JPS648349B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a method for driving an AC driven gas discharge panel, and in particular to a new write addressing method for a surface discharge gas discharge panel with internal selection logic functionality. It is related to.

(b) Prior Art and Problems A type of gas discharge panel known as a plasma display panel is a surface discharge type panel. As one improvement of this type of panel, Japanese Patent Application Laid-Open No. 57-78751 discloses that a write discharge cell (write cell) and a sustain discharge cell (display cell) are provided separately, and the sustain electrode that constitutes the display cell is A panel in which pairs were connected in a matrix to provide a selection logic function to the display cells inside the panel was developed in Japanese Patent Laid-Open No. 57-
Proposed in No. 78751.

However, when driving this type of panel, a major problem is how to accurately and quickly draw the write discharge generated in groups to desired display cells. In the conventional method, display cells were selected by combining complex write and erase operations in groups, which reduced the number of elements in the external drive circuit, but address control was complex and slow, and there was insufficient It was difficult to secure an operating margin.

(c) Purpose of the Invention In view of the above-mentioned circumstances, the present invention aims to improve the write address method for a surface discharge type gas discharge panel equipped with an internal selection logic function. This is an attempt to speed up the write address and expand the operating margin by automatically erasing unnecessary cells among the write cells that have been discharged in groups.

(d) Structure of the Invention In order to achieve the above object, the driving method of the present invention includes a plurality of pairs of sustain electrodes arranged adjacently in parallel in pairs on one substrate defining a gas-filled space; A plurality of write electrodes are arranged insulated in a direction crossing these sustain electrodes, and one sustain electrode of each pair is connected to a bus line for each group by forming a plurality of adjacent sustain electrode pairs into a group. In a gas discharge pulse in which alternating sustain voltage pulses are applied to one electrode and the other sustain electrode, when generating a discharge in the display cell of a selected sustain electrode pair,
After applying a write voltage pulse to the intersection of the write electrode adjacent to the selected display cell and one of the electrodes connected to the bus bar to generate a write discharge in groups in the write cells corresponding to the intersection of these electrodes, The application timing of the sustain voltage pulse is controlled between the selected electrode and the non-selected electrode for the other independent plurality of sustain electrodes, and the selection is maintained at a time close to the falling edge of the write voltage pulse. The present invention is characterized in that a sustaining voltage pulse applied to the electrode causes a selected display cell adjacent to the written cell to generate a discharge that takes over the discharge of the written cell.

(e) Embodiment of the Invention Hereinafter, an embodiment of the present invention will be described in more detail with reference to the drawings.

FIG. 1 and FIG. 2 are a cross-sectional view of a main part and a plan view of electrode arrangement showing an example configuration of a surface discharge type gas discharge panel to which this embodiment is applied, in which a lower glass substrate functions as an electrode support substrate. A plurality of pairs of sustain electrodes 11 are arranged in the vertical direction on 10,
A write electrode 13 extending laterally through an insulating layer 12 made of low melting point glass and a separator electrode 14 used in a floating state are provided thereon. On top of the upper write electrode and separator electrode are several thousand Å made of magnesium oxide (MgO).
A gas space 17 surrounded by an upper glass substrate 16 for a cover is provided above the surface layer 15 .

A sustain electrode pair typically designated by numeral 11 is a second sustain electrode pair.
As is clearer from the figure, two adjacent sustain electrodes X1, Y1, X2, Y2 are formed as a pair, and each sustain electrode pair has discharge portions x and y widened so as to be close to each other. And this discharge part x
Write electrodes W1 and W2, typically indicated by reference numeral 13, are provided in a relationship that crosses positions close to and y,
A separator electrode 14 in a floating state is provided along the write electrode on the side away from the discharge section. Thus each write electrode W1, W2
A write cell Wc is formed corresponding to the intersection of one of the sustain electrodes X1 and X2, and a display cell Dc is formed corresponding to the adjacent discharge portions x and y of each pair of sustain electrodes.

In addition, in the above electrode configuration, in order to simplify the address circuit for selecting each display cell, all the sustain electrode pairs are divided into a plurality of groups, and one sustain electrode is commonly connected for each group. Furthermore, a configuration is adopted in which the other sustain electrode is commonly connected to the electrodes of the same rank in each group to provide an internal selection logic function. The present invention relates to an addressing method for such a surface discharge panel with a selection logic function, and will be explained below using FIG. 3.

Figures 3a, b, c, d, and e are representations of a 9×5 dot configuration in which nine sustain electrode pairs are grouped together, one sustain electrode is commonly connected, and the other sustain electrode is individually derived. FIG. 4 is a diagram showing a selected state of discharge cells corresponding to a write operation procedure when displaying the letter "A" using a panel as an example. First, Figure 3a
If one of the sustain electrode groups X1 to X9 and the write electrode W1 of the first line, which are commonly connected to the bus line X, are selected and a write voltage exceeding the discharge starting voltage is applied between them as shown in FIG. A write discharge as shown with a circle is generated in the write cells Wc of the corresponding group. Next, as shown in Figure 3b,
When the other sustain electrodes Y4 to Y9 are selected and a sustain voltage is applied, a discharge is drawn into the display cell Dc at the point marked with a double circle and stored. After the writing of the first line is completed in this way, one of the sustain electrode groups X (X1 to X9) is
and the second line write electrode W2 are selected to generate a discharge in the write cells in groups indicated by circles, and then the other necessary sustain electrode group Y3,
By selecting Y5 and applying a sustain voltage, a discharge can be generated in the desired display cell indicated by the double circle. After writing on the third to fifth write lines in the same manner, a unit storage operation is performed on the other desired sustain electrode group to write the information of the entire screen, as shown in FIG. 3e. The desired letter "A" as shown is displayed in a discharge dot pattern.

One of the features of this invention is the line addressing method in group units as described above, but in this case, by devising the voltage waveform applied to the sustain electrode pair, it is possible to address the problem in the write discharge generated in line units. The operation for erasing unnecessary written cells can be omitted.

That is, FIG. 4 is a diagram showing an example of such a driving voltage waveform, where Ws is the voltage waveform applied to the selected write electrode, Xs is the voltage waveform applied to one selected sustain electrode group, and Ys is the voltage waveform applied to one selected sustain electrode group. indicates the voltage waveform applied to the other selected sustain electrode, and Yn indicates the voltage waveform applied to the other unselected sustain electrode. In addition, SWc in the figure indicates the voltage waveform applied to the selected write cell as the composite voltage of Ws and Xs,
SDc represents a voltage waveform applied to a selected display cell as a combined voltage of Xs and Ys, and NDc represents a voltage waveform applied to a half-selected display cell as a combined voltage waveform of Xs and Yn.

As is clear from FIG. 4, one and the other electrode of each sustain electrode pair usually have a peak value of Vs.
Negative-polarity sustaining voltage pulses SP are applied alternately and periodically. Now, for example, the other sustain electrode group Y1 to Y9 is at ground potential, and one sustain electrode group X (X1 to X9) is connected to the sustain voltage pulse.
When a positive write voltage pulse WP with a peak value Vw is applied to the selected write electrode W1 with SP applied, the write cells Wc in groups corresponding to each intersection between this write electrode and one sustain electrode group A discharge occurs, and along with this, wall charges accumulate on the MgO surface layer 15, and a wall voltage VQ as shown by the dotted line in the waveform diagram SWc is generated. When this write voltage pulse WP rises and the potential difference between the electrodes becomes zero, a re-discharge occurs due to the previously generated wall voltage VQ itself, and the space charge caused by this re-discharge serves as a ignition, and the other A fourth pulse is applied to the selected display cell to which a sustain voltage pulse SP is selectively applied between the sustain electrode and the sustain electrode.
It is possible to generate a display discharge accompanied by a wall voltage VQ as shown at SDc in the figure. Of course, in this case, since the write cell and the display cell share one sustain electrode, the wall charge (electrons) attached to the one sustain electrode due to the write discharge spreads to the display cell side and is initially It also acts to help generate display discharge. Therefore, the transition of the discharge from the write cell to the display cell utilizes the combination of both the space charge caused by the re-discharge at the fall of the write pulse in the write cell and the wall charge during the write discharge.

Therefore, in this invention, the waveform diagram Ys in FIG.
As shown in SDc, regarding the application timing of the sustain voltage pulse SP to the other sustain electrodes Y1 to Y9 at the falling edge of the write voltage pulse WP, the write voltage pulse is applied to the selected sustain electrode (for example, Y4 to Y9). It is set to approximately match the falling edge of WP, and the unselected sustain electrodes Y1 to Y3 are set to be temporally separated from the falling edge. Specifically, this can be achieved by making the application timing of the sustain voltage pulse to the sustain electrodes earlier than the original application time (see the dotted line pulse in the waveform diagram Ys) to the selected sustain electrodes. In this manner, the first discharge occurs in the selected display cell in accordance with the timing of re-discharge due to the potential difference of the wall charge itself of the write cell.

On the other hand, when writing to the selected display cell is performed in this way, the sustain voltage pulse SP is not applied to the non-selected display cells in the same group at the falling edge of the write pulse, as shown by NDc in Figure 4. ing. Therefore, in the non-selected display cell, the wall charge generated by the write discharge is automatically erased by re-discharge due to the wall voltage itself at the fall of the write voltage pulse WP, and a special erase operation is required. There is no. To perform such self-erasing, sufficient wall charge is generated to cause self-discharge with the first write voltage pulse WP, and then it is applied to non-selected display cells after the fall of the write pulse. It is only necessary to temporarily omit the sustaining voltage pulse SP or delay its application timing.

Let us now explain in a little more detail the phenomenon of self-recurring discharge caused only by wall voltage as described above. FIG. 5a is a cross-sectional view of the structure of the write cell section taken along the line -' in FIG. 2. When the write electrode W2 side is made positive and a write voltage pulse as described above is applied, a write discharge occurs After that, electrons and ions adhere to the MgO surface layer 15 with polarity as shown in the figure, forming wall charges. Then, when the write pulse falls and the write electrode W2 and the sustain electrode X1 become at the same potential, the potential distribution on the surface layer 15 becomes dependent only on the wall voltage. Figure 5b shows the change in surface potential during this period. Curve A is the potential distribution depending on the electrode potential when the writing voltage is applied before discharge, and dotted line B is the potential distribution depending on the electrode potential due to the wall charge caused by the first discharge. Curve C shows the potential distribution due only to the wall charges after the electrode potential is removed. However, self-discharge occurs when the potential difference VQ' of the wall charges exceeds the discharge voltage Vf, and the generation of such wall charges mainly depends on the rising waveform of the write voltage pulse and the structure of the panel. Particularly in the panel configuration shown in FIG. 1, the thickness of the surface layer 15 is greatly related to the amount of wall charge generated, and if the surface layer is too thick, the surface potential distribution becomes gentle and self-discharge occurs. It is difficult to create a wall charge potential difference that would cause . However, if the surface layer 15 is a vapor-deposited film of only MgO,
When formed thinly with a thickness of about 5000 Å, the potential distribution on the surface changes sharply corresponding to the electrode boundary, and the potential distribution of the wall charge also changes sharply to reflect this. As a result, self-discharge due to an avalanche phenomenon is more likely to occur in the potential change region, and the thinner the surface layer is, the more effective this is. According to experiments by the inventors, sustain electrode pair 1
When the thickness of the dielectric layer 12 covering the surface layer 1 was 10 μm, it was confirmed that a self-discharge phenomenon occurred at the fall of the write pulse in a range where the surface layer thickness was 1 μm or less. As an example, the write pulse used at this time had a peak value of 110 V and a duration of 8 μs.

In addition, in the above panel configuration in which the write electrode is disposed on the upper layer of the sustain electrode pair and covered with a thin surface layer, the protection on the write electrode is inevitably weak, so strong discharge during writing may occur. There is a risk that the surface layer will be damaged. In order to prevent such a problem, it is preferable to apply the polarity of the write voltage pulse in a direction in which the write electrode side is positive so that the write electrode is not bombarded by ions during discharge.

As described above, the discharge is selectively transferred from the write cell to the display cell by using the initial discharge accompanied by the generation of wall charges when the write voltage pulse is applied and the re-discharge caused by the wall charges themselves. According to the driving method of the present invention, a sufficient operating margin of a surface discharge panel with a selection logic function can be ensured. Incidentally, the dot pitch between display cells is set to 0.5mm.
In a 16 x 24 dot panel, a maintenance voltage margin of 15V can be obtained from 115V to 130V.
Moreover, the margin of the write voltage that is combined and added to this sustain voltage was approximately 15V from 105V to 120V.

(f) Effects of the Invention As is clear from the above description, according to the driving method of the present invention, the write cell and the display cell are separated, and at least one of the sustain electrode pairs constituting the display cell is grouped with one electrode. Targeting surface discharge type gas discharge panels that are commonly connected in units and have an internal selection logic function, there is no need for selective erasing operations during writing, and address control is simple and high-speed address writing is possible. In addition, a sufficient margin for write operations can be ensured, resulting in great practical effects.

[Brief explanation of the drawing]

Figure 1 is a sectional view of the main parts of a surface discharge type gas discharge panel to which the present invention is applied, Figure 2 is a plan view showing the main part configuration of the electrode arrangement, and Figure 3 corresponds to the procedure of the writing operation according to the present invention. FIG. 4 is a diagram showing an example of the drive voltage waveform; FIG.
The figure shows the potential distribution on the panel surface layer. In the figure, 10 is a substrate, 11 is a pair of sustain electrodes,
12 is an insulating layer, 13 is a write electrode, 14 is a separator electrode, 15 is a surface layer, 16 is a cover glass substrate, 17 is a gas space, X1 and X2 are one sustain electrode, Y1 and Y2 are the other sustain electrode, W1 and W2 is a write electrode, Wc is a write cell, and Dc is a display cell.

Claims (1)

[Claims] 1. A plurality of pairs of sustain electrodes arranged in parallel and adjacent to each other in pairs on one substrate defining a gas-filled space, and arranged insulated in a direction crossing these sustain electrodes. A plurality of write electrodes are provided, a plurality of adjacent sustain electrode pairs are grouped, and one sustain electrode of each pair is connected to a bus line for each group, and an alternating sustain voltage is applied between one sustain electrode and the other sustain electrode. In a gas discharge panel to which a pulse is applied, when generating a discharge in a display cell of a selected sustain electrode pair,
After applying a write voltage pulse between the write electrode adjacent to the selected display cell and one of the electrodes connected to the bus bar to generate a write discharge in groups in the write cells corresponding to the intersection of these electrodes, The application timing of the sustain voltage pulse is controlled between the selected electrode and the non-selected electrode for the other independent plurality of sustain electrodes, and the selection is maintained at a time close to the falling edge of the write voltage pulse. A method for driving a gas discharge panel, characterized in that a sustaining voltage pulse applied to an electrode causes a selected display cell adjacent to the written cell to generate a discharge that takes over the discharge of the written cell. 2. The method of driving a gas discharge panel according to claim 1, wherein the write voltage pulse is a pulse voltage having a polarity that is relatively positive on the write electrode side. 3. According to claim 1, the write voltage pulse applied to the write electrode is a positive polarity pulse voltage, and the sustain voltage pulse applied to the sustain electrode pair is a negative polarity pulse voltage. How to drive a gas discharge panel.