Abstract:
A plasma display device includes a plasma display panel, a chassis base coupled to the plasma display panel, a drive circuit coupled to the chassis base, a flexible printed circuit (FPC) couples the drive circuit to electrodes of the plasma display panel. An integrated circuit (IC) is mounted on a film structured in the form of a tape carrier package (TCP), and coupled to the FPC. An epoxy resin deposited in a connecting region where the driver IC is connected to wiring of the FPC is formed with an uneven area that includes indentations and protrusions formed substantially uniformly.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority to and the benefit of Korean Patent Application No. 10-2003-0084505, filed on Nov. 26, 2003, which is hereby incorporated by reference for all purposes as if fully set forth herein.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a plasma display device, and more particularly, to a plasma display device formed without an air gap in a connecting region of a tape carrier package (TCP) driver integrated circuit (IC). The present invention relates also to a method for manufacturing the TCP.  
         [0004]     2. Discussion of the Background  
         [0005]     Generally, a plasma display device displays images using plasma generated by a gas discharge. A flexible printed circuit (FPC) is typically used to couple display panel electrodes to a drive circuit. An IC may be formed on the FPC for selectively generating a wall voltage in pixels according to signals controlled in the drive circuit.  
         [0006]     ICs formed on FPCs are widely used for applying voltages, and they may be formed on the FPC using a variety of known techniques, such as the chip on board (COB) and chip on film (COF) assembly methods. Tape carrier packages (TCPs) are becoming more popular because of the small sizes that may be achieved with them, as well as their low cost.  
         [0007]     A TCP is a semiconductor chip packaging format utilizing tape automated bonding (TAB) tape. The TAB technology refers to the process of mounting and coupling a driver IC on the TAB tape&#39;s copper beam leads.  
         [0008]     The TAB tape typically has circuit wiring patterned on a polyimide tape, and the beam leads are connected to the circuit wiring and exposed in a window region where the driver IC is positioned. A solder register layer protects the circuit wiring.  
         [0009]     The TAB tape beam leads are coupled to a bump formed on a chip pad of the driver IC, thereby maintaining electrical and physical connections between the two. Further, an epoxy resin potting protects the driver IC from the external environment.  
         [0010]     Thermal grease may be applied between the driver IC and a chassis base, or between the driver IC and a reinforcing member on the chassis base, so that heat may be quickly dissipated from the driver IC. A heat dissipating plate may also be mounted at an outer surface of the driver IC to emit heat to the outside.  
         [0011]     However, the conventional TCP driver IC is not without problems. In particular, since an epoxy resin is deposited on a copper film of the FPC and a connecting section of the driver IC (i.e., a rear surface of the driver IC), once dried, a center area of the epoxy resin may have a depressed formation. This depressed formation may permit formation of a layer of air in the area when the depositing surface of the epoxy resin adheres to the chassis base or reinforcing member. This air gap reduces the driver IC&#39;s heat dissipating efficiency.  
         [0012]     Furthermore, thermal grease is often applied to the deposition surface of the epoxy resin in order to reduce heat resistance caused by the air gap. In this case, the thermal grease may be forced outward from the epoxy resin when the driver IC is subsequently pressed onto the chassis base or reinforcing member. If the driver IC is removed and re-attached during assembly, the thermal grease may be depressed and therefore unable to fill the center area of the epoxy resin. Consequently, even when using the thermal grease, the epoxy resin&#39;s depressed formation and the layer of air may remain.  
         [0013]     The air gap may permit excessive accumulation of heat generated by the TCP driver IC, thereby causing the TCP driver IC to breakdown and, in extreme cases, burst.  
       SUMMARY OF THE INVENTION  
       [0014]     The present invention provides a driver IC with an improved capability to dissipate heat through an improved epoxy resin deposition structure.  
         [0015]     The present invention also provides a TCP of a plasma display device that may prevent the formation of an air gap and insufficient filling of thermal grease during a device&#39;s attachment and re-attachment to a chassis base or reinforcing member.  
         [0016]     Additional features of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention.  
         [0017]     The present invention discloses a plasma display device comprising a plasma display panel, a chassis base coupled to the plasma display panel, a drive circuit coupled to the chassis base, a flexible printed circuit (FPC) coupling the drive circuit and the plasma display panel, and an integrated circuit (IC) coupled to the FPC. An epoxy resin is deposited in a coupling region where the IC is coupled to the FPC, and the epoxy resin has a surface comprising an indentation and a protrusion.  
         [0018]     The present invention also discloses a tape carrier package comprising a flexible printed circuit (FPC) having a beam lead extending into a window area of the FPC, an integrated circuit (IC) coupled to the beam lead, and an epoxy resin in the window area of the FPC to protect the IC and the beam lead. The indentations and protrusions are formed on an outer surface of the epoxy resin.  
         [0019]     The present invention also discloses a method for manufacturing a tape carrier package having an integrated circuit (IC) mounted on a film that is bonded using a tape carrier process. The method includes connecting an inner beam lead formed on a flexible printed circuit and a bump of the IC by a process of thermo-compression bonding, depositing an epoxy resin in an area of connection between the beam lead and the IC, forming an uneven area comprising indentations and protrusions in an outer surface of the epoxy resin, and curing the epoxy resin.  
         [0020]     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.  
         [0022]      FIG. 1  is a perspective view of a plasma display device according to an exemplary embodiment of the present invention.  
         [0023]      FIG. 2  is a partially exploded perspective view of the plasma display device of  FIG. 1 .  
         [0024]      FIG. 3  is front view of a structure of an epoxy resin deposited on a driver IC of  FIG. 2 .  
         [0025]      FIG. 4  is a sectional view taken along line A-A of  FIG. 2 . 
     
    
     DETAILED DESCRIPTION  
       [0026]     An exemplary embodiment of the present invention will now be described in detail with reference to the drawings.  
         [0027]      FIG. 1  is a perspective view of a plasma display device according to an exemplary embodiment of the present invention,  FIG. 2  is a partially exploded perspective view of the plasma display device of  FIG. 1 ,  FIG. 3  is front view of a structure of an epoxy resin deposited on a driver IC of  FIG. 2 , and  FIG. 4  is a sectional view taken along line A-A of  FIG. 2 .  
         [0028]     Referring to  FIG. 1 ,  FIG. 2 ,  FIG. 3  and  FIG. 4 , a plasma display device according to an exemplary embodiment of the present invention includes a plasma display panel (“panel”)  12  and a chassis base  16 . The panel  12  and the chassis base  16  each have a substantially rectangular, planar shape with opposing inner and outer surfaces. The panel  12  is mounted substantially parallel to the chassis base  16  such that their inner surfaces are adjacent to one another. Drive circuits  18  may be mounted on an outer surface of the chassis base  16 . A thermal conducting medium (not shown) may be interposed between the panel  12  and the chassis base  16 . A front cover (not shown) is positioned at the outer surface of the panel  12 , and a back cover (not shown) is positioned at the outer surface of the chassis base  16 . The front cover is connected to the back cover to house the plasma display device.  
         [0029]     Electrodes of the panel  12  may be coupled to the drive circuits  18  through FPCs  21  to thereby receive signals required for operation. Specifically, driver ICs  23  on the FPCs  21  may selectively apply voltages to the electrodes of the panel  12  according to signals controlled by the drive circuits  18 . In an exemplary embodiment of the present invention, the driver ICs  23  may be packaged in TCPs  25  for coupling to the FPCs  21  and the drive circuits  18 .  
         [0030]     Further, the driver ICs  23  may be positioned on an optional reinforcing member  28 , which may be mounted to the chassis base  16 , and a heat dissipating plate  29  may cover the TCPs  25 . The heat dissipating plate  29  may contact an outer surface of the driver IC  23  and press the driver IC  23  toward the reinforcing member  28 . Additionally, the heat dissipating plate  29  dissipates heat generated by the driver IC  23 . A thermal conductor  35  may be interposed between the heat dissipating plate  29  and the driver IC  23 .  
         [0031]     Each heat dissipating plate  29  includes a first surface  29   a,  which covers the driver ICs  23  and has upper and lower ends, and a second surface  29   b,  which extends from the lower end of the first surface  29   a  in a direction toward the panel  12  until reaching an outer surface thereof, thereby acting as a support for the FPCs  21 . The heat dissipating plate  29  may be made of a conductive material such as aluminum, copper, or steel, and it is fixed to the chassis base  16  through connectors (not shown).  
         [0032]     An epoxy resin  30  is deposited in a connecting region between the FPCs  21  and the driver ICs  23 , and it covers a rear surface of each of the driver ICs  23 . An outer surface of the epoxy resin  30  may contact the reinforcing member  28 , and it may be formed with indentations and protrusions to thereby form an uneven region  40 , as shown in  FIG. 3  and  FIG. 4 . A depth of the indentations may be 0.1 mm or greater.  
         [0033]     Each of the TCPs  25  may have a structure in which at least one of the driver ICs  23  is mounted on the corresponding FPC  21 . An upper end of the TCPs  25  may be coupled to a corresponding drive circuit  18 , and a lower end may be coupled to the panel  12 . Further, the epoxy resin  30  may be deposited in the connecting region of the driver ICs  23 , as described above, and the uneven region  40  may be formed having protrusions and indentations that are substantially uniformly distributed thereon.  
         [0034]     The TCPs  25 , the driver ICs  23 , and the connecting structure between the TCPs  25  and the chassis base  16  will be described in greater detail with reference to  FIG. 4 . The connections associated with only one of the driver ICs  23  will be described in the following by way of example to illustrate such connections for all of the driver ICs  23 .  
         [0035]     In the TCP  25 , a beam lead  31  is formed in a circuit pattern, and a solder register layer  32  protects the FPC  21 . The beam lead  31  extends into a window area defined by the FPC  21 , and a bump  33  is interposed between the beam lead  31  and the driver IC  23 . The epoxy resin  30  is deposited and cured in the window area, and it protects the extended portion of the beam lead  31  and the driver IC  23 . The uneven region  40  may be formed on an outer surface of the epoxy resin  30 .  
         [0036]     The uneven region  40  may contact the reinforcing member  28 , which may be optionally mounted on the chassis base  16 , and a thermal grease  45  may be applied between the contacting surfaces of the uneven region  40  and the reinforcing member  28 . The heat dissipating plate  29  may be positioned to cover a side of the driver IC  23  away from the epoxy resin  30 . As noted above, a thermal conductor  35  may be interposed between the heat dissipating plate  29  and the driver IC  23 .  
         [0037]     Manufacturing the TCP  25  will now be described. First, a copper film is attached to a thick polyimide film (75 μm or greater) to produce an FPC with a desired circuit pattern. Next, a bump of a driver IC is thermally compressed onto a portion of a beam lead extending into a window area of the FPC. An epoxy resin is deposited in the window area to cover the extended portion of the beam lead and an adjacent area of the driver IC. An uneven region is formed on a surface of the epoxy resin away from the driver IC before the epoxy resin is fully cured. The uneven region may be formed such that protrusions and indentations are uniformly present on the surface of the epoxy resin. The epoxy resin is then cured.  
         [0038]     Following curing, an electrical test, and marking and printing processes, may be performed. Since these subsequent processes are well known to those skilled in the art, a detailed description thereof will not be provided herein.  
         [0039]     The uneven region  40  of the epoxy resin  30  may provide specific benefits. Namely, when the driver IC  23  is pressed toward the reinforcing member  28 , the thermal grease  45  deposited between the reinforcing member  28  and the epoxy resin  30 , as described above, may be forced into the indentations of the uneven region  40 , and the amount of the thermal grease  45  forced outward and away from the area of the epoxy resin  30  may be minimized. This may prevent the formation of an air gap between the reinforcing member  28  and the epoxy resin  30 .  
         [0040]     Further, when re-installing the driver IC  23  after removing it, the thermal grease  45  in the indentations of the uneven area  40  may remain therein. Therefore, an air gap may also be prevented from forming between the epoxy resin  30  and the reinforcing member  28  when the driver IC  23  is re-attached.  
         [0041]     It will be apparent to those skilled in the art that various modifications and Is variation can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.