KR20070033701A - Flat Panel Display - Google Patents

Abstract

The present invention relates to a flat panel display. According to an aspect of the present invention, there is provided a flat panel display comprising: an insulating substrate provided with an electrostatic discharge protection circuit; A sealing substrate opposed to the insulating substrate; A conductive layer applied to at least one surface of the sealing substrate and electrically connected to the electrostatic discharge protection circuit; And sealants disposed at edges of both substrates to bond the two substrates together. As a result, a flat panel display device capable of safely removing static electricity accumulated on a surface of a sealing substrate is provided.

Description

Flat Panel Display {FLAT PANEL DISPLAY}

1 is a cross-sectional view of a flat panel display device according to a first embodiment of the present invention;

2 is a cross-sectional view of a flat panel display device according to a second exemplary embodiment of the present invention.

Explanation of Signs of Major Parts of Drawings

10: OLED panel 110: sealing substrate

120: conductive layer 130: sealant

210: insulating substrate 275: pixel electrode

280: partition 283: organic light emitting layer

285: common electrode 290: electrostatic discharge protection circuit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display, and more particularly, to a flat panel display that can safely remove static electricity accumulated on a surface of a sealing substrate.

BACKGROUND OF THE INVENTION Organic light emitting diodes (OLEDs) have recently come into the spotlight due to advantages such as low voltage driving, light weight, wide viewing angle, and high-speed response among flat panel displays. OLEDs are classified into a passive matrix and an active matrix according to the driving method. Among them, the passive type has a simple manufacturing process, but the power consumption increases rapidly as the display area and resolution increase. Therefore, the passive type is mainly applied to small displays. Active type, on the other hand, has a complex manufacturing process but has the advantage of realizing a large screen and high resolution.

Such an OLED includes a thin film transistor including a gate electrode, a source electrode, and a drain electrode made of at least one metal, a pixel electrode connected to the thin film transistor, a partition wall separating the pixel electrode, and a pixel in the region between the partition walls. An organic light emitting layer formed on the electrode and a common electrode formed on the organic light emitting layer.

Here, the performance and lifespan of the organic light emitting layer is sensitive to moisture and oxygen and can be easily deteriorated. In order to prevent deterioration of the organic light emitting layer, a sealing process is required in which a sealing substrate is bonded to an insulating substrate to protect the organic light emitting layer from oxygen and moisture.

Electrostatics are generated by mutual bonding or friction of objects with different charges (sealing substrates, insulating substrates, etc.) in the bonding process between the insulating substrate and the sealing substrate, or by UV used in the OLED manufacturing process. However, such static electricity is accumulated on the surface of the sealing substrate because the sealing substrate is made of an insulator such as glass or plastic and does not disperse or escape to the outside.

However, over time, the static electricity accumulated on the surface of the sealing substrate has a high energy and rapidly discharges at one moment. This phenomenon is called an electrostatic discharge (ESD) phenomenon. If such ESD phenomenon occurs between the metal layer (gate electrode, source and drain electrode, etc.) of the OLED panel and the sealing substrate, there is a problem that causes a failure in the OLED panel due to the rapid discharge of static electricity having a high energy level.

Accordingly, an object of the present invention is to provide a flat panel display device which can safely remove static electricity accumulated on the surface of a sealing substrate.

The object is, according to the present invention, an insulating substrate provided with an electrostatic discharge protection circuit; A sealing substrate opposed to the insulating substrate; A conductive layer applied to at least one surface of the sealing substrate and electrically connected to the electrostatic discharge protection circuit; And a sealant disposed at edges of both substrates to bond the two substrates to each other.

Here, the conductive layer can be temporarily conductive.

The conductive layer may be coated on a surface facing the insulating substrate.

In addition, the sealant is in contact with at least a portion of each of the electrostatic discharge protection circuit and the conductive layer, and the sealant may be conductive.

Here, the static electricity accumulated on the surface of the sealing substrate is preferably removed to prevent the ESD through at least one of the conductive layer, the electrostatic discharge protection circuit and the sealant.

The sealing substrate may be any one of a flat glass substrate and a plastic film.

In addition, the sealing substrate may be a canister.

Here, a moisture absorbent may be provided on one surface of the sealing substrate facing the insulating substrate.

The sealant may be cured by at least one of light and heat.

In addition, a thin film transistor provided on the insulating substrate; A pixel electrode connected to the thin film transistor; Barrier ribs separating pixel electrodes; An organic light emitting layer formed on the pixel electrode between the partition walls; And a common electrode formed on the organic light emitting layer.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. Hereinafter, the OLED will be described as an example among various flat panel display devices. However, the present invention is not limited thereto, and it can be applied to other flat panel display devices such as a liquid crystal display (LCD) and a PDP. In addition, the fact that a film is formed (positioned) on another layer is not only when two films are in contact with each other, but another film is between the two films. It also includes the case where it exists.

1 is a cross-sectional view of a flat panel display device according to a first embodiment of the present invention.

The flat panel display according to the present invention includes an OLED panel (10). As shown in FIG. 1, the OLED panel 10 includes a thin film transistor T formed on an insulating substrate 210, a pixel electrode 275 electrically connected to the thin film transistor T, and a pixel electrode ( 275, a partition wall 280 that partitions the gap, an organic light emitting layer 283 formed on the pixel electrode 275 surrounded by the partition wall 280, and a common electrode 285 covering the partition wall 280 and the organic light emitting layer 283. And an encapsulation substrate 110 which is in contact with the insulating substrate 210 to protect the organic light emitting layer 283 from moisture and oxygen.

In the embodiment of the present invention, a thin film transistor (T) using amorphous silicon is exemplified, but a thin film transistor using polysilicon may be used. Looking at the thin film transistor (T) in detail as follows.

The gate electrode 220 is formed on an insulating substrate 210 made of an insulating material such as glass, quartz, ceramic, or plastic. A gate insulating layer 230 made of silicon nitride (SiNx) or the like is formed on the insulating substrate 210 and the gate electrode 220. On the gate insulating layer 230 where the gate electrode 220 is located, a semiconductor layer 240 made of amorphous silicon and ohmic contacts 251 and 252 made of n + hydrogenated amorphous silicon heavily doped with n-type impurities are sequentially formed. . Here, the ohmic contacts 251 and 252 are separated from both sides of the gate electrode 220.

The source electrode 262 and the drain electrode 263 are formed on the ohmic contacts 251 and 252 and the gate insulating layer 230. The source electrode 262 and the drain electrode 263 define a channel region while the region corresponding to the gate electrode 220 is removed and separated to both sides.

The passivation layer 270 is formed on the source electrode 262, the drain electrode 263, and the semiconductor layer 240 that is not covered. The passivation layer 270 may be formed of silicon nitride (SiNx) and / or an organic layer. The passivation hole 271 exposing the drain electrode 263 is formed in the passivation layer 270. The pixel electrode 275 is formed on the passivation layer 270. The pixel electrode 275 is also called an anode and supplies holes to the organic light emitting layer 283. The pixel electrode 275 is made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

A partition wall 280 is formed between each pixel electrode 275 on the passivation layer 270. The partition wall 280 defines a pixel area by dividing the pixel electrodes 275 and is formed on the thin film transistor T and the contact hole 271. The partition wall 280 also prevents the source electrode 262 and the drain electrode 263 of the thin film transistor T from being short-circuited with the common electrode 285. The partition wall 280 may be formed of a photoresist having heat resistance and solvent resistance, such as an acrylic resin and a polyimide resin, or an inorganic material such as SiO 2 or TiO 2, and may have a two-layer structure of an organic layer and an inorganic layer.

An organic light emitting layer 283 is formed on the pixel electrode 275 surrounded by the partition 280. The holes transferred from the pixel electrode 275 and the electrons transferred from the common electrode 285 are combined in the organic light emitting layer 283 to become excitons, and then generate light in the process of deactivating the excitons. Although not shown, a hole injection layer and / or a hole transport layer may be further included between the organic light emitting layer 283 and the pixel electrode 275, and an electron injection layer between the organic light emitting layer 283 and the common electrode 285. Or it may further comprise an electron transport layer. The organic light emitting layer 283 may be degraded in performance and life due to moisture and oxygen. Thus, in order to protect the organic light emitting layer 283 from moisture and oxygen, the organic light emitting layer 283 is sealed using the sealing substrate 110.

The illustrated organic light emitting layer 283 is of a polymer type and may be formed by an inkjet method. The organic light emitting layer 283 is a polyfluorene derivative, a (poly) paraphenylene vinylene derivative, a polyphenylene derivative, a polyvinylcarbazole, a polythiophene derivative, or a polymeric material such as a perylene pigment, a rodinamine pigment, Rubene, perylene, 9,10-diphenylanthracene, tetraphenylbutadiene, nile red, coumarin 6, quinacridone and the like can be used by doping. If the organic light emitting layer 283 is a low molecular organic material type rather than a polymer type, the organic light emitting layer 283 may be formed by an evaporation method. When the organic light emitting layer 283 is a polymer or a low molecular organic material, unlike the inorganic material, since the performance and life of the organic light emitting layer 283 are greatly influenced by moisture and oxygen, the organic light emitting layer 283 should be properly protected from moisture and oxygen.

The common electrode 285 is disposed on the partition wall 280 and the organic light emitting layer 283. The common electrode 285 is also called a cathode and supplies electrons to the organic light emitting layer 285. The common electrode 285 may be formed by stacking a calcium layer and an aluminum layer or a barium layer and an aluminum layer.

On the other hand, the electrostatic discharge protection circuit 290 is provided on the insulating substrate 210. The electrostatic discharge protection circuit 290 is a circuit for discharging or discharging static electricity generated in the manufacturing process of the OLDE panel 10 to the outside. Although the electrostatic discharge protection circuit 290 is provided on one side corresponding to the pad 291 in the drawing, this is briefly illustrated to explain the present invention and may be provided anywhere where static electricity accumulates. The electrostatic discharge protection circuit 290 may be connected to the thin film transistor T for driving the pixel. As shown in FIG. 1, an electrostatic discharge protection circuit 290 is connected to a pad 291, and the pad 291 is in contact with at least a portion of each of the conductive layer 120 and the sealant 130. The pad 291 may be either a gate pad or a data pad, and may be manufactured simultaneously with the data pad or the gate pad. The pad 291 may be made of a conductive material, and ITO or IZO may be used. The electrostatic discharge protection circuit 290 may safely disperse or remove not only static electricity generated in the OLED manufacturing process but also at least one of the conductive layer 120 and the sealant 130.

The performance and lifespan of the organic light emitting layer 283 are sensitive to moisture and oxygen, thereby protecting the organic light emitting layer 283 from moisture and oxygen by using the sealing substrate 110. The sealing substrate 110 according to the first embodiment of the present invention is opposed to the insulating substrate 210 having the organic light emitting layer 283 provided with a flat organic substrate or a plastic film. The thickness of the sealing substrate 110 may be 0.1mm or more. The conductive layer 120 is coated on one surface of the sealing substrate 110 facing the insulating substrate 210. The conductive layer 120 may be a paint liquid, is coated on the entire surface of the sealing substrate 110, and is electrically connected to the electrostatic discharge protection circuit 290 described above. As shown in FIG. 1, the conductive layer 120 may be connected to the pad 291 through the sealant 130. Unlike the exemplary embodiment, the conductive layer 120 may be directly connected to the pad 291. As a result, the static electricity accumulated on the surface of the sealing substrate 110 as an insulator during the sealing process flows to the static discharge protection circuit 290 through the conductive layer 120 and is safely removed. Therefore, the defect of the OLED panel 10 caused by the discharge of static electricity of high energy level at a time is eliminated.

Here, the conductive layer 120 may be temporarily conductive. This is because the conductive layer 120 is sufficient to flow static electricity generated in the sealing process into the electrostatic discharge protection circuit 290 even if it is temporarily conductive. In addition, an electrical short may be generated between the pad 291, the data pad, and the gate pad due to the damage of the gate insulating layer 230 or the protective layer 270 covering the pad 291 in the manufacturing process. Electrical interference may also occur in relation to other components when driving. Temporarily conductive materials can be used to reduce such short or electrical interference. The conductive layer 120 may be transparent, and generally conductive ESD paint may be used. ESD paints include TARAPATH's 'ACL Staticide 10R Primer for ESD Paint', NEWARK inone's '4700-SS1', ACL, INC. (Illinois, USA), ALX Technical (Canada), Anti-static Resources Corporation (USA) , New York), Botron Company (Arizona, USA), Butchers (USA, Maine), Bystat International, Inc. (USA, New York), Correct Products (USA, Texas), Desco (USA, California), ESD Manufacturing and Supply ( Singapore), ESD Systems.com (Maine, USA), Garland Floor Company (Ohio, USA), Key Industries (Wisconsin, USA), Marshall Industries (USA, California), Sauereisen (Pennsylvania, USA), SC Technologies (USA, Colorado), LLC. And Semtronics Corporation (Georgia, USA).

The OLED panel 10 according to the first embodiment of the present invention further includes a sealant 130 disposed at an edge of the sealing substrate 110 and the insulating substrate 210 to bond the two substrates 110 and 210 to each other. . The sealant 130 functions to bond both substrates 110 and 210 to each other and to seal the organic semiconductor layer 283, and to flow static electricity accumulated on the surface of the sealing substrate 110 to an electrostatic discharge protection circuit. Can be. In this case, the sealant 130 should be conductive and in contact with at least a portion of each of the electrostatic discharge protection circuit 290 and the conductive layer 120. That is, the static electricity accumulated on the surface of the sealing substrate 110 may be removed through at least one of the conductive layer 120, the electrostatic discharge protection circuit 290, and the sealant 130. The sealant 130 may be cured by light or heat.

Hereinafter, a second embodiment of the present invention will be described with reference to FIG. 2. In the second embodiment, only the characteristic parts distinguished from the first embodiment will be described and described, and the unexplained parts are in accordance with the above-described first embodiment. And, the same components or components that achieve the same function will be described using the same reference numerals.

2 is a cross-sectional view of the OLED panel 10 according to the second embodiment of the present invention, and the canister is used as the sealing substrate 110. The canister 110 has a shape where the edge is bent toward the insulating substrate 210, and the bent edge portion abuts against the insulating substrate 210 to seal the canister 110. Canister 110 is typically manufactured using soda-lime glass. The canister 110 and the insulating substrate 210 are bonded to each other using the sealant 130 which is cured by light or heat, and an absorbent 150 is attached to the inner wall of the canister 110. The space surrounded by the canister 110 and the insulating substrate 210 is usually filled with nitrogen. As illustrated in FIG. 2, the conductive layer 120 may be directly connected to the pad 291 to allow static electricity accumulated on the surface of the canister 110 to flow into the electrostatic discharge protection circuit 290. ) May be provided as a conductive material so that static electricity may be dispersed or removed through the sealant 130.

As described above, according to the present invention, there is provided a flat panel display device capable of safely removing the static electricity accumulated on the surface of the sealing substrate.

Claims (10)

An insulating substrate provided with an electrostatic discharge protection circuit; A sealing substrate opposed to the insulating substrate; A conductive layer applied to at least one surface of the sealing substrate and electrically connected to the electrostatic discharge protection circuit; And And a sealant disposed at edges of the substrates to bond the substrates to each other. The method of claim 1, And the conductive layer is temporarily conductive. The method of claim 2, And the conductive layer is coated on a surface facing the insulating substrate. The method of claim 1, And the sealant is in contact with at least a portion of each of the electrostatic discharge protection circuit and the conductive layer, and the sealant is conductive. The method of claim 4, wherein The static electricity accumulated on the surface of the sealing substrate is removed through at least one of the conductive layer, the electrostatic discharge protection circuit and the sealant. The method of claim 1, The sealing substrate is a flat panel display device, characterized in that any one of a flat glass substrate and a plastic film. The method of claim 1, And the sealing substrate is a canister. The method of claim 7, wherein And a moisture absorbent is provided on one surface of the sealing substrate facing the insulating substrate. The method of claim 1, And the sealant is cured by at least one of light and heat. The method of claim 1, A thin film transistor provided on the insulating substrate; A pixel electrode connected to the thin film transistor; Barrier ribs separating the pixel electrodes; An organic light emitting layer formed on the pixel electrode between the partition walls; And And a common electrode formed on the organic light emitting layer.

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