200941432 九、發明說明： 【發明所屬之技術領域】 本發明係關於一種顯示器屏幕顯示控制系統及其控制 方法。 【先前技術】 液晶顯示裝置因具有重量輕、體積小、耗電低等優點， 已廣泛應用於各種資訊、通訊及消費性電子產品中。 請參閲圖1，其係一種先前技術液晶顯示裝置結構示意 ®圖。該液晶顯示裝置10包括一液晶顯示面板11。該液晶顯 示面板11包括一像素電極111、一公共電極112、一液晶層 113、一上偏光片114及一下偏光片115。該上偏光片114及 該下偏光片115相對設置，且偏振方向垂直。該像素電極111 置於該上偏光片114及該下偏光片115之間，該公共電極112 置於該像素電極111及該下偏光片115之間，該液晶層113 置於該像素電極111及該公共電極112之間。該像素電極111 ❿及該公共電極112均採用透明導電材料製成，例如氧化銦 錫、氧化銦鋅等。 在該像素電極111上施加一灰階電壓，在該公共電極112 上施加一公共電壓，從而在該像素電極111及該公共電極112 之間形成一電壓差。該電壓差以電場之形式控制該液晶層 113内液晶分子（圖未示）之偏轉，並結合該上偏光片114及 該下偏光片115以控制光線從該液晶顯示面板11之通過 量，進而達到顯示晝面之目的。 爲實現不同之畫面顯示，需要改變該像素電極111及該 200941432 公共電極112之間之電壓差。先前技術中通常是由驅動電路 產生不同之灰階電壓施加至該像素電極111，而提供一恆定 之預設公共電壓至該公共電極112以實現。 然，通常在該液晶顯示裝置10使用過程中，隨著其開 啓時間之增加，該液晶顯示面板11之溫度等會發生變化， 液晶顯示面板11内部會產生直流電場等，同時又因製做該 公共電極112之材質多為不良導體，這將導致該公共電極 112上實際有效之公共電壓值相對於我們所需要之預設公共 電壓值產生漂移。該公共電極112上有效公共電壓之漂移現 象將導致晝面閃爍、晝面粘滯等現象，從而使該液晶顯示裝 置10之顯示品質降低，故，該液晶顯示裝置10之顯示品質 不穩定。 【發明内容】 有鑒於此，提供一種具有穩定顯示品質之液晶顯示裝置 實為必要。 同時，提供一種具有穩定顯示品質之液晶顯示裝置之驅 動方法亦為必要。 一種液晶顯示裝置，其包括一液晶顯示面板及一為該液 晶顯示面板提供公共電壓之公共電壓產生電路。該公共電壓 產生電路包括一微處理單元、一計時器、一電壓調整電路及 一查找表。該微處理單元分別電連接至該計時器、該電壓調 整電路及該查找表。該計時器用於記錄該液晶顯示裝置之持 續工作時間。該查找表用於存儲每一持續工作時間對應之最 佳公共電壓值。該微處理單元用於每隔一段時間依據該持續 9 200941432 工作時間於該查找表中獲取對應之最佳公共電壓值，並控制 該電壓調整電路產生最佳公共電壓。 "" 一種液晶顯示裝置驅動方法，其包括·· a•提供—包括一 公共電極之液晶顯示面板；b.向該公共電極輸入公共電壓， 並每隔一段時間依據該液晶顯示面板之持續工作時間調整 該公共電壓之值。 相較於先前技術，由於本發明液晶顯示裝置之公共電壓 ❹產生電路设置有計時器、微處理單元、查找表及電壓調整電 路，該微處理單s每隔-端時間於該查找表中讀取對應之最 佳公共電壓值，並控制該電壓調整電路產生相應之最佳公共 電壓，從而校正該液晶顯示面板中公共電極之有效公共電 壓減J該有效公共電壓漂移程度，從而避免因該有效公丘 電壓漂移而導致之畫面_、晝面枯滯等現象，使該液晶顯 示裝置之顯示品質穩定。 相較於先前技術’由於本發明液晶顯示裝置驅動方法包 ❹，向該公共電極輸人公共電壓，並每隔—段時間依據該液晶 如面板之持續工作時間調整該公共電壓，從而不斷校正該 該液晶顯示面板内公共電極具有之有效公共電壓，使其因各 生之漂移大幅減少’從而較大程度上避免因該有效 :、電壓漂移而導致之晝面_、晝面㈣等問題，進而使 δ亥液晶顯不裝置之顯示品質較爲穩定。 【實施方式】 喷參閲圖2 ’其係本發明液晶顯示裝置第—實施方式之 電路結構方框示意圖。該液曰 政液日日顯不裝置20包括一液晶顯示 200941432 面板201及一驅動電路202。該驅動電路202包括一產生公 共電壓之公共電壓產生電路210及一輸出灰階電壓之資料驅 動電路220，分別為該液晶顯示面板201提供公共電壓及灰 階電壓等驅動訊號。 該公共電壓產生電路210包括一計時器211、一微處理 單元212、一查找表213、一電壓調整電路214及一輸出端 215。該微處理單元212分別與該計時器211、該查找表213、 該電壓調整電路214電連接，該輸出端215分別與該電壓調 ®整電路214及該液晶顯示面板201電連接。 在該液晶顯示裝置20開啓時，該計時器211開始計時， 並且每隔一段時間向該微處理單元212發出一記錄有該液晶 顯示裝置20持續工作時間T之時間訊號。在該液晶顯示裝 置20關閉時，將計時器211所記錄之持續工作時間T設置 為零。該持續工作時間T亦係該液晶顯示面板201之持續工 作時間。該微處理單元212具有信息處理功能，其可以判斷 0由計時器211發送出之時間訊號，並依據其内部預先設定之 程序進行相應處理，之後向該電壓調整電路214發出調整訊 號。該調整訊號係脈衝方波，其佔空比由該微處理單元212 調整決定。該查找表213記錄有與該液晶顯示裝置20持續 工作時間T所對應之最佳公共電壓值。該電壓調整電路214 係一脈寬調變（Pulse Width Modulation，PWM)式開關穩壓電 源電路，其根據該微處理單元212發出之調整訊號產生並調 整公共電壓，同時藉由該輸出端215緩衝後將公共電壓輸出 至該液晶顯示面板201。 11 200941432 該查找表213所記錄之與該液晶顯示裝置20持續工作 時間T所對應之最佳公共電壓值可在該液晶顯示裝置20處 於測試階段時這樣獲得： 步驟A，記錄該液晶顯示裝置20在開啓時刻T0=0時之 最佳公共電壓； 假設該液晶顯示面板20之公共電極所需要之預設公共 電壓為V，則於該液晶顯示裝置20開啓時調整該公共電壓 產生電路210輸出之公共電壓值使該公共電極之有效公共電 Ο V壓值為V，此時得到該公共電壓產生電路210輸出之公共電 壓值為V0，同時該液晶顯示裝置20持續工作時間Τ=Τ0， 該電壓數值V0即為該液晶顯示裝置20在持續工作時間 T=T0時刻之最佳公共電壓值。將該電壓數值V0及時間數值 TO記錄於該查找表213中。 步驟B，記錄該液晶顯示裝置20工作一段時間後之最 佳公共電壓； q 在該液晶顯示裝置20工作一段時間後，如該持續工作 時間T=T1時，監測該公共電極上之有效公共電壓是否變 化，此時有兩種情況： 一、 該公共電極上之有效公共電壓未發生變化。此時， 於該查找表213中記錄時間數值Τ1，並記錄與該持續工作 時間Τ=Τ1相對應之電壓數值為VI，其中V1=V0。 二、 該公共電極上之有效公共電壓發生變化。此時，調 整該公共電壓輸出電路210之輸出電壓，使該公共電極之有 效公共電壓為V。此時該公共電壓210之輸出電壓值為VI。 12 200941432 將該時間數值T1及電壓數值VI對應記錄於該查找表213 * 〇 . 重復步驟B，分別於該查找表213中記錄該顯示裝置20 在持續工作時間T分別等於T2、T3、T4……時對應之最佳 公共電壓值V2、V3、V4....... 請參閱圖3,其係圖2所示液晶顯示裝置20之驅動方法 流程圖。該液晶顯示裝置驅動方法包括以下步驟： 步驟S1，提供一包括一公共電極之液晶顯示面板201 ; ® 步驟S2,向該公共電極輸入公共電壓，並每隔一段時間 依據該液晶顯示面板201之持續工作時間調整該公共電壓之 值。 在該液晶顯示裝置20開始工作時，其需要一個起始的 公共電壓。此時，該計時器211發送一起始時間訊號至該微 處理單元212，該微處理單元212從該查找表213中讀取起 始時刻該輸出端215所需要輸出之最佳公共電壓值，並依據 0内部程序將該最佳公共電壓值轉化為調整訊號。該電壓調整 電路214依據該調整訊號產生一起始公共電壓，並由該輸出 端215輸出至該液晶顯示面板201之公共電極。 在該液晶顯示裝置20工作一段時間後，例如持續工作 時間T=10分鐘，該計時器211向該微處理單元212發送時 間訊號，該微處理單元212調用相應程序從該查找表213中 讀取該液晶顯示裝置20持續工作時間Τ=10分鐘所對應之最 佳公共電壓值，並將該最佳公共電壓值轉化為調整訊號以控 制該電壓調整電路214調整輸出之公共電壓，同時，該電壓 13 200941432 調整電路214調整後之公共電壓經該輸出端215輸出至該液 晶顯示面板201，從而校正該液晶顯示面板201之公共電極 之有效公共電壓。 再次經過一段時間後，例如10分鐘，該計時器212再 次發出時間訊號，該微處理單元212從該查找表213中讀取 該液晶顯示裝置20持續工作時間T=20分鐘時所對應之最佳 公共電壓值，由該電壓調整電路214調整並由該輸出端215 輸出至該液晶顯示面板201，從而再次校正該液晶顯示面板 201之公共電極之有效公共電壓。 每隔一段時間，該公共電壓產生電路210重新產生一與 該液晶顯示裝置20持續工作時間Τ相對應之最佳公共電壓 輸出至該液晶顯示面板201，校正該液晶顯示面板201之公 共電極之有效公共電壓。. 相較於先前技術，由於本發明液晶顯示裝置20之公共 電壓產生電路210設置有計時器211、微處理單元212、查 ❹找表213及電壓調整電路214,該微處理單元212每隔一段 時間於該查找表213中讀取與該液晶顯示裝置20持續工作 時間Τ對應之最佳公共電壓值，並控制該電壓調整電路214 產生相應之最佳公共電壓，從而校正該液晶顯示面板201中 公共電極之有效公共電壓，減少該有效公共電壓漂移程度， 從而避免因該有效公共電壓漂移而導致之晝面閃爍、晝面粘 滯等現象，使該液晶顯示裝置20之顯示品質穩定。 相較於先前技術，由於本發明液晶顯示裝置20之驅動 方法包括向該公共電極輸入公共電壓，並每隔一段時間依據 14 200941432 該液晶顯示面板之持續工作時間調整該公共電壓之值，從而 使該液晶顯示面板201内公共電極所具有之有效公共電壓因 各種原因產生之漂移大幅減少，從而較大程度上避免因該有 效公共電壓漂移而導致之晝面閃爍、晝面粘滯等問題，進而 使該液晶顯示裝置20之顯示品質較爲穩定。 請參閱圖4，其係本發明液晶顯示裝置第二實施方式之 電路結構方框示意圖。該液晶顯示裝置30與該液晶顯示裝 置20大體相同，其主要區別在於··該液晶顯示裝置30之驅 ¥動電路302進一步包括一時序控制器330,該時序控制器330 用於提供時鐘訊號，並分別與資料驅動電路320及公共電壓 產生電路310之計時器311電連接。該時鐘訊號係具有固定 周期Ta之方波脈衝。 該計時器311包括一計數器316。該計數器316於該液 晶顯示裝置30開啓時記錄之數值X=0，每當該計時器311 所接收之時鐘訊號由高電平變化為低電平時該計數器316所 φ記錄之數值X加1。每當該計數器316記錄之數值X為一數 值Z之整數倍時，例如Z=10000，該計數器316即向微處理 單元312發出記錄有該數值X訊息之數值訊號。 該微處理單元312首先依據該數值X及該時鐘信號之周 期Ta計算該液晶顯示裝置30之持續工作時間T，T=X*Ta。 其次該處理單元312於查找表313中讀取與該持續工作時間 T相應之最佳公共電壓值，控制電壓調整電路314產生並向 液晶顯示面板301輸出最佳公共電壓。 相較於該液晶顯示裝置20，由於該液晶顯示裝置30包 15 200941432 括一產生時鐘訊號之時序控制器330，該計時器311包括一 • 計數器316，通過該計數器316之計算該時鐘訊號所包含之 • 時鐘周期之數目完成該計時器311之計時，且由於每當該計 數器316記錄之數值X為一數值Z之整數倍時便發出數值訊 號，觸發該微處理單元312讀取對應之最佳公共電壓值，進 而可使該液晶顯示裝置30每隔相同的一段時間校正該公共 電壓。 另外’本發明液晶顯示裝置及其驅動方法並不限於以上 實施方式：如該液晶顯示裝置20之電壓調節電路214還可 以為脈頻調變（Pulse Frequency Modulation，PFM)式開關穩 壓電源電路，同時該調節訊號之頻率由該微處理單元212調 整決定；該計時器211還可以在每次開啓該液晶顯示裝置2〇 時將該持續工作時間清空為零，之後再開始計時。 綜上所述，本發明確已符合發明之要件，爰依法提出專 利申請。惟，以上所述者僅為本發明之較佳實施方式，本發 ❾明之範圍並不以上述實施方式為限，舉凡熟悉本案技藝之人 士杈依本發明之精神所作之等效修飾或變化，皆應涵蓋於、 下申請專利範圍内。 、以 【圖式簡單說明】 圖1係一種先前技術液晶顯示裝置之結構示意圖。 圖2係本發明液晶顯示裝置第一實施方式之電路結構方一 意圖。 锻不 圖3係圖2所示液晶顯示裝置20之驅動方法流程圖。 圖4係本發明液晶顯示裳置第2實施方式之電路結構方樞八 16 200941432 意圖。 【主要元件符號說明】 液晶顯不裝置 20、30 液晶顯不面板 201、301 驅動電路 202、302 公共電壓產生電路 210、310 計時器 211、311 微處理單元 212 '312 查找表 213 '313 電壓調整電路 214、314 輸出端 215 資料驅動電路 220、320 計數器 316 時序控制器 330 〇 17200941432 IX. Description of the Invention: [Technical Field] The present invention relates to a display screen display control system and a control method therefor. [Prior Art] Liquid crystal display devices have been widely used in various information, communication, and consumer electronic products due to their advantages of light weight, small size, and low power consumption. Please refer to FIG. 1, which is a schematic diagram of a structure of a prior art liquid crystal display device. The liquid crystal display device 10 includes a liquid crystal display panel 11. The liquid crystal display panel 11 includes a pixel electrode 111, a common electrode 112, a liquid crystal layer 113, an upper polarizer 114, and a lower polarizer 115. The upper polarizer 114 and the lower polarizer 115 are opposed to each other, and the polarization direction is perpendicular. The pixel electrode 111 is disposed between the upper polarizer 114 and the lower polarizer 115. The common electrode 112 is disposed between the pixel electrode 111 and the lower polarizer 115. The liquid crystal layer 113 is disposed on the pixel electrode 111 and Between the common electrodes 112. The pixel electrode 111 and the common electrode 112 are made of a transparent conductive material such as indium tin oxide, indium zinc oxide or the like. A gray scale voltage is applied to the pixel electrode 111, and a common voltage is applied to the common electrode 112 to form a voltage difference between the pixel electrode 111 and the common electrode 112. The voltage difference controls the deflection of liquid crystal molecules (not shown) in the liquid crystal layer 113 in the form of an electric field, and combines the upper polarizer 114 and the lower polarizer 115 to control the throughput of light from the liquid crystal display panel 11. Achieve the purpose of displaying the face. In order to realize different picture display, it is necessary to change the voltage difference between the pixel electrode 111 and the 200941432 common electrode 112. In the prior art, it is common to apply a different gray scale voltage to the pixel electrode 111 by the driving circuit to provide a constant predetermined common voltage to the common electrode 112. However, generally, during the use of the liquid crystal display device 10, as the turn-on time increases, the temperature of the liquid crystal display panel 11 changes, and a DC electric field or the like is generated inside the liquid crystal display panel 11, and at the same time, The material of the common electrode 112 is mostly a poor conductor, which will cause the actual effective common voltage value on the common electrode 112 to drift relative to the preset common voltage value we need. The phenomenon of the drift of the effective common voltage on the common electrode 112 causes the flickering of the facet and the viscous surface of the facet, thereby deteriorating the display quality of the liquid crystal display device 10. Therefore, the display quality of the liquid crystal display device 10 is unstable. SUMMARY OF THE INVENTION In view of the above, it is necessary to provide a liquid crystal display device having stable display quality. At the same time, it is also necessary to provide a driving method for a liquid crystal display device having stable display quality. A liquid crystal display device comprising a liquid crystal display panel and a common voltage generating circuit for supplying a common voltage to the liquid crystal display panel. The common voltage generating circuit includes a micro processing unit, a timer, a voltage adjusting circuit, and a lookup table. The microprocessor unit is electrically coupled to the timer, the voltage regulation circuit, and the lookup table, respectively. This timer is used to record the continuous operation time of the liquid crystal display device. The lookup table is used to store the best common voltage value for each continuous operating time. The micro processing unit is configured to obtain a corresponding optimal common voltage value in the lookup table according to the duration 9 200941432 working time at intervals, and control the voltage adjusting circuit to generate an optimal common voltage. "" A liquid crystal display device driving method, comprising: providing a liquid crystal display panel including a common electrode; b. inputting a common voltage to the common electrode, and continually depending on the duration of the liquid crystal display panel at intervals The working time adjusts the value of the common voltage. Compared with the prior art, since the common voltage generating circuit of the liquid crystal display device of the present invention is provided with a timer, a micro processing unit, a lookup table and a voltage adjusting circuit, the micro processing single s is read in the lookup table every other time. Taking the corresponding optimal common voltage value, and controlling the voltage adjusting circuit to generate a corresponding optimal common voltage, thereby correcting the effective common voltage of the common electrode in the liquid crystal display panel minus the effective common voltage drift degree, thereby avoiding being effective The phenomenon that the screen voltage is drifted due to the drift of the common hill, and the surface of the screen is stagnate, so that the display quality of the liquid crystal display device is stabilized. Compared with the prior art, due to the driving method of the liquid crystal display device of the present invention, a common voltage is input to the common electrode, and the common voltage is adjusted according to the continuous working time of the liquid crystal such as the panel every other time, thereby continuously correcting the The common electrode in the liquid crystal display panel has an effective common voltage, so that the drift of each of the electrodes is greatly reduced, thereby largely avoiding problems such as the effective surface voltage caused by voltage drift, and then the surface (four). The display quality of the δHai liquid crystal display device is relatively stable. [Embodiment] FIG. 2 is a block diagram showing the circuit configuration of a liquid crystal display device of the present invention. The liquid immersion liquid daily display device 20 includes a liquid crystal display 200941432 panel 201 and a driving circuit 202. The driving circuit 202 includes a common voltage generating circuit 210 for generating a common voltage and a data driving circuit 220 for outputting a gray scale voltage. The liquid crystal display panel 201 is respectively supplied with driving signals such as a common voltage and a gray scale voltage. The common voltage generating circuit 210 includes a timer 211, a micro processing unit 212, a lookup table 213, a voltage adjusting circuit 214, and an output terminal 215. The micro processing unit 212 is electrically connected to the timer 211, the lookup table 213, and the voltage adjustment circuit 214, and the output terminal 215 is electrically connected to the voltage adjustment and control circuit 214 and the liquid crystal display panel 201, respectively. When the liquid crystal display device 20 is turned on, the timer 211 starts counting, and a time signal for recording the continuous operation time T of the liquid crystal display device 20 is issued to the micro processing unit 212 at intervals. When the liquid crystal display device 20 is turned off, the continuous operation time T recorded by the timer 211 is set to zero. The continuous working time T is also the continuous working time of the liquid crystal display panel 201. The micro processing unit 212 has an information processing function, which can determine the time signal sent by the timer 211, and perform corresponding processing according to a preset procedure therein, and then send an adjustment signal to the voltage adjustment circuit 214. The adjustment signal is a pulse square wave whose duty ratio is determined by the adjustment of the microprocessor unit 212. The lookup table 213 records the optimum common voltage value corresponding to the continuous operation time T of the liquid crystal display device 20. The voltage adjustment circuit 214 is a Pulse Width Modulation (PWM) type switching regulator power supply circuit, which generates and adjusts a common voltage according to the adjustment signal sent by the micro processing unit 212, and is buffered by the output terminal 215. The common voltage is then output to the liquid crystal display panel 201. 11 200941432 The optimum common voltage value corresponding to the continuous operation time T of the liquid crystal display device 20 recorded by the lookup table 213 can be obtained when the liquid crystal display device 20 is in the test phase: Step A, recording the liquid crystal display device 20 The optimum common voltage at the time T0=0 is turned on; assuming that the preset common voltage required for the common electrode of the liquid crystal display panel 20 is V, the output of the common voltage generating circuit 210 is adjusted when the liquid crystal display device 20 is turned on. The common voltage value causes the effective common voltage of the common electrode to be V, and the common voltage value outputted by the common voltage generating circuit 210 is V0, and the liquid crystal display device 20 continues to operate for Τ=Τ0. The value V0 is the optimum common voltage value of the liquid crystal display device 20 at the time of the continuous operation time T = T0. The voltage value V0 and the time value TO are recorded in the lookup table 213. Step B, recording an optimum common voltage of the liquid crystal display device 20 after a period of operation; q monitoring the effective common voltage on the common electrode when the liquid crystal display device 20 is operated for a period of time, such as the continuous operation time T=T1 Whether it changes or not, there are two cases at this time: 1. The effective common voltage on the common electrode has not changed. At this time, the time value Τ1 is recorded in the lookup table 213, and the voltage value corresponding to the continuous operation time Τ=Τ1 is recorded as VI, where V1 = V0. 2. The effective common voltage on the common electrode changes. At this time, the output voltage of the common voltage output circuit 210 is adjusted so that the effective common voltage of the common electrode is V. At this time, the output voltage value of the common voltage 210 is VI. 12 200941432 Record the time value T1 and the voltage value VI correspondingly in the lookup table 213 * 〇. Repeat step B, and record the display device 20 in the lookup table 213 for a continuous working time T equal to T2, T3, T4, respectively... The optimum common voltage value V2, V3, V4.... Please refer to FIG. 3, which is a flow chart of the driving method of the liquid crystal display device 20 shown in FIG. The liquid crystal display device driving method includes the following steps: Step S1, providing a liquid crystal display panel 201 including a common electrode; Step S2, inputting a common voltage to the common electrode, and continuing according to the duration of the liquid crystal display panel 201 at intervals The working time adjusts the value of the common voltage. When the liquid crystal display device 20 starts operating, it requires an initial common voltage. At this time, the timer 211 sends a start time signal to the micro processing unit 212, and the micro processing unit 212 reads from the lookup table 213 the optimal common voltage value that the output terminal 215 needs to output at the start time, and The optimum common voltage value is converted into an adjustment signal according to an internal program of 0. The voltage adjusting circuit 214 generates a starting common voltage according to the adjusting signal, and outputs the output terminal 215 to the common electrode of the liquid crystal display panel 201. After the liquid crystal display device 20 is operated for a period of time, for example, for a continuous operation time T=10 minutes, the timer 211 sends a time signal to the micro processing unit 212, and the micro processing unit 212 calls the corresponding program to read from the lookup table 213. The liquid crystal display device 20 continues to operate for an optimum common voltage value corresponding to 工作=10 minutes, and converts the optimal common voltage value into an adjustment signal to control the voltage adjustment circuit 214 to adjust the output common voltage, and the voltage is simultaneously 13 200941432 The adjusted common voltage of the adjustment circuit 214 is output to the liquid crystal display panel 201 via the output terminal 215, thereby correcting the effective common voltage of the common electrode of the liquid crystal display panel 201. After a period of time, for example, 10 minutes, the timer 212 sends a time signal again, and the micro processing unit 212 reads from the lookup table 213 that the liquid crystal display device 20 has the best working time T=20 minutes. The common voltage value is adjusted by the voltage adjustment circuit 214 and outputted to the liquid crystal display panel 201 by the output terminal 215, thereby correcting the effective common voltage of the common electrode of the liquid crystal display panel 201 again. The common voltage generating circuit 210 regenerates an optimum common voltage output corresponding to the continuous operating time Τ of the liquid crystal display device 20 to the liquid crystal display panel 201 at intervals, and corrects the effective electrode of the liquid crystal display panel 201. Common voltage. Compared with the prior art, since the common voltage generating circuit 210 of the liquid crystal display device 20 of the present invention is provided with a timer 211, a micro processing unit 212, a lookup table 213 and a voltage adjusting circuit 214, the micro processing unit 212 is every other segment. Reading the optimum common voltage value corresponding to the continuous operation time 该 of the liquid crystal display device 20 in the lookup table 213, and controlling the voltage adjustment circuit 214 to generate a corresponding optimal common voltage, thereby correcting the liquid crystal display panel 201 The effective common voltage of the common electrode reduces the degree of the effective common voltage drift, thereby avoiding the phenomenon of flickering of the face due to the effective common voltage drift, stagnation of the facet, and the like, so that the display quality of the liquid crystal display device 20 is stabilized. Compared with the prior art, the driving method of the liquid crystal display device 20 of the present invention includes inputting a common voltage to the common electrode, and adjusting the value of the common voltage according to the continuous working time of the liquid crystal display panel 14 200941432 at intervals, thereby The effective common voltage of the common electrode in the liquid crystal display panel 201 is greatly reduced due to various reasons, thereby largely avoiding problems such as flickering of the surface caused by the effective common voltage drift, and stagnation of the surface. The display quality of the liquid crystal display device 20 is relatively stable. Please refer to FIG. 4, which is a block diagram showing the circuit structure of a second embodiment of the liquid crystal display device of the present invention. The liquid crystal display device 30 is substantially the same as the liquid crystal display device 20. The main difference is that the driving circuit 302 of the liquid crystal display device 30 further includes a timing controller 330 for providing a clock signal. And electrically connected to the data driving circuit 320 and the timer 311 of the common voltage generating circuit 310, respectively. The clock signal is a square wave pulse having a fixed period Ta. The timer 311 includes a counter 316. The counter 316 records the value X=0 when the liquid crystal display device 30 is turned on, and the value X recorded by the counter 316 is incremented by one every time the clock signal received by the timer 311 changes from a high level to a low level. Whenever the value X recorded by the counter 316 is an integer multiple of a value Z, e.g., Z = 10000, the counter 316 sends a value signal to the microprocessor unit 312 that records the value X message. The microprocessor unit 312 first calculates the continuous operating time T of the liquid crystal display device 30, T = X * Ta, based on the value X and the period Ta of the clock signal. Next, the processing unit 312 reads the optimum common voltage value corresponding to the continuous operation time T in the lookup table 313, and the control voltage adjustment circuit 314 generates and outputs an optimum common voltage to the liquid crystal display panel 301. Compared with the liquid crystal display device 20, the liquid crystal display device 30 includes a timing controller 330 for generating a clock signal, and the timer 311 includes a counter 316, and the counter 316 calculates the clock signal. The number of clock cycles completes the timing of the timer 311, and since each time the value X recorded by the counter 316 is an integer multiple of a value Z, a numerical signal is issued, triggering the micro processing unit 312 to read the corresponding best. The common voltage value, in turn, allows the liquid crystal display device 30 to correct the common voltage every other same period of time. In addition, the liquid crystal display device of the present invention and the driving method thereof are not limited to the above embodiments: the voltage adjusting circuit 214 of the liquid crystal display device 20 may also be a Pulse Frequency Modulation (PFM) type switching regulator power supply circuit. At the same time, the frequency of the adjustment signal is determined by the adjustment of the micro processing unit 212. The timer 211 can also clear the continuous working time to zero each time the liquid crystal display device 2 is turned on, and then start timing. In summary, the present invention has indeed met the requirements of the invention, and the patent application is filed according to law. However, the above description is only the preferred embodiment of the present invention, and the scope of the present invention is not limited to the above-described embodiments, and those skilled in the art can make equivalent modifications or variations according to the spirit of the present invention. All should be covered by the scope of the patent application. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic structural view of a prior art liquid crystal display device. Fig. 2 is a view showing the circuit configuration of the first embodiment of the liquid crystal display device of the present invention. FIG. 3 is a flow chart showing a driving method of the liquid crystal display device 20 shown in FIG. 2. Fig. 4 is a circuit diagram of a second embodiment of a liquid crystal display according to the present invention. [Description of main component symbols] LCD display device 20, 30 Liquid crystal display panel 201, 301 Drive circuit 202, 302 Common voltage generation circuit 210, 310 Timer 211, 311 Micro processing unit 212 '312 Lookup table 213 '313 Voltage adjustment Circuit 214, 314 output 215 data drive circuit 220, 320 counter 316 timing controller 330 〇 17