EP0357485B1 - Method for the line-per-line control of an alternating-type plasma panel with a coplanar support - Google Patents
Method for the line-per-line control of an alternating-type plasma panel with a coplanar support Download PDFInfo
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- EP0357485B1 EP0357485B1 EP89402281A EP89402281A EP0357485B1 EP 0357485 B1 EP0357485 B1 EP 0357485B1 EP 89402281 A EP89402281 A EP 89402281A EP 89402281 A EP89402281 A EP 89402281A EP 0357485 B1 EP0357485 B1 EP 0357485B1
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- maintenance
- addressing
- gating signal
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/28—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels
- G09G3/288—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels
- G09G3/291—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels controlling the gas discharge to control a cell condition, e.g. by means of specific pulse shapes
- G09G3/294—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels controlling the gas discharge to control a cell condition, e.g. by means of specific pulse shapes for lighting or sustain discharge
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/28—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels
- G09G3/288—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels
- G09G3/291—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels controlling the gas discharge to control a cell condition, e.g. by means of specific pulse shapes
- G09G3/292—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels controlling the gas discharge to control a cell condition, e.g. by means of specific pulse shapes for reset discharge, priming discharge or erase discharge occurring in a phase other than addressing
- G09G3/2927—Details of initialising
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/28—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels
- G09G3/288—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels
- G09G3/291—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels controlling the gas discharge to control a cell condition, e.g. by means of specific pulse shapes
- G09G3/293—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels controlling the gas discharge to control a cell condition, e.g. by means of specific pulse shapes for address discharge
- G09G3/2932—Addressed by writing selected cells that are in an OFF state
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
- G09G3/28—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels
- G09G3/288—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels
- G09G3/298—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using luminous gas-discharge panels, e.g. plasma panels using AC panels using surface discharge panels
Definitions
- the present invention relates to a method of line-by-line control of a plasma panel of the alternative type with coplanar maintenance, and particularly of a plasma panel in which each elementary image point is defined substantially at the intersection of a first electrode. called “column electrode” with two other parallel electrodes called “maintenance electrodes”.
- Plasma panels are flat screen display devices, which allow the display of alphanumeric, graphic or other images, in color or not. These panels work on the principle of an emission of light produced by an electric discharge in a gas.
- Plasma panels include two insulating tiles limiting a volume occupied by a gas (generally a mixture based on neon). These slabs support crossed conductive electrodes so as to define a matrix of elementary points of images or pixels. An electric discharge in the gas, causing an emission of light at the level of an image point or pixel, takes place when the electrodes of this pixel are suitably excited.
- a gas generally a mixture based on neon.
- the aforementioned patent application also explains how to erase one or more cells, using an erasure signal, the rising edge of which is constituted by a ramp.
- each pixel of the matrix is constituted by three electrodes, more precisely at the intersection between an addressing electrode called column electrode with two parallel maintenance electrodes forming a pair of electrodes d 'interview.
- the maintenance of the discharges is ensured between the two electrodes of the same pair, and the addressing is done by generation of discharge between two crossed electrodes; by addressing is meant discharges generated so selective and / or semi-selective with a view to carrying out a registration or deletion operation.
- the maintenance electrodes comprise two families: the electrodes of a first family are called “addressing-maintenance electrodes" and the electrodes of the second family “electrodes only of maintenance".
- the maintenance addressing electrodes have the function, in cooperation with the maintenance only electrodes (of the second family), of ensuring maintenance discharges; but they also have to provide an addressing function, and therefore they must be individualized, that is to say that they must, for example, be connected to one or more pulse generating devices by the intermediary of means which make it possible to apply one or more particular pulses, to only one or more address-maintenance electrodes which are selected from the plurality of address-maintenance electrodes.
- the column electrodes are also individualized.
- these are generally connected to one or more pulse generators in such a way that these maintenance electrodes of the second family are all, at the same times, brought to the same potentials so that it is not necessary to individualize them and that they can possibly be linked together.
- a pixel is defined at the intersection of a column electrode with a pair of maintenance electrodes
- the addressing-maintenance and only maintenance electrodes may each include, at the level of each pixel, a protrusion or protruding surface; in the same pair of maintenance electrodes, the projecting surfaces of one electrode are oriented towards those of the other electrode, the maintenance discharges taking place between these projecting surfaces.
- Such a plasma screen is known in particular from the European patent document EP-A-0 135 382 which also describes a method for controlling this screen; it should be noted that in the device described in this European patent, the column electrode crosses the pairs of maintenance electrodes on the side of the projecting surfaces where the maintenance discharges are produced.
- each pixel is defined at the intersection of a column electrode with a pair of maintenance electrodes and a suitable control method are described in the article by GW DICK published in PROCEEDINGS OF THE SID , flight. 27/3, 1986, pages 183-187.
- the maintenance electrodes have a constant width, that is to say that they do not have a projecting surface facing one another in a pair of maintenance electrode, to define the maintenance discharge zone, this structure on the other hand comprises barriers made of insulating material, which serve to confine maintenance discharges in the crossing zone with the column electrode.
- FIG. 1 Another type of plasma panel, to which the method of the invention applies in a particularly advantageous manner, is represented in FIG. 1.
- a panel is the subject in itself of a French patent application No. 88 03953 filed March 25, 1988 on behalf of THOMSON-CSF.
- This French patent application was published under the number FR-A-2 629 265, the new type of plasma panel to which it relates is described below.
- the panel shown in FIG. 1 comprises a first glass slab 10 covered with a first family of electrodes denoted Xj, where j is an integer ranging from 1 to N (a single electrode Xj is shown; the slab assembly 10- electrode Xj is covered with a layer 12 of dielectric material, possibly covered with an oxide layer such as MgO (not shown) facilitating electronic emission.
- a wafer 14 of a phosphor material that is to say capable of emitting colored radiation, under the effect of ultraviolet radiation.
- the panel also comprises a second glass slab 20 covered with a second family of electrodes constituted by pairs of electrodes called respectively, of maintenance-addressing (Yae) i and of maintenance (Ye), where i is an integer between 1 and P.
- the maintenance-addressing and maintenance electrodes include protrusions or protruding surfaces 22 and 24, arranged opposite one another.
- the 20-electrode slab assembly is covered with a dielectric layer 26.
- the two slabs 10 and 20 and their networks of electrodes are brought closer together and kept apart by a thickness spacer (not shown), and a gas is present in the volume comprised between the slabs and the spacer.
- the panel thus has two arrays of orthogonal electrodes, in the sense that the electrodes Xj are orthogonal to the electrodes (Yae) i and (Ye).
- the electrodes Xj can overlap the protrusions 22 and 24 or be slightly offset on the side thereof.
- a pixel Pij is then defined by an electrode Xj (column electrode) and a pair of maintenance electrodes (Yae) i and (Ye).
- the control method according to the invention makes it possible to eliminate or considerably reduce the drawbacks mentioned above.
- the proposed control method is of the video compatible type, that is to say which allows addressing by complete line so as to reduce the scanning time; on the other hand, it allows a reduced cycle time which results in a high maintenance frequency and a high luminance.
- the proposed control method also makes it possible to reduce the number of voltage levels applied to the different electrodes and thus to simplify the control electronics; it should be noted that the method of the invention also makes it possible to apply to the column electrode only relatively low power and amplitude pulses which allows the use of integrated circuits of low cost technology .
- a method of line-by-line control of a plasma panel of the alternative type with coplanar maintenance comprising crossed column electrodes with two families of parallel maintenance electrodes, the first family of electrodes being made up of addressing-maintenance electrodes and the second family consisting of maintenance-only electrodes, each addressing-maintenance electrode forming with a maintenance-only electrode adjoining a pair of maintenance electrodes, each pair of electrodes maintenance corresponding to a line of pixels perpendicular to the column electrodes, the pixels being formed substantially at each crossing of a column electrode with a pair of maintenance electrodes, said method consisting in applying a first set of cyclic pulses to all the addressing-maintenance electrodes and a second set of cyclic pulses to all the so-called maintenance-only electrodes, the two sets of pulses having the same period, during which said implusions develop between the two electrodes of each pair of '' voltage maintenance electrodes which constitute an erasure phase and a registration phase occurring after the phase erase, said
- FIG. 2 is a general block diagram of a plasma panel 1 to which the method of applying command of the invention.
- the plasma panel 1 is mainly represented by conductors or electrodes arranged in column X1, X2, X3, X4, and by two families of maintenance conductors or electrodes arranged in line, on the one hand Y1, Y2, Y3, Y4 for the first family, and on the other hand , E1, E2, E3, E4 for the second family.
- the maintenance electrodes Y1 to Y4 and E1 to E4 are arranged in pairs, that is to say that a first electrode Y1 of the first family is associated with an adjacent electrode E1 belonging to the second family, to constitute a pair P1 of maintenance electrodes; a second electrode Y2 of the first family is associated with a second electrode E2 of the second family to constitute a second pair P2 of maintenance electrodes; and likewise for the electrodes Y3 and E3 then Y4 and E4 which respectively constitute a third and a fourth pair P3, P4 of maintenance electrodes.
- an elementary image point or pixel PX1 to PX16 is formed which is symbolized in FIG.
- each pixel which can be formed for example according to the structure represented in FIG. 1 and the two electrodes of each pair of electrodes P1 to P4 may or may not have protuberances or projecting parts (not shown in FIG. 2) shown in FIG. 1 with the marks 22, 24.
- the electrodes Y1 to Y4 of the first family are address-maintenance type electrodes, so these address-maintenance electrodes Y1 to Y4 are individualized, that is to say that they are each connected to a different output SY1 to SY4 of a first addressing device G1; the first addressing device G1 is of a conventional type in itself capable of supplying voltage pulses which will be further explained with reference to FIG. 3a.
- the electrodes E1 to E4 of the second family E are of the maintenance only type: in the non-limiting example described, they are connected together and connected to the output SE of a pulse generator device G2 which delivers voltage pulses which will be explained more clearly with reference to FIG. 3b.
- Column electrodes X1 to X4 conventionally perform only an addressing role. They are each connected to a different output SX1 to SX4 of a second addressing device G3; the second addressing device G3 delivers voltage pulses which will also be explained in a continuation of the description relating to Figures 3d to 3g.
- the devices G1, G2, G3 are themselves controlled and synchronized, in a conventional manner, by a central control unit (not shown) which manages in a known manner itself the switching on or off or the maintenance pixels PX1 to PX16 on or off.
- a line L1 to L4 is a line of pixels formed by the pixels PX1 to PX16 defined by each pair P1 to P4 of maintenance electrodes: thus the first line L1 contains the 4 pixels PX1 to PX4, and corresponds to the pair P1 of maintenance electrodes; the second line L2 contains 4 pixels PX5 to PX8 and corresponds to the second pair P2 of electrodes; the third line L3 contains the pixels PX9 to PX12 and corresponds to the third pair P3 of electrodes; the fourth line L4 contains the pixels PX13 to PX16 and corresponds to the fourth pair P4.
- FIGS. 3a to 3h show diagrams of signals explaining the operation of the plasma panel 1 controlled according to the method of the invention.
- the signals which are applied when we want to successively turn off one pixel and turn on another thus for example, on the second line L2, turn off (this is i.e. erase) the sixth PX6 pixel, and turn on (i.e.) write the seventh PX7 pixel.
- the sixth pixel PX6 is located at the intersection between the second pair of PE2 electrodes and the second column electrode X2; and that the seventh pixel PX7 is located at the intersection between the second pair of electrodes PE2 and the third column electrode X3.
- FIGS. 3a and 3b respectively show a first and a second set of cyclic voltages VY, VE which are applied respectively simultaneously to all the addressing-maintenance electrodes Y1 to Y4 and simultaneously to all the maintenance-only electrodes E1 to E4.
- FIG. 3c illustrates maintenance discharges produced between the electrodes Y2 and E2 of the second pair P2 of electrodes.
- Figures 3d, 3e, 3f, 3g respectively show voltage pulses forming masking pulses applied to the column electrodes X1 to X4.
- FIG. 3 h illustrates a DI registration discharge between the third column electrode X3 and the second electrode Y2.
- the first and second sets of voltages VY, VE vary on either side of the same reference voltage VR which is at zero volts for example.
- the first and second sets of voltage VY, VE are constituted respectively by a first and a second set of voltage pulses having a cyclic character and a same period T.
- T the combination of the applied voltage pulses of on the one hand to the address-maintenance electrodes Y1 to Y4, and, on the other hand, to the electrodes only maintenance E1 to E4, develops between the 2 electrodes of each pair P1 to P4 voltages (not shown) which determine an erasing phase T1 and a writing phase T2.
- the cycles T also include a maintenance phase T3 which is optional, as is explained further in the description below.
- a maintenance window CEe begins which is applied to the maintenance only electrodes E1 to E4, and the transition of which represents a voltage variation ⁇ VE which in example s 'performs substantially symmetrically with respect to the reference voltage VR; this first maintenance interval CEe applied to the maintenance only electrodes E1 to E4 passing for example to a negative polarity, from a voltage + VE1 to a voltage -VE1.
- this CEY maintenance slot having a positive polarity, that is to say opposite to that which at the same time is applied to the electrodes only of maintenance E1 to E4, the transition having been carried out at time t0 from a negative voltage -VY1 to a positive voltage + VY1; in the nonlimiting example described, this transition represents a voltage variation ⁇ VY1 which is carried out in a manner substantially symmetrical with respect to the reference voltage VR.
- the maintenance slots CEY and CEe applied respectively to all the addressing-maintenance electrodes Y1 to Y4 and all the maintenance electrodes E1 to E4 are maintained until an instant t2.
- the polarities of the voltages VY and VE are reversed and remain opposite until an instant t4 which marks the start of the erasure phase T1.
- the transition of the maintenance slots CEY and CEe causes a new maintenance discharge De2 at the level of the sixth pixel PX6; as for the previous maintenance discharge, this discharge ends at an instant t3 where charges accumulated on the maintenance electrodes YE, E2, with a polarity opposite to that which they had at the instant t2, are in quantity sufficient to cause extinction.
- the polarities of the voltages VE and VY applied respectively to the maintenance electrodes E1 to E4 and to the address-maintenance electrodes Y1 to Y4 reverse again and remain opposite .
- the slots applied to the electrodes only for maintenance E1 to E4 always have the same amplitude ⁇ VE, that is to say that only 2 voltage levels (+ VE1 and -VE1) are necessary to control these electrodes d interview E1 to E4.
- the voltage VE is formed by a voltage slot of positive polarity which is applied to the maintenance only electrodes E1 to E4, while at the same time, a slot CBe of opposite polarity, that is to say ie negative, is applied to the addressing-maintenance electrodes Y1 to Y4; but this slot Cbe reaches a value VY2 lower than the value VY1, and it retains this value VY2 until an instant t7 when the polarity of the voltage VY reverses again.
- the transition of the slot CBe applied to the addressing-maintenance electrodes Y1 to Y4 has a value ⁇ VY2 lower than the value ⁇ VY1 of a maintenance slot CEY, so that the potential developed between the maintenance electrodes Y1 to Y4 and E1 to E4 is insufficient to cause a maintenance discharge, even when it is added to the effect of charges already stored on these maintenance electrodes.
- the slots applied to the addressing-maintenance electrodes Y1 to Y4 at time t4, are intended to form a voltage base or step called the erasing base slot CBe which is superimposed, only on the slot applied to the electrode addressing-maintenance of the pair P1 to P4 addressed (namely in this case only the slot applied to the second addressing-maintenance electrode Y2), a voltage pulse called erase pulse IE, IE '.
- the erasure pulse may have the form of a rectangular slot having either a high amplitude and a short duration, or a low amplitude and a long duration, or even be formed of a pulse whose rising edge is established relatively slowly and constitutes a ramp, as explained in the patent application No. 78 04893 cited above, filed in the name of THOMSON-CSF and published under No. FR-A-2 417 848, and which must be considered to be part of this description.
- the erasing pulse IE (shown in dashed lines) which is superimposed on the erasing base slot CBe, is a pulse whose rising edge R is established relatively slowly as described in the aforementioned patent, until substantially reaching the first value VY1; but the erasing pulse could also be constituted by an IE ′ pulse (shown in dashed lines) of relatively short duration, and which would be superimposed on the erasing basic slot CBE from for example from time t4.
- the niche erasing IE, IE ' is superimposed on a basic erasing slot CBe only for the pair of electrodes P1 to P4 addressed; taking into account the example described, it is only to the second addressing electrode Y2 that an erasing base slot CBe is applied to which an erasing pulse IE, IE ′ is superimposed.
- the erase pulse is the one whose rising edge constitutes a ramp R
- the superposition of this erase pulse IE with the basic slot CBe will cause substantially at time t5 when the ramp R reaches substantially the first value VY1, an erasure discharge DEF between the second addressing-maintenance electrode Y2 and the second solely maintenance electrode E2, at the level of each pixel.
- This erasure discharge is of lower intensity than the maintenance discharges DE1, DE2, and substantially ceases at an instant t6 without causing the accumulation of charges as in the case of the maintenance discharges DE1, DE2. In this configuration, all the pixels PX5 to PX8 of the second pair P2 are erased.
- an important characteristic of the process of the invention consists in generating an erasure discharge only between the two maintenance electrodes Y2, E2 of the same given pair P2, this erasure discharge DEF having the effect to erase all the pixels which correspond to this pair P2 of electrodes.
- the desired pixels belonging to the registration are carried out to this pair P2 of electrodes, by causing a writing discharge between the second addressing-maintenance electrode Y2 and each of the column electrodes X1 to X4 whose intersection with the second addressing-maintenance electrode Y2 represents a pixel that we want to register.
- a writing discharge is carried out only between the second addressing-maintenance electrode Y2 and the third column electrode X3. This is done during the registration phase T2 which begins at time t8.
- This stabilization depends on characteristics specific to the plasma panel used, so that the time interval ⁇ t1 can possibly be reduced or even eliminated, which makes it possible to reduce the duration of the period T (which represents the basic cycle).
- This basic cycle can have an even shorter duration, as represented for example by the duration T ′, by eliminating the slots which belong to the maintenance phase T3; this is made possible by the fact that even by eliminating the maintenance phase T3, it is possible with the method of control in accordance with the invention obtain maintenance discharges by the T2 registration phase.
- the voltage VE becomes negative; the voltage VY becomes positive by a voltage pulse CBi applied to the addressing-maintenance electrodes Y1 to Y4; the voltage VY then passes to the value VY1, that is to say a variation ⁇ VY1 by which it is possible to obtain maintenance discharges for all the pixels entered. So for example if we had not erased the sixth pixel P6 (at the same time as the other pixels of the second line L2), we would have kept charges on the electrodes Y2 and E2 which would have allowed to produce a discharge of 'interview De3 (shown in dotted lines) at time t8.
- a registration window CI is superimposed on the voltage window CBi which, between time t8 and time t12, is applied to all the electrodes d addressing-interview.
- a registration slot CI is only superimposed on the basic registration slot CBi which is applied to the desired address, that is to say to the address-maintenance electrode of the pair of electrodes in question, namely in the example the second addressing-maintenance electrode Y2 of the second pair 2.
- the voltage slot CBi thus constitutes a basic recording slot forming a voltage step at which s adds the voltage of the CI registration window; but it also constitutes a maintenance window for the pairs P1, P3, P4 of the other addressing-maintenance electrodes Y1, Y3, Y4, not addressed.
- the registration window CI superimposed on the basic registration window CBI reaches a voltage value VY3 such that the potential difference which is then generated between the column electrodes X1 to X4 and the second addressing-maintenance electrode Y2 can cause a discharge, called registration discharge, at the intersection between the latter and the column electrodes X1 to X4.
- a voltage pulse called the masking pulse MX1 to MX4 of the same polarity as the writing slot CI; so that the potential necessary to produce a discharge between a column electrode X1 to X4 and the electrode Y2, is reached only with the column electrode to which a so-called masking pulse is not applied.
- a masking pulse is applied to all of the column electrodes X1 to X4, none of the pixels are registered. In the nonlimiting example described, and as illustrated in FIGS.
- the column electrodes X1 to X4 are brought to the potential of the reference voltage VR, except during the writing phase T2 where a pulse of masking can be applied to them, which brings their voltage to a VX value.
- a masking pulse MX1, MX2, MX4 is applied to the first, the second and the fourth column electrode X1, X2, X4 , for at least and a masking pulse is not applied to the third column electrode X3.
- the end of the registration slot CI occurs substantially at the same time as the end of the registration base slot CBi, at a time t11 which for example slightly precedes the time t12 at the end of the registration base slot CBi.
- the potential difference between these two electrodes is reduced by reversing the polarity of the voltage VE applied to the electrodes E1 to E4 before the CI registration window is superimposed on the basic registration window CBi: from time t8, the voltage VE goes from positive to negative and constitutes a window CNE of negative polarity; then the polarity of the voltage VE (applied to the maintenance only electrodes E1 to E4) is again inverted at an instant t9 and comprises a positive polarity, this substantially at the same time or a little before the registration window begins.
- the voltage VE then has the same polarity as the voltage VY applied to the address-maintenance electrodes and, between the second maintenance electrode E2 and the second address-maintenance electrode Y2, then there is an insufficient potential difference to cause a parasitic discharge during the superimposition of the CI registration window.
- an advantage brought by this arrangement resides in the fact that, the masking pulses MX1 to MX4 are produced with a relatively low power (because it is with the maintenance discharges that one seeks to produce the light emitted by the pixels, and with a relatively low voltage amplitude), so that standard and low-cost components can be used for controlling the column electrodes X1 to X4. It is further noted that another important advantage provided by the method according to the invention, resides in that the discharge which is created occurs only for the points to be entered and not for all the points of the line, which tends to significantly increase the longevity of the phosphors which are used for the emission of color light.
- the end of the basic registration window CBi corresponds to the end of the registration phase T2, and corresponds to an inversion of the polarity of the voltage VY applied to the addressing-maintenance electrodes Y1 to Y4, polarity which becomes negative.
- the voltage VE applied to the maintenance electrodes E1 to E4 has been positive since substantially the instant t9 and, in the nonlimiting example described, it retains this positive polarity until an instant t0 'which marks the start of a new cycle.
- the DI registration discharge generated the accumulation of negative charges (not shown) on the dielectric of the second addressing-maintenance electrode Y2 at the level of the seventh pixel PX7: also at the transition from positive to negative of the voltage VY, due to the end of the writing window CI and the basic writing window CBi, is added the effect of the presence of the negative charges accumulated on the electrode Y2 so that, appreciably when the voltage VY reaches the value -Vy1, there is a maintenance resumption discharge DRE (FIG. 3c) at the seventh pixel PX7, between the second addressing-maintenance electrode Y2 and the second maintenance electrode E2.
- DRE maintenance resumption discharge
- the voltages VY and VE keep their negative and positive polarity respectively until time t0 'where begins a new cycle. It should be noted that, depending on the characteristics specific to the plasma panel used, it is possible that a discharge (shown in dotted lines in FIG. 3h) occurs substantially at time t12 between the column electrode X3 and the electrode addressing-interview Y2; in such a case, a maintenance resumption discharge DRE '(shown in dotted lines in FIG. 3c) occurs at the instant t0' of the start of a new cycle.
- the basic cycle is applied to all the maintenance electrodes with a frequency which depends on the duration of the period T, T '.
- the duration of a period T, T 'can hardly fall below 22 microseconds or 20 microseconds. This nevertheless makes it possible to obtain very interesting performances even with a plasma panel comprising a large number of lines. Taking for example a plasma panel comprising 1000 lines, it takes 20 milliseconds to explore an entire image, that is to say it is possible to obtain 50 images per second.
- the CEY and CEe maintenance slots have a conventional duration of the order of a few microseconds; the basic erasing slot CBe can have a duration of the order of 5 microseconds; the time interval ⁇ t1 can be of the order of 3 to 4 microseconds.
- the basic CBi registration slot can have a duration of the order of 7 microseconds; and the registration window Ci which is superimposed on it may have a duration of approximately 4 microseconds, and / or possibly have the same shape as the erasure pulse IE whose rising edge constitutes a ramp R, and whose duration at the top can be of the order of zero to a few microseconds; the niche negative marked CNE on the voltage VE can have a duration of the order of 3 microseconds.
- the negative slot CNE is followed by a positive slot (from time t9), this positive slot being formed, for its part formed between the end of the negative slot CNE and the time t12 at the end of the basic registration window, by a CME masking window which fulfills a function of inhibiting the registration window CI vis-à-vis the second maintenance-only electrode E2, in order to avoid a parasitic discharge between this second electrode E2 and the second addressing-maintenance electrode Y2.
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Description
La présente invention concerne un procédé de commande ligne par ligne d'un panneau à plasma du type alternatif à entretien coplanaire, et particulièrement d'un panneau à plasma dans lequel chaque point élémentaire d'image est défini sensiblement au croisement d'une première électrode dite "électrode colonne" avec deux autres électrodes parallèles appelées "électrodes d'entretien".The present invention relates to a method of line-by-line control of a plasma panel of the alternative type with coplanar maintenance, and particularly of a plasma panel in which each elementary image point is defined substantially at the intersection of a first electrode. called "column electrode" with two other parallel electrodes called "maintenance electrodes".
Les panneaux à plasma sont des dispositifs de visualisation à écran plat, qui permettent l'affichage d'images alphanumériques, graphiques ou autres, en couleur ou non. Ces panneaux fonctionnent sur le principe d'une émission de lumière produite par une décharge électrique dans un gaz.Plasma panels are flat screen display devices, which allow the display of alphanumeric, graphic or other images, in color or not. These panels work on the principle of an emission of light produced by an electric discharge in a gas.
Généralement les panneaux à plasma comprennent deux dalles isolantes limitant un volume occupé par un gaz (généralement un mélange à base de néon). Ces dalles supportent des électrodes conductrices croisées de sorte à définir une matrice de points élémentaires d'images ou pixels. Une décharge électrique dans le gaz, provoquant une émission de lumière au niveau d'un point image ou pixel, a lieu lorsque les électrodes de ce pixel sont convenablement excitées.Generally plasma panels include two insulating tiles limiting a volume occupied by a gas (generally a mixture based on neon). These slabs support crossed conductive electrodes so as to define a matrix of elementary points of images or pixels. An electric discharge in the gas, causing an emission of light at the level of an image point or pixel, takes place when the electrodes of this pixel are suitably excited.
Bien que certains panneaux à plasma fonctionnent en continu, on préfère le plus souvent utiliser des panneaux du type alternatif dont le fonctionnement est basé sur une excitation en régime alternatif des électrodes. Les électrodes sont recouvertes d'une couche de matériau diélectrique. Elles ne sont donc plus en contact direct avec le gaz, ni avec la décharge.Although certain plasma panels operate continuously, it is most often preferred to use panels of the alternative type, the operation of which is based on an excitation in alternating mode of the electrodes. The electrodes are covered with a layer of dielectric material. They are therefore no longer in direct contact with the gas, nor with the discharge.
Le fonctionnement d'un panneau à plasma, de type alternatif à deux électrodes croisées pour définir un pixel, est connu notamment par un brevet français n° 78 04893 au nom de THOMSON-CSF, publié sous le n° FR-A-2 417 848. Ce brevet décrit en outre une méthode d'effacement des pixels d'un tel panneau ainsi que divers types de signaux qui sont appliqués aux cellules (espace gazeux compris entre deux électrodes croisées, c'est-à-dire au niveau du pixel) d'un panneau à plasma : notamment des signaux d'inscription, d'entretien et d'effacement :
- le signal d'inscription est constitué par une impulsion de tension, d'amplitude au moins égale à la tension d'amorçage, du gaz de la cellule. La cellule émet une brève impulsion de lumière, car les charges électriques créées par ionisation du gaz ne peuvent atteindre les électrodes qui sont isolées par des couches diélectriques. Ces charges se déposent sur les couches diélectriques et créent un champ électrique interne qui s'oppose au champ électrique induit par le signal d'inscription et qui croît jusqu'à provoquer l'extinction de la cellule ou pixel. La cellule conserve en mémoire le champ interne précédemment acquis, et elle est dite alors à l'état 1 ou état inscrit, alors qu'un pixel ayant un champ interne quasi nul est dit à l'état 0 ou état effacé. Ainsi le signal d'inscription permet la mise à l'état 1 des cellules ou pixels se trouvant à l'état 0.
- Le signal d'entretien mémorise l'information d'une cellule à l'état "inscrit". Ce signal d'entretien est constitué par une tension alternative qui rallume, deux fois par période, une cellule se trouvant déjà à l'état inscrit. Le champ interne conservé en mémoire par une cellule ou pixel à l'état inscrit permet de rallumer ce pixel par un signal d'entretien d'amplitude inférieure à la tension d'amorçage ; à chaque ionisation du gaz de la cellule ou pixel, provoquée par une décharge d'entretien, le champ interne s'annule et un champ interne de signe contraire au précédent vient charger la cellule ou pixel.
- Le signal d'effacement permet la mise à l'état 0 ou état effacé, d'une ou de plusieurs ou de toutes les cellules ou pixels du panneau. Le signal d'effacement ne modifie pas l'état des cellules se trouvant déjà à l'état 0. L'effacement d'une cellule consiste à provoquer un amorçage d'effacement, c'est-à-dire une ionisation du gaz de cette cellule avec par exemple une intensité juste suffisante pour annuler les charges accumulées sur les couches diélectriques au regard des électrodes. Ainsi par exemple il est connu d'effacer une cellule à l'état 1 en utilisant une impulsion de tension, calibrée en temps et en amplitude, qui ionise le gaz de la cellule et annule son champ interne, sans en engendrer un nouveau, au contraire de ce qui est obtenu avec un signal d'entretien. On peut utiliser à cet effet une impulsion de tension en forme de créneaux rectangulaires, ayant soit une forte amplitude et une durée brève, soit une faible amplitude et une longue durée.
- the registration signal consists of a voltage pulse, of amplitude at least equal to the ignition voltage, of the cell gas. The cell emits a short pulse of light, because the electric charges created by ionization of the gas cannot reach the electrodes which are isolated by dielectric layers. These charges are deposited on the dielectric layers and create an internal electric field which opposes the electric field induced by the registration signal and which increases until the cell or pixel goes out. The cell keeps in memory the internal field previously acquired, and it is then called in
state 1 or registered state, while a pixel having an internal field almost zero is said in state 0 or erased state. Thus, the registration signal enables cells or pixels in state 0 to be set tostate 1. - The maintenance signal stores the information of a cell in the "registered" state. This maintenance signal consists of an alternating voltage which re-ignites, twice per period, a cell already in the registered state. The internal field kept in memory by a cell or pixel in the registered state makes it possible to relight this pixel by a maintenance signal of amplitude lower than the ignition voltage; each time the cell or pixel gas is ionized, caused by a maintenance discharge, the internal field is canceled and an internal field of sign contrary to the previous one comes to charge the cell or pixel.
- The erasure signal allows the setting to state 0 or erased state, of one or more or all the cells or pixels of the panel. The erasure signal does not modify the state of the cells already in state 0. The erasure of a cell consists in causing an erasure initiation, that is to say an ionization of the gas. this cell with, for example, an intensity just sufficient to cancel the charges accumulated on the dielectric layers with regard to the electrodes. Thus, for example, it is known to erase a cell in
state 1 by using a voltage pulse, calibrated in time and in amplitude, which ionizes the gas of the cell and cancels its internal field, without generating a new one, at the contrary to what is obtained with a maintenance signal. One can use for this purpose a voltage pulse in the form of rectangular slots, having either a high amplitude and a short duration, or a low amplitude and a long duration.
La demande de brevet ci-dessus citée explique en outre comment réaliser l'effacement, d'une ou plusieurs cellules, à l'aide d'un signal d'effacement dont le front de montée est constitué par une rampe.The aforementioned patent application also explains how to erase one or more cells, using an erasure signal, the rising edge of which is constituted by a ramp.
En vue notamment d'améliorer la luminance des panneaux à plasma, et aussi de permettre l'affichage de plusieurs couleurs, on préfère utiliser des panneaux à plasma du type excités en régime alternatif comme ci-dessus décrit, et qui en outre sont à entretien coplanaire. Dans ce dernier type de panneaux dits alternatifs à entretien coplanaire, chaque pixel de la matrice est constitué par trois électrodes, plus précisément au croisement entre une électrode d'adressage dite électrode colonne avec deux électrodes d'entretien parallèles formant une paire d'électrodes d'entretien. Dans ce type d'écran, l'entretien des décharges est assuré entre les deux électrodes d'une même paire, et l'adressage se fait par génération de décharge entre deux électrodes croisées ; par adressage on entend des décharges engendrées de manière sélective et/ou demi-sélective en vue de réaliser une opération d'inscription ou d'effacement.With a view in particular to improving the luminance of the plasma panels, and also to allow the display of several colors, it is preferred to use plasma panels of the type excited in alternating mode as described above, and which in addition are maintenance coplanar. In this latter type of so-called alternative panels with coplanar maintenance, each pixel of the matrix is constituted by three electrodes, more precisely at the intersection between an addressing electrode called column electrode with two parallel maintenance electrodes forming a pair of electrodes d 'interview. In this type of screen, the maintenance of the discharges is ensured between the two electrodes of the same pair, and the addressing is done by generation of discharge between two crossed electrodes; by addressing is meant discharges generated so selective and / or semi-selective with a view to carrying out a registration or deletion operation.
Ainsi les électrodes d'entretien comportent deux familles : on appelle les électrodes d'une première famille "électrodes d'adressage-entretien" et les électrodes de la seconde famille "électrodes uniquement d'entretien". Les électrodes d'adressage entretien ont pour fonction, en coopération avec les électrodes uniquement d'entretien (de la seconde famille) d'assurer les décharges d'entretien ; mais elles ont aussi à assurer une fonction d'adressage, et de ce fait, elles doivent être individualisées c'est-à-dire qu'elles doivent, par exemple, être reliées à un ou des dispositifs générateurs d'impulsions par l'intermédiaire de moyens qui permettent d'appliquer une ou des impulsions particulières, à seulement une ou plusieurs électrodes d'adressage-entretien qui sont sélectionnées parmi la pluralité d'électrodes d'adressage-entretien.Thus the maintenance electrodes comprise two families: the electrodes of a first family are called "addressing-maintenance electrodes" and the electrodes of the second family "electrodes only of maintenance". The maintenance addressing electrodes have the function, in cooperation with the maintenance only electrodes (of the second family), of ensuring maintenance discharges; but they also have to provide an addressing function, and therefore they must be individualized, that is to say that they must, for example, be connected to one or more pulse generating devices by the intermediary of means which make it possible to apply one or more particular pulses, to only one or more address-maintenance electrodes which are selected from the plurality of address-maintenance electrodes.
Bien entendu les électrodes colonnes sont également individualisées.Of course, the column electrodes are also individualized.
En ce qui concerne les électrodes uniquement d'entretien (seconde famille), celles-ci sont généralement reliées à un ou des générateurs d'impulsions de telle manière que ces électrodes d'entretien de la seconde famille sont toutes, aux mêmes instants, portées à des mêmes potentiels de sorte qu'il n'est pas nécessaire de les individualiser et qu'elles peuvent éventuellement être reliées entre elles.As regards the maintenance only electrodes (second family), these are generally connected to one or more pulse generators in such a way that these maintenance electrodes of the second family are all, at the same times, brought to the same potentials so that it is not necessary to individualize them and that they can possibly be linked together.
Parmi les avantages apportés par les structures où un pixel est défini au croisement d'une électrode colonne avec une paire d'électrodes d'entretien, on peut citer une plus grande luminance, qui tient au fait notamment que les décharges d'entretien entre les deux électrodes d'entretien s'effectuent sur une surface qui déborde la surface d'intersection avec l'électrode colonne ; de sorte que la lumière utile n'est pas bloquée par cette électrode colonne qui généralement est montée du côté de la dalle par laquelle on regarde le panneau à plasma. Il est à noter que les électrodes d'adressage-entretien et uniquement d'entretien peuvent comporter chacune, au niveau de chaque pixel, une protubérance ou surface saillante ; dans une même paire d'électrodes d'entretien, les surfaces saillantes d'une électrode sont orientées vers celles de l'autre électrode, les décharges d'entretien s'effectuant entre ces surfaces saillantes.Among the advantages provided by structures where a pixel is defined at the intersection of a column electrode with a pair of maintenance electrodes, one can cite a greater luminance, which is due in particular to the fact that the maintenance discharges between the two maintenance electrodes are carried out on a surface which projects beyond the surface of intersection with the column electrode; so that the useful light is not blocked by this column electrode which is generally mounted on the side of the panel through which the plasma panel is viewed. It should be noted that the addressing-maintenance and only maintenance electrodes may each include, at the level of each pixel, a protrusion or protruding surface; in the same pair of maintenance electrodes, the projecting surfaces of one electrode are oriented towards those of the other electrode, the maintenance discharges taking place between these projecting surfaces.
Un tel écran à plasma est connu notamment du document de brevet européen EP-A-0 135 382 qui décrit également un procédé de commande de cet écran ; il est à noter que dans le dispositif décrit dans ce brevet européen, l'électrode colonne croise les paires d'électrodes d'entretien sur le côté des surfaces saillantes où sont produites les décharges d'entretien.Such a plasma screen is known in particular from the European patent document EP-A-0 135 382 which also describes a method for controlling this screen; it should be noted that in the device described in this European patent, the column electrode crosses the pairs of maintenance electrodes on the side of the projecting surfaces where the maintenance discharges are produced.
Une autre structure du type dans laquelle chaque pixel est défini au croisement d'une électrode colonne avec une paire d'électrodes d'entretien ainsi qu'un procédé de commande adapté sont décrits dans l'article de G. W. DICK publié dans PROCEEDINGS OF THE SID, vol. 27/3, 1986, pages 183-187. Il est à noter que dans la structure décrite dans ce document, les électrodes d'entretien ont une largeur constante, c'est-à-dire qu'elles ne comportent pas de surface saillante en vis-à-vis dans une paire d'électrode d'entretien, pour définir la zone de décharge d'entretien, cette structure comporte par contre des barrières en matériau isolant, qui servent à confiner des décharges d'entretien dans la zone de croisement avec l'électrode colonne.Another structure of the type in which each pixel is defined at the intersection of a column electrode with a pair of maintenance electrodes and a suitable control method are described in the article by GW DICK published in PROCEEDINGS OF THE SID , flight. 27/3, 1986, pages 183-187. It should be noted that in the structure described in this document, the maintenance electrodes have a constant width, that is to say that they do not have a projecting surface facing one another in a pair of maintenance electrode, to define the maintenance discharge zone, this structure on the other hand comprises barriers made of insulating material, which serve to confine maintenance discharges in the crossing zone with the column electrode.
Un autre type de panneau à plasma, auquel le procédé de l'invention s'applique de manière particulièrement intéressante, est représenté sur la figure 1. Un tel panneau fait l'objet en soi, d'une demande de brevet français n° 88 03953 déposée le 25 Mars 1988 au nom de THOMSON-CSF. Cette demande de brevet français a été publiée sous le n° FR-A- 2 629 265, le type nouveau de panneau à plasma auquel elle se rapporte est décrit ci-après.Another type of plasma panel, to which the method of the invention applies in a particularly advantageous manner, is represented in FIG. 1. Such a panel is the subject in itself of a French patent application No. 88 03953 filed March 25, 1988 on behalf of THOMSON-CSF. This French patent application was published under the number FR-A-2 629 265, the new type of plasma panel to which it relates is described below.
Le panneau représenté sur la figure 1 comprend une première dalle de verre 10 recouverte d'une première famille d'électrodes notée Xj, où j est un entier allant de 1 à N (une seule électrode Xj est représentée ; l'ensemble dalle 10-électrode Xj est recouvert d'une couche 12 de matériau diélectrique, éventuellement recouvert d'une couche d'oxyde tel que MgO (non représentée) facilitant l'émission électronique. Sur la couche diélectrique 12 se trouve une pastille 14 d'un matériau luminophore, c'est-à-dire apte à émettre un rayonnement coloré, sous l'effet d'un rayonnement ultra-violet.The panel shown in FIG. 1 comprises a
Le panneau comprend encore une seconde dalle de verre 20 recouverte d'une seconde famille d'électrodes constituées de paires d'électrodes dites respectivement, d'entretien-adressage (Yae)i et d'entretien (Ye), où i est un entier compris entre 1 et P. Les électrodes d'entretien-adressage et d'entretien comprennent des protubérances ou surfaces en saillie 22 et 24, disposées en regard les unes des autres. L'ensemble dalle 20-électrodes est recouvert d'une couche diélectrique 26.The panel also comprises a
En fonctionnement normal, les deux dalles 10 et 20 et leurs réseaux d'électrodes sont rapprochés et tenus écartés par une cale d'épaisseur (non représentée), et un gaz est présent dans le volume compris entre les dalles et la cale. Le panneau une fois monté présente ainsi deux réseaux d'électrodes orthogonales, en ce sens que les électrodes Xj sont orthogonales aux électrodes (Yae)i et (Ye). Les électrodes Xj peuvent chevaucher les protubérances 22 et 24 ou être légèrement décalées sur le côté de celles-ci. Un pixel Pij est défini alors par une électrode Xj (électrode colonne) et une paire d'électrodes d'entretien (Yae)i et (Ye).In normal operation, the two
Si l'on commande le panneau à plasma ci-dessus décrit où les autres panneaux à plasma précédemment cités, par un procédé de commande connu, le fonctionnement de ces panneaux à plasma peut comporter un ou plusieurs des défauts ci-après mentionnés :
- les impulsions appliquées aux différentes électrodes peuvent comporter de nombreux niveaux de tensions, d'où il résulte une complication des générateurs d'impulsions et du nombre de moyens d'adressage sélectif ;
- durée longue du cycle total, d'où il peut résulter une incompatibilité au fonctionnement dans des systèmes rapides, de type vidéo par exemple (par analogie aux images produites par des tubes à rayons cathodiques où ne image est définie ligne par ligne) et d'où il peut résulter une luminance faible due à la fréquence faible des décharges d'entretien ;
- l'inscription et/ou l'effacement des pixels exige plusieurs décharges avec l'électrode colonne, d'où il peut résulter une dégradation fortement accélérée des luminophores (utilisés dans les technologies les plus récentes pour modifier la coloration de la lumière émise).
- the pulses applied to the different electrodes can have many voltage levels, which results in a complication of the pulse generators and the number of selective addressing means;
- long duration of the total cycle, from which there may result an incompatibility in operation in fast systems, of the video type for example (by analogy to the images produced by cathode ray tubes where no image is defined line by line) and where it may result in low luminance due to the low frequency of maintenance discharges;
- the recording and / or the erasing of the pixels requires several discharges with the column electrode, from where it can result a strongly accelerated degradation of the phosphors (used in the most recent technologies to modify the coloration of the emitted light).
Le procédé de commande selon l'invention permet d'éliminer ou de diminuer considérablement les inconvénients ci-dessus cités. Le procédé de commande proposé est du type compatible vidéo, c'est-à-dire qui permet un adressage par ligne complète de sorte à réduire le temps de balayage ; il autorise d'autre part un temps de cycle réduit d'où il résulte une fréquence d'entretien élevée et une luminance élevée. Le procédé de commande proposé permet également de diminuer le nombre de niveaux de tensions appliquées aux différentes électrodes et de simplifier ainsi l'électronique de commande ; il est à noter que le procédé de l'invention permet en outre de n'appliquer sur l'électrode colonne que des impulsions de puissance et d'amplitude relativement faibles ce qui autorise l'utilisation de circuits intégrés d'une technologie à faible coût.The control method according to the invention makes it possible to eliminate or considerably reduce the drawbacks mentioned above. The proposed control method is of the video compatible type, that is to say which allows addressing by complete line so as to reduce the scanning time; on the other hand, it allows a reduced cycle time which results in a high maintenance frequency and a high luminance. The proposed control method also makes it possible to reduce the number of voltage levels applied to the different electrodes and thus to simplify the control electronics; it should be noted that the method of the invention also makes it possible to apply to the column electrode only relatively low power and amplitude pulses which allows the use of integrated circuits of low cost technology .
Selon l'invention, un procédé de commande ligne par ligne d'un panneau à plasma du type alternatif à entretien coplanaire, ledit panneau comprenant des électrodes colonnes croisées avec deux familles d'électrodes d'entretien parallèles, la première famille d'électrodes étant constituée par des électrodes d'adressage-entretien et la seconde famille étant constituée par des électrodes uniquement d'entretien, chaque électrode d'adressage-entretien formant avec une électrode uniquement d'entretien voisine une paire d'électrodes d'entretien, chaque paire d'électrodes d'entretien correspondant à une ligne de pixels perpendiculaire aux électrodes colonnes, les pixels étant formés sensiblement à chaque croisement d'une électrode colonne avec une paire d'électrodes d'entretien, ledit procédé consistant à appliquer un premier jeu d'impulsions cycliques à toutes les électrodes d'adressage-entretien et un deuxième jeu d'impulsions cycliques à toutes les électrodes dites uniquement d'entretien, les deux jeux d'impulsions ayant une même période, durant laquelle lesdites implusions développent entre les deux électrodes de chaque paire d'électrodes d'entretien des tensions qui constituent une phase d'effacement et une phase d'inscription survenant après la phase d'effacement, lesdites tensions engendrant en outre des décharges d'entretien, ledit procédé consistant à effacer une ligne complète donnée de pixels durant la phase d'effacement en provoquant des décharges d'effacement uniquement entre l'électrode d'adressage-entretien et l'électrode dite uniquement d'entretien de la paire d'électrodes d'entretien correspondante.According to the invention, a method of line-by-line control of a plasma panel of the alternative type with coplanar maintenance, said panel comprising crossed column electrodes with two families of parallel maintenance electrodes, the first family of electrodes being made up of addressing-maintenance electrodes and the second family consisting of maintenance-only electrodes, each addressing-maintenance electrode forming with a maintenance-only electrode adjoining a pair of maintenance electrodes, each pair of electrodes maintenance corresponding to a line of pixels perpendicular to the column electrodes, the pixels being formed substantially at each crossing of a column electrode with a pair of maintenance electrodes, said method consisting in applying a first set of cyclic pulses to all the addressing-maintenance electrodes and a second set of cyclic pulses to all the so-called maintenance-only electrodes, the two sets of pulses having the same period, during which said implusions develop between the two electrodes of each pair of '' voltage maintenance electrodes which constitute an erasure phase and a registration phase occurring after the phase erase, said voltages further generating maintenance discharges, said method consisting in erasing a given complete line of pixels during the erasing phase by causing erasure discharges only between the addressing-maintenance electrode and the so-called maintenance only electrode of the corresponding pair of maintenance electrodes.
L'invention sera mieux comprise à l'aide de la description qui suit, faite à titre d'exemple non limitatif, en référence aux dessins annexés dans lesquels :
- la figure 1 déjà décrite montre un nouveau type de panneau à plasma auquel l'invention peut s'appliquer ;
- la figure 2 montre de manière schématique un panneau à plasma auquel le procédé de l'invention peut s'appliquer ;
- les figures 3a à 3h montrent des signaux qui expliquent le fonctionnement du panneau à plasma montré à la figure 2 et commandé par le procédé conforme à l'invention ;
- Figure 1 already described shows a new type of plasma panel to which the invention can be applied;
- FIG. 2 schematically shows a plasma panel to which the method of the invention can be applied;
- Figures 3a to 3h show signals which explain the operation of the plasma panel shown in Figure 2 and controlled by the method according to the invention;
La figure 2 est un schéma de principe général d'un panneau à plasma 1 auquel peut s'appliquer le procédé de commande de l'invention. Pour plus de clarté de la figure le panneau à plasma 1 est représenté principalement par des conducteurs ou électrodes disposés en colonne X1, X2, X3, X4, et par deux familles de conducteurs ou électrodes d'entretien disposés en ligne, d'une part Y1, Y2, Y3, Y4 pour la première famille, et d'autre part, E1, E2, E3, E4 pour la seconde famille.FIG. 2 is a general block diagram of a
Les électrodes d'entretien Y1 à Y4 et E1 à E4 sont disposées par paire, c'est-à-dire qu'une première électrode Y1 de la première famille est associée avec une électrode E1 voisine appartenant à la seconde famille, pour constituer une paire P1 d'électrodes d'entretien ; une seconde électrode Y2 de la première famille est associée avec une seconde électrode E2 de la seconde famille pour constituer une seconde paire P2 d'électrodes d'entretien ; et de même pour les électrodes Y3 et E3 puis Y4 et E4 qui constituent respectivement une troisième et une quatrième paire P3, P4 d'électrodes d'entretien. A chaque croisement d'une électrode colonne X1 à X4 avec une paire d'électrodes P1 à P4 est constitué un point élémentaire d'image ou pixel PX1 à PX16 qui est symbolisé sur la figure 2 par un cercle en traits pointillés ; chaque pixel pouvant être formé par exemple selon la structure représentée à la figure 1 et les deux électrodes de chaque paire d'électrodes P1 à P4 peuvent comporter ou non des protubérances ou parties saillantes (non représentées sur la figure 2) montrées à la figure 1 avec les repères 22, 24.The maintenance electrodes Y1 to Y4 and E1 to E4 are arranged in pairs, that is to say that a first electrode Y1 of the first family is associated with an adjacent electrode E1 belonging to the second family, to constitute a pair P1 of maintenance electrodes; a second electrode Y2 of the first family is associated with a second electrode E2 of the second family to constitute a second pair P2 of maintenance electrodes; and likewise for the electrodes Y3 and E3 then Y4 and E4 which respectively constitute a third and a fourth pair P3, P4 of maintenance electrodes. At each crossing of a column electrode X1 to X4 with a pair of electrodes P1 to P4, an elementary image point or pixel PX1 to PX16 is formed which is symbolized in FIG. 2 by a circle in dotted lines; each pixel which can be formed for example according to the structure represented in FIG. 1 and the two electrodes of each pair of electrodes P1 to P4 may or may not have protuberances or projecting parts (not shown in FIG. 2) shown in FIG. 1 with the
Dans l'exemple non limitatif décrit, et pour plus de clarté de la figure, seulement 4 électrodes de chaque type ont été représentées de sorte que seulement 16 pixels PX1 à PX16 sont constitués, mais bien entendu l'arrangement matriciel de pixels peut être beaucoup plus important, constitué par exemple par les croisements de 1 024 électrodes en colonne avec 1 024 paires d'électrodes d'entretien, chaque paire comportant une électrode de la première famille Y avec une électrode de la seconde famille E.In the nonlimiting example described, and for clarity of the figure, only 4 electrodes of each type have been represented so that only 16 pixels PX1 to PX16 are formed, but of course the matrix arrangement of pixels can be much more important, constituted for example by the crossings of 1024 column electrodes with 1024 pairs of maintenance electrodes, each pair comprising an electrode of the first family Y with an electrode of the second family E.
Les électrodes Y1 à Y4 de la première famille sont des électrodes du type adressage-entretien, aussi ces électrodes d'adressage-entretien Y1 à Y4 sont individualisées, c'est-à-dire qu'elles sont chacune reliées à une sortie différente SY1 à SY4 d'un premier dispositif d'adressage G1 ; le premier dispositif d'adressage G1 est d'un type en lui-même classique capable de fournir des impulsions de tension qui seront davantage expliquées en référence à la figure 3a. Les électrodes E1 à E4 de la seconde famille E sont du type électrodes uniquement d'entretien : dans l'exemple non limitatif décrit, elles sont reliées entre elles et reliées à la sortie SE d'un dispositif générateur d'impulsions G2 qui délivre des impulsions de tension qui seront davantage explicitées en référence à la figure 3b.The electrodes Y1 to Y4 of the first family are address-maintenance type electrodes, so these address-maintenance electrodes Y1 to Y4 are individualized, that is to say that they are each connected to a different output SY1 to SY4 of a first addressing device G1; the first addressing device G1 is of a conventional type in itself capable of supplying voltage pulses which will be further explained with reference to FIG. 3a. The electrodes E1 to E4 of the second family E are of the maintenance only type: in the non-limiting example described, they are connected together and connected to the output SE of a pulse generator device G2 which delivers voltage pulses which will be explained more clearly with reference to FIG. 3b.
Les électrodes colonnes X1 à X4 assurent de manière classique, uniquement un rôle d'adressage. Elles sont chacune reliées à une sortie différente SX1 à SX4 d'un second dispositif d'adressage G3 ; le second dispositif d'adressage G3 délivre des impulsions de tension qui seront également explicitées dans une suite de la description relative aux figures 3d à 3g.Column electrodes X1 to X4 conventionally perform only an addressing role. They are each connected to a different output SX1 to SX4 of a second addressing device G3; the second addressing device G3 delivers voltage pulses which will also be explained in a continuation of the description relating to Figures 3d to 3g.
Les dispositifs G1, G2, G3 sont eux-mêmes commandés et synchronisés, de manière classique, par une unité centrale de commande (non représentée) qui gère d'une manière en elle-même connue l'allumage ou l'extinction ou le maintien allumé ou éteint des pixels PX1 à PX16.The devices G1, G2, G3 are themselves controlled and synchronized, in a conventional manner, by a central control unit (not shown) which manages in a known manner itself the switching on or off or the maintenance pixels PX1 to PX16 on or off.
Le procédé de commande conforme à l'invention permet d'effectuer une commande ligne par ligne : une ligne L1 à L4 est une ligne de pixels constituée par les pixels PX1 à PX16 définis par chaque paire P1 à P4 d'électrodes d'entretien : ainsi la première ligne L1 contient les 4 pixels PX1 à PX4, et correspond à la paire P1 d'électrodes d'entretien ; la seconde ligne L2 contient 4 pixels PX5 à PX8 et correspond à la seconde paire P2 d'électrodes ; la troisième ligne L3 contient les pixels PX9 à PX12 et correspond à la troisième paire P3 d'électrodes ; la quatrième ligne L4 contient les pixels PX13 à PX16 et correspond à la quatrième paire P4.The control method according to the invention makes it possible to carry out a control line by line: a line L1 to L4 is a line of pixels formed by the pixels PX1 to PX16 defined by each pair P1 to P4 of maintenance electrodes: thus the first line L1 contains the 4 pixels PX1 to PX4, and corresponds to the pair P1 of maintenance electrodes; the second line L2 contains 4 pixels PX5 to PX8 and corresponds to the second pair P2 of electrodes; the third line L3 contains the pixels PX9 to PX12 and corresponds to the third pair P3 of electrodes; the fourth line L4 contains the pixels PX13 to PX16 and corresponds to the fourth pair P4.
Les figures 3a à 3h montrent des diagrammes de signaux explicatifs du fonctionnement du panneau à plasma 1 commandés selon le procédé de l'invention.FIGS. 3a to 3h show diagrams of signals explaining the operation of the
Pour illustrer le fonctionnement qui est obtenu, on montre à titre d'exemple non limitatif les signaux qui sont appliqués quand on veut successivement éteindre un pixel et en allumer un autre : ainsi par exemple, sur la seconde ligne L2, éteindre (c'est-à-dire effacer) le sixième pixel PX6, et allumer (c'est-à-dire) inscrire le septième pixel PX7. On remarque que le sixième pixel PX6 est situé à l'intersection entre la seconde paire d'électrodes PE2 et la seconde électrode colonne X2 ; et que le septième pixel PX7 est situé à l'intersection entre la seconde paire d'électrodes PE2 et la troisième électrode colonne X3.To illustrate the operation which is obtained, we show by way of nonlimiting example the signals which are applied when we want to successively turn off one pixel and turn on another: thus for example, on the second line L2, turn off (this is i.e. erase) the sixth PX6 pixel, and turn on (i.e.) write the seventh PX7 pixel. Note that the sixth pixel PX6 is located at the intersection between the second pair of PE2 electrodes and the second column electrode X2; and that the seventh pixel PX7 is located at the intersection between the second pair of electrodes PE2 and the third column electrode X3.
Les figures 3a et 3b montrent respectivement un premier et un second jeu de tensions cycliques VY, VE qui sont appliquées respectivement simultanément à toutes les électrodes d'adressage-entretien Y1 à Y4 et simultanément à toutes les électrodes uniquement d'entretien E1 à E4. La figure 3c illustre des décharges d'entretien produites entre les électrodes Y2 et E2 de la seconde paire P2 d'électrodes. Les figures 3d, 3e, 3f, 3g, montrent respectivement des impulsions de tension formant des impulsions de masquage appliquées aux électrodes colonnes X1 à X4.FIGS. 3a and 3b respectively show a first and a second set of cyclic voltages VY, VE which are applied respectively simultaneously to all the addressing-maintenance electrodes Y1 to Y4 and simultaneously to all the maintenance-only electrodes E1 to E4. FIG. 3c illustrates maintenance discharges produced between the electrodes Y2 and E2 of the second pair P2 of electrodes. Figures 3d, 3e, 3f, 3g respectively show voltage pulses forming masking pulses applied to the column electrodes X1 to X4.
La figure 3 h illustre une décharge d'inscription DI entre la troisième électrode colonne X3 et la seconde électrode Y2.FIG. 3 h illustrates a DI registration discharge between the third column electrode X3 and the second electrode Y2.
Le premier et le second jeux de tensions VY, VE, varient de part et d'autre d'une même tension de référence VR qui est à zéro volt par exemple.The first and second sets of voltages VY, VE, vary on either side of the same reference voltage VR which is at zero volts for example.
Les premier et second jeux de tension VY, VE, sont constitués respectivement par un premier et un second jeux d'impulsions de tension ayant un caractère cyclique et une même période T. Durant cette période T, la combinaison des impulsions de tension appliquées d'une part aux électrodes d'adressage-entretien Y1 à Y4, et, d'autre part, aux électrodes uniquement d'entretien E1 à E4, développe entre les 2 électrodes de chaque paire P1 à P4 des tensions (non représentées) qui déterminent une phase d'effacement T1 et une phase d'inscription T2. Dans l'exemple non limitatif décrit, les cycles T comprennent en outre une phase d'entretien T3 qui est facultative, comme il est davantage expliqué dans la suite de la description.The first and second sets of voltage VY, VE, are constituted respectively by a first and a second set of voltage pulses having a cyclic character and a same period T. During this period T, the combination of the applied voltage pulses of on the one hand to the address-maintenance electrodes Y1 to Y4, and, on the other hand, to the electrodes only maintenance E1 to E4, develops between the 2 electrodes of each pair P1 to P4 voltages (not shown) which determine an erasing phase T1 and a writing phase T2. In the nonlimiting example described, the cycles T also include a maintenance phase T3 which is optional, as is explained further in the description below.
Dans la phase d'entretien T3, les tensions VY et VE ont des polarités opposées. Ainsi par exemple à la figure 3b à l'instant t0, débute un créneau d'entretien CEe qui est appliqué aux électrodes uniquement d'entretien E1 à E4, et dont la transition représente une variation de tension Δ VE qui dans l'exemple s'effectue de manière sensiblement symétrique par rapport à la tension référence VR ; ce premier créneau CEe d'entretien appliqué aux électrodes uniquement d'entretien E1 à E4 passant par exemple à une polarité négative, depuis une tension +VE1 à une tension -VE1.In the maintenance phase T3, the voltages VY and VE have opposite polarities. Thus, for example, in FIG. 3b at time t0, a maintenance window CEe begins which is applied to the maintenance only electrodes E1 to E4, and the transition of which represents a voltage variation Δ VE which in example s 'performs substantially symmetrically with respect to the reference voltage VR; this first maintenance interval CEe applied to the maintenance only electrodes E1 to E4 passing for example to a negative polarity, from a voltage + VE1 to a voltage -VE1.
Dans le même temps, à l'instant t0, débute un créneau d'entretien CEY appliqué aux électrodes d'adressage-entretien Y1 à Y4, ce créneau d'entretien CEY ayant une polarité positive, c'est-à-dire opposée à celle qui dans le même temps est appliquée aux électrodes uniquement d'entretien E1 à E4, la transition ayant été effectuée à l'instant t0 depuis une tension négative -VY1 jusqu'à une tension positive +VY1 ; dans l'exemple non limitatif décrit, cette transition représente une variation de tension Δ VY1 qui est effectuée d'une manière sensiblement symétrique par rapport à la tension de référence VR.At the same time, at time t0, begins a CEY maintenance slot applied to the addressing-maintenance electrodes Y1 to Y4, this CEY maintenance slot having a positive polarity, that is to say opposite to that which at the same time is applied to the electrodes only of maintenance E1 to E4, the transition having been carried out at time t0 from a negative voltage -VY1 to a positive voltage + VY1; in the nonlimiting example described, this transition represents a voltage variation Δ VY1 which is carried out in a manner substantially symmetrical with respect to the reference voltage VR.
En supposant qu'avant l'instant t0, le sixième pixel PX6 était à l'état inscrit : des charges (non représentées) étaient stockées sur le diélectrique des seconde électrodesY2, E2 de la seconde paire P2, au niveau du sixième pixel PX6, et les transitions à l'instant t0 des créneaux d'entretien CEY et CEe développent au niveau du sixième pixel PX6 un champ électrique dont l'effet s'ajoute à celui des charges déjà stockées pour provoquer une décharge d'entretien De1 (figure 3c) ; cette décharge d'entretien dure sensiblement jusqu'à un instant t1 où des charges de polarités contraires aux précédentes sont engendrées de manière en elle-même connue.Assuming that before time t0, the sixth pixel PX6 was in the written state: charges (not shown) were stored on the dielectric of the second electrodes Y2, E2 of the second pair P2, at the level of the sixth pixel PX6, and the transitions at time t0 of the CEY and CEe maintenance slots develop at the level of the sixth pixel PX6 an electric field whose effect is added to that of the charges already stored to cause a maintenance discharge De1 (Figure 3c); this maintenance discharge lasts substantially up to an instant t1 where charges of polarities contrary to the preceding ones are generated in a manner known per se.
Les créneaux d'entretien CEY et CEe appliqués respectivement à toutes les électrodes d'adressage-entretien Y1 à Y4 et toutes les électrodes d'entretien E1 à E4 sont maintenus jusqu'à un instant t2. A cet instant t2, les polarités des tensions VY et VE s'inversent et restent opposées jusqu'à un instant t4 qui marque le début de la phase d'effacement T1. On note qu'à l'instant t2 la transition des créneaux d'entretien CEY et CEe provoque une nouvelle décharge d'entretien De2 au niveau du sixième pixel PX6 ; comme pour la décharge d'entretien précédente, cette décharge prend fin à un instant t3 où des charges accumulées sur les électrodes d'entretien YE, E2, avec une polarité opposée à celle qu'elles avaient à l'instant t2, sont en quantité suffisante pour provoquer l'extinction.The maintenance slots CEY and CEe applied respectively to all the addressing-maintenance electrodes Y1 to Y4 and all the maintenance electrodes E1 to E4 are maintained until an instant t2. At this instant t2, the polarities of the voltages VY and VE are reversed and remain opposite until an instant t4 which marks the start of the erasure phase T1. It is noted that at time t2 the transition of the maintenance slots CEY and CEe causes a new maintenance discharge De2 at the level of the sixth pixel PX6; as for the previous maintenance discharge, this discharge ends at an instant t3 where charges accumulated on the maintenance electrodes YE, E2, with a polarity opposite to that which they had at the instant t2, are in quantity sufficient to cause extinction.
A l'instant t4 où débute la phase d'effacement T1, les polarités des tensions VE et VY appliquées respectivement aux électrodes d'entretien E1 à E4 et aux électrodes d'adressage-entretien Y1 à Y4 s'inversent à nouveau et restent opposées. On remarque que les créneaux appliqués aux électrodes uniquement d'entretien E1 à E4 ont toujours une même amplitude Δ VE, c'est-à-dire que seulement 2 niveaux de tension (+VE1 et -VE1) sont nécessaires à commander ces électrodes d'entretien E1 à E4.At the instant t4 when the erasing phase T1 begins, the polarities of the voltages VE and VY applied respectively to the maintenance electrodes E1 to E4 and to the address-maintenance electrodes Y1 to Y4 reverse again and remain opposite . Note that the slots applied to the electrodes only for maintenance E1 to E4 always have the same amplitude Δ VE, that is to say that only 2 voltage levels (+ VE1 and -VE1) are necessary to control these electrodes d interview E1 to E4.
A l'instant t4, la tension VE est formée par un créneau de tension de polarité positive qui est appliqué aux électrodes uniquement d'entretien E1 à E4, alors que dans le même temps, un créneau CBe de polarité opposée, c'est-à-dire négative, est appliqué aux électrodes d'adressage-entretien Y1 à Y4 ; mais ce créneau Cbe atteint une valeur VY2 inférieure à la valeur VY1, et il conserve cette valeur VY2 jusqu'à un instant t7 où la polarité de la tension VY s'inverse à nouveau.At time t4, the voltage VE is formed by a voltage slot of positive polarity which is applied to the maintenance only electrodes E1 to E4, while at the same time, a slot CBe of opposite polarity, that is to say ie negative, is applied to the addressing-maintenance electrodes Y1 to Y4; but this slot Cbe reaches a value VY2 lower than the value VY1, and it retains this value VY2 until an instant t7 when the polarity of the voltage VY reverses again.
Dans ces conditions, à l'instant t4, la transition du créneau CBe appliqué aux électrodes d'adressage-entretien Y1 à Y4 a une valeur Δ VY2 inférieure à la valeur ΔVY1 d'un créneau d'entretien CEY, de sorte que le potentiel développé entre les électrodes d'entretien Y1 à Y4 et E1 à E4 est insuffisant pour provoquer une décharge d'entretien, même quand il s'ajoute à l'effet de charges déjà stockées sur ces électrodes d'entretien. Les créneaux appliqués aux électrodes d'adressage-entretien Y1 à Y4 à l'instant t4, sont destinées à former une base ou marche de tension appelée créneau de base d'effacement CBe auquel on superpose, uniquement sur le créneau appliqué à l'électrode d'adressage-entretien de la paire P1 à P4 adressée (à savoir dans le cas présent uniquement le créneau appliqué à la seconde électrode d'adressage -entretien Y2), une impulsion de tension appelée impulsion d'effacement IE, IE'.Under these conditions, at time t4, the transition of the slot CBe applied to the addressing-maintenance electrodes Y1 to Y4 has a value Δ VY2 lower than the value ΔVY1 of a maintenance slot CEY, so that the potential developed between the maintenance electrodes Y1 to Y4 and E1 to E4 is insufficient to cause a maintenance discharge, even when it is added to the effect of charges already stored on these maintenance electrodes. The slots applied to the addressing-maintenance electrodes Y1 to Y4 at time t4, are intended to form a voltage base or step called the erasing base slot CBe which is superimposed, only on the slot applied to the electrode addressing-maintenance of the pair P1 to P4 addressed (namely in this case only the slot applied to the second addressing-maintenance electrode Y2), a voltage pulse called erase pulse IE, IE '.
L'impulsion d'effacement peut avoir la forme d'un créneau rectangulaire ayant soit une forte amplitude et une durée brève, soit une faible amplitude et une longue durée, ou encore être formée d'une impulsion dont le front de montée s'établit de manière relativement lente et constitue une rampe, comme il est expliqué dans la demande de brevet n° 78 04893 précédemment citée, déposée au nom de THOMSON-CSF et publiée sous le n° FR-A-2 417 848, et qui doit être considérée comme faisant partie de la présente description.The erasure pulse may have the form of a rectangular slot having either a high amplitude and a short duration, or a low amplitude and a long duration, or even be formed of a pulse whose rising edge is established relatively slowly and constitutes a ramp, as explained in the patent application No. 78 04893 cited above, filed in the name of THOMSON-CSF and published under No. FR-A-2 417 848, and which must be considered to be part of this description.
Dans l'exemple non limitatif décrit, l'impulsion d'effacement IE (représentée en tireté) qui est superposée au créneau de base d'effacement CBe, est une impulsion dont le front de montée R s'établit de façon relativement lente comme décrit dans le brevet ci-dessus cité, jusqu'à atteindre sensiblement la première valeur VY1 ; mais l'impulsion d'effacement pourrait être constituée aussi par une impulsion IE'(représentée en traits mixtes) de durée relativement brève, et qui serait superposée au créneau de base d'effacement CBE à partir par exemple de l'instant t4. Bien entendu, le créneau d'effacement IE, IE' n'est superposé à un créneau de base d'effacement CBe que pour la paire d'électrodes P1 à P4 adressée ; compte tenu de l'exemple décrit, c'est uniquement à la seconde électrode d'adressage Y2 qu'est appliqué un créneau de base d'effacement CBe auquel on superpose une impulsion d'effacement IE, IE'. En supposant que l'impulsion d'effacement soit celle dont le front de montée constitue une rampe R, la superposition de cette impulsion d'effacement IE avec le créneau de base CBe va provoquer sensiblement à l'instant t5 où la rampe R atteint sensiblement la première valeur VY1, une décharge d'effacement DEF entre la seconde électrode d'adressage-entretien Y2 et la seconde électrode uniquement d'entretien E2, au niveau de chaque pixel. Cette décharge d'effacement est d'intensité plus faible que les décharges d'entretien DE1, DE2, et cesse sensiblement à un instant t6 sans provoquer l'accumulation de charges comme dans le cas des décharges d'entretien DE1, DE2. Dans cette configuration, tous les pixels PX5 à PX8 de la seconde paire P2 sont effacés.In the nonlimiting example described, the erasing pulse IE (shown in dashed lines) which is superimposed on the erasing base slot CBe, is a pulse whose rising edge R is established relatively slowly as described in the aforementioned patent, until substantially reaching the first value VY1; but the erasing pulse could also be constituted by an IE ′ pulse (shown in dashed lines) of relatively short duration, and which would be superimposed on the erasing basic slot CBE from for example from time t4. Of course, the niche erasing IE, IE 'is superimposed on a basic erasing slot CBe only for the pair of electrodes P1 to P4 addressed; taking into account the example described, it is only to the second addressing electrode Y2 that an erasing base slot CBe is applied to which an erasing pulse IE, IE ′ is superimposed. Assuming that the erase pulse is the one whose rising edge constitutes a ramp R, the superposition of this erase pulse IE with the basic slot CBe will cause substantially at time t5 when the ramp R reaches substantially the first value VY1, an erasure discharge DEF between the second addressing-maintenance electrode Y2 and the second solely maintenance electrode E2, at the level of each pixel. This erasure discharge is of lower intensity than the maintenance discharges DE1, DE2, and substantially ceases at an instant t6 without causing the accumulation of charges as in the case of the maintenance discharges DE1, DE2. In this configuration, all the pixels PX5 to PX8 of the second pair P2 are erased.
Ainsi on note qu'une caractéristique importante du procédé de l'invention consiste à engendrer une décharge d'effacement uniquement entre les deux électrodes d'entretien Y2, E2 d'une même paire P2 donnée, cette décharge d'effacement DEF ayant pour effet d'effacer tous les pixels qui correspondent à cette paire P2 d'électrodes.Thus, it is noted that an important characteristic of the process of the invention consists in generating an erasure discharge only between the two maintenance electrodes Y2, E2 of the same given pair P2, this erasure discharge DEF having the effect to erase all the pixels which correspond to this pair P2 of electrodes.
Il est à noter que pour les lignes de pixels L1, L3, L4 ou paires P1, P3 et P4 d'électrodes dont l'électrode d'adressage-entretien Y1, Y3, Y4 ne reçoit pas d'impulsion d'effacement IE, IE', la présence du créneau de base d'effacement CBe n'a aucune incidence : tous les pixels qui sont effacés, restent effacés, et tous les pixels qui sont inscrits restent inscrits, c'est-à-dire que les charges qui existaient sur les deux électrodes d'une paire d'électrodes d'entretien, à l'instant t3 par exemple, subsistent jusqu'à un instant t8 qui marque le début de la phase T2 d'inscription et auquel peuvent se produire des décharges d'entretien au niveau des pixels inscrits.It should be noted that for the pixel lines L1, L3, L4 or pairs P1, P3 and P4 of electrodes of which the addressing-maintenance electrode Y1, Y3, Y4 does not receive an erase pulse IE, IE ', the presence of the basic erasing slot CBe has no effect: all the pixels which are erased remain erased, and all the pixels which are inscribed remain inscribed, that is to say that the charges which existed on the two electrodes of a pair of maintenance electrodes, at time t3 for example, subsist until time t8 which marks the start of the T2 registration phase and at which can maintenance discharges occur at the pixels recorded.
Selon une autre caractéristique de l'invention, après l'effacement de tous les pixels d'une paire P1 à P4 d'électrodes d'entretien donnée, la seconde paire P2 dans l'exemple, on réalise l'inscription des pixels désirés appartenant à cette paire P2 d'électrodes, en provoquant une décharge d'inscription entre la seconde électrode d'adressage-entretien Y2 et chacune des électrodes colonnes X1 à X4 dont l'intersection avec la seconde électrode d'adressage-entretien Y2 représente un pixel que l'on veut inscrire. Ainsi dans le cas qui a été prévu, à savoir l'inscription du septième pixel PX7, on réalise une décharge d'inscription uniquement entre la seconde électrode d'adressage-entretien Y2 et la troisième électrode colonne X3. Ceci est effectué durant la phase d'inscription T2 qui commence à l'instant t8.According to another characteristic of the invention, after the erasure of all the pixels of a pair P1 to P4 of given maintenance electrodes, the second pair P2 in the example, the desired pixels belonging to the registration are carried out to this pair P2 of electrodes, by causing a writing discharge between the second addressing-maintenance electrode Y2 and each of the column electrodes X1 to X4 whose intersection with the second addressing-maintenance electrode Y2 represents a pixel that we want to register. Thus in the case which has been provided, namely the writing of the seventh pixel PX7, a writing discharge is carried out only between the second addressing-maintenance electrode Y2 and the third column electrode X3. This is done during the registration phase T2 which begins at time t8.
On remarque qu'à l'instant t7, qui correspond à la fin du créneau de base d'effacement CBe, les polarités des tensions VY, VE appliquées respectivement aux électrodes d'adressage-entretien Y1 à Y4 ET E1 à E4 s'inversent : la polarité de la tension VE devient positive et le reste jusqu'à l'instant t8, et la polarité de la tension VY devient négative et le reste jusqu'à l'instant t8. L'intervalle de temps Δ t1 entre l'instant t7 et l'instant t8 permet éventuellement de stabiliser l'effacement qui a été réalisé. Cette stabilisation dépend de caractéristiques particulières au panneau à plasma utilisé, de sorte que l'intervalle de temps Δ t1 peut éventuellement être réduit ou même supprimé, ce qui permet de réduire la durée de la période T (qui représente le cycle de base). Ce cycle de base peut avoir une durée encore plus faible, telle que représentée par exemple par la durée T', en supprimant les créneaux qui appartiennent à la phase d'entretien T3 ; ceci est rendu possible par le fait que même en supprimant la phase d'entretien T3, on peut avec le procédé de commande conforme à l'invention obtenir des décharges d'entretien par la phase d'inscription T2.It is noted that at the instant t7, which corresponds to the end of the basic erasing slot CBe, the polarities of the voltages VY, VE applied respectively to the address-maintenance electrodes Y1 to Y4 AND E1 to E4 are reversed : the polarity of the voltage VE becomes positive and remains so until time t8, and the polarity of the voltage VY becomes negative and remains so until time t8. The time interval Δ t1 between instant t7 and instant t8 optionally makes it possible to stabilize the erasure that has been carried out. This stabilization depends on characteristics specific to the plasma panel used, so that the time interval Δ t1 can possibly be reduced or even eliminated, which makes it possible to reduce the duration of the period T (which represents the basic cycle). This basic cycle can have an even shorter duration, as represented for example by the duration T ′, by eliminating the slots which belong to the maintenance phase T3; this is made possible by the fact that even by eliminating the maintenance phase T3, it is possible with the method of control in accordance with the invention obtain maintenance discharges by the T2 registration phase.
A l'instant t8 : la tension VE devient négative ; la tension VY devient positive par un créneau de tension CBi appliqué aux électrodes d'adressage-entretien Y1 à Y4 ; la tension VY passe alors à la valeur VY1, soit une variation Δ VY1 par laquelle il est possible d'obtenir des décharges d'entretien pour tous les pixels inscrits. Ainsi par exemple si l'on n' avait pas effacé le sixième pixel P6 (en même temps que les autres pixels de la seconde ligne L2), on aurait conservé des charges sur les électrodes Y2 et E2 qui auraient permis de produire une décharge d'entretien De3 (représentée en traits pointillés) à l'instant t8.At time t8: the voltage VE becomes negative; the voltage VY becomes positive by a voltage pulse CBi applied to the addressing-maintenance electrodes Y1 to Y4; the voltage VY then passes to the value VY1, that is to say a variation Δ VY1 by which it is possible to obtain maintenance discharges for all the pixels entered. So for example if we had not erased the sixth pixel P6 (at the same time as the other pixels of the second line L2), we would have kept charges on the electrodes Y2 and E2 which would have allowed to produce a discharge of 'interview De3 (shown in dotted lines) at time t8.
Pour inscrire le ou les pixels d'une ligne ou paire donnée d'électrodes, on superpose un créneau d'inscription CI, au créneau de tension CBi qui, entre l'instant t8 et un instant t12, est appliqué à toutes les électrodes d'adressage-entretien. Bien entendu, un créneau d'inscription CI n'est superposé qu'au créneau de base d'inscription CBi qui est appliqué à l'adresse voulue, c'est-à-dire à l'électrode d'adressage-entretien de la paire d'électrodes considérée, à savoir dans l'exemple la seconde électrode d'adressage-entretien Y2 de la seconde paire 2. Le créneau de tension CBi constitue ainsi un créneau de base d'inscription formant une marche de tension à laquelle s'ajoute la tension du créneau d'inscription CI ; mais il constitue aussi un créneau d'entretien pour les paires P1, P3, P4 des autres électrodes d'adressage-entretien Y1, Y3, Y4, non adressées.To register the pixel or pixels of a given line or pair of electrodes, a registration window CI is superimposed on the voltage window CBi which, between time t8 and time t12, is applied to all the electrodes d addressing-interview. Of course, a registration slot CI is only superimposed on the basic registration slot CBi which is applied to the desired address, that is to say to the address-maintenance electrode of the pair of electrodes in question, namely in the example the second addressing-maintenance electrode Y2 of the
Le créneau d'inscription CI superposé au créneau de base d'inscription CBI atteint une valeur de tension VY3 telle, que la différence de potentiel qui est alors engendrée entre les électrodes colonnes X1 à X4 et la seconde électrode d'adressage-entretien Y2 peut provoquer une décharge, appelée décharge d'inscription, au croisement entre cette dernière et les électrodes colonnes X1 à X4. Aussi, on inscrit uniquement le ou les pixels désirés en appliquant sur les électrodes colonnes X1 à X4 qui correspondent aux pixels qui ne doivent pas être inscrits, une impulsion de tension dite impulsion de masquage MX1 à MX4, de même polarité que le créneau d'inscription CI ; de sorte que le potentiel nécessaire à produire une décharge entre une électrode colonne X1 à X4 et l'électrode Y2, est atteint uniquement avec l'électrode colonne à laquelle on n'applique pas d'impulsion dite de masquage. Bien entendu si une impulsion de masquage est appliquée sur toutes les électrodes colonnes X1 à X4 aucun des pixels n'est inscrit. Dans l'exemple non limitatif décrit, et comme illustré aux figures 3d, 3e, 3f, 3g, les électrodes colonnes X1 à X4 sont portées au potentiel de la tension de référence VR, sauf pendant la phase d'inscription T2 où une impulsion de masquage peut leur être appliquée, qui porte leur tension à une valeur VX.The registration window CI superimposed on the basic registration window CBI reaches a voltage value VY3 such that the potential difference which is then generated between the column electrodes X1 to X4 and the second addressing-maintenance electrode Y2 can cause a discharge, called registration discharge, at the intersection between the latter and the column electrodes X1 to X4. Also, we only enter the or the desired pixels by applying to the column electrodes X1 to X4 which correspond to the pixels which must not be written, a voltage pulse called the masking pulse MX1 to MX4, of the same polarity as the writing slot CI; so that the potential necessary to produce a discharge between a column electrode X1 to X4 and the electrode Y2, is reached only with the column electrode to which a so-called masking pulse is not applied. Of course, if a masking pulse is applied to all of the column electrodes X1 to X4, none of the pixels are registered. In the nonlimiting example described, and as illustrated in FIGS. 3d, 3e, 3f, 3g, the column electrodes X1 to X4 are brought to the potential of the reference voltage VR, except during the writing phase T2 where a pulse of masking can be applied to them, which brings their voltage to a VX value.
Dans l'exemple décrit, où c'est le septième pixel PX7 que l'on cherche à inscrire, on applique une impulsion de masquage MX1, MX2, MX4, sur la première, la seconde et la quatrième électrode colonne X1, X2, X4, pendant au moins et on n'applique pas d'impulsion de masquage sur la troisième électrode colonne X3. Il en résulte sensiblement à un instant t10 une décharge d'inscription DI (illustrée à la figure 3h) entre la seconde électrode adressage-entretien Y2 et la troisième électrode colonne X3, au croisement de ces derniers, c'est-à-dire au niveau du septième pixel PX7. La fin du créneau d'inscription CI intervient sensiblement en même temps que la fin du créneau de base d'inscription CBi, à un instant t11 qui par exemple précède faiblement l'instant t12 de fin du créneau de base d'inscription CBi.In the example described, where it is the seventh pixel PX7 that one seeks to register, a masking pulse MX1, MX2, MX4 is applied to the first, the second and the fourth column electrode X1, X2, X4 , for at least and a masking pulse is not applied to the third column electrode X3. This results substantially at a time t10 in a registration discharge DI (illustrated in FIG. 3h) between the second addressing-maintenance electrode Y2 and the third column electrode X3, at the crossing of the latter, that is to say at the level of the seventh pixel PX7. The end of the registration slot CI occurs substantially at the same time as the end of the registration base slot CBi, at a time t11 which for example slightly precedes the time t12 at the end of the registration base slot CBi.
Il est à noter que pour éviter une décharge indésirable entre la seconde électrode d'adressage-entretien Y2 et la seconde électrode d'entretien E2, on diminue la différence de potentiel entre ces deux électrodes en inversant la polarité de la tension VE appliquée aux électrodes E1 à E4 avant que ne soit effectuée la superposition du créneau d'inscription CI sur le créneau de base d'inscription CBi : à partir de l'instant t8, la tension VE passe de positif à négatif et constitue un créneau CNE de polarité négative ; puis la polarité de la tension VE (appliquée aux électrodes uniquement d'entretien E1 à E4) est à nouveau inversée à un instant t9 et comporte une polarité positive, ceci sensiblement en même temps ou un peu avant que ne débute le créneau d'inscription Ci, ou en tout cas avant un instant t10 où le créneau d'inscription CI atteint la valeur VY3 ; la tension VE comporte alors une même polarité que la tension VY appliquée aux électrodes d'adressage-entretien et, entre la seconde électrode d'entretien E2 et la seconde électrode d'adressage-entretien Y2 existe alors une différence de potentiel insuffisante pour provoquer une décharge parasite lors de la superposition du créneau d'inscription CI.It should be noted that to avoid an undesirable discharge between the second addressing-maintenance electrode Y2 and the second maintenance electrode E2, the potential difference between these two electrodes is reduced by reversing the polarity of the voltage VE applied to the electrodes E1 to E4 before the CI registration window is superimposed on the basic registration window CBi: from time t8, the voltage VE goes from positive to negative and constitutes a window CNE of negative polarity; then the polarity of the voltage VE (applied to the maintenance only electrodes E1 to E4) is again inverted at an instant t9 and comprises a positive polarity, this substantially at the same time or a little before the registration window begins. Ci, or in any case before an instant t10 when the CI registration window reaches the value VY3; the voltage VE then has the same polarity as the voltage VY applied to the address-maintenance electrodes and, between the second maintenance electrode E2 and the second address-maintenance electrode Y2, then there is an insufficient potential difference to cause a parasitic discharge during the superimposition of the CI registration window.
Il est à noter qu'un avantage apporté par cet agencement réside dans le fait que, les impulsions de masquage MX1 à MX4 sont produites avec une puissance relativement faible (du fait que c'est avec les décharges d'entretien que l'on cherche à produire la lumière émise par les pixels, et avec une amplitude en tension relativement faible), de sorte que des composants standards et à faible prix peuvent être utilisés pour la commande des électrodes colonnes X1 à X4. On note en outre qu'un autre avantage important apporté par le procédé conforme à l'invention, réside en ce que la décharge qui est créée se produit uniquement pour les points à inscrire et non pas pour tous les points de la ligne, ce qui tend à augmenter de manière considérable la longévité des luminophores qui sont utilisés pour l'émission de lumière en couleur.It should be noted that an advantage brought by this arrangement resides in the fact that, the masking pulses MX1 to MX4 are produced with a relatively low power (because it is with the maintenance discharges that one seeks to produce the light emitted by the pixels, and with a relatively low voltage amplitude), so that standard and low-cost components can be used for controlling the column electrodes X1 to X4. It is further noted that another important advantage provided by the method according to the invention, resides in that the discharge which is created occurs only for the points to be entered and not for all the points of the line, which tends to significantly increase the longevity of the phosphors which are used for the emission of color light.
On indique ci-après à titre uniquement d'exemple non limitatif, des valeurs de tension qui peuvent être appliquées pour la mise en oeuvre du procédé de l'invention, avec un panneau à plasma de type classique :
- les variations Δ VE de la tension VE peuvent être de l'ordre de 100 volts ;
- pour la tension VY, les variations Δ VY1 peuvent être de l'ordre de 150 volts, les variations Δ VY2 peuvent être de l'ordre de 80 volts ;
- les impulsions de masquage appliquées aux électrodes colonnes X peuvent avoir une amplitude de l'ordre de 40 volts ;
- les créneaux d'inscription Ci peuvent avoir une amplitude de l'ordre de 80 volts. Bien entendu ces valeurs sont données uniquement à titre d'exemple et peuvent être aisément modifiées en fonction des caractéristiques du panneau à plasma utilisé.
- the variations Δ VE of the voltage VE can be of the order of 100 volts;
- for the voltage VY, the variations Δ VY1 can be of the order of 150 volts, the variations Δ VY2 can be of the order of 80 volts;
- the masking pulses applied to the column X electrodes can have an amplitude of the order of 40 volts;
- the registration slots Ci can have an amplitude of the order of 80 volts. Of course these values are given only by way of example and can be easily modified as a function of the characteristics of the plasma panel used.
A l'instant t12, la fin du créneau de base d'inscription CBi correspond à la fin de la phase d'inscription T2, et correspond à une inversion de la polarité de la tension VY appliquée aux électrodes d'adressage-entretien Y1 à Y4, polarité qui dévient négative. La tension VE appliquée aux électrodes d'entretien E1 à E4 est positive depuis sensiblement l'instant t9 et, dans l'exemple non limitatif décrit, elle conserve cette polarité positive jusqu'à un instant t0' qui marque le début d'un nouveau cycle. Il est à noter que la décharge d'inscription DI a engendré l'accumulation de charges négatives (non représentées) sur le diélectrique de la seconde électrode d'adressage-entretien Y2 au niveau du septième pixel PX7 : aussi à la transition de positif vers négatif de la tension VY, due à la fin du créneau d'inscription CI et du créneau de base d'inscription CBi s'ajoute l'effet de la présence des charges négatives accumulées sur l'électrode Y2 de sorte que, sensiblement quand la tension VY atteint la valeur -Vy1, il se produit une décharge de reprise d'entretien DRE (figure 3c) au niveau du septième pixel PX7, entre la seconde électrode d'adressage-entretien Y2 et la seconde électrode d'entretien E2. Par suite de cette reprise en décharge d'entretien, des charges peuvent être à nouveau accumulées à la fois sur les deux électrodes de la seconde paire P2.At time t12, the end of the basic registration window CBi corresponds to the end of the registration phase T2, and corresponds to an inversion of the polarity of the voltage VY applied to the addressing-maintenance electrodes Y1 to Y4, polarity which becomes negative. The voltage VE applied to the maintenance electrodes E1 to E4 has been positive since substantially the instant t9 and, in the nonlimiting example described, it retains this positive polarity until an instant t0 'which marks the start of a new cycle. It should be noted that the DI registration discharge generated the accumulation of negative charges (not shown) on the dielectric of the second addressing-maintenance electrode Y2 at the level of the seventh pixel PX7: also at the transition from positive to negative of the voltage VY, due to the end of the writing window CI and the basic writing window CBi, is added the effect of the presence of the negative charges accumulated on the electrode Y2 so that, appreciably when the voltage VY reaches the value -Vy1, there is a maintenance resumption discharge DRE (FIG. 3c) at the seventh pixel PX7, between the second addressing-maintenance electrode Y2 and the second maintenance electrode E2. As a result of this recovery in maintenance discharge, charges can be accumulated again at the same time on the two electrodes of the second pair P2.
Les tensions VY et VE conservent leur polarité respectivement négative et positive jusqu'à l'instant t0' où débute un nouveau cycle. Il est à noter que suivant les caractéristiques propres au panneau à plasma utilisé, il est possible qu'une décharge (représentée en traits pointillés à la figure 3h) se produise sensiblement à l'instant t12 entre l'électrode colonne X3 et l'électrode adressage-entretien Y2 ; dans un tel cas, une décharge de reprise d'entretien DRE' (montrée en traits pointillés à la figure 3c) se produit à l'instant t0' de début d'un nouveau cycle.The voltages VY and VE keep their negative and positive polarity respectively until time t0 'where begins a new cycle. It should be noted that, depending on the characteristics specific to the plasma panel used, it is possible that a discharge (shown in dotted lines in FIG. 3h) occurs substantially at time t12 between the column electrode X3 and the electrode addressing-interview Y2; in such a case, a maintenance resumption discharge DRE '(shown in dotted lines in FIG. 3c) occurs at the instant t0' of the start of a new cycle.
Il est à noter que le cycle de base est appliqué à toutes les électrodes d'entretien avec une fréquence qui dépend de la durée de la période T, T'. Compte-tenu de temps incompressibles, notamment les temps nécessaires à la commande de circuits annexes (non représentés), la durée d'une période T, T' peut difficilement descendre en dessous de 22 microsecondes ou 20 microsecondes. Ceci permet néanmoins d'obtenir des performances très intéressantes même avec un panneau à plasma comportant un grand nombre de lignes. En prenant pour exemple un panneau à plasma comportant 1 000 lignes, il faut 20 millisecondes pour explorer une image entière, c'est-à-dire qu'il est possible d'obtenir 50 images par seconde.It should be noted that the basic cycle is applied to all the maintenance electrodes with a frequency which depends on the duration of the period T, T '. Taking into account incompressible times, in particular the times necessary for the control of auxiliary circuits (not shown), the duration of a period T, T 'can hardly fall below 22 microseconds or 20 microseconds. This nevertheless makes it possible to obtain very interesting performances even with a plasma panel comprising a large number of lines. Taking for example a plasma panel comprising 1000 lines, it takes 20 milliseconds to explore an entire image, that is to say it is possible to obtain 50 images per second.
On indique ci-après, uniquement à titre d'exemple non limitatif des durées possibles des différents signaux représentés aux figures 3 :
-les créneaux d'entretien CEY et CEe ont une durée classique de l'ordre de quelques microsecondes ; le créneau de base d'effacement CBe peut avoir une durée de l'ordre de 5 microsecondes ; l'intervalle de temps Δ t1 peut être de l'ordre de 3 à 4 microsecondes. Le créneau de base d'inscription CBi peut avoir une durée de l'ordre de 7 microsecondes ; et le créneau d'inscription Ci qui lui est superposé peut avoir une durée d'environ 4 microsecondes, et/ou éventuellement avoir une même forme que l'impulsion d'effacement IE dont le front de montée constitue une rampe R, et dont la durée au sommet peut être de l'ordre de zéro à quelques microsecondes ; le créneau négatif repéré CNE sur la tension VE peut avoir une durée de l'ordre de 3 microsecondes.It is indicated below, solely by way of nonlimiting example of the possible durations of the various signals represented in FIGS.
the CEY and CEe maintenance slots have a conventional duration of the order of a few microseconds; the basic erasing slot CBe can have a duration of the order of 5 microseconds; the time interval Δ t1 can be of the order of 3 to 4 microseconds. The basic CBi registration slot can have a duration of the order of 7 microseconds; and the registration window Ci which is superimposed on it may have a duration of approximately 4 microseconds, and / or possibly have the same shape as the erasure pulse IE whose rising edge constitutes a ramp R, and whose duration at the top can be of the order of zero to a few microseconds; the niche negative marked CNE on the voltage VE can have a duration of the order of 3 microseconds.
Sur la tension VE, on observe que le créneau négatif CNE est suivi d'un créneau positif (à partir de l'instant t9), ce créneau positif étant constitué, pour sa partie formée entre la fin du créneau négatif CNE et l'instant t12 de fin du créneau de base d'inscription, par un créneau de masquage CME qui remplit une fonction d'inhibition du créneau d'inscription CI vis-à-vis de la seconde électrode uniquement d'entretien E2, en vue d'éviter une décharge parasite entre cette seconde électrode E2 et la seconde électrode d'adressage-entretien Y2.On the voltage VE, it is observed that the negative slot CNE is followed by a positive slot (from time t9), this positive slot being formed, for its part formed between the end of the negative slot CNE and the time t12 at the end of the basic registration window, by a CME masking window which fulfills a function of inhibiting the registration window CI vis-à-vis the second maintenance-only electrode E2, in order to avoid a parasitic discharge between this second electrode E2 and the second addressing-maintenance electrode Y2.
Il est à remarquer que les variations des tensions VY et VE appliquées respectivement aux électrodes d'adressage-entretien Y1 à Y4 et aux électrodes dites uniquement d'entretien E1 à E4, Δ VE et Δ VY1 par exemple, sont d'amplitudes différentes contrairement à ce qui se pratique généralement dans l'art antérieur. Mais bien entendu ces variations de tensions peuvent être adaptées pour avoir des amplitudes semblables. Cependant il est intéressant avec le procédé de commande selon l'invention, d'avoir une dissymétrie entre les valeurs des créneaux de tensions appliqués d'une part aux électrodes d'adressage-entretien Y1 à Y4, et d'autre part aux électrodes dites uniquement d'entretien E1 à E4, pour plus facilement engendrer une décharge d'inscription qui génère suffisamment de charges pour faciliter la reprise en décharges d'entretien entre l'électrode d'adressage-entretien Y1 à Y4 intéressée et l'électrode dite uniquement d'entretien E1 à E4 correspondante, sans devoir apporter de charges sur cette électrode E1 à E4.It should be noted that the variations in the voltages VY and VE applied respectively to the addressing-maintenance electrodes Y1 to Y4 and to the so-called maintenance-only electrodes E1 to E4, Δ VE and Δ VY1 for example, are of different amplitudes, unlike to what is generally practiced in the prior art. But of course these voltage variations can be adapted to have similar amplitudes. However, it is advantageous with the control method according to the invention, to have an asymmetry between the values of the voltage slots applied on the one hand to the addressing-maintenance electrodes Y1 to Y4, and on the other hand to the so-called electrodes only maintenance E1 to E4, to more easily generate a registration discharge which generates enough charges to facilitate the resumption in maintenance discharges between the addressing-maintenance electrode Y1 to Y4 concerned and the so-called electrode only maintenance E1 to E4 corresponding, without having to bring charges on this electrode E1 to E4.
Claims (9)
- Method of line by line control of an AC type plasma panel with coplanar holding, the said panel comprising panel electrodes (X1 to X4) intersecting with two families of parallel holding electrodes (Y1 to Y4, E1 to E4), the first family of electrodes (Y1 to Y4) consisting of addressing/holding electrodes and the second family consisting of so-called holding only electrodes (E1 to E4), each addressing/holding electrode (Y1 to Y4) forming with an adjoining holding only electrode (E1 to E4) a holding electrode pair (P1 to P4), each pair of holding electrodes (P1 to P4) corresponding to a line of pixels (L1 to L4) perpendicular to the column electrodes (X1 to X4), the pixels (PX1 to PX16) being formed substantially at each intersection of a column electrode (X1 to X4) with a pair of holding electrodes (P1 to P4), the said method consisting in applying a first set of cyclic pulses to all the addressing/holding electrodes (Y1 to Y4) and a second set of cyclic pulses to all the so-called holding only electrodes (E1 to E4), the two sets of pulses having a same period (T, T') during which the said pulses develop between the two electrodes of each pair (PE1 to PE4) of holding electrodes voltages which constitute an erasure phase (T1) and a registering phase (T2) occurring after the erasure phase, the said voltages furthermore giving rise to holding discharges (DE1, DE2, DE3), the said method consisting in erasing a given complete line (L1 to L4) of pixels during the erasure phase (T1) by engendering erasure discharges (DEF) only between the addressing/holding electrode (Y1 to Y4) and the so-called holding only electrode (E1 to E4) of the corresponding pair (P1 to P4) of holding electrodes.
- Method of control according to Claim 1, consisting in engendering the holding discharges (DE1, DE2, DE3) by applying to all the addressing/holding electrodes (Y1 to Y4) at least one gating signal (CEY, CBI) having a first polarity and by applying to all the so-called holding only electrodes (E1 to E4) at least one second gating signal having a second polarity opposite to the first, the said first and second gating signals having a first and a second amplitude (ΔVY1, ΔVE) respectively, characterised in that, during the erasure phase (T1) it consists in applying to all the addressing/holding electrodes (Y1 to Y4) an erasure base gating signal (CBe) having a third amplitude (ΔVY2) less than the first amplitude (ΔVY1), and in applying in the same time (t4, t6) to all the so-called holding only electrodes (E1 to E4) a gating signal similar to the second gating signal and having a polarity opposite to that of the said erasure base gating signal (CBe), and in that an erasure pulse (IE, IE') is superimposed only on the erasure base gating signal (CBe) which is applied to the addressing/holding electrode (Y1 to Y4) corresponding to the said given line (L1 to L4) of pixels.
- Method of control according to Claim 2, characterised in that the erasure pulse (IE) is formed of a pulse whose rising edge constitutes a ramp (R).
- Method of control according to one of the preceding claims, characterised in that, for the registering of at least one pixel (PX1 to PX16) of a given line (L1 to L4) whose pixels have previously been erased, it consists in applying to all the addressing/holding electrodes (Y1 to Y4) a registering base gating signal (CBi) having the first polarity and having substantially the first amplitude (ΔVY1), and in superimposing a registering gating signal (CI) having the same first polarity only on the registering base gating signal (CBI) which is applied to the addressing/holding electrode (Y1 to Y4) corresponding to the said given line (L1 to L4), and substantially in the same time (T7, T9) as that in which the registering gating signal (CI) is superimposed, in applying voltage pulses (IMX) having the same first polarity to all the column electrodes (X1 to X4) with the exception of those which serve to define a pixel (PX1 to PX16) to be registered, and in that it furthermore consists substantially during the time (t7, t9) in which the registering gating signal (CI) is superimposed, in applying to all the so-called holding only electrodes (E1 to E4) a voltage gating signal having the said first polarity and constituting a second masking pulse (CME).
- Method of control according to Claim 4, characterised in that substantially at the instant (t8) at which the registering base gating signal (CBi) begins, a gating signal (CNE) having the said second polarity is applied to all the so-called holding only electrodes (E1 to E4) so as to give rise to holding discharges for the non-erased pixels (PX1 to PX16).
- Method of control according to Claim 5, characterised in that the said gating signal (CNE) having the second polarity ends before or substantially at the same instant (t9) as the instant (t10) at which the erasure pulse (IE, IE') begins.
- Method of control according to one of Claims 4 or 5 or 6, characterised in that it consists in applying to all the so-called holding only electrodes (E1 to E4) a voltage (VE) having the first polarity at the instant (t12) at which the registering base gating signal (CBi) finishes and at which the voltage (VY) applied to all the addressing/holding electrodes (Y1 to Y4) reverses in order to reach the second polarity, so as to give rise to a pick-up discharge (DRE) between the two electrodes (Y2, E2) of the relevant pair (P1 to P4) of electrodes at the level of each of the pixels (PX1 to PX16) having just been registered.
- Method of control according to one of the preceding claims, characterised in that the pulses (CEe, CNE, CME) applied to the holding only electrodes (E1 to E4) have an amplitude ( VE) less than the amplitude ( VY1, VY2) of the pulses (CEY, CBe, CBi) applied to the addressing/holding electrodes (Y1 to Y4).
- Method of control according to one of the preceding claims, characterised in that the pulses (CNE, CEe) applied to the holding only electrodes (E1 to E4) always have a same amplitude.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR8811247A FR2635901B1 (en) | 1988-08-26 | 1988-08-26 | METHOD OF LINE BY LINE CONTROL OF A PLASMA PANEL OF THE ALTERNATIVE TYPE WITH COPLANAR MAINTENANCE |
FR8811247 | 1988-08-26 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0357485A1 EP0357485A1 (en) | 1990-03-07 |
EP0357485B1 true EP0357485B1 (en) | 1993-07-14 |
Family
ID=9369531
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP89402281A Expired - Lifetime EP0357485B1 (en) | 1988-08-26 | 1989-08-11 | Method for the line-per-line control of an alternating-type plasma panel with a coplanar support |
Country Status (4)
Country | Link |
---|---|
US (1) | US5075597A (en) |
EP (1) | EP0357485B1 (en) |
DE (1) | DE68907538T2 (en) |
FR (1) | FR2635901B1 (en) |
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FR2662292B1 (en) * | 1990-05-15 | 1992-07-24 | Thomson Tubes Electroniques | METHOD FOR ADJUSTING THE BRIGHTNESS OF VISUALIZATION SCREENS. |
US6787995B1 (en) * | 1992-01-28 | 2004-09-07 | Fujitsu Limited | Full color surface discharge type plasma display device |
US7068264B2 (en) * | 1993-11-19 | 2006-06-27 | Hitachi, Ltd. | Flat display panel having internal power supply circuit for reducing power consumption |
US6522314B1 (en) | 1993-11-19 | 2003-02-18 | Fujitsu Limited | Flat display panel having internal power supply circuit for reducing power consumption |
FR2713382B1 (en) | 1993-12-03 | 1995-12-29 | Thomson Tubes Electroniques | Method for adjusting the overall brightness of a bistable matrix screen displaying halftones. |
JP3443167B2 (en) * | 1994-02-23 | 2003-09-02 | パイオニア株式会社 | Plasma display panel |
FR2741468B1 (en) * | 1995-11-17 | 1997-12-12 | Thomson Tubes Electroniques | METHOD FOR CONTROLLING A VISUALIZATION SCREEN AND VISUALIZATION DEVICE IMPLEMENTING SAID METHOD |
FR2744275B1 (en) * | 1996-01-30 | 1998-03-06 | Thomson Csf | METHOD FOR CONTROLLING A VIEWING PANEL AND VIEWING DEVICE USING THE SAME |
JP3565650B2 (en) * | 1996-04-03 | 2004-09-15 | 富士通株式会社 | Driving method and display device for AC type PDP |
FR2758204B1 (en) | 1997-01-07 | 1999-04-09 | Thomson Tubes Electroniques | METHOD FOR CONTROLLING THE ADDRESSING OF AN ALTERNATIVE PLASMA PANEL |
JP3573968B2 (en) * | 1997-07-15 | 2004-10-06 | 富士通株式会社 | Driving method and driving device for plasma display |
JP3697338B2 (en) | 1997-09-30 | 2005-09-21 | 松下電器産業株式会社 | Driving method of AC type plasma display panel |
FR2769115B1 (en) * | 1997-09-30 | 1999-12-03 | Thomson Tubes Electroniques | CONTROL PROCESS OF AN ALTERNATIVE DISPLAY PANEL INTEGRATING IONIZATION |
FR2773907B1 (en) * | 1998-01-20 | 2000-04-07 | Thomson Tubes Electroniques | BI-SUBSTRATE PLASMA PANEL WITH IMPROVED LIGHT OUTPUT |
JP3424587B2 (en) * | 1998-06-18 | 2003-07-07 | 富士通株式会社 | Driving method of plasma display panel |
US6507327B1 (en) * | 1999-01-22 | 2003-01-14 | Sarnoff Corporation | Continuous illumination plasma display panel |
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US6762566B1 (en) | 2000-10-27 | 2004-07-13 | Science Applications International Corporation | Micro-component for use in a light-emitting panel |
US6935913B2 (en) | 2000-10-27 | 2005-08-30 | Science Applications International Corporation | Method for on-line testing of a light emitting panel |
US6545422B1 (en) | 2000-10-27 | 2003-04-08 | Science Applications International Corporation | Socket for use with a micro-component in a light-emitting panel |
US6764367B2 (en) | 2000-10-27 | 2004-07-20 | Science Applications International Corporation | Liquid manufacturing processes for panel layer fabrication |
US7288014B1 (en) | 2000-10-27 | 2007-10-30 | Science Applications International Corporation | Design, fabrication, testing, and conditioning of micro-components for use in a light-emitting panel |
US6612889B1 (en) | 2000-10-27 | 2003-09-02 | Science Applications International Corporation | Method for making a light-emitting panel |
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US6796867B2 (en) | 2000-10-27 | 2004-09-28 | Science Applications International Corporation | Use of printing and other technology for micro-component placement |
US6570335B1 (en) | 2000-10-27 | 2003-05-27 | Science Applications International Corporation | Method and system for energizing a micro-component in a light-emitting panel |
US6801001B2 (en) | 2000-10-27 | 2004-10-05 | Science Applications International Corporation | Method and apparatus for addressing micro-components in a plasma display panel |
US6620012B1 (en) | 2000-10-27 | 2003-09-16 | Science Applications International Corporation | Method for testing a light-emitting panel and the components therein |
US6919685B1 (en) | 2001-01-09 | 2005-07-19 | Imaging Systems Technology Inc | Microsphere |
US7157854B1 (en) | 2002-05-21 | 2007-01-02 | Imaging Systems Technology | Tubular PDP |
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EP1387341A1 (en) * | 2002-07-30 | 2004-02-04 | Deutsche Thomson Brandt | Method and apparatus for grayscale enhancement of a display device |
US7566889B1 (en) * | 2006-09-11 | 2009-07-28 | The United States Of America As Represented By The Secretary Of The Air Force | Reflective dynamic plasma steering apparatus for radiant electromagnetic energy |
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US4638218A (en) * | 1983-08-24 | 1987-01-20 | Fujitsu Limited | Gas discharge panel and method for driving the same |
DE3486401T2 (en) * | 1983-12-09 | 1996-01-04 | Fujitsu Ltd | Method for controlling a gas discharge display device. |
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US4683470A (en) * | 1985-03-05 | 1987-07-28 | International Business Machines Corporation | Video mode plasma panel display |
US4924218A (en) * | 1985-10-15 | 1990-05-08 | The Board Of Trustees Of The University Of Illinois | Independent sustain and address plasma display panel |
US4866349A (en) * | 1986-09-25 | 1989-09-12 | The Board Of Trustees Of The University Of Illinois | Power efficient sustain drivers and address drivers for plasma panel |
ATE96567T1 (en) * | 1986-11-04 | 1993-11-15 | Univ Illinois | PLASMA DISPLAY PANEL WITH INDEPENDENT CIRCUITS FOR DISCHARGE SWITCHING AND ADDRESSING. |
FR2611295B1 (en) * | 1987-02-20 | 1989-04-07 | Thomson Csf | PLASMA PANEL WITH FOUR ELECTRODES BY ELEMENTARY IMAGE POINT AND METHOD FOR CONTROLLING SUCH A PLASMA PANEL |
-
1988
- 1988-08-26 FR FR8811247A patent/FR2635901B1/en not_active Expired - Lifetime
-
1989
- 1989-08-11 DE DE89402281T patent/DE68907538T2/en not_active Expired - Fee Related
- 1989-08-11 EP EP89402281A patent/EP0357485B1/en not_active Expired - Lifetime
- 1989-08-22 US US07/396,683 patent/US5075597A/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
FR2635901A1 (en) | 1990-03-02 |
DE68907538T2 (en) | 1994-01-20 |
FR2635901B1 (en) | 1990-10-12 |
US5075597A (en) | 1991-12-24 |
EP0357485A1 (en) | 1990-03-07 |
DE68907538D1 (en) | 1993-08-19 |
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