Patent Publication Number: US-2007108909-A1

Title: Plasma display module

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a plasma display module. More particularly, the present invention relates to a plasma display module having a grounding structure for electrodes.  
      2. Description of the Related Art  
      Plasma display modules, which may be flat display modules for displaying images using a gas discharge phenomenon, may provide various advantages, such as high display capacity, high luminance, high contrast, low generation of afterimages, and a wide-range viewing angle. Plasma display modules have attracted considerable attention as next-generation flat display modules because they may be thin and large in size as compared to other flat display panels.  
       FIG. 1  illustrates a diagram of a plan view of a conventional plasma display module. The plasma display module may include a plasma display panel  30  having a first panel  10  and a second panel  20 . The plasma display module may include an X driver, a Y driver, and an address driver that apply driving signals to the plasma display panel  30 . A plurality of electrodes X, Y, and A that contribute to display discharge may be arranged on the plasma display panel  30 . For example, a plurality of sustain electrodes X and a plurality of scan electrodes Y may extend parallel to each other and may be arranged on the first panel  10 . A plurality of address electrodes A that perpendicularly cross the sustain electrodes X and the scan electrodes Y may be arranged on the second panel  20 . The sustain electrodes X and the scan electrodes Y may be electrically coupled to the X driver and the Y driver to receive driving signals from the X driver and the Y driver, respectively. The address electrodes A may be electrically coupled to the address driver to receive an address signal from the address driver.  
      The sustain electrodes X and the scan electrodes Y may form a plurality of sustain electrode X and scan electrode Y pairs. A display discharge may occur between a sustain electrode X and a scan electrode Y pair. An area portion where the sustain electrode X and the scan electrode Y pair perpendicularly cross an address electrode A may be defined as a sub-pixel  31 . A plurality of sub-pixels  31  may be arranged horizontally and vertically in a space  35 . The space  35  may be an area where the first panel  10  and the second panel  20  overlap with each other.  
      A pixel may include a plurality of sub-pixels  31 . For example, three sub-pixels emitting, for example, different colors, such as red (R), green (G), and blue (B) sub-pixels  31  may constitute a pixel.  
      The plasma display panel  30  may be driven during a repetition of a driving period. In an exemplary operation, the driving period may include a reset period, an address period, and a sustain period. During the reset period, the charge states of all of the sub-pixels  31  may become uniform. During the address period, address discharge may occur in selected sub-pixels  31  by applying sequentially-controlled address signals to the address electrodes A. Wall charges may be accumulated in the sub-pixels  31  that have undergone address discharge. As a result, a predetermined wall voltage may be formed in the selected sub-pixels  31 . During the sustain period, predetermined voltage pulses may be applied to all of the sustain electrodes X and the scan electrodes Y. The voltage pulses may include, for example, a sustain discharge voltage that alternates with a ground voltage. Accordingly, a voltage equal to or higher than a discharge start voltage may be formed in the sub-pixels  31 . That is, the predetermined wall voltage and the sustain discharge voltage may form a discharge start voltage so that display discharge may be generated.  
      As described above, in a conventional plasma display module, voltage pulses may be applied to the sustain electrodes X and the scan electrodes Y. That is, both the X driver and the Y driver may apply driving signals to the sustain electrodes X and the scan electrodes Y, respectively. Each of the X driver, Y driver, and the address driver may be a high-priced circuit board. The high-priced circuit board may include a plurality of mounted circuits. Thus, manufacturing costs for plasma display modules have been increasing.  
      Additionally, the circuit board of each driver may generate significant heat according to its operation. If this high heat is not rapidly removed, it may accumulate and degrade the circuits on the circuit board and hinder the operation of the plasma display module. Hence, a special heat conduction structure may be required to prevent heat from accumulating in a narrow enclosure where a plurality of circuit boards may be integrated. Further, a circuit board that generates a periodical electrical signal may produce noise and/or vibrations. The noise and/or vibrations may propagate, and the quality of displaying images by the plasma display module may be degraded. Thus, a plasma display module having a plurality of circuit boards may require a special vibration damping structure for reducing noise and/or vibrations.  
     SUMMARY OF THE INVENTION  
      The present invention is therefore directed to a plasma display module that substantially overcomes one or more of the problems due to the limitations and disadvantages of the related art.  
      It is therefore a feature of an exemplary embodiment of the present invention to provide a plasma display module having a grounding structure for electrodes.  
      It is therefore another feature of an exemplary embodiment of the present invention to provide a plasma display module with a heat conduction sheet and a conductive chassis base that may be employed as a low cost means for conducting heat and/or damping vibrations.  
      At least one of the above and other features and advantages of the present invention may be realized by providing a plasma display module that may include a chassis base having a grounding area, a plasma display panel attached to the chassis base, a circuit board configured to supply driving signals to the plasma display panel, a first driving cable connecting the circuit board to the plasma display panel, and a second driving cable having a first end connected to the plasma display panel and a second end connected to a rear surface of the plasma display panel, wherein the second driving cable forms a substantially round curve between the first end and the second end, and the substantially round curve may contact and may be grounded to the grounding area of the chassis base.  
      The second driving cable may include a conductive pattern layer having a first surface and a second surface, and a cover film that may cover the first surface and a portion of the second surface of the conductive pattern layer, the second surface of the conductive pattern layer may not be covered at the substantially round curve so as to electrically contact the grounding area of the chassis base.  
      The plasma display panel may include an arrangement of electrodes and the first end of the second driving cable may connect to an electrode.  
      The plasma display panel may include a front panel and a rear panel, and the first end of the second driving cable may be connected to the electrode at a rear surface of the front panel. The first end of the second driving cable may be connected to the electrode by an anisotropic conductive adhesive.  
      The arrangement of electrodes may include a scan electrode and a sustain electrode, the first end of the second driving cable may connect to the sustain electrode and the first driving cable may connect to the scan electrode.  
      The plasma display module may be driven by a repetition of a driving period, and the grounding area of the chassis base may provide a ground voltage to the sustain electrode during the driving period.  
      The adhesive tape may be positioned along a perimeter portion of the rear surface of the rear panel.  
      The second end of the driving cable may be attached to a rear surface of the rear panel by a dual adhesive tape. The dual adhesive tape may be positioned along a perimeter portion of the rear surface of the rear panel. The dual adhesive tape may attach the plasma display panel to the chassis base.  
      The grounding area of the chassis base may be a front surface of the chassis base.  
      At least one of the above and other features and advantages of the present invention may be realized by providing a plasma display module that may include a chassis base having a grounding area, a plasma display panel attached to the chassis base, a circuit board configured to supply driving signals to the plasma display panel, a first driving cable connecting the circuit board to the plasma display panel, and a second driving cable having a first end and a second end connected to the plasma display panel, where a segment of the second driving cable between the first end and the second end may contact and may be grounded to the grounding area of the chassis base.  
      The plasma display panel may include a front panel and a rear panel, and the segment of the second driving cable may wrap from a rear side of the front panel to a rear side of the rear panel.  
      The second driving cable may include a conductive layer and cover films covering both sides of the conductive layer, and the segment may have a portion of the cover film removed so that electrical contact is made between the segment and the grounding area of the chassis base.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The above and other features and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:  
       FIG. 1  illustrates a diagram of a plan view of a conventional plasma display module;  
       FIG. 2  illustrates a diagram of a plan view of a plasma display module according to a first exemplary embodiment of the present invention;  
       FIG. 3  illustrates a diagram of a partial, exploded perspective view of the first exemplary plasma display module illustrated in  FIG. 2 ;  
       FIG. 4  illustrates a diagram of a partial, exploded perspective view of a first exemplary grounding structure that may be employed by the first exemplary plasma display module illustrated in  FIG. 3 ;  
       FIG. 5  illustrates a diagram of a partial, cross-sectional view taken along the line V-V of the exemplary grounding structure illustrated in  FIG. 4 , including an enlarged perspective view of an exemplary cable/chassis base arrangement; and  
       FIG. 6  illustrates a diagram of a partial, exploded perspective view of a second exemplary grounding structure. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Korean Patent Application No. 10-2005-0108298, filed on Nov. 12, 2005, in the Korean Intellectual Property Office, and entitled: “Plasma Display Module,” is incorporated by reference herein in its entirety.  
      The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are illustrated. The invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.  
      In the figures, the dimensions of regions may be exaggerated for clarity of illustration. It will also be understood that when an element is referred to as being “on” another element, it can be directly on the other element, or intervening elements may also be present. In addition, it will also be understood that when an element is referred to as being “between” two elements, it can be the only element between the two elements, or one or more intervening elements may also be present. Like reference numerals refer to like elements throughout.  
      Spatially relative terms, such as “beneath,” “below,” “under,” “lower,” “above,” “upper,” “front,” “rear,” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the accompanying figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, for example, the term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein interpreted accordingly.  
      The terminology used herein is for the purpose of describing particular exemplary embodiments only, and is not intended to be limiting of the present invention. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.  
       FIG. 2  illustrates a diagram of a plan view of a plasma display module according to an exemplary embodiment of the present invention. Referring to  FIG. 2 , the plasma display module may include a plasma display panel  130 . The plasma display panel  130  may include a first panel  110  and a second panel  120  facing each other. Sustain electrodes X, scan electrodes Y, and address electrodes A may be arranged on the plasma display panel  130 . The sustain electrodes X and the scan electrodes Y may extend in parallel to each other. The address electrodes A may extend perpendicular to the sustain electrodes X and the scan electrodes Y. Y and A drivers may be electrically connected to the scan electrodes Y and address electrodes A, respectively. A connection of the sustain electrodes X will be discussed in greater detail below.  
      A plurality of sub-pixels  131  may be arranged horizontally and vertically in a space  135 . The space  135  may be an area where the first panel  110  and the second panel  120  overlap with each other. Each of the sub-pixels  131  may be defined as an area where a sustain electrode X and a scan electrode Y cross an address electrode A.  
      A pixel may include a plurality of sub-pixels  131 . For example, three sub-pixels  131  emitting, for example, different colors, such as red (R), green (G), and blue (B), may constitute a pixel. Although not illustrated in  FIG. 2 , barrier ribs may be formed between adjacent sub-pixels  131 . The barrier ribs may define the sub-pixels  131  as independent discharge spaces.  
      Terminal areas  110   a,    110   b,  and  120   a  may be on the outer perimeter of the space  135 . For example, the first panel  110  may include the terminal area  110   a  at its edge. The scan electrodes Y and the Y driver may be electrically coupled to each other on the terminal area  110   a.  The scan electrodes Y may receive driving signals from the Y driver. The second panel  120  may include the terminal area  120   a  at its edge. The address electrodes A and the address driver may be electrically coupled to each other on the terminal area  120   a.  The address electrodes A may receive address signals from the address driver. The first panel  110  may further include the terminal area  110   b  at its other edge. The sustain electrodes X may be grounded on the terminal area  110   b.  That is, a ground voltage Vg may be applied to the sustain electrodes X. Thus, an X driver may not be necessary.  
      By this exemplary arrangement, various discharges may occur. The sustain electrodes X and the scan electrodes Y may form a plurality of sustain electrode X and scan electrode Y pairs. The address electrodes A may generate address discharge in selected sub-pixels  131 . Address discharge may occur between, for example, the scan electrodes Y and the address electrodes A. The address discharge may facilitate display discharge between the sustain electrodes X and the scan electrodes Y. An image may be formed by display discharge occurring in each sustain electrode X and scan electrode Y pair.  
      In a conventional plasma display module, during a sustain period, a voltage pulse may be alternately applied to the sustain electrodes X and the scan electrodes Y. That is, during the sustain period, a sustain discharge voltage and a ground voltage may be alternately applied to each of the sustain electrodes X and the scan electrodes Y. In the present invention, however, during the sustain period, an alternating pulse may be applied to only the scan electrodes Y, and the ground voltage Vg may be applied to the sustain electrodes X.  
      In the conventional plasma display module, the voltage pulse may include a positive sustain discharge voltage and a ground voltage. The voltage pulse may be applied to the sustain electrodes X and the scan electrodes Y. However, according to the present invention, an alternating pulse may include, for example, a positive sustain discharge voltage and a negative sustain discharge voltage. The alternating pulse may be applied to the scan electrodes Y, and a ground voltage Vg may be applied to the sustain electrodes X. In this way, a sustain discharge voltage having the same voltage difference as that employed in the conventional plasma display module may be applied between the sustain electrodes X and the scan electrodes Y of the plasma display module according to the present invention, while driving only the scan electrodes Y.  
       FIG. 3  illustrates a diagram of a partial, exploded perspective view of the plasma display module illustrated in  FIG. 2 . Referring to  FIG. 3 , the plasma display module may include the plasma display panel  130 . The plasma display panel  130  may include the first panel  110  and the second panel  120 . A chassis base  160  may be arranged to a rear of the plasma display panel  130  as a supporting structure for the plasma display panel  130 . A heat conduction sheet  140  may be interposed between the plasma display panel  130  and the chassis base  160 . The heat conduction sheet  140  may transmit heat generated by the plasma display panel  130  to the chassis base  160 . The plasma display panel  130  may be coupled to the chassis base  160  by an adhesive element, such as a dual adhesive tape  145 . The dual adhesive tape  145  may be attached along edges of the heat conduction sheet  140 .  
      A plurality of electrodes X, Y, and A may be arranged on the plasma display panel  130 . A plurality of driving cables  150 X,  150 Y, and  150 A may extend rearwards from edges of the plasma display panel  130  and transmit signals to the electrodes X, Y, and A. The driving cables  150 X may be X driving cables that may transmit a ground voltage to the sustain electrodes X. The driving cables  150 Y may be Y driving cables that may be coupled to the scan electrodes Y to transmit a controlled driving signal to the scan electrodes Y. The driving cables  150 A may be address driving cables that may be coupled to the address electrodes A to transmit an address signal to the address electrodes A. Each of the driving cables  150 X,  150 Y, and  150 A may include a plurality of conductive patterns. The conductive patterns of the driving cables  150 X,  150 Y, and  150 A may be coupled to the electrodes X, Y, and A. It is to be understood, while  FIG. 3  illustrates four ribbon-type driving cables  150 X, the number and type of driving cables may be different.  
      The chassis base  160  may act as a heat conduction plate for the plasma display panel  130 . The chassis base  160  may also have a ground connection area. The chassis base  160  may include metal having high heat and high electrical conductivities, such as aluminum (Al). Since the chassis base  160  may support the plasma display panel  130  at its front side and support circuit boards  170  at its rear side, the chassis base  160  may have vertically bent portions  161  along its edges. The vertically bent portions  161  may enhance the support capability of the chassis base  160 . In addition, special reinforcing members  163  may be on the rear surface of the chassis base  160 .  
      A plurality of circuit boards  170  for driving the plasma display panel  130  may be arranged on the rear surface of the chassis base  160 . In one implementation, the plurality of circuit boards may be coupled to a plurality of coupling bosses  165  formed on the rear surface of the chassis base  160 . The plurality of coupling bosses  165  may protrude rearwards by a predetermined length from the rear surface of the chassis base  160 .  
      Some of the circuit boards  170  may be drivers for applying controlled driving signals to the scan electrodes Y and the address electrodes A of the plasma display panel  130 . For example, a circuit board  170 Y may correspond to the Y driver and may be coupled to the Y driving cables  150 Y, as illustrated in  FIG. 2 . A circuit board  170 A may correspond to the address driver and may be coupled to the address driving cables  150 A, as illustrated in  FIG. 2 . In another implementation, the circuit boards  170 Y and  170 A may be replaced by a single circuit board (not illustrated), and the driving cables  150 Y and  150 A may be coupled to the single circuit board in a suitable fashion. In another implementation, although not illustrated, the circuit boards  170 Y and  170 A may be replaced by at least two circuit boards electrically coupled to each other. In addition to the circuit boards  170 Y and  170 A, the circuit boards  170  may further include a switching mode power supply (SMPS) circuit board, a logic circuit board, etc., that may perform different functions.  
      The driving cables  150 X, however, may not be coupled to any of the circuit boards  170 . Rather, the driving cables  150 X may instead be grounded to the chassis base  160 , as discussed in greater detail below.  
      Referring to  FIGS. 4 and 5 , first ends  151  of the driving cables  150 X may be electrically coupled to the sustain electrodes X of the first panel  110 . An anisotropic conductive adhesive  180  may be interposed between the sustain electrodes X and the driving cables  150 X. The anisotropic conductive adhesive  180  may be a conductive material that applies conductivity only in a direction in which the conductive material is pressed. The first ends  151  of the driving cables  150 X may be pressed on the sustain electrodes X with the anisotropic conductive adhesive  180  interposed between them. In this way, the first ends  151  of the driving cables  150 X and the sustain electrodes X may be electrically coupled to each other.  
      The first ends  151  of the driving cables  15 OX may extend toward the rear surface of the plasma display panel  130  by forming an arch, such as round curves  153 . Second ends  152  of the driving cables  150 X may be attached to the rear surface of the plasma display panel  130  with, e.g., an adhesive tape  190 . That is, the driving cables  150 X may be interposed between the adhesive tape  190  and the plasma display panel  130 . The adhesive tape  190  may be tape having a single adhesive side. A double adhesive tape  145  may also be attached to the rear surface of the plasma display panel  130 . Once the first and the second ends  151  and  152  of the driving cables  150 X are attached on the plasma display panel  130 , and the round curves  153  are formed, the chassis base  160  may be coupled to the plasma display panel  130  as illustrated in  FIG. 5 . The round curves  153  of the driving cables  150 X may be pressed to the chassis base  160  and contact the chassis base  160 .  
      Referring to  FIG. 5 , the driving cable  150 X may include a conductive pattern layer  150   b  and cover films  150   a  and  150   c.  The conductive pattern layer  150   b  may be, for example, a thin layer of copper. The cover films  150   a  and  150   c  may be for insulating both sides of the conductive pattern layer  150   b.  A portion of the cover film  150   c  may be removed so that the conductive pattern layer  150   b  is exposed. That is, a portion of the cover film  150   c  corresponding to the round curve  153  may be removed. The exposed conductive pattern layer  150   b  may be pressed to contact the chassis base  160 . In this way, the driving cable  150 X may be directly grounded to the chassis base  160 . That is, an area of the round curve  153  of the driving cable  150 X may be grounded by the chassis base  160 . The chassis base  160  providing a ground voltage Vg.  
       FIG. 6  illustrates a diagram of a partial, exploded perspective view of a second exemplary grounding structure. Like reference numerals are provided to elements that execute the same functions as the elements described above.  
      Referring to  FIG. 6 , the plasma display panel  130  may be coupled to the chassis base  160  by the dual adhesive tape  145  interposed between the plasma display panel  130  and the chassis base  160 . First ends  151  of driving cables  150 X may be electrically coupled to sustain electrodes X of a first panel  110 . The first ends  151  of the driving cables  150 X may extend toward the rear surface of the plasma display panel  130  by forming round curves  153 . Second ends  152  of the driving cables  150 X may be attached to the rear surface of the plasma display panel  130 . The dual adhesive tape  145  may be interposed between second ends  152  of the driving cables  150 X and the chassis base  160 . The driving cables  150 X that extend from the first ends  151  to the second ends  152  may form the round curves  153 . The round curves  153  of the driving cables  150 X may include the conductive pattern layer  150   b  and cover films  150   a  and  150   c.  A portion of the cover film  150   c  may be removed and the exposed conductive pattern layer  150   b  may contact the chassis base  160  so that the driving cables  150 X may be directly grounded to the chassis base  160 .  
      In this second exemplary embodiment, the dual adhesive tape  145  may attach the plasma display panel  130  to the chassis base  160  and attach the driving cables  150 X to the plasma display panel  130 . Accordingly, in the second exemplary embodiment, special elements, such as separate adhesive tapes for attaching the driving cables  150 X to the plasma display panel  130  may not be required. That is, the dual adhesive tape  145  may be attached to the plasma display panel  130  to couple the plasma display panel  130  to the chassis base  160  and also attach the second ends  152  of the driving cable  150 X to the plasma display panel  130 . Thus, the number of steps required to form the plasma display module may be reduced.  
      In contrast to conventional plasma display modules, a plasma display module according to the present invention may drive a plasma display panel using a fewer number of circuit boards. That is, a driving circuit board for driving electrodes may be omitted by employing the grounding structure of the present invention. Thus, a plasma display module according to the present invention may be manufactured at a reduced cost. Additionally, design and manufacturing costs associated with controlling heat and vibrations generated by the circuit boards may be reduced.  
      Exemplary embodiments of the present invention have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. Accordingly, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.