Patent Publication Number: US-2005134557-A1

Title: ACF assembly apparatus and method

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates to an ACF (anisotropic conductive film) assembly apparatus and method, and in particular, to an ACF assembly method that ensures precise and reliable connection with a display panel.  
      2. Description of the Related Art  
      In recent years, a display panel, such as a liquid crystal display (LCD) panel, has been widely used instead of CRT.  
      The display panel has a display layer for performing display. The display layer is held between a pair of substrates, or is carried or held by a single substrate. In the liquid crystal display panel, the display layer is a liquid crystal layer, and is held between a pair of substrates.  
      In the display panel, transparent electrodes are formed on opposite sides of the display layer for changing the state of the display layer to perform display. For example, a voltage is applied across the electrodes to change the state of the display layer, so that the display is performed.  
      The electrode on at least one side is usually formed on the substrate provided for holding or carrying the display layer. The electrode on the substrate is usually electrically connected to a drive element (e.g., drive IC) of a drive device, and a control portion of the drive device applies a voltage via the drive element to the electrode for driving the display panel.  
      The drive element is mounted directly on the substrate of the display panel, and is usually directly connected to the electrode on the substrate. Specifically, a lead of the drive element may be connected to the electrode with an anisotropic conductive adhesive such as ACF while applying a heat and a pressure during the connecting operation.  
      Before the ACF is attached on the display panel, it is combined with a separator to form an adhesive member. The specific description of the conventional ACF assembly method is described in the following.  
      Referring to  FIG. 1A , a conventional ACF assembly apparatus  10  for a display panel  20  is described. The conventional ACF assembly apparatus  10  includes a press head  11 , a pair of first rollers  12 , a pair of second rollers  13 , a pair of third rollers  14 , a supply  15 , a recycling device  16 , and three sensors  17 .  
      The press head  11  is located above the adhesive member  30 , and applies the pressure to the adhesive member  30  during the connecting operation. Referring to  FIG. 1B , the adhesive member  30  includes ACF  31  and a separator  32 .  
      The adhesive member  30  passes between the first rollers  12  so that the separator  32  can be separated from the ACF  31  by the first rollers  12 . The second rollers  13  and the third rollers  14  guide the adhesive member  30  to move along a predetermined path. It is noted that the first rollers  12  and the second rollers  13  can move upward or downward during the connecting operation. The supply  15  provides the adhesive member  30 , and the recycling device  16  can hold and recycle the separated separator  32 .  
      The sensors  17  are fixedly located above an electrode area  21  of the display panel  20 , and detects whether or not the ACF  31  is precisely attached to the electrode area  21 .  
      To assemble the ACF  31  on the electrode area  21 , the adhesive member  30  is first aligned with the electrode area  21  of the display panel  20 . The press head  11 , the first rollers  12 , and the second rollers  13  along with the adhesive member  30  then move downward, and the press head  11  applies the pressure to the adhesive member  30  on the electrode area  21  so that the adhesive member  30  is attached to the electrode area  21 . The first rollers  12  moves to the left side from the right side, so as to separate the separator  32  from the ACF  31  remained on the display panel  20 . The first rollers  12  and the second rollers  13  then move upward, and the separated separator  32  is recycled by the recycling device  16 . The ACF  31  remained on display panel  20  is then detected by the fixed sensors  17 . If the ACF attachment fails due to the breakage of the ACF or others, the alarm is triggered and the assembly process halted.  
      It is understood that the display panel  20  includes two electrode areas  21  at two sides of the display panel  20  as shown in  FIG. 1A . Thus, the ACF assembly process may be performed twice on one display panel  20 .  
      The conventional ACF assembly method has the following disadvantage. As shown in  FIG. 1C , since the sensors  17  are fixed at a predetermined location, only specific areas A on the display panel  20  can be detected by the sensors  17 . Thus, other areas B cannot be detected by the sensors  17 . As a result, the entire ACF cannot be detected, and the yield of the display panel is accordingly reduced. Moreover, the cost due to rework is increased.  
     SUMMARY OF THE INVENTION  
      In view of this, the present invention provides an ACF assembly method and apparatus that ensures precise and reliable connection with a display panel.  
      Accordingly, the present invention provides an ACF assembly apparatus for a display panel. The ACF assembly apparatus includes a pressing device, a separating device, and a sensor. The pressing device attaches an adhesive member onto the display panel. The adhesive member includes ACF and a separator. The separating device is moveable relative to the display panel, and removes the separator from the ACF remained on the display panel. The sensor is disposed on the separating device and moves along with the separating device, and detects the ACF on the display panel.  
      In a preferred embodiment, the ACF assembly apparatus further includes a recycling device, a plurality of rollers, a controller, and a supply. The recycling device holds and recycles the removed separator. The rollers guide the adhesive member to move along a predetermined path. The controller is coupled to the sensor, and receives a signal from the sensor. The supply provides the adhesive member.  
      Furthermore, the pressing device is a press head. The separating device includes two rollers.  
      In the present invention, an ACF assembly method for a display panel is provided. The ACF assembly method includes the following steps. An adhesive member with ACF and a separator is provided. The adhesive member is then attached to the display panel. The separator is removed from the display panel while the ACF remained on the display panel is detected.  
      It is noted that the entire ACF on the display panel can be detected by a moveable sensor.  
      In another embodiment, the adhesive member is attached to the display panel by pressing. The separator is separated from the display panel by rollers. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:  
       FIG. 1A  is a schematic view of a conventional ACF assembly apparatus;  
       FIG. 1B  is a partial enlarged view of an adhesive member in  FIG. 1A ;  
       FIG. 1C  is a schematic view showing the relationship between a display panel and sensors in  FIG. 1A ;  
       FIG. 2A  is a schematic view of an ACF assembly apparatus as disclosed in the invention;  
       FIG. 2B  is a schematic view showing the relationship between a display panel and sensors in  FIG. 2A ; and  
       FIG. 3  is a flowchart of an ACF assembly method as disclosed in the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Referring to  FIGS. 2A-2B , an ACF assembly apparatus  110  as disclosed in the invention is shown. The ACF  10  assembly apparatus  110  serves to attach an adhesive member  30  onto a display panel  20 , and includes a pressing device  111 , a separating device  112 , a sensor  113 , a recycling device  114 , a pair of first rollers  115 , a pair of second rollers  116 , a supply  117 , and a controller  118 .  
      The pressing device  111  is located above the adhesive member  30 , and applies the pressure to the adhesive member  30  during assembly so as to attach the adhesive member  30  onto the display panel  20 . The pressing device  111  may be a press head.  
      The separating device  112  is moveable relative to the display panel  20 , and includes two rollers  112   a ,  112   b . The adhesive member  30  passes between the rollers  112   a ,  112   b  so that the separator  32  can be separated from the ACF  31  by the rollers  112   a ,  112   b  of the separating device  112 .  
      As shown in  FIG. 2B , the sensor  113  is disposed on the separating device  112 , and is moved along with the separating device  112 . The sensor  113  can detect whether or not the ACF  31  is precisely attached to the electrode area  21  of the display panel  20  while the separator  32  is separated by the separating device  112 .  
      The recycling device  114  can hold and recycle the removed separator  32 . The first rollers  115  and the second rollers  116  guide the adhesive member  30  to move along a predetermined path. It is noted that the separating device  112  and the first rollers  115  can move upward or downward during assembly.  
      The supply  117  provides the adhesive member  30 . The controller  118  is coupled to the sensor  113 , and receives a signal from the sensor  113 . If an abnormal situation is detected by the sensor  113 , the controller  118  will receive a fail signal from the sensor  113  and halt the assembly process after the separator  32  is separated entirely from the ACF  31  that attached on the display panel  20 .  
      The structure of the ACF assembly apparatus is described as above, and the ACF assembly method thereof is described in the following.  
      Referring to  FIG. 3 , in step S 11 , the adhesive member  30  is provided, and is aligned with the electrode area  21  of the display panel  20 . The pressing device  111 , the separating device  112 , and the first rollers  115  along with the adhesive member  30  then move downward. The pressing device  111  applies the pressure to the adhesive member  30  on the electrode area  21  so that the adhesive member  30  is attached to the electrode area  21  in step S 12 . In step S 13 , the separating device  112  moves to the left side from the right side so as to separate the separator  32  from the ACF  31  remained on the display panel  20 . At the same time, the sensor  113 , moving along with the separating device  112 , detects whether or not the ACF  31  is precisely attached to the electrode area  21  of the display panel  20 . If the ACF attachment is failed due to the breakage of the ACF or others, the sensor  113  will transmit a signal to the controller  118  so as to trigger the alarm and halt the assembly process after the separator  32  is separated entirely from the ACF  31  that attached on the display panel  20 . The separating device  112  and the first rollers  115  finally move upward, and the removed separator  32  is recycled by the recycling device  114 .  
      As stated above, by means of the moveable sensor, the entire ACF on the display panel can be detected. Thus, the yield can be enhanced.  
      While the invention has been described by way of example and in terms of the preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiment. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.