EP0376233A2 - Système de commande pour un dispositif d'affichage - Google Patents

Système de commande pour un dispositif d'affichage Download PDF

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Publication number
EP0376233A2
EP0376233A2 EP89123913A EP89123913A EP0376233A2 EP 0376233 A2 EP0376233 A2 EP 0376233A2 EP 89123913 A EP89123913 A EP 89123913A EP 89123913 A EP89123913 A EP 89123913A EP 0376233 A2 EP0376233 A2 EP 0376233A2
Authority
EP
European Patent Office
Prior art keywords
voltage
column
drive means
driving
row
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.)
Granted
Application number
EP89123913A
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German (de)
English (en)
Other versions
EP0376233A3 (fr
EP0376233B1 (fr
Inventor
Kenichi C/O Seiko Instruments Inc. Kondo
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Seiko Instruments Inc
Original Assignee
Seiko Instruments Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from JP63334604A external-priority patent/JPH0782166B2/ja
Priority claimed from JP24101089A external-priority patent/JPH03102318A/ja
Application filed by Seiko Instruments Inc filed Critical Seiko Instruments Inc
Publication of EP0376233A2 publication Critical patent/EP0376233A2/fr
Publication of EP0376233A3 publication Critical patent/EP0376233A3/fr
Application granted granted Critical
Publication of EP0376233B1 publication Critical patent/EP0376233B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • G09G3/367—Control of matrices with row and column drivers with a nonlinear element in series with the liquid crystal cell, e.g. a diode, or M.I.M. element

Definitions

  • This invention relates to a driving method of a flat panel type display device with liquid crystal and the like.
  • this invention is applied to the driving method of an active panel device having non-linear resistance elements therein.
  • the active elements themselves have symmetrical characteristics relative to the supplying voltage in the plus direction or in the minus direction. Namely, they have asymmetric characteristics in general. For example, when the voltage VS. current characteristics in case of applying the plus directional voltage is compared to said characteristics in case of applying the minus directional voltage, they are different from each other to be asymmetrical.
  • voltage-averaging driving method is employed in the conventional matrix display device having liquid crystal.
  • dividing resistors 31, 32, 33, 34 and 35 are provided to divide an electric source voltage VDD and a liquid crystal driving voltage V LCD .
  • the divided voltages are amplified current by an operational amplifier circuit 40.
  • the operational amplifier circuit 40 outputs voltages V1, V2, V3 and V4 via resistors 36, 37, 38 and 39.
  • the electric source voltage V DD becomes the highest positive driving voltage V0.
  • the liquid crystal driving voltage V LCD becomes the lowest negative voltage V5.
  • the selected driving voltage V0 and V5 are inputted to a row electrode driving circuit and a column electrodes driving circuit.
  • the bias voltages V1 and V4 are inputted to the row electrode driving circuit, and V2 and V3 are inputted to the column electrode driving circuit.
  • the selected driving voltage V0 same magnitude of voltage is inputted to the row electrode driving circuit and the column electrode driving circuit.
  • the non-linearity of the active elements is asymmetrical, the amount of electric charge charged into the liquid crystal differs depending on the polarity voltage in the plus direction or in the minus direction, and the discharging time of said electric charge also differs.
  • Fig. 4 is a matrix diagram illustrating the structure of a matrix-type display device having non-linear active elements therein.
  • X1 ⁇ X2 are column electrododes
  • Y1 ⁇ Y2 are row electrododes
  • LA's are non-linear active elements
  • LC's are liquid crystal display dots at the cross points.
  • Fig. 5 shows the asymmetry of I-V characteristics of said non-linear active elements. As shown in the Fig. 5, when the case of supplying plus directional voltage to the non-linear active elements from the side of column electrodes is compared to the case of supplying minus directional voltage, it is necessary to make magnitude of the plus directional voltage larger in order to make flow same amount of current.
  • the liquid crystal Since the liquid crystal is displayed by means of holding the amount of electric charge charged by this current, it is important to make the plus directional voltage symmetrical with the minus directional voltage in case of driving the liquid crystal with non-­linear active elements.
  • the plus directional voltage and the minus directional voltage the magnitude thereof being mutually equal are applied to the non-linear active elements, it will be understood by the fact that holding time of the electric charge amount differs depending on the plus directional voltage and the minus directional voltage, because impedance in the plus direction is different from that in the minus direction.
  • object of the present invention is to provide a driving method for electrically compensating the asymmetry characteristics of the active elements.
  • Another object of the present invention is to provide a display device with high displaying quality.
  • a driving system which comprises column electrode driver for applying driving signals to column electrodes, row electrode driver for applying driving signals to row electrodes, and voltage generating circuit for providing driving voltage to the column electrode driver and the row electrode driver, and the driving voltage applied to the column electrode driver is not equal in absolute value to the driving voltage applied to the row electrode driver so as to compensate asymmetry characteristics between the plus direction and the minus direction of the non-linear active elements.
  • the voltage generating circuit comprises bias voltage generating circuit and selected voltage generating circuit, and the output voltage from the selected voltage generating circuit to the column electrode driver is not equal to the output voltage from the selected voltage generating circuit to the row electrode driver.
  • the selected voltage generating circuit comprises an adjusting means such as volume resistor which is capable of adjusting voltage at either one of the column electrodes and the row electrodes toward positive voltage or negative voltage.
  • Fig. 1 is a block diagram of the drive circuit for use in explaining driving method according to the present invention.
  • reference number 11 indicates the liquid crystal display panel.
  • Reference number 12 indicates a row electrode driver which outputs scan pules to each electrode.
  • Reference number 13 indicates a column electrode driver which converts video signals that arrive at each column in series into parallel signals and simultaneously outputs these to each column electrode.
  • Reference number 14 indicates a voltage generating circuit for providing driving voltage to the row electrode driver 12 and the column electrode driver 13. As shown in Fig. 1, the voltage generating circuit 14 comprises a bias voltage generating circuit 15 and a selected voltage generating circuit 16.
  • Fig. 2 is a circuit diagram illustrating one embodiment of a drive voltage generator circuit according to this invention.
  • 21, 22, 23, 24, and 25 are dividing resistors to divide voltage between electric source voltage V DD and liquid crystal drive voltage V LCD .
  • An operational amplifier circuit 222 amplifies the divided voltage to provide bias drive voltages V1, V2, V3 and V4.
  • Dividing resistors 210 and 211 divide voltage between electric source voltage V DD and liquid crystal driving voltage V LCD .
  • a variable resistor 212 divides voltage between V DD and V SS to output adjustable voltage.
  • An operational amplifier circuit 221 amplifies said divided voltage and adjustable voltage to output selected drive voltages V01 and V02 of positive polarity.
  • the selected drive voltage V01 of positive polarity is supplied to the column electrodes driving circuit, and the other selected drive voltage V02 is supplied to the row electrodes driving circuit, or vice versa.
  • the bias drive voltages V1, V4 and the selected drive voltage V5 of negative polarity are supplied to the row electrodes driving circuit.
  • the bias drive voltages V2, V3 and the selected drive voltage V5 of negative polarity are supplied to the column electrodes driving circuit.
  • magnitude of the other selected drive voltage V02 of positive polarity may be made to be larger or smaller than that of said selected drive voltage V01 of positive polarity by means of adjusting the variable resistor 212.
  • Fig. 6 is a diagram illustrating a drive voltage wave applied to liquid crystal elements in case that a conventional drive voltage generator circuit is drived by means of a conventional driving method.
  • Fig. 7 is a diagram illustrating a drive voltage wave with a drive voltage generator circuit according to this invention.
  • magnitude of the selected drive voltage of positive polarity is set to be larger than that of the selected drive voltage of negative polarity.
  • magnitude of the selected drive voltage of negative polarity larger than that of the selected drive voltage of positive polarity.
  • magnitude of the drive voltage of one polarity is made to be larger than that of the drive voltage of the other polarity in order to compensate the asymmetry of the active elements.
  • asymmetry of the active elements is adjusted to be symmetrical depending on magnitude of the drive voltages, and therefore, the amount of electrit charge charged into the liquid crystal display elements and the discharging time can be made to be equal irrespective of whether positive polarity or negative polarity.
  • asymmetry of active elements is able to be compensated by means of making magnitude of one side of selected drive voltage larger or smaller that that of the other side, even if the asymmetry of active elements is in the plus direction or in its reverse direction. Accordingly, the problems of striping phenomenon, charging-­up phenomenon and the like can be solved to provide a flat panel type display device with high displaying quality.
  • Fig. 8 illustrates a bias voltage generating circuit as modified embodiment of a drive system according to this invention.
  • Fig. 86 ⁇ 90 show resistors for dividing bias voltage.
  • 81 ⁇ 85 show operational amplifier circuits.
  • the value of V DD is + 5V
  • V LC is a negative voltage source for driving liquid crystals.
  • V01, V02 are respectively selected voltages in the plus direction for X electrode and for Y electrodode.
  • X electrode mean column electrode and Y electrode mean row electrode.
  • V5 shows a selected voltage in the minus direction.
  • V1 ⁇ V4 show bias voltage in case of not selected state.
  • each resistance value of resistors 86, 87, 89, 90 is 1.5R, 0.5R, 1.5R and 0.5R.
  • 86 is composed of a variable resistor, and its central point voltage is amplified by the operational amplifier circuit 81. Accordingly, it is understood that magnitude of the selected voltage v02 is the plus direction applied to said Y electrode is made lower than that of the selected voltage V01 in the plus direction applied to said X electrode.
  • bias voltage is not equally divided, but it is featured by being unequally divided.
  • said asymmetry of the non-linear active elements is compensated by this feature.
  • a conventional matrix-type display device with liquid crystal employs a drive bias circuit by means of voltage averaging method. That is, the portion between V DD and V LC is equally divided with resistors of mutually equal resistance so as to make the drive voltage applied in the plus direction of the liquid crystal to be equal to that applied in the minus direction thereof, whereby DC voltage is not applied to the liquid crystal.
  • Fig. 9 illustrates various driving waves for the embodiment of this invention.
  • the driving waves are illustrated the case of 1 dot-display and non-display being repeated at every line.
  • M is a polarity inverted signal at every frame
  • DFM shows a polarity inverted signal at every 2 lines.
  • Y1, X1 are respectively driving waves applied to row electrode and column electrode.
  • Y1 -X1 is a driving voltage wave to be applied to the liquid crystal at the cross point of Y1 -X1. As shown in Fig.
  • the driving wave between Y1 -X1 is wholly shifted to the side of column electrode, and the minus directional voltage is applied to the plus directional voltage at the side of column electrode so that larger voltage can be applied to the side of column electrode. Accordingly, larger voltage is applied to the side of column electrode in order to compensate the asymmetry of said non-linear active elements, and thus same amount of charging current can be supplied for the voltage driving operation both in the plus direction and in the minus direction, thereby the compensating operation become capable to hole the same charged electric charge.
  • the asymmetry of non-linear active elements is compensated by the drive voltage. Accordingly, the problem of striping phenomenon as the conventional problem could be solved by means of obtaining uniform going down time by changing said resistance values and by adjusting the variable resistance value. Said problem was presented as follows: while the display operation is performed by the drive voltage in the plus direction or in the minus direction, the time difference (about 2 - 10 ms) of going down response in case of the non-display phenomenon being occurred is the cause of said problem of striping phenomenon. And also, the problem of charging-up could be solved. Said problem was presented as follows: because of over stored electric charge, the off-­time is lengthened and the display state is continued for a relatively long time. Furthermore, since the liquid crystal at the cross points of X abscissa and Y ordinate is substantially AC driven without having DC component, life of the liquid crystal may be lengthened compared to the conventional 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 Display Device Control (AREA)
  • Liquid Crystal (AREA)
EP89123913A 1988-12-29 1989-12-25 Système de commande pour un dispositif d'affichage Expired - Lifetime EP0376233B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP334604/88 1988-12-29
JP63334604A JPH0782166B2 (ja) 1988-12-29 1988-12-29 液晶表示装置
JP24101089A JPH03102318A (ja) 1989-09-18 1989-09-18 表示装置の駆動方法
JP241010/89 1989-09-18

Publications (3)

Publication Number Publication Date
EP0376233A2 true EP0376233A2 (fr) 1990-07-04
EP0376233A3 EP0376233A3 (fr) 1991-09-11
EP0376233B1 EP0376233B1 (fr) 1996-03-20

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP89123913A Expired - Lifetime EP0376233B1 (fr) 1988-12-29 1989-12-25 Système de commande pour un dispositif d'affichage

Country Status (2)

Country Link
EP (1) EP0376233B1 (fr)
DE (1) DE68926032T2 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0523796A1 (fr) * 1991-07-17 1993-01-20 Philips Electronics Uk Limited Dispositif d'affichage à matrice active et sa méthode de fonctionnement
EP0619572A1 (fr) * 1993-04-08 1994-10-12 Citizen Watch Co., Ltd. Mèthode de commande d'un panneau d'affichage à cristaux liquides
US5561441A (en) * 1993-04-08 1996-10-01 Citizen Watch Co., Ltd. Liquid crystal display device
US8492374B2 (en) 2009-04-29 2013-07-23 Industrial Technology Research Institute Azaazulene compounds

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0199361A2 (fr) * 1985-04-26 1986-10-29 Matsushita Electric Industrial Co., Ltd. Circuit de commande pour un dispositif d'affichage à cristaux liquides
EP0278778A2 (fr) * 1987-02-13 1988-08-17 Seiko Instruments Inc. Dispositif d'affichage à matrice active du type non linéaire à deux bornes
EP0285401A2 (fr) * 1987-03-31 1988-10-05 Canon Kabushiki Kaisha Dispositif d'affichage

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0199361A2 (fr) * 1985-04-26 1986-10-29 Matsushita Electric Industrial Co., Ltd. Circuit de commande pour un dispositif d'affichage à cristaux liquides
EP0278778A2 (fr) * 1987-02-13 1988-08-17 Seiko Instruments Inc. Dispositif d'affichage à matrice active du type non linéaire à deux bornes
EP0285401A2 (fr) * 1987-03-31 1988-10-05 Canon Kabushiki Kaisha Dispositif d'affichage

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0523796A1 (fr) * 1991-07-17 1993-01-20 Philips Electronics Uk Limited Dispositif d'affichage à matrice active et sa méthode de fonctionnement
US5892504A (en) * 1991-07-17 1999-04-06 U.S. Philips Corporation Matrix display device and its method of operation
EP0619572A1 (fr) * 1993-04-08 1994-10-12 Citizen Watch Co., Ltd. Mèthode de commande d'un panneau d'affichage à cristaux liquides
US5561441A (en) * 1993-04-08 1996-10-01 Citizen Watch Co., Ltd. Liquid crystal display device
US8492374B2 (en) 2009-04-29 2013-07-23 Industrial Technology Research Institute Azaazulene compounds

Also Published As

Publication number Publication date
DE68926032D1 (de) 1996-04-25
EP0376233A3 (fr) 1991-09-11
DE68926032T2 (de) 1996-09-05
EP0376233B1 (fr) 1996-03-20

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