KR100595167B1 - organic electroluminescence device with organic coating layer for preventing penetration of moisture - Google Patents

Abstract

The present invention is a substrate; A stack structure consisting of a first electrode, a second electrode, and a plurality of organic films; And a cover plate formed at regular intervals on the laminated structure to surround the laminated structure as a whole, wherein the organic coating layer is formed on the outer surface of the organic light emitting element to prevent moisture penetration. A polymer compound having a hydrophobic group, comprising an organic electroluminescent device characterized in that formed of a material selected from any one of polyethylene, polyethylene derivatives, polypropylene or polypropylene derivatives, to prevent the penetration of moisture into the device It can extend the life. In this case, the organic coating layer may be locally or entirely formed on the outer surface of the organic light emitting diode.

Moisture penetration

Description

Organic electroluminescence device with organic coating layer for preventing penetration of moisture}

1 is a diagram showing an embodiment of the present invention;

2 is a view showing another embodiment of the present invention.

<Description of Major Symbols in Drawing>

1: Substrate 13: Support Layer

3: first electrode 15: moisture absorbent layer

5: multiple organic laminate 17: cover plate

7: second electrode 19: organic coating film for preventing moisture penetration

9: protective film 21: adhesive

11: nitrogen gas

The present invention relates to an organic light emitting device, and more particularly, to an organic light emitting device in which an organic coating film for preventing moisture penetration is formed.

Recently, as the size of a display increases, the demand for a display device having less space is increasing. One such display element is an electroluminescent element. The electroluminescent device is classified into an inorganic electroluminescent device and an organic electroluminescent device according to the material used.

In general, an inorganic electroluminescent device is a device that accelerates electrons by applying a high electric field so that the accelerated electrons collide with the emission center and the emission center is excited to emit light.

The organic light emitting device injects electrons and holes from the electron injection electrode (cathode) and the hole injection electrode (anode) into the light emitting unit, respectively, and excitons generated by the combination of electrons and holes are based on the excited state. The device emits light when it falls to the ground state.

Such organic electroluminescent devices not only form devices on flexible transparent substrates such as plastics, but also have excellent characteristics such as wide viewing angle, high-speed response and high contrast, so that they can be used for graphic displays or surfaces. It can be used as a pixel of a surface light source, can be driven at a lower voltage (10V or less) than a plasma display panel or an inorganic light emitting device, and consumes relatively little power, green, It can display three colors of blue and red, and is suitable for next-generation flat panel display.

The organic electroluminescent device has superior characteristics compared to the inorganic electroluminescent device, but has been a big problem in practical use was short life. Important factors for shortening the life of the device may be impurities in the organic material, an interface between the organic material and the electrode, a low crystallization temperature (Tg) of the organic material, and oxidation of the device by oxygen and moisture.

Impurities in the organic material may trap electrons, holes, or the like, or leak current, and the life of the device may be shortened when the crystallization of the organic material is increased. In addition, when the interface between the electrode and the organic material is not good, it is difficult to inject charges and holes, and a large amount of current may flow to damage the organic material, and the low crystallization organic material is crystallized and excited inside the device. Molecules do not emit energy as light, but transition to non-luminescence (vibration and rotation) energy levels, reducing luminous efficiency and shortening lifetime.

In order to solve this problem, the purification of organic materials, the development of a material having a high crystallization temperature (Tg), and the introduction of a material for increasing adhesion between the organic material and the electrode have been studied and brought about a lot of developments. In addition, one of the factors that greatly affect the life of the device is the shrinkage of the light emitting area due to the penetration of oxygen and moisture.

Moisture and oxygen, which reduce the light emitting area of the device, are largely possible to penetrate from the inside and the outside already in the process of making the device, and various methods have been proposed to solve this problem.

In Japanese Patent Laid-Open No. 9-148066, an adsorbent such as a metal oxide, an alkali metal oxide, an alkaline earth metal oxide, a sulfate or a metal halide compound is coated on a cover plate by a method such as vacuum deposition, sputtering or spin coating. The cover plate was adhered to the substrate using an adhesive. An epoxy resin was used as an adhesive agent.

However, epoxy resins basically contain hydrophilic groups to provide adhesion to the substrate and the glass surface, and these hydrophilic groups remain on the surface after curing. The hydrophilic nature of these surfaces leads to the adsorption of moisture, which in turn facilitates the penetration of moisture into the device.

In order to solve the above-mentioned problems, the present invention forms an organic coating film for preventing moisture penetration in the organic light emitting device to prevent moisture from penetrating into the inside of the organic light emitting device having an extended lifetime and improved luminous efficiency. The purpose is to provide.

The present invention is a substrate; A stack structure consisting of a first electrode, a second electrode, and a plurality of organic films; And a cover plate formed at regular intervals on the laminated structure to surround the laminated structure as a whole, wherein the organic coating layer for preventing moisture penetration is formed on an outer surface of the organic light emitting diode. An organic electroluminescent device is provided. In this case, the organic coating layer may be formed locally on the site where the hydrophilic group compound is exposed on the outer surface of the organic light emitting device, or may be formed on the entire outer surface of the organic light emitting device.

The site in which the hydrophilic group compound is present may include a site for adhering the substrate and the cover plate, and the entire outer surface of the organic light emitting device is a cover plate formed on the organic light emitting device, and a part for adhering the substrate and the cover plate. It may include.

In the organic light emitting device according to the present invention, the organic coating layer for preventing moisture penetration may be made of a polymer compound, wherein the polymer compound preferably has a hydrophobic group. The hydrophobic polymer compound may be selected from polyethylene, polyethylene derivatives, polypropylene or polypropylene derivatives. In addition, the polyethylene derivative and the polypropylene derivative preferably include a halogen group.

The organic coating film material is more preferably polytetrafluoroethylene, polytrifluoroethylene, polydifluoroethylene, polyfluoroethylene, polytetrachloroethylene, polytrichloroethylene, polydichloroethylene and polychloroethylene It is formed of a material selected from.

According to the present invention, an organic electroluminescent device having an organic coating film for preventing moisture penetration is provided with a substrate; A first electrode formed on the substrate; A plurality of organic laminated films formed on the first electrodes; Second electrodes formed on the plurality of organic stacked films; A protective film formed on the second electrode and made of an organometallic compound or a polymer compound; A cover plate formed at regular intervals on the stack structure so as to surround the stack structure of the first electrode, the plurality of organic stacked films, the second electrode, and the protective film as a whole, and bonded to the substrate by an epoxy compound; And polytetrafluoroethylene, polytrifluoroethylene, polydifluoroethylene, polyfluoroethylene, polytetrachloroethylene, polytrichloroethylene, polydichloro on the outer surface of the cover plate and the exposed surface of the epoxy compound. It is characterized in that the organic coating layer for preventing moisture permeation, which is made of a material selected from ethylene and polychloroethylene, is an organic light emitting device that is formed locally or entirely.

In this case, the lower surface of the cover plate may further include an absorbent layer, and when the absorbent layer is formed, the support layer may be further included on the lower surface.

The structure of the organic light emitting device to which the organic coating film for preventing moisture permeation of the present invention can be applied may be borrowed from the prior art. A plurality of organic laminated films included in the organic light emitting device may be formed of a hole injection layer, a hole transport layer, an organic light emitting layer, an electron transport layer and an electron injection layer as described in the prior art, a part of which may be omitted The materials used in each layer may also be selected and used in the prior art. For example, an alloy of aluminum (Al) or magnesium: silver (Mg: Ag) is used as a material of the second electrode layer of the organic light emitting diode, and may be formed to a thickness of about 50 nm.

In the organic light emitting device according to the present invention, a protective film made of an organic metal compound or a polymer compound may be formed on the second electrode through a process such as chemical vapor deposition (CVD), but the protective film may be omitted if necessary. Can be.

The cover plate prevents penetration of moisture and oxygen, and materials used include glass, plastic, and coated metal plates. The cover plate is formed to surround the entire laminated structure formed through a plurality of organic layers on the substrate. do. The plastic can be used in a limited range depending on the thickness, but is usually poly (ethylene terephthalate) (PET), poly (butylene terephthalate) [poly (butylene terephthalate): PBT] Nylon, polycarbonate (PC), and the like may be used.

The cover plate formed of the above materials can be made concave so that the moisture absorbent layer can be introduced. As the moisture absorbent layer, various compounds suitable for the purpose of absorbing moisture may be used.

The cover plate is formed at a predetermined interval on top of the laminated film structure formed on the substrate is bonded to the substrate. In this case, the cover plate may be formed to completely surround the laminated film structure, and the cover plate and the substrate may be bonded using a material such as an epoxy resin.

The epoxy resin includes a hydrophilic group to have an adhesive force to the substrate and the glass surface. This hydrophilic property remains on the surface even after the epoxy resin is cured. Accordingly, moisture can be easily adsorbed onto the adhesive surface and can penetrate into the device along the minute gaps of the epoxy resin surface. Therefore, an organic coating film for preventing moisture penetration is formed on the outer surface of the completed organic electroluminescent device, and the area where the organic coating film is formed is a part where the hydrophilic group compound is exposed to the outside, for example, a substrate and a cover. The site | part which adhere | attaches a plate includes the site | part in which compounds, such as an epoxy resin, are exposed to the exterior of an element.

A polymer compound may be used as the material used for the moisture-permeable organic coating layer, and the polymer compound preferably has a hydrophobic group to prevent the adsorption of water by making the surface of the epoxy resin a hydrophobic compound. As the polymer compound having a hydrophobic group, polyethylene, polyethylene derivatives, polypropylene, polypropylene derivatives, and the like may be selected, and the derivatives preferably include a halogen group. As the material used for the organic coating membrane for preventing moisture penetration of the present invention, polytetrafluoroethylene, polytrifluoroethylene, polydifluoroethylene, polyfluoroethylene, polytetrachloroethylene, polytrichloroethylene, Polydichloroethylene, polychloroethylene and the like are selected.

As a method of coating a hydrophobic polymer material on the organic light emitting device, a method of forming an organic coating film by dissolving the hydrophobic polymer in a solvent by dipping, spraying, etc. on the outer surface of the device. One example is a method of dissolving polytetrafluoroethylene, a hydrophobic polymer, in n-butylacetate, a solvent, and dipping the organic electroluminescent device in this solution. After the dipping process, the solvent is easily evaporated and fly away within a short time, leaving only the polymer to change the exterior of the cover plate from hydrophilic to hydrophobic.

(Example 1)

A schematic cross-sectional view of an organic light emitting display device in which an organic coating film, which is an embodiment of the present invention, is formed on an entire outer surface of a device is illustrated in FIG. 1, and a detailed description thereof is as follows.

The first electrode 3, the plurality of organic stacked layers 5, the second electrodes 7, and the passivation layer 9 are sequentially formed on the substrate 1, and the cover plate is spaced apart from the passivation layer 9 at an interval. (17) was formed to block moisture and oxygen. The cover plate 17 may be formed with a recessed groove in a lower side of the laminated film structure to introduce the moisture absorbent layer 15. In addition, the support layer 13 is introduced below the moisture absorbent layer 15 to prevent the material of the moisture absorbent layer 15 from falling toward the laminated film structure, thereby improving the life of the device and maintaining the luminous efficiency of the device. have. The protective film 9 formed on the second electrode 7 can be omitted in the above structure.

As such, when the cover plate 17 having the moisture absorbent layer 15 and the support layer 13 introduced thereon is adhered to the substrate 1, an epoxy resin adhesive 21 may be used. At this time, the space 11 formed between the cover plate 17 and the laminated film structure is filled with an inert gas such as nitrogen gas (N ₂ ).

Finally, the organic coating layer 19 for preventing moisture penetration is formed on the entire outer surface of the organic light emitting device including the exposed surface of the epoxy resin adhesive 21 and the outer surface of the cover plate 15. The constituent components of the organic coating film that can be used and their functions are described above.

(Example 2)

As another embodiment of the present invention, there is shown a schematic cross-sectional view of an organic light emitting display device in which the organic coating layer for preventing moisture penetration is formed only on a part of the surface including a portion for adhering the cover plate and the substrate, not the entire external surface of the organic light emitting device. 2 is shown. Except for the above difference, the organic light emitting display device shown in FIG. 1 is the same.

The organic light emitting device according to the present invention has the effect of preventing the degradation of the luminous efficiency while extending the life of the device by preventing the penetration of moisture from the outside.

Claims (13)

A substrate; A stack structure consisting of a first electrode, a second electrode, and a plurality of organic films; And a cover plate formed at regular intervals on the laminate structure to surround the laminate structure as a whole. Forming an organic coating film for preventing moisture penetration on the outer surface of the organic light emitting device, The organic coating film is a polymer compound having a hydrophobic group, characterized in that formed of a material selected from any one of polyethylene, polyethylene derivatives, polypropylene or polypropylene derivatives. The organic electroluminescent device according to claim 1, wherein the organic coating layer is formed locally at a portion where the hydrophilic group compound is exposed to the external surface of the device. The organic light emitting device of claim 1, wherein the organic coating layer is formed on an entire outer surface of the organic light emitting device. The organic electroluminescent device according to claim 2, wherein the site in which the hydrophilic group compound is present comprises a site for adhering the substrate and the cover plate. The organic light emitting device of claim 3, wherein the entire outer surface of the organic light emitting device includes a cover plate and a portion for adhering the substrate to the cover plate. delete delete delete The organic electroluminescent device according to claim 1, wherein the polyethylene derivative and the polypropylene derivative comprise a halogen group. delete Board; A first electrode formed on the substrate; A plurality of organic laminated films formed on the first electrodes; Second electrodes formed on the plurality of organic stacked films; A protective film made of an organometallic compound or a polymer compound formed on the second electrode; A cover plate formed at regular intervals on the stack structure so as to surround the stack structure of the first electrode, the plurality of organic stacked films, the second electrode, and the protective film as a whole, and bonded to the substrate by an epoxy compound; And Is formed locally or entirely on the outer surface of the cover plate and the exposed surface of the epoxy compound, polytetrafluoroethylene, polytrifluoroethylene, polydifluoroethylene, polyfluoroethylene, polytetrachloroethylene, polytrichloro An organic electroluminescent device, characterized in that it comprises an organic coating film for preventing moisture penetration made of a material selected from any one of ethylene, polydichloroethylene or polychloroethylene. The organic light emitting device of claim 11, further comprising a moisture absorbent layer on a lower surface of the cover plate. The organic light emitting device of claim 12, further comprising a support layer on a lower surface of the moisture absorbent layer.

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