Abstract:
An organic light emitting display includes a first substrate including a plurality of anode electrodes on an insulating layer and a plurality of pixel definition layers around the plurality of anode electrodes. An impact absorbing layer is spaced from the plurality of pixel definition layers, and a spacer is on an upper surface of the impact absorbing layer. A second substrate faces the first substrate and is spaced from the first substrate by the spacer.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to and the benefit of Korean Patent Application No. 10-2008-0009614, filed on Jan. 30, 2008, in the Korean Intellectual Property Office, the entire content of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an organic light emitting display and a method for manufacturing the same. 
     2. Description of Related Art 
     Recently, various flat panel display devices having reduced weight and volume compared to cathode ray tube device have been developed. Exemplary flat panel display devices include a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP) and an organic light emitting display (OLED), among others. 
     An organic light emitting display displays an image using an organic light emitting diode (OLED) generating light by recombination of electrons and holes. 
     An organic light emitting diode includes an anode electrode, a cathode electrode and an emission layer positioned between the anode electrode and the cathode electrode. When a current flows in a direction from the anode electrode to the cathode electrode, a color is expressed through light emission. 
     The market for such organic light emitting displays having excellent color reproducibility, a relatively thin configuration, etc. has been largely expanded into various applications such as personal digital assistants (PDAs), MP3 players, etc. in addition to cellular phones. 
     A conventional organic light emitting display may include a transparent substrate on which a thin film transistor and an organic light emitting diode etc. are formed, and a seal substrate sealing the transparent substrate. A spacer is included between the transparent substrate and the seal substrate in order to constantly maintain a distance therebetween. 
     In the organic light emitting display constituted as above, when impact is applied to the seal substrate or the transparent substrate from the outside, the impact may be transferred to the spacer. 
     The impact transferred to the spacer can also be transferred to the organic light emitting diode, thereby damaging the organic light emitting diode. In particular, the greater the impact strength transmitted, the greater the degree of damage to the organic light emitting diode becomes. A damaged organic light emitting diode does not emit light, potentially causing blurs to appear on the organic light emitting display. 
     The occurrence of a defect to an internal device is checked by a bending test and a ball drop test to evaluate the device&#39;s strength. If the device does not endure a threshold strength, the device is judged as insufficient to be launched in the market. 
     Accordingly, the strength of a device&#39;s organic light emitting display is important, and increasing the device&#39;s strength is also important. 
     SUMMARY OF THE INVENTION 
     According to aspects of the present invention, an organic light emitting display is provided with improved durability by including an impact absorbing layer and a method for manufacturing the same. 
     In one embodiment of the present invention, an organic light emitting display is provided including a first substrate having a plurality of anode electrodes on an insulating layer and a plurality of pixel definition layers around the plurality of anode electrodes. An impact absorbing layer is spaced from the plurality of pixel definition layers, and a spacer is on the impact absorbing layer. A second substrate faces the first substrate and is spaced from the first substrate by the spacer. 
     In one embodiment, an inert gas or an organic material is in a space between the first substrate and the second substrate. Further, the pixel definition layer and the impact absorbing layer may comprise the same material and may be formed by the same process. 
     In another embodiment, a method for manufacturing an organic light emitting display is provided including forming a thin film transistor on glass, forming an insulating layer on an upper surface of the thin film transistor, forming a plurality of anode electrodes electrically coupled to the thin film transistor on the insulating layer, forming a plurality of pixel definition layers positioned around the plurality of anode electrodes and impact absorbing layers spaced from the plurality of pixel definition layers by forming and patterning the insulating layer on the plurality of anode electrodes, and forming a spacer on the impact absorbing layer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, together with the specification, illustrate exemplary embodiments of the present invention, and, together with the description, serve to explain the principles of the present invention. 
         FIG. 1  is a plan view showing an organic light emitting display. 
         FIG. 2  is a cross-sectional view of the organic light emitting display according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, only certain exemplary embodiments of the present invention have been shown and described, simply by way of illustration. As those skilled in the art will realize, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. In addition, when an element is referred to as being “on” another element, it can be directly on the element or be indirectly on the element with one or more intervening elements interposed therebetween. Also, when an element is referred to as being “connected to” another element, it can be directly connected to the element or be indirectly connected to the element with one or more intervening elements interposed therebetween. Hereinafter, like reference numerals refer to like elements. 
       FIG. 1  is a plan view showing an organic light emitting display. 
     Referring to  FIG. 1 , an organic light emitting display includes a transparent substrate and a seal substrate. Herein, the transparent substrate includes a thin film transistor, an insulating layer and an anode electrode  10  of the organic light emitting diode, etc. formed on an upper surface thereof. Also, a pixel definition layer (PDL) layer  11  is formed on the upper surface of the anode electrode  10 . The anode electrode is exposed in a specific region, for example, an emission region  12  that emits light. The emission region  12  is formed with an emission layer to form an organic light emitting diode. The organic light emitting diode is electrically coupled to the thin film transistor to emit light corresponding to a signal transmitted from thin film transistor. A plurality of spacers  13  are formed on one region of the PDL layer  11 . The spacers  13  function to constantly maintain a distance between the transparent substrate and the seal substrate. 
     When impact from the outside is applied to the seal substrate or the transparent substrate of the organic light emitting display constituted as above, the impact is transferred to the spacer  13 . 
     When the impact is transferred to the spacer  13 , the impact may be further transferred to the PDL layer  11  on the lower surface of the spacer. The impact transferred to the PDL layer  11  can also be transferred to the emission layer and the anode electrode  10 . Therefore, if the transferred impact strength is large, the organic light emitting diode may be damaged, preventing the organic light emitting diode from emitting light. As such, blurs may appear on the organic light emitting display. 
     Accordingly, embodiments of the present invention include an organic light emitting display having an impact absorbing layer to prevent or significantly reduce damage to the organic light emitting display. Hereinafter, the detailed description thereof will be provided with reference to  FIG. 2 . 
       FIG. 2  is a cross-sectional view of a light emitting region of an organic light emitting display according to an embodiment of the present invention. With reference to  FIG. 2 , the light emitting region of the organic light emitting display includes a transparent substrate  150  and a seal substrate  200  sealing the transparent substrate  150 . Accordingly, the light emitting region can display images to be viewed by a viewer. 
     A buffer layer  101  is formed on the glass  100  of the transparent substrate  150  and a semiconductor layer  102  is formed on the upper surface of the buffer layer  101 . An insulation layer  103  is formed on the upper surface of the semiconductor layer  102 , and a gate electrode  104  is formed by forming and patterning a metal layer on the upper surface of the insulation layer  103 . An ion doping process is performed on the semiconductor layer  102 . 
     An insulation layer  105  is formed on the upper surface of gate electrode  104  and then a contact hole  115  is formed in the insulation layer. A source drain metal  106  is formed by forming and patterning the metal layer on the upper surface of the semiconductor layer  102 . The source drain metal  106  may contact both ends of the semiconductor layer  102  through the contact hole  115 . 
     The insulation layer  107  is formed to have a flattened upper surface. A contact hole  117  is then formed in the insulation layer  107 , and the anode electrode  111  is formed on the insulation layer  107 . The anode electrode  111  contacts the source drain metal  106  through the contact hole  117 . 
     The insulation layer is formed on the anode electrode  111 . The insulation layer becomes PDL layer  108  and an impact absorbing layer by means of an etching of the insulation layer. The PDL layer  108  is a film defining region in which an organic light emitting diode is formed. The anode electrode  111  is exposed to the inside of the PDL layer  108 . The emission layer (not shown) is formed on the upper surface of anode electrode  111  and a cathode electrode is formed on the upper of thereof to form the organic light emitting diode. 
     The impact absorbing layer  109  and the PDL layer  108  are formed to be spaced from each other. Therefore, although an impact may be applied to the impact absorbing layer  109 , it is not transferred to the PDL layer  108 . In other words, although force generated by the impact from the outside is applied to the impact absorbing layer  109 , the force is not transferred to the emission layer formed on the PDL layer  108 . 
     The spacer  110  is formed on the upper of the impact absorbing layer to maintain the distance between the transparent substrate  150  and the seal substrate  200 . At this time, the spacer  110  can be formed to contact the seal substrate  200  and can be formed to be spaced at a distance therefrom. If the impact is applied from the outside, the impact is applied to the spacer  110 . As such, the impact applied to the spacer  110  is transferred to only the impact absorbing layer  109 , thereby protecting the emission layer. 
     The transparent substrate  150  and seal substrate  200  of the organic light emitting display may be adhered to each other by means of epoxy or frit, among other fasteners or adherents. An inert gas such as N2 is injected to a space between the transparent substrate  150  and the seal substrate  200 . 
     Also, in order to further increase the device strength, various reinforcing materials such organic materials, etc. are formed between the transparent substrate  150  and the seal substrate  200 . 
     As mentioned above, with the organic light emitting display and the method for making the same according to embodiments of present invention, the impact absorbing layer  109  is formed so as to be spaced from the PDL layer  108 , and the spacer  110  is formed on the impact absorbing layer  109 , making it possible to prevent damage to the organic light emitting diode due to the impact applied from the outside. 
     While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements include within the spirit and scope of the appended claims, and equivalents thereof.