JP2002040426A - Liquid crystal display device - Google Patents
Liquid crystal display deviceInfo
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- JP2002040426A JP2002040426A JP2000223535A JP2000223535A JP2002040426A JP 2002040426 A JP2002040426 A JP 2002040426A JP 2000223535 A JP2000223535 A JP 2000223535A JP 2000223535 A JP2000223535 A JP 2000223535A JP 2002040426 A JP2002040426 A JP 2002040426A
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- liquid crystal
- cell
- display device
- crystal display
- temperature
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】この発明は、温度変化による
コントラストの低下を液晶材料の特性を利用して改善し
たＤ−ＳＴＮ方式の液晶表示装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a D-STN type liquid crystal display device in which a decrease in contrast due to a change in temperature is improved by utilizing characteristics of a liquid crystal material.
【０００２】[0002]
【従来の技術】パソコン、テレビ、デジタルカメラなど
の液晶ディスプレイとしてＳＴＮ（ｓｕｐｅｒ ｔｗｉ
ｓｔｅｄ ｎｅｍａｔｉｃ）方式の液晶表示装置（ＳＴ
Ｎ−ＬＣＤ）を改良したＤ（ｄｏｕｂｌｅ ｌａｙｅｒ
ｅｄ）−ＳＴＮ方式の液晶表示装置が広く知られてい
る。2. Description of the Related Art STN (super twin) is used as a liquid crystal display for personal computers, televisions, digital cameras and the like.
liquid crystal display device (ST nematic)
D (double layer) with improved N-LCD
ed) -STN type liquid crystal display devices are widely known.
【０００３】この液晶表示装置（Ｄ−ＳＴＮ−ＬＣＤ）
は、ＳＴＮ−ＬＣＤの欠点であった背影の色付きを防止
して白黒表示させることができる。図６はＤ−ＳＴＮ−
ＬＣＤを示す概略構成図で、図示するように、駆動用の
ＳＴＮ（駆動セル）１０と補償用のＳＴＮ（補償セル）
２０との２層型の液晶表示装置となっている。This liquid crystal display device (D-STN-LCD)
Can prevent the back shadow from being colored, which is a drawback of the STN-LCD, and display the image in black and white. FIG. 6 shows D-STN-
FIG. 1 is a schematic configuration diagram showing an LCD, as shown, a drive STN (drive cell) 10 and a compensation STN (compensation cell).
20 is a two-layer type liquid crystal display device.
【０００４】なお、この図において、１１、１２は駆動
セル１０のガラス基板、１３は駆動セル１０の液晶を示
し、２１、２２は補償セル２０のガラス基板、２３は補
償セル２０の液晶を示す。また、１４は入射光側の偏光
板、２４は出射光側の偏光板を示す。In this figure, reference numerals 11 and 12 denote glass substrates of the driving cell 10, 13 denotes a liquid crystal of the driving cell 10, 21 and 22 denote glass substrates of the compensating cell 20, and 23 denotes a liquid crystal of the compensating cell 20. . Reference numeral 14 denotes a polarizing plate on the incident light side, and 24 denotes a polarizing plate on the outgoing light side.
【０００５】そして、このＤ−ＳＴＮ−ＬＣＤの駆動セ
ル１０と補償セル２０は、液晶分子のツイスト方向が逆
となっているが、その他の構成と条件（ツイスト角、プ
レティルト角、液晶材料、液晶の複屈折率（Δｎ）、セ
ル厚（ｄ）など）は全て同じものとなっている。また、
液晶分子のツイスト方向は液晶に添加するカイラル材で
規定され、ツイスト角は１６０〜２７０度程度となって
いる。In the D-STN-LCD, the driving cell 10 and the compensating cell 20 have opposite twist directions of liquid crystal molecules, but have other configurations and conditions (twist angle, pretilt angle, liquid crystal material, liquid crystal, Have the same birefringence (Δn) and cell thickness (d). Also,
The twist direction of the liquid crystal molecules is defined by a chiral material added to the liquid crystal, and the twist angle is about 160 to 270 degrees.
【０００６】このように構成されているＤ−ＳＴＮ−Ｌ
ＣＤは、入射偏光が駆動セル１０の複屈折効果によって
生ずる干渉現象（色付きはこの干渉によって生ずる）を
ツイスト方向が逆向きの補償セル２０により補償し、背
影の色付きの問題を解決している。[0006] The D-STN-L configured as described above
In the CD, the interference phenomenon (coloring is caused by this interference) caused by the birefringence effect of the driving cell 10 due to the incident polarized light is compensated by the compensating cell 20 in which the twist direction is reversed, and the background coloring problem is solved.
【０００７】このように、Ｄ−ＳＴＮ−ＬＣＤは色付き
のない白黒表示が可能であるが、ＯＦＦ電圧が温度上昇
に伴って低下するため、コントラスト比も低下する。As described above, the D-STN-LCD can perform monochrome display without coloring, but the contrast ratio also decreases because the OFF voltage decreases as the temperature rises.
【０００８】図７はＤ−ＳＴＮ−ＬＣＤにおいて最大コ
ントラスト比が得られるＯＦＦ電圧の温度依存性を示す
が、このようにＯＦＦ電圧が温度上昇にしたがって低下
する。これは、液晶の弾性定数と誘電率の異方性が温度
上昇にしたがって小さくなるためで、液晶材料の物性に
よるものである。FIG. 7 shows the temperature dependence of the OFF voltage at which the maximum contrast ratio is obtained in the D-STN-LCD, and the OFF voltage decreases as the temperature increases. This is because the anisotropy of the elastic constant and the dielectric constant of the liquid crystal decreases as the temperature increases, and is due to the physical properties of the liquid crystal material.
【０００９】したがって、Ｄ−ＳＴＮ−ＬＣＤの駆動回
路には温度補償回路が付加されており、この温度補償回
路が駆動電圧を温度にしたがって変化させ、ＯＦＦ電圧
の低下によるコントラスト比の低下を防止するようにな
っている。なお、温度補償回路は一般にサ−ミスタを用
いて構成されている。Therefore, a temperature compensating circuit is added to the driving circuit of the D-STN-LCD, and this temperature compensating circuit changes the driving voltage according to the temperature, thereby preventing a decrease in the contrast ratio due to a decrease in the OFF voltage. It has become. Incidentally, the temperature compensation circuit is generally constituted by using a thermistor.
【００１０】[0010]
【発明が解決しようとする課題】上記したように、従来
のＤ−ＳＴＮ−ＬＣＤは駆動回路に温度補償回路を備え
るために、それだけコスト高の製品となる。また、サ−
ミスタの温度感応のバラツキやＬＣＤセル部分とサ−ミ
スタ部分の温度差などのために、駆動電圧を高精度に温
度補償することができず、コントラスト比の低下を招く
と言う問題があった。As described above, since the conventional D-STN-LCD has a temperature compensation circuit in the driving circuit, it becomes a product with a higher cost. In addition,
Due to variations in the temperature response of the mister and the temperature difference between the LCD cell part and the thermistor part, there is a problem that the drive voltage cannot be temperature-compensated with high accuracy and the contrast ratio decreases.
【００１１】そこで本発明では、温度補償回路などを備
えることなく、液晶材料の特性を利用して高コントラス
トを得ることができるＤ−ＳＴＮ−ＬＣＤを提供するこ
とを目的とする。Accordingly, an object of the present invention is to provide a D-STN-LCD capable of obtaining a high contrast by using the characteristics of a liquid crystal material without providing a temperature compensation circuit or the like.
【００１２】[0012]
【課題を解決するための手段】上記した目的を達成する
ため、本発明は、第１の発明として、駆動セルと補償セ
ルとを有するＤ−ＳＴＮ方式の液晶表示装置において、
駆動セルの液晶と補償セルの液晶とを異なる液晶材料で
形成し、温度変化に対して高いコントラストを得る構成
としたことを特徴とする液晶表示装置を提案する。According to a first aspect of the present invention, there is provided a D-STN type liquid crystal display device having a driving cell and a compensation cell.
A liquid crystal display device characterized in that the liquid crystal of the driving cell and the liquid crystal of the compensation cell are formed of different liquid crystal materials to obtain a high contrast with respect to a temperature change.
【００１３】第２の発明として、駆動セルと補償セルと
を有するＤ−ＳＴＮ方式の液晶表示装置において、補償
セルの液晶は、駆動セルの液晶に対して、室温付近では
同じ複屈折率を持ち、室温より温度上昇するにしたがい
複屈折率が低下する液晶材料で形成し、温度変化に対し
て高いコントラストを得る構成としたことを特徴とする
液晶表示装置を提案する。As a second invention, in a D-STN type liquid crystal display device having a driving cell and a compensation cell, the liquid crystal of the compensation cell has the same birefringence as the liquid crystal of the driving cell near room temperature. The present invention proposes a liquid crystal display device characterized in that the liquid crystal display device is formed of a liquid crystal material whose birefringence decreases as the temperature rises from room temperature to obtain a high contrast with respect to a temperature change.
【００１４】第３の発明として、駆動セルと補償セルと
を有するＤ−ＳＴＮ方式の液晶表示装置において、補償
セルの液晶は、駆動セルの液晶に対して、室温付近では
同じ複屈折率を持ち、ネマティック相から等方相への相
転移温度が低い液晶材料で形成し、温度変化に対して高
いコントラストを得る構成としたことを特徴とする液晶
表示装置を提案する。As a third invention, in a D-STN type liquid crystal display device having a driving cell and a compensation cell, the liquid crystal of the compensation cell has the same birefringence as the liquid crystal of the driving cell near room temperature. The present invention proposes a liquid crystal display device formed of a liquid crystal material having a low phase transition temperature from a nematic phase to an isotropic phase, and configured to obtain high contrast with respect to a temperature change.
【００１５】[0015]
【発明の実施の形態】次に、本発明の実施形態について
図面に沿って説明する。図１は本発明の実施形態を示す
液晶表示装置（Ｄ−ＳＴＮ−ＬＣＤ）の概略構成図であ
る。Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a liquid crystal display device (D-STN-LCD) showing an embodiment of the present invention.
【００１６】この図において、３０は駆動セルで、３
１、３２は駆動セルのガラス基板、３３は駆動セルの液
晶を示し、また、４０は補償セルで、４１、４２は補償
セルのガラス基板、４３は補償セルの液晶を示す。さら
に、３４は入射光側の偏光板、４４は出射光側の偏光板
である。In this figure, reference numeral 30 denotes a driving cell;
Reference numerals 1 and 32 denote glass substrates of the driving cell, 33 denotes a liquid crystal of the driving cell, 40 denotes a compensation cell, 41 and 42 denote glass substrates of the compensation cell, and 43 denotes a liquid crystal of the compensation cell. Further, 34 is a polarizing plate on the incident light side, and 44 is a polarizing plate on the outgoing light side.
【００１７】本実施形態のＤ−ＳＴＮ−ＬＣＤは、駆動
セル３０の液晶３３と補償セル４０の液晶４３とを異な
る液晶材料で形成したことが特徴となっており、駆動セ
ル３０と補償セル４０のその他構成と条件については従
来例同様に同じものとなっている。The D-STN-LCD of this embodiment is characterized in that the liquid crystal 33 of the driving cell 30 and the liquid crystal 43 of the compensation cell 40 are formed of different liquid crystal materials. Other configurations and conditions are the same as in the conventional example.
【００１８】駆動セル３０の液晶３３と補償セル４０の
液晶４３とは上記したように異なる液晶材料で形成して
ある。液晶３３、４３は室温付近で同じ複屈折率とな
り、温度上昇するにしたがって液晶４３の複屈折率が液
晶３３の複屈折率より低下する液晶材料で形成してあ
る。The liquid crystal 33 of the drive cell 30 and the liquid crystal 43 of the compensation cell 40 are formed of different liquid crystal materials as described above. The liquid crystals 33 and 43 have the same birefringence near room temperature, and are formed of a liquid crystal material in which the birefringence of the liquid crystal 43 becomes lower than the birefringence of the liquid crystal 33 as the temperature rises.
【００１９】このように構成することにより、温度上昇
した環境においても駆動電圧を変えないで、最大コント
ラストとなるＯＦＦ電圧を室温と同様に設定することが
できる。この結果、温度上昇した場合にもＯＦＦ電圧が
低下しないから、高コントラストの白黒表示が可能にな
る。With this configuration, the OFF voltage at which the maximum contrast is obtained can be set in the same manner as at room temperature without changing the drive voltage even in an environment where the temperature has risen. As a result, even when the temperature rises, the OFF voltage does not decrease, so that a high-contrast monochrome display is possible.
【００２０】なお、液晶３３、４３を上記のように形成
するには、例えば、室温付近でのこれら液晶３３、４３
の複屈折率が同じで、ネマテック相から等方相への相転
移温度（ＴＮＩ）が液晶３３に対し液晶４３を低くする
液晶材料を用いることにより実現することができる。In order to form the liquid crystals 33, 43 as described above, for example, these liquid crystals 33, 43 near room temperature are used.
Can be realized by using a liquid crystal material having the same birefringence and a phase transition temperature (T NI ) from a nematic phase to an isotropic phase that makes the liquid crystal 43 lower than the liquid crystal 33.
【００２１】次に、本発明を具体的に実施した一実施例
について従来例と比較しながら説明する。 「従来例」 ・駆動セル １）基板：透明電極付きガラス基板 ２）配向膜：日立化成製配向膜 ＬＱ−１８００ プレ
ティルト角６度 ３）ラビング：レ−ヨン製ラビング布使用 ４）ツイスト角：２４０°左ツイスト ５）セル厚：６．０μｍ ６）液晶：メルク製液晶 △ｎ＝０．１５（２５℃）
ＴＮＩ＝１０５℃カイラル材としてメルク製Ｓ−８１１
を０．８ｗｔ％ 添加（左ツイスト） ・補償セル １）基板：ガラス基板（透明電極無し） ２）配向膜：日立化成製配向膜 ＬＱ−１８００ プレ
ティルト角６度 ３）ラビング：レ−ヨン製ラビング布使用 ４）ツイスト角：２４０°右ツイスト ５）セル厚：６．０μｍ ６）液晶：メルク製液晶 △ｎ＝０．１５（２５℃）
ＴＮＩ＝１０５℃カイラル材としてメルク製Ｓ−８１１
を０．８ｗｔ％ 添加（右ツイスト） ・両セルの重ね合わせ 両セルの対峙する液晶分子が直交 ・偏光板 １）偏光板：日東電工製Ｇ−１２２０ ２）偏光板貼り角度：直交ニコル配置で、駆動セル外側
のラビング方向と駆動セル側の偏光板透過軸のなす角度
が４５度になるように配置Next, an embodiment of the present invention will be described in comparison with a conventional example. "Conventional example" ・ Drive cell 1) Substrate: Glass substrate with transparent electrode 2) Alignment film: Alignment film made by Hitachi Chemical LQ-1800 Pretilt angle 6 degrees 3) Rubbing: Use of rubbing cloth made of rayon 4) Twist angle: 240 ° Left twist 5) Cell thickness: 6.0 μm 6) Liquid crystal: Merck liquid crystal △ n = 0.15 (25 ° C)
T NI = 105 ° C S-811 manufactured by Merck as a chiral material
1 wt.% (Left twist) ・ Compensation cell 1) Substrate: glass substrate (no transparent electrode) 2) Alignment film: Hitachi Chemical alignment film LQ-1800 Pretilt angle 6 degrees 3) Rubbing: Rayon rubbing Use of cloth 4) Twist angle: 240 ° right twist 5) Cell thickness: 6.0 μm 6) Liquid crystal: Merck liquid crystal △ n = 0.15 (25 ° C.)
T NI = 105 ° C S-811 manufactured by Merck as a chiral material
0.8 wt% (right twist) ・ Superposition of both cells Liquid crystal molecules facing each other are orthogonal ・ Polarizer 1) Polarizer: G-1220 made by Nitto Denko 2) Polarizer sticking angle: orthogonal Nicol arrangement Are arranged so that the angle between the rubbing direction outside the driving cell and the transmission axis of the polarizing plate on the driving cell side is 45 degrees.
【００２２】「実施例」 ・駆動セル １）基板：透明電極付きガラス基板 ２）配向膜：日立化成製配向膜 ＬＱ−１８００ プレ
ティルト角６度 ３）ラビング：レ−ヨン製ラビング布使用 ４）ツイスト角：２４０°左ツイスト ５）セル厚：６．０μｍ ６）液晶：メルク製液晶 △ｎ＝０．１５（２５℃）
ＴＮＩ＝１０５℃カイラル材としてメルク製Ｓ−８１１
を０．８ｗｔ％ 添加（左ツイスト） ・補償セル １）基板：ガラス基板（透明電極無し） ２）配向膜：日立化成製配向膜 ＬＱ−１８００ プレ
ティルト角６度 ３）ラビング：レ−ヨン製ラビング布使用 ４）ツイスト角：２４０°右ツイスト ５）セル厚：６．０μｍ ６）液晶：メルク製液晶 △ｎ＝０．１５（２５℃）
ＴＮＩ＝９４℃カイラル材としてメルク製Ｒ−８１１を
０．８ｗｔ％ 添加（右ツイスト） ・両セルの重ね合わせ 両セルの対峙する液晶分子が直交 ・偏光板 １）偏光板：日東電工製Ｇ−１２２０ ２）偏光板貼り角度：直交ニコル配置で、駆動セル外側
のラビング方向と駆動セル側の偏光板透過軸のなす角度
が４５度になるように配置[Examples] ・ Drive cell 1) Substrate: glass substrate with transparent electrode 2) Alignment film: Alignment film made by Hitachi Chemical LQ-1800 Pretilt angle 6 degrees 3) Rubbing: Use of rubbing cloth made of rayon 4) Twist Angle: 240 ° left twist 5) Cell thickness: 6.0 μm 6) Liquid crystal: Merck liquid crystal Δn = 0.15 (25 ° C.)
T NI = 105 ° C S-811 manufactured by Merck as a chiral material
1 wt.% (Left twist) ・ Compensation cell 1) Substrate: glass substrate (no transparent electrode) 2) Alignment film: Hitachi Chemical alignment film LQ-1800 Pretilt angle 6 degrees 3) Rubbing: Rayon rubbing Use of cloth 4) Twist angle: 240 ° right twist 5) Cell thickness: 6.0 μm 6) Liquid crystal: Merck liquid crystal △ n = 0.15 (25 ° C.)
TNI = 94 ° C. 0.8 wt% of R-811 manufactured by Merck was added as a chiral material (right twist). ・ Superposition of both cells. The liquid crystal molecules facing each other were orthogonal. ・ Polarizer 1) Polarizer: Nitto Denko G -1220 2) Polarizing plate sticking angle: Arranged so that the angle between the rubbing direction outside the driving cell and the transmission axis of the polarizing plate on the driving cell side is 45 degrees in the orthogonal Nicol arrangement.
【００２３】図２は上記した従来例と実施例のコントラ
スト比の温度依存性を示す特性図である。なお、この特
性図は、Ｄ−ＳＴＮ−ＬＣＤの駆動電圧を室温で最大コ
ントラスト比を得る電圧に固定して測定したものであ
る。FIG. 2 is a characteristic diagram showing the temperature dependence of the contrast ratio between the above-described conventional example and the embodiment. Note that this characteristic diagram is obtained by fixing the drive voltage of the D-STN-LCD to a voltage at which the maximum contrast ratio is obtained at room temperature.
【００２４】この特性図から分かるように、従来例のＤ
−ＳＴＮ−ＬＣＤは高温になるにしたがってコントラス
ト比が大きく低下するが、本実施例のＤ−ＳＴＮ−ＬＣ
Ｄはコントラスト比がほとんど低下しないことが判明し
た。As can be seen from this characteristic diagram, the conventional D
-The contrast ratio of the STN-LCD greatly decreases as the temperature increases, but the D-STN-LC of the present embodiment is
D was found to have little decrease in contrast ratio.
【００２５】また、従来例と本実施例のＤ−ＳＴＮ−Ｌ
ＣＤについて、室温（２５℃）と８０℃における透過率
対電圧特性（Ｔ−Ｖ特性）を測定した。従来例のＤ−Ｓ
ＴＮ−ＬＣＤの測定結果を図３に、本実施例のＤ−ＳＴ
Ｎ−ＬＣＤの測定結果を図４に各々示す。The D-STN-L of the conventional example and the present embodiment
With respect to the CD, transmittance versus voltage characteristics (TV characteristics) at room temperature (25 ° C.) and 80 ° C. were measured. Conventional DS
FIG. 3 shows the measurement results of the TN-LCD, and FIG.
FIG. 4 shows the measurement results of the N-LCD.
【００２６】図３のＴ−Ｖ特性より分かるように、従来
例のＤ−ＳＴＮ−ＬＣＤは、透過率変化が２５℃と８０
℃とでほぼ同じ曲線で始まるが、８０℃では２５℃に比
べて低い駆動電圧で透過率変化が開始するために、室温
（２５℃）で最大コントラスト比を得る駆動電圧と同じ
駆動電圧で駆動すると、ＯＦＦ電圧での透過率が大きく
なりコントラスト比が低下する。As can be seen from the TV characteristics shown in FIG. 3, the conventional D-STN-LCD has a transmittance change of 25.degree.
Although the curve starts with the same curve at 80 ° C., at 80 ° C., the change in transmittance starts at a lower drive voltage than at 25 ° C. Then, the transmittance at the OFF voltage increases, and the contrast ratio decreases.
【００２７】図４のＴ−Ｖ特性のように、本実施例のＤ
−ＳＴＮ−ＬＣＤは、８０℃のＴ−Ｖ特性曲線が電圧上
昇にしたがって一度減少する、いわゆるバウンドが生
じ、このバウンドの極小値付近にＯＦＦ電圧が設定され
るために、８０℃に温度上昇してもコントラスト比が低
下しないことが判明した。As shown in the TV characteristic of FIG.
In the -STN-LCD, a so-called "bound" occurs in which the TV characteristic curve at 80 [deg.] C. once decreases as the voltage rises. Since the OFF voltage is set near the minimum value of the bound, the temperature rises to 80 [deg.] C. It was found that the contrast ratio did not decrease.
【００２８】図５は本実施例のＤ−ＳＴＮ−ＬＣＤに備
えた駆動セル３０と補償セル４０の液晶３３、４３を形
成する液晶材料について、その複屈折率△ｎの温度依存
性を示した特性図である。FIG. 5 shows the temperature dependence of the birefringence Δn of the liquid crystal material forming the liquid crystals 33 and 43 of the driving cell 30 and the compensation cell 40 provided in the D-STN-LCD of this embodiment. It is a characteristic diagram.
【００２９】この特性図から分かるように、室温と室温
以下では両セルの液晶３３、４３の複屈折率がほぼ等し
いが、温度が高くなるにしたがって補償セル４０の液晶
４３の複屈折率が駆動セル３０の液晶３３の複屈折率に
対して小さくなる。As can be seen from this characteristic diagram, at room temperature and below room temperature, the birefringences of the liquid crystals 33 and 43 in both cells are substantially equal, but as the temperature increases, the birefringence of the liquid crystal 43 in the compensating cell 40 increases. It becomes smaller than the birefringence of the liquid crystal 33 of the cell 30.
【００３０】以上、本発明の実施形態と実施例について
説明したが、Ｄ−ＳＴＮ−ＬＣＤのＴ−Ｖ特性において
バウンドを生じさせるには、補償セルの複屈折率△ｎと
セル厚ｄを駆動セルの△ｎｄより小さくすればよい。The embodiments and examples of the present invention have been described above. To generate a bound in the TV characteristics of the D-STN-LCD, the birefringence Δn and the cell thickness d of the compensating cell are driven. It may be smaller than △ nd of the cell.
【００３１】したがって、本発明を実施するに際して
は、上記実施例のように、相転移温度（ＴＮＩ）が異な
る液晶材料を使用することにかぎられない。相転移温度
（ＴＮＩ）に関係なく上記のような駆動セルと補償セル
の関係を実現できるその他の液晶材料を用いて実施する
ことができる。Therefore, the present invention is not limited to using liquid crystal materials having different phase transition temperatures (T NI ) as in the above embodiment. The present invention can be implemented using another liquid crystal material capable of realizing the above-described relationship between the driving cell and the compensation cell regardless of the phase transition temperature (T NI ).
【００３２】[0032]
【発明の効果】上記した通り、本発明の液晶表示装置
は、駆動セルと補償セルの液晶を形成する液晶材料の特
性を利用し、温度上昇によるＯＦＦ電圧の低下を抑制す
る構成としたので、駆動回路に温度補償回路などを備え
ることなく、温度上昇によるコントラストの低下を防止
することができる。As described above, the liquid crystal display device of the present invention utilizes the characteristics of the liquid crystal material forming the liquid crystal of the driving cell and the compensation cell, and suppresses the decrease of the OFF voltage due to the temperature rise. Without providing a temperature compensation circuit or the like in the drive circuit, it is possible to prevent a decrease in contrast due to a rise in temperature.
【００３３】この結果、温度補償を確実に行なうことが
でき、かつ、製品のロ−コスト化に適する高コントラス
トの液晶表示装置となる。As a result, a high-contrast liquid crystal display device which can reliably perform temperature compensation and is suitable for low-cost products.
【図１】本発明の実施形態を示すＤ−ＳＴＮ−ＬＣＤの
概略構成図である。FIG. 1 is a schematic configuration diagram of a D-STN-LCD showing an embodiment of the present invention.
【図２】従来例のＤ−ＳＴＮ−ＬＣＤと本発明を実施し
たＤ−ＳＴＮ−ＬＣＤとのコントラスト比の温度依存性
を示した特性図である。FIG. 2 is a characteristic diagram showing temperature dependence of a contrast ratio between a conventional D-STN-LCD and a D-STN-LCD embodying the present invention.
【図３】室温（２５℃）と８０℃における従来例のＤ−
ＳＴＮ−ＬＣＤの透過率対電圧特性を示す特性図であ
る。FIG. 3 shows a conventional D- at room temperature (25 ° C.) and 80 ° C.
FIG. 4 is a characteristic diagram showing transmittance-voltage characteristics of an STN-LCD.
【図４】本発明を実施したＤ−ＳＴＮ−ＬＣＤの透過率
対電圧特性を示す図３同様の特性図である。FIG. 4 is a characteristic diagram similar to FIG. 3, showing transmittance versus voltage characteristics of a D-STN-LCD embodying the present invention.
【図５】本発明を実施したＤ−ＳＴＮ−ＬＣＤの駆動セ
ルと補償セルに設けた液晶が有する複屈折率の温度依存
性を示す特性図である。FIG. 5 is a characteristic diagram showing the temperature dependence of the birefringence of the liquid crystal provided in the driving cell and the compensation cell of the D-STN-LCD embodying the present invention.
【図６】従来例として示したＤ−ＳＴＮ−ＬＣＤの概略
構成図である。FIG. 6 is a schematic configuration diagram of a D-STN-LCD shown as a conventional example.
【図７】従来例のＤ−ＳＴＮ−ＬＣＤにおいて最大コン
トラスト比が得られるＯＦＦ電圧の温度依存性を示す特
性図である。FIG. 7 is a characteristic diagram showing a temperature dependence of an OFF voltage at which a maximum contrast ratio is obtained in a conventional D-STN-LCD.
３０ 駆動セル ３１、３２ ガラス基板 ３３ 液晶 ３４ 偏光板 ４０ 補償セル ４１、４２ ガラス基板 ４３ 液晶 ４４ 偏光板 Reference Signs List 30 driving cell 31, 32 glass substrate 33 liquid crystal 34 polarizing plate 40 compensation cell 41, 42 glass substrate 43 liquid crystal 44 polarizing plate
Claims (3)
Ｎ方式の液晶表示装置において、 駆動セルの液晶と補償セルの液晶とを異なる液晶材料で
形成し、 温度変化に対して高いコントラストを得る構成としたこ
とを特徴とする液晶表示装置。1. A D-ST having a driving cell and a compensation cell.
An N-type liquid crystal display device, wherein a liquid crystal of a driving cell and a liquid crystal of a compensation cell are formed of different liquid crystal materials to obtain a high contrast with respect to a temperature change.
Ｎ方式の液晶表示装置において、 補償セルの液晶は、駆動セルの液晶に対して、室温付近
では同じ複屈折率を持ち、室温より温度上昇するにした
がい複屈折率が低下する液晶材料で形成し、 温度変化に対して高いコントラストを得る構成としたこ
とを特徴とする液晶表示装置。2. A D-ST having a driving cell and a compensation cell.
In an N-type liquid crystal display device, the liquid crystal of the compensation cell is formed of a liquid crystal material having the same birefringence near room temperature as the liquid crystal of the drive cell, and having a lower birefringence as the temperature rises from room temperature. A liquid crystal display device characterized in that a high contrast is obtained with respect to a temperature change.
Ｎ方式の液晶表示装置において、 補償セルの液晶は、駆動セルの液晶に対して、室温付近
では同じ複屈折率を持ち、ネマティック相から等方相へ
の相転移温度が低い液晶材料で形成し、 温度変化に対して高いコントラストを得る構成としたこ
とを特徴とする液晶表示装置。3. A D-ST having a driving cell and a compensation cell.
In an N-type liquid crystal display device, the liquid crystal of the compensation cell is formed of a liquid crystal material having the same birefringence near room temperature as the liquid crystal of the driving cell and having a low phase transition temperature from a nematic phase to an isotropic phase. A liquid crystal display device characterized in that a high contrast is obtained with respect to a temperature change.
Priority Applications (1)
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|---|---|---|---|
| JP2000223535A JP4725871B2 (en) | 2000-07-25 | 2000-07-25 | Liquid crystal display |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000223535A JP4725871B2 (en) | 2000-07-25 | 2000-07-25 | Liquid crystal display |
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| Publication Number | Publication Date |
|---|---|
| JP2002040426A true JP2002040426A (en) | 2002-02-06 |
| JP4725871B2 JP4725871B2 (en) | 2011-07-13 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000223535A Expired - Fee Related JP4725871B2 (en) | 2000-07-25 | 2000-07-25 | Liquid crystal display |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004029700A1 (en) * | 2002-09-26 | 2004-04-08 | Sharp Kabushiki Kaisha | Patterning phase difference plate, production method for patterning phase difference plate, 2d/3d switching type liquid crystal display panel, and 2d/3d switching type liquid crystal display unit |
| CN102778785A (en) * | 2012-08-29 | 2012-11-14 | 信利半导体有限公司 | Passive driving nematic liquid crystal display panel |
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| JPH03111823A (en) * | 1989-09-27 | 1991-05-13 | Casio Comput Co Ltd | Two-layer type stn liquid crystal display element |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2004029700A1 (en) * | 2002-09-26 | 2004-04-08 | Sharp Kabushiki Kaisha | Patterning phase difference plate, production method for patterning phase difference plate, 2d/3d switching type liquid crystal display panel, and 2d/3d switching type liquid crystal display unit |
| US7557871B2 (en) | 2002-09-26 | 2009-07-07 | Sharp Kabushiki Kaisha | Patterning phase difference plate, production method for patterning phase difference plate, 2D/3D switching type liquid crystal display panel, and 2D/3D switching type liquid crystal display unit |
| US7773179B2 (en) | 2002-09-26 | 2010-08-10 | Sharp Kabushiki Kaisha | Patterning phase difference plate, production method for patterning phase difference plate, 2D/3D switching type liquid crystal display panel, and 2D/3D switching type liquid crystal display unit |
| CN102778785A (en) * | 2012-08-29 | 2012-11-14 | 信利半导体有限公司 | Passive driving nematic liquid crystal display panel |
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|---|---|
| JP4725871B2 (en) | 2011-07-13 |
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