JPS5813917B2 - Driving method of plasma display panel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a driving method for ensuring reliable operation of a plasma display panel.

Generally, in order to drive a plasma display panel, a discharge maintenance voltage, that is, a sustain voltage, is applied to each cell of the panel, a write voltage is applied to the required cells to cause the cells to discharge and emit light, and then In this case, discharge light emission is continued using only a sustain voltage, or an erase voltage is applied to a required cell to stop discharge light emission from that cell.

As mentioned above, the method of determining each voltage to be applied to a cell is well known, and a standard case will be explained with reference to FIG.

In FIG. 1, each line represents a voltage level, and the symbol Vf1 indicates that a sustain voltage is applied to the plasma display panel, and the sustain voltage is gradually increased to select one of the cells among all the cells. However, the symbol ■fn represents the voltage when all the cells discharge and emit light, and the symbol vs1 represents the voltage when the sustain voltage is gradually lowered to It represents the voltage when even one cell stops emitting discharge, and the symbol Vsn represents the voltage when all cells stop emitting discharge.

Now, usually write selected by random address,
When selectively erasing, the write voltage is set to a voltage slightly higher than the voltage ■fn, the erase voltage is set to a voltage slightly lower than the voltage ■sn, and the sustain voltage is set to a voltage as shown by the symbol Vs. (2) The voltage is set between 81 and the voltage Vf1.

Each voltage is then applied to the panel in the relationship shown in FIG.

In FIG. 2, 21 represents a sustain voltage waveform, 22 represents an erase voltage waveform, and 23 represents a write voltage waveform.

By the way, the sustain voltage 5 is determined as described above.
Although it is fixedly set at a level that can reliably maintain the discharge light emission of the panel, it does not mean that the panel will always operate stably.

In other words, when the voltage of the external power supply fluctuates, the sustain voltage naturally fluctuates, and for example, if the sustain voltage decreases, even if a write voltage is applied, the cell wall charge will be slow to reach a stable condition. , it becomes a so-called disappearing state.

Further, when the sustain voltage increases, even if an erase voltage is applied, discharge light emission cannot be stopped.

Furthermore, since each voltage mentioned above is set as if the panel were new, if the characteristics of the panel change over time,
Unable to perform the desired operation.

When driving a plasma display panel, the present invention provides the ability to operate a plasma display panel even when the sustain voltage fluctuates due to fluctuations in the external power supply or when the characteristics of the panel change over time.
During writing or erasing, the purpose of sustaining is to rapidly increase the wall charge and transition to a stable condition, or rapidly decrease the wall charge and transition to an unstable condition, thereby ensuring operation. In a plasma display panel that maintains discharge light emission by periodically applying a voltage (current), when writing the discharge light emission to a selected cell or erasing the discharge light emission in the selected cell, the access signal is used. Regarding the sustain voltage (current) for a predetermined number of cycles either before or after the application point, or both, in the case of writing, the sustain voltage (current) is at a level higher than the normal level, and in the case of erasing, the sustain voltage (current) is higher than the normal level. The present invention provides a plasma display panel driving method characterized by applying a small level sustain voltage (current), which will be described in detail below.

FIG. 3 shows an example of a voltage waveform when writing to a panel by implementing the present invention.

In FIG. 3, 32 represents a sustain voltage waveform, 31a represents a modulated sustain voltage waveform, and 32 represents a write voltage waveform.

That is, the sustain voltage ■s shown by the waveform 31 is initially applied to the panel, but after the write voltage Vf shown by the waveform 32 is applied, the modulated sustain voltage v8w shown by the waveform 31a is applied to the panel for several cycles. is applied.

As shown in FIG. 1, this modulated sustain voltage v8w has a higher voltage level than the normal sustain voltage v5.

Therefore, after the write voltage Vf is applied to the cell, the modulation sustain voltage V8w at a high voltage level as described above is continuously applied for several cycles, so that the wall charge in the cell rapidly rises and shifts to a stable condition. can do.

FIG. 4 shows an example of a voltage waveform when the present invention is implemented to erase the discharge light emission of the panel.

In the figure, 41 indicates a sustain voltage waveform, 41a indicates a modulated sustain voltage waveform, and 42 indicates an erase voltage waveform.

That is, the sustain voltage 8 shown by the waveform 41 is initially applied to the panel, but after the erase voltage 8 shown by the waveform 42 is applied, the modulated sustain voltage shown by the waveform 41a changes over several cycles. (2) This is to apply se.

As shown in FIG. 1, this modulated sustain voltage Vse is set at a lower voltage level than the normal sustain voltage V8.

Therefore, after the erase voltage Ve is applied to the cell, the modulation sustain voltage SE at a low voltage level as described above is continuously applied for several cycles, so that the wall charge in the cell rapidly falls, creating an unstable condition. In other words, the process moves to the erasing condition.

Alternatively, the modulation sustain voltage (se) may be applied for several cycles before the erase voltage Ve is applied.

As can be understood from the explanation regarding FIGS. 3 and 4, according to the present invention, by applying a modulated sustain voltage before and after applying a write voltage or an erase voltage,
The state of the cell is changed to ensure that writing or erasing is performed.

Further, in the illustrated example, a case has been described in which the amplitude of the sustain voltage is changed as the modulated sustain voltage, but the present invention is not limited to this, and the amplitude related to the sustain current may be changed. FIG. 5 shows an example of a circuit suitable for implementing the present invention. In the figure, Q1 to Q3 are transistors, D1 to D
3 is a diode, T1 to T3 are input terminals connected to the emitters of transistors Q1 to Q3, PW, Ps, P
Reference character e represents a control terminal connected to the bases of transistors Q1 to Q3, E represents a sustain power supply, CP represents a clock pulse input terminal, and OP represents an output terminal.

In this circuit, the control input terminals "w, Ps'Pe" are
TTL (Transistor-Transistor
Logic).

For example, if a pulse of t1p is input to the terminal PW, only the transistor Q1 is turned on if the input levels of the other terminals Ps and Peo are "0".

Then, if a voltage of ■8wl is applied to the sustain power supply E and a clock pulse is input to the terminal CP at that time, a pulse of the modulated sustain voltage v8w having a peak value equal to the peak value of the voltage vSw' is output from the terminal OP. and applied to the panel.

Similarly, the terminals P8 and Po are driven as appropriate, and the normal sustain voltage Vs or the modulated sustain voltage Vso used for erasing is output from the terminal OP and applied to the panel.

As can be seen from the above explanation, according to the present invention, plasma
The amplitude of the sustain voltage or current for a predetermined number of cycles is changed either before or after the point in time when a writing or erasing access signal is applied to the display panel, or both, to a large extent in the case of writing and a small amount in the case of erasing, and then, Access can be ensured by returning to the normal state again, and the effects of fluctuations in external power supply voltage, changes in panel characteristics, etc. can be completely eliminated.

[Brief explanation of drawings]

Figure 1 is a diagram explaining the level relationship of the voltages applied to the plasma display panel, Figure 2 is a voltage waveform diagram showing a conventional example of the voltage waveform applied to the panel, and Figures 3 and 4 are the diagrams used in this book. FIG. 5 is a voltage waveform diagram showing an example of a voltage waveform applied to a panel when carrying out the invention, and FIG. 5 is a circuit diagram showing an example of a circuit suitable for carrying out the invention. In the figure, {circle around (8)} represents a normal sustain voltage, vf represents a write voltage, ■o represents an erase voltage, VSW represents a modulated sustain voltage applied during writing, and VSe represents a modulated sustain voltage applied during erase, respectively.

Claims (1)

[Claims] 1. In a plasma display panel that maintains discharge light emission by periodically applying a saturation voltage (current), when writing the discharge light emission in a selected cell or erasing the discharge light emission in the selected cell, The sustain voltage (current) for a predetermined number of cycles either before or after the access signal is applied.
For writing, the sustain voltage (current) is higher than the normal level, and for erasing, the sustain voltage (current) is usually m
A plasma display panel driving method characterized by applying a sustain voltage (current) at a level smaller than the current level.