WO2015190096A1 - Organic el display panel - Google Patents

Abstract

This organic EL display panel is provided with: a substrate; an organic EL element array that is configured from a plurality of organic EL elements that are arranged above the substrate; a sealing plate that is above the organic EL element array and faces the substrate; a sealing wall that is between the substrate and the sealing plate and surrounds the peripheral edge of the organic EL element array to seal the organic EL element array; and a moisture absorbing material that is between the organic EL element array and the sealing wall and surrounds the peripheral edge of the organic EL element array. The moisture absorbing material is a resin that contains a chemical desiccant and is a liquid or a rubber.

Description

Organic EL display panel

The present invention relates to an organic EL display panel using light emission of an organic EL element, and more particularly to a sealing technique for an organic EL display panel.

An organic EL display panel using light emission from an organic EL (Electroluminescence) element is excellent in responsiveness, viewing angle, contrast ratio, impact resistance, etc. Research and development is actively conducted.

In the organic EL display panel, a plurality of organic EL elements are arranged above a substrate such as glass or resin. An organic EL element has a structure in which a functional layer in which an organic light emitting layer is stacked is sandwiched between an electrode pair serving as an anode and a cathode, and by recombination of holes and electrons supplied from the electrode pair in the organic light emitting layer. Emits light.

Organic EL elements often contain materials that easily react with moisture, oxygen, etc., and deteriorate due to contact with moisture, oxygen, etc., resulting in a decrease in luminance and loss of light emitting function. Therefore, in the organic EL display panel, it is important to form a sealing structure that suppresses contact with organic EL elements such as moisture and oxygen from the viewpoint of improving the light emission lifetime.

As a sealing structure of an organic EL display panel, a plurality of organic EL element rows (hereinafter referred to as “organic EL element rows”) are vertically moved with a substrate and a sealing plate using a material having low moisture permeability. A structure sandwiched between the two is generally used. Further, in this configuration, the organic EL element array is sealed by closing the space between the substrate on the side of the organic EL element array and the sealing plate with a sealing wall in which resin or glass frit is cured (for example, , See Patent Document 1).

At this time, since the moisture sealing property of the sealing wall may not be sufficient, a hygroscopic material obtained by curing a resin containing a desiccant or the like is disposed between the organic EL element array and the sealing wall. A configuration is disclosed (for example, see Patent Document 2). Patent Document 2 discloses a configuration in which a chemical desiccant such as an alkali metal oxide or an alkaline earth metal oxide having high reactivity with moisture is used as the desiccant.

JP 2007-59094 A JP 2013-218996 A

However, when a chemical desiccant is used as the desiccant as in the configuration of Patent Document 2, when the moisture absorbent absorbs moisture (moisture absorption), the sealing wall may peel off from the substrate or the sealing plate. There was found.

Accordingly, an object of the present invention is a configuration using a resin containing a chemical desiccant as a hygroscopic material, and an organic EL display panel that can reduce peeling of a sealing wall from a substrate or a sealing plate due to moisture absorption. It is to provide.

An organic EL display panel according to an aspect of the present invention includes a substrate, an organic EL element array including a plurality of organic EL elements arranged above the substrate, and a seal facing the substrate above the organic EL element array. By enclosing the periphery of the organic EL element row between the stop plate and the substrate and the sealing plate, the organic EL element row is sealed between the organic EL element row and the sealing wall. A hygroscopic material surrounding the periphery of the EL element array, and the hygroscopic material is a liquid or rubber-like resin containing a chemical desiccant.

In the organic EL display panel according to the above aspect, since the resin is liquid or rubbery, the chemical desiccant is dissolved in the resin by moisture absorption, and the volume expansion of the moisture absorbent is suppressed. Therefore, in the said organic EL display panel, it can reduce that a sealing wall peels from a board | substrate or a sealing board by moisture absorption.

1 is a schematic block diagram illustrating a configuration of an organic EL display device 1. FIG. 1 is a schematic plan view showing an organic EL display panel 10. FIG. FIG. 3 is a schematic sectional view taken along line XX in FIG. FIG. 4 is a schematic cross-sectional view enlarging Y in FIG. 3. It is a graph explaining the change of the elastic modulus with respect to the temperature of general resin. It is the plane photograph which expanded a part of Example of the organic electroluminescence display panel 10, Comprising: (a) is a photograph before moisture absorption, (b) is a photograph after moisture absorption. It is a schematic cross section which shows the panel 10T used for the water osmosis | permeation experiment. 6 is a graph showing FT-IR measurement results of panel 10T. It is a graph which compares the measurement result of the optical microscope and FT-IR in panel 10T, (a) is a graph in 85 degreeC 85% conditions, (b) is a graph in 60 degreeC 90% conditions. It is a graph which shows the correlation with the light transmittance in a hygroscopic material, and the average particle diameter of a desiccant. 4 is a schematic plan view showing an organic EL display panel 90. FIG. It is the plane photograph which expanded a part of organic electroluminescence display panel 90, (a) is a photograph before moisture absorption, (b) is a photograph after moisture absorption.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The drawings include schematic ones, and the scale and aspect ratio of each member may differ from actual ones.

<Background to the Aspect of the Present Invention>
The inventor of the present application (hereinafter referred to as “the present inventor”), in an organic EL display panel including a hygroscopic material using a chemical desiccant as a desiccant, has a sealing structure due to the volume expansion of the hygroscopic material during moisture absorption. Discovered that it may become impossible to maintain. The contents are shown below.

In the present application, “upper” does not refer to the upward direction (vertically upward) in absolute space recognition, but is based on the relative positional relationship based on the stacking order in the stacked structure of the organic EL display panel. It is specified. Specifically, in the organic EL display panel, the direction perpendicular to the main surface of the substrate and directed from the substrate toward the laminate is defined as the upward direction.

1. Configuration of Organic EL Display Panel 90 First, the present inventor created an organic EL display panel 90 shown in FIG. FIG. 11 is a schematic plan view showing the organic EL display panel 90. In addition, in this application, a top view refers to the figure which looked at the organic electroluminescent display panel from right above, More specifically, the figure which carried out the vertical projection of each member of the organic electroluminescent display panel on the plane parallel to the upper surface of a board | substrate. Say. In addition, the “periphery” in the present application refers to the peripheral edge in the shape of each member in the plan view (hereinafter referred to as “planar shape”).

The organic EL display panel 90 (hereinafter referred to as “panel 90”) includes an organic EL element array 100A, a substrate 101, a sealing plate 112, a sealing wall 113, and a hygroscopic material 914 as main components. Prepare. The organic EL element row 100 </ b> A includes a plurality of organic EL elements (not shown) arranged above the substrate 101. The sealing plate 112 is opposed to the substrate 101 above the organic EL element array 100A. The sealing wall 113 seals the organic EL element row 100 </ b> A by surrounding the periphery 100 </ b> E of the organic EL element row 100 </ b> A between the substrate 101 and the sealing plate 112. The hygroscopic material 914 surrounds the peripheral edge 100E of the organic EL element row 100A between the organic EL element row 100A and the sealing wall 113 (shaded portion in the figure).

In the panel 90, the hygroscopic material 914 is an epoxy resin containing calcium oxide which is a chemical desiccant. Moreover, in the panel 90, the epoxy resin is hardened and glass-like like a general hygroscopic material.

2. Change due to moisture absorption of organic EL display panel 90 Next, the present inventor conducted a storage test in a high-temperature and high-humidity environment for the created panel 90 in order to confirm the state change before and after moisture absorption. In the test, the panel 90 was stored in an environment of 60 ° C. and 90% for about 1000 hours.

FIG. 12 is an enlarged plan view of a part of the panel 90, where (a) is a photograph before moisture absorption and (b) is a photograph after moisture absorption. FIG. 12 is a photograph of the portion corresponding to the corner of the planar shape of the panel 90 taken from directly above.

12A, in the panel 90 before moisture absorption, it can be seen that the sealing wall 113 is in a relatively uniform transparent state and is in close contact with the substrate 101 and the sealing plate 112. On the other hand, as shown in FIG. 12B, in the panel 90 after moisture absorption, a shadow is generated on the inner portion of the sealing wall 113, and in particular, linear wrinkles are generated as indicated by R in the figure. . This indicates that, in this portion, the sealing wall 113 is peeled off from the substrate 101 or the sealing plate 112 to form a space, and the light transmittance is changed. That is, in the panel 90, it can be seen that the sealing wall 113 is separated from the substrate 101 or the sealing plate 112 due to moisture absorption.

This peeling is caused by volume expansion due to moisture absorption of calcium oxide in the moisture absorbent 914. Specifically, in the panel 90, the penetration of moisture or the like into the organic EL element array 100 </ b> A is suppressed by adsorbing moisture or the like that penetrates beyond the sealing wall 113 by the calcium oxide in the hygroscopic material 914. . At this time, the calcium oxide in the moisture absorbent material 914 that has absorbed moisture becomes calcium hydroxide by a chemical reaction with moisture. 1 mol of calcium oxide reacts with moisture to give 1 mol of calcium hydroxide, but the volume per mol is about 16.7 cm ³ for calcium oxide and about ³ times as high as 33.5 cm ³ for calcium hydroxide. . Accordingly, the hygroscopic material 914 expands in volume due to moisture absorption. Then, the space between the substrate 101 and the sealing plate 112 is widened by the pressure when the hygroscopic material 914 is volume-expanded, and the sealing wall 113 is peeled off from the substrate 101 or the sealing plate 112.

Although the sealing wall 113 does not completely suppress moisture permeation, the moisture absorption rate of the moisture absorbent 914 is reduced by suppressing moisture permeation to a certain extent. On the other hand, when peeling of the sealing wall 113 from the substrate 101 or the sealing plate 112 occurs, a large amount of moisture enters from the peeling portion and the moisture absorption rate of the moisture absorbent 914 increases. As a result, the moisture absorption capacity of the moisture absorbing material 914 is saturated, and the organic EL element is rapidly deteriorated. Further, the substrate 101, the sealing plate 112, or the sealing wall 113 may be damaged by peeling, and the reliability of the panel 90 may be reduced.

Note that the physical desiccant that takes moisture into pores in the molecule does not easily expand in volume due to moisture absorption, but the chemical desiccant generally expands in volume as hydroxide or hydrate due to moisture absorption. To do. Therefore, the above peeling can occur not only in the moisture absorbent material 914 containing calcium oxide but also in general organic EL display panels including a moisture absorbent material using a chemical desiccant. On the other hand, the use of a chemical desiccant that is highly reactive with moisture is expected in organic EL display panels that require minimization of the volume of each member in order to reduce the thickness and frame.

As described above, the present inventor has described a book described below in order to reduce the separation of the sealing wall from the substrate or the sealing plate due to moisture absorption in the configuration using the resin containing the chemical desiccant as the moisture absorbing material. It came to one aspect of the invention.

<Outline of One Embodiment of the Present Invention>
An organic EL display panel according to an aspect of the present invention includes a substrate, an organic EL element array including a plurality of organic EL elements arranged above the substrate, and a seal facing the substrate above the organic EL element array. By enclosing the periphery of the organic EL element row between the stop plate and the substrate and the sealing plate, the organic EL element row is sealed between the organic EL element row and the sealing wall. A hygroscopic material surrounding the periphery of the EL element array, and the hygroscopic material is a liquid or rubber-like resin containing a chemical desiccant.

In addition, the organic EL display panel according to another aspect of the present invention has a property that the hygroscopic material becomes transparent by moisture absorption in the above-described configuration.

Further, in the organic EL display panel according to another aspect of the present invention, in the above configuration, the chemical desiccant is ionized in the resin by moisture absorption.

In the organic EL display panel according to the above aspect, since the resin is liquid or rubbery, the chemical desiccant is dissolved in the resin by moisture absorption, and the volume expansion of the moisture absorbent is suppressed. Therefore, in the said organic EL display panel, it can reduce that a sealing wall peels from a board | substrate or a sealing board by moisture absorption.

In the organic EL display panel according to another aspect of the present invention, the chemical desiccant is a powder of an oxide of an alkali metal element or an alkaline earth metal element in the above configuration. In the organic EL display panel according to the aspect described above, the hydroxide of the alkali metal element or alkaline earth metal element generated by moisture absorption is dissolved in the resin, so that the volume expansion of the moisture absorbent is suppressed. Therefore, in the said organic EL display panel, it can reduce that a sealing wall peels from a board | substrate or a sealing board by moisture absorption.

In the organic EL display panel according to another aspect of the present invention, the average particle diameter of the chemical desiccant is 500 nm or more in the above aspect. In the organic EL display panel according to the above aspect, the excessive activity improvement due to the increase in the specific surface area of the chemical desiccant can be suppressed and the amount of moisture absorption during production can be reduced, so that the function of the moisture absorbent at the time of completion of the panel is ensured. be able to.

In the organic EL display panel according to another aspect of the present invention, the resin has a viscosity of 10 Pa · s to 10,000 Pa · s in the above aspect. In the organic EL display panel according to the above aspect, moisture diffusion in the resin can be suppressed, and fluidity during production can be ensured.

In the organic EL display panel according to another aspect of the present invention, the resin is a non-curable resin in the above aspect. In the organic EL display panel which concerns on the said aspect, it can suppress that resin changes in quality and becomes glassy by the influence of the heat at the time of manufacture or use, light, or a hardening | curing agent.

In the organic EL display panel according to another aspect of the present invention, the resin is composed of molecules having polarity in the above aspect. In the organic EL display panel according to the above aspect, the hydrogen bond between the chemical desiccant after moisture absorption and the molecules constituting the resin is strengthened, and the state after ionization of the chemical desiccant is further stabilized. The desiccant becomes easier to dissolve in the resin.

In the organic EL display panel according to another aspect of the present invention, the content of the chemical desiccant in the resin is 10% by weight or more and 60% by weight or less in the above configuration. In the organic EL display panel according to the above aspect, the hygroscopic capacity of the hygroscopic material is ensured, and the chemical desiccant is easily dispersed in the resin.

In the organic EL display panel according to another aspect of the present invention, the hygroscopic material is in close contact with the sealing plate in the above configuration. In the organic EL display panel according to the above aspect, the moisture passage is blocked, and the penetration of moisture into the organic EL element array can be further suppressed. In the organic EL display panel according to the above aspect, the gap between the sealing plate and the hygroscopic material can be reduced, which is advantageous for thinning.

In addition, an organic EL display panel according to another aspect of the present invention further includes an inorganic material, a thin film sealing layer that covers the upper and peripheral edges of the organic EL element array, a glassy resin, and a thin film. A resin layer disposed between the sealing layer and the sealing plate, the outer periphery of the hygroscopic material is in close contact with the sealing wall, and the inner periphery of the hygroscopic material is in close contact with the thin film sealing layer and the resin layer To do.

In the organic EL display panel according to the above aspect, the hygroscopic material is sandwiched between a solid or glass-like sealing wall, a thin film sealing layer, and a resin layer, and the shape of the hygroscopic material is stabilized. Furthermore, when the moisture absorbing material is in close contact with the sealing wall, the thin film sealing layer, and the resin layer, the gap in the frame region can be reduced, which is advantageous for forming a sandwiched frame. In addition, the moisture passage around the hygroscopic material is closed by close contact, and the penetration of moisture into the organic EL element array can be further suppressed.

<Embodiment>
Below, the organic electroluminescence display 1 using the organic electroluminescence display panel 10 which concerns on embodiment as one aspect | mode of this invention is demonstrated.

1. Overall Configuration of Organic EL Display Device 1 FIG. 1 is a block diagram showing the overall configuration of the organic EL display device 1. The organic EL display device 1 is a display device used for, for example, a commercial display such as a television, a personal computer, a portable terminal, an electronic signboard, and a large screen. The organic EL display device 1 includes an organic EL display panel 10 and a drive control unit 20 that is electrically connected to the organic EL display panel 10.

Organic EL display panel 10 (hereinafter referred to as “panel 10”) is a display panel having a rectangular image display surface (not shown). In the panel 10, a plurality of organic EL elements (not shown) are arranged along the image display surface, and an image is displayed by a combination of light emission of the organic EL elements. As an example, the panel 10 employs a top emission type and an active matrix system.

The drive control unit 20 includes a drive circuit 21 connected to the panel 10 and a control circuit 22 connected to the external device and the drive circuit 21. The drive circuit 21 is a power supply circuit that supplies power to each organic EL element, a signal circuit that applies a voltage signal that controls the power supplied to each organic EL element, and a scan that switches between locations where the voltage signal is applied at regular intervals. Circuit and the like. The control circuit 22 controls the operation of the drive circuit 21 according to data including image information input from the outside.

In FIG. 1, four drive circuits 21 are arranged around the panel 10, but the configuration of the drive control unit 20 is not limited to this, and the number and position of the drive circuits 21 can be changed as appropriate. It is.

2. Configuration of Panel 10 (1) Plane Configuration FIG. 2 is a schematic plan view showing the panel 10. The panel 10 includes an organic EL element array 100A, a substrate 101, a sealing plate 112, a sealing wall 113, and a hygroscopic material 114 as main components. The organic EL element array 100A is composed of a plurality of organic EL elements 100 (not shown) arranged above the substrate 101. Therefore, the peripheral edge 100E of the organic EL element row 100A indicated by the two-dot chain line in FIG. 2 corresponds to the peripheral edge of the image display surface of the panel 10.

The sealing plate 112 is opposed to the substrate 101 above the organic EL element array 100A. The sealing wall 113 seals the organic EL element array 100 </ b> A by surrounding the periphery 100 </ b> E between the substrate 101 and the sealing plate 112. The hygroscopic material 114 surrounds the peripheral edge 100E between the organic EL element row 100A and the sealing wall 113 (shaded portion in the figure).

In addition, since the panel 10 is a top emission system, an image is displayed on the upper surface side (sealing plate 112 side) shown in FIG.

(2) Cross-sectional Configuration FIG. 3 is a schematic cross-sectional view along the line XX in FIG. The cross-sectional configuration of the panel 10 includes a substrate 101, a TFT layer 102, a passivation layer 103, an interlayer insulating layer 104, a pixel electrode 105, a functional layer 106, a common electrode 107, a partition wall 108, and a thin film sealing layer. 109, a resin layer 110, a color filter layer 111, and a sealing plate 112. In the panel 10, one set of the pixel electrode 105, the functional layer 106, and the common electrode 107 constitutes the organic EL element 100, and a plurality of arranged organic EL elements 100 constitute the organic EL element row 100 </ b> A. Further, a hygroscopic material 114 and a sealing wall 113 are arranged in this order on the peripheral edge 100E (not shown) side of the organic EL element array 100A.

(3) Description of each part a. Substrate 101
The substrate 101 is a flat member, and has a role of a support material for arranging other components in the panel 10. Further, the substrate 101 seals the lower part of the organic EL element array 100A as a part of the sealing structure.

For the substrate 101, a material having electrical insulation or a semiconductor material such as silicon can be used. Alternatively, a metal material such as aluminum or stainless steel coated with a material having electrical insulation may be used. Examples of the material having electrical insulation include glass materials such as alkali-free glass, soda glass, non-fluorescent glass, phosphate glass, borate glass, and quartz glass. In addition, the material may be a resin material such as an acrylic resin, a styrene resin, a polycarbonate resin, an epoxy resin, a polyethylene resin, a polyester resin, a polyimide resin, or a silicone resin. Further, the material may be a metal oxide material such as aluminum oxide.

Note that since the substrate 101 is a part of the sealing structure, it is preferable to use a material with low moisture permeability, such as glass or metal. Alternatively, a resin material whose upper surface is coated with a thin film with low moisture permeability such as silicon nitride, silicon oxide, silicon oxynitride, or aluminum oxide may be used.

b. TFT layer 102
The TFT layer 102 is an electronic circuit layer disposed on the substrate 101, and a power supply circuit and a control circuit for supply power to each organic EL element are formed. Specifically, the TFT layer 102 is a stack of a semiconductor layer, a conductor layer, and an insulator layer disposed on the substrate 101, and an electronic circuit such as a TFT (Thin Film Transistor) element (not shown) is formed by the stack configuration. An element is formed.

The semiconductor layer in the TFT layer 102 includes, for example, a general semiconductor material such as silicon, an oxide semiconductor material such as indium-zinc-gallium oxide, and a π-electron conjugated system extending in the plane direction such as a polycyclic aromatic compound. An organic semiconductor material or the like can be used. For the conductor layer, for example, a metal material such as aluminum, copper, or gold, a carbon material such as graphite or carbon nanotube, or a conductive oxide material such as indium tin oxide (ITO) or indium zinc oxide (IZO) is used. be able to. For the insulator layer, for example, inorganic materials such as silicon nitride, silicon oxide, silicon oxynitride, and aluminum oxide, and organic materials such as acrylic resin, polyimide resin, siloxane resin, and phenol resin can be used.

For example, the following method can be used to form the TFT layer 102. First, a thin film of a semiconductor material, a conductor material, or an insulator material is formed over the substrate 101 by a sputtering method, a CVD (Chemical Vapor Deposition) method, a spin coating method, or the like. Then, the thin film is patterned into a predetermined shape by a photolithography method or the like. The TFT layer 102 can be formed by repeating this process and forming a stack of a semiconductor layer, a conductor layer, and an insulator layer so as to constitute a predetermined electronic circuit.

c. Passivation layer 103
The passivation layer 103 is a thin film layer disposed so as to cover the TFT layer 102, and has a role of protecting the electronic circuit in the TFT layer 102 from physical and chemical changes. Further, the passivation layer 103 may have a role of electrically insulating the electronic circuits of the TFT layer 102 from each other.

For the passivation layer 103, an inorganic material such as silicon nitride, silicon oxide, or silicon oxynitride, or a metal oxide material such as aluminum oxide can be used. As a method for forming the passivation layer 103, for example, a thin film of the above material may be formed by a sputtering method, a CVD method, a spin coating method, or the like so as to cover the TFT layer 102.

d. Interlayer insulating layer 104
The interlayer insulating layer 104 is a layer disposed on the passivation layer 103 and has a role of electrically insulating the organic EL element 100 and the TFT layer 102. In addition, the interlayer insulating layer 104 has a role of flattening irregularities generated by the TFT layer 102 in order to form the organic EL element 100 stably and with high accuracy. Although not shown in FIG. 3, through-holes (contact holes) are formed in the passivation layer 103 and the interlayer insulating layer 104, and each organic EL element 100 and a predetermined portion of the TFT layer 102 are connected to each other. Electrically connected.

The interlayer insulating layer 104 can be made of an electrically insulating material that can impart a certain fluidity during the manufacturing process, for example, an organic material such as an acrylic resin, a polyimide resin, a siloxane resin, or a phenol resin. As a method for forming the interlayer insulating layer 104, for example, the organic material may be applied to the entire surface of a predetermined region on the passivation layer 103 by various application methods.

e. Pixel electrode 105
The pixel electrode 105 is a plurality of rectangular electrodes arranged on the interlayer insulating layer 104, and serves as an anode that supplies holes to the functional layer 106 by power supplied through the TFT elements of the TFT layer 102. Have a role. The pixel electrode 105 is one of the components of the organic EL element 100, and defines a region of the organic EL element 100 in the image display surface, that is, a pixel region.

For the pixel electrode 105, a conductive material can be used. For example, a metal material such as aluminum, silver, molybdenum, tungsten, titanium, chromium, nickel, or zinc, an alloy material that is a combination of metal materials, or a conductive oxide material such as ITO or IZO can be used. Moreover, the multilayer structure etc. which laminated | stacked these may be sufficient. In particular, when a conductive oxide material is stacked on a metal material or an alloy material, oxidation of the metal material or the alloy material can be prevented.

Note that it is preferable to use a material having a high work function for the pixel electrode 105 from the viewpoint of hole injection. Since the panel 10 is a top emission type, it is preferable to use a light reflective material for the pixel electrode 105. In the case where a material that does not have light reflectivity is used for the pixel electrode 105, it is preferable to coat the pixel electrode 105 with a light reflective material.

As a method for forming the pixel electrode 105, for example, a dry process such as a vacuum evaporation method, an electron beam evaporation method, a sputtering method, a reactive sputtering method, an ion plating method, a vapor phase growth method, or the like can be used. It is preferable to use it. Further, a printing method, a spin coating method, an ink jet method, or the like may be used.

f. Functional layer 106
The functional layer 106 is a layer disposed on the pixel electrode 105, is one of the components of the organic EL element, and includes at least an organic light emitting layer. The organic light emitting layer is a portion where light emission (electroluminescence phenomenon) is performed by recombination of holes and electrons supplied from the pixel electrode 105 and the common electrode 107.

An organic material that emits light by an electroluminescence phenomenon is used for the organic light emitting layer. Specifically, for example, oxinoid compounds, perylene compounds, coumarin compounds, azacoumarin compounds, oxazole compounds, oxadiazole compounds, perinone compounds, pyrrolopyrrole compounds, naphthalene compounds, anthracene compounds, fluorene compounds, fluoranthene compounds, tetracene compounds, pyrenes Compound, coronene compound, quinolone compound, azaquinolone compound, pyrazoline derivative, pyrazolone derivative, rhodamine compound, chrysene compound, phenanthrene compound, cyclopentadiene compound, stilbene compound, diphenylquinone compound, styryl compound, butadiene compound, dicyanomethylenepyran compound, dicyanomethylene Thiopyran compounds, fluorescein compounds, pyrylium compounds, thiapyrylium compounds, serenapyrine Compounds, telluropylium compounds, aromatic ardadiene compounds, oligophenylene compounds, thioxanthene compounds, cyanine compounds, acridine compounds, metal complexes of 8-hydroxyquinoline compounds, metal complexes of 2-bipyridine compounds, Schiff salts and group III metals Known fluorescent materials and phosphorescent materials such as fluorescent materials such as complexes, oxine metal complexes, and rare earth complexes (all described in JP-A-5-163488) can be used. Further, for example, a mixed layer of an organic compound using the above-described fluorescent substance or phosphorescent substance as a dopant may be used.

As a method for forming the organic light emitting layer, various coating methods such as a printing method, a spin coating method, and an ink jet method can be used. Alternatively, a dry process such as a vacuum evaporation method, an electron beam evaporation method, a sputtering method, a reactive sputtering method, an ion plating method, or a vapor phase growth method can be used. From the viewpoint of material cost and formation accuracy, it is preferable to use a coating method.

In addition to the organic light emitting layer, the functional layer 106 is a hole / electron injection layer, a hole / electron transport layer, a hole / electron blocking layer for the purpose of low voltage driving, high light emission efficiency, and long life of the organic EL element. It may have a layer or the like. A known method can be used as the arrangement configuration, material, and formation method.

g. Common electrode 107
The common electrode 107 is a rectangular electrode disposed so as to cover all of the partition wall 108 between the functional layer 106 and the functional layer 106, and is applied to the functional layer 106 by the power supplied via the TFT element of the TFT layer 102. It serves as a cathode for supplying electrons. The common electrode 107 is one of the components of the organic EL element 100 and is shared by each organic EL element 100.

The common electrode 107 can be made of a conductive material as with the pixel electrode 105. Specifically, it is a transparent conductive oxide material such as ITO or IZO. Moreover, you may laminate | stack the layer of metals, such as silver, gold | metal | money, platinum, palladium, nickel, copper, aluminum, or these alloys in the layer which consists of a transparent conductive oxide material.

Note that it is preferable to use a material having a low work function for the common electrode 107 from the viewpoint of electron injection. Further, since the panel 10 is a top emission type, it is preferable to use a material having high light transmittance for the common electrode 107.

As the method for forming the common electrode 107, for example, the method exemplified as the method for forming the pixel electrode 105 can be used.

h. Bulkhead 108
The partition wall 108 is a layer arranged so as to separate the pixel electrode 105 and the functional layer 106, and has a role of physically defining each organic EL element 100 and electrically insulating it. The shape of the partition 108 may be a lattice shape (pixel bank) partitioned for each organic EL element 100 or a line shape (line bank) partitioned for each column of the organic EL elements 100.

The partition wall 108 may be made of a material that has electrical insulation and can form a fine pattern by processing. For example, the organic materials exemplified as the material for the interlayer insulating layer 104 can be used. Note that the material of the partition wall 108 is preferably a material which has resistance to an organic solvent and does not excessively deform or change in quality with respect to an etching process or a baking process. Moreover, when using the apply | coating method for formation of an organic light emitting layer, it is preferable to perform a fluorine process etc. on the surface of a partition and to make liquid repellency.

As a method for forming the partition wall 108, for example, a photosensitive resin is applied to the interlayer insulating layer 104 on which the pixel electrode 105 is formed by various coating methods, and patterning is performed so as to open the pixel electrode 105 by a photolithography method. That's fine.

i. Thin film sealing layer 109
The thin film sealing layer 109 is made of an inorganic material, and is a thin film that covers the upper and peripheral edges of the organic EL element array 100 </ b> A, specifically, the laminate on the substrate 101 from the TFT layer 102 to the partition wall 108 in the panel 10. The thin film sealing layer 109 has a role of protecting each laminate before forming the sealing structure and suppressing penetration of moisture and the like from inside and outside the sealing structure after forming the sealing structure.

For the thin film sealing layer 109, it is preferable to use a material having low permeability such as moisture and oxygen, that is, a material having a dense structure. In particular, the material of the thin film sealing layer 109 is preferably an oxide, nitride, or oxynitride of silicon, carbon, or aluminum. Specifically, for example, silicon nitride, silicon oxide, silicon oxynitride, carbon oxide, carbon nitride, aluminum oxide, or the like can be used. In addition, since the panel 10 is a top emission type, it is preferable to use a material having a high light transmittance and a small difference in refractive index between the adjacent common electrode 107 and the resin layer 110 for the thin film sealing layer 109.

As a method for forming the thin film sealing layer 109, a dry process such as a vacuum evaporation method, an electron beam evaporation method, a sputtering method, a reactive sputtering method, an ion plating method, or a vapor deposition method can be used. The method is preferably used.

j. Resin layer 110
The resin layer 110 is a layer disposed between the thin film sealing layer 109 and the sealing plate 112. Specifically, the resin layer 110 is surrounded by the thin film sealing layer 109, the color filter layer 111, and the hygroscopic material 114 in the panel 10. This is a resin layer filled in the region. The resin layer 110 has a role of improving the adhesion between the substrate 101 and the sealing plate 112 and improving the strength of the panel 10.

For the resin layer 110, for example, a curable resin such as an epoxy resin, an acrylic resin, or a silicone resin can be used. Further, since the panel 10 is a top emission type, the resin layer 110 has a high light transmittance like the thin film sealing layer 109, and there is a difference in refractive index between the adjacent thin film sealing layer 109 and the color filter layer 111. It is preferable to use a small material.

For example, the following method can be used to form the resin layer 110. First, a curable resin is uniformly applied on the thin film sealing layer 109 or the sealing plate 112 on which the color filter layer 111 is arranged by various application methods such as a dispensing method, a printing method, and a die coating method. Then, after the substrate 101 and the sealing plate 112 are bonded together, the resin layer 110 can be formed by curing the curable resin with heat, light, or a curing agent.

k. Color filter layer 111
The color filter layer 111 is an optical filter disposed above the functional layer 106 and the partition wall 108 and adjusts the chromaticity of light emitted from the functional layer 106 and the contrast in the image display surface of the panel 10. The color filter layer 111 includes a color filter 111C, a black matrix 111B, and a dummy filter 111D.

The colored filter 111C is a colored (red, green, blue, etc.) filter disposed above the functional layer 106 (organic EL element 100) and has a function of improving the color purity of light emitted from the functional layer 106. . The black matrix 111 </ b> B is a black resin disposed at the interval between the colored filters 111 </ b> C and the peripheral edge portion of the color filter layer 111, and has functions of suppressing reflection of external light and improving contrast. The dummy filter 111D is a filter disposed outside the peripheral edge 100E of the organic EL element array 100A, and is for suppressing the formation failure of each member that easily occurs in the vicinity of the peripheral edge 100E.

A known organic material such as a commercially available color resist can be used for the colored filter 111C. For the black matrix 111B, a light-shielding material such as an organic material containing a black pigment can be used. For the dummy filter 111D, for example, the same material as the colored filter 111C can be used.

Various coating methods can be used for forming the color filter layer 111. For example, an organic material layer containing a black pigment is first formed on the sealing plate 112 by a coating method, and openings are formed at positions corresponding to the organic EL elements 100 and positions where the dummy filter 111D is formed by photolithography. Next, the color filter layer 111 can be formed by applying an organic solution containing the material of the colored filter 111C to the opening and drying the solvent of the organic solution.

l. Sealing plate 112
The sealing plate 112 is a flat member and has a role of sealing the upper part of the organic EL element row 100A as a part of the sealing structure. Further, the sealing plate 112 may have a role as a support material for the resin layer 110, the color filter layer 111, the sealing wall 113, the hygroscopic material 114, and the like.

For the sealing plate 112, for example, the materials exemplified as the material of the substrate 101 can be used. Further, since the sealing plate 112 is a part of the sealing structure, it is preferable to use a material with low moisture permeability, such as glass or metal. Alternatively, a resin material whose upper surface is coated with a thin film with low moisture permeability such as silicon nitride, silicon oxide, silicon oxynitride, or aluminum oxide may be used. Moreover, in the panel 10 of the top emission type, the sealing plate 112 preferably has high light transmittance.

m. Sealing wall 113
The sealing wall 113 is a wall-like member disposed on the passivation layer 103 and the thin film sealing layer 109 on the substrate 101 so as to surround the peripheral edge 100E of the organic EL element row 100A. The sealing wall 113 has a role of sealing the side of the organic EL element row 100A as a part of the sealing structure.

For the sealing wall 113, for example, a curable resin such as an epoxy resin, a urethane resin, or an acrylic resin can be used. For example, when a glass material is used for the substrate 101 and the sealing plate 112, a glass frit that can be welded thereto can be used. Note that if the sealing wall 113 contains a spacer having a certain rigidity, the distance between the substrate 101 and the sealing plate 112 can be maintained. Further, since the sealing wall 113 is a part of the sealing structure, it is preferable to use a material having low moisture permeability.

For example, the following method can be used to form the sealing wall 113. First, a curable resin is applied in a rectangular frame shape to the peripheral region of the substrate 101 or the sealing plate 112 by various application methods such as a dispensing method, a printing method, and a die coating method. Then, after the substrate 101 and the sealing plate 112 are bonded together, the sealing wall 113 can be formed by curing the curable resin with heat, light, or a curing agent.

n. Hygroscopic material 114
The hygroscopic material 114 is a member disposed on the thin film sealing layer 109 on the substrate 101 along the inner side of the sealing wall 113, and adsorbs moisture or the like that has passed through the sealing wall 113 to form an organic EL element array. It has a role of suppressing penetration into 100A. The hygroscopic material 114 also has a role of adsorbing moisture contained in each member (for example, the resin layer 110 and the color filter layer 111) of the panel 10 in the manufacturing process.

FIG. 4 is an enlarged schematic cross-sectional view of Y in FIG. The hygroscopic material 114 is a resin 114b containing a chemical desiccant 114a. The chemical desiccant 114a is in a powder form and has a function of adsorbing moisture by chemically reacting with moisture or the like that has passed through the sealing wall 113. The resin 114b is a liquid or rubber-like substance as will be described later, and contains a chemical desiccant 114a dispersed therein as a binder.

As the chemical desiccant 114a, for example, a powder such as an oxide of alkali metal or alkaline earth metal having high reactivity with moisture can be used. Specifically, it is a powder of lithium oxide, sodium oxide, potassium oxide, calcium oxide, magnesium oxide, calcium oxide, strontium oxide, barium oxide or the like. In addition, other known chemical desiccants such as calcium chloride, calcium sulfate, magnesium perchlorate, magnesium sulfate, potassium carbonate, potassium hydroxide, sodium hydroxide, sodium sulfate, phosphorus oxide, zinc chloride, etc. The powder may be used.

Examples of the resin 114b include epoxy resins, acrylic resins, silicone resins, urethane resins, phenol resins, polyester resins, ethylene / vinyl acetate copolymer resins, polyvinyl alcohol resins, polyisobutylene resins, polybutene resins, polybutadiene resins, polyimide resins, Polyimide silicone resin, polystyrene resin, terpene resin, hydrofluoroether resin and the like can be used.

The viscosity of the resin 114b is preferably 10 Pa · s or more and 10,000 Pa · s or less. When the viscosity is 10 Pa · s or more, the diffusion of moisture in the resin 114 b can be suppressed, and when the viscosity is 10,000 Pa · s or less, the substrate 101 and the sealing plate 112 are particularly stuck during manufacturing. The liquidity at the time of combination can be secured. A particularly preferable range of the viscosity of the resin 114b is 100 Pa · s or more and 2,000 Pa · s or less.

The material of the resin 114b preferably has a molecular weight of 100 or more and 10,000 or less. By being in this range, a resin 114b having a preferable viscosity can be obtained.

Further, it is preferable that the resin 114b is not diluted with a solvent, such as a solventless type. When not diluted with a solvent, a drying process is not required when the moisture absorbent material 114 is formed, and the number of steps can be reduced, and deterioration of the organic EL element 100 due to the remaining solvent can be reduced.

In the hygroscopic material 114, the content of the chemical desiccant 114a in the resin 114b is preferably 10% by weight or more and 60% by weight or less. When the content of the chemical desiccant 114a is 10% by weight or more, the hygroscopic capacity of the hygroscopic material 114 is ensured. Moreover, when the content of the chemical desiccant 114a is 60% by weight or less, the chemical desiccant 114a is easily dispersed in the resin 114b.

Here, the resin 114b is liquid or rubbery as described above. FIG. 5 is a graph for explaining the change of the elastic modulus with respect to the temperature of a general resin. The horizontal axis in FIG. 5 indicates the temperature, Tg indicates the glass transition temperature of the resin, and Tm indicates the melting point of the resin. The vertical axis | shaft of FIG. 5 has shown the elasticity modulus (Young's modulus), and shows that the distortion | strain with respect to stress becomes small, so that it is upward.

In general, a resin has a very large elastic modulus E1 at a low temperature below the glass transition temperature Tg and hardly deforms even when stress is applied (glassy state). The elastic modulus begins to decrease suddenly (transition state). When the temperature is further increased, the decrease in the elastic modulus of the resin stops at a certain temperature and becomes a constant elastic modulus E2, which is deformed by stress but does not flow (rubbery). When the temperature is further raised and the melting point Tm is exceeded, the elastic modulus decreases again, and the resin enters a fluid state (liquid state) that does not undergo elastic deformation. The glass transition temperature Tg is a temperature that is an intermediate point of the transition state, and is intermediate between a temperature at which the elastic modulus starts to decrease suddenly and a temperature at which the decrease in the elastic modulus stops thereafter when the resin temperature rises. Temperature.

The above glass transition temperature Tg and melting point Tm vary depending on the resin. Therefore, the resin 114b being liquid or rubbery means that the glass transition temperature Tg of the resin 114b is lower than the operating temperature range of the panel 10 (for example, 0 ° C. or higher and 40 ° C. or lower). The melting point Tm of the resin 114b need not have a specific relationship with the operating temperature range of the panel 10, but the melting point Tm is lower than the operating temperature range (always liquid) or the melting point Tm is higher than the operating temperature range ( (Always rubbery) and the hygroscopic material 114 is stable because it is preferable.

Also, from the viewpoint of the molecular motion of the resin, in a glassy resin having a glass transition temperature Tg or lower, the molecules are restrained in motion by cross-linking between molecules or between molecules, and only perform thermal vibration. In the case of a rubber-like resin having a glass transition temperature exceeding Tg, some of the crosslinks are weakened, and the molecule cannot move as a whole molecule, but can rotate within the molecule (microscopically). Brown movement). In a liquid resin exceeding the melting point Tm, cross-linking between molecules is weakened, and molecules can move freely (Brownian motion). Therefore, the resin 114b is rubbery when the molecules in the resin are in a state where only micro-Brownian motion is possible, and the resin 114b is in liquid state when the molecules in the resin are in a state where Brownian motion is possible. .

For example, the following method can be used to form the moisture absorbent material 114. First, an uncured epoxy resin containing calcium oxide powder is sealed with the material of the resin layer 110 applied to the substrate 101 or the sealing plate 112 by various application methods such as a dispensing method, a printing method, and a die coating method. It is applied at a distance from the material of the stop wall 113. At this time, the epoxy resin is not added with a curing initiator. And after bonding the board | substrate 101 and the sealing board 112, the material of the resin layer 110 and the material of the sealing wall 113 are hardened with a heat | fever, an ultraviolet-ray, etc., and a sealing structure is formed. Since the epoxy resin does not contain a curing initiator, it is not cured even when irradiated with heat or ultraviolet rays, and can maintain a liquid or rubbery state. Thereby, the liquid or rubber-like hygroscopic material 114 can be disposed between the organic EL element array 100 </ b> A and the sealing wall 113.

Note that when the resin 114b of the hygroscopic material 114 has a certain viscosity or higher, a certain shape can be maintained even if it is liquid, so the hygroscopic material is applied before the material of the resin layer 110 or the sealing wall 113 is applied. The material 114 may be applied.

In addition, when the resin 114b is a curable resin, the resin 114b may be altered and become glassy due to the influence of heat, light, or a curing agent when the panel 10 is manufactured or used. Therefore, the resin 114b is preferably a non-curable resin. The non-curable resin includes a resin that is curable by addition of a curing initiator and has no curing initiator added, such as the above-described epoxy resin.

3. Verification Test (1) Storage Test According to Examples The inventor actually manufactured the example of the panel 10 described above, and performed a storage test for confirming the state change before and after moisture absorption as with the panel 90. In the examples, calcium oxide powder having an average particle diameter of about 1 μm was used for the chemical desiccant 114a of the moisture absorbent 114, and epoxy resin was used for the resin 114b. The content of the chemical desiccant 114a was about 55% by weight, and no curing initiator was added to the resin 114b so that the resin 114b remained liquid in the completed state of the example. In the test, the example was stored in an environment of 60 ° C. and 90% for about 1000 hours.

FIG. 6 is an enlarged plan view of a part of the embodiment of the panel 10, where (a) is a photograph before moisture absorption, and (b) is a photograph after moisture absorption. FIG. 6 is a photograph of the part corresponding to the corner of the planar shape of the example taken from directly above as in FIG.

In the embodiment, unlike the panel 90, the sealing wall 113 is in a relatively uniform transparent state both before moisture absorption (FIG. 6A) and after moisture absorption (FIG. 6B). It can be seen that 101 and the sealing plate 112 are in close contact. That is, in the embodiment, the sealing wall 113 is not peeled off from the substrate 101 and the sealing plate 112 due to moisture absorption.

Hereinafter, the peeling does not occur because the resin 114b of the hygroscopic material 114 is liquid or rubbery. If the panel 10 is configured, the sealing wall 113 is peeled off from the substrate 101 or the sealing plate 112 due to moisture absorption. The fact that it is possible to reduce this will be described.

(2) Relationship between moisture permeation and hygroscopic material transparency As shown in FIG. 6B, in the embodiment of the panel 10 after moisture absorption, the hygroscopic material 114 includes a non-transparent region 114c and a transparent region 114d. It can be seen that exists.

The non-transparent region 114c is a region that is in the same state as the moisture absorbent material 114 before moisture absorption shown in FIG. 6A, and is specifically a clouded region. This is because the chemical desiccant 114a having a refractive index different from that of the resin 114b and having an average particle diameter (several hundreds nm or more) is present in the resin 114b having translucency. This is because the light is internally scattered (ie, Mie scattering) by the chemical desiccant 114a.

The transparent region 114d is a region that exists between the interface with the sealing wall 113 and the non-transparent region 114c along the outer periphery of the hygroscopic material 114. Hereinafter, it will be described that the transparent region 114d is a region where moisture has permeated in the hygroscopic material 114.

The present inventor manufactured a panel 10T having a simpler structure than the panel 10 and conducted a moisture permeation experiment. FIG. 7 is a schematic cross-sectional view showing the panel 10T used in the moisture penetration experiment. As illustrated in FIG. 7, the panel 10 </ b> T includes the same substrate 101 as the panel 10 and a sealing plate 112. Further, in the panel 10T, the organic EL element row is not arranged, and the resin layer 110T using the same material as the resin layer 110 is filled therein. Further, the resin layer 110T is sealed so as to be surrounded by the hygroscopic material 114T and the sealing wall 113T using the same material as the hygroscopic material 114 and the sealing wall 113, respectively.

As described above, the panel 10T has substantially the same configuration as that of the panel 10 except for the organic EL element array, and in particular, the conditions for moisture permeation into the moisture absorbent material 114T from the side are the same. Therefore, also in the panel 10T, as shown in FIG. 6B, the moisture absorbing material 114T after moisture absorption has a non-transparent region 114Tc and a transparent region 114Td.

In the moisture penetration experiment, the panel 10T was stored in an environment of 85 ° C. and 85% or 60 ° C. and 90%, and periodically measured by FT-IR (Fourier transform infrared spectroscopy) and an optical microscope. In FT-IR, the absorption peak intensity around 3650 cm ^−1, which is OH stretching vibration, was measured. In the optical microscope, the boundary between the non-transparent region 114Tc and the transparent region 114Td of the hygroscopic material 114T was measured. Specifically, the position which becomes an intermediate value between the luminance of the non-transparent region 114Tc and the luminance of the transparent region 114Td was measured by an optical microscope.

FIG. 8 is a graph showing the FT-IR measurement results of panel 10T. The measurement results are for an environment of 85 ° C. and 85%. The horizontal axis indicates the distance (μm) in the direction from the outer periphery to the inner periphery (the −X direction in FIG. 7) with the outer periphery (boundary with the sealing wall 113) of the moisture absorbent material 114T as a reference (0 μm). The vertical axis represents the absorption peak intensity of OH stretching vibration. The absorption peak intensity indicated by I ₀ in the graph is the absorption level due to OH contained in the material of the hygroscopic material 114T.

In the graph, as the number of days elapses, the presence of OH exceeding I ₀ starts to be measured from the outer peripheral side, and reaches saturation at a certain level (I ₁₀₀ ). This is due to absorption of the O—H content increased by the penetration of water molecules (H ₂ O). As the number of days elapses, moisture in the outside air permeates the hygroscopic material 114T through the sealing wall 113T, and the chemical It is shown that it is adsorbed by the mechanical desiccant 114a. Moreover, in the area | region which reached the saturated moisture absorption amount of the chemical desiccant 114a, it has shown that a water | moisture content is not adsorb | sucked any more and a water | moisture content penetrate | invades more inside.

FIG. 9 is a graph comparing the measurement results of the optical microscope and FT-IR on panel 10T, where (a) is a graph at 85 ° C. and 85%, and (b) is a graph at 60 ° C. and 90%. It is. The horizontal axis of FIG. 9 shows the storage time (day), and the vertical axis is the distance (μm) in the direction from the outer periphery to the inner periphery with respect to the outer periphery of the hygroscopic material 114T as in the horizontal axis of FIG. Is shown. Note that the FT-IR graph in FIG. 9 shows the measurement position at which the absorption peak intensity (I _{50 in} FIG. 8) is intermediate between I ₀ and I ₁₀₀ .

As shown in FIGS. 9A and 9B, the measurement position of the boundary of the transparent region 114Td by the optical microscope based on the outer periphery of the hygroscopic material 114T and the moisture penetration distance measured by FT-IR are 85. It is almost the same in both environments of 85 ° C. and 90% of 60 ° C. That is, the moisture permeation distance and the distance to the boundary of the transparent region 114Td are substantially equal with reference to the outer periphery of the hygroscopic material 114T. Therefore, it can be said that the transparent region 114Td is a region into which moisture has penetrated in the hygroscopic material 114T. Here, since the hygroscopic material 114 of the panel 10 uses the same material as the hygroscopic material 114T of the panel 10T, the transparent region 114d in the hygroscopic material 114 of the embodiment of the panel 10 also includes moisture in the hygroscopic material 114. It can be seen that this is a permeated region.

(3) State of chemical desiccant in the transparent region Next, the state of the chemical desiccant 114a in the transparent region 114d will be described. Note that the hygroscopic material 114 before moisture absorption is in a cloudy state due to light Mie scattering by the chemical desiccant 114a.

FIG. 10 is a graph showing the correlation between the light transmittance of the hygroscopic material and the average particle diameter of the desiccant. Specifically, it is a result of simulation using the average particle diameter as a parameter for light transmittance when particles having different refractive indexes are dispersed in a resin. The scattering in the particles was Mie scattering when the refractive index of the particles was larger than that of the resin, and the wavelength of light used for the simulation was 590 nm. In the simulation, only the average particle diameter is changed for the desiccant in the hygroscopic material, and the number of particles is constant.

FIG. 10 shows that in the resin containing particles that cause Mie scattering of light, the average particle diameter of the particles is proportional to the light scattering loss (= 1−light transmittance). Here, as described above, in the hygroscopic material 114, the non-transparent region 114c becomes the transparent region 114d due to moisture absorption. In other words, it can be inferred that in the hygroscopic material 114, the average particle diameter of the chemical desiccant 114a in the transparent region 114d is reduced by moisture absorption. In particular, from the graph of FIG. 10, it is considered that the average particle diameter of the chemical desiccant 114a is 500 nm or less.

In addition, the average particle diameter of a general chemical desiccant 114a is several μm or more, and even a small one has almost 500 nm or less. This is because, in a chemical desiccant, if the average particle size is 500 nm or less, the activity becomes too high due to an increase in the specific surface area, and the moisture absorption reaches saturation just by touching the outside air for a short time, making it impractical. It is.

Further, the transparent region 114d is a region where moisture penetrates. Usually, the volume of the chemical desiccant 114a particles that have adsorbed moisture expands. This is because the chemical desiccant 114a becomes a hydroxide or a hydrate due to adsorption of lighter moisture than the chemical desiccant 114a, and the density decreases.

Therefore, if the chemical desiccant 114a that has adsorbed moisture is in a powder state, the average particle diameter of the particles should be at least 500 nm due to the volume expansion, and the region of the moisture-absorbing material 114 into which moisture has penetrated There is no transparency. On the other hand, the transparent region 114d in which moisture penetrates is transparent.

From this, it is considered that in the hygroscopic material 114, the chemical desiccant 114a in the transparent region 114d is not in a powder state but dissolved in a liquid or rubber-like resin 114b. More specifically, it is assumed that the chemical desiccant 114a that has adsorbed moisture is ionized in the resin 114b to be in an ionic state. For example, in the embodiment, it is considered that calcium oxide as the chemical desiccant 114a adsorbs moisture, so that it is ionized into calcium ions and hydroxide ions and dissolved in the liquid epoxy resin.

At this time, the ionized chemical desiccant 114a is much smaller than the powdered chemical desiccant 114a and can enter the gaps between the molecules of the liquid or rubber-like resin 114b. Therefore, in the hygroscopic material 114 of the panel 10, the volume does not increase even if the amount of substance increases due to the adsorbed moisture. Therefore, in the panel 10, it can reduce that the sealing wall 113 peels from the board | substrate 101 or the sealing board 112 by moisture absorption.

As shown in FIG. 12, in the panel 90 using the moisture absorbent material 914 that is a cured (glassy) resin, the moisture absorbent material 914 after moisture absorption is not transparent, and the resin of the chemical desiccant as described above. No dissolution in it occurred. This is because the chemical desiccant must be more stable in the ionized state than in the powder state in order for the chemical desiccant to be dissolved (ionized), so that the molecules in the resin can surround the ionized ions. This is thought to be because it must be able to move and deform to a certain extent.

From the above, in the hygroscopic material 114, it is considered that the resin 114b is liquid or rubbery, whereby the molecules of the resin 114b are deformed, and the chemical desiccant 114a after moisture absorption is dissolved in the resin 114b.

That is, the panel 10 can dissolve the chemical desiccant 114a and reduce the peeling of the sealing wall 113 because the hygroscopic material 114 is a liquid or rubber-like resin 114b.

4). Others In the panel 10, the chemical desiccant 114a preferably has an average particle size of 500 nm or more. As described above, when the average particle size is 500 nm or more, an excessive improvement in activity due to an increase in specific surface area can be suppressed. Therefore, in this case, since the moisture absorption amount of the chemical desiccant 114a being manufactured can be reduced without excessive humidity control, the function of the moisture absorbent material 114 at the time when the panel 10 is completed can be secured. In addition, the average particle diameter of the chemical desiccant 114a can be measured by, for example, a dynamic light scattering method. Specifically, an appropriate amount is sampled from the powder of the chemical desiccant 114a before being added to the resin 114b, the particle size distribution is measured by a dynamic light scattering method, and the median value (d50) is calculated from the particle size distribution. Can be regarded as the average particle size of the entire chemical desiccant 114a. For example, the average particle diameter of the chemical desiccant 114a contained in the resin 114b can be directly measured by using a scanning electron microscope (SEM), a transmission electron microscope (TEM), or the like.

Moreover, in the panel 10, it is preferable that the resin 114b is composed of molecules having polarity. That is, it is preferable that the molecules constituting the resin 114b include an element such as oxygen or nitrogen with high electronegativity. Specifically, the molecule constituting the resin 114b preferably has a polar group such as a hydroxy group, an amino group, a carbonyl group, a carboxyl group, an oxo group, or a nitro group. At this time, when the hygroscopic chemical desiccant 114a is ionized into the resin 114b, hydrogen bonds between the constituent molecules of the ionized chemical desiccant 114a and the constituent molecules of the resin 114b are strengthened, and the dissolved state is further stabilized. . That is, in this case, the chemical desiccant 114a is more easily dissolved in the resin 114b.

The hygroscopic material 114 is preferably in close contact with surrounding members (the thin film sealing layer 109, the resin layer 110, the color filter layer 111, the sealing plate 112, the sealing wall 113, etc.). The hygroscopic material 114 is a liquid or rubber-like resin and is in a state where it can flow or deform. However, like the panel 10, the hygroscopic material 114 becomes a glass state by solid solid sealing layer 109 and curing. When sandwiched between the resin layer 110 and the sealing wall 113, the shape of the hygroscopic material 114 is stabilized. Furthermore, when the hygroscopic material 114 is in close contact with the sealing plate 112, the gap between the sealing plate 112 and the hygroscopic material 114 can be reduced, which is advantageous for thinning. Further, when the outer periphery of the hygroscopic material 114 is in close contact with the sealing wall 113 and the inner periphery of the hygroscopic material 114 is in close contact with the thin film sealing layer 109 and the resin layer 110, the gap in the frame region of the panel 10 is reduced, and the sandwiched frame It is advantageous to make. In particular, the hygroscopic material 114 has suppressed volume expansion due to moisture absorption, and even if the hygroscopic material 114 is brought into close contact with surrounding members without providing a gap, the panel 10 is not easily deformed or broken by the internal pressure. That is, the panel 10 can make the moisture absorbing material 114 in closer contact with the surrounding members than a general organic EL display panel, and is advantageous in reducing the thickness and the frame. In addition, the moisture passage around the hygroscopic material 114 is closed due to close contact, and the penetration of moisture into the organic EL element array 100A can be further suppressed.

Further, the organic EL display panel according to one aspect of the present invention is not limited to the panel 10 according to the present embodiment except for essential characteristic components.

In the panel 10, the hygroscopic material 114 is disposed on the thin film sealing layer 109. However, the present invention is not limited to this. For example, the moisture absorbing material 114 may be disposed on the substrate 101 or the passivation layer 103. May be.

Further, in the panel 10, the sealing wall 113 is disposed over the passivation layer 103 and the thin film sealing layer 109. However, the present invention is not limited to this. For example, the sealing wall 113 is disposed only on one of the layers. Alternatively, all or a part of the substrate 101 may be disposed.

Further, in the panel 10, the peripheral edge 100E of the organic EL element array 100A, the substrate 101, the sealing plate 112, the sealing wall 113, and the hygroscopic material 114 are rectangular, but the present invention is not limited thereto. A part of the shape may be a polygonal shape, a circular shape, an elliptical shape, or the like.

In the panel 10, the functional layer 106 is divided for each organic EL element 100. However, the functional layer 106 is not limited thereto, and is formed on the entire surface of the organic EL element row 100 </ b> A like the common electrode 107. It may be a single layer. Further, for example, the functional layer 106 may be a layer that continues only in a part of the organic EL element row 100A (such as the organic EL element 100 on the same straight line). In addition, when the functional layer 106 includes a plurality of layers, a layer divided for each organic EL element 100 and a continuous layer in the plurality of organic EL elements 100 may be combined.

Further, the panel 10 has a forward structure in which the pixel electrode 105 of the organic EL element 100 is an anode and the common electrode 107 is a cathode. For example, the panel 10 has an inverted structure in which the pixel electrode 105 is a cathode and the common electrode 107 is an anode. May be.

In addition, the panel 10 employs a top emission type and an active matrix system, but is not limited thereto, and for example, a bottom emission type or a passive matrix system may be employed. In the case of adopting the bottom emission type, the resin layer 110 may be replaced with the hygroscopic material 114.

Moreover, what was described as a material of each part in the panel 10 is an example, and is not limited thereto, and a known material or a material having equivalent properties may be used.

The organic EL display panel according to the present invention can be widely used in devices such as televisions, personal computers, portable terminals, business displays such as electronic signboards and large screens, and other various electronic devices having display functions. it can.

DESCRIPTION OF SYMBOLS 10, 90 Organic EL display panel 10T panel 100 Organic EL element 100A Organic EL element row | line | column 100E Perimeter 101 Substrate 109 Thin film sealing layer 110 Resin layer 112 Sealing plate 113, 113T Sealing wall 114, 114T, 914 Hygroscopic material 114a, 114Ta Chemical desiccant 114b, 114Tb resin

Claims (11)

A substrate,
An organic EL element array composed of a plurality of organic EL elements arranged above the substrate;
A sealing plate facing the substrate above the organic EL element array;
A sealing wall for sealing the organic EL element row by surrounding a periphery of the organic EL element row between the substrate and the sealing plate;
A hygroscopic material surrounding a periphery of the organic EL element row between the organic EL element row and the sealing wall;
With
The hygroscopic material is a liquid or rubber-like resin containing a chemical desiccant,
Organic EL display panel. The hygroscopic material has the property of becoming transparent by moisture absorption,
The organic EL display panel according to claim 1. The chemical desiccant is ionized in the resin by moisture absorption;
The organic EL display panel according to claim 1. The chemical desiccant is a powder of an oxide of an alkali metal element or an alkaline earth metal element;
The organic electroluminescence display panel in any one of Claims 1-3. The chemical desiccant has an average particle size of 500 nm or more;
The organic EL display panel according to claim 4. The viscosity of the resin is 10 Pa · s or more and 10,000 Pa · s or less,
The organic EL display panel according to any one of claims 1 to 5. The resin is a non-curable resin;
The organic EL display panel according to claim 1. The resin is composed of polar molecules;
The organic EL display panel according to claim 1. The content of the chemical desiccant in the resin is 10 wt% or more and 60 wt% or less.
The organic EL display panel according to claim 1. The hygroscopic material is in intimate contact with the sealing plate;
The organic EL display panel according to claim 1. Furthermore, a thin film sealing layer made of an inorganic material and covering the upper and peripheral edges of the organic EL element array;
A resin layer made of a glass-like resin and disposed between the thin film sealing layer and the sealing plate;
With
The outer periphery of the hygroscopic material is in intimate contact with the sealing wall;
The inner periphery of the moisture absorbent material is in intimate contact with the thin film sealing layer and the resin layer;
The organic EL display panel according to claim 1.

Images