Abstract:
A plasma display device for efficiently dissipating heat from a driver IC packaged in a form of a tape carrier package. The device includes a plasma display panel, a printed circuit board assembly, a chassis base having one surface attached to the plasma display panel and another surface adapted to mount the printed circuit board assembly thereon, a TCP (tape carrier package) adapted to electrically connect the printed circuit board assembly to an electrode leading out from the plasma display panel, a driver IC (integrated circuit) arranged on the TCP, the driver IC being adapted to generate and selectively apply a pulse to the electrode leading out from the plasma display panel, a chassis bed arranged at an edge of the chassis base, the chassis bed being adapted to support one side of the driver IC on the TCP, a cover plate adapted to cover another side of the driver IC on the TCP, the cover plate being further adapted to be opposingly arranged at the chassis bed and a heat sink arranged at an outer surface of the cover plate and arranged lengthwise with the cover plate, the heat sink comprising vertical and horizontal air passages.

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 A PLASMA DISPLAY DEVICE earlier filed in the Korean Intellectual Property Office on 16 Feb. 2005 and there duly assigned Serial No. 10-2005-0012657.  
       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 that efficiently dissipates heat from a driver IC packaged in a format of a tape carrier package (hereinafter, referred to as “TCP”).  
         [0004]     2. Description of the Related Art  
         [0005]     A plasma display device is an apparatus that displays an image on a plasma display panel (PDP) using plasma generated by a gas discharge. The plasma display device includes the PDP, a chassis base supporting the PDP, and a plurality of printed circuit board assemblies (PBAs). The PBAs are disposed at a side of the chassis base opposite to that of the PDP. The PBAs are electrically connected to display electrodes and address electrodes disposed within the PDP.  
         [0006]     In the plasma display device, an electrode printed on the PDP is generally electrically connected to a PBA through a flexible printed circuit (hereinafter, referred to as “FPC”). In other words, a discharge cell in the PDP is addressed by the address electrode and the display electrode provided within the PDP. A sustain discharge subsequently occurs in the addressed discharge cell to realize the image. In order to achieve these, the electrodes provided within the PDP lead out through the FPC and are connected to the PBAs and are thus controlled by the PBAs.  
         [0007]     The address electrode is connected to a PBA through a tape carrier package (TCP) that packages the driver IC. An address pulse is applied to the address electrode through the driver IC. In other words, in order to selectively form a wall voltage in a pixel of the PDP, the driver IC repeatedly applies an address pulse to a corresponding address electrode within a short period of time depending on a control signal received from a driving circuit.  
         [0008]     As a structure for applying voltage using the FPC and the driver IC, a chip on board (COB), a chip on film (COF), or the TCP type can be used. The COB has a structure for mounting the driver IC on a printed circuit board (PCB), and the COF has a structure for directly mounting the driver IC on a film constituting the FPC. Recently, the TCP, having a small size and a low price, has been used.  
         [0009]     The TCP has the following construction. First, a bump of the driver IC is bonded and attached to a pattern. The bump is formed of gold (Au). The pattern is formed of copper (Cu) and is disposed on an insulating film generally formed of polyimide. After that, resin is coated on the bump and the pattern to protect the combination of the bump and the pattern. A pattern protective layer (solder resist) is used to insulate the pattern. The pattern includes a power source, a signal input wire, and a ground wire.  
         [0010]     With such an arrangement, the driver IC packaged in the format of a TCP generates an address discharge at least eight times during 1/60 second corresponding to one TV field, in order to express 256 or more grayscales in the PDP. When the PDP is driven, high temperatures and electromagnetic interference (EMI) occurs.  
         [0011]     In order to dissipate heat from the driver IC, a heat dissipation sheet, which is formed of a solid material and serves as a heat sink, is attached to the TCP to dissipate heat generated by the driver IC into the atmosphere. However, this arrangement has a drawback in that a large amount of heat produced by the driver IC cannot be endured due to its inability to rapidly dissipate the produced heat. As a result, the driver IC is destroyed. What is needed is a more effective heat dissipation mechanism for such an IC driver located on a TCP.  
       SUMMARY OF THE INVENTION  
       [0012]     It is therefore an object of the present invention to provide an improved design for a plasma display device.  
         [0013]     It is further an object of the present invention to provide a design for a plasma display device where there is effective and efficient heat dissipation for a driver IC on a TCP.  
         [0014]     These and other objects can be achieved by a plasma display device having a lengthwise heat sink on a TCP cover plate that protects the TCP, thus efficiently dissipating heat from the driver IC.  
         [0015]     An exemplary plasma display device according to an embodiment of the present invention includes a plasma display panel, a printed circuit board assembly, a chassis base having one surface attached to the plasma display panel and another surface adapted to mount the printed circuit board assembly thereon, a TCP (tape carrier package) adapted to electrically connect the printed circuit board assembly to an electrode leading out from the plasma display panel, a driver IC (integrated circuit) arranged on the TCP, the driver IC being adapted to generate and selectively apply a pulse to the electrode leading out from the plasma display panel, a chassis bed arranged at an edge of the chassis base, the chassis bed being adapted to support one side of the driver IC on the TCP, a cover plate adapted to cover another side of the driver IC on the TCP, the cover plate being further adapted to be opposingly arranged at the chassis bed and a heat sink arranged at an outer surface of the cover plate and arranged lengthwise with the cover plate, the heat sink comprising vertical and horizontal air passages.  
         [0016]     The heat sink can be arranged lengthwise with the cover plate at an opposite outer surface thereof to the driver IC. The vertical and horizontal air passages and a plurality of the heat dissipating fins defining the vertical and the horizontal air passages can be arranged on an outer surface of the heat sink.  
         [0017]     Each of said plurality of heat dissipating fins can have a plate-shaped with a rectangular section.  
         [0018]     The vertical air passages can have a larger width than the horizontal air passages.  
         [0019]     A thickness of each heat dissipating fin can be smaller than a width of the horizontal air passages.  
         [0020]     The heat sink can be made of copper.  
         [0021]     The horizontal air passages can be produced by a process comprising extruding the heat dissipating fins.  
         [0022]     The vertical air passages can be produced by a process comprising cutting the heat dissipating fins at predetermined intervals.  
         [0023]     The plasma display device can further include a plurality of screws adapted to attach the heat sink to the outer surface of the cover plate.  
         [0024]     The heat sink can be perforated by a connection hole arranged at at least of each corner or a central edge of the heat sink.  
         [0025]     The plasma display panel can further include a thermal conduction sheet arranged between the heat sink and the outer surface of the cover plate, the thermal conduction sheet can be adapted to attach the heat sink to the cover plate.  
         [0026]     A support jaw can be outwardly protruded from an outer and upper surface of and lengthwise to the cover plate, the support jaw being integrally formed with the cover plate.  
         [0027]     The support jaw can have an ‘L’ shaped side section.  
         [0028]     The cover plate and the heat sink can be integrally formed with each other. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0029]     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:  
         [0030]      FIG. 1  is an exploded perspective view illustrating a plasma display device according to the first exemplary embodiment of the present invention;  
         [0031]      FIG. 2  is a sectional view illustrating an assembly state taken along line II-II of  FIG. 1 ;  
         [0032]      FIG. 3  is a perspective view illustrating a heat sink applied to a plasma display device according to the first exemplary embodiment of the present invention;  
         [0033]      FIG. 4  is a perspective view illustrating a heat sink applied to a plasma display device according to the second exemplary embodiment of the present invention;  
         [0034]      FIG. 5  is an exploded perspective view illustrating a plasma display device according to the second exemplary embodiment of the present invention using the heat sink of  FIG. 4 ;  
         [0035]      FIG. 6  is a sectional view illustrating an assembly state taken along line VI-VI of  FIG. 5 ;  
         [0036]      FIG. 7  is a partial plan view illustrating a heat sink applied to an exemplary embodiment of the present invention;  
         [0037]      FIGS. 8 and 9  illustrate a principle of heat dissipation of a heat sink according to each exemplary embodiment of the present invention using  FIG. 7 ;  
         [0038]      FIG. 10  is an exploded perspective view illustrating a plasma display device according to the third exemplary embodiment of the present invention;  
         [0039]      FIG. 11  is an exploded perspective view illustrating a plasma display device according to the fourth exemplary embodiment of the present invention; and  
         [0040]      FIG. 12  is an exploded perspective view illustrating a plasma display device according to the fifth exemplary embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0041]     Turning now to  FIGS. 1 through 3 ,  FIG. 1  is an exploded perspective view illustrating a plasma display device according to the first exemplary embodiment of the present invention,  FIG. 2  is a sectional view illustrating an assembly state taken along line II-II of  FIG. 1 , and  FIG. 3  is a perspective view illustrating a heat sink applied to the plasma display device according to the first exemplary embodiment of the present invention.  
         [0042]     The inventive plasma display device includes a plasma display panel (PDP) 1  and a chassis base  3 . The PDP  1  basically has two glass substrates formed as an exterior, and displays an image using a plasma discharge gas. The chassis base  3  dissipates heat from and supports the PDP  1 .  
         [0043]     A front cover (not shown) is disposed in front of the PDP 1 , and a rear cover (not shown) is disposed at the rear of the chassis base  3 . The front and rear covers are engaged with each other using a chassis screw (not shown).  
         [0044]     A heat dissipation sheet  5  can be disposed between the PDP  1  and the chassis base  3 . The heat dissipation sheet  5  dissipates the heat from the PDP  1  to the chassis base  3 . A filter (not shown) for shielding electromagnetic waves emitted from the PDP  1  is mounted at the front cover (not shown).  
         [0045]     Generally, the PDP  1  has a rectangular shape with a larger length in the X-axis direction than in the Y-axis direction of  FIG. 1 . The chassis base  3  has a rectangular shape corresponding to the PDP  1 , and can be formed of a material such as aluminum (Al) having good thermal conductivity.  
         [0046]     In other words, the PDP  1  is attached to and supported by one surface of the chassis base  3 , and a plurality of printed circuit board assemblies (PBAs)  7  for driving the PDP  1  are mounted on an opposite surface of the chassis base  3 . The PBAs  7  are substantially engaged to a boss  11  provided on a rear surface of the chassis base  3  using a setscrew  9 .  
         [0047]     The PBAs  7  mounted on the rear surface of the chassis base  3  includes an X board  7   a,  a Y board  7   b,  an image processing board  7   c,  a switching mode power supply board  7   d,  and an address buffer board  7   e.  The image processing board  7   c  receives an image signal from the exterior, generates a control signal for driving an address electrode  13  and a control signal for driving a display electrode (not shown) within the PDP  1 , and applies the control signals to each of the address buffer board  7   e,  the X board  7   a,  and the Y board  7   b.  The switching mode power supply board  7   d  wholly supplies power for driving the plasma display device.  
         [0048]      FIG. 2  exemplifies a structure for connecting a connector  21  of the address buffer board  7   e  to the address electrode  13  of the PDP  1  via TCP  15 . The TCP  15  for connecting the address buffer board  7   e  with the address electrode  13  includes a packaged driver IC  17 . The driver IC  17  selectively applies an address pulse to the address electrode  13  under the control of the address buffer board  7   e.    
         [0049]     The chassis base  3  can have a bent shape or can include a chassis bed  19  that provides mechanical rigidity for enduring torsion and bending. As shown in  FIG. 2 , the chassis bed  19  is disposed to avoid interference with the PBAs  7  that are disposed on the rear surface of the chassis base  3 . In  FIG. 2 , the chassis bed  19  is provided lengthwise (X-axis direction) of and on a rear lower surface of the chassis base  3 , such that it corresponds to the TCP  15  connected to the address buffer board  7   e  and the driver IC  17  packaged in the TCP  15 .  
         [0050]     A cover plate  23  is mounted at the chassis bed  19 , and the TCP  15  and the driver IC  17  are interposed between the chassis bed  19  and the cover plate  23 . The cover plate  23  is fixed to the chassis bed  19  using a setscrew  25 . The cover plate  23  is divided into two parts and covers the driver IC  17  to isolate the driver IC  17  from the exterior. The cover plate  23  dissipates heat that is generated when driving the driver IC  17  to the exterior. The cover plate  23  can also be configured at a lower end of the chassis base  3 , to correspond to each of the TCP  15  and the driver IC  17  situated lengthwise (X-axis direction) along the chassis base  3 . As shown in  FIG. 1 , the cover plate  23  can also be formed in a lengthwise (X-axis) direction along the chassis base  3  and serve to cover a plurality of individual driver ICs.  
         [0051]     Thermal grease  27  is interposed between the driver IC  17  and the chassis bed  19 , and a thermal conduction sheet  29  is interposed between the driver IC  17  and the cover plate  23 . Accordingly, the generated heat is dissipated to the chassis bed  19  and the cover plate  23  through the thermal grease  27  and through the thermal conduction sheet  29 .  
         [0052]     In the first exemplary embodiment of the present invention, the heat sink  30  of  FIG. 3  is used to effectively dissipate the heat passing through a two-part cover plate  23 . The heat sink  30  is integrally provided lengthwise along an outer surface of the two-part cover plate  23 . Accordingly, air passages AL 1  and AL 2  are respectively provided in vertical and horizontal directions. In other words, the heat sink  30  is mounted lengthwise along the two parts of the cover plate  23  and on an opposite outer surface of the cover plate  23  from the driver IC  17 . On heat sink  30  are a plurality of heat dissipating fins  31  that are designed to have a thickness and a width that provides the vertical and the horizontal air passages AL 1  and AL 2 .  
         [0053]     A method of manufacturing the heat sink  30  is as follows. First, the heat sink  30  is extruded with the heat dissipating fins  31  having the horizontal air passages (AL 2 ) formed lengthwise along the heat sink  30 . After that, the vertical air passages (AL 1 ) are formed by cutting the heat dissipating fins  31  in a vertical direction at predetermined lengthwise intervals along the heat sink  30 . Through this method, the heat sink  30  can be simply manufactured.  
         [0054]     The heat sink  30  is engaged to the outer surface of the cover plate  23  using six screws  33 . In more detail, the heat sink is perforated by connection holes  35  for the screws  33  the connection holes consuming space in place of heat dissipating fins at the four corners and at both edges at the center of the heat sink  30 .  
         [0055]     The heat sink  30  is formed of a material having good thermal conductivity such as copper (Cu). In order to quickly dissipate the heat from the driver IC  17 , the heat sink  30  is preferably made out of a material having a higher thermal conductivity than that of the cover plate  23  and the chassis bed  19 .  
         [0056]     The cover plate includes a support jaw  37  that integrally formed at an outer and upper surface along the length of the cover plate  23 . The support jaw  37  protrudes outward from the cover plate  23 . It is desirable that the support jaw  37  has an ‘L’-shaped side section.  
         [0057]     The support jaw  37  serves as an assembly reference surface for the heat sink  30  when the heat sink  30  is attached to the cover plate  23 . In more detail, the support jaw  37  supports an upper end of the heat sink  30  when the heat sink  30  is assembled to the coverplate  23 . The support jaw  37  can also broaden a contact area between the cover plate  23  and the heat sink  30 , resulting in improved heat dissipation efficiency.  
         [0058]     Turning now to  FIGS. 4 through 6 ,  FIG. 4  is a perspective view illustrating a heat sink  230  applied to a plasma display device according to the second exemplary embodiment of the present invention,  FIG. 5  is an exploded perspective view illustrating the plasma display device according to the second exemplary embodiment of the present invention using the heat sink  230  of  FIG. 4 , and  FIG. 6  is a sectional view illustrating an assembly state taken along line VI-VI of  FIG. 5 . Referring to  FIGS. 4 through 6 , construction of the heat sink  230  applied to the second exemplary embodiment of the present invention will now be described.  
         [0059]     As shown in  FIG. 4 , the heat sink  230  has the same shape as the heat sink  30  applied to the first exemplary embodiment, except that there is no connection holes present in the heat sink  230  according to the second embodiment of the present invention. In place of the connection holes are additional heat dissipating fins  31 . Because there are no connection holes in heat sink  230  of  FIGS. 4 through 6 , a thermal conduction sheet  39  is used instead of screws to attach the heat sink  230  to the cover plate  23  in the second embodiment of the present invention.  
         [0060]     Referring now to  FIGS. 5 and 6 , the heat sink  230  is integrally formed in a lengthwise direction over both parts of the two-part cover plate  23 , and is attached to both parts of the two-part cover plate  23 . Thermal conduction sheet  39  is interposed between a rear surface of the heat sink  230  and outer surfaces of the two-part cover plate  23 . The thermal conduction sheet  39  maintains an adhesive force binding the heat sink  230  to the outer surface of the two-part cover plate  23 . Except as described above, the heat sink  230  and the cover plate  23  of the second embodiment have the same basic constructions as that in the first exemplary embodiment.  
         [0061]     Turning now to  FIGS. 7 through 9 ,  FIG. 7  is a partial detailed plan view illustrating a portion of a heat sink applied to the exemplary embodiments of the present invention, and  FIGS. 8 and 9  illustrate a principle of heat dissipation of the heat sink according to the exemplary embodiments of the present invention together with  FIG. 7 . Referring to FIGS.  7  to  9 , a detailed construction and principle of heat dissipation of the heat sink  30  applied to the first exemplary embodiment of the present invention will be described. It is to be appreciated that essentially the same principles apply to heat sinks of other embodiments of the present invention, including heat sink  230  of  FIG. 4 .  
         [0062]     First, the heat dissipating fins  31  of the heat sink  30  are plate-shaped to have rectangular sections. Eight heat dissipating fins  31  are arranged and spaced apart from one another in the vertical (Y-axis) direction and extend in the lengthwise (X-axis) direction of the cover plate  23 . Accordingly, the horizontal air passages AL 2  are formed between individual heat dissipating fins  31 .  
         [0063]     When the eight heat dissipating fins  31  are defined as one set  32 , a plurality of heat dissipating fin sets  32  are arranged and spaced apart from one another along a lengthwise X-direction of the cover plate  23 . Accordingly, the vertical air passages AL 1  are formed between the heat dissipating fin sets  32 .  
         [0064]     At this time, an interval AL 2  between individual heat dissipating fins  31  and an interval AL 1  between the heat dissipating fin sets  32  are determined based on a thickness (t) and a width (T) of the heat dissipating fins  31  respectively. The vertical air passages AL 1  have a larger width than the horizontal air passages AL 2  (i.e., W AL1 &gt;W AL2 ). It is desirable that the thickness (t) of the heat dissipating fins  31  be less than the width (W AL2 ) of the horizontal air passage AL 2  (i.e., t&lt;W AL2 ).  
         [0065]     As shown in  FIG. 8 , the above-constructed heat sink  30  generally performs a function of heat dissipation using air convection through the vertical air passages AL 1 . The horizontal air passages AL 2  also allow airflow toward the vertical air passage (AL 1 ) because the pressure P AL1  in vertical passages AL 1  is less than the pressure P AL2  in the horizontal passages AL 2  (i.e., P AL1 &lt;P AL2 ).  
         [0066]     The inventive plasma display device can also have a pivot function where the screen of the plasma display device rotates by 90°. When the screen is rotated and erected at 90°, the heat sink  30  is oriented as in  FIG. 9 . In  FIG. 9 , with the display rotated, the vertical air passage AL 1  and the horizontal air passage AL 2  are exchanged in position.  
         [0067]     Accordingly, the function of heat dissipation resulting from air convection is achieved in the horizontal air passage AL 2  before the rotation of the plasma display device, and the airflow resulting from the pressure difference (P AL1 &gt;P AL2 ) is formed in the vertical air passage AL 1  before the rotation of the plasma display device, thus providing the same effect of heat dissipation.  
         [0068]     Turning now to  FIGS. 10 and 11 ,  FIG. 10  is an exploded perspective view illustrating a plasma display device according to the third exemplary embodiment of the present invention, and  FIG. 11  is an exploded perspective view illustrating a plasma display device according to the fourth exemplary embodiment of the present invention. Referring to  FIGS. 10 and 11 , the heat sinks  30  and  230  respectively applied to the first and second exemplary embodiments are now sectioned into to parts to correspond to the two-part cover plates  23 . The sectioned parts of the heat sink  330  of  FIG. 10  are assembled to cover plates  23  using screws  333 , and the sectioned parts of the heat sink  430  of  FIG. 11  are attached to the cover plates  23  through thermal conduction sheets  439 . The embodiments of  FIGS. 10 and 11  seek to overcome the drawback of the heat sinks  30  and  230  whose length is increased causing their carriage and attachment assembly to be difficult. In order to overcome this difficulty, the heat sinks  330  and  430  can each be sectioned with each section being assembled to an appropriate part of the respective two-part cover plates  23 .  
         [0069]     Turning now to  FIG. 12 ,  FIG. 12  is an exploded perspective view illustrating a plasma display device according to the fifth exemplary embodiment of the present invention. Referring to  FIG. 12 , heat dissipating fins  531  are integrally formed on an outer surface of a cover plate  523  according to the present exemplary embodiment. In other words, the cover plate  523  and a heat sink are not separately assembled or attached, but are integrally formed. Through the above construction, manufacturing costs can be reduced and an assembly process can be more simplified.  
         [0070]     As described above, in the inventive plasma display device, the heat sink is assembled or attached in a lengthwise direction on the cover plate, or is formed integrally with the cover plate so that heat generated by the driver IC can be effectively dissipated using the vertical and horizontal air passages in the heat sink. Further, there is an effect that even when the present invention is applied to a plasma display device having a pivot function, and the plasma display device is rotated and erected at 90°, the same effect of heat dissipation can be obtained.  
         [0071]     Furthermore, when the inventive heat sink is manufactured, the heat dissipating fins are extruded lengthwise of the heat sink and then the extruded heat dissipating fins are cut in the direction perpendicular to the length of the heat sink at predetermined intervals. Accordingly, the heat sink can be integrally formed. As a result, the manufacturing costs can be reduced and the assembly process thereof can be simplified. Furthermore, in one embodiment, the cover plate and the heat sink can be integrally formed, thus further simplifying the assembly process.  
         [0072]     While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.