200949798 九、發明說明： 【發明所屬之技術領域】 本發明是有關於一種晝素電路，特別是指一種可補償 一薄膜電晶體的臨界電壓漂移之畫素電路。 【先前技術】 參閱圖1’習知之畫素電路1包括一第—電晶體u、 一第二電晶體I2、一電容13，及一有機發光:極體（ ❹ 0LED) 14,其中，該等電晶體11、12丨\型薄膜電晶體 ，每一電晶體具有一第一端、一第二端與〜决定該第一段 與該第二端是否導通之控制端，該OLED 14具有一陽極及 一陰極。該第一電晶體11之第一端、該電容13之一端及 該第二電晶體12之控制端電連接，且該第—電晶體u之 第二端接收一資料電壓VDATA1，該第一電晶體n之控制端 接收一控制訊號Vctl丨’該第二電晶體12之第一端接收一 第一電源電壓VDD1，該第二電晶體12之第二端與該〇led ❹ 14之陽極電連接，該OLED 14與該電容13之另一端連接 至一第二電源電壓VSS1。 該操作方式如下：當該控制訊號VCTL1為高電位時，該 第一電晶體11被導通，因此該資料電壓Vdatai被儲存至該 電容13上，且該第二電晶體12之控制端亦接收到該資料 • 電壓Vdatai ;此時，該第二電晶體12將會產生一驅動電流 - Idrivei流過該OLED 14，使得該OLED 14發光，同時在該 OLED 14上產生—電壓降v〇LED1，該驅動電流IDRWEi大小 的計算方式如下所示： 200949798 ^DRIVEi ~ ^12(^05,12 ~^TH,n) ~~^\2^Vdata\ ~K?L£D1 —^77/,12)...........(尸.1) 其中，該乂!^，12為該第二電晶體12之臨界電壓值。 由上述的電流公式（F.1 )可以觀察到，當該第二電晶 體12的臨界電壓VTH，12發生變異，或是OLED 14因為老化使 得其電壓降V0LED1下降時，都會使得該驅動電流的大小改變 ，因此，該OLED 14的亮度便會發生不穩定的現象。 參閱圖2，另一種採用頂部發光（top emission )架構的 習知畫素電路2包括一第一電晶體21、一第二電晶體22、一 電容23，及一 OLED 24，其中，該等電晶體21、22是P型薄 膜電晶體，每一電晶體具有一第一端、一第二端與一決定該 第一段與該第二端是否導通之控制端，該OLED 24具有一陽 極及一陰極。該第一電晶體21之第一端、該電容23之一端及 該第二電晶體22之控制端電連接，且該第一電晶體21之第二 端接收一資料電壓V DATA2 5 該第一電晶體21之控制端接收一 控制訊號VCTL2，該第二電晶體22之第一端與該OLED 24之 陰極電連接，該OLED 24之陽極接收一第一電源電壓VDD2， 該第二電晶體22之第二端與該電容23之另一端連接至一第二 電源電壓VsS2。 該操作方式如下：當該控制訊號VcTL2為低電位時，該 第一電晶體21被導通，因此該資料電壓VDATA2被儲存至該電 容23上，且該第二電晶體22之控制端亦接收到該資料電壓 VdATA2 > 此時’會產生^一驅動電流Idrive2流過該OLED 24， 使得該OLED 24發光，同時在該OLED 24上產生一電壓降 200949798 V〇LED2 ’因此該第·-•電晶體之第·一端的電歷值為Vdd2_V〇leD2 ’該驅動電流I〇rIVE2大小的計算方式如下所示： (F2) ^DRIVE! = ^^22 (^50,22 ~l ^77/,22 I)2 ~ ~^22^DD2 OLEDI ~ ^〇ΜΓ/ΰ~ i Κΐί,22 ^......... 其中，該VTH,22為該第二電晶體22之臨界電壓值。 由上述的電流公式（F.2)可以觀察到，當該第二電晶 體22的臨界電壓νΤΗ,μ發生變異，或是〇LED 24因為老化使 得其電壓降V〇led2下降時，都會使得該驅動電流的大小改變 ’進而使得該OLED 24的亮度便會發生不穩定的現象。同時 ’當習知之畫素電路2應用於一大尺寸面板上時，隨著訊號 線的拉長，内阻逐漸增加，將使得該電源電壓Vdd2發生衰減 效應，稱之為IR_drop效應，該效應將導致該驅動電流Idrive2 下降，因而使得該大尺寸面板亮度不均勻的情況。 歸納以上結果，該等習知之畫素電路具有以下缺點： 一、 面板亮度不均勻或不穩定： φ 因為一面板長時間使用或是因為製程差異將會造 成該臨界電壓值Vth的變異，將會使得流經該〇led 的驅動電流idrive產生變化，因此該〇LED的發光亮度 將會又到影響，當該面板中的多數畫素電路皆受到該 臨界電壓值vTH變異所影響時，容易使得該面板看起 • 來的亮度不均勻或是發生有時較亮有時較暗等亮度不 穩定的問題產生。 二、 無法適用於大尺寸面板上： 田S知之畫素電路應用於一大尺寸面板上時，隨 7 200949798 著訊號線的拉長，内阻逐漸增加，將使得該電源電壓 Vdd發生衣減效應，稱之為iR_dr〇p效應，該效應將導 致該驅動電流IDRIVE下降，因而使得該大尺寸面板亮度 不均勻的情況。隨著面板的尺寸越來越大，IR-dr〇p效 應會更加明顯。因此，若是應用習知之晝素電路於一 大尺寸面板時，IR-dr〇p效應將會產生相當嚴重的後果200949798 IX. Description of the Invention: [Technical Field] The present invention relates to a halogen circuit, and more particularly to a pixel circuit capable of compensating for a critical voltage drift of a thin film transistor. [Prior Art] Referring to FIG. 1 'the conventional pixel circuit 1 includes a first transistor u, a second transistor I2, a capacitor 13, and an organic light emitting body: ❹ 0 LED 14, wherein a transistor 11, 12 丨 type thin film transistor, each transistor having a first end, a second end and a control terminal for determining whether the first segment and the second terminal are conductive, the OLED 14 having an anode And a cathode. The first end of the first transistor 11, the one end of the capacitor 13 and the control end of the second transistor 12 are electrically connected, and the second end of the first transistor u receives a data voltage VDATA1, the first electric The control terminal of the crystal n receives a control signal Vct1 丨 'the first end of the second transistor 12 receives a first power voltage VDD1, and the second end of the second transistor 12 is electrically connected to the anode of the 〇 led ❹ 14 The OLED 14 and the other end of the capacitor 13 are connected to a second power supply voltage VSS1. The operation mode is as follows: when the control signal VCTL1 is high, the first transistor 11 is turned on, so the data voltage Vdatai is stored on the capacitor 13, and the control terminal of the second transistor 12 is also received. The data • voltage Vdatai; at this time, the second transistor 12 will generate a driving current - Idrivei flows through the OLED 14 to cause the OLED 14 to emit light while generating a voltage drop v 〇 LED1 on the OLED 14 The calculation method of the driving current IDRWEi size is as follows: 200949798 ^DRIVEi ~ ^12(^05,12 ~^TH,n) ~~^\2^Vdata\ ~K?L£D1 —^77/,12). ..... (corpse.1) wherein, 乂!^, 12 is the threshold voltage value of the second transistor 12. It can be observed from the above current formula (F.1) that when the threshold voltage VTH, 12 of the second transistor 12 is mutated, or the OLED 14 is lowered due to aging, the voltage drop V0LED1 is lowered. The size changes, and therefore, the brightness of the OLED 14 is unstable. Referring to FIG. 2, another conventional pixel circuit 2 using a top emission structure includes a first transistor 21, a second transistor 22, a capacitor 23, and an OLED 24, wherein the The crystals 21 and 22 are P-type thin film transistors, each of the transistors has a first end, a second end and a control end for determining whether the first end and the second end are conductive. The OLED 24 has an anode and a cathode. The first end of the first transistor 21, the one end of the capacitor 23 and the control end of the second transistor 22 are electrically connected, and the second end of the first transistor 21 receives a data voltage V DATA2 5 . The control terminal of the transistor 21 receives a control signal VCTL2. The first end of the second transistor 22 is electrically connected to the cathode of the OLED 24. The anode of the OLED 24 receives a first power voltage VDD2. The second transistor 22 The second end and the other end of the capacitor 23 are connected to a second power voltage VsS2. The operation mode is as follows: when the control signal VcTL2 is low, the first transistor 21 is turned on, so the data voltage VDATA2 is stored on the capacitor 23, and the control terminal of the second transistor 22 is also received. The data voltage VdATA2 > will generate a driving current Idrive2 flowing through the OLED 24, so that the OLED 24 emits light, and a voltage drop is generated on the OLED 24 200949798 V〇LED2 'so the first-- The electrical value of the first end of the crystal is Vdd2_V〇leD2 'The calculation of the magnitude of the drive current I〇rIVE2 is as follows: (F2) ^DRIVE! = ^^22 (^50,22 ~l ^77/,22 I) 2 ~ ~^22^DD2 OLEDI ~ ^〇ΜΓ/ΰ~ i Κΐί, 22 ^......... wherein, VTH, 22 is the threshold voltage value of the second transistor 22. It can be observed from the above current formula (F.2) that when the threshold voltage ν ΤΗ of the second transistor 22 is varied, or the 〇 LED 24 is lowered due to aging, the voltage drop V 〇 led2 is lowered. The magnitude of the drive current changes 'and thus the brightness of the OLED 24 will be unstable. At the same time, when the conventional pixel circuit 2 is applied to a large-sized panel, as the signal line is elongated, the internal resistance is gradually increased, which will cause the power supply voltage Vdd2 to attenuate, which is called the IR_drop effect. This causes the drive current Idrive2 to drop, thus making the large-size panel uneven in brightness. In summary of the above results, these conventional pixel circuits have the following disadvantages: 1. The panel brightness is uneven or unstable: φ Because a panel is used for a long time or because the process difference will cause the variation of the threshold voltage value Vth, The driving current idrive flowing through the 〇led changes, so that the illuminating brightness of the 〇LED will be affected again. When most of the pixel circuits in the panel are affected by the threshold voltage value vTH variation, it is easy to make The panel looks like • The brightness is uneven or the brightness is unstable when it is sometimes brighter and sometimes darker. Second, it can not be applied to large-size panels: When the S-known pixel circuit is applied to a large-size panel, with the extension of the signal line of 7 200949798, the internal resistance gradually increases, which will cause the power supply voltage Vdd to have a clothing reduction effect. This is called the iR_dr〇p effect, which will cause the drive current IDRIVE to drop, thus making the large-size panel uneven. As the size of the panel grows larger, the IR-dr〇p effect becomes more pronounced. Therefore, if a conventional singular circuit is applied to a large-sized panel, the IR-dr〇p effect will have considerable consequences.
三、OLED老化效應影響發光效率： 由於材料老化的現象，OLED在長時間操作下，可 能會發生OLED電塵降V〇LED逐漸上升而影響到該驅動電 流Idrwe的大小。因此，若因長時間操作造成〇LED老化 ’進而使得該OLED的發光效率下降，那即便是該驅動 電流IDRIVE符合預期，也無法產生預期的亮度。若是發 生在RGB三色的發光效率下降程度不同，更會發生色偏 的問題。 ❹ 【發明内容】 因此，本發明之目的，即在提供一種晝素電路，包含 :-具有-陽極及-陰極之有機發光二極體，及一驅動電路 。該驅動電路包括一第一電晶H、一第二電晶體、一第三電 晶體、一電容，及一開關；每一電晶體具有一第一端、一第 二端，及-決定該第-端及該第二端是否導通的控制端。其 中’該第-電晶體之第二端與該電容之—端電連接，該第一 電晶體之第-端與該第二電晶體之第一端、該第三電晶體之 第一端，及該有機發光二極體之陰極電連接，該第二電晶體 200949798Third, the aging effect of OLED affects the luminous efficiency: Due to the aging of the material, under the long-term operation of the OLED, the OLED electric dust drop V〇LED may gradually rise and affect the size of the driving current Idrwe. Therefore, if the luminescence efficiency of the OLED is lowered due to long-term operation, the luminous efficiency of the OLED is lowered, and even if the driving current IDRIVE is as expected, the desired luminance cannot be produced. If the luminous efficiency of the three colors of RGB is different, the problem of color shift will occur. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a halogen circuit comprising: - an organic light emitting diode having an anode and a cathode, and a driving circuit. The driving circuit includes a first transistor H, a second transistor, a third transistor, a capacitor, and a switch; each transistor has a first end, a second end, and - determines the first - The terminal and the second terminal are conductive terminals. Wherein the second end of the first transistor is electrically connected to the terminal of the capacitor, the first end of the first transistor and the first end of the second transistor, and the first end of the third transistor, And electrically connecting the cathode of the organic light emitting diode, the second transistor 200949798
，並接受該第一控制訊號的控制， 壓到該第一電晶體之第二端，該有機發光二極體之陽極接收 一第一電源電壓，而該第三 電壓。 ’該開關接收一資料電壓 以決定是否輸出該資料電 電晶體之第二端接收一第二電源 本發明之另一目的在提供一驅動電路，包含：一第 電晶體、一第二電晶體、一筹 ;每一電晶體具有一第一端、 一第二電晶體、一電容，及一開關 端、一第二端，及一決定該第一端 及該第二端是否導通的控制端。其中，該第一電晶體之第二 端與該電容之一端電連接，該第一電晶體之第一端、該第二 電晶體之第一端，及該第三電晶體之第一端電連接，該第二 電晶體之第二端、該電容之另一端，及該第三電晶體之控制 端電連接，該第二電晶體之控制端接收一第一控制訊號，該 第一電晶體之控制端接收一第二控制訊號，該開關接收一資 料電壓，並接受該第一控制訊號的控制，以決定是否輸出該 資料電壓到該第二電晶體之第二端，而該第三電晶體之第二 端接收一第二電源電壓。 本發明之另一目的在提供一畫素電路，包含：一具有 一陽極及一陰極之發光元件，及一驅動電路。該驅動電路包 括一第一電晶體、一第二電晶體、一第三電晶體、一電容， 及一開關，每一電晶體具有一第一端、一第二端，及一決定 該第一端及該第二端是否導通的控制端。其中，該第一電晶 200949798 體之第二端與該電容之一端電連接，該第一電晶體之第一端 與該第二電晶體之第一端、該第三電晶體之第一端，及該發 光元件之陰極電連接，該第二電晶體之第二端、該電容之另 一端，及該第三電晶體之控制端電連接，該第二電晶體之控 制端接收一第一控制訊號，該第一電晶體之控制端接收一第 二控制訊號，該開關接收一資料電壓，並接受該第一控制訊 號的控制，以決定是否輸出該資料電壓到該第一電晶艎之第 一端，該發光元件之陽極接收一第一電源電壓，而該第三電 晶體之第二端接收一第二電源電壓。 【實施方式】 有關本發明之前述及其他技術内容、特點與功效，在 以下配合參考圖式之一個較佳實施例的詳細說明中，將可 清楚的呈現。 參閱圖3，本發明之較佳實施例包含一 OLED 8及一驅 動電路9,該驅動電路9包括一第一電晶體91、一第二電 晶體92、一第三電晶體93、一電容95及一開關9〇，其中 ，在本實施例中該開關90是一第四電晶體94。該第一至該 第四電晶體91〜94是P型薄膜電晶體（TFT)»其中，每一 電晶體91〜94包括一第一端、一第二端及一決定該第一段 與該第二端是否導通之控制端，該0LED 8具有一陽極及一 陰極。 該第一電晶體91之第二端與該第四電晶體94之第一 端、該電容95之一端電連接（以下稱為A點）；該第一電 晶體91之第一端與該第二電晶體92之第一端、該第三電 10 200949798 8之陰極電連接（以下稱為bAnd receiving the control of the first control signal, pressing to the second end of the first transistor, the anode of the organic light emitting diode receiving a first power voltage, and the third voltage. The switch receives a data voltage to determine whether to output the second end of the data transistor to receive a second power supply. Another object of the present invention is to provide a driving circuit comprising: a first transistor, a second transistor, and the like Each of the transistors has a first end, a second transistor, a capacitor, and a switch end, a second end, and a control end that determines whether the first end and the second end are conductive. The second end of the first transistor is electrically connected to one end of the capacitor, the first end of the first transistor, the first end of the second transistor, and the first end of the third transistor are electrically Connecting, the second end of the second transistor, the other end of the capacitor, and the control end of the third transistor are electrically connected, and the control end of the second transistor receives a first control signal, the first transistor The control terminal receives a second control signal, the switch receives a data voltage, and receives control of the first control signal to determine whether to output the data voltage to the second end of the second transistor, and the third power The second end of the crystal receives a second supply voltage. Another object of the present invention is to provide a pixel circuit comprising: a light-emitting element having an anode and a cathode, and a driving circuit. The driving circuit includes a first transistor, a second transistor, a third transistor, a capacitor, and a switch, each transistor having a first end, a second end, and a first The terminal and the second end are conductive terminals. The second end of the body of the first transistor 200949798 is electrically connected to one end of the capacitor, the first end of the first transistor and the first end of the second transistor, and the first end of the third transistor And electrically connecting the cathode of the light-emitting element, the second end of the second transistor, the other end of the capacitor, and the control end of the third transistor are electrically connected, and the control end of the second transistor receives a first a control signal, the control end of the first transistor receives a second control signal, the switch receives a data voltage, and receives control of the first control signal to determine whether to output the data voltage to the first transistor The first end, the anode of the light emitting element receives a first power voltage, and the second end of the third transistor receives a second power voltage. The above and other technical contents, features, and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments. Referring to FIG. 3, a preferred embodiment of the present invention includes an OLED 8 and a driving circuit 9. The driving circuit 9 includes a first transistor 91, a second transistor 92, a third transistor 93, and a capacitor 95. And a switch 9A, wherein the switch 90 is a fourth transistor 94 in this embodiment. The first to fourth transistors 91 to 94 are P-type thin film transistors (TFTs). Each of the transistors 91 to 94 includes a first end, a second end, and a first segment and the Whether the second end is conductive or not, the OLED 8 has an anode and a cathode. The second end of the first transistor 91 is electrically connected to the first end of the fourth transistor 94 and one end of the capacitor 95 (hereinafter referred to as point A); the first end of the first transistor 91 and the first end The first end of the second transistor 92, the third electric 10 200949798 8 cathode electrical connection (hereinafter referred to as b
晶體93之第一端及該〇Led 點）；該第二電晶體92之第二 該第三電晶體93之控制迪带 該較佳實施例之時序圖如圖4所示，可以分為二個階 段： χ· 資料輸入階段： 聯合參閱圖4與圖5,該第一電源電壓Vdd將會由一高 電位降至一低電位，而該第二電源電壓Vss將會由一低電位 vssl ( -6伏特）至一高電位Vssh ( 〇伏特），因此該 OLED 8將會不導通。該第一控制訊號Vseli設定為低電位 〇 ’該第二控制訊號VSEL2設定為高電位，因此，該第二及第 四電晶體92、94將會被導通’而該第一電晶體91將會被 關閉’該資料電壓VDATA將會被傳送至A點，由於該第二 電晶體92之第一及第二端分別電連接於該第三電晶體％ 之控制端與第—端，且該第二電晶體92處於導通狀態，因 此’該第三電晶體93在控制端將會產生一臨界電壓Vth>93 • ’且B點及C點電壓亦為該臨界電壓值vTH，93 ;而該電容 之跨壓 Vc 為 VTh，93 — VdaTA 0 u·發光階段： 11 200949798 第閱圖4與圖6,在該f料輸人階段結束之後，該 二電为^ I將會由一低電位升至-高電位，而該第 、=壓〜將會由一高電位Vssh(〇伏特）至一低電位 電壓值「伏特）’因此，該0LED 8將會被導通，而B點的 v〇D、V亦為”亥第二電晶體93第-端之電壓it vs，93)為 ❹ ❹ 。該笛0LED其中該V0LED為0LED 8導通時的電壓降 號^ —控制訊號VSEL>由低電位至高電位’該第二控制訊 被EL2由问電位至低電位，因此，該第一電晶體將會 通，A點電壓值（亦為該第三電晶體93第一端之電壓 j畜- 、 S，93)為VDD~V〇LED，此時該電容95的端電壓也會隨 之改變，而該第二及第四電晶體92、94會被關閉，因此， C Η： φ X 電壓值（亦為該第三電晶體93控制端之電壓值vG>93 ) 為 V ， .、' TH，93 —Vdata+Vdd—V0LED ;由於該 OLED 8 被導通 ，因此，會產生一由該OLED 8流至該第三電晶體93第一 端之驅動電流IDRIVE為： 1 DRIVE = 2^93 ^G,93-| ^77/,93 I)2 =2 ^3(^,93 - ^,93- I ^W,93 I)' =2 ^93(^)0 - VOLED ~ (^m,93 ~ ^data + VDD ~ ^〇LEd)~ I ^77/,93 I)2 2 K^^Vdd ~ ^0LED+ I ^77/,93 I DATA ~ ^DD + ^〇LED~ I ^TH,93 I)2 » ... )^ < 0 2 ^•93data).......................................................................(尺3) 根據上述的電流公式（F.3 )可以知道，流經〇LED 8 的驅動電流Idrive與該等第一、第二電源電壓VDD、VSS、 12 200949798 該第三電晶體93的臨界電壓The first end of the crystal 93 and the 〇Led point); the control strip of the second transistor 93 of the second transistor 92; the timing diagram of the preferred embodiment is as shown in FIG. Stages: χ· Data input stage: Referring to FIG. 4 and FIG. 5 together, the first power supply voltage Vdd will be reduced from a high potential to a low potential, and the second power supply voltage Vss will be controlled by a low potential vssl ( -6 volts to a high potential Vssh (〇V), so the OLED 8 will not conduct. The first control signal Vseli is set to a low potential 〇 'the second control signal VSEL2 is set to a high potential, therefore, the second and fourth transistors 92, 94 will be turned on' and the first transistor 91 will Turned off, the data voltage VDATA will be transmitted to point A, since the first and second ends of the second transistor 92 are electrically connected to the control terminal and the first terminal of the third transistor, respectively, and the first The second transistor 92 is in an on state, so that the third transistor 93 will generate a threshold voltage Vth > 93 • ' at the control terminal and the voltage at point B and point C is also the threshold voltage value vTH, 93; and the capacitor The cross-over voltage Vc is VTh, 93 - VdaTA 0 u· illuminating phase: 11 200949798. Referring to FIG. 4 and FIG. 6, after the end of the input phase of the f-material, the second electric power will rise from a low potential to - high potential, and the first, = pressure ~ will be from a high potential Vssh (〇 volts) to a low potential voltage value "volts". Therefore, the 0LED 8 will be turned on, and the V point D at point B, V is also "the voltage of the second end of the second transistor 93, it is vs. 93" is ❹ ❹. The horn 0 LED, wherein the V0LED is a voltage drop number when the OLED 8 is turned on, the control signal VSEL> is from a low potential to a high potential, and the second control signal is caused by the EL2 from the potential to the low potential. Therefore, the first transistor will Pass, the voltage value of point A (also the voltage of the first end of the third transistor 93, j-, S, 93) is VDD~V〇LED, and the terminal voltage of the capacitor 95 will change accordingly. The second and fourth transistors 92, 94 are turned off. Therefore, the voltage value of C Η: φ X (also the voltage value of the control terminal of the third transistor 93 vG > 93) is V, ., 'TH, 93—Vdata+Vdd—V0LED; since the OLED 8 is turned on, a driving current IDRIVE flowing from the OLED 8 to the first end of the third transistor 93 is generated: 1 DRIVE = 2^93 ^G, 93-| ^77/,93 I)2 =2 ^3(^,93 - ^,93- I ^W,93 I)' =2 ^93(^)0 - VOLED ~ (^m,93 ~ ^ Data + VDD ~ ^〇LEd)~ I ^77/,93 I)2 2 K^^Vdd ~ ^0LED+ I ^77/,93 I DATA ~ ^DD + ^〇LED~ I ^TH,93 I)2 » ... )^ < 0 2 ^•93data).................................... ...................................(尺3) According to the above current formula (F.3) It can be known that the driving current Idrive flowing through the 〇LED 8 and the threshold voltages of the first and second power supply voltages VDD, VSS, 12 200949798 of the third transistor 93
VtH，93 ’ 及OLED 8的電壓降 VOLED無關。因此，在發光階段時，流經OLED 8的驅動電 流 Idrive 僅僅由該資料電壓 Vdata大小來決定。 值得注意的是，本實施例除了用於驅動該OLED 8之外 ，也可以用於驅動其他受電流驅動的發光元件，例如：發 光二極體（LED)，且該等電晶體91〜94除了是P型TFT 之外，也可以是P型金屬氧化物半導體（PMOS )。The voltage drop of VtH, 93 ’ and OLED 8 has nothing to do with VOLED. Therefore, in the illuminating phase, the driving current Idrive flowing through the OLED 8 is determined only by the magnitude of the data voltage Vdata. It should be noted that, in addition to driving the OLED 8, the embodiment can also be used to drive other current-driven light-emitting components, such as light-emitting diodes (LEDs), and the transistors 91-94 except In addition to the P-type TFT, it may be a P-type metal oxide semiconductor (PMOS).
由於本發明之驅動電流I DRIVE 僅與該資料電壓 Vdata 大 小有關，因此，相較於習知之設計具有下列優點： 一、 具有補償該臨界電壓Vth, 93變異的特性： 當一面板在長時間操作下或是因為製程上的差異 ，所產生的臨界電壓 Vth,93 差異，可能會影響OLED上 的驅動電流IDRIVE大小，進而造成一面板上發光亮度的 不均勻或是不穩定的情形，然而利用本發明晝素電路 之面板，可以避免因臨界電壓VTH的變異所造成的亮 度問題。 二、 能應用於大尺寸面板上： 由於本發明之畫素電路的驅動電流IDRIVE與第一 、第二電源電壓VDD、Vss無關，因此，當應用於大尺 寸面板時，可能因為訊號線過長所引起的IR-drop效應 ，將不會影響該驅動電流Idrive，因此’不會對OLED 8的發光亮度造成影響。 三、 不會影響OLED的發光效率： 由於本發明之畫素電路的驅動電流I DRIVE與該 13 200949798 邱的電壓降v〇led無關，因此，當一使用本晝素電 路為光源之面板，縱使内部發生有OLED 8因為長久使 用而產生材料老化，進而使得OLED 8的電壓降上升時 ’也不會使得該驅動電流Idrive產生改變，* 〇led 8 的發光效率得以保持穩定，因此，當本發明之畫素電 路應用於RGB顯示裝置時，可以避免因為RGB三色 LED因為出現發光效率不一致而導致色偏的問題發生 〇 綜上所述，本發明之實施例可以確保畫素電路中該驅 動電流將不會受到Vth變異、IR-drop效應及OLED老化等 因素而改變，因此確實能達成本發明之目的。 惟以上所述者，僅為本發明之較佳實施例而已，當不 能以此限定本發明實施之範圍，即大凡依本發明申請專利 範圍及發明說明内容所作之簡單的等效變化與修飾，皆仍 屬本發明專利涵蓋之範圍内。 【圖式簡單說明】 圖1是一種習知之晝素電路之電路示意圖； 圖2是另一種習知之電路之電路示意圖； 圖3是本發明之較佳實施例之電路示意圖； 圖4是該較佳實施例之時序圖； 圖5是該較佳實施例之資料輸入階段之等效電路示意 圖；及 圖6是該較佳實施例之發光階段之等效電路示意圖。 14 200949798 【主要元件符號說明】 8…… ••…有機發光二極體 93 •…第三電晶體 9…… •…驅動電路 94·.·· •’第四電日日體 91 ··... •…第一電晶體 95··.·· …·電容 92.，·· …·第二電晶體 90 •… …·開關Since the driving current I DRIVE of the present invention is only related to the magnitude of the data voltage Vdata, it has the following advantages compared with the conventional design: 1. It has the characteristics of compensating for the threshold voltage Vth, 93 variation: when a panel is operated for a long time The difference between the threshold voltages Vth and 93 generated by the process may affect the driving current IDRIVE on the OLED, which may cause unevenness or instability of the luminance on one side of the board. The invention of the panel of the pixel circuit can avoid the brightness problem caused by the variation of the threshold voltage VTH. Second, it can be applied to a large-sized panel: Since the driving current IDRIVE of the pixel circuit of the present invention is independent of the first and second power supply voltages VDD, Vss, when applied to a large-sized panel, the signal line may be too long. The resulting IR-drop effect will not affect the drive current Idrive, so 'will not affect the luminosity of the OLED 8. Third, it does not affect the luminous efficiency of the OLED: Since the driving current I DRIVE of the pixel circuit of the present invention is independent of the voltage drop v〇led of the 13 200949798, when using a pixel circuit as a light source panel, even Internally, the OLED 8 is aging due to long-term use, and thus the voltage drop of the OLED 8 rises, 'the drive current Idrive does not change, and the luminous efficiency of the 〇led 8 is kept stable. Therefore, when the present invention is When the pixel circuit is applied to the RGB display device, the problem of color shift due to the inconsistent luminous efficiency of the RGB three-color LED can be avoided. In summary, the embodiment of the present invention can ensure the driving current in the pixel circuit. It will not be changed by factors such as Vth variation, IR-drop effect, and OLED aging, and thus the object of the present invention can be achieved. The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic circuit diagram of a conventional circuit; FIG. 2 is a circuit diagram of another conventional circuit; FIG. 3 is a schematic circuit diagram of a preferred embodiment of the present invention; FIG. 5 is an equivalent circuit diagram of the data input stage of the preferred embodiment; and FIG. 6 is an equivalent circuit diagram of the illumination stage of the preferred embodiment. 14 200949798 [Explanation of main component symbols] 8... ••...Organic LEDs 93 •...third transistor 9... •...drive circuit 94·.·· • 'fourth solar day 91 ··. .. •...first transistor 95·······capacitor 92.,····second transistor 90 •...
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