Abstract:
A plasma display panel (PDP) having a priming electrode is disclosed. The PDP has a first substrate and a second substrate, wherein the second substrate is opposite to the first substrate. The space between the first substrate and the second substrate is defined as a discharge space and is filled with a discharge gas. A sustaining electrode, a scanning electrode and a priming electrode are all positioned on the first substrate along a first direction. An address electrode is positioned on the second substrate perpendicularly with the first direction. The priming electrode outputs a first priming pulse so as to excite the discharge gas and to produce a plurality of discharge ions.

Description:
[0001]    This application incorporates by reference Taiwan application Serial No. 090130455, filed Dec. 07, 2001.  
         BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The invention relates in general to a method for driving a plasma display panel (PDP) and structure thereof, and in particular, to a method for driving a PDP having a priming electrode and structure thereof  
           [0004]    2. Description of the Related Art  
           [0005]    As the fabrication technology of the audio/video (A/V) devices is developing rapidly, higher quality audio and video services are foreseen popular among the users. Take the display device for example. The conventional cathode ray tube (CRT) display cannot provide better audio and video quality than movies, as well as having the disadvantages of large volume, serious radiation issue, and serious image contortion and distortion at the brim region of the screen. The conventional CRT display device certainly cannot satisfy the demands for higher quality audio and video services When the high definition digital television (HDTV) begins to broadcast and the compliant products become more affordable, the CRT displays will be phased out. The plasma display panel (PDP) display, with the advantages of low radiation, low power consumption, and large display area with small volume, will be a very promising HDTV display to replace the CRT display.  
           [0006]    [0006]FIG. 1 shows a three-dimensional diagram of a plasma display panel (PDP) according to a conventional method. The PDP includes a front substrate  102 , a rear substrate  108 . A plurality of sustaining electrodes X and scanning electrode Y are arranged alternately and in parallel on the front substrate  102 . The sustaining electrode X and the scanning electrode Y are covered with a dielectric layer  104 . The dielectric layer is covered with a protective layer  106 , which is made of magnesium oxide (MgO), such that the sustaining electrode X and the scanning electrode Y can be protected.  
           [0007]    A plurality of address electrodes A are formed on the rear substrate  108 , and are orthogonal to the sustaining electrodes X and the scanning electrodes Y respectively. The address electrodes A are covered with a dielectric layer  116 . A plurality of ribs  112  are formed on the dielectric layer  116  and are parallel to the address electrodes A. A fluorescence layer  110  is formed between the adjacent ribs  112  and on the sidewall of the ribs  112 .  
           [0008]    [0008]FIG. 2 illustrates the cross-sectional view of a PDP according to a conventional method. All elements of FIG. 1 are shown in FIG. 2 with the same numerical number, except the ribs  112 . One sustaining electrode X and one scanning electrode Y composes a pair of driving electrodes on the front substrate  102 . One pair of driving electrodes and the corresponding address electrode A on the rear substrate  108  defines a pixel unit  200 . The plurality of the sustaining electrodes X, the scanning electrodes Y, and the address electrodes A commonly defines a plurality of pixel units  200 , disposed in the form of a rectangle matrix. The area between the pixel units  200  is defined as a dark area  203 , as shown in FIG. 2.  
           [0009]    A black matrix  212  on the front substrate  102  is positioned between each pair of driving electrodes, and is also in the dark area  203 . The black matrix  212  is opaque and is used for blocking the light from the exterior environment so as to increase the contrast of the PDP. The space between the front substrate  102  and the rear substrate  108  is called a discharge space  214  and is filled with the discharge gas mixed with Ne and Xe.  
           [0010]    Each pixel unit  200  can be regarded as a capacitive load. The driving circuit provides the alternating current of high frequency for charging each pixel unit  200  through the corresponding sustain electrode X and scan electrode Y The gas in the discharge space  214  is excited, discharged, and then emit UV light. The fluorescence layer  110  absorbs the UV light of specified wavelengths and then emits visible lights.  
           [0011]    [0011]FIG. 3A and 3B illustrate the driving sequence for driving a pixel unit in the form of timing chart according to a conventional method. The driving sequence usually includes a reset period T 1 , an address period T 2 , and a sustain period T 3 . In the reset period T 1 , each pixel unit is reset by respectively applying erase pulses to the corresponding sustain electrode X and the scan electrode Y so that the accumulation of the wall charges for each pixel unit is set to the same. Then, the discharge gas in all pixel units  200  are excited to be discharge ion, and the status of the discharge ions in each pixel unit  200  is reset to the same.  
           [0012]    In the address period T 2 , the image data signals are applied to the pixel units, which are selected to emit lights. In the sustain period T 3 , light pulses are produced by applying alternating voltages across the sustain electrode X and the scan electrode Y of the selected pixel units by the help of the memory effect of the wall charges.  
           [0013]    The reset period T 1  further includes three periods: a first reset period T 11 , a second reset period T 12 , and a third reset period T 13 . During the first reset period T 11 , a first erase pulse P Y1  of about 100 μs duration is applied to all the scan electrodes Y so as to remove the wall charges remaining after the last sustain period. During the second reset period T 12 , a priming pulse P X2  is applied to all the sustain electrodes X so as to produce wall charges on the pixel units again and so as to reset the status of the wall charges to be the same. Since the priming pulse P X2  provides an instant high voltage across the sustain electrode X and scan electrodes Y, the discharge gas in the discharging space  214  is excited, and becomes the wall charges in each pixel unit. During the third reset period T 13 , a second erase pulse P Y3  of about 100 μs duration is applied to the all scan electrodes Y to remove the redundant wall charges in each pixel unit. Another pulse can be applied to the sustain electrode X in order to remove the wall charges remaining after the last sustain period and the discharge ion remaining in this driving sequence respectively during the first reset period T 11  and the third reset period T 13 .  
           [0014]    During the second reset period T 12 , there are two ways to provide a priming pulse P X2 . The first one is to provide a priming pulse P X2  of high level voltage and of positive polarity to the sustaining electrode X as shown in FIG. 3A. The second one is to provide a priming pulse P X2  of positive polarity to the sustaining electrode X and to provide a priming pulse P Y2  of negative polarity to the scanning electrode Y, as shown in FIG. 3B. When the priming pulse P X2  or the voltage difference between the priming pulse P X2  and the priming pulse P Y2  becomes larger, the discharge ion in the discharging space  214  is produced by more quantity and the status consistence of the discharge ion for each pixel unit  200  becomes higher.  
           [0015]    However, the discharge ion induces the fluorescence layer  110  emitting visible light, which is called as the background glow. The background glow during the reset period T 1  will decrease the contrast ratio of the PDP, and lower the quality of the PDP.  
         SUMMARY OF THE INVENTION  
         [0016]    It is therefore an object of the invention to provide a plasma display panel (PDP) with improved the contrast ration, the quality, and the lifetime thereof, wherein a quantity of discharge ions is produced during a reset period.  
           [0017]    The present invention discloses a PDP with a priming electrode. The PDP has a first substrate and a second substrate opposite to each other, wherein the space between the first substrate and the second substrate is defined as a discharge space and is filled with a discharge gas. The PDP is divided into a pixel unit and a dark area and comprises a sustaining electrode, a scanning electrode, a priming electrode, and an address electrode. The sustaining electrode and the scanning electrode are positioned in the pixel unit on the first substrate along a first direction, and the address electrode is positioned on the second substrate perpendicularly with the first direction. The priming electrode is positioned in the dark area on the first substrate along the first direction and outputs a first priming pulse so as to excite the discharge gas and to produce a plurality of discharge ions. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    Other objects, features, and advantages of the invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The description is made with reference to the accompanying drawings in which:  
         [0019]    [0019]FIG. 1 (Prior Art) shows a three-dimensional diagram of a plasma display panel (PDP) according to a conventional method.  
         [0020]    [0020]FIG. 2 (Prior Art) illustrates the cross-sectional view of a PDP according to a conventional method.  
         [0021]    [0021]FIGS. 3A and 3B (Prior Art) illustrate the driving sequence for driving a pixel unit in the form of timing chart according to a conventional method.  
         [0022]    [0022]FIG. 4 illustrates the cross-sectional view of a PDP according to one embodiment of the present invention.  
         [0023]    [0023]FIG. 5A illustrates the driving sequence for driving a pixel unit in the form of timing chart according to one embodiment of the present invention.  
         [0024]    [0024]FIG. 5B illustrates the driving sequence for driving a pixel unit in the form of timing chart according another embodiment of the present invention.  
         [0025]    [0025]FIG. 6A illustrates the cross-sectional view of a PDP according to another embodiment of the present invention.  
         [0026]    [0026]FIG. 6B illustrates the cross-sectional view of a PDP according to another embodiment of the present invention.  
         [0027]    [0027]FIG. 7 illustrates the driving sequence for driving the PDP of FIG. 6A and FIG. 6B in the form of timing chart. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0028]    The present invention installs a priming electrode in the dark area so as to excite the discharge gas and to produce the discharge ion by providing a priming pulse in the reset period.  
         [0029]    [0029]FIG. 4 illustrates the cross-sectional view of a plasma display panel (PDP) according to one embodiment of the present invention. The PDP has a plurality of pixel units  400 , and dark areas  403  are positioned between each pixel units  400 . Comparing with the PDP of FIG. 2, the PDP of FIG. 4 has a priming electrode P in the black matrix  412 , or in the dark area  403 , on the front substrate  402 . The priming electrode P outputs a priming pulse during the reset period as so to excite the discharge gas and to produce the discharge ion.  
         [0030]    [0030]FIG. 5A illustrates the driving sequence for driving a pixel unit  400  in the form of timing chart according to one embodiment of the present invention. The driving sequence usually includes a reset period T 1 , an address period T 2 , and a sustain period T 3 . The reset period T 1  further includes three periods: a first reset period T 11 , a second reset period T 12 , and a third reset period T 13 .  
         [0031]    During the first reset period T 11 , an erase pulse P Y1  of about 100 μs duration is applied to all the scan electrodes Y so as to remove the wall charges remaining after the last sustain period by the voltage difference between the scan electrode Y and the sustain electrode X. During the second reset period T 12 , a priming pulse P P  is applied to all the priming electrodes P so as to produce wall charges in the discharging space  414  by the voltage difference between the priming electrode P and the address electrode. The voltage of the priming pulse P P  is larger than that of the erase pulse P Y1 . During the third reset period T 13 , a erase pulse P Y3  of about 100 μs duration is applied to the all scan electrodes Y to remove the redundant wall charges in each pixel unit  400  by the voltage difference between the scanning electrode and the sustaining electrode. The erase pulse P Y1  and the erase pulse P Y3  can be positive or negative polarity, as well as the priming pulse P P .  
         [0032]    The priming electrode P of the present invention is only used for applying priming pulse during the second reset period T 12 . Since the priming electrode P is positioned in the dark area  403 , the produced discharge ion is also concentrated near the dark area  403 . The visible light from the fluorescence layer  413   b  is blocked by the black matrix  412 , and the background glow received by the user becomes less. Thus, the contrast ratio of the PDP is improved, as well as the quality thereof. Moreover, the UV light emitted from the discharge ion principally illuminates the fluorescence layer  413   b  in the dark area  403 , but not the fluorescence layer  413   a  in the pixel unit  400 . Thus, the lifetime of the fluorescence layer  413   a  in the pixel unit  400  is increased, as well as the fluorescence layer  413 .  
         [0033]    In FIG. 5A, the priming electrode P is used for applying priming pulse during the second reset period T 12 . The sustaining electrode X is used only for applying sustain pulse in the sustain period T 3 , wherein the sustain pulse is interchanged with the scan pulse applied from the scanning electrode Y. No use of the sustaining electrode X and the scanning electrode Y in the second reset period T 12  can simplify the driving sequence, as well as the design of driving circuits respectively for the sustaining electrode X, the scanning electrode Y, and the priming electrode P. Moreover, the sustaining electrode X of FIG. 5A provides a smaller voltage than that of FIG. 3A and FIG. 3B, such that the switch for controlling the sustaining electrode, usually being a MOSFET, is less subject to power consumption.  
         [0034]    [0034]FIG. 5B illustrates the driving sequence for driving a pixel unit  400  in the form of timing chart according another embodiment of the present invention. Compared with FIG. 5A, FIG. 5B has a priming pulse P P2  and another priming pulse P A2 , respectively provided by the priming electrode P and the address electrode A, in the second reset period T 12  so as to excite the gas in the discharging space  414  and to produce the discharge ion. The priming pulse P P2  and another priming pulse P A2  are respectively positive and negative in polarity, or vise versa. The different polarity between the priming pulse P P2  and another priming pulse P A2  can decrease the voltage level of the priming pulse P P2 , compared with the priming pulse P P  of FIG. 5A. Such that the power consumption caused by the priming pulse P P2  can be decreased.  
         [0035]    [0035]FIG. 6A illustrates the cross-sectional view of a plasma display panel (PDP) according to another embodiment of the present invention. Compared with FIG. 4, FIG. 6A provides one common priming electrode P COM  for each pair of adjacent pixel units  600 ,  601 . When the common priming electrode P COM  is used for applying the priming electrode P P  of the driving sequence in FIG. 5A, the gas both in the pixel units  600  and  601  will be excited and the discharge ion used for illuminating the pixel units  600  and  601  will be produced. When the priming pulses P P2 , P A2  with different polarities are respectively applied from the common priming electrode P COM  and address electrode A, the gas both in the pixel units  600  and  601  will be excited and the discharge ion used for illuminating the pixel units  600  and  601  will be produced.  
         [0036]    [0036]FIG. 6B illustrates the cross-sectional view of a plasma display panel (PDP) according to another embodiment of the present invention. Compared with FIG. 6A, FIG. 6B provides one common priming electrode P COM  for each pair of adjacent pixel units  600 ,  601 , wherein the common priming electrode P COM  is positioned between the scanning electrode Y 1  of the pixel unit  600  and the scanning electrode Y 2  of the pixel unit  601 .  
         [0037]    [0037]FIG. 7 illustrates the driving sequence for driving the PDP of FIG. 6A and FIG. 6B in the form of timing chart. During the second reset period T 12 , a priming pulse P P2  with positive polarity is applied to the common priming electrode P COM , and a priming pulse P Y2  with negative polarity is applied to the scanning electrode Y 1  of the pixel unit  600  and the scanning electrode Y 2  of the pixel unit  601 . In this way, the gases both in the pixel units  600  and  601  will be excited and more discharge ion will be produced.  
         [0038]    Other than the advantages described in FIG. SA and FIG. 5B, the PDP structure of FIG. 6A and FIG. 6B further has the characteristics of low number for the priming electrodes. Therefore, the PDP can have a simpler structure, as well as the design of the driving circuit.  
         [0039]    From the above description, the present invention improves the contrast ration, the quality, and the lifetime of the PDP by applying a priming electrode in the dark area. Moreover, the driving sequence and the driving circuit of the present invention are simplified, and the power consumption is decreased.  
         [0040]    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 embodiment. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.