JP4649825B2 - Driving method of plasma display device - Google Patents

Description

  The present invention relates to a driving method of a plasma display apparatus.

  The structure of an AC type plasma display panel (hereinafter referred to as a panel) is shown in FIG. As shown in FIG. 3, a striped display in which a scanning electrode 4 as a first electrode and a sustaining electrode 5 as a second electrode are paired on a substrate 1 made of a transparent front glass substrate. A plurality of pairs of electrodes are formed. The scan electrode 4 and the sustain electrode 5 are respectively composed of transparent electrodes 4a and 5a and buses 4b and 5b made of silver or the like electrically connected to the transparent electrodes 4a and 5a. A dielectric layer 2 is formed on the front substrate 1 so as to cover the plurality of pairs of electrodes, and a protective film 3 is formed on the dielectric layer 2.

  A data electrode 8 covered with an insulator layer 7 is disposed on a substrate 6 made of a glass substrate on the back side, and a partition wall 9 is formed in parallel with the data electrode 8 on the insulator layer 7 between the data electrodes 8. The phosphor 10 is provided over the surface of the insulator layer 7 and the side surface of the partition wall 9. Further, the substrate 1 and the substrate 6 are arranged to face each other with the discharge space 11 interposed therebetween so that the scan electrode 4 and the sustain electrode 5 and the data electrode 8 are orthogonal to each other, and helium is used as the discharge gas in the discharge space 11. , Neon, argon, or xenon, by sealing at least one kind of rare gas, sandwiched between two adjacent barrier ribs 9, and a discharge space at the intersection of the data electrode 8, the scan electrode 4 and the sustain electrode 5 A discharge cell 12 is formed.

  As shown in FIG. 4, the electrode arrangement of this panel has a matrix configuration including M rows × N columns of discharge cells, and M rows of scan electrodes SCN <b> 1 to SCNM and sustain electrodes SUS <b> 1 to SUSM are arranged in the row direction. In the column direction, N columns of data electrodes D1 to DN are arranged.

By the way, the concept of wall charge becomes very important when considering the light emission of a plasma display device. A voltage higher than a certain voltage (Vf) cannot be applied between the electrodes of the panel, and if a voltage higher than Vf is applied between the electrodes, discharge starts. The wall charges are stored in each electrode by this discharge. The interelectrode voltage Vc is expressed by the externally applied voltage Va and the wall charge Vw,
The discharge starts when Vc = Va + Vw and Vc> Vf. There are two main types of discharge. One is a strong discharge that occurs when the externally applied voltage Va suddenly changes and the interelectrode voltage Vc exceeds Vf, neutralizing the potential state of the cell. As a result, wall charges accumulate on each electrode. The other is weak discharge that occurs when the externally applied voltage Va gradually changes and the interelectrode voltage Vc gradually exceeds Vf. In this weak discharge, the wall charges Vw accumulate while the interelectrode voltage Vc is kept at Vf.

  Here, an example of the driving method of the plasma display device (Patent Document 1) will be described with reference to FIG.

  In the initialization period 21, a weak discharge is generated by the positive gradually changing voltage waveform Vset 1 applied to the scan electrode 4 and the negative gradually changing voltage waveform Vset 2 applied to the sustain electrode 5. Negative wall charges are accumulated in the storage electrode 5, and positive wall charges are accumulated in the sustain electrode 5. Next, after the voltage of the sustain electrode 5 rises to the GND level, the scan electrode 4 is shifted to GND and the sustain electrode 5 is shifted to Vsus. At this time, a strong discharge is generated by the negative wall charge of the scan electrode 4 and the positive wall charge of the sustain electrode 5, and the positive wall charge is accumulated in the scan electrode 4 and the negative wall charge is accumulated in the sustain electrode 5. Discharge is terminated when the electric field strength of the inside becomes zero. Furthermore, the voltage applied to sustain electrode 5 rises to GND, and the voltage on scan electrode 4 rises to sustain voltage Vsus. A strong discharge is caused with the wall charges already stored, and the wall charges are inverted. In other words, negative wall charges opposite to the above are accumulated in scan electrode 4, and positive wall charges are accumulated in sustain electrode 5.

  Here, the voltage in the cell generates a strong discharge, and the wall charges are accumulated so as to neutralize this, and the discharge operation is terminated. Therefore, the data electrode 8 is also affected by the discharge, and the Vsus and GND levels Intermediate voltage wall charges accumulate. As a result, when the scan electrode 4 is then dropped to GND and no writing discharge occurs, the wall charge can be inverted again by raising the potential of the sustain electrode 5 to Vsus during the sustain period, and a sustain operation is possible. It becomes. That is, all the cells can be turned on by the initialization period 21.

  In the write period 22, all sustain electrodes 5 are held at GND, and a positive write pulse voltage (+ Vd) is applied to the predetermined data electrodes D1 to DN corresponding to the discharge cells to be displayed on the first row. When a negative scan pulse voltage (−Vsc) is applied to each of the scan electrodes SCN1, write discharge occurs at the intersections of the predetermined data electrodes D1 to DN and the scan electrode SCN1 in the first row. Next, a positive write pulse voltage (+ Vd) is applied to predetermined data electrodes D1 to DN corresponding to discharge cells to be displayed in the second row, and a negative scan pulse voltage (−Vsc) is applied to scan electrode SCN2 in the second row. ) Is applied to each, an address discharge occurs at the intersection of predetermined data electrodes D1 to DN and scan electrode SCN2 in the second row.

  The same operation as described above is sequentially performed, and finally, a positive write pulse voltage (+ Vd) is applied to predetermined data electrodes D1 to DN corresponding to discharge cells to be displayed in the Mth row, and the Mth row scanning electrode. When a negative scan pulse voltage (-Vsc) is applied to SCNM, an address discharge occurs at the intersection of predetermined data electrodes D1 to DN and Mth scan electrode SCNM. This discharge is caused by applying a negative voltage to the scan electrode having a negative wall charge and applying a positive voltage to the data electrode having a positive wall charge. After the discharge, the wall charge in the cell is almost equal. Disappear. Here, the scan pulse voltage Vsc is raised by the address voltage Vad from the GND level. This is because if Vad is 0, writing discharge is difficult to occur. Conversely, if Vad = Vscn, writing is performed by applying the scanning panel even when the writing operation is not performed. This is so that it can be performed smoothly.

  In the next sustain period 23, for the cells that have not performed the write operation, negative wall charges are accumulated in the scan electrode 4 and positive wall charges are accumulated in the sustain electrode 5, so that the scan electrode 4 is GND and the sustain electrode 5 is Vsus. As a result, the scan electrode 4 is positively charged and the sustain electrode 5 is negatively charged. Next, reverse wall charges are accumulated by applying reverse voltages to the respective voltages, and the discharge is continued by repeating this. At the end of the sustain period, the scan electrode 4 is set to Vsus, and the negative wall charges are accumulated to end the sustain period. This is the same as the initialization period. In the next sustain period, if no write discharge is generated, the discharge can be sustained. On the other hand, when the write discharge is performed, the wall charges are almost lost, so that the sustain operation cannot be performed.

For example, when one field as shown in FIG. 6 is divided into 8 subfields, the first subfield includes an initialization period 21, a writing period 22, and a sustain period 23, and the subsequent 2 to 8 subfields Consists of a writing period 22 and a sustaining period 23 only. All cells are lit in the initial initialization period, and the discharge in the sustain period is continued until the write discharge occurs, and the cells written in the write period are not lit thereafter. Therefore, as shown in FIG. 6, it is possible to express a total of nine gradations including the case where no sustain light emission is performed. In the figure, o is a subfield for sustaining light emission, and x is a subfield for writing discharge.
JP 2000-227778 A

  Here, the cell in the case where the write discharge is performed in the write period after completion of the initialization will be described. FIG. 7A shows the wall charge state after the completion of the initialization (point A in FIG. 5). As shown in the figure, negative wall charges are accumulated in the scan electrode 4 and positive wall charges are accumulated in the sustain electrode 5, and the wall charges are held until the writing period. When writing discharge is performed in the subsequent writing period (point B in FIG. 5), a pulse of Vad (V) is applied to the scanning electrode 4 and a writing pulse Vd (V) is applied to the data electrode 8 (FIG. 7B). . A wall charge is added to the voltage Vad (V) of the scan electrode 4 and the voltage Vd (V) of the data electrode 8, and the discharge discharge voltage is generated exceeding the discharge start voltage between the scan electrode 4 and the data electrode 8. As shown in FIG. 7 (c), wall charges are reformed in the cell. In the subsequent sustain period, sustain pulses having an amplitude of Vsus (V) are alternately applied to scan electrode 4 and sustain electrode 5, but when a Vsus (V) voltage is applied to scan electrode 4 (point C in FIG. 5). , The wall charge after writing is added to the Vsus voltage. When the amount of wall charges between the scan electrode 4 and the data electrode 8 after writing is sufficiently small, no discharge occurs when the sustain pulse is applied, but the Vad voltage is reduced to make the writing discharge smooth. When the Vd voltage is increased, the wall charge after the writing is increased, and when the sustain pulse is applied to the scan electrode 4 during the sustain period, the cell charge between the scan electrode 4 and the data electrode 8 is increased. The voltage exceeds the discharge start voltage, and discharge occurs (FIG. 7 (d)). When a discharge is generated between the scan electrode 4 and the data electrode 8 at the point C in FIG. 5, a discharge is generated between the scan electrode 4 and the sustain electrode 5, and a discharge is generated even in the subsequent sustain pulse. Even when the erasing discharge is performed during the writing period, a discharge occurs during the sustain period, which causes a display defect.

  The present invention solves such a problem, prevents a cell that has undergone a write discharge from being discharged during the sustain period, and eliminates display defects.

In order to achieve the above object, a driving method of a plasma display apparatus according to the present invention includes a scan electrode and a sustain electrode arranged in pairs, a data electrode arranged so as to cross the scan electrode and the sustain electrode, and a scan. In a driving method of a plasma display device in which discharge cells are formed at intersections of electrodes, sustain electrodes, and data electrodes, all of the first subfield groups formed by one field or a plurality of subfields having at least a writing period An initialization period in which the discharge cells are turned on, an address period in which the discharge cells are selectively subjected to write discharge for each subfield in the subfield group, and a discharge cell in which the write discharge is not performed maintaining the by the application of only sustain pulses to scan electrodes and sustain electrodes performing sustain electrodes And a while, during the sustain period, during the time between the first sustain pulse applied to the sustain electrode before the last sustain pulse is applied, the pulse voltage of the same polarity sustain the data electrodes is applied, and with the last sustain pulse in the sustain period is applied to the scan electrodes, the amplitude voltage of the sustain pulse applied to the last scan electrode, and smaller than the other of the amplitude voltage of the sustain pulse during the sustain period, the While the last sustain pulse is applied, the potential of the data electrode is set to GND .

As is clear from the above description, according to the present invention, during the sustain period, the first sustain pulse is applied to the sustain electrode and the last sustain pulse is applied until the last sustain pulse is applied to the data electrode. A polarity voltage is applied, and the last sustain pulse during the sustain period is applied to the scan electrode, and the amplitude voltage of the last sustain pulse applied to the scan electrode is the amplitude of the other sustain pulses during the sustain period. By setting the voltage smaller than the voltage, it is possible to prevent erroneous discharge in an unnecessary sustain period in a cell in which write discharge has been performed.

  Hereinafter, a method for driving a plasma display apparatus according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows the operation timing of the plasma display device according to the embodiment of the present invention. The initialization period 21 and the writing period 22 are the same as those shown in FIG.

  In the present invention, the sustain pulse of the amplitude voltage Vsus (V) is alternately applied to the sustain electrode and the scan electrode in the sustain period 23, and the last pulse of the sustain period after the first pulse of the sustain period is applied. 1 is applied, the voltage of Vda1 (V) is applied to the data electrode as indicated by P1 in FIG. 1, and the potential of the data electrode is set to GND during the last pulse of the sustain period. The amplitude voltage of the scan electrode is Vdk (V). The amplitude voltage Vbk (V) is smaller than the amplitude voltage Vsus (V) of other sustain pulses in the sustain period.

  As described above, wall charges are formed between the scan electrode and the data electrode in the cell in which the write discharge is performed in the write period. If the voltage applied to the scan electrode and the data electrode by the wall charge is the wall charge Vw (sc-dt), the scan electrode becomes Vsus (V) and the data electrode is GND in the conventional sustain period. And the voltage applied to the cell between the data electrodes is Vsus (V) + Vw (sc−dt) (V). When this voltage exceeds the discharge start voltage, erroneous discharge occurred during the sustain period.

  However, by applying the voltage Vda1 (V) to the data electrode when Vsus (V) is applied to the scan electrode, the voltage applied between the scan electrode and the data electrode is Vsus (V) −Vdal (V) + Vw ( sc-dt) (V), and the potential difference between the scan electrode and the data electrode is smaller than in the prior art, so that erroneous discharge is less likely to occur.

  In all sustain pulses, if the potential of the data electrode is set to Vda1 (V), a cell in which write discharge is performed does not cause a false discharge phenomenon, but a cell in which no write discharge is performed (during the sustain period). In the cell which performs the sustain discharge at the same time, since the potential of the data electrode is increased, the wall charges cannot be sufficiently stored on the data side after the end of the sustain period. As a result, problems such as subsequent writing discharge not being performed normally occur. In the present invention, in the final pulse of the sustain period, the potential of the data electrode is set to GND, and the amplitude voltage of the final pulse is set to Vbk (V). The in-cell voltage between the electrodes is Vbk (V) + Vw (sc−dt) (V), and Vbk (V) <Vsus (V), so that an erroneous discharge is unlikely to occur between the scan electrode and the data electrode. Further, it becomes possible to store wall charges between the scan electrode and the data electrode with the last pulse of the sustain period even for a cell that does not perform the write discharge, and the subsequent write operation can be performed smoothly.

  Here, the amplitude voltage Vbk (V) of the final pulse needs to be a voltage value sufficient to sustain the sustain discharge while Vbk (V) <Vsus (V). Specifically, Vbk (V) is Vsus (V) −10V or less, and is desirably set in a range of Vsus (V) −30V or more. At this time, the pulse width (Tbk) of the last sustain pulse is set wider than the sustain pulse width (Tsus) of the other sustain pulses in the sustain period, so that even in the case where the amplitude voltage of the sustain pulse is small, A cell that has not been written can normally perform a sustain discharge.

Thus, in order to reduce erroneous discharge during the sustain period, the potential of the data electrode may be increased when the sustain pulse of the amplitude voltage Vsus (V) is applied to the scan electrode. . However, if the potential of the data electrode is changed in synchronization with the sustain pulse of the scan electrode, a considerable amount of reactive power is generated. In the present invention, during the sustain period, a voltage having the same polarity as the sustain pulse is applied to the data electrode after the first pulse is applied to the sustain electrode and before the last pulse is applied. With this configuration, it is possible to suppress not only the erroneous discharge between the scan electrode and the data electrode described above but also the erroneous discharge phenomenon between the sustain electrode and the scan electrode. FIG. 2 shows an operation timing chart of the plasma display device according to another embodiment of the present invention. 1 differs from FIG. 1 in that the voltage Vda1 (V) applied to the data electrode during the sustain period is the same as the voltage Vd (V) applied to the data electrode during the write period, the initialization period, and the write period. The wall charge adjustment period 24 is provided between the sustain period and the writing period during the period. By making the voltage Vda1 (V) applied to the data electrode during the sustain period the same as the voltage Vd (V) applied to the data electrode during the write period, the effect obtained in the above embodiment is hardly impaired. The power supply and driving circuit used for driving the data electrode can be simplified, and the cost can be reduced. In addition, by applying a driving waveform having a wall charge adjustment period between the initialization period and the write period, and between the sustain period and the write period, the wall charge state in the panel surface is adjusted by the wall charge adjustment period, The cell-to-cell variation can be reduced, and the write voltage Vd (V) can be lowered.

FIG. 4 is an operation timing chart of the method for driving the plasma display apparatus according to the embodiment of the present invention. Operation Timing Diagram in Driving Method of Plasma Display Device According to Other Embodiment of the Present Invention Perspective view showing a plasma display panel with a part cut away Explanatory drawing showing the electrode arrangement of the plasma display panel Operation timing chart of conventional plasma display device Explanatory drawing showing a conventional drive sequence Cell inner wall charge distribution diagram showing conventional problems

Explanation of symbols

1, 6 Substrate 4 Scan electrode 5 Sustain electrode 8 Data electrode 12 Discharge cell 21 Initialization period 22 Write period 23 Sustain period

Claims (1)

A scan electrode and a sustain electrode are arranged in a pair, a data electrode is arranged to intersect the scan electrode and the sustain electrode, and a discharge cell is formed at an intersection of the scan electrode, the sustain electrode and the data electrode. An initializing period in which all discharge cells are turned on at the beginning of a subfield group constituted by a plurality of subfields having one field or at least a writing period, and a subfield group, The sustain pulse is applied only to the scan electrode and the sustain electrode of the discharge cell where the discharge discharge is not performed by selectively performing the discharge discharge to the discharge cell for each subfield and the discharge discharge is not performed. A sustain period for performing the sustain electrode, and during the sustain period, the sustain electrode is initially maintained Between Luz is applied before the last sustain pulse is applied, applying a voltage of the sustain pulse having the same polarity to the data electrodes, and applying a last sustain pulse in the sustain period to the scan electrodes In addition, the amplitude voltage of the sustain pulse last applied to the scan electrode is smaller than the amplitude voltage of the other sustain pulses during the sustain period, and the potential of the data electrode is applied during the last sustain pulse application. A method for driving a plasma display device, characterized in that GND is used.

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