JPS6246845B2 - - Google Patents
Info
- Publication number
- JPS6246845B2 JPS6246845B2 JP58138710A JP13871083A JPS6246845B2 JP S6246845 B2 JPS6246845 B2 JP S6246845B2 JP 58138710 A JP58138710 A JP 58138710A JP 13871083 A JP13871083 A JP 13871083A JP S6246845 B2 JPS6246845 B2 JP S6246845B2
- Authority
- JP
- Japan
- Prior art keywords
- liquid crystal
- signal
- voltage
- electrode
- scanning
- 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.)
- Expired
Links
- 239000004973 liquid crystal related substance Substances 0.000 claims description 75
- 239000005262 ferroelectric liquid crystals (FLCs) Substances 0.000 claims description 14
- 238000000034 method Methods 0.000 description 32
- 230000005684 electric field Effects 0.000 description 26
- 230000003287 optical effect Effects 0.000 description 20
- 238000010586 diagram Methods 0.000 description 9
- 239000011159 matrix material Substances 0.000 description 8
- 239000000463 material Substances 0.000 description 7
- 210000004027 cell Anatomy 0.000 description 5
- 210000002858 crystal cell Anatomy 0.000 description 5
- 230000007423 decrease Effects 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 4
- 239000004988 Nematic liquid crystal Substances 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 230000005621 ferroelectricity Effects 0.000 description 2
- 238000012935 Averaging Methods 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 239000004990 Smectic liquid crystal Substances 0.000 description 1
- 229910006404 SnO 2 Inorganic materials 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 125000000484 butyl group Chemical group [H]C([*])([H])C([H])([H])C([H])([H])C([H])([H])[H] 0.000 description 1
- 229940114081 cinnamate Drugs 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- AMGQUBHHOARCQH-UHFFFAOYSA-N indium;oxotin Chemical compound [In].[Sn]=O AMGQUBHHOARCQH-UHFFFAOYSA-N 0.000 description 1
- 239000002052 molecular layer Substances 0.000 description 1
- 229920003987 resole Polymers 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 239000012780 transparent material Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/13306—Circuit arrangements or driving methods for the control of single liquid crystal cells
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3622—Control of matrices with row and column drivers using a passive matrix
- G09G3/3629—Control of matrices with row and column drivers using a passive matrix using liquid crystals having memory effects, e.g. ferroelectric liquid crystals
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/02—Addressing, scanning or driving the display screen or processing steps related thereto
- G09G2310/0202—Addressing of scan or signal lines
- G09G2310/0205—Simultaneous scanning of several lines in flat panels
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/04—Partial updating of the display screen
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/06—Details of flat display driving waveforms
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2310/00—Command of the display device
- G09G2310/06—Details of flat display driving waveforms
- G09G2310/065—Waveforms comprising zero voltage phase or pause
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0209—Crosstalk reduction, i.e. to reduce direct or indirect influences of signals directed to a certain pixel of the displayed image on other pixels of said image, inclusive of influences affecting pixels in different frames or fields or sub-images which constitute a same image, e.g. left and right images of a stereoscopic display
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/2007—Display of intermediate tones
- G09G3/2014—Display of intermediate tones by modulation of the duration of a single pulse during which the logic level remains constant
-
- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/2007—Display of intermediate tones
- G09G3/2018—Display of intermediate tones by time modulation using two or more time intervals
Landscapes
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Nonlinear Science (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Mathematical Physics (AREA)
- Optics & Photonics (AREA)
- Computer Hardware Design (AREA)
- Theoretical Computer Science (AREA)
- Liquid Crystal (AREA)
- Liquid Crystal Display Device Control (AREA)
Description
【発明の詳細な説明】
本発明は、液晶素子などの光学変調素子の駆動
法に係り、詳しくは表示素子やシヤツターアレイ
等の光学変調素子に用いる液晶素子の時分割駆動
法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for driving an optical modulation element such as a liquid crystal element, and more particularly to a time division driving method for a liquid crystal element used in an optical modulation element such as a display element or a shutter array.
従来より、走査電極群と信号電極群をマトリク
ス状に構成し、その電極間に液晶化合物を充填
し、多数の画素を形成して画像或いは情報の表示
を行う液晶表示素子は、よく知られている。この
表示素子の駆動法としては、走査電極群に、順
次、周期的にアドレス信号を選択印加し、信号電
極群には所定の情報信号をアドレス信号と同期さ
せて並列的に選択印加する時分割駆動が採用され
ているが、この表示素子及びその駆動法は、以下
に述べる如き致命的とも言える大きな欠点を有し
ていた。 Conventionally, liquid crystal display elements have been well known, which display images or information by configuring a scanning electrode group and a signal electrode group in a matrix, filling a liquid crystal compound between the electrodes, and forming a large number of pixels. There is. The driving method for this display element is a time-sharing method in which an address signal is selectively and periodically applied to a group of scanning electrodes, and a predetermined information signal is selectively applied in parallel to a group of signal electrodes in synchronization with the address signal. However, this display element and its driving method had major and fatal drawbacks as described below.
即ち、画素密度を高く、或いは画面を大きくす
るのが難しいことである。従来の液晶の中で応答
速度が比較的高く、しかも消費電力が小さいこと
から、表示素子として実用に供されているのは殆
んどが、例えば、M.SchadtとW.Helfrich著、
“Applied Physics Letters” Vol.18,No.4
(1971.2.15)、P.127〜128の”Voltage−
Dependent Optical Activity of a Twisted
Nematic Liquid Crystal”に示されたTN
(twisted nematic)型の液晶を用いたものであ
り、この型の液晶は、無電界状態で正の誘電異方
性をもつ、ネマチツク液晶の分子が、液晶層厚方
向で捩れた構造(ヘリカル構造)を形成し、両電
極面でこの液晶の分子が互いに並行に配列した構
造を形成している。一方、電界印加状態では、正
の誘電異方性をもつネマチツク液晶が電界方向に
配列し、この結果光学変調を起すことができる。
この型の液晶を用いてマトリクス電極構造によつ
て表示素子を構成した場合、走査電極と信号電極
が共に選択される領域(選択点)には、液晶分子
を電極面に垂直に配列させるに要する閾値以上の
電圧が印加され、走査電極と信号電極が共に選択
されない領域(非選択点)には電圧は印加され
ず、したがつて液晶分子は電極面に対して並行な
安定配列を保つている。このような液晶セルの上
下に、互いにクロスニコル関係にある直線偏光子
を配置することにより、選択点では光が透過せ
ず、非選択点では光が透過するため、画像素子と
することが可能となる。然し乍ら、マトリクス電
極構造を構成した場合には、走査電極が選択さ
れ、信号電極が選択されない領域或いは、走査電
極が選択されず、信号電極が選択される領域(所
調“半選択点”)にも有限の電界がかかつてしま
う。選択点にかかる電圧と、半選択点にかかる電
圧の差が充分に大きく、液晶分子を電界に垂直に
配列させるに要する電圧閾値がこの中間の電圧値
に設定されるならば、表示素子は正常に動作する
わけである。しかし、この方式において、走査線
数Nを増やして行つた場合、画面全体(1フレー
ム)を走査する間に一つの選択点に有効な電界が
かかつている時間(duty比)は、1/Nの割合
で減少してしまう。このために、くり返し走査を
行つた場合の選択点と非選択点かかる実効値とし
ての電圧差は、走査線数が増えれば増える程小さ
くなり、結果的には画像コントラストの低下やク
ロストークが避け難い欠点となつている。このよ
うな現像は、双安定性を有さない液晶(電極面に
対し、液晶分子が水平に配向しているのが安定状
態であり、電界が有効に印加されている間のみ垂
直に配向する)を、時間的蓄積効果を利用して駆
動する(即ち、繰り返し走査する)ときに生じる
本質的には避け難い問題点である。この点を改良
するために、電圧平均化法、2周波駆動法や多重
マトリクス法等が既に提案されているが、いずれ
の方法でも不充分であり、表示素子の大画面化や
高密度化は、走査線数が充分に増やせないことに
よつて頭打ちになつているのが現状である。本発
明の目的は、前述したような従来の液晶表示素子
における問題点を悉く解決した新規な光学変調素
子、特に液晶素子駆動法を提供することにある。 That is, it is difficult to increase the pixel density or enlarge the screen. Among conventional liquid crystals, most of them are used practically as display elements because of their relatively high response speed and low power consumption.
“Applied Letter Physics” Vol.18, No.4
(1971.2.15), P.127-128 “Voltage−
Dependent Optical Activity of a Twisted
TN shown in “Nematic Liquid Crystal”
This type of liquid crystal has a structure (helical structure) in which the molecules of the nematic liquid crystal, which have positive dielectric anisotropy in the absence of an electric field, are twisted in the thickness direction of the liquid crystal layer. ), and the liquid crystal molecules form a structure in which they are arranged parallel to each other on both electrode surfaces. On the other hand, when an electric field is applied, nematic liquid crystals with positive dielectric anisotropy are aligned in the direction of the electric field, resulting in optical modulation.
When a display element is constructed using this type of liquid crystal with a matrix electrode structure, in the region where both the scanning electrode and the signal electrode are selected (selected point), there is a A voltage higher than the threshold is applied, and no voltage is applied to areas where neither the scanning electrode nor the signal electrode is selected (non-selected points), so the liquid crystal molecules maintain a stable alignment parallel to the electrode surface. . By arranging linear polarizers above and below such a liquid crystal cell in a cross Nicol relationship, light does not pass through selected points, but light passes through non-selected points, making it possible to use it as an image element. becomes. However, when a matrix electrode structure is configured, there are areas where scanning electrodes are selected and signal electrodes are not selected, or areas where scanning electrodes are not selected and signal electrodes are selected (a "half-selected point"). The finite electric field is also strong. If the difference between the voltage applied to the selected point and the voltage applied to the half-selected point is sufficiently large, and the voltage threshold required to align liquid crystal molecules perpendicular to the electric field is set to a voltage value in between, the display element will function normally. This is why it works. However, in this method, when the number of scanning lines N is increased, the time during which an effective electric field is applied to one selected point while scanning the entire screen (one frame) (duty ratio) is 1/N. will decrease at the rate of For this reason, the effective voltage difference between selected points and non-selected points when repeated scanning is performed becomes smaller as the number of scanning lines increases, and as a result, a decrease in image contrast and crosstalk can be avoided. This has become a serious drawback. This type of development requires liquid crystals that do not have bistability (the stable state is when the liquid crystal molecules are aligned horizontally with respect to the electrode surface, and they are aligned vertically only while an electric field is effectively applied). ) is essentially an unavoidable problem that arises when driving using the temporal accumulation effect (that is, repeatedly scanning). In order to improve this point, voltage averaging method, dual frequency drive method, multiple matrix method, etc. have already been proposed, but all of these methods are insufficient, and it is difficult to increase the screen size and density of display elements. Currently, the number of scanning lines has reached a plateau due to the inability to increase the number of scanning lines sufficiently. An object of the present invention is to provide a novel optical modulation element, particularly a liquid crystal element driving method, which solves all the problems of conventional liquid crystal display elements as described above.
本発明の別の目的は、高速応答性を有する液晶
素子の駆動法を提供することにある。 Another object of the present invention is to provide a method for driving a liquid crystal element having high-speed response.
本発明の他の目的は、高密度の画素を有する液
晶素子の駆動法を提供することにある。 Another object of the present invention is to provide a method for driving a liquid crystal device having high density pixels.
さらに、本発明の他の目的は、クロストークを
発生しない液晶素子の駆動法を提供することにあ
る。 Furthermore, another object of the present invention is to provide a method for driving a liquid crystal element that does not generate crosstalk.
さらに、本発明の他の目的は、部分的な書き換
えが可能なデイスプレイ装置に適した液晶素子駆
動法を提供することにある。 Furthermore, another object of the present invention is to provide a method for driving a liquid crystal element suitable for a partially rewritable display device.
さらに、本発明の他の目的は、電界に対し双安
定性を有する液晶、特に強誘電性を有するカイラ
ルスメクテイツクC相又はH相の液晶を用いた液
晶素子の新規な駆動法を提供することにある。 Furthermore, another object of the present invention is to provide a novel method for driving a liquid crystal device using a liquid crystal that is bistable with respect to an electric field, particularly a chiral smect C-phase or H-phase liquid crystal that has ferroelectricity. There is a particular thing.
さらに、本発明の他の目的は、高密度の画素と
大面積の画面を有する液晶素子に適した新規な駆
動法を提供することにある。 Furthermore, another object of the present invention is to provide a novel driving method suitable for a liquid crystal device having a high density of pixels and a large screen area.
さらに本発明の特定の目的は、強誘電性液晶を
使用する表示素子のマトリクス電極による安定な
駆動法を提供することにある。 Furthermore, a specific object of the present invention is to provide a stable driving method using a matrix electrode of a display element using ferroelectric liquid crystal.
本発明の光学変調素子の駆動法は、上述の目的
を達成するために開発されたものであり、より詳
しくは、走査電極群と信号電極群とを有し、該走
査電極群と信号電極群との間に、電界に対して双
安定性を有する光学変調物質を配置した構造を有
する光学変調素子の駆動法において、前記走査電
極群の選択された走査電極と前記信号電極群の選
択された信号電極との間で、前記双安定性を有す
る光学変調物質が第1の安定状態に配向する電
圧、VON1を印加し、且つ前記選択された走査電
極と前記信号電極群の選択されない信号電極との
間で、前記双安定性を有する光学変調物質が第2
の安定状態に配向する電圧VON2を印加するとと
もに、前記走査電極群の選択されない走査電極と
前記信号電極群との間で、前記双安定性を有する
光学変調物質の閾値電圧−Vth2(第2安定状態
の閾値電圧を言う)とVth1(第1安定状態の閾
値電圧を言う)との間の値に設定した電圧VOFF
を印加しし、各々の電圧VON1,VON2,VOFFに
以下の関係
2|VOFF|<VON1|,|VON2|
を満足させることを特徴とするものである。 The method for driving an optical modulation element of the present invention was developed to achieve the above-mentioned object, and more specifically includes a scanning electrode group and a signal electrode group, the scanning electrode group and the signal electrode group In a method for driving an optical modulation element having a structure in which an optical modulation material having bistable property with respect to an electric field is arranged between a selected scanning electrode of the scanning electrode group and a selected scanning electrode of the signal electrode group, A voltage V ON1 that orients the bistable optical modulating material to a first stable state is applied between the signal electrode and the selected scanning electrode and the unselected signal electrode of the signal electrode group. and the bistable optical modulating material is in a second state.
At the same time, a voltage V ON2 is applied to align the optical modulation substance in a stable state, and a threshold voltage −Vth 2 (Vth 2 The voltage V OFF is set to a value between Vth 1 (which refers to the threshold voltage in the 2nd stable state) and Vth 1 (which refers to the threshold voltage in the 1st stable state).
is applied, and each of the voltages V ON1 , V ON2 , and V OFF satisfies the following relationship: 2|V OFF |<V ON1 |, |V ON2 |.
本発明の好ましい具体例では、走査信号に基づ
いて順次選択される走査電極群と、該走査電極群
に対向し所定の情報信号に基づいて選択される信
号電極群と、の間に電界に対して双安定性を有す
る液晶を挾持させてなる液晶素子の、選択された
走査電極には位相t1とt2において互いに電圧極性
が異なる電気信号V1(t){その位相t1およびt2
を含む位相間隔内での、最大値をV1(t)nax、最
小値をV1(t)nioとする}を与え、且つ信号電極
群には所定の情報の有、無に応じて、電圧の異な
る電気信号V2およびV2′を与える。すなわち、上
記選択された走査電極線上の情報信号有の部分に
おいては、位相t1(またはt2)で上記液晶に対して
第1の安定状態を与える一方向の電界V2−V1
(t)を付与し、無の部分に於ては、位相t2(ま
たはt1)で第2の安定状態を与える逆方向の電界
V2′―V1(t)を付与し且つ以下の関係を満足さ
せることによつて、特に安定に液晶素子を駆動す
ることができる。 In a preferred embodiment of the present invention, an electric field is formed between a scanning electrode group that is sequentially selected based on a scanning signal and a signal electrode group that faces the scanning electrode group and is selected based on a predetermined information signal. A selected scanning electrode of a liquid crystal element in which a bistable liquid crystal is sandwiched between the electrodes is supplied with an electric signal V 1 (t) having different voltage polarity at phases t 1 and t 2 {the phases t 1 and t 2
The maximum value is V 1 (t) nax and the minimum value is V 1 (t) nio within a phase interval including Give electrical signals V 2 and V 2 ′ of different voltages. That is, in the portion of the selected scanning electrode line where the information signal is present, a unidirectional electric field V 2 −V 1 which provides the first stable state to the liquid crystal at phase t 1 (or t 2 ) is generated.
(t), and in the empty part, an electric field in the opposite direction that gives a second stable state at phase t 2 (or t 1 )
By providing V 2 '−V 1 (t) and satisfying the following relationship, the liquid crystal element can be driven particularly stably.
1<|V1(t)nax|/|V2|
1<|V1(t)nio|/|V2|
1<|V1(t)nax|/|V2′|
および
1<|V1(t)nio|/|V2′|
その具体例の詳細は、図面を参照しつつ、後程
説明する。 1<|V 1 (t) nax |/|V 2 | 1<|V 1 (t) nio |/|V 2 | 1<|V 1 (t) nax |/|V 2 ′| and 1<| V 1 (t) nio |/|V 2 ′| Details of the specific example will be explained later with reference to the drawings.
本発明の駆動法で用いる光学変調物質として
は、加えられる電界に応じて第1の光学的安定状
態と第2の光学的安定状態とのいずれかを取る、
すなわち電界に対する双安定状態を有する物質、
特にこのような性質を有する液晶、が用いられ
る。 The optical modulation substance used in the driving method of the present invention takes either a first optically stable state or a second optically stable state depending on the applied electric field.
In other words, a substance that has a bistable state in response to an electric field,
In particular, liquid crystals having such properties are used.
本発明の駆動法で用いることができる双安定性
を有する液晶としては、強誘電性を有するカイラ
ルスメクテイツク液晶が最も好ましく、そのうち
カイラルスメクテイツクC相(SmC*)又はH
相(SmH*)の液晶が適している。この強誘電
性液晶については、“LE JOURNAL DE
PHYSIQUE LETTERS”36(L−69)1975),
「Ferroelectric Liquid Crystals」;“Applied
Physics Let−ters”36(11)1980,「Submicro
Second Bi−stable Electrooptic Switching in
Liquid Crystals」;“固体物理”16(141)1981
「液晶」等に記載されており、本発明ではこれら
に開示された強誘電性液晶を用いることができ
る。 As the liquid crystal having bistability that can be used in the driving method of the present invention, a chiral smectic liquid crystal having ferroelectricity is most preferable.
Phase (SmH * ) liquid crystal is suitable. For more information on this ferroelectric liquid crystal, please refer to “LE JOURNAL DE
PHYSIQUE LETTERS” 36 (L-69) 1975),
“Ferroelectric Liquid Crystals”; “Applied
Physics Letters” 36 (11) 1980, “Submicro
Second Bi−stable Electrooptic Switching in
Liquid Crystals”; “Solid State Physics” 16 (141) 1981
The ferroelectric liquid crystals disclosed in these documents can be used in the present invention.
より具体的には、本発明法に用いられる強誘電
性液晶化合物の例としては、デシロキシベンジリ
デン―p′―アミノ―2―メチルブチルシンナメー
ト(DOBAMBC)、ヘキシルオキシベンジリデン
―p′―アミノ―2―クロロプロピルシンナメート
(HOBACPC)および4―o―(2―メチル)―
ブチルレゾルシリデン―4′―オクチルアニリン
(MBRA8)等が挙げられる。 More specifically, examples of ferroelectric liquid crystal compounds used in the method of the present invention include decyloxybenzylidene-p'-amino-2-methylbutylcinnamate (DOBAMBC), hexyloxybenzylidene-p'-amino- 2-chloropropyl cinnamate (HOBACPC) and 4-o-(2-methyl)-
Examples include butyl resol cylidene-4'-octylaniline (MBRA8).
これらの材料を用いて、素子を構成する場合、
液晶化合物が、SmC*相又はSmH*相となるよ
うな温度状態に保持する為、必要に応じて素子を
ヒーターが埋め込まれた銅ブロツク等により支持
することができる。 When constructing an element using these materials,
In order to maintain the temperature state such that the liquid crystal compound becomes the SmC * phase or the SmH * phase, the element can be supported by a copper block or the like in which a heater is embedded, if necessary.
第1図は、強誘電性液晶セルの例を模式的に描
いたものである。21と21′は、In2O3、SnO2
やITO(Indium−Tin Oxide)等の透明電極がコ
ートされた基板(ガラス板)であり、その間に液
晶分子層22がガラス面に垂直になるよう配向し
たSmC*相の液晶が封入されている。太線で示
した線23が液晶分子を表わしており、この液晶
分子23は、その分子に直交した方向に双極子モ
ーメントP⊥24を有している。基板21と2
1′上の電極間に一定の閾値以上の電圧を印加す
ると、液晶分子23のらせん構造がほどけ、双極
子モーメントP⊥24はすべて電界方向に向くよ
う、液晶分子23の配向方向を変えることができ
る。液晶分子23は細長い形状を有しており、そ
の長軸方向と短軸方向で屈折率異方性を示し、従
つて例えばガラス面の上下に互いにクロスニコル
の位置関係に配置した偏光子を置けば、電圧印加
極性によつて光学特性が変わる液晶光学変調素子
となることは、容易に理解される。さらに液晶セ
ルの厚さを充分に薄くした場合(例えば1μ)に
は、第2図に示すように電界を印加していない状
態でも液晶分子のらせん構造は、ほどけ、その双
極子モーメントP又はP′は上向き34又は下向3
4′のどちらかの状態をとる。このようなセルに
第2図に示す如く一定の閾値以上の極性の異る電
界E又はE′を付与すると、双極子モーメント電
界E又はE′はの電界ベクトルに対応して上向き
34又は、下向き34′と向きを変え、それに応
じて液晶分子は第1の安定状態33かあるいは第
2の安定状態33′の何れか1方に配向する。 FIG. 1 schematically depicts an example of a ferroelectric liquid crystal cell. 21 and 21' are In 2 O 3 , SnO 2
It is a substrate (glass plate) coated with transparent electrodes such as ITO (Indium-Tin Oxide), etc., and SmC * phase liquid crystal with liquid crystal molecular layer 22 oriented perpendicular to the glass surface is sealed between them. . A thick line 23 represents a liquid crystal molecule, and this liquid crystal molecule 23 has a dipole moment P⊥24 in a direction perpendicular to the molecule. Boards 21 and 2
When a voltage higher than a certain threshold is applied between the electrodes 1', the helical structure of the liquid crystal molecules 23 is unraveled, and the orientation direction of the liquid crystal molecules 23 can be changed so that the dipole moment P⊥24 is all oriented in the direction of the electric field. can. The liquid crystal molecules 23 have an elongated shape and exhibit refractive index anisotropy in the long axis direction and the short axis direction. Therefore, for example, polarizers arranged in a crossed nicol position can be placed above and below the glass surface. For example, it is easily understood that the liquid crystal optical modulation element is a liquid crystal optical modulation element whose optical characteristics change depending on the polarity of applied voltage. Furthermore, when the thickness of the liquid crystal cell is made sufficiently thin (for example, 1μ), the helical structure of the liquid crystal molecules unravels even when no electric field is applied, and its dipole moment P or P ' is upward 34 or downward 3
4'. When an electric field E or E' with a different polarity above a certain threshold is applied to such a cell as shown in Fig. 2, the dipole moment electric field E or E' will move upward 34 or downward depending on the electric field vector. 34', and accordingly the liquid crystal molecules are oriented either in the first stable state 33 or in the second stable state 33'.
このような強誘電性液晶を光学変調素子として
用いることの利点は2つある。第1に、応答速度
が極めて速いこと、第2の液晶分子の配向が双安
定性を有することである。第2の点を、例えば第
2図によつて説明すると、電界Eを印加すると液
晶分子は第1の安定状態33に配向するが、この
状態は電界を切つても安定である。又、逆向きの
電界E′を印加すると、液晶分子は第2の安定状
態33′に配向して、その分子の向きを変える
が、やはり電界を切つてもこの状態に留つてい
る。又、与える電界Eが一定の閾値を越えない限
り、それぞれの配向状態にやはり維持されてい
る。このような応答速度の速さと、双安定性が有
効に実現されるには、セルとしては出来るだけ薄
い方が好ましく、一般的には、0.5μ〜20μ、特
に1μ〜5μが適している。この種の強誘電性液
晶を用いたマトリクス電極構造を有する液晶―電
気光学装置は、例えばクラークとラガバルによ
り、米国特許第4367924号明細書で提案されてい
る。 There are two advantages to using such a ferroelectric liquid crystal as an optical modulation element. First, the response speed is extremely fast, and the second liquid crystal molecule orientation has bistability. The second point will be explained with reference to FIG. 2, for example. When the electric field E is applied, the liquid crystal molecules are oriented in a first stable state 33, and this state remains stable even when the electric field is turned off. When an electric field E' in the opposite direction is applied, the liquid crystal molecules are oriented to a second stable state 33' and change their orientation, but they remain in this state even after the electric field is turned off. Further, as long as the applied electric field E does not exceed a certain threshold value, each orientation state is maintained. In order to effectively realize such a fast response speed and bistability, it is preferable that the cell be as thin as possible, and generally 0.5 μ to 20 μ, particularly 1 μ to 5 μ is suitable. A liquid crystal-electro-optical device having a matrix electrode structure using a ferroelectric liquid crystal of this kind has been proposed by Clark and Ragaval in US Pat. No. 4,367,924, for example.
本発明の駆動法の好ましい具体例を、第3図A
―Bを用いて説明する。 A preferred specific example of the driving method of the present invention is shown in FIG.
-Explain using B.
第3図A―aは、中間に強誘電性液晶化合物
(図示せず)が挟まれたマトリクス電極構造を有
するセル11の電極の模式配置図である。12は
走査電極群であり、13は信号電極群である。第
3図A―bとA―cはそれぞれ選択された走査電
極12sに与えられる電気信号とそれ以外の走査
電極(選択されない走査電極)12nに与えられ
る電気信号を示し、第3図A―dとA―eはそれ
ぞれ選択された信号電極13sに与えられる電気
信号と選択されない信号電極13nに与えられる
電気信号を表わす。第3図A―b〜A―eにおい
ては、それぞれ横軸が時間を、縦軸が電圧を表
す。例えば、動画を表示するような場合には、走
査電極群12は逐次、周期的に選択される。今、
双安定性を有する液晶セルの、第1の安定状態を
与えるための閾値電圧をVth1とし、第2の安定
状態を与えるための閾値電圧を−Vth2とする
と、選択された走査電極12sに与えられる電極
信号は、第3図A―bに示される如く位相(時
間)t1では、V1を、位相(時間)t2では、−V1と
なるような交番する電圧である。このように選択
された走査電極に互いに電圧の異なる複数の位相
間隔を有する電気信号を印加すると、光学的
「明」あるいは「暗」状態に相当する液晶の第1
あるいは第2の安定状態間での状態変化を、速や
かに起させるこてができるという重要な効果が得
られる。 FIG. 3A-a is a schematic layout diagram of the electrodes of a cell 11 having a matrix electrode structure in which a ferroelectric liquid crystal compound (not shown) is sandwiched between. 12 is a scanning electrode group, and 13 is a signal electrode group. 3A-b and A-c respectively show the electric signal given to the selected scan electrode 12s and the electric signal given to the other scan electrodes (unselected scan electrodes) 12n, and FIG. 3A-d and Ae represent the electric signal applied to the selected signal electrode 13s and the electric signal applied to the unselected signal electrode 13n, respectively. In FIGS. 3A-b to 3-e, the horizontal axis represents time and the vertical axis represents voltage. For example, when displaying a moving image, the scanning electrode groups 12 are sequentially and periodically selected. now,
Assuming that the threshold voltage for providing the first stable state of a liquid crystal cell having bistable property is Vth 1 , and the threshold voltage for providing the second stable state is -Vth 2 , the voltage applied to the selected scan electrode 12s is The applied electrode signal is an alternating voltage that is V 1 at phase (time) t 1 and -V 1 at phase (time) t 2 as shown in FIG. 3A-B. When electrical signals having a plurality of phase intervals with mutually different voltages are applied to the scanning electrodes selected in this way, the first phase of the liquid crystal corresponds to the optical "bright" or "dark" state.
Alternatively, an important effect can be obtained in that a state change between the second stable states can be quickly caused.
一方、それ以外の走査電極12nは、第3図A
―cに示す如くアース状態となつており、電気信
号0である。また、選択された信号電極13sに
与えられる電気信号は、第3図A―dに示される
如くV2であり、また選択されない信号電極13
nに与えられる電気信号は、第3図A―eに示さ
れる如く−V2である。以上に於て各々の電圧値
は、以下の関係を満足する所望の値に設定され
る。 On the other hand, the other scanning electrodes 12n are as shown in FIG.
- As shown in c, it is in a grounded state and the electrical signal is 0. Further, the electric signal applied to the selected signal electrode 13s is V2 as shown in FIG. 3A-d, and the electric signal applied to the unselected signal electrode 13s is
The electrical signal applied to n is -V 2 as shown in FIG. 3A-e. In the above, each voltage value is set to a desired value that satisfies the following relationship.
V2,(V1―V2)<Vth1<V1+V2および―(V1+
V2)<−Vth2<―V2,―(V1―V2)。V 2 , (V 1 − V 2 ) < Vth 1 < V 1 + V 2 and − (V 1 +
V 2 )<−Vth 2 <−V 2 ,−(V 1 −V 2 ).
このような電気信号が与えられたときの各画
素、すなわち第3図A―aに示される画素A,
B,CおよびD、にそれぞれ印加される電圧波形
を、第3図Bのa,b,cおよびdに示す。すな
わち、第3図B―a〜dより明らかな如く、選択
された走査線上にある画素Aでは、位相t2に於
て、閾値Vth1を越える電圧V1+V2が印加され
る。又、同一走査線上に存在する画素Bでは位相
t1に於て閾値−Vth2を越える電圧―(V1+V2)が
印加される。従つて、選択された走査電極線上に
於て、信号電極が選択されたか否かに応じて、選
択された場合には、液晶分子は第1の安定状態に
配向を揃え、選択されない場合には第2の安定状
態に配向を揃える。いずれにしても各画素の前歴
には関係することはない。 Each pixel when such an electric signal is applied, that is, pixel A shown in FIG.
The voltage waveforms applied to B, C, and D, respectively, are shown in a, b, c, and d of FIG. 3B. That is, as is clear from FIGS. 3B-a to 3-d, a voltage V 1 +V 2 exceeding the threshold value Vth 1 is applied to the pixel A on the selected scanning line at phase t 2 . Also, in pixel B existing on the same scanning line, the phase
At t 1 , a voltage exceeding the threshold value −Vth 2 −(V 1 +V 2 ) is applied. Therefore, depending on whether a signal electrode is selected on the selected scanning electrode line, if the signal electrode is selected, the liquid crystal molecules are aligned in the first stable state, and if not selected, the liquid crystal molecules are aligned in the first stable state. Align the orientation to a second stable state. In any case, it has nothing to do with the previous history of each pixel.
一方、画素CとDに印加される電圧は、第3図
B,cおよびdに示される如く、選択されない走
査線上では、すべての画素CとDに印加される電
圧はV2又は、−V2であつて、いずれも閾値電圧を
越えない。従つて、各画素CとDにおける液晶分
子は、配向状態を変えることなく前回走査された
ときの信号状態に対応した配向を、そのまま保持
している。即ち、走査電極が選択されたときにそ
の1ライン分の信号の書き込みが行われ、1フレ
ームが終了して次回選択されるまでの間は、その
信号状態を保持し得るわけである。従つて、走査
電極数が増えても、実質的なデユーテイ比はかわ
らず、コトラストの低下は全く生じない。この際
に、V1及びV2の値、ならびに位相(t1+t2)=T
の値としては、用いられる液晶材料やセルの厚さ
にも依存すが、通常3ボルト〜70ボルトで、0.1
μsec〜2msecの範囲が用いられる。ここで、本
発明の方法では、選択された走査電極に与えられ
る電気信号が、第1の安定状態(光信号に変換さ
れたとき「明」状態であるとする」から第2の安
定状態(光信号に変換されたとき「暗」状態であ
るとする)へ、又はその逆へのいずれの変化をも
起し易くするために、選択された走査電極には、
例えば+V1から−V1へと、交番する電圧信号を
与えることを重要な特徴とする。又、信号電極に
与えられる電圧は、明又は暗の状態を指定すべ
く、互いに異なる電圧としている。 On the other hand, as shown in FIG. 3B, c and d, the voltages applied to all pixels C and D are V 2 or -V on unselected scan lines. 2 , and neither exceeds the threshold voltage. Therefore, the liquid crystal molecules in each pixel C and D maintain the orientation corresponding to the signal state when scanned last time without changing the orientation state. That is, when a scanning electrode is selected, a signal for one line is written, and that signal state can be maintained until the next selection after one frame is completed. Therefore, even if the number of scanning electrodes increases, the actual duty ratio remains unchanged and contrast does not decrease at all. At this time, the values of V 1 and V 2 and the phase (t 1 + t 2 ) = T
Although it depends on the liquid crystal material used and the thickness of the cell, the value of is usually 3 volts to 70 volts and 0.1
A range of μsec to 2 msec is used. Here, in the method of the present invention, the electrical signal applied to the selected scanning electrode is changed from a first stable state (assumed to be a "bright" state when converted into an optical signal) to a second stable state (assumed to be a "bright" state when converted into an optical signal). Selected scan electrodes include:
An important feature is that it provides an alternating voltage signal, for example from +V 1 to -V 1 . Further, the voltages applied to the signal electrodes are set to be different voltages to specify a bright or dark state.
さて上記においては、双安定性、強誘電性液晶
の動作ならびに駆動方法が、多分に理想的な状態
に基づいて説明されている。例えば、双安定性液
晶とはいつても、実際には、電界の無い状態で無
限に長い時間、一方の安定状態に留まるわけでは
ない。より具体的に例示すると、温度70℃におい
て、厚さ3μm程度以上の強誘電性液晶
DOBAMBCの層の場合、SmC*相において最初
は一部らせん構造が残つている。これに、層厚方
向に一方向の電界(例えば+30V/3μm)を印
加すると、らせん構造が完全にほどけて、液晶分
子は面内一様配向状態に転移する。この後に、無
電界状態に戻した場合、液晶分子は、徐々に一部
らせん構造に戻つていくため、液晶セルを上下一
対の直交ニコルで挟んで透過光を観測すると、
徐々に表示のコントラストが低下していく。この
一方向の安定状態が解除されていく速度は、液晶
材料を挟持する一対の基板の表面状態(表面材
質、表面処理等)及び液晶層厚に強く依存する。
また先の説明では、一方向の安定状態に転移させ
るに必要な閾値電圧Vth1およびVth2を一義的な
値として定義したが、この値も基板の表面状態等
の要因に強く依存するため個々のセルによるバラ
ツキが大きい。更に、閾値電圧は、電圧印加時間
にも依存し、電圧印加時間が長くなると、閾値電
圧は低下していく傾向にあるため、信号の形態に
よつては、非選択線上でも液晶の2つの安定状態
間で転移が生じ、クロストークを生じる危険性を
はらんでいる。 Now, in the above, the operation and driving methods of bistable, ferroelectric liquid crystals have been explained based on mostly ideal conditions. For example, a bistable liquid crystal does not actually remain in one stable state for an infinitely long time in the absence of an electric field. To give a more specific example, a ferroelectric liquid crystal with a thickness of about 3 μm or more at a temperature of 70°C
In the case of the DOBAMBC layer, some helical structure initially remains in the SmC * phase. When a unidirectional electric field (for example, +30 V/3 μm) is applied to this layer in the layer thickness direction, the helical structure is completely unwound and the liquid crystal molecules are transferred to a uniform in-plane alignment state. After this, when the state is returned to a no-electric field state, the liquid crystal molecules gradually return to a helical structure, so if the liquid crystal cell is sandwiched between a pair of upper and lower crossed Nicols and the transmitted light is observed,
The contrast of the display gradually decreases. The speed at which this unidirectional stable state is released strongly depends on the surface condition (surface material, surface treatment, etc.) of the pair of substrates sandwiching the liquid crystal material and the thickness of the liquid crystal layer.
In addition, in the previous explanation, the threshold voltages Vth 1 and Vth 2 necessary for transition to a stable state in one direction were defined as unique values, but these values also strongly depend on factors such as the surface condition of the substrate, so they cannot be determined individually. There are large variations depending on the cell. Furthermore, the threshold voltage also depends on the voltage application time, and as the voltage application time increases, the threshold voltage tends to decrease. There is a risk of transfer between states and crosstalk.
以上のことから、実際に光学変調素子を安定に
作成し、駆動させようとする場合には、選択点に
おいて第1および第2の安定状態に配向する電圧
VON1およびVON2ならびに非選択点に於て印加す
る電圧VOFFの値を、それぞれ、平均的な閾値電
圧Vth1およびVth2から、できるだけ離間して設
定するのが好ましい。そして素子間でのバラツ
キ、或いは素子内でのバラツキを考慮した場合、
|VOFF|の値に対して、|VON1|、および|V
ON2|の値が2倍以上であることが、安定性を得
る上で好ましいことが確認された。また、このよ
うな電圧印加条件を、二つの安定状態間での状態
変化を速やかに達成できる第3図で説明した駆動
方法において実現する場合には、選択された走査
電極と、選択されない信号電極とによつて、情報
無しに対応する画素に印加される電圧(第3図B
―b)の、位相t2における電圧値|V1−V2|の値
も、非選択画素に印加される電圧VOFFと同様
に、VON1の値から充分に離間して、特にVON1の
1/1.2以下に設定するのが好ましい。したがつ
て、第3図の例に対応して云えば
1<|V1(t)|/|V2|<10
がそのための条件になる。更に一般的に述べるな
らば、各画素への印加電圧ならびに各電極に与え
る電気信号は、対称的である必要も、階段状であ
る必要もない。このような場合も含めて一般的に
表わすために、位相t1+t2内での走査電極に加え
られる電気信号(アース電位との差による電圧)
の最大値をV1(t)nax、最小値をV1(t)nioと
し、また選択された信号電極に印加される情報有
に対応する電気信号をV2、選択されない信号電
極に印加される情報無に対応する電気信号(いず
れも、アース電位との差による電圧)をV2′とす
るとき、以下の条件が満足されることが安定な駆
動のために好ましい。 From the above, when trying to actually create and drive an optical modulation element stably, it is necessary to apply voltages V ON1 and V ON2 that are oriented to the first and second stable states at the selected point and to the non-selected points. It is preferable that the values of the applied voltages V OFF are set as far away from the average threshold voltages V th 1 and V th 2 as possible. When considering variations between elements or within elements,
For the value of |V OFF |, |V ON1 | and |V
It was confirmed that it is preferable for the value of ON2 | to be twice or more in order to obtain stability. In addition, when realizing such voltage application conditions using the driving method described in FIG. 3, which can quickly change the state between two stable states, it is necessary to According to the voltage applied to the corresponding pixel without information (Fig. 3B)
- b), the voltage value |V 1 −V 2 | at phase t 2 is also sufficiently spaced from the value of V ON1, similar to the voltage V OFF applied to the non-selected pixel, and especially V ON1 It is preferable to set it to 1/1.2 or less. Therefore, corresponding to the example of FIG. 3, the condition is 1<|V 1 (t)|/|V 2 |<10. More generally speaking, the voltage applied to each pixel and the electrical signal applied to each electrode need not be symmetrical or stepped. In order to express it generally, including this case, the electrical signal (voltage due to the difference from ground potential) applied to the scanning electrode within phase t 1 + t 2
Let V 1 (t) nax be the maximum value of V 1 (t) nax and let V 1 (t) nio be the minimum value of When the electric signal corresponding to the absence of information (both are voltages due to the difference from the ground potential) is V 2 ', it is preferable for stable driving that the following conditions be satisfied.
1<|V1(t)nax|/|V2|<10
1<|V1(t)nio|/|V2|<10
1<|V1(t)nax|/|V2′|<10
および
1<|V1(t)nio|/|V2′|<10
第3図で説明した実施例に基づいて、走査電極
に加えられる電気信号V1と信号電極に加えられ
る電気信号±V2の比率を変えた場合の、選択点
(選択信号電極と選択あるいは非選択走査電極と
の間)に印加される最大電圧|V1+V2|と、非
選択点(非選択信号電極と選択あるいは非選択走
査電極との間)に印加される電圧|V2|、およ
び選択点において、例えば第3図B―aの位相t1
(あるいは第3図B―bの位相t2)印加される電圧
|V2−V1|(いずれも絶対値で表示する)との
比率をグラフに表わしたのが第4図である。この
グラフより分るように、比k=|V1/V2|の値
は、1<k、特に1<k<10の範囲とすることが
好ましい。 1<|V 1 (t) nax |/|V 2 |<10 1<|V 1 (t) nio |/|V 2 |<10 1<|V 1 (t) nax |/|V 2 ′| <10 and 1<|V 1 (t) nio |/|V 2 '|<10 Based on the embodiment described in FIG. 3, the electrical signal V 1 applied to the scanning electrode and the electrical signal applied to the signal electrode When the ratio of ±V 2 is changed, the maximum voltage |V 1 +V 2 | applied to the selected point (between the selected signal electrode and the selected or unselected scanning electrode) and the unselected point (unselected signal electrode) and the selected or unselected scan electrode), and at the selected point, the phase t 1 of FIG. 3B -a, for example.
(or the phase t 2 in FIG. 3 B-b) and the applied voltage |V 2 −V 1 | (both are expressed as absolute values) are graphed in FIG. 4. As can be seen from this graph, the value of the ratio k=|V 1 /V 2 | is preferably in the range of 1<k, particularly 1<k<10.
本発明の駆動法が有効に達成されるためには、
走査電極或いは信号電極に与えられる電気信号が
必ずしも第3図A―b〜e及び第3図B−a〜d
に於て説明されたような、単純な矩形波信号でな
くてもよいことは自明である。例えば、有効な時
間巾が与えられる限りにおいて、正弦波や三角波
によつて駆動することも可能である。 In order to effectively achieve the driving method of the present invention,
The electrical signals given to the scanning electrodes or signal electrodes are not necessarily the same as those shown in FIGS.
It is obvious that the signal does not need to be a simple rectangular wave signal as explained in . For example, it is also possible to drive with a sine wave or a triangular wave, as long as an effective time span is provided.
第5図は、本発明の駆動法の好ましい適用対象
の一例としての、液晶―光シヤツターの模式平面
図である。ここで、41は画素であつて、この部
分のみ両側の電極を透明なもので形成している。
マトリクス電極は、走査電極群42と、信号電極
群43により構成されている。 FIG. 5 is a schematic plan view of a liquid crystal-light shutter as an example of a preferable application of the driving method of the present invention. Here, 41 is a pixel, and the electrodes on both sides of this portion are made of transparent material.
The matrix electrode is composed of a scanning electrode group 42 and a signal electrode group 43.
第1図は、カイラルスメクテイツク相液晶を有
する液晶素子を、模式的に示す斜視図である。第
2図は、本発明法で用いる液晶素子の双安定性を
模式的に示す斜視図である。第3図A,aは、本
発明の駆動法に用いる液晶素子の電極配列状態を
模式的に示す平面図である。第3図A,bは選択
された走査電極に加えられる電気信号波形図であ
る。第3図A,cは、選択されない走査電極に加
えられる信号波形図である。第3図A,dは、選
択された信号電極に加えられる情報信号波形図で
ある。第3図A,eは、選択されない信号電極に
加えられる情報信号波形図である。第3図B,a
は、画素Aの液晶に印加される電圧の波形図であ
る。第3図B,bは、画素Bの液晶に印加される
電圧の波形図である。第3図B,cは、画素cの
液晶に印加される電圧の波形図である。第3図
B,dは、画素Dの液晶に印加される電圧の波形
図である。第4図は、走査電極に加えられる電気
信号V1と信号電極に加えられる電気信号±V2の
比の絶対値kの変化による駆動安定性の変化を示
すグラフである。第5図は、本発明の駆動法の好
ましい適用対象の一例としての、液晶―光シヤツ
ターの模式平面図である。
11……液晶素子、12……走査電極群、12
a……選択された走査電極、12n……選択され
ない走査電極、13……信号電極群、13s……
選択された信号電極、13n……選択されない信
号電極、33……第1の安定状態に配向した液
晶、33′……第2の安定状態に配向した液晶、
34……上向き双極子モーメントP、34′……
下向き双極子モーメントP′、41……画素、42
……走査電極群、43……信号電極群。
FIG. 1 is a perspective view schematically showing a liquid crystal element having a chiral smectoid phase liquid crystal. FIG. 2 is a perspective view schematically showing the bistability of the liquid crystal element used in the method of the present invention. FIGS. 3A and 3A are plan views schematically showing the arrangement of electrodes of a liquid crystal element used in the driving method of the present invention. FIGS. 3A and 3B are electrical signal waveform diagrams applied to selected scanning electrodes. FIGS. 3A and 3C are signal waveform diagrams applied to unselected scanning electrodes. 3A and 3d are information signal waveform diagrams applied to selected signal electrodes. FIGS. 3A and 3e are information signal waveform diagrams applied to unselected signal electrodes. Figure 3 B, a
is a waveform diagram of the voltage applied to the liquid crystal of pixel A. FIGS. 3B and 3B are waveform diagrams of voltages applied to the liquid crystal of pixel B. FIG. FIGS. 3B and 3C are waveform diagrams of voltages applied to the liquid crystal of pixel c. FIGS. 3B and 3D are waveform diagrams of voltages applied to the liquid crystal of pixel D. FIG. 4 is a graph showing changes in drive stability due to changes in the absolute value k of the ratio of the electric signal V 1 applied to the scanning electrode and the electric signal ±V 2 applied to the signal electrode. FIG. 5 is a schematic plan view of a liquid crystal-light shutter as an example of a preferable application of the driving method of the present invention. 11...Liquid crystal element, 12...Scanning electrode group, 12
a...Selected scan electrode, 12n...Unselected scan electrode, 13...Signal electrode group, 13s...
Selected signal electrode, 13n... unselected signal electrode, 33... liquid crystal aligned in the first stable state, 33'... liquid crystal aligned in the second stable state,
34...Upward dipole moment P, 34'...
Downward dipole moment P', 41...pixel, 42
...Scanning electrode group, 43...Signal electrode group.
Claims (1)
極群と信号電極群との間に強誘電性液晶を配置
し、前記走査電極群と信号電極群との交差点にマ
トリクス画素を形成してなり、走査電極に走査選
択信号を印加し、該走査選択信号が第1位相と第
2位相とで、走査非選択電極への印加電圧を基準
として、それぞれ一方極性電圧と他方極性電圧と
を有し、選択された走査電極上の画素に対して、
第1位相で強誘電性液晶の一方の閾値電圧を越え
た電圧を与えて第1の配向状態を形成した画素
と、第2位相で他方の閾値電圧を越えた電圧を与
えて第2の配向状態を形成した画素とによつて画
像を形成する液晶装置であつて、 前記選択された走査電極と前記信号電極群のう
ちの選択された信号電極との交差部に印加する電
圧振幅が選択されていない走査電極と前記選択さ
れた信号電極との交差部に印加する電圧振幅の2
倍を超えることを特徴とする液晶装置。 2 更に、前記選択された走査電極と前記信号電
極群のうちの選択されていない信号電極との交差
部に印加する電圧振幅を、前記選択された走査電
極と選択された信号電極との交差部に印加する電
圧振幅の1/1.2以下に設定する特許請求の範囲
第1項記載の液晶装置。[Claims] 1. A device comprising a scanning electrode group and a signal electrode group, a ferroelectric liquid crystal is arranged between the scanning electrode group and the signal electrode group, and an intersection between the scanning electrode group and the signal electrode group. A scanning selection signal is applied to the scanning electrode, and the scanning selection signal has a first phase and a second phase, each having one polarity voltage with respect to the voltage applied to the scanning non-selection electrode. and the other polarity voltage, for the pixel on the selected scan electrode,
In the first phase, a voltage exceeding the threshold voltage of one of the ferroelectric liquid crystals is applied to form a first alignment state, and in the second phase, a voltage exceeding the threshold voltage of the other ferroelectric liquid crystal is applied to form a second alignment state. A liquid crystal device that forms an image by pixels forming a state, wherein a voltage amplitude is selected to be applied to an intersection between the selected scanning electrode and a selected signal electrode of the signal electrode group. 2 of the voltage amplitude applied to the intersection of the selected signal electrode and the selected signal electrode.
A liquid crystal device characterized by more than double the 2. Furthermore, the voltage amplitude applied to the intersection between the selected scan electrode and a signal electrode not selected from the signal electrode group is changed to the voltage amplitude applied to the intersection between the selected scan electrode and the selected signal electrode. The liquid crystal device according to claim 1, wherein the voltage amplitude is set to 1/1.2 or less of the voltage amplitude applied to the liquid crystal device.
Priority Applications (42)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP13871083A JPS6031121A (en) | 1983-07-30 | 1983-07-30 | Driving method of optical modulating element |
US06/598,800 US4655561A (en) | 1983-04-19 | 1984-04-10 | Method of driving optical modulation device using ferroelectric liquid crystal |
DE3448306A DE3448306C2 (en) | 1983-04-19 | 1984-04-18 | |
DE3448304A DE3448304C2 (en) | 1983-04-19 | 1984-04-18 | |
DE3448303A DE3448303C2 (en) | 1983-04-19 | 1984-04-18 | |
DE3448305A DE3448305C2 (en) | 1983-04-19 | 1984-04-18 | |
DE3448307A DE3448307C2 (en) | 1983-04-19 | 1984-04-18 | |
GB08410068A GB2141279B (en) | 1983-04-19 | 1984-04-18 | Method of driving optical modulation device |
DE19843414704 DE3414704A1 (en) | 1983-04-19 | 1984-04-18 | METHOD FOR DRIVING AN OPTICAL MODULATING DEVICE |
FR8406275A FR2544884B1 (en) | 1983-04-19 | 1984-04-19 | METHOD FOR CONTROLLING AN OPTICAL MODULATION DEVICE |
GB08619692A GB2180385B (en) | 1983-04-19 | 1986-08-13 | Liquid crystal apparatus |
GB08619691A GB2180384B (en) | 1983-04-19 | 1986-08-13 | Driving display devices |
GB08619831A GB2180386B (en) | 1983-04-19 | 1986-08-14 | Liquid crystal apparatus |
GB08712391A GB2191623B (en) | 1983-04-19 | 1987-05-27 | Liquid crystal apparatus |
GB08712392A GB2190530B (en) | 1983-04-19 | 1987-05-27 | Liquid crystal apparatus |
US07/139,162 US5448383A (en) | 1983-04-19 | 1987-12-21 | Method of driving ferroelectric liquid crystal optical modulation device |
US07/557,643 US5418634A (en) | 1983-04-19 | 1990-07-25 | Method for driving optical modulation device |
SG5291A SG5291G (en) | 1983-04-19 | 1991-01-31 | Liquid crystal apparatus |
SG6591A SG6591G (en) | 1983-04-19 | 1991-02-07 | Liquid crystal apparatus |
SG6191A SG6191G (en) | 1983-04-19 | 1991-02-07 | Liquid crystal apparatus |
SG6491A SG6491G (en) | 1983-04-19 | 1991-02-07 | Liquid crystal apparatus |
SG10391A SG10391G (en) | 1983-04-19 | 1991-02-21 | Liquid crystal apparatus |
SG116/91A SG11691G (en) | 1983-04-19 | 1991-02-23 | Method of driving optical modulation device |
HK708/91A HK70891A (en) | 1983-04-19 | 1991-09-05 | Liquid crystal apparatus |
HK705/91A HK70591A (en) | 1983-04-19 | 1991-09-05 | Liquid crystal apparatus |
HK706/91A HK70691A (en) | 1983-04-19 | 1991-09-05 | Liquid crystal apparatus |
HK715/91A HK71591A (en) | 1983-04-19 | 1991-09-05 | Method of driving optical modulation device |
HK707/91A HK70791A (en) | 1983-04-19 | 1991-09-05 | Liquid crystal apparatus |
HK709/91A HK70991A (en) | 1983-04-19 | 1991-09-05 | Liquid crystal apparatus |
US08/440,321 US5812108A (en) | 1983-04-19 | 1995-05-12 | Method of driving optical modulation device |
US08/444,899 US5548303A (en) | 1983-04-19 | 1995-05-19 | Method of driving optical modulation device |
US08/444,898 US5825390A (en) | 1983-04-19 | 1995-05-19 | Method of driving optical modulation device |
US08/444,746 US5592192A (en) | 1983-04-19 | 1995-05-19 | Method of driving optical modulation device |
US08/465,090 US5831587A (en) | 1983-04-19 | 1995-06-05 | Method of driving optical modulation device |
US08/462,974 US5886680A (en) | 1983-04-19 | 1995-06-05 | Method of driving optical modulation device |
US08/465,357 US5696526A (en) | 1983-04-19 | 1995-06-05 | Method of driving optical modulation device |
US08/462,978 US5790449A (en) | 1983-04-19 | 1995-06-05 | Method of driving optical modulation device |
US08/463,780 US5621427A (en) | 1983-04-19 | 1995-06-05 | Method of driving optical modulation device |
US08/465,225 US5565884A (en) | 1983-04-19 | 1995-06-05 | Method of driving optical modulation device |
US08/465,058 US5696525A (en) | 1983-04-19 | 1995-06-05 | Method of driving optical modulation device |
US08/463,781 US5841417A (en) | 1983-04-19 | 1995-06-05 | Method of driving optical modulation device |
US08/863,598 US6091388A (en) | 1983-04-13 | 1997-05-27 | Method of driving optical modulation device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP13871083A JPS6031121A (en) | 1983-07-30 | 1983-07-30 | Driving method of optical modulating element |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS6031121A JPS6031121A (en) | 1985-02-16 |
JPS6246845B2 true JPS6246845B2 (en) | 1987-10-05 |
Family
ID=15228313
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP13871083A Granted JPS6031121A (en) | 1983-04-13 | 1983-07-30 | Driving method of optical modulating element |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS6031121A (en) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS61245142A (en) * | 1985-04-23 | 1986-10-31 | Canon Inc | Liquid crystal optical element |
JPS626226A (en) * | 1985-07-02 | 1987-01-13 | Semiconductor Energy Lab Co Ltd | Liquid crystal display device |
JPS6232424A (en) * | 1985-08-05 | 1987-02-12 | Canon Inc | Method for driving liquid crystal element |
JP2626973B2 (en) * | 1995-10-30 | 1997-07-02 | セイコー電子工業株式会社 | Ferroelectric liquid crystal electro-optical device |
JP4791311B2 (en) * | 2006-09-29 | 2011-10-12 | マスプロ電工株式会社 | Electronic device case and electronic device |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS515993A (en) * | 1974-07-03 | 1976-01-19 | Suwa Seikosha Kk | |
JPS5311171A (en) * | 1976-07-19 | 1978-02-01 | Mitsubishi Plastics Ind Ltd | Packing for gas-liquid contact |
JPS56757A (en) * | 1979-06-15 | 1981-01-07 | Nippon Telegr & Teleph Corp <Ntt> | Terminal unit for diversity of car telephone |
JPS56107216A (en) * | 1980-01-08 | 1981-08-26 | Clark Noel A | Liquid crystal electrooptical device and production thereof |
JPS5757718A (en) * | 1980-09-25 | 1982-04-07 | Mitsui Toatsu Chem Inc | Production of polyamide/polyamide-acid block copolymer |
-
1983
- 1983-07-30 JP JP13871083A patent/JPS6031121A/en active Granted
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS515993A (en) * | 1974-07-03 | 1976-01-19 | Suwa Seikosha Kk | |
JPS5311171A (en) * | 1976-07-19 | 1978-02-01 | Mitsubishi Plastics Ind Ltd | Packing for gas-liquid contact |
JPS56757A (en) * | 1979-06-15 | 1981-01-07 | Nippon Telegr & Teleph Corp <Ntt> | Terminal unit for diversity of car telephone |
JPS56107216A (en) * | 1980-01-08 | 1981-08-26 | Clark Noel A | Liquid crystal electrooptical device and production thereof |
US4367924A (en) * | 1980-01-08 | 1983-01-11 | Clark Noel A | Chiral smectic C or H liquid crystal electro-optical device |
JPS5757718A (en) * | 1980-09-25 | 1982-04-07 | Mitsui Toatsu Chem Inc | Production of polyamide/polyamide-acid block copolymer |
Also Published As
Publication number | Publication date |
---|---|
JPS6031121A (en) | 1985-02-16 |
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