JPH0346622A - liquid crystal electro-optical element - Google Patents

Abstract

PURPOSE:To obtain the liquid crystal electrooptical element having the high response speed applicable to a TV display of moving pictures, etc., by specifying the angle formed by the molecule major axis of a nematic liquid crystal with a substrate surface in the absence of applied electric fields to 30 to 65 deg.. CONSTITUTION:The liquid crystal electrooptical element constituted by crimping the nematic liquid crystal between transparent electrodes 103 provided on substrates 102 facing each other has 30 to 65 deg. angle (pretilt angle) 107 formed by the major axis of the nematic liquid crystal molecule 105 with the substrate surface in the absence of applied electric fields. Further, the arrangement of the liquid crystal molecules 105 in such liquid crystal layer has no spiral structure and the direction of the major axis of the liquid crystal molecules at the time of the non-impression of the electric fields has preferably the orientation structure in which the molecules 105 near two sheets of the substrates 102 parallel or nearly parallel with each other. The liquid crystal electrooptical element having the performance superior to the performance of the conventional TN system in terms of response and display performance is obtd. in this way.

Description

Translated fromJapanese

【発明の詳細な説明】［産業上の利用分野コ本発明は、デイスプレィ、ライトバルブ、光変調器など
の液晶電気光学素子装置に関し、さらに詳しくは液晶電
気光学素子の液晶分子の配向に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to liquid crystal electro-optical device devices such as displays, light valves, and optical modulators, and more particularly relates to the alignment of liquid crystal molecules in liquid crystal electro-optic devices.

［従来の技術］従来の液晶電気光学素子においては、液晶分子の長軸と
基板表面のなす角（プレチルト角）が１〜２０°で、か
つ上下の基板間で液晶分子の向きが９０〜２７０度程度
ねじられた構造を有するＴＮ型あるいはＳＴＮ型方式が
主流である。[Prior art] In conventional liquid crystal electro-optical elements, the angle between the long axis of the liquid crystal molecules and the substrate surface (pretilt angle) is 1 to 20 degrees, and the orientation of the liquid crystal molecules between the upper and lower substrates is 90 to 270 degrees. The mainstream is the TN type or STN type, which has a somewhat twisted structure.

［発明が解決しようとする課題及び目的コ従来の液晶電
気光学素子は、ねじれ構造によって透過光あるいは反射
光の制御を行なっているため、応答速度が劣る傾向にあ
り、動画のテレビ表示などには不適当な場合があった。[Problems and Objectives of the Invention] Conventional liquid crystal electro-optical elements use a twisted structure to control transmitted light or reflected light, so their response speed tends to be poor, making them unsuitable for displaying moving images on TV, etc. There were instances where it was inappropriate.

そこで、本発明は動画のＴＶ表示などにも応用が可能な
早い応答速度を有する液晶電気光学素子の開発を目的と
した。Therefore, the present invention aims to develop a liquid crystal electro-optical element having a fast response speed that can be applied to TV display of moving images.

［課題を解決するための手段］本発明者は前記問題点を解決するために鋭意努力した結
果、次の方法によれば応答速度の改善が可能であること
を見いだし、本発明に到った。[Means for Solving the Problems] As a result of diligent efforts to solve the above-mentioned problems, the inventor found that the response speed could be improved by the following method, and arrived at the present invention. .

すなわち、本発明の電気光学素子は、対向する２枚の基
板上に透明電極を設け、透明電極間にネマチイック液晶
を挟持してなる液晶電気光学素子において、電界無印加
時に該ネマチック液晶分子長軸が基板面に対してなす角
度（プレチルト角）が３０〜６５度であることを特徴と
する。That is, in the electro-optical element of the present invention, in a liquid crystal electro-optical element in which transparent electrodes are provided on two opposing substrates and a nematic liquid crystal is sandwiched between the transparent electrodes, the long axis of the nematic liquid crystal molecules when no electric field is applied. It is characterized in that the angle (pretilt angle) formed with respect to the substrate surface is 30 to 65 degrees.

さらに、かかる液晶層における液晶分子の配列がねじれ
構造を有せず、電界無印加時における液晶分子長軸の方
向が、２枚の各々の基板付近の分子同士が平行あるいは
ほぼ平行となる配向構造を有することが好ましい。Furthermore, the arrangement of liquid crystal molecules in such a liquid crystal layer does not have a twisted structure, and the direction of the long axis of the liquid crystal molecules when no electric field is applied is an alignment structure in which the molecules near each of the two substrates are parallel or almost parallel to each other. It is preferable to have.

本発明の液晶電気光学素子に、光学異方性を有する複屈
折体く光学補償板）を、該液晶層といずれか一方の偏光
板との間に、画面全体かあるいは部分的に配置して、視
覚範囲を広げることも可能である。In the liquid crystal electro-optical element of the present invention, a birefringent material (optical compensator) having optical anisotropy is disposed between the liquid crystal layer and one of the polarizing plates on the entire screen or partially. , it is also possible to widen the visual range.

［実施例］以下、実施例により本発明をより詳細に説明する。[Example]Hereinafter, the present invention will be explained in more detail with reference to Examples.

本発明で用いた液晶電気光学素子の構成を第１図に示す
。ここで、１０１は偏光板、１０２はガラス基板、ｌ○
３は透明電極、１０４は液晶を封じ込め、かつセル厚を
所定の値に設定するためのシール部である。封入した液
晶の正常光に対する屈折率、ｎｏ、は１．４９５、異常
光に対する屈折率、ｎｅ、は１．６０５であった。また
、１０５は液晶分子の配列を模式的に表わすもので、上
基板と下基板とで液晶分子長軸が平行あるいはほぼ平行
となるように配向処理されている。配向処理は、１０３
の透明電極上を薄くポリイミド樹脂とチタンカップリン
グ剤との混合物で覆い、その後布で一定方向にラビング
することにより行なった。このときのプレチルト角は４
８°　セル厚は５μｍであった。　　ラビングのこする
方向を上下基板で逆方向にこすることにより、上下基板
に接する液晶分子の長軸方向が平行あるいはほぼ平行の
配向を得た。FIG. 1 shows the structure of the liquid crystal electro-optical element used in the present invention. Here, 101 is a polarizing plate, 102 is a glass substrate, l○
3 is a transparent electrode, and 104 is a sealing portion for sealing the liquid crystal and setting the cell thickness to a predetermined value. The refractive index, no, of the sealed liquid crystal for normal light was 1.495, and the refractive index, ne, for extraordinary light was 1.605. Reference numeral 105 schematically represents the alignment of liquid crystal molecules, which are aligned so that the long axes of the liquid crystal molecules are parallel or nearly parallel between the upper and lower substrates. Orientation treatment is 103
The transparent electrode was covered with a thin layer of a mixture of a polyimide resin and a titanium coupling agent, and then rubbed in a certain direction with a cloth. The pretilt angle at this time is 4
The 8° cell thickness was 5 μm. By rubbing the upper and lower substrates in opposite directions, alignment was obtained in which the long axes of the liquid crystal molecules in contact with the upper and lower substrates were parallel or nearly parallel.

第２図は、本発明において用いた構成要素部分の光学的
な配置を現わし、２０１，２０２は上側ないし下側偏光
板の偏光軸で、各々直交するかほぼ直交した配置を有し
、さらに２０３は液晶分子の長軸方向を基板面へ投影し
た状態を現わし２０１と２０２の偏光軸に対しほぼ４５
°の配置を有する。FIG. 2 shows the optical arrangement of the component parts used in the present invention, and 201 and 202 are the polarization axes of the upper and lower polarizing plates, which are orthogonal to each other or substantially orthogonal to each other; 203 represents the state in which the long axis direction of the liquid crystal molecules is projected onto the substrate surface, and is approximately 45 degrees with respect to the polarization axes of 201 and 202.
It has an arrangement of °.

このようにして得た液晶表示セルの対向する透明電極間
に１００Ｈｚの短形波をＯＶから６■まで印加したとき
の透過率の変化を第３図の曲線３０１に示す。ＴＮ型（
ノーマリ−ホワイト）の場合の特性を３０２に示すが、
電界印加時、黒レベルの光漏れがみられる。Curve 301 in FIG. 3 shows the change in transmittance when a rectangular wave of 100 Hz was applied from OV to 6 cm between the opposing transparent electrodes of the liquid crystal display cell thus obtained. TN type (
The characteristics in the case of (normally white) are shown in 302,
When an electric field is applied, light leakage at black level is observed.

これは、ＴＮ型が第４図に示すような透過率の波長依存
性を示すためである。４０２，４０４はそれぞれ本発明
とＴＮ型の電界印加時（黒レベル）の波長特性を表わし
、４０１，４０３はそれぞれ本発明とＴＮ型における電
界無印加時（白レベル）における波長特性を表わす。こ
の図より明らかなように、ＴＮ型の黒レベルでは波長に
より光漏れを起こしているのに対し、本発明の液晶電気
光学素子では全波長にわたり均一な遮光がなされ黒がよ
り黒くなる結果が得られた。This is because the TN type exhibits wavelength dependence of transmittance as shown in FIG. 402 and 404 represent the wavelength characteristics of the present invention and the TN type, respectively, when an electric field is applied (black level), and 401 and 403 represent the wavelength characteristics of the present invention and the TN type, respectively, when no electric field is applied (white level). As is clear from this figure, while the TN type black level causes light leakage depending on the wavelength, the liquid crystal electro-optical element of the present invention blocks light uniformly over all wavelengths, resulting in darker blacks. It was done.

応答速度は、室温６Ｖ駆動で立ち」−かり、立ち下がり
ともに１５〜１７ｍ５ｅｃであり、同一条件におけるＴ
Ｎ型に比較して非常に速い速度が得られた。The response speed is 15 to 17 m5ec for both rise and fall when driven at 6V at room temperature, and T
A much faster speed was obtained compared to the N type.

［発明の効果］以上のように本発明の液晶電気光学素子を用いれば、応
答並びに表示性能の点で従来のＴＮ型方式を上回る性能
を有する液晶電気光学素子を得ることができる。[Effects of the Invention] As described above, by using the liquid crystal electro-optical element of the present invention, it is possible to obtain a liquid crystal electro-optical element that has performance superior to that of the conventional TN type system in terms of response and display performance.

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

第１図は本発明における液晶電気光学素子の構成を示す
図である。第２図は本発明における液晶電気光学素子の光学要素の
配置を示す図である。第３図は、本発明及び従来のＴＮ方式の電圧透過率特性
を示す図である。第４図は、本発明の実施例における透過率の波長特性を
、従来のＴＮ方式と比較して示した図である。１０１１０２０３０４１　０　５　−−−−−−１　０７　−−−−−−２０１、　２０２２０３　−−−−−３０１．３０２４０１、　４０２４０３、　４０４−　偏光板−ガラス基板一透明電極シール部液晶分子プレチルト角−偏光軸−液晶分子の長軸方向−本発明の液晶電気光学素子と従来のＴＮ型素子における電圧−透過率曲線一　本発明の液晶電気光学素子における透過率波長依存性〜　従来のＴＮ型素子における透過率波長特性以上FIG. 1 is a diagram showing the configuration of a liquid crystal electro-optical element according to the present invention. FIG. 2 is a diagram showing the arrangement of optical elements of the liquid crystal electro-optical element according to the present invention. FIG. 3 is a diagram showing the voltage transmittance characteristics of the present invention and the conventional TN system. FIG. 4 is a diagram showing wavelength characteristics of transmittance in an embodiment of the present invention in comparison with a conventional TN system. 101 102 03 04 1 0 5 ------- 1 07 ------- 201, 202 203 ------- 301.302 401, 402 403, 404 - Polarizing plate - glass substrate - transparent electrode sealing part Liquid crystal molecule pretilt angle - Polarization axis - Long axis direction of liquid crystal molecule - Voltage-transmittance curve in the liquid crystal electro-optical element of the present invention and a conventional TN type element Transmittance wavelength dependence in the liquid crystal electro-optical element of the present invention ~ Conventional Transmittance wavelength characteristics of TN type element or higher

Claims (1)

Translated fromJapanese

【特許請求の範囲】[Claims]対向する２枚の基板上に透明電極を設け、その透明電極
間にネマティック液晶を挟持してなる液晶電気光学素子
において、電界無印加時に該ネマチック液晶の分子長軸
が基板面に対してなす角度が３０〜６５度であることを
特徴とする液晶電気光学素子。In a liquid crystal electro-optical element in which transparent electrodes are provided on two opposing substrates and a nematic liquid crystal is sandwiched between the transparent electrodes, the angle that the molecular long axis of the nematic liquid crystal makes with the substrate surface when no electric field is applied. A liquid crystal electro-optical element characterized in that the angle is 30 to 65 degrees.