Abstract:
The testing method of OLED panels for all pixels on are provided. The methods include positioning anisotropic conductive films and conductive plates over a set of exposed first electrodes and a set of exposed second electrodes. Through the anisotropic conductive film and the conductive plate, the set of first electrodes and the set of second electrodes conduct. Thereafter, the set of first electrodes is connected to a first voltage and the set of second electrodes is connected to a second voltage. Through the voltage difference between the first voltage and the second voltage, all the inside the OLED panels are lit to perform the test.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the priority benefit of Taiwan application serial no.90130874, filed on Dec. 13, 2001. 
     BACKGROUND OF INVENTION 
     1. Field of Invention 
     The present invention relates to testing methods of organic light emitting diode (OLED) panels for all pixels on. More particularly, the present invention relates to testing methods of using an anisotropic conductive film (ACF) together with a conductive plate timing control to carry out all pixels testing on organic light emitting diode (OLED) panels. 
     2. Description of Related Art 
     An organic light emitting diode (OLED) panel is usually tested using two major methods. One method of testing the OLED panel is to scan the panel using a system containing a driving chip and a control circuit board to scan the panel. The other method is to spread a layer of silver paste over the electrodes of an OLED panel so that the panel is globally driven because all the diode units are connected. If a driving chip is used to conduct a panel test, different driving chip and control circuit board must be used for a panel having different pixel size and pitch. Hence, considerable investment must be made in the design and development of a suitable driving chip to conduct the test. Moreover, a driving chip can hardly sustain a high current or a high voltage and hence the current and voltage that the driving chip can provide to test the panel is quite limited. In addition, the number of panel that can be tested at any one time is also limited by the chip-controlled circuit board. 
     On the other hand, spreading silver paste to render all the diode units inside the OLED panel connected often leads to other problems. Non-uniformity of the silver paste may lead to some unlit pixels. Moreover, in high temperature or high humidity test, the coated silver paste may peel off leading to a direct effect on the test panel. 
     Furthermore, if the silver paste is spread non-uniformly, current and voltage may concentrate on a few electrodes. Ultimately, a portion of the pixels on the panel may be damaged after the testing. 
     SUMMARY OF INVENTION 
     Accordingly, one object of the present invention is to provide testing methods of organic light emitting diode (OLED) panels for all pixels on that utilizes an anisotropic conductive film together with a conductive plate to light up all the diodes inside the panels. 
     To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides testing methods of OLED panels for all pixels on. The methods include positioning anisotropic conductive films and conductive plates over a set of exposed first electrodes and a set of exposed second electrodes. Through the anisotropic conductive film and the conductive plate, the set of first electrodes and the set of second electrodes conduct. Thereafter, the set of first electrodes is connected to a first voltage and the set of second electrodes is connected to a second voltage. Through the voltage difference between the first voltage and the second voltage, all the pixels inside the OLEO panels are lit to perform the test. 
     In the testing methods of OLED panels for all pixels on of this invention, the conductive plate can be fabricated from any good conductor such as a copper foil. The first voltage and the second voltage can be provided through a power supplier. In addition, glue may be applied to the edge of the conductive plate to fix the conductive plate after bonding the conductive plate onto the anisotropic conductive film. 
     Furthermore, the testing methods of OLED panels for all pixels on according to this invention permits the concurrent testing of a plurality of OLED panels. To carry out concurrent testing of multiple OLED panels, a conductive plate is used to connect serially all the first electrodes of the OLED panels or a conductive plate is used to connect serially all the second electrodes of the OLED panels. Alternatively, a first conductive plate is used to connect serially all the first electrodes while a second conductive plate is used to connect serially all the second electrodes of the OLED panels. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     The accompanying drawings are included to provide a further understanding of the Invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings, 
     FIGS. 1 to  3  are top views showing the steps for carrying out the testing of an OLED panel through anisotropic conductive films and conductive plates according to a first embodiment of this invention; 
     FIG. 4 is a cross-sectional view of FIG. 3; 
     FIGS. 5 to  7  are top views showing the steps for carrying out the testing of an OLED panel through anisotropic conductive films and conductive plates according to a second embodiment of this invention; 
     FIG. 8 is a cross-sectional view of FIG. 7; and 
     FIGS. 9 and 10 are-top views showing two configurations for carrying out the testing of a plurality of OLED panels concurrently according to a third preferred embodiment of this invention. 
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated In the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. 
     FIGS. 1 to  3  are top views showing the steps for carrying out the testing of an organic light emitting diode (OLED) panel through anisotropic conductive films and conductive plates according to a first embodiment of this invention. As shown in FIG. 1, an organic light emitting diode (OLED) panel  100  is provided. The OLED panel  100  has a display region  102  and a non-display region  101 . The non-display region  101  has a plurality of first electrodes  104  and a plurality of second electrodes  106 . Both the first electrodes  104  and the second electrodes  106  extend from the display region  102 . The set of first electrodes  104  and the set of second electrodes  106  are perpendicularly attached to the OLED panel  100 . A light-emitting layer is positioned between the first electrodes  104  and the second electrodes  106 . Through the application of a voltage to the first electrodes  104  and the second electrodes  106 , the light-emitting layer is powered up to emit light so that images are displayed on the panel. 
     To test the OLED panel  100 , an anisotropic conductive film (ACF)  108  is placed over the first set of electrodes  104  and the second set of electrodes  106  respectively as shown in FIG.  2 . 
     As shown in FIGS. 3 and 4, where FIG. 4 is a cross-sectional view of FIG. 3, a first conductive plate  110   a  and a second conductive plate  110   b  made from a highly conductive material such as copper foil are provided. The conductive plates  110   a  and  110   b  are placed over the respective anisotropic conductive film  108 . Thereafter, pressure and heat are applied so that the conductive plates  110   a  and  110   b  are electrically connected to the first electrodes  104  and the second electrodes  106  through conductive particles within the anisotropic conductive films  108 . 
     The conductive plate  110   a  renders all the first electrodes  104  conductive and the conductive plate  110 b renders all the second electrodes  106  conductive. Furthermore, the first conductive plate  110   a  and the second conductive plate  110   b  may be connected to a power supplier  114 . The power supplier  114  supplies a first voltage V1 to the first conductive plate  110   a  and a second voltage V2 to the second conductive plate  110   b . Since all the first electrodes  104  and the second electrodes  106  are electrically connected to the first conductive plate  110   a  and the second conductive plate  110   b  respectively, all the diodes within the OLED panel  100  are powered to perform the test. 
     FIGS. 5 to  7  are top views showing the steps for carrying out the testing of an OLED panel through anisotropic conductive films and conductive plates according to a second embodiment of this invention. As shown in FIG. 5, an organic light emitting diode (OLED) panel  100  is provided. The OLED panel  100  has a display region  102  and a non-display region  101 . The non-display region  101  has a plurality of first electrodes  104  and a plurality of second electrodes  106 . Both the first electrodes  104  and the second electrodes  106  extend from the display region  102 . The set of first electrodes  104  and the set of second electrodes  106  are perpendicularly attached to the OLED panel  100 . A light-emitting layer is positioned between the first electrodes  104  and the second electrodes  106 . Through the application of a voltage to the first electrodes  104  and the second electrodes  106 , the light-emitting layer is powered up to emit light so that images are displayed on the panel. 
     To test the OLED panel  100 , an anisotropic conductive film (ACF)  108  is placed over the first set of electrodes  104  and the second set of electrodes  106  respectively as shown in FIG.  6 . 
     As shown in FIGS. 7 and 8, where FIG. 8 is a cross-sectional view of FIG. 7, a first conductive plate  110   a  and a second conductive plate  110   b  made from a highly conductive material such as copper foil are provided. The conductive plates  110   a  and  110   b  are placed over the respective anisotropic conductive film  108 . Thereafter, pressure and heat are applied so that the conductive plates  110   a  and  110   b  are electrically connected to the first electrodes  104  and the second electrodes  106  through conductive particles within the anisotropic conductive films  108 . Adhesive glue  112  is applied to the edges of the conductive plates  110   a  and  110   b  so that both conductive plates  110   a  and  110   b  are stationed on the panel. The adhesive glue  112  can be silicone glue, for example. The application of adhesive glue  112  prevents the conductive plates  110   a  and  110   b  from peeling off the OLED electrodes. 
     The conductive plate  110   a  renders all the first electrodes  104  conductive and the conductive plate  110   b  renders all the second electrodes  106  conductive. Furthermore, the first conductive plate  110   a  and the second conductive plate  110   b  may be connected to a power supplier  114 . The power supplier  114  supplies a first voltage V1 to the first conductive plate  110   a  and a second voltage V2 to the second conductive plate  110   b . Since all the first electrodes  104  and the second electrodes  106  are electrically connected to the first conductive plate  110   a  and the second conductive plate  110   b  respectively, all the diodes within the OLED panel  100  are powered to perform the test. 
     FIGS. 9 and 10 are top views showing two configurations for carrying out the testing of a plurality of OLED panels concurrently according to a third preferred embodiment of this invention. When a plurality of OLED panels  100  are lined up as shown in FIG. 9 for a concurrent test, a common conductive plate  110   b  connects all the second electrodes  106 . An alternative alignment of the OLED panels  100  is shown in FIG.  10 . Here, a common conductive plate  110   a  connects all the first electrodes  104  together. 
     The arrangement of OLED panels  100  in FIGS. 9 and 10 is able to withstand very high current and voltage. Hence, there is little problem is conducting the testing. 
     The second electrodes  106  of a plurality of OLED panels  100  are serially connected together through the conductive plate  110   b  as shown in FIG.  9 . Meanwhile, the first electrodes  104  of a plurality of OLED panels  100  are serially connected together through the conductive plate  110   a  as shown in FIG.  10 . This invention also permits a conductive plate  110   a  to connect all the first electrodes  104  of the OLED panels  100  and a conductive plate  110   b  to connect all the second electrodes  106  of the OLED panels  100 . 
     The advantages of using the anisotropic conductive films, the conductive plates and the fastening glue (selectively) to prepare for the test can be compared with a conventional arrangement in Table 1. 
     
       
         
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                 According to this 
                   
                   
               
               
                 Items 
                 Invention 
                 Driving Chip 
                 Silver Paste Coating 
               
               
                   
               
             
             
               
                 Cost 
                 Low cost 
                 Expensive to 
                 Cost is intermediate 
               
               
                 factor 
                   
                 develop and 
                 between the driving 
               
               
                   
                   
                 fabricate 
                 chip method and the 
               
               
                   
                   
                   
                 invention. 
               
               
                 Time 
                 Any time after 
                 Longer development 
                 Any time after 
               
               
                 factor 
                 wiring 
                 period 
                 wiring 
               
               
                 Environ- 
                 Not affected by 
                 Driving chip easily 
                 Coverage and 
               
               
                 mental 
                 environmental 
                 affected by 
                 reactance influenced 
               
               
                 factor 
                 temperature and 
                 environmental 
                 by environmental 
               
               
                   
                 humidity 
                 temperature and 
                 temperature, 
               
               
                   
                   
                 humidity 
                 humidity 
               
               
                 Testing 
                 Highly accurate 
                 Driving chip signal 
                 Error prone due to 
               
               
                 accuracy 
                   
                 easily interfered by 
                 poor display effect 
               
               
                   
                   
                 environmental 
               
               
                   
                   
                 factors 
               
               
                 Effect 
                 Display is good 
                 Display is good. 
                 Display is poor. 
               
               
                 of Display 
               
               
                   
               
             
          
         
       
     
     In summary, the testing methods of OLED panels for all pixels on according to this invention has the following advantages: 
     1. Using anisotropic conductive films together with conductive plates to connect up all the diodes inside the panel permits the flow of a larger current or the use of a higher voltage during the testing. 
     2. A testing of a multiple of OLED panels can be carried out through serial or parallel current connection. 
     3. The anisotropic conductive films are prevented from peeling off from the panel during testing through the application of some fastening glue. 
     4. The OLED panel test can be carried out at all sorts of temperature and humidity environment without much adverse effect. 
     5. Cost of carrying out the test of OLED panels are considerably lower than the conventional methods such as the driving chip or the silver paste coating method. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.