JP2011171187A - Organic el display device and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To cure a photocuring resin formed between a sealing substrate and an organic EL element by ultraviolet ray with no damage on the organic EL element when manufacturing an organic EL display device. <P>SOLUTION: The organic EL display device includes a first substrate containing a lamination surface in which there are stacked a thin film transistor, a plurality of first electrodes formed on the thin film transistor to correspond to pixels, a plurality of barrier walls for dividing the first electrode for each pixel, an organic light emitting layer formed on the first electrode, and a second electrode formed on the organic light emitting layer. It also includes a transparent second substrate in which such ultraviolet ray absorbing film is formed to allow emission from the organic light emitting layer to penetrate but absorb ultraviolet ray on a counter surface opposed to the lamination surface of the first substrate, and a photocuring sealing material which glues the first substrate to the second substrate. The ultraviolet ray absorbing film formed on the counter surface of the second substrate is so provided as to correspond to each pixel divided by the barrier wall of the first substrate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to an organic EL display device formed by bonding a sealing substrate and an organic EL element substrate, and a method for manufacturing the organic EL display device.
About.

An organic EL (Electro Luminescence) display device has recently been applied to displays due to its thinness, space saving, light weight, and high luminance emission even at an applied voltage of about 10V. Is expected.
An organic EL element used in an organic EL display device has a configuration in which an organic layer capable of emitting light is sandwiched between electrodes. The organic layer is basically a laminate of a hole transport layer, a light emitting layer, and an electron transport layer. The electrode uses a transparent electrode as a cathode on the side from which light is extracted, and a reflective metal electrode as an anode on the opposite side. In such a configuration, by flowing current from both electrodes, electrons are injected from the electron transport layer, holes are injected from the hole transport layer to the light emitting layer, and the electrons and holes are recombined in the light emitting layer to emit light. .

  In the active matrix method, an organic layer is formed on a substrate (hereinafter referred to as “TFT substrate”) provided with a thin film transistor (hereinafter referred to as “TFT”), and light emitted from the light emitting layer is sandwiched between the TFTs. With this structure, the light can be extracted regardless of the wiring on the TFT substrate, thereby increasing the aperture ratio. It becomes possible.

  Note that an organic EL display device that displays a color image has a structure in which organic EL elements of three primary colors (RGB) are arranged in order on a substrate, and each organic EL element is a sub-pixel. In addition, as a method of forming an RGB organic EL element on a substrate in an active matrix top emission structure, for example, a method in which light emitting materials of three primary colors are separately applied, a method in which white light emission is divided into three primary colors by a color filter, In addition, there is a method of providing a color filter on a light emitting material of three primary colors.

Further, when the organic EL element is viewed from the display direction (viewing side), external light may be reflected by the reflective metal electrode and the contrast may be lowered. For this reason, it is necessary to suppress reflection of external light by arranging a circularly polarizing plate or a color filter on the front surface of the panel and by optimizing the structure of the organic EL element to cause interference of external light within the layer.
However, when a color filter is used, the cost increases due to the complexity of the manufacturing process, and thus a structure that does not use the color filter is desired.

  By the way, it is known that the organic layer in the organic EL element is deteriorated by oxygen or moisture in the air. Therefore, in order to prevent the intrusion of oxygen and moisture, for example, a transparent sealing substrate such as glass is generally bonded and sealed with a substrate on which an organic EL element is formed via an adhesive layer to form an airtight structure. Is. Examples of the adhesive layer include a thermosetting resin or an ultraviolet curable resin. When a thermosetting resin is used, outgas is generated during thermosetting, and the light emitting area of the organic EL element is reduced due to the influence. Phenomenon (shrink) may occur.

  Further, when an ultraviolet curable resin is used, outgassing is reduced by curing in a shorter time than a thermosetting resin by irradiating and curing ultraviolet rays from the sealing substrate side. However, when the ultraviolet rays reach the organic EL element, the organic layer may be deteriorated, and the organic EL element characteristics may be deteriorated due to chemical deterioration or heat generation of the light extraction electrode portion.

  Therefore, in order to prevent the deterioration of the organic EL element due to ultraviolet rays at the time of sealing as described above, in Patent Document 1, an ultraviolet blocking film that is a metal film is formed on a sealing substrate, and the surface on which the ultraviolet blocking film is formed is formed. When facing the organic EL element, the ultraviolet blocking film is disposed at a position corresponding to the organic layer to prevent the deterioration of the organic EL element, and is disposed in a region other than the region where the ultraviolet blocking film is formed. A technique for curing an ultraviolet curable sealant has been proposed.

JP 2003-332046 A

  However, the method of forming an ultraviolet blocking film, which is a metal film, on the sealing substrate can be applied to a structure (bottom emission structure) in which light emitted from the light emitting layer is extracted from the TFT substrate side, but a top emission structure. In this case, since the ultraviolet blocking film on the sealing substrate blocks light emission from the light emitting layer, light cannot be extracted. Moreover, even if the irradiated ultraviolet rays are not directly irradiated on the organic layer, the organic EL element characteristics may be deteriorated by repeatedly reflecting and scattering within the organic EL element and reaching the organic layer.

  The present invention has been made to solve the above-described problem, and a photocurable resin formed between a sealing substrate and an organic EL element can be cured by ultraviolet rays without damaging the organic EL element. An object of the present invention is to provide an organic EL display device and a method for manufacturing the organic EL display device.

In order to solve the above problems, an organic EL display device according to one embodiment of the present invention includes:
A thin film transistor, a plurality of first electrodes formed on the thin film transistor corresponding to a pixel, a plurality of partitions partitioning the first electrode for each pixel, and an organic light emitting layer formed on the first electrode A first substrate having a laminated surface on which the second electrode formed on the organic light emitting layer is laminated, and transmitting light emitted from the organic light emitting layer to a facing surface facing the laminated surface of the first substrate, A transparent second substrate on which an ultraviolet absorbing film that absorbs ultraviolet rays is formed, and a photocurable sealing material that bonds the first substrate and the second substrate, and facing the second substrate The ultraviolet absorbing film formed on the surface is provided at a position corresponding to each pixel defined by the partition of the first substrate.

In addition, an organic EL display device according to one embodiment of the present invention includes:
The ultraviolet absorbing film has a region where the light transmittance is 80% or more in a wavelength region of 380 nm or more and 780 nm or less, and has a region where the light transmittance is 10% or less in a wavelength region of 200 nm or more and less than 380 nm. It is an ultraviolet absorbing film having visible light permeability.

In addition, an organic EL display device according to one embodiment of the present invention includes:
The distance from the surface of the sealing substrate on the first substrate side to the first electrode on the first substrate is 100 μm or less.
In addition, an organic EL display device according to one embodiment of the present invention includes:
The partition is made of an ultraviolet absorbing material.

In addition, an organic EL display device according to one embodiment of the present invention includes:
The partition wall is formed by dispersing an ultraviolet absorber in a photocurable resin, and has a region where the light transmittance is 10% or less in a wavelength region of 200 nm or more and less than 380 nm.
In addition, a method for manufacturing an organic EL display device according to one embodiment of the present invention includes:
Forming a first step of forming a thin film transistor on the first substrate; a second step of forming a plurality of first electrodes corresponding to the pixels on the thin film transistor; and forming a plurality of partitions partitioning the first electrode for each pixel. A third step, a fourth step of forming an organic light emitting layer on the first electrode, a fifth step of forming a second electrode on the organic light emitting layer, and the second electrode of the first substrate. A second substrate having an ultraviolet absorbing film on a surface facing the formed surface, wherein the ultraviolet absorbing film is positioned corresponding to each pixel defined by the partition of the first substrate; And a sixth step of fixing the first substrate and the second substrate with a photocurable sealing material.

  According to the first aspect of the present invention, ultraviolet rays are irradiated through the second substrate by providing the ultraviolet absorbing film in the region facing the display pixel of the organic EL element on the surface of the second substrate facing the organic EL element. When the photocurable resin is cured, it is possible to cure the photocurable resin under the other regions without irradiating the display pixels directly under the ultraviolet absorbing film with ultraviolet rays. Note that in the case of a photo-setting resin combined with heat, a polymerization reaction spreads in the display pixel region through a subsequent heating step, and the entire panel can be cured.

  According to the second aspect of the present invention, the ultraviolet ray absorbing film has a light transmittance of 80% or more, preferably 90% or more in the visible light region of 380 nm or more and 780 nm or less. It becomes possible to take out from the substrate side, and in the wavelength region of 200 nm or more and less than 380 nm, the light transmittance can be suppressed to 10% or less, preferably 5% or less, so that damage to the organic EL layer due to ultraviolet rays can be suppressed. Become.

According to the third aspect of the present invention, the distance between the first substrate and the second substrate is set to 100 μm or less, preferably 10 μm or less, so that the ultraviolet light that has entered the photocurable resin portion from a region other than the ultraviolet absorbing film. However, it is possible to suppress the spread to the display pixel region before reaching the first substrate, and it is possible to suppress damage to the organic EL layer due to ultraviolet rays.
According to the invention described in claim 4, by providing the partition wall having ultraviolet absorptivity between the display pixels adjacent to each other on the first substrate, when the ultraviolet rays reach the first substrate, they are absorbed by the partition wall and reflected. It becomes possible to suppress scattering.

According to the invention described in claim 5, fine patterning and absorption of ultraviolet rays are possible by forming the partition walls using a material in which an ultraviolet absorbent is dispersed in a photocurable resin. In addition, when the light transmittance is 10% or less, preferably 5% or less in a wavelength region of 200 nm or more and less than 380 nm, it is possible to suppress reflection and scattering of ultraviolet rays irradiated to the partition wall.
According to the manufacturing method of claim 6, the light-curing resin is bonded to the position of the display pixel of the first substrate through the photo-curing resin so that the UV-absorbing film of the second substrate is opposed to the photo-curing resin. By curing the photocurable resin, the photocurable resin can be cured without deteriorating the organic EL characteristics of the display pixels.

Schematic which shows the cross-section of the organic electroluminescence display 1 which concerns on 1st Embodiment. The figure which showed the pattern example of the ultraviolet absorption film 11 compared with the pattern of the partition 17 formed on the organic EL element substrate 40. (A) is the figure which showed typically the effect | action at the time of using the partition 27 which does not have an ultraviolet absorptivity. (B) is the figure which showed typically the effect | action at the time of using the organic EL apparatus 1 which concerns on 1st Embodiment. (A) In the organic EL display device 1, the distance between the surface of the sealing substrate 12 on the organic EL element substrate 40 side after fixing and the surface of the transparent electrode 14 on the organic EL element substrate 40 is made larger than 100 μm. The figure which showed the effect | action in the case typically. (B) In the organic EL display device 1, the distance between the surface of the sealing substrate 12 on the organic EL element substrate 40 side after fixing and the surface of the transparent electrode 14 on the organic EL element substrate 40 is set to 100 μm or less. The figure which showed the effect | action in the case typically.

Embodiments of an organic EL display device and a method for manufacturing the organic EL display device according to the present invention will be described below with reference to the drawings.
(First embodiment)
(Constitution)
FIG. 1 is a schematic diagram showing a cross-sectional structure of an organic EL display device 1 according to the first embodiment.
In FIG. 1, the organic EL display device 1 includes an organic EL element substrate 40, a photocurable resin 13, and a sealing substrate 12.

(Configuration of organic EL element substrate 40)
The organic EL element substrate 40 includes a glass substrate 25, a TFT 30, a display pixel unit 18, and a partition wall 17.
As a material of the glass substrate 25, plastic film or sheet such as glass, quartz, polypropylene, polyethersulfone, polycarbonate, cycloolefin polymer, polyarylate, polyamide, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, etc. should be used. However, it is not limited to these.

A plurality of TFTs 30 are provided for each display pixel unit 18 on the glass substrate 25. The TFT 30 includes an interlayer insulating film 19, a drain electrode 20, a source electrode 21, a semiconductor film 22, a gate insulating film 23, and a gate electrode 24. The structure of the TFT 30 is not limited to this as long as it can control the driving of the display pixel unit 18.
The display pixel unit 18 includes a reflective electrode 16, an organic layer 15, and a transparent electrode 14. The display pixel unit 18 is an organic EL element, and is formed in a layer (viewing side) above the layer on which the TFT 30 is formed.

  The reflective electrode 16 is formed on the TFT 30 and functions as an anode of the display pixel unit 18. As the reflective electrode 16, it is preferable to use a metal having excellent reflectance such as aluminum or silver. By forming a transparent conductive film such as ITO (Indium Tin Oxide) on the reflective electrode 16, it is possible to reduce the energy barrier between the reflective electrode 16 and the organic layer 15 and improve the carrier injection property. It becomes.

The organic layer 15 is formed on the reflective electrode 16 and is configured by laminating a hole transport layer, a light emitting layer, and an electron transport layer. The light emitting layer emits light by recombination of holes supplied from the reflective electrode 16 and electrons supplied from the transparent electrode 14. Examples of the organic light-emitting material for the organic layer 15 include coumarin, perylene, pyran, anthrone, porphyrene, quinacridone, N, N′-dialkyl substituted quinacridone, naphthalimide, N, N′-diaryl substitution. There are pyrrolopyrrole, iridium complex, and other luminescent dyes dispersed in polymers such as polystyrene, polymethylmethacrylate, polyvinylcarbazole, and polyarylene, polyarylene vinylene, and polyfluorene polymer materials. For example, but not limited to.
The organic layer 15 can also have a multilayer structure. Further, when the material is a polymer material, the organic layer 15 can be formed by a solution coating method such as an ink jet method or a printing method.

  The transparent electrode 14 is formed on the organic layer 15 and functions as a cathode of the display pixel unit 18. As a material for the transparent electrode 14, it is desirable to use a substance having a low work function so that the electron injection efficiency into the organic layer 15 is high. The transparent electrode 14 can have a multilayer structure using different materials, and preferably a layer (electron injection layer) made of a material capable of improving the electron injection property and the in-plane conductivity. For example, a laminated structure of layers (in-plane conductive layers) made of the material to be formed can be used.

The material used for the electron injection layer is preferably a metal thin film having a low work function so that electrons can be efficiently injected. For example, an electron injection layer can be formed by forming an alloy of aluminum and lithium having a low work function or an alloy of magnesium and silver as thin as about 10 nm.
Examples of the material used for the in-plane conductive layer include an oxide transparent conductive film, or a metal thin film formed thin enough to transmit visible light.

The material of the transparent conductive film is preferably an oxide transparent conductive film containing one kind or two or more kinds of indium oxide, tin oxide, and zinc oxide, and the film thickness is sufficient in-plane conductivity. Thus, it is preferable that it is about 100 nm, for example.
As the metal thin film, a metal having high conductivity such as aluminum or silver can be used. The film thickness is preferably about 10 nm so as to satisfy the in-plane conductivity and the visible light transmittance.

A film made of SiNX, SiOX, or the like can be formed on the transparent electrode 14, and a passivation film that protects the organic EL element substrate 40 from oxygen, moisture, or the like can be formed.
The partition wall 17 is formed between the adjacent display pixel portions 18. As a material for the partition wall 17, a material having ultraviolet absorptivity is preferable. For example, a material obtained by dispersing a UV absorber in the photocurable resin 13 is used. Examples of the ultraviolet absorber include benzotriazole, benzophenone, salicylate compounds, and the like.
Further, when the material of the organic layer 15 is a polymer material and the partition wall 17 is formed by a solution coating method such as an inkjet method or a printing method, the partition wall 17 prevents the solution from flowing out to the adjacent display pixel portion 18 at the time of coating. Can play the role of a bank.

(Configuration of the photocurable resin 13)
The photocurable resin 13 is filled in the internal space between the sealing substrate 12 and the organic EL element substrate 40, and the sealing substrate 12 and the organic EL element substrate 40 are bonded and fixed together. Seals the internal space and protects it from oxygen, moisture, etc.
The photocurable resin 13 is an ultraviolet curable resin that changes from a liquid to a solid by ultraviolet irradiation and is cured. As a material for the photocurable resin 13, a transparent resin having a transmittance of preferably 80% or more, more preferably 95% or more is cured by irradiation with ultraviolet rays or the like in the entire wavelength region of 380 to 780 nm in the visible light region. Therefore, a photopolymerization initiator added can also be used. Examples of the transparent resin include phenol resin, epoxy resin, acrylic resin, and polyimide resin. Examples of the photopolymerization initiator include acetophenone photopolymerization initiators, benzoin photopolymerization initiators, benzophenone photopolymerization initiators, and thioxanthone photopolymerization initiators. Since the photopolymerization initiator also functions as an ultraviolet absorber, the photocurable resin 13 has a certain degree of ultraviolet absorption even when used alone.

(Configuration of the sealing substrate 12)
The sealing substrate 12 includes a transparent substrate 10 and an ultraviolet absorption film 11. The sealing substrate 12 is bonded to the organic EL element substrate 40 to seal the organic EL display device 1 and protect the organic EL substrate 40 from oxygen and moisture in the air.
As the transparent substrate 10, a glass substrate such as soda lime glass, low alkali borosilicate glass, or non-alkali aluminoborosilicate glass can be used. Further, the transparent oxide semiconductor is generally formed by a forming method such as a sputtering method or an ion plating method. Here, it is also possible to control the absorption spectrum of the film in the formation process.

The ultraviolet absorbing film 11 is formed on the surface of the transparent substrate 10 facing the organic EL element substrate 40. The ultraviolet absorbing film 11 is formed in the same pattern as the pattern of the partition wall 17 of the organic EL element substrate 40. The area of each ultraviolet absorbing film 11 formed on the transparent substrate 10 is preferably larger than the area of the display pixel unit 18.
FIG. 2 is a view showing a pattern example of the ultraviolet absorbing film 11 in comparison with a pattern of the partition wall 17 formed on the organic EL element substrate 40, and FIG. 2 (a) is a first pattern example. FIG. 2B shows a second pattern example.

2A and 2B, the left diagram shows the pattern of the partition wall 17, and the right diagram shows the pattern of the ultraviolet absorbing film 11. 2A and 2B, it can be seen that the pattern of the ultraviolet absorbing film 11 is formed corresponding to the pattern of the partition walls 17. It can also be seen that the area of each ultraviolet absorbing film 11 is larger than the area of the display pixel portion 18.
The pattern of the ultraviolet absorbing film 11 varies depending on the formation pattern of the partition walls 17 of the organic EL element substrate 40, and is not limited thereto.

Examples of the material of the ultraviolet absorbing film 11 include a transparent oxide semiconductor, a material in which an ultraviolet absorbent is dispersed in a photocurable resin 13, and the like, which has absorption in the ultraviolet region and transparency in the visible light region. Can be used. Specific examples include transparent oxide semiconductors such as indium oxide, tin oxide, and zinc oxide, but are not limited thereto.
When a transparent oxide semiconductor is used as the material of the ultraviolet absorption film 11, the transparent oxide semiconductor has an energy gap. Therefore, the transition between the electronic bands absorbs light having an energy larger than the gap, and has an energy smaller than the gap. Does not absorb light. Here, in order to become colorless and transparent (transmit visible light), the energy gap needs to be about 3.3 eV or more. Therefore, by using a transparent oxide semiconductor having an energy gap of about 3.3 eV as the ultraviolet absorbing film 11, ultraviolet light having an energy larger than the gap is absorbed.

The ultraviolet absorbing film 11 has a light transmittance of 80% or more, desirably 90% or more in the visible light region of 380 nm to 780 nm. As a result, light emitted from the light emitting layer can be extracted with high efficiency from the sealing substrate 12 side. In the wavelength region of 200 nm or more and less than 380 nm, the light transmittance is preferably 10% or less, and desirably 5% or less. Thereby, damage to the organic layer 15 due to ultraviolet rays can be suppressed.
The ultraviolet absorbing film 11 can be composed of one or more layers of materials having the above characteristics.

(Method for producing sealing substrate 12)
Next, taking a transparent oxide semiconductor as an example of the material of the ultraviolet absorbing film 11, a photolithography method will be described as an example of a technique for patterning the ultraviolet absorbing film 11 on the transparent substrate 10.
The photolithographic method is a method of transferring a desired geometric pattern shape to a photosensitive material applied in a thin film shape and selectively removing unnecessary portions of the thin film. The photosensitive material used here is called a photoresist (hereinafter referred to as “resist”).

A general resist process proceeds in the order of pretreatment, resist coating, pre-baking, exposure, development, post-baking, etching, and peeling. Details of each step will be described below.
First, a transparent oxide semiconductor is formed on the transparent substrate 10 by a vacuum vapor deposition method or the like.
Next, as a pretreatment, after removing oil and other dirt on the surface of the transparent oxide semiconductor film, it is washed with water and dried. These treatments are important steps for determining the adhesion of the resist to the surface of the transparent oxide semiconductor film, and thus the processing shape.

The resist is applied using, for example, a spin coating method, and the resist film thickness is determined by the resist viscosity and the spin coater rotation speed. Since the resist film thickness depends on the type of resist material, preliminary examination is necessary. Generally, it is used with a film thickness of 1.5-2 μm.
After the resist is applied, pre-baking is performed to remove the solvent from the resist film. However, if the processing temperature is too high, the photosensitive group and the sensitizer are decomposed to cause development failure. Therefore, it is necessary to select an appropriate temperature and time to manage the process.

Next, the resist is exposed through a photomask having openings in a desired pattern. In the exposure of the resist, it is necessary to manage the illuminance and the exposure time suitable for the sensitivity of the resist material to be used. For exposure, a general exposure light source such as a mercury lamp or a metal halide lamp can be used.
After exposure, the resist is developed with a dedicated developer, and then rinsed for stopping development and washing. Next, in the etching process described below, post-baking is added in order to improve the adhesion between the resist and the thin film.

The transparent oxide semiconductor is etched into a predetermined shape using the resist pattern formed in the above-described process. After the etching, the transparent oxide semiconductor can be patterned on the transparent substrate 10 as the ultraviolet absorbing film 11 by thoroughly washing with water and removing the resist.
Through the above process, the sealing substrate 12 in which the ultraviolet absorption film 11 is formed in a pattern corresponding to the display pixel portion 18 can be formed.

(Method for bonding sealing substrate 12 and organic EL element substrate 40)
Next, an example of a method for bonding the sealing substrate 12 obtained as described above to the organic EL element substrate 40 via a photocurable filler will be described.
When manufacturing the organic EL display device 1, for example, a sealing layer (not shown) is provided on the outer peripheral portion of the surface of the sealing substrate 12 facing the organic EL element substrate 40, and the sealing substrate 12 and the organic EL element substrate are provided. A photo-curable filler is filled into the internal space formed when 40 is opposed to each other, and the two substrates are bonded together.

Examples of the photocurable filler include an ultraviolet curable resin that is cured by ultraviolet irradiation. In 1st Embodiment, the photocurable resin 13 hardened | cured by ultraviolet irradiation is used as a photocurable filler. Thereby, the sealing substrate 12 and the organic EL element substrate 40 can be bonded and fixed, and each component can be protected from oxygen and moisture in the air.
When the sealing substrate 12 and the organic EL element substrate 40 are bonded together, first, a sealing layer is applied on the outer periphery of the surface of the sealing substrate 12 on which the ultraviolet absorption film 11 is formed, using a dispenser device. The surface on which the ultraviolet absorbing film 11 of 12 is formed and the surface on which the TFT 30 etc. of the organic EL element substrate 40 are formed are opposed to each other and set in an opposed holder in the vacuum chamber.

Next, the inside of the vacuum chamber is sealed, the exhaust valve is opened, and the inside of the chamber is decompressed to about 1 to 10 Pa.
After the sealing substrate 12 and the organic EL element substrate 40 are opposed to each other, the position of the holder is determined so that each ultraviolet absorption film 11 faces each display pixel unit 18, and then one of the holders is lowered, and the holder After overlapping each other and aligning the same as above again, both substrates are bonded together. After completion of the bonding, the inside of the chamber is returned to atmospheric pressure and taken out, and the photocurable resin 13 is cured by irradiating it with ultraviolet rays from the sealing substrate 12 side under predetermined conditions, and the sealing substrate 12 and the organic EL element substrate 40 is bonded and fixed. In addition, when a heat combined type photocurable filler is used, the heat treatment is performed to spread the polymerization, and the uncured portion can be cured.

In addition, from the viewpoint of preventing the ultraviolet rays 26 incident from the region where the ultraviolet absorption film 11 is not formed from reaching the display pixel unit 18, the surface of the sealing substrate 12 on the organic EL element substrate 40 side after being fixed The distance to the surface of the transparent electrode 14 on the organic EL element substrate 40 is preferably 100 μm or less, preferably 10 μm or less (see FIG. 4).
The sealing layer is formed from an adhesive such as a thermosetting type or an ultraviolet curable type, and includes glass beads, silica beads, and the like. These beads function as a spacer that defines the distance between the substrates when the circularly polarizing plate and the organic EL display substrate are bonded together.

Specifically, spherical spacers such as glass beads and silica beads can be dispersed between both substrates. In addition, a columnar spacer such as an acrylic resin provided on the sealing substrate 12 by a photolithography method or the like can be used.
Further, as another method for fixing the sealing substrate 12 and the organic EL element substrate 40 to face each other, a photocurable adhesive processed into a sheet shape is provided on one substrate, and the sealing substrate 12 and the organic EL substrate 40 are organically bonded. Adhesion with the EL element substrate 40 can be mentioned.

  When the organic EL display device 1 formed as described above is viewed from the sealing substrate 12 side, the display pixel unit 18 is positioned corresponding to the region where the ultraviolet absorption film 11 is formed, and the display pixel unit 18 is It is in a state covered with the ultraviolet absorbing film 11. Specifically, the display pixel unit 18 is in a state of being hidden by the ultraviolet absorption film 11 when irradiated with ultraviolet rays from the viewing side. Further, the partition wall 17 is located corresponding to a region where each ultraviolet absorption film 11 is not formed.

(Operation of the first embodiment)
Next, the operation of the organic EL display device 1 according to the first embodiment will be described with reference to FIG.
In the organic EL display device 1 according to this embodiment, the partition walls 17 that partition the display pixel portions 18 have ultraviolet absorptivity.
Therefore, the ultraviolet rays that reach the partition wall 17 are absorbed, and the ultraviolet light reflected by the partition wall 17 can be prevented from entering the display pixel unit 18.

FIG. 3A is a diagram schematically showing the operation when the partition wall 27 having no ultraviolet absorptivity is used.
In FIG. 3A, the ultraviolet ray 26 irradiated from the sealing substrate 12 side is irradiated with the ultraviolet ray 26 on the display pixel portion 18 located behind the ultraviolet absorbing film 11 because the ultraviolet ray absorbing film 11 blocks the ultraviolet ray 26. It will never be done. Therefore, deterioration of the display pixel unit 18 can be prevented, and light emitted from the display pixel unit 18 is visible through the ultraviolet absorption film 11. On the other hand, the ultraviolet rays 26 enter the organic EL display device 1 from the region where the ultraviolet absorbing film 11 of the sealing substrate 12 is not formed, pass through the photocurable resin 13 and the transparent electrode 14, and the surface of the partition wall 27. Or reflected at the interface such as the bottom of the partition wall 27 and enters the organic EL element substrate 40. The ultraviolet ray 26 propagates while reflecting in the organic EL element substrate 40 and reaches the display pixel unit 18, thereby degrading the organic layer 15 and possibly degrading the organic EL element characteristics.

FIG. 3B is a diagram schematically showing an operation when the organic EL device 1 according to the first embodiment is used.
In FIG. 3B, since the ultraviolet absorbing film 11 blocks the ultraviolet ray 26, the ultraviolet ray 26 is irradiated to the display pixel portion 18 located behind the ultraviolet absorbing film 11, as in the case of FIG. There is nothing. On the other hand, the ultraviolet rays 26 irradiated from the sealing substrate 12 side are incident on the inside of the organic EL display device 1 from the region where the ultraviolet absorbing film 11 of the sealing substrate 12 is not formed. 13 and the transparent electrode 14. However, since the ultraviolet rays 26 are absorbed by the partition walls 17, reflection within the organic EL element substrate 40 can be prevented. Therefore, it is possible to prevent deterioration of the organic layer 15 and the organic EL element characteristics.

In addition, since the internal space between the sealing substrate 12 and the organic EL element substrate 40 is filled with the photocurable resin 13, reflection at the internal space interface is suppressed, and light emission of the light emitting layer is efficiently transmitted. The strength of the organic EL display device 1 is also improved.
Further, in the organic EL display device 1 according to the present embodiment, the distance between the sealing substrate 12 and the transparent electrode 14 is set to a predetermined distance (100 μm) or less.

Thereby, the ultraviolet rays 26 incident from the region where the ultraviolet absorbing film 11 is not formed are prevented from reaching the display pixel unit 18.
FIG. 4A shows the surface of the sealing substrate 12 on the organic EL element substrate 40 side after fixing and the transparent electrode 14 on the organic EL element substrate 40 in the organic EL display device 1 according to the first embodiment. It is the figure which showed typically the effect | action when the distance to the surface was made larger than 100 micrometers.

In FIG. 4A, the ultraviolet ray 26 that has entered the inside of the organic EL display device 1 becomes wider than the partition wall 17 before reaching the organic EL element substrate 40, and irradiates the display pixel unit 18.
FIG. 4B shows the operation when the distance between the surface of the sealing substrate 12 on the organic EL element substrate 40 side after fixing and the surface of the transparent electrode 14 on the organic EL element substrate 40 is 100 μm or less. It is the figure shown typically.
In FIG. 4B, the ultraviolet rays 26 that have entered the inside of the organic EL display device 1 reach the partition wall 17 before being wider than the width of the partition wall 17 and are absorbed by the partition wall 17.

(Effect of 1st Embodiment)
In the organic EL display device 1 according to the first embodiment, when viewed from the sealing substrate 12 side, the display pixel unit 18 is located behind the region where the ultraviolet absorption film 11 is formed, and the display pixel unit 18 absorbs ultraviolet rays. The film 11 is covered. Further, the partition wall 17 is located behind the region where the ultraviolet absorbing film 11 is not formed.

With such a configuration, since the ultraviolet absorption film 11 blocks the ultraviolet light 26, the ultraviolet light 26 is not irradiated to the display pixel portion 18 located behind the ultraviolet absorption film 11. Moreover, since the partition wall 17 absorbs the ultraviolet rays 26 incident from the regions where the respective ultraviolet absorbing films 11 are not formed, the incidence of the ultraviolet rays 26 into the organic EL element substrate 40 can be prevented.
Therefore, the organic EL display device 1 according to the first embodiment is photocured without deteriorating the organic layer 15 and the organic EL element characteristics in the display pixel unit 18 even when the ultraviolet ray 26 is irradiated from the sealing substrate 12 side. The functional resin 13 can be cured.

Furthermore, in the organic EL display device 1 according to the first embodiment, the distance between the surface of the sealing substrate 12 on the organic EL element substrate 40 side after fixing and the surface of the transparent electrode 14 on the organic EL element substrate 40 is the same. It is formed to be 100 μm or less.
With such a configuration, the ultraviolet rays 26 incident from the regions where the respective ultraviolet absorbing films 11 are not formed reach the partition wall 17 before becoming wider than the width of the partition wall 17 and are therefore absorbed by the partition wall 17, so that the organic EL element Incidence into the substrate 40 can be prevented.
Therefore, the organic EL display device 1 according to the first embodiment is photocured without deteriorating the organic layer 15 and the organic EL element characteristics in the display pixel unit 18 even when the ultraviolet ray 26 is irradiated from the sealing substrate 12 side. The functional resin 13 can be cured.

  When the transparent electrode 14 formed on the organic layer 15 has a laminated structure of an electron injection layer and an in-plane conductive layer, an ultraviolet ray is used if the in-plane conductive layer is, for example, an oxide transparent conductive film or a metal thin film. Since it has absorptivity, it absorbs some ultraviolet rays 26. However, since the electron injection layer having a low work function and high reactivity exists immediately below the oxide transparent conductive film or the metal thin film, the organic EL element characteristics are reduced due to chemical alteration and heat generation by the ultraviolet rays 26. The effect of the present invention cannot be obtained.

Examples of the present invention will be described below.
In the organic EL element substrate 40 according to the present embodiment, the TFT 30 is formed in each pixel on the glass substrate 25.
Here, a reflective electrode 16 made of silver is formed as an anode, and an ITO film is formed thereon.

Next, partition walls 17 were formed between the display pixel portions 18 in a matrix so as to cover the ends of the display pixel portions 18. As a material for the partition wall 17, a material obtained by adding 3 wt% of 2- (2′-hydroxy-5′-t-octylphenyl) benzotriazole as an ultraviolet absorber to an ultraviolet curable polyimide resin was used.
A PEDOT: PSS 1.5 wt aqueous solution was formed thereon as a hole transport layer so as to have a film thickness of 40 nm by a spin coating method.

Next, the glass substrate 16 was fixed to a sheet-fed relief printing apparatus, and each color of organic light-emitting ink was printed. The organic light emitting ink was prepared in the following three colors: red (R), green (G), and blue (B).
Red luminescent ink (R): 1% by weight toluene solution of polyfluorene derivative Green luminescent ink (G): 1% by weight toluene solution of polyfluorene derivative Blue luminescent ink (B): 1% toluene by weight of polyfluorene derivative solution

The organic light emitting layer as the organic layer 15 was printed so that the red organic light emitting layer, the green organic light emitting layer, and the blue organic light emitting layer were arranged in a stripe shape.
After printing for each color, it was dried in an oven at 130 ° C. for 1 hour.
After drying, on the organic light emitting layer formed by printing, calcium was formed to a thickness of 4 nm by vapor deposition as a first cathode as the transparent electrode 14 having a low work function so that electrons can be efficiently injected. .
On top of that, aluminum was formed to a thickness of 10 nm as a second cathode as the transparent electrode 14 for improving the in-plane conductivity. Furthermore, a passivation film was formed by forming 200 nm of silicon nitride on the ITO film by CVD.

In the sealing substrate 12 according to this example, an ITO film as the ultraviolet absorption film 11 is formed on a glass substrate as the transparent substrate 10 by using a DC magnetron sputtering method. The transmittance is 85% at 550 nm in the visible light region and 7% at 365 nm in the ultraviolet region.
Here, a resist pattern is formed on the ITO film using a photolithography method, and the ITO is etched by a wet etching method. An aqua regia system (HCl: HNO3: H2O = 1: 0.08: 1, volume ratio) was used as a wet etching solution.

Next, after completion of the etching, the resist film was thoroughly washed and the resist was peeled off, whereby the ITO film was patterned on the transparent substrate 10 as the ultraviolet absorbing film 11. Here, the ITO film pattern was formed to be about 3 μm wide in both vertical and horizontal directions with respect to the pattern size 75 μm × 25 μm of each display pixel portion 18 of the organic EL element substrate 40.
In order to fix the sealing substrate 12 and the organic EL element substrate 40 created as described above to face each other, a sealing layer is applied on the outer periphery of the sealing substrate 12 by a dispenser device, and the inside thereof is photocured. The filler as the functional resin 13 was dropped and the bonding operation was performed in a vacuum chamber. The ultimate pressure in the chamber at this time is 1 Pa.

Next, the bonded substrates were taken out of the chamber and irradiated with ultraviolet rays 26 using an ultraviolet exposure machine. A metal halide lamp was used as the light source of the ultraviolet exposure machine, the illuminance at a wavelength of 365 nm was 100 mW / cm 2, and the exposure amount was 6000 mJ / cm 2.
Furthermore, baking was performed at 80 ° C. for 60 minutes in a clean oven to fix the substrates together. At this time, the distance from the sealing substrate 12 to the surface of the transparent electrode 14 on the organic EL element substrate 40 was 6.0 μm.
When the characteristics of the organic EL display device 1 manufactured as described above were evaluated, the current efficiency was 7.2 cd / A.

(Comparative Example 1)
In the organic EL display device 1 having the above-described structure, when the ultraviolet ray irradiation was performed without providing the ultraviolet absorption film 11 on the sealing substrate 12 and bonding was performed, the current efficiency was 4.4 cd / A, and the ultraviolet absorption film 11 was changed. The organic EL element characteristic was about 61% with respect to the case where the provided sealing substrate 12 was used.
(Comparative Example 2)
In the organic EL display device 1 having the above-described structure, when the partition wall 17 is irradiated with ultraviolet rays without having the ultraviolet absorptivity and bonded, the current efficiency is 5.8 cd / A, and the partition wall 17 has the ultraviolet absorptivity. The characteristic was about 81% as compared with the case of the above.

(Effect of Example)
In the organic EL display device 1 according to the embodiment, when viewed from the sealing substrate 12 side, the display pixel unit 18 is located behind the region where the ultraviolet absorption film 11 is formed, and the display pixel unit 18 is the ultraviolet absorption film 11. It is in a state covered with. Further, the partition wall 17 is located behind the region where the ultraviolet absorbing film 11 is not formed.
With such a configuration, since the ultraviolet absorption film 11 blocks the ultraviolet light 26, the ultraviolet light 26 is not irradiated to the display pixel portion 18 located behind the ultraviolet absorption film 11. Moreover, since the partition wall 17 absorbs the ultraviolet rays 26 incident from the regions where the respective ultraviolet absorbing films 11 are not formed, reflection of the ultraviolet rays 26 into the organic EL element substrate 40 can be prevented.
Therefore, the organic EL display device 1 according to the example does not deteriorate the characteristics of the organic layer 15 and the organic EL element in the display pixel unit 18 even when the ultraviolet ray 26 is irradiated from the sealing substrate 12 side, and the photocurable resin. 13 can be cured.

DESCRIPTION OF SYMBOLS 1 Organic EL display device, 10 Transparent substrate, 11 Ultraviolet absorption film, 12 Sealing substrate, 13 Photocurable resin, 14 Transparent electrode, 15 Organic layer, 16 Reflective electrode, 17 Partition, 18 Display pixel part, 19 Interlayer insulation film , 20 Drain electrode, 21 Source electrode, 22 Semiconductor film, 23 Gate insulating film, 24 Gate electrode, 25 Glass substrate, 26 Ultraviolet light, 27 Partition, 30 TFT, 40 Organic EL element substrate

Claims (6)

A thin film transistor;
A plurality of first electrodes formed on the thin film transistor corresponding to the pixels;
A plurality of partition walls partitioning the first electrode for each pixel;
An organic light emitting layer formed on the first electrode;
A first substrate having a laminated surface on which a second electrode formed on the organic light emitting layer is laminated;
A transparent second substrate on which an ultraviolet absorbing film that transmits light emitted from the organic light emitting layer and absorbs ultraviolet rays is formed on an opposing surface of the first substrate facing the laminated surface;
A photocurable sealing material that bonds the first substrate and the second substrate;
The organic EL display device, wherein the ultraviolet absorbing film formed on the facing surface of the second substrate is provided at a position corresponding to each pixel defined by the partition of the first substrate.   The ultraviolet absorbing film has a region where the light transmittance is 80% or more in a wavelength region of 380 nm or more and 780 nm or less, and has a region where the light transmittance is 10% or less in a wavelength region of 200 nm or more and less than 380 nm. 2. The organic EL display device according to claim 1, wherein the organic EL display device is an ultraviolet absorbing film having visible light permeability.   3. The organic EL display device according to claim 1, wherein a distance between the surface of the sealing substrate on the first substrate side and the first electrode on the first substrate is 100 μm or less.   The organic EL display device according to claim 1, wherein the partition wall is made of an ultraviolet absorbing material.   The partition wall is formed by dispersing an ultraviolet absorber in a photocurable resin, and has a region where the light transmittance is 10% or less in a wavelength region of 200 nm or more and less than 380 nm. 5. The organic EL display device according to any one of 4 above. A first step of forming a thin film transistor on a first substrate;
A second step of forming a plurality of first electrodes corresponding to pixels on the thin film transistor;
A third step of forming a plurality of partitions partitioning the first electrode for each pixel;
A fourth step of forming an organic light emitting layer on the first electrode;
A fifth step of forming a second electrode on the organic light emitting layer;
A second substrate having an ultraviolet absorbing film on a surface of the first substrate facing the surface on which the second electrode is formed, and the ultraviolet absorbing film is provided for each pixel partitioned by the partition wall of the first substrate. A method of manufacturing an organic EL display device, comprising: a sixth step of fixing the first substrate and the second substrate with a photocurable sealing material so as to be in a corresponding position.

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