JP3452023B2 - Driving method of plasma display panel - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel (PD) used for a personal computer, a display output of a workstation, a wall-mounted television, etc., as a flat display whose area can be easily increased.
P).

[0002]

2. Description of the Related Art PDPs are classified into a DC type in which an electrode is exposed to a discharge gas and an AC type in which a PDP is not directly exposed to a discharge gas because the electrode is covered with a dielectric material. is there. Further, the AC type includes a memory operation type that uses a memory function by the charge storage action of the dielectric and a refresh operation type that does not use the memory function.

FIG. 7 shows a general memory operation type AC-PD.
A sectional view of P is shown. As shown in this figure, the PDP has the following structure formed in a space sandwiched between a front substrate 10 made of glass and a rear substrate 11 also made of glass. On the front substrate 10, a plurality of scan electrodes Si and a plurality of common electrodes C that extend in the depth direction of the paper at a predetermined interval are provided.
i is formed. The scan electrode Si and the common electrode Ci are covered with a dielectric layer 15a, and a protective layer 16 made of MgO or the like for protecting the dielectric layer 15a from discharge is formed on the dielectric layer 15a.

On the rear substrate 11, a plurality of data electrodes Dj extending in the left-right direction of the paper are formed so as to be orthogonal to the scanning electrodes Si and the common electrodes Ci. Data electrode D
j is covered with the dielectric layer 15b, and on the dielectric layer 15b,
A phosphor 18 is applied to convert the ultraviolet rays generated by the discharge into visible light. A color display PDP can be obtained by separately applying the phosphor 18 to each pixel, for example, red, green, and blue (RGB), which are the three primary colors of light.

A partition wall (not shown) is formed between the dielectric layer 15a on the front substrate 10 and the dielectric layer 15b on the rear substrate 11 to secure the discharge space 20 and partition the pixels. . He, Ne, A in the discharge space 20
A gas in which r, Kr, Xe, N2, O2, CO2, etc. are mixed is filled as a discharge gas.

Next, FIG. 8 shows a plan view of an electrode structure in a color display PDP in which the phosphor 18 shown in FIG. 7 is separately applied to each of the three primary colors of light, red green blue (RGB), for each pixel. In FIG. 8, in the electrode structure of the color PDP, m scanning electrodes Si (i = 1, 2, ..., M) are formed in the row direction, and n data electrodes Dj (j = 1, 2, ...
n) are formed in the column direction, and one pixel is formed at the intersection. The common electrode Ci is paired with the scan electrode Si, is formed in the row direction, and is parallel to each other.

Next, the above-mentioned memory operation type AC-PDP
An example of the conventional driving method will be described with reference to FIG. FIG. 9 is a timing chart showing a drive voltage waveform applied to each electrode of the color PDP. In this figure, first, an erase pulse 21 is applied to all the scan electrodes S1 to Sm,
The discharge state of the pixels emitting light by the sustain discharge before the time shown in the figure is stopped, and all the pixels are put into the erased state. The discharge operation by this pulse is called sustain discharge erase. Here, erasing means an operation of reducing or eliminating wall charges described later.

Next, the common electrodes C1 to Cm are provided with a first negative electrode.
The second preliminary discharge pulse 22b having the positive polarity is simultaneously applied to the scan electrodes S1 to Sm. As a result, the common electrodes C1 to Cm and the scan electrode S
A potential difference exceeding the discharge start voltage is applied between 1 and Sm to forcibly discharge all pixels. Then, the scan electrode S1
The preliminary discharge erasing pulse 23 is applied to Sm to erase the discharge of all pixels. The discharge operation by the preliminary discharge pulse is called preliminary discharge, and the discharge operation by the preliminary discharge erase pulse is called preliminary discharge erase. Then, the pre-discharge and the erasing of the pre-discharge facilitate the later writing discharge.

After the preliminary discharge and the preliminary discharge are erased, the scanning pulse 24 is applied to the scanning electrodes S1 to Sm at different timings, and the data electrodes D1 to Dn are displayed in accordance with the display information in accordance with the timing of applying the scanning pulse 24. And the data pulse 27 is applied. The diagonal line of the data pulse 27 indicates that the presence or absence of the data pulse 27 is determined according to the presence or absence of display information for the corresponding pixel. In the pixel to which the data pulse 27 is applied when the scan pulse 24 is applied, discharge is generated in the discharge space between the scan electrodes S1 to Sm and the data electrodes D1 to Dn. On the other hand, scan pulse 2
When 4 is applied, no discharge occurs if the data pulse 27 is not applied. Here, since display information is written in each pixel depending on the presence / absence of this discharge, this is called write discharge.

In the pixel where the writing discharge occurs, positive charges called wall charges are accumulated in the dielectric layer on the scan electrodes S1 to Sm. At this time, negative wall charges are accumulated in the dielectric layers on the data electrodes D1 to Dn. By superimposing the positive potential due to the positive wall charges formed on the dielectric layer 15a on the scan electrodes S1 to Sm and the negative sustaining first sustain pulse 25 applied to the common electrodes C1 to Cm, The first discharge occurs. When the first discharge occurs, the common electrodes C1 to C
positive wall charges on the dielectric layer 15a on the scanning electrode S
Negative wall charges are accumulated in the dielectric layer 15a above 1 to Sm. The second sustain pulse 26 applied to the scan electrodes S1 to Sm is superimposed on the potential difference due to the wall charges, and the second discharge is generated. In this way, the potential difference due to the wall charges formed by the n-th discharge and the sustain pulse of the (n + 1) -th discharge are superimposed to maintain the discharge. Therefore, this discharge operation is called sustain discharge. The brightness is controlled by the number of sustain discharges.

If the voltages of the sustain pulse 25 and the sustain pulse 26 are adjusted in advance so that the discharge does not occur only by applying these pulses, the first sustain is applied to the pixel in which the writing discharge does not occur. Since there is no potential due to wall charges before the pulse 25 is applied, the first sustain pulse 25
The first sustaining discharge does not occur even if is applied, and therefore, the sustaining discharge thereafter does not occur.

Next, another driving method of the conventional memory operation type AC-PDP will be described with reference to FIG. Figure 1
0 is a timing chart showing a drive voltage waveform applied to each electrode of the color PDP of FIG. 8, and the waveform of FIG. 9 is a waveform to the common electrode 13 during the period when the scan pulse 24 and the data pulse 27 are applied. The difference is that the sub-scanning pulse 28 of positive polarity is applied. Since the operations of the preliminary discharge and the sustain discharge are the same as those in FIG. 9, the description thereof will be omitted, and the write discharge will be described below.

With respect to this writing discharge, for example, Japanese Patent Laid-Open No. Hei 6
No. 289811, immediately after a counter discharge is generated between the scan electrodes S1 to Si and the data electrodes D1 to Dn due to the superposition of the scan pulse 24 and the data pulse 27, the scan electrode S1 is caused by the potential difference created by the scan pulse 24. It is disclosed that the transition from the write discharge to the sustain discharge is ensured by the occurrence of the surface discharge between Si and the common electrodes C1 to Ci.

Further, in Japanese Unexamined Patent Publication No. 6-289811, when the scanning pulse 24 is applied, the sub-scanning pulse 28 having a bias potential having a polarity opposite to that of the scanning pulse 24 is applied to the common electrodes C1 to Ci. Of the scan electrode S1
~ Si and the common electrode C1 ~ Ci to increase the potential difference,
After the occurrence of the opposed discharge, the scan electrodes S1 to Si and the common electrode C1 to
A technique for facilitating the occurrence of surface discharge between Ci is proposed.

As a result, due to the superposition of the scanning pulse 24 and the data pulse 27, immediately after the counter discharge is generated between the scanning electrodes S1 to Si and the data electrodes D1 to Di, the scanning pulse 24 and the sub scanning pulse 28 are superposed. , Scan electrode S1
Surface discharge occurs between .about.Si and the common electrodes C1 to Ci.
Finally, positive wall charges are applied to the dielectric layer 15a on the scan electrodes S1 to Si and the dielectric layer 15 on the data electrodes D1 to Di.
Negative wall charges are accumulated in b and negative wall charges are accumulated in the dielectric layer 15a on the common electrode 13.

Thereafter, a positive potential due to the positive wall charges formed on the dielectric layer 15a on the scan electrodes S1 to Si and a negative potential due to the negative wall charges formed on the dielectric layer 15a on the common electrodes C1 to Ci. By superimposing the negative first sustain pulse 25 applied to the common electrodes C1 to Ci on the potential, the first discharge is generated, and the sustain discharge is continued in the same manner as described with reference to FIG. To do.

In the drive voltage waveforms of FIGS. 9 and 10 described above, the erase pulse 21 and the preliminary discharge pulses 22a, 2
2b, the period for applying the preliminary discharge erase pulse 23 is the preliminary discharge period, the period for applying the scan pulse 24, the data pulse 27, and the sub-scan pulse 28 is the scan period, the sustain pulse 25,
The period in which 26 is applied will be referred to as the sustain period.
In addition, combining the preliminary discharge period, scanning period, and sustain period,
Define as a subfield.

As described above, in the conventional writing discharge, the scanning pulse and the data pulse are superposed and a potential difference larger than the counter discharge starting voltage is applied between the scan electrode and the data electrode to generate the counter discharge. When a counter discharge occurs,
Since a large amount of charged particles are generated in the discharge space and the surface discharge starting voltage between the scan electrode and the common electrode is lowered, the potential difference between the superposed scanning pulse and the sub-scanning pulse exceeds the surface discharge starting voltage. Following the counter discharge, a surface discharge is generated between the scan electrode and the common electrode. When the data pulse is not applied, the opposing discharge does not occur, so the surface discharge starting voltage does not decrease, and as a result, the surface discharge does not occur.

The above-mentioned write discharge will be specifically described with reference to FIG. FIG. 2 is a characteristic diagram showing a relationship between a potential difference between the scan electrode and the data electrode (potential difference between S and D) and a surface discharge start voltage between the scan electrode and the common electrode (discharge start voltage between S and C). . As shown in this figure, in the conventional writing discharge, it was necessary to set the potential difference between the scan electrode and the data electrode to be equal to or higher than the counter discharge starting voltage when the data pulse was selectively applied. For example, the scan pulse voltage is 170 V, the data pulse voltage is 60 V, the sub-scan pulse voltage is 20 V, and SD is applied when the data pulse is selectively applied.
By setting the electric potential difference between 170V + 60V = 230V,
The opposite discharge starting voltage of 180 V is exceeded to generate the opposite discharge. As a result, the surface discharge starting voltage is lowered and the surface discharge is generated (see area C in FIG. 2). Then, in the pixel where the counter discharge and the surface discharge are generated, the sustain discharge is generated, and the pixel is in a light emitting state (“display”).

On the other hand, when the data pulse is not applied, the S-D potential difference is lower than the counter discharge inception voltage.
Opposing discharge does not occur. In this case, since the surface discharge inception voltage does not decrease due to the occurrence of the opposed discharge, the surface discharge does not occur. In such a case, the S-C discharge start voltage is recognized to be constant. In fact, the S-C discharge start voltage is constant in the range below and close to the counter discharge start voltage (see the region B in FIG. 2).

[0021]

As described above, in the conventional PDP driving method, the scan pulse applied to the scan electrode and the data pulse applied to the data electrode are superposed.
The potential difference between S and D is made equal to or higher than the opposite discharge start voltage, and the opposite discharge is generated to determine the display pixel. Therefore, due to the superposition of the scan pulse and the data pulse, a large potential difference is required to generate counter discharge. However, since the scan pulse and the data pulse are output from the scan driver and the data driver, respectively, which are integrated into an IC, unless the withstand voltage of these ICs is increased, the peak value is large enough to generate a potential difference that causes counter discharge. The scan pulse and the data pulse cannot be output. As a result, there is a drawback in that it is necessary to use a scan driver IC and a data driver IC that have a high breakdown voltage but are expensive.

Further, since the peak values of the scanning pulse and the data pulse are large, these pulses are used as a capacitive load PDP.
When applied to the capacitor, a large amount of electric power is lost in charging and discharging the capacity. Here, the charge / discharge loss when the peak value V is charged / discharged in the capacity C is obtained by (capacity C) × (peak value V) ² . As described above, the crest value squares to contribute to the loss. Therefore, there is a problem that the charging and discharging loss becomes very large due to the large crest value.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method of driving a plasma display panel in which a scan pulse voltage is reduced, and a scan driver having a low withstand voltage and a low cost can be used. And

[0024]

In order to achieve the above object, the present invention provides two glass substrates, at least one of which is transparent, facing each other with a predetermined gap therebetween, and a plurality of scans on one substrate. An electrode, a plurality of common electrodes that are paired with the scanning electrode and are parallel to each other, and a plurality of data electrodes that are orthogonal to the scanning electrode on the other substrate, and a discharge gas is enclosed in the space, Display pixel selection is performed by applying a time-division scan pulse to the scan electrode and selectively applying a data pulse to the data electrode in synchronization with the scan pulse, and maintaining only the display pixel after the display pixel selection. In the driving method of the plasma display panel for discharging,
When the scan pulse is applied, a sub-scan pulse having a polarity opposite to that of the scan pulse is applied to the common electrode, and a potential difference between the scan electrode and the data electrode is selectively applied by the data pulse, It is characterized in that display pixels are selected by selectively changing the discharge start voltage within a range not exceeding the discharge start voltage and selectively generating surface discharge between the scan electrode and the common electrode.

In the above invention, it is preferable that the scanning pulse has a negative polarity and the sub-scanning pulse has a positive polarity. Further, in the above-mentioned invention, the sub-scanning pulse is applied over almost the entire area of the period for selecting the display pixel.
The feature is that the voltage is always applied.

In the above invention, the crest value of the sub-scanning pulse is larger than the crest value of the scanning pulse. As described above, according to the present invention, the scanning pulse has a negative polarity, and the sub-scanning pulse has a positive polarity, and the sub-scanning pulse is constantly applied in almost the entire period for performing the display pixel selection, It is preferable that the peak value of the sub-scanning pulse is larger than the peak value of the scanning pulse.

As described above, in the writing discharge of the present invention, the counter potential is selectively changed by the superposition of the scanning pulse and the data pulse according to the display information, and the surface discharge is selectively generated by the superposition of the scanning pulse and the sub-scanning pulse. Let On the other hand, in the conventional write discharge, counter discharge is selectively generated by superimposing a scan pulse and a data pulse according to display information, and a surface discharge is generated by superimposing a scan pulse and a sub-scan pulse using this counter discharge as a trigger. Let As described above, the present invention differs from the conventional method in which the opposed discharge is used as a trigger, in that the surface discharge is generated by the change in the potential difference (SD potential difference) between the scan electrode and the data electrode. Then, by performing the address discharge in this way, it is not necessary to generate the counter discharge, so that the scan pulse voltage can be made smaller than in the conventional case.

As a result, an IC having a low withstand voltage and a low cost can be used as a scan driver which outputs a scan pulse. Further, since the peak value of the scan pulse becomes small, the charge / discharge power loss when the scan pulse is applied to the PDP, which is a capacitive load, becomes small, the power consumption of the scan driver is also reduced, and the heat radiation measure is also eased. You can Further, since the current corresponding to the opposite discharge does not flow, the power consumption of the data driver can be reduced and the heat dissipation measures of the data driver can be relaxed.

[0029]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, the PDP to be driven is a memory operation type AC-PDP as shown in FIGS. 7 and 8.

First, a drive circuit for driving a PDP having the configuration shown in FIGS. 7 and 8 will be described with reference to FIG. FIG. 5 is a diagram showing a drive circuit of a PDP and electrodes connected to the drive circuit according to an embodiment of the present invention.
In this figure, reference numeral 1 is a sustain driver that outputs a sustain pulse for generating sustain discharge to all the common electrodes C1 to Cm. Reference numeral 3 is a preliminary discharge pulse driver that outputs a preliminary discharge pulse to all the common electrodes C1 to Cm. Reference numeral 2 is a sustain driver that outputs a sustain pulse for generating sustain discharge to the scan driver 4, and reference numeral 6
Is an erase driver that outputs an erase pulse to the scan driver 4.

The scan driver 4 outputs scan pulses to the scan electrodes S1 to Sm at different timings, and the sustain pulse output by the sustain driver 2 and the erase pulse output by the erase driver 6 are output to all scan electrodes S1 to Sm.
output to m. Reference numeral 5 is the timing at which the data pulse is output as the scanning pulse, and according to the pixel information to be displayed,
The data driver 5 outputs to the data electrodes D1 to Dn.

In addition to this, a driver for outputting the pre-discharge erasing pulse and the sub-scanning pulse is also necessary, but it is omitted for simplification. The scan pulse is applied to the individual scan electrodes S1 to Sm, and the data pulse is applied to the individual data electrodes D1 to Dn. Therefore, the scan driver 4 and the data driver 5 need to have the same number of outputs as the total number of the scan electrodes S1 to Sm and the data electrodes D1 to Dn. Therefore, generally, the scan driver 4 and the data driver 5 are used in an IC integrated state so as to have a large number of outputs. on the other hand,
Since the sustain pulse or the like may be uniformly applied to all the common electrodes or all the scan electrodes, only one output from the sustain driver or the like is required, and it is not necessary to form an IC.

Next, a gradation display method in the PDP will be described with reference to FIG. One field, which is a period (for example, 1/60 seconds) for displaying one screen, is divided into a plurality of subfields (for example, 4 subfields). The individual subfields have the configuration shown in FIG. 9 or FIG. 10, and the ON / OFF of the display of each subfield is controlled independently of the other subfields. In addition, the length of the sustain period, in other words, the number of sustain pulses is different in each subfield, and thus the brightness is also different.

In the four-subfield division shown in FIG. 6, if the luminance ratio when each subfield is made to emit light independently is adjusted to be 1: 2: 4: 8, the four subfields are divided into four subfields. By combining the display ON / OFF of, the luminance display of 16 steps from the luminance ratio 0 in the case of not selecting all the subfields to the luminance ratio 15 in the case of selecting all the subfields is possible. Generally, one field is divided into n subfields, and the luminance ratio of each subfield is 1 (= 20): 2 (= 21): ...: 2n−
When set to 2: 2n-1, 2n gradation display is possible.

Next, the drive voltage waveform applied to each electrode of the PDP will be described with reference to FIG. As shown in this figure, in this embodiment, the peak value of the positive sub-scanning pulse 28a applied to the common electrodes C1 to Cm is set to be much larger than that in the conventional case (see the sub-scanning pulse 28 in FIG. 10). On the other hand, the peak value of the scanning pulse 24a is set to be much smaller than that in the conventional case (see the scanning pulse 24 in FIGS. 9 and 10). The peak values of the sub-scanning pulse 28a and the scanning pulse 24a are determined by the potential difference between the scanning electrode and the data electrode (hereinafter, SD) when the data pulse is selectively applied.
Inter-electrode potential difference), that is, the value obtained by superimposing the scanning pulse 24a and the data pulse 27 is smaller than the counter discharge inception voltage, and at this time, the potential difference between the scanning electrode and the common electrode (hereinafter, between S and C). Potential difference), that is, scanning pulse 2
The value obtained by superimposing 4a and the sub-scanning pulse 28a is set to be a value larger than the surface discharge start voltage (SC discharge start voltage) between the scan electrode and the common electrode. As a result, when the data pulse is selectively applied, it is possible to generate only the surface discharge without generating the counter discharge.

The write selection operation in this embodiment will be described below with reference to FIG. For example, when the scan pulse voltage is 40V, the data pulse voltage is 60V, and the sub-scan pulse voltage is 180V, S- is applied when the data pulse is applied.
The potential difference between D becomes 60V + 40V = 100V, and does not reach the counter discharge starting voltage 180V. Therefore, the opposed discharge does not occur. On the other hand, the S-C discharge start voltage corresponding to the S-D potential difference of 100 V is 205 V from FIG.
Since the potential difference between −C is 40V + 180V = 220V, it exceeds the discharge start voltage between S−C. Therefore, surface discharge occurs. In the pixel where the surface discharge is generated, the sustain discharge is continuously generated, and the pixel is in the light emitting state.

On the other hand, when no data pulse is applied, S-
The potential difference between D becomes 40 V of the scanning pulse voltage. Since the S-C discharge start voltage at this time is 250 V from FIG. 2, it is larger than the S-C potential difference of 220 V, so that no surface discharge occurs. As described above, in the present embodiment, the pixel to which the data pulse is applied is “display”, and the pixel to which the data pulse is not applied is “non-display”.

As described above, in the present invention, in the region where the S-D potential difference is considerably lower than the counter discharge inception voltage, that is, in the region A in FIG. 2, the S-C discharge inception voltage is S-D.
Focusing on the dependence on the inter-potential difference, we have succeeded in selectively generating a surface discharge without generating a counter discharge.

As a result, only the surface discharge can be generated without generating the counter discharge, so that the scanning pulse voltage can be set smaller than that of the conventional one. As a result, an IC having a low withstand voltage can be used as a scan driver that outputs a scan pulse, so that the cost can be reduced. Further, since the peak value of the scan pulse becomes small, the charge / discharge power loss when the scan pulse is applied to the PDP, which is a capacitive load, becomes small, the power consumption of the scan driver is also reduced, and the heat radiation measure is also eased. You can Further, since the current corresponding to the opposite discharge does not flow, the power consumption of the data driver can be reduced and the heat dissipation measures of the data driver can be eased.

Further, the sub-scanning pulse voltage needs to be set to a value higher than that of the conventional one, but a pulse such as the sub-scanning pulse which is simultaneously applied to all common electrodes is compatible with a large power without using an IC. The circuit is composed of a plurality of FETs. Since this high-power circuit has a larger withstand voltage than an IC, problems such as breakdown voltage are solved.
In addition, it is possible that a very small number of circuit elements (diodes, FETs, etc.) in a high-power compatible circuit may need to be replaced with high-voltage ones.
It is technically and cost-effectively simple compared to the high breakdown voltage of IC.

Regarding the second embodiment of the present invention, the PDP
This will be described with reference to FIG. 3, which shows a drive voltage waveform applied to each of the electrodes. The types of drive pulses other than the scanning period are shown in FIG. 9 and 1 showing the drive voltage waveform applied to each electrode of the conventional PDP.
The description is omitted because it is the same as 0.

In the second embodiment, in the scanning period, the sub-scanning pulse 28b of positive polarity and the scanning pulse 24b of negative polarity are used.
And the negative data pulse 27a are applied to the respective electrodes. The peak values of the sub-scanning pulse 28b and the scanning pulse 24b are SD when the data pulse 27a is not applied.
Potential difference, that is, the value of the scanning pulse 24b is smaller than the counter discharge starting voltage, and the data pulse 27a
When S is selectively applied, the S-C potential difference is set to a value smaller than the S-C discharge start voltage.

The write selection operation in this embodiment will be described below with reference to FIG. FIG. 4 is a characteristic diagram showing the relationship between the S-D potential difference and the S-C discharge start voltage in the second embodiment. In the present embodiment, since both the scan pulse 24b and the data pulse 27a have a negative polarity, in the pixel to which the data pulse 27a is not applied, S-
The potential difference between D is large, and the potential difference between S and D is small in the pixel to which the data pulse 27a is selectively applied.

Therefore, as the potential difference between S and D increases, S
By utilizing the region (region A in FIG. 4) in which the -C discharge start voltage decreases, when the data pulse 27a is not applied,
When the S-C potential difference exceeds the S-C discharge start voltage and the data pulse 27a is applied, the S-C potential difference becomes S.
The peak values of the sub-scanning pulse 28b and the scanning pulse 24b are set so as to be smaller than the -C discharge start voltage. As a result, the surface discharge can be selectively generated for each pixel depending on the presence or absence of the data pulse 27a, and this can be used as the write discharge.

In the write discharge according to the embodiment of the present invention, for example, when the scan pulse voltage is 100V, the data pulse voltage is 60V, and the sub-scan pulse voltage is 120V, the potential difference between S and D is the scan pulse when the data pulse is not applied. The voltage is 100 V, and the counter discharge start voltage is 180
Does not reach V. Therefore, the opposite discharge does not occur. on the other hand,
The S-C discharge start voltage corresponding to the S-D potential difference of 100 V is 205 V from FIG. 4, and the S-C potential difference is 100 V.
Since V + 120V = 220V, the S-C discharge start voltage 205V is exceeded. Therefore, surface discharge occurs.
In the pixel where the surface discharge is generated, the sustain discharge is continuously generated, and the pixel is in the light emitting state.

On the other hand, when the data pulse is selectively applied,
The potential difference between SD is 100V-60V = 40V. Since the S-C discharge start voltage at this time is 250 V from FIG. 4, it is larger than the S-C potential 220 V, so that the surface discharge does not occur. As described above, in this embodiment, the pixel to which the data pulse is applied is “non-display”, and the pixel to which the data pulse is not applied is “display”.

In this embodiment as well, the scan pulse voltage can be smaller than in the prior art, so the same effects as in the first embodiment of the invention can be obtained, such as reduction in withstand voltage of the scan driver and reduction in power consumption. it can.

The third embodiment of the present invention will be described with reference to FIG. 1 again showing the driving voltage waveform applied to each electrode of the PDP. In order to obtain the effect of the first or second embodiment, as described above, "the value of the S-D potential difference is smaller than the counter discharge start voltage (or the scan pulse 24
The potential of b is smaller than the counter discharge starting voltage), and the potential difference between S and C when the data pulse is applied, that is, the value obtained by superimposing the scanning pulse 24a and the sub-scanning pulse 28a exceeds the surface discharge starting voltage. Value (or a potential difference between S and C when no data pulse is applied, that is, a value at which a value obtained by superimposing the scanning pulse 24b and the sub-scanning pulse 28b is larger than the surface discharge starting voltage) is required. .

In order to satisfy this condition, in this embodiment, the sub-scanning pulse has a positive polarity and the scanning pulse has a negative polarity. In order to easily generate the surface discharge between the scanning electrode and the common electrode, it is preferable that the sub-scanning pulse and the scanning pulse have opposite polarities. However, if the sub-scanning pulse has a negative polarity and the scanning pulse has a positive polarity, a counter discharge is generated between the common electrode and the data electrode when the sub-scanning pulse is applied, which hinders subsequent driving. This is due to the action of the protective layer made of MgO or the like that further covers the dielectric layer that covers the common electrode.

In general, the protective layer is 2 by ion bombardment.
It is made of a material that easily emits secondary electrons. Therefore, in the discharge mode in which the electrode covered with the protective layer serves as the cathode, the positive ions of the rare gas are collected in the protective layer and a large amount of secondary electrons are emitted, so that discharge easily occurs. On the contrary, in the discharge mode in which the electrode covered with the protective layer serves as an anode, it is electrons, not ions, that collect in the protective layer, and the effect of secondary electron emission cannot be obtained, so that discharge is unlikely to occur. In surface discharge that occurs between the common electrode and the scanning electrode, both electrodes have a protective layer on top of them, so whichever electrode becomes the anode, the other electrode becomes the cathode and Since the protective layer is effectively used, discharge is always likely to occur.

However, in the counter discharge generated between the common electrode and the data electrode, the secondary electron emission effect of the protective layer can be utilized only when the common electrode serves as the cathode. Therefore, when a negative sub-scanning pulse is applied to the common electrode, the common electrode serves as a cathode and the data electrode serves as an anode, and discharge easily occurs, which has an adverse effect (inhibition of driving) in the configuration of the present invention. More specifically, the adverse effect state will be described. When a negative sub-scanning pulse is used, even if an attempt is made to increase the potential difference between the surface electrodes between the common electrode and the scanning electrode, a sub-scanning pulse of a certain magnitude or more is generated. When applied, a counter discharge is generated between the data electrode and the common electrode, and a desired potential difference between the surface electrodes cannot be obtained.

On the other hand, when the sub-scanning pulse having the positive polarity is used, the common electrode side having the protective layer serves as the anode, so that the opposing discharge generated by the sub-scanning pulse is hard to occur and a desired potential difference between the surface electrodes is obtained. The sub-scanning pulse voltage can be increased.

In the above description, the sub-scanning pulse is applied in a constant manner over the entire scanning period.
Since the sub-scanning pulse may be applied in response to the application of the scan pulse, even if the sub-scanning pulse is divided and applied to a plurality of sub-scanning pulses, the effect of the invention can be obtained similarly.

Further, the voltage value of each pulse used in the description is an example of the measurement result, and when the opposite discharge starting voltage and the surface discharge starting voltage characteristics are different, an appropriate voltage value having the configuration of the present invention is obtained. It is natural to say Here, the upper limit of the voltage of the sub-scanning pulse is a value at which discharge is generated only by applying the sub-scanning pulse in the pixel row to which the scanning pulse is not applied. This discharge is either a surface discharge serving as a counter scanning electrode or a counter discharge serving as a data electrode.
By making the sub-scanning pulse have a positive polarity as in the third embodiment of the invention, counter discharge is less likely to occur than in the case of a negative polarity, but there is an upper limit. Further, in order to reduce the scan pulse voltage, it is preferable to make the sub-scanning pulse voltage (peak value) larger than the scan pulse voltage (peak value). As a result, most of the potential difference between the surface electrodes required to have the configuration of the present invention is obtained by the sub-scanning pulse voltage.

[0055]

As described above, according to the present invention, when the scanning pulse is applied, the sub-scanning pulse having the opposite polarity to the scanning pulse is applied to the common electrode, and the selective application of the data pulse causes the scanning electrode and the data electrode to be selectively applied. A display pixel is selected by selectively changing the potential difference between them within a range not exceeding the discharge start voltage and selectively generating a surface discharge between the scan electrode and the common electrode.

As described above, the scanning pulse voltage can be reduced by changing the counter potential difference and selectively generating the surface discharge within the range where the counter discharge is not generated. Therefore, the scan for outputting the scan pulse is performed. An effect that an IC with low withstand voltage and low cost can be used for the driver is obtained.

Further, according to the invention of claim 4, since the peak value of the sub-scanning pulse is larger than the peak value of the scanning pulse, the peak value of the scanning pulse becomes small and the scanning pulse is a capacitive load PDP. The effect of reducing the power loss of charging / discharging at the time of applying to, the power consumption of the scan driver, and the measure of heat dissipation can be obtained. Further, since the current corresponding to the opposite discharge does not flow, the power consumption of the data driver is reduced, and the heat dissipation measures of the data driver can be relaxed.

[Brief description of drawings]

FIG. 1 is a P diagram for explaining a first embodiment of the invention.
It is an example of the drive voltage waveform applied to each electrode of DP.

FIG. 2 is a characteristic diagram showing the relationship between the potential difference between the scan electrode and the data electrode and the discharge start voltage between the scan electrode and the common electrode, for explaining the first embodiment of the invention.

FIG. 3 is a P diagram for explaining a second embodiment of the invention.
It is an example of the drive voltage waveform applied to each electrode of DP.

FIG. 4 is a characteristic diagram showing the relationship between the potential difference between the scan electrode and the data electrode and the discharge start voltage between the scan electrode and the common electrode, for explaining the second embodiment of the invention.

FIG. 5 is a structural diagram showing a relationship between a general PDP drive driver and connected electrodes.

FIG. 6 is a timing chart explaining a gradation display method of the plasma display panel.

FIG. 7 is an example of a structural diagram showing a cross section of a general PDP.

FIG. 8 is a plan view schematically showing an electrode arrangement of a general PDP.

FIG. 9 is an example of a drive voltage waveform applied to each electrode of a conventional PDP.

FIG. 10 is another example of the drive voltage waveform applied to each electrode of the conventional PDP.

[Explanation of symbols]

4 Scan driver 5 Data driver 20 discharge space 24, 24a, 24b scanning pulse 27,27a Data pulse 28, 28a, 28b Sub-scanning pulse

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI G09G 3/20 624 H04N 5/66 101B H04N 5/66 101 G09G 3/28 H (58) Fields investigated (Int.Cl. ⁷ , DB name) G09G 3/28 G09G 3/20 611 G09G 3/20 621 G09G 3/20 622 G09G 3/20 623 G09G 3/20 624 H04N 5/66 101

Claims (4)

(57) [Claims] 1. Two glass substrates, at least one of which is transparent, are arranged to face each other with a predetermined gap, and a plurality of common scanning electrodes and a plurality of common electrodes parallel to each other are paired with the scanning electrodes. Electrodes and a plurality of data electrodes are formed on the other substrate so as to be orthogonal to the scanning electrodes, a discharge gas is enclosed in the gap, and a scanning pulse is applied to the scanning electrodes in a time-division manner. A driving method of a plasma display panel, wherein a display pixel is selected by selectively applying a data pulse to the data electrode in synchronization and a sustain discharge is performed only in the display pixel after the selection of the display pixel. In, the sub-scanning pulse having the opposite polarity to the scanning pulse is applied to the common electrode, and the potential difference between the scanning electrode and the data electrode is changed by selectively applying the data pulse. Driving a plasma display panel, characterized in that display pixels are selected by selectively changing the voltage within a range not exceeding an electric starting voltage and selectively generating a surface discharge between the scanning electrode and the common electrode. Method. 2. The method of driving a plasma display panel according to claim 1, wherein the scan pulse has a negative polarity and the sub-scan pulse has a positive polarity. 3. The method for driving a plasma display panel according to claim 1, wherein the sub-scanning pulse is constantly applied over substantially the entire period for selecting the display pixel. 4. The peak value of the sub-scanning pulse is larger than the peak value of the scanning pulse.
~ A method of driving a plasma display panel according to claim 3.