WO1999027415A1 - Circuit d'alimentation en energie dote d'une fonction de compensation de la temperature et dispositif d'affichage a cristaux liquides comportant un tel circuit - Google Patents

Circuit d'alimentation en energie dote d'une fonction de compensation de la temperature et dispositif d'affichage a cristaux liquides comportant un tel circuit Download PDF

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Publication number
WO1999027415A1
WO1999027415A1 PCT/JP1997/004286 JP9704286W WO9927415A1 WO 1999027415 A1 WO1999027415 A1 WO 1999027415A1 JP 9704286 W JP9704286 W JP 9704286W WO 9927415 A1 WO9927415 A1 WO 9927415A1
Authority
WO
WIPO (PCT)
Prior art keywords
circuit
voltage
liquid crystal
power supply
supply circuit
Prior art date
Application number
PCT/JP1997/004286
Other languages
English (en)
Japanese (ja)
Inventor
Shinsaku Chiba
Yasuaki Kondo
Original Assignee
Hitachi, Ltd.
Hitachi Device Engineering Co., Ltd.
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 Hitachi, Ltd., Hitachi Device Engineering Co., Ltd. filed Critical Hitachi, Ltd.
Priority to PCT/JP1997/004286 priority Critical patent/WO1999027415A1/fr
Publication of WO1999027415A1 publication Critical patent/WO1999027415A1/fr

Links

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
    • 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
    • G09G2320/04—Maintaining the quality of display appearance
    • G09G2320/041—Temperature compensation
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/02—Details of power systems and of start or stop of display operation
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/06—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using resistors or capacitors, e.g. potential divider
    • H02M3/07—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using resistors or capacitors, e.g. potential divider using capacitors charged and discharged alternately by semiconductor devices with control electrode, e.g. charge pumps

Definitions

  • the present invention relates to a power supply circuit (DC-DC converter) having a temperature compensation function and a liquid product display device incorporating the same, and in particular, to high-speed driving by a multi-line selection method (Multi-Line Selection).
  • the present invention relates to a power supply circuit for performing the above and a liquid product display device incorporating the same.
  • a main use of a liquid crystal display device is a notebook personal computer, and improvement of a response speed and improvement of image quality are demanded by users.
  • single-part nematic liquid crystal display (STN) liquid crystal display devices are required to have an advantage in terms of production cost and image quality that is thinner than active liquid crystal display devices such as TFT liquid crystals in terms of image quality. Therefore, an enhanced 'high addressing drive system' has been proposed which combines a drive for simultaneously selecting two or more scan lines with a shadowing correction circuit.
  • STN single-part nematic liquid crystal display
  • Japanese Patent Application Laid-Open No. 9-230306 discloses a device for compensating the voltage of a data drive circuit with a temperature.However, only the data drive voltage is subject to temperature compensation, and the bias ratio changes during temperature compensation. Was controlled.
  • a typical configuration of a power supply circuit (DC-DC converter) with a built-in temperature compensation circuit is as shown in Fig. 11.
  • a predetermined control voltage (Vpc) from the personal computer is applied to the voltage using an operational amplifier (0P2).
  • the output is received by the lower circuit, and the output is adjusted to an appropriate voltage at an arbitrary temperature by using a split resistor (R10, R11) and a thermistor (TH).
  • This circuit consists of an operational amplifier (0P2), a thermistor (TH), a resistor (R10, R1 U R12), and a capacitor (C6) as components for the temperature compensation circuit.
  • the problem is that the area occupied on the printed circuit board increases. It is also desirable that the configuration be such that the temperature compensation function can be easily adjusted so that the optimum driving voltage is obtained even when the liquid crystal material is changed.
  • a first object of the present invention is to provide a power supply circuit having a stable temperature compensation function and a small circuit scale, and a liquid crystal display device incorporating the same.
  • a second object of the present invention is to provide a power supply circuit which facilitates adjustment of a temperature compensation function due to a change in liquid crystal material or a reference voltage of a personal computer which differs depending on a model, and a liquid crystal display incorporating the same. It is to provide a device.
  • a power supply circuit having a temperature compensation function includes a first booster circuit (L2) for generating a positive scan drive voltage VH by boosting a predetermined input voltage Vdd. -l ⁇ 2-3, TR2, TR3, CI ⁇ C2, Dl, D2) and a second booster circuit (L2-l) for generating a negative scanning drive voltage VL around a predetermined control voltage Vpc.
  • a DC-DC converter circuit comprising a plurality of resistors (R1 to R5) for dividing the voltage between the positive scanning drive voltage and a predetermined reference voltage GND, and an operational amplifier 0P1 for supplying the control voltage; And a thermistor element TH provided in parallel with the two first resistors R1.
  • the power supply circuit includes a variable resistor having one end connected to the reference voltage, and a variable resistor Rex connected in parallel to at least one second resistor R4 of the resistor. Fine adjustments can be made flexibly even when the liquid crystal material is changed.
  • the thermistor element TH is equipped with a drive circuit for connecting the liquid crystal display element and the print substrate at an intermediate point between the center and the end of the liquid crystal display element in the direction in which the printed circuit board extends. Between multiple tape carrier packages It is desirable to be arranged in the area.
  • FIG. 1 is a diagram showing a schematic configuration of a power supply circuit (DC DC converter) having a temperature compensation function according to the present invention.
  • FIG. 2 is a diagram schematically showing a full rest configuration of the power supply circuit according to the present invention.
  • FIG. 3 is an exploded perspective view of the liquid product display device according to the present invention.
  • FIG. 4 is a diagram for explaining the location of a misalignment ( ⁇ ) on the print substrate on the scanning line drive circuit side of the liquid crystal display device according to the present invention.
  • FIG. 5 is an image layout diagram of an arrangement of a temperature compensation circuit in a conventional power supply circuit.
  • FIG. 6 is a diagram showing the temperature dependence of the liquid crystal, which is a correlation between the ambient temperature and the optimal driving voltage.
  • FIG. 7 is a diagram showing a correlation between an optimum drive voltage and a predetermined voltage (Vpc) at each temperature compensated by a power supply circuit having a temperature compensation function according to the present invention.
  • FIG. 8 is a schematic diagram showing an overall configuration of a power supply circuit according to the present invention.
  • FIG. 9 is a diagram showing a correlation between driving voltages from a power supply circuit.
  • FIG. 10 is a diagram showing a connection relationship between a power supply circuit and a drive circuit.
  • FIG. 11 is a diagram showing a schematic configuration of a power supply circuit having a conventional temperature compensation function. [Best mode for carrying out the invention]
  • a predetermined control voltage (Vpc) from a device incorporating a liquid crystal display device such as a personal computer (PC) is controlled by a temperature.
  • Vpc a predetermined control voltage
  • PC personal computer
  • the operation principle of the power supply circuit according to the present invention is to perform feedback so as to change the maximum drive voltage (VH) in order to keep the reference voltage (Vref) constant.
  • FIG. 2 is a diagram schematically showing an overall configuration of a power supply circuit according to the present invention.
  • a logic power supply voltage Vop supplied to a data drive circuit a coil Ll, a transistor TR1, a diode D5, a capacitor C5, a resistor It consists of a non-insulated step-up chopper power supply circuit composed of R6.
  • the basic operation of this power supply circuit is that when the switching transistor TR1 is turned on by the switch control circuit, energy is stored in the inductor coil L1 and added to the input voltage through the diode D5 when the switching transistor TR1 is turned off.
  • a voltage Vop is generated across load resistor R6.
  • the drive voltages VH and VL supplied as the selection voltage of the scan drive circuit are composed of a C-cut winding boosting power supply circuit that is effective when generating a high voltage and a small current. Specifically, transformers (L2_l, L2-2, L2-3), transistors (TR2, TR3), diodes (Dl, D2, D3, D4), capacitors (Cl, C2, C3, C4) And load resistance (R1 to R4, RR).
  • a voltage VH is generated by multiplying the collector voltage by the number of turns with a predetermined voltage Vdd as a middle point.
  • a rectifier circuit that combines a capacitor and a diode is used to use the generated voltage VL on the negative side.
  • the drive voltage VH is feedback-controlled to maintain a constant value corresponding to the input of the predetermined voltage Vpc. Also, in order to ensure the symmetry of the drive voltages VH and VL, the VH-VL I ij voltage is divided, compared with the internal reference voltage (Vop), and the series regulator (SR) mounted on the VL line is It operates and controls the VL line so that the center potential between VH and VL is constant.
  • the control circuit (power supply circuit) of these DC-DC converters is a so-called pulse width modulation (PWM) method, and the influence of noise on other circuits such as the same-printed circuit board and the drive circuit is reduced. A little ,.
  • PWM pulse width modulation
  • the current I I flowing between VH and Vref can be expressed as follows, assuming that the current flowing between Vpc and Vref is 12 and the current flowing between Vref and GND is 13.
  • Vpc about 0.8V
  • VH can be experimentally set to about 18.82V near the black screen, so if you calculate in the same way as the deformation of Vpc in equation (3) at about 1.8V,
  • R3, R4, and R5 are the above values regardless of the temperature.
  • the resistance value of only Z changes with temperature, and the resistance R TH of the thermistor TH at an arbitrary temperature T (absolute temperature) is the reference temperature (25 ° If the resistance value at the absolute temperature T Q ) is R réelle,
  • R 1 + R TH It is represented by R 1 + R TH.
  • R2 is set to about 360 ⁇ in consideration of the number of resistance steps, and the resistance of R1 is approximated by 75 ⁇ ⁇ in consideration of changes at each temperature.
  • variable resistor Rex also functions as absent.
  • the predetermined voltage Vpc By changing the predetermined voltage Vpc by changing the liquid material, etc., ⁇ Fine adjustment of the appropriate driving voltage
  • the predetermined control voltage Vpc of the center value can be easily adjusted while making the temperature compensation characteristics of the optimum driving voltage of the liquid crystal the same.
  • the power supply circuit according to the present invention has an additional effect of reducing the circuit size as compared with the typical prior art.
  • the power supply circuit described above is mounted on the print wiring board 15 on the scanning drive circuit side in the liquid crystal display device 1 shown in FIG.
  • the liquid crystal display element 18 has an upper frame 10 having a liquid crystal display window 3, a silicon spacer 13, a frame spacer 19, a light guide plate 24, and rubber bushes 21 disposed at both ends. It is composed of a combination of an intermediate mold 16, in which a light tube housing part with a tube 20 is mounted, and a lower frame 11.
  • the frame area of the liquid crystal display device that is, the area around the liquid crystal display window 3 of the upper frame 10 as small as possible.
  • a print substrate 14 with a data drive circuit and a scan drive circuit are mounted.
  • Printed circuit boards 15 must be as small as possible.
  • the printed circuit board 14 is a tape carrier package on which a scanning drive circuit is mounted on a printed circuit board connected by a joiner 12 for supplying a power supply voltage and a data signal supplied from the printed circuit board 15.
  • a joiner 12 for supplying a power supply voltage and a data signal supplied from the printed circuit board 15.
  • the area for connecting and arranging 17 there is also an area for mounting the above-mentioned power supply circuit, etc.How to reduce the size of this printed circuit board 15 area is key to reducing the frame area .
  • the temperature compensation circuit is shared by the DC / DC converter circuit, a mounting capacitor for the thermistor TH is added as an external component. Only with this method, warm-up becomes possible.
  • the thermistor TH is disposed on the printed circuit board at a position close to the liquid crystal display element 18 so that the average temperature of the liquid display element is reflected as much as possible.
  • an area between the tape carrier package 17 on which a plurality of scanning drive circuits are mounted is defined. desirable.
  • the DC-DC converter power supply circuit shown in FIG. 2 is further provided with a voltage dividing circuit shown in FIG. 8, thereby generating power supply to be supplied to the scan drive circuit and the data drive circuit.
  • a voltage dividing circuit shown in FIG. 8 By dividing the drive voltage (VH, VL), the center voltage VI and the voltage (V0, V2) supplied to the data drive circuit are generated, and as shown in Fig. 9, the scan drive voltage selection voltage Vscan In this case, the drive voltage (VH, VL) is used as it is, and the drive voltage VI is used as a non-selective voltage.
  • these drive voltages (V0, VI, V2) are selectively supplied for each column according to the display data signal.
  • FIG. 10 shows the schematic configuration of the connection between the power supply circuit and the drive circuit of the entire liquid crystal display device, and the voltage generated by the power supply circuit is supplied as described above.
  • the circuit shown in Fig. 8 can be defined as a power circuit, but in the above description and in a narrow sense, the circuit shown in Fig. 2 and the circuit shown in Fig. 1 are suitable.
  • a DC-DC converter can also be defined as a power supply circuit.

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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)

Abstract

L'invention se rapporte à un circuit d'alimentation en énergie doté d'une fonction de compensation de la température et d'une structure de petit circuit. Ce circuit d'alimentation en énergie doté d'une fonction de compensation de la température est constitué d'un premier circuit de survoltage (L2-1 à 2-3. TR2, TR3, C1, C2, D1 et D2) conçu pour générer une tension positive de commande du balayage VH par amplification d'une tension d'entrée préétablie Vdd, d'un second circuit de survoltage (L2-1 à 2-3, TR2, TR3, C3, C4, D3 et D4) ) conçu pour générer une tension négative de commande du balayage VL proche de la valeur d'une tension de commande préétablie Vpc, et d'un convertisseur C.C.-C.C. qui ajuste les tensions positive et négative de commande du balayage en accord avec la tension de commande Vpc en provenance de l'extérieur. Ce circuit est composé d'une pluralité de résistances (R1-R5) qui divisent la différence de tension entre la tension positive de commande du balayage et une tension de référence préétablie GND, d'un amplificateur opérationnel OP1 qui délivre la tension de commande Vpc, et d'une thermistance TH qui est montée en parallèle avec au moins une des résistances (R1-R5), et notamment la première résistance.
PCT/JP1997/004286 1997-11-25 1997-11-25 Circuit d'alimentation en energie dote d'une fonction de compensation de la temperature et dispositif d'affichage a cristaux liquides comportant un tel circuit WO1999027415A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/JP1997/004286 WO1999027415A1 (fr) 1997-11-25 1997-11-25 Circuit d'alimentation en energie dote d'une fonction de compensation de la temperature et dispositif d'affichage a cristaux liquides comportant un tel circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP1997/004286 WO1999027415A1 (fr) 1997-11-25 1997-11-25 Circuit d'alimentation en energie dote d'une fonction de compensation de la temperature et dispositif d'affichage a cristaux liquides comportant un tel circuit

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WO1999027415A1 true WO1999027415A1 (fr) 1999-06-03

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20100017041A (ko) * 2008-08-05 2010-02-16 엘지디스플레이 주식회사 온도 특성 보상을 위한 구동전압 생성회로 및 이를 구비한 액정표시장치
KR101033124B1 (ko) * 2004-12-28 2011-05-11 엘지디스플레이 주식회사 액정표시장치 및 그 구동방법
US8029187B2 (en) * 2007-02-21 2011-10-04 Kyocera Corporation Apparatus, system and method for high resolution identification with temperature dependent resistive device

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0239023A (ja) * 1988-07-28 1990-02-08 Sharp Corp 液晶駆動温度補償回路
JPH0876096A (ja) * 1994-09-06 1996-03-22 Casio Comput Co Ltd 液晶表示装置の温度補償方法
JPH09146072A (ja) * 1995-11-17 1997-06-06 Sanyo Electric Co Ltd 液晶表示装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0239023A (ja) * 1988-07-28 1990-02-08 Sharp Corp 液晶駆動温度補償回路
JPH0876096A (ja) * 1994-09-06 1996-03-22 Casio Comput Co Ltd 液晶表示装置の温度補償方法
JPH09146072A (ja) * 1995-11-17 1997-06-06 Sanyo Electric Co Ltd 液晶表示装置

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101033124B1 (ko) * 2004-12-28 2011-05-11 엘지디스플레이 주식회사 액정표시장치 및 그 구동방법
US8029187B2 (en) * 2007-02-21 2011-10-04 Kyocera Corporation Apparatus, system and method for high resolution identification with temperature dependent resistive device
KR20100017041A (ko) * 2008-08-05 2010-02-16 엘지디스플레이 주식회사 온도 특성 보상을 위한 구동전압 생성회로 및 이를 구비한 액정표시장치
KR101594061B1 (ko) * 2008-08-05 2016-02-16 엘지디스플레이 주식회사 온도 특성 보상을 위한 구동전압 생성회로 및 이를 구비한 액정표시장치

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