JP2000173766A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device that can prevent display degradation due to moisture and can be designed, without being restricted on the size and capability of TFTs for driving a luminescent layer in relation to the display device, wherein a luminescent layer emitting light in itself like an organic EL layer is enclosed inside. SOLUTION: A first board 1 is bonded to a cap 10, and a powdery desiccant is mixed in a seal 11 for sealing a display region. Moisture permeation from board surfaces nipping the display region can nearly be neglected, and since the moisture permeating the seal 11 is adsorbed by the desiccant, a luminescent layer can be prevented from being degraded by the moisture. The display region is protected from the moisture by covering the display region with a resin sealing layer formed of a desiccant-mixed resin. The moisture is surely adsorbed by forming a slot on the board and by arranging the desiccant in it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescence (hereinafter, referred to as "electroluminescence") on a substrate.
Called "EL". The present invention relates to a display device having an element, particularly, an organic EL layer and a thin film transistor (Thin Film Transi).
stor: Hereinafter, referred to as “TFT”. The present invention relates to a sealing structure of an active matrix type organic EL display device provided with ()).

[0002]

2. Description of the Related Art A display device using an organic EL is a self-luminous element which emits light by flowing an electric current.
It consumes less power than T and does not have the problem of viewing angle unlike LCD. Therefore, the organic EL display device is C
It is receiving attention as a display device that replaces RT and LCD.
FIG. 8A is a plan view showing a conventional organic EL display device, and FIG. 8B is a sectional view taken along the line AA ′. A plurality of selection drive circuits 2 are arranged on a transparent substrate 1 for each pixel. A pixel electrode 4 is connected to each of the selection drive circuits 2, and an organic EL layer 5 and a counter electrode 6 are arranged so as to cover them. A driver circuit 7a for controlling the selection drive circuit 2 and applying a predetermined voltage to the pixel electrode 4 is provided around a display area including the selection drive circuit 2, the pixel electrode 4, the organic EL layer 5, and the counter electrode 6. 7b is arranged. The driver circuit 7 is connected to a terminal 9 by a wiring 8. A cap 10 made of a metal such as aluminum is arranged so as to cover those structures, and is fixed to the transparent substrate 1 using a seal 51. Space 1 between cap 10 and transparent substrate 1
2 is filled with dry nitrogen, and a desiccant sheet 13 is provided on the inner surface of the cap 10.

The selection drive circuit 2 has a plurality of semiconductor elements such as thin film transistors (TFTs). The first TFT switches between conduction and non-conduction according to the output of the driver circuit 7a. A voltage corresponding to the output of the driver circuit 7b is applied to the pixel electrode 4 in which the first TFT of the selection drive circuit 2 is turned on by the output of the driver circuit 7a via the second TFT. Current flows during The light emitting layer 5 is configured to emit light when a current flows therein, and emits light at an intensity corresponding to the amount of current flowing between the pixel electrode 4 and the counter electrode 6.
The generated light passes through the transparent substrate 1 downward in the cross-sectional view and is visually recognized.

The organic EL layer 5 is formed for each pixel so as to emit a different color for each pixel.

FIG. 9 is a sectional view showing one pixel in more detail. A gate electrode 41 made of a refractory metal such as Cr or Mo is arranged on an insulating substrate 1 made of quartz glass, non-alkali glass or the like. On the gate electrode 41, a gate insulating film 42 made of SiN / SiO2 and an active layer 43 made of a polysilicon film are sequentially stacked. The active layer 43 is provided with a channel 43c above the gate electrode 41, and a source 43s and a drain 43d in a high concentration region on both sides of the channel 43c. The source 43s and the drain 43d are connected to the channel 43
A so-called LDD structure having a low-concentration region and a high-concentration region on both sides of the gate electrode 41 by performing ion doping using the stopper insulating film 44 on the mask c as a mask and further performing ion doping while covering both sides of the gate electrode 41 with a resist. It is. The selection drive circuit 2 is a general term for the gate electrode 41, the gate insulating film 42, and the active layer 43.

Then, an SiO 2 film, a SiN film, and the like are formed on the entire surface of the gate insulating film 42, the active layer 43, and the stopper insulating film 44.
An interlayer insulating film 45 is formed by laminating a film and a SiO2 film in this order, and a contact hole provided corresponding to the drain 43d is filled with a metal such as Al and connected to the drive power supply line 46. Further, a flattening insulating film 47 made of, for example, an organic resin and flattening the surface is formed on the entire surface. Then, a contact hole is formed at a position corresponding to the source 43s of the flattening insulating film 47, and an ITO (Indium Thin Oxid) contacting the source 13s through the contact hole.
e) A transparent electrode 3 composed of the above is disposed.

The organic EL layer 5 is made of MTDATA (4,4-bis
(3-methylphenylphenylamino) biphenyl)
Hole transport layer 5a, TPD (4,4,4-tris (3-methylphe
a second hole transport layer 5b composed of (nylphenylamino) triphenylanine), a light emitting layer 5c composed of Bebq2 (10-benzo [h] quinolinol-beryllium complex) containing a quinacridone derivative, and a light emitting element composed of an electron transport layer 5d composed of Bebq2. Layer. The above configuration is described in, for example, Japanese Patent Application No. 11-22183 or Japanese Patent Application No. 11-2.
2184 and the like.

In the organic EL layer 5, holes injected from the anode and electrons injected from the cathode are recombined inside the organic EL layer 5 to excite organic molecules forming the organic EL layer 5. Excitons are generated. Light is emitted from the organic EL layer 5 in the process of extinguishing the excitons, and the light is emitted from the transparent anode to the outside through the transparent insulating substrate 1 to emit light.

[0009] The TFT and the organic EL thus formed are laminated.
Layer 5 is covered by a cap 10 made of a metal such as aluminum. The cap 10 is adhered to the periphery of the insulating substrate 1 by a seal 51 made of a sealant such as epoxy. In the organic EL layer, for example, when a defect such as a pinhole is generated in the counter electrode 6, the counter electrode 6 is oxidized by moisture entering therethrough,
A dark spot occurs due to separation between the L layer 5 and the counter electrode 5, and the display quality is significantly deteriorated. The cap 10 has a role of protecting the display area and the driver circuit 7 from physical impact and also preventing the invasion of moisture. Therefore, it has a dish-like shape so as to cover the display area. In addition, cap 1
A space 12 in the space 0 is filled with an inert gas such as dry nitrogen or helium, and a desiccant sheet 13 is further provided.
Further, a step may be further provided at the installation location for disposing the desiccant sheet 13. Such a configuration is disclosed, for example, in JP-A-9-148066.

[0010]

However, in the conventional sealing structure, moisture accumulates, for example, by remaining in the nitrogen filled in the space 12. On the other hand, since the desiccant sheet 13 is disposed on the cap 10,
Water may adhere to the organic EL layer without being adsorbed by the desiccant sheet 13.

The desiccant sheet 13 is formed by wrapping a desiccant powder in a porous film and has a thickness of about 1 mm. This is very thick compared to the thickness of the display area of about several μm, and the space 12 is formed due to the structure of being fixed to the inner surface of the cap 10.
There is a limit in reducing the thickness of the entire display device.

In the structure of the conventional display device described above, light is emitted from the organic EL layer 5 on the side of the insulating substrate 1 on which the TFT is provided, so that the emitted light is blocked by the TFT. There is a limitation in increasing the aperture ratio of the display pixel 1.

Further, in the case of the conventional structure, there is a restriction that the TFT must be made as small as possible so as not to block the emitted light, so that the size of the TFT and the capability of the TFT are also limited.

Therefore, the present invention provides a more reliable organic EL layer 5.
An object of the present invention is to provide an organic EL display device having a sealing structure capable of preventing moisture from adhering to the device, and capable of reducing the overall thickness. The degree of freedom in determining the size and driving ability of the TFT for driving the TFT can be increased, and the process can be simplified by providing the color elements on another substrate facing the substrate on which the TFT is formed. It is an object to provide an EL display device.

[0015]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a display device in which a display area which emits light by applying a voltage between a pair of substrates is sealed between the pair of substrates. This is a display device on which a resin mixed with an agent is arranged.

The pair of substrates are adhered to each other by a seal formed around the display area, and a desiccant is mixed in the seal.

Furthermore, around at least one of the substrates,
It has a concave-shaped groove, and a desiccant is sealed in this groove.

Further, the groove is covered with a seal for bonding the pair of substrates to each other.

Further, a color element is provided between a second substrate of the pair of substrates facing the first substrate on which the display region is formed, and the display region, and the second substrate emits visible light. It is a transparent substrate that transmits light.

Further, between a display area and a second substrate of the pair of substrates facing the first substrate on which the display area is formed, light of a predetermined color is converted into light of a different color. It has a fluorescence conversion layer, between the fluorescence conversion layer and the display area,
A spacer comprising a desiccant is provided.

The resin mixed with the drying agent is formed so as to cover the display area.

Further, a resin formed so as to cover the display region is filled between the display region and a second substrate of the pair of substrates facing the first substrate having the display region. I have.

Also, a transparent first substrate, a plurality of selection driving circuits disposed on the first substrate, a plurality of pixel electrodes respectively connected to the selection driving circuit, and a plurality of pixel electrodes are formed to cover the plurality of pixel electrodes. In the electroluminescent display device having the electroluminescent layer and a plurality of pixel electrodes and a counter electrode facing each other with the electroluminescent layer interposed therebetween, the selection drive circuit, the pixel electrode, the entire display region including the electroluminescent layer and the counter electrode are removed. A display device having a resin sealing layer formed so as to cover and mixed with a desiccant, and a second substrate disposed outside the resin sealing layer and opposed to the first substrate.

Further, the desiccant described above is a substance having a chemical adsorption property, and is a powder having a particle size of 20 μm or less.
10 wt% or more and 50 wt% or less are mixed in the resin sealing layer.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <First Embodiment> FIG.
1 is a plan view of an organic EL display device according to a first embodiment of the present invention, and FIG. 1B is a cross-sectional view along AA ′. The same reference numerals are given to the same structures as those in the related art, and the detailed description will be omitted. A selection drive circuit 2 is arranged for each pixel on a transparent substrate 1, a pixel electrode 4 is arranged via a planarization insulating film 3, and an organic EL layer 5 and a counter electrode 6 are arranged so as to cover them. The selection drive circuit 2, the planarization insulating film 3, the pixel electrode 4, the organic EL layer 5, and the counter electrode 6 are collectively referred to as a display area. Driver circuits 7a and 7b for controlling the selection drive circuit 2 and applying a predetermined voltage to the pixel electrode 4 are arranged around the display area. The driver circuit 7 is connected to a terminal 9 by a wiring 8. The display area is covered by a metal cap 10 which is a second substrate arranged opposite to the substrate 1, and a desiccant sheet 13 is arranged inside the cap 10. The above structure is the same as that of the conventional display device.

A feature of this embodiment is that a desiccant powder is mixed in a seal 11 for bonding the cap 10 and the transparent substrate 1.

The seal is formed of a synthetic resin such as acrylic, and the synthetic resin transmits a small amount of water. The amount of water permeation varies depending on the type of resin, for example, XNR5 made by Nagase Chiba
493T is a resin with relatively low moisture permeability,
Permeates 7 g / m 2 of water per day in an environment of 90 ° C. and 90% humidity. (Catalog value) If such permeated water adheres to the display area before being absorbed by the desiccant sheet 13, the organic EL layer 5 may be deteriorated. However, in this embodiment, since the desiccant powder is mixed in the seal 11, almost no moisture permeates through the seal.

The seal 11 is preferably made of, for example, an epoxy resin, and is of a type that is cured by mixing two liquids or irradiating ultraviolet rays. The type cured by heating is not suitable because the organic EL layer 5 may be deteriorated by heating. The viscosity of the resin before curing is 1
Use the one of about 00000 cps to 300,000 cps.
In order to uniformly mix the desiccant, it is desirable to use a resin having a viscosity as low as possible within a range where the resin does not flow before curing.

If the desiccant is mixed before the seal 11 is cured, and is sufficiently kneaded and then the resin is cured, the desiccant can be uniformly mixed into the seal 11. As the desiccant, a substance having a chemical adsorption property is used. Examples of the chemisorbing desiccant include oxides of alkaline earth metals such as calcium oxide and barium oxide, halides of alkaline earth metals such as calcium chloride, and phosphorus pentoxide. Physically adsorptive desiccants such as silica gel are not suitable because they release adsorbed moisture at high temperatures. <Second Embodiment> FIG. 2A is a plan view of an organic EL display device according to a first embodiment of the present invention, and FIG. 2B is a sectional view taken along the line AA ′. The same structures as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted.

A feature of the present embodiment is that a groove is provided below the seal 11 of the transparent insulating substrate 1, and a desiccant 14 is disposed in the groove.

As described above, it is necessary to use a resin having a relatively high viscosity to prevent the seal 11 from flowing before curing. Therefore, it is difficult to mix the desiccant uniformly. Further, in order not to lose the viscosity of the resin before curing, there is a limit to the amount of the desiccant that can be mixed.
If the width of the seal 11 is small, the amount of the desiccant to be mixed in is small, and there is a possibility that all the permeated moisture cannot be adsorbed. In the present embodiment, a groove is provided in the transparent insulating substrate 1 and the desiccant 14 is disposed therein. The desiccant 14
After a desiccant is mixed into a resin having a low viscosity, it may be poured into the groove and cured, and then the seal 11 may be formed. The desiccant 14 in the groove may be a granular desiccant having a large particle size. May be fixed with a resin having a low viscosity, or the desiccant 14 may be formed according to the shape of the groove, and may be fitted. In any case, a sufficiently large amount of the desiccant 14 can be arranged in the groove in comparison with the amount of moisture transmitted through the seal 11. Most of the water that has entered the seal 11 is absorbed by the desiccant mixed with the resin in the groove, and therefore hardly enters the inside of the display device.

If the desiccant 14 is exposed to the outside, it absorbs abundant moisture contained in the outside air, and immediately loses its adsorbing ability. Therefore, the desiccant 14 is provided below the seal 11 so as not to be exposed to the outside.
It is good to arrange it covered with. Of course, it is more effective if a desiccant is mixed in the seal 11 as well.

In this embodiment and in the fourth and sixth embodiments described below, the groove is formed only in the first substrate 1, but the opposing substrate (the cap 10 in this embodiment) is also formed in the first substrate 1. It is more effective to form a groove and place a desiccant there as well. <Third Embodiment> FIG. 3 shows a third embodiment, in which a color filter 21 is provided as a color element and a first substrate 1 'is provided.
FIG. 2 is a cross-sectional view of an organic EL display device having a second substrate 22 and a second substrate 22. The same structures as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted. In the present embodiment, the first
Unlike the embodiment, the light emitted from the organic EL layer 5 passes through the transparent counter electrode 25 and emits light upward in the drawing. The organic EL layer 5 emits white light from the entire surface, and
As a result, light of each color is obtained, and color display is performed.

The pixel electrode 23 has a lower layer 23a made of an opaque conductive material, for example, molybdenum (Mo) formed on the surface including the planarizing insulating film 3 and the contact holes provided in the planarizing insulating film 3, and formed thereon. It is a stacked structure with the upper layer 23b made of ITO. Mo upper layer 23a and I
The lower layer 23b of the TO may have the same shape. The lower layer 23a is provided to reflect light generated in the organic EL layer 5 and efficiently emit light. The opaque conductive material is not limited to Mo but may be a metal such as aluminum (Al) or silver (Ag). Further, the upper layer 23b of ITO is provided thereon in order to have a high work function and to efficiently emit light from the organic EL layer 5.

An alkali metal such as lithium and sodium, an alkaline earth metal such as potassium, calcium and magnesium is provided between the counter electrode and the organic EL layer 5.
Alternatively, the buffer layer 24 made of a material having a high work function such as a fluorine compound of these metals is formed.

The second substrate 22 is a transparent substrate made of glass or synthetic resin. Since the present embodiment emits light from above, the first substrate 1 'may be transparent or opaque.

The light emitted from the organic EL layer 5 is emitted from the transparent counter electrode 25 to the outside (upward on the paper indicated by an arrow in the figure). That is, the insulating substrate 22 having no TFT is used.
Emit light to the side. The counter electrode 25 is formed so as to face the plurality of selection drive circuits 2 and the pixel electrodes 23, and is formed over the entire display area as shown in FIG.

The color filter 21 as a color element formed on the transparent and insulating second substrate 22 will be described below. A color filter 21 is provided as a color element on the display panel of the above-described organic EL display device. As shown in FIG.
A color filter 21 including red (R), green (G), and blue (B) is provided on a second substrate 22 such as a transparent film or a glass substrate on the side of the counter electrode 25.

The color filter 21 is provided on the second substrate 22
Of the organic EL layer 5 on the opposite electrode 25 side. Then, the second substrate 22 and the first substrate 1 'are adhered and fixed around their periphery by a seal 26 having an adhesive function. Note that the color filter 21 is formed by the organic EL layer 5 and the T
Each color is provided corresponding to each display pixel 1 made of FT. A black matrix (BM) 27 that blocks light between the colors may be provided. The emitted light from the organic EL layer 5 passes through the color filter 21 and emits each color in the direction of the arrow in the figure.

Here, the light emitting material of the organic EL layer 5 will be described. The light emitting material of the organic EL layer 5 is selected according to the color elements provided on the organic EL layer 5. That is, when a color filter including R, G, and B is used as in the case of the present embodiment, white light is used as light emitted from the organic EL layer 5. In order to emit white light, as a material of the organic EL layer 5, a ZnBTZ complex is used, or TPD (aromatic diamine) / p-EtTAZ of a laminate is used.
It can be realized by using (1,2,4-triazole derivative) / Alq (however, “Alq” means doping partially with Neil Red which is a red light-emitting dye).

Here, the sealant for bonding the transparent insulating substrate 22 and the insulating substrate 2 will be described. The seal 26 for bonding the two substrates 1 'and 22 is made of an epoxy-based resin, into which a desiccant such as calcium oxide, phosphorus pentoxide, and calcium chloride is mixed. By mixing a desiccant into the sealant, both the substrates 1 ′ and 22 and the seal 2
6 can absorb the moisture in the space formed by the drying agent, so that the display deterioration due to the adverse effect of the moisture on each layer made of the organic material can be prevented. The composition of the seal 26 is basically the same as that of the seal 11 of the first embodiment. In the case of a mode in which light is emitted from above as in the present embodiment, the desiccant sheet 13 cannot be disposed, so that the desiccant of the seal 26 is extremely important.

As described above, according to the organic EL display device of the present invention, the second substrate 22 provided with the color filter 21
Since the light can be emitted from the side, the light is not blocked by the TFT, so that the aperture ratio of each display pixel 1 can be designed to the maximum and the organic EL can be used.
It is possible to increase the degree of freedom for determining the size and the driving ability of the TFT for driving the layer 5.

Since the aperture ratio of the display pixels can be improved, it is not necessary to increase the current density in order to obtain a bright display, and the life of the organic EL layer 5 can be extended.

In the case of the present embodiment, only one kind of white light-emitting material may be used as the light-emitting material used as the organic EL layer 5. Since only the color filter is arranged and the color filter forming surface and the opposing electrode 25 side of the organic EL layer 5 are adhered to each other, three types of organic light are contained in the organic EL layer 5 in order to emit three primary colors as in the related art. The process can be greatly simplified as compared with the case where an EL material is formed.

Furthermore, since the emitted light is emitted from the color filter provided on the counter electrode side as the color of the display pixel, the area of the emitted light is larger than that emitted from the TFT substrate side as in the conventional case, and the area is bright and clear. Color display can be obtained. <Fourth Embodiment> FIG. 4 is a sectional view of an organic EL display device according to a fourth embodiment of the present invention. The same structures as those in the third embodiment are denoted by the same reference numerals, and detailed description is omitted.

A feature of this embodiment is that a groove is provided below the seal 11 of the transparent insulating substrate 1 as in the second embodiment, and a desiccant 14 is disposed in the groove. It is. The desiccant 1 in the groove as in the second embodiment.
4 mixes a sufficient amount of a desiccant in a resin with high fluidity,
Since it is formed by pouring, the efficiency of adsorbing moisture is high. <Fifth Embodiment> FIG. 5 is a cross-sectional view of a display device when a fluorescence conversion layer 31 is used as a color element. As shown in the drawing, the difference from the third embodiment is that a fluorescent conversion layer 31 is formed on a transparent insulating substrate 22 instead of the color filter 21, and the material of the organic EL layer 5 is, for example, a blue light emitting material. The difference is that a spacer 32 made of a desiccant is provided between the fluorescence conversion layer 31 and the counter electrode 25. The fluorescence conversion layer 31 is a layer that receives, for example, blue light and emits light of a predetermined color according to its intensity. Therefore, light can be emitted in a predetermined color without using a color filter.
Since the fluorescence conversion layer 31 emits light by itself, the light quantity does not attenuate unlike a color filter.

An organic material is deposited on a transparent insulating substrate 22 such as a glass substrate by a vapor deposition method to form a fluorescence conversion layer 31 corresponding to the pixel electrode 23. And the transparent insulating substrate 2
2 and the insulating substrate 2 are adhered by a seal 26 having an adhesive property such that the transparent insulating substrate 22 on which the fluorescence conversion layer 31 is formed has the fluorescence conversion layer 31 on the side of the counter electrode 25.

Then, a spacer 32 is arranged between the fluorescence conversion layer 31 and the counter electrode 25. Spacer 3
2, the distance between the fluorescence conversion layer 31 and the counter electrode 25 is maintained. The diameter of the spacer 32 may be such that the spacing can be maintained, for example, about several μm to several hundred μm.

The greatest feature of the present embodiment is that the spacer 32 is formed of a desiccant such as calcium oxide, phosphorus pentoxide, calcium chloride and the like. The spacer 32 can absorb moisture in a region formed by the insulating substrate 2, the transparent insulating substrate 22, and the fluorescence conversion layer 31. The space around the spacer 32 may be a space filled with nitrogen, helium, or the like, or may be filled with a resin or the like.

The case where the organic EL layer 5 of the organic EL layer 5 is made of a material that emits blue light as the fluorescence conversion layer 31 will be described below. The fluorescence conversion layer 31 has a function of converting the color of the irradiated colored light into another color. Therefore, when trying to obtain R, G, and B of three primary colors from a color display device using a blue light emitting material for the organic EL layer 5, the fluorescent conversion layer 31 converts blue into red or green. It must be formed using materials.

When converting blue light emitted from the organic EL layer 5 to red light, the organic EL layer 5 is formed by using 4-dicyanomethylene-2-methyl-6- (p-dimethylaminostillin) -4H-. It is formed using pyran (DCM) or the like. By doing so, red light can be emitted from the display pixels.

Next, as a material for converting blue light emitted from the organic EL layer 5 into green light, 2,3,5,6-1H,
It is formed using 4H-tetrahydro-8-trifluoromethylquinolizino (9,9a, 1-gh) coumarin or the like.
Green can be emitted from the display pixel.

Further, a display pixel which emits blue light from the organic EL layer 5 may be provided with a blue conversion layer in order to increase the color purity of blue. In that case, for example, oxadiazole (OXD), azomethine-zinc complex (AZM), Al-
A blue light emitting material comprising a quinoline mixed ligand complex + perylene is formed.

In the case of the present embodiment, only one kind of blue light-emitting material may be used as the light-emitting material used as the organic EL layer 5, and one layer of three kinds of fluorescent conversion materials is formed on the transparent substrate 21. Therefore, the process can be greatly simplified as compared with the case where three kinds of materials of the organic EL layer 5 are formed in the organic EL layer 5 to emit three primary colors as in the related art.

In this embodiment, the organic EL
Although the case where the light emitted from the layer 5 is blue has been described,
The present invention is not limited to this.
The light from can be red or green. At this time, when the organic EL layer 5 that emits red light is used, a fluorescent conversion layer 31 made of a material that converts red into blue and green is provided, and the organic EL layer 5 that emits green light is used. Is provided with a fluorescence conversion layer 31 made of a material for converting green into red and blue.

As described above, light can be emitted from the transparent insulating substrate 21 provided with the fluorescence conversion layer 31.
Since the light is not blocked by the TFT, the aperture ratio of the display pixel can be designed to the maximum, and the degree of freedom in determining the size and the driving ability of the TFT can be increased.

Further, since the aperture ratio of the display pixels can be improved, it is not necessary to increase the current density in order to obtain a bright display, and the life of the organic EL layer 5 can be extended.

Further, also in this embodiment, since the emitted light is emitted from the side of the fluorescence conversion layer 31 provided on the anode, the area for emitting the color becomes larger and brighter than that emitted from the TFT substrate side as in the conventional case. A clear color display can be obtained.

Also, as in the third embodiment, the desiccant in the resin is extremely important since the desiccant sheet 13 cannot be disposed since the light is emitted from the drawing and the desiccant sheet 13 cannot be disposed. <Sixth Embodiment> FIG. 6 is a partial sectional view of an organic EL display device according to a sixth embodiment of the present invention.

This embodiment is different from the fifth embodiment in that a groove is provided around the insulating substrate 1 'and a desiccant 14 is provided.

The groove 26 is used to connect the insulating substrate 2 to the groove 25.
The substrate 2 is formed by etching using a mask having an opening only in the region.

After the TFT is formed on the insulating substrate 2, a desiccant is sealed in the groove 26 before the transparent insulating substrate 22 provided with the fluorescence conversion layer 31 is bonded with a sealant. After the sealing, the two substrates 2 and 22 are adhered by the seal 26 to complete the organic EL display device.

As a desiccant to be encapsulated, calcium oxide, phosphorus pentoxide, calcium chloride and the like can be used.

As described above, the moisture adsorbed on the seal 26 can be captured by the desiccant 14 sealed in the groove, and the transparent insulating substrate 1 ′ and the counter electrode 25 can be separated by the spacer 32 as the desiccant. In this case, it is possible to prevent the deterioration of the organic material due to the water and the display deterioration accompanying the water. <Seventh Embodiment> FIG. 7A is a plan view of an organic EL display device according to a seventh embodiment of the present invention, and FIG. 7B is a sectional view taken along the line AA ′. The same reference numerals are given to the same structures as those in the related art, and the detailed description will be omitted.

The present embodiment is characterized in that the resin sealing layer 33 is formed so as to cover the entire display area. The second substrate 22 is further disposed on the resin sealing layer 33.

The thickness of the resin sealing layer 33, that is, the interval T between the transparent substrate 1 and the second substrate 22 is, for example, 100 μm to 50 μm.
The thickness is about 0 μm, or about 100 to 150 times the thickness t of the display area. In the present embodiment, T = 15
It was 0 μm. Then, the resin sealing layer 33 and the second substrate 22 are formed in close contact with each other, and there is no space. With such a configuration, the space 1 in the conventional structure can be used.
2, the display device can be made thinner. The reason for setting the layer thickness as described above is that if the thickness of the resin sealing layer 33 is too small, the display area cannot be sufficiently protected,
In addition, the second substrate 22 cannot be securely bonded. If the resin sealing layer 33 is too thick, the resin sealing layer 3
3 has a larger side area exposed to the outside air. Resin sealing layer 3
Since the resin used in 3 transmits a small amount of moisture, the area where the resin sealing layer 33 is exposed is preferably as small as possible.

The resin sealing layer 33 contains a desiccant powder. If the desiccant is mixed before the resin sealing layer 33 is cured, and is sufficiently kneaded before the resin is cured, the desiccant can be uniformly mixed into the resin sealing layer 33. As the desiccant, a substance having a chemical adsorption property is used. Examples of the chemisorbing desiccant include, for example, oxides of alkaline earth metals such as calcium oxide and barium oxide,
Halides of alkaline earth metals such as calcium chloride,
And phosphorus pentoxide. Physically adsorptive desiccants such as silica gel are not suitable because they release adsorbed moisture at high temperatures. As described above, since the resin sealing layer 33 in which the desiccant is mixed is formed so as to cover the display area,
There is no space around the display area, and it is possible to prevent the organic EL layer 5 from being deteriorated by moisture. Also,
Due to the desiccant mixed in the resin sealing layer 33, the resin sealing layer 33 has a sufficient water absorbing ability, so that it is not necessary to install the desiccant sheet 13 conventionally installed, and the display device is made thinner accordingly. be able to. Further, the resin sealing layer 3
3 is uniformly formed over the entire display area, so that moisture in the display area can be uniformly absorbed from the entire display area. If the particle size of the desiccant powder is about 20 μm, it does not hinder the curing of the resin sealing layer 33. When an ultraviolet-curing type resin is used for the resin sealing layer 33, if the particle size of the desiccant is too large, ultraviolet rays are not evenly irradiated, and it takes time to cure the resin or the curing is incomplete. I do. For example, it is preferable to use calcium oxide as a desiccant since its particle size is about 10 μm.

The resin sealing layer 33 is made of, for example, an epoxy resin, and is preferably of a type that can be cured by mixing two liquids or irradiating ultraviolet rays. The type cured by heating is not suitable because the organic EL layer 5 may be deteriorated by heating.

The viscosity of the resin sealing layer 33 before curing is lower than that of the seal 11 used to fix the conventional cap 10, for example, 4500 cps to 50,000 c.
It is good to use one of the order of ps. Conventionally used seal 1
No. 1 has a high viscosity and is on the order of several hundred thousand cps, so it is difficult to knead and mix the desiccant powder evenly. It is difficult to uniformly form the layer 33 over the entire surface. If the viscosity is too low, it will flow before curing.

The desiccant powder is about 20 wt% to 40 wt% in weight ratio to the resin of the resin sealing layer 33 and 10 vol% in volume ratio.
~ 20 vol%. If the amount is too small, the water adsorbing property cannot be sufficiently obtained, and if the amount is too large, the viscosity of the resin decreases, and the display area cannot be completely covered. For example, 3Bond 3
If calcium oxide powder is mixed into the 112 at 25 wt%, sufficient water resistance can be ensured without lowering the viscosity of the resin or making the resin sealing layer 33 brittle.

Next, the mixing amount of the desiccant will be described in more detail. The amount of water permeating through the resin varies depending on the type of the resin. For example, in the case of a resin having a thickness of 0.5 mm using XNR5493T manufactured by Nagase Chiba, it is about 0.1% a day at 25 ° C. and 50% humidity. Transmits 6 g / m2. Assuming that one side of the EL display device is 6 cm and the thickness of the resin sealing layer 33 is 150 μm, the area where the resin sealing layer 33 is exposed is 4 × 6 × 10−2 × 150 × 10−6 = 3.6 ×. Since it is 10 @ -5 m @ 2, the amount of water permeated per day is 0.6.times.3.6.times.10@-5 =2.2.times.10@-5 g / day. When calcium oxide is used as a desiccant, about 3 g of calcium oxide required to adsorb 1 g of water is required from the ratio of molecular weight, so that the amount of calcium oxide that can completely adsorb water for 10 years is 2. 2 × 10−5 × 3 × (365 × 10) = 250 mg. Since the specific gravity of the resin is 1.3, the weight of the resin is (6 cm × 6 cm × 150 μm) × 1.3 = 700 mg. Therefore, the weight percentage of the resin is 250 / (250 + 700) ≒ 25 wt%. This corresponds to about 17 vol% in terms of volume ratio. Of course, the optimum mixing ratio of the desiccant changes depending on various factors such as the assumed storage environment, types of resin and desiccant, and the area of the EL display device. For example, if the storage environment is 3
If the humidity is 0 ° C. and the humidity is 80%, the amount of permeated water is approximately doubled. Conversely, if the amount of calcium oxide capable of adsorbing water for five years is halved. Therefore, the mixing ratio of the desiccant is
10wt% ~ 50wt% by weight ratio, 8vol% ~ 35vol% by volume ratio
It is good.

Next, a curing method in the case where an ultraviolet curing type resin is used as the resin sealing layer 33 will be described. If the UV-curable resin is, for example, 3112 resin made of Three Bond, a metal halide lamp of 10
Irradiate at 0mW / cm2 intensity for 30 seconds, total 3000mJ
/ cm2 can be cured by irradiation. However, when such energy is applied to the selection drive circuit 2 which is a thin film transistor, various characteristics such as on-off characteristics of the transistor may be changed, or the element may be destroyed. By the way, this embodiment, as described in detail below,
The material of the second substrate 22 has a high degree of freedom. Therefore, the counter electrode 6 is formed of a light-shielding conductive film, for example, a metal thin film such as a magnesium-indium alloy, a magnesium-silver alloy, an aluminum-lithium alloy, or a lithium fluoride / aluminum laminate, and the second substrate 22 is transparent. Substrate. Then, ultraviolet rays are irradiated through the second substrate 22 to cure the resin. The ultraviolet light transmitted through the second substrate 22 and applied to the resin sealing layer 33 is reflected by the counter electrode 6 and is not applied to the selection drive circuit 2, so that the characteristics of the selection drive circuit 2 do not change. Further, since the ultraviolet light reflected by the counter electrode 6 is again irradiated to the resin sealing layer 33, the irradiation efficiency of the ultraviolet light is improved. If it is necessary to make the opposing electrode 6 a transparent material such as ITO for design reasons or the like, a light-shielding film may be further formed on the opposing electrode 6.

Next, the second substrate 22 will be described. The conventional cap 10 had to be dish-shaped in order to isolate the organic EL layer 5 from the outside world. For this reason, a metal that can be easily formed by press working has been adopted as the material of the cap 10. On the other hand, in the present embodiment, the display area is sealed with the resin sealing layer 33 and the desiccant sheet 13 is not provided. The main properties are impact resistance for protecting the sealing layer 33 and non-water permeability that does not allow moisture to pass. Therefore, since the second substrate 22 does not need to be formed in a dish shape and may be a flat plate, various materials such as a metal plate, a glass plate, a resin plate of acrylic, or the like can be used. However, as described above, when the resin sealing layer 33 is formed using an ultraviolet curing type resin, the second substrate 22 is transparent because the second substrate 22 is irradiated with ultraviolet light through the second substrate 22. Glass and acrylic are best.

Also in the present embodiment, it is more effective if grooves are provided in the substrate 1 or the second substrate 22 opposed thereto and the desiccant 14 is disposed as in the second embodiment.

In each of the above embodiments, the case where a color filter or a fluorescent conversion layer is used as a color element has been described. However, when a color display is not required, the color filter and the fluorescent conversion layer are unnecessary. It is.

In each of the above embodiments, the organic EL layer is exemplified as the light emitting element layer. However, the same applies to a display device having a light emitting layer other than the organic EL layer, such as an LED or a vacuum display device. Can be implemented. Just organic E
Since the L layer is particularly vulnerable to moisture, the present application can be said to be most effective when applied to a display device using an organic EL layer.

In each of the above embodiments, T
Although the structure of the FT has been described as a bottom gate type, the present invention is not limited thereto, and a so-called top gate type in which a gate electrode is provided above an active layer may be used.

[0078]

As described above, according to the display device of the present invention, the resin mixed with the desiccant is disposed between the pair of substrates. Can be prevented from being deteriorated by moisture.

The pair of substrates are adhered to each other by a seal formed around the display area, and a desiccant is mixed in the seal. Moisture permeation from the substrate is almost negligible, and moisture permeation from the seal is adsorbed by the desiccant, so that water hardly enters the display device, and therefore, the display area is deteriorated by the water. Can be prevented.

Further, around at least one of the substrates,
Since the groove has a concave shape and the desiccant is sealed in the groove, a sufficient amount of the desiccant in the groove can be disposed, and the permeation of moisture can be more reliably prevented.

Further, since the groove is covered with a seal for bonding a pair of substrates to each other, the desiccant in the groove does not come into contact with the outside air, does not absorb unnecessary moisture, and can be used for a longer time. Over the seal can be adsorbed.

Further, of the pair of substrates, a color element is provided between the second substrate facing the first substrate on which the display region is formed and the display region, and the second substrate emits visible light. Since it is a transparent substrate that transmits light, the aperture ratio of the display pixels is improved, and when a TFT that drives the display area is provided, the degree of freedom in determining the size and the driving capability can be increased.
The process can be simplified by providing it on another substrate facing the substrate on which is formed, and furthermore, display deterioration due to moisture can be prevented.

Further, a light having a predetermined color is converted into light of a different color between a display area and a second substrate of the pair of substrates facing the first substrate on which the display area is formed. It has a fluorescence conversion layer, between the fluorescence conversion layer and the display area,
Since a spacer made of a desiccant is provided, moisture in the display device can be absorbed without disposing a desiccant sheet,
In addition, since the spacer is made of a desiccant, it is not necessary to separately provide a desiccant other than the simple spacer, so that the aperture ratio of the display device is improved.

Further, since the resin mixed with the desiccant is formed so as to cover the display area, it is possible to uniformly absorb moisture from the entire surface of the display area, which is more effective than disposing the desiccant sheet. Can adsorb moisture. Further, since there is no need to arrange a desiccant sheet, the display device can be made thinner.

Further, a resin formed so as to cover the display region is filled between the second substrate facing the first substrate having the display region formed thereon and the display region. As a result, unnecessary space is eliminated, deterioration due to moisture can be prevented, and the display device can be made thinner.

Further, the desiccant described above is a substance having a chemical adsorption property, and is a powder having a particle size of 20 μm or less.
Since 10 wt% or more and 50 wt% or less are mixed in the resin sealing layer, the hardening of the resin mixed with the desiccant is not hindered, and the viscosity of the resin before hardening and the hardness of the resin after hardening are reduced. Without this, sufficient moisture absorption can be achieved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of an organic EL display device of the present invention.

FIG. 2 is a view showing a second embodiment of the organic EL display device of the present invention.

FIG. 3 is a sectional view showing a third embodiment of the organic EL display device of the present invention.

FIG. 4 is a sectional view showing a fourth embodiment of the organic EL display device of the present invention.

FIG. 5 is a sectional view showing a fifth embodiment of the organic EL display device of the present invention.

FIG. 6 is a sectional view showing a sixth embodiment of the organic EL display device of the present invention.

FIG. 7 is a view showing a seventh embodiment of the organic EL display device of the present invention.

FIG. 8 is a diagram of a conventional organic EL display device.

FIG. 9 is a sectional view of a conventional organic EL display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating substrate 2 Selection drive circuit 4, 23 Pixel electrode 5 Organic EL layer 6, 25 Counter electrode 11, 26, 33 Seal 14 Desiccant

Claims (13)

[Claims] 1. A display device comprising a display region including a white light emitting element disposed between a pair of substrates, wherein a resin mixed with a desiccant is disposed between the pair of substrates. A display device characterized by the above-mentioned. 2. The method according to claim 1, wherein the pair of substrates are adhered to each other by a seal made of the resin and formed at least around the display area, and a desiccant is mixed in the seal. The display device according to claim 1. 3. A display device in which a display region including a white light emitting element is arranged between a pair of substrates, wherein at least one of the substrates has a concave-shaped groove, and the groove has a concave shape. A display device in which a desiccant is sealed. 4. The substrate according to claim 1, wherein the pair of substrates are bonded to each other by a seal made of the resin and formed in a ring shape surrounding at least the display area, and the groove is covered by the seal. The display device according to claim 3. 5. The display device according to claim 1, wherein the display area has a first electrode, an electroluminescent layer, and a second electrode. 6. A second substrate provided with a color element between a second substrate of the pair of substrates facing the first substrate on which the display region is formed, and the second substrate. 6. A transparent substrate which transmits visible light.
The display device according to claim 1. 7. A spacer comprising a desiccant between a second substrate of the pair of substrates facing the first substrate on which the display region is formed and the display region. The display device according to claim 5, wherein: 8. A display device in which a display region including a white light emitting element is disposed between a pair of substrates, the display device including a resin mixed with a desiccant formed to cover the display region. A display device characterized by the above-mentioned. 9. A resin formed so as to cover the display area, between a second substrate of the pair of substrates facing the first substrate on which the display area is formed, and the display area. 9. The display device according to claim 8, wherein is filled. 10. A transparent first substrate, a plurality of selection driving circuits arranged on the first substrate, a plurality of pixel electrodes respectively arranged corresponding to the selection driving circuits, In an electroluminescent display device including a light-emitting element layer formed over a pixel electrode and a counter electrode facing the plurality of pixel electrodes with the light-emitting element layer interposed therebetween, the selection drive circuit, the pixel electrode, and the light-emitting element A resin sealing layer formed so as to cover a display region including an element layer and the counter electrode, and mixed with a desiccant; and a second resin sealing layer disposed on the resin sealing layer so as to face the first substrate. A display device comprising: a substrate. 11. The display device according to claim 1, wherein the desiccant is a substance having a chemical adsorption property. 12. The display device according to claim 11, wherein the desiccant is a powder having a particle size of 20 μm or less. 13. The display device according to claim 12, wherein the desiccant is mixed in the resin sealing layer in an amount of 10% by weight or more and 50% by weight or less with respect to the resin.