Abstract:
A plasma display apparatus includes a plasma display panel and a chassis base extending substantially parallel to the plasma display panel. The chassis base has a driving circuit mounted thereon in opposition to the plasma display panel. A driver IC faces the chassis base, and is packaged in a film-shaped assembly. A thermal conduction medium is disposed and solidified between the driver IC and the chassis base so as to dissipate the heat generated at the driver IC.

Description:
CLAIM OF PRIORITY  
       [0001]     This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. §119 from an application for PLASMA DISPLAY APPARATUS HAVING HEAT DISSIPATING STRUCTURE FOR DRIVER IC earlier filed in the Korean Intellectual Property Office on 23 Oct. 2003 and there duly assigned Serial No. 2003-74256.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a plasma display apparatus and, more particularly, to a plasma display apparatus having a heat dissipating structure for a driver integrated circuit (IC).  
         [0004]     2. Description of Related Art  
         [0005]     Generally, a plasma display apparatus has a plasma display panel for displaying the desired images based on the plasma generated due to gas discharge. The electrodes provided at the plasma display panel are electrically connected to a driving circuit, and a driver IC applies address voltages to the electrodes in accordance with the signals controlled at the driving circuit.  
         [0006]     Among voltage application structures using a driver IC, there are a chip on board (COB) structure wherein the driver IC is mounted on a printed circuit board (PCB), and a chip on film (COF) structure wherein the driver IC is directly mounted on a flexible printed circuit (FPC) formation film. Recently, a small-sized and low cost tape carrier package (TCP) has been extensively used as the voltage application structure.  
         [0007]     Meanwhile, in order to express 256 grays or more with a plasma display panel, at least eight-timed address discharges should be made for {fraction (1/60)} second corresponding to the one TV field, and hence, much heat is generated in the COF, the COB or the TCP structures mounted on the chassis base.  
         [0008]     Accordingly, a reinforcing plate is provided at the COB or the COF structure to reinforce its structural intensity and fix it to the chassis base. The reinforcing plate has the further role of a heat sink to dissipate the heat generated at the IC to the exterior.  
         [0009]     Meanwhile, in order to dissipate the heat generated at the driver IC of the TCP structure, a liquid or gel-typed thermal conduction medium is disposed between the driver IC and the chassis base to transfer the heat to the chassis base.  
         [0010]     However, with respect to the plasma display apparatus with the above heat dissipating structure, when it is checked or repaired, the thermal conduction medium is diffused toward the periphery of the driver IC to thereby form a predetermined gap between the driver IC and the chassis base. Accordingly, the heat conducted from the driver IC via the thermal conduction medium is not efficiently transferred to the chassis base due to the gap between the driver IC and the chassis base so that the heat at the driver IC is not dissipated.  
       SUMMARY OF THE INVENTION  
       [0011]     It is an object of the present invention to provide a plasma display apparatus which has a heat dissipating structure for a driver IC capable of enhancing the heat dissipating efficiency of the driver IC.  
         [0012]     This and other objects may be achieved by a plasma display apparatus with the following features.  
         [0013]     The plasma display apparatus includes a plasma display panel and a chassis base extending substantially parallel to the plasma display panel. The chassis base has a driving circuit mounted thereon in opposition to the plasma display panel. A driver IC faces the chassis base, and is packaged in a film-shaped assembly. A thermal conduction medium is disposed and solidified between the driver IC and the chassis base so as to dissipate the heat generated in the driver IC.  
         [0014]     The driver IC is preferably formed as a tape carrier package (TCP). The TCP packages the driver IC with a TCP tape, and electrically interconnects the plasma display panel and the driving circuit via the TCP tape.  
         [0015]     The thermal conduction medium has a heat dissipating structure for the driver IC and in contains a hardening epoxy resin.  
         [0016]     A subsidiary medium may fill the gap between the thermal conduction medium and the chassis base. The subsidiary medium has a heat dissipating structure for the driver IC and contains silicon oil or thermal grease.  
         [0017]     Alternatively, the subsidiary medium may contain a hardening epoxy resin, and is disposed and solidified between the thermal conduction medium and the chassis base.  
         [0018]     A compression plate may face the driver IC, and has a heat dissipating structure for the driver IC extending parallel to the chassis base.  
         [0019]     A thermal conduction medium may be disposed between the compression plate and the driver IC. The thermal conduction medium is in the form of a silicon sheet. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]     A more complete appreciation of the invention, and many of the attendant advantages thereof, will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference symbols indicate the same or similar components, wherein:  
         [0021]      FIG. 1  is an exploded perspective view of a plasma display apparatus according to a first embodiment of the present invention;  
         [0022]      FIG. 2  is a cross-sectional view of a heat dissipating structure for the driver IC of the plasma display apparatus according to the first embodiment of the present invention;  
         [0023]      FIG. 3  is a cross-sectional view of a heat dissipating structure for a driver IC of a plasma display apparatus according to a second embodiment of the present invention; and  
         [0024]      FIG. 4  is a cross-sectional view of a heat dissipating structure for a driver IC of a plasma display apparatus according to a third embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0025]     The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown.  
         [0026]      FIG. 1  is an exploded perspective view of a plasma display apparatus according to a first embodiment of the present invention, and  FIG. 2  is a cross-sectional view of a heat dissipating structure for the driver IC of the plasma display apparatus according to the first embodiment of the present invention.  
         [0027]     As shown in  FIG. 1 , the plasma display apparatus basically includes a plasma display panel  12  (referred to hereinafter simply as the “PDP”), and a chassis base  16 . The PDP  12  is mounted adjacent to the side surface of the chassis base  16 , and a driving circuit  18  is mounted at an opposite side surface of the chassis base  16 . The PDP  12  has a structure wherein electrodes for receiving the display signals are drawn from the periphery thereof. The electrodes are electrically connected to the driving circuit  18  via connectors  20  so as to receive the signals required for driving the PDP  12 .  
         [0028]     As seen in  FIG. 2 , the connector  20  is structured in the form of a TCP  25 . The TCP  25  has a TCP tape  21  electrically interconnecting the electrode of the PDP  12  and the driving circuit  18 , and a driver IC  23  mounted over the TCP tape  21 .  
         [0029]     The TCP tape  21  has a film-shaped FPC structure. The TCP tape  21  extends from the periphery of the PDP  12  to the periphery of the driving circuit  18  while passing through the chassis base  16  to electrically interconnect the electrode of the PDP  12  and the driving circuit  18 .  
         [0030]     The driver IC  23  is mounted over a hole  21   a  of the TCP tape  21  in the form of a package, and electrically interconnects the electrode of the PDP  12  and the driving circuit  18  via bumps  21   b . The driver IC  23  selectively applies a predetermined voltage to the electrode of the PDP  12  in accordance with control signals from the driving circuit  18 .  
         [0031]     A thermal conduction medium  31  is disposed between the driver IC  23  and the chassis base  16 . With the driving of the plasma display apparatus, the thermal conduction medium  31  transfers heat generated in the driver IC  23  to the chassis base  16 .  
         [0032]     With the heat dissipating structure for the driver IC  23  according to the first embodiment of the present invention, the thermal conduction medium  31  is disposed in the space between the driver IC  23  mounted over the hole  21   a  and the chassis base  16 , and is hardened so as to be in a solid state.  
         [0033]     The thermal conduction medium  31  is composed of a thermal compound containing a hardener, such as epoxy resin. The epoxy resin is hardened from the liquid state with a high viscosity so as to assume a solid state due to the hardener.  
         [0034]     With the above-structured plasma display apparatus, the thermal conduction medium  31  is disposed in the empty space between the driver IC  23  and the chassis base  16  in a liquid state, and is fitted to the chassis base  16 . When the plasma display apparatus is operated, the heat generated in the driver IC  23  is efficiently transferred to the chassis base  16  via the thermal conduction medium  31 . Since the thermal conduction medium  31  is in a solidly hardened state, it cannot disperse around the driver IC  23  when device checking or repairing is carried out.  
       EXAMPLE  
       [0035]     In relation to a 42-inch PDP module provided with a TCP, a thermal conduction medium composed of a hardening thermal conduction compound was formed between the chassis base and the driver IC (according to an embodiment of the present invention), and a thermal conduction member composed of a liquid or gel-typed liquid thermal conduction compound was formed between the chassis base and the driver IC (according to the prior art). The thermal conductivity of the hardening thermal conduction compound and the liquid thermal conduction compound, and the temperature of the IC part were measured, and compared.  
                                                                             TABLE 1                               First   Second   Third   Fourth   Fifth   Sixth           Liquid   hardening   hardening   hardening   hardening   hardening   hardening           thermal   thermal   thermal   thermal   thermal   thermal   thermal           conduction   conduction   conduction   conduction   conduction   conduction   conduction       Division   compound   compound   compound   compound   compound   compound   compound                                Thermal   0.1   0.84   0.92   1.59   1.92   0.83   1.34       conductivity       (W/m.k)       IC   58.7   58.4   58.2   57.4   56.1   58.1   56.6       temperature       (deg. C)                  
 
         [0036]     As shown in Table 1, the thermal conductivity of the thermal conduction medium based on the hardening thermal conduction compound was higher than that of the thermal conduction member based on the liquid thermal conduction compound, and the temperature of the driver IC in the former case was lower than that in the latter case. That is, with the thermal conduction medium formed between the driver IC and the chassis base while being hardened so as to be in a solid state, the heat generated in the driver IC can be transferred in an effective manner to the chassis base performing the role of a heat sink, thereby providing efficient heat dissipation.  
         [0037]     The hardening thermal conduction compounds listed in Table 1 are based on the products of the US company, Dow Corning.  
         [0038]     Meanwhile, when the thermal conduction medium  31  is hardened between the driver IC  23  and the chassis base  16 , it is liable to be distorted or shrunk so that a gap is formed at the interface between the thermal conduction medium  31  and the chassis base  16 .  
         [0039]     In this connection, with a plasma display apparatus according to a second embodiment of the present invention, as shown in  FIG. 3 , a subsidiary medium  41  is disposed between the thermal conduction medium  31  and the chassis base  16 .  
         [0040]     The subsidiary medium  41  is formed from a liquid or gel-type thermal conduction compound which contains silicon oil or thermal grease. The subsidiary medium  41  eliminates the gap between the solidly hardened thermal conduction medium  31  and the chassis base  16 , thereby enhancing the heat dissipating efficiency of the driver IC  23 .  
         [0041]     When the display apparatus is checked or repaired, the subsidiary medium  41  is liable to be dispersed toward the periphery of the driver IC  23  so that a predetermined gap may be formed between the thermal conduction medium  31  and the chassis base  16 .  
         [0042]     In this connection, with a plasma display apparatus according to a third embodiment of the present invention, as shown in  FIG. 4 , a subsidiary medium  51  composed of a hardening thermal conduction compound, similar to the thermal conduction medium  31 , is disposed between the solid thermal conduction medium  31  and the chassis base  16 .  
         [0043]     In this embodiment, the subsidiary medium  51  is disposed between the thermal conduction medium  31  and the chassis base  16  in a liquid state, and is hardened so as to be in a solid state, thereby completely eliminating the gap, and adhering the TCP  25  to the chassis base  16 .  
         [0044]     Therefore, the possibility of a gap between the driver IC  23  and the chassis base  16  is completely eliminated due to presence of the thermal conduction medium  31  and the subsidiary medium  51 , thereby enhancing the heat dissipating efficiency of the driver IC  23 .  
         [0045]     Meanwhile, as shown in FIGS.  1  to  4 , a compression plate  32  may be provided external to the driver IC  23  so as to compress the driver IC  23  against the chassis base  16 . The compression plate  32  is formed of aluminum, copper or iron, as is the case with the chassis base  16 . The compression plate  32  is fixed to the chassis base  16  via a coupling member, such as a screw. Furthermore, a thermal conduction medium  36  is disposed between the compression plate  32  and the driver IC  23 . The thermal conduction medium  36  transfers heat generated in the driver IC  23  to the compression plate  32 . A silicon sheet attached to the compression plate  32  may function as the thermal conduction medium  36 . Consequently, the heat generated in the driver IC  23  can be dissipated through the thermal conduction medium  36  and the compression plate  32 .  
         [0046]     As described above, with the plasma display apparatus having a heat dissipating structure for a driver IC, the gap between the driver IC and the chassis base is completely eliminated due to the thermal conduction medium composed of a hardening thermal conduction compound, thereby enhancing the heat dissipating efficiency of the driver IC and the reliability of the driver IC.  
         [0047]     Although preferred embodiments of the present invention have been described in detail hereinabove, it should be clearly understood that many variations and/or modifications of the basic inventive concept, which may appear to those skilled in the art, will still fall within the spirit and scope of the present invention, as defined in the appended claims.