JPS6161118B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new driving method that prevents erroneous discharge with a simple driving circuit configuration in a self-shifting gas discharge panel for multi-line display.

A self-shifting gas discharge panel sends information written in the form of discharge spots from the write-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. During this period, if the shift operation is stopped on a specific group of discharge cells, static display can be performed.Various types of display devices have already been proposed. In addition to display functions based on memory operation, such panels have the advantage of being smaller than display devices using ordinary cathode ray tubes, so they have recently been attempted to be used in various monitor displays and keyboard displays in computer terminal devices. ing. However, self-shift displays using such panels are mainly used for multi-line display, and by enabling independent shift operations for each line, it is possible to write or rewrite new characters in a selected display line, for example. The display contents in the remaining non-selected display rows can be held at a predetermined position while the selection is being performed.

By the way, when performing the above-mentioned shift operation, in the conventional self-shift type 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 the conventionally well-known matrix type panel, but is unique to self-shift type panels, and disrupts information within the panel and inhibits 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.

An object of the present invention is to provide a drive method that makes the write drive circuit configuration simple and inexpensive when applying the entire write sequence to the self-shifting gas discharge panel for multi-line display. It is. Briefly stated, this invention:
A plurality of shift channels having a periodic arrangement of a plurality of groups of discharge cells determined by a combination electrode arrangement of a row electrode in the same direction as the shift direction and a plurality of column electrodes periodically orthogonal to the row electrode are arranged in parallel. A plurality of display rows are provided, and each column electrode of each display row is commonly derived across each display row and connected to a plurality of bus bars, and the row electrode of each display row is connected to a plurality of bus bars. In a self-shifting gas discharge panel for multi-row display that was independently derived, an all-cell lighting drive circuit is connected to the bus bar of each column electrode, and a lighting selection circuit is connected to the row electrode of each row. When writing the first character information in the displayed display row, prior to the writing operation, the lighting selection circuit selects the display row in which the information is to be written and drives all the cells in the discharge cells included in the display row. an operation of generating discharge spots in all discharge cells in the selected row by applying a lighting pulse from a circuit;
The present invention is characterized in that an operation for extinguishing the discharge spot is added.

Preferred embodiments of the present invention will be described in more detail below with reference to the drawings.

First, before explaining the driving method, the structure of a self-shifting gas discharge panel for multi-line display equipped with a meander-type electrode structure to which the present invention is applied will be explained. FIG. 1 shows the electrode arrangement of such a panel. In this plan view, two shift channels SC1 and SC2 are representatively shown. These shift channels are arranged alternately on a lower substrate (not shown), and each has a common bus line Y.
1. Two Y (row) electrode groups y ₁ i and y ₂ i (i is a positive integer) with a meander-type pattern derived from Y2, and the inner surface of the upper substrate facing these Y electrode groups. Two Xs (columns) arranged alternately and derived to common bus lines X1 and X2, respectively.
It is configured between electrode groups x ₁ j and x ₂ j (j is a positive integer). Each electrode of the X electrode groups x ₁ j and x ₂ j is placed in a relationship such that it straddles two adjacent electrodes of the opposing Y electrode groups y ₁ i and y ₂ i, and the surface of each electrode is A dielectric material is coated on each substrate. Further, write electrodes W1 and W2 are provided for each channel adjacent to the rightmost electrode _x11 of one X electrode group and facing the rightmost electrode _y11 of one Y electrode group. However, in the opposing gap between each of the electrodes filled with discharge gas, there are 4
Depending on the combination of the two electrode groups, four groups of four-phase discharge cells ai, bi, ci, and di are arranged regularly and periodically, with one of the opposing electrodes alternately in common, resulting in a write discharge. It becomes possible to sequentially shift the discharge spots generated in the cells W along the arrangement of these discharge cells. Further details regarding the detailed structure and basic drive system of the self-shifting gas discharge panel equipped with the meander-type electrode structure as described above can be found in Japanese Patent Application No. 51-82410 assigned to the same assignee as the present application. It is stated in the book.

In this invention, as described above, a self-shifting type for multi-line display having a plurality of shift channels formed by adjacent discharge cells alternately arranging one opposing electrode in common with a regular repetition period. Gas discharge panels are the subject of a new drive method. FIG. 2 is a diagram schematically showing a panel for multi-line display in which multiple lines of shift channels are included in the same panel as representatively explained with respect to FIG. It has display lines. Each display line consists of seven shift channels in this case, and represents character information in a 5×7 dot pattern. Then, in order to enable the shifting operation of the discharge spot for each row, the two Y electrode groups are arranged for each row, respectively, Y11, Y12, . . .
...Y1n and Y21, Y22...Y2n are individually led out to two types of terminals. In addition, the two X electrode groups mentioned above are common to each row, X1 and X.
These terminals are respectively led out to terminals indicated by 2.

However, in such a self-shifting PDP for multi-line display, while a shift operation is being performed to write information in a selected display line, in order to improve the display quality of the information on the non-selected display line that has already been written, Information shifting method (SWAY) (operation)
It is configured so that it can be placed in a display state.

FIG. 3 is a drive voltage waveform diagram for achieving such shift operation and sway shift operation across a plurality of display rows. A case is shown in which display row SR1 is selected and second display row SR2 is in a non-selected state. In the same figure, A and B indicate the electrode voltage waveforms applied to the electrodes of the selected first display row and the unselected second display row through the indicated bus terminals, respectively, and C and D of FIG. 3 respectively A cell voltage waveform applied as a composite waveform of the voltage applied to the electrodes to the discharge cell group between the electrodes indicated in the first and second display rows is shown. As is clear from these figures, the shift operation of the meander-type gas discharge panel is such that four basic pulse trains, each indicated by ~, are sequentially rotated with respect to multiple bus lines in four unit periods _t0 to _t3 . This is done by distributing.

For example, referring to the unit period t ₀ , when the write pulse WP is simultaneously applied to the write electrodes w ₁₁ to w ₁₇ and w ₂₁ to w ₂₇ and a write voltage waveform as shown in the figure is applied to the write discharge cell w, A first discharge spot occurs in the written cell. At this time, A-phase discharge cells aj of shift channels SC ₁ j and SC ₂ j
Since the shift pulse SP as shown in the figure is applied, the pilot effect of the write discharge spot causes the first discharge cell a ₁ adjacent to the write discharge cell to
At the same time, discharge spots occur. As the application of the basic pulse train is switched in the next unit period _t1 , the discharge spot generated in the discharge cell _a1 becomes A1.
It is shifted to two adjacent discharge cells a ₁ and b ₁ of phase and B phase. In the case of the selected first display row SR1, these discharge spots are generated in the next unit period t ₂ , t ₃
As the basic pulse train as shown in the figure is applied, the two adjacent discharge cells b ₁ · c ₁ and c ₁ · d ₁ are sequentially shifted toward the other end along the shift channel SC ₁ j in a manner that they are shared. will be done. During this time, an erasing pulse EP is effectively applied to the discharge cell group whose discharge spot has been shifted based on the phase difference te between the pulses applied between the opposing electrodes, and the erasing operation of the discharge spot is performed. Ru.

However, in the case of the unselected second display line SR2,
In the next unit period _t2 , the basic pulse train applied to the Y-side bus bar is selected in an inverse relationship to that of the selected row SR1, so the discharge spots located in the discharge cells _a1 and _b1 are again D Phase and A phase discharge cell _a1 returns. In addition, in the next unit period _t3 , the D-phase and C-phase discharge cells are energized in the same way as in the selected row, but the discharge spot is transferred from the D- and A-phase cells to the rear D and C-phase cells adjacent thereto. continue to shift in the opposite direction. Due to such a sway shift operation, the write discharge spot generated along with the selected row due to the write operation is erased together with the application of the erase pulse EP to the cell _a1 at this timing. Note that if there are discharge spots written in advance in the discharge cells _d1 and _a2 of the non-selected row, these discharges can be removed by applying the pulse train according to the sway shift operation mode described above. The spot is a ₂・b ₂ →a ₂・d ₁ →
It is held while vibrating from side to side in a manner that shares two adjacent cells in the order of d ₁ and c ₁ . Regarding the above-mentioned sway shift method, Japanese Patent Application No. 57210-1985 assigned to the same assignee as the present applicant
Details are given in the specification.

As described above, this type of self-shifting panel for multi-line display performs writing and shifting operations of discharge spots corresponding to input information for a selected display row. However, such a self-shifting panel Based on the shifting operation of the discharge spot, abnormal wall charges are accumulated on the surface of the dielectric layer other than the normal discharge position, as shown by diagonal lines in the electrode arrangement diagram of FIG. The accumulated amount of 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

Now, the present invention is characterized in that such a writing method is effectively applied to a multi-line display panel, and FIG. 4 shows a main part block diagram of a self-shift display employing the writing drive circuit. shows. In this figure, 10 is a self-shifting gas discharge panel for multi-line display, and 20 is a keyboard which generates a character code data signal CCS and a write command signal STB corresponding to the character information to be written in response to the operator's operation. . A basic timing signal generation circuit 30 generates four basic pulse trains for shift operations and write operations, and a signal SNS indicating the number of shift operations. 40 is a timing switching circuit that performs write/shift operations in each display line;
In order to perform a sway shift operation and a stationary (fixed) display operation, the above-mentioned four
Outputs one basic pulse train in parallel on multiple lines.
50 is a control signal generation circuit, which generates the write command signal.
In response to STB and the signal SNS, each time character information is keyed in, a shift operation is enabled for each piece of information, and an all-cell lighting command signal FRS is generated.

60 is a row selection circuit which, in response to the row designation signal RSS,
A basic pulse train having the predetermined distribution order that enables a shift operation for a selected display row and a sway shift operation for an unselected display row is selected and supplied to the next Y-side shift drive circuit 71. .
The X-side shift drive circuit 72 receives a basic pulse train in a predetermined distribution order from the timing signal generation circuit 30. These drive circuits output shift pulses SP to the corresponding electrode buses. 80 is a write signal generation circuit, which generates the character code data signal.
Character pattern signals IF ₁ to _{IF 7} of 5×7 dots selected by the CCS are sequentially generated for 7 dots every 4 unit periods according to the predetermined pulse train. A write drive circuit 90 is commonly connected to the write electrode groups of each display row, and generates a write pulse WP corresponding to the character pattern signal from a driver corresponding to each electrode.

Reference numeral 100 denotes an all-cell lighting drive circuit which applies a lighting pulse PR to the X-side electrode bus common to each display row in response to an all-cell lighting command signal FRS from the control signal generating circuit 50, which will be described in detail later. Note that this pulse has a peak value V _R exceeding the discharge starting voltage.

In the above configuration, in order to prevent erroneous discharge during a character information writing operation to a selected display line, the following operation is performed prior to the writing operation. That is, FIG. 5 shows a drive voltage waveform diagram for the first display row SR1 when the row is selected. period
At t ₁ - t ₂ , the Y-side electrode bus line Y1 of the first display row
1 and Y21 are at the ground potential, and at the timing when the shift pulse SP is applied to the X-side electrode bus lines X1 and X2 common to each row, a lighting pulse as shown in the figure is generated.
Assume that PR is applied to the bus lines X1 and X2.
Then, the X electrode group x ₁ j, x ₂ j belonging to this bus line and the Y electrode group y ₁₁ i, y ₂₁ i of the first display row opposite to this electrode
Voltage waveforms as shown in VA to VD in the same figure are applied to the discharge cell groups a ₁₁ j to d ₁₁ j, respectively, and thereby the selected first display row SR
Discharge spots will occur simultaneously in all discharge cells included in one.

Note that when the lighting pulse PR is applied to the Y-side electrode bus lines Y12, Y22 to _Y1n , _Y2n of the remaining unselected display rows SR2 to SRn, a shift pulse SP is applied.
is applied, and therefore, due to the canceling effect of both pulses, no discharge occurs in the discharge cells of the row.

However, in the next period t ₂ - _{t 3} , when a shift pulse is applied with a phase difference between the X-side electrode bus line and the Y-side electrode bus line of the first display row, the cell group of each phase is erased. Pulse EP is applied, thereby erasing all discharge spots of all discharge cells in the first display row. After most of the abnormal wall charges on the discharge surface of the panel are removed by such a writing operation, the same character information writing operation as described in FIG. 3 is performed.

When selecting the second display row SR2 and performing a write operation for it, set the row designation signal RSS in FIG. Row selection circuit 60
Then, pulse trains such as those shown at Y11 and Y21 in FIG. 5 may be applied.

Note that between the all-cell lighting operation and the all-cell erasing operation, the discharge spot generated by the all-cell lighting operation is separated from the write discharge cell by two picture elements (a picture element consists of four cells a to d). If a shift operation is inserted to shift to a distant position, the abnormal wall charge can be completely and uniformly removed over the entire panel, which is more effective.

FIG. 6 shows specific examples of an all-cell lighting drive circuit and an X-side shift drive circuit, and an example of drive control pulses for these circuits. In the figure a, the all-cell lighting drive circuit 100 has a lighting voltage V _R
The main components are a transistor Q ₁ for controlling the supply of voltage, and a transistor Q ₂ for clamping the X electrode group to the shift voltage level when all cells are not lit. The shift drive circuit 72 includes a pulse transformer T ₁ and a transistor Q ₃ for controlling the rise of the shift pulse, a pulse transformer T ₂ and a transistor Q ₄ for controlling the fall of the shift pulse, and a group of X electrodes that are grounded when erasing a discharge. Transistor Q ₅ to clamp to level
It is mainly composed of. Note that I ₁ and I ₂ are inverters, B ₁ and B ₂ are buffer circuits, Vcc is an operating voltage source, _VR is a lighting voltage source, and Vsh is a shift voltage source.

For example, regarding b in the same figure, at time t ₁₁ the first
If a negative shift timing pulse Tp ₁ is input to the input terminal i ₁ , a positive pulse is generated on the secondary side of the pulse transformer T ₁ , causing the transistor
Q ₃ turns on. By this, the X electrode bus
A shift voltage Vsh is applied to 1 and X2, that is, the shift pulse SP rises. next time t ₁₄
When the negative shift timing Tp ₂ is applied to the second input terminal i ₂ , a positive pulse is generated on the secondary side of the pulse transformer T ₂ , turning on the transistor Q ₄ . As a result, the bus line is connected to the ground through the diodes D ₁ and D ₂ and the transistor Q ₄ , so that the bus line is at ground potential, that is, at the rising edge of the shift pulse.

By the way, at time t ₁₂ to t ₁₃ during the generation timing period of this shift pulse SP, a positive lighting timing pulse Tp ₃ is applied to the third input terminal i ₃ , thereby turning the transistor Q ₁ on and off. As a result, the lighting pulse voltage PR is applied to the bus bar.
(V _R ) is added. Therefore, a composite voltage pulse (VX in the figure) of the shift pulse and the lighting pulse appears on the bus lines X1 and X2. The timing of the generation of this pulse is delayed by 1 μs or more from the rise of the shift pulse to cause discharge to occur only in the first pulse of consecutive lighting pulses and not to cause discharge in subsequent pulses. In other words, by generating the shift pulse in advance of this shift pulse, unnecessary current consumption in the transistor _Q1 is suppressed.

On the other hand, the transistor _Q2 is connected to the bus line X1, for example, at the timing when the lighting pulse PR is not generated.
X2 is shifted voltage by external induction pulse
When it goes above Vsh, that voltage turns it on, thereby clamping the bus to the shifted voltage level. Further, the transistor _Q5 is turned on by inputting a negative timing pulse (not shown) from the fourth input terminal _i4 at the timing when the erase pulse EP shown in FIG. clamp to ground level.

As is clear from the above explanation, according to the driving method of the present invention, by using the most effective circuit configuration, the accidental erroneous discharge peculiar to self-shifting gas discharge panels for multi-line display can be completely eliminated, and the panel quality can be improved. can be significantly improved.

Incidentally, the writing method proposed earlier has a configuration in which a lighting pulse is applied to the Y electrode bus. Therefore, if this configuration were to be applied to a multi-line display, an all-cell lighting drive circuit would have to be provided for each display row, making the circuit configuration extremely complicated.

Therefore, it is extremely effective to apply the present invention to a self-shifting gas discharge panel for multi-line display.

[Brief explanation of the drawing]

FIG. 1 is an electrode layout diagram showing an example of a self-shifting gas discharge panel to which the present invention is applied, and FIG. 2 is a plan view schematically showing a display example when the panel in FIG. 1 is configured with multiple lines. , FIG. 3 is an example drive voltage waveform diagram for explaining the operation of the multi-row panel configuration shown in FIG. 2, FIG. 4 is a schematic system diagram of a self-shift display to which this invention is applied, and FIG. 5 is a diagram of the present invention. FIG. 6 is a diagram showing an example of the configuration of a drive circuit for generating the drive waveform shown in FIG. 5. X1, X2, Y1 and Y2: electrode busbar, xij
and yij: electrode, aj~dj: discharge cell group, SR1~
SR4: Display line, 10: PDP for multi-line display, 20:
Keyboard, 30: Basic timing signal generation circuit, 40: Timing switching circuit, 50: Control signal generation circuit, 60: Row selection circuit, 71 and 7
2: Shift drive circuit, 80: Write signal generation circuit, 90: Write drive circuit, 100: All cell lighting drive circuit, SP: Shift pulse, PR: Lighting pulse, WP: Write pulse, EP: Erase pulse.

Claims (1)

[Claims] 1 A plurality of shift channels having a periodic arrangement of a plurality of groups of discharge cells determined by a combination electrode arrangement of a row electrode in the same direction as the shift direction and a plurality of column electrodes periodically orthogonal to the row electrode are arranged in parallel. The column electrodes of each display row are commonly derived across the display rows and connected to the plurality of bus bars, and the row electrodes of each display row are connected to each display row. In a self-shifting gas discharge panel for multi-row display independently derived for each row, an all-cell lighting drive circuit is connected to the bus bar of each column electrode, and a lighting selection circuit is connected to the row electrode of each row, When writing the first character information to a selected display row, prior to the writing operation, the lighting selection circuit selects the display row in which information is to be written, and lights up all the discharge cells included in the display row. A self-contained display for multi-line display characterized in that by applying a lighting pulse from a drive circuit, an operation of generating discharge spots in all the discharge cells of the selected row and an operation of extinguishing the discharge spots are added. How to drive a shift type gas discharge panel.