JPS6327893A - Driving of plasma display device - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for driving a plasma display, and particularly to a method for driving a plasma display (AC refresh type plasma display).
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Conventionally, as a driving method for this type of ACIJ fresh plasma display (FDP), a voltage waveform applied to either one of an insulator and an external electrode group facing each other through a discharge space is time-divisionally applied. When the voltage waveform applied to the one electrode group is turned on, a pulse voltage of the opposite phase is applied to the other electrode group, and when the voltage waveform is not turned on, a pulse voltage of the same phase is applied to the other electrode group. It is shown in Japanese Patent Publication No. 55-48318 that stable operation is achieved by applying a voltage.

In the conventional driving method described above, pulse voltages of opposite phase and the same phase are applied to each electrode of the electrode group formed on the same insulator in response to lighting and non-lighting. Electrically, the drive circuit is coupled through the stray capacitance between the respective electrodes, and the power consumption of the drive circuit is maximized when a lighting or non-lighting state occurs between adjacent electrodes. Furthermore, the brightness of the ACIJ Fresh PDP is determined by the number of pulses included in a unit time, but as the number of pulses increases, the power consumption of the drive circuit increases, so the drive frequency is limited and sufficient brightness cannot be obtained. The drawback was that it was difficult to do so.

On the other hand, if a time lag occurs between the high-frequency pulses applied to the scanning electrode group and the data electrode group, Japanese Patent Publication No. 55-483
This method exhibited a different operation from the case disclosed in No. 18, and had the drawback that the driving voltage range was narrow.

Furthermore, when a transparent electrode is used as the data side electrode, a distributed constant circuit is formed by the stray capacitance between this transparent electrode and the electrode, and the output of the drive circuit and the waveform at the tip of the transparent electrode are , and because the voltages are different, there is a drawback that uneven brightness occurs.

The present invention provides a driving method that eliminates the drawbacks of the above-mentioned conventional ACIJ fresh type plasma display phase selection driving method. That is, depending on the presence or absence of display, the waveform of the voltage applied to the row electrodes and the period during which a waveform voltage with the opposite phase or the same phase as the voltage applied to the row electrodes is applied to the column electrodes and the waveform of the voltage applied to the row electrodes, as in the conventional phase selection method. and the period during which a completely unrelated voltage is applied to the column electrodes,
- The power consumed during the period in which a voltage similar to that in the conventional phase select method is applied, which is included in the scanning period, is the same as in the conventional phase select method, but the waveform of the voltage applied to the row electrodes is The power consumed during the period when a voltage completely unrelated to the current voltage, that is, a DC voltage, is applied to the column electrodes is significantly reduced because the power consumed between the column electrodes becomes negligible.

Furthermore, by lowering the drive frequency during the period when the same drive as in the phase selection method is performed and increasing the frequency during the period when a DC voltage is applied to the row electrodes, it is possible to stabilize the drive and further reduce power consumption.

The driving method of the A CIJ 7 Letssier type plasma display of the present invention is that an electrode group is formed on a glass plate, and the electrode group connects two glass plates covered with a dielectric material, with the dielectric material facing each other and separated at an appropriate distance. between the electrodes of a plasma display panel, which has a structure in which the periphery is hermetically sealed with a glass frit and neon gas is sealed inside.
When driving by applying a pulsed voltage, when applying a pulsed voltage to only one electrode and keeping the other electrode at zero potential to cause a discharge between the electrodes, one discharge cell in the plasma display panel However, if the discharge voltage is defined as the minimum single-blade discharge starting voltage (VDm group), and the discharge voltage of all cells of the plasma display panel is defined as the maximum discharge starting voltage (VDmax), then one electrode of the plasma display , VDmin) is also high (, VDmax
If a pulsed voltage (■0) lower than that is applied and a pulsed voltage (vl) with the opposite phase and the same phase as that is applied to the other electrode, VDmin:)IVOI-IVI l f
) When the conditions are met, the discharge stops and VDmax(l v
This is an improved driving method that utilizes the fact that discharge starts when the condition o l + l Vl l is satisfied.

When a pulsed voltage higher than the maximum discharge starting voltage is applied to one electrode and a DC voltage is applied to the other electrode, all cells in the panel start discharging, but the discharge occurs only after the voltage is applied. It takes time for the discharge to start, and although it varies depending on the applied voltage, the discharge delay time in the general KACIJ fresh method is 5 microseconds or more. On the other hand, the discharge response after discharge is started is very fast, taking less than 100 nanoseconds.

The driving method of the AC refresh type plasma display of the present invention takes advantage of this discharge delay phenomenon, and applies a pulsed voltage higher than the single-blade discharge starting voltage to one electrode, and displays the display in the same way as the conventional phase selection method. Apply in-phase and anti-phase pulsed voltages to the other electrode according to the presence or absence of
Discharge cells that should be discharged are discharged, discharge cells that are not to be discharged are not discharged, and then the pulsed voltage of the other electrode is removed and the pulsed voltage applied only to one electrode is applied. This is a method of driving the FDP by sustaining the state and repeating the process of returning to the state similar to the conventional phase selection method before the non-lighted cells are lit with a pulsed voltage of one electrode.

That is, if the state driven by the conventional phase selection method is defined as the address state, and the state in which the address state is maintained by applying a pulsed voltage to one electrode is defined as the hold state, then the drive method of the present invention is defined as the address state. It is characterized by repeating the state and hold state alternately.

Next, a detailed description will be given with reference to the drawings.

FIG. 1 is a timing chart of voltage arrangement according to the first embodiment of the present invention. FIG. 2 is a timing chart for explaining the timing of the pulsed voltage that can be applied to the scanning electrodes.

The plasma display panel used in the driving method of the present invention consists of two glass plates each having electrode groups covered with a dielectric, the electrode groups facing each other, each electrode group intersecting at right angles, and the intersection point being the light emitting point for display. It is designed to be. To drive this plasma display panel, generally, a horizontal synchronizing signal shown in 2-B of FIG.
The first electrode is selected for a period of time, and a pulsed voltage having a peak value vO shown at 2-A in FIG. 2 is applied to the first electrode. In the case of a panel having m horizontal electrodes and n vertical electrodes, n vertical electrodes are selected and driven relative to the first horizontal electrode.

Next K, after a certain period (blanking period), the second
electrode is selected, and like the first electrode, vO
A pulsed voltage having a peak value of is applied to the second electrode. (Refer to Fig. 2-2-B) A pulsed voltage is applied to the third electrode after the pulsed voltage is applied to the second electrode, and this operation is repeated sequentially, and the vertical synchronizing signal is It lasts for a period (V) until it enters. The state in which the first electrode can be selected is returned by the vertical synchronizing signal shown in FIG. 2-2-L).

That is, in the scanning method of this method, the horizontal synchronizing signal is used to scan sequentially, and after all the horizontal electrodes have been scanned, the original state is restored by the input vertical synchronizing signal. The vertical synchronization signal matches the refresh frequency of the display and is generally chosen to be 60 cycles or more. On the other hand, although the number of horizontal synchronization signals included in one period of the vertical synchronization signal matches the number of scan lines, generally the number of scan lines does not match the number of scan electrodes of the panel.
The number of scanning lines is greater than the number of scanning electrodes on the panel.

1-A in FIG. 1 shows a pulsed voltage applied to the first row electrode, and 1-B and 1-C in FIG. 1 indicate the m-th column and n-th column, respectively.
It shows the pulsed voltage applied to the column electrodes.

1-C and 1-L in FIG. 1 are the discharge light emitting point (1st row, mth column) cell formed at the intersection of the 1st row electrode, the m-th column electrode, and the n-th column electrode, respectively; (row, n column) shows the voltage waveform applied to the cell.

Since the voltage waveform applied to the m-th column electrode is in opposite phase to the voltage waveform applied to the first row electrode, (1st row, m
Cells in column ) are in lighting mode.

On the other hand, since the pulsed voltage applied to the n-th column electrode is in phase with the pulsed voltage applied to the first row electrode (1st row, nth column), the cell is in a non-lighting mode, that is, a light-off mode. It is.

(1st row, m column) The pulsed voltage applied to the cell is the first
It is expressed by the potential difference between the pulsed voltages applied to the row electrode and the m-th column electrode, and has the waveform 1-D in FIG.

(Row 1, Column n) The pulsed voltage applied to the cell is similarly expressed as a potential difference as shown in FIG. 1-E.

The driving method according to the present invention is characterized in that during the H period when the row electrodes are selected, the a period in which a pulsed voltage is applied to the column electrodes depending on whether or not there is a display, and the b period in which a DC voltage is applied irrespective of the display. This method differs from conventional phase selection methods in that it determines .

The operation of period a during period H is described in patent publication No. 55-48318.
This period is defined as the address state in the present invention. On the other hand, as shown in FIG. 1-D and 1-E, the voltages applied to the lit cells and unlit cells during the b period of the H period are exactly the same regardless of whether the lights are on or off. Defined as a hold state. First, the operation in the address state is VDmax (lV11+1VO1-(1)VDmin)
l vo l-l Vl l (2)+1),
If the +21 condition is satisfied, cells that should be lit are lit, and cells that should not be lit are turned off.

In the hold mode, as shown in the voltage waveform of period (a) in Figure 1 1-D and 1-E, a pulse voltage with an amplitude of (■0) is applied regardless of whether the light is on or off. The state created by the address state applied prior to the state is maintained during this period to perform display. In other words, the cell in (1st row, m column) that is lit in the address state discharges during period (a) and is filled with charged particles generated by the discharge, so the voltage is lower than that in the address state. Discharge starts easily even in the hold state where is applied.

On the other hand, in the cell (1st row, n column) that is not lit in the address state, the applied voltage is lower than the discharge start voltage during the address state period, and there are no charged particles in the cell (1st row, n column), and the discharge is a
A certain amount of time is required to start discharging at the voltage applied during the subsequent period b without starting during the period b,
By appropriately selecting period b, it is possible to determine a voltage at which discharge does not start in the hold state.

An example will be described in which a plasma display having 640×400 dots is driven using the above-described solid driving method.

The applied voltage VO in Figure 1-A is 180V, and its frequency is 8.
00KHz, the applied voltage v1 of Figure 1 1-8, 1-C is 3
0v1 Its frequency is 800 KHz If the a period is 2 degrees microseconds and the b period is 10 microseconds, then
It showed stable operation and obtained the following results.

Conventional 7Aze selection method Invention power 40W 28W brightness
10fL 9.4fL FIG. 3 shows the arrangement of pulse voltages in the second embodiment.

FIG. 3-3A shows the pulsed voltage applied to the N row electrodes of the plasma display.

3-B shows the pulsed voltage applied to the m-column electrode, and FIG. 3-3-C shows the pulsed voltage applied to the n-column electrode.

FIG. 3-3-D shows a pulsed voltage applied to a cell (N row, m column) formed at the intersection of the N row electrode and the m column electrode,
FIG. 3-3E shows a pulsed voltage applied to a cell (N row, n column) formed at the intersection of the N row electrode and the n column electrode.

In FIG. 3, the period indicated by C indicates the blanking time, and the period indicated by a is the time during which display is performed in the address state. The period indicated by b is the time during which display is performed in the hold state. Further, the period a+b+c is one scanning time.

A case will be described in which a plasma display having 640×400 display points is driven with a pulsed voltage shown in FIG.

The voltage shown in Fig. 3-A is 170V, the frequency in the address state is 500KH2, the frequency in the hold state is 2 MHz, and the voltage shown in Fig. 3-B and 3-C is 30v1 in the address state. Stable operation was obtained by driving at a frequency of 500 KHz and a DC frequency in the hold state.

When compared with the conventional phase selection method, the power consumption and brightness obtained by this driving method were equal to the following mD.

Power consumption Brightness phase selection method 40W 10fL book
Invention 15W 12fL Power consumption and brightness also vary depending on the ratio of the address state time a to the hold state time s in FIG.

The above data is for a case where the ratio of address state time to hold time is 1:2.

As explained above, the present invention provides a period during one scanning period in which no high-frequency voltage is applied to the data side electrodes, and has the effect of reducing the power consumed between the data side electrodes during this period. This has the effect of increasing the frequency of the pulse voltage applied to the side electrodes, increasing the number of discharges during one scanning period, and increasing the brightness.

Furthermore, in panels where a NESA electrode is used as the data side electrode, by lowering the frequency of the address period below the time constant formed by the stray between the NESA electrode and the electrode, the entire panel can have a waveform that is almost the same as the output waveform of the circuit. It also has the effect of making the movement more stable.

[Brief explanation of the drawing]

FIG. 1 shows applied voltage waveforms in an embodiment of the present invention. 1-A shows the pulse voltage applied to the scanning electrode of the first row, FIG. 1-B shows the data-side electrode of the m-th column, and FIG. 1-C shows the pulse voltage applied to the data-side electrode of the n-th column. Each of the pulsed voltage waveforms to be applied is shown. 1-D and 1-E in FIG. 1 respectively show the state of the voltage applied to the cells (row 1, column m) and (row 1, column n). FIG. 2 shows the pulsed voltage applied to the scanning electrodes. FIG. 3 shows the pulsed voltage applied to the electrodes in the first row and column of the second embodiment. Agent: Susumu Uchihara, patent attorney. $l Figure 2 M To÷

Claims (1)

[Claims] Voltages are sequentially applied in a time-division manner to a group of scanning electrodes of a plasma display panel whose electrodes are covered with a dielectric material, and the scanning is performed in synchronization with the voltage applied to each scanning electrode. In a plasma display refresh drive method in which a voltage is applied to the data-side electrode group according to the presence or absence of data to drive the plasma display, display is performed in an address state during one scanning period and display is performed in a hold state. 1. A method for driving a plasma display, comprising: a pulse voltage applied to a scan electrode in a hold state; the frequency is higher than the frequency in an address state; Note that the address state and hold state referred to here are defined as follows. That is, in synchronization with the pulsed voltage applied to the scan electrode during one scan period when one scan electrode is selected, and in addition, the data side electrode corresponding to the cell to be displayed has an opposite phase, and the cell that should not be displayed is synchronized with the pulse voltage applied to the scan electrode. The state during which a pulsed voltage of the same phase is applied to the data-side electrode corresponding to the display is called the address state, and the pulsed voltage that had been applied to the data-side electrode is stopped, and the charge created in the address state is called the address state. A state during a period in which the particles are driven only by pulsed voltages applied to the scanning electrodes is defined as a hold state.