JPS6226134B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the pilot lighting method in an AC-driven gas discharge display device for matrix display.

As is well known, this type of matrix type gas discharge display panel has an X electrode and a Y electrode, each supported on a glass substrate and arranged to face each other so as to intersect with each other, and a discharge gas space sealed between them. It has a structure insulated from the ground by a dielectric layer. Then, an alternating sustaining voltage pulse V _S as shown in FIG. 1, for example, is applied between the X and Y electrodes, and a write voltage pulse V exceeding the discharge starting voltage V _F is shifted in phase with (or in synchronization with) this pulse. When _W is applied as a combined voltage from the selected X and Y electrodes, the discharge cell defined at the intersection of the electrodes discharges and emits light. Due to the discharge caused by this writing voltage pulse, a wall voltage is generated on the inner wall of the electric layer of the discharge cell according to the polarity of the applied voltage at this time, and this wall charge exhibits a wall voltage V _Q as shown by the dotted line in the figure. remain in form. Then, in the next half cycle of the sustaining voltage pulse V _S , the voltage difference between the wall voltage V _Q and the sustaining voltage V _S exceeds the discharge starting voltage V _F , causing a discharge again, and from then on, such a discharge is maintained alternately. Repeatedly every half cycle of the voltage pulse, the information once given in the form of the write voltage pulse V _W is stored in the form of wall charges and maintained by the alternating sustain voltage pulse.

On the other hand, when a narrow erase voltage pulse V _E is applied to a discharge cell that maintains a memory state, discharge light is generated once but the wall voltage V _Q is not generated, and then a sustain voltage pulse is applied. Also, no discharge is generated, and therefore the display of information can be erased.

By the way, in such a gas discharge display panel, in order to improve the discharge delay characteristic peculiar to gas discharge display elements, a specific discharge cell is always turned on as a pilot discharge cell in order to facilitate the start of discharge. Fig. 2 shows a configuration diagram of an example of a conventional gas discharge display device equipped with such a pilot discharge means. In the figure, 1 is a matrix type gas discharge display panel. , a plurality of display X electrodes 11 and a pilot flame X electrode 12
An upper glass substrate 13 is formed by covering a plurality of display Y electrodes 14 and a pilot Y electrode 15 with a dielectric layer. , and these glass substrates 1
3 and 16 are arranged facing each other with a predetermined gas discharge space interposed therebetween. 2 and 3 are sustaining voltage pulse generation circuits, and the display X and Y electrode group 1
1 and 14 are supplied with a sustaining voltage pulse V _S (peak value +90 V) as shown in FIGS. 3a and 3b. 4 and 5 are individually addressable write voltage generation circuits, and in order that their combined voltage waveform corresponds to the write voltage pulse V _W shown in FIG. 1 write voltage V _W1 (see FIG. 3 c) and a negative polarity second write voltage V _W2 (peak value -60 V) shown in FIG. 3 d are generated from the circuit 5, respectively. It is selectively supplied to the X and Y electrode groups 11 and 14, respectively.

6 and 7 are pilot voltage pulse generation circuits, which consist of two switching transistors connected in series.
When the input signals _{A 1 ,} B ₁ and A ₂ , B ₂ shown in FIG. 3 are applied to the two input terminals _6a , 6b and 7a, 7b, the transistors are alternately switched. Its connection points P ₁ and P ₂
A voltage pulse train for pilot fire discharge as shown in FIG.

2 and 3, the intersection of the pilot flame X electrode 12 and the display Y electrode 14, and the intersection of the pilot flame Y electrode 15 and the display X electrode
The discharge cells for the pilot fire each determined at the intersection of 1,
The composite voltage pulse waveform shown in Figure 3g and h will be applied, and its peak voltage (V _W1 +V
_W2 ) reaches a maximum of about 150V, and the first discharge spot for the pilot flame occurs as shown by the black circle in Figure 2.
This discharge spot is maintained by a subsequent train of voltage pulses. In other words, the pilot discharge cell is always lit until the device is powered off. In the lighting state of such a pilot discharge cell, "A"
When the composite voltage pulse waveform shown in FIG. The address display cell immediately lights up due to the supply of the initial charge generated by the discharge of the pilot cell. This discharge spot group "A" indicated by a black circle in FIG. 2 is maintained by sustaining voltage pulses V _S which are alternately and repeatedly applied.

On the other hand, the pilot fire discharge cell (hereinafter referred to as the starting pilot fire discharge cell) defined at the intersection of the pilot fire X electrode 12 and the pilot fire Y electrode 15 to which the composite voltage pulse waveform shown in FIG. 3j is applied, High-intensity discharge spots are constantly generated due to the highest electric field applied. Therefore, the lighting operation of the pilot discharge cell, which is determined at the intersection of the pilot electrode and the display electrode, can be made faster, which is extremely effective in improving the discharge delay characteristics.
On the other hand, there are the following problems, and in practical use it must be placed outside the display surface (Japanese Patent Laid-Open No. 52
69262), therefore, no improvement in the discharge delay in the pilot discharge cell could be expected.

That is, the high-intensity pilot discharge light becomes an eyesore and makes the display discharge light relatively inconspicuous, thereby substantially degrading the display quality. In addition, since the voltage level applied to the starting pilot cell is too high, it deteriorates the surface of the dielectric layer corresponding to the cell, and due to this deterioration, the discharge voltage at the electrode intersection increases, and the dielectric layer that is sputtered increases. There is a problem in that the wall surface components adhere to nearby display discharge cells and induce characteristic fluctuations of the display discharge cells. Therefore, in order to solve this problem, resistors R ₁ and R ₂ are inserted into the pilot voltage pulse generation circuits 6 and 7 for current limiting, but the resistance value is excessively increased and the pilot voltage pulse generator X , when the discharge current at the intersection of the Y electrodes is set to the optimum magnitude, the discharge current at the intersection of the pilot electrode and the display electrode, which are in the optimal state, is excessively restricted, and only a portion of the pilot discharge cells are lit. There is a new problem in that the pilot discharge cells either fail or all the pilot discharge cells stop lighting. In view of these problems, in practice, the values of the resistors R ₁ and R ₂ are set so that the discharge current at the intersection of the pilot flame electrode and the display electrode is optimized, and the values of the pilot flame X, The intersection of the Y electrodes is positioned at the sealing area 8 of the pair of glass substrates, as shown in FIG. Therefore, conventional gas discharge display devices have the disadvantage that there is often a time delay between when the power is turned on and when the first pilot discharge occurs at the start of operation of the device.

This invention was made in view of the above-mentioned conventional situation in order to shorten the time delay in the generation of pilot discharge without deteriorating the display quality. It is possible to arrange a starting pilot discharge cell by the intersection of the X and Y electrodes for the pilot flame in the vicinity of the discharge cell, and specifically, the pilot fire discharge cell can be placed adjacent to the side of the X electrode (or Y electrode) for the pilot flame. Y of
In addition to providing an X electrode (or Y electrode) for the starting pilot flame so as to intersect with the electrode (or X electrode),
The present invention is characterized in that these electrode intersections are configured in the shape of an enormous electrode, and the starting pilot X electrode (or Y electrode) is connected to a pilot voltage pulse generation circuit via a current limiting circuit. Therefore, the lighting of the pilot discharge cell is instantaneously established by the initial strong discharge in a relatively large area of the starting pilot discharge cell, and the display discharge light is reduced by the subsequent weak discharge. It provides good visibility.

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

FIG. 4 shows the electrode configuration and pilot voltage pulse generation circuit configuration of a gas discharge display panel according to one embodiment of the present invention. Note that the sustain voltage pulse and write voltage generating circuits are omitted, and the same parts as in FIG. 2 are denoted by the same reference numerals. In this figure, a portion of the pilot flame X electrode 12 is extended as shown, and a rectangular electrode piece 21 is provided at the tip of the extended portion 12a. In addition, an independent second pilot Y electrode 22 is provided above and adjacent to the pilot Y electrode 15, and a rectangular electrode piece 23 facing the electrode piece 21 is provided at the tip of the Y electrode 22. ing. A starting pilot discharge cell is formed at the intersection of the electrode pieces 21 and 23. A current limiting circuit 24 is also connected to the second Y electrode 22 for the pilot flame, and the other end of the circuit 24 is connected to the connection point P ₂ between the resistors R ₁ and R ₂ in the pilot flame voltage pulse generation circuit 7. Connecting. The current limiting circuit 24 is not limited to the resistor _R3 as shown in the figure, but may also be a parallel circuit of a resistor and a capacitor.

FIG. 5 shows a drive waveform diagram for explaining the effect of the current limiting circuit 24, in which a is a voltage waveform applied to the pilot flame X electrode 12, and b is a voltage waveform applied to the pilot flame Y electrode 15. Waveform, c is for the second pilot flame
d and e are the voltage waveforms applied to the electrode 22, and d and e are the cell voltage waveforms and discharge currents that are applied to the cell as a composite voltage when a temporary discharge cell is defined between the pilot X and Y electrodes 12 and 15. Waveform,
f and g respectively indicate the cell voltage waveform and discharge current waveform applied as a composite voltage to the starting pilot discharge cell determined by the intersection of the two electrode pieces 21 and 23.
As is clear from FIG. 5, the starting pilot discharge cell and the normal pilot discharge cell are not lit when the device is powered on (period t ₀ −t ₁ ), so the current limiting circuit 24 does not work. A high level voltage is applied to the discharge cells. During the period t ₁ - _{t 2} , when discharge starts in the starting pilot discharge cell and a discharge current begins to flow, the limiting circuit 24 operates and the second pilot Y electrode is activated as shown in FIG. 22
The applied voltage waveform drops significantly toward the lower level. Therefore, the voltage waveform applied to the starting pilot discharge cell also drops significantly. As a result, the discharge current flowing through the cell becomes a small current, which is significantly smaller than the hypothetical one shown in the figure e (therefore, the discharge is also weak). With this small discharge current, there is no risk of deteriorating the dielectric layer corresponding to the cell.

According to the lighting of the starting pilot discharge cell, the normal pilot discharge cell will also be lit instantaneously due to the pilot flame effect caused by the initial strong discharge. Note that a slight drop in level is seen in the voltage waveforms in FIGS. 5a, b, and d, but this is caused by the resistors R ₁ and R ₂ in the pilot voltage pulse generation circuit 24.

As is clear from the above description, according to the present invention, a starting pilot discharge cell is provided in the vicinity of the pilot discharge cell, and the pilot discharge cell is activated by the instantaneous (initial) strong discharge of this cell. Since the lighting is encouraged, the delay in lighting the pilot flame can be significantly shortened. Moreover, subsequent weak discharges are not noticeable and do not deteriorate display quality. Moreover,
Since a voltage pulse is applied to the starting pilot discharge cell from the pilot voltage pulse generation circuit via a simple current limiting circuit, there is no risk of deteriorating the surface of the corresponding dielectric layer. , it also has the advantage of requiring little power consumption.

Therefore, it is extremely advantageous to apply the present invention to an AC-driven gas discharge display device for matrix display.

[Brief explanation of the drawing]

Fig. 1 is a voltage waveform diagram for explaining the basic operation of a gas discharge display panel, Fig. 2 is a configuration diagram of an example of a conventional matrix type gas discharge display device, and Fig. 3 is a diagram showing the operation of the device shown in Fig. 2. FIG. 4 is a voltage waveform diagram for explaining the present invention; FIG. 4 is a diagram showing an example of the electrode structure and pilot voltage panel generation circuit of the gas discharge display panel according to the present invention; FIG. 5 is a drive diagram for explaining the effects of the present invention FIG. 1: Matrix type gas discharge display panel, 2 and 3: Maintenance voltage panel generation circuit, 4 and 5:
Write voltage generation circuit, 6 and 7: Pilot voltage pulse generation circuit, 11 and 13: Display X and Y
Electrodes, 12 and 15: X and Y electrodes for pilot flame,
22: Second pilot Y electrode, 21 and 23: Electrode piece, 24: Current limiting circuit.

Claims (1)

[Scope of Claims] 1. A plurality of X electrodes 11 and Y electrodes 13 each insulated from the discharge gas space by a dielectric layer and arranged in a direction crossing each other, and at least one of the X and Y electrode groups is provided. one electrode 12 each,
15 are connected to circuits 6 and 7 that supply voltage pulses for generating pilot discharge, and the intersection of these pilot discharge electrodes is arranged outside the gas discharge space, and the remaining portions of the X and Y electrode groups are connected to A circuit 2 that supplies each electrode with voltage pulses for maintaining discharge at a predetermined period;
3, in which the X electrode 12 or the Y electrode 15 for pilot discharge
A second pilot discharge generating electrode 22 is adjacent to the side and intersects with the Y electrode or the X electrode for pilot fire.
are provided, and these electrode intersections are configured in an enormous electrode shape, and the second pilot discharge generation electrode is connected to the voltage pulse supply circuit 7 for pilot discharge generation via a current limiting circuit 24. A gas discharge display device characterized by: