Abstract:
A plasma display panel and a method of driving the same that are capable of improving the discharge efficiency using a direct current type discharge and a radio frequency discharge. In the panel, an address discharge for selecting a display cell is generated by a direct current discharge. A data written into the selected cell is displayed by a radio frequency discharge. The address discharge of direct current type and the radio frequency discharge are allowed to maximize the brightness and the discharge efficiency.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a plasma display device, and more particularly to a plasma display panel that is capable of improving the discharge efficiency using a direct current discharge and a radio frequency discharge. Also, the present invention is directed to a method of driving the same. 
     2. Description of the Related Art 
     Recently, a plasma display panel(PDP) feasible to the fabrication of large-scale panel has been available for a flat panel display device. The PDP controls a discharge interval of each pixel to display a picture. Such a PDP is classified into a direct current(DC) type and an alternating current(AC) type in accordance with its electrode structure. An electrode is directly exposed to a discharge gas in the case of a DC-type PDP while an electrode is indirectly exposed through a dielectric material in the case of an AC-type PDP. 
     Referring to FIG. 1, there is shown a discharge cell structure arranged in a matrix pattern in an AC-type PDP with three electrodes. The PDP discharge cell includes an upper plate having a sustaining electrode pair  12 A and  12 B formed on an upper substrate  10  sequentially, an upper dielectric layer  14  and a protective film  16 , and a lower plate having an address electrode  20  formed on a lower substrate  18  sequentially, a lower dielectric layer  22 , a barrier rib  24  and a fluorescent layer  26 . The upper substrate  10  is spaced from the lower substrate  18  by the barrier rib  24 . The sustaining electrode pair  12  consists of a scanning/sustaining electrode and a sustaining electrode. A scanning signal for a panel scanning and a sustaining signal for a discharge sustaining are applied to the scanning/sustaining electrode while a sustaining signal is applied to the sustaining electrode. A charge is accumulated in the upper dielectric layer  14  and the lower dielectric layer  22 . The protective film  16  prevents a damage of the upper dielectric layer  14  caused by the sputtering to prolong a life of the PDP as well as to improve an emission efficiency of secondary electrons. Usually, MgO is used as the protective film  16 . The address electrode  20  is crossed with the sustaining electrode pair  12 . Data signals for selecting cells to be displayed are applied to the address electrode  20 . The barrier rib  24  is formed in parallel to the address electrode  20 . The barrier rib  24  prevents an ultraviolet ray produced by the discharge from being leaked into the adjacent discharge cells. The fluorescent layer  26  is coated on the surface of the lower dielectric layer  22  and the barrier rib  24  to generate any one of red, green and blue visible lights. An inactive gas for a gas discharge is sealed into the inner discharge space. 
     After the PDP discharge cell with such a structure was selected between the address electrode  20  and the scanning/sustaining electrode, it sustains the discharge by a surface discharge between the sustaining electrode pair  12 . The fluorescent body  26  is luminous by an ultraviolet generated during the sustaining discharge at the PDP discharge cell and hence a visible light is emitted into the exterior of the discharge cell. As a result, the PDP including the discharge cells displays a picture. In this case, the PDP controls a discharge-sustaining interval, that is, a sustaining discharge frequency of the cell to implement a gray scale required for an image display. In this respect, the sustaining discharge frequency becomes an important factor determining the brightness and a discharge efficiency of the PDP. For the sake of such a sustaining discharge, a sustaining pulse having a duty ratio of 1, a frequency of 200 to 300 kHz and a width of about 20 μs are alternately applied to the sustaining electrode pair  12 A and  12 B. In response to the sustaining pulse, the sustaining discharge generates only one time at an extremely short instant per sustaining pulse. Charge particles generated by the sustaining discharge move a discharge path formed between the sustaining electrode pair  12 A and  12 B depending on the polarity of the sustaining electrode pair  12 A and  12 B to thereby form a wall charge on the surface of the upper dielectric layer  14 . This wall charge cancels a voltage applied between the sustaining electrode pair  12 A and  12 B to reduce a discharge voltage loaded in the discharge space, thereby stopping the sustaining discharge. As described above, the sustaining discharge is generated only once at an extremely shorter instant than a width of the sustaining pulse. Most of the remaining time is wasted for a preparation step for the formation of wall charge and the next sustaining discharge. For this reason, since the conventional PDP has a very short real discharge interval compared with the entire discharge interval, it has low brightness and low discharge efficiency. Referring now to FIG. 2, there is shown the structure of a discharge cell arranged in a matrix pattern in a DC-type PDP. The DC-type discharge cell includes a cathode  30  formed on an upper substrate  10 , an anode  32  and an auxiliary anode  34  each formed on a lower substrate  18 , and a barrier rib  24  formed between the upper substrate  10  and the lower substrate  18  to provide a main discharge space  31  and an auxiliary discharge space  33 . The DC-type discharge cell consists of a main discharge cell provided with the main discharge space  31  and an auxiliary discharge cell provided with the auxiliary discharge space  33 . Charged particles produced at the auxiliary discharge cell are introduced into the main discharge cell to cause a display discharge at the main discharge cell. The barrier rib  24  is formed in a lattice structure to prevent a mis-discharge between the adjacent cells caused by a diffusive movement of the charge particles generated by the auxiliary discharge. The anode  32  is formed on the lower substrate  18  provided with the main discharge space  31  while the auxiliary anode  34  is formed on the lower substrate  18  provided with the auxiliary discharge space  33 . A current limiting resistor  36  is provided between the anode  32  and the lower substrate  18  to limit an overshoot of the discharge current. The DC-type discharge cell having the structure as described above generates the discharge between the cathode  30  and the anode  32  and makes use of an auxiliary discharge in the auxiliary discharge cell so as to lower a discharge voltage in the main discharge cell. In other words, by the auxiliary discharge generated from the cathode  30  and the auxiliary anode  34  in the auxiliary discharge cell, charged particles are produced. Then, the charged particles are moved into the main discharge space  31  through a hole defined between the main discharge space  31  and the auxiliary discharge space  33  and used for a display discharge caused by the cathode  30  and the anode  32 . 
     The DC-type PDP has an advantage in that it has more excellent contrast than the AC-type PDP because a light generated by the auxiliary discharge is shut off by means of a black matrix(not shown) formed on the upper plate. Also, in view of a fact that the AC-type PDP has a time interval at which the discharge is stopped even when a discharge voltage pulse is being applied by a wall charge formed in the dielectric layer while the DC-type PDP generates a continuous discharge when a discharge voltage pulse is being applied, it can be said that the DC-type PDP has a relatively good discharge efficiency. However, the DC-type PDP has a disadvantage in that total discharge efficiency is low due to an energy loss caused by the auxiliary discharge and the resistance. 
     Further, the AC-type and DC-type PDP rely on only a negative glow discharge having a poor discharge efficiency because the size of the discharge cell is too small, that is, because a distance between the electrodes is very short. In addition, the conventional AC-type and DC-type PDP has a problem in that most of an electric energy applied to the discharge space  21  is wasted to cause a low brightness because a negative glow is used at the time of their luminescence. 
     Referring to FIG. 3, there is shown the structure of a typical glow discharge tube. It can be seen from FIG. 3 that a negative glow  42 A generates in the neighborhood of the cathode  38  while a positive column  42 B appears in a shape of tube at the anode  40  when a distance between two electrodes  38  and  40  is sufficiently long. A space between the negative glow  42 A and the positive column  42 B is called the Faraday dark space. In this case, the positive column  42 B is disappeared when a distance between two electrodes  38  and  40  is shortened and the negative glow  42 A is reduced when it is more and more shortened. Accordingly, the brightness and the discharge efficiency are lowered. A problem resulting from such low brightness and discharge efficiency becomes serious as a higher resolution is needed, thereby causing more deteriorated brightness and discharge efficiency. Accordingly, there has been attempted a scheme of utilizing a positive column for providing a good discharge efficiency by changing the discharge area or lengthening the discharge path so as to increase the brightness and discharge efficiency within the limited space of the discharge cell. However, to lengthen a distance between the electrodes for the purpose of lengthening the discharge path raises the discharge voltage to cause many difficulties such as a development of a high voltage driving integrated circuit(IC), etc. As a result, it is necessary to provide a novel discharge and driving mechanism that is capable of lengthening the discharge path with the aid of other discharge mechanism in the existent discharge cell structure. 
     In order to solve such a low brightness and discharge efficiency problem in the PDP, we had filed a patent application regarding to a method of utilizing a radio frequency discharge using a radio frequency of hundreds of MHz as a display discharge. In the case of the radio frequency discharge, electrons do a vibrating motion by a radio frequency signal, so that a display discharge is sustained in a time interval when a radio frequency signal is applied. More specifically, if a radio frequency voltage signal having the polarity alternating continuously is applied to any one of two opposed electrodes, then electrons within the discharge space is moved into one electrode or the other electrode in accordance with the polarity of the voltage signal. When electrons are moved toward any one electrode, if the polarity of the applied radio frequency voltage signal is changed before the electrons arrive at the electrode, then a movement speed of the electrons is gradually decreased and ultimately a movement direction of the electrons is changed, so that the electrons are moved toward the opposite electrode. If the polarity of a radio frequency voltage signal applied to an electrode is changed before electrons within the discharge space arrive at the electrode, then the electrons do an oscillating motion between the two electrodes. Accordingly, when the radio frequency voltage signal is being applied, the ionization, excitation and transition of gas particles are generated continuously without an extinction of electrons. As described above, the display discharge is sustained during most of discharge time, so that the brightness and discharge efficiency of the PDP can be improved. Such a radio frequency discharge has a physical characteristic identical to a positive column in the glow discharge structure. However if both the address discharge and the sustaining discharge are generated by the radio frequency discharge, then a driving of the PDP becomes not only complicated during the addressing, but also a high voltage is required to cause a rise of the power consumption. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a PDP that is capable of improving a discharge efficiency thereof using a radio frequency as well as carrying out a stable addressing. 
     Further object of the present invention is to provide a PDP driving method that is adaptive for driving said PDP using a radio frequency. 
     In order to achieve these and other objects of the invention, according to one aspect of the present invention, an address discharge for selecting a display cell is generated by a direct current discharge, and a data written into the selected cell is displayed by a radio frequency discharge. To this end, a PDP according to the present invention a direct current discharging electrode part for applying a direct current to cause a writing discharge within the discharge cells, said electrode part having electrodes crossed with each other; and a radio frequency discharging electrode part for applying a radio frequency voltage to generate a sustaining discharge caused by a radio frequency discharge within the discharge cells. 
     According to another aspect of the present invention, each of discharge cells in the PDP includes first and second substrates opposed to each other; a cathode formed on the first substrate; a barrier rib formed between the first and second substrates to provide an auxiliary discharge space and a main discharge space; an anode formed on the second substrate provided with the main discharge space; an auxiliary anode formed on the second substrate provided with the auxiliary discharge space; and first and second radio frequency electrodes formed in opposition to the barrier rib providing the main discharge space. 
     According to still another aspect of the present invention, a method of driving a plasma display panel includes a writing discharge step of responding to an opposite polarity of direct current voltage applied to each of the address electrode and the scanning electrode formed to be opposed to each other to cause a direct current discharge, thereby selecting a display cell; and a sustaining discharge step of sustaining a discharge within the selected display cell with a radio frequency discharge caused by a radio frequency voltage applied to each of first and second radio frequency electrodes. 
     According to still another aspect of the present invention, a method of driving a plasma display panel includes the steps of initiating a radio frequency discharge at the entire panel; sustaining the radio frequency discharge and generating an erasure discharge selectively in accordance with a gray level of a display cell to stop the radio frequency discharge; and stopping the radio frequency discharge in all the display cells when a sustaining discharge interval is terminated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects of the invention will be apparent from the following detailed description of the embodiments of the present invention with reference to the accompanying drawings, in which: 
     FIG. 1 is a sectional view showing the structure of a discharge cell in the conventional AC-system PDP; 
     FIG. 2 is a sectional view showing the structure of a discharge cell in the conventional DC-system PDP; 
     FIG. 3 is a schematic sectional view showing the structure of the conventional glow discharge tube; 
     FIG. 4 is a sectional view showing the structure of a discharge cell in a PDP according to an embodiment of the present invention; 
     FIG. 5 is waveform diagrams of a voltage for driving the discharge cell in FIG. 4; 
     FIG. 6 is a sectional view showing the structure of a discharge cell in a PDP according to another embodiment of the present invention; 
     FIG. 7 is a plan view of the lower plate shown in FIG. 6; 
     FIG.  8 A and FIG. 8B are sectional views of the lower plate taken along A-A′ line and B-B′ line in FIG. 7, respectively; 
     FIGS. 9A to  9 D are sectional views showing a driving mechanism in the discharge cell in FIG. 6 step by step; 
     FIG. 10 is a schematic view representing an electrode arrangement in a PDP having the discharge cell shown in FIG. 6 in a matrix pattern; 
     FIG. 11 is waveform diagrams of driving voltages applied to electrode lines shown in FIG. 10; 
     FIG. 12 is a sectional view showing the structure of a discharge cell in a PDP according to still another embodiment of the present invention; 
     FIG.  13 A and FIG. 13B are sectional views of the lower plate taken along A-A′ line and B-B′ line in FIG. 12, respectively; 
     FIGS. 14A to  14 C are sectional views showing a driving mechanism in the discharge cell in FIG. 12 step by step; 
     FIG. 15 is a schematic view representing an electrode arrangement in a PDP having the discharge cell shown in FIG. 12 in a matrix pattern; and 
     FIG. 16 is waveform diagrams of driving voltages applied to electrode lines shown in FIG.  15 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 4, there is shown a discharge cell in a DC-type PDP according to an embodiment of the present invention. The discharge cell includes a cathode  30  formed on an upper substrate  10 , an anode  32  and an auxiliary anode  34  each formed on a lower substrate  18 , a barrier rib  24  provided between the upper substrate  10  and the lower substrate  18 , and first and second radio frequency electrodes  44  and  46  opposed to the barrier rib  24  provided with a main discharge space  31 . The upper substrate  10  as a display screen of a picture is arranged in opposition to the lower substrate  18 . The barrier rib  24  is formed between the upper substrate  10  and the lower substrate  18  to provide the main discharge space  31  and an auxiliary discharge space  33 . In addition, the barrier rib  24  is formed in a lattice structure to prevent a mis-discharge between the adjacent cells caused by a diffusive movement of the charge particles generated by the auxiliary discharge. The anode  32  is formed on the lower substrate  18  provided with the main discharge space  31  while the auxiliary anode  34  is formed on the lower substrate  18  provided with the auxiliary discharge space  33 . The anode  32  and the auxiliary anode  34  are connected to each bus line(not shown) arranged in a direction crossing with the cathode  30  formed on the upper substrate  10 . A current limiting resistor  36  is provided between the anode  32  and the lower substrate  18  to limit an overshoot of the discharge current as well as to restrain a sputtering into the cathode. Each of the first and second radio frequency electrodes  44  and  46  are formed in opposition to the barrier rib  24  provided with the main discharge space  31 . For instance, the first and second radio frequency electrodes  44  and  46  are formed in the diagonal direction in opposition to each other. A fluorescent material(not shown) is coated on the surface of the barrier rib  24  and the peripheral of the anode  32  in the main discharge space  31 . A method of driving the DC-type discharge cell with the above-mentioned structure will be described in detail with reference to driving waveform diagrams in FIG.  5 . 
     First, a scanning pulse is applied to the cathode  30  and an auxiliary discharging pulse is applied to the auxiliary anode  34 , to thereby generate an auxiliary discharge at the auxiliary discharge space  33 . Charged particles produced by the auxiliary discharge are diffused, via a hole at the barrier rib  24 , into the main discharge space  31 . At the same time, a write pulse is applied to the anode  32  to generate the discharge at the main discharge space  31 . Such a discharge is sustained by a sustaining pulse applied to the cathode  30 . By this sustaining discharge, electrons excite gas atoms and molecules sealed in the main sustaining space  31  while moving from the cathode  30  into the anode  32  to emit a vacuum ultraviolet ray. During the sustaining discharge, a radio frequency voltage is applied between the first and second radio frequency electrodes  44  and  46  to change an electric field of the main discharge space  31 . More specifically, a radio frequency voltage is applied to the first radio frequency electrode  44  and a center voltage Vb of the radio frequency voltage is applied to the second radio frequency electrode  46 , to thereby generate an oscillating electric field at the main discharge space  31 . By this oscillating electric field, a motion direction of electrons being moved from the cathode  30  into the anode  32  is disturbed. In other words, the electrons are moved in a zigzag direction at the main discharge space  31  by the oscillating electric field. Accordingly, the electrons excite greater amount of gas atoms and molecules sealed in the main discharge space  31  while moving along a considerably long path. As a result, much more vacuum ultraviolet rays are generated to radiate a fluorescent body, so that the brightness and the discharge efficiency can be improved. 
     In this case, a radio frequency voltage applied to the first radio frequency electrode  44  is applied in such a manner to have a desired time difference from a sustaining pulse applied to the cathode  30  so as not to make an affect to an initiation of the sustaining discharge. Further, in order to prevent charged particles caused by the sustaining discharge(or the direct current discharge) from being leaked into the barrier rib  24 , the voltage and frequency values of a radio frequency voltage signal applied to the first radio frequency electrode  44  are selected in such a manner that an oscillation width of electrons being moved from the cathode  30  into the anode  32  by the sustaining discharge is much smaller than that of the main discharge space  31 . Herein, the radio frequency voltage pulse may have various waveform shapes such as rectangular wave and sinusoidal wave, etc. 
     As described above, the DC-type PDP according to the present invention applies a radio frequency voltage to a motion path of charged particles caused by the direct current discharge to lengthen a discharge path of the charged particles, so that it can improve the brightness and the discharge efficiency. 
     Referring now to FIG. 6, there is shown a PDP discharge cell with a DC-type discharge structure according to another embodiment of the present invention. Further, FIG. 7 is a plan view of the lower substrate of the discharge cell shown in FIG.  6 . FIG.  8 A and FIG. 8B are sectional views of the lower substrate taken along A-A′ line and B-B′ line in FIG. 7, respectively. In FIG. 6 to FIG. 8B, the discharge cell includes an upper plate having a first radio frequency electrode  48  provided on an upper substrate  10 , a lower plate having a second radio frequency electrode  50 , a dielectric layer  52 , a scanning electrode  54 , an insulating pattern  56  and an address electrode  58  formed sequentially on a lower substrate  18 , and a barrier rib  24  coated with a fluorescent material  26 . The scanning electrode  54  and the address electrode  58  carry out an address discharge in a DC-type discharge structure to produce priming particles, that is, charged particles as a seed of the radio frequency discharge. An insulating pattern  56  for insulating the scanning electrode  54  and the address electrode  58  is formed in a line shape at the lower portion of the address electrode  58  in such a manner that two electrodes  54  and  58  has a DC-type discharge structure exposed directly to the discharge space. Since the scanning electrode  54  and the address electrode  58  is adjacent to each other with having the insulating pattern  56  therebetween, they cause an address discharge by a lower voltage. A resistor layer(not shown) may be formed under the scanning electrode  54  or the address electrode  58 . This resistor layer is used as a current limiting resistor for restraining the overshoot of a discharge current and the sputtering. The first radio frequency electrode  48  consists of a transparent electrode so as not to interfere a luminous light. A radio frequency voltage with a frequency of several MHz to hundreds of MHz is applied to the first radio frequency electrode  48  and a center voltage(i.e., a reference voltage) of the radio frequency voltage is applied to the second radio frequency electrode  50 , thereby causing a radio frequency discharge. The dielectric layer  52  is responsible for an insulating layer between the second radio frequency electrode  50  and the scanning electrode  54 . The barrier rib  24  formed between the upper substrate  10  and the lower substrate  18  plays a role to provide a discharge space excluding an optical interference from the adjacent discharge cells as well as to support the upper substrate  10  and the lower substrate  18 . The fluorescent material  26  is coated on the surface of the barrier rib  24 . A discharge gas is injected into the discharge space. The Penning effect is mainly utilized for the general AC or DC discharge. On the other hand, in the radio frequency discharge, positive ions keep almost a stationary state and only electrons excite gas atoms while doing an oscillating motion, so that it is effective to use Xe gas with a relatively low excitation energy level as the discharge gas. In this case, since a discharge voltage is raised if the Xe gas only is used, a mixture gas of He and Ne, etc can be used so as to improve the efficiency. The general AC or DC discharge has a disadvantage in that the color purity becomes poor due to a radiation of an orange color generated at an excitation level of Ne during the Penning action. Otherwise, the radio frequency discharge concentrates an energy level of electrons on the excitation energy of Xe to prevent the radiation of an orange color generated from Ne, so that it can improve the color purity. 
     FIGS. 9A to  9 C are sectional views representing a driving mechanism of the discharge cell in FIG. 6 step by step. Referring to FIGS. 9A and 9B, a scanning pulse and a data pulse is simultaneously applied to each of the scanning electrode  54  and the address electrode  58  to generate an address discharge of DC type at the discharge cell. By this address discharge, charged particles are produced at the discharge space as shown FIG.  9 C. These charged particles, that is, electrons and positive ions form a current path between the first and the second radio frequency electrodes  48  and  50 . A discharge current flows via the current path when the scanning pulse and the data pulse is being applied. In other words, electrons as a seed of the radio frequency sustaining discharge are produced within the discharge space by the address discharge. Then, a radio frequency pulse is applied to the first radio frequency electrode  48  and a reference voltage of a radio frequency pulse is applied to the second radio frequency electrode  50 , thereby generating an oscillating electric field at the discharge space. By this oscillating electric filed, the electrons ionize and excite discharge gases continuously while doing an oscillation motion within the discharge space as shown in FIG. 9D to thereby emit more lots of vacuum ultraviolet rays. As a result, a luminous amount of the fluorescent body is increased the vacuum ultraviolet rays. Meanwhile, since electrons as a seed of the radio frequency discharge are not produced within the discharge space, a radio frequency discharge fails to be generated in a discharge cell in which an address discharge does not occur. The radio frequency discharge can be stopped by applying a desired level of DC erasing voltage to any one of the scanning electrode  54 , the address electrode  58 , and the first and second radio frequency electrodes  40  and  50 . In this case, electrons are vanished toward an electrode to which an erasing pulse is applied, thereby terminating the radio frequency discharge. 
     FIG. 10 shows an electrode arrangement of a PDP having the discharge cell in FIG. 6 arranged in a matrix pattern. In FIG. 10, the PDP includes n address electrode lines X 1  to Xn, m scanning electrodes Y 1  to Ym crossed and arranged alternately with the address electrode lines X 1  to Xn, and first and second radio frequency electrodes RF 1  and RF 2 . Discharge cell are provided at intersections among the address electrode lines X 1  to Xn, scanning electrodes Y 1  to Ym and the first and second radio frequency electrode lines RF 1  and RF 2 . A scanning pulse is line-sequentially applied to the scanning electrode lines Y 1  to Ym, and a data pulse synchronized with the scanning pulse is applied to the, address electrode lines X 1  to Xn in a horizontal line unit. A radio frequency voltage is commonly applied to the first radio frequency electrode line RF 1  while a reference voltage of the radio frequency voltage is commonly applied to the second radio frequency electrodes RF 2 . Herein, the first radio frequency electrode line RF 1  and/or the second radio frequency electrode line RF 2  is fabricated in a shape of electrode plate so as to improve the discharge uniformity. FIG. 11 represents waveform diagrams of drive signals for driving the PDP shown in FIG.  10 . In FIG. 11, XS represents a drive waveform applied to the address electrode lines X 1  to Xn; YS 1  and TS 2  do drive waveforms applied to the first and second scanning electrode lines Y 1  and Y 2 , respectively; and RFS 1  and RFS 2  do drive waveforms applied to the first and second radio frequency electrode lines RF 1  and RF 2 , respectively. A scanning pulse −Vy is sequentially applied to the scanning electrode lines Y 1  to Ym, and a data pulse Vx corresponding to one bit of each pixel data is applied to the address electrode lines X 1  to Xn in a horizontal line unit with being synchronized with the scanning pulse. Accordingly, an address discharge of DC type is sequentially generated in a horizontal line unit in accordance with a logical value of the data pulse. At this time, a radio frequency voltage Vr is applied to the first radio frequency electrode lines RF 1  while a reference voltage, that is, a direct current bias voltage Vb is applied to the second radio frequency electrode line RF 2 . By this radio frequency voltage, a radio frequency discharge is continuously generated at discharge cells producing charged particles by the address discharge to display a desired brightness. In this case, since the radio frequency discharge is generated continuously with the address discharge generated in a line sequence, it is line-sequentially initiated and sustained. Further, electrons having done an oscillation motion in the discharge space is attracted and vanished into the scanning electrode lines Y 1  to Ym by an erasing voltage pulse Vcy applied to the scanning electrode lines Y 1  to Ym sequentially, thereby stopping the radio frequency discharge. Accordingly, the brightness can be controlled by adjusting an application time of the erasing voltage pulse Vcy. 
     Referring now to FIG. 12, there is shown a discharge cell of a PDP according to still another embodiment of the present invention. FIG.  13 A and FIG. 13B are plan views showing the structure of the upper plate and the lower plate of the discharge cell in FIG. 12, respectively. The discharge cell includes a first radio frequency electrode  60  and a scanning electrode  62  arranged, in parallel, on an upper substrate  10 , a second radio frequency electrode  66  and an address electrode  68  arranged, in parallel, on a lower substrate  18 , and a barrier rib  24  coated with a fluorescent material  26 . The first radio frequency electrode  60  and the scanning electrode  62  are arranged, in parallel, on the upper substrate  10  in the horizontal direction, whereas the second radio frequency electrode  66  and the address electrode  68  are arranged, in parallel, on the lower substrate  18  in the vertical direction. The first and second radio frequency electrodes  60  and  66  initiate and sustain a radio frequency discharge. The scanning electrode  62  and the address electrode  68  stop the radio frequency discharge in accordance with a logical value of the data pulse. The scanning electrode  62  and the address electrode  68  has a DC-type discharge structure. In light of a principle of the radio frequency discharge, positive ions sustain almost a stationary state because they have a relatively heavy mass compared with electrons and, therefore, fail to move instantly in accordance with a change in a radio frequency field. Accordingly, a protective layer is not need on the upper plate because an ion impact to the electrodes does not exist during the radio frequency discharge, but a protective layer  36  may be formed only on the first radio frequency electrode  60  as shown in FIG. 13A so as to improve a generation efficiency of secondary electrons. The fluorescent material  26  is coated on the surface of the barrier rib  24  and the lower substrate  18  provided with the second radio frequency electrode  66  and the address electrode  26 . In such a discharge cell, any one of the upper substrate  10  and the lower substrate  18  can be used as a picture display surface. In this case, electrodes arranged at the substrate used as the picture display surface are formed of transparent electrodes capable of transmitting a light. 
     FIGS. 14A and 14C are sectional views showing a driving mechanism of the discharge cell in FIG. 12 step by step. A radio frequency voltage able to initiate the discharge is applied to the second radio frequency electrode  66  and a bias voltage, that is, a center voltage of a radio frequency voltage is applied to the first radio frequency electrode  60 , thereby initiating a radio frequency discharge at the discharge cell as shown in FIG.  14 A. Then, a voltage value of the radio frequency voltage applied to the second radio frequency electrode  66  is lowered into such a voltage value that can sustain the discharge while the bias voltage applied to the first radio frequency electrode  60  being sustained as it was. Accordingly, in the discharge cell, electrons ionize and excite discharge gases while doing an oscillation motion within the discharge space as shown in FIG. 14B to emit a vacuum ultraviolet ray, thereby radiating the fluorescent body  26 . Subsequently, by applying a positive DC voltage to the scanning electrode  62  and, at the same time, applying a negative DC voltage to the address electrode  68 , electrons are attracted into the scanning electrode  62  applied with the positive voltage with reducing their oscillation width to vanish charged particles, thereby stopping the discharge. 
     FIG. 15 shows an electrode arrangement of a PDP having the discharge cell in FIG. 12 arranged in a matrix pattern. In FIG. 15, the PDP includes first radio frequency electrode lines RF 1  and scanning electrode lines Y 1  to Ym arranged alternately, and second radio frequency electrode lines RF 2  and address electrode lines X 1  to Xn crossing with the first radio frequency electrode lines RF 1  and the scanning electrode lines Y 1  to Ym. A discharge cell  45  is provided at each intersection between the first radio frequency electrode lines RF 1  and the scanning electrode lines Y 1  to Ym and between the second radio frequency electrode lines RF 2  and the address electrode lines X 1  to Xn. The first and second radio frequency electrode lines RF 1  and RF 2  are used to initiate and sustain a radio frequency discharge. The address electrode lines X 1  to Xn and the scanning electrode lines Y 1  to Ym are used to erase the discharge selectively in accordance with a data while scanning the screen. In this case, the address electrode lines X 1  to Xn and the scanning electrode lines Y 1  to Ym are driven individually, whereas the first and second radio frequency electrode lines RF 1  and RF 2  are driven commonly. 
     FIG. 16 represents waveform diagrams of drive signals for driving the PDP shown in FIG.  15 . The driving waveforms in FIG. 15 are applied to a selective erasing method that erasing the discharge in discharge cells without any display data in a row line unit while initiating a radio frequency discharge at all the discharge cells simultaneously and then sustaining the radio frequency discharge. First, a radio frequency voltage Vrf with a voltage for the discharge initiation is applied to the second radio frequency electrode lines RF 2  and a center voltage Vc of the radio frequency voltage is applied to the first radio frequency electrode lines RF 1 , thereby initiating a radio frequency discharge at all the discharge cells. Next, a voltage value of the radio frequency voltage applied to the second radio frequency electrode lines RF 2  is lowered into a discharge sustaining voltage value Vrs to sustain the radio frequency discharge. Then, a scanning pulse (i.e., an erasing pulse) with a positive voltage value Va 1  is line-sequentially applied to the scanning electrode lines Y 1  to Ym. At the same time, a data pulse with a negative voltage value −Va 2  is synchronized with the scanning pulse (or the erasing pulse) and applied to the address electrode lines X 1  to Xn in a line unit in correspondence with a low logical value (i.e., ‘0’) of video data. Accordingly, the radio frequency discharge is erased at the discharge cells to which a low logical value of data pulse is applied, whereas the discharge is sustained at the discharge cells to which a low logical value of data pulse is not applied by the radio frequency voltage applied between the first and second radio frequency electrodes RF 1  and RF 2 . At this time, a voltage value Va 1  of the scanning pulse (or the erasing pulse) applied to the scanning electrode lines Y 1  to Ym is properly enlarged compared with a voltage value Va 2  of the data pulse applied to the address electrode lines X 1  to Xn, thereby minimizing an interference upon addressing of other lines. If a desired discharge sustaining interval for displaying a certain brightness lapses, then an erasing voltage(Ve) pulse with a relatively large width is line-sequentially applied to the scanning electrode liens Y 1  to Yn to stop the radio frequency discharge having been sustained in a desired time interval. In this case, the brightness control is permitted by adjusting an application time of the erasing voltage(Ve) pulse in accordance with a gray level of the display cell. 
     As described above, in the PDP according to the present invention, an address discharge of DC type and a radio frequency discharge is allowed, so that the brightness and the discharge efficiency can be maximized. Also, according to the present invention, charged particles formed by the DC priming discharge is used for the sustaining discharge to allow an easy radio frequency discharge, so that a low power consumption is permitted. 
     Although the present invention has been explained by the embodiments shown in the drawings described above, it should be understood to the ordinary skilled person in the art that the invention is not limited to the embodiments, but rather that various changes or modifications thereof are possible without departing from the spirit of the invention. Accordingly, the scope of the invention shall be determined only by the appended claims and their equivalents.