JPH04166985A - Driving method for electric discharge display panel - Google Patents

Abstract

PURPOSE:To prevent mistakes in discharge by applying to the cathode of a display cell a pulse train of the same width as a writing pulse and the same interval as maintaining pulses, and lowering the voltage between the cathode and a display anode. CONSTITUTION:During the period from the application of a scanning pulse to a cathode kj to the application of an erasing pulse, a pulse of the same width tauw as a writing pulse applied to a display anode Dj and the same period T as a maintaining pulse is superimposed on the potential Vo of the cathode kj. In order to cancel the writing pulse, the amplitude Vwe of the pulse should desirably be as near as the amplitude Vwp of the writing pulse. When the base potential of the display anode Dj is Vb(bias potential) the voltage between both of the electrodes when the writing pulse is applied with the timing different from that of the scanning pulse is Vwp + Vb - Vwe. When the amplitude Vwe is equal to the amplitude Vwp the voltage between both of the electrodes is Vb and there is no possibility of mistakes in discharge even with the maintaining pulse which is subsequently applied.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electrode driving method for a discharge display panel, and more particularly to an electrode driving method for a discharge display panel using a driving method using repetitive sustain pulses having a constant period.

(Prior Art) Discharge display panels (FDP) are expected to be used as wall-mounted televisions because they are capable of color display and are relatively easy to obtain gradations.

2. Description of the Related Art In discharge display panels used in laptop-type personal computers and the like, a line-sequential driving method is used in which one row of scanning lines is made to emit light at the same time. In this driving method, the light emission time of each display discharge cell corresponds to about one horizontal scanning period, so a relatively slow display can be realized.

However, even with this method, the brightness decreases as the number of lines on the display panel increases, so displays with low instantaneous brightness, such as color discharge display panels, cannot achieve practical level brightness for large television screens. difficult to do.

Therefore, if all display discharge cells in a panel can be made to emit light at the same time, the light emission time of each display discharge cell can be extended to the time corresponding to the maximum field, regardless of the screen size or the number of panel rows. be able to. For this purpose, it is necessary to provide the display panel with a memory function.

FIG. 2 shows an example of a schematic configuration of such a discharge display panel that has a memory function and increases luminance. In the discharge display panel of FIG. 2, the display cell DCij and the auxiliary cell ACij share the discharge electrode Ki, and each dedicates the other discharge electrode consisting of the display electrode Dj and the auxiliary electrode Aj.

Usually, the common electrode Ki operates as a cathode, and the display electrode Dj
and auxiliary electrode Aj operate as a display anode and an auxiliary anode, respectively. Display discharge cell DCij and auxiliary discharge cell AC
It is spatially connected to ij through a minute space. In this example, one display cell is arranged in one auxiliary cell, but an example in which two display cells are arranged in one auxiliary cell is also conceivable.

FIG. 3 shows an operation timing chart of the discharge display panel having the above-mentioned schematic structure. In this panel driving method, by constantly applying a sustain pulse with a constant period to the display anode, the display cell maintains a pulse discharge from the application of the write pulse to the application of the erase pulse, increasing the luminance time t and increasing the brightness. I'm raising it.

'' The two series of operations will be specifically explained with reference to FIG. A train of sustaining discharge pulses having a pulse width τs1, a repetition period T1, and a wave height Vsp is constantly applied to the display anode Dj. At this time, s, T, and Vsp are selected to be values necessary to maintain pulsed discharge, and also to values that do not cause discharge to start by themselves. Further, a constant voltage Va is continuously applied to the auxiliary anode Aj. To start discharging in the display cell Dij, a negative direction pulse (scanning pulse) with a pulse width τ and a pulse height of 1 wave Vkp is applied to the cathode Ki, and a pulse width 1W is applied to the display anode Dj.
A forward write pulse having a pulse height of 1 Vwp is applied intermittently in the discharge sustaining pulse train.

Further, in order to stop the pulse discharge of the display cell, the peak voltage of the sustaining pulse applied to the display cell is lowered. For example, as shown in FIG. 3, the cathode voltage may be changed from Vo to Ve in the positive direction.

As described above, the operating principle of a discharge display panel can be explained by the behavior of charged particles generated by discharge. That is, the reason why the discharge can be maintained by the discharge sustaining pulse is that even if the discharge stops, the charged particles generated by the discharge do not disappear immediately, but remain for a while. If the charged particles remain in this way, they become seeds and can easily emit light again.

On the other hand, since there are only a small number of such charged particles at the start of discharge, an auxiliary discharge is performed in the auxiliary cell, and the charged particles generated by the auxiliary discharge are guided to the display cell to ensure the discharge of the display cell. I'm trying to get it started.

In addition, when stopping the discharge of the display cell, an erase pulse is applied to the cathode to lower the voltage between the cathode and the display anode below the voltage required to maintain the discharge, and the charged particles disappear. Continue applying the erase pulse until

(Problems to be Solved by the Invention) As described above, in the conventional driving method, the charged particles generated in the auxiliary cell are guided to the display cell in order to start the discharge, and the charged particles = 5- Charged particles have a great influence, such as applying a sustaining pulse before the charged particles disappear, and then continuing to apply an erase pulse until the charged particles disappear to stop the discharge.

In such a discharge display panel, the display cells are arranged in a matrix, so a write pulse may be applied to display cells that are not written at a timing different from the scan pulse. Furthermore, since the sustain pulse is constantly applied, the write pulse and the sustain pulse are almost continuously applied to the display anode. Even if a sustain pulse alone cannot start a discharge, if a nearly continuous write pulse and a sustain pulse are applied, a discharge may start depending on the amount of remaining charged particles and the structure of the display cell. There were times when I ended up doing this.

As described above, differences in discharge conditions occur due to residual charged particles and variations in cell structure, making it difficult to achieve reliable display over the entire panel. Particularly in large panels, the variation tends to be large, which poses a big problem when driving.

The present invention has been made to solve this situation, and aims to provide a method for driving a discharge display panel that can prevent erroneous discharge throughout the panel.

(Means for Solving the Problems) In order to solve the problem described in item 1, the method for driving a discharge display panel of the present invention includes: - Continuously applying a sustaining pulse train sufficient to maintain the display discharge once started to the display anode; In addition, a method for driving a discharge display panel having display cells arranged in a matrix so as to display an image by respectively applying a discharge start pulse and a discharge erase pulse between a display anode and a cathode constituting electrodes of the display cells. The write pulse train is continuously applied to the cathode during most of the period in which the erase pulse is not applied.

(Function) In the driving method of the discharge display panel of the above-mentioned structure, during most of the period when no erase pulse is applied, a pulse train with the same width as the write pulse and the same interval as the sustain pulse is applied to the cathode of the display cell. By applying this voltage to reduce the voltage between the cathode and the display anode, false discharge can be prevented.

(Example) Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows the basic electrode drive waveform of the present invention. This driving waveform is the same as that shown in FIG. 3 as a conventional example, but the different feature is that during the period from applying the scanning pulse to the cathode to applying the erasing pulse, the potential Vo of the cathode changes. The purpose is to superimpose a pulse having the same width τW as the write pulse applied to the display anode and the same period T as the sustain pulse. The amplitude Vwe of this pulse may be any value, but in order to cancel the write pulse, the amplitude Vwe of the write pulse
The closer it is to w p, the more desirable it is. The base potential Vo of the cathode is set to earth potential (Ov), and the base potential of the display anode is set to vb (
bias potential), the voltage between the two poles when a write pulse is applied at a timing different from the scan pulse is Vwp+Vb-Vwe. When the amplitude V w e is equal to V w p, the voltage between the two poles becomes vb, and even when combined with the sustain pulse that is subsequently applied, there is no possibility of erroneous discharge.

In the example of FIG. 1, the display cell DCII is not discharged;
Display cells DC21 and DC31 show the case of discharge. The write pulse was applied to the display anode of the display cell DCII at a timing different from the scan pulse due to the application of the display cells DC21, DC31i, and Jt pulses. However, the amplitude Vw due to the driving method of the present invention
Due to the pulse e, the write pulse is not substantially applied between the two electrodes of the display cell, and the cause of erroneous discharge is eliminated.

In the explanation of FIG. 1, the pulse width of the amplitude V w e superimposed on the cathode is set to be the same as the write pulse width τW, but it can be set to a different size from τW as long as erroneous discharge does not occur. be.

In the above explanation, the method of sequentially accessing the cathodes has been described, but it is clear that the same effect can be obtained even when the cathodes are accessed randomly. Furthermore, when the driving speed is set to 1 (I), this driving method can be applied even when there is no auxiliary discharge.

(Effects of the Invention) As explained above, according to the driving method of the present invention, the necessary and minimum pulse is applied between the display anode and the cathode of the discharge display panel. Erroneous discharge can be prevented. In particular, in large panels, there are large variations in the display cell structure due to the manufacturing process, which causes differences in the discharge conditions of the display cells, making it easy for erroneous discharges to occur.

However, the driving method of the present invention has great effects, such as being able to overcome the difficulties in the manufacturing process of large panels.

[Brief explanation of drawings]

FIG. 1 shows an electrode drive waveform according to the present invention, FIG. 2 shows an embodiment of the configuration of a discharge panel according to the present invention, and FIG. 3 shows an electrode drive waveform according to the prior art. Aj・auxiliary anode, ACij...auxiliary cell, Dj...
Display anode, 1) Cij...display cell, Ki...cathode.

Claims (1)

[Claims] A sustain pulse train sufficient to maintain the display discharge once started is continuously applied to the display anode, and a discharge start pulse and a discharge erase pulse are respectively applied between the display anode and the cathode that constitute the electrodes of the display cell. A method for driving a discharge display panel having display cells arranged in a matrix to perform display, characterized in that a write pulse train is continuously applied to the cathode during most of the period in which the erase pulse is not applied. A method for driving a discharge display panel.