JP2007027142A - Manufacturing method of display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device sealing a light-emitting layer emitting light by itself like an organic EL layer inside, being capable of preventing display deterioration by moisture, and designing without constraint of size and capability of a TFT driving a light-emitting layer. <P>SOLUTION: A seal 11 bonding a first substrate 1 and a cap 10 and sealing a display region is mixed with a powdery drying agent. Since moisture permeation from a substrate surface pinching the display region can be ignored and moisture permeating the seal 11 is absorbed by the drying agent, deterioration of a light-emitting layer by moisture can be prevented. And also, the display region is protected from water by covering the display region with a resin sealing layer 33 made of a resin mixed with the drying agent. Also, since a groove is provided on the substrate, and a drying agent 14 is arranged there, moisture is absorbed more reliably. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a display device including an electroluminescence (hereinafter referred to as “EL”) element on a substrate, and in particular, an organic EL layer and a thin film transistor (hereinafter referred to as “TFT”). ). The sealing structure of the active matrix organic EL display device provided with

  A display device using an organic EL is a self-luminous element that emits light by flowing current, consumes less power than a CRT, and does not have a viewing angle problem like an LCD. Thus, organic EL display devices have attracted attention as display devices that replace CRTs and LCDs. FIG. 8A is a plan view showing a conventional organic EL display device, and FIG. 8B is a sectional view taken along line A-A ′. A plurality of selective drive circuits 2 are arranged for each pixel on the transparent substrate 1. A pixel electrode 4 is connected to each selection drive circuit 2, and an organic EL layer 5 and a counter electrode 6 are disposed so as to cover them. A driver circuit 7a for controlling the selection drive circuit 2 or applying a predetermined voltage to the pixel electrode 4 around the display area composed of 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 the terminal 9 by wiring 8. A cap 10 made of a metal such as aluminum is disposed so as to cover these structures, and is fixed to the transparent substrate 1 using a seal 51. A space 12 between the cap 10 and the transparent substrate 1 is filled with dry nitrogen, and a desiccant sheet 13 is installed on the inner surface of the cap 10.

  The selection drive circuit 2 includes a plurality of semiconductor elements made of, for example, 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 rendered conductive by the output of the driver circuit 7a via the second TFT, Current flows between the two. The light emitting layer 5 is configured to emit light when an electric current flows therethrough, and emits light with an intensity corresponding to the amount of current flowing between the pixel electrode 4 and the counter electrode 6. The generated light is visible through the transparent substrate 1 in the downward direction of the sectional view.

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

FIG. 9 is a cross-sectional view showing one pixel in more detail. A gate electrode 41 made of a refractory metal such as Cr or Mo is disposed on an insulating substrate 1 made of quartz glass, alkali-free glass or the like. On the gate electrode 41, a gate insulating film 42 made of SiN / SiO 2 and an active layer 43 made of a polysilicon film are laminated in this order. The active layer 43 is provided with a channel 43c above the gate electrode 41 and a source 43s and a drain 43d of a high concentration region on both sides of the channel 43c. The source 43 s and the drain 43 d are ion-doped using the stopper insulating film 44 on the channel 43 c as a mask, and further, both sides of the gate electrode 41 are covered with a resist and ion-doped to form a low-concentration region and a high-concentration on both sides of the gate electrode 41. This is a so-called LDD structure having a concentration region. The selective drive circuit 2 is a generic term for the gate electrode 41, the gate insulating film 42, and the active layer 43.

Then, an interlayer insulating film 45 is formed on the entire surface of the gate insulating film 42, the active layer 43, and the stopper insulating film 44 by laminating an SiO 2 film, an SiN film, and an SiO 2 film in this order, and a contact provided corresponding to the drain 43d. The hole is filled with a metal such as Al and connected to the drive power supply line 46. Further, a planarization 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 planarization insulating film 47, and ITO (Indium) which is in contact with the source 13s through the contact hole is formed.
A transparent electrode 3 made of thin oxide or the like is disposed.

  The organic EL layer 5 includes a first hole transport layer 5a made of MTDATA (4,4-bis (3-methylphenylphenylamino) biphenyl) and a second hole made of TPD (4,4,4-tris (3-methylphenylphenylamino) triphenylanine). The light-emitting element layer includes a hole transport layer 5b, a light-emitting layer 5c made of Bebq2 (10-benzo [h] quinolinol-beryllium complex) containing a quinacridone derivative, and an electron transport layer 5d made of Bebq2. The above configuration is described in, for example, Japanese Patent Application No. 11-22183, Japanese Patent Application No. 11-22184, and the like.

  Further, the organic EL layer 5 is configured such that holes injected from the anode and electrons injected from the cathode are recombined inside the organic EL layer 5 to excite the organic molecules forming the organic EL layer 5 to generate excitons. Arise. Light is emitted from the organic EL layer 5 in the process of radiation deactivation of the excitons, and the light is emitted from the transparent anode through the transparent insulating substrate 1 to emit light.

  The TFT and the organic EL layer 5 thus laminated are covered with a cap 10 made of a metal such as aluminum. The cap 10 is bonded 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 from there, or peeling occurs between the organic EL layer 5 and the counter electrode 5. As a result, dark spots are generated and display quality is significantly degraded. The cap 10 protects the display area and the driver circuit 7 from physical shocks and plays a role of preventing moisture from entering. For this reason, it has a dish-like shape so as to cover the display area. Further, in order to prevent invading moisture, the space 12 in the cap 10 is filled with an inert gas such as dry nitrogen or helium, and a desiccant sheet 13 is further disposed. Further, there may be a further step at the installation location for disposing the desiccant sheet 13. Such a configuration is disclosed in, for example, Japanese Patent Laid-Open No. 9-148066.

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

  The desiccant sheet 13 has a configuration in which a desiccant powder is wrapped with a porous film, and has a thickness of about 1 mm. This is extremely thick as compared with the thickness of the display area of about several μm, and the space 12 is created due to the configuration of being fixed to the inner surface of the cap 10, so that the thickness of the entire organic EL display device is reduced. There was a limit.

  By the way, in the structure of the above-described conventional display device, since the direction of light emission from the organic EL layer 5 is on the insulating substrate 1 side provided with the TFT, the emitted light is blocked by the TFT and the display pixel 1. There was a limit to increasing the aperture ratio.

  Further, in 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. Therefore, the size of the TFT and the ability of the TFT are also limited.

Therefore, the present invention aims to provide an organic EL display device that has a sealing structure that can more reliably prevent moisture from adhering to the organic EL layer 5 and that can reduce the overall thickness. In addition to improving the aperture ratio of the display pixel and increasing the degree of freedom in determining the size and driving capability of the TFT for driving the EL element, the color element is provided on another substrate facing the substrate on which the TFT is formed. An object of the present invention is to provide an organic EL display device capable of simplifying the process.

  The present invention has been made to solve the above problems, and in a display device in which a display region which emits light by voltage application is sealed between a pair of substrates, a resin mixed with a desiccant is disposed between the pair of substrates. Display device.

  The pair of substrates are bonded to each other by a seal formed so as to surround the display area, and a desiccant is mixed in the seal.

  Furthermore, a recess-shaped groove is provided around at least one of the substrates, and a desiccant is sealed in the groove.

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

  Further, a color element is provided between the display substrate and the second substrate facing the first substrate on which the display region is formed, and the second substrate is transparent to transmit visible light. It is a substrate.

  Further, a fluorescence conversion layer that converts light having a predetermined color into light of a different color between a display substrate and a second substrate that faces the first substrate on which the display region is formed, of the pair of substrates. A spacer made of a desiccant is provided between the fluorescence conversion layer and the display region.

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

  Further, a resin formed to cover the display region is filled between the display region and the second substrate facing the first substrate on which the display region is formed, of the pair of substrates.

  In addition, a transparent first substrate, a plurality of selection drive circuits arranged on the first substrate, a plurality of pixel electrodes respectively connected to the selection drive circuit, and an electro formed to cover the plurality of pixel electrodes In an electroluminescence display device having a luminescence layer, and a plurality of pixel electrodes and a counter electrode facing each other through the electroluminescence layer, the display area is formed to cover all of the display area including the selective drive circuit, the pixel electrode, the electroluminescence layer, and the counter electrode. The display device includes a resin sealing layer mixed with a desiccant and a second substrate disposed on the outer side of the resin sealing layer so as to face 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, and is mixed in the resin sealing layer by 10 wt% or more and 50 wt% or less.

  According to the display device of the present invention, since the resin in which the desiccant is mixed is disposed between the pair of substrates, the desiccant adsorbs moisture that has entered the display device, so that the display area is deteriorated by moisture. Can be prevented.

  The pair of substrates are bonded to each other by a seal formed so as to surround the display area, and a desiccant is mixed in the seal. The moisture permeation from the substrate is almost negligible, and the moisture permeation from the seal is adsorbed by the desiccant, so that the moisture hardly penetrates into the display device, and therefore the display area is deteriorated by moisture. Can be prevented.

  Further, since at least one of the substrates has a recess-shaped groove, and the desiccant is sealed in the groove, a sufficient amount of the desiccant in the groove can be disposed, and more reliably. In addition, it is possible to prevent moisture permeation.

  Furthermore, since this groove is covered with a seal that adheres a pair of substrates to each other, the desiccant in the groove does not come into contact with the outside air, does not adsorb unnecessary moisture, and seals for a longer period of time. Permeated moisture can be adsorbed.

In addition, a color element is provided between the display substrate and the second substrate facing the first substrate on which the display region is formed, and the second substrate is transparent to transmit visible light. Since the substrate has a TFT that improves the aperture ratio of the display pixel and drives the display region, the degree of freedom in determining the size and driving capability can be increased, and the color element is opposed to the substrate on which the TFT is formed. By providing it on the separate substrate, the process can be simplified, and display deterioration due to moisture can be prevented.

  Further, a fluorescence conversion layer that converts light having a predetermined color into light of a different color between a display substrate and a second substrate that faces the first substrate on which the display region is formed, of the pair of substrates. Since a spacer made of a desiccant is provided between the fluorescence conversion layer and the display area, moisture in the display device can be adsorbed without arranging a desiccant sheet. Since it is made of a desiccant, it is not necessary to arrange a desiccant separately from a simple spacer, so that the aperture ratio of the display device is improved.

  In addition, since the resin mixed with the desiccant is formed so as to cover the display area, it can adsorb moisture evenly from the entire surface of the display area, and more effectively absorbs moisture than arranging the desiccant sheet. Can be adsorbed. Moreover, since it is not necessary to arrange a desiccant sheet, the display device can be made thinner.

  Furthermore, between the second substrate facing the first substrate on which the display area is formed and the display area among the pair of substrates, the resin formed so as to cover the display area is filled. 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, and 10 wt% or more and 50 wt% or less is mixed in the resin sealing layer. Sufficient moisture absorption can be achieved without hindering the curing of the resin and without lowering the viscosity of the resin before curing and the hardness of the resin after curing.

<First Embodiment>
FIG. 1A is a plan view of an organic EL display device according to the first embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line AA ′. The same number is attached | subjected about the structure similar to the past, and detailed description is abbreviate | omitted. A selective drive circuit 2 is disposed for each pixel on the transparent substrate 1, a pixel electrode 4 is disposed through a planarization insulating film 3, and an organic EL layer 5 and a counter electrode 6 are disposed so as to cover them. The selective 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 the terminal 9 by wiring 8. The display area is covered with a metal cap 10 that is a second substrate disposed to face the substrate 1, and a desiccant sheet 13 is disposed inside the cap 10. The above structure is the same as that of a conventional display device.

A feature of the present embodiment is that a seal 11 for bonding the cap 10 and the transparent substrate 1 is used.
This is the point that the powder of the desiccant is mixed.

  The seal is formed of a synthetic resin such as acrylic, but the synthetic resin transmits a minute amount of moisture. The amount of moisture permeation varies depending on the type of resin. For example, XNR5493T manufactured by Nagase Chiba is a resin with relatively low moisture permeability, but it permeates 7 g / m2 of moisture per day in an environment of 60 ° C and 90% humidity. To do. (Catalog value) If such permeated moisture adheres to the display area before being adsorbed to the desiccant sheet 13, there is a possibility that the organic EL layer 5 may be deteriorated. However, in this embodiment, since the desiccant powder is mixed in the seal 11, there is almost no moisture that passes through the seal.

The seal 11 is made of, for example, an epoxy resin, and is preferably a type that is cured by mixing two liquids or irradiating with ultraviolet rays. A type that is 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 about 100,000 cps to 300,000 cps.
In order to mix the desiccant evenly, it is desirable to use a resin having as low a viscosity as possible so long as the resin does not flow before curing.

The desiccant is mixed before the seal 11 is cured, and can be evenly mixed into the seal 11 when the resin is cured after sufficiently kneading. A chemisorbable substance is used as the desiccant. 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 unsuitable because they release adsorbed moisture at high temperatures.
<Second Embodiment>
FIG. 2A is a plan view of the organic EL display device according to the first embodiment of the present invention, and FIG. 2B is a sectional view taken along the line AA ′. The same number is attached | subjected about the structure similar to 1st Embodiment, and detailed description is abbreviate | omitted. The feature of this 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 certain degree of viscosity so that the seal 11 does not flow before curing. Therefore, it is difficult to mix the desiccant evenly. Moreover, in order not to lose the viscosity of the resin before curing, there is a limit to the amount of desiccant that can be mixed. And if the width | variety of the seal | sticker 11 is thin, the desiccant mixed will also decrease, and there exists a possibility that all the permeate | transmitted water | moisture contents cannot be adsorbed. In the present embodiment, a groove is provided in the transparent insulating substrate 1 and a desiccant 14 is disposed here. The desiccant 14 may be mixed with a resin having a low viscosity and then poured into the groove to be cured, and then the seal 11 may be formed. The desiccant 14 in the groove may have a large particle size. The granular desiccant may be fixed with a resin having a low viscosity, or the desiccant 14 may be formed in accordance with the shape of the groove and may be fitted. In any case, a sufficiently large amount of desiccant 14 can be disposed in the groove as compared with the amount of water that permeates the seal 11. Since most of the moisture that has entered the seal 11 is adsorbed by the desiccant mixed in the resin in the groove, it hardly penetrates into the display device.

  In addition, if the desiccant 14 is exposed to the outside, abundant moisture contained in the outside air is adsorbed, and the adsorption capacity is immediately lost. Therefore, the desiccant 14 is preferably disposed under the seal 11 so as not to be exposed to the outside. Of course, it is more effective if a desiccant is mixed in the seal 11 as well.

Further, in the present embodiment and the fourth and sixth embodiments described below, the groove is formed only on the first substrate 1, but the groove is also formed on the opposing substrate (cap 10 in this embodiment). However, it is more effective to arrange a desiccant here.
<Third Embodiment>
FIG. 3 shows a third embodiment, and is a cross-sectional view of an organic EL display device that includes a color filter 21 as a color element and includes a first substrate 1 ′ and a second substrate 22. The same number is attached | subjected about the structure similar to 1st Embodiment, and detailed description is abbreviate | omitted. In the present embodiment, unlike the first embodiment, 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 color display is performed by the color filter 21 as light of each color.

  The pixel electrode 23 includes a planarization insulating film 3 and a lower layer 23a made of an opaque conductive material such as molybdenum (Mo) formed on a surface including the contact hole provided in the planarization insulating film 3, and ITO formed thereon. And a laminated structure with the upper layer 23b. The upper layer 23a of Mo and the lower layer 23b of ITO may have the same shape. The lower layer 23a is provided to reflect light generated in the organic EL layer 5 and to emit light efficiently. The opaque conductive material is not limited to Mo, and may be a metal such as aluminum (Al) or silver (Ag). The reason why the upper ITO layer 23b is provided thereon is that the work function is high and the organic EL layer 5 emits light efficiently.

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

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

  Light emitted from the organic EL layer 5 is emitted from the transparent counter electrode 25 to the outside (upward in the drawing as indicated by arrows in the drawing). That is, light is emitted to the insulating substrate 22 side where no TFT exists. 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 on the entire display area as shown in FIG.

  Hereinafter, the color filter 21 which is a color element formed on the transparent and insulating second substrate 22 will be described. A color filter 21 is provided as a color element on the display panel of the organic EL display device described above. As shown in FIG. 3, a color filter 21 having 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 counter electrode 25 side.

  The color filter 21 is provided on the counter electrode 25 side of the organic EL layer 5 of the second substrate 22. Then, the second substrate 22 and the first substrate 1 ′ are fixed by adhering the periphery thereof with a seal 26 having an adhesive function. The color filter 21 is provided with each color corresponding to each display pixel 1 composed of the organic EL layer 5 and the TFT. A black matrix (BM) 27 that blocks light may be provided between the colors. 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 element provided on the organic EL layer 5. That is, when a color filter having R, G, and B is used as in the present embodiment, white light is used as light emitted from the organic EL layer 5. In order to emit white light, the material of the organic EL layer 5 is a ZnBTZ complex, or a laminate of TPD (aromatic diamine) / p-EtTAZ (1,2,4-triazole derivative) / Alq. (However, “Alq” means partial doping with Neil Red, which is a red light-emitting pigment.)

Here, a sealing agent for bonding the transparent insulating substrate 22 and the insulating substrate 2 will be described. The seal 26 for bonding both the substrates 1 'and 22 is made of an epoxy resin, and a desiccant such as calcium oxide, phosphorus pentoxide, calcium chloride or the like is mixed therein. By mixing the desiccant into the sealant, moisture in the space formed by both the substrates 1 ′ and 22 and the seal 26 can be absorbed by the desiccant, so that the moisture adversely affects each layer made of an organic material. Display deterioration due to can be prevented. The composition of the seal 26 is basically the same as that of the seal 11 of the first embodiment. Since the desiccant sheet 13 cannot be disposed in the case of emitting light from above as in the present embodiment, the desiccant for the seal 26 is extremely important.

  As described above, according to the organic EL display device of the present invention, since light can be emitted from the second substrate 22 side provided with the color filter 21, the light is not blocked by the TFT. The aperture ratio of the display pixel 1 can be designed to the maximum, and the degree of freedom for determining the size and driving capability of the TFT that drives the organic EL layer 5 can be increased.

  Moreover, since the aperture ratio of the display pixel 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, the light emitting material used as the organic EL layer 5 is only one kind of white light emitting material, and a color filter composed of three colors of R, G, and B is formed on the transparent substrate 21. Since only the color filter forming surface and the counter electrode 25 side of the organic EL layer 5 are adhered to each other, three types of organic EL materials are used in the organic EL layer 5 to emit the three primary colors as in the prior art. The process can be greatly simplified as compared with the formation.

Furthermore, since the emitted light is emitted as the color of the display pixel from the color filter side provided on the counter electrode side, the area of the emitted light is larger than that emitted from the TFT substrate side as in the prior art, and the color display is bright and clear. Can be obtained.
<Fourth embodiment>
FIG. 4 is a sectional view of an organic EL display device according to the fourth embodiment of the present invention. The same number is attached | subjected about the structure similar to 3rd Embodiment, and detailed description is abbreviate | omitted.

A feature of the present 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. As in the second embodiment, the desiccant 14 in the groove is formed by mixing and pouring a sufficient amount of desiccant into a resin having high fluidity, so that the moisture adsorption efficiency is high.
<Fifth embodiment>
FIG. 5 shows a cross-sectional view of the display device when the fluorescence conversion layer 31 is used as a color element. As shown in the figure, the third embodiment differs from the third embodiment in that a fluorescent conversion layer 31 is formed on the 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 point used 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, for example, a layer that receives blue light and emits light of a predetermined color according to the intensity thereof. Therefore, light can be emitted in a predetermined color without using a color filter, and the fluorescence conversion layer 31 emits light by itself, so that the amount of light is not attenuated unlike a color filter.

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

A spacer 32 is disposed between the fluorescence conversion layer 31 and the counter electrode 25. The spacer 32 holds the distance between the fluorescence conversion layer 31 and the counter electrode 25. Spacer 32
The diameter may be such that the interval can be maintained, for example, about several μm to several hundred μm.

  The greatest feature of this embodiment is that the spacer 32 is formed of a desiccant such as calcium oxide, phosphorus pentoxide, calcium chloride or 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 resin or the like.

  Below, 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. The fluorescence conversion layer 31 has a function of converting the color of the irradiated colored light into another color. Therefore, when obtaining the three primary colors R, G, and B from a color display device using a blue light emitting material for the organic EL layer 5, the fluorescence conversion layer 31 converts the blue color into red or green. Must be formed using materials.

  When the blue light emitted from the organic EL layer 5 is converted into red light, the organic EL layer 5 is converted into 4-dicyanomethylene-2-methyl-6- (p-dimethylaminostillin) -4H-pyran (DCM). ) Or the like. By doing so, red can be emitted from the display pixel.

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

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

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

  In the present embodiment, the case where the light emitted from the organic EL layer 5 is blue has been described. However, the present invention is not limited thereto, and the light from the organic EL layer 5 may be red or green. . At that time, when the organic EL layer 5 that emits red light is used, the fluorescence 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 that converts green to red and blue.

  As described above, since light can be emitted from the transparent insulating substrate 21 side provided with the fluorescence conversion layer 31, light is not blocked by the TFT, so that the aperture ratio of the display pixel is designed to the maximum. In addition, it is possible to increase the degree of freedom in determining the TFT size and driving capability.

  Moreover, since the aperture ratio of the display pixel 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, in this embodiment, since the emitted light is emitted from the fluorescent conversion layer 31 provided on the anode, the area for emitting the color is larger than that emitted from the TFT substrate side as in the prior art, and the color is bright and clear. An indication can be obtained.

Moreover, since it is a form which emits light from a drawing similarly to 3rd Embodiment, since the desiccant sheet | seat 13 cannot be arrange | positioned, the desiccant in resin becomes very important.
<Sixth Embodiment>
FIG. 6 shows a partial cross-sectional view of an organic EL display device according to the 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 formed by etching the insulating substrate 2 with a mask having an opening only in the region of the groove 25.

  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 sealing agent. After sealing, the substrates 2 and 22 are bonded by the seal 26 to complete the organic EL display device.

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

As described above, the moisture adsorbed on the seal 26 can be captured by the desiccant 14 enclosed in the groove, and further, the spacer 32 serving as the desiccant is used between the transparent insulating substrate 1 ′ and the counter electrode 25. Since moisture can be captured, deterioration of the organic material due to moisture and display deterioration associated therewith can be prevented.
<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 an AA ′ cross-sectional view thereof. The same number is attached | subjected about the structure similar to the past, and detailed description is abbreviate | omitted.

  The present embodiment is characterized in that the resin sealing layer 33 is formed so as to cover the entire surface of the display area. A 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, about 100 μm to 500 μm, or about 100 times to 150 times the thickness t of the display region. In this embodiment, T = 150 μm. The resin sealing layer 33 and the second substrate 22 are formed in close contact with each other, and there is no space. By adopting such a configuration, the space 12 in the conventional structure is not generated, so that the display device can be made thinner accordingly. The reason why the layer thickness is as described above is that if the thickness of the resin sealing layer 33 is too thin, the display area cannot be sufficiently protected, and the second substrate 22 cannot be securely bonded. Moreover, when the resin sealing layer 33 is too thick, the side area where the resin sealing layer 33 is exposed to the outside air becomes large. Since the resin used for the resin sealing layer 33 transmits some moisture, it is desirable to make the area where the resin sealing layer 33 is exposed as small as possible.

The resin sealing layer 33 is mixed with powdered desiccant. The desiccant is mixed before the resin sealing layer 33 is cured, and can be evenly mixed in the resin sealing layer 33 by thoroughly kneading and then curing the resin. A chemisorbable substance is used as the desiccant. 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 unsuitable because they release adsorbed moisture at high temperatures. Thus, since the resin sealing layer 33 mixed with the desiccant is formed so as to cover the display area, there is no space around the display area, and the organic EL layer 5 is prevented from being deteriorated by moisture. can do. Moreover, since the resin sealing layer 33 has sufficient water absorption capability due to the desiccant mixed in the resin sealing layer 33, it is not necessary to install the desiccant sheet 13 which has been conventionally installed, and accordingly the display device is Can be thinned. Furthermore, since the resin sealing layer 33 is formed uniformly over the entire display area, moisture in the display area can be evenly absorbed from the entire area. In addition, if the particle size of the powder of the desiccant is about 20 μm, it does not hinder the curing of the resin sealing layer 33. When an ultraviolet curable resin is used for the resin sealing layer 33, if the particle size of the desiccant is too large, the ultraviolet rays are not evenly irradiated, and it takes time to cure the resin, or the curing becomes incomplete. To do. For example, if calcium oxide is used as the desiccant, the particle size is about 10 μm, which is preferable.

  The resin sealing layer 33 is made of, for example, an epoxy resin, and is preferably a type that is cured by mixing two liquids or irradiating with ultraviolet rays. A type that is 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 may be lower than that of the seal 11 used for fixing the conventional cap 10, for example, about 4500 cps to 50000 cps. Since the seal 11 used in the past has a high viscosity of about several hundred thousand cps, it is difficult to mix the desiccant powder evenly, and bubbles are mixed when the second substrate 22 is installed. For example, it is difficult to uniformly form the resin sealing layer 33 on the entire surface. Also, if the viscosity is too low, it will flow before curing.

  The desiccant powder is mixed with the resin of the resin sealing layer 33 in a weight ratio of about 20 wt% to 40 wt% and in a volume ratio of 10 vol% to 20 vol%. If the amount is too small, the moisture adsorptivity cannot be sufficiently obtained. If the amount is too large, the viscosity of the resin is lowered and the display area cannot be completely covered. For example, when 25 wt% of calcium oxide powder is mixed into ThreeBond 3112, the resin viscosity does not decrease and the resin sealing layer 33 does not become brittle, and sufficient water resistance can be secured.

Next, the amount of the desiccant mixed will be described in more detail. The amount of water that permeates through the resin varies depending on the type of the resin. For example, if the resin is 0.5 mm thick using XNR5493T manufactured by Nagase Ciba, it is about 0. 0 per day in an environment of 25 ° C. and 50% humidity. It penetrates 6g / m2. When one side of the EL display device is 6 cm and the film 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 × 10-5m2
Therefore, the amount of moisture permeated per day is 0.6 × 3.6 × 10 −5 = 2.2 × 10 −5 g / day. When calcium oxide is used as a desiccant, the amount of calcium oxide required to adsorb 1 g of water is about 3 g from the ratio of molecular weight, so the amount of calcium oxide that can completely adsorb 10 years of water is 2. 2 * 10 <-5> * 3 * (365 * 10) = 250 mg
It is. Since the resin has a specific gravity of 1.3,
(6 cm × 6 cm × 150 μm) × 1.3 = 700 mg
It is. Therefore, the weight percent of resin is
250 / (250 + 700) ≒ 25wt%
It becomes. This corresponds to about 17 vol% when converted to a volume ratio. Of course, the optimum mixing ratio of the desiccant varies depending on various factors such as an assumed storage environment, types of resin and desiccant, and area of the EL display device. For example, if the storage environment is 30 ° C. and 80% humidity, the water permeation amount is approximately doubled. Conversely, if the amount of calcium oxide capable of adsorbing moisture for 5 years is halved. Therefore, the mixing ratio of the desiccant may be 10 wt% to 50 wt% by weight and 8 vol% to 35 vol% by volume.

  Next, a curing method when an ultraviolet curable resin is used as the resin sealing layer 33 will be described. If the ultraviolet curable resin is, for example, 3112 resin manufactured by ThreeBond, it can be cured by irradiating a metal halide lamp with an intensity of 100 mW / cm 2 for 30 seconds and irradiating a total of 3000 mJ / cm 2. However, if such energy is applied to the selective driving circuit 2 which is a thin film transistor, various characteristics such as on / off characteristics of the transistor may change or the element may be destroyed. By the way, this embodiment has a high freedom degree regarding the material of the 2nd board | substrate 22, so that it may explain in full detail below. 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. A substrate is used. Then, the resin is cured by irradiating ultraviolet rays through the second substrate 22. The ultraviolet rays that have passed through the second substrate 22 and are applied to the resin sealing layer 33 are reflected by the counter electrode 6 and are not applied to the selection drive circuit 2, so that the characteristics of the selection drive circuit 2 do not change. Moreover, since the ultraviolet-ray reflected by the counter electrode 6 is again irradiated to the resin sealing layer 33, the irradiation efficiency of an ultraviolet-ray improves. If it is necessary for the counter electrode 6 to be made of a transparent material such as ITO for design reasons, a light shielding film may be further formed on the counter electrode 6.

  Next, the second substrate 22 will be described. The conventional cap 10 needs to have a dish-like shape 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. In contrast, in the present embodiment, the display area is sealed with the resin sealing layer 33 and the desiccant sheet 13 is not provided. Therefore, the characteristics required for the second substrate 22 are resin from physical impact from the outside. The impact resistance that protects the sealing layer 33 and the non-water permeability that does not transmit moisture are mainly used. Therefore, the second substrate 22 does not need to be formed in a dish shape, and may be a flat plate. Therefore, various materials such as a metal, a resin plate made of glass, acrylic, and the like can be used. However, as described above, when the resin sealing layer 33 is formed using an ultraviolet curable resin, the second substrate 22 is transparent because it transmits the second substrate 22 and emits ultraviolet rays. Glass and acrylic are the best.

  Also in this embodiment, it is still more effective if a groove is provided in the substrate 1 or the second substrate 22 facing the substrate and the desiccant 14 is disposed as in the second embodiment.

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

  In each of the above-described embodiments, the organic EL layer is exemplified as the light-emitting element layer. However, the present invention can be similarly applied to a display device having a light-emitting layer other than the organic EL layer such as an LED or a vacuum display device. . However, since the organic EL layer is particularly vulnerable to moisture, the present application can be said to be most effective when applied to a display device using the organic EL layer.

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

It is a figure which shows 1st Embodiment of the organic electroluminescence display of this invention. It is a figure which shows 2nd Embodiment of the organic electroluminescence display of this invention. It is sectional drawing which shows 3rd Embodiment of the organic electroluminescent display apparatus of this invention. It is sectional drawing which shows 4th Embodiment of the organic electroluminescent display apparatus of this invention. It is sectional drawing which shows 5th Embodiment of the organic electroluminescent display apparatus of this invention. It is sectional drawing which shows 6th Embodiment of the organic electroluminescence display of this invention. It is a figure which shows 7th Embodiment of the organic electroluminescence display of this invention. It is a figure of the conventional organic electroluminescence display. It is sectional drawing of the conventional organic electroluminescence display.

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 (4)

In the manufacturing method of the electroluminescence display device,
Forming a self-luminous element in the display area of the first substrate;
Forming a light-shielding film on the self-luminous element;
Forming an ultraviolet curable resin in the peripheral region of the self-luminous element;
A transparent second substrate is disposed at a position facing the first substrate having the display area,
A method of manufacturing a display device, wherein the ultraviolet curable resin is irradiated with ultraviolet rays through the second substrate. 2. The method for manufacturing a display device according to claim 1, wherein the light shielding film is formed so as to cover all of the self-light-emitting elements. The method for manufacturing a display device according to claim 1, wherein the light shielding film includes any one of magnesium, indium alloy, magnesium, silver alloy, aluminum, lithium alloy, and lithium fluoride. 2. The method for manufacturing a display device according to claim 1, wherein a desiccant is mixed in the ultraviolet curable resin.

Images