JPS61223793A - Driving of liquid crystal matrix display panel - Google Patents
Driving of liquid crystal matrix display panelInfo
- Publication number
- JPS61223793A JPS61223793A JP6340685A JP6340685A JPS61223793A JP S61223793 A JPS61223793 A JP S61223793A JP 6340685 A JP6340685 A JP 6340685A JP 6340685 A JP6340685 A JP 6340685A JP S61223793 A JPS61223793 A JP S61223793A
- Authority
- JP
- Japan
- Prior art keywords
- liquid crystal
- voltage
- display panel
- driving
- period
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Liquid Crystal (AREA)
- Liquid Crystal Display Device Control (AREA)
Abstract
(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.
Description
【発明の詳細な説明】
(産業上の利用分野)
本発明は低消費電力、かつ良好なコントラストで大規模
表示を実現できる液晶マトリクス表示パネルの駆動方法
に関するものである。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for driving a liquid crystal matrix display panel that can realize large-scale display with low power consumption and good contrast.
(従来の技術)
従来、ドツトマトリクス表示の液晶パネルでは、ねじれ
マチック液晶(以下、TN液晶と略す)を、電圧平均化
法なる方式で駆動することが広く行なわれている。(Prior Art) Conventionally, in dot matrix display liquid crystal panels, twisted matic liquid crystals (hereinafter abbreviated as TN liquid crystals) have been widely driven by a voltage averaging method.
電圧平均化法は、TN液晶の電気光学特性が印加される
電圧の実効値に依存することを前提とし、液晶には交流
電圧が印加すること、かつ半選択期間および非選択期間
に絵素を印加される電圧を平均化するという制限のもと
に、点灯絵素と非点灯絵素に印加される実効値電圧の比
が最大になるように導かれたものである。The voltage averaging method is based on the premise that the electro-optical properties of the TN liquid crystal depend on the effective value of the applied voltage, and that an alternating current voltage is applied to the liquid crystal, and that picture elements are applied during the half-selection period and the non-selection period. Under the restriction that the applied voltages are averaged, the ratio of the effective value voltages applied to the lit picture elements and the non-lit picture elements is maximized.
電圧平均化法による駆動方法を説明する。第3図に示す
ように、走査電極31を一定期間ごとに線順次に選択し
1選択された走査電極上に存する点灯絵素32に対応す
る信号電極33には選択電圧を、非点灯絵素34に対応
する信号電極33には非選択電圧をそれぞれに印加する
ことにより、点灯絵素と非点灯絵素に印加する電圧に差
をつけている。A driving method using the voltage averaging method will be explained. As shown in FIG. 3, the scanning electrodes 31 are line-sequentially selected at regular intervals, and a selection voltage is applied to the signal electrode 33 corresponding to the lit picture element 32 existing on one selected scanning electrode, and the selected voltage is applied to the non-lit picture element 32. By applying a non-selection voltage to each of the signal electrodes 33 corresponding to the signal electrodes 34, a difference is made between the voltages applied to the lit picture elements and the non-lit picture elements.
電圧平均化法における選択及び非選択期間での走査電圧
と信号電圧を第7図(a)、 (b)に示す。ここで、
R1,R3は選択期間、R2,R4は非選択期間の走査
電圧であり、 CI、C3は選択期間、C2,C4は非
選択期間における信号電圧である。波形はすべて矩形波
である。Scanning voltages and signal voltages during selection and non-selection periods in the voltage averaging method are shown in FIGS. 7(a) and 7(b). here,
R1 and R3 are scanning voltages during the selection period, R2 and R4 are scanning voltages during the non-selection period, CI and C3 are signal voltages during the selection period, and C2 and C4 are signal voltages during the non-selection period. All waveforms are square waves.
上記駆動方法においては、a=JN+l (Nは走査電
極数)としたとき、点灯および非点灯絵素をとり、この
とき、最高の表示コントラストが得られる。In the above driving method, when a=JN+l (N is the number of scanning electrodes), lit and non-lit picture elements are taken, and at this time, the highest display contrast is obtained.
(特公昭57−57718号公報:P、M、ALT、P
、PLESHKO,IEEETRANS ELECT
RON DEVICES、Vol、ED−21,Nn
2.Feb。(Special Publication No. 57-57718: P, M, ALT, P
, PLESHKO, IEEEETRANS ELECT
RON DEVICES, Vol, ED-21, Nn
2. Feb.
(発明が解決しようとする問題点)
我々の実験によると、液晶表示パネルに印加する電圧の
実効値を一定としながら、その周波数を高くしていくと
液晶表示パネルの輝度が変化し、無電界時の表示輝度に
近付いた。その変化は、数キロヘルツ以上で著しくなっ
た。第4図にその一例を示す。液晶の誘電率が、印加電
圧の周波数が高くなるにつれて、低くなるならば上記の
現象は自ら生ずるが、測定に使用した液晶は、上記測定
周波数域において一定であることが確かめられた。(Problem to be solved by the invention) According to our experiments, when the effective value of the voltage applied to the liquid crystal display panel is kept constant and its frequency is increased, the brightness of the liquid crystal display panel changes and The display brightness is close to that of the hour. The changes were significant above a few kilohertz. An example is shown in FIG. If the dielectric constant of the liquid crystal decreases as the frequency of the applied voltage increases, the above phenomenon will occur by itself, but it was confirmed that the liquid crystal used in the measurement was constant in the measurement frequency range.
そこで、上記の現象の原因として、液晶表示パネルの電
気回路的特性が考えられる。第5図に、液晶表示パネル
の絵素部分に対応する等価回路を示す。絵素の両端間に
V、の電圧が印加されるとき、液晶層に印加される実効
値電圧九は、
と表わされる。ここで、CL、RLは液晶層の電気容量
51及び抵抗52であり、Roは電極抵抗や配向膜など
の直列抵抗53であり、また、ω=2πf、fは印加電
圧の周波数である。Therefore, the electrical circuit characteristics of the liquid crystal display panel are considered to be the cause of the above phenomenon. FIG. 5 shows an equivalent circuit corresponding to a picture element portion of a liquid crystal display panel. When a voltage of V is applied across the picture element, the effective value voltage 9 applied to the liquid crystal layer is expressed as follows. Here, CL and RL are the capacitance 51 and resistance 52 of the liquid crystal layer, Ro is the series resistance 53 such as electrode resistance or alignment film, and ω=2πf, f is the frequency of the applied voltage.
式(1)より、周波数が高くなる程、液晶層に印加され
る実効値電圧■4は減する。すなわち、絵素の表示輝度
は、無電界時での輝度に近付くことになる。From equation (1), as the frequency becomes higher, the effective value voltage (4) applied to the liquid crystal layer decreases. That is, the display brightness of the picture element approaches the brightness in the absence of an electric field.
ところで、電圧平均化法において、選択期間に対応する
周波数は走査電極数が100程度になると数キロヘルツ
となる。また、矩形波であるので、高調波成分の寄与は
無視できない。そこで、先に述べたように、実際の液晶
表示パネルでは高い周波数での電圧減衰が大きいので、
その駆動波形に高調波成分を有する電圧平均化法におい
ては、電圧の減衰があり、消費電力に関して不利な状態
となっているという問題点を有していた。By the way, in the voltage averaging method, the frequency corresponding to the selection period becomes several kilohertz when the number of scanning electrodes is about 100. Furthermore, since it is a rectangular wave, the contribution of harmonic components cannot be ignored. Therefore, as mentioned earlier, in actual liquid crystal display panels, voltage attenuation is large at high frequencies, so
The voltage averaging method in which the drive waveform includes harmonic components has the problem of voltage attenuation, which is disadvantageous in terms of power consumption.
本発明の目的は上記問題点に鑑み、低消費電力かつ良好
なコントラストで大規模表示可能な液晶マトリクス表示
パネルの駆動方法を提供することである。SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to provide a method for driving a liquid crystal matrix display panel that can display a large-scale display with low power consumption and good contrast.
(問題点を解決するための手段)
上記問題点を解決するために本発明の液晶マトリクス表
示パネルの駆動方法は1次表に示すような変数で各状態
の電圧の波高値を表わすことにすれば
Vira(t)=V’ct(t)=l:VaSinωt
とき+、i == 2のとき−をとる)を満足すること
を特徴とするものである。(Means for Solving the Problems) In order to solve the above problems, the method for driving the liquid crystal matrix display panel of the present invention uses variables as shown in the first table to represent the peak value of the voltage in each state. For example, Vira(t)=V'ct(t)=l:VaSinωt
(+ when i == 2, - when i == 2).
(作 用)
本発明は上記した方式の通り、駆動波形を正弦波化する
ことにより、矩形波を用いる電圧平均化法での駆動波形
に比して低周波化することにより。(Function) As described above, the present invention converts the drive waveform into a sine wave, thereby lowering the frequency compared to the drive waveform in the voltage averaging method using a rectangular wave.
高周波(数キロヘルツ以上)の電圧の減衰が大きいとい
う、液晶表示パネルの電気回路的性質にもかかわらず、
液晶層に印加される電圧はほとんど減衰を受けることは
なくなる。このことは、消費電力を考えたとき、有利な
条件となる。Despite the electrical circuit nature of the liquid crystal display panel, which has a large attenuation of voltage at high frequencies (several kilohertz or higher),
The voltage applied to the liquid crystal layer will hardly be attenuated. This is an advantageous condition when considering power consumption.
また、この駆動法によるオン絵素およびオフ絵素に印加
する電圧の実効値比の最大値は、走査電値は、電圧平均
化法のそれと同じである。Further, the maximum value of the effective value ratio of the voltage applied to the ON picture element and the OFF picture element according to this driving method and the scanning voltage value are the same as those of the voltage averaging method.
デユーティ1/128. a = J128+ 1のと
きの、絵素に印加される電圧のフーリエ解析を行なった
。Duty 1/128. Fourier analysis of the voltage applied to the picture element when a = J128+1 was performed.
第6図(a)は電圧平均化法、第6図(b)は本発明の
駆動方法の場合である。明らかに、本発明の駆動方法の
波形は低周波化されている。FIG. 6(a) shows the case of the voltage averaging method, and FIG. 6(b) shows the case of the driving method of the present invention. Obviously, the waveform of the driving method of the present invention has a lower frequency.
(実施例)
本発明の一実施例の液晶マトリクス表示パネルの駆動方
法について、第1図および第2図に基づいて説明する。(Example) A method for driving a liquid crystal matrix display panel according to an example of the present invention will be described based on FIGS. 1 and 2.
第1図は1本発明の第1の実施例における。液晶マトリ
クス表示パネルの駆動方法を示すものである。同図にお
いて1は走査電極、2は信号電極である。その駆動方法
は走査電極を順次選択し。FIG. 1 shows a first embodiment of the present invention. This shows a method of driving a liquid crystal matrix display panel. In the figure, 1 is a scanning electrode, and 2 is a signal electrode. The driving method is to sequentially select the scanning electrodes.
選択された走査電極上に存する点灯絵素11に対応する
信号電極には選択電圧を、非点灯絵素12に対応する信
号電極には非選択電圧をそれぞれ印加することにより、
点灯および非点灯絵素に印加する電圧に差をつけ、コン
トラストを出す。この際、印加する電圧は第8図の関係
に従うものとする。By applying a selection voltage to the signal electrode corresponding to the lit picture element 11 existing on the selected scan electrode, and applying a non-selection voltage to the signal electrode corresponding to the non-lit picture element 12,
Contrast is created by applying different voltages to lit and non-lit pixels. At this time, the voltage to be applied shall follow the relationship shown in FIG.
以上のように本実施例によれば、駆動波形を正弦波的に
することにより、波形を低周波化し、電圧の減衰を小さ
く押えることができる。As described above, according to this embodiment, by making the drive waveform sinusoidal, the frequency of the waveform can be lowered, and voltage attenuation can be kept small.
なお、上記実施例において、全走査電極を線順次に2回
選択することにより、液晶に交流電圧が印加するように
していたが、第2図、第9図に示すように1選択期間内
に印加する電圧を交流化してもよい。In the above embodiment, AC voltage was applied to the liquid crystal by selecting all scanning electrodes twice line-sequentially, but as shown in FIGS. 2 and 9, AC voltage was applied to the liquid crystal within one selection period. The applied voltage may be changed to alternating current.
(発明の効果)
本発明によれば、駆動波形として正弦波を用い波形を低
周波化することにより、高い周波数(数キロヘルツ以上
)の電圧に対する減衰が大きいという、液晶表示パネル
の電気回路的性質にも影響を受けず、各絵素に減衰され
ない電圧を印加することができる効果がある。(Effects of the Invention) According to the present invention, by using a sine wave as the driving waveform and lowering the frequency of the waveform, the electric circuit property of the liquid crystal display panel is such that attenuation is large for voltages at high frequencies (several kilohertz or more). This has the effect of being able to apply an unattenuated voltage to each picture element without being affected by this.
第1図は、本発明の第1の実施例における。液晶マトリ
クス表示パネルの駆動方法の動作を説明する図、第2図
は、本発明の第2の実施例における駆動方法の動作を説
明する図、第3図は従来の駆動方法である電圧平均化法
の動作を説明する図、第4図は液晶表示パネル輝度の(
印加電圧の)周波数依存性を示す図、第5図は液晶表示
パネルに対応する等価電気回路図、第6図(a) 、
(b)は、駆動電圧波形のフーリエ振幅を表わす図であ
り、(a)は従来の方法(電圧平均化法)を示す図、(
b)は本発明の駆動方法に対応する図、第7図(a)、
(b)は電圧平均化法の電圧波形、信号波形および液
晶に印加される電圧波形を示す図、第8図は本発明の第
1の実施例における走査電圧と信号電圧および液晶に印
加される電圧波形を示す図、第9図は本発明の第2の実
施例における走査電圧と信号電圧および液晶に印加され
る電圧波形を示す図である。
1 、21.31・・・走査電極、2,22.33・・
・信号電極、 11,23,32・・・点灯絵素、
12,24,34・・・非点灯絵素、51・・・液晶
層の電気容量、52・・・液晶層の電気抵抗、53・・
・電極抵抗。
特許出願人 松下電器産業株式会社
第1図
1−一一±量電極
2−一一信号電る
11− 点虐帷素
12−−一非A、it#、亀
!!2 図
第3 図
第4図
同波数(Hz)
第5m
第6図
(a)
(b)
0m jK 数(Hz) 30720第 7 ci
](a)
(1)!圧平均[遣の電旦」1杉乏青・信号波後筒 7
図 (b)
(2)液晶にEn加される雪上うpL形8 図
(2)シ皮晶に1力0ぐえるti浪形
図FIG. 1 shows a first embodiment of the present invention. A diagram explaining the operation of the driving method for a liquid crystal matrix display panel, FIG. 2 is a diagram explaining the operation of the driving method in the second embodiment of the present invention, and FIG. 3 is a diagram explaining the operation of the driving method of the conventional driving method. Figure 4 is a diagram explaining the operation of the method, and shows the brightness of the liquid crystal display panel (
Fig. 5 is an equivalent electric circuit diagram corresponding to a liquid crystal display panel, Fig. 6(a) is a diagram showing the frequency dependence (of applied voltage),
(b) is a diagram showing the Fourier amplitude of the drive voltage waveform, (a) is a diagram showing the conventional method (voltage averaging method), (
b) is a diagram corresponding to the driving method of the present invention, FIG. 7(a),
(b) is a diagram showing voltage waveforms, signal waveforms, and voltage waveforms applied to the liquid crystal in the voltage averaging method, and FIG. 8 is a diagram showing the scanning voltage, signal voltage, and voltage waveform applied to the liquid crystal in the first embodiment of the present invention. FIG. 9 is a diagram showing the scanning voltage, signal voltage, and voltage waveform applied to the liquid crystal in the second embodiment of the present invention. 1, 21.31... scanning electrode, 2, 22.33...
・Signal electrode, 11, 23, 32... lighting picture element,
12, 24, 34... Non-lighting picture element, 51... Electric capacity of liquid crystal layer, 52... Electric resistance of liquid crystal layer, 53...
・Electrode resistance. Patent Applicant: Matsushita Electric Industrial Co., Ltd. Figure 1 1-11 ± Volume Electrode 2-11 Signal Electrical 11- Point Massage Element 12--1 non-A, it#, turtle! ! 2 Figure 3 Figure 4 Wavenumber (Hz) 5m Figure 6 (a) (b) 0m jK Number (Hz) 30720 7th ci
](a) (1)! Pressure average [Ken-no-den-dan] 1 Sugi Hosei/Signal wave post-tube 7
Figure (b) (2) Snow upper pL shape 8 where En is added to the liquid crystal Figure (2) Ti wave shape diagram where one force 0 is applied to the liquid crystal
Claims (3)
N本の走査電極群を形成し、他方には前記方向と直交す
る方向にM本の信号電極群を形成し、前記基板間に液晶
層を有し、両電極群を駆動する電源回路を具してなるN
行M列の液晶マトリクス表示パネルに於いて、一定期間
τ中に走査電極に印加する電圧の波高値を選択時にはV
^i_r_a(t)(ここでi=1、2)、非選択時に
はV^i_r_n(t)とし、前記期間中に信号電極に
印加する電圧の波高値を選択時にはV^i_c_s(t
)、非選択時にはV^i_c_n(t)とし、前記期間
中に点灯絵素に印加される電圧の振幅をV_0Sin(
ωt)(ここで0≦t≦τ、ω=π/τ)として、さら
に線順次に選択する走査電極が一巡するまでの期間(第
1ピリオド)においては添字iが1で定義される電圧を
印加し、引き続いて、次に走査電極の選択が一巡するま
での期間(第2ピリオド)においては添字iが2で定義
される電圧を印加し、前記二つの期間が交互に繰り返さ
れるものとし、各々の電圧の波高値が V^i_r_a(t)=V^i_c_s(t)±V_0
SinωtV^i_r_n(t)=V^i_c_s(t
)±(V_0/a)SinωtV^i_c_n(t)=
V^i_c_s(t)±(2V_0/a)Sinωt(
ここでaは実数、符号はi=1のとき+、i=2のとき
−をとる) を満足することを特徴とする液晶マトリクス表示パネル
の駆動方法。(1) N scanning electrode groups aligned in one direction are formed on one of the opposing surfaces of a pair of substrates, M signal electrode groups are formed on the other side in a direction orthogonal to the said direction, and the substrate N having a liquid crystal layer therebetween and comprising a power supply circuit for driving both electrode groups.
In a liquid crystal matrix display panel with rows and M columns, when selecting the peak value of the voltage to be applied to the scanning electrode during a certain period τ, V
^i_r_a(t) (where i = 1, 2), when not selected, it is set to V^i_r_n(t), and when the peak value of the voltage applied to the signal electrode during the period is selected, it is set to V^i_c_s(t).
), when not selected, V^i_c_n(t), and the amplitude of the voltage applied to the lit picture element during the period is V_0Sin(
ωt) (here, 0≦t≦τ, ω=π/τ), and the subscript i is the voltage defined by 1 during the period (first period) until the scanning electrodes selected line-sequentially complete one cycle. Then, during the period (second period) until the selection of the scan electrode goes through one cycle, a voltage defined by the subscript i of 2 is applied, and the two periods are alternately repeated, The peak value of each voltage is V^i_r_a(t)=V^i_c_s(t)±V_0
SinωtV^i_r_n(t)=V^i_c_s(t
)±(V_0/a)SinωtV^i_c_n(t)=
V^i_c_s(t)±(2V_0/a) Sinωt(
A method for driving a liquid crystal matrix display panel, characterized in that a is a real number and the sign is + when i=1 and - when i=2.
る特許請求の範囲第(1)項記載の液晶マトリクス表示
パネルの駆動方法。(2) A method for driving a liquid crystal matrix display panel according to claim (1), characterized in that a is set to a value near √N+1.
inωtと設定することを特徴とする特許請求の範囲第
(1)項記載の液晶マトリクス表示パネルの駆動方法。(3) |V^1_c_s-V^2_c_s|=V_0S
The method for driving a liquid crystal matrix display panel according to claim 1, wherein inωt is set.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6340685A JPS61223793A (en) | 1985-03-29 | 1985-03-29 | Driving of liquid crystal matrix display panel |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6340685A JPS61223793A (en) | 1985-03-29 | 1985-03-29 | Driving of liquid crystal matrix display panel |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS61223793A true JPS61223793A (en) | 1986-10-04 |
Family
ID=13228386
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP6340685A Pending JPS61223793A (en) | 1985-03-29 | 1985-03-29 | Driving of liquid crystal matrix display panel |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS61223793A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6215533B1 (en) | 1996-05-17 | 2001-04-10 | Sharp Kabushiki Kaisha | Ferroelectric liquid crystal driving using square wave and non-square wave signals |
JP4508313B2 (en) * | 1998-08-05 | 2010-07-21 | ヒューレット・パッカード・カンパニー | Liquid crystal display |
-
1985
- 1985-03-29 JP JP6340685A patent/JPS61223793A/en active Pending
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6215533B1 (en) | 1996-05-17 | 2001-04-10 | Sharp Kabushiki Kaisha | Ferroelectric liquid crystal driving using square wave and non-square wave signals |
JP4508313B2 (en) * | 1998-08-05 | 2010-07-21 | ヒューレット・パッカード・カンパニー | Liquid crystal display |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
KR930016811A (en) | LCD and its driving method | |
JPH0320715A (en) | Method of addressing matrix-array type liquid-crystal cell | |
KR970017136A (en) | Driving method of liquid crystal display element | |
EP0500328A2 (en) | Display apparatus | |
JPS61223793A (en) | Driving of liquid crystal matrix display panel | |
KR970060032A (en) | Liquid crystal devices that alternately use different types of vibration waveforms | |
KR940010748A (en) | Driving method of strong dielectric liquid crystal panel | |
KR100296835B1 (en) | Addressed ferroelectric liquid crystal display | |
JP4564178B2 (en) | Liquid crystal display element | |
JP2002328399A (en) | Liquid crystal display element and its driving method | |
JPH0448367B2 (en) | ||
JPH11272246A (en) | Liquid crystal device and method and device for addressing liquid crystal device | |
JPS623228A (en) | Driving method of liquid crystal display device | |
JPH0448366B2 (en) | ||
JPS60150032A (en) | Driving method of liquid crystal matrix panel | |
JPH04276794A (en) | Liquid crystal display device | |
JPH01267619A (en) | Method of driving liquid crystal display element | |
JPH07261149A (en) | Liquid crystal device | |
KR940007504B1 (en) | Driving method for ferro electric lcd particle | |
JPS61118727A (en) | Liquid crystal matrix display device | |
JPS62287226A (en) | Driving method for liquid crystal display device | |
JPS6146934A (en) | Driving method of liquid crystal matrix display panel | |
JPH063645A (en) | Drive method for liquid crystal panel and drive method for optical shutter array | |
JPH04237018A (en) | Driving method for electrooptical display device | |
JPS61158399A (en) | Driving of liquid crystal matrix display panel |