JPS59204885A - Driving of gas discharge panel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for driving an AC gas discharge panel, and an object of the present invention is to provide a method for driving an AC gas discharge panel that can be driven at high speed and that does not cause deterioration in display quality even when driven at low speed.

Prior Art and Problems Compared to DC type panels, AC type gas discharge panels are characterized in that their electrodes are insulated. That is, as shown in FIG. 2(a), the X and Y electrodes 32, 34 are covered with insulating layers 36, 38, and there is a protective layer on top of these, although not shown.
They face each other with a gap 44 in between, and a mixed gas mainly consisting of neon is filled in the gap. 40: 42 is a substrate, at least one of which is a transparent plate, generally a glass plate. When a voltage is applied to the selected X and Y electrodes, a charging current flows through the intersection of the selected electrodes (this corresponds to the pixel), and gas emission is seen, but the positive and negative charges generated at this time are of opposite polarity. When it reaches the insulating layer of the electrode, its further progress is blocked by the insulating layer, and it stops adsorbed on the insulating layer as shown in the figure. When such an adsorbed charge (wall charge) 46 is generated, the electric field created by the electrode 32 34 in the gas discharge space 44 is canceled by the opposite electric field created by the wall charge, and an electric field is created in the space 44. When the battery runs out, the charging current stops and the light emission stops. Therefore, when the polarity of the voltage applied to the electrodes 32 and 34 is reversed, the wall charge is repelled by the electrode voltage, and in terms of electric field, the electric field due to the wall charge and the electric field due to the electrode voltage are added together, so that charging current flows even at a low electrode voltage. Gas luminescence can be seen. This state ends when wall charges are adsorbed, contrary to the previous case, but if the voltage applied to the electrodes 32, 34 is alternating current, the polarity reversal is repeated at a predetermined period, and continuous light emission occurs.

If there is a wall charge 46, a current will flow and light will be emitted even if the electrode voltage is a low voltage, for example 90V, but in the initial state where there is no wall charge, no current will flow and no light will be emitted unless a high voltage, for example 140V, is applied. The above-mentioned high voltage is called a write voltage, and the above-mentioned low voltage is called a sustain voltage, and it is said that there is a wall charge and a memory function.

To erase the memory, it is sufficient to eliminate the wall charge, and this is accomplished by applying narrow pulses of opposite polarity to the electrodes 32,34. In the illustrated state, positive electrode 34, electrode 3
When a negative voltage is applied to 2 for a short period of time, positive and negative wall charges are released from the surface of the insulating layer into the gas discharge space, and the electrode voltage disappears without reaching the insulating layer on the opposite side, ending the repulsive action. Therefore, the two are left in a mixed state, combine and disappear.

The emission brightness of this gas discharge panel is determined by the frequency, and while CRT displays have the problem that the brightness decreases as they get larger, gas discharge panels do not have this problem and are characterized by the ability to create bright large screens.

However, when a gas discharge panel with certain characteristics is used with a CRT interface, the following problems arise. That is, C
RT refreshes the screen at a rate of 60 frames per second, so even if the display is a gas discharge panel, it must do so. However, gas discharge panels take a long time to write, especially on large screens, so CR
I can't keep up with T's fresh speed. Therefore, frames have to be dropped, but in the conventional method, one line is erased all at once and then one line is rewritten at the same time. There is a problem with being noticeable. However, each CRT screen is rewritten repeatedly at high speed, and there are cases where there is little or no difference from the one before and after it.
If the screen or pixels do not change, there is no need to rewrite them.

If a method is adopted in which pixels that do not change are not rewritten, screen flickering can be significantly reduced. A simple way to perform such control is to install a memory that stores the screen data from the previous screen, and
A comparator compares the pixel data of the previous screen read from the memory with the pixel data of the current screen, and if they match, no rewriting is performed, and if they do not match, rewriting is performed. Requires hardware such as a comparator.

Purpose of the Invention The present invention provides a driving method that rewrites only the pixels that have changed, and leaves the pixels that have not changed, without using memory or comparators, by changing the driving voltage waveform of the gas discharge panel. That is.

Structure of the Invention The present invention provides a method for driving an AC gas discharge panel that is equipped with a large number of X and Y electrodes, and performs scanning image display by selecting a line with the Y electrode and selecting pixels on the line with the X electrode. “1” of the line to be updated.

When receiving “0” image data, the data emits “1”
A write voltage pulse is applied to the electrode, and the data is set to non-emission “0”.
An erasing pulse is applied to the X electrode of ``, and a voltage pulse is applied to the Y electrode corresponding to the line to make the pixels on the line emit or not emit light according to the image data.After that, a sustain voltage pulse is applied to both electrodes. The present invention is characterized in that a sustain voltage pulse is applied to the Y electrodes corresponding to added and non-updated lines, which will be described in detail below with reference to the drawings.

Embodiment of the Invention When the gas discharge panel is used with a CRT interface, for example, the Y electrode 34 in FIG. 2+al is used as a horizontal scanning line,
The X electrodes 32 define each pixel on the horizontal scanning line, and 1947 minutes of video signals are taken into a register (not shown) having a number of bits equal to the number of electrodes 32. A signal is given to each of the lines to perform simultaneous writing for one line. By providing the same number of Y electrodes 34 as the number of horizontal scanning lines of a CRT and performing the same operation for each Y electrode 34, a screen similar to a CRT screen can be displayed.

Writing is performed by applying a high voltage of about 140 V, and in the conventional method, before that, one line is erased all at once, and this is shown as a drive waveform as shown in FIG. 2 (bl).

That is, the pulse E of Yj in this figure is the erase pulse waveform,
This is given to the Y electrode 34, and the X electrode 32 is given Xi
When a sustaining voltage pulse of
, 34 is as shown in the figure X1-yj, and if the intersection is once in a light-emitting state (written), light emission will be seen at each rise and fall, and it will be erased. Pulse E causes insufficient ignition and the wall charge disappears, and after that the period T
As shown in C, no light is emitted even if a sustaining voltage is applied. On the other hand, if the intersection is not written, no light will be emitted even if a sustain voltage is applied. Furthermore, if there is no voltage pulse P1 to the X electrode 32 before the erasing pulse E is applied in period TB, the intersection point is
There is only a wall charge generated during light emission with a sustaining voltage pulse (applied to the electrode), and even if an erasing pulse E is added to this, there is no repulsion or movement of the wall charge, and no erasing is performed. Writing is performed by applying write voltage pulses W1. to X and Y electrodes as shown in period TD. This is done by adding W2. Pulse Wl,
When W2 is added at the same time, W1 + W2 = W3 at the intersection
A large voltage of =140V is applied, and the intersection portion emits light (becomes a written state).

In the conventional method, immediately before writing or rewriting each line, an erase pulse E is applied to the Y electrode 34 corresponding to the line, the entire line is once erased, and then all X
Input one line of 1°0 image data into the electrode 32, and set the input value to 1.
The intersection of the electrode with the Y electrode was made to emit light (write). On the other hand, in the present invention, simultaneous erasure is not performed,
1 is written and 0 is written according to the 1,0 image data of the line.
is erased, and this is done simultaneously for all pixels on the line.

Driving waveforms for performing this operation are shown in FIGS. 3 and 4.

FIG. 3 shows the voltage pulse waveform applied to each electrode, where Yj is the pulse waveform applied to the selected Y electrode 34, Ym (j is the pulse waveform applied to the unselected Y electrode 34, and Xw is the voltage pulse waveform applied to the unselected Y electrode 34, is 1) and XE is the pulse waveform applied to the X electrode 32 (where the input data is 0), and XE is the pulse waveform applied to the X electrode 32 (where the input data is 0). The voltage at the intersection is the difference between the voltages of the two electrodes, as shown in Figure 4.At each intersection (S element), light is emitted when the voltage rises to +H and falls, and at the portion P3, it is H-90V. Since the voltage exceeds the sustaining voltage (140 V), even the non-emitting intersections emit light, resulting in a write state.

Therefore, if a sustaining voltage is applied thereafter, the light will continue to emit light. Part P4
In this case, insufficient light is emitted, the wall charge disappears, and no light is emitted even if a sustaining voltage is applied thereafter. Note that the write/erase cycle in FIG. 3 is 30 to 50 KHz.

In this way, according to the present invention, the pixel is forcibly centered at 1.0 of the input image data in accordance with i, o- of the input image data. The previous state was 1 or 0, so there are four combinations with the current data: 11, 10, 01°00. However, if the current data is 1, it is rewritten to 1 even if the previous data is 1.0 ( For details, if it is 1, leave it as is, if it is 0, rewrite it to 1)
, if the current data is O, it is rewritten to 0 even if the previous data was l or o. XW-X j, XE-Y j in Figure 4
These are possible with the following waveforms. Xw-XmSj in Figure 4
The waveforms of , can be maintained. That is, since a voltage exceeding +H and a narrow pulse are not applied, neither writing nor erasing can be performed. Since writing and erasing can be performed simultaneously, double high-speed display is possible even with the same driving frequency.

FIG. 1 shows the drive section of the gas discharge panel, 10 is a control circuit, 20 is a gas discharge panel, 14.18 is a line driver thereof, 12.22 is a logic integrated circuit, and 16 is a sustain driver. Also V cy.

Hcy is vertical, water buffalo synchronization signal, CLK is clock, DA
TA is image data. These operations are known.

As described in detail, according to the present invention, if each pixel changes from the previous screen, it is rewritten, and if there is no change, it is left as it is, and - simultaneous erasure and rewriting are not performed, so there is less screen flickering (and high speed It is now possible to display large screens, and the screen quality does not deteriorate even at low speeds such as 10 to 5 screens per second, and various functions such as scrolling and blanking are fully satisfied. It is possible to display the following information.

Therefore, a low-speed integrated circuit can be used for the control circuit, and power consumption can be reduced. In addition, such rewriting can be done by simply changing the waveform, and there is an advantage that no special screen memory or comparator is required.

To connect to a device with a conventional CRT interface, an interface circuit that samples only one screen out of several screens can be added. By simultaneously writing and erasing and writing at 10 times/second, the frequency of the control circuit can be reduced to 1/12, or a large panel with 12 times the number of scanning lines can be displayed using a CRT interface using an integrated circuit with the same speed. It becomes possible to do so.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the driving section of the gas discharge panel, FIG. 2 is an explanatory diagram of the configuration of the gas discharge panel and its driving voltage waveform, and FIGS. 3 and 4 are driving voltages according to the method of the present invention. FIG. 3 is a waveform diagram showing waveforms. In the drawing, 32 is an X electrode, 34 is a Y electrode, 20 is a gas discharge panel, Pi, P2 are sustaining voltage pulses, W3. P3 is a write pulse, E2. 'P4 is an erase pulse. Applicant Fujitsu Limited Representative Patent Attorney Minoru Aoyagi 678

Claims (1)

[Claims] In a method for driving an AC gas discharge panel that is equipped with a large number of X and Y electrodes, the Y electrode selects a line, and the X electrode selects pixels on the line to perform scanning image display. Upon receiving the "1" and "0" image data of the line to be updated, a write voltage pulse is applied to the X electrode whose data emits light "1", and an erase pulse is applied to the X electrode whose data is non-emissive "0". is applied to the Y electrode corresponding to the line, and the pixels on the line are made to emit or not emit light according to the image data.After that, a sustaining voltage pulse is applied to both electrodes, and a voltage pulse is applied to the non-updated line. A method for driving a gas discharge panel, characterized in that a sustaining voltage pulse is applied to a corresponding Y electrode.