EP0692780A1 - Flüssigkristallanzeigeeinrichtung mit aktiver Matrix und unterteilter Gegenelektrode - Google Patents

Flüssigkristallanzeigeeinrichtung mit aktiver Matrix und unterteilter Gegenelektrode Download PDF

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Publication number
EP0692780A1
EP0692780A1 EP95401662A EP95401662A EP0692780A1 EP 0692780 A1 EP0692780 A1 EP 0692780A1 EP 95401662 A EP95401662 A EP 95401662A EP 95401662 A EP95401662 A EP 95401662A EP 0692780 A1 EP0692780 A1 EP 0692780A1
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EP
European Patent Office
Prior art keywords
electrode
counter
column
during
pixels
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Withdrawn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
EP95401662A
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English (en)
French (fr)
Inventor
Louis Delgrange
Ambroise Parker
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Sagem SA
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Sagem SA
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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
    • G09G3/34—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 by control of light from an independent source
    • G09G3/36—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 by control of light from an independent source using liquid crystals
    • G09G3/3611—Control of matrices with row and column drivers
    • G09G3/3648—Control of matrices with row and column drivers using an active matrix
    • G09G3/3655—Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors
    • 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
    • G09G3/34—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 by control of light from an independent source
    • G09G3/36—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 by control of light from an independent source using liquid crystals
    • G09G3/3611—Control of matrices with row and column drivers
    • G09G3/3648—Control of matrices with row and column drivers using an active matrix
    • 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
    • G09G3/34—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 by control of light from an independent source
    • G09G3/36—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 by control of light from an independent source using liquid crystals
    • G09G3/3611—Control of matrices with row and column drivers
    • G09G3/3622—Control of matrices with row and column drivers using a passive matrix
    • G09G3/3625—Control of matrices with row and column drivers using a passive matrix using active addressing

Definitions

  • the present invention relates to liquid crystal display devices, of the so-called active matrix type, comprising a display screen having a thin layer of liquid crystals disposed between a planar counter electrode and electrodes (each defining a capacitor and an element of image, or pixel, with the counter electrode) arranged so that each of the pixels corresponds to a line and a column, each electrode being connected to a control element, such as a thin film transistor, allowing either bring it to the potential of a column conductor which is common to all the pixels of the column to which it belongs, or else to isolate it and make its potential floating, according to the voltage which is applied to a common line conductor to all control elements on the same line.
  • a control element such as a thin film transistor
  • Each control element thus constitutes a switch which, in the closed state, makes it possible to bring the electrode to the potential of the column conductor and, in the open state, isolates the electrode.
  • the polarity of the voltage applied to the capacitors is generally reversed at regular intervals, for example at the image refresh rate.
  • the mean value, over time, of the voltage applied to the capacitor of each pixel is zero.
  • the invention is also applicable to color display screens, having at least three sets of pixels, respectively green, red and blue.
  • Each of the L line conductors and each of the C column conductors is connected to a driver circuit which determines the voltage applied to the conductor.
  • the present invention aims to provide a device of the type defined above better meeting those previously known to the requirements of practice, in particular in that it makes it possible to reduce the number of driving circuits.
  • This arrangement makes it possible to reduce the number of drive circuits in one of the two directions; in addition, it reduces the number of connections to be made between the driver circuits and the screen itself, which also results in an increase in the screen opening rate, that is to say the ratio between the useful display area and the total area.
  • the light transmission value of a pixel can be controlled in isolation although two lines (or more generally n lines) are controlled by the same conductor, or two columns (or more generally n columns) are controlled by the same conductor.
  • the command mode can then be of the same kind as above, but transposed to the case of the columns.
  • the command mode shows a quadratic error.
  • the latter can in particular be corrected by providing each drive circuit to perform at least one n + 1 th sequence, during which the column conductors are brought to the product of the same quadratic error correction voltage by the terms successive of an additional binary code with zero mean value, orthogonal to the other codes. This correction mode is possible because the error is the same for all the pixels in the group assigned to the same column.
  • the conventional active matrix display screen comprises a thin layer of liquid crystals placed between two transparent slides.
  • the assembly thus formed is mounted between a polarizer and an analyzer.
  • One of the blades carries a single counter-electrode, which constitutes one of the armatures 20 of the capacitors each forming an image element or pixel.
  • the other transparent plate carries control electrodes 22 each defining a pixel and constituting capacitors with the counter electrode 20.
  • These electrodes can be formed by transparent conductive deposits.
  • FIG. 1 also shows a conventional control mode.
  • Each pixel is controlled by a thin-film field effect transistor (usually designated by the abbreviation TFT).
  • All the transistors T11, T12, T13, of the same line L1 are made simultaneously conductive by carrying the line conductor L1 corresponding to a determined potential (for example +15 Volts) while the line conductors of all the other lines are brought to a blocking potential of the transistors (for example -15 Volts).
  • the pass-through transistors communicate the voltage V c of the column conductor corresponding to the associated electrode 22.
  • the information constituted by the applied voltage V c is then kept for the duration of an image, the discharge time constant of the capacitor being chosen to be sufficiently long for this purpose.
  • the column conductors are controlled from a shift register 24 constituting line memory, in which the advance is caused by a clock signal originating from a time base 26.
  • the data input 28 of the shift register receives the signal via a sampler 30 also controlled by the time base 26.
  • a buffer memory 32 Once all the information corresponding to a line has been received, it is transferred to a buffer memory 32.
  • the content of all the cells of this memory is simultaneously applied to the column conductors C1, C2, ... by driving circuits 341, 342, ..., on receipt of a command from the time base 26.
  • the line which is to receive the information is selected by addressing using the drive circuits of the line conductors 36.
  • the potential of the counter-electrode is fixed by a source 37, generally in alternation at values + V ce and - V ce .
  • each drive circuit, or "driver”, of lines is assigned to two lines, generally adjacent because this solution is the simplest in terms of connections with the line "drivers".
  • the first output of the driver circuits 36 is connected to the conductor of lines L1 and L2, the second output to the conductor of lines L3 and L4, etc.
  • the counter electrode is split into two parts CE1 and CE2 assigned to the lines in such a way that the same line does not have both the same line conductor and the same counter electrode part.
  • the physical distribution of the conductors and electrodes and the distribution of the masks used to make them can be those given diagrammatically in FIG. 3.
  • the ranges indicated denote the electrodes which define the pixels, which can be red R, green V and blue B pixels.
  • Each electrode is extended by a protuberance which constitutes the drain, such as D, of a respective thin film transistor.
  • the same column conductor, C1 for example, attacks the sources, such as S, of field effect transistors belonging to a single column.
  • a track forming a line conductor constitutes the gates of the transistors of two adjacent lines.
  • the same line conductor L12 constitutes, in the case of FIG. 3, the grid of the field effect transistors of the pixels of the two lines, generally successive, L1 and L2 of the matrix.
  • FIG. 5 shows another possible grouping, making it possible to simplify the etching of the two parts CE1 and CE2, using the distribution in plan of the line conductors and parts of the counter electrode shown in FIG. 4, where the elements corresponding to those of FIG. 2 have the same reference.
  • the control by the same line conductor, such as L123, of three transistors belonging to three lines successive L1, L2, L3, can then be produced by an etching of the kind shown in FIG. 7, which makes it possible to group the control transistors in a space of less congestion because only one etched track is necessary for 3 (and more generally n) lines.
  • Each column conductor such as C1 then has growths, each of which constitutes the common source of three transistors belonging to the same column and to three successive lines.
  • the electrodes of the three corresponding pixels have protuberances constituting the drains D1, D2 and D3 of the thin-film control transistors.
  • n 6
  • each line conductor will be assigned to two sets of three pixels R, G and B.
  • n 4 or more
  • extrapolation of the solution shown in Figure 6 remains possible but at the cost of high resistances for several parts. It is then possible to adopt a distribution of the parts of the counter-electrode in two layers (generally made of tin and indium oxide, or ITO) separated by a thin insulating film.
  • Each part of the counter-electrode may consist of a mosaic of separate blocks, etched on the same conductive layer and connected to respective conductors by via holes through an insulating film.
  • the number of counter-electrode parts will be equal to the product of the number of columns grouped by the number of lines grouped.
  • a particularly interesting solution no longer uses an isolated and individual command for each line for a time equal to the frame duration T r divided by the number of lines on the screen (followed by a holding time representing the rest of the frame duration ), but a global command from each group in turn.
  • T r the frame duration of the group considered are blocked except during the periods T a assigned to this group.
  • FIG. 10 it is possible to address each group of lines during the durations which belong to the periods T m of all the other groups.
  • the voltages V cej are then the products of the terms f1 to f6, multiplied by V ce .
  • the voltage of part CE1 will be, during consecutive periods T a :
  • the indices 1 to 8 only indicate a time step.
  • n 6 pixels of a column k, values a1gk, a2gk, ..., a6gk of a radiometric parameter, representative of the transmission to be given, but which can vary between -1 and +1, by applying , in column k, different voltages during at least six successive periods, and generally more to make a correction.
  • the voltage applied to a column conductor during an interval Ta will be constituted by the product of a reference voltage Vc by the sum of the products of the parameters for each pixel, by the terms of the code assigned to the corresponding line (and to the counter-electrode part).
  • Vc1gk, ..., Vc8gk are those which must be applied to the column k considered during each of the eight charge periods Ta of the six pixels of the column k and group g.
  • V RMS jgk Vce + 6.Vc - 2.a4gk.Vce.Vc where a4gk is between -1 and +1, and can take any intermediate value, when you want a display with gray, black and white, or unsaturated color values.
  • Vc and Vce we can modulate the light transmission of the point corresponding to any value between the off and on states, i.e. (V RMS ) jgk) can take any what value between Vce + 6.Vc - 2.Vce.Vc and Vce + 6.Vc + 2.Vce.Vc.
  • the counter electrode is further cut into n separate parts or elements CEk.
  • the first element CE1 is placed opposite columns 1 of each of the defined groups.
  • the second element CE2 is placed opposite the columns 2 of each of the groups defined, and so on, up to the nth counter-electrode CEn which is placed opposite the columns n of each of the defined groups.
  • the parts of the counter electrode CE1 are electrically connected together on the counter electrode plate.
  • the elements of the counter electrode CE2 are electrically connected together on the counter electrode plate, and so on until n, according to an arrangement which may be one of those given above.
  • the frame period Tr is further divided into periods Ti (eight in number, if the above code is used, of which six are used and one is used to compensate for the quadratic error.
  • the signal to be sent to the columns of group g during each of the eight periods Ti, without correction of the theoretical quadratic error, is defined in the same way as above; he is
  • Vcjg1 Vc. (+ ajg1 + ajg2 + ajg3 + ajg4 + ajg5 + ajg6 + S) during Ta1
  • Vcjg2 Vc. (+ ajg1 + ajg2-ajg3-ajg4-ajg5-ajg6 + S) during Ta2
  • Vcjg3 Vc.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Power Engineering (AREA)
  • Liquid Crystal (AREA)
  • Liquid Crystal Display Device Control (AREA)
  • Control Of Indicators Other Than Cathode Ray Tubes (AREA)
EP95401662A 1994-07-12 1995-07-10 Flüssigkristallanzeigeeinrichtung mit aktiver Matrix und unterteilter Gegenelektrode Withdrawn EP0692780A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9408644 1994-07-12
FR9408644A FR2722603B1 (fr) 1994-07-12 1994-07-12 Dispositif de visualisation a cristaux liquides, a matrice active et a contre-electrode fractionnee

Publications (1)

Publication Number Publication Date
EP0692780A1 true EP0692780A1 (de) 1996-01-17

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EP95401662A Withdrawn EP0692780A1 (de) 1994-07-12 1995-07-10 Flüssigkristallanzeigeeinrichtung mit aktiver Matrix und unterteilter Gegenelektrode

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Country Link
EP (1) EP0692780A1 (de)
JP (1) JPH0854603A (de)
CA (1) CA2153744A1 (de)
FR (1) FR2722603B1 (de)
TW (1) TW274607B (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0838801A1 (de) * 1996-10-22 1998-04-29 Hitachi, Ltd. Flüssigkristalltafel mit aktiver Matrix und Flüssigkristallanzeigeeinrichtung mit in Gruppen zerlegten gegenüberliegenden Elektroden
CN109754765A (zh) * 2017-11-06 2019-05-14 卡西欧计算机株式会社 电子装置、电子时钟、显示控制方法以及存储介质
WO2024022190A1 (zh) * 2022-07-26 2024-02-01 京东方科技集团股份有限公司 显示驱动方法、显示基板和显示装置

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI282539B (en) 2003-05-01 2007-06-11 Hannstar Display Corp A control circuit for a common line
US8508495B2 (en) * 2008-07-03 2013-08-13 Apple Inc. Display with dual-function capacitive elements

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3212863A1 (de) * 1981-04-07 1982-10-21 Kabushiki Kaisha Daini Seikosha, Tokyo Fluessigkristall-anzeigeeinrichtung
US4816819A (en) * 1984-11-26 1989-03-28 Canon Kabushiki Kaisha Display panel
EP0412757A2 (de) * 1989-08-07 1991-02-13 Sharp Kabushiki Kaisha Anzeigegerät

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3212863A1 (de) * 1981-04-07 1982-10-21 Kabushiki Kaisha Daini Seikosha, Tokyo Fluessigkristall-anzeigeeinrichtung
US4816819A (en) * 1984-11-26 1989-03-28 Canon Kabushiki Kaisha Display panel
EP0412757A2 (de) * 1989-08-07 1991-02-13 Sharp Kabushiki Kaisha Anzeigegerät

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
T.J.SCHEFFER ET AL.-: "Active Addressing of STN displays for high-performance video apllications", DISPLAYS, vol. 14, no. 2, GUILDFORD GB, pages 74 - 85 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0838801A1 (de) * 1996-10-22 1998-04-29 Hitachi, Ltd. Flüssigkristalltafel mit aktiver Matrix und Flüssigkristallanzeigeeinrichtung mit in Gruppen zerlegten gegenüberliegenden Elektroden
CN109754765A (zh) * 2017-11-06 2019-05-14 卡西欧计算机株式会社 电子装置、电子时钟、显示控制方法以及存储介质
CN109754765B (zh) * 2017-11-06 2021-08-24 卡西欧计算机株式会社 电子装置、电子时钟、显示控制方法以及存储介质
WO2024022190A1 (zh) * 2022-07-26 2024-02-01 京东方科技集团股份有限公司 显示驱动方法、显示基板和显示装置

Also Published As

Publication number Publication date
FR2722603A1 (fr) 1996-01-19
FR2722603B1 (fr) 1996-09-27
JPH0854603A (ja) 1996-02-27
TW274607B (de) 1996-04-21
CA2153744A1 (fr) 1996-01-13

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