JPH09146072A - Liquid crystal display device - Google Patents
Liquid crystal display deviceInfo
- Publication number
- JPH09146072A JPH09146072A JP30014395A JP30014395A JPH09146072A JP H09146072 A JPH09146072 A JP H09146072A JP 30014395 A JP30014395 A JP 30014395A JP 30014395 A JP30014395 A JP 30014395A JP H09146072 A JPH09146072 A JP H09146072A
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- liquid crystal
- voltage
- detecting element
- temperature detecting
- 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.)
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Links
Landscapes
- Liquid Crystal (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、液晶表示装置の改
良に係わり、特に周囲温度が変化してもコントラストを
良好な状態に維持することができる液晶表示装置に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a liquid crystal display device, and more particularly to a liquid crystal display device capable of maintaining a good contrast even when the ambient temperature changes.
【０００２】[0002]
【従来の技術】液晶表示装置、例えばＳＴＮ方式の液晶
表示装置においては、液晶の温度依存性に起因してコン
トラストが温度に応じて変化するため、コントラスト調
整用のツマミを設け、このツマミによってコントラスト
調節用電圧ＶCONを例えば１．８Ｖを中心に上下に１Ｖ
程度の範囲で調節可能とし、この調節用電圧ＶCONによ
って液晶駆動用電圧ＶEEを例えば２０〜４０Ｖ程度の範
囲で調節してコントラストを最適な状態にすることがで
きるように構成している。2. Description of the Related Art In a liquid crystal display device, for example, an STN type liquid crystal display device, the contrast changes depending on the temperature due to the temperature dependence of the liquid crystal. Adjusting voltage V CON is, for example, 1.8V centered around 1.8V
The liquid crystal driving voltage VEE is adjusted in the range of, for example, about 20 to 40 V by the adjusting voltage V CON so that the contrast can be optimized.
【０００３】[0003]
【発明が解決しようとする課題】本発明は、周囲温度の
変化に対応して液晶駆動電圧を自動的に変更し、コント
ラストを一定の状態に維持可能な構成を提供することを
主な課題とする。それに関連して、回路素子の発熱の影
響を受けないで周囲温度の正確な検出を可能とする構成
の提供を課題の１つとする。また、電池駆動の機器に搭
載した場合のように、電源電圧が変動する場合でもその
変動に対応可能な構成の提供を課題の１つとする。ま
た、フレーム周波数等の駆動条件の違いに対応可能とす
るため、外部からのコントラスト調節用電圧ＶCON供給
による微調整が可能な構成の提供を課題の１つとする。SUMMARY OF THE INVENTION It is a principal object of the present invention to provide a structure capable of automatically changing a liquid crystal drive voltage in response to a change in ambient temperature and maintaining a constant contrast. To do. In this regard, one of the problems is to provide a configuration that enables accurate detection of the ambient temperature without being affected by the heat generation of the circuit element. Further, even when the power supply voltage fluctuates as in the case of being mounted on a battery-powered device, it is an object to provide a configuration that can cope with the fluctuation. Another object is to provide a configuration capable of fine adjustment by supplying a contrast adjustment voltage V CON from the outside in order to cope with a difference in driving conditions such as a frame frequency.
【０００４】[0004]
【課題を解決するための手段】本発明は、液晶パネル
と、液晶駆動用電圧を発生させる電源回路を有して前記
液晶パネル側方の上下方向に沿って配置される回路ユニ
ットとを備える液晶表示装置において、前記回路ユニッ
トには温度検出素子の出力によって液晶駆動用電圧を周
囲温度に応じた適正電圧に維持して出力する回路を設け
るとともに、前記温度検出素子を前記回路ユニットの発
熱量が多い回路素子よりも下方の領域に配置したことを
特徴とする。According to the present invention, there is provided a liquid crystal panel comprising a liquid crystal panel and a circuit unit having a power supply circuit for generating a liquid crystal driving voltage and arranged along the vertical direction on the side of the liquid crystal panel. In the display device, the circuit unit is provided with a circuit for maintaining and outputting the liquid crystal driving voltage at an appropriate voltage according to the ambient temperature by the output of the temperature detection element, and the temperature detection element controls the heat generation amount of the circuit unit. It is characterized in that it is arranged in a region lower than many circuit elements.
【０００５】また、本発明は、液晶パネルと、液晶駆動
用電圧を発生させる電源回路を有して前記液晶パネル側
方の上下方向に沿って配置される回路ユニットと、該回
路ユニットを覆う枠体とを備える液晶表示装置におい
て、前記回路ユニットには温度検出素子の出力によって
液晶駆動用電圧を周囲温度に応じた適正電圧に維持して
出力する回路を設けるとともに、該回路ユニットの上方
領域に発熱量が多い回路素子を配置し、下方領域に前記
温度検出素子を配置し、前記枠体には該温度検出素子に
対応した開口部を形成したことを特徴とする。Further, according to the present invention, a liquid crystal panel, a circuit unit having a power supply circuit for generating a liquid crystal driving voltage and arranged along the vertical direction on the side of the liquid crystal panel, and a frame covering the circuit unit. In the liquid crystal display device including a body, the circuit unit is provided with a circuit for maintaining and outputting the liquid crystal driving voltage at an appropriate voltage according to the ambient temperature by the output of the temperature detection element, and in the upper region of the circuit unit. A circuit element having a large amount of heat generation is arranged, the temperature detecting element is arranged in a lower region, and an opening corresponding to the temperature detecting element is formed in the frame.
【０００６】前記発熱量が多い回路素子は回路ユニット
の裏側に配置するとともに、前記温度検出素子は回路ユ
ニットの表側に配置することができる。The circuit element which generates a large amount of heat can be arranged on the back side of the circuit unit, and the temperature detecting element can be arranged on the front side of the circuit unit.
【０００７】また、前記温度検出素子と関連して回路に
接続した可変抵抗器を前記開口部から操作できるように
前記温度検出素子に近接して配置することができる。Further, a variable resistor connected to a circuit in association with the temperature detecting element can be arranged close to the temperature detecting element so that it can be operated from the opening.
【０００８】また、本発明は、供給される調節用電圧に
応じた液晶駆動用電圧を発生させる液晶駆動用電圧発生
回路に対して前記調節用電圧を供給する液晶駆動用電圧
調整回路において、供給される電源電圧をその電圧より
も低い一定の電圧に変換して上限電圧として出力する上
限電圧発生手段と、外部から供給される調節用電圧の電
圧に対応して前記上限電圧よりも低い下限電圧を発生す
る下限電圧発生手段と、第１の抵抗回路と、温度に応じ
て抵抗値が変化する第２の抵抗回路とを備え、前記第１
の抵抗回路と前記第２の抵抗回路を直列接続して前記上
限電圧と下限電圧の供給を行う端子間に接続するととも
に、前記第１の抵抗回路と前記第２の抵抗回路の接続点
の電圧を前記液晶駆動用電圧発生回路に対する調節用電
圧として供給する構成としたことを特徴とする。Further, the present invention provides a liquid crystal driving voltage adjusting circuit for supplying the adjusting voltage to a liquid crystal driving voltage generating circuit for generating a liquid crystal driving voltage according to the supplied adjusting voltage. Upper limit voltage generating means for converting the power supply voltage to a constant voltage lower than that voltage and outputting it as an upper limit voltage, and a lower limit voltage lower than the upper limit voltage corresponding to the voltage of the adjustment voltage supplied from the outside. A first resistance circuit, and a second resistance circuit whose resistance value changes according to temperature.
Of the resistance circuit and the second resistance circuit are connected in series to connect between the terminals for supplying the upper limit voltage and the lower limit voltage, and the voltage at the connection point of the first resistance circuit and the second resistance circuit. Is supplied as an adjusting voltage to the liquid crystal driving voltage generating circuit.
【０００９】[0009]
【発明の実施の形態】以下本発明の実施例を図面を参照
して説明する。図１，２において、１は液晶表示装置
（一般に液晶モジュールと称される）で、液晶パネル２
と、このパネル２の周囲部に配置した主に電源系の回路
ユニット３ａを含む複数個の回路ユニット３と、液晶パ
ネル２の周辺部及び前記回路ユニットを覆う金属製の枠
体４とを備えて構成している。液晶パネル２は、ガラス
基板の間に液晶を封入し、液晶分子を９０〜２６０度程
度ねじって保持した例えばＴＮ，ＳＴＮ方式のものを用
いることができる。電源系の回路ユニット３ａは、縦長
のプリント基板３１に後述する回路を構成する回路素子
の一部を組み込んで構成され、パネル２の側方にパネル
２の上下方向に沿って配置されている。回路ユニット３
ａの裏面には、ＤＣ−ＤＣコンバータやオペアンプ等の
ように発熱量が多い回路素子６１，６３をユニット３ａ
の上方領域に位置するように配置しているとともに、表
面には、後述する温度検出素子ＴＭや可変抵抗器ＶＲ等
の回路素子を前記発熱量の多い回路素子６１，６３の熱
影響を受けないように発熱量の多い回路素子よりも下方
位置であるユニット３ａの下方領域に配置している。
尚、液晶表示装置１は、一般にパソコンやワープロなど
の機器に組み込まれて図１の上部が上側に位置するよう
に使用される。Embodiments of the present invention will be described below with reference to the drawings. In FIGS. 1 and 2, 1 is a liquid crystal display device (generally called a liquid crystal module), which is a liquid crystal panel 2.
And a plurality of circuit units 3 mainly including a power supply circuit unit 3a arranged in the peripheral portion of the panel 2, and a metal frame 4 for covering the peripheral portion of the liquid crystal panel 2 and the circuit units. Are configured. As the liquid crystal panel 2, for example, a TN or STN type liquid crystal panel in which liquid crystal is sealed between glass substrates and liquid crystal molecules are twisted and held by about 90 to 260 degrees can be used. The circuit unit 3a of the power supply system is configured by incorporating a part of circuit elements that form a circuit described later on a vertically long printed circuit board 31, and is arranged laterally of the panel 2 along the vertical direction of the panel 2. Circuit unit 3
On the rear surface of a, circuit elements 61 and 63, such as a DC-DC converter and an operational amplifier, which generate a large amount of heat, are included in the unit 3a.
Of the circuit elements 61 and 63, which generate a large amount of heat, are provided with circuit elements such as a temperature detecting element TM and a variable resistor VR, which will be described later, on the surface thereof. As described above, it is arranged in the lower region of the unit 3a, which is a position lower than the circuit element that generates a large amount of heat.
The liquid crystal display device 1 is generally incorporated in a device such as a personal computer or a word processor and used so that the upper portion of FIG. 1 is located on the upper side.
【００１０】枠体４には、温度検出素子ＴＭが周囲温度
を検出し易くするため、並びに、温度検出素子ＴＭと近
接配置した可変抵抗器ＶＲの設定操作を容易にするた
め、この温度検出素子ＴＭと可変抵抗器ＶＲの位置と対
応して開口部４１を形成している。In order to make it easier for the temperature detecting element TM to detect the ambient temperature and to facilitate the setting operation of the variable resistor VR arranged close to the temperature detecting element TM, the temperature detecting element TM is provided on the frame body 4. The opening 41 is formed corresponding to the positions of TM and the variable resistor VR.
【００１１】次に回路構成について説明する。液晶表示
装置１は、図３に示すように、液晶パネル２と、これに
接続した走査及び信号用の駆動回路５と、この駆動回路
５にバイアス用の複数の電圧を供給する電源回路部６
と、外部から与えられる画信号や表示制御信号を受信し
て前記駆動回路５、電源回路部６に選択的に与える受信
回路７と、外部機器との接続用コネクタ８を備えてい
る。この電源回路部６の主要部、接続用コネクタ８は、
前記電源系の回路ユニット３ａに配置している。Next, the circuit configuration will be described. As shown in FIG. 3, the liquid crystal display device 1 includes a liquid crystal panel 2, a drive circuit 5 for scanning and signals connected to the liquid crystal panel 2, and a power supply circuit section 6 for supplying a plurality of bias voltages to the drive circuit 5.
And a receiving circuit 7 for receiving an image signal or a display control signal given from the outside and selectively giving it to the drive circuit 5 and the power supply circuit section 6, and a connector 8 for connecting to an external device. The main part of the power circuit section 6, the connector 8 for connection,
It is arranged in the circuit unit 3a of the power supply system.
【００１２】電源回路部６は、図３，４に示すようにコ
ネクタを介して外部機器から直流電源［ＶDD(5V)−ＧＮ
Ｄ(0V)］が与えられ、これを液晶駆動用電圧発生回路を
構成するＤＣ−ＤＣコンバータ６１に与えて出力電圧Ｖ
EEを得るように電圧変換し、これを抵抗分割回路６２に
与え、抵抗分割点から複数のバイアス用電圧を取り出
し、これらを複数のオペアンプ等によって構成したバッ
ファ回路６３を介して駆動回路５へ供給する構成として
る。ＤＣ−ＤＣコンバータ６１は、ＯＮ／ＯＦＦ端子に
受信回路７から与えられるＯＮ／ＯＦＦ信号によって動
作の開始と停止が制御されるとともに、ＶCON端子に電
圧調整回路９から与えられる電圧ＶCONに応じてその出
力電圧ＶEEを変化させることができる構成となってい
る。尚、ＤＣ−ＤＣコンバータ６１は、出力電圧ＶEEの
みならず、電圧範囲が異なる他の出力電圧を発生する構
成のものを用いることもできる。As shown in FIGS. 3 and 4, the power supply circuit section 6 is connected to a DC power supply [VDD (5V) -GN] from an external device via a connector.
D (0V)] is given to the DC-DC converter 61 which constitutes the liquid crystal driving voltage generating circuit, and the output voltage V
The voltage is converted so as to obtain EE, the voltage is applied to the resistance division circuit 62, a plurality of bias voltages are taken out from the resistance division point, and these are supplied to the drive circuit 5 via the buffer circuit 63 configured by a plurality of operational amplifiers or the like. It is configured to The DC-DC converter 61 is controlled to start and stop its operation by an ON / OFF signal given from the receiving circuit 7 to the ON / OFF terminal, and according to the voltage V CON given from the voltage adjusting circuit 9 to the V CON terminal. The output voltage VEE can be changed. Note that the DC-DC converter 61 may be configured to generate not only the output voltage VEE but also another output voltage having a different voltage range.
【００１３】電圧調整回路９は、周囲温度が変化しても
液晶パネル２のコントラストを適切な状態に維持するよ
うに、ＤＣ−ＤＣコンバータ６１に与える調節用電圧Ｖ
CONを周囲温度に応じて補正する回路構成としており、
図５に示すように、電圧ＶCO Nの変動範囲を定めるため
の上限電圧発生手段９１及び下限電圧発生手段９２と、
第１の抵抗回路９３と、温度に応じて抵抗値が変化する
第２の抵抗回路９４とを備えている。上限電圧発生手段
９１は、外部から供給される電源電圧ＶDDが、電池など
のように電圧変動が大きい電源から与えられる場合でも
対応できるように、電源電圧ＶDDが例えば３Ｖ以上の間
は一定出力電圧２．５Ｖを保証する電圧レギュレ−タ素
子によって構成している。下限電圧発生手段９２は、フ
レーム周波数等の駆動条件の違いに対応して外部からの
信号ＥｘＶCONによる微調整を受け入れ可能とするため
に、外部調節用電圧ＥｘＶCONを抵抗Ｒ１，Ｒ２によっ
て所定の比率例えば１：１に分割し、分割点の電圧を電
圧伝達素子Ａを介して出力する構成としている。この電
圧伝達素子Ａは、第１，第２抵抗回路９３，９４の温度
による抵抗値変化が抵抗Ｒ１，Ｒ２の分圧比率に影響を
与えないようにするため、ボルテ−ジフォロワ−による
オペアンプ（バッファ）等のように入力抵抗が非常に高
い素子によって構成し、下限電圧がフラ付くのを防止し
ている。外部調節用電圧ＥｘＶCONは、通常０．８Ｖ〜
２．８Ｖの間で変化するように設定されているので、抵
抗Ｒ１，Ｒ２の比率を１：１と設定すると、下限電圧発
生手段９２の出力変動範囲は、０．４Ｖ〜１．４Ｖとな
る。The voltage adjusting circuit 9 adjusts the voltage V applied to the DC-DC converter 61 so as to maintain the contrast of the liquid crystal panel 2 in an appropriate state even if the ambient temperature changes.
It has a circuit configuration that corrects CON according to the ambient temperature,
As shown in FIG. 5, the upper limit voltage generating means 91 and the lower limit voltage generating means 92 for determining the fluctuation range of the voltage V CO N,
It is provided with a first resistance circuit 93 and a second resistance circuit 94 whose resistance value changes according to temperature. The upper limit voltage generating means 91 is capable of coping with the case where the power supply voltage VDD supplied from the outside is supplied from a power supply whose voltage fluctuation is large such as a battery, so that the constant output voltage is maintained while the power supply voltage VDD is, for example, 3V or more. It is composed of a voltage regulator element that guarantees 2.5V. The lower limit voltage generation unit 92 sets the external adjustment voltage ExV CON to a predetermined value by resistors R1 and R2 in order to accept fine adjustment by an external signal ExV CON in response to a difference in driving conditions such as a frame frequency. The ratio is divided into, for example, 1: 1 and the voltage at the dividing point is output via the voltage transfer element A. This voltage transfer element A is an operational amplifier (buffer) using a voltage follower so that the resistance change due to the temperature of the first and second resistance circuits 93 and 94 does not affect the voltage division ratio of the resistors R1 and R2. ), Etc., has a very high input resistance to prevent the lower limit voltage from fluctuating. The external adjustment voltage ExV CON is usually 0.8V ~
Since it is set to change between 2.8V, if the ratio of the resistors R1 and R2 is set to 1: 1, the output fluctuation range of the lower limit voltage generation means 92 becomes 0.4V to 1.4V. .
【００１４】第１抵抗回路９３は、抵抗Ｒ４と可変抵抗
器ＶＲを直列接続して構成し、第２抵抗回路９４は、温
度によって抵抗値が変化する例えばサーミスタ等の温度
検出素子ＴＭと抵抗Ｒ３を並列接続して構成している。
この第１の抵抗回路９３と第２の抵抗回路９４の直列回
路を上限電圧発生手段９１と下限電圧発生手段９２の出
力端子間に接続している。そして、第１の抵抗回路９３
と第２の抵抗回路９４の接続点の電圧が調節用電圧Ｖ
CONとしてＤＣ−ＤＣコンバータ６１のＶCON端子に供給
される。この調節用電圧ＶCONは、周囲温度の変化に伴
って温度検出素子ＴＭの抵抗値が変化するので、周囲温
度に応じて電圧値が変化する。また、調節用電圧ＶCON
は、可変抵抗器ＶＲの抵抗値を変化させることよって上
下に微調整することができるし、外部から供給する外部
調節用電圧ＥｘＶCONを変化させることによっても微調
整することもできる。The first resistance circuit 93 comprises a resistor R4 and a variable resistor VR connected in series, and the second resistance circuit 94 comprises a temperature detection element TM such as a thermistor whose resistance value changes with temperature and a resistance R3. Are connected in parallel.
The series circuit of the first resistance circuit 93 and the second resistance circuit 94 is connected between the output terminals of the upper limit voltage generating means 91 and the lower limit voltage generating means 92. Then, the first resistance circuit 93
And the voltage at the connection point of the second resistance circuit 94 is the adjustment voltage V
It is supplied to the V CON terminal of the DC-DC converter 61 as CON. Since the resistance value of the temperature detection element TM changes with the change of the ambient temperature, the voltage value of the adjustment voltage V CON changes according to the ambient temperature. Also, the adjustment voltage V CON
Can be finely adjusted up and down by changing the resistance value of the variable resistor VR, and can also be finely adjusted by changing the external adjustment voltage ExV CON supplied from the outside.
【００１５】液晶パネル２は温度によってコントラスト
が変化するが、コントラストを一定に保つための温度と
液晶駆動用電圧ＶEEの関係は例えば図６に（ａ）として
示すように実験的に求めることができる。そして、この
液晶駆動用電圧ＶEEを発生させるための周囲温度に応じ
た調節用電圧ＶCONも同図に（ｂ）として示すように実
験的に求めることができる。したがって、電圧調整回路
９から出力される調節用電圧ＶCONが、温度に応じて同
図の（ｂ）に示されるような特性を描くように、第１抵
抗回路９３及び第２抵抗回路９４を構成する抵抗の種類
や抵抗値を実験的に求めて設定することにより、温度変
化に係わらず液晶パネル２のコントラストを良好なほぼ
一定の状態に保つことができる液晶表示装置１を提供す
ることができる。Although the contrast of the liquid crystal panel 2 changes depending on the temperature, the relationship between the temperature for keeping the contrast constant and the liquid crystal drive voltage VEE can be experimentally obtained as shown in (a) of FIG. 6, for example. . Then, the adjusting voltage V CON corresponding to the ambient temperature for generating the liquid crystal driving voltage VEE can be experimentally obtained as shown in FIG. Therefore, the first resistance circuit 93 and the second resistance circuit 94 are controlled so that the adjusting voltage V CON output from the voltage adjusting circuit 9 draws the characteristic as shown in FIG. It is possible to provide the liquid crystal display device 1 that can maintain the contrast of the liquid crystal panel 2 in a good and substantially constant state regardless of the temperature change by experimentally obtaining and setting the types and resistance values of the resistors to be configured. it can.
【００１６】このようにすることにより、液晶駆動用電
圧ＶEEは、周囲温度が低温の場合は高い電圧となるが、
周囲温度が高くなると自動的に低い電圧に変更されるの
で、回路素子の高温時における許容損失を小さく設定す
ることができる。したがって、電源回路部６や駆動回路
５等を構成する回路素子を許容損失の小さい、小型、薄
型化に適した部品によって構成でき、装置全体を小型、
薄型、軽量化することができる。By doing so, the liquid crystal driving voltage VEE becomes high when the ambient temperature is low,
Since the voltage is automatically changed to a low voltage when the ambient temperature rises, it is possible to set the allowable loss at a high temperature of the circuit element to be small. Therefore, the circuit elements constituting the power supply circuit section 6, the drive circuit 5 and the like can be constituted by parts having small allowable loss and suitable for miniaturization and thinning.
It can be thin and lightweight.
【００１７】ところで、温度検出素子ＴＭが回路ユニッ
ト３ａの発熱部品の熱によって加熱されると、周囲温度
の正確な検出ができなくなる恐れがあるが、ず１，２の
ように温度検出素子ＴＭを回路ユニット３ａの発熱量が
上位にランクされる回路素子（ＤＣ−ＤＣコンバータ６
１やバッファ回路６３を構成するオペアンプ等）よりも
下方の領域に配置したので、発熱回路素子による不要加
熱を防ぎ、正確な温度検出を行うことができる。また、
発熱量が多い前記回路素子は回路ユニット３ａの裏側に
配置するとともに、温度検出素子ＴＭは回路ユニット３
ａの表側に配置したので、発熱回路素子による不要加熱
をより一層防ぐことができる。また、枠体４には温度検
出素子ＴＭに対応した開口部４１を形成したので、開口
部４１によって、温度検出素子ＴＭ周囲の空気の出入り
を促進し、周囲温度の正確な検出を可能とすることがで
きる。また、開口部４１に望むように温度検出素子ＴＭ
に隣接して可変抵抗器ＶＲを配置したので、放熱用の開
口部４１を共通に利用して可変抵抗器ＶＲの調節を行う
ことができる。尚、この開口部４１は、液晶表示装置１
を他の機器に組み込むことによって、通常、他の機器の
ケースによって隠される位置に設けているので、他の機
器の外観を損なうことがないように配慮している。If the temperature detecting element TM is heated by the heat of the heat-generating components of the circuit unit 3a, it may not be possible to accurately detect the ambient temperature. The circuit element (DC-DC converter 6) in which the heat generation amount of the circuit unit 3a is ranked higher.
1 and the operational amplifier forming the buffer circuit 63) are arranged in a lower region, so that unnecessary heating by the heating circuit element can be prevented and accurate temperature detection can be performed. Also,
The circuit element which generates a large amount of heat is arranged on the back side of the circuit unit 3a, and the temperature detecting element TM is arranged in the circuit unit 3a.
Since it is arranged on the front side of a, it is possible to further prevent unnecessary heating by the heating circuit element. Further, since the opening 41 corresponding to the temperature detecting element TM is formed in the frame body 4, the opening 41 promotes the inflow and outflow of the air around the temperature detecting element TM, thereby enabling the accurate detection of the ambient temperature. be able to. Further, the temperature detecting element TM can be formed in the opening 41 as desired.
Since the variable resistor VR is disposed adjacent to the variable resistor VR, the variable resistor VR can be adjusted by commonly using the heat dissipation opening 41. It should be noted that this opening 41 is provided in the liquid crystal display device 1.
Since it is provided in a position hidden by the case of another device by incorporating it into another device, consideration is given not to spoil the appearance of the other device.
【００１８】[0018]
【発明の効果】以上のように、本発明によれば、周囲温
度の変化に対応して液晶駆動電圧を自動的に変更し、コ
ントラストを一定の状態に維持可能な構成を提供するこ
とができる。また、周囲温度の検出を、回路素子の発熱
の影響をほとんど受けないで正確に行うことができる。
また、電池駆動の機器に搭載した場合のように、電源電
圧が変動する場合でも、その変動に影響を受けにくい構
成とすることができる。また、外部からのコントラスト
調節用電圧供給による微調整が可能な構成とし、フレー
ム周波数等の駆動条件の違いに対応可能とすることがで
る。また、電源回路部や駆動回路等を構成する回路素子
を許容損失の小さい、小型、薄型化に適した部品によっ
て構成でき、装置全体を小型、薄型、軽量化することが
できる。As described above, according to the present invention, it is possible to provide a configuration in which the liquid crystal drive voltage is automatically changed in response to the change in ambient temperature and the contrast can be maintained in a constant state. . Further, the ambient temperature can be accurately detected with almost no influence of heat generation of the circuit element.
Further, even when the power supply voltage fluctuates as in the case of being mounted on a battery-powered device, it is possible to make the structure less susceptible to the fluctuation. Further, it is possible to make a fine adjustment by supplying a voltage for contrast adjustment from the outside so that it is possible to cope with a difference in driving conditions such as a frame frequency. Further, the circuit elements constituting the power supply circuit section, the drive circuit, etc. can be constituted by parts having small allowable loss and suitable for miniaturization and thinning, and the entire device can be miniaturized, thinned, and lightened.
【図１】本発明実施例に係る液晶表示装置の平面図であ
る。FIG. 1 is a plan view of a liquid crystal display device according to an embodiment of the present invention.
【図２】図１のＩ−Ｉ断面図である。FIG. 2 is a sectional view taken along line II of FIG.
【図３】本発明実施例に係る液晶表示装置の概略回路を
示すブロック図である。FIG. 3 is a block diagram showing a schematic circuit of a liquid crystal display device according to an embodiment of the present invention.
【図４】同実施例の電源回路部の回路ブロック図であ
る。FIG. 4 is a circuit block diagram of a power supply circuit unit of the embodiment.
【図５】同実施例の電圧調整回路の回路図である。FIG. 5 is a circuit diagram of a voltage adjusting circuit according to the same embodiment.
【図６】温度と液晶駆動用電圧ＶEE、温度と調節用電圧
ＶCONの関係を示す特性図である。FIG. 6 is a characteristic diagram showing a relationship between temperature and liquid crystal driving voltage VEE, and temperature and adjustment voltage V CON .
１ 液晶表示装置 ２ 液晶パネル ３ａ 回路ユニット ４ 枠体 ５ 駆動回路 ６ 電源回路部 ６１ ＤＣ−ＤＣコンバータ ９ 電圧調整回路 ９１ 下限電圧発生手段 ９２ 上限電圧発生手段 ９３ 第１抵抗回路 ９４ 第２抵抗回路 ＴＭ 温度検出素子 ＶＲ 可変抵抗器 DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 2 Liquid crystal panel 3a Circuit unit 4 Frame 5 Drive circuit 6 Power supply circuit part 61 DC-DC converter 9 Voltage adjustment circuit 91 Lower limit voltage generation means 92 Upper limit voltage generation means 93 1st resistance circuit 94 2nd resistance circuit TM Temperature sensing element VR Variable resistor
Claims (5)
せる電源回路を有して前記液晶パネル側方の上下方向に
沿って配置される回路ユニットとを備える液晶表示装置
において、前記回路ユニットには温度検出素子の出力に
よって液晶駆動用電圧を周囲温度に応じた適正電圧に維
持して出力する回路を設けるとともに、前記温度検出素
子を前記回路ユニットの発熱量が多い回路素子よりも下
方の領域に配置したことを特徴とする液晶表示装置。1. A liquid crystal display device comprising: a liquid crystal panel; and a circuit unit having a power supply circuit for generating a liquid crystal driving voltage and arranged along a vertical direction on a side of the liquid crystal panel. Is provided with a circuit for maintaining and outputting the liquid crystal driving voltage at an appropriate voltage according to the ambient temperature by the output of the temperature detecting element, and the temperature detecting element is located in a region below the circuit element where the heat generation amount of the circuit unit is large. A liquid crystal display device characterized by being arranged in.
せる電源回路を有して前記液晶パネル側方の上下方向に
沿って配置される回路ユニットと、該回路ユニットを覆
う枠体とを備える液晶表示装置において、前記回路ユニ
ットには温度検出素子の出力によって液晶駆動用電圧を
周囲温度に応じた適正電圧に維持して出力する回路を設
けるとともに、該回路ユニットの上方領域に発熱量が多
い回路素子を配置し、下方領域に前記温度検出素子を配
置し、前記枠体には該温度検出素子に対応した開口部を
形成したことを特徴とする液晶表示装置。2. A liquid crystal panel, a circuit unit having a power supply circuit for generating a liquid crystal driving voltage and arranged along the vertical direction on the side of the liquid crystal panel, and a frame body covering the circuit unit. In the liquid crystal display device, the circuit unit is provided with a circuit for maintaining and outputting the liquid crystal driving voltage at an appropriate voltage according to the ambient temperature by the output of the temperature detecting element, and a large amount of heat is generated in the upper region of the circuit unit. A liquid crystal display device characterized in that a circuit element is arranged, the temperature detecting element is arranged in a lower region, and an opening corresponding to the temperature detecting element is formed in the frame.
トの裏側に配置するとともに、前記温度検出素子は回路
ユニットの表側に配置したことを特徴とする請求項１も
しくは請求項２に記載の液晶表示装置。3. The liquid crystal according to claim 1, wherein the circuit element generating a large amount of heat is arranged on the back side of the circuit unit, and the temperature detecting element is arranged on the front side of the circuit unit. Display device.
した可変抵抗器を前記開口部から操作できるように前記
温度検出素子に近接して配置したことを特徴とする請求
項２に記載の液晶表示装置。4. The variable resistor connected to a circuit in association with the temperature detecting element is arranged close to the temperature detecting element so as to be operable from the opening. Liquid crystal display device.
用電圧を発生させる液晶駆動用電圧発生回路に対して前
記調節用電圧を供給する液晶駆動用電圧調整回路におい
て、供給される電源電圧をその電圧よりも低い一定の電
圧に変換して上限電圧として出力する上限電圧発生手段
と、外部から供給される調節用電圧の電圧に対応して前
記上限電圧よりも低い下限電圧を発生する下限電圧発生
手段と、第１の抵抗回路と、温度に応じて抵抗値が変化
する第２の抵抗回路とを備え、前記第１の抵抗回路と前
記第２の抵抗回路を直列接続して前記上限電圧と下限電
圧の供給を行う端子間に接続するとともに、前記第１の
抵抗回路と前記第２の抵抗回路の接続点の電圧を前記液
晶駆動用電圧発生回路に対する調節用電圧として供給す
る構成としたことを特徴とする液晶駆動用電圧調整回
路。5. A liquid crystal driving voltage adjusting circuit for supplying the adjusting voltage to a liquid crystal driving voltage generating circuit for generating a liquid crystal driving voltage according to the supplied adjusting voltage. To a constant voltage lower than the voltage and output it as an upper limit voltage, and a lower limit that generates a lower limit voltage lower than the upper limit voltage corresponding to the voltage of the adjustment voltage supplied from the outside. A voltage generating means, a first resistance circuit, and a second resistance circuit whose resistance value changes according to temperature are provided, and the first resistance circuit and the second resistance circuit are connected in series to form the upper limit. And a voltage at a connection point of the first resistance circuit and the second resistance circuit is supplied as an adjustment voltage to the liquid crystal driving voltage generation circuit, while being connected between terminals for supplying a voltage and a lower limit voltage. What you did Characteristic liquid crystal drive voltage adjustment circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30014395A JP3229792B2 (en) | 1995-11-17 | 1995-11-17 | Liquid crystal display |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30014395A JP3229792B2 (en) | 1995-11-17 | 1995-11-17 | Liquid crystal display |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001182063A Division JP3588340B2 (en) | 2001-06-15 | 2001-06-15 | Liquid crystal display device and its driving voltage adjusting circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH09146072A true JPH09146072A (en) | 1997-06-06 |
| JP3229792B2 JP3229792B2 (en) | 2001-11-19 |
Family
ID=17881266
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30014395A Expired - Fee Related JP3229792B2 (en) | 1995-11-17 | 1995-11-17 | Liquid crystal display |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3229792B2 (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999027415A1 (en) * | 1997-11-25 | 1999-06-03 | Hitachi, Ltd. | Power source circuit having temperature compensating function and liquid crystal display device incorporating the same |
| US6414740B1 (en) | 1999-06-01 | 2002-07-02 | Nec Corporation | LCD having temperature detection elements provided on an active-substrate |
| JP2004317905A (en) * | 2003-04-18 | 2004-11-11 | Nec Access Technica Ltd | Liquid crystal monitor unit |
| US6853409B2 (en) | 1999-12-22 | 2005-02-08 | Yutaka Takeishi | Signal processing circuit board and liquid crystal display apparatus with variable resistor which are hardly declined in the mechanical strength while its variable resistor is not limited to one particular location for the installation |
| JP2005173236A (en) * | 2003-12-11 | 2005-06-30 | Seiko Epson Corp | Electrooptical device and method for manufacturing the same, and electronic equipment |
| US7518669B2 (en) | 2001-06-01 | 2009-04-14 | Lg Display Co., Ltd. | LCD and a shield cover for the LCD |
| JP2011065165A (en) * | 2010-10-04 | 2011-03-31 | Hitachi Displays Ltd | Liquid crystal display |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7404690B2 (en) | 2019-07-23 | 2023-12-26 | セイコーエプソン株式会社 | Electro-optical panels, electro-optical devices and electronic equipment |
-
1995
- 1995-11-17 JP JP30014395A patent/JP3229792B2/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1999027415A1 (en) * | 1997-11-25 | 1999-06-03 | Hitachi, Ltd. | Power source circuit having temperature compensating function and liquid crystal display device incorporating the same |
| US6414740B1 (en) | 1999-06-01 | 2002-07-02 | Nec Corporation | LCD having temperature detection elements provided on an active-substrate |
| US6853409B2 (en) | 1999-12-22 | 2005-02-08 | Yutaka Takeishi | Signal processing circuit board and liquid crystal display apparatus with variable resistor which are hardly declined in the mechanical strength while its variable resistor is not limited to one particular location for the installation |
| US7046118B2 (en) | 1999-12-22 | 2006-05-16 | Nec Lcd Technologies, Ltd. | Signal processing circuit board with variable resistor which is hardly declined in the mechanical strength while its variable resistor is not limited to one particular location for the installation |
| US7518669B2 (en) | 2001-06-01 | 2009-04-14 | Lg Display Co., Ltd. | LCD and a shield cover for the LCD |
| JP2004317905A (en) * | 2003-04-18 | 2004-11-11 | Nec Access Technica Ltd | Liquid crystal monitor unit |
| JP2005173236A (en) * | 2003-12-11 | 2005-06-30 | Seiko Epson Corp | Electrooptical device and method for manufacturing the same, and electronic equipment |
| JP4525065B2 (en) * | 2003-12-11 | 2010-08-18 | セイコーエプソン株式会社 | Electro-optical device, manufacturing method thereof, and electronic apparatus |
| JP2011065165A (en) * | 2010-10-04 | 2011-03-31 | Hitachi Displays Ltd | Liquid crystal display |
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| Publication number | Publication date |
|---|---|
| JP3229792B2 (en) | 2001-11-19 |
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