Abstract:
Provided is an organic light emitting device, which is flexible and is capable of effectively preventing permeation of oxygen or moisture. The organic light emitting device includes a substrate; a metal sheet that faces the substrate; an organic light emitting unit that is interposed between the substrate and the metal sheet; an adhesive unit that is interposed between the substrate and the metal sheet to adhere the substrate and the metal sheet to each other and that is located around at least the organic light emitting unit; and an adhesive layer that is formed at a location on the metal sheet where the metal sheet contacts the adhesive unit and that is formed of a metal oxide or a metal nitride.

Description:
CLAIM OF PRIORITY 
       [0001]    This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application for ORGANIC LIGHT EMITTING DISPLAY AND METHOD OF MANUFACTURING THE SAME earlier filed in the Korean Intellectual Property Office on 4 May 2010 and there duly assigned Korean Patent Application No. 10-2010-0042066. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    Aspects of the present invention relate to an organic light emitting display device and a method of manufacturing the same, and more particularly, to an organic light emitting display device including a metal film and a method of manufacturing the organic light emitting display device. 
         [0004]    2. Description of the Related Art 
         [0005]    Organic light emitting display devices generally have wide viewing angles, high contrast ratios, short response times, and reduced power consumption. Thus, the organic light emitting display may be used across a variety of applications such as personal portable devices (e.g., MP3 players and mobile phones) or large screen displays (e.g., television sets). 
         [0006]    Performance of an organic light emitting display device may deteriorate due to permeation of oxygen or moisture. Therefore, an organic light emitting display device requires a sealing structure for blocking permeation of oxygen and moisture. Furthermore, since such a sealing structure affects the flexibility of an organic light emitting display device, it is necessary to form the sealing structure by using a flexible material. 
       SUMMARY OF THE INVENTION 
       [0007]    Aspects of the present invention provide an organic light emitting device, which is flexible and is capable of effectively preventing permeation of oxygen or moisture. 
         [0008]    According to an aspect of the present invention, there is provided an organic light emitting display device including a substrate; a metal sheet that faces the substrate; an organic light emitting unit that is interposed between the substrate and the metal sheet; an adhesive unit that is interposed between the substrate and the metal sheet to adhere the substrate and the metal sheet to each other and that is located around at least the organic light emitting unit; and an adhesive layer that is formed at a location on the metal sheet where the metal sheet contacts the adhesive unit and that is formed of a metal oxide or a metal nitride. 
         [0009]    According to an aspect of the invention, the adhesive layer may be formed of a metal constituting the metal sheet and oxygen or nitrogen. 
         [0010]    According to an aspect of the invention, the metal sheet may be formed of aluminum, stainless steel, invar, magnesium, or an alloy thereof. 
         [0011]    According to an aspect of the invention, the adhesive unit may be formed of an epoxy-based adhesive, a silicon-based adhesive, or an acryl-based adhesive. 
         [0012]    According to an aspect of the invention, the substrate may be formed of a glass. 
         [0013]    According to another aspect of the present invention, there is provided a method of manufacturing an organic light emitting display device, the method including forming an organic light emitting unit on a substrate; preparing a metal sheet; forming an adhesive layer by performing plasma processing on at least a portion of a first surface of the metal sheet; forming an adhesive unit on the adhesive layer; arranging the first surface of the metal sheet to face the organic light emitting unit of the substrate, in such a way that the adhesive unit contacts the substrate; and hardening the adhesive unit. 
         [0014]    According to an aspect of the invention, the plasma processing may be performed on the first surface of the metal sheet by using O 2  plasma, N 2  plasma, Ar plasma, or H2 plasma. 
         [0015]    According to an aspect of the invention, the plasma processing may be performed after a mask including an opening that corresponds to a region in which the adhesive layer is to be formed, is arranged on the first surface of the metal sheet. 
         [0016]    According to an aspect of the invention, the metal sheet may be formed of aluminum, stainless steel, invar, magnesium, or an alloy thereof. 
         [0017]    According to an aspect of the invention, the adhesive unit may be formed of an epoxy-based adhesive, a silicon-based adhesive, or an acryl-based adhesive. 
         [0018]    According to an aspect of the invention, the substrate may be formed of a glass. 
         [0019]    According to an aspect of the invention, the method may further include forming a peeling layer on a second surface of the metal sheet; forming a supporting unit on the peeling layer; and hardening the adhesive unit and removing the supporting unit from the metal sheet by peeling the peeling layer. 
         [0020]    Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    A more complete appreciation of the invention, and many of the attendant advantages thereof, will be readily apparent as the same 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: 
           [0022]      FIG. 1  is a sectional view of an organic light emitting display device according to an embodiment of the present invention; 
           [0023]      FIG. 2  is a sectional view of an organic light emitting display device according to another embodiment of the present invention; and 
           [0024]      FIGS. 3 through 5  are sectional views sequentially showing a method of manufacturing the organic light emitting display device of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    Reference will now be made in detail to the present embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures. 
         [0026]      FIG. 1  is a sectional view of an organic light emitting display device according to an embodiment of the present invention. As shown in  FIG. 1 , an organic light emitting unit  3  is formed on a surface of a substrate  1 . The substrate  1  may be a glass substrate. However, the present invention is not limited thereto, and the substrate  1  may also be a plastic substrate. However, a glass substrate may be used when a high temperature process for fabricating thin-film transistors of pixel circuits of the organic light emitting unit  3  is to be performed. 
         [0027]    The organic light emitting unit  3  may include an organic light emitting device including an anode electrode, an organic thin-film layer, and a cathode electrode, and may further include a thin-film transistor for controlling operations of the organic light emitting device and a capacitor for storing signals. However, the invention is not limited thereto. For instance, the organic light emitting device can be otherwise constructed. Moreover, while described in terms of organic light emitting device, it is understood that aspects of the invention can be used with other types of light emitting units, such as where a non-organic light emitting unit can be used instead of the organic light emitting unit  3 . 
         [0028]    While not required in all aspects, a passivation film  4  is formed to cover the organic light emitting unit  3 . The passivation film  4  may be formed as a single layer or a multi layer of silicon nitride, silicon oxide, aluminum oxide, an organic material, or a combination thereof. Examples of combinations may include a stack of silicon nitride and silicon oxide, a stack of silicon nitride and aluminum oxide, and a stack of silicon nitride and an organic material. The passivation film  4  may be formed to have a thickness between about 0.2 μm to about 5 μm. However, the present invention is not limited thereto, and any of various materials may be applied as a single layer or as a plurality of layers in other thicknesses. 
         [0029]    A metal sheet  2  is arranged to face the substrate  1  on which the organic light emitting unit  3  and the passivation film  4  are formed. While not required in all aspects, the metal sheet  2  may be formed of aluminum, stainless steel, invar, magnesium, or an alloy thereof. While not required in all aspects, the metal sheet  2  may be formed to have a thickness between about 10 μm to about 10 mm, so that the metal sheet  2  simultaneously has sufficient hardness and sufficient flexibility. The metal sheet  2  includes a sheet body  21  and an adhesive layer  22 , which will be described in detailed later. 
         [0030]    The metal sheet  2  is adhered to the substrate  1  via a sealing member  51 . The sealing member  51  forms a closed-loop to surround the organic light emitting unit  3  and the passivation film  4 . Although  FIG. 1  shows that the sealing member  51  forms a single closed-loop only at edges of the substrate  1 , the configuration corresponds to a case of forming one organic light emitting display device by using one substrate  1 . Therefore, when forming a plurality of organic light emitting display devices by using one substrate  1 , a plurality of closed-loops as described above may be formed. Furthermore, the sealing member  51  may be additionally arranged to form double closed loops or triple closed loops. 
         [0031]    While not required in all aspects, the sealing member  51  may be formed of an epoxy-based adhesive, a silicon-based adhesive, an acrylic adhesive, or the like, and may be formed to have a thickness between about 5 μm to about 500 μm. Furthermore, since light may not transmit through the metal sheet  2  in aspects of the invention, the sealing member  51  may be formed of a thermal hardening adhesive. However, if it is possible to irradiate light from below the substrate  1 , an ultraviolet (UV) ray hardening adhesive may be used in other aspects. 
         [0032]    A space  6  is formed between the substrate  1  and the metal sheet  2 , which are adhered to each other and sealed by the sealing member  51 . While shown as empty, the space  6  may be filled with a filler. The filler may be formed of a colorless liquid material or a colorless gel-like material that exhibits transmittance above 95% at a thickness under 30 μm. Examples of gel-like materials may include an epoxy, urethane acrylate, epoxy acrylate, or a silicon-based resin (e.g., bisphenol A type epoxy, cycloaliphatic epoxy resin, phenyl silicon resin or rubber, acrylic epoxy resin, aliphatic urethane acrylate, or the like). The filler as a gel-like material may fill the space  6  as a liquid and is hardened by irradiating an electron beam or a UV ray thereto. Alternatively, the filler as a gel-like material may be molded into a film and attached to the passivation layer  4 . Furthermore, examples of liquid materials may include a silicon material, e.g., a silicon oil, that exhibits no change of phase and a volume variation below 5% within about −40° C. to about 100° C. (e.g., a material selected from the group consisting of hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, dodecamethylpentasiloxane, and polymethylsiloxanes). Also, a moisture absorbing material may be added to the filler. Examples of the moisture absorbing material include, but are not limited to, CaO, BaO, a zeolite-based or aluminum-based organometallic complex, a moisture absorbing polymer such as a polyacryrilic acid, or the like. 
         [0033]    As shown in  FIG. 1 , the metal sheet  2  includes the sheet body  21  and the adhesive layer  22 . The sheet body  21  corresponds to a portion of the metal sheet  2  that is formed of a metal, whereas the adhesive layer  22  is formed at least on a portion of the metal sheet  2  contacting the sealing member  51 . 
         [0034]    The adhesive layer  22  is formed of a metal oxide or a metal nitride. At this point, the metal oxide or the metal nitride constituting the adhesive layer  22  may be a compound of the metal constituting the sheet body  21  of the metal sheet  2  and oxygen or nitride. For example, in the case where the sheet body  21  of the metal sheet  2  is formed of aluminum, the adhesive layer  22  may be formed of aluminum oxide or aluminum nitride. 
         [0035]    The adhesive layer  22  improves adhesiveness between the metal sheet  2  and the sealing member  51 . The adhesiveness between the metal sheet  2  and the sealing member  51  decreases due to the metal sheet  2  and the sealing member  51  having different thermal expansion ratios. Therefore, if an organic light emitting display device is used for an extended period of time, moisture or oxygen may permeate from an interface between the metal sheet  2  and the sealing member  51 . According to aspects of the present invention, the metal sheet  2  may be firmly attached to the sealing member  51  by forming the adhesive layer  22 . 
         [0036]      FIG. 2  is a sectional view of an organic light emitting display device according to another embodiment of the present invention. A sealing layer  52  is formed on the substrate  1  to completely cover the passivation film  4 . The sealing layer  52  may be formed of an epoxy-based adhesive, a silicon-based adhesive, an acrylic adhesive, or the like, wherein the sealing layer  52  may be formed to have a thickness between about 5 μm to about 500 μm. The sealing layer  52  may be formed of a thermal hardening adhesive. Furthermore, the sealing layer  52  may be formed of a thermal sheet. 
         [0037]    Since the sealing layer  52  is formed on the substrate  1  to completely cover the passivation film  4  as described above, the adhesive layer  22  may be formed on an entire surface of the metal sheet  2 . In this case, the adhesiveness between the metal sheet  2  and the sealing layer  52  may be significantly improved due to the adhesive layer  22 . 
         [0038]    The adhesive layer  22  may be formed to have a thickness between about 0.1 μm to about 10 μm. If the thickness of the adhesive layer  22  is smaller than 0.1 μm, it is difficult to expect improved adhesiveness due to the adhesive layer  22 . In contrast, if the thickness of the adhesive layer  22  exceeds 10 μm, excessive time and energy are consumed for formation of the adhesive layer  22 , and thus productivity decreases. Furthermore, in this case, moisture or oxygen may permeate through the adhesive layer  22 . 
         [0039]    Next, referring to  FIGS. 3 through 5 , a method of manufacturing the organic light emitting display device of  FIG. 1  according to an embodiment of the present invention will be described. As shown in  FIG. 3 , a peeling layer  23  is formed on a rear surface of the metal sheet  2 . A supporting body  24  is formed on the peeling layer  23 , so that the metal sheet  2  may be handled easily. The supporting body  24  and the metal sheet  2  may be separated from each other by irradiating a laser or a UV ray onto the peeling layer  23  or by heating the peeling layer  23 . 
         [0040]    A mask  7  is disposed on the metal sheet  2 . The mask  7  has a shield portion  72  and an opening  71  that corresponds to an area A in which the adhesive layer  22  is to be formed. 
         [0041]    While the mask  7  is disposed on a top surface of the metal sheet  2 , plasma processing is performed from above the mask  7 . A plasma used for the plasma processing may be O 2  plasma, N 2  plasma, Ar plasma, or H2 plasma. Then, the adhesive layer  22  is formed on the sheet body  21  of the metal sheet  2  by performing the plasma processing via the opening  71 . In other words, the adhesive layer  22  is an oxide or a nitride of the metal constituting the metal sheet  2 , which is formed by performing plasma processing on a portion of the sheet body  21  of the metal sheet  2 . While described in terms of processing using plasma processing to produce the adhesive layer  22 , it is understood that other mechanisms can be used to create the adhesive layer  22 . Moreover, it is understood that the metal in the adhesive layer  22  need not be the same as the metal in the sheet body  21  in all aspects. 
         [0042]    As shown in  FIG. 4 , the sealing member  51  is applied on the adhesive layer  22 . Then, the metal sheet  2 , on which the sealing member  51  is applied and on which the supporting unit  24  is attached, is arranged on the substrate  1 , on which the organic light emitting unit  3  and the passivation film  4  are formed. At this point, the sealing member  51  may become a closed-loop surrounding the organic light emitting unit  3  and the passivation film  4 . 
         [0043]    Next, the sealing member  51  is hardened and the supporting unit  24  is removed from the metal sheet  2  by peeling the peeling layer  23 . 
         [0044]    The structure according to the embodiment shown in  FIG. 2  may be formed by not using the mask and performing plasma processing on an entire surface of the metal sheet  2 . 
         [0045]    As described above, according to aspects of the present invention, permeation of moisture or oxygen into an organic light emitting display device may be blocked by simply forming a metal oxide or a metal nitride at a location where a metal sheet contacts a sealing member by performing plasma processing on the metal sheet. 
         [0046]    According to embodiments of the present invention as described above, an organic light emitting display device with shock-resistance and flexibility due to a metal sheet may be provided. 
         [0047]    Furthermore, adhesiveness between a sealing member and a metal sheet may be improved by interposing an adhesive layer formed of a metal oxide or a metal nitride therebetween, and thus permeation of oxygen and moisture may be blocked. 
         [0048]    While described in terms of being used in an organic light emitting display device, it is understood that aspects can by used in other flexible and rigid display devices, such as field emission displays, LCDs, and PDPs. 
         [0049]    Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.