. Note that the manufacturing method of the display device 550 is basically the same as the manufacturing method of the display device 400, and different processes are mainly described, and description of the same processes may be omitted.

  First, as shown in FIG. 17A, the auxiliary wiring 330 is formed at a predetermined position on the second layer 314 in the substrate composed of a plurality of layers.

  Next, as shown in FIG. 17B, a first layer 312 which is the uppermost layer of the substrate is formed of an oxide film such as silicon by using, for example, a CVD method or a sputtering method. At this time, the surface of the first layer 312 is preferably planarized by, for example, a CMP method.

  Next, as shown in FIG. 17C, a transition metal oxide such as molybdenum oxide, tungsten oxide, and vanadium oxide, which becomes the hole injection layer 40, is formed on the entire surface by, for example, sputtering. Film.

  Next, as shown in FIG. 17D, a resist film 115 having an opening formed at a position to be a connection opening 335 formed along the auxiliary wiring 330 is formed.

  Next, as shown in FIG. 17E, the hole injection layer 40 and the first layer 312 are etched through the opening of the resist film 115. As a result, the auxiliary wiring 330 is exposed.

  Thereafter, although the description is omitted, the display device 550 is manufactured by the same method as in FIGS. 14A to 15B.

  Thereby, since a positive hole injection layer can be formed in a lump, productivity improves. In addition, a hole injection layer having a uniform thickness can be easily formed, and display variations can be suppressed.

  In the display device 550 described above, the hole injection layer 40 made of a transition metal is described as being formed in a region other than the connection opening, but photolithography is performed only on the first electrode 20 as in the display device 500. The hole injection layer 40 may be formed using a method.

(Embodiment 4)
Hereinafter, a display device according to Embodiment 4 of the present invention will be described with reference to the drawings.

  FIG. 18 is a partial cross-sectional view illustrating a main part of the display device according to Embodiment 4 of the present invention. As shown in the figure, the display device 600 includes a substrate 410 and a display unit 500A. The substrate 410 includes a base layer 405, a drive circuit layer 420 on which a drive element for driving the light emitting unit is formed, and an interlayer insulating layer 445 formed on the drive circuit layer 420. The display unit 500 </ b> A includes components other than the substrate 10 among the components in the display device 500. Display device 600 according to the present embodiment is different from the third embodiment in the configuration of the substrate. Hereinafter, description of the same points as those of the display device 500 described in Embodiment 3 will be omitted, and only different points will be described.

  The first electrode 20 is formed on the interlayer insulating layer 445.

  The auxiliary wiring 430 is formed on the base layer 405.

  The drive circuit layer 420 is formed on the base layer 405, and includes, for example, a drive element (not shown) configured by an FET such as a TFT.

  The interlayer insulating layer 445 is formed on the drive circuit layer 420. The first electrode 20 and an electrode terminal (not shown) of the drive element are connected through a conductive via 440 formed in the interlayer insulating layer 445.

  In this configuration, the first electrode 20 and the electrode terminal (not shown) of the driving element are connected via the conductive via 440 formed in the interlayer insulating layer 445, and the connection portion made of the electron transport layer 70 is connected at the connection opening 435. The second electrode 80 and the auxiliary wiring 430 are connected via each other.

  According to this embodiment mode, the active matrix display device 600 integrated with the drive circuit layer 420 can be realized with a simple configuration. In addition, it is possible to realize a display device with high display quality that suppresses inflow of overcurrent into the pixel, suppresses fluctuations in the driving voltage of the light emitting unit, and reduces variations in luminance of the light emitting unit.

  As described above, the display device and the manufacturing method thereof according to the present invention have been described based on the embodiments. However, the display device according to the present invention is not limited to the above embodiments. In the range which does not deviate from the main point of this invention with respect to another embodiment implement | achieved combining arbitrary components in Embodiment 1-4 and its modification, Embodiment 1-4, and its modification. Modifications obtained by making various modifications conceivable by a contractor and various devices incorporating the display device according to the present invention are also included in the present invention.

  In the first to fourth embodiments, the layer constituting the connection portion has been described as a part of the layer constituting the light emitting portion, but the layer constituting the connection portion is continuous with the layer constituting the light emitting portion. You don't have to. FIG. 19 is a cross-sectional view of main parts of a display device showing a sixth modification example according to Embodiment 1 of the present invention. The display device 650 in the figure is different from the display device 100 described in FIG. 1B only in that the electron transport layer 70 is divided on the central partition 50. Not only in this case, but also in the case of having the connection part separated from the light emitting part in the first to fourth embodiments, the same effects as the effects obtained in the respective embodiments are exhibited.

  Here, as in the above-described sixth modification according to the first embodiment of the present invention, when the connection portion is separated from the light emitting portion, the connection portion has a configuration different from the components of the light emitting portion. It consists of elements. In this case, although it is difficult to simplify the manufacturing process, for example, by using an electron injecting material, an electron transporting material, a hole injecting material, or a hole transporting material as the connection portion, The problem of the present invention of suppressing luminance variation while suppressing inflow of overcurrent into the pixel is solved. Furthermore, even if it is not various materials having the above-described properties, a buffer layer having a resistance value that has an overcurrent prevention effect and does not apply an excessive load to the driving voltage of the light emitting portion can be used as a connection portion. The problem of the present invention that suppresses the luminance variation while suppressing the inflow of overcurrent to the battery is solved.

  Also, for example, the display device according to the present invention is built in a thin flat TV as shown in FIG. A thin flat TV having high display quality is realized by the display device according to the present invention which has an overcurrent prevention function and luminance variations are suppressed.

  INDUSTRIAL APPLICABILITY The display device and the manufacturing method thereof according to the present invention are useful in technical fields such as televisions and personal computer displays that require high drive quality with low drive voltage, long life, and high display quality.

(A) Partial plan view for explaining a main part of the display device according to Embodiment 1 of the present invention, (b) A cross-sectional view of the main part taken along the line A-A ′ of FIG. Sectional drawing explaining the manufacturing method of the display apparatus in Embodiment 1 of this invention Sectional drawing explaining the manufacturing method of the display apparatus in Embodiment 1 of this invention Sectional drawing of the principal part of the display apparatus which shows the 1st modification concerning Embodiment 1 of this invention Sectional drawing explaining the manufacturing method of the display apparatus which shows the 1st modification concerning Embodiment 1 of this invention. The fragmentary top view explaining the principal part of the display apparatus which shows the 2nd modification concerning Embodiment 1 of this invention The fragmentary top view explaining the principal part of the display apparatus which shows the 3rd modification based on Embodiment 1 of this invention. The fragmentary top view explaining the principal part of the display apparatus which shows the 4th modification concerning Embodiment 1 of this invention Partial plan view of a display device showing a fifth modification of the first embodiment of the present invention Sectional drawing explaining the principal part of the display apparatus in Embodiment 2 of this invention Main circuit configuration diagram of display device in embodiment 2 of the present invention (A) Partial plan view for explaining a main part of the display device according to the third embodiment of the present invention, (b) A cross-sectional view of the main part taken along the line A-A ′ of FIG. Sectional drawing explaining the manufacturing method of the display apparatus in Embodiment 3 of this invention Sectional drawing explaining the manufacturing method of the display apparatus in Embodiment 3 of this invention Sectional drawing explaining the manufacturing method of the display apparatus in Embodiment 3 of this invention Sectional drawing of the principal part of the display apparatus which shows the 1st modification based on Embodiment 3 of this invention. Sectional drawing explaining the manufacturing method of the display apparatus which shows the 1st modification concerning Embodiment 3 of this invention. Sectional drawing explaining the principal part of the display apparatus in Embodiment 4 of this invention Sectional drawing of the principal part of the display apparatus which shows the 6th modification based on Embodiment 1 of this invention. External view of thin flat TV incorporating the display device of the present invention Cross-sectional view of a light-emitting pixel included in a conventional display device described in Patent Document 1

Explanation of symbols

10, 210, 310, 410, 710 Substrate 20, 720 First electrode 30, 32, 330, 430, 730 Auxiliary wiring 35, 335, 435 Connection opening 40 Hole injection layer 45 Pixel opening 50, 740 Partition 50A Photo Resist 60 Light emitting layer 70 Electron transport layer 75 Electron injection layer 80, 760 Second electrode 90 Light emitting part 95, 96, 97, 98, 99 Light emitting pixel 100, 150, 200, 250, 300, 350, 400, 500, 550, 600, 650, 700 Display device 100A, 500A Display unit 110 Mask 115 Resist film 220, 420 Drive circuit layer 230, 445 Interlayer insulating layer 240, 440 Conductive via 312 First layer 314 Second layer 405 Base layer 745 Opening 750 Light Modulation layer

Claims (20)

A display device in which a plurality of light emitting pixels are arranged,
A substrate,
A first electrode formed on or in the substrate;
An auxiliary wiring formed to be electrically insulated from the first electrode;
A light emitting part formed on the first electrode and emitting light according to an electric current;
A second electrode formed on at least the upper surface of the light emitting unit;
A connecting portion for electrically connecting the second electrode and at least a part of the upper surface of the auxiliary wiring;
The light emitting unit
Including any one of a light emitting layer and at least an electron injection layer, an electron transport layer, a hole injection layer and a hole transport layer,
The connecting portion is
A display device comprising at least one of an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer other than the light emitting layer. The connecting portion has a multilayer structure,
The display device according to claim 1, wherein the multilayer structure has reverse diode characteristics, and a reverse breakdown voltage of a layer having the reverse diode characteristics with respect to a voltage applied to the connection portion is low. The connecting portion is
The display device according to claim 1, wherein the display device does not have a diode characteristic in a reverse direction between the second electrode and the auxiliary wiring. The substrate has at least a first layer and a second layer different from the first layer,
The first electrode is formed on the first layer;
The display device according to claim 1, wherein the auxiliary wiring is formed on the second layer. At least one of the electron injection layer, the electron transport layer, the hole injection layer, and the hole transport layer included in the connection portion,
The display device according to claim 1, wherein the display device is formed continuously over the light emitting unit and the connection unit. In the display device, the plurality of light emitting pixels are arranged in a matrix.
The first electrode and the light emitting unit are provided to be separated at least for each light emitting pixel,
The display device according to claim 1, wherein the auxiliary wiring is disposed at least in each of the light emitting pixel columns and in each of the light emitting pixel rows. Each of the plurality of light emitting pixels includes at least three sub-pixels,
The first electrode and the light emitting unit are provided separately for each sub-pixel,
The display device according to claim 6, wherein the auxiliary wiring is arranged at least for each of the sub-pixel columns and for each of the sub-pixel rows. Each of the plurality of light emitting pixels includes at least three sub-pixels,
The first electrode and the light emitting unit are provided separately for each sub-pixel,
The display device according to claim 6, wherein the auxiliary wiring is disposed at least for each of the light emitting pixel columns and for each of the light emitting pixel rows. The display device according to claim 1, wherein the electron transport layer includes at least one of an alkali metal, an alkaline earth metal, and a compound thereof. The substrate further comprises:
An interlayer insulating layer disposed under the first electrode;
A driving circuit layer disposed under the interlayer insulating layer and having a driving element for driving the light emitting pixels;
The display device according to claim 1, wherein the first electrode and the driving element are connected via a conductive via provided in the interlayer insulating layer. The drive element comprises a thin film transistor,
The display device according to claim 10, wherein the first electrode is connected to a source terminal or a drain terminal of the driving element through the conductive via. A method of manufacturing a display device in which a plurality of light emitting pixels are arranged,
A first forming step of forming a first electrode and an auxiliary wiring electrically insulated from the first electrode on or in the substrate;
On the first electrode, includes a light emitting layer and at least one of an electron injection layer, an electron transport layer, a hole injection layer, and a hole transport layer, and a light emitting portion that emits light in response to an electric current, and on the auxiliary wiring A second forming step of forming at least an electron injection layer, an electron transport layer, a hole injection layer, and a connection portion including any one of the hole transport layers, and
And a third forming step of forming a second electrode on at least the light emitting portion and the connecting portion after the second forming step. In the second forming step,
The connecting portion has a multilayer structure,
The display device according to claim 12, wherein the multilayer structure has reverse diode characteristics, and a reverse breakdown voltage of a layer having the reverse diode characteristics with respect to a voltage applied to the connection portion is low. Method. In the second forming step,
The connecting portion is
The method for manufacturing a display device according to claim 12, wherein the second electrode and the auxiliary wiring do not have reverse diode characteristics. The substrate has at least a first layer and a second layer different from the first layer,
In the first forming step,
Forming the first electrode on the first layer;
The method for manufacturing a display device according to claim 12, wherein the auxiliary wiring is formed on the second layer. In the second forming step,
Any one of the electron injection layer, the electron transport layer, the hole injection layer, and the hole transport layer formed on the auxiliary wiring is continuously formed over the connection portion and the light emitting portion. The manufacturing method of the display apparatus of any one of Claims 12-15. In the second forming step,
The display device according to claim 16, wherein at least one of the electron injection layer, the electron transport layer, the hole injection layer, and the hole transport layer formed on the auxiliary wiring is formed on the entire surface by a vacuum deposition method. Manufacturing method. At least one of the electron injection layer, the electron transport layer, the hole injection layer, and the hole transport layer formed on the auxiliary wiring in the second formation step, and the second in the third formation step. The method for manufacturing a display device according to claim 12, wherein the electrode is formed by a continuous dry process. In the second forming step,
The method for manufacturing a display device according to claim 12, wherein the electron transport layer includes at least one of an alkali metal, an alkaline earth metal, and a compound thereof. Before the first forming step,
A driving layer forming step of forming a driving circuit layer having a driving element for driving the light emitting pixels as a constituent layer of the substrate;
The insulating layer formation process of forming the interlayer insulation layer which has a conductive via which makes the said drive element and said 1st electrode conduct as an uppermost layer of the said board | substrate on the said drive circuit layer is included. The manufacturing method of the display apparatus of any one of them.

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