JPS6156518B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new driving method that prevents erroneous discharge in a self-shifting gas discharge panel.

A self-shifting gas discharge panel is a panel that can sequentially shift discharge spots generated according to written information from one end toward the other end, and display the written content statically when the writing operation is completed. Various types have been proposed. Figure 1 shows this type of panel with a 2x2 phase meander electrode structure already proposed in Japanese Patent Application Laid-Open No. 53-8053, which is arranged alternately in the horizontal direction on one substrate. 2 groups of shift electrodes
yij and y ₂ j (j is a positive integer), and two groups of shift electrodes x ₁ j and x ₂ j arranged alternately on the other substrate in the same horizontal direction. have. These 2×2 groups of electrodes on both sides are covered with dielectric layers on their respective substrates, and are arranged facing each other with a gas space for discharge in between, as is already well known. Thus four electrode groups
In the opposing gaps between y ₁ , y ₂ and x ₁ , x ₂ , four-phase discharge cells aj, bj, cj, and dj are arranged according to the arrangement order of these electrodes.
are arranged in a regular periodic manner, and a plurality (for example, two) of lateral shift channels SC ₁ to SC ₂ are formed along the arrangement line of each electrode as shown in the figure. At one end of each shift channel SC ₁ to _{SC 2} , write electrodes w ₁ , w ₂ are provided opposite to the first y ₁₁ electrode, and the four shift electrodes ₁ j, y ₂ j and
In this display line, x ₁ j and x ₂ j are led out to terminals Y1, Y2, X1, and X2 by bus connections as shown.

Figure 2 shows an example of the drive voltage waveform, VY1,
Voltage waveforms in which VX1, VY2 and VX2 are applied to the four shift electrode groups through each bus conductor;
VA, VB, VC, and VD are voltage waveforms applied to the four-phase discharge cells A to D as a composite voltage of the electrode voltage waveforms, respectively. Also, VWi (i is a positive integer)
is the write voltage waveform applied to the write electrode group, and VWc is the combined voltage waveform applied to the write discharge cell W.

As is clear from this Figure 2, the unit period t ₀ ~
At _t3 , basic pulse trains indicated by ~ are distributed to each phase so as to rotate sequentially. For example, referring to the unit period _t0 , when a write pulse Pw is applied to the write electrode _w1 and a write voltage waveform as shown in _VW1 is applied to the write discharge cell w, the first discharge occurs in the discharge cell. Spots occur. At this time, since a shift pulse Ps such as VA is applied to the group aj to which the first discharge cell of the shift channel SC ₁ belongs, the pilot effect of the write discharge spot causes the first discharge adjacent to the write discharge cell to A discharge spot is simultaneously generated in cell _a1 . As the application of the basic pulse train is switched in the next unit period _{t 1 ,} t _{2 .} . . , the discharge spot generated in the discharge cell a 1 is divided into two adjacent discharge cells a ₁・b ₁ , b ₁・c ₁ . . . are sequentially shifted toward the other end along the shift channel SC ₁ in a shared manner. During this time, an erasing pulse Pe is effectively applied to the discharge cell group whose discharge spot has been shifted based on the phase difference between the pulses applied between the opposing electrodes, and the erasing operation of the discharge spot is performed. .

As described above, this type of self-shifting panel performs writing and shifting operations of discharge spots corresponding to input information.However, as the shifting operation is repeated in such panels, desired discharge cells are However, there is an undesirable problem in that accidental erroneous discharge occurs in discharge cells located at unrelated positions. This accidental discharge phenomenon is not observed at all in the well-known matrix type panel, but is unique to self-shift type panels, and disrupts information within the panel and obstructs display operations.

As a result of various studies on the problems peculiar to this self-shifting panel, the present inventors have determined that the cause of accidental discharge is the non-uniform distribution of space charge within the discharge space after the discharge spot shifts and the surface of the protective layer. We have determined that this is due to abnormal wall charge accumulation (hereinafter these abnormal charges will be referred to as charge distortion). However, when this charge and distortion increase due to repeated shift operations, the abnormal electric field based on this charge works together with the shift voltage to induce an avalanche phenomenon in the vicinity, causing the accidental error mentioned above. This causes a discharge.

From the above-mentioned viewpoint, the present invention aims to effectively prevent erroneous discharge in a self-shifting gas discharge panel.
Based on the experimental results that the writing sequence changes significantly over time, a new driving method is provided in which the writing sequence is improved to improve the panel quality.

Briefly stated, the present invention involves, in a self-shifting gas discharge panel, an operation of generating discharge spots in all discharge cells of a shift channel prior to an operation of generating discharge spots corresponding to input information, and a method of generating discharge spots. This feature is characterized by an operation to reduce the amount of discharge, thereby eliminating the accidental erroneous discharge that has been a problem in the past.

Note that the operation of generating discharge spots in all discharge cells of the shift channel is inserted when new input information is written to a display row in a non-display state.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the drawings.

First, before explaining the driving method according to the present invention, the characteristics of the probability of occurrence of accidental false discharge and the amount of charge distortion changing depending on the fixed state of the discharge spot will be explained with reference to FIGS. 3 and 4. explain. In other words, Figure 3 shows the IF of alumina (Al ₂ O ₃ ).
In a test panel on which a protective layer of magnesium oxide (Mgo) was formed, the amount of charge distortion was accumulated to a level just before an erroneous discharge occurred, and the fixation time of the discharge spot was plotted on the horizontal axis as a parameter. A characteristic diagram is shown in which the number of shift operations is plotted and the probability of occurrence of false discharge is plotted on the vertical axis. As is clear from this figure, the probability of occurrence of erroneous discharge changes significantly depending on the fixed time length of the discharge spot. In other words, if a discharge spot that occurs in a specific discharge cell is erased immediately, an erroneous discharge will occur from the first shift operation, but if it is fixed for 20 seconds, an erroneous discharge will not occur until the 5th or 6th shift operation. Since the probability is 1 or less, the incidence of erroneous discharge is significantly reduced.

Furthermore, FIG. 4 is a diagram schematically showing changes in the amount of charge distortion during shift operation and fixed display operation for a specific discharge cell.As shown by the solid line, the amount of charge distortion increases as the shift operation is repeated. If it is clear that the amount decreases during the fixed display operation and does not change during the erasing operation, and the amount exceeds the predetermined level SL during the repeated shift operation, then P
A false discharge occurs as shown in .

Thus, it is clear that the charge distortion is significantly reduced by fixing the discharge spot for a predetermined period of time, and the reason for this reduction can be considered as follows. That is, as shown by the shaded area in the diagram of the main part of the electrode in FIG. 5, charge distortion is concentrated in areas other than the normal discharge position, and this is neutralized and stabilized by fixing the discharge spot. This is for the purpose of

The present invention utilizes the fixed operation of the discharge spot as described above, and when rewriting information, prior to writing the discharge spot, all discharge cells of the shift channel are discharged, and then this discharge is extinguished. As a result, the charge distortion on the discharge surface is significantly reduced.

FIG. 6 is a drive voltage waveform diagram for achieving such discharge spot generation operation, and shows the case where discharge cell groups dj and aj of the shift channel are lit first. For example, in the period t ₁₁ - t ₁₂ , in order to light up all the discharge cells of the shift channel before rewriting the information, the X side bus terminal
1 and X2, a negative lighting pulse P _R as shown in the figure is applied to the bus terminal Y1 on the Y side.
Suppose that we apply Then, for the D-phase and A-phase discharge cell groups dj and aj defined between the electrode Y ₁ j belonging to this terminal and the electrodes x ₁ j and x ₂ j opposite to this electrode, A voltage waveform as shown at VD is applied, which causes the first discharge spot to occur simultaneously in these cells.

In the next period _t12 - _t13 , shift pulses are applied to the cell groups of each phase, so the discharge cell groups of the D phase and A phase maintain their discharge spots and are adjacent to these cell groups. Phase B and C
Cell groups bj and cj of the phase will produce a discharge spot due to the pilot effect. As a result, all cells of the shift channel will be lit. Then, in the next period t ₁₃ - _{t 14} , when a shift pulse is applied with a phase difference between the X side bus line and the Y side bus line, the erase pulse Pe (D phase and A
(only the phase shown) is added, thereby erasing all the discharge spots in the cell group.

After removing most of the charge distortion on the discharge surface of the panel by such a write operation, the period
From _t14 to _t16 , the write operation and shift operation of the discharge spot corresponding to the same input information as described in FIG. 2 are performed. According to the above write sequence, there will be no accidental erroneous discharge. That is, to describe this effect with reference to FIGS. 3 and 4 again, first of all, even in the panel shown in FIG. 3 in which erroneous discharge is extremely likely to occur, it is not observed at all until the fourth shift operation. First, the probability of occurrence is 1 at the ninth shift operation. Next, as shown by the dotted line in FIG. 4, charge distortion is significantly reduced by fixing all cells for a predetermined period of time. It can be seen that this is a significant improvement.

By the way, the time width τfw for all cells to light up is 1 sec>
Although it is possible to freely select between τfw > 1 msec, according to the experimental results of the present inventors, it was confirmed that τfw = 10 msec is sufficiently effective. FIG. 7 is a characteristic diagram obtained by measuring how the probability of false discharge occurrence changes with this τfw using the voltage (wave height) value of the shift pulse as a parameter. The test panel was the same as that shown in Figure 3. As can be seen from this figure, the ignition voltage near the minimum shift voltage value, which is higher than the ignition voltage of the adjacent discharge point, is reduced by the pilot effect.
Even when Vsh=76 (V), the probability of occurrence can be reduced to 0 with τfw=10 msec or so.

FIG. 8 shows an example of a drive circuit and drive control pulses for generating the lighting pulse _PR for the Y-side bus terminal Y1. In the same figure a, Q ₁ and Q ₂ are transistors that control the generation of shift voltage Vsh.
Q ₃ and Q ₄ are transistors that control the generation of lighting voltage V _R , I ₁ and I ₂ are inverters, C ₁ to C ₄ are capacitors, R ₁ to _{R 8} are resistors, B is a buffer circuit, and Vcc is the operating voltage. -V _R is the lighting voltage source, and Vsh is the shift voltage source. For example, for example, a shift timing pulse is applied to the first input terminal in ₁ at time t ₁ for b of the same figure.
When Ts is applied, the transistor Q ₁ is turned on and Q ₂ is turned off, so that the shift voltage Vsh is applied to the output terminal out connected to the bus line Y1, that is, the shift pulse Ps rises.

At the next time _t2 , when the timing pulse is stopped generating, transistor _Q1 is turned off and _Q2
is turned on, thereby grounding the output terminal out, that is, the falling edge of the shift pulse. Then, at the next time _t3 , when the up command pulse Pu is applied to the input terminal _in2 , the transistor _Q4 is turned on and the lighting voltage -V _R is applied to the output terminal out, that is, at the rising edge of the lighting pulse _PR . becomes. Then, at time _t4 when the up command pulse falls, when the down command pulse Pd is input to the input terminal _in3 , the transistor _Q3 is turned on, so the output terminal out is grounded, that is, the lighting pulse falls. . Thus, a voltage waveform as shown at VY ₁ in FIG. 8b is supplied to the Y example bus terminal Y1.

Although one preferred embodiment of the present invention has been described above, the essence of the present invention is not limited to this embodiment, and various modifications are possible, and the modified examples are listed as follows.

1. As a method for lighting up all discharge cells in a shift channel, a shift pulse is applied to all the cells in advance, and a discharge spot is generated in the write discharge cell, and this discharge spot is used as a pilot flame to light up all the cells. Good too. It is also possible to light up all the cells by applying a shift pulse to all the cells using the previously written discharge spot as a pilot flame.
Furthermore, it is of course possible to apply a lighting pulse in common to the two bus bars on the Y side to light all the discharge cells at the same time.

2. The method of extinguishing the discharge spots after all cells are lit is not limited to applying an erase pulse to all cells, but also by sequentially shifting the discharge spots corresponding to new input information onto the shift channel.
The discharge spot may be extinguished by sending it to the other end of the panel.

3. In addition to the meandering electrode structure, the applicable panel may also be a panel having a crossed electrode structure as shown in Japanese Patent Publication No. 51-25296.

In relation to items 1 and 3 of the above modification, Fig. 9 shows that when a shift pulse is applied to all discharge cells of a crossed electrode type panel, erroneous discharge can be caused by changing the application time width τfw and its peak value Vsh. A characteristic diagram shows how the probability of occurrence changes. As is clear from this figure, in such a panel, by lighting all the cells for a short time, the probability of erroneous discharge occurrence can be significantly reduced, and accidental erroneous discharges almost never occur.

Now, as is clear from the above explanation, the writing (driving) method of the present invention has the great feature of being able to significantly improve panel quality by eliminating the accidental erroneous discharge that is characteristic of self-shifting panels. A slight effect can be obtained. Therefore, it is extremely advantageous to apply this invention to a self-shifting gas discharge panel.

[Brief explanation of the drawing]

Figures 1 and 2 are electrode arrangement diagrams and drive voltage waveform diagrams showing one example of a self-lift type gas discharge panel to which the present invention is applied, and Figures 3 to 5 show accidental erroneous discharge in this panel. FIG. 6 is a diagram showing an example of the drive voltage waveform according to the present invention, FIG. 7 is an explanatory diagram of the effect of the drive voltage pulse of FIG. 6, and FIG. 8 is a diagram showing the driving voltage waveform of FIG. 1 of the drive circuit for generating voltage waveform VY ₁
An example configuration diagram, FIG. 9, is an explanatory diagram of the effect of the present invention using a self-shifting panel different from that in FIG. 1. X1, Y1, X2 and Y2: bus terminal, xij
and yij: electrode, aj to dj: discharge cell group, w: write discharge cell, Pw: write pulse, Ps: shift pulse, Vsh: shift voltage, P _R : lighting pulse, -
V _R : lighting voltage, Pe: erasing pulse.

Claims (1)

[Scope of Claims] 1. A shift channel consisting of a periodic arrangement of a plurality of groups of discharge cells defined by an electrode arrangement regularly connected to a plurality of bus bars, and a write discharge at one end of the shift channel. In a self-shifting gas discharge panel configured to include write electrodes that define cells, an operation of generating discharge spots in all discharge cells of the shift channel prior to an operation of generating discharge spots corresponding to input information;
A method for driving a self-shifting gas discharge panel, characterized in that the discharge spot is eliminated. 2. The operation of generating discharge spots in all the discharge cells of the shift channel is carried out by the electrodes (y ₁ j−x ₁ j, y ₁ j) defining at least one group of discharge cells (aj, dj).
−x ₂ j) to generate a discharge spot in the cell group (aj, dj) by applying an ignition voltage (P _S +P _R ) sufficient to discharge the cell group (aj, dj);
All discharge cell groups (aj,
bj, cj, dj) defining the electrodes (y ₁ j−x ₁ j, y ₂ j−
x ₂ j, y ₂ j−x ₂ j, y ₁ j−x ₂ j)
_S ) is applied to all discharge cell groups (aj, bj, cj,
2. The method of driving a self-shifting gas discharge panel according to claim 1, further comprising the step of generating a discharge spot on a dj).