JPS60151615A - Driving method of liquid-crystal display device - Google Patents
Driving method of liquid-crystal display deviceInfo
- Publication number
- JPS60151615A JPS60151615A JP802984A JP802984A JPS60151615A JP S60151615 A JPS60151615 A JP S60151615A JP 802984 A JP802984 A JP 802984A JP 802984 A JP802984 A JP 802984A JP S60151615 A JPS60151615 A JP S60151615A
- Authority
- JP
- Japan
- Prior art keywords
- line
- liquid crystal
- signal
- voltage
- time
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Liquid Crystal (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、各表示絵素に表示スイッチング用薄膜トラン
ジスタ（以下ＴＰＴと略す）を設けたドツトマトリック
ス表示デバイスを線順次動作させる場合の液晶表示デバ
イスの駆動法に関するものである。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to driving of a liquid crystal display device when a dot matrix display device in which each display pixel is provided with a display switching thin film transistor (hereinafter abbreviated as TPT) is operated line-sequentially. It is about law.
従来例の構成とその問題点
液晶表示でバイスは、低消費電力性、ポータプル性の特
徴を有しているため、電卓あるいは時計等の表示として
現在市場に完全に定着している。Conventional Structures and Problems Liquid crystal displays have the characteristics of low power consumption and portability, and are now completely established in the market as displays for calculators, watches, and the like.
さらに昨今、０ム化が進む中で、高密度表示デバイスと
しての液晶ドツトマトリックス表示デバイスの実現が強
く望まれており、走査線数を増加さ−せるために、各表
示絵素にスイッチング用ＴＰＴ −を非晶質シリコンあ
るいは、ポリシリコンＣａ５ｅ等で作製したドツトマト
リックス表示デバイスカ開発、製品化されつつある。Furthermore, with the recent trend toward zero-millimeter display, there is a strong desire to realize liquid crystal dot matrix display devices as high-density display devices, and in order to increase the number of scanning lines, each display pixel is equipped with switching TPT - Dot matrix display devices made of amorphous silicon, polysilicon Ca5e, etc. are being developed and commercialized.
従来のスイッチングＴＰＴ付ドツトマトリックス液晶表
示の駆動を、第１図に示すようなドツトマトリックス液
晶表示デバイスの等何回路に対し走査ライン１ （・ａ
ｍ ＋ ＋ ２Ｌｍ ＋ ａｍ＋、（”’ ） に入れ
るゲート電圧を第２図に、信号ライン２（・・・ｂＭ−
＋。The driving of a conventional dot matrix liquid crystal display with a switching TPT is performed by scanning line 1 (・a
Figure 2 shows the gate voltage applied to m + + 2Lm + am+, (''), and the signal line 2 (...bM-
+.
ｂＭ！ｂＭ＋１・・・・）に入れるドレインＮＥを第３
図に示す。第２図に示すように、第ｎフレームで信号ラ
イン２に印加される信号電圧の極性を正とすると、第ｎ
＋１フレームでは信号電圧の極性を反転させ負にする。bM! bM+1...) drain NE to be placed in the third
As shown in the figure. As shown in FIG. 2, if the polarity of the signal voltage applied to the signal line 2 in the nth frame is positive, then
In the +1 frame, the polarity of the signal voltage is inverted and made negative.
すなわち、各フレームごとに極性を反転させる。これは
、液晶の劣化を防ぐためのものである。この時の液晶に
加わる電圧は、スイツチング用ＴＰＴのｏｆｆ抵抗が、
液晶の抵抗より大きい場合、ある走査線ラインが選択さ
れ、次のフレームで選択される１で、はぼ液晶自体の時
定数で放電していく。液晶表示デバイスの画面の上端部
と下端部の走査ラインにかかる電圧を、第４図の実線５
と６のそれぞれに示す。液晶駆動電圧は、液晶にかかる
電圧の実効値であるため、時間に対する電圧を示すカー
ブの面積であると考えてよい。したがって、スイッチン
グ用ＴＰＴのｏｆｆ抵抗が大きい場合、表示画面の上端
部と下端部との走査ラインにかかる電圧実効値は等しい
ため、輝度むらのない良好な画面が得られる。しかし、
従来のこの駆動法で動作させると、以下に示す理由によ
り、画面の上部、下部で輝度むらを生じるという欠点が
ある。今一絵素だけの等価回路榛、第６図（ａ）、 （
ｂｌに示す。第６図（ｂ）は、スイッチング用ＴＦＴを
抵抗ＲＴ７と考えたもので、ゲート走査ラインが選択さ
れたときと、非選択の時とで抵抗が変化するものと考え
る。That is, the polarity is reversed for each frame. This is to prevent deterioration of the liquid crystal. The voltage applied to the liquid crystal at this time is determined by the off resistance of the switching TPT.
If the resistance is greater than the resistance of the liquid crystal, a certain scanning line is selected, and when 1 is selected in the next frame, it is discharged according to the time constant of the liquid crystal itself. The voltage applied to the scanning lines at the top and bottom of the screen of a liquid crystal display device is shown by the solid line 5 in FIG.
and 6, respectively. Since the liquid crystal driving voltage is the effective value of the voltage applied to the liquid crystal, it can be considered to be the area of a curve showing voltage versus time. Therefore, when the off resistance of the switching TPT is large, the effective value of the voltage applied to the scanning line at the upper end and the lower end of the display screen is equal, so that a good screen without uneven brightness can be obtained. but,
When operated using this conventional driving method, there is a drawback that brightness unevenness occurs at the top and bottom of the screen for the reasons described below. Equivalent circuit of only Imaichi picture element, Figure 6 (a), (
Shown in bl. In FIG. 6(b), it is assumed that the switching TFT is a resistor RT7, and the resistance changes depending on whether the gate scanning line is selected or not.
非選択時に液晶が保持している電圧ＶＬはとなる。The voltage VL held by the liquid crystal when not selected is as follows.
ここで、ｒ ＝ ＣＬ ・（Ｒｏｒｒ／ ＲＬ ）１ である。Here, r = CL・(Rorr/RL)1 It is.
今の場合、ゲートの浮遊容量、ソースドレイン間の浮遊
容量の影響は無視している。式（２）の第１項かられか
るように、非選択時の液晶にかかっている電圧ＶＬは、
他の走査線が選択されている時に送り出されている信号
電圧Ｖｎ （７５影響を受けることになる。画面を完全
点灯した場合が、上端部と下端部の輝度差が最大となり
、それは第６図に示すように、上端部のそのフレームで
送り出される正の信号の影響により実効電圧が持ち上が
った電圧分１０と、下端部が次のフレームで極性が反転
した負の信号電圧の影響による実効電圧の目減り分１１
との差で決まる。−フレームの時間間隔ｉＴとすると上
端部の実効電圧の増加分Δｖｕ１０と下端部の実効電圧
減少分Δｖｄ１１は、τ
ΔｖｕンΔＶ６ 夕Ｔ−ｖ。（１−ｅ ７ ） 式（３
）したがって上下端部の画面の輝度差ΔＵは、ΔＵ−Δ
Ｖ ＋Δｖｄ
χ２Ｔ−Ｖｏ（１−ｅ−τ） 式（５）である。ＴＰＴ
のｏｆｆｆｆ抵抗Ｒ０ｆｆと液晶の抵抗ＲＬ ｇとの大
小関係で非選択時の信号の影響が決まる。ｏｆｆ抵抗Ｒ
８ｒｄ’十分Ｒｔ＋より大きいと式（４）＋ （５）よ
りΔＵ−＝Ｊｏとなり信号の影響はなくなる。In this case, the effects of stray capacitance at the gate and stray capacitance between source and drain are ignored. As can be seen from the first term of equation (2), the voltage VL applied to the liquid crystal when not selected is:
This will be affected by the signal voltage Vn (75) sent out when another scanning line is selected.When the screen is completely lit, the difference in brightness between the top and bottom ends is maximum, as shown in Figure 6. As shown in , the effective voltage is increased by 10 due to the effect of the positive signal sent in that frame at the top end, and the effective voltage is increased by the effect of the negative signal voltage whose polarity is reversed in the next frame at the bottom end. Loss amount 11
It is determined by the difference between - If the frame time interval is iT, then the increase in effective voltage Δvu10 at the upper end and the decrease in effective voltage Δvd11 at the lower end are τ Δvun ΔV6 T−v. (1-e7) Formula (3
) Therefore, the brightness difference ΔU between the upper and lower ends of the screen is ΔU − Δ
V +Δvd χ2T-Vo(1-e-τ) Formula (5). TPT
The influence of the signal when not selected is determined by the magnitude relationship between the off resistance R0ff and the liquid crystal resistance RL g. off resistance R
If 8rd' is sufficiently larger than Rt+, ΔU-=Jo from equations (4)+(5), and the influence of the signal disappears.
しかしＲｏｆｆが小さいと非選択絵素の信号が走査線の
異なる選択絵素の信号から受ける影響が太きくなる。However, if Roff is small, the signal of a non-selected picture element will be greatly influenced by the signal of a selected picture element of a different scanning line.
発明の目的
本発明の目的は、ＴＰＴのｏｆｆ抵抗Ｒ８ｆｆ から受
ける非選択時に他の信号から受ける影響を軽減し、画面
の上部と下部との輝度むらを小さくする液晶表示デバイ
スの駆動法を提供するものである。OBJECTS OF THE INVENTION It is an object of the present invention to provide a method for driving a liquid crystal display device that reduces the influence of other signals during non-selection from the off-resistance R8ff of TPT and reduces uneven brightness between the top and bottom of the screen. It is something.
発明の構成
本発明の液晶表示デバイスの駆動法は、ドツトマトリッ
クス液晶表示デバイスで、各表示絵素にスイッチング’
ＬＦＴ’ｉ設けた表示パネルを線順次動作させる際、信
号極性を走査線−ライン選択ごと、あるいは一フレーム
中の数ライン選択ごとに反転させることを特徴とし、表
示画面の輝度むらを減少させる。Composition of the Invention The driving method of the liquid crystal display device of the present invention is a dot matrix liquid crystal display device in which each display pixel has a switching element.
When the display panel provided with LFT'i is operated line-sequentially, the signal polarity is inverted every scanning line-to-line selection or every several line selections in one frame, thereby reducing brightness unevenness on the display screen.
実施例の説明
一実施例としてモノクロ信号の場合を考える０第７図に
示す如く、信号ラインに入れる極性を走査線−ライン選
択ごとに反転させる。今簡単のために、画面全面点灯の
場合の信号を入れる。この時液晶画素にかかる電圧は、
第８図に示す如く、ＴＰＴのｏｆｆ抵抗で他の信号から
受ける影響は極性が反転するごとに、＋、−の電圧の持
ち上がりをするために、結果として、画面上部と下部と
の保持電圧差はキャン七ルされ々くなってしまう。DESCRIPTION OF THE EMBODIMENT As an example, consider the case of a monochrome signal.0 As shown in FIG. 7, the polarity input to the signal line is inverted for each scanning line-to-line selection. Now, for simplicity, add a signal for when the entire screen is lit. At this time, the voltage applied to the liquid crystal pixel is
As shown in Figure 8, the influence of other signals on the off resistance of the TPT causes the + and - voltages to rise each time the polarity is reversed, resulting in a difference in the held voltage between the top and bottom of the screen. It's becoming more and more popular.
また、カラー表示で、Ｒ，Ｇ、Ｂがニラインに渡ってい
る場合は、ニラインごとに極性全反転させればよい。な
お、−ラインあるいはニラインで極性を反転さ・せるの
が難しい時は、−フレームの中で数ラインごとに極性を
反転させればよい。ただし、フレームごとには、同一ラ
インにかかる信号極性は反転していかなければならない
。Further, in a color display, when R, G, and B are spread over two lines, the polarity may be completely reversed for every two lines. Note that if it is difficult to invert the polarity at the - line or the second line, it is sufficient to invert the polarity every few lines within the - frame. However, the polarity of the signal applied to the same line must be reversed for each frame.
発明の効果
−Ｆ記のように一ラインごとに極性を反転させると」二
輪部と下端部との液晶にかかる保持電圧の差はかなり減
少出来、輝度むらが少なくなる。この方式で保持電圧の
差が一番犬きくなるのは、−ラインごとに点灯させた時
、第９図に示すような信号を入れた場合である。このと
きの信号電圧による液晶にかかる保持電圧への影響は、
従来例の式（６）で表わされた中でＴに一！−を代入し
た式に相当する。よって、画面の上端部と下端部との輝
度差ΔＵ′は、
一二一
ΔＵ’＝Ｔ−ｖｏ・（１６２τ） 式（６）となり、従
来例に較べ、
！
ΔＵ／ΔＩ］＝１／！（１＋８ ”τ） 式（７）だけ
減少出来る。したがって一ラインおきのパターンでも最
低でμ、最大具減少出来る。実際には、種々の信号が入
ってくるため、さらに干渉作用が働き、上述より減少出
来ることを実験で確認している。Effects of the Invention - When the polarity is reversed for each line as shown in F, the difference in the holding voltage applied to the liquid crystal between the two-wheeled part and the lower end can be considerably reduced, and uneven brightness can be reduced. In this method, the difference in holding voltage becomes the greatest when a signal as shown in FIG. 9 is applied when each - line is turned on. The effect of the signal voltage on the holding voltage applied to the liquid crystal at this time is:
One in T in the formula (6) of the conventional example! This corresponds to an expression in which - is substituted. Therefore, the luminance difference ΔU' between the top and bottom edges of the screen is expressed as: 121 ΔU'=T-vo・(162τ) Equation (6), and compared to the conventional example, ! ΔU/ΔI]=1/! (1+8 ”τ) It can be reduced by Equation (7). Therefore, even with every other line pattern, the minimum μ can be reduced by the maximum. In reality, since various signals come in, further interference effects work, and from the above We have confirmed through experiments that this can be reduced.
第１図はスイッチング１“ＦＴ付ドツトマトリックス液
晶表示デバイスの等価回路図、第２図は一走査ラインに
加えられる電圧と時間の関係を示す図、第３図は信号ラ
インに加えられるドレイン電圧と時間の関係を示す図、
第４図は表示画面の上端部と下端部との液晶画素が保持
している電圧と時間の関係を示す図、第５図（ａ）、
（ｂ）は同素子の−の全面点灯信号が入った時の表示画
面の上端部と下端部の液晶画素が影響を受ける電圧と時
間の関係を示す図、第７図は一走査ラインごと一フレー
ムごとに信号電圧の極性を反転させる液晶表示の駆動法
を示す図、第８図は画面全点灯を第７図に示す駆動した
時の上端部と下端部の液晶画素が保持している電圧と時
間との関係を示す図、第９図は一走査線おきに縞状パタ
ーンを出すだめの信号箱、圧を示す図である。
１・・・・・・走査ライン、２・・・・・・信号ライン
、３・・・・・・スイッチングＴＦＴ、４・・・・・・
液晶画素、５・・・・・・画面−］二端の液晶画素の信
号保持電圧、６・・・・・・画面下端の液晶画素の信号
保持電圧、７・・・・・・ＴＦＴｉ抵抗ＲＴにおき換え
て考えたもの、８・・・・・・液晶画素の容量、９・・
・・・・液晶画素の抵抗、１０・・・・・・画面上端の
液晶画素の信号保持電圧が他の選択走査ラインの信号電
圧から影響を受けて増分した電圧分、１１・・・・−・
画面下端の液晶画素の信号保持電圧が他の選択走査ライ
ンの信号電圧から影響を受けて減少′した電圧分。
代理人の氏名 弁理士 中 尾 敏 男 ほか１名第
１ 図
り
第２図
第 ３ 図Figure 1 is an equivalent circuit diagram of a dot matrix liquid crystal display device with switching 1"FT, Figure 2 is a diagram showing the relationship between the voltage applied to one scanning line and time, and Figure 3 is a diagram showing the relationship between the voltage applied to one scanning line and the drain voltage applied to the signal line. A diagram showing the relationship between time,
Figure 4 is a diagram showing the relationship between the voltage held by the liquid crystal pixels at the upper and lower ends of the display screen and time, Figure 5 (a),
(b) is a diagram showing the relationship between voltage and time to which the liquid crystal pixels at the upper and lower ends of the display screen are affected when the negative full-lighting signal of the same element is input. Figure 8 is a diagram showing the driving method of a liquid crystal display that inverts the polarity of the signal voltage every frame. Figure 8 shows the voltage held by the liquid crystal pixels at the upper and lower ends when the screen is fully lit as shown in Figure 7. FIG. 9 is a diagram showing the signal box and pressure for producing a striped pattern every other scanning line. 1...Scanning line, 2...Signal line, 3...Switching TFT, 4...
Liquid crystal pixel, 5...Screen-] Signal holding voltage of the liquid crystal pixel at the two ends, 6... Signal holding voltage of the liquid crystal pixel at the bottom edge of the screen, 7...TFTi resistance RT What I thought in place of 8... Capacity of liquid crystal pixel, 9...
...Resistance of the liquid crystal pixel, 10...Voltage increased by the signal holding voltage of the liquid crystal pixel at the top of the screen being influenced by the signal voltage of other selected scanning lines, 11...-・
The amount by which the signal holding voltage of the liquid crystal pixel at the bottom of the screen is reduced due to the influence of the signal voltage of other selected scanning lines. Name of agent: Patent attorney Toshio Nakao and 1 other person
1 Diagram Figure 2 Figure 3
Claims (1)
スイッチング用薄膜トランジスターを設けた表示パネル
を線順次動作させる際、信号極性を走査線−ライン選択
ごと、あるいは数ライン選択ごとに反転させること′ｆ
ｆ：特徴とした液晶表示デバイス駆動法。In a dot matrix liquid crystal display device, when a display panel in which each display pixel is provided with a switching thin film transistor is operated line-sequentially, the signal polarity is inverted every time a scanning line is selected or every few lines are selected.
f: Featured liquid crystal display device driving method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP802984A JPS60151615A (en) | 1984-01-19 | 1984-01-19 | Driving method of liquid-crystal display device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP802984A JPS60151615A (en) | 1984-01-19 | 1984-01-19 | Driving method of liquid-crystal display device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS60151615A true JPS60151615A (en) | 1985-08-09 |
Family
ID=11681911
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP802984A Pending JPS60151615A (en) | 1984-01-19 | 1984-01-19 | Driving method of liquid-crystal display device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60151615A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5107353A (en) * | 1989-08-28 | 1992-04-21 | Kabushiki Kaisha Toshiba | Driving method of liquid crystal display |
| US5253091A (en) * | 1990-07-09 | 1993-10-12 | International Business Machines Corporation | Liquid crystal display having reduced flicker |
| US5296847A (en) * | 1988-12-12 | 1994-03-22 | Matsushita Electric Industrial Co. Ltd. | Method of driving display unit |
| US5436747A (en) * | 1990-08-16 | 1995-07-25 | International Business Machines Corporation | Reduced flicker liquid crystal display |
| JPH08234707A (en) * | 1996-01-18 | 1996-09-13 | Sanyo Electric Co Ltd | Driving circuit for liquid crystal display device |
| US5706023A (en) * | 1988-03-11 | 1998-01-06 | Matsushita Electric Industrial Co., Ltd. | Method of driving an image display device by driving display materials with alternating current |
| US6400350B1 (en) | 1997-11-13 | 2002-06-04 | Mitsubishi Denki Kabushiki Kaisha | Method for driving liquid crystal display apparatus |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54106193A (en) * | 1978-02-08 | 1979-08-20 | Sharp Corp | Driving method for matrix type liquid crystal display unit |
| JPS5814890A (en) * | 1981-07-20 | 1983-01-27 | セイコーエプソン株式会社 | Driving of liquid crystal display |
-
1984
- 1984-01-19 JP JP802984A patent/JPS60151615A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54106193A (en) * | 1978-02-08 | 1979-08-20 | Sharp Corp | Driving method for matrix type liquid crystal display unit |
| JPS5814890A (en) * | 1981-07-20 | 1983-01-27 | セイコーエプソン株式会社 | Driving of liquid crystal display |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5706023A (en) * | 1988-03-11 | 1998-01-06 | Matsushita Electric Industrial Co., Ltd. | Method of driving an image display device by driving display materials with alternating current |
| US5296847A (en) * | 1988-12-12 | 1994-03-22 | Matsushita Electric Industrial Co. Ltd. | Method of driving display unit |
| US5107353A (en) * | 1989-08-28 | 1992-04-21 | Kabushiki Kaisha Toshiba | Driving method of liquid crystal display |
| US5253091A (en) * | 1990-07-09 | 1993-10-12 | International Business Machines Corporation | Liquid crystal display having reduced flicker |
| US5436747A (en) * | 1990-08-16 | 1995-07-25 | International Business Machines Corporation | Reduced flicker liquid crystal display |
| JPH08234707A (en) * | 1996-01-18 | 1996-09-13 | Sanyo Electric Co Ltd | Driving circuit for liquid crystal display device |
| US6400350B1 (en) | 1997-11-13 | 2002-06-04 | Mitsubishi Denki Kabushiki Kaisha | Method for driving liquid crystal display apparatus |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101196860B1 (en) | Liquid crystal display | |
| KR101279596B1 (en) | Array substrate and display apparatus having the same | |
| JP3240367B2 (en) | Active matrix type liquid crystal image display | |
| JP3069930B2 (en) | Liquid crystal display | |
| JP2016539365A (en) | Liquid crystal panel driving circuit, driving method, and liquid crystal display device | |
| JPH11161246A (en) | Liquid crystal display device and driving method thereof | |
| JPH07270754A (en) | Liquid crystal display device | |
| JP3914639B2 (en) | Liquid crystal display | |
| JPS60151615A (en) | Driving method of liquid-crystal display device | |
| JPS6395420A (en) | Driving method for active matrix type liquid crystal display device | |
| JP4326242B2 (en) | Liquid crystal display | |
| JP2000020033A (en) | Liquid crystal display device | |
| KR100885018B1 (en) | Liquid crystal display and driving method thereof | |
| JPH06266313A (en) | Liquid crystal matrix display device | |
| JPS63172192A (en) | Driving of active matrix type liquid crystal panel | |
| JPH06266318A (en) | Driving method for active matrix type liquid crystal device | |
| JPH0916131A (en) | Liquid crystal display device and driving method for liquid crystal display element | |
| EP0851270A2 (en) | Active matrix addressed liquid crystal display apparatus | |
| JP2957920B2 (en) | Display device | |
| JPH0727339B2 (en) | Driving method of matrix type liquid crystal display device | |
| JPH11326868A (en) | Liquid crystal display device | |
| KR20030088647A (en) | Liquid crystal display | |
| JPH06118910A (en) | Method for driving liquid crystal display device | |
| JPH10282934A (en) | Driving method for liquid crystal display device | |
| KR100879214B1 (en) | Liquid crystal display device |