JPH055894A - Ferroelectric liquid crystal display element - Google Patents
Ferroelectric liquid crystal display elementInfo
- Publication number
- JPH055894A JPH055894A JP15663391A JP15663391A JPH055894A JP H055894 A JPH055894 A JP H055894A JP 15663391 A JP15663391 A JP 15663391A JP 15663391 A JP15663391 A JP 15663391A JP H055894 A JPH055894 A JP H055894A
- Authority
- JP
- Japan
- Prior art keywords
- liquid crystal
- divided
- electrode
- pixel
- electrodes
- 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.)
- Pending
Links
Landscapes
- Liquid Crystal (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、強誘電性液晶表示素子
に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ferroelectric liquid crystal display device.
【０００２】[0002]
【従来の技術】強誘電性液晶表示素子は、強誘電性液晶
の双安定性を利用したもので、強誘電性液晶は、そのし
きい値電界以上の電界を印加すると、液晶分子が一方向
に配向して電界の印加を断った後もこの配向状態を保
ち、また、上記電界と逆方向でかつ液晶のしきい値電界
以上の電界を印加すると、液晶分子が前の配向方向に対
してほぼ４５°回動した方向に配向して電界の印加を断
った後もこの配向状態を保つ。2. Description of the Related Art Ferroelectric liquid crystal display elements utilize the bistability of ferroelectric liquid crystals. Ferroelectric liquid crystal displays liquid crystal molecules in one direction when an electric field above the threshold electric field is applied. This alignment state is maintained even after the application of the electric field is stopped after the liquid crystal molecules are oriented in the same direction, and when an electric field in the opposite direction to the above electric field and above the threshold electric field of the liquid crystal is applied, the liquid crystal molecules are oriented in the previous alignment direction. This orientation state is maintained even after the application of the electric field is stopped by orienting in the direction rotated by about 45 °.
【０００３】ところで、上記強誘電性液晶表示素子は、
液晶分子がその双安定性により上記２つの配向方向のい
ずれかに配向するため、その中間の状態に液晶分子を配
向させることができないので、画素の明るさの度合を変
える階調表示が困難であった。By the way, the above ferroelectric liquid crystal display device is
Since the liquid crystal molecules are aligned in either of the above two orientation directions due to their bistability, it is impossible to align the liquid crystal molecules in the intermediate state, so that it is difficult to perform gradation display that changes the degree of brightness of pixels. there were.
【０００４】そこで、従来から、強誘電性液晶表示素子
の階調表示を実現することが検討されており、その手段
としては、フレーム階調方式と、面積階調方式とが考え
られている。Therefore, it has been conventionally considered to realize gradation display of a ferroelectric liquid crystal display element, and as a means therefor, a frame gradation method and an area gradation method have been considered.
【０００５】上記フレーム階調方式は、１画面分の画像
を複数フレームで表示するもので、同じ画素部に印加す
る電界が全フレームにおいて同じであるときは、最初の
フレームでの印加電界によりいずれかの方向に配向した
液晶分子がその配向状態を最終フレームまで維持して、
上記画素部に最大明度または最小明度（黒）の画素が表
示されるが、各フレームでの印加電界の方向を変える
と、その都度液晶分子の配向状態が反転し、上記画素部
に表示される画素が、一方向の電界を印加するフレーム
数と他方向の電界を印加するフレーム数との比に応じた
階調の画素として見える。（Ｐroceeding Ｅurodisplay
1984 Ｄigest(1984) Ｐ73参照）The frame gray scale method displays an image for one screen in a plurality of frames. When the electric field applied to the same pixel portion is the same in all frames, the electric field applied in the first frame will eventually cause the problem. Liquid crystal molecules oriented in that direction maintain their alignment state until the final frame,
Pixels of maximum brightness or minimum brightness (black) are displayed in the pixel section, but when the direction of the applied electric field in each frame is changed, the alignment state of the liquid crystal molecules is inverted each time and displayed in the pixel section. The pixel appears as a pixel having a gray scale corresponding to the ratio of the number of frames to which an electric field in one direction is applied and the number of frames to which an electric field in another direction is applied. (Proceeding Eurodisplay
1984 Digest (1984) See P73)
【０００６】しかし、このフレーム階調方式は、１画面
分の画像を複数フレームで表示するものであるため、１
画面分の画像を表示するのに、１フレームでの２値表示
に比べて階調数倍（フレーム数倍）の時間が必要であ
り、したがって、テレビジョン画像等のような動画像の
表示特性が極端に低下するし、また表示時間を短くする
ために各フレームの周波数を高くしたのでは、液晶の応
答性の関係で表示に“ちらつき”が発生するという問題
をもっている。However, since this frame gradation method displays an image for one screen in a plurality of frames,
Displaying an image for a screen requires time that is several times as many gradations (number of frames) as compared with binary display in one frame. Therefore, display characteristics of moving images such as television images are required. However, if the frequency of each frame is increased in order to shorten the display time, "flicker" may occur in the display due to the response of the liquid crystal.
【０００７】一方、上記１つの画素部内で、液晶分子が
一方向に配向する領域の面積と他方向に配向する領域の
面積とを変化させて、この各領域の面積比に応じた階調
の画素を表示するもので、この面積階調方式としては、
従来、電極分割による方式と、しきい値電界差による方
式とが提案されている。On the other hand, the area of the region in which the liquid crystal molecules are oriented in one direction and the area of the region in which the liquid crystal molecules are oriented in the other direction are changed in the one pixel portion, and the gradation is adjusted according to the area ratio of the respective regions. It displays pixels, and this area gradation method
Conventionally, a method based on electrode division and a method based on a threshold electric field difference have been proposed.
【０００８】上記電極分割による面積階調方式は、液晶
層をはさんで対向する一対の透明基板の一方に形成する
各画素電極をそれぞれ複数の電極に分割し、この各分割
電極と他方の基板に形成した対向電極との間にそれぞれ
印加する電界の方向を制御することによって階調表示を
行なうもので、各分割電極に対応する各分割画素部に同
じ方向の電界を印加すると、全ての分割画素部の液晶分
子が同じ方向に配向して、最大明度または最小明度の画
素が表示され、各分割画素部に印加する電界の方向を変
えると、各分割画素部の液晶分子がそれぞれ印加電界の
方向に応じて配向して、表示画素が、一方向の電界を印
加した分割画素部の数と他方向の電界を印加した分割画
素部の数との比に応じた階調の画素として見える。In the area gradation method based on the above-mentioned electrode division, each pixel electrode formed on one of a pair of transparent substrates facing each other across the liquid crystal layer is divided into a plurality of electrodes, and the divided electrodes and the other substrate are divided. Gradation display is performed by controlling the direction of the electric field applied between the divided electrodes and the opposing electrodes formed on the same. When the electric field in the same direction is applied to each divided pixel portion corresponding to each divided electrode, all divided areas are divided. When the liquid crystal molecules in the pixel section are aligned in the same direction to display the pixel with the maximum brightness or the minimum brightness, and when the direction of the electric field applied to each divided pixel section is changed, the liquid crystal molecules in each divided pixel section respectively change the applied electric field. Oriented according to the direction, the display pixel appears as a pixel having a gradation according to the ratio of the number of divided pixel portions to which an electric field in one direction is applied and the number of divided pixel portions to which an electric field in the other direction is applied.
【０００９】また、上記しきい値電界差による面積階調
方式は、各画素部の電極（画素電極または対向電極）上
の絶縁膜の厚さまたは液晶層の層厚を連続的または段階
的に変えることによって画素部の各領域の液晶のしきい
値電界に差をもたせ、印加電界の強さを制御して階調表
示を行なうもので、印加電界を強くするのにともなって
液晶分子の配向状態が反転する領域が広がり、表示画素
が、液晶分子が一方向に配向している領域と他方向に配
向している領域との面積比に応じた階調の画素となる。
（特開昭61−166590号公報、特開昭62−145216号公報参
照）In the area gray scale method based on the threshold electric field difference, the thickness of the insulating film or the liquid crystal layer on the electrode (pixel electrode or counter electrode) of each pixel portion is continuously or stepwise adjusted. By changing the threshold electric field of the liquid crystal in each area of the pixel section, the intensity of the applied electric field is controlled to perform gradation display. The region in which the state is reversed spreads, and the display pixel becomes a pixel having a gradation corresponding to the area ratio between the region in which the liquid crystal molecules are aligned in one direction and the region in which the liquid crystal molecules are aligned in the other direction.
(See JP-A-61-166590 and JP-A-62-145216)
【００１０】これら面積階調方式は、いずれも、１画面
分の画像を１フレームで表示するものであるため、前述
したフレーム階調方式のように、動画像の表示特性が極
端に低下したり、表示に“ちらつき”が発生するという
問題はない。In each of these area gradation methods, an image for one screen is displayed in one frame, so that the display characteristics of moving images are extremely deteriorated as in the frame gradation method described above. , There is no problem that "flicker" occurs in the display.
【００１１】[0011]
【発明が解決しようとする課題】しかしながら、上記電
極分割による面積階調方式は、各画素電極をそれぞれ複
数の電極に分割して、この各分割電極と対向電極との間
にそれぞれ印加する電界の方向を制御するものであるた
め、１つの画素電極列ごとに、画素電極の分割数と同数
の信号ラインを配線しなければならず、したがって、信
号ライン数が非常に多くなってその配線が面倒になる
し、また駆動回路も複雑になるという問題をもってい
た。However, in the area gradation method based on the above-mentioned electrode division, each pixel electrode is divided into a plurality of electrodes, and the electric field applied between each divided electrode and the counter electrode is reduced. Since the direction is controlled, it is necessary to wire the same number of signal lines as the number of pixel electrode divisions for each pixel electrode column. Therefore, the number of signal lines is very large and the wiring is troublesome. In addition, the driving circuit becomes complicated.
【００１２】一方、上記しきい値電界差による面積階調
方式は、１つの画素電極列ごとに配線する信号ライン数
はそれぞれ１本でよく、また駆動回路も無階調表示の場
合の駆動回路に電圧制御部を付加するだけの比較的簡単
な回路でよい。On the other hand, in the area gray scale method based on the threshold electric field difference, one signal line may be provided for each pixel electrode column, and the drive circuit is also a drive circuit in the case of non-gradation display. A relatively simple circuit, in which only a voltage control unit is added, is sufficient.
【００１３】しかし、このしきい値電界差による面積階
調方式は、各画素部の電極上の絶縁膜の厚さまたは液晶
層の層厚を連続的または段階的に変えることによって画
素部の各領域の液晶のしきい値電界に差をもたせたもの
であるため、液晶表示素子を製造する際に、電極上に形
成する絶縁膜の厚さや、電極の表面高さ等を精密に制御
しなければならず、したがって、液晶表示素子の製造が
非常に難しくなってしまうという問題をもっている。However, in the area gradation method based on the threshold electric field difference, the thickness of the insulating film on the electrode of each pixel portion or the layer thickness of the liquid crystal layer is continuously or stepwise changed so that each pixel portion of the pixel portion is changed. Since the threshold electric field of the liquid crystal in the area is made different, the thickness of the insulating film formed on the electrode and the surface height of the electrode must be precisely controlled when manufacturing the liquid crystal display element. Therefore, there is a problem that manufacturing of the liquid crystal display device becomes very difficult.
【００１４】本発明の目的は、信号ライン数を増加させ
ることなく、かつ比較的簡単な駆動回路で面積階調方式
による階調表示を行なうことができ、しかも製造も容易
な強誘電性液晶表示素子を提供することにある。An object of the present invention is to provide a ferroelectric liquid crystal display which is capable of performing gray scale display by an area gray scale method with a relatively simple driving circuit without increasing the number of signal lines and is easy to manufacture. It is to provide an element.
【００１５】[0015]
【課題を解決するための手段】本発明の強誘電性液晶表
示素子は、液晶層をはさんで対向する一対の透明基板の
一方に多数本の対向電極を互いに平行に形成し、他方の
基板には、前記対向電極の長さ方向に対して直交する多
数本の信号ラインと、この各信号ラインにそれぞれ接続
されて前記対向電極と対向する多数の画素電極を形成す
るとともに、前記画素電極は、複数の分割電極と、この
各分割電極をつなぐ高抵抗の接続部とで構成して、その
１つの分割電極を前記信号ラインに接続したことを特徴
とするものである。In a ferroelectric liquid crystal display device of the present invention, a large number of counter electrodes are formed in parallel on one of a pair of transparent substrates facing each other with a liquid crystal layer in between, and the other substrate. A plurality of signal lines that are orthogonal to the length direction of the counter electrode, and a plurality of pixel electrodes that are respectively connected to the signal lines and face the counter electrode are formed. It is characterized in that it is composed of a plurality of divided electrodes and a high resistance connecting portion connecting each divided electrode, and one of the divided electrodes is connected to the signal line.
【００１６】[0016]
【作用】すなわち、本発明の強誘電性液晶表示素子は、
画素電極の各分割電極のうち、信号ラインに接続した分
割電極には、信号ラインからの駆動電圧を印加し、他の
分割電極には上記高抵抗の接続部によって電圧降下した
電圧を印加することにより、各分割電極に対応する各分
割画素部に印加される電界の強さに差をもたせて面積階
調方式による階調表示を行なうものであり、各分割画素
部に表示される分割画素の集まりで表示される画素の階
調は、液晶分子が一方向に配向している分割画素部の数
と液晶分子が他方向に配向している分割画素部の数との
比に応じた階調であるから、信号ラインに印加する駆動
電圧を制御して、液晶分子の配向状態を反転させる分割
画素部の数を選択すれば、表示画素の階調を制御するこ
とができる。In other words, the ferroelectric liquid crystal display device of the present invention is
Among the divided electrodes of the pixel electrode, the driving voltage from the signal line is applied to the divided electrode connected to the signal line, and the voltage dropped by the high resistance connecting portion is applied to the other divided electrodes. Thus, the gradation display by the area gradation method is performed by making a difference in the strength of the electric field applied to each divided pixel portion corresponding to each divided electrode. The gradation of the pixels displayed as a group depends on the ratio between the number of divided pixel portions in which liquid crystal molecules are oriented in one direction and the number of divided pixel portions in which liquid crystal molecules are oriented in the other direction. Therefore, the gradation of the display pixel can be controlled by controlling the driving voltage applied to the signal line and selecting the number of divided pixel portions that invert the alignment state of the liquid crystal molecules.
【００１７】そして、この強誘電性液晶表示素子におい
ては、画素電極の各分割電極を高抵抗の接続部によりつ
ないで、１つの分割電極だけを信号ラインに接続してい
るため、画素電極を複数の電極に分割して面積階調方式
による階調表示を行なうものでありながら、１つの画素
電極列ごとに配線する信号ライン数はそれぞれ１本でよ
く、また駆動回路も無階調表示の場合の駆動回路に電圧
制御部を付加するだけの比較的簡単な回路でよい。Further, in this ferroelectric liquid crystal display element, since each divided electrode of the pixel electrode is connected by a high resistance connecting portion and only one divided electrode is connected to the signal line, a plurality of pixel electrodes are provided. In the case of performing the gray scale display by the area gray scale method by dividing the electrodes into two electrodes, the number of signal lines to be wired for each pixel electrode column may be one, and the drive circuit may also be a gray scale display. A relatively simple circuit, in which only a voltage control unit is added to the driving circuit of FIG.
【００１８】しかも、この液晶表示素子は、画素電極の
各分割電極を高抵抗の接続部でつなぐことによって、各
分割電極に対応する各分割画素部に印加される電界の強
さに差をもたせているため、従来のしきい値電界差によ
る面積階調方式のように、各画素部の電極上の絶縁膜の
厚さまたは液晶層の層厚を変えて画素部の各領域の液晶
のしきい値電界に差をもたせる必要もない。Further, in this liquid crystal display element, the divided electrodes of the pixel electrode are connected to each other by a high resistance connecting portion so that the intensity of the electric field applied to each divided pixel portion corresponding to each divided electrode is made different. Therefore, as in the conventional area gray scale method based on the threshold electric field difference, the thickness of the insulating film on the electrode of each pixel portion or the layer thickness of the liquid crystal layer is changed to remove the liquid crystal in each region of the pixel portion. There is no need to make a difference in the threshold electric field.
【００１９】[0019]
【実施例】以下、本発明の一実施例を図１〜図３を参照
して説明する。図１は液晶表示素子の電極パターン図、
図２はその１つの画素電極の拡大図、図３は液晶表示素
子の断面図である。この実施例の強誘電性液晶表示素子
の構成を説明すると、図３において、１，２は液晶層を
はさんで対向配置される一対の透明基板（ガラス板等）
である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. Fig. 1 is an electrode pattern diagram of a liquid crystal display device,
FIG. 2 is an enlarged view of one of the pixel electrodes, and FIG. 3 is a sectional view of the liquid crystal display element. The structure of the ferroelectric liquid crystal display device of this embodiment will be described. In FIG. 3, reference numerals 1 and 2 denote a pair of transparent substrates (a glass plate or the like) which are opposed to each other with a liquid crystal layer interposed therebetween.
Is.
【００２０】上記一対の透明基板１，２のうち、一方の
基板、例えば下基板１の液晶層対向面には、多数本の透
明な対向電極３が、図１に示すように密な間隔で互いに
平行に形成されており、さらにこの下基板１の電極形成
面上には、表面に配向処理を施した配向処理絶縁膜４が
設けられている。On one surface of the pair of transparent substrates 1 and 2, for example, the lower substrate 1, on the surface facing the liquid crystal layer, a large number of transparent counter electrodes 3 are arranged at close intervals as shown in FIG. Aligned insulating films 4 are formed in parallel with each other, and the surface of the lower substrate 1 is subjected to an alignment treatment on the electrode formation surface.
【００２１】また、上基板２の液晶層対向面には、上記
下基板１面の各対向電極３の長さ方向に対して直交する
多数本の信号ライン５と、この各信号ライン５にそれぞ
れ接続されて前記各対向電極３と対向する多数の透明な
画素電極６が形成されており、さらにこの上基板２の電
極形成面上には、表面に配向処理を施した配向処理絶縁
膜８が設けられている。Further, on the surface of the upper substrate 2 facing the liquid crystal layer, a large number of signal lines 5 orthogonal to the length direction of the respective counter electrodes 3 on the surface of the lower substrate 1 and the signal lines 5 are respectively provided. A large number of transparent pixel electrodes 6 that are connected to face each of the counter electrodes 3 are formed, and further, on the electrode formation surface of the upper substrate 2, an alignment treatment insulating film 8 whose surface is subjected to an alignment treatment is formed. It is provided.
【００２２】上記画素電極６は、図１および図２に示す
ように、信号ライン５の長さ方向に対して直交する方向
に複数分割（この実施例では３分割）されており、これ
ら分割電極６ａ，６ｂ，６ｃは、高抵抗の接続部７ａ，
７ｂを介して直列につながっている。As shown in FIGS. 1 and 2, the pixel electrode 6 is divided into a plurality of portions (three divisions in this embodiment) in the direction orthogonal to the length direction of the signal line 5, and these divided electrodes are divided. 6a, 6b, 6c are high resistance connecting portions 7a,
It is connected in series via 7b.
【００２３】上記各分割電極６ａ，６ｂ，６ｃと、これ
らをつなぐ接続部７ａ，７ｂとは、ＩＴＯまたは酸化ス
ズ等からなる透明導電膜をパターニングして形成された
もので、信号ライン５側の分割電極６ａと中央の分割電
極６ｂとをつなぐ接続部７ａは、これら分割電極６ａ，
６ｂの一端側に形成され、中央の分割電極６ｂと外側の
分割電極６ｃとをつなぐ接続部７ｂは、これら分割電極
６ｂ，６ｃの他端側に形成されており、さらに、上記接
続部７ａ，７ｂはそれぞれ、その抵抗値を大きくするた
めに、極く細い幅の線状に形成されている。The divided electrodes 6a, 6b, 6c and the connecting portions 7a, 7b connecting them are formed by patterning a transparent conductive film made of ITO, tin oxide or the like, and are formed on the signal line 5 side. The connecting portion 7a connecting the divided electrode 6a and the divided electrode 6b at the center is formed by the divided electrodes 6a,
A connecting portion 7b formed on one end side of the divided electrode 6b and connecting the central divided electrode 6b and the outer divided electrode 6c is formed on the other end side of these divided electrodes 6b, 6c. Each 7b is formed in a linear shape having an extremely narrow width in order to increase its resistance value.
【００２４】また、上記信号ライン５は、クロム，ニッ
ケル，アルミニウム等の低抵抗金属で形成されており、
この信号ライン５には、上記画素電極６の各分割電極６
ａ，６ｂ，６ｃのうち、信号ライン５側の分割電極６ａ
だけがその側縁部において接続されている。The signal line 5 is made of a low resistance metal such as chromium, nickel and aluminum.
Each of the divided electrodes 6 of the pixel electrode 6 is connected to the signal line 5.
Of a, 6b, 6c, the divided electrode 6a on the signal line 5 side
Only are connected at their side edges.
【００２５】そして、上記一対の基板１，２は、図３に
示すように対向配置されて、図示しない枠状のシール材
を介して接着されており、この両基板１，２間のシール
材で囲まれた空隙には、強誘電性液晶９が封入されてい
る。なお、図３において、１０は、両基板１，２間に点
在されて両基板１，２間のセルギャップ（液晶層厚）を
規制する円柱状のギャップ材である。また、この液晶表
示素子の両面つまり両基板１，２の外面には、それぞれ
偏光板１１，１２が配置されている。The pair of substrates 1 and 2 are arranged so as to face each other as shown in FIG. 3 and are adhered to each other via a frame-shaped sealing material (not shown). Ferroelectric liquid crystal 9 is enclosed in the space surrounded by. In FIG. 3, reference numeral 10 denotes a columnar gap material that is scattered between the substrates 1 and 2 to regulate the cell gap (liquid crystal layer thickness) between the substrates 1 and 2. Polarizing plates 11 and 12 are arranged on both surfaces of the liquid crystal display element, that is, on the outer surfaces of the substrates 1 and 2, respectively.
【００２６】なお、両基板１，２面に形成した配向処理
絶縁膜４，８は互いに平行な方向に配向処理されてお
り、偏光板１１，１２は、その偏光軸（透過軸または吸
収軸）を互いにほぼ直交させて配置されている。The alignment treatment insulating films 4 and 8 formed on both surfaces of the substrates 1 and 2 are aligned in parallel to each other, and the polarizing plates 11 and 12 have their polarization axes (transmission axis or absorption axis). Are arranged substantially orthogonal to each other.
【００２７】さらに、上記偏光板１１，１２の偏光軸の
方向は、画素電極５と対向電極３と間に一方向の駆動電
界（液晶のしきい値電界以上の電界）を印加したときに
おける液晶分子の配向方向が両偏光板１１，１２の偏光
軸に対してそれぞれほぼ４５°の角度で交差し、他方向
の駆動電界を印加したときにおける液晶分子の配向方向
が一方の偏光板１１の偏光軸に対してほぼ平行（他方の
偏光板１２の偏光軸に対してはほぼ直交）になる方向に
設定されており、したがって、この液晶表示素子の各画
素部は、一方向の駆動電界の印加により光を透過させ、
他方向の駆動電界印加により光を遮断する。Further, the polarization axes of the polarizing plates 11 and 12 are liquid crystal when a driving electric field in one direction (electric field equal to or higher than the threshold electric field of liquid crystal) is applied between the pixel electrode 5 and the counter electrode 3. The orientation directions of the molecules intersect the polarization axes of both polarizing plates 11 and 12 at an angle of approximately 45 °, and the orientation direction of the liquid crystal molecules when a driving electric field in the other direction is applied is the polarization direction of one polarizing plate 11. The liquid crystal display element is set in a direction substantially parallel to the axis (substantially orthogonal to the polarization axis of the other polarizing plate 12). Therefore, each pixel portion of this liquid crystal display element is applied with a driving electric field in one direction. To transmit light,
Light is blocked by applying a driving electric field in the other direction.
【００２８】この強誘電性液晶表示素子は、下基板１の
各対向電極３に順次走査信号を印加し、これに同期させ
て上基板２の各信号ライン５に画素データに応じた駆動
電圧を印加することにより表示駆動されるもので、各信
号ライン５に印加された駆動電圧は、この信号ライン５
に接続された各画素電極６に印加される。In this ferroelectric liquid crystal display element, a scanning signal is sequentially applied to each counter electrode 3 of the lower substrate 1, and in synchronization with this, a driving voltage corresponding to pixel data is applied to each signal line 5 of the upper substrate 2. Display driving is performed by applying the voltage, and the drive voltage applied to each signal line 5 is
Is applied to each pixel electrode 6 connected to.
【００２９】そして、上記画素電極６は、複数の電極６
ａ，６ｂ，６ｃに分割されており、さらにこの各分割電
極６ａ，６ｂ，６ｃは高抵抗の接続部７ａ，７ｂを介し
て直列につながっているため、画素電極６に印加される
電圧は、その各分割電極６ａ，６ｂ，６ｃで異なる。The pixel electrode 6 is composed of a plurality of electrodes 6
Since the divided electrodes 6a, 6b, 6c are connected in series via the high resistance connecting portions 7a, 7b, the voltage applied to the pixel electrode 6 is The divided electrodes 6a, 6b, 6c are different.
【００３０】つまり、画素電極６の各分割電極６ａ，６
ｂ，６ｃのうち、信号ライン５に接続した分割電極６ａ
には、信号ライン５からの駆動電圧がそのまま印加され
るが、中央の分割電極６ｂには、信号ライン５側の分割
電極６ａの電圧が高抵抗の接続部７ａにおいて電圧降下
して印加されるため、この中央の分割電極６ｂに印加さ
れる電圧は、信号ライン５側の分割電極６ａに印加され
る電圧より低い電圧である。また、外側の分割電極６ｃ
には、中央の分割電極６ｂの電圧が高抵抗の接続部７ｂ
においてさらに電圧降下して印加されるため、この外側
の分割電極６ｃに印加される電圧は、中央の分割電極６
ｂに印加されるこの電圧よりさらに低い電圧である。That is, the divided electrodes 6a, 6 of the pixel electrode 6 are
Of b and 6c, the divided electrode 6a connected to the signal line 5
, The driving voltage from the signal line 5 is applied as it is, but the voltage of the divided electrode 6a on the signal line 5 side is applied to the central divided electrode 6b with a voltage drop at the high resistance connection portion 7a. Therefore, the voltage applied to the central divided electrode 6b is lower than the voltage applied to the divided electrode 6a on the signal line 5 side. In addition, the outer divided electrode 6c
The voltage of the divided electrode 6b at the center has a high resistance.
The voltage applied to the outer divided electrode 6c is lower than that of the central divided electrode 6c.
It is a voltage lower than this voltage applied to b.
【００３１】なお、上記各分割電極６ａ，６ｂ，６ｃと
接続部７ａ，７ｂは、単位面積当りの抵抗値が比較的高
いＩＴＯまたは酸化スズ等からなる透明導電膜で形成さ
れており、この透明導電膜はその幅を狭くして抵抗値を
比較的高くしてあるため、中央の分割電極６ｂおよび外
側の分割電極６ｃに印加される電圧は、信号ライン５側
の分割電極６ａおよび中央の分割電極６ｂにおいても電
圧降下した電圧である。The divided electrodes 6a, 6b, 6c and the connecting portions 7a, 7b are formed of a transparent conductive film made of ITO or tin oxide having a relatively high resistance value per unit area. Since the conductive film has a narrow width and a relatively high resistance value, the voltage applied to the central divided electrode 6b and the outer divided electrode 6c is the same as the divided electrode 6a on the signal line 5 side and the central divided electrode 6a. The voltage also drops at the electrode 6b.
【００３２】したがって、この強誘電性液晶表示素子に
よれば、各分割電極６ａ，６ｂ，６ｃに対応する各分割
画素部に印加される電界の強さに差をもたせて、面積階
調方式による階調表示を行なうことができる。Therefore, according to this ferroelectric liquid crystal display element, the area gray scale method is applied by making the strength of the electric field applied to each divided pixel portion corresponding to each divided electrode 6a, 6b, 6c different. Gradation display can be performed.
【００３３】すなわち、信号ライン５に印加する駆動電
圧が液晶のしきい値電圧を僅かに上回る程度であれば、
１つの画素部の各分割画素部のうち、信号ライン５に接
続した分割電極６ａに対応する分割画素部だけで液晶分
子の配向状態が反転するだけであるが、信号ライン５に
印加する駆動電圧を上げて行くと、高抵抗接続部７ａに
おいて電圧降下した電圧を印加される中央の分割電極６
ｂに対応する分割画素部の印加電界も液晶のしきい値電
界に達して、この分割画素部の液晶分子配向状態も反転
する。That is, if the drive voltage applied to the signal line 5 is slightly higher than the threshold voltage of the liquid crystal,
Of the divided pixel portions of one pixel portion, only the divided pixel portion corresponding to the divided electrode 6a connected to the signal line 5 reverses the alignment state of the liquid crystal molecules, but the drive voltage applied to the signal line 5 When the voltage is increased, the central divided electrode 6 to which the voltage dropped in the high resistance connecting portion 7a is applied.
The applied electric field of the divided pixel portion corresponding to b also reaches the threshold electric field of the liquid crystal, and the liquid crystal molecule alignment state of this divided pixel portion is also inverted.
【００３４】また、さらに信号ライン５に印加する駆動
電圧を上げて行くと、高抵抗接続部７ａおよび７ｂにお
いて電圧降下した電圧を印加される外側の分割電極６ｃ
に対応する分割画素部の印加電界も液晶のしきい値電界
に達して、この分割画素部の液晶分子配向状態も反転す
る。Further, when the driving voltage applied to the signal line 5 is further increased, the outer divided electrode 6c to which the voltage dropped in the high resistance connecting portions 7a and 7b is applied.
The applied electric field of the divided pixel portion corresponding to (3) also reaches the threshold electric field of the liquid crystal, and the liquid crystal molecule alignment state of the divided pixel portion is also inverted.
【００３５】そして、各分割画素部に表示される分割画
素の集まりで表示される画素の階調は、液晶分子が一方
向に配向している分割画素部の数と液晶分子が他方向に
配向している分割画素部の数との比に応じた階調である
から、信号ライン５に印加する駆動電圧を制御して、液
晶分子の配向状態を反転させる分割画素部の数を選択す
れば、表示画素の階調を制御することができる。The gradation of a pixel displayed by a group of divided pixels displayed in each divided pixel portion is the number of divided pixel portions in which liquid crystal molecules are aligned in one direction and the liquid crystal molecules are aligned in the other direction. Since the gradation is in accordance with the ratio of the number of divided pixel portions that are being operated, it is possible to control the drive voltage applied to the signal line 5 and select the number of divided pixel portions that invert the alignment state of the liquid crystal molecules. The gradation of the display pixel can be controlled.
【００３６】すなわち、例えば白黒の２色表示におい
て、各分割画素部に表示される分割画素が、液晶分子が
その双安定性による２つの配向方向のうち一方の配向方
向に配向したときに白、他の方向に配向したときに黒と
なるとした場合、各分割画素部の液晶分子が全て一方の
配向方向に配向していれば、各分割画素部に表示される
分割画素はいずれも白であり、してがってこれら分割画
素の集まりで表示される画素も白である。That is, for example, in a two-color display of black and white, when the divided pixels displayed in each divided pixel portion are white when the liquid crystal molecules are aligned in one of two alignment directions due to the bistability, If the liquid crystal molecules in each divided pixel portion are all oriented in one orientation direction when the liquid crystal molecules are black when oriented in the other direction, all the divided pixels displayed in each divided pixel portion are white. Therefore, the pixels displayed by the group of these divided pixels are also white.
【００３７】そして、この状態で、信号ライン５に液晶
分子の配向状態を反転させる逆方向電界を印加する場
合、この逆方向電界として、上記各分割画素部のうち信
号ライン５側の分割画素部だけに液晶のしきい値以上の
電界が作用する強さの電界を印加すると、信号ライン５
側の分割画素だけが黒となり、他の２つの画素は白のま
まであるため、各分割画素の集まりで表示される画素
は、黒１：白２の比率の階調の灰色画素となる。Then, in this state, when a reverse electric field for reversing the alignment state of the liquid crystal molecules is applied to the signal line 5, as the reverse electric field, the divided pixel section on the signal line 5 side among the divided pixel sections is applied. When an electric field of a strength above which the electric field exceeds the liquid crystal threshold value is applied, the signal line 5
Since only the divided pixel on the side is black and the other two pixels are still white, the pixel displayed by the group of each divided pixel is a gray pixel having a gradation of black1: white2.
【００３８】また、上記逆方向電界として、信号ライン
５側の分割画素部と中央の分割画素部とに液晶のしきい
値以上の電界が作用する強さの電界を印加すると、信号
ライン５側と中央との２つの分割画素が黒となり、外側
の画素は白のままであるため、表示画素は、黒２：白１
の比率の階調の灰色画素となる。When an electric field having a strength above the threshold of liquid crystal acts on the divided pixel portion on the signal line 5 side and the central divided pixel portion as the reverse electric field, the signal line 5 side is applied. Since the two divided pixels, that is, the central pixel and the central pixel, are black and the outer pixels remain white, the display pixels are black 2: white 1
It becomes a gray pixel of the gradation of the ratio.
【００３９】さらに、上記逆方向電界として、全ての分
割画素部に液晶のしきい値以上の電界が作用する強さの
逆方向電界を印加すると、全ての分割画素が黒となり、
表示画素が黒になる。Further, when a reverse electric field having a strength such that an electric field equal to or higher than the threshold value of the liquid crystal acts on all the divided pixel portions as the reverse electric field, all the divided pixels become black,
Display pixels turn black.
【００４０】そして、上記強誘電性液晶表示素子におい
ては、画素電極６の各分割電極６ａ，６ｂ，６ｃを高抵
抗の接続部７ａ，７ｂでつないで、１つの分割電極６ａ
だけを信号ライン５に接続しているため、画素電極を複
数の電極に分割して面積階調方式による階調表示を行な
うものでありながら、１つの画素電極列ごとに配線する
信号ライン数はそれぞれ１本でよく、また駆動回路も無
階調表示の場合の駆動回路に電圧制御部を付加するだけ
の比較的簡単な回路でよい。In the ferroelectric liquid crystal display device, the divided electrodes 6a, 6b, 6c of the pixel electrode 6 are connected by the high resistance connecting portions 7a, 7b to form one divided electrode 6a.
Since only one of them is connected to the signal line 5, the pixel electrode is divided into a plurality of electrodes to perform the gradation display by the area gradation method, but the number of signal lines wired for each pixel electrode column is The number of each driving circuit may be one, and the driving circuit may be a relatively simple circuit in which a voltage control unit is added to the driving circuit in the case of non-gradation display.
【００４１】したがって、この強誘電性液晶表示素子に
よれば、信号ライン数を増加させることなく、かつ比較
的簡単な駆動回路で面積階調方式による階調表示を行な
うことができる。Therefore, according to this ferroelectric liquid crystal display element, it is possible to perform the gradation display by the area gradation method without increasing the number of signal lines and with a relatively simple driving circuit.
【００４２】しかも、この強誘電性液晶表示素子は、画
素電極６の各分割電極６ａ，６ｂ，６ｃを高抵抗の接続
部７ａ，７ｂでつなぐことによって、各分割電極６ａ，
６ｂ，６ｃに対応する各分割画素部に印加される電界の
強さに差をもたせているため、従来のしきい値電界差に
よる面積階調方式のように、各画素部の電極上の絶縁膜
の厚さまたは液晶層の層厚を変えて画素部の各領域の液
晶のしきい値電界に差をもたせる必要もなく、したがっ
て液晶表示素子の製造も容易である。次に、本発明の他
の実施例を説明する。図４は、本発明の他の実施例を示
す液晶表示素子の断面図である。Moreover, in this ferroelectric liquid crystal display element, the divided electrodes 6a, 6b, 6c of the pixel electrode 6 are connected by the high resistance connecting portions 7a, 7b, so that the divided electrodes 6a, 6b
Since there is a difference in the strength of the electric field applied to each divided pixel portion corresponding to 6b and 6c, the insulation on the electrodes of each pixel portion is different from that in the conventional area gradation method by the threshold electric field difference. It is not necessary to change the thickness of the film or the thickness of the liquid crystal layer to give a difference in the threshold electric field of the liquid crystal in each region of the pixel portion, and therefore the manufacture of the liquid crystal display device is easy. Next, another embodiment of the present invention will be described. FIG. 4 is a sectional view of a liquid crystal display device showing another embodiment of the present invention.
【００４３】この実施例の強誘電性液晶表示素子は、信
号ライン５を各画素電極６の列間に設けて、この信号ラ
イン５を画素電極列間からの漏光を防ぐ遮光マスクとし
ても利用するとともに、画素電極５の各分割電極６ａ，
６ｂ，６ｃ間に対応する部分にもこの部分からの漏光を
防ぐ遮光マスク１３を設けたものである。なお、上記遮
光マスク１３は、信号ライン５と同じ金属膜で形成され
ている。In the ferroelectric liquid crystal display element of this embodiment, the signal line 5 is provided between the columns of the pixel electrodes 6, and the signal line 5 is also used as a light-shielding mask for preventing light leakage between the pixel electrode columns. At the same time, the divided electrodes 6a of the pixel electrode 5,
A light-shielding mask 13 for preventing light leakage from this portion is also provided in a portion corresponding to between 6b and 6c. The light-shielding mask 13 is formed of the same metal film as the signal line 5.
【００４４】この信号ライン５および遮光マスク１３
は、基板２面に形成されており、画素電極６は、信号ラ
イン５および遮光マスク１３の形成面上に設けた透明絶
縁膜１４の上に形成されている。The signal line 5 and the light shielding mask 13
Are formed on the surface of the substrate 2, and the pixel electrodes 6 are formed on the transparent insulating film 14 provided on the surface on which the signal lines 5 and the light shielding mask 13 are formed.
【００４５】上記画素電極６は、図２に示した画素電極
と同じもので、その信号ライン５側の分割電極６ａは、
上記透明絶縁膜１４に設けたコンタクト孔において信号
ライン５に接続されている。The pixel electrode 6 is the same as the pixel electrode shown in FIG. 2, and the divided electrode 6a on the signal line 5 side is
The signal line 5 is connected through a contact hole formed in the transparent insulating film 14.
【００４６】なお、この実施例の液晶表示素子は、上述
した構成を除けば、その構成は図１〜図３に示した実施
例実施例と同じであるから、その説明は図に同符号を付
して省略する。The liquid crystal display element of this embodiment has the same structure as that of the embodiment shown in FIGS. 1 to 3 except for the above-mentioned structure, and therefore the same reference numerals are used in the drawings. Attached and omitted.
【００４７】また、上記実施例では、画素電極６を、図
２に示したように信号ライン５の長さ方向に対して直交
する方向に分割しているが、この画素電極６は、図５に
示すように、信号ライン５の長さ方向に分割してもよ
い。Further, in the above embodiment, the pixel electrode 6 is divided in the direction orthogonal to the length direction of the signal line 5 as shown in FIG. As shown in, the signal line 5 may be divided in the length direction.
【００４８】さらに、上記実施例では、画素電極６の各
分割電極６ａ，６ｂ，６ｃをつなぐ接続部７ａ，７ｂ
を、極く細い幅の線状に形成しているが、各分割電極６
ａ，６ｂ，６ｃおよび接続部７ａ，７ｂを単位面積当り
の抵抗値がより高い透明導電膜で形成するとともに、上
記接続部７ａ，７ｂの幅を十分狭くすれば、上記接続部
７ａ，７ｂの長さは図６に示すように短くてもよい。ま
た、画素電極６の分割数は、２分割以上であれば何分割
でもよく、画素電極６の分割数を多くすれば、多段階の
階調表示が可能である。Further, in the above embodiment, the connection portions 7a, 7b for connecting the divided electrodes 6a, 6b, 6c of the pixel electrode 6 to each other.
Is formed in a line shape having an extremely thin width, but each divided electrode 6
If the a, 6b, 6c and the connecting portions 7a, 7b are formed of a transparent conductive film having a higher resistance value per unit area, and the width of the connecting portions 7a, 7b is sufficiently narrowed, the connecting portions 7a, 7b can be The length may be short, as shown in FIG. Further, the number of divisions of the pixel electrode 6 may be any number as long as it is two or more, and if the number of divisions of the pixel electrode 6 is increased, multi-step gradation display is possible.
【００４９】[0049]
【発明の効果】本発明の強誘電性液晶表示素子は、画素
電極を複数の電極に分割するとともに、この各分割電極
を高抵抗の接続部でつなぎ、その１つの分割電極を信号
ラインに接続したものであるから、信号ライン数を増加
させることなく、かつ比較的簡単な駆動回路で面積階調
方式による階調表示を行なうことができるし、またその
製造も容易である。According to the ferroelectric liquid crystal display element of the present invention, the pixel electrode is divided into a plurality of electrodes, each divided electrode is connected by a high resistance connecting portion, and one of the divided electrodes is connected to the signal line. Therefore, it is possible to perform gray scale display by the area gray scale method with a relatively simple driving circuit without increasing the number of signal lines, and the manufacturing thereof is easy.
【図１】本発明の一実施例を示す液晶表示素子の電極パ
ターン図。FIG. 1 is an electrode pattern diagram of a liquid crystal display element showing an embodiment of the present invention.
【図２】１つの画素電極の拡大図。FIG. 2 is an enlarged view of one pixel electrode.
【図３】液晶表示素子の断面図である。FIG. 3 is a cross-sectional view of a liquid crystal display element.
【図４】本発明の他の実施例を示す液晶表示素子の断面
図。FIG. 4 is a sectional view of a liquid crystal display element showing another embodiment of the present invention.
【図５】画素電極の変形例を示す図。FIG. 5 is a diagram showing a modified example of a pixel electrode.
【図６】画素電極の他の変形例を示す図。FIG. 6 is a diagram showing another modification of the pixel electrode.
１，２…透明基板、３…対向電極、４…配向処理絶縁
膜、５…信号ライン、６…画素電極、６ａ，６ｂ，６ｃ
…分割電極、７ａ，７ｂ…接続部、８……配向処理絶縁
膜、９…強誘電性液晶、１０…ギャップ材、１１，１２
…偏光板、１３…遮光マスク、１４…透明絶縁膜。1, 2 ... Transparent substrate, 3 ... Counter electrode, 4 ... Alignment insulating film, 5 ... Signal line, 6 ... Pixel electrode, 6a, 6b, 6c
... split electrodes, 7a, 7b ... connection part, 8 ... orientation-treated insulating film, 9 ... ferroelectric liquid crystal, 10 ... gap material, 11, 12
... Polarizing plate, 13 ... Shading mask, 14 ... Transparent insulating film.
Claims (1)
いて、液晶層をはさんで対向する一対の透明基板の一方
に多数本の対向電極を互いに平行に形成し、他方の基板
には、前記対向電極の長さ方向に対して直交する多数本
の信号ラインと、この各信号ラインにそれぞれ接続され
て前記対向電極と対向する多数の画素電極を形成すると
ともに、前記画素電極は、複数の分割電極と、この各分
割電極をつなぐ高抵抗の接続部とで構成して、その１つ
の分割電極を前記信号ラインに接続したことを特徴とす
る強誘電性液晶表示素子。Claim: What is claimed is: 1. In a liquid crystal display device using a ferroelectric liquid crystal, a large number of counter electrodes are formed in parallel with each other on one of a pair of transparent substrates facing each other with a liquid crystal layer in between, and the other one. On the substrate, a plurality of signal lines that are orthogonal to the length direction of the counter electrode and a plurality of pixel electrodes that are respectively connected to the signal lines and face the counter electrode are formed. The ferroelectric liquid crystal display element is characterized in that the electrode is composed of a plurality of divided electrodes and a high resistance connecting portion connecting the divided electrodes, and one of the divided electrodes is connected to the signal line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15663391A JPH055894A (en) | 1991-06-27 | 1991-06-27 | Ferroelectric liquid crystal display element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15663391A JPH055894A (en) | 1991-06-27 | 1991-06-27 | Ferroelectric liquid crystal display element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH055894A true JPH055894A (en) | 1993-01-14 |
Family
ID=15631944
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15663391A Pending JPH055894A (en) | 1991-06-27 | 1991-06-27 | Ferroelectric liquid crystal display element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH055894A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6291031B1 (en) | 1998-01-27 | 2001-09-18 | Matsushita Electric Industrial Co., Ltd. | Method for preparing optical recording medium and preparation apparatus therefor |
-
1991
- 1991-06-27 JP JP15663391A patent/JPH055894A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6291031B1 (en) | 1998-01-27 | 2001-09-18 | Matsushita Electric Industrial Co., Ltd. | Method for preparing optical recording medium and preparation apparatus therefor |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4773737A (en) | Color display panel | |
| US5899550A (en) | Display device having different arrangements of larger and smaller sub-color pixels | |
| KR101210887B1 (en) | Liquid Crystal Display Device and Driving Method Thereof | |
| JPH08179341A (en) | Liquid crystal display device and its driving method | |
| US7834833B2 (en) | Liquid crystal display device selectable between wide view angle display and narrow view angle display and liquid crystal display apparatus using same | |
| KR20040023535A (en) | Active matrix typed liquid crystal display device with vertical alignment and method for driving the same | |
| KR101157975B1 (en) | Method For Driving Liquid Crystal Display Device | |
| JPH08254712A (en) | Liquid crystal display element | |
| KR100936949B1 (en) | Liquid crystal display device including color filter | |
| KR100324457B1 (en) | Active matrix liquid crystal display device | |
| US6072555A (en) | Display apparatus capable of gradational display | |
| JPH04247431A (en) | Display device | |
| JPH10301141A (en) | Liquid crystal display element and its production | |
| JPS61282823A (en) | Liquid crystal panel for color television | |
| JPH0815714A (en) | Liquid crystal display element | |
| JPH055894A (en) | Ferroelectric liquid crystal display element | |
| JP3363731B2 (en) | Display device capable of gradation display | |
| JP2580603B2 (en) | Liquid crystal display | |
| JPH07104283A (en) | Color liquid crystal display device | |
| JPH075432A (en) | Liquid crystal display device | |
| JP2519712B2 (en) | Liquid crystal display | |
| JP2001075073A (en) | Method for driving liquid crystal display device with wide viewing angle | |
| JP3397828B2 (en) | Liquid crystal display | |
| JPH06347816A (en) | Liquid crystal display element | |
| JPS63228124A (en) | Liquid crystal electrooptic device |