JPS629915B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new driving method that eliminates erroneous discharge without reducing the write operation margin in an AC discharge type self-shifting gas discharge panel.

As is already well known, in a self-shifting gas discharge panel, a shift channel consisting of a periodic arrangement of multiple groups of shifting discharge cells is defined by electrodes regularly connected to multiple bus bars, and one end of the shift channel is defined by a periodic arrangement of multiple groups of shifting discharge cells. A write electrode for defining a write discharge cell is provided at each of the electrodes. Then, when a write voltage is applied to the write electrode in accordance with the character information to be written, the first discharge spot is generated, and thereafter, by applying a shift voltage to the bus bar in a predetermined order, the first discharge spot is successively changed to the adjacent one. Driving is performed to shift the discharge cells.

Therefore, the information written in the form of discharge spots is
It is sent from the writing side end of the shift channel to the other end in such a manner that one pixel corresponds to one period of the shift discharge cell array, and if the shift operation is stopped on a specific discharge cell group during that period, a fixed display is given. It will be done.

By the way, when performing the above-mentioned shift operation, in the conventional self-shift panel, as the shift operation is repeated, the discharge surface at a position unrelated to the desired shift discharge cell (hereinafter abbreviated as discharge cell) There is the undesirable problem of accidental false discharges. This accidental erroneous discharge phenomenon is not observed at all in conventionally well-known matrix-type panels, but is unique to self-shifting panels, and disrupts information within the panel and obstructs display operations.

The present inventors believe that the cause of such accidental false discharge is
This is due to the accumulation of abnormal wall charges on the surface of the dielectric layer other than the normal discharge position, and the abnormal electric field based on this charge works together with the shift pulse (voltage) to induce an avalanche phenomenon in the vicinity. was investigated. It has also been experimentally determined that the abnormal wall charge can be neutralized by keeping the discharge spot stationary (fixed) for a predetermined period of time. Based on these experimental results, the present inventors previously proposed a new full write sequence that completely eliminates the accidental erroneous discharge. To put it simply, this complete write sequence involves adding all lighting operations to generate discharge spots in all discharge cells of the shift channel, prior to operations to generate discharge spots to be displayed in response to input information. After
An operation is added to eliminate this discharge spot, and as a result of these operations, the abnormal wall charge is neutralized before information is written, thereby preventing accidental erroneous discharge.

However, in such a full write sequence, as will be described later, unnecessary discharge is likely to occur in the picture element closest to the write discharge cell when writing the first information due to the erase pulse that extinguishes the discharge spots of all discharge cells. , this creates a new problem in that the upper limit of the write operation margin is severely limited.

Therefore, an object of the present invention is to provide a new write sequence that eliminates the above-mentioned unnecessary discharge, and thereby:
The purpose of this invention is to improve the display quality of the panel by improving the write operation margin and eliminating the accidental erroneous discharge that is characteristic of self-shifting panels.

Briefly stated, the present invention includes a shift channel consisting of a periodic arrangement of a plurality of groups of shifting discharge cells determined by an electrode arrangement regularly connected to a plurality of bus bars, and one period of the discharge cell arrangement. In a self-shifting gas discharge panel having a structure in which a write electrode is provided at one end of the shift channel to define a write discharge cell, a discharge spot to be displayed is generated in response to input information. Prior to the operation, an all-lighting operation is performed to generate discharge spots in all discharge cells of the shift channel, and some of the discharge cells in the discharge cell row of each cycle are exposed to the discharge spots generated by this all-lighting operation. After each discharge spot is erased, a shift operation is performed to commonly shift the remaining discharge spots to a position separated by at least one pixel, and a shift including the discharge cells in which the shifted remaining discharge spots exist. This method is characterized in that a full erasing operation is added to all discharge cells of the channel.
Note that the all-lighting operation to generate discharge spots in all discharge cells of the shift channel is performed before writing input information to be newly displayed on a display line in a non-display state when rewriting a display line, etc. It is inserted.

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

First, prior to explaining the driving method of the present invention, the structure and operation example of a self-shifting gas discharge panel to which the present invention is applied, and a conventional full write sequence that eliminates accidental erroneous discharge will be explained.
Figure 1 shows a self-shifting panel with a 2 x 2 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. Two groups of shifted electrodes
Two groups of shift electrodes y ₁ j and y ₂ j having a plurality of lines y ₁ j and y ₂ j (j is a positive integer) and also arranged alternately in the horizontal direction on the other substrate. It has a line of. 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 the four electrodes
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. Note that one picture element is composed of four discharge cells a, b, c, and d. Write electrodes w 1 , w ₂ are provided at one end of _each shift channel SC ₁ -SC ₂ facing the first y ₁₁ electrode, and the four shift electrodes y ₁ j, y ₂ j and x ₁ j, x ₂ j is connected to terminals Y1, Y2,
It is derived into X1 and X2.

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 composite voltages 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 t ₀ , when a write pulse P _W is applied to the write electrode w ₁ and a write voltage waveform as shown in VWi 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 P _S 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 cell adjacent to the write discharge cell to A discharge spot is simultaneously generated in the discharge cell _a1 . As the application of the basic pulse train is switched in the next unit period _{t 1 ,} t ₂ , etc., the discharge spot generated in the discharge cell a 1 is transferred to 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-shift type panel performs writing and shifting operations of discharge spots corresponding to input information. However, in such a panel, the electrode arrangement shown in FIG. As shown by the diagonal lines in the figure,
Abnormal wall charges are accumulated on the surface of the dielectric layer other than the normal discharge position. The amount of accumulated wall charge increases as the shift operation is repeated, and if it exceeds a predetermined amount, accidental erroneous discharge will be induced as described above.

This abnormal wall charge charges the discharge spot for a predetermined period of time.
For example, it is clear from the experimental results that it is significantly reduced by fixing it for 10 msec. However,
Based on this experimental result, prior to writing the discharge spot for rewriting information, all discharge cells of the shift channel are discharged, and then this discharge is extinguished, thereby significantly reducing the abnormal wall charge accumulation. We have proposed a writing method that allows

FIG. 3 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 Yij belonging to this terminal and the electrodes x ₁ j and x ₂ j opposite to this electrode, VA and VD in the same figure are A voltage waveform as shown is added,
This causes the first discharge spots to occur simultaneously in these cell groups.

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 most of the abnormal wall charges on the discharge surface of the panel are removed by such a write operation, during the period _t14 - _t16 , the write operation and shift of the discharge spot corresponding to the same input information as described in FIG. 2 are performed. perform an action. According to the entire write sequence described above, there will be no accidental erroneous discharge.

However, in such a full write sequence, as described above, due to the erase pulse for extinguishing the discharge spots of all discharge cells, unnecessary discharge occurs in the picture element closest to the write discharge cell when writing the first information. This creates a new problem in that the upper limit of the write operation margin is severely limited. That is, the erase pulse applied after the entire write sequence is the same as the erase pulse for the erase operation accompanying the shift operation of the discharge spot, but according to this erase pulse, the dielectric material is damaged due to the following reason. There is a phenomenon in which wall charges accumulated on the layer surface are not completely and uniformly erased over the entire panel. That is,
The erasing operation that accompanies the shift operation is mainly caused by the neutralization of wall charges caused by the discharge of adjacent discharge cells.
Due to this neutralization phenomenon, the wall charge on the surface of the dielectric layer has been significantly reduced, so the erase pulse applied at this time is sufficient to erase the wall charge remaining after the neutralization phenomenon. Ta. To describe it in more detail with reference to the drive waveforms in FIG. 2, for example, an A-phase shift discharge cell aj that enters an erase operation after passing a discharge spot is applied with an erase pulse train in the corresponding unit period _t2 . By doing so, the wall charge on the surface of the corresponding dielectric layer is eliminated.
A discharge due to the shift pulse P _S is generated in the adjacent B-phase shift discharge cell bj at a timing immediately before the application of the erase pulse Pe, and the shift discharge cell is The wall charges corresponding to aj are partially neutralized and significantly reduced, and the remaining wall charges that have been reduced are eliminated by the erase pulse Pe. Note that the erase pulse Pe has a wider width than the erase pulse (pulse width of 1 μsec or less) in a well-known matrix type gas discharge panel because it uses the residual wall charge with a small potential level to generate an erase discharge. Pulses are required, and pulses with a pulse width of 1.5 to 2 μsec are usually used.

However, the operation of erasing the discharge spots of all the discharge cells does not involve a shift operation, and because the conditions are different from those of the erasing operation that accompanies the shift operation, the wall charges accumulated on the surface of the dielectric layer are transferred to the entire panel. Therefore, it is not possible to completely and uniformly erase the data over the entire period. This residual wall charge causes the ignition voltage of the corresponding discharge cell to be lower than normal, making it easier to discharge the discharge cell. Therefore, if a residual wall charge remains in a shift discharge cell adjacent to a write discharge cell, when a write voltage is applied to the write discharge cell (w in FIG. 1) to write the first information, the residual wall charge Shift discharge cells to which shift voltages are applied at the same timing as the write discharge cells due to charge (d1 in Figure 1)
Also, in the shift discharge cell (a2 in FIG. 1) that is closest to the shift discharge cell adjacent to the write discharge cell (a1 in FIG. 1), a shift discharge cell (a2 in FIG. 1) occurs as the intensity of the write discharge cell discharges. Due to the pilot effect of a large amount of electrons, ions, etc. and the residual wall charge, unnecessary discharge (hereinafter referred to as "unnecessary discharge") is simultaneously generated by mistake. Note that this unnecessary discharge does not occur when a discharge spot corresponding to information subsequent to the first information is generated or when a shift discharge whose discharge intensity is not very large is generated.

Figure 4 is a diagram schematically showing the display mode when an unnecessary discharge occurs in a display line in which seven shift channels are arranged vertically in parallel and can display characters of 5 x 7 dots, and the black circle point P is an unnecessary discharge point.

In order to prevent the above-mentioned unnecessary discharge, the upper limit of the allowable range of the peak value of the write voltage waveform applied to the write discharge cell must be lowered to reduce the intensity of discharge, and therefore the allowable range becomes narrower. The write operation margin corresponding to the difference between the upper and lower limits of the allowable range will decrease. If the write margin decreases, stable and reliable write operations cannot be obtained in practical use.

An object of the present invention is to improve the write operation margin by eliminating unnecessary discharge during subsequent information writing when the full write sequence is employed in a self-shift type gas discharge panel. In short, the present invention provides a method for discharging some discharge cells of a discharge cell row in each period among the discharge spots generated by the all-cell lighting operation between the all-discharge cell lighting operation and the all-discharge cell erasing operation in the all-write sequence. After each discharge spot is erased, the remaining discharge spots are erased by at least one discharge spot.
This method is characterized by inserting an operation for shifting to a position separated by a picture element, thereby completely erasing the wall charges on the dielectric layer corresponding to the picture element.

Fig. 5 is a drive voltage waveform diagram for achieving such a discharge spot generation operation, and the major difference between this diagram and Fig. 3 is that there is one picture between the all-cell lighting state and the all-cell erasing state. The elemental shift operation is inserted, and the B-phase and C-phase discharge cell groups
The difference is that composite voltage waveforms VB and VC that are not added to bj and cj are added. Therefore, to describe this difference in detail, in a state in which all discharge cells are lit (period t ₂₂ - t ₂₃ ), during period t ₂₃ - t ₂₄ , the illustrated values for bus lines Y1, X1, Y2 and X2 are When such voltages VY1, VX1, VY2, and VX2 are applied, the following operation is performed. i.e. period
B-phase and C-phase discharge cell groups also at t ₂₃ - _{t 25}
An erase pulse Pe is added to bj and cj, thereby erasing the discharge spot in the cell group. Then, during the period _{t24 - t28} , two _adjacent discharge cell groups aj, bj, bj,
A shift pulse P _S is applied to cj, cj・dj, and dj・aj in order, and as a result, the discharge spots that have been generated in the two discharge cell groups dj and aj are changed in such a manner that the two discharge cell groups are shared by aj・bj → One picture element is shifted along the shift channel in the order of bj/cj→cj/dj→dj/aj. During this period, an erase pulse Pe is applied to the discharge cell group that has been shifted, thereby performing an erase operation.

Such a shift operation neutralizes the wall charges on the surface of the dielectric layer of the panel, especially the wall charges of the four discharge cells a1, b1, c1, and d1 belonging to the first picture element adjacent to the write discharge cell. is eliminated by this neutralization. Thereafter, in the period t ₂₈ - t ₂₉ , the erase pulse Pe is applied to all the discharge cell groups in the same manner as shown in the period t ₁₃ - t ₁₄ in FIG. Erase discharge spots. Note that, at this time, no discharge spot exists in the discharge cell group of the first picture element adjacent to the write discharge cell. As a result, all the discharge cells are in a completely erased state, and especially regarding the picture element closest to the write discharge cell w, the wall charges on the dielectric layer are completely erased.

Therefore, when a discharge spot corresponding to the input information is generated in the write discharge cell in the next period t ₂₉ - t ₃₀ , the strong write discharge causes unnecessary discharge in the discharge cells d ₁ and a ₂ as described above. This eliminates the problem of electrical discharge.

Figure 6 shows a test panel in which a protective layer of magnesium oxide (MgO) is formed on a dielectric layer of alumina (Al ₂ O ₃ ) to explain the effect of the writing sequence (driving method) according to the present invention. An operating margin characteristic diagram is shown. As is clear from this figure, the maximum write voltage V _W max according to the present invention shown by the solid line B is lower than the maximum shift voltage V _S as compared to the conventional full write sequence shown by the dotted line A. The minimum shift voltage V _S increases from 120V to 150V in the max region and from 135V in the min region.
It has increased to 160V. Therefore, the minimum write voltage V _W
The operating margin for information writing corresponding to the difference from min is significantly increased compared to the conventional full write sequence.

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. For example, the shift operation inserted between the all-discharge cell lighting operation and the all-discharge cell erasing operation is not limited to one picture element, but may be performed for several picture elements, but as mentioned above, unnecessary discharge is caused by the first writing. Since this occurs only during discharge, one picture element is practically sufficient. 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.

As is clear from the above description, according to the present invention, it is possible to completely eliminate accidental erroneous discharges peculiar to self-shifting panels, and also to prevent unnecessary discharges and to suppress a decrease in the write operation margin. This can significantly improve panel quality. 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 of a self-shifting gas discharge panel to which the present invention is applied, and Figure 3 is drive voltage waveforms in a conventional full write sequence that prevents accidental erroneous discharges. 4 is a schematic diagram of the display state for explaining the occurrence of unnecessary discharge in the panel shown in FIG. 1, FIG. 5 is a diagram showing an example of the drive voltage waveform according to the present invention, and FIG. FIG. 6 is an operation margin characteristic diagram for explaining the effect of the drive voltage shown in FIG. 5; X1, Y1, X2 and Y2; bus terminal, Xij
and yij: electrode, aj to dj: discharge cell group, w: write discharge cell, P _W : write pulse, P _S : shift pulse, P _R : lighting pulse, Pe: erase pulse.

Claims (1)

[Scope of Claims] 1. A shift channel consisting of a periodic arrangement of a plurality of groups of shifting discharge cells determined by an electrode arrangement regularly connected to a plurality of bus bars, and one period of the discharge cell arrangement. In a self-shifting gas discharge panel having a configuration in which a write electrode corresponding to one picture element and defining a write discharge cell is provided at one end of the shift channel, an operation for generating a discharge spot to be displayed in response to input information. Prior to this, an all-lighting operation is performed to generate discharge spots in all discharge cells of the shift channel, and among the discharge spots generated by this all-lighting operation, some of the discharge cells in the discharge cell array of each cycle are After erasing each discharge spot, a shift operation for commonly shifting the remaining discharge spots to a position separated by at least one pixel, and a shift channel including the discharge cells in which the shifted remaining discharge spots exist. A method for driving a self-shifting gas discharge panel, characterized in that a full erasing operation is applied to all discharge cells.