JP2010026350A - Top emission type organic el display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a top emission type organic EL (electroluminescent) display device capable of reducing inclination of luminance on screen without increasing the dimension of a frame region. <P>SOLUTION: In the top emission type organic EL display device, a sealing substrate 40 is stuck onto an element substrate 10 having many pixels through a sealing material 50 formed in its peripheral part. In the pixel, an organic EL layer is nipped and held between a lower electrode and an upper electrode 23. The upper electrode 23 exists up to an end part of the element substrate 10 on an outer side of the sealing material 50. A power supply line 60 formed by electrical conductive paste is connected with the upper electrode 23 on the outer side of the sealing material 50 to prevent electric potential of the upper electrode 23 from dropping and suppress inclination of luminance. Since the power supply line 60 is formed on the outer side of the sealing material 50, the dimension of a frame can be reduced. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an organic EL display device, and more particularly to a top emission type organic EL display device having a uniform screen luminance and a small frame area around the display area.

  In the organic EL display device, light emitted from the organic EL layer is extracted in the direction opposite to the glass substrate on which the organic EL layer is formed, and the bottom emission type in which the light is emitted toward the glass substrate on which the organic EL layer is formed. There is a top emission type. The top emission type has an advantage that the brightness of the display can be increased because a large area of the organic EL layer can be taken.

  In an organic EL display device, an organic EL layer is sandwiched between a lower electrode and an upper electrode, a constant voltage is applied to the upper electrode, and a data signal voltage is applied to the lower electrode to control light emission of the organic EL layer. Form an image. The data signal voltage is supplied to the lower electrode through a thin film transistor (TFT). In the top emission type organic EL display device, since the organic EL layer can be formed on the TFT and the like, the light emission area can be increased.

  In the organic EL display device, it is necessary to supply a current from the upper electrode to the organic EL layer. Since the top emission type organic EL display device needs to extract light through the upper electrode, the upper electrode must be transparent. As the transparent electrode, there are ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), ZnO (zinc oxide), SnO (tin oxide), etc., but these metal oxide conductive films have high resistance.

  The upper electrode is formed by vapor deposition or sputtering in common over the entire display region. When the resistance of the upper electrode is large, the potential in the vicinity of the terminal portion that supplies power to the upper electrode is different from the potential in the portion far from the terminal portion, causing a luminance gradient in the display area. That is, a phenomenon occurs in which a portion near the terminal portion is bright and a portion far from the terminal portion is dark.

  “Patent Document 1” describes a configuration for reducing the resistance of the upper electrode. That is, in the organic EL display device, an element substrate on which an organic EL layer or the like is formed and a sealing substrate for protecting the organic EL layer from moisture are opposed to the element substrate through a sealing material formed in the periphery. Arranged. In “Patent Document 1”, in order to reduce the voltage drop of the upper electrode, a power supply line is also formed in parallel on the sealing substrate side.

Japanese Patent Laid-Open No. 11-354272

  The technology described in “Patent Document 1” forms an electrode for assisting the upper electrode on the sealing substrate or the sealing cap. In this case, the top emission type organic EL display device may cause unevenness of screen luminance. There is. Further, although power is supplied to the element substrate, a structure for electrical connection from the element substrate to the sealing substrate is necessary.

  In order to reduce the resistance of the upper electrode, the film thickness of the upper electrode may be increased. However, when the film thickness of the upper electrode is increased, light from the organic EL layer is absorbed by the upper electrode in the top emission. As a result, there arises a problem that the brightness of the screen is lowered. Therefore, in order to reduce the voltage drop in the upper electrode, a power line is arranged around the display area, and the power line around the display area is used as an auxiliary for the upper electrode to reduce the voltage drop in the upper electrode. ing.

  On the other hand, in a small-sized liquid crystal display device used for a mobile phone, a DSC (Digital Still Camera) or the like, there is a strong demand for reducing the outer shape while maintaining a predetermined area of the image display area. Then, it is necessary to reduce the frame size around the display area.

  However, if the power supply line is arranged around the display area, the frame size becomes large, and the above-mentioned demand cannot be met. An object of the present invention is to realize a configuration capable of reducing the outer shape of an organic EL display device while keeping a predetermined display area area while keeping a luminance gradient of a screen small.

  The present invention solves the above-mentioned problems, and specific means are as follows.

  (1) An element having a pixel in which an organic EL layer is sandwiched between a lower electrode and an upper electrode, a power supply line for supplying current to the upper electrode, and a terminal portion for supplying current to the power supply line from the outside A top emission type organic EL display device, wherein a sealing substrate is disposed opposite to the substrate and the element substrate, and a peripheral portion of the element substrate and the sealing substrate is bonded and sealed with a sealing material, the upper electrode Extends through the lower part of the sealing material to the end of the element substrate, and the upper electrode is connected to the power line on the outside of the sealing material.

  (2) The upper electrode and the power line existing outside the sealing material are connected to each other at a side other than the side where the terminal portion of the element substrate is formed. Top emission type organic EL display device.

  (3) The upper electrode and the power line existing outside the sealing material are connected to each other on a side of the element substrate opposite to a side where the terminal portion is formed ( A top emission type organic EL display device according to 1).

  (4) The top emission type organic EL display device according to (1), wherein the power supply line is formed by applying a metal fine particle paste.

  (5) The top emission type organic EL display device according to (1), wherein the power line is formed by applying a graphite paste.

  (6) A plurality of pixels in which the organic EL layer is sandwiched between the lower electrode and the upper electrode are formed, a bank is formed between the pixels, and the upper electrode is connected to the bank. An auxiliary electrode made of metal is formed, a power supply line for supplying a current to the upper electrode, an element substrate having a terminal portion for supplying a current to the power supply line from the outside, and a seal facing the element substrate. A top emission type organic EL display device in which a stop substrate is disposed, and a peripheral portion of the element substrate and the sealing substrate is bonded and sealed with a sealing material, wherein the upper electrode passes through a lower portion of the sealing material and the element A top emission type organic EL display device, which extends to an end portion of a substrate, and wherein the upper electrode is connected to the power supply line outside the sealing material.

  (7) The upper electrode and the power line existing outside the sealing material are connected to each other at a side other than the side where the terminal portion of the element substrate is formed. Top emission type organic EL display device.

  (8) An element having a pixel in which an organic EL layer is sandwiched between a lower electrode and an upper electrode, a power supply line for supplying current to the upper electrode, and a terminal portion for supplying current to the power supply line from the outside A top emission organic EL display device in which a protective film is formed by covering a substrate and the element substrate, wherein the upper electrode is formed up to an end of the element substrate, and the protective film is formed on the element substrate. The upper electrode is not covered with the protective film at the outermost periphery, and the power line covers the upper electrode and connects to the upper electrode at the outermost periphery. A top emission type organic EL display device.

  (9) The top according to (8), wherein the power line covers the upper electrode and is connected to the upper electrode, except for the side where the terminal portion of the element substrate is formed. Emission type organic EL display device.

  (10) The top emission organic EL display device according to (8), wherein the power line is formed by applying a conductive paste by printing.

  According to the present invention, in the top emission type organic EL display device, the upper electrode is extended to the outside of the sealing material, and the power supply line and the sealing material are connected to the outside of the sealing material. The brightness gradient of the screen can be suppressed.

  The contents of the present invention will be described below in detail according to examples.

  FIG. 1 is a cross-sectional view of a pixel portion of a top emission type organic EL display device to which the present invention is applied. The top emission type organic EL display device includes a top anode type in which an anode is present on the organic EL layer 22 and a top cathode type in which a cathode is present on the organic EL layer 22. Although FIG. 1 shows a case of a top anode type, the present invention can be similarly applied to a case of a top cathode.

In FIG. 1, on the element substrate 10 and the first base film 11 made of SiN, the second base film 12 made of SiO ₂ is formed. This is to prevent impurities from the glass substrate from contaminating the semiconductor layer 13. A semiconductor layer 13 is formed on the second base film 12. The semiconductor layer 13 is converted to a poly-Si film by laser irradiation after an a-Si film is formed by CVD.

A gate insulating film 14 made of SiO ₂ is formed so as to cover the semiconductor layer 13. A gate electrode 15 is formed in a portion facing the semiconductor layer 13 with the gate insulating film 14 interposed therebetween. Using the gate electrode 15 as a mask, an impurity such as phosphorus or boron is implanted into the semiconductor layer 13 by ion implantation to impart conductivity, thereby forming a source portion or a drain portion in the semiconductor layer 13.

An interlayer insulating film 16 is formed of SiO ₂ so as to cover the gate electrode 15. This is because the gate wiring and the drain electrode 17 are insulated. A drain electrode 17 is formed on the interlayer insulating film 16. The drain electrode 17 is connected to the drain portion of the semiconductor layer 13 through the interlayer insulating film 16 and the through hole 65 of the gate insulating film 14.

  Thereafter, an inorganic passivation film 18 made of SiN is deposited to protect the TFT. An organic passivation film 19 is formed on the inorganic passivation film 18. The organic passivation film 19 has a role of protecting the TFT more completely together with the inorganic passivation film 18 and a function of flattening the surface on which the organic EL layer 22 is formed. Therefore, the organic passivation film 19 is formed as thick as 1 to 4 μm.

  A reflective electrode is formed of Al or an Al alloy on the organic passivation film 19. Since Al or Al alloy has a high reflectance, it is suitable as a reflective electrode. The reflective electrode is connected to the drain electrode 17 through a through hole 65 formed in the organic passivation film 19 and the inorganic passivation film 18.

  Since this embodiment is a top anode type organic EL display device, the lower electrode 21 of the organic EL layer 22 serves as a cathode. Therefore, Al or an Al alloy used as the reflective electrode can also serve as the lower electrode 21 of the organic EL layer 22. This is because Al or an Al alloy has a relatively small work function and can function as a cathode.

  In the case of the top cathode type, since the lower electrode 21 serves as an anode, ITO is used for the lower electrode 21. Further, in order to increase the light extraction efficiency from the organic EL layer 22, a reflective electrode is formed under the ITO which is the lower electrode 21. In this case, the reflective electrode is made of Al or Al alloy having good reflectivity. Due to the presence of the reflective electrode, the light emitted from the organic EL layer 22 is emitted in the direction of the white arrow L in FIG.

  An organic EL layer 22 is formed on the lower electrode 21. The organic EL layer 22 is formed by a plurality of layers. In this embodiment, an electron injection layer, an electron transport layer, a light emitting layer, and a hole transport layer are formed from the lower layer. A hole injection layer may be provided between the hole transport layer and the upper electrode 23 in some cases. An upper electrode 23 serving as an anode is formed on the organic EL layer 22. In this embodiment, IZO is used as the upper electrode 23. IZO is deposited on the entire display region 100 without using a mask. The thickness of IZO is formed to be about 30 nm in order to maintain the light transmittance. IZO has a lower resistance than ITO when not annealed.

  The organic EL layer 22 is composed of a plurality of layers, and the configuration is as follows. The electron transporting layer is not particularly limited as long as it exhibits electron transporting properties and can be easily formed into a charge transfer complex by co-evaporation with an alkali metal. Quinolinolato) aluminum, bis (2-methyl-8-quinolinolato) -4-phenylphenolate-aluminum, bis [2- [2-hydroxyphenyl] benzoxazolate] zinc and other metal complexes and 2- (4-biphenylyl) ) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole, 1,3-bis [5- (p-tert-butylphenyl) -1,3,4-oxadiazole- 2-yl] benzene or the like can be used.

  The electron injection layer is formed by co-evaporation of a material having an electron donating property with respect to the substance used for the electron transport layer, for example, an alkali metal such as lithium and cesium, an alkaline earth metal such as magnesium and calcium, and They may be selected from metals such as rare earth metals, or their oxides, halides, carbonates, etc., and used as substances exhibiting electron donating properties.

  The hole transport layer includes, for example, a tetraarylbenzidine compound (triphenyldiamine: TPD), an aromatic tertiary amine, a hydrazone derivative, a carbazole derivative, a triazole derivative, an imidazole derivative, an oxadiazole derivative having an amino group, a polythiophene derivative, Copper phthalocyanine derivatives and the like can be used.

  The light emitting layer material is not particularly limited as long as it can be formed as a light emitting layer by co-evaporation by adding a dopant that emits fluorescence or phosphorescence by recombination to a host material having electron and hole transport capability. For example, tris (8-quinolinolato) aluminum, bis (8-quinolinolato) magnesium, bis (benzo {f} -8-quinolinolato) zinc, bis (2-methyl-8-quinolinolato) aluminum oxide, tris ( 8-quinolinolato) indium, tris (5-methyl-8-quinolinolato) aluminum, 8-quinolinolatolithium, tris (5-chloro-8-quinolinolato) gallium, bis (5-chloro-8-quinolinolato) calcium, 5 , 7-dichloro-8-quinolinolato aluminum, tris ( , 7-dibromo-8-hydroxyquinolinolato) aluminum, poly [zinc (II) -bis (8-hydroxy-5-quinolinyl) methane] -like complexes, anthracene derivatives, carbazole derivatives, and the like. .

  In addition, the dopant captures electrons and holes in the host to recombine and emits light. For example, a red light emitting substance such as a pyran derivative, a green coumarin derivative, a blue anthracene derivative, or an iridium complex. Further, a phosphorescent substance such as a pyridinate derivative may be used.

  The upper electrode 23 as the uppermost layer needs to be a transparent conductive film in order to extract light. In this embodiment, the upper electrode 23 is IZO, but another transparent conductive film may be used in consideration of the light transmittance and the electric resistance. Furthermore, since a metal film made of Au, Ag, or the like becomes thin when it is thinned, it can be used as the upper electrode 23 in some cases.

  In addition, in order to prevent the organic EL layer 22 from being broken at the end portion due to disconnection, the bank 20 is formed between the pixels. The bank 20 may be formed of an organic material or an inorganic material such as SiN. When using an organic material, it is generally formed of an acrylic resin.

  The upper electrode 23 is formed on the entire display region 100 of the organic EL display device, such as on the organic EL layer 22 and the bank 20, by vapor deposition or sputtering. A sealing substrate 40 made of glass is installed on the upper electrode 23 with a space in between. Since the luminous efficiency of the organic EL layer 22 decreases when moisture is present, the sealing substrate 40 is disposed to protect it from moisture. The sealing substrate 40 is bonded to the TFT substrate and the sealing material 50 at the end. The organic EL layer 22 formed on the element substrate 10 by the sealing substrate 40 and the sealing material 50 is protected from moisture.

  FIG. 2 is a plan view of the organic EL display device according to this embodiment. In FIG. 2, the element substrate 10 and the sealing substrate 40 are bonded to each other by a sealing material 50 to protect the organic EL layer 22 formed on the element substrate 10 from moisture. The sealing material 50 is formed of, for example, an epoxy resin. A display area 100 is formed inside the sealing material 50. A desiccant (not shown) is disposed on the element substrate 10 between the display region 100 and the sealing material 50.

  The element substrate 10 is formed larger than the sealing substrate 40, and a terminal portion 70 is formed on the lower side in FIG. 2 where the element substrate 10 is a single sheet. The terminal unit 70 is provided with an IC driver (not shown) for driving the organic EL display panel in addition to a terminal connected to a flexible wiring board for connecting to an external circuit.

  The feature of FIG. 2 is that the upper electrode 23 is formed even outside the sealing material 50 that bonds the element substrate 10 and the sealing substrate 40 together. Then, a power line 60 is formed outside the sealing material 50, and current is supplied from the power line 60 to the upper electrode 23. Since the power supply line 60 can be formed thick, the voltage drop of the upper electrode 23 due to the current flowing can be suppressed, and the luminance gradient of the screen can be suppressed.

  The power supply line 60 is supplied from the terminal unit 70 of FIG. Since the power supply line 60 is arranged on the surface, power can be supplied directly from a flexible wiring board or the like, or current can be supplied from the flexible wiring board or the like to a layer formed in the same layer as the drain layer, so that a through hole is formed. A current may be supplied to the power supply line 60 via the power supply line 60. Since the through hole in this case is formed in the terminal portion 70, the outer shape of the organic EL display panel is not increased.

  2 is formed on the outer side of the long side of the sealing material 50 and on the outer side of the short side of the sealing material 50 on the side opposite to the terminal portion 70. In FIG. 2, the power supply line 60 is not disposed on the short side on the terminal side. However, as long as there is no hindrance to the connection of the flexible wiring board or the like in the terminal portion 70, the power supply line 60 may be arranged on the short side on the terminal portion 70 side.

  3 is a cross-sectional view taken along the line AA in FIG. In FIG. 3, the element substrate 10 on which the organic EL layer 22 and the like are formed and the sealing substrate 40 are bonded via a sealing material 50 formed in the periphery. In FIG. 3, the upper electrode 23 is formed on the element substrate 10. In FIG. 3, the configuration below the upper electrode 23 is omitted. The upper electrode 23 in FIG. 3 is formed so as to cover the entire display region 100, and further exists outside the sealing material 50. The upper electrode 23 is made of IZO. However, since IZO is a metal oxide and is a chemically stable material, there is no problem in reliability even if it exists outside the sealing material 50.

  In FIG. 3, a power supply line 60 is disposed in a portion where IZO which is the upper electrode 23 extends outside the sealing material 50. Since the power supply line 60 is not related to the light transmission of the display region 100, it can be formed thick. Further, the power line 60 does not have to be a transparent electrode. By forming the power supply line 60 thick, the resistance of the power supply line 60 is lowered and the voltage drop of the upper electrode 23 is suppressed.

  As a material of the power supply line 60 in FIG. 3, a conductive paste such as a silver paste can be used. Silver paste is an epoxy resin in which fine particles of silver are dispersed, and can reduce resistance. Silver paste can be formed by coating. The epoxy that is the base material (organic medium) of the silver paste may be an ultraviolet curable type or a thermosetting type. In the case of the thermosetting type, it is necessary to use a material that cures at 100 ° C. or lower. This is because the organic EL layer 22 is destroyed at a high temperature.

  As a material of the power supply line 60 in FIG. 3, Ni paste, Al paste, etc. can be used in addition to silver paste. Ni paste is obtained by dispersing Ni fine particles in an organic medium. Further, the Al paste is obtained by dispersing Al fine particles in an organic medium. Silver paste, Ni paste, Al paste, etc. are called metal fine particle paste.

  Further, a graphite paste can be used as a material for the power supply line 60. As graphite, graphite is preferable because of its low resistivity. Graphite paste is chemically very stable. In addition, since graphite and the like have very fine particles, they can enter fine irregularities and pinholes, so that stable conduction can be obtained.

  Although the organic medium of the above conductive paste is epoxy, it is not limited to epoxy, and acrylic resin, phenol resin, silicon resin, or the like can be used. However, these resins are required to be ultraviolet curable or materials that can be thermally cured at 100 ° C. or lower.

  FIG. 4 is an enlarged view of a corner portion of FIG. In FIG. 4, a display region 100 indicated by a dotted line is formed inside the sealing material 50. The upper electrode 23 exists even outside the sealing material 50. A power line 60 is formed on the outer side of the sealing material 50 so as to overlap the upper electrode 23. The power supply line 60 is formed so as to surround the periphery of the panel. Therefore, the entire periphery of the display region 100 can be maintained at substantially the same potential.

  Another feature of FIG. 4 is that the so-called frame dimension f, which is the dimension from the end of the display region 100 to the end of the organic EL display panel, can be reduced. That is, in the present invention, the power supply line 60 is disposed outside the seal member 50, and the power supply line 60 is disposed outside the seal portion, which has not been conventionally used. Therefore, it is possible to omit the width of the power supply line 60 and the through hole 65 for connecting the power supply line 60 and the upper electrode 23 required in the conventional configuration described later.

  5 to 7 are conventional examples as comparative examples for the present invention. FIG. 5 is a plan view of a conventional example. In FIG. 5, the element substrate 10 and the sealing substrate 40 are bonded via a sealing material 50. A display area 100 indicated by a dotted line is formed inside the sealing material 50. The upper electrode 23 is solid and has a slightly larger area than the display area 100. In order to alleviate the change in potential of the upper electrode 23, the power line 60 extends outside the display region 100 and inside the sealing material 50. A current to the power supply line 60 is supplied from the terminal unit 70.

  6 is a cross-sectional view taken along line BB in FIG. In FIG. 6, the element substrate 10 on which the organic EL layer 22 and the like are formed and the sealing substrate 40 are bonded via a sealing material 50 formed in the periphery. In FIG. 6, the upper electrode 23 is formed on the element substrate 10. In FIG. 6, the configuration below the upper electrode 23 is omitted. The upper electrode 23 in FIG. 6 is formed in a slightly larger area than the display region 100.

  A power line 60 is formed in the periphery of the upper electrode 23 inside the sealing material 50. In FIG. 6, the upper electrode 23 is described as directly overlapping the power supply line 60, but actually, an insulating film such as an inorganic passivation film and an organic passivation film is provided between the power supply and the upper electrode 23. Existing. Therefore, the power supply line 60 and the upper electrode 23 are connected via the through hole 65 formed in the inorganic passivation film and the organic passivation film.

  FIG. 7 is an enlarged view of a corner portion of FIG. In FIG. 7, a display region 100 indicated by a dotted line is formed inside the sealing material 50. The upper electrode 23 is formed in an area slightly larger than the display region 100 inside the sealing material 50. The power line 60 is formed so as to overlap the end portion of the upper electrode 23. In FIG. 7, the power supply line 60 is formed in the same layer as the drain electrode. Therefore, in order to conduct with the upper electrode 23, it is necessary to form the through hole 65 in the inorganic passivation film and the organic passivation film formed above the power supply line 60.

  Therefore, in the configuration of FIG. 7, it is necessary to secure a space for the power supply line 60 and the through hole 65 inside the sealing material 50 outside the display region 100. For this reason, the frame dimension f, which is the dimension from the end of the display region 100 to the end of the organic EL display panel, is larger than that of the configuration of FIG. 4 according to the present invention.

  As described above, according to the present invention, the voltage drop of the upper electrode 23 can be suppressed, and the inclination of the screen luminance can be suppressed. And since the power supply line 60 for suppressing a brightness | luminance inclination is formed in the outer side of the sealing material 50 which was not used conventionally, the width | variety of a frame can be restrained small.

  In the configuration of the embodiment, since the power supply line 60 is formed around the organic EL display panel, the inclination of the luminance on the top and bottom or the left and right of the screen can be suppressed. However, in the configuration of the first embodiment, the luminance difference between the periphery of the screen and the center of the screen still exists. That is, since the power supply line 60 having a sufficiently small resistance is formed around the screen by coating, the luminance around the screen can be made almost constant. However, since the current is supplied to the center of the screen from the periphery of the screen, if the resistance of the upper electrode 23 is large, the potential is different between the periphery of the screen and the center of the screen, resulting in a luminance gradient.

  FIG. 8 provides such a configuration that suppresses the luminance gradient between the periphery of the screen and the center of the screen. In FIG. 8, a red pixel 101, a green pixel 102, and a blue pixel 103 are arranged in the vertical direction. In FIG. 8, a bank 20 is formed between pixels. The interval s between the pixels in the vertical direction of the pixels, that is, the width of the bank 20 is 25 μm to 30 μm.

  In FIG. 8, the auxiliary electrode 30 is extended in the horizontal direction at the portion of the vertical pixel-to-pixel spacing s to suppress the voltage drop of the upper electrode 23. The width w of the auxiliary electrode 30 is 10 μm to 15 μm. Since the auxiliary electrode 30 is formed on the bank 20, it can be formed thick. Moreover, since it does not need to be transparent, Al or Al alloy with low resistivity is used.

  9 is a cross-sectional view taken along the line AA in FIG. The configuration in FIG. 9 is the same as the configuration described in FIG. 1 except for the auxiliary electrode 30. In FIG. 9, the auxiliary electrode 30 is formed on the bank 20. The auxiliary electrode 30 can suppress the voltage drop of the upper electrode 23 only by being formed on the upper electrode 23. Therefore, even if the upper electrode 23 is formed, the advantage of the present invention that the size of the frame portion can be reduced can be enjoyed.

  In Example 1 and Example 2, in order to protect the organic EL layer 22 from moisture, the sealing substrate 40 is used, and the sealing substrate 40 and the element substrate 10 are bonded together by the sealing material 50 in the periphery, and moisture from the outside Preventing the intrusion of In this embodiment, the present invention is applied to a configuration in which the organic EL is protected from moisture without using the sealing substrate 40.

FIG. 10 shows a third embodiment of the present invention. In FIG. 10, an organic EL layer 22 (not shown) is formed in the display region 100 of the element substrate 10. An upper electrode 23 is formed on the organic EL layer 22 by IZO. The upper electrode 23 is formed on the entire surface of the element substrate 10 except for the terminal portion 70. A protective film 200 indicated by a one-dot chain line is formed so as to cover the upper electrode 23. The protective film 200 protects the organic EL layer 22 from moisture from the outside air. Protective film 200 is formed by SiO ₂ or SiN, or both. In addition, organic materials that cure at low temperatures may be used.

  The protective film 200 is formed up to the outermost periphery of the element substrate 10. In the outermost periphery, the upper electrode 23 is not covered with the protective film 200. However, metal oxides such as IZO are chemically stable, and there is no problem in reliability even if they are not covered with the protective film 200. On the outermost periphery, the power line 60 is formed by coating in a portion where the upper electrode 23 is not covered with the protective film 200. The protective film 200 need not be formed up to the terminal portion 70. This is because the scanning line or video signal line extending to the terminal portion 70 is protected by the inorganic passivation film and the organic passivation film.

  The power supply line 60 in FIG. 10 can also use a conductive paste such as a silver paste or a graphite paste as described in the first embodiment. Since the power supply line 60 in FIG. 10 is formed on the element substrate 10, it can be easily formed by printing. The power supply line 60 extends to the terminal portion 70 and receives supply of current from the terminal portion 70. The method of supplying current in the terminal unit 70 is the same as that described in the first embodiment.

  11 is a cross-sectional view taken along the line DD of FIG. In FIG. 11, the upper electrode 23 is formed on the entire element substrate 10. In FIG. 11, the lower layer than the upper electrode 23 is omitted. In FIG. 11, a protective film 200 is formed on the upper electrode 23. The protective film 200 is not formed up to the outermost periphery of the element substrate 10.

  On the outermost periphery, a power line 60 is formed in a portion where the upper electrode 23 is not covered with the protective film 200. The power line 60 is in direct contact with the upper electrode 23. In this case, the power supply line 60 can be easily formed by printing.

  In the present embodiment, the upper electrode 23 exists outside the protective film 200, and the power supply line 60 is directly applied to the protective film 200 by printing or the like, thereby suppressing the voltage drop in the upper electrode 23, and the screen. The luminance gradient can be suppressed. Also in the third embodiment, the influence of the luminance gradient can be further reduced by using the auxiliary electrode 30 as described in the second embodiment.

It is sectional drawing of an organic electroluminescence display. It is a top view of the organic electroluminescence display of this invention. It is AA sectional drawing of FIG. It is a corner part enlarged view of FIG. It is a top view of the organic electroluminescence display of a prior art example. It is BB sectional drawing of FIG. It is a corner part enlarged view of FIG. FIG. 10 is a plan view of a display area in Example 2. It is CC sectional drawing of FIG. 6 is a plan view of an organic EL display device according to Example 3. FIG. It is DD sectional drawing of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Element substrate, 11 ... 1st base film, 12 ... 2nd base film, 13 ... Semiconductor layer, 14 ... Gate insulating film, 15 ... Gate electrode, 16 ... Interlayer insulating film, 17 ... Drain electrode, 18 ... Inorganic passivation Membrane, 19 ... Organic passivation film, 20 ... Bank, 21 ... Lower electrode, 22 ... Organic EL layer, 23 ... Upper electrode, 30 ... Auxiliary electrode, 40 ... Sealing substrate, 50 ... Sealing material, 60 ... Power line, 65 DESCRIPTION OF SYMBOLS ... Through-hole 70 ... Terminal part 100 ... Display area 101 ... Red pixel 102 ... Green pixel 103 ... Blue pixel 200 ... Protective film

Claims (10)

A pixel in which an organic EL layer is sandwiched between a lower electrode and an upper electrode; a power supply line for supplying power to the upper electrode; an element substrate having a terminal portion for supplying power to the power supply line from outside; and the element substrate; A top emission type organic EL display device in which a sealing substrate is disposed oppositely and the peripheral portion of the element substrate and the sealing substrate is bonded and sealed with a sealing material,
The top electrode extends to the end of the element substrate through the portion of the sealing material, and the top electrode is connected to the power line on the outside of the sealing material. Display device.   2. The top emission according to claim 1, wherein the upper electrode and the power line existing outside the sealing material are connected to each other at a side other than the side where the terminal portion of the element substrate is formed. Type organic EL display device.   The upper electrode and the power line existing outside the sealing material are connected to each other on a side of the element substrate opposite to a side where the terminal portion is formed. The top emission type organic EL display device described.   2. The top emission type organic EL display device according to claim 1, wherein the power line is formed by applying a metal fine particle paste.   The top emission type organic EL display device according to claim 1, wherein the power line is formed by applying a graphite paste. A plurality of pixels in which an organic EL layer is sandwiched between a lower electrode and an upper electrode are formed, a bank is formed between the pixels, and an auxiliary by a metal connected to the upper electrode is formed on the bank. An electrode is formed, a power supply line for supplying power to the upper electrode, an element substrate having a terminal portion for supplying power to the power supply line from the outside, and a sealing substrate disposed opposite the element substrate, A top emission type organic EL display device in which a peripheral portion of an element substrate and the sealing substrate is bonded and sealed with a sealing material,
The top electrode extends to the end of the element substrate through the portion of the sealing material, and the top electrode is connected to the power line on the outside of the sealing material. Display device.   The top emission according to claim 6, wherein the upper electrode and the power supply line existing outside the sealing material are connected to each other at a side other than the side where the terminal portion of the element substrate is formed. Type organic EL display device. A pixel in which an organic EL layer is sandwiched between a lower electrode and an upper electrode, a power supply line for supplying power to the upper electrode, an element substrate having a terminal portion for supplying power to the power supply line from the outside, and the element substrate Then, a top emission type organic EL display device in which a protective film is formed,
The upper electrode is formed up to the end of the element substrate, and the protective film is not formed on the outermost periphery of the element substrate, and the upper electrode is covered with the protective film on the outermost periphery. The top emission type organic EL display device is characterized in that, on the outermost periphery, the power line covers the upper electrode and is connected to the upper electrode.   9. The top emission organic material according to claim 8, wherein the power line covers the upper electrode and is connected to the upper electrode at a side other than the side where the terminal portion of the element substrate is formed. EL display device.   9. The top emission type organic EL display device according to claim 8, wherein the power line is formed by applying a conductive paste by printing.

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