Abstract:
A plasma display panel having scanning electrodes (Y) and sustaining electrodes (X) arranged in the form of XX-YY-XX-YY . . . , a rib structure vertically crossing the scanning electrodes (Y) and sustaining electrodes (X). The priming discharges during reset period does not occur in the display areas of the plasma display panel, the picture quality is assured from avoiding the emission of over-brightness in the reset period which enables the sequential gaseous discharge operations to proceed with smaller driving voltage.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]    This application is a continuation-in-part of U.S. patent application Ser. No. 09/810,360 filed Mar. 16, 2001, which is hereby incorporated by reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention generally relates to a plasma display panel (hereinafter referred to as PDP) and a method of driving the PDP. More specifically, the method and apparatus of the present invention can reduce the back-glow phenomena caused by the discharge operation during the reset period for a PDP, therefore, enhancing the contrast of the plasma display panel  
           [0004]    The present invention generally relates to a plasma display panel (hereinafter referred to as PDP). More specifically, it relates to a plasma panel can reduce the back-glow phenomena caused by the discharge operation during the reset period, therefore, enhancing the contrast of the plasma display panel.  
           [0005]    2. Description of the Related Art  
           [0006]    Plasma display is one of most promising flat panel display technologies because it can provide a large and flat display screen and can display full-color images. The basic theory and operation of a PDP is described below.  
           [0007]    [0007]FIG. 1 is a cross-sectional view of a conventional PDP cell constructed by two glass substrates  1  and  7  and the components formed thereon. Inert gases, such as Ne and Xe, are filled in the cavity between the glass substrates  1  and  7 . The components formed on the glass substrate  1  include sustaining electrodes X, scanning electrodes Yi, a dielectric layer  3  and a protective film  5 . The components formed on the glass substrate  7  include address electrodes Aj and the fluorescent material  9  formed thereon. The rib  8  (generally which is parallel to the scanning electrodes Yi and the sustaining electrodes X) is formed on the peripheral of each PDP cell to isolate the PDP cell. Therefore, each PDP cell  10  includes three kinds of electrodes, i.e., the sustaining electrode X and the scanning electrode Yi, which is parallel to each other, and the address electrodes Aj crossing vertically the sustaining electrode X and the scanning electrode Yi.  
           [0008]    [0008]FIG. 2 is a block diagram illustrating a plasma display formed by the PDP cells shown in FIG. 1. As shown in the drawing, the PDP  100  is driven by the scanning electrodes Y 1 ˜Yn, the sustaining electrodes X and the address electrodes A 1 ˜Ap. The position of the cell  10  is as shown in the drawing. Each cell is isolated by the rib  8  as shown in FIG. 1. Furthermore, the plasma display includes the control circuit  110 , the Y scanning driver  112 , the X sustaining driver  114  and the address driver  116 . The control circuit  110  generates timing signals for the drivers according to the external clock signal CLOCK, the data signal DATA, the vertical synchronous signal VSYNC and the horizontal synchronous signal HSYNC, wherein the clock signal CLOCK represents the data transmittal clock, the data signal DATA represents the display data, and the vertical synchronous signal VSYNC and the horizontal synchronous signal HSYNC are respectively used to define the timing sequences of a frame and a scanning line. The control circuit  110  sends the display data and the clock signal to the address driver  116  and sends the corresponding frame control clock to the Y scanning driver  112  and the sustaining driver  114 . The display data is sequentially transmitted to the address driver  116  by the control circuit  110  and wall charges are built to selected cell by the address discharges. Address discharges are caused by the data pulses of address electrodes A 1 ˜Ap and the scanning pulses of scanning electrodes Y 1 ˜Yn which are sequentially sent by the Y scanning driver  112 . The detailed operation and the control signals for the electrodes are described below.  
           [0009]    [0009]FIG. 3 is a diagram illustrating the manner to drive a conventional PDP to display a frame. As shown in the drawing, each frame is divided into eight sub-fields SF 1 ˜SF 8 . Each sub-field includes three operating period, that is, the reset period R 1 ˜R 8 , the address period A 1 ˜A 8  and the sustain period S 1 ˜S 8 . In the reset period, the residual charges of the former sub-field are cleared to make the initial conditions of all cells before the address period almost the same. In the address period, the address discharges are initiated in the selected cells according to the display data and then wall charges are accumulated. In the sustain period, sustain discharges for displaying are repeatedly initiated and visible light can be produced in the cells which have accumulated charges through the address discharge in the address period. All of the PDP cells are processed at the same time during the reset period R 1 ˜R 8  and the sustain period S 1 ˜S 8 . The address operation is sequentially performed for each cell on the scanning electrodes Y 1 ˜Yn during the address period A 1 ˜A 8 . Moreover, the display brightness is proportional to the length of the sustain period S 1 ˜S 8 . In the example of FIG. 3, the length of the sustain periods S 1 ˜S 8  of the sub-fields SF 1 ˜SF 8  can be set in a ratio of 1:2:4:8:16:32:64:128 to display images in 256 gray scales.  
           [0010]    [0010]FIG. 4 is a timing diagram of the voltage waveforms on the electrodes in a single sub-field of the prior art. The voltage waveforms on the address electrodes Aj are generated by the address driver  116 , the voltage waveforms on the sustaining electrodes X are generated by the X sustaining driver  114 , and the voltage waveforms on the scanning electrodes Y 1 ˜Yn are generated by the Y scanning driver  112 . As shown in the drawing, each sub-field includes the reset period, the address period and the sustain period. The voltage waveforms in each period and the resulted manners are described in detail below.  
           [0011]    At the time point a (in FIG. 4) of the reset period, the voltage of the scanning electrodes Y 1 ˜n is set to 0 V, and a write pulse having a voltage of VS+VW is applied to the sustaining electrode X, in which the voltage VS+VW is larger than the firing voltage between the sustaining electrode X and the scanning electrode Yi. Therefore, the global writing discharge W occurs between the sustaining electrode X and the scanning electrodes Yi. This discharge process accumulates negative charges on the sustaining electrode X and positive charges on the scanning electrodes Yi. The electric field produced by the accumulated negative charges and the positive charges will cancel out the voltage difference between the sustaining electrodes, thus the time of global writing discharge W is very short.  
           [0012]    At the time point b, the sustaining electrode X is set to 0 V, and a sustaining pulse  202  having a voltage of VS is applied to all of the scanning electrodes Y 1 ˜Yn, wherein the value of the voltage VS plus the voltage caused by the charges accumulated between the sustaining electrodes must be larger than the firing voltage between the scanning electrodes Yi and the sustaining electrode X. Thus, the global sustaining discharge S occurs between the sustaining electrode X and the scanning electrodes Yi. Different from the previous discharge process, this discharge process accumulates positive charges on the sustaining electrode X and negative charges on the scanning electrodes Yi.  
           [0013]    At the time point c, the scanning electrode Yi is set to 0 V, an erase pulse  203  having a voltage lower than VS is applied to the sustaining electrode X, and an address pulse having a voltage of −VS can be applied to the address electrode Aj. The erase pulse is used to neutralize a part of the charges. On the scanning electrodes Y 1 ˜Yn, required wall charges are left so that the write operation can proceed with a lower voltage in the sequential address period.  
           [0014]    In the address period, the voltage of the sustaining electrode X and the scanning electrodes Yi are pulled up to VS at the time point d. Then a scan pulse  204  is sequentially applied to the scanning electrodes Y 1 ˜Yn from the time point e, and an address pulse having a voltage of VA is applied to the address electrode Aj at the same time. When a cell of a scanning line turns ON, the write discharge occurs, that is, the corresponding display data is written into the cell.  
           [0015]    After scanning all of the scanning electrodes Y 1 ˜Yn, the sustain period begins. The sustaining electrode X and the scanning electrode Yi are first set to 0 V. Then the sustaining pulses  205  having the same voltage are applied to the sustaining electrode X and the scanning electrodes Yi in an alternate way, i.e., at the time point f and at the time point g. Thus, the cell with the data ON during the address period will irradiate. It should be noted that the waveform of driving signals described above is only an example. The waveform varies in practice, but the same theory is applied.  
           [0016]    As described above, the length of the sustain period is proportional to the displayed brightness. Assume that a frame includes  510  sustain periods, in which each sustaining discharge period has two periods of discharge. The number of sustain periods for the sub-fields SF 1 ˜SF 8  can be 2, 4, 8, 16, 32, 64, 128, and 256, respectively. Therefore, there are  1020  periods of discharge of the sustain period during the display period of a frame. This discharge operation enables a PDP device to display images.  
           [0017]    On the other hand, 2 to 3 discharges, such as global writing discharge, global sustaining discharge and erase discharge, are performed during the reset period to uniformly distribute the wall charges. The discharges during the reset period can also make the PDP device irradiate with a brightness brighter than that produced by the discharge during the sustain period. Roughly speaking, the brightness produced by three periods of discharge during the reset period is about the brightness by five periods of discharge during the sustain period. The ratio of the highest brightness and the lowest brightness for the PDP device is about 1020:(5×8)≅26:1, in which 1 corresponds to the brightness of black. Therefore, the brightness produced by the discharge during the reset period should be as low as possible in order to improve the image quality of black, which is an important factor for displaying images. It is thus a significant issue to reduce the brightness produced by the discharge during the reset period.  
           [0018]    In U.S. patent application Ser. No. 09/810,360 filed Mar. 16, 2001, two novel driving methods have been disclosed to solve the above issue. Associated with one of the driving methods in the cross-referenced application, a novel plasma display panel, is further disclosed in this invention.  
         SUMMARY OF THE INVENTION  
         [0019]    Therefore, an object of the present invention is to provide a plasma display panel, which comprises a first substrate and a second substrate supported in spaced relationship to define a discharge space (or discharge cavity) therebetween, the first and second substrates having opposed surfaces facing each other across the discharge space; a plurality of scanning electrodes (Y 1 ˜Y n ) and a plurality of sustaining electrodes (X 1 ˜X m ) formed on the first substrate, wherein every two of the scanning electrode pairs (Y a , Y a+1 ) and every two of the sustaining electrode pairs (X b , X b+1 ) are alternately arranged on the first substrate, one of the scanning electrodes (for example, Y a+1 ) and adjacent one of the sustaining electrodes (for example, X b ) define a display discharge cell, every two of the scanning electrodes (Y a , Y a+1 ) and every two of the sustaining electrodes (X b , X b+1 ) respectively define priming discharge cells; a plurality of address electrodes formed on the second substrate, perpendicular to the scanning and sustaining electrodes; and a stripe rib structure separating the discharge space into a plurality of stripe discharge regions, substantially parallel to the address electrodes.  
           [0020]    Another object of the present invention is to provide a driving method of plasma display panels, wherein, a plurality of sustaining electrodes (X 1 ˜X m ) and a plurality of scanning electrodes (Y 1 ˜Y n ), configured in a sequence as X 1 -X 2 -Y 1 -Y 2 -X 3 -X 4 . . . X   m−1 -X m -Y n−1 -Y n , and a plurality of address electrodes perpendicularly crossed over the sustaining electrodes and scanning electrodes; wherein, the dark areas XG k  are defined between the sustaining electrodes X 2k−1  and the sustaining electrodes X 2k , and the dark areas YG k  are defined between the scanning electrodes Y 2k  and the scanning electrodes Y 2k−1 . And the display areas D 2k−1 , are defined between the sustaining electrodes X 2k  and the scanning electrodes Y 2k−1 , and the display areas D 2k  are defined between the scanning electrodes Y 2k  and the sustaining electrodes X 2k+1  (n, m and j are integers, and 1 ≦j≦n and m). Wherein, at the first timing point in the reset period, apply a global writing voltage difference V w  to the dark areas XG k  and YG k , but there is no voltage difference in the display areas D 2k−1  and D 2k . The global writing voltage difference is greater than the firing voltage between the adjacent pairs of the sustaining electrodes X 2k−1  and X 2k , and the adjacent pairs of the scanning electrodes Y 2k−1  and Y 2k ; whereby, the gas discharges are occurred in the dark areas XG k  and YG k  for the generation of space charges and wall charges, but do not proceed with the discharge operation in the display areas D 2k−1  and D 2k .  
           [0021]    These and further features, aspects and advantages of the present invention, as well as the structure and operation of various embodiments thereof, will become readily apparent with reference to the following detailed description of a presently preferred, but nonetheless illustrative embodiment when read in conjunction with the accompanying drawings, in which like reference numbers indicate identical or functionally similar elements throughout the enumerated Figures. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]    The drawings referred to herein will be understood as not being drawn to scale except if specially noted, the emphasis instead being placed upon illustrating the principles of the present invention. In the accompanying drawings:  
         [0023]    [0023]FIG. 1 represents the side view of the dissection graph of the cells in a conventional PDP;  
         [0024]    [0024]FIG. 2 represents the block diagram of the PDP device comprised of the PDP in FIG.1;  
         [0025]    FIG. 3  represents the schematic diagram of the conventional PDP in a display mode;  
         [0026]    [0026]FIG. 4 is a timing diagram of the control signals for the electrodes including the address electrodes Ai, the sustaining electrodes X and the scanning electrodes Yi in a single sub-field according to the prior art;  
         [0027]    [0027]FIG. 5 is an embodiment of the PDP according to the present invention.  
         [0028]    [0028]FIG. 6 is a schematic diagram of the sustaining electrodes and the scanning electrodes on the PDP of the present invention, with an electrode structure of XX-YY-XX-YY;  
         [0029]    [0029]FIG. 7 is a timing diagram of the control signal on the sustaining electrodes and scanning electrodes in the reset period of the sub-field, when driving the PDP of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0030]    Reference is now made in detail to an embodiment of the present invention that illustrates the best mode presently contemplated by the inventor(s) for practicing the present invention. Other embodiments are also described herein.  
         [0031]    [0031]FIG. 5 shows an embodiment of the PDP according to the present invention. The PDP  500  comprises a first substrate  501  and a second substrate  502  supported in spaced relationship to define a discharge space  503  therebetween, the first and second substrates ( 501 ,  502 ) having opposed surfaces facing each other across the discharge space  503 ; a plurality of scanning electrodes (Y 1 ˜Y n ) and a plurality of sustaining electrodes (X 1 ˜X m ) formed on the first substrate  501 , wherein every two of the scanning electrodes (for example, Y 1 -Y 2 , Y 3 -Y 4 , . . . ) and every two of the sustaining electrodes (for example X 1 -X 2 , X 3 -X 4 , . . . ) are alternately arranged on the first substrate, as depicted in FIG. 5; a plurality of address electrodes A j  formed on the second substrate  502 , perpendicularly crossing the scanning and sustaining electrodes; and a stripe rib structure, not shown in FIG. 5, separating the discharge space  503  into a plurality of stripe discharge regions, substantially parallel to the address electrodes A j . For the purpose of illustration and brevity, the PDP in FIG. 5 has adopted the configuration of  4  sustaining electrodes (X 1 ˜X 4 ) and 4 scanning electrodes (Y 1 ˜Y 4 ) as the example.  
         [0032]    It is noted that one of the scanning electrodes and adjacent one of the sustaining electrodes define a display discharge cell, every two of the scanning electrodes and every two of the sustaining electrodes respectively define a priming discharge cell. For example, X 2 -Y 1 , Y 2 -X 3  and X 4 -Y 3  define 3 display discharge cells, and X 1 -X 2 , Y 1 -Y 2 , X 3 -X 4  and Y 3 -Y 4  define 4 priming discharge cells.  
         [0033]    Furthermore, the spaced region between every two of the scanning electrodes and every two of the sustaining electrodes are narrower than that between one of the scanning electrodes and adjacent one of the sustaining electrodes. For example, XG 1  and YG 1  are narrower than D 1  in FIG. 5. The PDP  500  further comprises a shadowing mask B X  (for example a black matrix), formed on the first substrate  501 , covering each of the priming discharge cell. Dielectric layers  504  and  505  are respectively formed on the first and second substrates ( 501 ,  502 ), covering the electrodes. A protective layer  506  (for example, a MgO layer) is formed over the dielectric layer  504 , and a fluorescent layer (for example, a phosphor layer)  507  is formed over the second substrate  502 .  
         [0034]    [0034]FIG. 6 is a schematic diagram of the sustaining electrodes and the scanning electrodes on the PDP in FIG. 5. In FIG. 6, the PDP herein includes a plurality of sustaining electrodes (X 1 ˜X 4 ) and scanning electrodes (Y 1 ˜Y 4 ) configured in parallel in the following manner: X 1 X 2 -Y 1 Y 2 -X 3 X 4 -Y 3 Y 4 .  
         [0035]    The spaced region between any of the scanning electrode pairs described: Y 1 -Y 2  and Y 3 -Y 4  along with the spaced region between the sustaining electrode pairs described: X 1 -X 2  and X 3 -X 4  are defined as the dark areas YG 1 , YG 2 , XG 1  and XG 2 . The spaced region between the sustaining electrodes Y j  and X j+1  is defined as the display areas D j  (j≦3). It is noted that the dark areas correspond to the priming discharge cells and the display areas correspond to the display discharge cells.  
         [0036]    [0036]FIG. 7 is a timing diagram of the control signal on each electrode (including both the odd sustaining electrodes X odd  and the even sustaining electrode X even  of the sustaining electrodes X 1 ˜X 4  and the odd scanning electrodes Y odd  and the even scanning electrodes Y even  of the scanning electrodes Y 1 ˜Y 4 ) in the reset period the sub-field of the embodiment of the present invention.  
         [0037]    As illustrated in FIG. 7, at the first timing point t 1  of the reset period, a first driving signal  800  is sent to the odd sustaining electrodes X odd  of the sustaining electrodes X j  and the even scanning electrodes Y even  of the scanning electrodes Y j , and a second driving signal  802  is sent to the odd scanning electrodes Y odd  of the scanning electrodes Y j  and the even sustaining electrodes X even  to the sustaining electrodes X j . As the result of the applications hereof, a global writing voltage difference V w (=V 1 +V 2 ) is applied on the sustaining electrode pairs X 1 -X 2  and X 3 -X 4 , and scanning electrode pairs Y 1 -Y 2  and Y 3 -Y 4 . But no such voltage difference is applied to the X-Y electrode pairs X 2 -Y 1 , Y 2 -X 3  and X 4 -Y 3 .  
         [0038]    In the embodiment, the first driving signal  800  is +180 volts (V 1 =180), and the second driving signal  802  is −180 volts (−V 2 =−180). Hence, there is a global writing voltage difference V w  of 360 volts between the sustaining electrode pairs X 1 -X 2  and X 3 -X 4 , and the scanning electrode pairs Y 1 -Y 2  and Y 3 -Y 4 . Because the global writing voltage difference V w  is greater than the firing voltage between the scanning electrode pairs and the sustaining electrode pairs described above, the sustaining electrode pairs X 1 -X 2 , X 3 -X 4  and scan electrode pairs Y 1 -Y 2 , Y 3 -Y 4  will proceed with the discharge operations in the dark areas XG 1 , XG 2 , YG 1  and YG 2  and accumulate wall charges.  
         [0039]    In addition, the voltage difference between each electrode pairs X 2 -Y 1 , Y 2 -X 3  and X 4 -Y 3  are 0. So, no discharge operation occurs in the display areas D 1 ˜D 3 .  
         [0040]    From the above description, it is clear that the global writing voltage difference V w  in the reset period results in the global writing discharge that occur only between the electrode pairs X 1 -X 2 , X 3 -X 4  and Y 1 -Y 2 , Y 3 -Y 4  in the dark areas XG 1 , XG 2  and YG 1 , YG 2 , but not in the display areas D 1 ˜D 3 . Referring to FIG. 5, it is obvious that the priming discharges (PrD) occur in the priming discharge cells (i.e., the dark area ) during a reset period. Because the dark areas XG 1 , XG 2  and YG 1 , YG 2  are much narrower than the display areas D 1 ˜D 3  and covered by a black matrix B X , thus the brightness displayed during the priming discharge process will be shielded and the contrast of the PDP is enhanced.  
         [0041]    Moreover, the dark area can selectively be shrunk or narrowed to produce better PDP resolvability.  
         [0042]    Yet, the plasma generated during priming discharge can diffuse from priming discharge cells (or dark areas XG j , YG j ) to display discharge cells (or display areas D j ), because of no rib structure parallel to the scanning and sustaining electrodes in this PDP.  
         [0043]    While the invention has been described by way of example and in terms of the preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements as would be apparent to those skilled in the art. Similarly, any process steps described herein may be interchangeable with other steps in order to achieve the same result. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements, which is defined by the following claims and their equivalents.