JPS5913220A - Liquid crystal display device and driving method thereof - Google Patents

Abstract

PURPOSE:To obtain a thermal writing type LCD having a high writing speed and small power consumption, by providing heater electrodes to be used exclusively for respective liquid crystal layers on both sides of a thin resin sheet having low heat conductivity which bisects the liquid crystal layer. CONSTITUTION:A liquid crystal layer is divided to two layers 4, 5 by a central sheet 3 disposed roughly at the center between a pair of glass substrates 1 and 2. Plural Y electrodes 6, 7 are provided on the inside surfaces of 1, 2 and plural X electrodes 8, 9 are provided on both surfaces of 3. The same electrical signal is impressed on the X, Y electrodes in the same position of both layers, in driving. The liquid crystals on the respective X electrodes are successively made into a light scattering state and are accumulated by the operation of impressing successively voltage pulses at both terminals of the X electrodes to X1 X2 ... Xn to heat quickly the liquid crystals in contact with the electrodes then removing the voltage and cooling quickly the liquid crystals. If a data signal is impressed to the Y electrodes in the stage of scanning the X electrodes, the liquid crystal at an optional intersected point of X-Y is held transparent.

Description

【発明の詳細な説明】 本発明は、液晶の電気・熱・光学効果を利用した熱書込
型の・液晶表示装置（以下ＬＣＤと略す）幹↓びその駆
動方法に係わる。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal writing type liquid crystal display (hereinafter abbreviated as LCD) that utilizes the electrical, thermal, and optical effects of liquid crystal and a method for driving the same.

熱書込型ＬＯＤは、液晶を加熱・冷却した時に生じる光
学的変化を主原理とするもので、これ迄は主に加熱方法
としてレーザ線の照射が用いられて−た。し、かじ、レ
ーザ照射方法では装置が大きくなシ、平面型ディスプレ
イには使用できない為、最近では、液晶パネル内のヒー
ター電極群に順次電流パルスを与えて液晶を電極ライン
毎に順次加熱する電極加熱走査方式を用いる熱書込型平
面ＬＣＤの開発が進められている。この電極加熱走査方
式熱書込型平面ＬＣＤは、既に一部実用化されている電
界印加のみＫよる電界書込型ドツトマトリクスＬＣＤに
おけるり四ストークの問題を原理的に持た力いので、大
容量ドツトマトリクス型ディスプレイに適している。又
、メモリー効果を有しているので、静止画像表示の場合
は平均電力消費は小さくてよい長所も有する。Thermal writing type LOD is based on the optical change that occurs when liquid crystal is heated and cooled, and until now, laser beam irradiation has been used as the main heating method. However, since the laser irradiation method requires a large device and cannot be used for flat displays, recently, electrodes have been developed that sequentially apply current pulses to a group of heater electrodes in the liquid crystal panel to heat the liquid crystal one electrode line at a time. The development of a thermal writing type flat LCD using a heating scanning method is progressing. This electrode-heated scanning type thermal writing type flat LCD fundamentally overcomes the four-stroke problem of the electric field writing type dot matrix LCD that relies only on electric field application, which has already been partially put into practical use, so it has a large capacity. Suitable for dot matrix type displays. Furthermore, since it has a memory effect, it has the advantage that average power consumption is small when displaying still images.

一般に、ドツトマトリクス型ＬＣＤの場合、第１図に示
すように、一方のガラス基板１にＸ電極２、他方のガラ
ス基板３ＫＹ電極４が付設され、これらは直交する様に
即ちＸ−Ｙマトリクス状に配置されており、両基板３，
４の間に液晶５が充填されている。熱書込型の場合には
、一般ＫＸ。Generally, in the case of a dot matrix type LCD, as shown in FIG. 1, an X electrode 2 is attached to one glass substrate 1, and an KY electrode 4 is attached to the other glass substrate 3, and these electrodes are arranged orthogonally to each other, that is, in an X-Y matrix shape. Both boards 3,
4 is filled with liquid crystal 5. For thermal writing type, general KX.

Ｙ電極のうち、どちらか一方が加熱用電極を兼ねる。例
えば、Ｘ電極２が加熱用兼行電極、Ｘ電極４が列電極と
すると、Ｘ電極２には順次電流パルスが印加され、Ｘ電
極およびその近傍の液晶は順次、「加熱→冷却、１を受
け１行“が選択される。One of the Y electrodes also serves as a heating electrode. For example, if the X electrode 2 is used as a row electrode for heating and the X electrode 4 is used as a column electrode, current pulses are sequentially applied to the X electrode 2, and the Row 1 is selected.

さらに冷却プロセス時における行・列電極間画素液晶へ
の電界印加の有無により７列”が選択され、合わせて行
列間画素が選択される。この時の液晶の挙動および光学
的特性は、使用する液晶の種類（スメクチック、コレス
テリック、ネマチック）および基板表面への液晶分子配
向処理方法（垂直配向、平行配向、混成配向等）あるい
は液晶への二色性色素の添加等によって異なるが、一般
に電界印加画素は透明、電界印加無しの画素は光散乱あ
るいは光吸収状態となる。ここで重要なことは、加熱お
よび冷却速度である。上記した画素選択を行うためには
冷却速度は十分に早くなければならず、一般に数十ｍ５
ｅｃ以下が必要である。この為には、必要以上に昇温し
ないこと、および必要以外の部分、例えば行電極部位以
外の液晶およびガラス基板への加熱を極力抑制する必要
がある。ここで、特に重要なことは、ガラス基板への加
熱である。ガラス基板は、熱伝導率が液晶より大きく、
且つ厚さも１ｍ程度以上と厚いため、液晶と同時に加熱
され液晶の昇温時間を長くすると共に、冷却速度をも遅
くする。従って、液晶パネルめ設計に穐々の制約を受け
、画像書込速度をあまり早くすることができない、余分
な電力消費が生じる等の欠点を引き起こしていた。Furthermore, the 7th column is selected depending on whether or not an electric field is applied to the pixel liquid crystal between the row and column electrodes during the cooling process, and the pixels between the rows and columns are also selected.The behavior and optical characteristics of the liquid crystal at this time are It varies depending on the type of liquid crystal (smectic, cholesteric, nematic), the method of aligning liquid crystal molecules on the substrate surface (vertical alignment, parallel alignment, hybrid alignment, etc.), the addition of dichroic dye to the liquid crystal, etc., but in general, electric field application pixels is transparent, and a pixel without an electric field applied is in a light scattering or light absorption state.What is important here is the heating and cooling rate.In order to perform the above pixel selection, the cooling rate must be sufficiently fast. Generally several tens of meters5
ec or lower is required. For this purpose, it is necessary not to raise the temperature more than necessary, and to suppress heating of parts other than necessary, such as the liquid crystal and glass substrate other than the row electrode parts, as much as possible. What is particularly important here is the heating of the glass substrate. Glass substrates have higher thermal conductivity than liquid crystals,
Moreover, since it is thick, about 1 m or more, it is heated at the same time as the liquid crystal, prolonging the temperature rise time of the liquid crystal, and slowing down the cooling rate. Therefore, the design of the liquid crystal panel is severely restricted, resulting in disadvantages such as the image writing speed cannot be increased very much and excessive power consumption occurs.

本発明の目的は、上記した欠点を改善した書込速度が早
く、消費電力が小さい熱書込型のＬＯＤおよびその駆動
方法を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide a thermal writing type LOD that improves the above-mentioned drawbacks, has a high writing speed, and consumes little power, and a method for driving the same.

次に１一実施例を用いて本発明忙ついて詳□しく説明す
る。Next, the present invention will be explained in detail using eleven embodiments.

第２図は、本発明一実施例のＸ−Ｙマトリクス□型表示
パネルの構造を示す模型的断面略図である。FIG. 2 is a schematic cross-sectional view showing the structure of an X-Y matrix square display panel according to an embodiment of the present invention.

液晶１層は、一対のガラス基板１，２に挾オれＪ゛かつ
側基板１，２間のほぼ中央に配置された樹脂製の中央薄
板３により２つの層４および５に分けられている。前記
基板１，２の内面には直線状かつ同方向に増化インジウ
ムの如き透明導電体による複数のＸ電極６，７が付設さ
れており、中央薄□板３の両面には直線状かつ同方向に
やはり酸化インジウムの如き透明導電体による複数のＸ
電極８゜９が付設されている。両層におけるＸ電極８．
９およびＸ電極６．７の形状および位置は観視者１２か
も見てほぼ一致している。両液界層４，５の厚さは、ス
ペーサー１０によりほぼ一定であシ、数μｍ乃至ｚＯμ
ｍ程度である。表示パネルの周囲は、エポキシ樹脂等の
接着剤１１で気密封止されている。One layer of liquid crystal is sandwiched between a pair of glass substrates 1 and 2, and is divided into two layers 4 and 5 by a central thin plate 3 made of resin, which is placed approximately in the center between the side substrates 1 and 2. . A plurality of X electrodes 6, 7 made of a transparent conductor such as enriched indium are attached to the inner surfaces of the substrates 1 and 2 in a straight line and in the same direction, and on both sides of the central thin square plate 3, a plurality of X electrodes 6 and 7 are attached in a straight line and in the same direction. In the direction, a plurality of X
An electrode 8°9 is attached. X electrode in both layers8.
The shapes and positions of the electrodes 9 and 6.7 are almost the same as viewed by the viewer 12. The thickness of both liquid interface layers 4 and 5 is approximately constant due to the spacer 10, and is in the range of several μm to zOμ.
It is about m. The periphery of the display panel is hermetically sealed with an adhesive 11 such as epoxy resin.

このパネルに用いる液晶は、一般に熱書込型ＬＯＤに使
用されるものであればスメクチック型、コレステリック
型、ネマチック型あるいはこれらの二色性色素を添加し
たゲスト−ホスト型等のいずれでも利用可能であるが、
本実施例では最も代表的なスメクチック型を用いる。液
晶材料は４−シアノ−４′−ｎ−オクチルビフェニルヲ
用いたが、他のスメクチック液晶材料あるいはこれらの
混合物あるいはスメクチック液晶材料とコレステリック
液晶材料またはネマチック液晶材料との混合物も利用で
きる。The liquid crystal used in this panel can be of the smectic type, cholesteric type, nematic type, or guest-host type with these dichroic dyes added, as long as it is generally used for thermal writing type LOD. Yes, but
In this embodiment, the most typical smectic type is used. Although 4-cyano-4'-n-octylbiphenyl was used as the liquid crystal material, other smectic liquid crystal materials or mixtures thereof, or mixtures of smectic liquid crystal materials and cholesteric liquid crystal materials or nematic liquid crystal materials can also be used.

両基板１．２および中央薄板３の液晶に接する表面には
、液晶分子を特定の形姉配向させる表面配向処理を施す
が、通常のＬＯＤに用いられる垂直配肉処理、平行配向
処理、斜方配向処理あるいはこれらの組合せを利用でき
るが、本実施例ではシラン系表面活性剤塗布による垂直
配向処理を施している。The surfaces of both substrates 1.2 and the central thin plate 3 that are in contact with the liquid crystal are subjected to a surface alignment treatment that orients the liquid crystal molecules in a specific shape. Although alignment treatment or a combination thereof can be used, in this example, vertical alignment treatment is performed by applying a silane-based surfactant.

スペーサー１０は、通常のＬＯＤにも用いられるガラス
ファイバー、ポリマーシート片あるいは基板１，２およ
び中央薄板３表面にスクリーン印刷で付着させた微小樹
脂片等を利用できるが、こコテｔｆ　直径１０μｍ程度
のガラスファイバー片ヲ用いた。The spacer 10 can be made of glass fiber, a polymer sheet piece, or a minute resin piece attached to the surfaces of the substrates 1, 2 and the central thin plate 3 by screen printing, which are also used in ordinary LOD. A piece of glass fiber was used.

中央薄板３は、透明導電体を付設・加工（パターンエツ
チング）できる樹脂、例えばポリエステル等を利用でき
、ここでは厚さ５０μｍのテトロン（余人ＫＫ製）を用
いている。The central thin plate 3 can be made of a resin that can be attached and processed (pattern etched) with a transparent conductor, such as polyester, and here, Tetron (manufactured by Yojin KK) with a thickness of 50 μm is used.

上記構成の表示パネルの液晶は、平常は均一に透明であ
るが、次の様な駆動を行うこと釦より任意のＸ−Ｙ交点
画素を光散乱白濁状態とすることができる。The liquid crystal of the display panel configured as described above is normally uniformly transparent, but by using the following drive button, any X-Y intersection pixel can be made into a light-scattering, cloudy state.

第３図は、駆動方法を説明する為のパネル正面略図であ
り、同図上のＸ電極は中央薄板３の両面における同一位
置の電極を、一方Ｙ電極は両基板１．２における同一位
置の電極を一体化して表わしである。実際の駆動におい
ても、両層同一位置のＸ、Ｘ電極には原則として同一の
電気信号を印加する。Ｘ、Ｙ電極数ｍ、ｎは、本実施例
では各々８，４０である。FIG. 3 is a schematic front view of the panel for explaining the driving method. The X electrodes in the figure are located at the same position on both sides of the central thin plate 3, while the Y electrodes are located at the same position on both substrates 1.2. The electrodes are shown integrated. In actual driving, the same electric signal is applied to the X and X electrodes at the same position in both layers in principle. The numbers m and n of the X and Y electrodes are 8 and 40, respectively, in this example.

先ず、中央薄板上のＸ電極の両端に数十Ｖ程度の電圧パ
ルスをＸ、→Ｘ、→・・・→Ｘｎと第４図に示すように
順次印加する。各電極に対する最適印加時間Ｔは電極の
形状、抵抗に応じて異なり１〜１００ｍ５ｅｃ程度であ
るが、ｋるべく短い方が前述した過剰加熱を防ぎ、かつ
書込時間を短縮するためにも望ましいので、印加電圧と
共に調整する。First, voltage pulses of about several tens of volts are sequentially applied to both ends of the X electrode on the central thin plate in the order of X, →X, →...→Xn, as shown in FIG. The optimum application time T for each electrode varies depending on the shape and resistance of the electrode, and is about 1 to 100 m5ec, but it is desirable to keep it as short as possible in order to prevent the above-mentioned excessive heating and shorten the writing time. , adjusted together with the applied voltage.

この様に、Ｘ電極に電流を流して電極に接する液晶を急
加熱し、続いて電圧を除去して液晶を急冷する操作によ
り、各Ｘ電極上の両層の液晶は順次光散乱白濁状態とな
り蓄積される。このＸ電極走査時に、Ｘ電極にデータ信
号を印加すれば、任意のＸ−Ｙ交点画素の液晶は透明の
ままＫしておくことができる。すなわち任意の画像パタ
ーンを書込むことができる。具体的には、各Ｘ電極の走
査電圧パルス印加が終了した直後の期間１３に直流もし
くは交流の電圧信号を、液晶を透明なままにしておく画
素のＸ電極に印加すればよい。このデータ、信萼電圧の
大きさはＩＯＶ程度、印加時間はＸ電極走査時ｒｎｌ　
Ｔとほぼ同じでおい。また、このデータ信号電圧の大き
さを加減することによ゛り中間調表示もできる。このよ
うに、表示パネル内の両液高層に同時に同様の電圧信号
を与えて駆動した結果、単液晶層の従来表示パネルを従
来の通常駆動法で行った場合と比べて、書込時間（約２
０′ｍ　ｓｅｃ　／本）、消費電力（約０．５　Ｗ　）
とも約半分であった。In this way, by applying a current to the X electrode to rapidly heat the liquid crystal in contact with the electrode, and then removing the voltage to rapidly cool the liquid crystal, the liquid crystal in both layers on each X electrode sequentially becomes a light-scattering cloudy state. Accumulated. If a data signal is applied to the X electrode during this X electrode scanning, the liquid crystal of any X-Y intersection pixel can be kept transparent. That is, any image pattern can be written. Specifically, a DC or AC voltage signal may be applied to the X electrode of the pixel whose liquid crystal remains transparent during period 13 immediately after the application of the scanning voltage pulse to each X electrode ends. In this data, the magnitude of the calyx voltage is about IOV, and the application time is rnl when scanning the X electrode.
It's almost the same as T. Further, by adjusting the magnitude of this data signal voltage, it is possible to display halftones. As a result of driving the display panel by simultaneously applying the same voltage signal to both liquid layers in the display panel, the writing time (approx. 2
0'm sec/piece), power consumption (approximately 0.5 W)
Both were about half.

このように１本発明による熱書込型の液晶表示装置が、
書、込時間が短く消費電力も小さい理由は、（１）　　
液晶層を２分割し、各々専用のヒーター電極で駆動し、
且つヒーターが液晶全体層のほぼ中央にある為、加熱が
早い、 （２）　　ヒーター電極が厚いガラス基板に接しておら
ず、低伝導率が小さく且つ薄い樹脂薄板上に付設されて
いる為、ヒーター電極部外への余分の加熱・昇温か少な
く、また自然冷却速度が早い、こと等にある。In this way, one thermal writing type liquid crystal display device according to the present invention has the following features:
The reasons for short write and write times and low power consumption are (1)
The liquid crystal layer is divided into two parts, each driven by a dedicated heater electrode,
Moreover, since the heater is located almost in the center of the entire liquid crystal layer, heating is fast. This is due to the fact that there is little extra heating/rising temperature to the outside of the electrode part, and the natural cooling rate is fast.

以上、詳しく説明したように、本発明液晶表示装置およ
びその駆動方法は従来の熱書込型液晶表示装置の主要な
欠点である書込速度および消費電力を大幅に散着したも
のであり、工業的価値が極めて高いものである。As explained in detail above, the liquid crystal display device and the driving method of the present invention greatly improve the writing speed and power consumption, which are the main drawbacks of the conventional thermal writing type liquid crystal display device, and are suitable for industrial use. It is of extremely high value.

なお、本発明を実施するに当っては、上記一実施例で述
べられた仕様に限定されず、種々の変形が可能であるこ
とは言うまでもない。It goes without saying that the present invention is not limited to the specifications described in the above-mentioned embodiment, and that various modifications can be made.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は、Ｘ−Ｙマトリクス型ＬＣＤの一般的構造を示
す図、第２図は本発明一実施例の構造を示す模型的断面
略図、第３図は本発明一実施例の駆動方法を説明する為
の電極図、第４図は本発明一実施例の駆動信号を示す図
である。 第２図において、”１．２・・・ガラス基板、３・・・
中央薄板、４，５・・・液晶層、６，７・・・電極、８
，９・・・電極、１０・・・スペーサー、１１・・−接
着剤、である。 第２図 ・　　第３図 Ｘ電極FIG. 1 is a diagram showing the general structure of an X-Y matrix type LCD, FIG. 2 is a schematic cross-sectional view showing the structure of an embodiment of the present invention, and FIG. 3 is a diagram showing a driving method of an embodiment of the present invention. FIG. 4 is an electrode diagram for explanation, and is a diagram showing a drive signal according to an embodiment of the present invention. In FIG. 2, "1.2...Glass substrate, 3...
Central thin plate, 4, 5... Liquid crystal layer, 6, 7... Electrode, 8
, 9...electrode, 10...spacer, 11...-adhesive. Figure 2/Figure 3 X electrode

Claims (1)

【特許請求の範囲】[Claims] （１）一対の電極基板で液晶を挾んだ液晶パネルに加熱
用電極を有し液晶の電気・熱・光学効果を利用する液晶
表示装置において、前記一対の電極基板間のほぼ中央に
、加熱用電極を両面に付設した中央薄板を配置し、且つ
前記一対の電極基板における各電極基板の電極形状と位
置が前記中央薄板を対称面として面対称の関係にあり、
前記中央薄板両面の電極形状と位置が観視者側から見て
ほぼ重なり合って見えるように配置したことを特徴とす
る液晶表示装置。　　・（２）液晶を挾む一対の電極基
板間に、加熱用電極を両面に付設した中央薄板を配置し
、前記各電極基板の電極形状と位置が前記中央薄板を対
称面として面対称の関係にあ）、前記中央薄板両面の電
極形状と位置が観視者側から見てほぼ重、クシ合って見
えるように、配置した液晶表示装置の駆動方法において
、前記中央薄板の同一位置、にある両面の電極に、はぼ
同一の加熱用走査電圧パルスを順次印加し、前記一対の
基板電極と、各々相対向する中央薄板加熱用電極との間
に、前記走査電圧パルスの印加後データ信号電圧を順次
に前記走査電圧パルス印加時間とほぼ同じ時間印加９す
ることを特徴とする駆動方法。(1) In a liquid crystal display device that has a heating electrode on a liquid crystal panel sandwiching a liquid crystal between a pair of electrode substrates and utilizes the electric, thermal, and optical effects of the liquid crystal, a heating electrode is placed approximately in the center between the pair of electrode substrates. a central thin plate with electrodes attached on both sides, and the electrode shape and position of each electrode substrate in the pair of electrode substrates are in a plane symmetrical relationship with the central thin plate as a plane of symmetry,
A liquid crystal display device characterized in that the shapes and positions of the electrodes on both sides of the central thin plate are arranged so that they appear to substantially overlap when viewed from the viewer's side.・(2) A central thin plate with heating electrodes attached on both sides is arranged between a pair of electrode substrates sandwiching the liquid crystal, and the electrode shape and position of each electrode substrate are plane symmetrical with respect to the central thin plate as a plane of symmetry. (2), in a driving method of a liquid crystal display device arranged so that the electrode shapes and positions on both sides of the central thin plate appear to overlap and overlap when viewed from the viewer, the electrodes are located at the same position on the central thin plate. Approximately the same scanning voltage pulse for heating is sequentially applied to the electrodes on both sides, and a data signal voltage is applied between the pair of substrate electrodes and the center thin plate heating electrode facing each other after the application of the scanning voltage pulse. A driving method characterized in that the voltage pulses are sequentially applied for approximately the same time as the scanning voltage pulse application time.