JP2002351391A - Plasma display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that write characteristics of a plasma display of constitution of a single-scan system, etc., wherein the length of a data electrode is long become worse owing to the voltage drop of a data pulse. SOLUTION: In a write period, the voltage of a maintaining electrode in a display line where the write characteristics become worse is varied reversely to the polarity of scanning pulses.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving apparatus for an AC plasma display panel (hereinafter referred to as an AC-PDP), and more particularly to a method for driving a surface discharge AC-PDP.

[0002]

2. Description of the Related Art The configuration of a general AC-PDP is disclosed, for example, in Japanese Patent Application Laid-Open No. Hei 8-212930. This is a first conventional example. The row electrode pairs are composed of scan electrodes and sustain electrodes, and the column electrodes are data electrodes. As shown in FIG. 1 of the above publication, a conventional drive voltage waveform has an initialization period,
It is divided into a writing period, a sustaining period, and an erasing period. In the writing period, data is written to each discharge cell in accordance with the display data, and only the written discharge cell emits display light in the sustain period.

In a writing period, a scanning pulse is applied to a scanning electrode, and a writing pulse having a polarity opposite to that of the scanning pulse is applied to a data electrode in accordance with display data.
Discharge is generated between both electrodes. Then, the discharge is used as a trigger to generate a discharge between the scan electrode and the sustain electrode, thereby writing data. A series of these discharges is called a write discharge.

As a writing method, there are a single scan method using one data electrode from the top to the bottom of the panel, and a double scan method in which the data electrode is divided into upper and lower parts and writing is performed simultaneously on the upper and lower parts. The double scan method can halve the time required for writing, thereby improving the image quality. However, compared to the single scan method, the data pulse generation circuit (data driver) needs to be connected up and down. The cost of the circuit increases.

[0005] Japanese Patent Application Laid-Open No.
1-65516. This is a second conventional example. In the above publication, a potential difference between a data electrode (an address electrode in the publication) and a scan electrode (a Y electrode in the publication) is changed in a writing period (an address period in the publication), so that a write discharge (an address discharge in the publication) is performed later. It is described that the writing discharge is reliably performed even in the cell where the writing is performed.

[0006]

The electrode width of the data electrode must be smaller than that of the scan electrode or the sustain electrode. For this reason, in the driving method as shown in the first conventional example, the voltage applied to the discharge cell decreases as the distance from the connection portion of the data driver decreases due to a voltage drop. This is remarkable when a high-definition plasma display in which the data electrode width must be narrowed or a single scan method in which the data electrode length is long is used.

Further, when trying to compensate for this voltage drop by the driving method shown in the second conventional example, the width of the changed voltage is limited by the performance of the scan pulse generation circuit (scan driver) or data driver. Therefore, when a change in voltage is increased, an expensive driver circuit with a high withstand voltage is required.

It is an object of the present invention to provide a plasma display capable of compensating for a writing discharge weakened by the voltage drop and stably writing without requiring a high-performance driver circuit.

[0009]

SUMMARY OF THE INVENTION In order to solve this problem, according to the present invention, by changing the potential of a sustain electrode during a writing period, writing can be stably performed even on a display row where writing is difficult. It is.

[0010] In the present invention, the writing period includes:
When writing to a display row far from the circuit that generates the write pulse, the potential of the sustain electrode is changed in the direction opposite to the polarity of the scan pulse to ensure reliable writing even if there is a voltage drop on the data electrode. Can be performed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has a plurality of pairs of row electrodes arranged on a substrate in parallel with each other, and a plurality of column electrodes arranged on an opposing substrate perpendicular to the row electrodes. A scan pulse is applied to one of the row electrode pairs (hereinafter, the electrode to which the scan pulse is applied is referred to as a scan electrode, and the other electrode is referred to as a sustain electrode). When the scan pulse is applied, a write pulse having a polarity opposite to that of the scan pulse is applied. A plasma display having a writing period in which display data is written by applying the voltage and a sustaining period in which a sustaining pulse is alternately applied to a row electrode pair, wherein the potential of the sustaining electrode is changed in the writing period. By changing the potential of the sustain electrode in the direction opposite to the scanning pulse in a display row where the writing discharge is weakened, stable writing can be performed even in a display row where writing is difficult. The perform.

Further, according to the present invention, in a writing period,
A plasma display characterized by continuously changing the voltage when the potential of the sustain electrode is changed in the direction opposite to the scanning pulse in a display row in which the writing discharge is weakened. Reliable writing can be realized while simplifying.

An embodiment of the present invention will be described below with reference to the drawings. The panel structure is the same as that shown in the first conventional example.

(Embodiment 1) FIG. 1 shows an example of a drive voltage waveform during a writing period according to Embodiment 1 of the present invention. In the writing period, scan electrodes SC1 to SCn
Is applied with a scan pulse, and a write pulse Pa is applied to the data electrodes D1 to Dm according to the display data at the same time as the application of the scan pulse, thereby performing data writing. At this time, at the time of scanning the first row (time a in the figure), the voltage Vp is applied to the sustain electrodes SU1 to SUn. The voltage decreases by a constant voltage Vq, and the voltage of the sustain electrode becomes 0 V during the last scanning of the n-th row (time b in the figure).

FIG. 2 shows an example of the configuration of the driving device of the present embodiment. Scan electrode SC1 drawn from panel
To SCn are scan electrode driving circuits, and sustain electrodes SU1 to S
A sustain electrode drive circuit is connected to Un. The scanning direction is from top to bottom. From the lower side of the panel, a data driver is connected to the data electrodes D1 to Dm and applies a write pulse according to the display data. The writing method is a single scan method.

The operation during the writing period will be described below. First, while a negative scan pulse is applied to the display row, a positive write pulse is applied to the data electrode to which data is to be written. A potential difference occurs between the data electrode and the scanning electrode, and a discharge occurs between the two electrodes. At the same time, this discharge triggers a discharge between the scan electrode and the sustain electrode, completing the data writing.

When a single scan type panel as shown in FIG. 2 is used, it is necessary to double the data electrode length as compared with the double scan type. Therefore, a voltage drop occurs as the distance from the data driver connection portion in FIG. 2 increases. Causes a reduction in the voltage of the data electrode. For this reason, in the driving method as shown in the first conventional example, the voltage of the write pulse applied to the discharge cell when writing the display row in the region (upper panel) remote from the data driver connection portion is performed. And the discharge between the data electrode and the scan electrode is weakened, resulting in unstable writing. Here, the unstable writing refers to a state in which writing discharge occurs or does not occur even if writing is attempted.

In this configuration, when writing a display row at the top of the panel where writing discharge is weak, a voltage is applied so as to increase the voltage of the sustain electrode. The potential difference of the sustain electrode increases. For this reason, of the writing discharge, the discharge between the scan electrode and the sustain electrode becomes strong, and the discharge between the data electrode and the scan electrode weakened by the voltage drop of the data electrode can be compensated for, whereby the data writing can be performed more reliably. Done.

(Embodiment 2) FIG. 3 shows an example of a drive voltage waveform during a writing period according to Embodiment 2 of the present invention. In the writing period, the scan pulse Pscn is applied to the scan electrodes SC1 to SCn, and the write pulse Pa is applied to the data electrodes D1 to Dm simultaneously with the application of the scan pulse in accordance with the display data, thereby performing data writing. At this time, no voltage is applied to the sustain electrodes of the display row to be scanned first, and thereafter, the voltage of the sustain electrodes increases by a constant voltage Vq as the scanning progresses to the second and third rows, At the time of the last scan of the n-th row (time b in the figure), the voltage of the sustain electrode becomes Vp. Other configurations are the same as those of the first embodiment.

In a display row whose writing order is slow, negative wall charges are formed on the data electrodes near the previously written display row. This means that in the discharge between the data electrode and the scan electrode in the write discharge, the data electrode becomes the anode,
This is because negatively charged particles generated by ionization after the discharge are accumulated on the data electrode. For this reason,
The actual voltage applied to the discharge cells is lower than the voltage applied from the outside. Depending on the conditions such as the electrode width and the material of the data electrode, the voltage drop due to the wall charge may be larger than the electrode voltage drop depending on the electrode length or the electrode width. In such a case, writing becomes unstable toward the bottom of the panel.

As in the present configuration, by increasing the voltage of the sustain electrode in the display row whose writing order is slow, that is, by increasing the sustain voltage as the lower part of the panel is written, the effect of the voltage drop due to the wall charge is increased. Can be alleviated, and writing can be reliably performed.

In the first and second embodiments, the voltage of the sustain electrode during the writing period is changed stepwise for each display row. However, when the deterioration of the writing state is relatively small, the row electrode is changed. Similar effects can be obtained by dividing into a plurality of row electrode groups (for example, dividing into three blocks of upper, middle, and lower) and changing the voltage for each row electrode group.

(Embodiment 3) FIG. 4 is an example of a drive voltage waveform according to Embodiment 3 of the present invention. In the writing period, a voltage Vp is first applied to the sustain electrode,
Thereafter, the voltage changes in a ramp shape from the start of the application of the scan pulse on the first row and decreases, and becomes 0 V at the start of the application of the scan pulse on the final n-th row. Other configurations are the same as in the first embodiment.

An advantage of this configuration is that the configuration of a drive circuit for generating an applied voltage is simplified by changing the waveform in a ramp shape. This is because, when the voltage is changed stepwise, as the number of steps increases, it is necessary to increase the number of control signals in the sustain electrode drive circuit or to devise a circuit configuration. That is, although the circuit configuration can be simplified by using this configuration, the same effect as that of the first embodiment can be obtained.

In the present configuration, the change in the voltage applied to the sustain electrode is changed in a ramp shape. Of course, even if the shape of this change is exponential, the circuit configuration is simplified and the same effect is obtained. Is obtained.

As described in each of the above embodiments, when the writing state does not change continuously but the range where the writing discharge is weakened is narrow, or when the range is irregular or partially present. Alternatively, the above voltage change may be partially applied only to the display row or the display row group in which the writing discharge is weakened. Needless to say, the effects described above do not depend on the difference in writing method such as single scan or double scan.

[0027]

As described above, according to the present invention, during the writing period, the potential of the sustain electrode is changed, and the potential of the sustain electrode is changed in the direction in which the polarity of the sustain pulse is opposite to that of the scanning pulse in a display row where the writing discharge is weakened. By making it change, writing can be stably performed even on a display row where writing is difficult.

Further, according to the present invention, when the potential of the sustain electrode is changed in the direction opposite to the scanning pulse in a display row in which the writing discharge is weakened, the voltage is continuously changed, whereby the driving circuit is changed. Can be surely written while simplifying the configuration of.

[Brief description of the drawings]

FIG. 1 is a driving voltage application timing chart of a plasma display according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a driving device for a plasma display of the present invention.

FIG. 3 is a drive voltage application timing chart of a plasma display according to a second embodiment of the present invention.

FIG. 4 is a driving voltage application timing chart of a plasma display according to a third embodiment of the present invention.

[Explanation of symbols]

 a, b, A, B Time D1 to Dm Data electrode Pa Write pulse Vp Maximum voltage applied to sustain electrode during write period Vq Voltage to be changed in one step Vscn Scan base voltage SC1 to SCn Scan electrode SU1 to SUn Sustain electrode

Claims (9)

[Claims] 1. A scanning pulse is applied to one of a row electrode pair,
A write period in which display data is written by applying a write pulse having a polarity opposite to that of the scan pulse when the scan pulse is applied to the column electrode, and in the write period,
A plasma display including a portion in which the other potential of the row electrode pair is temporally changed. 2. A scanning pulse is applied to one of the row electrode pairs,
A write period in which display data is written by applying a write pulse having a polarity opposite to that of the scan pulse when the scan pulse is applied to the column electrode, and in the write period,
When writing a display line where writing is unstable,
A plasma display comprising a portion where the other potential of the row electrode pair is temporally changed in a direction opposite to the polarity of the scan pulse. 3. A scanning pulse is applied to one of the row electrode pairs,
A write period in which display data is written by applying a write pulse having a polarity opposite to that of the scan pulse when the scan pulse is applied to the column electrode, and in the write period,
A plasma display, wherein the more the writing is performed on a display row far from the circuit for generating the writing pulse, the more the other potential of the row electrode pair is changed in a direction opposite to the polarity of the scanning pulse. 4. A scanning pulse is applied to one of the row electrode pairs,
A write period in which display data is written by applying a write pulse having a polarity opposite to that of the scan pulse to the column electrode when the scan pulse is applied, wherein the scan pulse has a negative polarity; A plasma display, wherein the potential of the other row electrode pair is increased as writing is performed on a display row farther from a circuit for generating a pulse. 5. A scanning pulse is applied to one of the row electrode pairs,
A write period in which display data is written by applying a write pulse having a polarity opposite to that of the scan pulse when the scan pulse is applied to the column electrode, and in the write period,
When writing to a display row that is slow to scan,
A plasma display, wherein the other potential of the row electrode pair is changed in a direction opposite to a polarity of the scan pulse. 6. A scanning pulse is applied to one of the row electrode pairs,
A write period in which a display pulse is written by applying a write pulse having a polarity opposite to that of the scan pulse to the column electrode when the scan pulse is applied, wherein the scan pulse has a negative polarity; A plasma display wherein the potential of the other of the row electrode pair is increased as writing is performed on a display row which is slower to perform. 7. The plasma display according to claim 1, wherein the writing period includes a portion where the other potential of the row electrode pair is continuously changed. 8. The plasma display according to claim 1, wherein during the writing period, a change in the other potential of the row electrode pair has a ramp shape. 9. The plasma display according to claim 1, wherein a change in the other potential of the pair of row electrodes is exponential during the writing period.