Abstract:
A front panel structure of Plasma Display Panel (PDP) is disclosed sequentially comprising a first electrode, a second electrode and a third electrode, wherein the second electrode has transparent electrodes located on both top and bottom sides of a bus electrode. A first discharge center is formed between a transparent electrode of the first electrode and one transparent electrode of the second electrode. A second discharge center is formed between the other transparent electrode of the second electrode and a transparent electrode of the third electrode. Therefore, an emitting cell of PDP has two discharge centers. To make the discharge more stable, we choose the first electrode and the third electrode to become the scan electrodes, or to form a thicker dielectric layer or discharge deactivation film below the second bus electrode as a scan electrode.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a plasma display panel (PDP), and more particularly, to a front panel structure of the PDP.  
       BACKGROUND OF THE INVENTION  
       [0002]     Since multi-media are rapidly developed, the standard of users&#39; requirements for peripheral audio and video devices is getting higher and higher. Because of the oversized volume, CRT(Cathode Ray Tube)-type display devices used to be popular can no longer meet the requirements in the current age of focusing on lightness, thinness, shortness and smallness. Hence, many technologies regarding flat panel displays have been developed subsequently, such as a liquid crystal display (LCD), a PDP and a field emission display (FED), which have been gradually become the mainstream of future display devices, wherein the PDP used as a full-color display device has received great attention due to its large display area, particularly for the application on big-sized TVs or outdoor bulletins. The reasons why the PDP is so popular are that: the PDP has the display capability of high image quality, which is resulted from the light-emitting style of wide view angle and the high-speed response. Further, the process for manufacturing the PDP is relatively simple and suitable for use in big-sized display devices.  
         [0003]     In a color PDP, gas discharge is used to generate ultraviolet (LTV) ray to excite phosphors to emit visible light, thereby achieving the display effect. According the discharge mode of the PDP, the color PDP can be briefly divided into an AC type and a DC type. In an AC-typed PDP, there is a passivation layer covering an electrode, so that the AC-typed PDP has relatively long operation life and relatively high display brightness. Hence, with regard to the display effect, the luminance efficiency and the operation life, the AC-typed PDP is generally superior to a DC-typed PDP.  
         [0004]     Generally, the structure of three electrodes is used in the AC-typed PDP, including a common electrode, a scan electrode and an address electrode.  FIG. 1  is a schematic top view showing the front panel structure of a general PDP. Referring to  FIG. 1 , the front panel structure is mostly formed in a top substrate located on one side of the image display, including an electrode  10  and an electrode  12  which are opposite to each other in structure, wherein one of the electrodes is a scan electrode and the other is a common electrode. Both of the electrode  10  and the electrode  12  are composed of a transparent electrode  14  and a bus electrode  16 , wherein the transparent electrode  14  is generally made of transparent electrode material, such as indium tin oxide (ITO; a mixture of indium oxide and tin oxide), used for allowing visible light to pass through. Also, in comparison with metal, the transparent electrode  14  has lower electrical conductivity, and thus the bus electrode  16  which is narrow and has excellent electrical conductivity has to be added to the transparent electrode  14 , so as to increase the overall electrical conductivity, wherein the bus electrode  16  can be made of the material such as black silver or white silver.  
         [0005]     An emitting cell  20  is a division formed by using separation walls  24  in the structure of bottom substrate, wherein the area enclosed by the separation walls  24  forms the emitting cell  20 , such as the square area enclosed by dashed lines shown in  FIG. 1 . Further, the bus electrode  16  crosses over each of the emitting cells  20  arranged in a row, and is connected to a signal-supplying device (not shown), thereby controlling the gas discharge of a specific emitting cell. A discharge center  22  of each emitting center  20  is located between two transparent electrodes  14 , such as the circular area enclosed by dashed lines shown in  FIG. 1 . In the area between the emitting cells  20  of different rows, a black-line structure  18  is generally formed for blocking the light therebelow.  
         [0006]     When a voltage is applied to the specific cell, the potential between electrodes will form an electric field, thereby accelerating the charged particles of the gas mixture sealed in the emitting cell, and the charged particles also collide with neutral particles so as form more electrons and ions for generating vacuum ultraviolet (VUV) light. Then, the VUV light is used to excite phosphors existing in the emitting cell, so as to enable the phosphors of three colors, red (R); green (G); and blue (B), to generate visible light for further displaying an image.  
       SUMMARY OF THE INVENTION  
       [0007]     In the structural design of the electrodes in the top substrate of the conventional PDP, each of the emitting cells has only one discharge center. Hence, when the PDP is performing a discharge step, the electric field intensity is the maximum at the central position in the emitting cell, and thus sever discharge occurs at the center of the emitting cell. Since the sever discharge is concentrated in the neighborhood of the discharge center, the conventional PDP has lower discharge efficiency and short operation life. Further, in the conventional front panel structure, the area of the transparent electrode is too large, thus causing overlarge peak current generated during discharge, so that not only the load of the circuit elements is increased, but also the production life and the operational voltage range of the panel are affected.  
         [0008]     Hence, one object of the present invention is to provide a front panel structure of a PDP, each of the emitting cells having at least two discharge centers, used for providing relatively uniform discharge current and area.  
         [0009]     Hence, the other object of the present invention is to provide a PDP applied to the aforementioned front panel structure of dual discharge centers, for improving the operation life of the panel.  
         [0010]     According the objects of the present invention, a front panel structure of the present invention comprises: a first electrode; a third electrode and a second electrode located between the first electrode and the third electrode, wherein the first electrode is composed of a bus electrode and a transparent electrode located on one side of the bus electrode; the second electrode is composed of a bus electrode and two transparent electrodes located on the top and bottom sides of the bus electrode; and the third electrode is composed of a bus electrode and a transparent electrode located on one side of the bus electrode. Also, the transparent electrode of the first electrode is opposite to one transparent electrode of the second electrode so as to form one discharge center, and the transparent electrode of the third electrode is opposite to the other transparent electrode of the second electrode so as to form the other discharge center.  
         [0011]     According to the objects of the present invention, a PDP of the present invention comprises: a first substrate and a second substrate; a plurality of address electrodes located between the first substrate and the second substrate; a plurality of emitting rows located between the first substrate and the address electrodes, wherein each of the emitting rows comprises a first electrode, a third electrode and at least one second electrode located between the first electrode and the third electrode; and a plurality of separation walls located between the emitting rows and the address electrodes, wherein the separation walls are arranged alternatively with the address electrodes, so as to divide the emitting rows into a plurality of emitting cells, each emitting cell having a first discharge center located between the first electrode and the second electrode, and a second discharge center located between the second electrode and the third electrode.  
         [0012]     In a preferred embodiment of the present invention, the electrode parts can be varied. For example, the first electrode can be optionally connected to the same signal-supplying device with the third electrode, and consequently the first electrode and the third electrode become branches of the same electrode. Meanwhile, the first electrode and the third electrode can be optionally used as scan electrodes, and the second electrode can be optionally used as a common electrode; or the first electrode and the third electrode can be optionally used as common electrodes, and the second electrode can be optionally used as a scan electrode.  
         [0013]     Further, the bus electrodes and the transparent electrodes can be designed alternatively. For example, the aforementioned bus electrode can be optionally formed as in the shape of comb, having a main line and several branch lines. The transparent electrode can be coupled to the branches lines of the bus electrode, and can be designed in the shape of long line or frame stripe, or has a certain distance away from the main line of the bus electrode. Further, a hollow space may exist in the middle of the bus electrode of the second electrode, such as a hollow space which is long-fine-stripe shape and is parallel to the bus electrode of the second electrode.  
         [0014]     On the other hand, the present invention can also make the distance between the transparent electrode of the first electrode and the transparent electrode of the second electrode different from that between the transparent electrode of the second electrode and the transparent electrode of the third electrode, thereby making the discharge gaps of two discharge centers different. Also, a black-line structure can be inserted between two emitting rows for blocking light.  
         [0015]     The application of the front panel structure according to the present invention can provide the advantages of providing uniform discharge, promoting discharge efficiency, increasing luminance intensity, prolonging the operation life of the product, broadening operational voltage range, balancing firing voltage and efficiency, and distributing peak current, etc. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:  
         [0017]      FIG. 1  is a schematic top view showing the front panel structure of a general PDP;  
         [0018]      FIG. 2  is a schematic top view showing the front panel structure of dual discharge centers, according to the present invention;  
         [0019]      FIG. 3  is a schematic top view showing the front panel structure of a PDP, according to a preferred embodiment of the present invention;  
         [0020]      FIG. 4  is a schematic top view showing a bus electrode of the electrode shown in  FIG. 3 ;  
         [0021]      FIG. 5  is a schematic top view showing a bus electrode of the other electrode shown, according to the preferred embodiment of the present invention;  
         [0022]      FIG. 6  is a schematic top view showing the front panel structure of a PDP, according to another preferred embodiment of the present invention;  
         [0023]      FIG. 7  is a schematic top view showing the front panel structure of a PDP, according to another preferred embodiment of the present invention;  
         [0024]      FIG. 8  is a 3-D schematic perspective diagram showing a PDP having a front panel structure of the present invention.  
         [0025]      FIG. 9  is a cross-section showing the front panel structure of a PDP according to another preferred embodiment of the present invention; and  
         [0026]      FIG. 10  is a cross-section showing the front panel structure of a PDP according to still another preferred embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0027]     In the following, several preferred embodiments are used for explaining the PDP front panel structure of the present invention. In order to make the description regarding the present invention more complete and in detail, please refer to the following description about the preferred embodiments accompanying with FIGS.  2  to  7 .  
         [0028]     The present invention provides a front panel structure having dual discharge centers, forming two discharge centers in each of the emitting cells, wherein a bus electrode of a common electrode is located in the center of an emitting cell, and transparent electrodes are formed on both sides of the bus electrode of the common electrode. A bus electrode of a scan electrode is located on both top and bottom sides of the emitting center, and can be controlled by the same signal-supplying device or different signal-supplying devices, and a transparent electrode is formed on the inner side of the bus electrode of the scan electrode, i.e. the location near the center of the emitting cell, thereby forming two discharge centers in the same emitting cell. The positions of the above-described common and scan electrodes can be swapped, i.e. the scan electrode is located in the center of the emitting cell; and the common electrodes are located on both top and bottom sides thereof.  
         [0029]      FIG. 2  is a schematic top view showing the front panel structure of dual discharge centers, according to the present invention. Referring to  FIG. 2  the front panel structure are mostly formed on a top substrate located on one side of a display image, including electrodes  100 ,  102  and  104  which are spaced apart from one another with a certain distance., wherein the electrode  100  and the electrode  104  belong to the same type of electrode. For example, if the electrode  100  and the electrode  104  are scan electrodes, the electrode  102  is a common electrode; and if the electrode  100  and the electrode  104  are common electrodes, then the electrode  102  is a scan electrode.  
         [0030]     Regardless of the electrode  100 , the electrode  102  and the electrode  104 , they are all composed of transparent electrodes and bus electrodes mutually connected, wherein the transparent electrodes are made of transparent electrode material, such as ITO, used for allowing visible light to pass through; and the bus electrodes are used for increasing the electrical conductivity of the electrodes, and can be made of the material such as aluminum, cobalt, silver, molybdenum, chromium, tantalum, tungsten, iron, copper or the alloys thereof. Generally speaking, the bus electrode is opaque.  
         [0031]     For example, the electrode  100  is composed a long-striped-shaped transparent electrode  108   a  and a long-striped-shaped bus electrode  110   a;  and the electrode  102  is composed a long-striped-shaped transparent electrode  108   b ′, a long-striped-shaped transparent electrode  108   b ″ and a long-striped-shaped bus electrode  110   b,  wherein the transparent electrode  108   b ′ and the transparent electrode  108 ″ are respectively located on both top and bottom sides of the bus electrode  110   b,  and the transparent electrode  108   b ′ is located on the same side with the transparent electrode  108   a  with no contact. The electrode  104  is also composed a long-striped-shaped transparent electrode  108   c  and a long-striped-shaped bus electrode  110   c,  wherein the transparent electrode  108   c  is located on the same side with the transparent electrode  108   b ″ with no contact. Hence, such as shown in  FIG. 2 , sequentially from the top to the bottom, the repetition structure is composed of: the bus electrode  110   a,  the transparent electrode  108   a,  the transparent electrode  108   b ′, the bus electrode  110   b,  the transparent electrode  108   b ″, the transparent electrode  108   c  and the bus electrode  110   c.    
         [0032]     An emitting row is composed of the electrode  100 , the electrode  102  and the electrode  104 , such as row I, row II and row III. Each of the emitting rows is also divided into several emitting cells  112  by separation walls  106  fabricated on the structure of the bottom substrate, wherein the bus electrode  110   a,  the bus electrode  110   b  and the bus electrode  100   c  cross over each of the emitting cells  112  arranged in a row, and are connected to a signal-supplying device (not shown) for controlling gas discharge of a specific emitting cell. Generally speaking, the signal-supplying device of the scan electrode is different from that of the common electrode, and the bus electrodes  110   a  and  110   c  belonging to the same type of electrode in the aforementioned structure can be optionally connected to the same signal-supplying device. The choice of being connected to the same signal-supplying device means that the electrode  100  and the electrode  104  are branches of the same electrode, and are controlled by the same signal-supplying device.  
         [0033]     The emitting cell  112  thus has two discharge centers, which respectively are a discharge center  114  located between the transparent electrode  108   a  and the transparent electrode  108   b ′; and a discharge center  116  located between the transparent electrode  108   b ″ and the transparent electrode  108   c,  such as the dashed circular areas shown in  FIG. 2 .  
         [0034]     Except that each of the emitting rows can generally be the direct connections of the horizontal straight bus electrodes and the transparent electrodes (such as shown in  FIG. 2 ), each of the bus electrodes can be also designed in the shape of comb, wherein the extended branch lines of the comb-shaped bus electrodes can be used for connecting to the transparent electrodes, such as shown in  FIG. 3 . In order to make the description regarding the bus electrodes clearer, the bus electrodes are depicted alone in  FIG. 4 . Referring to  FIG. 4 , a comb-shaped bus electrode  110   a  comprises a main line  150  which crosses over each of the emitting cells  112  arranged in a row and is connected to a signal-supplying device (not shown); and several branch lines  152  which are extended from one side of the main line  150  and are located between the emitting cells  112 . A comb-shaped bus electrode  110   b  comprises a main line  154  which crosses over each of the emitting cells  112  arranged in a row and is connected to a signal-supplying device (not shown); and several branch lines  156  which are extended from both top and bottom sides of the main line  154  and are located between the emitting cells  112 . A comb-shaped bus electrode  110   c  comprises a main line  158  which crosses over each of the emitting cells  112  arranged in a row and is connected to a signal-supplying device (not shown); and several branch lines  160  which are extended from one side of the main line  158  and are located between the emitting cells  112 . The aforementioned number of branch lines matching the main line can be changed arbitrarily, and the present invention is not limited thereto.  
         [0035]     Thereafter, referring to  FIG. 3  again, when the comb-shaped front panel structures shown in  FIG. 4  are applied to the front panel structure of dual discharge centers, generally, the branch lines of the bus electrode  110   a,  those of the bus electrode  110   b  and those of the bus electrode  110   c  (such as branch lines  152 ,  156  and  160  shown in  FIG. 4 ) are aligned to the separation walls  106 . Hence, the opaque branch lines of the bus electrodes do not block the light emitted from the emitting cells  112 . Further, the transparent electrodes of each electrode can be merely coupled to the branch lines of the comb-shaped bus electrode. For example, the transparent electrode  108   a  of the electrode  100  can be incompletely connected to the bus electrode  110   a  thereof, and is merely coupled to the branch line (such as the branch line  152  shown in  FIG. 4 ) of the bus electrode  110   a.  Hence, in comparison with the structure shown in  FIG. 2 , the area of the transparent electrode  108   a  is reduced a lot. Similarly, the areas of the transparent areas  108   b ′ and  108   b ″ of the electrode  102 , and the area of the transparent electrode  108   c  of the electrode  104  are also reduced a lot accordingly. Since a discharge gap can be defined as the distance between two transparent electrodes, thus in this preferred embodiment, the discharge gap of the discharge center  114  and that of the discharge center  116  both are d 0 . The shapes of the transparent electrodes matching the comb-typed bus electrodes are not merely limited to the fine-line shape having arch edges, and the other shapes such as a long-stripe shape can also be adopted by making modification in accordance with the actual needs, so that the present invention is not limited thereto.  
         [0036]     In the front panel structure of the present invention, the bus electrode located in the center of each emitting row can further have a hollow space, such as shown in  FIG. 5 . Referring to  FIG. 5 , the bus electrode  110   b  penetrates the center of the emitting cell  112 , and the main line  154  thereof is wider than that shown in  FIG. 4 , and several hollow spaces  162  of long-fine-stripe shape parallel to the main line  154  exist therein, wherein the shapes of the hollow spaces  162  can be changed in accordance with the actual needs, and the relative position of the hollow space in the emitting cell  112  or in the front panel structure is not limited and can be moved optionally, so that the present invention is not limited thereto. Further, the hollow space  162  is not necessarily limited to being used together with the bus electrode  110   b  having the main line  164  and the branch lines  156 , but also can be used together with the long-stripe-shaped bus electrode  110   b  as shown in  FIG. 2 , so that the present invention is not limited thereto.  
         [0037]     In the structure shown in  FIG. 2  and  FIG. 3  of the present invention, there is no black-line sure existing between the emitting rows. However, in a preferred embodiment of the present invention, black-line structures can be inserted between the emitting rows, such as shown in  FIG. 6 . Referring to  FIG. 6 , an emitting row I and an emitting row II are divided by a black-line structure  170 , so are the emitting row II and an emitting row III, and thus the light-blocking effect between the emitting rows is even better.  
         [0038]     Further, the present invention can make some amendment on the discharge gap, so as to make those two discharge centers of the discharge cell different, such as shown in  FIG. 7 . Referring to  FIG. 7 , under the condition without changing the original width of the emitting row, the entire electrode  102  can be moved upwards from the original position, so as to shorten the distance between the electrode  100  and the electrode  102 , and increase the distance between the electrode  102  and the electrode  104 . Therefore, in this front panel structure, the discharge gap of the discharge center  114  is d 1 , and the discharge gap of the discharge center  116  is d 2 , wherein d 2 &gt;d 1 . Alternatively, under the condition without changing the original width of the emitting row and the original positions of the bus electrodes, the transparent electrodes of the electrodes can be moved so as to change the widths of the discharge gaps. For example, the transparent electrode  108   b ′ is moved towards the transparent electrode  108   a,  and the transparent electrode  108   b ″ is moved towards the transparent electrode  108   c.  The aforementioned methods for changing the discharge gaps are merely stated as examples for explanation, and the present invention is not limited thereto.  
         [0039]     Further, the size and proportionality of the aforementioned front panel structure, such as the widths of the electrodes  102 ,  100  and  104 ; the discharge gaps; the distance between the transparent electrode and the bus electrode; and the distance between the emitting rows, etc., all can be changed in accordance with the product requirements, and thus the present invention is not limited thereto.  
         [0040]      FIG. 8  is a 3-D schematic perspective diagram showing a PDP having a front panel structure of the present invention. Referring to  FIG. 8 , a PDP comprises a top substrate  200  and a bottom substrate  202 . A plurality of address electrodes  206  arranged in parallel are located on the bottom substrate  202 , and a dielectric layer  212  covers the address electrodes  206 . A plurality of separation walls  106  arranged in parallel are formed on the dielectric layer  212 , and are located between the address electrodes  206  and arranged alternatively with the address electrodes  206 . Certainly, the present invention is not limited to the stripe-shaped separation walls  106  shown in  FIG. 8 , and can be the separation wall structures of various shapes. There is a color phosphor layer  210  between the separation walls  106 . The inner side of the top substrate  200 , i.e. the side in the same direction with the bottom substrate, has the electrode  100 , the electrode  102  and the electrode  104 , wherein the electrode  100  is composed of the bus electrode  110   a  and the transparent electrode  108   a;  the electrode  102  is composed of the bus electrode  110   b,  the transparent electrode  108   b ′ and the transparent electrode  108   b ″; and the electrode  104  is composed of the bus electrode  110   c  and the transparent electrode  108   c,  wherein the transparent electrode  108   a  is opposite to the transparent electrode  108   b ′; and the transparent electrode  108   c  is opposite to the transparent electrode  108   b ″. The aforementioned electrodes  100 ,  102  and  104  form an emitting row. Certainly, the present invention is not limited to having only one emitting row, but can have several emitting rows. Further, a dielectric layer  204  and a protective layer  208  are formed on the top substrate  100  to cover the electrodes  100 ,  102  and  104 . The numerals shown in  FIG. 8  and those shown in  FIG. 1  are the same, representing identical elements, so that  FIG. 1  and  FIG. 8  can be used as cross-references.  
         [0041]      FIGS. 9 and 10  are cross-sections showing the front panel structure of a PDP of the preset invention, wherein the dielectric layer  204  and protective layer  208  are formed on the front panel structure. As described above, there is discharge unstable when optionally uses the second electrode as a scan electrode. Therefore, the dielectric layer  204  under the bus electrode  110   b  of the electrode  102  can make thicker as shown in  FIG. 9 , or a discharge deactivation film  214  can be formed on the protective layer  208  as shown in  FIG. 10 , to avoid the discharge unstable.  
         [0042]     It can be known from the preferred embodiments of the present invention that the front panel structure of the present invention is to divide one original emitting cell into two sub-emitting cells, such as a sub-emitting cell  120  and a sub-emitting cell  122  shown in  FIG. 2 . Thus, the distance of UV light diffused from the discharge center of each sub-emitting cell to the edge of the emitting cell is shorter than that of UV light diffused from the conventional discharge center  22  shown in  FIG. 1  to the edge of the emitting cell, thus preventing the loss of the UV light diffused from the discharge center. Since the present invention can reduce the loss of UV light and make the distribution thereof more uniform, the luminance intensity of the phosphors can be effectively enhanced.  
         [0043]     Moreover, while the front panel structure of the present invention is under gas discharge, the discharge area is allocated on two areas of the emitting cell, so that the discharge is more uniform so as to prevent the shortcoming of being overly emphasized on the central position of the emitting cell and causing the damage of the conventional panel, thus prolonging the operation life of the product.  
         [0044]     In the front panel structure of the present invention, since the dual discharge centers and the comb-shaped electrodes can provide more uniform electric field, even more uniformly distributed light can be obtained accordingly, and since the comb-shaped electrode is much closer to the discharge center than the conventional bus electrode, the operational driving voltage range of the PDP is much broader, thus benefiting for the input of high-speed signals during the phase of driving operation. Further, when the comb-shaped electrode is made of anti-reflection material, the displaying contrast of the PDP can be further enhanced; when the area used by the transparent electrode is less, the power consumption can be reduced while maintaining discharge. Further, if the bus electrode penetrating through the center of the emitting cell has a hollow space, then the allowed current value is increased and the light-blocking area is reduced.  
         [0045]     In the front panel structure of the dual discharge centers according to the present invention, when the sub-emitting centers of one identical emitting center are designed to respectively having different discharge gaps, there are advantages of balancing firing voltage and increasing luminance efficiency, and also due to different discharge time of the two sub-emitting centers, the peak current during discharge can be well distributed.  
         [0046]     Speaking in more detail, the luminance efficiency and firing voltage are proportional to the discharge gap, i.e. the bigger the discharge gap is, the higher the firing voltage is and the better the luminance efficiency is. However, with too large firing voltage, the cost of driving is increased a lot because the driving method of higher voltage is needed. Therefore, referring  FIG. 7 , in the structure of the dual discharge centers having different discharge gaps according to the present invention, since the discharge gap d 2  is larger than the discharge gap d 1 , a lower firing voltage can be used to drive the sub-emitting cell  120  having, and thus active particles are generated and diffused to the sub-emitting cell  122 , so that the sub-emitting cell  122  can be driven even with the driving voltage less than the original firing voltage. Meanwhile, the sub-emitting cell  122  can obtain better luminance efficiency, and the peak current can be distributed and lowered since the discharge of the sub-emitting cell  120  occurs earlier than that of the sub-emitting cell  122 .  
         [0047]     In the dual emitting centers of the present invention, except the aforementioned description of changing the discharge gaps to change the firing voltages of the two sub-emitting cells, the thickness of the electrical inductor can also be changed to change the firing voltages. For example, referring to  FIG. 8 , generally, during a writing period, the address electrode  206  and the scan electrode are controlled to perform a discharge step for enabling one certain emitting cell or sub-emitting cell to generate light, and then in a maintaining period, the scan electrode and the common electrode of the same emitting cell or sub-emitting cell are used to perform a discharge step for maintaining the luminance effect. Hence, assume that the electrode  100  and the electrode  104  are the scan electrodes, and the electrode  102  is the common electrode. In an emitting cell, if thickness of the dielectric layer  204  under the electrodes  100  and  104  used as the scan electrodes is changed, or the thickness of the dielectric layer  212  which corresponds to the electrode  100  and the electrode  104 , and is located above the address electrode  206  is changed, then the firing voltage of the sub-emitting cell located on the position at which the electrode  100  crosses with the address electrode  206  is different from that of the sub-emitting cell located on the position at which the electrode  104  crosses with the address electrode  206 .  
         [0048]     As is understood by a person skilled in the art, the foregoing preferred embodiments of the present invention are illustrated of the present invention rather than limiting of the present invention. It is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, the scope of which should be accorded the broadest interpretation so as to encompass all such modifications and similar structures.