Patent Publication Number: US-RE42233-E

Title: Plasma display apparatus

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a plasma display apparatus, and more particularly, to a plasma display apparatus for connecting a film-type front filter. 
     2. Description of the Related Art 
     Plasma display panel (hereinafter referred to as “PDP”) generally displays an image including character or graphic by exciting phosphor using ultraviolet rays with a wavelength of 147 nm, which is generated during a gas discharge of an inert mixture gas, such as He+Xe, Ne+Xe, He+Ne+Xe or the like. This PDP has easy slimness and large-sized characteristics, and provides a greatly improved picture quality thanks to the recent technology development. In particular, three-electrode alternating current (AC) surface discharge type PDP has advantages of a low voltage operation and a long life since wall charges stored on a surface in the course of discharge protect electrodes from sputtering generated by the discharge. 
       FIG. 1  is a view illustrating a discharge cell of a conventional three-electrode alternating current (AC) surface discharge type plasma display panel. 
     Referring to  FIG. 1 , a discharge cell of the three-electrode AC surface discharge type PDP includes a scan electrode (Y) and a sustain electrode (Z) formed on an upper substrate  10 , and an address electrode (X) formed on a lower substrate  18 . Each of the scan electrode (Y) and the sustain electrode (Z) includes transparent electrodes  12 Y and  12 Z and metal bus electrodes  13 Y and  13 Z having line widths narrower than line widths of the transparent electrodes  12 Y and  12 Z formed at one-sided edge regions of the transparent electrodes  12 Y and  12 Z. 
     The transparent electrodes  12 Y and  12 Z are generally formed of Indium-Tin-Oxide (Hereinafter, referred to as “ITO”) on the upper substrate  10 . The metal bus electrodes  13 Y and  13 Z are generally formed of chrome (Cr) on the transparent electrodes  12 Y and  12 Z to function to reduce a voltage drop caused by the transparent electrodes  12 Y and  12 Z having high resistance. An upper dielectric layer  14  and a passivation film  16  are layered on the upper substrate  10  having the scan electrode (Y) and the sustain electrode (Z) formed in parallel with each other. The wall charge generated at the time of plasma discharge is stored in the upper dielectric layer  14 . The passivation film  16  prevents the upper dielectric layer  14  from being damaged due to the sputtering generating at the time of the plasma discharge and also, enhances an emission efficiency of a secondary electron. Magnesium oxide. (MgO) is generally used as the passivation film  16 . A lower dielectric layer  22  and a barrier  24  are formed on the lower substrate  18  having the address electrode (X), and a fluorescent layer  26  is coated on a surface of the lower dielectric layer  22  and the barrier  24 . The address electrode (X) is formed in a direction of crossing with the scan electrode (Y) and the sustain electrode (Z). The barrier  24  is formed in parallel with the address electrode (X) to prevent the visible ray and the ultraviolet ray caused by the discharge from being leaked to an adjacent discharge cell. The fluorescent layer  26  is excited by the ultraviolet ray generated due to the plasma discharge to radiate any one visible ray of red, green or blue. The inert mixed gas for the discharge such as He+Xe, Ne+Xe, He+Ne+Xe and the like is injected into a discharge space of the discharge cell provided between the upper/lower substrates  10  and  18  and the barrier  24 . 
     In the PDP, one frame is divided for time-division driving into several sub-fields having different light-emitting times so as to embody a gray level of the image. Each of the sub-fields is divided into a reset period for which an entire screen is initialized, an address period for which a scan line is selected and a specific cell is selected at the selected scan line, and a sustain period for which the gray level is embodied depending on the light-emitting times. 
     For example, in case that the image is expressed using a 256 gray level as in  FIG. 2 , a frame period (16.67 ms) corresponding to 1/60 second is divided into eight sub-fields (SF 1  to SF 8 ). Also, each of the eight sub-fields (SF 1  to SF 8 ) is again divided into a reset period, an address period and a sustain period. Herein, the reset and address periods of each sub-field are identical every sub-field, whileas the sustain period is increased in a ratio of 2 n  (n=0, 1, 2, 3, 4, 5, 6, 7) at each of the sub-fields. 
     In the above-driven PDP, a front filter for shielding an electromagnetic interference and also preventing an external light from being reflected is installed on a front surface of the upper substrate  10 . 
       FIG. 3  is a schematic section view illustrating a portion of a conventional plasma display apparatus. 
     Referring to  FIG. 3 , the conventional plasma display apparatus includes a panel  32  where the upper substrate  10  and the lower substrate  18  are attached to each other with a gap therebetween, a front filter  30  installed at a front surface of the panel  32 , a chassis base  36  for supporting the panel  32  and also mounting a printed circuit board thereon, a heat sink plate  34  attached to a front surface of the chassis base  36 , a back cover  38  installed on a rear surface of the panel  32 , and a front cabinet  45  for electrically connecting the back cover  38  and the front filter  30 . 
     The front cabinet  45  includes a filter support portion  40  for electrically connecting the front filter  30  and the back cover  38 , and a support member  42  for fixing and supporting the front filter  30  and the back cover  38 . The filter support portion  40  supports the front filter  30  such that a rear surface of the front filter  30  is spaced away from the panel  32 . Further, the filter support portion  40  electrically connects the EMI shield film included in the front filter  30  to the back cover  38  grounded to a ground voltage source to discharge an EMI signal from the EMI shield film. Also, the filter support portion  40  prevents the EMI from being laterally emitted. 
     The printed circuit board mounted on the chassis base  36  supplies a driving signal to electrodes (for example, a scan electrode, a sustain electrode and an address electrode) of the panel  32 . For this, the printed circuit board includes various driving portions not shown. The panel  32  displays a certain image in response to the driving signal supplied from the printed circuit board. The heat sink plate  34  dissipates heat generated from the panel  32  and the printed circuit board. The back cover  38  protects the panel  32  from an external impact, and also shields an electromagnetic interference (Hereinafter, referred to as “EMI”) laterally emitted. 
     The front filter  30  shields the EMI and also, prevents an external light from being reflected. For this, the front filter  30  includes an antireflection coating  50 , an EMI shield film  54  and a near infrared ray (Hereinafter, referred to as “NIR”) shield film  56 . The front filter  30  additionally includes a glass and a color correction film  58 . Herein, an adhesive layer is formed between respective films  50 ,  52 ,  54 ,  56  and  58  of the front filter  30  to adhere respective films  50 ,  52 ,  54 ,  56  and  58  to one another. Generally, a color correction pigment is added to the adhesive layer to form the color correction film  58 . At this time, a structure of the front filter  30  can be a little varied depending on providers. 
     The antireflection coating  50  prevents incident light from being reflected to thereby enhance the contrast of the PDP. The antireflection coating  50  is formed on a front surface of the front filter  30 , and may be further formed on a rear surface of the front filter  30 . The optical characteristic film  52  lowers the brightness of red (R) and green (G) colors of the visible light applied from the panel  32 , and enhances the brightness of blue (B) color of the visible light thereby improving the optical characteristics of the PDP. 
     The glass  54  protects the front filter  30  from external impact. The glass  54  supports the front filter  30  such that the glass  54  may protect the front filter  30  from external impact. 
     The EMI shield film  56  screens the EMI to prevent the EMI applied from the panel from being released to the external. The NIR shield film  58  screens the NIR irradiated from the panel  32  to prevent the NIR from being irradiated more than the standard to the external so that signal transfer apparatuses may normally transfer a signal by the NIR as a remote controller. The EMI shield film  56  and the NIR shield film  58  can be configured in one layer. 
     The front filter  30  is electrically connected to the back cover  38  through the filter supporter  40  as shown in FIG.  5 . The filter supporter  40  is connected to an edge portion of the rear surface of the front filter  30 . The filter supporter  40  is electrically connected to at least one of the EMI shield film  56  and the NIR shield film  58 . Therefore, the filter supporter  40  connects the front filter  30  to the back cover  38  to thereby screen the EMI and/or the NIR. 
     The conventional front filter  30  is protected from external impacts by glass  54 . Such front filter  30  is called a glass-type entire filter. If the glass  54  is inserted into the front filter  30 , the front filter  30  becomes thicker, heavier and more expensive. 
     To solve the above-mentioned problems, the front filter without the glass had been suggested as shown in FIG.  6 . The front filter is called film-type front filter. 
     The film-type front filter  60  includes an antireflection coating  62 , an optical characteristic film  64 , an EMI shield file  66  and an NIR shield film  68 . Adherence layers are formed between films  62 ,  64 ,  66  and  68  of the film-type front filter  60  such that the films  62 ,  64 ,  66  and  68  are attached to adjacent ones. In general, the optical characteristic film  64  is formed by inserting a specific material into the adherence layers. The structure of film-type front filter  60  can be modified variously according to a user company. In  FIG. 6 , the adherence layer is not shown for the convenience for the description and the optical characteristic film is depicted as a specific layer. 
     The antireflection coating  62  is formed on a front surface of the film-type front filter  60  to prevent incident light from being reflected. The antireflection coating  62  may be further formed on a rear surface of the film-type front filter  60 . The optical characteristic film  64  lowers the brightness of red (R) and green (G) colors of the visible light applied from the panel  32 , and enhances the brightness of blue (B) color of the visible light thereby improving the optical characteristics of the PDP. 
     The EMI shield film  66  screens the EMI to prevent the EMI applied from the panel from being released to the external. The NIR shield film  68  screens the NIR irradiated from the panel  32  to prevent the NIR from being irradiated more than the standard to the external so that signals may be normally transferred from a remote controller to a panel  32 . The EMI shield film  66  and the NIR shield film  68  can be configured in one layer. 
     The film-type front filter  60  is thinner, lighter and cheaper than the front filter  30  with the glass  54 . 
     However, a plasma display apparatus with a film-type front filter and a method for manufacturing the same have not been suggested so that the film-type front filter is not widely used. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to a plasma display apparatus that substantially obviates one or more problems due to limitations and disadvantages of the related art. 
     An object of the present invention is to provide a plasma display apparatus to which a film-type front filter can be easily connected. 
     Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. 
     To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a plasma display apparatus includes a panel formed by attaching an upper substrate to a lower substrate, an front filter attached to an entire surface of the panel and including extension extending by predetermined lengths from edges of the panel in omni-directions, a back cover formed on a rear surface of the chassis base, and a filter supporter for electrically connecting the extension to the back cover. 
     The extension may farther extend by 2 mm-300 mm from the edges of the panel, and may be formed of the same material as the film-type entire filter and integrated with the film-type entire filter. 
     The film-type entire filter may further include metallic material formed to surround the extension. 
     The filter supporter may include a clip for rotating with respect to a guide member in pitching direction, and a flange for connecting the filter supporter with the clip. 
     It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this applications, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings: 
         FIG. 1  is a perspective view of a discharge cell of a PDP; 
         FIG. 2  illustrates a frame to represent 256 gray levels in a general PDP; 
         FIG. 3  is a schematic cross-sectional view of a portion of a plasma display apparatus of the related art; 
         FIG. 4  is a schematic cross-sectional view of an front filter of  FIG. 3 ; 
         FIG. 5  illustrates that a filter supporter is attached to an front filter of  FIG. 3 ; 
         FIG. 6  illustrates a film-type front filter of the related art schematically; 
         FIG. 7  illustrates a portion of a plasma display apparatus according to an embodiment of the present invention schematically; and 
         FIG. 8  is a detailed perspective view of a filter supporter of FIG.  7 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
       FIG. 7  illustrates a portion of a plasma display apparatus according to an embodiment of the present invention schematically. 
     Referring to  FIG. 7 , a plasma display apparatus of the present invention includes a panel  72 , a film-type front filter  74 , a chassis base, a heat sink plate, a back cover, and a filter supporter  76 . The panel  72  is formed by attaching an upper substrate to a lower substrate. The film-type front filter  74  is attached to an entire surface of the panel  72 . The chassis base supports the panel  72  and has a PUB upon which various drivers are installed. The heat sink plate is attached to the entire surface of the chassis base. The back cover is formed on a rear surface of the chassis base. The filter supporter  76  connects the back cover electrically to the film-type front filter  74 . Though the chassis base, the heat sink plate, the back cover and a front cabinet are not shown in  FIG. 7 , they must be fully understood referring to FIG.  3 . 
     The film-type front filter  74  may be larger area the panel  72 . For example, the film-type front filter  74  may be provided with extension  79  extending by predetermined lengths from edges of the panel in omni-directions. The extension  79  may farther extend by 2 mm-300 mm from the edges of the panel  72 . Note that the extension  79  extends in omni-directions. Accordingly, the film-type front filter  74  may extend by 4 mm-600 mm horizontally and vertically. The extension  79  may be formed of the same material as the filter supporter and integrated with the filter supporter. 
     To achieve this, metallic material  78  is formed to surround the extensions  79 . The metallic material  78  may be any conducting material. The metallic material  78  is shaped of a plate and may be attached to the extension to surround the extension. To enhance the adherence between the metallic material  78  and extension, additional adherent agent may be coated on inner surface of the metallic material  78 . 
     The Metallic material  79  may be electrically connected to at least one film of an NIR shield film and an EMI shield film of the film-type front filter  74 . Therefore, the electrical signal generated from the NIR shield film and the EMI shield film may be released to the external through the metallic material  79 . 
     Accordingly, the metallic material  79  attached to the extension  79  may be electrically connected to the filter supporter  76 . 
     To achieve this, the filter supporter is provided with a clip  80  and a flange  82  thereon as shown in FIG.  8 . The clip  80  may rotate with respect to a predetermined shaft in pitching directions. The flange  82  connects the filter supporter  76  with the clip  80 . The flange includes a first projection  86 , a second projection  87 , a guide member  88  and a coil spring  84 . The first projection  86  extends from the filter supporter  76  and has a first hole (not shown) penetrating the first projection  76 . The second projection  87  extends from the clip and has a second hole (not shown) penetrating the second projection  87 . The guide member  88  penetrates the first and second holes and fixedly connects the first and second projections  86  and  87 . The coil spring  84  is formed to surround the guide member  88  so as to give elastic force to the clip  80 . 
     The clip  80  may be electrically connected to the filter supporter  76  through the flange  82 . 
     Accordingly, when an end of the clip  80  is rotated downwards, the other end of the clip  80  is rotated upwards to be widened. Then, the metallic material  78  attached to the extension  79  of the film-type entire filter  74  is mounted on the filter supporter  26 . Then, if the clip  80  is loosened, the end of the clip  80  is rotated upwards and the other end of the clip  80  is rotated downwards such that the metallic material is fixed. Therefore, the clip  80  is electrically connected to the metallic material. 
     Consequently, the extension  79  of the film-type entire filter  74  is electrically connected to the metallic material  78  and the metallic material  78  may be electrically connected to the clip  80  and the filter supporter  76 . The clip  80  may be electrically connected to the filter supporter  76  through the flange  82 . 
     Therefore, the NIR signal or the EMI signal generated from the film-type front filter  74  is transferred to the filter supporter  76  to be released to the external via the metallic material  78 , the clip  80  and the flange  82 . 
     In this embodiment of the present invention, the film-type front filter  74  may be electrically connected to the filter supporter  76  by the clip  80  and the flange  82  formed on the filter supporter  76 . The film-type front filter  74  may further include an extension  79  such that the area where the film-type front filter  74  contacts the filter supporter  76  can be more occupied. Therefore, the NIR signal or the EMI signal can be more rapidly released to the external. 
     The extension  79  extending from the panel  72  is provided on the film-type front filter  74  to connect an end of the extension  79  to the filter supporter  76  by the clip  80 . The filter supporter  76  is separated from the panel  72  by a predetermined distance such that the panel  72  may be protected from the impact applied to the filter supporter  76 . 
     As described above, according to the present invention, the extension is formed to have the film-type entire filter whose area is larger than the panel. Then, the extension is surrounded by the metallic material. The extension of the film-type front filter may be contacted to the filter supporter using the clip provided on the filter supporter such that the film-type entire filter may be easily connected to filter supporter 
     Accordingly, a filter supporter is connected to an end of the extension of the film-type entire filter such that the panel is separated the filter supporter by a predetermined distance and the panel is prevented from being damaged due to the impacts applied to the filter supporter  4 . 
     The filter supporter is connected to the extension of the film-type front filter with larger area. The NIR signal and the EMI signals generated by the film-type front filter may easily be released to the outside through the filter supporter. 
     It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.