EP0631394A1 - Flüssigkristallanzeigevorrichtung - Google Patents

Flüssigkristallanzeigevorrichtung Download PDF

Info

Publication number
EP0631394A1
EP0631394A1 EP94304204A EP94304204A EP0631394A1 EP 0631394 A1 EP0631394 A1 EP 0631394A1 EP 94304204 A EP94304204 A EP 94304204A EP 94304204 A EP94304204 A EP 94304204A EP 0631394 A1 EP0631394 A1 EP 0631394A1
Authority
EP
European Patent Office
Prior art keywords
switches
data
data line
bits
liquid crystal
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.)
Ceased
Application number
EP94304204A
Other languages
English (en)
French (fr)
Inventor
Hiroshi Suzuki
Midori Suzuki
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.)
International Business Machines Corp
Original Assignee
International Business Machines Corp
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
Application filed by International Business Machines Corp filed Critical International Business Machines Corp
Publication of EP0631394A1 publication Critical patent/EP0631394A1/de
Ceased legal-status Critical Current

Links

Images

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
    • G09G3/3685—Details of drivers for data electrodes
    • G09G3/3688—Details of drivers for data electrodes suitable for active matrices only
    • 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
    • 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
    • G09G3/3696—Generation of voltages supplied to electrode drivers
    • 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
    • G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
    • G09G2310/0243—Details of the generation of driving signals
    • G09G2310/0248—Precharge or discharge of column electrodes before or after applying exact column voltages
    • 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
    • G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
    • G09G2310/0264—Details of driving circuits
    • G09G2310/027—Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/06—Adjustment of display parameters
    • G09G2320/066—Adjustment of display parameters for control of contrast
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/2007—Display of intermediate tones
    • G09G3/2011—Display of intermediate tones by amplitude modulation
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/2007—Display of intermediate tones
    • G09G3/2014—Display of intermediate tones by modulation of the duration of a single pulse during which the logic level remains constant

Definitions

  • the present invention relates to a liquid crystal display apparatus including a driver for driving data lines of the liquid crystal display panel.
  • TFT/LCD thin-film transistor liquid crystal displays
  • analog type driver an analog data signal representing gradations of respective pixels is sampled and held using switches and capacitors, buffered in operational amplifiers (voltage followers) and then output to data lines of a display panel.
  • the analog type driver can produce continuous (i.e., infinite) gradations.
  • there are various problems such as low accuracy of output voltages, low operation speed and large power consumption, and thus the analog type driver is rarely used for computer displays.
  • the digital type driver a plurality of power supplies having different potentials are connected to each data line through their respective switches and a voltage signal is supplied to each data line by selectively turning on one of the switches in accordance with the input data. Since no linear circuit is used, the digital type driver consumes little power. Furthermore, since the power supply voltages are output as they are, output voltages are highly accurate and the operation speed can easily be increased. However, to increase display gradations, it is necessary to increase the number of power supply terminals to provide potentials corresponding to the respective necessary gradations and the number of switches corresponding to the respective power supply terminals.
  • Japanese patent application PEPA No. 61-58008 published on December 9, 1986 discloses a voltage generation circuit for producing a plurality of differing voltage outputs from a pair of power supplies in the above type of driver.
  • a plurality of intermediate voltages between the voltages of the pair of power supplies are generated by dividing the interval between the two power supply voltages using a plurality of resistors based on the operation of selection switches. By connecting capacitors at positions where the voltage difference across the terminals of the division resistor is constant, the problem of the output waveform distortion is solved without increasing the power consumption.
  • an object of the present invention is to provide a liquid crystal display apparatus which can perform multi-gradation display without increasing the chip area of the driver, i.e., with a smaller number of circuit elements.
  • the present invention provides a liquid crystal display apparatus comprising a liquid crystal display panel having a plurality of display cells arranged in a matrix and a plurality of data lines connected to the display cells, means for receiving input data comprising a plurality of bits per pixel, said plurality of bits representing gradations of a pixel to be displayed on the panel, and a drive means for driving the data lines by potential signals corresponding to the respective gradations represented by the input data, the drive means comprising: at least two switches connected to a power supply for selectively supplying reference potentials corresponding to at least two different graduation values to the data line; and decoding means responsive to the input data to control said two switches so that the switches are alternately turned on and off at a predetermined cycle so as to supply a potential to said data line, obtained from said reference potential, corresponding to a gradation represented by the input data.
  • switches are connected to respective power supplies having reference potentials corresponding to at least two different gradations to allow the reference potentials to be selectively supplied to a data line of the liquid crystal display panel through the switches.
  • a decoder is provided which decodes input data and controls the switches so that the switches are alternately turned on and off at a predetermined cycle at a ratio in which the reference potentials are proportionally divided by a potential corresponding to a gradation represented by the input data.
  • multiple graduations can be obtained by means of a driver which needs only two switches to produce the output voltage having an arbitrary level between two potentials. A small chip area is thus achieved.
  • FIG. 1 is a block diagram schematically showing a multi-gradation thin-film transistor liquid crystal display (TFT/LCD) according to the present invention.
  • this type of display consists of a shift register 1 for converting, to parallel data, serial input data (which represents display gradations of respective pixels) of a line to be displayed that is received from a data source such as the CPU of a computer, a latch circuit 2 for latching the parallel-converted input data, a driver 5 for driving data lines 4 of a thin-film transistor liquid crystal display 3 by output potentials having magnitudes corresponding to the respective input data of the latch circuit 2, and a scanning circuit (gate driver) 7 for sequentially supplying scanning signals to gate lines 6 of the display panel 3.
  • Each display cell on the gate line 6 being driven by the scanning circuit 7 exhibits gradations corresponding to the output potential of the associated data line.
  • the input data represents gradations of the respective pixels of one line.
  • the input data consists of 6 bits per pixel. Therefore, the driver 5 should be able to generate potentials of 64 different magnitudes to properly represent the 6-bit gradation data.
  • FIG. 2 is a schematic circuit diagram which shows a driver circuit embodying the principle of the invention. Switches connected to two respective power sources supplying the terminals of a driver IC having different potentials are turned on and off at a predetermined cycle at a time ratio in which the two potentials are proportionally divided by a potential corresponding to a gradation represented by the input data, so that the output potential necessary to produce the gradation represented by the input data is supplied to the cell.
  • the potentials of the two power supply terminals are denoted by V a and V b
  • the switches connected to the respective terminals are denoted by SW a and SW b
  • a load resistance and a capacitance of the data line of the display panel are denoted by R and C
  • the output potential given to the cell is denoted by V c .
  • the time necessary to charge up the resistor and the capacitor of the data line is denoted by T
  • on-periods of the respective switches SW a and SW b in a predetermined cycle t are denoted by t a and t b , where t « T.
  • the output potential V c changes as shown in Figure 4 because of the existence of an RC circuit consisting of the load resistor and the capacitor of the data line, and settles after a lapse of time period T.
  • T and t are longer than about 30 ⁇ sec. and 3 ⁇ sec., respectively.
  • V a and V b are 5 V and 4 V, respectively and the time ratio t a /t b is an integer-to-integer ratio from 6:0 to 0:6, the output voltage V c takes values listed in the following table, as derived from Eq. 1.
  • FIG 5 schematically shows an embodiment of an invention for driving one data line in the driver 5 (see Figure 1).
  • the driver 5 has this type of circuit in the number of data lines 4.
  • the driver 5 includes a plurality of switches SW1-SW17 that are connected to respective power supply terminals having a plurality of potentials V1-V17 (e.g., 1 to 17 V), and is constructed so as to selectively supply the potentials of the respective terminals to the data line 4.
  • the upper 4-bit data is input to a first decoder 11 and the lower 2-bit data is input to a second decoder 12.
  • the first decoder 11 converts the upper 4-bit data to a signal for selecting one switch SW i and the following switch SW i+1 from the switches SW1-SW17.
  • the second decoder 12 converts the lower 2-bit data into a signal indicating the ratio (time ratio) between the on-periods t a and t b of the respective selected switches SW i and SW i+1 .
  • the switches SW i and SW i+1 are turned on and off at a predetermined cycle (e.g., 3 ⁇ sec.) at the time ratio indicated by the output signal of the decoder 12. After this operation is repeated for the predetermined period (e.g., 30 ⁇ sec.) necessary to charge up the data line, the output potential to be applied to the cell settles, as described above, to the potential corresponding to the 6-bit gradation data.
  • the output potential takes a value corresponding to the gradation data.
EP94304204A 1993-06-24 1994-06-10 Flüssigkristallanzeigevorrichtung Ceased EP0631394A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP153823/93 1993-06-24
JP15382393A JPH0720821A (ja) 1993-06-24 1993-06-24 多階調薄膜トランジスタ液晶表示装置

Publications (1)

Publication Number Publication Date
EP0631394A1 true EP0631394A1 (de) 1994-12-28

Family

ID=15570875

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94304204A Ceased EP0631394A1 (de) 1993-06-24 1994-06-10 Flüssigkristallanzeigevorrichtung

Country Status (3)

Country Link
EP (1) EP0631394A1 (de)
JP (1) JPH0720821A (de)
KR (1) KR950001376A (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0694900A3 (de) * 1994-07-27 1996-04-10 Sharp Kk Anzeigeeinrichtung mit aktiver Matrix und Steuerverfahren dafür
GB2307584A (en) * 1995-11-27 1997-05-28 Varintelligent A driver for a liquid crystal display

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100486228B1 (ko) * 1998-01-06 2005-06-16 삼성전자주식회사 액정표시장치구동을위한계조전압제어회로
KR100438966B1 (ko) * 2001-12-28 2004-07-03 엘지.필립스 엘시디 주식회사 다른 위상을 갖는 공통전압이 인가되는 액정표시소자 및액정표시소자의 구동방법
JP3882678B2 (ja) * 2002-05-21 2007-02-21 ソニー株式会社 表示装置
JP2006119417A (ja) * 2004-10-22 2006-05-11 Renesas Technology Corp 表示装置用駆動装置
WO2007072904A1 (ja) * 2005-12-22 2007-06-28 Citizen Holdings Co., Ltd. 液晶表示装置
JP2015031906A (ja) * 2013-08-06 2015-02-16 シナプティクス・ディスプレイ・デバイス株式会社 表示駆動装置及び表示装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0075441A2 (de) * 1981-09-18 1983-03-30 Fujitsu Limited Schaltung zur Spannungsdivision
US4742329A (en) * 1985-01-28 1988-05-03 Sanyo Electric Co., Ltd. Digital/analog converter
EP0488516A2 (de) * 1990-11-28 1992-06-03 International Business Machines Corporation Verfahren und Vorrichtung zur Anzeige von Grauwerten
JPH05100635A (ja) * 1991-10-07 1993-04-23 Nec Corp アクテイブマトリクス型液晶デイスプレイの駆動用集積回路と駆動方法

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63161495A (ja) * 1986-12-24 1988-07-05 ホシデン株式会社 液晶駆動装置
JPH0446418A (ja) * 1990-06-14 1992-02-17 Yamatake Honeywell Co Ltd ディジタル／アナログコンバータ装置
JP2610725B2 (ja) * 1991-07-18 1997-05-14 沖電気工業株式会社 自動取引装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0075441A2 (de) * 1981-09-18 1983-03-30 Fujitsu Limited Schaltung zur Spannungsdivision
US4742329A (en) * 1985-01-28 1988-05-03 Sanyo Electric Co., Ltd. Digital/analog converter
EP0488516A2 (de) * 1990-11-28 1992-06-03 International Business Machines Corporation Verfahren und Vorrichtung zur Anzeige von Grauwerten
JPH05100635A (ja) * 1991-10-07 1993-04-23 Nec Corp アクテイブマトリクス型液晶デイスプレイの駆動用集積回路と駆動方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 17, no. 451 (P - 1595) 18 August 1993 (1993-08-18) *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0694900A3 (de) * 1994-07-27 1996-04-10 Sharp Kk Anzeigeeinrichtung mit aktiver Matrix und Steuerverfahren dafür
US6151006A (en) * 1994-07-27 2000-11-21 Sharp Kabushiki Kaisha Active matrix type display device and a method for driving the same
GB2307584A (en) * 1995-11-27 1997-05-28 Varintelligent A driver for a liquid crystal display

Also Published As

Publication number Publication date
KR950001376A (ko) 1995-01-03
JPH0720821A (ja) 1995-01-24

Similar Documents

Publication Publication Date Title
KR100228248B1 (ko) 전압 출력 회로 및 화상 표시 장치
EP0303510B1 (de) Flüssigkristall-Anzeigegerät
US7268761B2 (en) Liquid crystal device, liquid crystal driving device and method of driving the same, and electronic equipment
KR100579537B1 (ko) 디지털-아날로그변환기와회로기판과전자기기및액정표시장치
KR0183487B1 (ko) 액정 표시 장치용 구동 회로
JPH05100635A (ja) アクテイブマトリクス型液晶デイスプレイの駆動用集積回路と駆動方法
JP2002014656A (ja) 多階調デジタル映像データを表示するための駆動回路及びその方法
EP0790707B1 (de) Bildsignalsteuerschaltung für Flüssigkristallanzeige mit Mehrfach-Helligkeitsabstufung mit Digital-Analog-Wandler und Steuerverfahren dafür
KR101146376B1 (ko) 액정표시장치 및 그의 구동방법
KR100205371B1 (ko) 액정의 다계화 구동회로
EP0488516A2 (de) Verfahren und Vorrichtung zur Anzeige von Grauwerten
EP0631394A1 (de) Flüssigkristallanzeigevorrichtung
KR100347065B1 (ko) 액정표시장치의 구동 시스템 및 액정 패널 구동 방법
JPH09138670A (ja) 液晶表示装置の駆動回路
KR0127102B1 (ko) 표시장치의 구동회로
US7116300B2 (en) Drive circuit and image display apparatus
KR101388350B1 (ko) 소스 드라이버 집적회로 및 이를 구비한 액정 표시 장치
JP4991127B2 (ja) 表示信号処理装置および液晶表示装置
EP0544427B1 (de) Steuerschaltung für eine Anzeigeeinheit mit digitaler Sourcesteuerung zur Erzeugung von Mehrfachpegelsteuerspannungen aus einer einzelnen externen Energiequelle
KR0150262B1 (ko) 표시장치의 구동회로
JPH05265402A (ja) 液晶表示装置の駆動方法および装置
JP3385910B2 (ja) アクティブマトリクス液晶表示装置
KR100861270B1 (ko) 액정표시장치 및 그의 구동방법
EP0804784B1 (de) Digitale ansteuerung für eine matrixanzeigesteuerungsschaltung
WO2002021499A1 (en) Circuit and method of source driving of tft lcd

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB

17P Request for examination filed

Effective date: 19950425

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

17Q First examination report despatched

Effective date: 19971208

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN REFUSED

18R Application refused

Effective date: 19980620