EP0793213A1 - Ansteuerungsverfahren für einen Anzeigebildschirm nach dem Prinzip der Modulation der Lichtemissionszeit und Anzeigevorrichtung, die dieses Verfahren verwendet - Google Patents

Ansteuerungsverfahren für einen Anzeigebildschirm nach dem Prinzip der Modulation der Lichtemissionszeit und Anzeigevorrichtung, die dieses Verfahren verwendet Download PDF

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Publication number
EP0793213A1
EP0793213A1 EP97400390A EP97400390A EP0793213A1 EP 0793213 A1 EP0793213 A1 EP 0793213A1 EP 97400390 A EP97400390 A EP 97400390A EP 97400390 A EP97400390 A EP 97400390A EP 0793213 A1 EP0793213 A1 EP 0793213A1
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EP
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Prior art keywords
activation
cells
sequence
state
luminance
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP97400390A
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English (en)
French (fr)
Inventor
Philippe Thomson-CSF SCPI Zorzan
Eric Thomson-CSF SCPI Benoit
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Thales SA
Vantiva SA
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Thomson Multimedia SA
Thomson CSF SA
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Publication of EP0793213A1 publication Critical patent/EP0793213A1/de
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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
    • 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
    • G09G3/2007—Display of intermediate tones
    • G09G3/2018—Display of intermediate tones by time modulation using two or more time intervals
    • G09G3/2022—Display of intermediate tones by time modulation using two or more time intervals using sub-frames
    • G09G3/2029—Display of intermediate tones by time modulation using two or more time intervals using sub-frames the sub-frames having non-binary weights
    • 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
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0266—Reduction of sub-frame artefacts
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/02—Details of power systems and of start or stop of display operation
    • G09G2330/025—Reduction of instantaneous peaks of current
    • 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

Definitions

  • the present invention relates to a method for controlling an image display screen using the principle of modulating the duration of light emission to display halftone. It applies to screens whose elementary image points are constituted by cells operating with two stable states and having a memory effect.
  • the invention also relates to an image display device implementing the method.
  • memory effect is meant the effect which allows cells to keep one or the other of the two stable states, after the signal having commanded this state has disappeared.
  • PAP plasma panels
  • continuous memory type or of the so-called “alternative” type, or even for example of screens whose cells elementaries use a "peak effect" phenomenon to each produce an electron beam.
  • the electrodes are covered with a dielectric material, so that, not being in contact with the gas, electric charges accumulate on the dielectric with each discharge in the gas.
  • This memory effect is used by means of alternative signals called maintenance signals, applied to all cells to activate those which are in the "on” state, that is to say cause in these cells discharges say maintenance which produce the light, without modifying their "on” state or modifying the state of those which are in the "off” state.
  • Some alternative PAPs use only two crossed electrodes to define and control a cell, as described, for example, in the French patent published with No. 2,417,848.
  • the two crossed electrodes are used both for addressing (that is to say the setting to the "on” state or the setting to the "off” state of the cell), and the maintenance discharges.
  • PAPs of the "coplanar maintenance" type as known in particular from the European patent document EP-A-0 135 382.
  • each cell is defined at the intersection between a so-called “addressing" electrode "and a pair of parallel electrodes.
  • the maintenance discharges are carried out using the two parallel electrodes, and the addressing is carried out using one of these two electrodes and the addressing electrode.
  • the elementary cell of a PAP only knows two states: the "on” state or the "off” state. Since analog modulation of the amount of light emitted by a pixel, i.e. by a cell, is not possible, the production of halftones is accomplished by modulating the duration of light emission of the pixel in an image period, or in other words by modulating the time during which the cell is put in the "on" state within the image period.
  • Figure 1 shows schematically an alternative PAP. To simplify the description, the latter is of the type with two crossed electrodes to define a cell, as described in French patent 2,417,848 cited above.
  • the PAP comprises an array of electrodes Y1 to Y4 called “row electrodes”, crossed with a second array of electrodes called “column electrodes” X1 to X4. Each intersection of row and column electrodes corresponds to a cell C1 to C16. These cells are thus arranged in line L1 to L4 and in columns CL1 to CL4.
  • Each row electrode Y1 to Y4 is connected to an output circuit SY1 to SY4 of a line 1 control device, and each column electrode C1 to C4 is connected to an output circuit SX1 to SX4 of a column 2 control device .
  • Each output SY1 to SY4 of the line 1 control device delivers voltage slots which form the previously mentioned maintenance signals. These maintenance signals are thus applied simultaneously to all the line electrodes Y1 to Y4.
  • FIGS. 2a to 2d represent maintenance signals applied respectively to the line electrodes Y1 to Y4.
  • FIG. 2a shows in particular that the maintenance signals are formed of a succession of voltage slots, established on either side of a reference potential Vo which is often the ground potential. These slots vary between a negative potential V1 where they have a level, and a positive potential V2 where they have another level.
  • the reference potential Vo is applied to the column electrodes X1 to X4 in such a way that the application of the maintenance signals develops, between the cells C1 to C16, alternately positive and negative voltages, of 150 V for example, which generate discharges. in all PAP cells which are in the "on" state.
  • the cells are put into the “on” or “off” state by addressing operations which are managed by the image management device 3. They can consist, for example, of superimposing signals specific addressing on niche maintenance signals.
  • the line electrodes Y1 to Y4 are individualized, that is to say connected to an output circuit SY1 to SY4 specific to each of them, and each output circuit comprises for example a mixing circuit (not represented) by means of which it receives the maintenance signals and the addressing signals which come from different channels.
  • the maintenance signals have a period p which can be for example 10 microseconds, during which the addressing of all the cells belonging to a selected line L1 to L4 takes place, that is to say of all the cells defined using a selected line electrode Y1 to Y4.
  • the addressing may for example be of a type such that, at this time to, the signal applied to this electrode Y1 (and only to this one) is a negative transition of erasure Tne, of duration (shown in broken lines) greater than the other transitions, and which causes all connected cells to go into the "off" state to this line electrode Y1.
  • Tne negative transition of erasure
  • This registration window is to put all cells connected to this row electrode in the "on” state, except those whose column electrodes X1 to X4 deliver a so-called “masking” signal (not shown) which effect of inhibiting the effects of the Cl registration window.
  • This operation can be repeated at each of the following periods, maintenance signals at times t2 and t3, t4 and t5, t6 and t7 where the addresses of lines L2, L3, L4 are thus produced respectively corresponding to the line electrodes Y2, Y3 , Y4.
  • the first line L1 is addressed again.
  • FIG. 3 illustrates the division of the image period PI into n sub-periods S1, S2, ..., Sn with n equal to 4 in the example.
  • the image period PI begins at time to with a first sub-period S1 which lasts a time To, and ends at a time ta.
  • a second sub-period S2 begins at time ta and lasts a time equal to 2 TB to end at time tb, where a third sub-period S3 begins.
  • the third sub-period S3 lasts a time equal to 4 TB and ends at an instant tc.
  • a fourth sub-period S4 begins at time tc and lasts a time equal to 8 TB, until the end of the period PI which marks the instant to 'of a following image period.
  • the sub-periods S1, S2, S3, S4 respectively have a duration of the order of 1.33 ms; 2.66 ms; 5.33 ms and 10.66 ms.
  • each line L1 to L4 can be addressed four times during the image period of this line, at the instants to, ta, tb and tc. It is therefore possible for each line L1 to L4 to put each cell C1 to C16, in the "off” state or in the "on” state at each of these instants, that is to say at each start of sub- periods S1 to Sn, and each cell retains this state until the start of the next sub-period where it is again put into one or the other of the two states "off", "on”.
  • the cells which are put in the "lit” state by the beginning of one or more sub-periods S1 to Sn they are activated by the maintenance signals and they produce light during the duration of this or these sub-periods. It is therefore possible, by combination of the n sub-periods S1 to Sn, to obtain 2 n- 1 different light emission durations for each cell, durations which each correspond to a desired luminance level for this cell during the image period PI, plus the zero luminance level which corresponds to the case of a cell which is put in the "off” state for all the sub-periods S1 to Sn of this image period.
  • This principle of controlling the luminance levels of the cells of a line L1 to L4 applies to all the lines, of course with a time shift from one line to another; for example from a line L1 to the next line L2 with an offset which corresponds to a period p of the maintenance signal as shown in FIG. 2, and which can for example be of the order of 10 microseconds.
  • the image period PI has the same duration for all the lines L1 to L4, whatever the number N of these lines, with a time offset for example of a period between two consecutive lines, an offset which is found in the distribution of sub-periods S1 to Sn.
  • the desired luminance levels for the different cells of each line L1 to L4 correspond to video input luminances which are coded and stored in the image management device 3, generally using n bits of different weights each corresponding to one of the sub-periods S1 to Sn.
  • the cells C1 to C16 in the "on" state being activated by the maintenance signals delivered by the line 1 control device, they constitute a load applied to the latter.
  • the maintenance signals can be produced in various ways, which are known per se.
  • the line control device comprises for this purpose at least one amplifier A which delivers the maintenance signals to the output circuits SY1 to SY4, either directly as shown in FIG. 1, or through several output stages (not shown) each assigned to supply several output circuits, that is to say several line electrodes Y1 to Y4.
  • the maintenance signals supplied by amplifier A must be supplied by amplifier A under a current which can vary considerably depending on the content of the image, i.e. depending on the number of cells which are in the "on” state.
  • the amount of charges applied actually at a given cell C1 to C16 depends on the overall content of the image. In other words, the higher the charge applied to amplifier A, the more the luminance of the cells in the "on" state which constitute this charge is reduced.
  • FIG. 4 represents an image formed mainly, of a peripheral zone Z1 with low luminance, and of a second zone Z2 with strong luminance and having constant video coding.
  • FIG. 4 represents an image formed mainly, of a peripheral zone Z1 with low luminance, and of a second zone Z2 with strong luminance and having constant video coding.
  • the second zone Z2 is made of two contiguous surfaces R1, R2 whose second R2 is located in the center of the first R1, and that it is desired to display on these two surfaces different but similar luminances: for example an I2 luminance corresponding to a video coding equal to 128 (in the case of an 8-bit video coding, that is to say with 8 sub-periods as previously explained) for the second surface R2, and a luminance l1 coded 127 for the first surface R1.
  • a known solution consists in reducing the source impedances and the connection impedances, and the impedances presented by the electrodes themselves. This is obtained by a choice and a selection of the components, by a drawing and a particularly careful realization of the paths of the discharge currents, as well as by multiplying the paths offered to the discharge currents, (in particular by putting several power transistors in parallel, at the level of the amplifier or amplifiers of maintenance signals (such as amplifier A) as well as in the output circuits (such as circuits SY1 to SY4).
  • the object of the present invention is to reduce the image defects linked to large variations in the charge and more particularly to reduce the highlight defects described above. To this end, it offers an inexpensive solution which consists in acting on the distribution of the activation times of the cells within an image period.
  • the invention relates to a method for controlling a display screen, the elementary image points of which are cells arranged in rows and columns.
  • the cells are put either in a state known as “extinct” or in a state known as “lit” in which they are activated and produce light.
  • the method consists for each line and during a given cycle time, to put each cell in the "off” state or in the "on” state at the start of n time intervals called activation sequences, as a function of 'a luminance level to be displayed by each cell for said cycle time.
  • the method is characterized in that it consists, for at least one line, in defining at least one range of luminance levels whose lower limit corresponds to the duration of an activation sequence, and in sharing this sequence in at at least two subsequences then, for the activation of cells having a luminance level included in said range, to replace this activation sequence by at least one activation sequence (S1 to S7) of shorter duration at which is added one of the two subsequences.
  • the invention also relates to an image display device having cells arranged in rows and columns, the cells being either in an "off” state or in an "on” state where they are activated and produce light, the cells which can be activated during activation times of different durations as a function of a luminance level which they must each display during a given cycle time, the display device being characterized in that it comprises means for distributing , within said cycle time, the activation times of cells of at least one line having luminance levels within a given range, so as to reduce the time during which these cells are likely to be the only to be activated.
  • FIG. 5 illustrates the evolution, during an image period PI (of 20 ms for example), of the charge constituted by the cells (C1 to C16) of a line such as the second line L2 for example shown in FIG. 4 , in a typical case presenting the defect of highlighting, and under the control of a process of the prior art.
  • the appearance of the first activation sequence S1 also begins, with which the luminance level cells 127 are set to the "on" state and are therefore activated. It follows that at time to, the charge Q of the line L2 has a first value Q1. These same cells are also activated by the following activation sequences S2, S3, S4, S5, S6, S7 which follow one another at times t1, t2, t3, t4, t5, t6. As in the previous explanations, for each of these activation sequences, its duration is half that of the following activation sequence. Consequently, the coded luminance level 127 is reached at the end of the seventh activation period S7 at time t7, and the load retains the first value Q1 until this time t7.
  • the coded luminance cells 127 are switched off, and the coded luminance cells 128 are set to the "on" state with the start of the eighth activation sequence S8, for the duration of the latter (which is worth 128 times the duration of the first activation period S1). Therefore, the charge varies abruptly at time t7, where it goes from the value Q1, to a second value Q2 much lower (of the order of 9 times in the example).
  • the difference in charge value between the time interval formed between instants to and t7, and the time interval formed between times t7 and tPF, will make the "highlights" pixels or cells coded at 128 compared to cells coded at 127.
  • Figures 6a and 6b illustrate the operation and the advantage resulting from the implementation of the invention.
  • Figure 6a also shows the evolution of the load of line L2, under the same conditions as those already explained with reference to Figure 5, but compared to the latter, it also shows a feature of the invention which consists in dividing the eighth S8 activation sequence into two subsequences S8A and S8B.
  • the two subsequences S8A, S8B are equal, so that there are now three intervals of the same weight, that is to say having identical durations, and being equal all three 64, which are: the seventh S7 activation sequence contained between times t6 and t7; the first sub-sequence S8A contained between instant t7 and an instant tm (instant tm which divides the duration of the eighth sequence S8 into two equal parts); and the second sub-sequence S8b contained between the instant tm and the instant tFP of the end of the image period PI.
  • the principle then consists in using the seventh sequence of activation S7 instead of the second subsequence S8B, to restore partially the luminance of the cells coded at 128. This means that the cells coded at 128 will be put in the state "lit” during the seventh S7 activation sequence, along with cells coded at 127.
  • FIG. 6b represents how the implementation of the invention manifests itself on the charge Q of the line L2 of cells, for the same conditions of luminance of the cells as in the examples of FIGS. 5 and 6a.
  • the charge Q acquires the same first high value Q1 that it had at this same instant to in the examples of FIGS. 5 and 6a.
  • the following activation sequences S2, S3, S4, S5, S6 are applied as before at times t1, t2, t3, t4, t5.
  • the instant t6 marks the end of the sixth activation sequence S6, and the beginning of the seventh activation sequence S7.
  • the line L2 comprises from time t6 more activated cells, and sees its charge increase at time t6 by an amount ⁇ Q, to pass to a third value Q3 (higher than the first value Q1 ), and keep this last value until time t7 when the seventh S7 activation sequence ends.
  • the cells coded at luminance 127 then pass to the "off" state which they keep until the end of the image period PI.
  • the instant tm which separates the time interval contained between the instant t7 and the end of the image period PI into two equal parts, marks the end of the first sub-sequence S8A, and the end of the activation of the cells coded 128.
  • the latter in fact were activated during the sixth activation sequence S6 (equal to 64) plus the first subsequence S8A which also is equal to 64. Consequently, at time tm, the charge changes to a value 0.
  • the eighth activation sequence S8 has therefore been replaced by one of its subsequences plus the seventh sequence S7.
  • the time during which the cells encoded 128 are activated corresponds to the duration of the first sub-sequence S8A, that is to say to 1/4 of the image period PI, whereas in the example of FIG. 5 relating to the prior art, this time activation of cells coded at level 128 is equal to half of the PI image period, and therefore has a double duration.
  • the correction made by the method of the invention is applied for luminance levels of value 128, but it can be applied in the same way to other values corresponding to the tilting of a bit, i.e. values which correspond to the duration of a single activation sequence S2, S3, S4, S5, S6, S7, S8 which correspond respectively to the value 2, 4, 8 , 16, 32, 64, 128.
  • S2, S3, S4, S5, S6, S7, S8 which correspond respectively to the value 2, 4, 8 , 16, 32, 64, 128.
  • an activation sequence S2 to S8 is divided into two sub-sequences of equal duration, one can either use one or the other.
  • the first S8A subsequence can be replaced by the second S8B subsequence of the same duration, so that part of the activation of the cells having the level 128 would have been produced between the instant tm and the end of the image period PI, and not between the instant t7 and the instant tm.
  • an activation sequence S3 to S8 into sub-sequences of unequal durations, if they are equal to the shortest activation sequence S1 or to a multiple of the latter.
  • the eighth activation sequence S8 which is equal to 128, in a first sub-sequence S8A '(not shown) equal to 32 and a second sub-sequence S8B' (not shown) equal to 96, l activation of cells with luminance level 128 must be produced at the same time as those whose level requires the use of the sixth activation sequence S6 (of value 32), then thereafter at the same time as those which require the use of the seventh S7 activation sequence (value 64), then finally they must be activated by the sub-sequence S8A '(value 32).
  • Such modifications of the distribution of the activation times of the cells within a PI image period can be made around a value, or several values of luminance levels, and can even concern groups of levels of the luminance, or ranges of luminance levels, since the lower limit of a range is that of a luminance level corresponding to the duration of a single activation sequence S2 to S8, and its upper limit is lower at the maximum luminance level.
  • the implementation of the method of the invention requires an additional addressing operation, by activation sequence having been shared.
  • This addressing is to be carried out at the start of each second sub-sequence, that is to say in the example shown in FIG. 6b where only the eighth activation sequence S8 is divided into two sub-sequences, the operation of addressing is to be performed at the start of the second sub-sequence S8B, to put the cells having level 128 in the "off" state.
  • additional addressing constitutes an additional underscan if it is repeated for all lines L1 to L5, and it must be controlled by the image management device 3 of the type of that shown in FIG. 1.
  • FIG. 7 schematically represents, by functional blocks, some of the functions provided by an image management device 3, which in itself is well known. It comprises for example a video input circuit 10 which performs an adaptation of the video signals, and classifies them for example for each line as a function of the luminance of each of the elementary image points, that is to say of the cells of the line considered.
  • the video input circuit 10 delivers video data which is applied to a video coding circuit 11, which, as a function of the luminance levels assigned to the cells of a given line L1 to L4, performs coding of each luminance.
  • This allows, using a coding table, to define the different activation sequences S1 to S8, by which each cell of a given line must be activated during an image period PI to restore the desired level of luminance .
  • the video coding circuit 11 delivers coded data to a memory circuit 12, which for example can include as many memory planes PM1 to PMn as the number n of activation sequences S1 to S8. Each activation sequence can also correspond to a memory map in which, for each line, the addresses of the cells which are to be put in the "on" state are stored.
  • the memory circuit 12 therefore has knowledge of the number of addressing operations (or sub-scans) to be carried out during an image period PI and, by exchanging information with the line control and column control devices 1, 2 (shown in Figure 1), it determines the execution of these addressing operations.
  • an additional memory plane PMS in the memory circuit 12 is useful, for storing in particular the addresses of the cells to be deactivated or activated during the second S8B sub-sequence.
  • FIG. 8 represents a coding table 13 making it possible, in a coding circuit 11, to assign some of the activation sequences S1 to S8 or all of these activation sequences, upon activation of the cells, depending on the level of luminance which they must each produce.
  • the coding table of FIG. 8 represents the case of FIG. 6b in which the eighth activation sequence S8 is divided into two sub-sequences S8A, S8B of equal durations, with a view to making corrections for the levels of luminance included from 128 to 191.
  • the eighth activation sequence S8 is divided into two sub-sequences S8A and S8B of equal values
  • a classical configuration must be found from the luminance level 192, (and up to the level maximum 255) which requires that a cell be in the "on" state for all the durations of the seventh and eighth activation sequences S7, S8, this latter sequence S8 being constituted by two parts S8A, S8B.
  • the example shown in the table in FIG. 8 applies to reducing the highlighting effect which is exerted on a minority of cells in the "lit” state when there is a transition in a line L1 to L4 around luminance level 128, between a large number of cells in the "lit” state and a small number of cells in the "lit” state, but this method can operate at other luminance values, corresponding to the tilting of a bit, for example 64, 32 etc., that is to say corresponding to an activation sequence value.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Power Engineering (AREA)
  • Plasma & Fusion (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
  • Gas-Filled Discharge Tubes (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)
  • Control Of Gas Discharge Display Tubes (AREA)
EP97400390A 1996-02-27 1997-02-21 Ansteuerungsverfahren für einen Anzeigebildschirm nach dem Prinzip der Modulation der Lichtemissionszeit und Anzeigevorrichtung, die dieses Verfahren verwendet Withdrawn EP0793213A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9602394 1996-02-27
FR9602394A FR2745411B1 (fr) 1996-02-27 1996-02-27 Procede de commande d'un ecran de visualisation d'image utilisant le principe de la modulation de duree d'emission de lumiere, et dispositif de visualisation mettant en oeuvre le procede

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EP0793213A1 true EP0793213A1 (de) 1997-09-03

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EP97400390A Withdrawn EP0793213A1 (de) 1996-02-27 1997-02-21 Ansteuerungsverfahren für einen Anzeigebildschirm nach dem Prinzip der Modulation der Lichtemissionszeit und Anzeigevorrichtung, die dieses Verfahren verwendet

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US (1) US6034654A (de)
EP (1) EP0793213A1 (de)
JP (1) JPH09237062A (de)
KR (1) KR100420019B1 (de)
FR (1) FR2745411B1 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0833299A1 (de) * 1996-09-25 1998-04-01 Nec Corporation Graustufenvorstellungsmethode und Graustufenanzeigegerät dafür

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1520587B (zh) * 2001-06-23 2010-04-28 汤姆森许可贸易公司 对视频图像进行处理的设备及其方法
FR2896324A1 (fr) * 2006-01-17 2007-07-20 St Microelectronics Sa Procede de traitement, par exemple d'insertion des couleurs d'une image numerique et dispositif correspondant

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0444962A2 (de) * 1990-03-02 1991-09-04 Hitachi, Ltd. Farbtonwiedergabe-Verfahren und Gerät zur Durchführung des Verfahrens
EP0674303A2 (de) * 1990-11-28 1995-09-27 Fujitsu Limited Schaltung zur Ansteuerung einer flachen Anzeigevorrichtung mit Helligkeitsabstufung

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5151690A (en) * 1987-08-13 1992-09-29 Seiko Epson Corporation Method and apparatus for driving a liquid crystal display panel
US5642128A (en) * 1987-10-02 1997-06-24 Canon Kabushiki Kaisha Display control device
US5233447A (en) * 1988-10-26 1993-08-03 Canon Kabushiki Kaisha Liquid crystal apparatus and display system
JPH03132692A (ja) * 1989-10-18 1991-06-06 Matsushita Electric Ind Co Ltd 液晶表示装置の駆動方法及びその駆動回路

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0444962A2 (de) * 1990-03-02 1991-09-04 Hitachi, Ltd. Farbtonwiedergabe-Verfahren und Gerät zur Durchführung des Verfahrens
EP0674303A2 (de) * 1990-11-28 1995-09-27 Fujitsu Limited Schaltung zur Ansteuerung einer flachen Anzeigevorrichtung mit Helligkeitsabstufung

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0833299A1 (de) * 1996-09-25 1998-04-01 Nec Corporation Graustufenvorstellungsmethode und Graustufenanzeigegerät dafür
EP1764767A3 (de) * 1996-09-25 2007-05-30 Pioneer Corporation Graustufendarstellungsverfahren und Graustufenanzeigevorrichtung

Also Published As

Publication number Publication date
FR2745411A1 (fr) 1997-08-29
KR100420019B1 (ko) 2004-06-16
JPH09237062A (ja) 1997-09-09
US6034654A (en) 2000-03-07
FR2745411B1 (fr) 1998-04-03
KR970064173A (ko) 1997-09-12

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