JP5682328B2 - Electro-optical device, method of manufacturing electro-optical device, and electronic apparatus - Google Patents

Description

  The present invention relates to an electro-optical device, a method for manufacturing the electro-optical device, and an electronic apparatus including the light-emitting device.

  In recent years, with the diversification of information equipment, the need for flat display devices that consume less power and are lighter is increasing. As one of such flat display devices, an organic EL device having a light emitting layer is known. Such an organic EL device generally has a configuration in which a light emitting layer is provided between an anode and a cathode. Furthermore, in order to improve the hole injection property and the electron injection property, a configuration in which a hole injection layer is arranged between the anode and the light emitting layer and a configuration in which an electron injection layer is arranged between the light emitting layer and the cathode are proposed. ing.

Many materials used for the light-emitting layer, hole injection layer, electron injection layer, and cathode of an organic EL device are likely to react with moisture in the atmosphere and easily deteriorate. When these layers deteriorate, a non-light emitting region called a dark spot is formed in the organic EL device, and the lifetime as a light emitting element is shortened. Therefore, in such an organic EL device, it is a problem to suppress the influence of moisture, oxygen and the like.
In order to solve such a problem, a method of preventing the intrusion of moisture and oxygen by bonding a sealing member made of glass or metal to a substrate of an organic EL device has been generally adopted. However, as the display becomes larger, thinner, and lighter, it has become difficult to prevent moisture and oxygen from entering only with the bonded sealing member. In addition, in order to secure a sufficient area for forming drive elements and wirings with an increase in size, the necessity of using a top emission structure that extracts light from the sealing member side has also been proposed. In order to achieve such a demand, a sealing structure using a thin film using a thin film that is transparent, lightweight and excellent in strength resistance is required.

  Therefore, in recent years, in order to cope with an increase in size and weight of a display device, a thin film of silicon nitride, silicon oxide, ceramics, etc. that is transparent and has excellent gas barrier properties on a light emitting element is formed by a high-density plasma deposition method ( For example, a technique called thin film sealing formed as a gas barrier layer by ion plating, ECR plasma sputtering, ECR plasma CVD, surface plasma CVD, ICP-CVD, or the like is used. However, with this alone, the pixel provided with the light emitting layer has a pixel partition, and the gas barrier layer is peeled off or cracked in the unevenness (stepped portion) generated by the partition, and moisture intrusion is recognized from there. ing. Therefore, a crack is generated in the inorganic passivation film (gas barrier layer) by disposing a resin sealing film having a substantially flat upper surface below the inorganic passivation film (gas barrier layer) covering the organic EL element and the partition wall. Has been proposed (for example, Patent Document 1).

Japanese Patent Laid-Open No. 2001-284041

  However, even when such a technique is adopted, it is not possible to completely prevent moisture from entering from the outside, and there is a problem that sufficient light emission characteristics and light emission lifetime cannot be obtained. This is because the inorganic passivation film (gas barrier layer) is peeled off or cracked at steps such as the substrate wiring or the connection portion between the electrode and the substrate wiring where no resin sealing film is formed. This is because intrusion occurs. The intrusion of moisture and oxygen does not affect only the light-emitting element, but it reaches the cathode or anode electrode, causing an effect such as an increase in electrical resistance or swelling of the thin film electrode. And reduce the luminous life.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  [Application Example 1] An electro-optical device according to this application example is provided on a first substrate, a first wiring, a first electrode, a partition having an opening corresponding to the first electrode, and the first electrode. An organic functional layer, a second electrode provided on the partition wall and the organic functional layer, a connection portion for electrically connecting the second electrode and the first wiring, and the second electrode A buffer layer provided on the buffer layer, and a gas barrier layer provided on the buffer layer, wherein the second electrode includes a first region covering the partition wall, and a second region provided in the connection portion. And the buffer layer includes a first buffer layer covering the first region, and a second buffer layer covering the second region, and the first buffer layer The second buffer layer is not in contact with each other.

  According to this application example, since the buffer layer covers the step formed by the partition wall or the step generated by the connection portion, the step surface becomes substantially flat, and the gas barrier layer is formed on the substantially flat buffer layer. It is possible to prevent the peeling of the layer and the occurrence of cracks, and as a result, it is possible to prevent the light emission characteristics and the light emission life from being lowered. Further, by covering the buffer layer separately from the step formed by the partition wall and the step generated by the connecting portion, a defect or the like occurs in the gas barrier layer in the step portion where one buffer layer is formed, and moisture enters. However, it is possible to prevent moisture from entering the other buffer layer.

  Application Example 2 In the electro-optical device according to the application example described above, the second wiring is provided on the base, and the third buffer layer is provided on the second wiring in a plan view. The first buffer layer, the second buffer layer, and the third buffer layer are not in contact with each other.

  According to the above application example, since the buffer layer can cover the step formed by the wiring, it is possible to effectively prevent peeling of the gas barrier layer and generation of a crack at the step.

  Application Example 3 In the electro-optical device according to the application example, the second wiring is a wiring for driving and controlling a light emitting element having the first electrode, the organic functional layer, and the cathode. Features.

  According to the above application example, the buffer layer covers the step formed by the wiring for driving and controlling the light emitting element, so that the gas barrier layer can be effectively prevented from being peeled off and cracks generated at the step.

  Application Example 4 In the electro-optical device according to the application example, the buffer layer is made of an organic material, and the gas barrier layer is made of an insulating inorganic compound.

  According to the above application example, since the buffer layer is an organic material, it can be thickened and flattened. Further, since the gas barrier layer is an insulating inorganic compound, a barrier property against moisture and oxygen can be obtained even with a thin film. Accordingly, since the gas barrier layer can be formed on the flat buffer layer, the gas barrier layer can be prevented from being peeled off or cracked.

  Application Example 5 In the electro-optical device according to the application example described above, a protective layer that covers the second electrode is provided between the second electrode and the gas barrier layer.

  According to the application example, by providing the protective layer on the second electrode, when the buffer layer is formed on the second electrode, the external force applied to the second electrode that is a thin film is reduced, and the second electrode is peeled off. The occurrence of defects such as cracks can be prevented.

  Application Example 6 In the electro-optical device according to the application example, the protective layer is made of an insulating inorganic compound.

  According to the above application example, since the protective layer is made of an insulating inorganic compound, a protective layer having a high elastic modulus can be formed on the second electrode with a thin film, thereby preventing problems such as peeling and cracking of the second electrode. it can.

  Application Example 7 In the electro-optical device according to the application example described above, the thickness of the buffer layer is larger than the total thickness of the second electrode and the protective layer. And

  According to the above application example, the step formed in the protective layer covering the second electrode can be flattened by the buffer layer, so that it is not necessary to flatten the step on the second electrode by the protective layer, and these are only necessary film thicknesses. It can be.

  Application Example 8 A method for manufacturing an electro-optical device according to this application example includes: a first wiring; a first electrode; a partition having an opening corresponding to the first electrode; An electro-optical device manufacturing method comprising: an organic functional layer provided on a first electrode; and a second electrode provided on the partition and the organic functional layer, wherein the second electrode and the first electrode A step of forming a connection part for electrically connecting the wiring, a step of forming a buffer layer provided on the second electrode, a step of forming a gas barrier layer provided on the buffer layer, The second electrode has a first region that covers the partition; and a second region that is provided in the connection portion; and the buffer layer covers a first region that covers the first region. 1 buffer layer and a second buffer layer covering the second region, and the step of forming the buffer layer includes Characterized in that the first buffer layer and the second buffer layer is formed so as not to contact with each other.

  According to this application example, since the buffer layer covers the step formed by the partition wall or the step generated by the connection portion, the step surface becomes substantially flat, and the gas barrier layer is formed on the substantially flat buffer layer. It is possible to prevent the peeling of the layer and the occurrence of cracks, and as a result, it is possible to prevent the light emission characteristics and the light emission life from being lowered. Further, by covering the buffer layer separately from the step formed by the partition wall and the step generated by the connecting portion, a defect or the like occurs in the gas barrier layer in the step portion where one buffer layer is formed, and moisture enters. However, it is possible to prevent moisture from entering the other buffer layer.

  Application Example 9 In the method of manufacturing the electro-optical device according to the application example, a plurality of the electro-optical devices are formed on the first substrate, and the step of forming the buffer layer includes the step of forming the buffer layer. On the one substrate, the second buffer layer is formed in common across the connecting portions of the adjacent electro-optical devices.

  According to the above application example, it is not necessary to form a buffer layer for each electro-optical device, so that the formation accuracy of the buffer layer can be relaxed. Therefore, it is possible to prevent pattern defects caused by the formation of the buffer layer.

  Application Example 10 An electronic apparatus according to this application example includes the electro-optical device described in the application example.

  According to this application example, it is possible to provide an electronic apparatus including the electro-optical device that prevents the light emission characteristics and the light emission lifetime from being lowered.

FIG. 2 is an equivalent circuit diagram showing an electrical configuration of the EL display device according to the first embodiment. 1 is a schematic plan view showing a configuration of an EL display device according to a first embodiment. Sectional drawing which follows the AB line | wire of FIG. Sectional drawing which follows the CD line | wire of FIG. The enlarged view which shows the edge part of an organic buffer layer. (A)-(d) is a figure which shows the manufacturing method of EL display apparatus in order of a process. (A)-(c) is a figure which shows the manufacturing method of EL display apparatus in order of a process. (A) And (b) is the schematic which shows the structure of EL display apparatus of 2nd embodiment. The schematic sectional drawing which shows the outer peripheral part structure of the base | substrate of EL display apparatus. (A)-(d) is a figure which shows the example of an electronic device.

  Hereinafter, embodiments of an electro-optical device, a method for manufacturing the electro-optical device, and an electronic apparatus according to the present invention will be described with reference to the drawings. In the drawings to be referred to, cross-sectional hatching is appropriately omitted in order to improve the visibility of the drawings. In addition, as an electro-optical device, an EL display device using an organic electroluminescence (EL) material will be described as an example.

[First embodiment]
FIG. 1 is an equivalent circuit diagram showing an electrical configuration of the EL display device according to the first embodiment. An EL display device (light-emitting device) is an active matrix EL display device using a thin film transistor (hereinafter abbreviated as TFT) as a switching element. In the following description, each scale is made different so that each part and each layer film constituting the EL display device can be recognized.

As shown in FIG. 1, the EL display device 1 of this embodiment includes a plurality of scanning lines 101, a plurality of signal lines 102 extending in a direction perpendicular to the scanning lines 101, and the signal lines 102. A plurality of power supply lines 103 extending in parallel are arranged, and a pixel region X is provided near each intersection of the scanning line 101 and the signal line 102.
A data line driving circuit 100 including a shift register, a level shifter, a video line, and an analog switch is connected to the signal line 102. Further, a scanning line driving circuit 80 including a shift register and a level shifter is connected to the scanning line 101.

  Further, in each pixel region X, a switching TFT 112 to which a scanning signal is supplied to the gate electrode via the scanning line 101 and a pixel signal to be supplied from the signal line 102 via the switching TFT 112 are held. A capacitor 113, a driving TFT 123 to which a pixel signal held by the holding capacitor 113 is supplied to the gate electrode, and driving from the power line 103 when electrically connected to the power line 103 through the driving TFT 123 A pixel electrode (first electrode) 23 into which a current flows and an organic functional layer 110 sandwiched between the pixel electrode 23 and a cathode (second electrode) 50 are provided. The pixel electrode 23, the cathode 50, and the organic functional layer 110 constitute a light emitting element (organic EL element).

  According to the EL display device 1, when the scanning line 101 is driven and the switching TFT 112 is turned on, the potential of the signal line 102 at that time is held in the holding capacitor 113, and according to the state of the holding capacitor 113. The on / off state of the driving TFT 123 is determined. Then, a current flows from the power supply line 103 to the pixel electrode 23 via the channel of the driving TFT 123, and further a current flows to the cathode 50 via the organic functional layer 110. The organic functional layer 110 emits light according to the amount of current flowing through it.

Next, a specific configuration of the EL display device 1 will be described with reference to FIGS.
As shown in FIG. 2, the EL display device 1 includes a substrate 20 having electrical insulation and pixel electrodes 23 connected to switching TFTs (not shown) arranged in a matrix on the substrate 20. A pixel electrode region (not shown), a power supply line 103 disposed around the pixel electrode region and connected to each pixel electrode 23, and a pixel portion 3 having a substantially rectangular shape in plan view located at least on the pixel electrode region ( 2 is an active matrix type that is configured to include a dash-dotted line frame in FIG.
In the present embodiment, the substrate 20 and the various circuits including the TFTs formed on the substrate 20, the interlayer insulating film, and the like are referred to as the base 200 (see FIGS. 3 and 4).

The pixel unit 3 includes an actual display area 4 in the center (within the two-dot chain line frame in FIG. 2) and a dummy area 5 (area between the one-dot chain line and the two-dot chain line) arranged around the actual display area 4. And it is divided into.
In the actual display area 4, display areas R, G, and B each having a pixel electrode 23 are arranged in a matrix so as to be separated from each other in the AB direction and the CD direction.
Further, scanning line driving circuits 80 are disposed on both sides of the actual display area 4 in FIG. These scanning line drive circuits 80 are arranged below the dummy region 5.

  Further, an inspection circuit 90 is arranged above the actual display area 4 in FIG. The inspection circuit 90 is a circuit for inspecting the operating state of the EL display device 1 and includes, for example, inspection information output means (not shown) for outputting the inspection result to the outside, and is displayed during manufacture or at the time of shipment. The apparatus is configured to be able to inspect the quality and defect of the apparatus. The inspection circuit 90 is also disposed below the dummy area 5.

  The scanning line driving circuit 80 and the inspection circuit 90 are configured such that the driving voltage is applied from a predetermined power supply unit via a driving voltage conducting unit (not shown) and a driving voltage conducting unit (not shown). Further, drive control signals to the scanning line drive circuit 80 and the inspection circuit 90 are supplied from a predetermined main driver or the like that controls the operation of the EL display device 1, and a drive control signal conduction unit (not shown) and a drive control signal conduction unit. (Not shown) and transmitted and applied. The drive control signal in this case is a command signal from a main driver or the like related to control when the scanning line drive circuit 80 and the inspection circuit 90 output signals.

In addition, as shown in FIGS. 3 and 4, the EL display device 1 includes a light emitting element (organic EL) including a pixel electrode 23, an organic partition layer (pixel partition) 221, an organic functional layer 110, and a cathode 50 on a substrate 200. A large number of elements) are formed, and further, the protective layer 52, the buffer layer 210, the gas barrier layer 30 and the like are formed by covering them.
The organic functional layer 110 is typically a light emitting layer 60 (electroluminescence layer), and a carrier injection layer such as a hole injection layer, a hole transport layer 70, an electron injection layer, an electron transport layer, or carrier transport. A layer is provided. Furthermore, a hole blocking layer (hole blocking layer) and an electron blocking layer (electron blocking layer) may be provided.

  In the case of a so-called top emission type, the substrate 20 constituting the base body 200 is configured to take out light emission from the gas barrier layer 30 side, which is the opposite side of the substrate 20, so that either a transparent substrate or an opaque substrate can be used. . Examples of opaque substrates include ceramics such as alumina, metal sheets such as stainless steel that have been subjected to insulation treatment such as surface oxidation, thermosetting resins and thermoplastic resins, and films thereof (plastic films). It is done.

  Further, in the case of a so-called bottom emission type, since light emission is extracted from the substrate 20 side, a transparent or semi-transparent substrate 20 is employed. For example, glass, quartz, resin (plastic, plastic film) and the like can be mentioned, and a glass substrate is particularly preferably used. In the present embodiment, a top emission type in which light emission is extracted from the gas barrier layer 30 side is used. Therefore, the above-described opaque substrate, for example, an opaque plastic film or the like is used as the substrate 20.

A circuit unit 11 including a driving TFT 123 for driving the pixel electrode 23 and the like is formed on the substrate 20, and a large number of light emitting elements (organic EL elements) are provided thereon. The light emitting element includes a pixel electrode 23 that functions as an anode, a hole transport layer 70 that injects / transports holes from the pixel electrode 23, a light emitting layer 60 that includes an organic EL material, and a cathode 50. It is constituted by that.
Based on such a configuration, the light emitting element emits light by combining holes injected from the hole transport layer 70 and electrons from the cathode 50 in the light emitting layer 60.

  Since the pixel electrode 23 is a top emission type in the present embodiment, it does not need to be transparent, and may have a multilayer structure such as a reflective layer / inorganic insulating layer / transparent anode in order to further improve reflectivity. The reflective layer is a layer that positively reflects the light emitted from the light emitting layer 60 to the cathode 50 side, and an aluminum alloy or the like is used. Through an inorganic insulating layer such as silicon nitride, a hole having a work function of 5 eV or more is injected. A highly conductive metal oxide conductive film such as ITO (Indium Tin Oxide) is used for the anode.

  As a material for forming the hole transport layer 70, for example, a polythiophene derivative, a polypyrrole derivative, or a doped body thereof is used. Specifically, 3,4-polyethylenedioxythiophene / polystyrene sulfonic acid (PEDOT / PSS) dispersion, that is, 3,4-polyethylenedioxythiophene is dispersed in polystyrene sulfonic acid as a dispersion medium. The hole transport layer 70 can be formed using a dispersion liquid in which is dispersed in water.

As a material for forming the light emitting layer 60, a known light emitting material capable of emitting fluorescence or phosphorescence can be used. Specifically, (poly) fluorene derivative (PF), (poly) paraphenylene vinylene derivative (PPV), polyphenylene derivative (PP), polyparaphenylene derivative (PPP), polyvinylcarbazole (PVK), polythiophene derivative, polymethyl Polysilanes such as phenylsilane (PMPS) are preferably used.
In addition, these polymer materials include polymer materials such as perylene dyes, coumarin dyes, rhodamine dyes, rubrene, perylene, 9,10-diphenylanthracene, tetraphenylbutadiene, Nile red, coumarin 6, and quinacridone. It can also be used by doping a low molecular weight material such as.
In addition, it replaces with the polymeric material mentioned above, a conventionally well-known low molecular material can also be used. In addition, an electron injection layer may be formed on the light emitting layer 60 as necessary.

Further, in this embodiment, the hole transport layer 70 and the light emitting layer 60 are the lyophilic control layer 25 (see FIG. 4) formed in a lattice shape on the substrate 200 as shown in FIGS. The hole transport layer 70 and the light emitting layer 60 which are surrounded by the organic partition layer (pixel partition) 221 and are surrounded by the organic partition layer 221 are element layers constituting a single light emitting element (organic EL element).
In addition, the angle with respect to the base | substrate 200 surface of each wall surface of the opening part 221a of the organic partition layer 221 is 110 degrees or more and 170 degrees or less. The reason for this angle is to facilitate the arrangement of the light emitting layer 60 in the opening 221a when the light emitting layer 60 is formed by a wet process.

As shown in FIGS. 2 to 4, the cathode 50 has a larger area than the total area of the actual display region 4 and the dummy region 5, and is formed so as to cover each, and the light emitting layer 60 and the organic partition layer 221. These are formed on the base body 200 in a state of covering the upper surface and the wall surface forming the outer portion of the organic partition wall layer 221. As shown in FIG. 3, the cathode 50 is connected to the cathode wiring 202 at a connection portion 50 b formed on the outer peripheral portion of the base body 200 outside the organic partition wall layer 221. The cathode wiring 202 is formed by a first cathode wiring 202a and a second cathode wiring 202b, and has a so-called double wiring structure. The cathode wiring 202 may be only one of the first cathode wiring 202a and the second cathode wiring 202b.
Specifically, in the connection portion 50b, the cathode 50 and the cathode wiring 202a are electrically connected through a contact hole 50a provided in the second interlayer insulating film 284. Further, the cathode wiring 202 is electrically connected to the flexible substrate 203, whereby the cathode 50 is connected to the driving IC 204 via the flexible substrate 203.

  As a material for forming the cathode 50, since this embodiment is a top emission type, it needs to be light transmissive, and therefore, a transparent conductive material is used. ITO is suitable as the transparent conductive material, but in addition to this, for example, indium oxide / zinc oxide based amorphous transparent conductive film (Indium Zin Oxide: IZO) is used. Can do. In the present embodiment, ITO is used.

  The cathode 50 is preferably made of a material having a large electron injection effect (a work function of 4 eV or less). For example, calcium, magnesium, sodium, lithium metal, or a metal compound thereof. Examples of the metal compound include metal fluorides such as calcium fluoride, metal oxides such as lithium oxide, and organometallic complexes such as acetylacetonato calcium. In addition, these materials alone have high electrical resistance and do not function as electrodes, so patterning a metal layer such as aluminum, gold, silver, or copper to avoid the light emitting region, or transparent metals such as ITO or tin oxide You may use it in combination with the laminated body with an oxide conductive layer. In the present embodiment, a laminate of lithium fluoride, magnesium-silver alloy, and ITO is used by adjusting the film thickness to obtain transparency. The film thickness of the cathode 50 is preferably about 10 nm to 200 nm.

As shown in FIGS. 3 and 4, a protective layer 52 is formed on the upper layer of the cathode 50 in a range wider than the organic partition wall layer 221 and covering the cathode 50. The protective layer 52 is provided to relieve the load applied on the cathode 50 when the buffer layer 210 described later is formed. It is provided to prevent damage to the cathode 50 during the manufacturing process due to residual moisture or the like in the buffer layer 210. Further, it is also provided for the purpose of flatness, defoaming property, adhesion, and lowering of the side edge when applying the buffer layer forming material.
The protective layer 52 is formed of a material such as a silicon compound containing nitrogen, such as silicon nitride or silicon nitride oxide, which is dense and has high elastic modulus in consideration of transparency, denseness, water resistance, insulation, and gas barrier properties. The ones made are preferred. As a method for forming the protective layer 52, a high-density plasma film forming method such as an ECR sputtering method or an ion plating method is used. Further, the thickness of the protective layer 52 is preferably about 50 nm to 400 nm.

  As shown in FIGS. 3 and 4, a buffer layer 210 is provided on the upper layer portion of the protective layer 52. The buffer layer 210 includes a buffer layer 210 a that covers the step generated by the organic partition layer 221 in the region where the cathode 50 is formed, and a step generated at the connection portion 50 b between the cathode 50 and the cathode wiring 202. And a buffer layer 210b covering the surface. Specifically, the buffer layer 210 a covers a convex step generated by the organic partition wall layer 221 provided on the substrate 200, and the buffer layer 210 b is a contact hole of the connection portion 50 b between the cathode 50 and the cathode wiring 202. Each is formed on the base body 200 so as to cover the concave step generated by 50a. The stepped surface is substantially flattened by the buffer layer 210, and the gas barrier layer 30 made of a hard film formed on the buffer layer 210 is also flattened, so that there is no portion where stress is concentrated. Generation of cracks can be prevented. The buffer layer 210 may be formed in common so as to continuously cover the step.

  The buffer layer 210 is preferably formed on the protective layer 52 using a screen printing method under a reduced pressure vacuum. The buffer layer forming material is transferred onto the substrate 200 (on the protective layer 52) by bringing a mask having a non-coated area formed of a resin cured material on the screen mesh into contact with the substrate 200 and pressing with a squeegee. Since application (transfer) is performed in a reduced-pressure atmosphere, bubbles generated on the application surface during transfer can be removed while maintaining an environment with low moisture.

  The buffer layer 210 is an organic compound material that is excellent in fluidity and free from solvents and volatile components, and is a raw material of a polymer skeleton, as a raw material main component before curing. An epoxy monomer / oligomer having an epoxy group and a molecular weight of 3000 or less is preferably used (monomer definition: molecular weight 1000 or less, oligomer definition: molecular weight 1000 to 3000). For example, bisphenol A type epoxy oligomer, bisphenol F type epoxy oligomer, phenol novolac type epoxy oligomer, polyethylene glycol diglycidyl ether, alkyl glycidyl ether, 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate, There are ε-caprolactone-modified 3,4-epoxycyclohexylmethyl 3 ′, 4′-epoxycyclohexanecarbochelate, and these are used singly or in combination.

Moreover, as the curing agent that reacts with the epoxy monomer / oligomer, one that forms a cured film with excellent electrical insulation and adhesiveness, high hardness, toughness, and excellent heat resistance, excellent transparency, and curing properties. An addition polymerization type with little variation is preferable. For example, 3-methyl-1,2,3,6-tetrahydrophthalic anhydride, methyl-3,6-endomethylene-1,2,3,6-tetrahydrophthalic anhydride, 1,2,4,5-benzene Acid anhydride curing agents such as tetracarboxylic dianhydride and 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride are preferred. Furthermore, it becomes easy to cure at low temperature by adding an alcohol having a large molecular weight and hardly volatilizing such as 1,6-hexanediol as a reaction accelerator for promoting the reaction (ring opening) of the acid anhydride. These curings are performed by heating in the range of 60 to 100 ° C., and the cured film becomes a polymer having an ester bond.
Further, by adding a relatively high molecular weight substance such as aromatic amines, alcohols, and aminophenols as a curing accelerator for promoting acid anhydride ring-opening, curing at a low temperature and in a short time becomes possible.
A cation-releasing photopolymerization initiator often used for shortening the curing time is not preferable because it causes coloring and rapid curing shrinkage, but a silane coupling agent that improves adhesion with the gas barrier layer 30, Water replenishers such as isocyanate compounds and additives such as fine particles that prevent shrinkage during curing may be mixed.

  The viscosity of each raw material is preferably 1000 mPa · s (room temperature: 25 ° C.) or more. This is because it penetrates into the light emitting layer 60 immediately after coating and does not generate a non-light emitting region called a dark spot. Further, the viscosity of the buffer layer forming material obtained by mixing these raw materials is preferably 500 mPa · s to 20000 mPa · s, particularly 2000 mPa · s to 10000 mPa · s (room temperature).

The film thickness of the buffer layer 210 is preferably 2 μm to 10 μm. If the thickness of the buffer layer 210 is 2 μm or more, it is thicker than the total thickness of the cathode 50 and the protective layer 52, so that the level difference caused by the protective layer 52 can be flattened, and foreign matter is mixed. This is because the occurrence of defects in the gas barrier layer 30 can be prevented.
Moreover, as a characteristic after hardening, it is preferable that the elastic modulus of the buffer layer 210 is 1 GPa to 10 GPa. If it is 10 GPa or more, the stress at the time of planarizing the organic partition wall layer 221 cannot be absorbed, and if it is 1 GPa or less, wear resistance, heat resistance and the like are insufficient.

Further, as shown in FIGS. 2 to 4, an organic barrier rib that covers the light-emitting layer 60, the organic barrier rib layer 221, and the cathode 50 and is relatively poor in water resistance among the sealing layers, as shown in FIGS. The gas barrier layer 30 is formed in a wide range covering up to the end portions of the layer 221 and the protective layer 52 or in the same range as the protective layer 52.
The gas barrier layer 30 is for preventing oxygen and moisture from entering, and thereby, deterioration of the cathode 50 and the light emitting layer 60 due to oxygen and moisture can be suppressed. In consideration of transparency, gas barrier properties, and water resistance, the gas barrier layer 30 is preferably formed of a silicon compound containing nitrogen, that is, silicon nitride or silicon oxynitride.
As a film formation method of the gas barrier layer 30, it is necessary to form a dense and defect-free film in order to shut off a gas such as water vapor. Preferably, a high-density plasma film formation method capable of forming a dense film at a low temperature is used. Form.
The gas barrier layer 30 may be formed of a material having the same elastic modulus as that of the protective layer 52. The film thickness of the gas barrier layer 30 is preferably about 200 nm to 600 nm. This is because if it is less than 200 nm, the coverage with respect to the foreign matter is insufficient and a through hole is partially formed, and the gas barrier property may be impaired. If it exceeds 600 nm, cracking due to stress occurs. Because there is a fear.

Furthermore, the gas barrier layer 30 may have a laminated structure, or may have a configuration in which the composition is not uniform, and the oxygen concentration particularly changes continuously or discontinuously.
In addition, since the top emission type is used in the present embodiment, the gas barrier layer 30 needs to have translucency. Therefore, by adjusting the material and film thickness appropriately, the light beam in the visible light region can be obtained in the present embodiment. The transmittance is set to 80% or more, for example.

Here, the structure of the end of the buffer layer 210 will be described with reference to FIG. FIG. 5 is an enlarged view showing an end portion of the buffer layer. In particular, the contact angle with the protective layer 52 will be described.
The buffer layer 210 is formed on the protective layer 52 and is in contact with the surface of the protective layer 52 at the contact angle α at the end thereof. Here, the contact angle α is 45 ° or less, and more preferably about 1 ° to 20 ° or less.
As a result, the gas barrier layer 30 formed in the upper layer of the buffer layer 210 does not have a sharp shape change at the end portion, and the shape changes gently, so that cracks or the like due to stress concentration at the end portion of the buffer layer 210 may occur. Generation of defects is prevented. Therefore, it becomes possible to maintain the sealing ability over a long period of time.

Returning to FIG. 3 and FIG. 4, an adhesive layer 205 and a surface protection substrate 206 are provided in the upper layer portion of the gas barrier layer 30.
The adhesive layer 205 fixes the surface protective substrate 206 on the gas barrier layer 30 and has a buffer function against mechanical shock from the outside, and protects the organic functional layer 110 and the gas barrier layer 30. The adhesive layer 205 is formed of an adhesive made of a material that is softer than the surface protective substrate 206 and has a lower glass transition point, for example, a resin such as urethane, acrylic, epoxy, or polyolefin. A transparent resin material is preferred. Further, it may be formed of a two-component mixed material in which a curing agent is added for curing at a low temperature.
In addition, it is preferable to add a silane coupling agent or alkoxysilane to such an adhesive layer 205, so that the adhesion between the formed adhesive layer 205 and the gas barrier layer 30 is better. Therefore, the buffer function against mechanical shock is increased.
In particular, when the gas barrier layer 30 is formed of a silicon compound, the adhesion to the gas barrier layer 30 can be improved by a silane coupling agent or alkoxysilane, and thus the gas barrier property of the gas barrier layer 30 is improved. be able to.

The surface protection substrate 206 is a layer provided on the adhesive layer 205 and having at least one of functions such as pressure resistance, wear resistance, external light antireflection, gas barrier properties, and ultraviolet blocking properties.
As the material of the surface protection substrate 206, glass, a DLC (Diamond Like Carbon) layer, a transparent plastic, or a transparent plastic film is employed. Here, as the plastic material, for example, PET, acrylic, polycarbonate, polyolefin and the like are employed.
Further, the surface protective substrate 206 may be provided with an optical structure such as an ultraviolet blocking / absorbing layer, a light reflection preventing layer, a heat radiating layer, a lens, a color wavelength conversion layer, and a mirror. In addition, a color filter function may be provided.
Since the EL display device 1 is a top emission type, both the surface protection substrate 206 and the adhesive layer 205 need to be light-transmitting, but this is not necessary in the case of the bottom emission type.

Next, an example of a method for manufacturing the EL display device 1 according to this embodiment will be described with reference to FIGS. Each cross-sectional view shown in FIGS. 6 and 7 corresponds to the cross-sectional view taken along the line AB in FIG.
In the present embodiment, the EL display device 1 as a light emitting device is a top emission type, and a known technique is used for the step of forming the circuit portion 11 on the surface of the substrate 20. Since it can, explanation is omitted.

First, as shown in FIG. 6A, a conductive film to be the pixel electrode 23 is formed so as to cover the entire surface of the substrate 20 on which the circuit portion 11 is formed, and this transparent conductive film is further patterned. As a result, the pixel electrode 23 electrically connected to the drain electrode 244 through the contact hole 23a of the second interlayer insulating film 284 is formed, and at the same time, the dummy pattern 26 in the dummy region is also formed.
3 and 4, the pixel electrode 23 and the dummy pattern 26 are collectively referred to as the pixel electrode 23. The dummy pattern 26 is configured not to be connected to the lower metal wiring via the second interlayer insulating film 284. That is, the dummy pattern 26 is arranged in an island shape and has substantially the same shape as the shape of the pixel electrode 23 formed in the actual display region 4. Of course, a structure different from the shape of the pixel electrode 23 formed in the actual display region 4 may be used.

  Next, as shown in FIG. 6B, a lyophilic control layer 25 that is an insulating layer is formed on the pixel electrode 23, the dummy pattern 26, and the second interlayer insulating film 284. In the pixel electrode 23, the lyophilic control layer 25 is formed in such a manner that a part of the pixel electrode 23 is opened, and hole movement from the pixel electrode 23 is enabled in the opening 25a (see FIG. 3). On the contrary, in the dummy pattern 26 in which the opening 25a is not provided, the insulating layer (lyophilic control layer) 25 serves as a hole movement shielding layer and does not cause hole movement. Subsequently, in the lyophilic control layer 25, a BM (black matrix) (not shown) is formed in a concave portion formed between two different pixel electrodes 23. Specifically, the concave portion of the lyophilic control layer 25 is formed by sputtering using metallic chromium.

Then, as shown in FIG. 6C, an organic partition layer 221 is formed so as to cover a predetermined position of the lyophilic control layer 25, specifically, the BM described above.
As a specific method for forming the organic barrier layer 221, for example, an organic resin layer obtained by applying a resist such as an acrylic or imide material dissolved in a solvent by various coating methods such as a spin coating method or a dip coating method. Form. The constituent material of the organic resin layer may be any material as long as it does not dissolve in the ink solvent described later and can be easily patterned by etching or the like.

  Furthermore, the organic resin layer is patterned using a photolithography technique and an etching technique, and an opening 221a is formed in the organic resin layer, thereby forming an organic partition layer 221 having a wall surface in the opening 221a. Here, the wall surface forming the opening 221a is formed so that the angle with respect to the surface of the base body 200 is 110 degrees or more and 170 degrees or less.

  Next, a region showing lyophilicity and a region showing liquid repellency are formed on the surface of the organic partition layer 221. In the present embodiment, each region is formed by plasma processing. Specifically, in the plasma treatment, the upper surface of the organic partition wall layer 221, the wall surface of the opening 221a, the electrode surface 23c of the pixel electrode 23, and the upper surface of the lyophilic control layer 25 are made lyophilic. The ink making step includes an ink repellent step, an ink repellent step for making the upper surface of the organic partition layer 221 and the wall surface of the opening 221a liquid repellent, and a cooling step.

  Next, the hole transport layer 70 is formed by a hole transport layer forming step. In this hole transport layer forming step, for example, a hole transport layer material is applied onto the electrode surface 23c by a droplet discharge method such as an ink jet method or a spin coating method, and then a drying process and a heat treatment are performed. A hole transport layer 70 is formed on 23.

  Next, the light emitting layer 60 is formed by the light emitting layer forming step. In this light emitting layer forming step, the light emitting layer forming material is discharged onto the hole transport layer 70 by, for example, an ink jet method, and then dried and heat-treated to thereby form the inside of the opening 221a formed in the organic partition wall layer 221. The light emitting layer 60 is formed. In this light emitting layer forming step, a nonpolar solvent that is insoluble in the hole transporting layer 70 is used as a solvent used for the light emitting layer forming material in order to prevent re-dissolution of the hole transporting layer 70.

  Next, as shown in FIG. 6D, the cathode 50 is formed by the cathode layer forming step. In this cathode layer forming step, for example, a magnesium-silver co-deposited layer by an evaporation method and an ITO film formed by a physical vapor deposition method such as an ion plating method are used as the cathode 50. At this time, the cathode 50 is formed so as to cover not only the upper surfaces of the light emitting layer 60 and the organic barrier layer 221 but also the wall surface forming the outer portion of the organic barrier layer 221.

Next, as shown in FIG. 7A, a protective layer 52 is formed on the cathode 50.
For example, an inorganic compound such as a silicon compound containing nitrogen such as silicon oxide is formed to a thickness of about 50 nm to 400 nm by a high density plasma film formation method such as an ECR sputtering method or an ion plating method.

  Next, as shown in FIG. 7B, the buffer layer 210 is applied on the protective layer 52 by screen printing. At this time, it is applied in a reduced pressure atmosphere in the range of 100 Pa to 10000 Pa so as not to cause film defects caused by bubbles.

  The screen printing method is a method that can be applied in a reduced-pressure atmosphere, and therefore is good at using a relatively medium to high viscosity coating solution. In particular, the screen printing method has an advantage that the coating control is simple by the pressure movement of the squeegee, and the film thickness uniformity and the patterning property are excellent by using the screen mesh.

As shown in FIG. 7C, the gas barrier layer 30 is formed so as to cover the buffer layer 210. The gas barrier layer 30 is preferably a transparent thin film mainly made of silicon nitride or silicon oxynitride, which is formed by a high-density plasma film formation method or the like under reduced pressure. Further, it has a denseness to completely block small molecule water vapor, and preferably has a slight compressive stress. The film density is preferably 2.3 / cm ³ or more, and the film thickness is preferably 200 nm to 600 nm.

As a specific method for forming the gas barrier layer 30, first, a film is formed by a physical vapor deposition method such as a sputtering method or an ion plating method, and then a chemical vapor deposition method such as a plasma CVD method is used. A membrane may be performed. Physical vapor deposition methods such as sputtering and ion plating generally provide a dense film with relatively good adhesion to a heterogeneous substrate surface without using harmful source gases. In the phase growth method, a film having a high film forming speed, a low stress, a small number of defects excellent in step coverage, and a dense and good film quality can be obtained. These methods can be selected in a timely manner in consideration of mass productivity.
Further, the gas barrier layer 30 may be formed as a single layer with the same material as described above, or may be formed by laminating a plurality of layers with different materials. Although formed, the composition may be changed continuously or discontinuously in the film thickness direction.

Next, an adhesive layer 205 and a surface protective substrate 206 are provided on the gas barrier layer 30 (see FIGS. 3 and 4). The adhesive layer 205 is applied substantially uniformly on the gas barrier layer 30 by a screen printing method, a slit coating method, or the like, and the surface protection substrate 206 is bonded thereon.
Since the surface protective substrate 206 has functions such as pressure resistance, abrasion resistance, light reflection prevention, gas barrier properties, and ultraviolet blocking properties, the organic functional layer 110, the cathode 50, and the gas barrier layer 30 also have this surface. It can be protected by the protective substrate 206, and thus the lifetime of the light emitting element can be extended.
In addition, since the adhesive layer 205 exhibits a buffering function against mechanical impact, when mechanical impact is applied from the outside, the mechanical impact on the gas barrier layer 30 and the light emitting element inside the gas barrier layer 30 is alleviated. It is possible to prevent functional deterioration of the light-emitting element due to mechanical impact.
As described above, the EL display device 1 is formed.

[Second Embodiment]
Hereinafter, the EL display devices 2 and 3 according to the second embodiment of the present invention will be described. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
FIG. 8A is a schematic plan view in which the EL display devices 2 and 3 are formed so as to be adjacent to each other. FIG. 8B is a schematic cross-sectional view taken along the line EF showing a boundary portion between the EL display device 2 and the EL display device 3 in FIG.

  As shown in FIG. 8B, the EL display devices 2 and 3 are formed on the common substrate 21 so as to be adjacent to each other, and the protective layer 52, the buffer layer 210, and the gas barrier layer 30 include the EL display device 2. And 3 are formed in common. That is, the buffer layer 210 b that covers the concave step generated at the connection portion between the cathode 50 and the cathode wiring 202 is formed across the EL display devices 2 and 3.

  Further, the protective layer 52 below the buffer layer 210 and the gas barrier layer 30 above the buffer layer 210 are also formed across adjacent EL display devices in the same manner as the buffer layer 210b. By forming the buffer layer 210b across the step portions of the adjacent EL display devices, the pattern accuracy of the buffer layer 210b can be relaxed. The configuration and materials similar to those of the first embodiment are adopted except that the buffer layer 210b, the protective layer 52, and the gas barrier layer are formed across adjacent EL display devices. As a result, it is possible to obtain an EL display device that prevents defects due to the formation of the buffer layer 210 and prevents the light emission characteristics and the light emission lifetime from being lowered.

  Further, in the first and second embodiments of the EL display device described above, the buffer layer 210 includes a buffer layer 210 a that covers a convex step generated by the organic partition layer 221 provided on the base 200, a cathode 50, and the like. Although the buffer layer 201b that covers the concave step generated in the second interlayer insulating film 284 at the connection portion 50b with the cathode wiring 202 has been described, the present invention is not limited to this. As shown in FIG. 9, when wiring such as the power supply line 103, the drive voltage conducting unit 310, and the drive control signal conducting unit 320 is provided on the outer periphery of the base body 200 outside the organic partition layer 221, Then, the convex step generated in the second interlayer insulating film 284 may be formed so as to cover the buffer layer 210c. In this way, since the buffer layer 210c covers the convex step caused by the wiring, the gas barrier layer 30 made of a hard film formed on the buffer layer 210 with the step surface substantially flattened by the buffer layer 210 is formed. Since the planarization is performed, there is no portion where stress is concentrated, thereby preventing generation of cracks in the gas barrier layer 30.

  In the above-described embodiment of the EL display device, the top emission type has been described as an example. However, the present invention is not limited to this, and the bottom emission type or a type of emitting emitted light on both sides is also described. It can also be applied to things.

In the case of a bottom emission type or a type that emits light to both sides, the switching TFT 112 and the driving TFT 123 formed on the substrate 200 are not formed directly below the light emitting element but directly below the organic partition layer 221. However, it is preferable to increase the aperture ratio.
In the embodiment, the first electrode functions as the anode 23 and the second electrode functions as the cathode 50. However, these are reversed so that the first electrode functions as the cathode and the second electrode functions as the anode. You may comprise. However, in that case, the formation positions of the light emitting layer 60 and the hole transport layer 70 need to be interchanged.

Next, the electronic apparatus of this embodiment will be described with reference to FIG.
The electronic device has the EL display device 1 described above as a display unit, and specifically, the one shown in FIG.
FIG. 10A is a perspective view showing an example of a mobile phone. In FIG. 10A, a cellular phone 1000 includes a display unit 1001 using the EL display device 1 described above.
FIG. 10B is a perspective view illustrating an example of a wristwatch type electronic device. In FIG. 10B, a timepiece (electronic device) 1100 includes a display unit 1101 using the EL display device 1 described above.
FIG. 10C is a perspective view showing an example of a portable information processing apparatus such as a word processor or a personal computer. In FIG. 10C, the information processing apparatus 1200 includes an input unit 1200 such as a keyboard, a display unit 1206 using the EL display device 1 described above, and an information processing apparatus body (housing) 1204.
FIG. 10D is a perspective view showing an example of a thin large-screen television. 10D, a thin large-screen television 1300 includes a thin large-screen television main body (housing) 1302, an audio output unit 1304 such as a speaker, and a display unit 1306 using the EL display device 1 described above.

Each of the electronic devices shown in FIGS. 10A to 10D includes the display units 1001, 1101, 1206, and 1306 having the EL display device 1 described above, so that the life of the display unit can be extended. It will be.
In addition, the thin large-screen television 1300 shown in FIG. 10D applies the present invention that can seal the display portion regardless of the area, so that the display has a larger area (for example, a diagonal of 20 inches or more) than the conventional display. The unit 1306 is provided.

  Moreover, not only the case where the EL display device 1 is provided as a display unit but also an electronic device provided as a light emitting unit. For example, a page printer (image forming apparatus) provided with the EL display device 1 as an exposure head (line head) or a lighting device provided with the EL display device 1 as a light emitting unit may be used.

  DESCRIPTION OF SYMBOLS 1 ... EL display apparatus (light-emitting device) 23 ... Pixel electrode (1st electrode), 30 ... Gas barrier layer, 50 ... Cathode (second electrode), 52 ... Protective layer, 60 ... Light emitting layer, 110 ... Organic functional layer, DESCRIPTION OF SYMBOLS 200 ... Base | substrate, 210 ... Buffer layer, 221 ... Organic partition layer (partition), 221a ... Opening, 1000 ... Cell-phone (electronic device), 1100 ... Clock (electronic device), 1200 ... Information processing apparatus (electronic device), 1300: Thin large-screen television (electronic device), 1001, 1101, 1206, 1306 ... Display unit (light emitting device).

Claims (10)

On the first substrate ,
A first wiring;
A first electrode;
A partition having an opening corresponding to the first electrode;
An organic functional layer provided on the first electrode;
A second electrode provided on the partition and the organic functional layer;
A connection part for electrically connecting the second electrode and the first wiring;
A buffer layer provided on the second electrode;
A gas barrier layer provided on the buffer layer,
The second electrode has a first region that covers the partition and the organic functional layer , and a second region that is provided in the connection portion,
The buffer layer includes a first buffer layer that covers the first region, and a second buffer layer that covers the second region,
The electro-optical device, wherein the first buffer layer and the second buffer layer are not in contact with each other. A second wiring is provided on the first substrate ,
In plan view, a third buffer layer is provided on the second wiring,
The electro-optical device according to claim 1, wherein the first buffer layer, the second buffer layer, and the third buffer layer are not in contact with each other.   The electro-optical device according to claim 1, wherein the second wiring is a wiring for driving and controlling a light emitting element having the first electrode, the organic functional layer, and the cathode. The electro-optical device according to any one of claims 1 to 3, wherein the buffer layer is made of an organic material, and the gas barrier layer is made of an insulating inorganic compound.
Place.   The electro-optical device according to claim 1, further comprising a protective layer that covers the second electrode between the second electrode and the gas barrier layer.   The electro-optical device according to claim 5, wherein the protective layer is made of an insulating inorganic compound.   7. The electro-optical device according to claim 5, wherein a thickness of the buffer layer is larger than a total thickness of a thickness of the second electrode and a thickness of the protective layer. On the first substrate, a first wiring, a first electrode, a partition having an opening corresponding to the first electrode, an organic functional layer provided on the first electrode, the partition and the organic A second electrode provided on the functional layer, and a method of manufacturing an electro-optical device,
Forming a connection portion for electrically connecting the second electrode and the first wiring;
Forming a buffer layer provided on the second electrode;
Forming a gas barrier layer provided on the buffer layer,
The second electrode has a first region that covers the partition and the organic functional layer , and a second region that is provided in the connection portion,
The buffer layer includes a first buffer layer that covers the first region, and a second buffer layer that covers the second region,
The step of forming the buffer layer is performed so that the first buffer layer and the second buffer layer do not contact each other. A plurality of the electro-optical devices are formed on the first substrate,
In the step of forming the buffer layer, the second buffer layer is formed in common across the connection portions of the adjacent electro-optical devices on the first substrate.
The method of manufacturing an electro-optical device according to claim 8.   An electronic apparatus comprising the electro-optical device according to any one of claims 1 to 7.

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