JPH02230185A - Control of plasma display panel for each dot - Google Patents

Abstract

PURPOSE: To attain the control of each point in a plasma display panel regulating each pixel by a control electrode and a pair of maintain(MT) electrodes by regulating the polarity and timing of voltage to be impressed to these electrodes. CONSTITUTION: A display pixel consists of a control electrode Xj and a pair of MT electrodes (Yae)i, (Ye) and indicates 1st MT voltage V(Yae), 2nd MT voltage V(Ye) and an optical pulse 30 indicating a difference between both the voltage values and appearing on each end part. Voltage is changed at a cycle of a period T, and when a recording pulse is impressed to the electrode Xj on a part Ti where the polarity signs of both the voltage are reversed, their voltage difference is also added, voltage is suddenly boosted and gas discharge is maintained. On a part Te where the polarity signs are the same, an impressed pulse removes and erases charge existing in the MT electrodes. Since suitable voltage is impressed to all the MT electrodes, the screen can be completely erased or erased in each line.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for point-sequential control of a plasma display panel. The present invention is applicable to displaying analog, alphanumeric, or other images, for example in color.

2. Description of the Related Art Plasma display panels currently occupy an important position as flat panel display devices. Devices are known that include two insulating plates defining a volume in which a gas (generally a neon-based gas mixture) is accommodated. These plates support two intersecting groups of electrodes that define the pixel matrix. Proper excitation of the electrodes causes a discharge in the gas, which emits light.

Preferably, the improved plasma display panel includes means for maintaining this discharge. According to an embodiment that appears to be advantageous, this means consists of so-called sustain electrodes deposited in pairs on the same substrate. Therefore,
This plasma display panel is called a coplanar complete maintenance plasma display panel.

A device of this type is shown in FIGS. 1 and 2. This device is described in European Patent Application No. 135. 382
listed in the number. The device comprises a glass plate 1 with sustain electrodes 2 and 3 coated on its surface. Each sustain electrode 2, 3 is provided with a protrusion 2a, 3a. This unit is covered with an insulating layer 4. The write electrode 5 crosses the sustain electrodes 2 and 3. This unit is covered with an insulating layer 6 and a protective layer 7 made of MgO.

A second plate 8 completes this unit. Gas 9 is contained between two plates kept separated by airtight shims (not shown).

The operating principle of this type of plasma display panel is as follows. In other words, the addressing discharge is applied to the electrode 5.
selectively generated at the intersection of electrode 2 and electrode 2. This discharge causes charge to accumulate in the insulating material covering the electrode. This discharge is then utilized to facilitate the generation of a sustaining discharge between electrodes 2 and 3 which are parallel and coplanar with each other. This discharge, which provides most of the useful light, is maintained by applying a voltage between electrodes 2 and 3 in one direction and then in the other direction.

The value of this type of structure, with three electrodes per pixel, is twofold.

First, a sustaining discharge occurs outside the intersection 2-5. Effective light is not blocked by the electrodes and therefore the gain in light output is high.

Second, the sustaining discharge is localized to a single substrate (the level supporting electrodes 2, 3, 5). Therefore, another substrate can be used, for example, to deposit the phosphor, which will be protected from discharge.

The method of controlling this type of plasma display panel is a line-by-line control method as described in the above-mentioned document. This means that all points located under the same electrode 5 are controlled. Using this method, it is not possible to control the plasma display panel point by point. Point-by-point control methods are useful for displaying video images. This is because this method is consistent with the structure of the video image signal.

G. Double 21. Dick (G, W, nick)
rsID Proceedings” Volume 27/3, 19
1986, pages 183 to 187, describes a plasma display panel that uses a coplanar maintenance method and has three electrodes per pixel. The control principle of this type of plasma display panel is shown in FIG.

In this drawing, the sustain electrodes are designated Y1 and E (electrode E has no identifying subscript ] since all sustain electrodes of this type have the same voltage applied to them). . Address electrodes are indicated by an X. Therefore, pixel PI, is defined by two indices 1 and j. The sustain signal consists of a first alternating current voltage that is applied to all the electrodes E and is alternately positive and negative, and a second voltage that is applied to all the electrodes Yl and whose phase is opposite to the first voltage. Therefore, when the electrode E is at +V, the electrode Y1 is at the potential V, conversely.

The method of addressing the pixel PIJ, ie turning it on (ie starting to fire) or turning it off (extinguishing), consists of two steps.

a) First, insert one step in the sustain signal and connect the electrode YI to ground (reference level) in this step. Next, a positive pulse (amplitude +V
b) is applied. If the final result is to fire the pixel, simultaneously apply a negative pulse -Vy to the corresponding electrode Y1
to be applied.

b) Immediately after this first step, a pulse of amplitude +Ve is applied to electrode E. In this way, discharge can be caused only at a selected point between X and E, that is, at a point where discharge occurs between X and Y. As a result, the ignition state of the corresponding point is finally maintained, i.e., a series of discharges between near the intersection of Yi-X and YI.

No pulse -Vy is applied to the unselected electrodes Y, leaving that point in its previous state (on or off).

This addressing method is used to selectively control each pixel point by point. This method is also compatible with semi-selective control (row-by-row or column-by-column control) methods.

The disadvantage of this method is that complex signals are required. Four different voltage levels appear on electrode Y8 and three different voltage levels appear on electrode E. Additionally, this method results in extremely long address sequences, which limits the maximum speed at which information can be updated on the screen.

Another type of plasma display panel to which the method of the invention can be successfully applied is shown in FIG. This type of plasma display panel itself is based on the French Patent Application No. 88 03953 filed by the present applicant and the patent application filed on the same day as the present application (claiming first priority right). 1). Therefore, this type of plasma display panel is not known and is described here for the sake of a thorough explanation.

The plasma display panel of FIG. 4 includes a first glass plate 10 whose surface is coated with a first group of electrodes XJ (J is an integer from 1 to N).
Only one electrode, X, is shown). plate 10
and electrodes X, is covered with a layer of dielectric material 12. This dielectric material layer 12 may be covered with an oxide layer (not shown) such as MgO to make electron emission easier. On this layer of dielectric material l2 there are spots 14 of luminescent material, ie a material capable of developing a color upon irradiation with ultraviolet light.

The plasma display panel also includes a second glass plate 20 coated with a second group of counter electrodes. The counter electrodes are called an address-sustain electrode (Ye.) (1 is an integer from 1 to P) and a sustain electrode (Y@), respectively. The address-sustain electrode and the sustain electrode are provided with protrusions 22 and 24 at positions facing each other. This unit with plate 20 and these electrodes is covered with a layer of dielectric material 26.

During normal operation, the two plates 10, 20 and the electrode arrays on their surfaces are brought into close proximity and separated by the thickness of a shim (not shown). Gas is contained in the space between the plate and the shim.

Thus, once assembled, the plasma display panel will have two orthogonal electrode arrays. That is, electrode X, is perpendicular to electrode (Ye.)i, (Ye). Electrode X, may overlap projections 22 and 24 or may be slightly offset laterally.

In this way, pixel P1 is defined by electrode X and a pair of sustain electrodes (Ye.)i, (Ye).

Problem to be Solved by the Invention When this type of plasma display panel is controlled by the above-mentioned known method, the same problems arise again. That is, the control is complex, and it is a semi-selective addressing method, that is, a row-by-row or column-by-column addressing method, rather than a point-by-point addressing method.

It is an object of the present invention to overcome the above-mentioned problems by providing a simple point-by-point control method that can be used in particular (but not exclusively) for plasma display panels of the type shown in FIG. It's about solving it.

More specifically, according to the invention, the following procedure is utilized.

a) Apply a set of cyclic sustain voltages to maintain the display, this set being applied to all first address-sustain electrodes (Ye.) and consisting of a number of cycles (T). and each cycle includes a first portion formed by a pulse of a first polarity followed by a pulse of a second polarity;
a first voltage V (Ye.) with a peak-to-peak amplitude equal to the value Vy; and is formed by a cycle (T) of the same duration as the cycle of the first voltage, and each cycle is formed by the first voltage V (Ye.) applied to the first sustain electrode. a second voltage V comprising a first portion formed by pulses of opposite polarity and a second portion formed by a pulse of said second polarity followed by a pulse of said first polarity; (Ye), the peak-to-peak amplitude of said second voltage for sustaining is equal to the value V6, and said first part of the cycle of this second voltage includes a first period called a recording period. A period ('r+) exists, during which a first voltage V (Ye.) is applied to the address-sustain electrode and a second voltage V (Ye) is applied to the sustain electrode. have a first polarity and a second polarity, respectively, and there is a second period called an erase period in the second part of the cycle, during which the voltage is applied to the address sustain electrode. The first voltage V (
Ye. ) and a second voltage V(Y
e) are of the same second polarity, and b) for control, an addressing pulse with the first polarity and amplitude VX is applied to the pixels P. applied to the control electrodes (X1) of said first group during the recording period (T, ) to fire the pixels or during the erase period (T.) to extinguish the pixels; - The first voltage V (Ye.) i applied to the sustain electrode (Ye.) does not change if it turns on or off the state of the pixel Pij, respectively, and does not change the state of the pixel PI, If it is desired to maintain the voltage at the same time and keep it on when it is ignited, and keep it off when it is extinguished, the voltage is applied to the first address-sustain electrode (Ye.). First voltage V (Ye.)
The same voltage as the address pulse or a voltage of the same polarity is applied to i.

Therefore, according to the present invention, there are three voltages VN, VySV
Only e is primarily used. As a result, the amplitude vy is determined as a function of the amplitude VX such that the voltage VX+vy is sufficient to start lighting up the plasma between the control electrode (X) and the address-sustain electrode (Yes}
is determined as a function of Vy thus determined, so that the voltage Vy+Vy is the address-sustain electrode (yas)
The value is set to be sufficient to maintain the plasma light between i and the adjacent sustain electrode (Ye).

It can be seen that voltages Vy and V0 do not necessarily have to have the same amplitude, unlike in the conventional case (see FIG. 3).

Addressing voltages of any shape can be used, but
In practice it is preferable to use a square wave voltage.

Furthermore, at the moment of transition, electrode Y. ．． It is always possible to apply an intermediate voltage level to i, Y6 to reduce the capacitive voltage.

In any case, the features of the invention will become clearer from the following description of an exemplary embodiment with reference to the accompanying drawings.

Example Several signals and voltages are shown in FIG.

a indicates the first sustain voltage v (y..) applied to the address-sustain electrode Yao.

b is the second sustain voltage V (Y
e) is shown.

C is the difference between these two sustaining voltages (V (Ye.) - V
(Ye)).

d indicates the light pulse appearing at each end of the voltage difference (V (Ya.) - V (Ye)). These light pulses represent the sustaining of the discharge, and in the illustrated embodiment are assumed to have been lit since before the illustrated cycle.

It can be seen that the illustrated voltage has the characteristic of changing in cycles of period T. Periods TI and T. are for recording and erasing, respectively, and the voltages V (Ye.) and V (Ye)
have opposite or the same polarity.

FIG. 6 is a diagram showing the recording stage. During the period T1, a recording pulse I, is applied to the electrode X', but another voltage (b
) will not change. This results in a voltage difference (V
(X.+) V (Ye-) i) (c) suddenly becomes thick (V (XJ) V (Ye-)
Gas (d) discharges 32 in response to the leading edge of the excess voltage of i). This discharge causes an electric charge to appear on the electrode.

The charge is opposed by the discharge being maintained. However, this charge is utilized to sustain the discharge (pulse 30) shown in Figure 5d.

The two stage ignition mechanism is better understood by looking at FIG. First, the electrode (X,) and the address-sustain electrode (y
aa) Record by discharging between 1 (a) and then restoring the charge (b) by discharging alternately between sustain electrodes (Ye@) i and (Y0).

The sign of the charge is indicated symbolically in FIG. 6b.

When applying a recording pulse V(XJ) to the corresponding electrode XJ but not changing the state of the pixel Pij, FIG. 6b
As shown by the dotted line, the recording pulse is changed to the voltage v (Ya-)
All you have to do is superimpose it on top of 1. The pixel Pij then remains on when it is in the on state, and remains off when it is in the off state.

FIG. 8 shows the voltages applied during the erase phase. During the period T8, the erase pulse I. (a) is applied.

The other voltages V (Ye.) i and V (Ye) do not change (b and C). The sustain discharge 30 in FIG. 8d disappears when the erase pulse is applied because the charges existing in the address-sustain electrode (Ye.)l are removed.

FIG. 9 shows the charge during the sustain phase (a) and immediately after the erase pulse (b). Charges are indicated by symbols as in FIG.

If it is not desired to erase the pixel PIJ, the same pulse applied to the electrode XJ is superimposed on the voltage y (Ye.) l. This voltage is shown as a dotted line in FIG. 8b.

Therefore, in any case, the same pulse applied to the electrode Xj for recording or erasing at the address stage is applied to the voltage
By superimposing it on J (Yaa) l, the status quo is maintained.

In another embodiment of this method, the voltage y (yas) 1 applied to the address-sustain electrodes is applied to the erase period T. Between +Vy and -Vy, an intermediate level can be taken.

It can be seen that by applying appropriate voltages to all sustain electrodes it is possible to erase the screen completely, or one row or column at a time.

Although the method of the invention is essentially a selective addressing of pixels, it is also suitable for semi-selective addressing of entire rows or entire columns.

Additionally, the simpler signals simplify the control of electronic systems. Only three voltage levels are applied to electrode Ya. It is necessary to apply two voltage levels to the electrode Y8. Since the pulses for the six addresses can be the same, only one pulse generator is required. However, it is of course possible not to use the same addressing voltages if necessary.

Furthermore, the addressing time can be shortened since special steps are no longer required as in the past. This results in faster access.

Finally, electrode X. Since fewer discharges are involved, the light emitter is degraded to a lesser extent (ie, has a longer lifetime).

Finally, FIG. 10 is a schematic diagram of the plasma panel display of the present invention and its control means. In the plasma panel display 40, the control electrodes X, ( ] is an integer from 1 to N) are connected to an address circuit 42 with N outputs,
The sustain electrode (Ye. i or an integer from 1 to P) is P
It is connected to the address circuit 44 of the output, and the electrode (Y8) is connected to the generator 46. Information to be displayed is input from human input 48 to decoder 50 . This decoder 50 outputs a decode signal SDI to the address circuit 42 and a decode signal SDY to the address circuit 44.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional plasma panel display. FIG. 2 is a plan view of this same plasma panel display. FIG. 3 is a diagram showing a conventional control method. FIG. 4 is a diagram of a new type of plasma panel display to which the present invention can be applied. FIG. 5 shows the shape of the sustaining voltage of the method of the invention, and the sustaining mechanism is explained in this figure. FIG. 6 shows the recording signal and explains the mechanism by which the pixels are turned on. FIGS. 7a and 7b are schematic diagrams of the shape of the discharge generated between the electrodes during the recording stage. FIG. 8 shows the erase signal and explains the erase mechanism. Figures 9a and b are schematic illustrations of the charge present on the electrodes during the erase phase. FIG. 10 is a schematic diagram of a plasma panel display and its control means. (Main reference numbers) 1, 8, 10, 20...Glass plate, 2, 3, E,
Y. , Yl, ... sustain electrode, 2a, 3a, 22,
24... Protrusion, 4, 6... Insulating layer, 5... Writing electrode, 7...
Protective layer, 9... Gas, 12, 26... Dielectric material layer, 14... Luminescent material dot, 40... Plasma display panel 42, 44... Address circuit, 50... Decoder, PI,... Pixel, X,...
Address electrode (control electrode), (Ye.) i...address-sustain electrode

Claims (3)

[Claims] (1) A first group of control electrodes and a counter electrode called a sustain electrode, one electrode of the pair is called an address-sustain electrode and the other electrode is a second group of electrodes called a sustain electrode. , the sustain electrodes are parallel to each other and the first
The sustain electrodes each have a protrusion, and the protrusion of one electrode faces the protrusion of the same pair of electrodes.
j is a method for point-by-point control of a plasma display panel substantially defined by an overlap area between a control electrode and a pair of sustain electrode protrusions, comprising: a) a set of cyclic sustain voltages; applied to all sustain electrodes, this set consists of a plurality of cycles T, each cycle consisting of a pulse of the first polarity followed by a pulse of the first polarity; a first portion formed by a pulse of two polarities followed by a pulse of said second polarity, and a second portion formed by a pulse of said first polarity followed by a pulse of said second polarity; The first whose amplitude is equal to the value V_y
voltage V(Y_a_e) of - applied to all sustain electrodes and formed by cycles T of the same duration as the cycles of said first voltage, each cycle being applied to said first sustain electrode; a first portion formed by a pulse of opposite polarity to the first voltage V(Y_a_e), and a pulse of the second polarity followed by a pulse of the first polarity. a second voltage V(Y_e) comprising a second part, the peak-to-peak amplitude of said second voltage for sustaining being equal to the value V_e, and said second voltage of said second voltage cycle for sustaining; There is a first period called a recording period in part 1, and during this recording period, the first voltage V (Y_a_e) applied to the address-sustain electrode and the first voltage V (Y_a_e) applied to the sustain electrode are 2
The voltages V(Y_e) are of a first polarity and a second polarity, respectively, and there is a second period called an erase period in the second part of the cycle, and during this erase period the address The first voltage V (Y_a_
e) and the second voltage V(Y_e
) are of the same second polarity, and b) an addressing pulse with the first polarity and amplitude V_N is applied during the recording period to fire the pixel P_i_j or during the erasing period to extinguish the pixel. A first voltage V(Y_a_e)i applied to the control electrodes of said first group and applied to said first address-sustain electrodes is adapted to cause the state of the pixel P_i_j to be ignited or extinguished, respectively. - If you wish to maintain the state of the pixel P_i_j without changing it so that it remains lit when it is lit, and remains extinguished when it is extinguished, the first c) applying the same voltage or voltage of the same polarity as the addressing pulse to the first voltage V(Y_a_e)i applied to the address-sustain electrode of the address-sustain electrode; c) determining the amplitude V_y as a function of the amplitude V_N; The voltage V_N+V_y is sufficient to start lighting up the plasma between the control electrode and the address-sustain electrode, and the amplitude V_
e is determined as a function of V_y thus determined such that the voltage V_y+V_e is of a value sufficient to maintain the plasma light between the address-sustain electrode and the adjacent sustain electrode. how to. 2. The method of claim 1, wherein the addressing pulse applied to the control electrode and optionally to the addressing sustain electrode is a square wave pulse. 3. The method of claim 1, further comprising applying an intermediate voltage level to the applied voltage at the moment of the transition.