503334 A7 B7 5550twf . doc/006 五、發明說明（,\ 本發明是有關於一種液晶顯示器之控制方法，且特別 是有關於一種薄膜電晶體型液晶顯示器之控制方法，更特 別關於一種可以縮短關機時放電之時間的操作方法。 液晶顯示器（liquid crystal display，LCD)，係利用外加 電場及熱之作用，使得液晶分子由特定的初期分子配列變 化至其他的分子配列狀態，伴隨著此分子配列之液晶顯示 器之複折射性（birefringence)、旋光性、二色性、光散亂性 等等之光學性質變化，而轉換成視覺之變化。此外，LCD 更具有低操作電壓、低消耗電力等之優點，使其適合以大 尺度積體（large scale Integrated LSI)電路來加以驅動。目 前，由於薄膜電晶體（thin film ..transistor，TFT)技術的發展 與進步，使用TFT來做爲LCD之顯像像素(pixel)已經越來 越普及。 如第1圖所示，其繪示一部份一般LCD結構。以TFT 型LCD而言，係於一透明基板上，由複數個TFT電晶體 所構成的陣列，而每一個TFT電晶體均代表一個像素。然 而，根據TFT電晶體之特性，其在關閉時之汲極源極電流 (IDS，放電電流）與一般之MOSFET電晶體低很多，一般的 數値大約爲l〇_n〜l〇_12安培(A)以下。但這也造成TFT型LCD 的一個缺點。即’在LCD關機後，由於放電電流小，源 極與汲極之間的電壓VSD之放電時間（discharge time，td)變 長，而造成LCD上有影像殘留的現象6 請參考第2圖，其繪示習知之TFT型液晶顯示器，於 關機後，每一個像素（即每一個TFT電晶體）之閘極汲極電 3 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） «1*§11 n mMme I ϋ aemmm · * —i «I IB IB n -1 I ^l:OJ> mm· mm· *·ιι·τ mb 線， (請先閱讀背面之注意事項再填寫本頁) 經濟部智慧財產局員工消費合作社印製 503334 5550twf.doc/006 A7 B7 經濟部智慧財產局員工消費合作社印製 五、發明說明（>) 壓（V(;D)、源極汲極電壓（VSD)與共用電極電壓（VeQM)與時間 之關係曲線圖◦如圖示，在tztdf，關閉LCD。故，可以看 出源極汲極電壓VSD要經過很長的放電時間td才降爲0V。 因此，若放電電流IDS越小，VSD的放電時間就越長， 而造成影像殘留的時間越長。 、 因此本發朋係提出一種減少液晶顯示器之殘留影像的 方法，用以在·; LCD關機時，施加脈衝電壓至TFT電晶體 .之電極，以縮短液晶_內儲存電荷的放電時間。 本發明所揭露之減少液晶顯示器之殘留影像的方 法，其簡述如下： 一種減少液晶顯示器之殘留影像的方法，此液晶顯示 器包括由複數個電晶體構成的陣列，形成於一透明基底 上，每一電晶體均具有閘極、汲極與源極。一液晶耦接於 源極與共用電極之間。本發明之方法係當液晶顯示器關機 時，於液晶中之閘極、汲極或共用電極施加一脈衝電壓， 用以縮短在各個電晶體之汲極與源極間之源極汲極電壓的 放電時間。藉此，可縮短儲存於液晶中的電荷的放電時間。 因爲源極汲極電壓放電時間縮短，所以關機後LCD之影 像的殘留時間可以大爲縮短。 ^ 爲讓本發明之上述目的、特徵、和優點能更明顯易懂， 下文特舉較佳實施例，並配合所附圖式，作詳細說明如下： 圖式之簡單說明： 第1圖繪示液晶顯示器中構成像素成分之薄膜電晶體 的陣列示意圖； -----*·!裝 I!訂--！線' (請先閲讀背面之注意事項再填寫本頁) 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） 經濟部智慧財產局員工消費合作社印製 503334 5550twf.doc/006 Ά _B7_ 五、發明說明（3 ) 第2圖繪示習知之液晶顯示器在關機前後，代表各像 素之薄膜電晶體的閘極汲極電壓、源極汲極電壓與共用電 極電壓之電壓曲線變化圖； 第3圖繪示實施本發明之方法的一種電路示意圖； 第4A圖繪示以脈衝電壓施加於共用電極.，以實施本 發明之方法時，於液晶顯示器關機前後之閘極汲極電壓與 源極汲極電壓的電壓曲線變化圖； 第4B圖繪示以脈衝壓施加於閘極，以實施本發明 之方法時，於液晶顯示器關機前後之閘極汲極電壓、源極 汲極電壓與共用電極電壓的電壓曲線變化圖； 第4C圖繪示以脈衝電壓施加於汲極，以實施本發明 之方法時，於液晶顯示器關機前後之閘極汲極電壓、源極 汲極電壓與共用電極電壓的電壓曲線變化圖；以及 第5圖繪示一種可以實施本發明之方法的電路架構示 意圖。 標號說明_· 10脈衝產生器 20脈衝產生器 22開關裝置 24 TFT電晶體之電極 -實施例 . 本發明之減少液晶顯示器之殘留影像的方法的槪念， 係於液晶顯不益關機時’施加一'脈衝於構成液晶威不益之 薄膜電晶體的其中一個電極，用以瞬間增加每一薄膜電晶 體之汲極源極之間的放電電流，同時亦增加汲極源極或閘 極汲極之間的電壓，藉此關機時汲極源極之放電時間可以 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） I _----- I------— 裝---I----訂---------線 — (請先閱讀背面之注意事項再填寫本頁) 503334 經濟部智慧財產局員工消費合作社印製 5550twf.doc/006 五、發明說明（Y) 縮短，因而減少影像殘留的時間◦在以下之實施例中，均 以TFT電晶體做爲說明例。 如第3圖所示，其繪示構成LCD像素陣列之電晶體的 其中一個。一個TFT電晶體具有一閘極、汲極與源極。一 液晶LC係耦接於共用電極COM與源極之間。此外，還可 以與液晶LC並聯一個電容器Cst。一般而言，液晶LC亦 具有一等效时電容値C^：。 達成本發明之目的的脈衝電壓可以由一脈衝產生器10 來產生。此脈衝產生器10在接收到LCD之關機訊號時， 變產生一脈衝訊號.。由於此脈衝訊號施加於TFT電晶體之 閘極、汲極或共用電極均可以達到目的，以下將以這三種 情況來加以說明。 在第3圖之脈衝產生器10之輸出訊號係輸入至共用 電極COM端。當選用不同的電極時，脈衝產生器10之輸 出訊號便必須更換成輸入到閘極端或汲極端。 首先，討論脈衝電壓係施加於共用電極端時的情況。 第4 A圖則繪示在此情況下，.於液晶顯示器關機前後之閘 極汲極電壓Ve[D與源極汲極電壓VSD的電壓曲線變化圖。 在LCD關機後，在COM端施加一脈衝電壓Vpl。此 —脈衝電壓經由液晶LC與電容Cst之電容性耦合到TFT電 晶體的源極，這使得源極電壓Vs提高。由於源極電壓Vs 提高，源極汲極間電壓vSD也隨之增加，汲極源極電流IDS 亦跟著提高；亦即放電時間td便得以縮短。藉此，儲存於 液晶LC內之電荷便可以在短時間之內釋放。故，因爲習 I i I I f I I I I I I I · I I I I I I I ^ « — — IIIIII (請先閱讀背面之注意事項再填寫本頁) 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） 503334 5550twf.doc/006 A7 B7 五、發明說明（ί) 知之放電時間td太長所造成的殘留影像問題便可以解決。 (請先閱讀背面之注意事項再填寫本頁) 如第4A圖所示，於共用電極端施加一脈衝電壓Vpl， 源極汲極間電壓VSD也隨著產生一對應的脈衝電壓Vpl’。 由於Vpi’之脈衝寬度很短，因此源極汲極間電壓VSD可以 很快降至0V ;亦即，可以很快地釋放液晶LC內所儲存的 電荷。舉例說明之，此脈衝電壓Vpl之寬度可以約爲1秒 左右，在關機時，IDS亦跟著提高到10_η以上，或甚至更 高，故放電時間td可以縮短到1秒以下。 其次，當脈衝電壓係施加於TFT電晶體之閘極端時， 第4B圖則繪示在此情況下，於液晶顯示器關機前後之閘 極汲極電壓VijD與源極汲極電壓VSD的電壓曲線變化圖閘 極汲極電壓V(;D、源極汲極電壓VSD與共用電極電壓VeQM 的電壓曲線變化圖。 經濟部智慧財產局員工消費合作社印製 在LCD關機後，在閘極端施加一脈衝電壓Vp2(如可爲 一正脈衝）。此時，與Vas亦隨著增加，汲極源極電流 IDS亦跟著提高。亦即，這源極汲極間電壓VSD之放電速度 會加快；亦即，放電時間td便得以縮短。藉此，儲存於液 晶LC內之電荷便可以在短時間之內釋放。故，因爲習知 之放電時間td太長所造成的殘留影像問題便可以解決。 如第4B圖所示，於閘極端施加一脈衝電壓Vp2，閘極 極汲極間電壓V(;D也隨著產生一對應的脈衝電壓Vp2’。因 此，源極汲極間電壓VSD可以很快降至0V ;亦即，可以很 快地釋放液晶LC內所儲存的電荷。 最後，討論當脈衝電壓係施加於TFT電晶體之汲極端 7 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） 503334 5 5 5 0 t1 .d ο c / Ο Ο 6 Α7 Β7 五、發明說明（6 ) 時的情況。第4C圖則繪示液晶顯示器關機前後之閘極汲 極電壓V(:;D、源極汲極電壓VSD與共用電極電壓VeQM的電 壓曲線變化圖〜 在LCD關機後，在汲極端施加一脈衝電壓（如可爲一 負脈衝）。這使得VeiD增加，產生對應的脈衝電壓（在此例 爲一負脈衝），而汲極源極電流IDS亦跟著提高。亦即，這 •源極汲極間電壓VSD之放電速度會加快；亦即，放電時間 便得以縮短。藉此，儲存於液晶LC內之電荷便可以在 短時間之內釋放。故，因爲習知之放電時間td太長所造成 的殘留影像問題便可以解決。舉例說明之，此脈衝電壓Vp2 之寬度可以約爲1秒左右，在關機時，IDS亦跟著提高到l(Tn 以上，或甚至更高，故放電時間td可以縮短到1秒以下。 如第4C圖所示，於汲極端施加一負的脈衝電壓Vp3， 閘極極汲極間電壓VCD也隨著產生一對應的正脈衝電壓 請 先 閱 讀 背 意 事 項 再 填 % 本 頁503334 A7 B7 5550twf. Doc / 006 V. Description of the invention (, the invention relates to a control method of a liquid crystal display, and particularly to a control method of a thin film transistor type liquid crystal display, and more particularly to a method that can shorten the shutdown Liquid crystal display (LCD) is the use of an external electric field and heat to change the liquid crystal molecules from a specific initial molecular alignment to other molecular alignment states. The optical properties of birefringence, optical rotation, dichroism, and light scattering of liquid crystal displays are changed into changes in vision. In addition, LCDs have the advantages of low operating voltage and low power consumption. , Making it suitable for driving with large scale integrated LSI circuits. At present, due to the development and progress of thin film transistor (TFT) technology, TFT is used as the display of LCD Pixel (pixel) has become more and more popular. As shown in Figure 1, it shows a part of the general LCD structure. TFT For an LCD, it is an array of a plurality of TFT transistors on a transparent substrate, and each TFT transistor represents a pixel. However, according to the characteristics of the TFT transistor, its drain when turned off The source current (IDS, discharge current) is much lower than that of a general MOSFET transistor, and the general number is about 10_n ~ 10_12 amps (A). However, this also causes a disadvantage of the TFT LCD. That is, after the LCD is turned off, because the discharge current is small, the discharge time (td) of the voltage VSD between the source and the drain becomes longer, resulting in the phenomenon of image retention on the LCD. 6 Please refer to Figure 2, It shows the conventional TFT-type liquid crystal display. After shutdown, the gate drain of each pixel (that is, each TFT transistor). 3 This paper size applies to China National Standard (CNS) A4 (210 X 297 mm). ) «1 * §11 n mMme I ϋ aemmm · * —i« I IB IB n -1 I ^ l: OJ &mm; mm · mm · * · ιι · τ mb line, (Please read the precautions on the back before filling (This page) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 503334 5550twf.doc / 006 A7 B7 Printed by the Consumer Cooperatives of the Ministry of Intellectual Property Bureau V. Description of the invention (>) Voltage (V (; D), source-drain voltage (VSD), common electrode voltage (VeQM) and time-relationship curve diagrams as shown At tztdf, turn off the LCD. Therefore, it can be seen that the source drain voltage VSD drops to 0V after a long discharge time td. Therefore, if the discharge current IDS is smaller, the discharge time of the VSD is longer, and the longer the time for causing image sticking. Therefore, this post proposes a method for reducing the residual image of the liquid crystal display, which is used to apply a pulse voltage to the electrode of the TFT transistor when the LCD is turned off to shorten the discharge time of the stored charge in the liquid crystal. The method for reducing the residual image of a liquid crystal display disclosed in the present invention is briefly described as follows: A method for reducing the residual image of a liquid crystal display. The liquid crystal display includes an array of a plurality of transistors and is formed on a transparent substrate. A transistor has a gate, a drain, and a source. A liquid crystal is coupled between the source and the common electrode. In the method of the present invention, when the liquid crystal display is turned off, a pulse voltage is applied to a gate, a drain, or a common electrode in the liquid crystal to shorten the discharge of the source drain voltage between the drain and the source of each transistor. time. Thereby, the discharge time of the electric charge stored in the liquid crystal can be shortened. Because the drain time of the source-drain voltage is shortened, the residual time of the LCD image after shutdown can be greatly reduced. ^ In order to make the above-mentioned objects, features, and advantages of the present invention more comprehensible, the preferred embodiments are described below in detail with the accompanying drawings as follows: Brief description of the drawings: FIG. 1 shows Schematic diagram of the array of thin film transistors that make up the pixel components in a liquid crystal display; ----- * ·! 装 I !!-! LINE '(Please read the notes on the back before filling this page) This paper size applies the Chinese National Standard (CNS) A4 (210 X 297 mm) Printed by the Intellectual Property Bureau Staff Consumer Cooperative of the Ministry of Economic Affairs 503334 5550twf.doc / 006发明 _B7_ V. Description of the invention (3) Figure 2 shows the voltage curve of the gate-drain voltage, source-drain voltage, and common-electrode voltage of a conventional thin-film transistor before and after shutdown. Figure 3 shows a schematic diagram of a circuit for implementing the method of the present invention; Figure 4A shows a pulse voltage applied to a common electrode. When the method of the present invention is implemented, the gate-drain voltage and FIG. 4B shows the voltage curve of the source drain voltage. FIG. 4B shows the gate drain voltage, the source drain voltage and the The voltage curve of the common electrode voltage; FIG. 4C shows the gate voltage before and after the LCD is turned off when a pulse voltage is applied to the drain to implement the method of the present invention. Voltage, drain-source voltage and the common voltage curve of FIG electrode voltage; and FIG. 5 schematically shows a possible embodiment of the method of the circuit architecture of the present invention is shown intended. DESCRIPTION OF SYMBOLS _ · 10 pulse generator 20 pulse generator 22 switching device 24 TFT transistor electrode-embodiment. The idea of the method for reducing the residual image of the liquid crystal display of the present invention is applied when the liquid crystal display is not powered off. A 'pulse' is applied to one of the electrodes of the thin film transistor that constitutes the liquid crystal wafer, and is used to instantly increase the discharge current between the drain source of each thin film transistor, and also increase the drain source or gate drain. Between the voltage, so that the drain source drain time when shutting down can be applied to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) on this paper scale I _----- I ------ — Install --- I ---- Order --------- Line— (Please read the notes on the back before filling out this page) 503334 Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 5550twf.doc / Fifth, the description of the invention (Y) is shortened, so the time of image retention is reduced. In the following embodiments, TFT transistors are used as examples. As shown in Fig. 3, it shows one of the transistors constituting the LCD pixel array. A TFT transistor has a gate, a drain, and a source. A liquid crystal LC is coupled between the common electrode COM and the source. In addition, a capacitor Cst may be connected in parallel with the liquid crystal LC. Generally speaking, the liquid crystal LC also has an equivalent time capacitance 値 C ^ :. The pulse voltage for the purpose of the invention can be generated by a pulse generator 10. When the pulse generator 10 receives the shutdown signal from the LCD, it generates a pulse signal. Since this pulse signal can be applied to the gate, drain, or common electrode of a TFT transistor, the purpose can be achieved by the following three cases. The output signal of the pulse generator 10 in Fig. 3 is input to the common electrode COM terminal. When different electrodes are selected, the output signal of the pulse generator 10 must be replaced with an input to the gate or drain terminal. First, a case where a pulse voltage is applied to a common electrode terminal will be discussed. Figure 4A shows the voltage curve of the gate-drain voltage Ve [D and the source-drain voltage VSD before and after the LCD display is turned off in this case. After the LCD is turned off, a pulse voltage Vpl is applied to the COM terminal. This —the pulse voltage is capacitively coupled to the source of the TFT transistor via the liquid crystal LC and the capacitor Cst, which causes the source voltage Vs to increase. As the source voltage Vs increases, the source-drain voltage vSD also increases, and the drain-source current IDS also increases; that is, the discharge time td is shortened. Thereby, the charge stored in the liquid crystal LC can be discharged in a short time. Therefore, because Xi I i II f IIIIIII · IIIIIII ^ «— — IIIIII (Please read the precautions on the back before filling this page) This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) 503334 5550twf .doc / 006 A7 B7 V. Description of the Invention (ί) The problem of afterimage caused by too long discharge time td can be solved. (Please read the precautions on the back before filling this page) As shown in Figure 4A, a pulse voltage Vpl is applied to the common electrode terminal, and the source-drain voltage VSD also generates a corresponding pulse voltage Vpl ′. Because the pulse width of Vpi 'is short, the source-drain voltage VSD can be quickly reduced to 0V; that is, the charge stored in the liquid crystal LC can be quickly released. For example, the width of the pulse voltage Vpl can be about 1 second. When the power is turned off, the IDS also increases to more than 10_η, or even higher, so the discharge time td can be shortened to less than 1 second. Secondly, when the pulse voltage is applied to the gate terminal of the TFT transistor, FIG. 4B shows the voltage curve of the gate drain voltage VijD and the source drain voltage VSD before and after the LCD is turned off. Figure The voltage curve of gate drain voltage V (; D, source drain voltage VSD, and common electrode voltage VeQM. Printed after the LCD is turned off, a pulse voltage is applied to the gate terminal after the LCD is turned off. Vp2 (if it can be a positive pulse). At this time, as Vas increases, the drain-source current IDS also increases. That is, the discharge speed of the source-drain voltage VSD will be accelerated; that is, The discharge time td can be shortened. As a result, the charge stored in the liquid crystal LC can be released in a short time. Therefore, the problem of the residual image caused by the conventionally long discharge time td can be solved. As shown in Figure 4B It is shown that when a pulse voltage Vp2 is applied to the gate terminal, the gate-to-drain voltage V (; D also generates a corresponding pulse voltage Vp2 '. Therefore, the source-to-drain voltage VSD can be quickly reduced to 0V; That can be fast Ground discharges the charge stored in the liquid crystal LC. Finally, discuss when the pulse voltage is applied to the drain terminal of the TFT transistor 7 This paper size is applicable to China National Standard (CNS) A4 (210 X 297 mm) 503334 5 5 5 0 t1 .d ο c / Ο Ο 6 Α7 Β7 V. The situation in the description of the invention (6). Figure 4C shows the gate drain voltage V (:; D, source drain voltage VSD before and after the LCD is turned off). Variation of the voltage curve with the common electrode voltage VeQM ~ After the LCD is turned off, a pulse voltage (eg, a negative pulse) is applied to the drain terminal. This causes Veid to increase to generate a corresponding pulse voltage (a negative pulse in this example) ), And the drain-source current IDS also increases. That is, the discharge speed of the source-drain voltage VSD is accelerated; that is, the discharge time is shortened. As a result, the charge stored in the liquid crystal LC is reduced. It can be released in a short time. Therefore, the residual image problem caused by the conventionally long discharge time td can be solved. For example, the width of this pulse voltage Vp2 can be about 1 second. At shutdown, IDS Also mentioned As high as l (Tn, or even higher, the discharge time td can be shortened to less than 1 second. As shown in FIG. 4C, a negative pulse voltage Vp3 is applied to the drain terminal, and the gate-to-drain voltage VCD also varies with To generate a corresponding positive pulse voltage, please read the note before filling in this page
V p3 因此，源極汲極間電壓vSD可以很快降至ον ;亦即 可以很快地釋放液晶LC內所儲存的電荷。 經濟部智慧財產局員工消費合作社印製 由上所述可以明白，在LCD關機時，施加一脈衝電 壓於TFT電晶體之共用電極、閘極或汲極，均可以在提高 源極汲極電壓VSD以及源極汲極電流IDS，而使得VSD之放 電時間縮短。故，儲存於液晶LC內的電荷可以迅速地被 釋放，以減少LCD顯示器之影像殘留問題。舉例說明之， 此脈衝電壓Vp32寬度可以約爲1秒左右，在關機時，IDS 亦跟著提高到1〇~π以上，或甚至更高，故放電時間td可以 縮短到1秒以下。 本紙張尺度適用中國國家榡準（CNS)A4規格（210 X 297公釐） 503334 5550twf.d〇c/〇〇6 A7 B7 經濟部智慧財產局員工消費合作社印製 五、發明說明（◊) 第5圖繪示一種可以實施本發明之方法的電路架構示 意圖。第5圖所繪示的電路架構係說明脈衝電壓要施加於 哪一個電極’可以由LCD的生產者或使用者來自行調整。 在脈衝產生器20與TFT陣列24之間增加一個開關裝置 22 ’此開關装置22可以根據一選擇訊號SEL來選擇要將 脈衝電壓施加於閘極、汲極或共用電極上。上述之TFT陣 列的各個閘極、汲極與共用電極均透過該開關装置22連 接到脈衝產生器20。藉此，可以更有效地選擇最佳的電極 來施加脈衝電壓，以減少LCD關機後之殘留影像問題。 綜上所述’本發明之減少液晶顯示器之殘留影像的方 法與習知技術相較之下至少具有下列之優點與功效： 依據本發明之減少液晶顯示器之殘留影像的方法，在 LCD關機時，利用施加脈衝電壓於TFT電晶體之閘極、汲 極或共用電極上，以縮短TFT電晶體之源極汲極電壓的放 電時間。 綜上所述’雖然本發明已以較佳實施例揭露如上，然 其並非用以限定本發明，任何熟習此技藝者，在不脫離本 發明之精神和範圍內，當可作各種之更動與潤飾，因此本 發明之保護範圍當視後附之申請專利範圍所界定者爲準。 ^紙張尺度_帽_標準(CNS)A4規格（210 X 297公釐） — — — — — — — — ^ · I I I I I I (請先閱讀背面之注音？事項再填寫本頁)V p3 Therefore, the source-drain voltage vSD can be quickly reduced to ον; that is, the charge stored in the liquid crystal LC can be quickly released. Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs It can be understood from the above that when the LCD is turned off, applying a pulse voltage to the common electrode, gate or drain of the TFT transistor can increase the source drain voltage VSD And the source drain current IDS, so that the VSD discharge time is shortened. Therefore, the charge stored in the liquid crystal LC can be quickly discharged to reduce the problem of image sticking of the LCD display. As an example, the width of the pulse voltage Vp32 can be about 1 second. When the power is turned off, the IDS also increases to above 10 ~ π, or even higher, so the discharge time td can be shortened to less than 1 second. This paper size is applicable to China National Standard for Standards (CNS) A4 (210 X 297 mm) 503334 5550twf.doc / 〇〇6 A7 B7 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs FIG. 5 is a schematic diagram of a circuit architecture capable of implementing the method of the present invention. The circuit architecture shown in FIG. 5 illustrates which electrode 'to which the pulse voltage is applied can be adjusted by the LCD manufacturer or user. A switching device 22 is added between the pulse generator 20 and the TFT array 24. The switching device 22 can select a pulse voltage to be applied to the gate, the drain, or the common electrode according to a selection signal SEL. Each gate, drain, and common electrode of the above-mentioned TFT array is connected to the pulse generator 20 through the switching device 22. This makes it possible to more effectively select the best electrode to apply the pulse voltage to reduce the residual image problem after the LCD is turned off. In summary, the method of reducing the residual image of a liquid crystal display of the present invention has at least the following advantages and effects compared with the conventional technology: According to the method of reducing the residual image of a liquid crystal display according to the present invention, when the LCD is turned off, Applying a pulse voltage to the gate, drain, or common electrode of the TFT transistor to shorten the discharge time of the source-drain voltage of the TFT transistor. To sum up, 'Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Retouching, so the scope of protection of the present invention shall be determined by the scope of the attached patent application. ^ Paper size_cap_standard (CNS) A4 specification (210 X 297 mm) — — — — — — — — — ^ I I I I I I (Please read the note on the back? Matters before filling out this page)