JP2011034931A - Organic el display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL device reducing a possible floating or delamination at an end of a bank, and which is easy to manufacture. <P>SOLUTION: The organic EL device 1 includes a substrate 10; an organic EL element part 20 provided on the substrate 10 and including a lower electrode 23; an organic EL layer 24 including a light-emitting layer; and an upper electrode 25, and a bank 30 partitioning the organic EL element part 20 by pixel units, wherein the lower electrode 23 has a base layer 21 and a coating layer 22, in this order, an end of the base layer 21 is covered by the bank 30, an end of the bank 30 is covered by the coating layer 22, and a first auxiliary wiring 26 is provided on the bank 30, and the wiring 26 which is a member formed by processing the same thin-film layer as the coating layer 22 and insulated from the coating layer 22. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an organic EL device.

  It is known that a transparent conductive film serving as an anode or a cathode has a higher film resistance than a thin film made of a metal material (see Patent Document 1). Here, when the film resistance of the transparent conductive film serving as the electrode layer is high, the in-plane potential distribution becomes non-uniform due to a voltage drop, causing a problem such as luminance variation of the light emitting element, so-called shading.

  Patent Document 1 proposes a light emitting device in which the film resistance of a transparent conductive film is reduced. Specifically, the auxiliary wiring is provided on the top surface of the first partition wall (bank) made of an insulating material that covers the end portion of the lower electrode and separates the pixels, and the same insulating material is provided on the side surface of the first partition wall. There have been proposed light emitting devices each having a structure covered by a second partition wall (bank) made of The light emitting device disclosed in Patent Document 1 not only solves the above-described film resistance problem, but also reduces the step defect of the first partition (bank) by the second partition, thereby reducing coverage defects. .

JP 2004-127933 A

  By the way, in the light emitting device disclosed in Patent Document 1, a first partition (bank) for partitioning pixels and an auxiliary wiring provided on the first partition are collectively formed by patterning using the same mask. . However, during this patterning, etching wraps around the edge of the first partition, which causes a problem that the first partition floats (floats) from the substrate. This floating problem can be solved by forming a second partition that assists the first sidewall and repairing the floating from the substrate. However, since it is necessary to newly provide a process for forming the second partition wall, the manufacturing cost is increased.

  On the other hand, when the first partition wall peels off or floats from the substrate, the peeling or floating causes, for example, a short circuit between the lower electrode and the upper electrode, resulting in the generation of non-light emitting pixels. Here, when non-light emitting pixels are generated, black spots are generated in the display area, and the display quality of the organic EL display device is deteriorated.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an organic EL device that reduces floating and peeling that may occur at the end of a bank and is easy to manufacture in order to solve the above-described problems of the prior art. Objective.

The organic EL device of the present invention includes a substrate,
An organic EL element portion provided on the substrate and comprising a lower electrode, an organic EL layer including a light emitting layer, and an upper electrode;
A bank that divides the organic EL element unit in units of pixels,
The lower electrode has a base layer and a coating layer in this order,
The edge of the foundation layer is covered by the bank;
The end of the bank is covered by the clothing layer;
A first auxiliary wiring is provided on the bank;
The first auxiliary wiring is a member processed from the same thin film layer as the coating layer, and is insulated from the coating layer.

  According to the present invention, it is possible to obtain a high-quality organic EL element that maintains and improves light emission characteristics without causing an increase in manufacturing cost.

  That is, in the present invention, the covering layer covers the end portion of the bank, so that peeling of the end portion of the bank is prevented. For this reason, it is possible to prevent the functional layers including the organic EL layer laminated on the bank from being cut off, and to form a pixel without a short defect between the lower electrode and the upper electrode or a disconnection of the upper electrode. it can. Therefore, it is possible to obtain an organic EL device free from non-lighting pixel defects.

1 is a schematic cross-sectional view showing a first embodiment in an organic EL device of the present invention. It is a section schematic diagram showing a 2nd embodiment in an organic EL device of the present invention.

  The organic EL device of the present invention includes a substrate, an organic EL element portion provided on the substrate, and a bank that partitions the organic EL element portion in units of pixels. In the organic EL device of the present invention, the organic EL element portion is a member composed of a lower electrode, an organic EL layer including a light emitting layer, and an upper electrode. The lower electrode included in the organic EL element portion is a stacked electrode layer having a base layer and a coating layer in this order.

  By the way, the edge part of the foundation | substrate layer contained in a lower electrode is covered with the bank, and the edge part of this bank is covered with the clothing layer contained in a lower electrode. On the other hand, a first auxiliary wiring used when driving the organic EL device is provided on the bank. Here, the first auxiliary wiring is a member processed from the same thin film layer as the coating layer, and is insulated from the coating layer.

  Hereinafter, embodiments of a display device according to the present invention will be described with reference to the drawings. Note that well-known or publicly-known techniques in the technical field can be applied to portions that are not particularly illustrated or described in the present specification. The embodiment described below is only one of the embodiments, and the present invention is not limited thereto.

  FIG. 1 is a schematic cross-sectional view showing a first embodiment of the organic EL device of the present invention. 1 basically includes a substrate 10, an organic EL element portion 20 provided on the substrate 10, and a bank 30 that partitions the organic EL element portion 20 provided on the substrate 10 in units of pixels. And. Note that the organic EL device 1 shown in FIG. 1 can emit one pixel in a single color. In addition, the organic EL device 1 of FIG. 1 can perform color display including R light emission, G light emission, and B light emission by controlling light emission of each pixel by three pixels having different light emission colors.

  The substrate 10 is a member composed of a base material 11 such as a glass base material, and an insulating layer 12 and a planarization layer 13 that are sequentially stacked on the base material 11.

  In the insulating layer 12, a thin film transistor (TFT) 14 is formed for each pixel. In the organic EL device 1 of FIG. 1, one TFT is described for each pixel. However, a plurality of TFTs necessary for controlling the driving of the organic EL element unit 20 such as a current control TFT and a drive control TFT. One type of TFT can be provided for each pixel.

  The planarization layer 13 is provided in order to flatten the unevenness generated when the TFT 14 is formed. The planarization layer 13 is provided with two types of contact holes (15, 16) at predetermined positions. Here, the contact hole 15 is provided to electrically connect the TFT 14 and the source-side extraction electrode 18. On the other hand, the contact hole 16 is provided to electrically connect the TFT 14 and the drain-side extraction electrode 19.

  On the planarizing layer 13, the above-described two kinds of extraction electrodes (18, 19), the lower electrode 23, the second auxiliary wiring 27, and the bank 30 are provided at predetermined positions. The positional relationship and electrical connection relationship of these members will be described below.

  The lower electrode 23 is a laminated electrode layer having a base layer 21 and a covering layer 22 in this order. The underlayer 21 is electrically connected to the drain-side extraction electrode 19. For this reason, the base layer 21 is electrically connected to the TFT 14. The end portion of the base layer 21 is covered with the bank 30. On the other hand, the covering layer 22 is in contact with an organic EL layer 24 described later, and a part of the covering layer 22 covers an end of the bank 30. In the present invention, from the viewpoint of improving the adhesion between the coating layer 22 and the organic EL layer 24, the coating layer 22 is preferably thinner than the base layer 21.

  The periphery of the second auxiliary wiring 27 is covered with the bank 30. The second auxiliary wiring 27 is patterned so as to cross between the pixels, and is electrically connected to the extraction electrode 18 on the source side. Therefore, the base layer 21 is electrically connected to the second auxiliary wiring 27 via the TFT 14. Therefore, the lower electrode 23 functions to drive the organic EL device by an electric signal transmitted from the second auxiliary wiring 27. Further, the light emission control of the organic EL element unit 20 of each pixel is performed by controlling the current applied to the organic EL layer 24 sandwiched between the lower electrode 23 including the base layer 21 and the upper electrode 25. . The second auxiliary wiring 27 is preferably a member processed from the same thin film layer as the base layer 21. By forming from the same thin film layer, the manufacturing cost is reduced, the aperture ratio of the organic EL device is improved, and a stable current can be supplied to the lower electrode 23. On the other hand, the second auxiliary wiring 27 is insulated from the base layer 21 from the viewpoint of preventing a short circuit.

  The bank 30 is a member made of an insulating material, and is provided so as to cover the second auxiliary wiring 27 and the two kinds of lead electrodes (18, 19). That is, the second auxiliary wiring 27 and two kinds of lead electrodes (18, 19) are built in the bank 30. The bank 30 covers the end portion of the base layer 21, while the end portion is covered with the covering layer 22. In this way, by providing the covering layer 22 so as to cover the end portion of the bank 30, damage that may occur at the end portion of the bank 30 when the second auxiliary wiring 27 is formed (during patterning formation) can be reduced. . This prevents peeling or floating of the end of the bank 30 that occurs when the damage to the bank 30 is large when the second auxiliary wiring 27 is formed. Further, short circuit between the upper electrode 25 and the lower electrode 23 due to the peeling or floating is prevented. For this reason, it is possible to prevent the occurrence of defects in the display region and to prevent a reduction in the yield of the display device.

  On the other hand, a first auxiliary wiring 26 is provided on the upper surface of the bank 30. The first auxiliary wiring 26 is patterned so as to cross between the pixels, and functions as a potential line of the upper electrode 25 serving as a common electrode. The first auxiliary wiring 26 is also connected to a contact line (not shown) provided outside the display area. A common potential is supplied to the upper electrode 25 via the first auxiliary wiring 26 via a connection terminal (not shown) electrically connected to the contact line. In the configuration of the present embodiment, since the first auxiliary wiring 26 is electrically connected to the upper electrode 25, the potential gradient of the upper electrode 25 in the display region (not shown) can be suppressed to a small value. That is, in the configuration of the present embodiment, shading can be kept small, and the display quality of the organic EL device can be improved.

  In the organic EL device of the present invention, the first auxiliary wiring 26 is a member processed from the same thin film layer as the coating layer 22. For this reason, since the process of forming the covering layer 22 and the process of forming the first auxiliary wiring 26 are not performed separately, an increase in the manufacturing cost of the display device due to an increase in the number of processes is prevented, and a decrease in the yield of the manufacturing process is prevented. be able to. Further, since the first auxiliary wiring 26 and the covering layer 22 are members processed from the same thin film layer, the current allowable amount of the upper electrode 25 can be increased. The first auxiliary wiring 26 is insulated from the coating layer 22 in order to prevent a short circuit with the coating layer 22.

  On the other hand, in the organic EL device of the present invention, as shown in FIG. 1, auxiliary wirings (26, 27) are formed in the bank 30 and on the upper surface of the bank 30, respectively. For this reason, it is not necessary to secure a planar / spatial area necessary for arranging the auxiliary wiring separately from the bank 30, so that it is possible to prevent a decrease in the aperture ratio of the pixel due to formation of the auxiliary wiring.

  The organic EL layer 24 which is a constituent member of the organic EL element unit 20 is a single layer thin film including a light emitting layer or a laminated body including a plurality of layers. The organic EL layer 24 is not particularly limited as long as it includes a light emitting layer. For example, in addition to the light emitting layer, any one of a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer may be included. A layer having a plurality of functions may be provided.

  The upper electrode 25 that is a constituent member of the organic EL element unit 20 is electrically connected to the first auxiliary wiring 26 as described above. For example, the upper electrode 25 and the first auxiliary wiring 26 are connected on the bank 30 as shown in FIG. An embodiment is mentioned. However, the manner of electrical connection between the upper electrode 25 and the first auxiliary wiring 26 is not limited to this. For example, the upper electrode 25 may be formed on the entire surface of the organic EL device, particularly the light emitting region thereof, and all the first auxiliary wirings 26 and the upper electrode 25 may be electrically connected. Alternatively, a pattern of the upper electrode 25 may be formed so that the upper electrode 25 is individually provided for each pixel and electrically connected to any one of the first auxiliary wirings 26. Furthermore, the upper electrode 25 may be provided as a partial common electrode for a plurality of arbitrarily selected pixels and electrically connected to the corresponding first auxiliary wirings 26.

  The organic EL device of the present invention is appropriately provided with a sealing layer 41 and a protective film 42 in order to protect the organic EL element unit 20 from moisture and oxygen in the atmosphere. In addition, specific examples of the constituent materials of the sealing layer 41 and the protective film 42 and specific formation methods will be described later.

  Next, a specific method for manufacturing the organic EL device of this embodiment will be described.

First, the substrate 10 having the TFTs 14 is prepared. Here, the board | substrate 10 is produced at the process shown below, for example. In addition, when performing following (a)-(d), a well-known method can be used.
(A) Step of forming TFT 14 on substrate 11 (b) Step of forming insulating layer 12 (c) Step of forming flattening layer 13 (d) Contact hole 15 in a predetermined region of flattening layer 13, Step of providing 16

  Examples of the constituent material of the insulating layer 12 and the planarizing layer 13 include photosensitive and insulating resin materials such as photosensitive polyimide resin and photosensitive acrylic resin. A preferred method for forming the planarizing layer 13 is specifically a method of forming a photosensitive polyimide resin with a film thickness of about 2 μm. A specific method for providing the contact holes 15 and 16 by the step (d) includes patterning (pattern removal) by mixed acid wet etching after resist application.

  Next, a source-side extraction electrode 18 is formed in the contact hole 15, and a drain-side extraction electrode 19 is formed in the contact hole 16. The two kinds of lead electrodes (18, 19) are formed of a conductive material. The two kinds of lead electrodes (18, 19) play a role of electrically connecting the TFT 14 and the lower electrode 23. For this reason, a material having low contact resistance and high adhesion to both the TFT 14 and the lower electrode 23 is selected as a constituent material of the two kinds of lead electrodes (18, 19). Also, the formation process is appropriately selected from the viewpoint of reducing the contact resistance and improving the adhesion to both the TFT 14 and the lower electrode 23. The drain-side extraction electrode 19 is not particularly limited in its shape (pattern shape) as long as electrical connection with the lower electrode 23 is maintained. For example, it may be connected to a part of the lower electrode 23, the drain-side extraction electrode 19 is formed larger than the lower electrode 23, and the lower electrode 23 is formed on the pattern of the extraction electrode 19. May be.

  As a constituent material of the extraction electrodes (18, 19), a conductive material can be cited. In addition, since the extraction electrodes (18, 19) are formed in the contact holes (15, 16) having a tapered cross section, a material having a low reflectance is preferable from the viewpoint of suppressing external light reflection. It is not limited. As the constituent material of the extraction electrodes (18, 19), for example, a transparent conductive film such as ITO, IZO, ZnO, or the like, or a thin film formed of a metal such as Cr, Al, Ag, Au, or Pt in a thickness range of 50 nm to 150 nm. Etc. As a preferred method for forming the extraction electrodes (18, 19), specifically, a method of forming a film of ITO with a film thickness of about 50 nm and then patterning it into a desired shape by a known method can be mentioned.

Next, the bank 30 and the organic EL element unit 20 are formed on the substrate 10. In the present invention, the steps of forming the bank 30 and the organic EL element portion 20 include the following steps (1) to (5).
(1) A step of forming a first layer of the lower electrode on the substrate (2) A step of processing the first layer of the lower electrode to form a base layer and a second auxiliary wiring portion (3) A bank is formed (4) forming a lower electrode second layer on the bank or the underlying layer (5) processing the lower electrode second layer to form a covering layer and a first auxiliary wiring portion

  Hereinafter, a specific method for forming the bank 30 and the organic EL element unit 20 will be described. First, a lower electrode first layer is formed on a substrate. The constituent material of the first layer of the lower electrode is not particularly limited as long as the electrode material has high reflectivity and conductivity. Examples of the constituent material of the first layer of the lower electrode include metal materials such as Cr, Al, Ag, Au, and Pt. Among these metal materials, a metal material having a high reflectance is more preferable because light extraction efficiency can be improved. The film thickness of the first layer of the lower electrode is preferably about 50 nm to 300 nm. Note that an adhesion layer (not shown) for improving the adhesion to the planarization layer 13 may be formed before the first lower electrode layer is formed. As a preferable method for forming the first layer of the lower electrode, specifically, a method of forming a film of Ag with a film thickness of about 150 nm can be given.

  Next, the first layer of the lower electrode is processed to form the base layer 21 and the second auxiliary wiring portion 27. Examples of the forming method include patterning by a photo process. For example, patterning is preferably performed so that the wiring width of the second auxiliary wiring portion 27 is about 10 μm. In addition, when performing patterning formation, it patterns so that the base layer 21 and the 2nd auxiliary wiring part 27 may insulate.

  Further, for the purpose of improving the injectability of electrons or holes into the organic EL layer 24, a potential control layer (not shown) may be formed on the base layer 21 after the patterning is completed. Further, an interfacial adhesion layer (not shown) may be laminated on the surface of the base layer 21 or the coating layer 22 described later. The interfacial adhesion layer is a thin film having a function of improving the interfacial adhesion between the base layer 21 and the coating layer 22 or improving the efficiency of injecting holes or electrons with the organic light emitting material laminated on the coating layer 22. Is a layer. As a constituent material of the interface adhesion layer, for example, a transparent conductive material such as ITO, IZO, ZnO, a metal material such as Al, Cr, W, Mo, Ti, Cu, or an alloy obtained by mixing a plurality of these metal materials, an alkali metal A metal alloy containing can be used. As a suitable method for forming the interfacial adhesion layer, specifically, a method of forming ITO with a film thickness of 50 nm can be mentioned.

  Next, the bank 30 is formed so as to cover the end portion of the base layer 21 and the second auxiliary wiring portion 27. Examples of the constituent material of the bank 30 include photosensitive and insulating resin materials such as a photosensitive polyimide resin and a photosensitive acrylic resin. The bank 30 is formed in a desired pattern by, for example, applying and forming the resin material on the base layer 21 and the second auxiliary wiring portion 27 and processing (pattern formation) by a photolithography process. In addition, as a suitable formation method of the application / film formation step of the resin material, specifically, there is a method of forming a film of a photosensitive polyimide resin with a film thickness of about 2 μm.

  Next, the lower electrode second layer is formed on the bank 30 or the base layer 21, and then the lower electrode second layer is processed to form the covering layer 22 and the first auxiliary wiring portion 26, respectively. Here, the same material as the constituent material of the first layer of the lower electrode can be used as the constituent material of the second layer of the lower electrode. As a preferred method for forming the second lower electrode layer, specifically, a method of forming a film of Ag with a film thickness of about 100 nm can be given.

  As the processing method of the second electrode of the lower electrode, the same method as the processing method of the first layer of the lower electrode can be used. For example, patterning is preferably performed so that the wiring width of the first auxiliary wiring portion 26 is about 10 μm. When patterning is performed as in the case of the first layer of the lower electrode, patterning is performed so that the covering layer 22 and the first auxiliary wiring portion 26 are insulated.

  As described above, the underlying layer 21 and the second auxiliary wiring 27 constituting the lower electrode 23 and the covering layer 22 and the first auxiliary wiring 26 constituting the lower electrode 23 are formed from a common electrode thin film, respectively. There is no need to add a new process for forming the auxiliary wiring. Further, since the lower electrode second layer is processed so that the end portion of the bank 30 is covered with the covering layer 22, the end portion of the bank 30 is not damaged when the lower electrode second layer is processed. It is possible to prevent the bank 30 from being lifted or peeled off. Further, by preventing the bank 30 from being lifted or peeled off, it is possible to prevent the organic EL layer 24 to be laminated later from being disconnected or the occurrence of a short circuit between the upper electrode 25 and the lower electrode 23.

  Next, the organic EL layer 24 is formed on the coating layer 22. When the organic EL layer 24 is formed, the organic EL layer 24 is formed so that the surface of the first auxiliary wiring 26 is exposed so that the first auxiliary wiring 26 and the upper electrode 25 are electrically connected. For example, there is a method of forming the organic EL layer 24 by painting using a mask. Alternatively, the first auxiliary wiring 26 that is electrically connected to the upper electrode 25 is formed after the laminated body that becomes the organic EL layer 24 is formed so as to cover the covering layer 22, the bank 30, and the first auxiliary wiring 26. For the portion, there is a method of removing the laminate by laser processing.

  As a constituent material of the organic EL layer 24, at least one selected from an organic light emitting material, a hole injection material, an electron injection material, a hole transport material, and an electron transport material can be used. Also, a hole injection material or a hole transport material doped with an organic light emitting material, or an electron injection material or an electron transport material doped with an organic light emitting material can be used. By doping an organic light emitting material into the charge injection / transport material, the range of color selection can be expanded. On the other hand, the organic EL layer 24 is preferably an amorphous film from the viewpoint of luminous efficiency.

  As the organic light emitting material, triarylamine derivatives, stilbene derivatives, polyarylenes, aromatic condensed polycyclic compounds, aromatic heterocyclic compounds, aromatic heterocyclic condensed compounds, metal complex compounds, and the like can be used. Moreover, these single oligo bodies or composite oligo bodies can be used. However, the present invention is not limited to these exemplified materials.

  As the hole injection / transport material, phthalocyanine compounds, triarylamine compounds, conductive polymers, perylene compounds, Eu complexes, and the like can be used, but the present invention is not limited to these exemplified materials.

As an electron injecting / transporting material, Alq ₃ in which a trimer of 8-hydroxyquinoline is coordinated to an aluminum ion, an azomethine zinc complex, a distyryl biphenyl derivative system, or the like can be used.

  As a method for forming the organic EL layer 24, a method such as a vacuum deposition method or a transfer method can be appropriately selected according to the constituent material of the organic EL layer 24. Moreover, the film thickness of the organic EL layer 24 is preferably 50 nm to 300 nm, and more preferably 50 nm to 150 nm.

  Next, the upper electrode 25 is formed on the bank 30, the first auxiliary wiring portion 26 and the organic EL layer 24, and the first auxiliary wiring 26 and the upper electrode 25 are electrically connected. In the organic EL device of the present invention, the upper electrode 25 functions as a light extraction electrode for outputting the light emitted from each pixel to the outside of the device. For this reason, the constituent material of the upper electrode 25 includes a conductive material having a high transmittance. For example, a transparent conductive film such as ITO, IZO, or ZnO can be used. Alternatively, a semi-transmissive film in which a metal such as Ag, Au, or Al is formed in the range of 10 nm to 30 nm may be used. On the other hand, a method of forming the upper electrode 25 includes a vacuum sputtering method.

  After forming the upper electrode 25, the sealing layer 41 and the protective layer 42 are sequentially formed, whereby the organic EL display device of FIG. 1 is obtained.

  The material and form of the sealing layer 41 are not particularly limited as long as the organic EL element part 20 that is sensitive to moisture and oxygen can be protected from moisture and oxygen in the atmosphere. For example, an inorganic passivation film such as SiN, SiO, or SiON, a highly moisture-proof resin film, an engraved glass substrate provided with a hygroscopic material, or the like can be preferably used.

  The protective layer 42 is provided for the purpose of protecting the sealing layer 41 and preventing a decrease in contrast due to external light reflection. In the present invention, the protective layer 42 may have a function as a polarizing plate or an antireflection film. As the protective layer 42, for example, an acrylic plate, a PET resin plate or the like can be used.

  According to the configuration of the present embodiment described above, the light emission current to each pixel can be stably supplied to the lower electrode 23 by the second auxiliary wiring 27 electrically connected to the lower electrode 23. On the other hand, the voltage gradient of the upper electrode 25 in the display area can be kept small in the upper electrode 25 by the second auxiliary wiring 27 electrically connected to the upper electrode 25. Further, according to the configuration of the present embodiment, two types of auxiliary wiring (26, 27) can be formed simultaneously with the constituent members of the lower electrode 23. For this reason, it is not necessary to newly provide a process for forming the two types of auxiliary wiring (26, 27). Further, since the two types of auxiliary wirings (26, 27) are provided with the auxiliary wirings (26, 27) inside or on the upper surface of the bank 30, it is possible to prevent a reduction in the aperture ratio of the device. Therefore, it is possible to provide an organic EL display device excellent in manufacturability and high definition.

  FIG. 2 is a schematic cross-sectional view showing a second embodiment of the organic EL device of the present invention. Hereinafter, the difference from Example 1 will be mainly described.

  The organic EL device 2 of FIG. 2 is newly provided with a subbank 31 in the organic EL device 1 of FIG. As shown in FIG. 2, the subbank 31 is provided so as to cover the end of the coating layer 22 and the bank 30. However, as in the first embodiment, in order to ensure electrical connection between the first auxiliary wiring 26 and the upper electrode 25, a part of the thin film that becomes the subbank 31 is processed. Specifically, a process of partially removing the thin film covering at least the first auxiliary wiring 26 is performed to expose the first auxiliary wiring 26.

  As the constituent material of the sub-bank 31, the same material as the constituent material of the bank 30 can be used, but a black matrix material may be used. Further, the subbank 31 may be a functional layer for preventing the bank 30 from being peeled off due to the substrate cleaning. As a preferable method for forming the thin film to be the subbank 31, specifically, a method of forming a photosensitive polyimide resin with a film thickness of about 2 μm can be given. On the other hand, examples of the processing method of the subbank 31 include processing by a photolithography process, laser processing, and the like.

  By forming the subbank 31 in advance before forming the organic EL layer 24, the organic EL layer 24 can be processed by patterning or the like without damaging the bank 30 or the coating layer 22. Further, by providing the sub-bank 31, the end of the bank 30 is more reliably protected, so that damage due to patterning can be suppressed, which contributes to prevention of device yield reduction. However, in addition to this, it is possible to prevent breakage of the organic EL layer 24 stacked on the bank 30 and occurrence of a short circuit between the upper electrode 25 and the lower electrode 23.

  As described above, the organic EL display device according to the present embodiment can suppress the voltage gradient of the upper electrode 25 in the display region as in the first embodiment. In addition, the sub-bank 31 can be processed in a state where the floating of the end of the bank 30 is suppressed. Therefore, it is possible to provide an organic EL display device which is excellent in manufacturability and high definition and has a good quality.

  1: Organic EL device, 10: Substrate, 20: Organic EL element part, 21: Underlayer, 22: Cover layer, 23: Lower electrode, 24: Organic EL layer, 25: Upper electrode, 26: First auxiliary wiring part , 30: Bank

Claims (5)

A substrate,
An organic EL element portion provided on the substrate and comprising a lower electrode, an organic EL layer including a light emitting layer, and an upper electrode;
A bank that divides the organic EL element unit in units of pixels,
The lower electrode has a base layer and a coating layer in this order,
The edge of the foundation layer is covered by the bank;
The end of the bank is covered by the clothing layer;
A first auxiliary wiring portion is provided on the bank;
The organic EL device, wherein the first auxiliary wiring is a member processed from the same thin film layer as the coating layer and is insulated from the coating layer. A second auxiliary wiring is further provided on the substrate,
2. The organic EL device according to claim 1, wherein the second auxiliary wiring is a member processed from the same thin film layer as the base layer and is insulated from the base layer.   3. The organic EL device according to claim 1, wherein a film thickness of the coating layer is thinner than a film thickness of the base layer.   The organic EL element according to claim 1, wherein an end portion of the covering layer is covered with an insulating thin film layer. The method for manufacturing an organic EL device according to claim 1, wherein the following steps (1) to (5) are included.
(1) A step of forming a first layer of the lower electrode on the substrate (2) A step of processing the first layer of the lower electrode to form a base layer and a second auxiliary wiring portion (3) A bank is formed (4) forming a lower electrode second layer on the bank or the underlying layer (5) processing the lower electrode second layer to form a covering layer and a first auxiliary wiring portion

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