Patent Publication Number: US-7719188-B2

Title: Plasma display apparatus

Description:
This Nonprovisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 10-2006-0074438 filed in Korea on Aug. 7, 2006 the entire contents of which are hereby incorporated by reference. 
     BACKGROUND 
     1. Field 
     This document relates to a plasma display apparatus. 
     2. Description of the Background Art 
     A plasma display apparatus includes a plasma display panel including a plurality of electrodes, and a driver supplying a predetermined driving signal to the electrodes of the plasma display panel. 
     The plasma display panel includes a phosphor layer inside a discharge cell partitioned by barrier ribs. The driver supplies the predetermined driving signal to the discharge cell through the electrodes. 
     When the driving signal generates the discharge inside the discharge cells, a discharge gas filled in the discharge cells generates vacuum ultraviolet rays, which thereby cause phosphors formed inside the discharge cells to emit light, thus displaying an image on the screen of the plasma display panel. 
     SUMMARY 
     In one aspect, a plasma display apparatus comprises a plasma display panel on which an image is displayed, and a filter positioned in front of the plasma display panel, wherein a discharge gas filled in the plasma display panel contains xenon (Xe) equal to or more than 10% based on total weight of the discharge gas, wherein the filter includes a base portion, and a pattern portion formed on the base portion, having a color darker than a color of the base portion. 
     In another aspect, a plasma display apparatus comprises a plasma display panel on which an image is displayed, and a filter positioned in front of the plasma display panel, wherein a discharge gas filled in the plasma display panel contains xenon (Xe) equal to or more than 10% based on total weight of the discharge gas, wherein the filter includes a base portion, and a pattern portion formed on the base portion, wherein the height of the base portion ranges from 1.01 to 2.25 times the height of the pattern portion. 
     In still another aspect, a plasma display apparatus comprises a plasma display panel on which an image is displayed, and a filter positioned in front of the plasma display panel, wherein a discharge gas filled in the plasma display panel contains xenon (Xe) equal to or more than 10% based on total weight of the discharge gas, wherein the plasma display panel includes a front substrate on which a first electrode and a second electrode are formed in parallel to each other, and a rear substrate on which a third electrode is formed to intersect the first electrode and the second electrode, wherein the filter includes a base portion, and a pattern portion formed on the base portion, wherein a lower width of the pattern portion is less than the closest distance between the first electrode and the second electrode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompany drawings, which are included to provide a further understanding of the invention and are incorporated on and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. 
         FIG. 1  illustrates one example of a configuration of a plasma display apparatus according to one embodiment; 
         FIGS. 2   a  and  2   b  illustrate one example of a structure of a plasma display panel of the plasma display apparatus according to one embodiment; 
         FIG. 3  illustrates the plasma display apparatus according to one embodiment further including a buffer between the plasma display panel and a filter; 
         FIG. 4  illustrates one example of a filter of the plasma display apparatus according to one embodiment; 
         FIGS. 5   a  to  5   e  illustrate a function of a pattern portion; 
         FIGS. 6   a  to  6   e  illustrate other forms of pattern portions; 
         FIGS. 7   a  and  7   b  illustrate a traveling direction of a pattern portion; 
         FIGS. 8   a  to  8   c  illustrate various types of pattern portions; 
         FIG. 9  illustrates one example of a case of using two or more pattern portions each having different patterns; 
         FIG. 10  illustrates another structure of a pattern portion; 
         FIGS. 11   a  and  11   b  illustrate an application example of a filter including a pattern portion; 
         FIGS. 12   a  and  12   b  illustrate a xenon (Xe) content based on total weight of a discharge gas and a pressure of the discharge gas; 
         FIG. 13  illustrates one example of a configuration of the plasma display apparatus according to one embodiment including a driver; 
         FIG. 14  illustrates a frame for achieving a gray level of an image displayed by the plasma display apparatus according to one embodiment; 
         FIG. 15  illustrates one example of an operation of the plasma display apparatus according to one embodiment; 
         FIGS. 16   a  and  16   b  illustrate another form of a rising signal and a second falling signal; and 
         FIG. 17  illustrates another type of a sustain signal. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Reference will now be made in detail embodiments of the invention examples of which are illustrated in the accompanying drawings. 
       FIG. 1  illustrates one example of a configuration of a plasma display apparatus according to one embodiment. 
     Referring to  FIG. 1 , the plasma display apparatus according to one embodiment includes a plasma display panel  100 , on which an image is displayed, and a filter  110  positioned in front of the plasma display panel  100 . 
     The filter  110  includes a base portion (not illustrated) and a pattern portion (not illustrated). The filter  110  will be described in detail later. 
       FIGS. 2   a  and  2   b  illustrate one example of a structure of a plasma display panel of the plasma display apparatus according to one embodiment. 
     Referring to  FIG. 2   a , the plasma display panel of the plasma display apparatus according to one embodiment includes a front substrate  201  and a rear substrate  211  which are coalesced with each other. On the front substrate  201 , a first electrode  202  and a second electrode  203  are formed in parallel to each other. On the rear substrate  211 , a third electrode  213  is formed to intersect the first electrode  202  and the second electrode  203 . 
     The first electrode  202  and the second electrode  203  generate a discharge inside discharge spaces (i.e., discharge cells), and maintain the discharges of the discharge cells. 
     An upper dielectric layer  204  for covering the first electrode  202  and the second electrode  203  is formed on an upper portion of the front substrate  201  on which the first electrode  202  and the second electrode  203  are formed. 
     The upper dielectric layer  204  limits discharge currents of the first electrode  202  and the second electrode  203 , and provides insulation between the first electrode  202  and the second electrode  203 . 
     A protective layer  205  is formed on an upper surface of the upper dielectric layer  204  to facilitate discharge conditions. The protective layer  205  may be formed by deposing a material such as magnesium oxide (MgO) on an upper portion of the upper dielectric layer  204 . 
     A lower dielectric layer  215  for covering the third electrode  213  is formed on an upper portion of the rear substrate  211  on which the third electrode  213  is formed. The lower dielectric layer  215  provides insulation of the third electrode  213 . 
     Barrier ribs  212  of a stripe type, a well type, a delta type, a honeycomb type, and the like, are formed on an upper portion of the lower dielectric layer  215  to partition the discharge spaces (i.e., discharge cells). A red (R) discharge cell, a green (G) discharge cell, and a blue (B) discharge cell, and the like, are formed between the front substrate  201  and the rear substrate  211 . 
     In addition to the red (R), green (G), and blue (B) discharge cells, a white (W) discharge cell or a yellow (Y) discharge cell may be further formed between the front substrate  201  and the rear substrate  211 . 
     Pitches of the red (R), green (G), and blue (B) discharge cells may be substantially equal to one another. However, the pitches of the red (R), green (G), and blue (B) discharge cells may be different from one another to control a white balance in the red (R), green (G), and blue (B) discharge cells. 
     In this case, the pitches of all of the red (R), green (G), and blue (B) discharge cells may be different from one another, or alternatively, the pitch of at least one of the red (R), green (G), and blue (B) discharge cells may be different from the pitches of the other discharge cells. For instance, a pitch of the red (R) discharge cell may be the smallest, and pitches of the green (G) and blue (B) discharge cells may be more than the pitch (a) of the red (R) discharge cell. 
     The pitch of the green (G) discharge cell may be substantially equal to or different from the pitch of the blue (B) discharge cell. 
     The plasma display panel according one embodiment may have various forms of barrier rib structures as well as a structure of the barrier rib  212  illustrated in  FIG. 2   a . For instance, the barrier rib  212  includes a first barrier rib  212   b  and a second barrier rib  212   a . The barrier rib  212  may have a differential type barrier rib structure in which the height of the first barrier rib  212   b  and the height of the second barrier rib  212   a  are different from each other, a channel type barrier rib structure in which a channel usable as an exhaust path is formed on at least one of the first barrier rib  212   b  or the second barrier rib  212   a , a hollow type barrier rib structure in which a hollow is formed on at least one of the first barrier rib  212   b  or the second barrier rib  212   a , and the like. 
     In the differential type barrier rib structure, a height h 1  of the first barrier rib  212   b  may be less than a height h 2  of the second barrier rib  212   a . Further, in the channel type barrier rib structure or the hollow type barrier rib structure, a channel or a hollow may be formed on the first barrier rib  212   b.    
     While the plasma display panel according to one embodiment has been illustrated and described to have the red (R), green (G), and blue (B) discharge cells arranged on the same line, it is possible to arrange them in a different pattern. For instance, a delta type arrangement in which the red (R), green (G), and blue (B) discharge cells are arranged in a triangle shape may be applicable. Further, the discharge cells may have a variety of polygonal shapes such as pentagonal and hexagonal shapes as well as a rectangular shape. 
     Each of the discharge cells partitioned by the barrier ribs  212  is filled with a predetermined discharge gas. The discharge gas contains xenon (Xe) equal to or more than 10% based on total weight of the discharge gas. The discharge gas may contain xenon (Xe) of 13-30% based on total weight of the discharge gas. 
     A gas pressure inside the discharge cell may be equal to 500 torr or 450 torr. 
     The discharge gas and the gas pressure will be described in detail later. 
     Phosphor layers  214  for emitting visible light for an image display when generating an address discharge are formed inside the discharge cells partitioned by the barrier ribs  212 . For instance, red (R), green (G) and blue (B) phosphor layers may be formed inside the discharge cells. 
     A white (W) phosphor layer and/or a yellow (Y) phosphor layer may be further formed in addition to the red (R), green (G) and blue (B) phosphor layers. 
     The thicknesses (widths) of the phosphor layers  214  formed inside the red (R), green (G) and blue (B) discharge cells may be substantially equal to one another. Or, the thickness of the phosphor layer  214  in at least one of the red (R), green (G) and blue (B) discharge cells may be different from the thicknesses of the phosphor layers  214  in the other discharge cells. For instance, the thickness of the phosphor layer in the green (G) or blue (B) discharge cell may be more than the thickness of the phosphor layer in the red (R) discharge cell. The thickness of the phosphor layer  214  in the green (G) discharge cell may be substantially equal to or different from the thickness of the phosphor layer  214  in the blue (B) discharge cell. 
     Although  FIG. 2   a  has illustrated and described a case where the first electrode  202  and the second electrode  203  each include a single layer, at least one of the first electrode  202  or the second electrode  203  may include a plurality of layers. This will be described in detail with reference to  FIG. 2   b.    
     Referring to  FIG. 2   b , the first electrode  202  and the second electrode  203  each include a plurality of layers, for example, two layers. 
     Light transmissivity and electrical conductivity of the first electrode  202  and the second electrode  203  need to be considered to emit light generated within the discharge cell to the outside of the plasma display panel and to secure driving efficiency. Accordingly, the first electrode  202  and the second electrode  203  each include transparent electrodes  202   a  and  203   a  made of a transparent material, for example, indium-tin-oxide (ITO), and bus electrodes  202   b  and  203   b  made of an opaque material, for example, Ag. 
     As above, since the first electrode  202  and the second electrode  203  each include the transparent electrodes  202   a  and  203   a , visible light generated within the discharge cell is effectively emitted to the outside of the plasma display panel. 
     Furthermore, in a case where the first electrode  202  and the second electrode  203  each include only the transparent electrodes  202   a  and  203   a , electrical conductivity of the transparent electrodes  202   a  and  203   a  is relatively low, thereby reducing driving efficiency. However, the first electrode  202  and the second electrode  203  further include the bus electrodes  202   b  and  203   b , the low electrical conductivity of the transparent electrodes  202   a  and  203   a  causing a reduction in the driving efficiency is compensated. 
     It should be noted that only one example of the plasma display panel of the plasma display apparatus according to one embodiment has been illustrated and described above, and the embodiment is not limited to the plasma display panel of the above-described structure. For instance, although the above description illustrates a case where the upper dielectric layer  204  and the lower dielectric layer  215  each are formed in the form of a single layer, at least one of the upper dielectric layer  204  and the lower dielectric layer  215  may be formed in the form of a plurality of layers. 
     A black layer (not illustrated) for absorbing external light may be further formed on the upper portion of the barrier rib  212  to prevent the reflection of the external light caused by the barrier rib  212 . 
     Further, another black layer (not illustrated) may be further formed at a predetermined position on the front substrate  201  corresponding to the barrier rib  212 . 
     The third electrode  213  formed on the rear substrate  211  may have a substantially constant width or thickness. Further, the width or thickness of the third electrode  213  inside the discharge cell may be different from the width or thickness of the third electrode  213  outside the discharge cell. For instance, the width or thickness of the third electrode  213  inside the discharge cell may be more than the width or thickness of the third electrode  213  outside the discharge cell. 
     In this way, the structure of the plasma display panel according to one embodiment may be changed in various ways. 
     Since the front substrate  210  described above is made of a glass material, it is a great likelihood of a damage to the front substrate  210  by an external impact. 
     To prevent the damage, a buffer is further formed between the plasma display panel  100  and the filter. The following is a detailed description of the buffer, with reference to  FIG. 3 . 
       FIG. 3  illustrates the plasma display apparatus according to one embodiment further including a buffer between the plasma display panel and a filter. 
     Referring to  FIG. 3 , one or more buffers  120  and  130  are formed between the plasma display panel  100  and the filter  110 . The buffers  120  and  130  may include a material such as resin or glass. 
     The buffers  120  and  130  absorb an impact applied to the plasma display panel  100  from the outside, thereby protecting the plasma display panel  100 . To more efficiently protect the plasma display panel  100 , at least one of thicknesses t 1  and t 2  of the buffers  120  and  130  may range from 200 μm to 400 μm. 
     The buffers  120  and  130  may include an impact resistance film. 
     For example, the buffer  120  may include an impact resistance film, and the buffer  130  may include a resin material. 
     While the number of buffers is two in  FIG. 3 , one, three or four buffers may be formed. The number of buffers may be controlled variously. 
       FIG. 4  illustrates one example of a filter of the plasma display apparatus according to one embodiment. 
     Referring to  FIG. 4 , the filter of the plasma display apparatus according to one embodiment includes a pattern portion  410  and a base portion  420 . 
     The pattern portion  410  is formed on the base portion  420 . The number of pattern portions  410  is plural, and the plurality of pattern portions  410  are positioned to be spaced with a predetermined distance therebetween. The pattern portion  410  includes a light absorption material. The light absorption material includes at least one of carbon, pigment, or dyes. 
     A refraction index of the base portion  420  may be more than a refraction index of the pattern portion  410 . For example, assuming that a refraction index of the pattern portion  410  is equal to a first refraction index, a refraction index of the base portion  420  is equal to a second refraction index more than the first refraction index. The base portion  420  may include a transparent material. 
     A color of the pattern portion  410  may be darker than a color of the base portion  420 . For example, the color of the pattern portion  410  may be black. As the pattern portion  410  goes toward the base portion  420 , the width of the pattern portion  410  gradually decreases. For example, the section shape of the pattern portion  410  is approximately an isosceles triangle. 
     Accordingly, one surface of the base portion  420  parallel to the base of the pattern portion  410  and the pattern portion  410  form a predetermined angle θ 1 . The angle θ 1  may be equal to or more than about 70° and less than about 90°. 
       FIGS. 5   a  to  5   e  illustrate a function of a pattern portion. 
     Referring to  FIG. 5   a , light generated at a point “a” positioned at the inside of the filter directly is emitted to the outside. Light generated at points “b” and “c” positioned at the inside of the filter is totally reflected by the pattern portion  410  and then emitted to the outside. 
     However, light entered from points “d” and “e” positioned at the outside of the filter is absorbed into the pattern portion  410 . This occurs because the refractive index of the pattern portion  410  is less than the refractive index of the base portion  420  and one surface of the base portion  420  parallel to the base of the pattern portion  410  and the pattern portion  410  form the predetermined angle θ 1 . 
     As light generated at the inside of the filter is effectively emitted to the outside and light entered from the outside of the filter is absorbed, contrast of an image displayed on the plasma display panel is improved. 
     To more effectively absorb light entered from the outside of the filter and to more effectively emit light generated at the inside of the filter, the refractive index of the pattern portion  410  is 0.8 to 0.999 times the refractive index of the base portion  420 . 
     An upper area of the pattern portion is farther from the plasma display panel than a bottom area of the pattern portion. The width (hereinafter, referred to an upper width) of the pattern portion  410  in the upper area is less than the width (hereinafter, referred to a lower width t 1 ) of the pattern portion  410  in the bottom area. The upper width and the lower width t 1  of the pattern portion  410  are set to sufficiently secure the block efficiency of light entered from the outside of the filter and the reflection efficiency of light generated at the inside of the filter. 
     For example, as illustrated in  FIG. 5   b , when the lower width t 1  of the pattern portion  410  is set to 23.0 μm and the upper width of the pattern portion  410  is equal to or less than 23.0 μm, an aperture ratio that is equal to or more than 50% is secured. When the upper width of the pattern portion  410  is equal to or less than 8.0 μm, the block efficiency of light entered from the outside of the filter is reduced. When the height of the pattern portion  410  is t 2 , the upper width of the pattern portion  410  corresponds to half (t 2 /2) the height t 2  of the pattern portion  410 . 
     When the lower width t 1  of the pattern portion  410  range from 1 to 3.5 times the upper width, it is advantageous to block external light and to secure the aperture ratio. 
     The lower width t 1  of the pattern portion  410  may be less than the closest distance between the first electrode  202  and the second electrode  203  (refer to  FIG. 2   a ). In this case, the block efficiency of light entered from the outside of the filter and the reflection efficiency of light generated at the inside of the filter increase. 
     The lower width t 1  of the pattern portion  410  may depend on the width of each of the first electrode  202  and the second electrode  203 . For example, as illustrated in  FIG. 5   c , when a ratio of the lower width t 1  of the pattern portion  410  to the width of the bus electrodes  202   b  or  203   b  (refer to  FIG. 2   b ) ranges from 0.2 to 0.5, an interference fringe (i.e., Moire fringe) generated when two or more periodic patterns overlap is prevented and the external light is blocked efficiently. 
     A ratio of a height t 3  of the base portion  420  to the height t 2  of the pattern portion  410  is set to block the external light and to prevent the dielectric breakdown. 
     For example, as illustrated in  FIG. 5   d , when the height t 3  of the base portion  420  is set to 120 μm and the height t 2  of the pattern portion  410  is equal to or more than 120 μm, the thickness of the base portion  420  decreases. As a result, it is a great likelihood of dielectric breakdown of the pattern portion  410  such that a defective proportion of a filter may increase. When the height t 2  of the pattern portion  410  is equal to or less than 50 μm, light incident on the pattern portion  410  at a predetermined angle is not blocked such that the block efficiency of the external light decreases. 
     Accordingly, it is preferable that the height t 3  of the base portion  420  ranges from 1.01 to 2.25 times the height t 2  of the pattern portion  410 . 
     A ratio of the lower width t 1  of the pattern portion  410  to the width of the barrier rib is set to prevent Moire fringe and to sufficiently secure the block efficiency of the external light. 
     For example, as illustrated in  FIG. 5   e , when a ratio of the lower width t 1  of the pattern portion  410  to the width of the second barrier rib  212   a  (refer to  FIG. 2   a ) ranges from 0.3 to 0.8, the formation of Moire fringe is prevented and the external light is efficiently blocked. 
     Furthermore, the shortest gap t 4  between the pattern portions  410  ranges from 1.1 to 5 times the lower width t 1  of the pattern portion  410 . Accordingly, an aperture ratio of the filter is sufficiently secured, light entered from the outside of the filter is sufficiently blocked, and manufacturing processes of the pattern portion  410  are easily performed. 
     Furthermore, the longest gap t 5  between the pattern portions  410  ranges from 1.1 to 3.25 times the shortest gap t 4  between the pattern portions  410 . Accordingly, the aperture ratio of the filter is sufficiently secured, and the angle θ 1  of the pattern portion  410  is set to an ideal value such that light entered from the outside of the filter is sufficiently blocked. 
     Furthermore, the height t 2  of the pattern portion  410  ranges from 0.89 to 4.25 times the shortest gap t 4  between the pattern portions  410 . Accordingly, the aperture ratio of the filter is sufficiently secured, and light entered from the outside of the filter is sufficiently blocked. 
     For example, the lower width t 1  of the pattern portion  410  ranges from 18 μm to 35 μm. 
     The height t 2  of the pattern portion  410  ranges from 80 μm to 170 μm. 
     The height t 3  of the base portion  420  ranges from 100 μm to 180 μm. 
     The shortest gap t 4  between the pattern portions  410  ranges from 40 μm to 90 μm. 
     The longest gap t 5  between the pattern portions  410  ranges from 90 μm to 130 μm. 
       FIGS. 6   a  to  6   e  illustrate other forms of pattern portions. 
     Referring to  FIG. 6   a , a pattern portion  610  includes two portions each having a different width. For example, the pattern portion  610  has a first width at a point “a”, and has a second width at a point “b” above the point “a”. In other words, the width of the pattern portion  610  decreases with a first ratio up to the point “a”, and decreases with a second ratio, that is more than the first ratio, from the point “a” to the point “b”. 
     Referring to  FIG. 6   b , unlike  FIG. 6   a , the width of a pattern portion  630  decreases with a first ratio up to a point “a”, and decreases with a second ratio, that is less than the first ratio, from the point “a” to a point “b”. 
     Referring to  FIG. 6   c , a tip of a pattern portion  650  has a substantially flat form. 
     Referring to  FIG. 6   d , a side surface of the pattern portion  640  forms a smooth curved line. 
     Referring to  FIG. 6   e , a side surface of the pattern portion  660  is a substantially straight line form up to a point “a” and is a curved line form from the point “a” to a point “b”. 
     As described above, a form of the pattern portion may be variously changed. 
       FIGS. 7   a  and  7   b  illustrate a traveling direction of a pattern portion. 
     Referring to  FIG. 7   a , a traveling direction of a pattern portion  700  and a long side of a base portion  710  are substantially parallel to each other. 
     Referring to  FIG. 7   b , a traveling direction of a pattern portion  720  and a long side of the base portion  710  form a predetermined angle θ 2 . 
     As above, when the traveling direction of the pattern portion  720  and the long side of the base portion  710  form the predetermined angle θ 2 , the generation of Moire fringe is efficiently prevented. 
     Furthermore, to more effectively prevent Moire fringe, the predetermined angle θ 2  may range from 0.5° to 9° or from 0.5° to 4.5°. 
     While a stripe type of the pattern portion has been described above, a type of the pattern portion may be variously changed. 
       FIGS. 8   a  to  8   c  illustrate various types of pattern portions. 
     Referring to  FIG. 8   a , a pattern portion  800  is formed in a matrix type. 
     Referring to  FIG. 8   b , a pattern portion  820  is formed in a wave type. 
     Referring to  FIG. 8   c , a pattern portion  830  is formed in a protrusion type. For example, the plurality of the pattern portions  830  of a protrusion type having a hemisphere shape are spaced with a predetermined distance therebetween. 
     As described above, a type of the pattern portion may be variously changed. 
       FIG. 9  illustrates one example of a case of using two or more pattern portions each having a different pattern. 
     Referring to  FIG. 9 , a first sheet  900  and a second sheet  910  may be included in one filter. The first sheet  900  includes a first base portion  902  and a first pattern portion  901  parallel to a long side of the first base portion  902 . The second sheet  910  includes a second base portion  912  and a second pattern portion  911  parallel to a short side of the second base portion  912 . 
     As above, when two or more pattern portions each having a different pattern are used together, a viewing angle of the plasma display panel is be variously controlled. 
       FIG. 10  illustrates another structure of a pattern portion. 
     Referring to  FIG. 10 , a pattern portion  1010  has a plurality of layers. For example, the pattern portion  1010  includes an upper pattern portion  1011  and a lower pattern portion  1012 . The upper pattern portion  1011  covers the lower pattern portion  1012 . 
     A refractive index of the upper pattern portion  1011  may be less than a refractive index of a base portion  1020 . A color of the upper pattern portion  1011  may be darker than a color of the base portion  1020 . 
     A refractive index of the lower pattern portion  1012  may be different from or equal to the refractive index of the upper pattern portion  1011 . For example, the refractive index of the lower pattern portion  1012  is less than the refractive index of the upper pattern portion  1011 . 
       FIGS. 11   a  and  11   b  illustrate an application example of a filter including a pattern portion. 
     Referring to  FIG. 11   a , a first adhesive layer  1180  is formed on the front surface of a plasma display panel  1170 , and a filter  1190  is adhered to the first adhesive layer  1180 . For example, the filter  1190  is adhered to the front surface of the plasma display panel  1170  using a method such as laminating. The filter  1190  is a film type. 
     A reference numeral  1110  indicates a pattern portion,  1120  a base portion,  1130  a substrate, and  1140  an electromagnetic interference (EMI) shielding layer. When the filter is a film type, the substrate  1130  may be made of resin. 
     Furthermore, in the filter  1190 , a second adhesive layer  1150  is formed between the base portion  1120  and the substrate  1130 . A third adhesive layer  1160  is formed between the substrate  1130  and the EMI shielding layer  1140 . 
     In a case where the first adhesive layer  1180  for adhering the filter  1190  and the plasma display panel  1170  is excessively thick, the emission of light generated in the plasma display panel  1170  to the outside may be prevented. Further, in a case where the first adhesive layer  1180  is excessively thin, an adhesive strength between the plasma display panel  1170  and the filter  1190  may be reduced. 
     Accordingly, the thickness of the first adhesive layer  1180  may range from about 10 μm to 50 μm or from about 20 μm to 40 μm. 
     Referring to  FIG. 11   b , the filter  1190  is spaced from the plasma display panel  1170  by a predetermined distance d. For example, the filter  1190  is supported by a supporter  1100  to be spaced from the plasma display panel  1170  by the predetermined distance d. In this case, the filter  1190  may be a glass type. When the filter  1190  is a glass type, the substrate  1130  may made of glass. 
       FIGS. 12   a  and  12   b  illustrate a xenon (Xe) content based on total weight of a discharge gas and a pressure of the discharge gas. 
     A discharge gas filled in the plasma display panel may contain xenon (Xe) equal to or more than 10% based on total weight of the discharge gas in a case of using a pattern portion which is described in one embodiment. A Xe content in the case of using the pattern portion may range from 13% to 30% based on total weight of the discharge gas. 
     More specifically, the above-described pattern portion absorbs light entered from the outside of the plasma display panel and emits light generated inside the plasma display panel to the outside of the plasma display panel, thereby improving a contrast characteristic. However, the pattern portion absorbs a portion of light generated inside the plasma display panel such that the whole luminance may be reduced. 
     To compensate a reduction in the luminance, the discharge gas filled in the plasma display panel contains Xe equal to or more than 10% based on total weight of the discharge gas. 
     More specifically, Xe increases the generation of ultra ultraviolet rays when generating a discharge in the plasma display panel. Therefore, as the Xe content in the discharge gas increases, the quantity of light generated in the discharge cell increases. This results in an increase in the luminance of an image displayed on the plasma display panel. 
     Accordingly, a reduction in the luminance caused by applying the pattern portion to the filter is compensated by setting the Xe content to be equal to or more than 10% based on total weight of the discharge gas. 
     Further, the Xe content in the case of using the pattern portion may range from 13% to 30% based on total weight of the discharge gas. 
       FIG. 12   a  is a graph illustrating changes in a sustain luminance of a sustain signal when the Xe content changes within the range of 2-50% based on total weight of the discharge gas in a case of using the pattern portion. 
     When the Xe content changes within the range of 2-8% based on total weight of the discharge gas in a case of using the pattern portion, the sustain luminance ranges from 560 to 655. On the other hand, when the Xe content is 10% based on total weight of the discharge gas, the sustain luminance increases to 790. In other words, a reduction in the luminance caused by the pattern portion is fully compensated by setting the Xe content to be equal to or more than 10% based on total weight of the discharge gas. 
     When the Xe content is 13% based on total weight of the discharge gas, the sustain luminance increases by about 135 from the sustain luminance obtained when the Xe content is 10%. When the Xe content is 30% based on total weight of the discharge gas, the sustain luminance constantly increases to 1190. When the Xe content is over 30% based on total weight of the discharge gas, the sustain luminance is saturated to 1200. In other words, a reduction in the luminance caused by the pattern portion is fully compensated by setting the Xe content to 13-30% based on total weight of the discharge gas. 
     Referring to  FIG. 12   b , a pressure of a discharge gas filled in the discharge cell may be equal to or less than 500 torr or may be equal to or less than 450 torr. 
     More specifically, as a Xe content in the discharge gas increases, a driving voltage may increase. 
     For example, when the Xe content is 2% based on total weight of the discharge gas, a firing voltage is 150V and it is assumed that the quantity of light generated by one driving signal is quantitatively equal to 100. 
     When the Xe content is 10% based on total weight of the discharge gas, the firing voltage is 250V and the quantity of light generated by one driving signal is quantitatively equal to 150. 
     In other words, as the Xe content increases, the quantity of light increases such that luminance increases. However, the firing voltage further increases. 
     To compensate an increase in the firing voltage, a gas pressure inside the discharge cell may be equal to or less than 500 torr. As above, by setting the gas pressure inside the discharge cell to be equal to or less than 500 torr, a movement of wall charges inside the discharge cell is activated such that the firing voltage decreases. Further, a gas pressure inside the discharge cell may be equal to or less than 450 torr. 
       FIG. 12   b  is a graph illustrating a change in sustain driving voltages when a pressure of a discharge gas changes within the range of 350-600 torr while the Xe content is about 15% based on total weight of the discharge gas. 
     When the pressure of the discharge gas changes within the range of 550-600 torr, a sustain driving voltage ranges from 191V to 194V. On the other hand, when the pressure of the discharge gas is 500 torr, the sustain driving voltage decreases to 183V. In other words, when the pressure of the discharge gas is equal to or less than 500 torr, the sufficiently low sustain driving voltage is obtained even if the Xe content is equal to or more than 10% based on total weight of the discharge gas. 
     When the pressure of the discharge gas is 450 torr, the sustain driving voltage decreases to 178V. In other words, as the pressure of the discharge gas is reduced, the sustain driving voltage gradually falls. When the pressure of the discharge gas is equal to or more than 450 torr, the sustain driving voltage falls more efficiently. 
     The plasma display apparatus according to one embodiment may further include a driver supplying a driving signal to the electrodes of the plasma display panel. The following is a detailed description of the driver, with reference to  FIG. 13 . 
       FIG. 13  illustrates one example of a configuration of the plasma display apparatus according to one embodiment including a driver. 
     Referring to  FIG. 13 , the plasma display apparatus according to one embodiment includes a plasma display panel  1200  and a driver  1210 . 
     Since the plasma display panel  1200  was described in detail with reference to  FIGS. 2   a  and  2   b , a description thereof is omitted. 
     The driver  1210  supplies a driving signal to a first electrode Y or a second electrode Z formed in the plasma display panel  1200 . For example, the driver  1210  supplies a falling signal with a gradually falling voltage to the first electrode Y and a pre-sustain signal to the second electrode Z during a pre-reset period prior to a reset period of at least one of a plurality of subfields of a frame. A polarity direction of the falling signal is opposite to a polarity direction of the pre-sustain signal. 
     Although  FIG. 13  has illustrated a case where the driver  1210  is formed in the form of a signal board, the driver  1210  may be formed in the form of a plurality of boards depending on the electrodes formed in the plasma display panel  1200 . 
     For example, in a case where the first electrode Y and the second electrode Z are formed in parallel to each other and a third electrode X is formed to intersect the first and second electrodes in the plasma display panel  1200 , the driver  1210  may include a first driver supplying a driving signal to the first electrode Y, a second driver supplying a driving signal to the second electrode Z, and a third driver supplying a driving signal to the third electrode X. 
     The driver  1210  will be described in detail below. 
       FIG. 14  illustrates a frame for achieving a gray level of an image displayed by the plasma display apparatus according to one embodiment. 
       FIG. 15  illustrates one example of an operation of the plasma display apparatus according to one embodiment. 
     Referring to  FIG. 14 , a frame for achieving a gray level of an image displayed by the plasma display apparatus according to one embodiment is divided into several subfields each having a different number of emission times. 
     Each subfield is subdivided into a reset period for initializing all the cells, an address period for selecting cells to be discharged, and a sustain period for representing gray level in accordance with the number of discharges. 
     For example, if an image with 256-level gray level is to be displayed, a frame, as illustrated in  FIG. 14 , is divided into 8 subfields SF 1  to SF 8 . Each of the 8 subfields SF 1  to SF 8  is subdivided into a reset period, an address period, and a sustain period. 
     The number of sustain signals supplied during the sustain period determines gray level weight in each of the subfields. For example, in such a method of setting gray level weight of a first subfield to 2 0  and gray level weight of a second subfield to 2 1 , the sustain period increases in a ratio of 2 n  (where, n=0, 1, 2, 3, 4, 5, 6, 7) in each of the subfields. Since the sustain period varies from one subfield to the next subfield, a specific gray level is achieved by controlling the sustain period which are to be used for discharging each of the selected cells, i.e., the number of sustain discharges that are realized in each of the discharge cells. 
     The plasma display apparatus according to one embodiment uses a plurality of frames to display an image during 1 second. For example, 60 frames are used to display an image during 1 second. In this case, a duration T of time of one frame may be 1/60 seconds, i.e., 16.67 ms. 
     Although  FIG. 14  has illustrated and described a case where one frame includes 8 subfields, the number of subfields constituting one frame may vary. For example, one frame may include 12 subfields or 10 subfields. 
     Further, although  FIG. 14  has illustrated and described the subfields arranged in increasing order of gray level weight, the subfields may be arranged in decreasing order of gray level weight, or the subfields may be arranged regardless of gray level weight. 
       FIG. 15  illustrates one example of an operation of the plasma display apparatus according to one embodiment in one subfield of a plurality of subfields of one frame as illustrated in  FIG. 14 . 
     During a pre-reset period prior to a reset period, the driver  1210  of  FIG. 13  supplies a falling signal with a gradually falling voltage (i.e., a first falling signal) to a first electrode Y. 
     During the supplying of the first falling signal to the first electrode Y, the driver  1210  supplies a pre-sustain signal of a polarity direction opposite a polarity direction of the first falling signal to a second electrode Z. 
     The first falling signal supplied to the first electrode Y gradually falls from a ground level voltage GND to a tenth voltage V 10 . 
     The pre-sustain signal is constantly maintained at a pre-sustain voltage Vpz. The pre-sustain voltage Vpz is substantially equal to a voltage (i.e., a sustain voltage Vs) of a sustain signal (SUS) which will be supplied during a sustain period. 
     As above, during the pre-reset period, the first falling signal is supplied to the first electrode Y and the pre-sustain signal is supplied to the second electrode Z. As a result, wall charges of a predetermined polarity are accumulated on the first electrode Y, and wall charges of a polarity opposite the polarity of the wall charges accumulated on the first electrode Y are accumulated on the second electrode Z. For example, wall charges of a positive polarity are accumulated on the first electrode Y, and wall charges of a negative polarity are accumulated on the second electrode Z. 
     As a result, a setup discharge with a sufficient strength occurs during the reset period such that the initialization of all the discharge cells is performed stably. 
     Even if the amount of wall charges accumulated inside the discharge cell is not sufficient, a setup discharge with a sufficient strength occurs. 
     Furthermore, although a voltage of a rising signal supplied to the first electrode Y during the reset period is low, a setup discharge with a sufficient strength occurs. 
     A subfield, which is first arranged in time order in a plurality of subfields of one frame, may include a pre-reset period prior to a reset period so as to obtain sufficient driving time. Or, two or three subfields may include a pre-reset period prior to a reset period. 
     All the subfields may not include the pre-reset period. 
     The reset period is further divided into a setup period and a set-down period. During the setup period, the driver  1210  supplies the rising signal of a polarity direction opposite a polarity direction of the first falling signal to the first electrode Y. 
     The rising signal includes a first rising signal and a second rising signal. The first rising signal gradually rises from a twentieth voltage V 20  to a thirtieth voltage V 30  with a first slope, and the second rising signal gradually rises from the thirtieth voltage V 30  to a fortieth voltage V 40  with a second slope. 
     The rising signal generates a weak dark discharge (i.e., a setup discharge) inside the discharge cell during the setup period, thereby accumulating a proper amount of wall charges inside the discharge cell. 
     The second slope of the second rising signal is gentler than the first slope of the first rising signal. When the second slope is gentler than the first slope, the voltage of the rising signal rises relatively rapidly until the setup discharge occurs, and the voltage of the rising signal rises relatively slowly during the generation of the setup discharge. As a result, the quantity of light generated by the setup discharge is reduced. Accordingly, contrast of the plasma display apparatus is improved. 
     During the set-down period, the driver  1210  supplies a second falling signal of a polarity direction opposite a polarity direction of the rising signal to the first electrode Y. The second falling signal gradually falls from the twentieth voltage V 20  to a fiftieth voltage V 50 . The second falling signal generates a weak erase discharge (i.e., a set-down discharge) inside the discharge cell. Furthermore, the remaining wall charges are uniform inside the discharge cells to the extent that an address discharge can be stably performed. 
     The following is a detailed description of another form of a rising signal and a second falling signal, with reference to  FIGS. 16   a  and  16   b.    
       FIGS. 16   a  and  16   b  illustrate another form of a rising signal and a second falling signal. 
     Referring to  FIG. 16   a , the rising signal sharply rises to the thirtieth voltage V 30 , and then gradually rises from the thirtieth voltage V 30  to the fortieth voltage V 40 . 
     The rising signal illustrated in  FIG. 15  may gradually rise with the two different slopes through two stages. However, the rising signal illustrated in  FIG. 16   a  may gradually rise through one stage. As above, the rising signal may vary in the various forms. 
     Referring to  FIG. 16   b , the second falling signal gradually falls from the thirtieth voltage V 30 . As above, a voltage falling time point of the second falling signal is changeable. In other words, the second falling signal may vary in the various forms. 
     Referring again to  FIG. 15 , during the address period, the driver  1210  supplies a scan bias signal, which is maintained at a voltage higher than the fiftieth voltage V 50  of the second falling signal, to the first electrode Y. 
     A scan signal (Scan), which falls from the scan bias signal by a scan voltage magnitude ΔVy, is supplied to all the first electrodes Y 1  to Yn. 
     For example, a first scan signal (Scan  1 ) is supplied to the first electrode Y 1 , and then a second scan signal (Scan  2 ) is supplied to the first electrode Y 2 . Therefore, an n-th scan signal (Scan n) is supplied to the first electrode Yn. 
     The width of the scan signal may vary from one subfield to the next subfield. In other words, the width of a scan signal in at least one subfield may be different from the width of a scan signal in the other subfields. For example, the width of a scan signal in a subfield may be more than the width of a scan signal in the next subfield in time order. Further, the width of the scan signal may be gradually reduced in the order of 2.6 μs, 2.3 μs, 2.1 μs, 1.9 μs, etc., or in the order of 2.6 μs, 2.3 μs, 2.3 μs, 2.1 μs, 1.9 μs, 1.9 μs, etc. 
     As above, when the scan signal (Scan) is supplied to the first electrode Y, a data signal (data) corresponding to the scan signal (Scan) is supplied to the third electrode X. The data signal (data) rises from a ground level voltage GND by a data voltage magnitude ΔVd. 
     As the voltage difference between the scan signal (Scan) and the data signal (data) is added to the wall voltage generated during the reset period, the address discharge is generated within the discharge cell to which the data signal (data) is supplied. 
     A proper amount of wall charges remains to extent that a sustain discharge occurs when the sustain signal (SUS) is supplied inside the discharge cell selected by performing the address discharge. 
     A sustain bias signal is supplied to the second electrode Z during the address period to prevent the generation of the unstable address discharge by interference of the second electrode Z. The sustain bias signal is substantially maintained at a sustain bias voltage Vz. The sustain bias voltage Vz is lower than the voltage Vs of the sustain signal and is higher than the ground level voltage GND. 
     During the sustain period, a sustain signal (SUS) is alternately supplied to the first electrode Y and the second electrode Z. The sustain signal (SUS) has a voltage magnitude corresponding to the sustain voltage Vs. 
     As the wall voltage within the discharge cell selected by performing the address discharge is added to the sustain voltage Vs of the sustain signal (SUS), every time the sustain signal (SUS) is supplied, the sustain discharge, i.e., a display discharge occurs between the first electrode Y and the second electrode Z. Accordingly, a predetermined image is displayed on the plasma display panel. 
       FIG. 17  illustrates another type of a sustain signal. 
     Referring to  FIG. 17 , a sustain signal ((+)SUS 1 , (+)SUS 2 ) of a positive polarity direction and a sustain signal ((−)SUS 1 , (−)SUS 2 ) of a negative polarity direction are alternately supplied to either the first electrode Y or the second electrode Z, for example, to the first electrode Y in  FIG. 17 . 
     As above, when the sustain signal of the positive polarity direction and the sustain signal of the negative polarity direction are alternately supplied to the first electrode Y, a bias signal is supplied to the second electrode Z. The bias signal is constantly maintained at the ground level voltage GND. 
     As above, the sustain signal may vary in various forms. 
     Further, when the sustain signal (SUS) is supplied to either the first electrode Y or the second electrode and the bias signal is supplied to the other electrode during the sustain period, the configuration of the driver is simplified. 
     As illustrated in  FIG. 17 , when the sustain signal is supplied to either the first electrode Y or the second electrode Z, a single diving board for installing a circuit for supplying the sustain signal (SUS) to either the first electrode Y or the second electrode Z is required. Accordingly, the whole size of the driver is reduced such that the manufacturing cost is reduced. 
     The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present invention. The present teaching can be readily applied to other types of apparatuses. The description of the foregoing embodiments is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Moreover, unless the term “means” is explicitly recited in a limitation of the claims, such limitation is not intended to be interpreted under 35 USC 112(6).