EP0120732B1 - Verfahren zur sequentiellen Steuerung einer Flüssigkristall-Matrixanzeigeeinrichtung unter Benutzung des cholesterisch-nematischen Phasenübergangs - Google Patents

Verfahren zur sequentiellen Steuerung einer Flüssigkristall-Matrixanzeigeeinrichtung unter Benutzung des cholesterisch-nematischen Phasenübergangs Download PDF

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Publication number
EP0120732B1
EP0120732B1 EP84400320A EP84400320A EP0120732B1 EP 0120732 B1 EP0120732 B1 EP 0120732B1 EP 84400320 A EP84400320 A EP 84400320A EP 84400320 A EP84400320 A EP 84400320A EP 0120732 B1 EP0120732 B1 EP 0120732B1
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Prior art keywords
potential
liquid crystal
threshold voltage
time
column
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Expired
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EP84400320A
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English (en)
French (fr)
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EP0120732A1 (de
Inventor
Jean Frédéric Clerc
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Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
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Commissariat a lEnergie Atomique CEA
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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
    • G09G3/3622—Control of matrices with row and column drivers using a passive matrix
    • G09G3/3629—Control of matrices with row and column drivers using a passive matrix using liquid crystals having memory effects, e.g. ferroelectric liquid crystals
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2300/00—Aspects of the constitution of display devices
    • G09G2300/04—Structural and physical details of display devices
    • G09G2300/0469—Details of the physics of pixel operation
    • G09G2300/0478—Details of the physics of pixel operation related to liquid crystal pixels
    • G09G2300/0482—Use of memory effects in nematic liquid crystals
    • G09G2300/0486—Cholesteric liquid crystals, including chiral-nematic liquid crystals, with transitions between focal conic, planar, and homeotropic states
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00—Command of the display device
    • G09G2310/06—Details of flat display driving waveforms
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2310/00—Command of the display device
    • G09G2310/06—Details of flat display driving waveforms
    • G09G2310/061—Details of flat display driving waveforms for resetting or blanking

Definitions

  • the present invention relates to a method for sequential control of a matrix imager using the cholesteric-nematic phase transition effect of a liquid cirstal. It finds an application in the production of liquid crystal display devices used in particular in the binary display of complex images or in the display of alphanumeric characters.
  • the invention relates to the control of a matrix imager comprising a display cell constituted by two transparent insulating walls and by a liquid crystal comprising zones distributed in a matrix and interspersed in a system known as crossed bands or in English terminology in a “cross bar” system.
  • FIG. 1 there is shown such a matrix imager.
  • This comprises a display cell which has two walls 10 and 12, generally transparent, arranged on either side of a shim 14 of thickness, made of insulating material, defining a volume 16 which is occupied, when the cell is mounted, by a liquid crystal film.
  • On the walls 10 and 12 are deposited two systems of electrodes each constituted by a series of parallel semi-transparent conductive strips; the rows of electrodes for example the number of p are denoted x ;, where i is an integer which can take all the values between 1 and p, and the columns of electrodes, for example the number of a are denoted y j , where j is an integer which can take all values between 1 and g.
  • the useful surface of the liquid crystal is thus broken down into a mosaic of zones corresponding to the overlapping zones of the two electrode systems, each zone corresponding to the overlapping of two strips x i and y j and which can therefore be identified by the notation x i y j .
  • the rows and columns of electrodes are capable of conveying electrical signals suitable for the excitation of the liquid crystal which has an optical property dependent on this excitation.
  • the sensitization of an area of the liquid crystal is carried out by applying to the electrodes x; and y i electrical voltages which cause the appearance of an electric field within the liquid crystal.
  • This electric field acts on the cholesteric-nematic phase transition of the liquid crystal.
  • the liquid crystal has two threshold voltages, a low threshold voltage V B and a high threshold voltage V H such that 0 ⁇ V B ⁇ V H.
  • the application of a potential difference between the lines x i and the columns y j , or control voltage, which is greater than the high threshold voltage V H makes it possible to obtain the liquid crystal in the nematic form and l application of a potential difference between the lines x i and the columns y j , which is less than the low threshold voltage V B , makes it possible to obtain the liquid crystal in the cholesteric form and this, whatever the phase previous liquid crystal.
  • nematic phase for an area x i y j of the liquid crystal corresponds to the display of this area, the latter becoming white in the presence of a dichroic dye, and obtaining the cholesteric phase for this same zone corresponds to the non-displayed state of said zone, the latter then appearing black due to the dichroism of the dye.
  • this type of display cell has a certain memory effect. Indeed, after having obtained the displayed state of the zone x i y j , the application of a potential difference between the line x i and the column y j between the voltages V B and V H is sufficient to maintain l displayed state of this zone. Similarly, after having obtained the not displayed state of the area x i y j , the application of a potential difference between the row x i and the column y (between the voltages V B and V H ) is sufficient to maintain the non-displayed state of said zone.
  • these holding voltages from the displayed or not displayed state, are necessary to keep a good contrast between the displayed zones, or white dots and the non-displayed zones, or black dots; the absence of these holding voltages results in a significant reduction in said contrast.
  • FIG. 2a the potential difference between the line x i and the column y i , or control voltage V c , has been represented as a function of time and in FIG. 2b the response curve of the liquid crystal as a function of the value of the potential difference V c , this response curve corresponding to the light intensity (I) transmitted by the area x i y j as a function of time.
  • the steps 20 and 22 of the cell response curve correspond to the non-displayed state of the area x i y j ; the level 24 of this same curve corresponds to the displayed state of said zone and the rising and falling parts respectively 26 and 28 of said curve correspond to the cholesteric-nematic and nematic-cholesteric phase change respectively of the liquid crystal and therefore to the passage of the state not displayed in the displayed state and vice versa.
  • the sensitization of the zone x i y j of the liquid crystal is carried out by sending to the line x i , for a time t 1 equal to r ⁇ , where r is an integer and ⁇ an elementary interval of time useful for the command, an electrical erasure signal, of amplitude much greater than the high threshold voltage V H of the liquid crystal followed by an electrical signal for addressing said line, for a time t 2 equal to ⁇ .
  • the integer r depends on the speed of transition between its two phases of the liquid crystal used. Its value is a few general units ment 1, 2 or 3.
  • the time r in fact corresponds to the minimum time necessary for the change of nematic-cholesteric phase of the liquid crystal (passage from the nematic phase to the cholesteric phase).
  • an electrical addressing signal is applied to column y j , in particular an alternating signal with zero mean value having an effective value generally equal to that of the addressing signal of line x i , this signal being during time addressing t 2 of line x i either in phase or in phase opposition, with the addressing signal of said line.
  • FIGS. 3b and 3c show, as a function of time, the addressing signal of the column y j , respectively, in phase and in phase opposition with the addressing signal of the line x i , V b corresponding to the RMS voltage of said signals.
  • the p lines are controlled successively and the g columns simultaneously in order to cause an image, or an alpha-numeric character, defined point by point, to appear on said imager.
  • the response curves of the zone x i y j of the liquid crystal have been represented as a function of the previous sensitizations. These curves give the light intensity transmitted (I) by the liquid crystal zone as a function of time.
  • the rising part 30 of the two curves O and P corresponds to the change of cholesteric-nematic phase of the liquid crystal (passage from the cholesteric phase to the nematic phase), this phase change taking place during the erasure period t l . It should be noted that the time to obtain this phase transition being relatively long, it is necessary to carry out the latter during the erasing period t 1 of the line x i .
  • the level 32 of the curve 0 corresponds to the displayed state of the area x i y j , obtained when the signals applied to the line x i and the column y j are in phase opposition
  • the level 34 of the curve P corresponds to the non-displayed state of the zone x i y j , obtained when phase x signals are applied to the line x i and the column y j
  • the descending part 34a of the curve P corresponds to the change in nematic-cholesteric phase of the liquid crystal.
  • the subject of the present invention is precisely a method of sequential control of a matrix imager using the cholesteric-nematic phase transition effect of a liquid crystal making it possible in particular to suppress the movement of such a white line on said imager.
  • the awareness of a zone x i y j is done by reversing the role of the rows and columns of electrodes, which allows, when sensitizing the p zones of the liquid crystal of the same column y j , by applying the potential V 3 simultaneously on the p rows of electrodes , to suppress the scrolling of the white line on the imager.
  • the sum V 4 + V5 is greater than the high threshold voltage V H to refresh during the scanning of the line the displayed state.
  • the potentials V 2 and V 3 are equal.
  • the different potentials V 1 , V 2 , V 3 , V 4 and V 5 are alternating potentials with zero mean values, V 1 , V 2 , V 3 , V 4 and V5 then representing the effective values of these potentials.
  • a first potential V 1 is applied to the column y j (FIG. 1). a voltage much higher than the high threshold voltage V H of the liquid crystal.
  • This first potential corresponds to the erasure signal relating to the area x i y j .
  • This erasure signal is applied, as for the prior art, before the actual addressing of the zone x i y j , in order to allow the passage from the cholesteric phase to the nematic phase of the liquid crystal.
  • This signal is applied for a time t 1 1 equal to s ⁇ , s being an integer which depends on the speed of transition between its two phases of the liquid crystal used and ⁇ the minimum time necessary for the transition from the nematic phase to the cholesteric phase.
  • this erasure signal is an alternating signal with zero mean value, for example a rectangular signal, for which V 1 represents the effective value of said signal.
  • This signal is in particular that which is represented on part 29 of the signal of FIG. 3a.
  • a second potential V 2 is applied to said column y i corresponding to the address signal of the column.
  • This addressing signal is applied for a time t 2 equal to ⁇ .
  • this addressing signal of column y j is an alternating signal with zero mean value, for example a rectangular signal, for which V 2 represents the effective value of said signal.
  • This signal is in particular that which is represented on the part 31 of the signal of FIG. 3a.
  • a third potential V 3 corresponding to the line addressing signal is preferably an alternating signal with zero mean value, for example a rectangular signal, for which V 3 represents the effective value of said signal.
  • This signal is in particular that shown in FIG. 3b or in FIG. 3c.
  • the sum of the potentials V 2 + V 3 at the terminals of the liquid crystal, or control voltage, during the time t 2 for addressing the column y j must have a value greater than the high threshold voltage V H of the liquid crystal to obtain the displayed state of the area x i y j , in other words a white point on the imager.
  • the potential difference V Z- V 3 during time t 2 , must have a value lower than the low threshold voltage V B of the liquid crystal in order to obtain the non-displayed state of the zone x i y j , in other words a black dot on the imager.
  • the two potentials V 2 and V 3 are equal.
  • obtaining the non-displayed state is done by using, during time t 2 , row and column signals in phase, such as those represented in FIGS. 3a and 3b.
  • V 2 and V 3 equal to the value V o
  • V 2 -V 3 a potential difference V 2 -V 3 equal to 0 is obtained.
  • the columns of the imager not selected are brought to a zero continuous potential, for example the potential of the mass.
  • the columns are controlled successively while the rows are controlled simultaneously. Furthermore, the display or not of an entire column of the imager is done by sensitizing, as described above, the p zones of said column by simultaneously applying to each line the potential V 3 .
  • liquid crystals with a cholesteric-nematic phase transition exhibit a memory effect, that is to say that after having deleted the electrical control signal, the displayed or white points of the imager remain displayed. It is the same for the not displayed or black points.
  • the contrast of these points decreasing over time, it is therefore necessary to maintain a certain voltage across the terminals of the corresponding zone x i y j to avoid too great a loss of contrast.
  • a zero potential is applied to the line x i , for the time t 1 , that is to say without an erasure signal, and during time t 2 a fourth potential V 4 corresponding to the line addressing signal. Furthermore, a fifth potential V5 is applied to the column y corresponding to the column addressing signal.
  • the row and column addressing signals are alternating signals with zero mean value, for example rectangular, for which V 4 and V5 respectively represent the effective values of said signals.
  • the addressing signal of the line x i is represented , as a function of time, Va corresponding to the effective voltage of said row signal
  • the addressing signal of the column y i is represented , as a function of time, V b corresponding to the RMS voltage of the column signal.
  • the sum of the potentials V 4 + V5 at the terminals of the liquid crystal, during the addressing time t 2 must have a value greater than the low threshold voltage V B of the liquid crystal to maintain the displayed state of the area x i y j (white point).
  • the potential difference V 4 -V5, during time t 2 must have a value lower than the high threshold voltage V H of the liquid crystal in order to maintain the non-displayed state of the zone x i y j (point black).
  • the sum of the potentials V 4 + V5, for maintaining the displayed state is greater than the high threshold voltage V H of the liquid crystal. This improves the contrast between the zones in the displayed state (white dots) and the zones in the non-displayed state (black dots).
  • the potential V 4 is chosen so as to be equal to twice the potential V5 to avoid any change in appearance during the scanning of the line.
  • FIG. 5c the voltage V c applied to the terminals of the liquid crystal is shown, the signal 38, in solid line being obtained when the row and column signals are in phase opposition.
  • the maintenance of the non-displayed state is done by using, for the time t 2 , row and column signals in phase, like the signal in FIG. 5a and the signal 40, in dotted lines, of Figure 5b.
  • a potential V5 equal to V o a potential difference V 4 -V5 is obtained, or control voltage V, equal to V o , V o being chosen so as to be less than the high threshold voltage V H of the crystal liquid.
  • the signal 42 in dotted lines, in FIG. 5c, represents the voltage V c applied to the terminals of the crystal, when the row and column signals are in phase.
  • the lines are controlled successively. Furthermore the maintenance of the state displayed or not displayed of a whole line of the matrix imager, that is to say q zones of said line, is done by applying simultaneously to each column the potential V5.
  • the values of the threshold voltages are of the order of a few volts. Typically, the low threshold voltage V B is equal to 5V and the high threshold voltage V H is equal to 10V.
  • the liquid crystals used having a cholesteric-nematic phase transition, consist of a mixture of three components: a nematic component, a cholesteric component and a dye.
  • nematic components such as components E7 and E43 from the company MERCK, esters, Schiff bases and phenylcyclohexanes.
  • the cholesteric component can in particular be a mixture of CB15 produced by the company B.d.h and ZL811 produced by the company MERCK in proportions such that the pitch varies little with temperature.
  • anthraquinons such as components D5 and D16 from the company B.d.h are dyes commonly used by those skilled in the art.

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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)
  • Liquid Crystal (AREA)
  • Liquid Crystal Display Device Control (AREA)

Claims (9)

1. Verfahren zur sequentiellen Steuerung einer Flüssigkristallmatrix-Anzeigeeinrichtung unter Ausnützung des kolesterisch-nematischen Phasenübergangs eines Flüssigkristalls, der in Form einer Matrix verteilte Bereiche aufweist und der zwischen einer ersten Gruppe von p parallelen Zeilenelektroden und einer zweiten Gruppe von q parallelen Spaltenelektroden angeordnet ist, wobei die Zeilen und Spalten gekreuzt sind, wodurch ein Bereich xiyj durch den Teil des Flüssigkristalls definiert wird, der von der Zeile x; mit i einer ganzen Zahl und 1 ≤ i ≤ p und durch die Spalte yj mit j einer ganzen Zahl und 1 ≤ j ≤ q bedeckt wird, wobei die Zeilen und Spalten dazu dienen, elektrische Signale zu transportieren, die auf den Phasenübergang des Flüssigkristalls einwirken, wobei eine der beiden Phasen dem Anzeige-Zustand entspricht und die andere dem Nichtanzeige-Zustand und wobei der Flüssigkristall eine niedere Schwellenspannung VB und eine hohe Schwellenspannung VH aufweist, dadurch gekennzeichnet, dass:
- zum Erhalten eines der beiden Zustände im Bereich xiyj an die Spalte yi während eines Zeitintervalls t1 gleich sτ, mit s einer ganzen Zahl und τ dem Zeitintervall, das zur Steuerung verwendet wird, ein erstes Potential V1 angelegt wird, das einen Wert hat, der grösser als die hohe Schwellenspannung VH ist, gefolgt von einem zweiten Potential V2, das an der Spalte während eines Zeitintervalls t2 angelegt wird, wobei t2 gleich τ ist und die anderen Spalten auf Nullpotential liegen und an die Zeile xi ein drittes Potential V3 angelegt wird, wobei die Potentiale V2 und V3 während der Zeit t2 Phasen und Werte aufweisen derart, dass die Summe V2 + V3 grösser als die hohe Schwellenspannung VH ist, um den Anzeige-Zustand zu erreichen und die Differenz V2-V3 kleiner als die niedrige Schwellenspannung VB ist, um den Nichtanzeige-Zustand zu erhalten und dadurch, dass
- zum Beibehalten des Zustands des Bereiches xiyj an die Zeile xi während des Zeitintervalls t1 ein Nullpotential angelegt wird und während des Zeitintervalls t2 ein viertes Potential V4, wobei an den anderen Zeilen ein Nullpotential anliegt und an die Spalte yj ein fünftes Potential V5 angelegt wird, wobei die Potentiale V4 und V5 während des Zeitintervalls t2 Phasen und Werte aufweisen derart, dass die Summe V4 + V5 grösser als die niedrige Schwellenspannung VB ist, um den Anzeige-Zustand zu erhalten und die Differenz V4-V5 kleiner als die hohe Schwellenspannung VH ist, um den nicht angezeigten Zustand zu erhalten.
2. Steuerverfahren nachAnspruch 1, dadurch gekennzeichnet, dass die Summe V4 + V5 grösser als die hohe Schwellenspannung VH zum Beibehalten des Anzeige-Zustands ist.
3. Steuerverfahren nach einem der Ansprüche 1 und 2, dadurch gekennzeichnet, dass das Potential V2 gleich dem Potential V3 ist.
4. Steuerverfahren nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass das Potential V4 doppelt so gross wie das Potential V5 ist.
5. Steuerverfahren nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, dass die verschiedenen Potentiale V1, V2, V3, V4 und V5 Wechselspannungen mit dem Mittelwert 0 sind, die Potentiale V1 bis V5 also die Effektivspannungen dieser Potentiale darstellen.
6. Steuerverfahren nach Anspruch 5, dadurch gekennzeichnet, dass die Potentiale Rechteckpotentiale sind.
7. Steuerverfahren nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, dass das Potential V3 gleichzeitig an die p Zeilenelektroden angelegt wird, um einen der beiden Zustände der p Bereiche einer selben Spalte (yi) zu erhalten.
8. Steuerverfahren nach einem der Ansprüche 1 bis 7, dadurch gekennzeichnet, dass das Potential V5 gleichzeitig an die q Spaltenelektroden angelegt wird, um den Zustand der q Bereiche einer selben Zeile x; zu halten.
EP84400320A 1983-02-24 1984-02-16 Verfahren zur sequentiellen Steuerung einer Flüssigkristall-Matrixanzeigeeinrichtung unter Benutzung des cholesterisch-nematischen Phasenübergangs Expired EP0120732B1 (de)

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Application Number Priority Date Filing Date Title
FR8303047 1983-02-24
FR8303047A FR2541807B1 (fr) 1983-02-24 1983-02-24 Procede de commande sequentielle d'un imageur matriciel utilisant l'effet de transition de phase cholesterique-nematique d'un cristal liquide

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EP0120732A1 EP0120732A1 (de) 1984-10-03
EP0120732B1 true EP0120732B1 (de) 1987-06-03

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US (1) US4625204A (de)
EP (1) EP0120732B1 (de)
JP (1) JPS59164597A (de)
CA (1) CA1231187A (de)
DE (1) DE3464098D1 (de)
FR (1) FR2541807B1 (de)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2558606B1 (fr) * 1984-01-23 1993-11-05 Canon Kk Procede de commande d'un dispositif de modulation optique et dispositif de modulation optique pour sa mise en oeuvre
US5757350A (en) * 1984-01-23 1998-05-26 Canon Kabushiki Kaisha Driving method for optical modulation device
US5296953A (en) * 1984-01-23 1994-03-22 Canon Kabushiki Kaisha Driving method for ferro-electric liquid crystal optical modulation device
JPS61156229A (ja) * 1984-12-28 1986-07-15 Canon Inc 液晶装置
GB2173335B (en) * 1985-04-03 1988-02-17 Stc Plc Addressing liquid crystal cells
GB2173336B (en) * 1985-04-03 1988-04-27 Stc Plc Addressing liquid crystal cells
SE8504760D0 (sv) * 1985-10-14 1985-10-14 Sven Torbjorn Lagerwall Electronic addressing of ferroelectric liquid crystal devices
US5255110A (en) * 1985-12-25 1993-10-19 Canon Kabushiki Kaisha Driving method for optical modulation device using ferroelectric liquid crystal
GB2185614B (en) * 1985-12-25 1990-04-18 Canon Kk Optical modulation device
GB2207272B (en) * 1987-07-18 1991-08-14 Stc Plc Addressing liquid crystal cells
GB8726996D0 (en) * 1987-11-18 1987-12-23 Secr Defence Multiplex addressing of ferro-electric liquid crystal displays
FR2627308B1 (fr) * 1988-02-15 1990-06-01 Commissariat Energie Atomique Procede de commande d'un ecran d'affichage matriciel permettant d'ajuster son contraste et dispositif pour la mise en oeuvre de ce procede
US5424753A (en) * 1990-12-31 1995-06-13 Casio Computer Co., Ltd. Method of driving liquid-crystal display elements
JPH05127616A (ja) * 1991-10-31 1993-05-25 Canon Inc 電気光学表示装置および電気光学素子駆動装置

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4041481A (en) * 1974-10-05 1977-08-09 Matsushita Electric Industrial Co., Ltd. Scanning apparatus for an electrophoretic matrix display panel
GB1502280A (en) * 1974-12-11 1978-03-01 Secr Defence Liquid crystal displays
JPS53995A (en) * 1976-06-25 1978-01-07 Toshiba Corp Driving system for matrix of storage type liquid crystal element
GB2004679B (en) * 1977-09-26 1982-03-03 Secr Defence Matrix addressing liquid crystal display
JPS5476095A (en) * 1977-11-30 1979-06-18 Toshiba Corp Matrix drive system of storage type liquid crystal element
US4380008A (en) * 1978-09-29 1983-04-12 Hitachi, Ltd. Method of driving a matrix type phase transition liquid crystal display device to obtain a holding effect and improved response time for the erasing operation
JPS5576393A (en) * 1978-12-04 1980-06-09 Hitachi Ltd Matrix drive method for guestthostttype phase transfer liquid crystal
US4529271A (en) * 1982-03-12 1985-07-16 At&T Bell Laboratories Matrix addressed bistable liquid crystal display
JPH0629919B2 (ja) * 1982-04-16 1994-04-20 株式会社日立製作所 液晶素子の駆動方法

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US4625204A (en) 1986-11-25
CA1231187A (en) 1988-01-05
FR2541807A1 (fr) 1984-08-31
FR2541807B1 (fr) 1985-06-07
DE3464098D1 (en) 1987-07-09
EP0120732A1 (de) 1984-10-03
JPS59164597A (ja) 1984-09-17

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