Patent Application
20070273280
A more complete appreciation of the present invention and many of the attendant advantages thereof, will be readily apparent as the present invention becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference symbols indicate the same or similar components, wherein:
The present invention is described more fully below with reference to the accompanying drawings in which exemplary embodiments of the present invention are shown.
Referring to
The light emitting unit 120 displays a predetermined image by emitting red, green, and blue light according to a current flow, and includes a first electrode layer 121 that functions as an anode to inject holes, a second electrode layer 125 that functions as a cathode to injects electron, and an active layer 123 that is interposed between the first and second electrode layers 121 and 125 and generates light by recombining the holes and electrons. The first electrode layer 121 may be formed of a material having a large work function, for example, transparent ITO. The second electrode layer 125 may be formed of a material having a small work function, for example, by depositing Mg/Ag, Mg, Al, or an alloy of these metals. The active layer 123 interposed between the first and second electrode layers 121 and 125 can be formed of a small molecular weight organic film or a polymer organic film. If the active layer 123 is formed of a small molecular weight organic film, the active layer 123 can be formed by stacking a Hole Injection Layer (HIL), a Hole Transport Layer (HTL), an organic Emitting Material Layer (EML), an Electron Transport Layer (ETL), or an Electron Injection Layer (EIL). If the active layer 123 is formed of a polymer organic film, the active layer 123 usually has a structure in which the HTL and the EML are included. The structure of the active layer 123 is not limited thereto, that is, the active layer 123 can be a single layer EML structure, a double layer HTL/EML structure, or a double layer EML/ETL structure.
The passivation layer 130 having a multiple layer structure in which a plurality of barrier layers 130a and a buffer layer 130b are stacked one after the other to prevent the penetration of harmful materials from the air into the light emitting unit 120 is formed on the light emitting unit 120. The passivation layer 130 is formed by alternately stacking the barrier layer 130a and the buffer layer 130b, and may include at least two layers of thin films to ensure the minimum blocking efficiency with respect to the external harmful materials.
The blocking of impurities is mainly achieved by the barrier layer 130a. The barrier layer 130a can be formed of an activated metal oxide, an activated metal nitride, or an activated metal oxynitride. The activated metal oxide denotes a metal oxide in an activated unstable state derived from a stable metal oxide due to a deficiency of an oxygen atom. More specifically, examples of the activated metal oxide are Al2OX(1<X<3), BaOX(0<X<1), In2OX(1<X<3), TiOX(1<X<2), MgOX(0<X<1), GeOX(0<X<1), CaOX(0<X<2), SrOX(0<X<1), Y2OX(0<X<3), HfOX(0<X<2), ZrOX(0<X<2), MoOX(0<X<3), and V2OX(0<X<5). The activated metal nitride denotes a metal nitride in an activated unstable state derived from a stable metal nitride due to a deficiency in a nitrogen atom. More specifically, some examples of the activated metal nitride are, AlNX(0<X<1) and GaNX(0<X<1). Also, the activated metal oxynitride denotes a metal oxynitride in an activated unstable state derived from a stable metal oxynitride due to a deficiency in an oxygen and/or nitrogen atom. More specifically, an example of the activated metal oxynitride is SiOXNY(0<X<2)(0<Y<2). Hereinafter, the activated metal oxide, the activated metal nitride, and the activated metal oxynitride will be commonly called the activated metal oxynitride. The activated metal oxynitride, while it stabilizes on its own, functions to absorb impurities through a chemical reaction with the oxygen and/or nitrogen that penetrate into the organic light emitting device. The barrier layer 130a can be formed of an oxide, a nitride, or an oxynitride of 2A, 3A, 4A, 3B, or 4B family metal. However, the present invention is not limited to these metals.
The buffer layer 130b can be formed of a polymer organic material or a small molecule organic material and is interposed between the barrier layers 130a. The buffer layer 130b strengthens the barrier layer 130a that is relatively weak, prevents the barrier layer 130a from being damaged because of brittleness, and provides a better condition for forming the barrier layer 130a so that the passivation layer 130 can be formed to be more than a predetermined thickness. For example, the buffer layer 130b can be formed by a vapor deposition polymerization method in which a polymer organic film is obtained by a polymerization reaction after a precursor material is deposited by vacuum evaporation on a target material. Otherwise, the buffer layer 130b can be formed by a vapor deposition method in which a small molecule organic film is obtained. The polymer organic materials are, for example, polyurea, polyimide, and polyamide. The buffer layer 130b can also be formed by polymerization methods using conventional thermal heating, using a laser or a heat bar, or using an electromagnetic induction heating or ultra sonic friction besides the vapor deposition polymerization method. The polymerization method of forming the buffer layer 130b can be appropriately selected according to the material for forming the buffer layer 130b.
In
The passivation layer 130 may be formed not only on an upper surface of the light emitting unit 120 that is an element that is to be protected, but also on a lower surface of the insulating substrate 110 in order to block the penetration of harmful materials. The passivation layer 130 formed on the lower surface of the insulating substrate 110 has substantially the same configuration as the passivation layer 130 formed on the upper surface of the light emitting unit 120, and accordingly, includes a plurality of barrier layers 130a and buffer layers 130b that are alternately stacked. Therefore, the descriptions of the barrier layer 130a and the buffer layer 130b have not been repeated.
The insulating substrate 210 supports the organic electronic device, and can be formed of a glass material or a flexible polymer material. The gate electrode 221 formed on the insulating substrate 210 can be formed of a conventional metal, such as Au, Ag, Al, Cu, or Ni. The organic insulating film 223 that insulates the gate electrode 221 by burying the gate electrode 221 is formed on the insulating substrate 210, and can be formed of Polyvinylpyrolidone (PVP), polyimide, Benzocyclobutene (BCB), and photoacryl.
The source electrode 225 and the drain electrode 227 are formed on predetermined regions on the organic insulating film 223, and the source electrode 225 and the drain electrode 227 can be formed of a metal electrode material similar to the gate electrode 221. The organic semiconductor layer 229 provides a conductive path between the source electrode 225 and the drain electrode 227 and is formed on the organic insulating film 223 between the source electrode 225 and the drain electrode 227. The organic semiconductor layer 229 can be formed of pentacene, polyacetylene, polyaniline, or a derivative of these materials.
The passivation layer 231 seals the thin film structures that are beneath the inner side of the passivation layer 231 to prevent the gate electrode 221, the source electrode 225, and the drain electrode 227 from oxidizing or corroding and to prevent the organic insulating film 223 and the organic semiconductor layer 229 from degrading due to a reaction with oxygen or moisture. The passivation layer 231 has a structure in which barrier layers 231a and buffer layers 231b are alternately stacked. The barrier layers 231a block a reaction between external harmful materials and the inner thin film structures (including the gate electrode 221, the source electrode 225, the drain electrode 227, and the organic semiconductor layer 229). The buffer layers 231b prevent the brittlely damage of the barrier layers 231a that are weak, and provide a better condition for forming the barrier layer 213a so that the passivation layer 231 can be formed to be more than a predetermined thickness. The barrier layers 231a can be formed of an activated metal oxynitride, and the buffer layers 231b can be formed of a polymer organic material. The activated metal oxynitride is a compound in a state that an oxygen atom or a nitrogen atom lacks from a stable composed composition. The activated metal oxynitride, while it stabilizes on its own, prevents harmful components, such as oxygen or nitrogen, from penetrating into the organic electronic device through a reaction with the harmful components. The buffer layers 231b can be formed of a polymer organic material, such as polyurea, polyimide, polyamide that can be vapor deposition polymerized. The buffer layers 231b can also be formed of various polymer organic materials that can be polymerized by conventional heating, electromagnetic induced heating, laser or a heat bar, or ultrasonic friction.
An additional passivation layer 232 can be formed on a lower surface of the insulating substrate 210. The passivation layer 232 is not an essential element in the present invention, but can be implemented together with the passivation layer 231 covering the organic semiconductor layer 229 to obtain maximal blockage from the penetration of the impurities. The passivation layer 232 on the lower surface of the insulating substrate 210 can also be formed in a structure in which a plurality of barrier layers 232a and buffer layers 232b are alternately stacked, and thus, the descriptions thereof have not been repeated.
According to the present invention, an organic electronic device is not sealed in a can but is sealed with multiple passivation layers, thereby providing a thin and light-weight organic electronic device. In particular, harmful materials that can penetrate into the organic light emitting device can be effectively blocked since the passivation layer includes an activated metal oxynitride. Accordingly, a formation of dark points that decrease the display function ability and reduce luminance is substantially prevented.
While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various modifications in form and detail may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2006-0047221 | May 2006 | KR | national |
