EP1739650A1 - Driving method of a passive matrix display device with multi-line selection - Google Patents

Driving method of a passive matrix display device with multi-line selection Download PDF

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Publication number
EP1739650A1
EP1739650A1 EP20050300538 EP05300538A EP1739650A1 EP 1739650 A1 EP1739650 A1 EP 1739650A1 EP 20050300538 EP20050300538 EP 20050300538 EP 05300538 A EP05300538 A EP 05300538A EP 1739650 A1 EP1739650 A1 EP 1739650A1
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Prior art keywords
lines
group
line
transmitters
selected
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Withdrawn
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EP20050300538
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German (de)
French (fr)
Inventor
Sylvain Thiebaud
Jean-Paul Dagois
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Thomson Licensing SAS
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Thomson Licensing SAS
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Priority to EP20050300538 priority Critical patent/EP1739650A1/en
Publication of EP1739650A1 publication Critical patent/EP1739650A1/en
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    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20Control 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
    • G09G3/22Control 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
    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20Control 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
    • G09G3/22Control 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
    • G09G3/30Control 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 electroluminescent panels
    • G09G3/32Control 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 electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
    • G09G3/3208Control 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 electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
    • G09G3/3216Control 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 electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED] using a passive matrix
    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00Command of the display device
    • G09G2310/02Addressing, scanning or driving the display screen or processing steps related thereto
    • G09G2310/0202Addressing of scan or signal lines
    • G09G2310/0205Simultaneous scanning of several lines in flat panels
    • G09G2310/021Double addressing, i.e. scanning two or more lines, e.g. lines 2 and 3; 4 and 5, at a time in a first field, followed by scanning two or more lines in another combination, e.g. lines 1 and 2; 3 and 4, in a second field
    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00Control of display operating conditions
    • G09G2320/04Maintaining the quality of display appearance
    • G09G2320/043Preventing or counteracting the effects of ageing
    • GPHYSICS
    • G09EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09GARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2340/00Aspects of display data processing
    • G09G2340/04Changes in size, position or resolution of an image
    • G09G2340/0407Resolution change, inclusive of the use of different resolutions for different screen areas
    • G09G2340/0414Vertical resolution change

Abstract

A method in which, to display an image comprising N rows and P columns of pixels or subpixels, each represented by a video data, the device comprising an array of light emitters, each associated with a pixel or subpixel, successively selects groups comprising at least two adjacent lines of transmitters (except for the first and / or last), each group, except the first or the last, comprising all the lines of the preceding group except the first one and further comprising the line following the last one of this preceding group, and during each selection of a group of lines, the emitters of this selected group are sent the video data of the emitters of a central line of this group.
This significantly improves the brightness of the display by limiting the degradation of its vertical resolution.
Figure imgaf001

Description

  • The invention relates to a method for controlling image display devices, in particular passive matrix light emitting diode (OLED) or "Field Emission Display" (FED) panels. .
  • Such image display devices generally include:
    • a network of light emitters arranged in rows and columns; these emitters may be light-emitting diodes; such diodes are provided with two electrodes for their power supply, anode and a cathode; in the case of "FED"("Field Emission Display"), these emitters are cathodoluminescent triodes; such emitters are provided with three electrodes: an emitting cathode, a gate, and an anode coated, at least partially, with cathodoluminescent material; the anode is generally common to all panel transmitters;
    • line selection means adapted to connect transmitters of one or more lines to a common line feed electrode; these selection means generally comprise a network of line electrodes, and for each line electrode, a controllable switch capable of connecting this line electrode to the common line electrode; the emitters of the same line each have an electrode of a first type connected to the same line electrode;
    • an array of column electrodes; the emitters of the same column each have an electrode of a second type connected to the same column electrode, each connecting emitters of the same column,
    • and means for addressing the emitters which are capable of generating, between the common supply electrode of the lines and column electrodes, signals adapted to drive the transmission of the selected emitters; in the case of light-emitting diodes, it is possible, for example, to control voltage or current; in the case of current control, each column electrode is for example equipped with a voltage controllable current generator. When implementing a conventional method for controlling such image display panels, as indeed for controlling optical valve panels such as LCDs ("Liquid Crystal Display"), each line electrode is successively selected. of the panel, and, whenever a line electrode is selected, is simultaneously addressed to each transmitter or valve of this line, via the column electrode to which he or she is connected, a signal that is a function of the video data of the pixel or sub-pixel of the image to which this emitter or this optical valve is associated.
  • For the control of billboards with a network of optical valves, such as liquid crystal valves, the prior art discloses methods known as "MLS" ("Multi-Line Selection"), or "MLA" ( «Multi-Line
  • Adressing "), wherein, the line electrodes being divided into different groups (generally two or three electrodes), each group of line electrodes is successively selected, and each time a group of line electrodes is selected, as above, is simultaneously addressed to each of the column electrodes a specific signal to this column; thus, when several optical valves of the same column are served by line electrodes which belong to the same group and are selected simultaneously, these different valves are then addressed by the same signal. The document EP0585466 describes the case, in particular in FIG. 25, where three electrodes of adjacent lines are simultaneously selected; the document US6084563 the case in FIG. 23, where two electrodes of adjacent lines are simultaneously selected; the document EP0598913 discloses an improvement in which each selection period of a group of lines is subdivided into gray gradation subperiods; the document US5262881 describes a particular mode of addressing and calculation of the signal addressed to each column as a function of the lines selected simultaneously; the documents US6421040 , EP0990940 , EP1365384 and EP1396838 describe improvements to the Liquid Crystal Display (LCD) displays of this control method with simultaneous selection of multiple lines.
  • The documents US2003-179171 and W02004-088568 describe the use of this same "MLS" or "MLA" method only in the context of PWM or Pulse Width Modulation, where the signal addressed to the optical valves or panel transmitters The display is a duration signal, more precisely a voltage or current pulse of constant amplitude but of variable duration. These last two documents indicate that the "MLS" or "MLA" method combined with "PWM" modulation is applicable to electroluminescent display panels, in particular to OLED or PLED panels.
  • Finally, the document US5781169 discloses the use of a consecutive two-line selection method for deinterleaving a video signal; in this case, the video signal successively delivers a first partial image comprising only the odd lines of the pixels of this image, then a second partial image, complementary to the first, comprising only the even lines of the pixels of this image, and thus right now ; according to this document, when the first partial image is displayed, each odd line and, at the same time, the following even line are selected, by sending to the emitters of these lines the signals corresponding to the selected odd line; then, when displaying the second partial image, selecting each even line and simultaneously the following odd line, by sending to the emitters of these lines the signals corresponding to the selected even line; such a method makes it possible to simply recompose a complete image from each partial image.
  • The object of the invention is to substantially improve the brightness of the display panels, in particular passive matrix electroluminescent panels, by using a specific control method in which, to display an image, a plurality of lines is successively selected.
  • For this purpose, the subject of the invention is a method for controlling an image display device, comprising a network of light transmitters arranged in N adjacent rows and in columns, line selection means capable of connecting emitters of several lines to a common feed electrode of the lines, column electrodes connecting, each, emitters of the same column, and means addressing the emitters capable of generating, between said common feed electrode of the rows and the column electrodes, signals adapted to drive the emitting of the selected emitters,
    • ... in which, each transmitter being associated with a pixel or sub-pixel of the images to be displayed, video data being attached to each pixel or sub-pixel of each image to be displayed, and said transmitter lines being grouped into different groups of which at least one has a plurality of lines,
    • ... to display each image,
      • with the aid of said selection means, the transmitters of all the lines of, successively, each group, are simultaneously selected by connecting the said common line feed electrode to these transmitters of the lines of the selected group,
      • and, whenever the emitters of the lines of a group are selected, using said addressing means, between said common line feed electrode and each of the column electrodes which is connected to at least one of said selected transmitters, a signal adapted to drive the emission of these transmitters is generated as a function of the video data of the pixels or sub-pixels associated with these transmitters,
      characterized in that said transmitter lines are divided into N groups which all differ from each other by at least one line.
  • The current or voltage signals generated by the addressing means may be adapted so that the selected transmitters emit proportionally to the amplitude of these signals, in which case the control of the panel is carried out by amplitude modulation. Conversely, these signals can be adapted to modulate the transmission duration of the selected transmitters during each selection period, in which case the control of the panel is carried out by modulation of duration as in the aforementioned documents US2003-179171 and W02004-088568 , who cite the use of "MLS" or "MLA" methods for controlling OLED panels.
  • Since, according to the invention, there are as many groups as there are rows of transmitters, each line belonging to a group comprising a plurality of lines generally belongs to at least one other group.
  • Thus, each transmitter is generally addressed several times during the display of an image, which allows to significantly increase the brightness of the images displayed, and / or to limit the load of the transmitters for a brightness comparable to that of the prior art, and thus improve their service life.
  • Preferably, the different lines of each group having a plurality of lines are adjacent. This arrangement makes it possible to improve the vertical image display resolution and / or to simplify the calculation of the addressing signals of the transmitters with respect to the video data of the pixels or subpixels associated with them.
  • Preferably, each group comprises M> 1 adjacent lines except, optionally, the M-1 groups among the first and / or last, said groups are ordered in the same order as the lines, and any two consecutive groups differ only in a single line. This means that, if the lines are numbered from 1 to N in the order of the adjacent lines, the first group comprises one or more adjacent first lines, the last group comprises one or more adjacent last lines, and any two groups comprising the same number of lines are ordered according to the average of the line numbers they include. Obviously, M is generally much lower than N.
  • Preferably, each group of M lines which follows another group of M lines comprises all the lines of this preceding group except the first line of this group, and furthermore comprises the line which follows the last line of this preceding group. Thus, all the lines except possibly the first and / or last M-1 are addressed M times for the display of each image, which makes it possible to substantially increase the display brightness of the images. If Tt is the duration of display of each image, the total and overall duration of selection of each selected line M times is then MxTt / N. It can thus be seen that, with respect to conventional addressing methods, the invention therefore makes it possible to increase the addressing time and therefore the emission of emitters by almost a factor M. The invention therefore makes it possible to increase substantially the brightness of the images displayed, and / or to limit the load of the transmitters for a brightness comparable to that of the prior art, and thus improve their service life.
  • Preferably, M = 2. Indeed, this case generally corresponds to the best compromise between the high vertical resolution of the image display and the high display brightness.
  • Preferably, whenever the transmitters of the lines of a group having a plurality of lines are selected, using said addressing means, between said common line feed electrode and each of the column electrodes which is connected to the selected transmitters of this column, a signal is generated adapted to cause the transmission of each transmitter of one of said address reference lines of this group as a function solely of the video data of the pixel or subpixel associated with this transmitter. This signal may also be a function of other parameters than this video data, but it does not depend on the video data of the other selected transmitters of this column.
  • The signals that are addressed independently of each other to each column electrode when selecting the transmitters of all the lines of a group are therefore adapted so that the transmitters of one of the lines of this group transmit each in proportion to the video data of the pixel or sub-pixel with which it is associated; this means that the "video word" that is sent - in parallel - on the column electrodes corresponds to the "video word" of one of the selected lines (especially when the selected group comprises several lines), and not, for example , to an average of the "video words" of these lines addressed simultaneously; the term "video word" means a multiplet formed by the set of signal values to be simultaneously addressed to the different transmitters of the same line so that each transmitter of this line emits in proportion to the video data of the pixel or sub-pixel to which this issuer is associated.
  • Preferably, each line of emitters of the panel is used only once as an address reference line. This optimally uses the video data available for displaying images.
  • Preferably, each time the emitters of the lines of a group comprising M lines are selected, said reference line of address of this group is the central line of the group if M is odd, is one of the two central lines of this group if M is even.
  • For example, if M = 3, the address reference line of each group with three lines will be the second line of this group. If M = 3, the first group and the last group will preferably have only two lines.
  • If M = 4, the addressing reference line of each group with four lines will be the second or third line of this group.
  • If M = 5, the addressing reference line of each group with five lines will be the third line of this group. If M = 5, the first group and the last group will preferably comprise only three lines, the second group and the penultimate group will preferably comprise only four lines; for the first two lines, the first line and the second line will preferably be used respectively as the address reference line; for the last two lines, the penultimate line and the last line are preferably used respectively as the address reference line. Thus, each line of the panel is used one time as an address reference line for each image display.
  • If M = 2 and the reference reference line of each group is the first line of each group, the last group will preferably have only one line. On the other hand, if M = 2 but the reference reference line of each group is the last line of each group, the first group will preferably comprise only one line which obviously serves as a reference line for each group. addressing for this group.
  • The subject of the invention is therefore a method for controlling an image display device in which, to display an image comprising N rows and P columns of pixels or sub-pixels, each represented by a video datum, the device comprising an array of light emitters, each associated with a pixel or sub-pixel, groups of at least two adjacent lines of emitters are successively selected, each group, except possibly the first selected, comprising all the lines of the emitter, previous group except the first one in this group and further comprising the line following the last line of the previous group selected (if it does not exist, preferably, then the first line), and, during each selection of a group of lines, the emitters of this selected group are sent the video data of the transmitters of the first line of this group which corresponds in the second row of the previously selected group.
  • Preferably, said display device to which the method according to the invention applies is a passive matrix. This method indeed applies in preference to devices where the emitters emit light only during the addressing of the emitters, that is to say where the emitters are not provided with means for storing the values of the emitter. voltage or current signals addressed to them between the periods when they are addressed. This method therefore preferably applies to so-called "passive matrix" devices.
  • According to an advantageous variant of the method according to the invention, to display each image, in addition, before or after at least one selection of transmitters of all the lines of a group comprising a plurality of lines,
    • with the aid of said selection means, the transmitters of the addressing reference line of said group are selected simultaneously by connecting said common line supply electrode to the emitters of this line,
    • and, with the aid of said addressing means, between said common line feed electrode and each of the column electrodes which is connected to a selected emitter of this column, a suitable signal is generated to drive the emission of each transmitter of this line according to the video data of the pixel or subpixel associated with this transmitter.
  • By performing this complementary step of selecting a single line before or after the multi-line selection steps according to the invention, the vertical resolution of the image display is advantageously improved.
  • Then, if the panel comprises N lines, if the lines are divided into N groups of two lines (M = 2) except the first or the last group which comprise only one line, each line except possibly the first or the last belongs to two groups, if the duration of an image is Tt, if the duration of each conventional "uni-line" addressing phase is Tt / N and the duration of each "multi-line" addressing phase the invention is α.Tt / N, where 0 < α <1, then the total and global duration of selection of each line is (1+ α) .Tt / N.
  • This improvement of the invention optimizes the best compromise between the brightness of the display (α close to 1) and the vertical resolution of the definition of the display of images (α close to 0). Preferably, the value of the parameter α is adapted according to the type of images or video sequence to be displayed.
  • Preferably, the display device also comprises line electrodes each connecting transmitters of the same line, and the line selection means comprise controllable switches capable of connecting each line electrode to said common electrode. power lines to select transmitters connected to this line electrode.
  • The emitters may be light-emitting diodes. The invention then applies in particular to OLED and PLED panels.
  • The emitters may be catholuminescent triodes. The invention then applies to "FED" (Field Emission Display).
  • The invention will be better understood on reading the description which follows, given by way of nonlimiting example, and with reference to the appended figures in which:
    • FIG. 1 describes an exemplary image display device to which the control method according to the invention applies;
    • FIG. 2 represents the chronograms K1, K2, K3, K4 of the control signals of the selection switches S1, S2, S3, S4 during the first three stages of displaying an image by means of the device of FIG. 1 which is controlled according to an embodiment of the method according to the invention;
    • Figures 3 to 5 illustrate the state of the device of Figure 1 respectively during the first, the second, and the third display step corresponding to the timing of Figure 2;
    • FIG. 6 represents chronograms K1, K2, K3, K4 of the control signals of the selection switches S1, S2, S3, S4 during the first three steps of displaying an image by means of the device of FIG. 1 when piloted according to a variant of the method illustrated by FIGS. 2 to 5.
  • The figures representing chronograms do not take into account a scale of values in order to better reveal certain details that would not be clearly visible if the proportions had been respected.
  • An embodiment of the invention will now be described in the context of the display of a video sequence comprising a succession of images. Each image is partitioned in pixels; in the case of tri-chromium images, each pixel itself is subdivided into three adjacent sub-pixels belonging to the same line, one per primary display color. At each pixel or sub-pixel of any image of the video sequence, there is associated a video data representing for example a luminance value of this pixel or sub-pixel.
  • To visualize this video sequence, a display device is shown schematically in FIG. 1 which comprises a display panel provided with an array of light emitters, here organic electroluminescent diodes 1, which are arranged in lines 1, 2, 3, 4, ... and columns 1, 2, 3, 4, .... Each diode here comprises two electrodes for its power supply: anode and a cathode. In the case of triodes, as for example for FED, there are also two electrodes per transmitter for the modulation of the emission: the cathode and the gate. Each emitter, diode or triode, is associated with a pixel or sub-pixel of the image to be displayed.
  • This device also comprises video processing means (not shown) which make it possible to determine, for each transmitter, the value of a signal to be addressed between its two electrodes so that it emits an emittance radiation corresponding to the video data of the transmitter. pixel or sub-pixel with which it is associated; the emittance considered here is the average emittance integrated over the duration of an image (or frame duration Tt); the video processing means are adapted to associate a voltage signal with each video data.
  • The display panel is also provided with a network of N row electrodes Y1, Y2, Y3, Y4, ... and a network of P column electrodes X1, X2, X3, X4, ..., intended to supply the diodes (or to modulate the triodes). Each diode is thus connected by one of its electrodes to a line electrode and the other of its electrodes to a column electrode. The electrodes of one of the these networks are generally transparent, to let out the light emitted by the electroluminescent layer interposed between the anode and the cathode of each diode.
  • The anodes (or cathodes) of the diodes of the same line are connected to the same line electrode; the cathodes (or anodes) of the diodes of the same column are connected to the same column electrode; these networks thus make it possible to feed each diode, as a function of the value of the signal addressed between the line electrode and the column electrode to which this diode is connected. The display device also comprises addressing means 2 which, in the case of the diodes, also serve for their power supply. These means comprise a current generator 22 for each column, which is capable of generating a current in the column electrode to which it is connected and in transmitters which are connected to this electrode, and which is controllable by the signal of addressing this column. These means also include means 21 for controlling the duration of each of these generators: here, therefore, there is a modulation of the "PWM" ("Pulse Width Modulation") type.
  • The display device also comprises line selection means 3 adapted in a manner known per se for simultaneously selecting transmitters or diodes of several lines; for this purpose, these means 3 comprise controllable switches S1, S2, S3, S4, ... capable of connecting the common line supply terminal 31 to each of the line electrodes Y1, Y2, Y3, Y4, .. when the transmitters of these lines are selected. Here, the ends of the line electrodes to which these switches are connected are all arranged on the same side of the panel, so as to form a single line control block.
  • Referring to Figures 2 to 5, will now be described the display of any image of the video sequence, using the control method of the device according to the invention.
  • The N row electrodes Y1, Y2, Y3, Y4, ... are distributed in N groups G1, G2, G3, ....; the first group G1 comprises the electrodes Y1 and Y2; the group G2 comprises the electrodes Y2 and Y3; group G3 comprises electrodes Y3 and Y4; any group Gj comprises the electrodes Yj and Y (j + 1); the last group GN only includes the electrode Y N.
  • It can thus be seen that the row electrodes of each of the groups are adjacent, and that each line electrode, except the first one, belongs to at least two groups. Each group except the last thus includes two line electrodes.
  • The duration T t of a frame is divided into N intervals I1, I2, I3, I4, ... of equal times T t / N.
  • S1, S2, S3, S4, etc. are then applied to the control, respectively the control signals K1, K2, K3, K4, as shown in FIG.
    • with reference to FIG. 3, during the first interval I1, the switches S1 and S2 are thus closed so as to select the row electrodes Y1, Y2 of the first group G1: the common line electrode 31 is therefore connected simultaneously to the electrodes line Y1 and Y2 of the first group G1. The other selection switches S3, S4 remain open. Still during this first interval I1, one applies to the diodes 1 of the lines of the first group G1, namely lines 1 and 2, the video data for the diodes of one of the lines of this group, namely the line 1 which corresponds to the line electrode Y1. With the aid of the supply and addressing means 2, therefore, between the common line electrode 31 and each of the column electrodes X1, X2, X3, X4, a constant current is generated for a suitable duration. to obtain, from each of the diodes of line 1, an average luminance emission L1 corresponding to the luminance of the pixel or sub-pixel associated with these diodes in the image to be displayed. Mean luminance means the luminance averaged over the duration Tt of displaying an image. As several lines are selected, this signal also causes the emission of each of the diodes of the other lines of the group G1, here of the line 2, which are connected to the same column electrodes; in each column, a diode of line 2 belonging to group G1 thus emits with the same luminance L1 as the diode of line 1.
    • with reference to FIG. 4, during the second interval I2, the switches S2 (as before) and S3 are thus closed so as to select the row electrodes Y2 and Y3 of the second group G2: the common line electrode 31 is therefore simultaneously connected to the line electrodes Y2 and Y3 of the second group G2. The other selection switches S1, S4 remain open. Also during this second interval I2, the lines of the second group G2, namely lines 2 and 3, are applied to the diodes, the video data for the diodes of the first line of this group, namely the line 2 corresponding to the Y2 line electrode. Thus, between the common line electrode 31 and each of the column electrodes X1, X2, X3, X4, a constant current is generated for a duration adapted to obtain, from each of the diodes of the line 2, a transmission of luminance L2 corresponding to the luminance of the pixel or sub-pixel associated with these diodes in the image to be displayed. As several lines are selected, this voltage signal also causes the emission of each of the diodes of the other lines of the group G2, here of the line 3, which are connected to the same column electrodes; in each column, a diode of the line 3 which belongs to the group G2 thus emits with the same luminance L2 as the diode of the line 2.
    • with reference to FIG. 5, during the third interval 13, the switches S3 (as before) and S4 are thus closed so as to select the row electrodes Y3 and Y4 of the third group G3: the common line electrode 31 is therefore simultaneously connected to the line electrodes Y3 and Y4 of the third group G3. The other selection switches S1, S2 remain open. Also during this third interval 13, the lines of the third group G3, namely lines 3 and 4, are applied to the diodes, the video data intended for the diodes of the first line of this group, namely the line 3 corresponding to the Y3 line electrode. Thus, between the common line electrode 31 and each of the column electrodes X1, X2, X3, X4, a constant current is generated for a duration adapted to obtain, from each of the diodes of the line 3, a transmission of luminance L3 corresponding to the luminance of the pixel or subpixel associated with these diodes in the image to be displayed. As several lines are selected, this voltage signal also causes the emission of each of the diodes of the other lines of the group G3, here of the line 4, which are connected to the same column electrodes; in each column, a diode of line 4 belonging to group G3 thus emits with the same luminance L3 as the diode of line 3.
  • These steps are reiterated for all the groups of lines of the panel so that, after having scanned all the groups of row electrodes, an image is displayed.
  • The same control method is used for all the successive images until the video sequence is displayed.
  • According to the invention, the diodes of each line of the panel (except the first line) are therefore addressed twice for the display of each image:
    • a first time with the video data that correspond to the transmitters of the previous line,
    • a second time with the corresponding video data.
  • Compared to conventional control methods where the diodes of each line are addressed only once during the display of an image, the total duration of addressing and therefore of supply of each diode, except those of the first line, is doubled: 2 x Tt / N (instead of 1 x Tt / N in the prior art), which allows:
    • to significantly increase the brightness of the billboard,
    • or to limit the load on the diodes for the same brightness as in the prior art, and thus improve their service life.
  • Advantageously, the method according to the invention does not induce significant losses of vertical resolution in the definition of the display of images. In order to compensate for the "deficit" of the overall duration of supply of the diodes of the first line, the duration of addressing of the first line is preferably doubled.
  • Advantageously, the method according to the invention makes it possible to use conventional addressing means ("column drivers") for the electroluminescent display panels.
  • In the method which has just been described, it can be seen that the total and overall duration of addressing, that is to say of supply, of the emitters of each line is a multiple (integer) of the elementary selection period. or Tt / N addressing, here: 2 x Tt / N; in order to obtain intermediate values of the total and global addressing time, for example in order to obtain a value (1 + α) x Tt / N, with 0 <α <1, as an alternative to the embodiment of the invention. invention which has just been described and with reference to FIG. 6, two "multi-line" selection periods MLS, as previously described, are introduced. period called "SLS" selection "uni-line" classic of the prior art. For this purpose, we shorten each period "MLS" which lasts more than α x Tt / N; each period "SLS" therefore lasts (1-α) x Tt / N.
  • According to the timing diagram of Figure 6, each line thus presents:
    • two "MLS" periods of time selection, shorter than before,
    • an SLS period.
  • The total and overall address and power duration of the emitters of each line is therefore equal to (1 + α) xTt / N, with 0 <α <1.
  • This variant of the embodiment of the invention obviously requires specific addressing means.
  • This variant of the invention optimizes the compromise between the brightness of the display (α close to 1) and the vertical resolution of the definition of the display of images (α close to 0). Preferably, the value of the parameter α is adapted according to the type of images or video sequence to be displayed.
  • The present invention has been described with reference to a passive matrix electroluminescent panel; it is obvious to those skilled in the art that it can be applied to other types of billboards whose transmitters do not have a "memory" effect enabling them to transmit between the selection periods , such as Field Emission Display (FED) type panels, without departing from the scope of the claims below.

Claims (9)

  1. Method for controlling an image display device, device comprising an array of light emitters (1) arranged in N adjacent rows and in columns, line selection means (3) able to link transmitters several lines to a common feed electrode lines (31), column electrodes (X1, X2, X3, X4, ...) each connecting transmitters of the same column, and means of addressing (2) emitters capable of generating, between said common feed electrode of the lines (31) and column electrodes (X1, X2, X3, X4, ...), signals adapted to drive the emission of selected transmitters,
    ... in which, each transmitter being associated with a pixel or sub-pixel of the images to be displayed, video data being attached to each pixel or sub-pixel of each image to be displayed, and said transmitter lines being grouped into different groups (G1, G2, G3, G4, ...) of which at least one has a plurality of lines,
    ... to display each image,
    with the aid of said selection means (3), the transmitters of all the rows of, successively, each group, are simultaneously selected by connecting the said common line supply electrode (31) to these transmitters of the lines of the selected group. ,
    and, whenever the transmitters of the lines of a group are selected, by means of said addressing means (2), between said common line supply electrode (31) and each of the column electrodes ( X1, X2, X3, X4, ...) which is connected to at least one of said selected transmitters, a signal adapted to cause the transmission of these transmitters is generated as a function of the video data of the pixels or sub-pixels associated with these transmitters. transmitters,
    characterized in that said transmitter lines are divided into N groups (G1, G2, G3, G4, ..., G N ) which all differ from each other by at least one line.
  2. Method according to claim 1, characterized in that the different lines of each group which comprises a plurality of lines are adjacent.
  3. A method according to claim 1 characterized in that each group comprises M> 1 adjacent lines except, optionally, the M-1 groups among the first and / or last, in that said groups are ordered in the same order as the lines, and in that any two consecutive groups differ only in one line.
  4. Method according to Claim 3, characterized in that each group of M lines which follows another group of M lines comprises all the lines of this preceding group except the first line of this group, and furthermore comprises the line which follows the last line of this previous group.
  5. Process according to Claim 3 or 4, characterized in that M = 2.
  6. Method according to any one of the preceding claims, characterized in that , each time the emitters of the lines of a group comprising a plurality of lines are selected, by means of said addressing means (2), between said electrode common supply line (31) and each of the column electrodes (X1, X2, X3, X4, ...) which is connected to the selected transmitters of this column, a signal is generated adapted to cause the emission of each emitter of one of said address reference lines of this group based solely on the video data of the pixel or subpixel associated with this transmitter.
  7. Method according to claim 6, characterized in that each line of emitters of the panel is used once as an address reference line.
  8. A method according to claim 6 or 7 when claim 6 is dependent on any one of claims 3 to 5 characterized in that , each time the transmitters of the lines of a group having M lines are selected, said reference line of addressing this group is the central line of the group if M is odd, is one of the two central lines of this group if M is even.
  9. Method according to any one of the preceding claims, characterized in that said display device is a passive matrix.
EP20050300538 2005-06-30 2005-06-30 Driving method of a passive matrix display device with multi-line selection Withdrawn EP1739650A1 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009011767A1 (en) * 2007-07-18 2009-01-22 Eastman Kodak Company Reduced power consumption in oled display system
US7940236B2 (en) 2007-04-20 2011-05-10 Global Oled Technology Llc Passive matrix electro-luminescent display system

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WO1993006585A1 (en) * 1991-09-17 1993-04-01 Copytele, Inc. Method for writing data to an electrophoretic display panel
US5742270A (en) * 1996-03-06 1998-04-21 Industrial Technology Research Institute Over line scan method
US20010038374A1 (en) * 2000-04-19 2001-11-08 Koninklijke Philips Electronics N.V. Matrix display device with improved image sharpness
EP1408479A2 (en) * 2002-10-09 2004-04-14 Canon Kabushiki Kaisha Image display apparatus
US20050024302A1 (en) * 2003-07-30 2005-02-03 Hitachi., Ltd. Image display device

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Publication number Priority date Publication date Assignee Title
WO1993006585A1 (en) * 1991-09-17 1993-04-01 Copytele, Inc. Method for writing data to an electrophoretic display panel
US5742270A (en) * 1996-03-06 1998-04-21 Industrial Technology Research Institute Over line scan method
US20010038374A1 (en) * 2000-04-19 2001-11-08 Koninklijke Philips Electronics N.V. Matrix display device with improved image sharpness
EP1408479A2 (en) * 2002-10-09 2004-04-14 Canon Kabushiki Kaisha Image display apparatus
US20050024302A1 (en) * 2003-07-30 2005-02-03 Hitachi., Ltd. Image display device

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7940236B2 (en) 2007-04-20 2011-05-10 Global Oled Technology Llc Passive matrix electro-luminescent display system
WO2009011767A1 (en) * 2007-07-18 2009-01-22 Eastman Kodak Company Reduced power consumption in oled display system
US8269798B2 (en) 2007-07-18 2012-09-18 Global Oled Technology Llc Reduced power consumption in OLED display system

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