Abstract:
Breakage of an IC included in a plasma display device can be prevented by a plasma display device including: a Plasma Display Panel (PDP); a chassis base attached the PDP on one side thereof and attached to a printed circuit board assembly on another side thereof; an Integrated Circuit (IC) package including an IC coupled between an electrode from the PDP and the printed circuit board assembly; and a cover plate attached to a chassis base interposing the IC package; and at least one of the chassis base and the cover plate includes at least one slit arranged in a vicinity of a portion corresponding to the 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 DEVICE earlier filed in the Korean Intellectual Property Office on 11 Oct. 2004 and there duly assigned Ser. No. 10-2004-0080873.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a plasma display device. More particularly, the present invention relates to a plasma display device that prevents breakage of an Integrated Circuit (IC) provided in a Tape Carrier Package (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 a plasma generated by a gas discharge.  
         [0006]     The plasma display device includes the PDP, a chassis base supporting the PDP, and a plurality of Printed circuit Board Assemblies (PBAs) attached to the chassis base on a side opposite to the PDP. The PBAs are connected to display electrodes or address electrodes, e.g., through a Flexible Printed Circuit (FPC) and a connector.  
         [0007]     Since the PDP includes two glass substrates attached to each other at their surfaces and discharge spaces formed therebetween, such a PDP has poor mechanical strength against an impact. The PDP produces substantial heat during operation, and accordingly, a thermal conduction sheet is provided at its rear side. The thermal conduction sheet conducts the heat produced by the PDP to spread it in planar directions.  
         [0008]     The chassis base is formed of a metallic material having sufficient mechanical strength to support the PDP, and is attached to the PDP through a double-sided adhesive tape. In addition to reinforcing the strength of the PDP, the chassis base supports the PBAs, dissipates the heat of the PDP, and prevents ElectroMagnetic Interference (EMI).  
         [0009]     The PDP supported by the chassis base addresses discharge cells and discharges the addressed discharge cells to realize a desired image, through address electrodes and display electrodes provided therein. The electrodes provided in the PDP are drawn out through the FPC, and the FPC is connected to the PBA.  
         [0010]     Therefore, the PDP is controlled by control signals of the PBA.  
         [0011]     On the other hand, the address electrodes are connected to a PBA through an FPC and a TCP, in order to receive an address voltage pulse. Such a TCP is provided with a driver IC. In order to express grayscales in the PDP, the driver IC repeatedly supplies an address voltage pulse to the address electrodes at a high frequency. Therefore, the driver IC produces a substantial amount of heat and EMI.  
         [0012]     The driver IC is therefore provided with a heat dissipation mechanism disposed in a marginal region of the chassis base. That is, the driver IC provided by the TCP is disposed in the marginal region of the chassis base and supplied with a thermal grease. In addition, a cover plate is provided to the driver IC and supplied with a thermal conduction sheet. The cover plate is fixed to the chassis base by setscrews, and thus the TCP and driver ICs provided thereat are mounted on the chassis base.  
         [0013]     When the number of driver ICs mounted on one TCP is decreased, the driver IC mounted at one TCP can be lengthened. A long driver IC can easily suffer breakage when closely assembled between the chassis base and the cover plate.  
         [0014]     In addition, the PDP and the chassis base have respective thermal expansion coefficients. A difference of the thermal expansion coefficients can cause the assembly of the PDP and the chassis base to bend. The PDP is typically formed with a ratio of width (i.e., horizontal length) to height (i.e., vertical length) of about 16:9, and the bending of the assembly can be more severe in the horizontal direction than in the vertical direction. Due to the bending of the assembly, driver ICs disposed on both horizontal ends of the chassis base can suffer breakage more easily.  
       SUMMARY OF THE INVENTION  
       [0015]     The present invention has been made in an effort to provide a plasma display device having advantages of preventing breakage of an Integrated Circuit (IC) provided by a Tape Carrier Package (TCP).  
         [0016]     An exemplary plasma display device according to an embodiment of the present invention includes: a Plasma Display Panel (PDP); a chassis base attached the PDP on one side thereof and attached to a printed circuit board assembly on another side thereof; an IC package including an IC coupled between an electrode from the PDP and the printed circuit board assembly; and a cover plate attached to a chassis base interposing the IC package; and at least one of the chassis base and the cover plate includes at least one slit arranged in a vicinity of a portion corresponding to the IC.  
         [0017]     The chassis base preferably includes a reinforcing member arranged at a long edge along a long edge direction thereof.  
         [0018]     The cover plate is preferably elongated along the long edge direction of the chassis base to cover a plurality of IC packages.  
         [0019]     The IC is preferably rectangular in shape having a long edge and a short edge; the chassis base is preferably rectangular in shape having a long edge and a short edge; and the long edge of the IC is preferably arranged in parallel with the short edge of the chassis base.  
         [0020]     The at least one slit is preferably arranged in parallel with a long edge of the driver IC and is preferably elongated from a central portion to an edge of the cover plate.  
         [0021]     The at least one slit preferably includes a pair of slits respectively arranged on opposite sides of long edges of the IC.  
         [0022]     The IC is preferably rectangular in shape having a long edge and a short edge; the chassis base is preferably rectangular in shape having a long edge and a short edge; and the long edge of the IC is preferably arranged in parallel with the long edge of the chassis base.  
         [0023]     The at least one slit is preferably arranged in the cover plate and preferably has a horseshoe shape corresponding to a short edge and a pair of long edges of the IC.  
         [0024]     The at least one slit is preferably arranged in parallel with a long edge of the IC and is preferably elongated from a central portion to an edge of the reinforcing member.  
         [0025]     The at least one slit preferably includes a pair of slits respectively arranged on opposite sides of long edges of the IC.  
         [0026]     The at least one slit is preferably arranged in the reinforcing member and preferably has a horseshoe shape corresponding to a short edge and a pair of long edges of the IC.  
         [0027]     A plurality of ICs preferably correspond to each portion demarcated by the at least one slit.  
         [0028]     At least one end of a portion demarcated by the at least one slit is preferably an open end.  
         [0029]     The open end is preferably bent to protrude from a plane of the cover plate or the reinforcing member.  
         [0030]     The IC package preferably includes a tape carrier package combined with the IC.  
         [0031]     Such a slit or slits form the incision portion in the cover plate or the reinforcing member, and accordingly, the incision portion can become offset when forced by the IC between the reinforcing member and the cover plate.  
         [0032]     That is, the pressure applied to the IC becomes constant due to the incision portion.  
         [0033]     Therefore, breakage of the IC by an external force can be prevented.  
         [0034]     In addition, breakage of the IC caused by bending of the chassis base due to the difference between thermal expansion coefficients of the PDP and the chassis base can be prevented. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0035]     A more complete appreciation of the present invention, and many of the attendant advantages thereof, will be readily apparent as the present invention 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:  
         [0036]      FIG. 1  is a perspective view of a plasma display device according to a first embodiment of the present invention.  
         [0037]      FIG. 2  is a sectional view along the line A-A of  FIG. 1 .  
         [0038]      FIG. 3  is an exploded perspective view of  FIG. 2  including a chassis base, a reinforcing member, a TCP, and a cover plate.  
         [0039]      FIG. 4  is an exploded perspective view of a chassis base, a reinforcing member, a TCP, and a cover plate according to a second embodiment of the present invention.  
         [0040]      FIG. 5  is a sectional view along the line A-A of  FIG. 1  according to a third embodiment of the present invention.  
         [0041]      FIG. 6  is an exploded perspective view of  FIG. 5  including a chassis base, a reinforcing member, a TCP, and a cover plate.  
         [0042]      FIG. 7  is an exploded perspective view of a chassis base, a reinforcing member, a TCP, and a cover plate according to a fourth embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0043]     Embodiments of the present invention are described in detail below with reference to the accompanying drawings.  
         [0044]      FIG. 1  is a perspective view of a plasma display device according to a first embodiment of the present invention,  FIG. 2  is a sectional view along the line A-A of  FIG. 1 , and  FIG. 3  is an exploded perspective view of  FIG. 2  including a chassis base, a reinforcing member, a TCP, and a cover plate.  
         [0045]     The plasma display device includes a PDP  11  for displaying an image using a gas discharge, heat dissipation sheets  13 , PBAs  15   a  to  15   e  (hereinafter, the PBAs  15   a  to  15   e  can collectively or respectively be referred to by reference numeral  15 ) electrically connected to the PDP  11  so as to drive it, and a chassis base  17  mounted with and supporting the PDP  11  at its front side through a double-sided adhesive tape  16  and mounted with and supporting the PBAs  15  at its rear side.  
         [0046]     The heat dissipation sheet  13  is attached to the rear of the PDP  11  so as to conduct and spread heat generated by the gas discharge of the PDP  11  in planar directions (i.e., directions on the x-y plane shown in  FIG. 1 ). The heat dissipation sheet  13  can be made of a heat dissipation material having sufficient thermal conductivity such as acryl, graphite, metal, or carbon nano-tubes.  
         [0047]     The PBA  15  can be attached to a boss  18  of the chassis base  17  by a setscrew  19  (refer to  FIG. 2 ). An image processing/controlling board  15   a  among the PBAs  15  receives an external video signal, generates control signals for driving address electrodes  21  and display electrodes (not shown), and respectively supplies them to an address driving board  15   b , a scan driving board  15   c , and a sustain driving board  15   d . A power supply board  15   e  supplies electric power required for driving the plasma display device.  
         [0048]     For driving the PDP  11 , the address driving board  15   b , the scan driving board  15   c , and the sustain driving board  15   d  are connected to corresponding electrodes of the PDP  11  via respective FPCs  23 . For a representative example, the connection between the address driving board  15   b  and the PDP  11  via the FPC  23  is illustrated in the drawings and hereinafter described. Although not shown in the drawings in detail, the scan driving board  15   c  and the sustain driving board  15   d  are also respectively connected to scan electrodes (not shown) and sustain electrodes (not shown) of the PDP  11  via an FPC (not shown).  
         [0049]     A driver IC  125  is coupled between the address driving board  15   b  and the address electrodes  21  of the PDP  11 . The driver IC  125  selectively supplies an address voltage pulse to the address electrodes  21  of the PDP  11  by a control signal of the address driving board  15   b . Discharge cells of the PDP  11  are then selected by a scan voltage pulse supplied to the scan electrodes and an address voltage pulse supplied to the address electrodes  21 . Such a driver IC  125  for supplying the address voltage pulse can be realized by a driver IC package. For example, the driver IC  125  can be packaged into the FPC  23  to form a TCP  27 . The TCP  27  is connected to the address driving board  15   b  at its input side, and is connected to the address electrode  21  of the PDP  11  via the FPC  23  at its output side.  
         [0050]     The address electrodes  21  of the PDP  11  are drawn out externally via the FPC  23 , and connected to the address driving board  15   b  via the TCP  27  and driver IC  125  disposed at an end of the chassis base  17 .  
         [0051]     The chassis base  17  can be formed by pressing a thin plate of a metallic material. The chassis base  17  must have sufficient mechanical strength to withstand twisting and bending forces. As shown in  FIG. 2 , the chassis base  17  can preferably be bent at its end to form an L-shaped cross-section, or can preferably be provided with a reinforcing member  29  (refer to  FIG. 1 ). More preferably, according to the present embodiment, a reinforcing member  29   a  is added to a bent end of the chassis base  17  as shown in  FIG. 2 .  
         [0052]     As shown in  FIG. 1 , the reinforcing member  29  can be formed at an appropriate position that does not cause any spatial interference with the PBAs  15  mounted on the rear side of the chassis base  17 . In addition, the reinforcing member  29   a  can be formed at a marginal area of the chassis base  17 . The reinforcing member  29   a  can support the driver IC  125  and the TCP  27 . The driver IC  125  and the TCP  27  interconnect the address electrodes  21  of the PDP  11  drawn out from the front side of the chassis base  17  and the address driving board  15   b  attached to the rear side of the chassis base  17 .  
         [0053]     The chassis base  17  has a rectangular shape having its long edge in the x-axis direction and its short edge in the y-axis direction. The driver IC  125  also has a rectangular shape having long and short edges. The reinforcing member  29   a  can be extended along a long edge direction (i.e., the x-axis direction in the drawings) near a long edge of the chassis base  17 .  
         [0054]     A cover plate  31  is attached to the chassis base  17  interposing the TCP  27  and the driver IC  125 . The cover plate  31  is fixed to the chassis base  17  (in more detail, to the reinforcing member  29   a ) by a setscrew  33 , so as to fix the driver IC  125  to the chassis base  17 . The cover plate  31  dissipates heat produced by the driver IC  125  during its operation. The cover plate  31  and the reinforcing member  29   a  are respectively provided with a penetration hole  33   a  and a threaded hole  33   b  for receiving the setscrew  33 . Although the cover plate  31  can be elongated in the long edge direction (i.e., the x-axis direction) to cover a plurality of the TCPs  27  and the driver ICs  125  as shown in  FIG. 1 , it can also be separately provided to each set of the TCP  27  and the driver IC  125  disposed along the long edge (i.e., in the x-axis direction) of the chassis base  17 . When the cover plate  31  is elongated along the long edge direction of the chassis base  17 , the cover plate  31  can be easily atached to the chassis base  17  and can form a uniform combining force throughout the plurality of driver ICs  125 .  
         [0055]     For such reasons, according to an embodiment of the present invention, a reinforcing member  29   a  is provided at a long edge side end of the chassis base  17 . The cover plate  31  is attached to the reinforcing member  29   a . The driver IC  125  is disposed between the cover plate  31  and the reinforcing member  29   a . A thermal grease  34  is applied between the driver IC  125  and the reinforcing member  29   a , and a thermal conduction sheet  35  is disposed between the driver IC  125  and the cover plate  31 . Therefore, when the driver IC  125  operates, heat caused thereby is conducted to the reinforcing member  29   a  and the cover plate  31  through the thermal grease  34  and the thermal conduction sheet  35  so as to be rapidly dissipated. When a plasma display device is not provided with such a reinforcing member  29   a , the thermal grease  34  can be applied between the driver IC  125  and the chassis base  17 .  
         [0056]     As shown in  FIG. 3 , the driver IC  125  can be elongated on a TCP  27  to reduce the number thereof. For example, a TCP having two driver ICs (not shown) each provided with 96 output terminals and a TCP having one driver IC having 192 (or 256 or 384) output terminals can be compared. A driver IC having a greater number of output terminals is longer than a driver IC having a smaller number of output terminals. Therefore, the driver IC  125  is formed in a rectangular shape having long and short edges as shown in  FIG. 3 . Such a non-square rectangular-shaped driver IC  125  between the cover plate  31  and the chassis base  17  (or the reinforcing member  29   a ) can easily suffer breakage when a bending force is applied due to the bending of the chassis base  17 .  
         [0057]     In order to prevent such breakage, the chassis base  17  or the cover plate  31  is provided with one or more slits  137  at a position facing the driver IC  125 . The slits  137  can be formed in one of or both the chassis base  17  and the cover plate  31 . When the chassis base  17  is provided with the reinforcing member  29   a , the slits  137  can be formed in one of or both the cover plate  31  and the reinforcing member  29   a . An embodiment of the present invention is described hereinafter in connection with an exemplary case in which the slits  137  are formed in the cover plate  31  and/or the reinforcing member  29   a.    
         [0058]     When an excessive force is applied to the cover plate  31  and the reinforcing member  29   a  and accordingly to the driver IC  125  disposed therebetween, incision portion  137   a  formed in the cover plate  31  and/or the reinforcing member  29   a  by the slits  137  becomes slightly bent to be offset from the cover plate  31  and/or the reinforcing member  29   a  as shown in  FIG. 2  and  FIG. 3 . That is, at least one end of the incision portion  137   a  demarcated by the slits  137  is formed as an open end. The open end is bent to protrude from a plane of the cover plate  31  or the reinforcing member  29   a . Therefore, the incision portion  137   a  can prevent excessive external force from being applied to the driver IC  125 , thereby preventing breakage of the driver IC  125 .  
         [0059]     In addition, even if a bending force is applied to the assembly of the PDP  11  and chassis base  17  due to a difference in thermal expansion coefficients of the PDP  11  and the chassis base  17 , the slits  137  can absorb the difference in the thermal expansions. Furthermore, the slits  137  can prevent the bending force from being applied to the driver IC  125  because the incision portion  137   a  becomes offset from the plane of the cover plate  31  or the reinforcing member  29   a . Therefore, it is difficult for the driver IC  125  having the long edge to suffer breakage. Such an effect will not be described in detail.  
         [0060]      FIG. 2  and  FIG. 3  illustrate a scheme according to a first embodiment of the present invention. As shown in the drawings, the driver IC  125  is provided on the TCP  27  with its long edge in parallel with a short edge of the chassis base  17 . In order to protect such a driver IC  125 , the slits  137  are formed in the cover plate  31 , in parallel with the long edge of the driver IC  125  (i.e., along the y-axis direction in the drawings). The slits  137  are elongated from a central portion of the cover plate  31  to an edge thereof. The slits  137  can be formed at only one side of long edges of the driver IC  125 . However, it is preferable that they are formed in pairs at opposite sides of the driver IC  125 , such that the slits  137  can be respectively disposed on opposite sides of the long edges of the driver IC  125 . The slits  137  form the incision portion  137   a  in the cover plate  31 . As shown by the one-point chain lines in  FIG. 2 , the incision portion  137   a  can be bent to become slightly offset from the cover plate  31  by a biasing force of the driver IC  125 , and therefore breakage of the driver IC  125  can be prevented due to a strong external force received from the cover plate  31  and due to a bending force caused by the difference in thermal expansion coefficients.  
         [0061]      FIG. 4  relates to a second embodiment of the present invention, which has similar structural features, operation, and effect as the first embodiment, and hereinafter, the following description is focused only on features of the second embodiment that are different from the first embodiment.  
         [0062]     The driver IC  225  is provided on the TCP  27  having its long edge in parallel with the long edge of the chassis base  17 . In order to protect such a driver IC  225 , slits  237  form an incision portion  237   a  in the cover plate  31 , in a horseshoe shape corresponding to a short edge and a pair of long edges of the driver IC  225 . Such slits  237  can be altered in shape to an L shape, when a side corresponding to the short edge of the driver IC is formed to reach an end of the cover plate  31 . Considering that a larger bending force is applied to the long edge of the chassis base  17  (i.e., in the x-axis direction) than the short edge thereof (i.e., in the y-axis direction), such an arrangement of the driver IC  225  can increase the possibility of breakage of the driver IC  225 . Therefore, the slits  237  and the incision portion  237   a  formed in such a position can more effectively prevent the breakage of the driver IC  225 .  
         [0063]      FIG. 5  and  FIG. 6  relate to a third embodiment of the present invention, which has similar structural features, operation, and effect as the first embodiment, and hereinafter, the following description is focused only on features of the third embodiment different from the first embodiment.  
         [0064]     The driver IC  325  is provided on the TCP  27  having its long edge in parallel with the short edge of the chassis base  17 . In order to protect such a driver IC  325 , slits  337  are formed in the reinforcing member  29   a , in parallel with the long edge of the driver IC  325 . The slits  337  are elongated from a central portion of the reinforcing member  29   a  to an edge thereof. The slits  337  can be formed on only one side of long edges of the driver IC  325 . However, it is preferable that they are formed in pairs at opposite sides of the driver IC  325 , such that each slit  337  can correspond to each long edge of the driver IC  125 . An incision portion  337   a  is formed in the reinforcing member  29   a  by the slits  337 . As shown by one-point chain lines in  FIG. 5  and  FIG. 6 , the incision portion  337   a  can be bent to become slightly offset from the reinforcing member  29   a  by a biasing force of the driver IC  325 , and therefore, the breakage of the driver IC  325  can be prevented due to a strong external force received from the reinforcing member  29   a  and due to a bending force caused by the difference in thermal expansion coefficients. Such slits  337  formed in the reinforcing member  29   a  can enable the incision portion  337   a  to become inwardly offset with respect to the chassis base  17 , and accordingly can prevent interference with components mounted on the rear of the cover plate  31 .  
         [0065]      FIG. 7  relates to a fourth embodiment of the present invention, which has similar structural features, operation, and effect as the third embodiment, and hereinafter, the following description is focused on only features of the second embodiment that are different from the third embodiment.  
         [0066]     The driver IC  425  is provided on the TCP  27  having its long edge in parallel with the long edge of the chassis base  17 . In order to protect such a driver IC  425 , slits  437  are formed in the reinforcing member  29   a  and form an incision portion  437   a , in a horseshoe shape corresponding to one long edge and a pair of short edges of the driver IC  425 . Such slits  437  can be altered in shape to an L shape, when a side corresponding to the long edge of the driver IC is formed to reach an end of the reinforcing member  29   a.    
         [0067]     As described above, according to a plasma display device of an embodiment of the present invention, a reinforcing member is provided at a long edge of a chassis base, and a cover plate is attached to the reinforcing member interposing a TCP provided with a driver IC. In addition, slits are formed in the reinforcing member or the cover plate in the vicinity of the driver IC such that an incision portion formed by the slits can become offset from the reinforcing member or the cover plate when the driver IC is forced by the cover plate. Therefore, breakage of the driver IC between the reinforcing member and the cover plate can be prevented. Furthermore, breakage of the driver IC can also be prevented due to the difference between thermal expansion coefficients of the PDP and the chassis base.  
         [0068]     While the present invention has been described in connection with exemplary embodiments, it is to be understood that the present invention is not limited to these embodiments, but, on the contrary, the present invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.