KR100656192B1 - Top-emission type organic light emitting display device - Google Patents

Abstract

Disclosed is a top emission type organic EL display device. The transparent encapsulation layer is disposed spaced apart while facing the substrate provided with the TFT electrode on the upper surface, and a sealant is added along the entire circumference of the space between them. An organic light emitting unit having a structure in which a light emitting organic layer is sandwiched between the first electrode layer and the transparent second electrode layer is stacked on the TFT electrode so that the second electrode layer faces the encapsulation layer. In order to remove moisture in the space of the device, a transparent dehumidifying thin film layer is disposed between the second electrode layer and the encapsulation layer. In addition, a hydrogen scavenger is arranged to be connected within the space of the device and / or from the inside to the outside of the device to absorb and / or absorb hydrogen in the space and release it out of the space. Compared to the OLED device of the bottom emission type, the light efficiency is much higher, and defects such as shrinking of pixels due to moisture and hydrogen can be significantly reduced.

Description

Top-emission type organic light emitting display device

1 is a structural diagram of an organic light emitting display (OLED) device with a conventional technology.

2 to 5 are related to the top-emitting OLED device according to the present invention, which is a cross-sectional view showing the structure of various cases where the hydrogen scavenger is disposed in the interior space of the OLED device.

6 to 8 are related to the top-emitting OLED device according to the present invention, which is a cross-sectional view showing the structure of various cases arranged so that the hydrogen scavenger is connected from the inner space of the OLED device to the outside.

FIG. 9 is a cross-sectional view showing a structure when a hydrogen scavenger is added with a sealant in a mixture with the sealant, as related to the top-emitting OLED device according to the present invention.

* Explanation of symbols for main parts of drawings *

10: substrate 20: organic light emitting unit

22: second electrode layer 23: light emitting organic layer

24: first electrode layer 25: organic light emitting unit

30: transparent dehumidification thin film layer 40: encapsulation layer

50: adhesive film, polarizing film or circular polarizing film

60: mixture of sealant and dehydrogenator

70: sealant 80: hydrogen remover

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to organic light emitting display (OLED) devices, and more particularly to top-emission type OLED devices.

OLED devices are widely used as display devices of various information industrial devices because they have high resolution, high impact resistance, and various colors. The display using the OLED device is relatively much clearer than the liquid crystal display (LCD), the plasma display panel (PDP), and the field emission display (FED), and there is no limitation of the viewing angle, High speed operation is possible and manufacturing cost is low. Therefore, it is attracting attention as a useful display that can be applied to a display of a TV or a computer or a mobile phone, a personal digital assistant (PDA), a computer, a television (TV), and a home appliance.

OLED devices can be largely divided into passive and active. Passive OLED devices have a disadvantage in that the manufacturing process is simple, but the driving voltage is high and the power is consumed a lot, and there is a limit to enlarge the screen. Active OLED devices have the advantages of lower driving voltage, lower power consumption, and medium to large size screens compared to passive devices. 1 shows the structure of a conventional back-emitting active OLED device. An organic light emitting part 5 made of an organic EL material is interposed between the transparent electrode 6 disposed on the TFT layer 7 on the transparent protective layer 8 and the opaque metal electrode 4, and these are formed of an insulating layer ( 3) and an opaque dehumidifying layer 2 is disposed thereon, all of which are surrounded by a front protective layer 1. In the OLED device having such a structure, when a pair of electrodes facing each other, that is, the transparent electrode 6 and the metal electrode 4 supply electrons and holes to the organic light emitting part 5, Holes emit light while binding inside the organic light emitting material layer.

The cross-sectional structure of a conventional back-emitting OLED device is shown in FIG. In the OLED device, a thin film transistor (TFT) 7 is disposed on a substrate, that is, a transparent back protective layer 8, and the organic light emitting part 5 includes a metal electrode 4 and a transparent electrode 6. Sandwiched in between, the transparent electrode 6 is laminated on the TFT layer 7. Since it is a bottom emission type structure, in order to improve light efficiency, a transparent material needs to be positioned on the light traveling path from the organic light emitting part 5 which is a light emitting body to the back surface. However, in the OLED device of FIG. 1, since the TFT layer 7, which is not transparent, is disposed toward the substrate 8 where light is emitted, part of the light emitted from the organic light emitting part 5 is part of the TFT 7. There is a disadvantage in that the light efficiency and aperture ratio fall. The disadvantage that the luminous efficiency is lowered due to the presence of the TFT is that the light generated in the organic light emitting unit 5 is emitted from the opposite side of the substrate 8 on which the TFT 7 is disposed, that is, the front of the OLED element. Top-emission can be effectively overcome.

On the other hand, the OLED device constitutes an electronic circuit element inside the hermetic case and is sealed with an adhesive polymer having low moisture permeability. However, moisture and oxygen can penetrate inside the device during encapsulation and use, and hydrogen can be generated during operation of the device. If the moisture in the OLED device is not removed, problems of performance degradation such as pixel reduction of the OLED device may occur. In addition, if the generated hydrogen is left inside the OLED device, there is a disadvantage that the pressure inside the OLED is increased or the lifetime of the pixel is decreased. Therefore, if the dehumidifying agent and the hydrogen scavenger are placed inside the airtight case of the OLED device, the above problem does not occur. Particularly, in the case of water, the amount of water adsorbed on the accessory and introduced into the OLED element in the encapsulation process should be removed at an early stage. The performance of the dehumidifying agent and the hydrogen remover used in the OLED device is determined by the removal rate, the removal amount and the equilibrium concentration in the equilibrium state. The faster the removal rate and the lower the equilibrium concentration, the better the removal agent.

However, when these dehumidifying agents and hydrogen removing agents are added to the front light emitting OLED device, in order to improve light efficiency, it is necessary to arrange all of these materials to be transparent or not to be transparent so as not to interfere with the light progression.

Regarding a top emitting OLED, US Patent No. 5,739,545 discloses an OLED having a structure in which a transparent electrode is disposed on the front surface to extract light emitted from an organic light emitting layer to the front, but an arrangement and configuration of a dehumidifying agent which is an essential component of the OLED. It is not mentioned. U.S. Patent No. 6,515,428, U.S. Patent No. 6,670,772, U.S. Patent No. 6,608,283 disclose the structure of the thin film transistor, the structure of the electrode, and the like regarding the structure and manufacturing method of the top-emitting active OLED. Etc. are not described. U.S. Patent No. 5,714,838 and U.S. Patent No. 6,420,031 describe a transparent electrode for taking the form of top emission, but do not describe a transparent dehumidifying agent. U.S. Patent Nos. 5,920,080, 6,268,695 and 6,497,598 disclose a method of forming a protective layer by coating a plurality of layers of an insulating material having a low moisture permeability on a transparent electrode. However, there is a problem that the process of forming a plurality of layers of the protective layer is complicated and time-consuming, and the countermeasure against water flowing from the side of the protective layer is insufficient. U.S. Patent No. 6,703,184 discloses a method of using a transparent film having a low moisture permeability and a transparent film for protecting the organic light emitting layer and the electrode. . In fact, the moisture entering after sealing can be blocked among the moisture that may exist inside the OLED, but the moisture adsorbed to the material during the manufacturing process cannot be removed.

Japanese Laid-Open Patent Publication No. 2003-144830 discloses an organometallic compound composed of a Group 3 metal and an organic terminal molecule as a transparent dehumidifying agent used in a top emitting OLED. However, in order to arrange the transparent dehumidifier thin film inside the OLED, there are disadvantages in the process inconvenience that the organic solvent must be used and light is scattered because cracks are easily generated in the formed dehumidifier thin film. Moreover, the baking process which volatilizes a solvent is needed. Process to handle chemical solution and volatilize solvent, which can lead to environmental management problems in the workplace, and smooth surface of transparent dehumidification layer can bring uniform transmittance overall. Do. In addition, there are disadvantages in that the process time is increased due to various processes such as a transparent absorption stock solution combining process, an application process, and a firing process in the OLED manufacturing process. In particular, if the firing process is not perfected, the possibility of progressive dark spots is increased due to outgases such as internal residual solvent.

The object of the present invention is that the light produced by the organic light emitting layer is emitted toward the front side of the substrate on which the TFT (thin film transistor) is disposed, so that no light blocking phenomenon is caused by the TFT, and thus the light efficiency is much higher than that of the conventional back-emitting OLED device. To provide a top-emitting OLED device capable of preventing defects such as shrinking of pixels due to moisture and hydrogen.

According to an aspect of the present invention for achieving the above object, a substrate (substrate) provided with a TFT electrode on the upper surface; A transparent encapsulation layer disposed to face the substrate and spaced apart from each other; A perimeter sealant added along the entire circumference of the edge of the space between the substrate and the encapsulation layer to seal the space; An organic light emitting unit having a structure in which a light emitting organic layer is sandwiched between a first electrode layer and a transparent second electrode layer, and stacked on the TFT electrode such that the second electrode layer faces the encapsulation layer in the space; A transparent dehumidification thin film layer disposed between the second electrode layer and the encapsulation layer to remove moisture in the space; And a hydrogen scavenger disposed in the space and attached to an edge of the space inside the space rather than on an outgoing path from the organic light emitting unit toward the encapsulation layer, the hydrogen scavenger absorbing hydrogen in the space. Top emission organic EL display device (Top Emission OLED) is provided. This arrangement allows the hydrogen scavenger to absorb and remove the hydrogen in the space. Instead of the hydrogen scavenger, a structure including a hydrogen scavenger disposed from the inside to the outside of the space and absorbing hydrogen in the space and releasing it out of the space may be adopted. Arrangement of the hydrogen scavenger so as to be connected from the inside to the outside of the space is specifically, the hydrogen scavenger is coated on the surface of at least one of the substrate and the encapsulation layer, and both edges are left on the coated hydrogen scavenger. In addition, the sealant is added so that the hydrogen scavenger is exposed to the inside and outside of the space. In this arrangement, the hydrogen scavenger absorbs the hydrogen in the space and releases it to the outside for removal.

According to another aspect of the present invention for achieving the above object, a TFT electrode is provided on the upper surface; A transparent encapsulation layer spaced apart from and facing the substrate; A sealant added along the entire circumference of the edge of the space between the substrate and the encapsulation layer to seal the space; A hydrogen scavenger mixed with the sealant and added along the entire circumference of the edge of the space to absorb hydrogen in the space and release it out of the space; An organic light emitting unit having a structure in which a light emitting organic layer is sandwiched between a first electrode layer and a transparent second electrode layer, and stacked on the TFT electrode such that the second electrode layer faces the encapsulation layer in the space; And a transparent dehumidifying thin film layer disposed between the second electrode layer and the encapsulation layer to remove moisture in the space. A hydrogen scavenger may be further added to an edge inside the space that does not interfere with the progress of the optical path from the organic light emitting unit toward the encapsulation layer.

The transparent dehumidifying thin film layer is made of a mixture of a dehumidifying material and a polymer binder that generates hydrogen by decomposing moisture. The dehumidifying material is at least one selected from metals, metal hydrides, alloys or mixtures thereof. The metal is at least one selected from the group consisting of metals having higher ionization tendency than hydrogen or alloys or mixtures thereof. The metal hydride is selected from the group consisting of alkali metal hydrides, alkaline earth metal hydrides, alkali metal hydrides including boron or aluminum, alkaline earth metal hydrides including boron or aluminum, and mixtures thereof. At least one selected.

The hydrogen scavenger is an opaque hydrogen scavenger, a) Nb, Ta, Ti, V, Zr, Pd, PdO; b) alloys or mixtures of Ti and metals selected from Al, Co, Cr, Cu, Fe, La, Mn, Ni, Si, Sn, Y, Zr; c) alloys or mixtures of Zr and metals selected from Al, Co, Cr, Cu, Fe, La, Mn, Ni, Si, Sn, Y, Zr; And d) using at least one selected from the group consisting of a mixture of two or more of the above materials a) to c) alone, or using a mixture of a polymer binder further mixed with an opaque hydrogen remover as described above. I can make it. As the polymer binder, it is preferable to use a thermoplastic resin or a reactive curable resin having a moisture vapor transmission rate (MVTR) of 10 g · mil / m ² · day at 40 ° C. and 75% RH (relative humidity).

Hereinafter, with reference to the accompanying drawings will be described the present invention in more detail.

2 to 5 show various examples of the basic structure of the top-emitting OLED according to the present invention. The structures shown are only different in the location where the hydrogen scavenger 80 is installed. The substrate 10 and the encapsulation layer 40 face each other in parallel and spaced apart from each other, and the entire edge circumference of the space provided between the substrate 10 and the encapsulation layer 40. A perimeter sealant 70 is added along to seal the space. The TFT electrode layer 28 is provided on the upper surface of the substrate 10, and the organic light emitting unit 25 is stacked thereon. The organic light emitting unit 25 has a structure in which the light emitting organic layer 23 is sandwiched between the first electrode layer 24 and the transparent second electrode layer 22. As is well known, the light emitting organic layer 23 is made of a material that emits light by transporting and recombining holes and electrons supplied from the first electrode layer 24 and the second electrode layer 22. The first electrode layer 24 is stacked on the TFT electrode layer 28 so that the second electrode layer 22 faces the encapsulation layer 40. The top emission type structure is a structure in which light generated in the light emitting organic layer 23 is emitted toward the opposite side of the TFT electrode layer 28 (the front side of the device) when voltage is applied to the first electrode layer 24 and the second electrode layer 22. . Therefore, in contrast to the case of the bottom emission method, the light of the light emitting organic layer 23 is emitted toward the front of the substrate 10, that is, through the encapsulation layer 40 and to the outside. Therefore, the elements that are not in the outgoing path, that is, the substrate 10, the TFT electrode layer 28, and the first electrode layer 24 may be opaque, but the elements in the outgoing path, that is, the second electrode layer 22, Encapsulation layer 40, dehumidifying thin film layer 30 and the like should be good light transmission. The first electrode layer 24 may be made of, for example, an opaque metal electrode, and the second electrode layer 22 may be made of, for example, an indium-tin oxide (ITO) electrode.

The substrate 10 may be made of glass, plastic, or the like, and the encapsulation layer 40 cooperates with the substrate 10 to secure the internal space of the OLED device while protecting the elements disposed therein. For example, transparent glass, a transparent polymer film, a transparent plastic, etc. can be used as a material. Of course, glass or plastic may be flexible. Between the encapsulation layer 40 and the organic light emitting unit 25, a polarizing film or circular polarizing film (the polarizing film and the quarter-wave retardation film are bonded to prevent external light from being reflected by the organic light emitting unit 25) Film) (corresponding to reference numeral '50') may be added.

Dehumidifiers need to be placed in the space to remove moisture that has penetrated the internal space of the OLED device. To this end, a dehumidifying thin film layer 30 is added between the second electrode layer 22 and the encapsulation layer 40 of the organic light emitting unit 25. Light generated in the organic light emitting unit 25 is emitted through the encapsulation layer 40. The dehumidifying thin film layer 30 is preferably disposed on the light exit path because it is preferably disposed in the inner space for effective moisture removal. Therefore, the dehumidification thin film layer 30 should be transparent. In addition, substances that remove moisture include substances that remove moisture by absorbing moisture (moisture absorption type dehumidifiers) and substances that have the function of removing moisture by generating hydrogen by decomposing moisture (moisture decomposition type dehumidifiers). have. Moisture decomposition type dehumidifying agent has better water removal performance than water absorption type dehumidifying agent and thus has high efficiency of preventing pixel reduction phenomenon. Therefore, either material may be used as a raw material of the dehumidifying thin film layer 30, but it is more preferable to use a water-decomposable dehumidifying agent having better water removal efficiency.

Representative examples of water-decomposable dehumidifying materials include metals, metal hydrides, alloys or mixtures thereof, and the like. Usable metals are metals having higher ionization tendency than hydrogen or alloys or mixtures thereof, and specific examples thereof include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and beryllium (Be). ), Magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), aluminum (Al), zinc (Zn), iron (Fe), nickel (Ni), and the like. The metal hydride is selected from the group consisting of alkali metal hydrides, alkaline earth metal hydrides, alkali metal hydrides including boron or aluminum, alkaline earth metal hydrides including boron or aluminum, and mixtures thereof. It is preferred that it is at least one selected. Examples of such metal hydrides include sodium hydride (NaH), potassium hydride (KH), calcium hydride (CaH ₂ ), strontium hydride (SrH ₂ ), aluminum hydride (AlH ₃ ), and lithium borohydride. Hydride (LiBH ₄ ), lithium aluminum hydride (LiAlH ₄ ), sodium aluminum hydride (NaAlH ₄ ), potassium aluminum hydride (KAlH ₄ ), calcium aluminum hydride (CaAl ₂ H ₈ ), and the like. In the case of the dehumidifying material using the metal hydride, water is removed by the following scheme 3.

Scheme 3

MH _n + nH ₂ O → M (OH) _n + nH ₂

Dehumidifying thin film can be made by adding water-decomposable dehumidifying material as a main raw material and adding water-absorbing dehumidifying material such as alkali metal oxide and alkaline earth metal oxide. In order to improve transparency, the dehumidifying material preferably has a particle size of 1 micron or less, and excellent transparency is obtained when dispersed or dissolved in a polymer binder with a size of about 50 nanometers or less. In addition, even when the refractive index of the dehumidifying material and the polymer binder is similar, transparency is obtained well.

The transparent dehumidifying material, which is a raw material of the transparent dehumidifying thin film layer 30, should have good dehumidification performance, be easily formed into a film form, have a transparent characteristic after film forming, and be easily bonded to a circularly polarized film. Since the mixture containing the dehumidifying material and the thermoplastic resin or the mixture containing the dehumidifying material and the reaction hardening resin satisfies these characteristics well, the transparent dehumidifying thin film 30 is made using this mixture. Polymer binders such as thermoplastic resins or reactive curable resins preferably have a polymer having a high MVTR because the light transmittance decreases when the polymer binder is made porous to facilitate mass transfer. In addition, it is desirable to minimize turbidity in order to minimize the decrease in transmittance due to light scattering. Furthermore, the dehumidifying material preferably has a property that can be attached to another object (eg, the polarizing film 50) by heat pressing without a separate adhesive.

In order to reduce the turbidity of the mixture of the dehumidifying material and the polymer binder, it is preferable that the polymer binder such as the dehumidifying material and the thermoplastic resin or the reactive curing resin have the following characteristics.

(1) the particle size of the dehumidifying material is sufficiently smaller than the wavelength of visible light (usually 50 nanometers or less) so that it is in the Rayleigh scattering range, or

(2) Since the refractive index of the dehumidifying material and the polymer binder is similar, it is preferable that the value of Rayleigh ratio (R (theta)) defined by Equation 1 below is small. In other words,

Here, n ₀ is a refractive index of the thermoplastic or reactive curable resin, and has a specific range of values inherent to each material, and c is a concentration of the dehumidifying material but cannot be lowered below a certain concentration in consideration of the water removal efficiency of the transparent dehumidifying agent. In addition, λ has a constant value because it is the wavelength of visible light, M and N _A is also a constant value because the molecular weight and avogadro number of the dehumidifying material, respectively. Therefore, a way to lower the Rayleigh ratio is to make the value ' dn / dc ' small. ' dn / dc ' is the amount of change in the refractive index of the mixture of the dehumidifying material and the polymer binder according to the concentration change.

MVTR may vary somewhat depending on the processing method of the transparent dehumidifying thin film 30, but is a physical property depending on the chemical structure of the polymer binder. Therefore, MVTR is a property that can be used as a selection criteria of the polymer binder used as a mixed material with the dehumidifying material in the present invention. As a material that can be used as the polymer binder, a thermoplastic resin or a reactive curable resin having a water transmittance (MVTR) of 40 ° C. and 75% RH (relative humidity) of 10 g · mil / m ² · day or more is preferable. Representative examples of thermoplastic resins satisfying these characteristics include polyolefins, unsaturated polyolefins, substituted polyolefins, substituted unsaturated polyolefins and random copolymers or block copolymers of monomers thereof. The polyolefin may be selected from polyethylene, polypropylene, polybutene, poly (4-methylpentene) or mixtures thereof. The unsaturated polyolefin may be selected from polybutadiene, polyisoprene or mixtures thereof. Substituted polyolefins can be selected from polystyrene, polyvinylchloride, polyvinylfluoride, polyvinylidenechloride, polyvinylidenefluoride or mixtures thereof. Substituted unsaturated polyolefins include polychloroprene. Still other examples of thermoplastic resins include polyphenylene oxide, polyphenylene sulfide, polyethersulfone or mixtures thereof. In addition, examples of the reaction curable resin that satisfies the above water-permeability characteristics include a polymerizable resin. The polymerizable resin may be one in which the polymerization reaction is initiated by radiation energy or one may be initiated by heat.

The transparent dehumidifying thin film layer 30 may be directly attached to the encapsulation layer 40 by utilizing a self-adhesive force of the polymer binder or by using a pressure sensitive adhesive or a pressure sensitive adhesive. Alternatively, as shown, the transparent dehumidifying thin film layer 30 may be attached to the encapsulation layer 40 by applying it to a film 50 such as an adhesive film or a polarizing film. The organic light emitting unit 25 is disposed to be spaced apart from the transparent dehumidifying thin film layer 30 and the encapsulation layer 40 or to be insulated from each other through an insulating material.

On the other hand, if the hydrogen generated in the OLED element is left, the pressure inside the OLED element rises or the lifetime of the pixel decreases. In order to prevent such a problem, it is preferable to further dispose a hydrogen scavenger in the internal space of the OLED element to absorb hydrogen to reduce the hydrogen concentration in the space. However, it is difficult to make the hydrogen scavenger transparent, and in order to prevent the light efficiency from deteriorating due to the arrangement of the hydrogen scavenger, the hydrogen scavenger does not need to be disposed outside the light path from the organic light emitting unit 25 to the encapsulation layer 40. have. The location in the OLED device space that does not interfere with the light output is the edge inside the space. Specifically, suitable locations where the hydrogen scavenger 80 can be installed include: i) on the inner wall of the substrate 10 between the organic light emitting unit 25 and the sealant 70 in the space ( 2), ii) on the inner wall of the encapsulation layer 40 between the transparent dehumidifying thin film layer 30 and the sealant 70 in the space of the OLED device (see FIG. 3), iii) the organic light emitting unit 25 At the edge of the transparent dehumidifying thin film layer 30 that does not overlap (see FIG. 4), iv) at the edge of the organic light emitting unit 25 that does not overlap the transparent dehumidifying thin film layer 30 (see FIG. 5), and v) i) to iv) mixed position. In arranging the hydrogen scavenger 80, it is preferable to arrange the hydrogen scavenger 80 in a thin stripe or a line along a part or all of the edge circumference so as to occupy the narrowest possible area.

The hydrogen scavenger 80 is made using an opaque hydrogen removal material or a mixture of opaque hydrogen removal material and polymer binder. Examples of opaque dehydrogenates include: a) Nb, Ta, Ti, V, Zr, Pd, PdO; b) alloys or mixtures of Ti and metals selected from Al, Co, Cr, Cu, Fe, La, Mn, Ni, Si, Sn, Y, Zr; c) alloys or mixtures of Zr and metals selected from Al, Co, Cr, Cu, Fe, La, Mn, Ni, Si, Sn, Y, Zr; And d) a mixture of two or more of the materials of a) to c) above. The polymer binder used in the manufacture of the transparent dehumidifying thin film 30 may also be used as a polyminder for producing the hydrogen removing agent 80. The hydrogen scavenger 80 may be attached to the position using a pressure sensitive adhesive or a pressure sensitive adhesive.

On the other hand, the amount of hydrogen removed may be greater if the hydrogen generated in the internal space of the OLED device can be released to the outside as well. Considering this point, a modified structure of the top-emitting OLED is shown in FIGS. 6 to 8. 2 to 5 is different from the arrangement of the hydrogen scavenger, wherein the hydrogen scavenger 80 is arranged to be connected from the inside to the outside of the space of the OLED element. Specifically, according to one example shown in FIG. 6, the hydrogen scavenger 80 is coated on its surface along the entire circumference of the edge of the substrate 10, and the coated hydrogen scavenger 80 and the encapsulation layer ( A sealant 70 is added between 40. At this time, in order for the hydrogen scavenger 80 to be disposed so as to be connected from the inside to the outside of the space of the OLED element, the sealant 70 does not cover the entirety of the hydrogen scavenger 80 and both edge portions thereof are the inner space of the OLED element. Are added to and respectively exposed to the outside. The dehydrating agent 80 may be coated on the encapsulation layer 40 as in the example shown in FIG. 7, or may be coated on both the substrate 10 and the encapsulation layer 40 as illustrated in FIG. 8. have. When the hydrogen scavenger 80 is disposed in this form, the hydrogen scavenger 80 absorbs the hydrogen present in the space of the OLED element, while the hydrogen concentration contained in the hydrogen scavenger 80 and the hydrogen concentration outside the OLED element. There is a large difference between the two, and because of the difference in concentration, the hydrogen contained in the hydrogen removing agent 80 is also released out of space. Coating of the hydrogen removing agent on the substrate 10 or the encapsulation layer 80 can be performed by sputtering or the like.

9 shows another variant of the top emitting OLED. The difference from the structure of the OLED device described above is that the mixture between the hydrogen scavenger and the sealant is mixed to seal the space between the substrate 10 and the encapsulation layer 80. Since the hydrogen scavenger is exposed to both the interior space and the exterior of the OLED device, the hydrogen absorber absorbs the hydrogen present in the interior space of the OLED device and releases it out of the space as in the structure just described. A mixture of such a structure and the structure illustrated in FIGS. 2 to 5 mentioned above can be mixed, and a hydrogen scavenger can be added to the sealant at the same time and added to the edge inside the space of the OLED element.

On the other hand, depending on the manufacturing process of the OLED element, a small amount of oxygen may be initially added depending on the necessity of the process, and the added oxygen may be removed after a certain time has elapsed. When oxygen addition is required in the process, the oxygen removing material may be mixed with the transparent dehumidifying thin film layer 30 and / or the opaque hydrogen removing agent 80. Metal oxygen is used as the oxygen removing material.

The plurality of electrodes of the transparent second electrode layer 22 are insulated from each other. In this state, when the transparent dehumidification thin film layer 30 is laminated on the transparent second electrode layer 22 in a direct contact form, moisture or the like contained in the transparent dehumidification thin film layer 30 is insulated between the electrodes of the second electrode layer 22. Can cause problems, and in extreme cases can cause short circuits between the electrodes. In order to prevent such a short circuit between the transparent electrodes, the organic light emitting unit 25 is preferably insulated from the transparent dehumidifying thin film layer 30. For this insulation, an insulating material may be filled between the organic light emitting unit 25 and the transparent dehumidifying thin film layer 30. Since the insulating material has a very high electrical resistance and is present on the light emission path, it is preferable to have excellent light transmittance, and may be a material in any state of a solid, liquid, or gas. In the case of gas, argon gas or nitrogen gas, in case of liquid, silicon oil, and in case of solid, polymer or glass material can be used as an insulating material.

Next, embodiments of the present invention will be described.

(1) fabrication and evaluation of transparent dehumidifying thin films

1) Fabrication of transparent dehumidifying thin film

Work was performed in a glove box managed at a concentration of 1 to 2 ppm, and three samples were prepared by the following formulation.

Dehumidification Sample Dehumidifier Polymer binder One Lithium borohydride (LiBH ₄ )-2 g Polystyrene-50 g 2 Sodium Hydride (NaH)-2 g Polystyrene-polyisoprene block co-polymer-50 g 3 Zn (Zinc, Zinc, Particle Size = 100nm)-5g Poly (methylstyrene)-50 g

Preparation of the sample was carried out in the following order. First, a dehumidifying material was added above the melting point of the polymer binder, and then mixed well with a homogenizer. The molten state was thinly spread on a release film and cooled to form a film having a solid thickness of about 1 mm in a mixture of a dehumidifying substance and a polymer binder. In order to make the thin film of the mixture film of 1mm dehumidifying material and polymer binder thus made, it was pressed by passing between two heated rollers while sandwiching between two release films. This made a dehumidifying film that was transparent and was as thin as 50 microns.

2) Light transmittance evaluation of the transparent dehumidifying film

The result of measuring the light transmittance of the transparent dehumidifying film produced as above is as follows.

Light transmittance Transparent Dehumidification Film 460 nm 540 nm 680 nm One 83% 86% 87% 2 65% 70% 73% 3 71% 73% 76%

(2) Preparation of hydrogen remover

Samples were prepared by the following formulation.

Hydrogen Remover Hydrogen Remover Polymer Binder One Zr-6.5 g Ni-3.6 g Ce-0.4 g Poly (styrene-methylstyrene)-5 g 2 Pd-10 g Polystyrene-polyisoprene block co-polymer-5 g

Particles of the hydrogen removal material was selected to have a size of 10 ~ 50micron. The polymer binder is heated and melted, and then the hydrogen removal material is mixed, cooled, and then hardened.

(3) Assembly and functional evaluation

1) Fabrication of OLED Sample

The assembly of the OLED sample was produced by five for each condition using the structure as shown in FIG. The OLED element used was one having a width of 25 mm and a height of 20 mm. The assembly work of the OLED sample was performed in a glove box in which water was kept at 2 ppm or less and oxygen was 1 ppm or less. The pressure of the glove box at the time of assembly maintained the atmospheric pressure (760 +/- 5 mmHg). The thickness of the transparent moisture-dehumidifying thin film layer was 50 microns, and the hydrogen scavenger was prepared in a strip shape having a thickness of 50 microns of 1 mm and disposed at the edges of three sides of the OLED.

The produced OLED sample is as follows.

sample Transparent Dehumidifying Film Hydrogen Remover 1 (Example 1) One One 2 (Example 2) 2 2 3 (comparative example 2) One Do not use 4 (comparative example 2) Do not use Do not use

2) Evaluation method

After leaving the four OLED samples manufactured at the humidity of 90% and the temperature of 65 ℃ for 360 hours, the reduction of pixel size and the increase of pressure in the internal space due to hydrogen generation are observed. Observed.

3) Evaluation result

The measurement results for the pixel reduction width of the edge of the OLED sample and the pressure increase in the internal space are as follows.

sample Pixel reduction width of edge Pressure increase inside OLED sample 1 (Example 1) 3.8micron -17mmHg 2 (Example 2) 2.7micron -8mmHg 3 (comparative example 1) 3.2micron + 760mmHg or more 4 (comparative example 2) 22.7micron + 63mmHg

As shown in the above results, when using a transparent dehumidifying film and a hydrogen remover at the same time (Examples 1 and 2), the light transmittance of the transparent dehumidifying film is approximately 70% or more can be evaluated as sufficient, and the water removal effect In addition, the pixel reduction width at high temperature / high humidity is not so large, and the pressure inside the OLED sample is also reduced due to the effective action of the hydrogen scavenger, resulting in greatly improved device stability.

In contrast, the sample using only the transparent dehumidifying film without the hydrogen scavenger in the OLED device (Comparative Example 1) increased the pressure beyond the measuring range (760 mmHg) of the measuring instrument due to the hydrogen generated during the decomposition of moisture in the dehumidifying film. The stability of the sample was significantly lowered, and one of the five samples tested was also broken by an increase in pressure. When neither the transparent dehumidification film nor the hydrogen scavenger was used (Comparative Example 2), the degree of pixel reduction was remarkable and the pressure of the OLED device was also significantly increased.

In view of the above evaluation results, it can be seen that the simultaneous use of the transparent dehumidifying film and the hydrogen scavenger minimizes the pixel reduction of the device and lowers the device pressure, which is very advantageous in terms of device performance and lifespan.

The OLED device according to the present invention takes the form of front light emission, so that light blocking by TFT (thin film transistor) does not occur, and thus the light efficiency is much higher than that of the conventional OLED device of the back light emission type. In addition, by separating the dehumidifying material that can be produced with a transparent thin film and the hydrogen removing material that cannot be made transparent, the transparent dehumidifying thin film is placed in a position where light transmits to remove a large amount of water, an opaque hydrogen removing agent Is arranged in the shape of a line at the edge of the OLED device, and does not obstruct the direction of light and can remove a large amount of hydrogen.

Claims (28)

A substrate on which a TFT electrode is provided; A transparent encapsulation layer disposed to face the substrate and spaced apart from each other; A perimeter sealant added along the entire circumference of the edge of the space between the substrate and the encapsulation layer to seal the space; An organic light emitting unit having a structure in which a light emitting organic layer is sandwiched between a first electrode layer and a transparent second electrode layer, and stacked on the TFT electrode such that the second electrode layer faces the encapsulation layer in the space; A transparent dehumidification thin film layer disposed between the second electrode layer and the encapsulation layer to remove moisture in the space; And Located in the space but attached to the edge of the interior of the space rather than on the outgoing path from the organic light emitting unit toward the encapsulation layer, comprising a hydrogen scavenger that absorbs hydrogen in the space at least Top emission OLED display device. A substrate on which a TFT electrode is provided; A transparent encapsulation layer disposed to face the substrate and spaced apart from each other; A perimeter sealant added along the entire circumference of the edge of the space between the substrate and the encapsulation layer to seal the space; An organic light emitting unit having a structure in which a light emitting organic layer is sandwiched between a first electrode layer and a transparent second electrode layer, and stacked on the TFT electrode such that the second electrode layer faces the encapsulation layer in the space; A transparent dehumidification thin film layer disposed between the second electrode layer and the encapsulation layer to remove moisture in the space; And And a hydrogen scavenger disposed to be connected from the inside to the outside of the space and absorbing the hydrogen in the space to release the outside of the space. 2. The edge of the space within which the hydrogen scavenger is disposed is i) an inner wall of the encapsulation layer between the transparent dehumidifying thin film layer and the sealant in the space, ii) the organic light emitting in the space. An inner wall of the substrate between the unit and the sealant; An organic light emitting display device, characterized in that the front emission type. The front light emitting organic EL display device according to any one of claims 1 to 3, wherein the transparent dehumidifying thin film layer is attached to a corresponding position using a pressure sensitive adhesive or a pressure sensitive adhesive. 3. The hydrogen scavenger according to claim 2, wherein the hydrogen scavenger is opaque, coated on at least one surface of the substrate and the encapsulation layer, and the sealant is added to the hydrogen scavenger leaving both edges above the coated hydrogen scavenger. The front emission type organic EL display device, characterized in that both ends are disposed in a form that is exposed to the inside and outside of the space, respectively. 6. The light emitting organic EL display device according to claim 5, wherein the hydrogen scavenger is coated by sputtering. A substrate on which a TFT electrode is provided; A transparent encapsulation layer spaced apart from and facing the substrate; A sealant added along the entire circumference of the edge of the space between the substrate and the encapsulation layer to seal the space; A hydrogen scavenger mixed with the sealant and added along the entire circumference of the edge of the space to absorb hydrogen in the space and release it out of the space; An organic light emitting unit having a structure in which a light emitting organic layer is sandwiched between a first electrode layer and a transparent second electrode layer, and stacked on the TFT electrode such that the second electrode layer faces the encapsulation layer in the space; And And at least a transparent dehumidification thin film layer disposed between the second electrode layer and the encapsulation layer to remove moisture in the space. 8. The front light-emitting device as claimed in claim 7, wherein a hydrogen scavenger for absorbing and removing hydrogen is further added to an edge inside the space that does not interfere with the progress of the optical path from the organic light emitting unit toward the encapsulation layer. Type organic EL display element. The front light emitting organic EL display device according to claim 1 or 2, wherein the transparent dehumidifying thin film layer is made of a mixture of a dehumidifying material that generates hydrogen by decomposing moisture and a polymer binder. 10. The OLED display device of claim 9, wherein the dehumidifying material is at least one selected from metal, metal hydrides, alloys and mixtures thereof.        The front-emitting organic EL display device according to claim 10, wherein the metal is at least one selected from the group consisting of metals having higher ionization tendency than hydrogen, alloys or mixtures thereof. The method of claim 10, wherein the metal is lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), aluminum (Al), zinc (Zn), iron (Fe), nickel (Ni) at least one selected from the group consisting of a top-emitting organic EL display device. The metal hydride of claim 10, wherein the metal hydride is an alkali metal hydride, an alkaline earth metal hydride, an alkali metal hydride including boron or aluminum, an alkaline earth metal hydride including boron or aluminum, and At least one selected from the group consisting of a mixture thereof. 12. The top emitting organic EL display device according to claim 11, wherein the metal or the metal hydride has a particle size of 1 micron or less. The front light emitting organic EL display device according to claim 11, wherein the metal or the metal hydride has a particle size of 50 nanometers or less. The front light emitting organic EL display device according to any one of claims 1, 2 and 7, wherein the organic light emitting unit is insulated from the transparent dehumidifying thin film layer. The method according to any one of claims 1, 2 and 7, further comprising an oxygen scavenger of a metal material mixed with at least one of the transparent dehumidifying thin film layer and the hydrogen scavenger to remove oxygen in the space. Full-emitting organic EL display device. The method according to any one of claims 1, 2, 7, 8, wherein the hydrogen scavenger is an opaque hydrogen scavenger, a) Nb, Ta, Ti, V, Zr, Pd, PdO; b) alloys or mixtures of Ti and metals selected from Al, Co, Cr, Cu, Fe, La, Mn, Ni, Si, Sn, Y, Zr; c) alloys or mixtures of Zr and metals selected from Al, Co, Cr, Cu, Fe, La, Mn, Ni, Si, Sn, Y, Zr; And d) at least one selected from the group consisting of a mixture of two or more materials from the above materials a) to c). 19. The front light emitting organic EL display device according to claim 18, wherein the hydrogen scavenger is a mixture of a polymer binder further mixed with the opaque hydrogen scavenger. 10. The front light-emitting of claim 9, wherein the polymer binder is a thermoplastic resin or a reactive curable resin having a water transmittance (MVTR) of at least 10 g · mil / m ² · day at 40 ° C. and 75% RH (relative humidity). Type organic EL display element. The random copolymer of claim 20, wherein the thermoplastic resin is selected from the group consisting of i) polyolefins, ii) unsaturated polyolefins, iii) substituted polyolefins, iv) substituted unsaturated polyolefins, v) polyolefins, unsaturated polyolefins, monomers of substituted polyolefins. Polymer, vi) polyphenylene oxide, Vii) polyphenylene sulfide, viii) polyether sulfone, ix) polyphenylene oxide, polyphenylene sulfide, polyether sulfone Emission type organic EL display device. The front emission type organic EL display device according to any one of claims 1 to 3, wherein the hydrogen scavenger is attached to a corresponding position using a pressure sensitive adhesive or a pressure sensitive adhesive. 20. The front light-emitting device as claimed in claim 19, wherein the polymer binder is a thermoplastic resin or a reactive curable resin having a moisture permeability (MVTR) of 40 g at 75% RH (relative humidity) of 10 g · mil / m ² · day or more. Type organic EL display element. 24. The method of claim 23, wherein the thermoplastic resin is a random copolymer or block copolymer of monomers of i) polyolefins, ii) unsaturated polyolefins, iii) substituted polyolefins, iv) substituted unsaturated polyolefins, v) polyolefins, unsaturated polyolefins, substituted polyolefins. Polymer, vi) polyphenylene oxide, Vii) polyphenylene sulfide, viii) polyether sulfone, ix) polyphenylene oxide, polyphenylene sulfide, polyether sulfone Emission type organic EL display device. The front light emitting organic EL display device according to claim 23, wherein the reaction curable resin is a polymerizable resin. The front light emitting organic EL display device according to claim 25, wherein the polymerizable resin is one in which a polymerization reaction is initiated by radiation energy or a polymerization is initiated by heat. The front light emitting organic EL display device according to claim 20, wherein the reactive curable resin is a polymerizable resin. The front light emitting organic EL display device according to claim 27, wherein the polymerizable resin is one in which a polymerization reaction is initiated by radiant energy or a heat is initiated.

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