Abstract:
A heat dissipation structure for a display panel efficiently dissipates heat generated during operation of the display panel, and a display module including the heat dissipation structure is also so characterized. The heat dissipation structure is capable of preventing electromagnetic waves generated during the operation of the display panel operation from adversely influencing a driving circuit. The heat dissipation structure comprises: a display panel; a heat dissipating sheet contacting a rear surface of the display panel; and a chassis base disposed on a rear side of the heat dissipating sheet and connected to the display panel via a double-sided adhesive element. The heat dissipating sheet includes two heat dissipating layers and a metal sheet layer interposed between the two heat dissipating layers.

Description:
CLAIM OF PRIORITY 
   This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. § 119 from an application entitled STRUCTURE FOR HEAT DISSIPATION OF DISPLAY PANEL, AND DISPLAY MODULE EQUIPPED WITH THE SAME, earlier filed in the Korean Intellectual Property Office on Nov. 10, 2004 and there duly assigned Serial No. 10-2004-0091527. 
   BACKGROUND OF THE INVENTION 
   1. Technical Field 
   The present invention relates to a heat dissipation structure for a display panel and a display module equipped with the structure. More particularly, the invention relates to a heat dissipation structure for a display panel which can efficiently discharge heat generated during the operation of the display panel, and which can prevent malfunction of a driving circuit due to electromagnetic waves generated during the operation of the display panel, and a display module equipped with the structure. 
   2. Related Art 
   A display module used in a plasma display device comprises a display panel, a plurality of driving circuit boards including circuits for driving the display panel, and a chassis which supports the driving circuit boards. 
   The display panel is formed by coupling a front board and a rear board, and is electrically connected to the driving circuit boards by connection cables. 
   Since the front side of the chassis is supported by the display panel and the rear side of the chassis is supported by the driving circuit boards, a reinforcement member is additionally mounted to the chassis to supplement the strength of the chassis. A chassis base acts as a ground for a circuit connected to the display panel and the driving circuit boards, and cools the display panel by discharging heat generated during the operation of the display panel. The chassis base also supports the display panel and the driving circuit boards. 
   The display panel and the chassis base maybe adhered to each other by a double-sided adhesive element. A heat dissipating sheet may be disposed between the display panel and the chassis base to dissipate the heat generated during the operation of the display panel. 
   A heat dissipating sheet is disposed between the display panel and the chassis base so that the heat generated during the operation of the display panel is smoothly transmitted and dissipated through the heat dissipating sheet. However, an air layer is formed between the heat dissipating sheet and the chassis base, and thus, only a portion of the heat dissipating sheet contacts the chassis base. The air layer interferes with the dissipation of the heat generated during the operation of the display panel through the chassis base, and thus, there is a need for a heat dissipation structure to effectively cool the display panel. 
   SUMMARY OF THE INVENTION 
   The present invention provides a heat dissipation structure for a display panel which can efficiently dissipate heat generated during the operation of the display panel, and a display module including the heat dissipation structure. 
   The present invention also provides a heat dissipation structure for a display panel which can prevent electromagnetic waves generated during the operation of the display panel from affecting a driving circuit. 
   According to an aspect of the present invention, there is provided a heat dissipation structure of a display panel, comprising: a display panel; a heat dissipating sheet contacting a rear surface of the display panel; and a chassis base disposed on a rear side of the heat dissipating sheet and connected to the display panel via a double-sided adhesive element; wherein the heat dissipating sheet includes two heat dissipating layers and a metal sheet layer interposed between the two heat dissipating layers. 
   Preferably, both of the heat dissipating layers are made of graphite, one of the two heat dissipating layers contacts the display panel and is made of graphite, and the other heat dissipating layer contacts the chassis base and is made of a material from a silicon group or acryl group. 
   The heat dissipating sheet may not extend to the edges of the rear surface of the display panel, the double-sided adhesive element may be disposed a predetermined distance from the heat dissipating sheet, and an Electro Magnetic Interference (EMI) sponge may be disposed in the space between the heat dissipating sheet and the double-sided adhesive element. 
   Preferably, the metal sheet layer includes a bent end portion extending to and contacting the display panel, and the EMI sponge is disposed in the space between the bent end portion and the chassis base, or the metal sheet layer includes a bent end portion extending to and contacting the chassis base, and the EMI sponge is disposed in the space between the bent end portion and the display panel. Alternatively, the end of the metal sheet layer extends further than the two heat dissipating layers, and the EMI sponge is disposed on the front and rear surfaces of the metal sheet layer. 
   The heat dissipation sheet may not extend to the edges of the rear surface of the display panel, the double-sided adhesive element may be disposed a predetermined distance from the heat dissipating sheet, and the EMI sponge may be disposed on a side of the double-sided adhesive element opposite to the heat dissipating sheet between the chassis base and the display panel. 
   The display panel may be a plasma display panel. 
   According to another aspect of the present invention, there is provided a display module comprising: a display panel; a driving circuit board driving the display panel; a chassis base supporting the display panel and the driving circuit board; and a heat dissipating sheet having a surface contacting a rear surface of the display panel; wherein the chassis base is connected to the display panel via a double-sided adhesive element, the heat dissipating sheet includes two heat dissipating layers, and a metal sheet layer is interposed between the two heat dissipating layers. 
   Preferably, both of the heat dissipating layers are made of graphite, one of the two heat dissipating layers contacts the display panel and is made of graphite, and the other heat dissipating layer contacts the chassis base and is made of a material from a silicon group or acryl group. 
   The heat dissipating sheet may not extend to the edges of the rear surface of the display panel, the double-sided adhesive element may be disposed a predetermined distance from the heat dissipating sheet, and an EMI sponge may be disposed in the space between the heat dissipating sheet and the double-sided adhesive element. 
   Preferably, the metal sheet layer includes a bent end portion extending to and contacting the display panel, and the EMI sponge is disposed in the space between the bent end portion and the chassis base, or the metal sheet layer includes a bent end portion extending to and contacting the chassis base, and the EMI sponge is disposed in the space between the bent end portion and the display panel. Alternatively, the end of the metal sheet layer extends further than the two heat dissipating layers, and the EMI sponge is disposed on the front and rear surfaces of the metal sheet layer. 
   The heat dissipation sheet may not extend to the edges of the rear surface of the display panel, the double-sided adhesive element may be disposed a predetermined distance from the heat dissipating sheet, and the EMI sponge may be disposed on a side of the double-sided adhesive element opposite to the heat dissipating sheet between the chassis base and the display panel. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     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: 
       FIG. 1  is an exploded perspective view of a display module; 
       FIG. 2  is a cross-sectional view taken along line II-II of  FIG. 1 ; 
       FIG. 3  is a cross-sectional view of a heat dissipation structure of a display panel according to a first embodiment of the present invention; 
       FIG. 4  is a cross-sectional view of a heat dissipation structure of a display panel according to a second embodiment of the present invention; 
       FIG. 5  is a cross-sectional view of a heat dissipation structure of a display panel according to a third embodiment of the present invention; and 
       FIGS. 6  thru  8  are cross-sectional views of modifications of the heat dissipation structure of the display panel shown in  FIG. 5 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. Like reference numerals in the drawings denote like elements, and thus their description will not be repeated. 
     FIG. 1  is a perspective view of a display module used in a plasma display device, which is a flat display device. 
   Referring to  FIG. 1 , the display module used in a plasma display device includes a display panel  50 , a plurality of driving circuit boards  40  including circuits for driving the display panel  50 , and a chassis  10  that supports the driving circuit boards  40 . 
   The display panel  50  is formed by coupling a front board  51  and a rear board  52 , and is electrically connected to the driving circuit boards  40  by connection cables  20 . 
   Since the front side of the chassis  10  is supported by the display panel  50  and the rear side of the chassis  10  is supported by the driving circuit board  40 , a reinforcement member  12  is additionally mounted to the chassis  10  to supplement the strength of the chassis  10 . A chassis base  11  acts as a ground for a circuit connected to the display panel  50  and the driving circuit board  40 , and cools the display panel  50  by discharging heat generated during the operation of the display panel  50 . The chassis base  11  also supports the display panel  50  and the driving circuit boards  40 . 
   The display panel  50  and the chassis base  11  may be adhered to each other by a double-sided adhesive element  54 . A heat dissipating sheet  53  may be disposed between the display panel  50  and the chassis base  11  so as to dissipate heat generated during the operation of the display panel  50 . 
     FIG. 2  is a cross-sectional view taken along line II-II of  FIG. 1 . 
   Referring to  FIG. 2 , the heat dissipating sheet  53  is disposed between the display panel  50  and the chassis base  11  so that heat generated during the operation of the display panel  50  is smoothly transmitted and dissipated through the heat dissipating sheet  53 . However, an air layer  70  is formed between the heat dissipating sheet  53  and the chassis base  11 , and thus, less than 50 percent of the heat dissipating sheet  53  contacts the chassis base  11 . The air layer  70  interferes with the dissipation of the heat generated during the operation of the display panel  50  through the chassis base  11 , and thus, there is a need for a heat dissipation structure to effectively cool the display panel  50 . 
     FIG. 3  is a cross-sectional view of a heat dissipation structure of a display panel according to a first embodiment of the present invention. 
   Referring to  FIG. 3 , the heat dissipation structure of a display panel according to the first embodiment includes a display panel  50 , a heat dissipating sheet  153 , and a chassis base  11 . 
   The display panel  50  is not limited to a plasma display panel, which is described herein merely as an example, and any display panel which generates heat during its operation and which needs to dissipate the heat for cooling may be used. 
   The heat dissipating sheet  153  contacts a rear surface of the display panel  50  and transmits the heat generated during the operation of the display panel  50  to the chassis base  11  for dissipation. The heat dissipating sheet  153  includes two heat dissipating layers  153   a  and  153   c  which are made of graphite, which has a high thermal conductivity, and a metal sheet layer  153   b  interposed between the heat dissipating layers  153   a  and  153   c . The metal sheet layer  153   b  may be an aluminum layer or the like. 
   The heat dissipating layers  153   a  and  153   c  are, preferably, made of a material having high thermal conductivity, such as silicon, acryl, or urethane, instead of graphite, or are manufactured by mixing ultrafine ferrite particles or a conductive filler. 
   Alternatively, the two heat dissipating layers  153   a  and  153   c  may be made of different materials. In this case, the dissipating layer  153   a  which contacts the chassis base  11  may be made of a material included in the silicon or acryl group. A contact area between the layer made of a material included in the silicon or acryl group and the chassis base  11  is larger than a contact area between a graphite layer and the chassis base  11 , even when a large force is not applied, since the material included in the silicon or acryl group has better elastic properties. Therefore, heat generated during the operation of the display panel  50  can be smoothly transmitted to the chassis base  11 . 
   The chassis base  11  is a thin plate, and a reinforcement member  12  is installed on the rear side of the chassis base  11  to supplement the strength of the chassis base  11 . The display panel  50  is connected to the front side of the chassis base  11  by an adhesive element  54 , and the rear side of the chassis base  11  is connected to a driving circuit board  40 . 
   In the above structure, the thermal conduction of the heat dissipating sheet  153  is greater than that of a conventional heat dissipating sheet, and the heat generated during the operation of the display panel  50  is smoothly dissipated. Moreover, the metal sheet layer  153   b  not only improves the thermal conductivity of the heat dissipating sheet  153 , but also shields the driving circuit board  40  from electromagnetic waves generated during the operation of the display panel  50  or the driving circuit board  40  during the operation of the display panel  50 . 
     FIG. 4  is a cross-sectional view of a heat dissipation structure of a display panel  50  according to a second embodiment of the present invention. 
   Referring to  FIG. 4 , the heat dissipation structure according to the present embodiment includes the display panel  50 , a heat dissipating sheet  153 , a chassis base  11 , and an Electro Magnetic Interference sponge or EMI sponge  155 . 
   The display panel  50  and the heat dissipating sheet  153  of  FIG. 4  are the same as the display panel  50  and the heat dissipating sheet  153  of  FIG. 3 . 
   In the present embodiment, the chassis base  11  is composed of a conductive material. 
   The EMI sponge  155  is formed by adhering a conductive fabric, a conductive film or a metal foil to the outside of an elastic sponge, and it is disposed in a region where the heat dissipating sheet  153  is not disposed between the display panel  50  and the chassis base  11 . That is, the EMI sponge  155  is disposed on the opposite side of a double-sided adhesive element  54  from the heat dissipating sheet  153 . The EMI sponge  155  contacts the display panel  50  and the chassis base  11 . 
   In the heat dissipation structure according to the second embodiment, the heat dissipating sheet  153  has a multi-layer structure, thus improving thermal conductivity, and at the same time, the display panel  50  and the chassis base  11  are electrically connected to each other. Therefore, the influence of electromagnetic waves on the driving circuit board  40  installed on the rear side of the chassis base  11 , and on circuit elements disposed on the driving circuit board  40 , is significantly reduced. 
     FIG. 5  is a cross-sectional view of a heat dissipation structure of a display panel  50  according to a third embodiment of the present invention. 
   Referring to  FIG. 5 , the heat dissipation structure includes the display panel  50 , a heat dissipating sheet  153 , a chassis base  11 , and an EMI sponge  155 . 
   The display panel  50  and the heat dissipating sheet  153  of  FIG. 5  are the same as the display panel  50  and the heat dissipating sheet  153  of  FIGS. 3 and 4 . 
   The chassis base  11  according to the present embodiment is composed of a conductive material. 
   The EMI sponge  155  is formed by adhering a conductive fabric, a conductive film or a metal foil to the outside of an elastic sponge as in  FIG. 4 , but the EMI sponge  155  contacts a metal sheet layer  153   b  included in the heat dissipating sheet  153  between the display panel  50  and the chassis base  11 . That is, the EMI sponge  155  is disposed on the same side of the double-side adhesive element  54  as the heat dissipating sheet  153 . The EMI sponge  155  contacts the display panel  50 , the chassis base  11 , and the metal sheet layer  153   b . The size of the metal sheet layer  153   b  may be different from the sizes of the other layers  153   a  and  153   c  included in the heat dissipating sheet  153 . In this case, a gap between the other layers  153   a  and  153   c  of the heat dissipating sheet  153  is filled with the EMI sponge  155  so that the EMI sponge  155  can contact the metal sheet layer  153   b  as shown in  FIG. 5 . 
   In the heat dissipation structure according to the third embodiment, the heat dissipating sheet  153  has a multi-layer structure and can improve thermal conductivity. Furthermore, the display panel  50  and the metal sheet layer  153   b  are electrically grounded to the chassis base  11 , and thus, electromagnetic waves generated during the operation of the display panel  50  can be captured by the metal sheet layer  153   b  and discharged through the chassis base  11 . Consequently, the influence of electromagnetic waves on the driving circuit board  40  installed on the rear side of the chassis base  11 , and on circuit elements disposed on the driving circuit board  40 , is remarkably reduced, and the electromagnetic waves radiating from the front of a display device are shielded while a user is watching video through the display device. 
     FIGS. 6  thru  8  are cross-sectional views of modifications of the heat dissipation structure of the display panel  50  shown in  FIG. 5 . 
   Referring to  FIG. 6 , the metal sheet layer  153   b  may have a bent portion at its end bent toward the chassis base  11 . The bent portion of the metal sheet layer  153   b  contacts the chassis base  11 . Furthermore, a space between the bent portion of the metal sheet layer  153   b  and the display panel  50  is filled with the EMI sponge  155 . 
   Referring to  FIG. 7 , the metal sheet layer  153   b  may have a bent portion at its end bent toward the display panel  50 . This bent portion of the metal sheet layer  153   b  contacts the display panel  50 , and the space between the chassis base  11  and the bent portion of the metal sheet layer  153   b  is filled with the EMI sponge  155 . 
   Referring to  FIG. 8 , an end of the metal sheet layer  153   b  may extend to the adhesive element  54  so as to protrude from the heat dissipating layers  153   a  and  153   c . In this case, the EMI sponge  150  is disposed on both sides of the extended end of the metal sheet layer  153   b.    
   In  FIGS. 6  thru  8 , the metal sheet layer  153   b  and the display panel  50  are electrically grounded to the chassis base  11 . Accordingly, electromagnetic waves generated during the operation of the display panel  50  are captured by the metal sheet layer  153   b , and are discharged through the chassis base  11  to the rear of a display module. 
   The heat dissipation structure described above can be used for any display panel that generates heat during operation, such as a plasma display panel that generates a lot of heat during operation, since a high voltage is applied to a plasma display panel and an image is displayed in a plasma display panel using plasma discharge. 
   As described above, according to the present invention, a heat dissipation structure in which a heat dissipating sheet has a multi-layer structure can be implemented by interposing a metal sheet layer between heat dissipating sheets, and therefore heat generated during the operation of the display panel is efficiently transmitted to the chassis base and is discharged. 
   In addition, the heat dissipation structure according to the present invention discharges electromagnetic waves generated during the operation of the display panel to the rear of the chassis base, thus effectively shielding the electromagnetic waves not only from the user, but also from circuit elements on a driving circuit board disposed on the rear side of the chassis base. 
   While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.