Patent Publication Number: US-2006005380-A1

Title: Apparatus for arrange spacer of a field-emission display

Description:
BACKGROUND OF THE INVENTION  
      The present invention relates in general to an apparatus for installing a spacer of a field-emission display, and more particularly, to an apparatus operative to provide suction force normal to the spacer, such that the spacer can be disposed between the anode and cathode boards and aligned therewith. Further, the apparatus uses a vacuum breaking device to prevent electrostatic charges from be generated, particularly during the removal of the spacer from the apparatus.  
      Currently, the bipolar, tripolar or tetrapolar field emission displays all contain a spacer  10  between the cathode and anode boards (as shown in  FIGS. 1 and 2 ). The spacer  10  is designed to enhance the luminescent efficiency without overly reducing the breakdown voltage between the cathode and anode boards. Therefore, the space between the cathode and anode boards is typically maintained no smaller than 500 microns by the space  10 . Therefore, the spacer  10  has to be strong enough to withstand the atmosphere pressure. At the same time, the spacer has to possess specific aspect ratio such that it is not visible to naked eyes. Normally, the width for the spacer  10  is about 500 to 100 micron, the height of the spacer  10  is between 800 and 2000 microns, and the length of the spacer  10  is about 2 to 4 millimeters. The shapes include cross and stripes. Those spacers selected from sodalime or similar material all experience of brittle, difficult to retrieve and align, and the complex fabrication.  
      The conventional installation of the spacer  10  includes a side suction method as shown in  FIGS. 3 and 4 . As shown, the clamp-type suction mechanism  30  is used to suck the spacer  10  at the side thereof. A CCD can be used to assist alignment. The drawback is than the side-suction results in a transverse reaction to display the spacer  10  when the spacer is removed from the suction mechanism. Further, as the material of the spacer easily generate electrostatic charges, particularly during removal of the spacer  10  from the suction mechanism, the spacer is difficult to be removed.  
     BRIEF SUMMARY OF THE INVENTION  
      An apparatus for installing a spacer of a field-emission display is provided with a suction mechanism for sucking the spacer. The suction mechanism has a suction terminal, which an opening to apply suction force on top of the spacer and a positioning part located on top of the suction terminal for positioning the spacer sucked by the suction terminal. The suction terminal includes a pipe having a diameter smaller than that of the spacer. The positioning part is configured according to a configuration of the spacer. The opening has a uniform cross section from a bottom edge to a top surface thereof or a cross section gradually decreasing from a bottom edge to a top surface thereof.  
      An apparatus for installing a spacer of a field-emission display is further provided with a support member and a suction mechanism mounted to the support member. One end of the suction mechanism has an opening for applying a suction force to the spacer and a positioning part formed on the opening. The apparatus further has a gas transmission device.  
      An apparatus for installing a spacer of a field-emission display is also provided having a support member, a suction mechanism and a vacuum breaking device. One end of the suction mechanism is connected to the support member, and the other end of the suction mechanism has an opening for sucking the top portion of the spacer and a positioning part for aligning the spacer. The vacuum breaking device to provide an electrostatic removal gas to prevent electrostatic charges generated between the spacer and the suction mechanism. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The above objects and advantages of the present invention will be become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:  
       FIG. 1  shows the spacer used in the conventional field-emission display;  
       FIG. 2  shows another type of spacer used in the conventional field-emission display;  
       FIG. 3  is a top view of the conventional side-suction mechanism;  
       FIG. 4  is the side view showing the conventional side-suction mechanism;  
       FIG. 5  shows an apparatus for installing a spacer;  
       FIG. 6  is a rear view for a suction mechanism;  
       FIG. 7  shows the side view of the suction mechanism and the spacer;  
       FIG. 8  shows the top view of the suction mechanism and the spacer;  
       FIG. 9  shows the installment of the spacer;  
       FIG. 10  shows the side view of the suction mechanism; and  
       FIG. 11  shows another side view of the suction mechanism. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       FIGS. 5 and 6  shows the rear view of an apparatus for installing a spacer and a suction structure. As shown, the apparatus for installing the spacer of a field-emission display uses suction force generated by the suction structure to suck the spacer  10  as shown in  FIGS. 1 and 2 . The spacer  10  is then installed between the anode board (not shown) and the cathode board (not shown) of the field-emission display. Thereby, the luminescent efficiency of the phosphor on the anode is enhanced, and the breakdown voltage between the anode board and the cathode board will not be too low to affect the image.  
      The suction structure includes support element  11  mounted to an installation device  1 , a gas transmission device  12  connected to the suction structure  10  for venting the gas sucked by the suction structure  10 , a suction mechanism, which includes a suction terminal and a suction opening  22  facing downwardly. A positioning part  23  for positioning or holding the spacer  10  sucked by the suction structure is formed on top of the suction terminal  22 . The arrangement and configuration of positioning part  23  is variable according to the configuration of the spacer  10 . The gauge of the suction mechanism  2  can be smaller than the spacer  10 , such that the suction terminal  22  is operative to suck the spacer  10 .  
       FIGS. 7-9  illustrate the side view, top view and installing status of the suction mechanism and the spacer. As shown, when the spacer  10  is attached to the suction terminal  21  of the suction mechanism  2 , the spacer  10  is directly positioned within the positioning part  23 . Meanwhile, the operator uses the CCD lens to view from the top, the edges of the spacer  10  can be observed for alignment with the anode board  20 . When the spacer  10  and the anode board  20  are aligned with each other, the suction mechanism  2  is pressed downwardly by the installation apparatus, while the spacer  10  is lightly pressed to attach the anode board  20  by glass glue or paste (not shown).  
      In the process of sucking the spacer  10  by the suction mechanism, a vacuum breaking apparatus is used. The vacuum breaking apparatus provides an electrostatic removing gas, such that no electrostatic charge is generated during the suction process between the suction mechanism  2  and the spacer  10 . The spacer  10  being sucked can then be detached from the suction mechanism  2  easily, and the installing action of the next spacer  10  can be taken action.  
      Further, the internal diameter of the positioning part  23  of the suctioning mechanism  2  allows the opening  231  having a constant diameter from the opening edge to the top surface thereof as shown in  FIG. 10 . Alternatively, the opening  231  is gradually contracted as shown in  FIG. 11 , such that the diameter of the opening is gradually reduced from the bottom edge to the top surface thereof. When the suction mechanism  2  sucks the spacer  10  thereto, the spacer  10  can be directly positioned on the positioning part, such that it is advantageous to install the spacer  10  on the anode board  20 .  
      The embodiment as described above directly sucks the spacer and aligns the spacer  10  with the anode  20  via a CCD. Therefore, the labor and process for installing the spacer  10  are much reduced and simplify. Further, with the positioning part  23  formed on the suction mechanism  2 , the suction mechanism is self-aligned with the spacer  10  while sucking the spacer. Therefore, repetitive alignment schedule is not required. Further, as the spacer  10  and the anode board  20  are pressed against, the attachment is more reliable, and the amount of glue can be reduced to prevent overflow of the glue which may very likely affect the vision area.  
      While the present invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those of ordinary skill in the art the various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.