201121354 六、發明說明： 【發明所屬之技術領域】 本發明係關於一種有機發光二極體顯示器，尤指一種補償電晶體的臨 界電壓差異的有機發光二極體顯示器。 【先前技術】 功能先進的顯示器已漸成為現今消費電子產品的重要特色，其中有機 發光二極體(Organic Light Emitting Diodes，OLED)係一種光電子轉換裝置， 因具有無視角限制、製造成本低及高輝度等優點而越來越受到業界關注。 有機發光二極體顯示器依據驅動方式不同可分為主動矩陣式有機發光二極 體顯示器(Active Matrix Organic Light Emitting Diodes，AMOLED)與被動矩 陣(Passive Matrix)式有機發光二極體顯示器。 請參閱第1圖，第1圖係繪示先前技術之有機發光二極體28以及其驅 動電路20之電路圖。傳統的主動式矩陣式有機發光二極體顯示器的驅動電 路20包含電晶體22、24以及電容26。電晶體22作為開關電晶體是用來負 責資料寫入儲存開關，而電晶體24則作為驅動電晶體負責控制電流大小。 一般狀況下’電晶體24會持續操作在飽和區，因此會受到臨界電壓(thresh〇id voltage) Vth影響。而臨界電壓Vth則會因製程或結構的不同而有所差異， 或者是因為長時間因電容26的加壓造成電晶體24的臨界電壓上升。又由 於電晶體24的輸出電流Ids係等於(1/2) X K X (Vgs-Vth)2，其中κ係一常數 且Vgs表示電晶體閘-源極跨壓。因為臨界電壓Vth的變化會直接影響到電 晶體24的輪出電流Ids，造成有機發光二極體28的亮度因輪出電流Ms差 201121354 異而產生不均勻之現象。為了使臨界電壓的變化影響減到最低目前大多 數的做賴是· _畫素電路設相達_償糊邱些内部畫素電 路通常都需使_ 5個甚至更多的電晶體，但相對㈣雜制上就較為複 雜。 【發明内容】 有鑑於此，本發明係有關於一種驅動一有機發光二極體的驅動電路， 驅動電路會量測電壓或電流’並儲存至記憶體内，經由所儲存之資訊對每 -晝素做修正’藉此補償畫素巾的鶴電晶_製料老化縣造成的臨 界電壓偏移，改善亮度不均勻之現象。 本發明係有關於-麵示器，其包含_驅動器、源極驅動器、間極 驅動器和複數個畫素。侧極驅動器用來產生—_訊號。該源極驅動器 用來產生-資料電壓。每一畫素包含有機發光二極體、第一電晶體、第二 電晶體、第三電晶體、第四電晶體以及電容。第一電晶體的閘極输於該 鲁掃8¾訊號’其滅祕於該資料電壓。第二電晶體_極祕於該第一電 晶體之源極，其源極輕接於該有機發光二極體。第三電晶體的閉極耗接於 -控制訊號，歧純接於—細電壓電路，其雜祕於該第二電晶體 之没極。第四電晶體的閘極耦接於該控制訊號，其没極耦接於一電源電壓， 其源極耦接於該第二電晶體之汲極。該電容的兩端分別耦接於該第二電晶 體之沒極和源極。 本發明係有關於一種驅動一有機發光二極體的驅動電路，其包含第一電 晶體、第二電晶體、第三電晶體、第四電晶體以及電容。第—電晶體的問 201121354 極輕接於該掃gg訊號，其汲極祕於該資料賴^第二電晶義閘極輕接 於該第-電晶體之雜’其祕耦接於該有機發光二極體。第三電晶體的 閘極輕接於-控制訊號’其汲極輕接於—偏電壓電路，其祕麵接於該 第二電晶體之錄。第四電晶體的_耦接於該控制訊號，其汲極叙接於 電源電壓’其源極耗接於該第二電晶體之没極。該電容的兩端分別搞接 於該第二電晶體之汲極和源極。 根據本發明-實施例所例示之㈣電路在_模式下侧電晶體的臨 界電壓值’並將之儲存於記憶體，並在顯示模式下，驅動有機發光二極體 依據資料龍發出光線。但是資料電壓會根據記顏所齡_界電餅 適度的補償，所以每-個畫素所接收資料電慶都是考量每一畫素内的電晶 體的臨界電壓後的㈣電壓，故可以避免電晶體的臨界電壓因為因製程或 老化現象造成的臨界電壓偏移，因而改善亮度不均勻的問題。 為讓本發明之上述内容能更明顯紐，下文特舉較佳實施例，並配合 所附圖式，作詳細說明如下： 實施方式】 請參照第2圖以及第3圖，第2圖係本發明之有機發光二極體顯示器· 之不意圖’第3 ®係本發明之驅動電路㈣及其驅動之有機舰二極體％ 之示意圖，光二極麵示器,。包含顯示面板12、閉極驅動器㈣e 如ver)14、源極驅動器(s。麗“)16、_魏電路⑼控制㈣以及 記憶體7G。顯示面板12包含細啦18，每—畫㈣包含—驅動電路 201121354BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting diode display, and more particularly to an organic light emitting diode display that compensates for a difference in critical voltage of a transistor. [Prior Art] Advanced display has become an important feature of today's consumer electronics products. Organic Light Emitting Diodes (OLED) is a kind of optoelectronic conversion device with low viewing angle, low manufacturing cost and high cost. The advantages such as brightness are getting more and more attention from the industry. The organic light emitting diode display can be classified into an active matrix organic light emitting diode (AMOLED) and a passive matrix organic light emitting diode display depending on the driving method. Referring to Fig. 1, there is shown a circuit diagram of a prior art organic light emitting diode 28 and its driving circuit 20. The drive circuit 20 of a conventional active matrix organic light emitting diode display includes transistors 22, 24 and a capacitor 26. The transistor 22 is used as a switching transistor for the data to be written to the storage switch, and the transistor 24 is used as the driving transistor for controlling the magnitude of the current. Under normal conditions, the transistor 24 will continue to operate in the saturation region and will therefore be affected by the threshold voltage (thresh〇id voltage) Vth. The threshold voltage Vth may vary depending on the process or structure, or because the threshold voltage of the transistor 24 rises due to the pressurization of the capacitor 26 for a long time. Further, the output current Ids of the transistor 24 is equal to (1/2) X K X (Vgs - Vth) 2, where κ is a constant and Vgs represents the gate-source voltage across the gate. Since the change of the threshold voltage Vth directly affects the wheel current Ids of the transistor 24, the brightness of the organic light-emitting diode 28 is uneven due to the difference in the round current Ms 201121354. In order to minimize the impact of the change in the threshold voltage, most of the current work is done. _ The pixel circuit is set up to _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ (4) Miscellaneous is more complicated. SUMMARY OF THE INVENTION In view of the above, the present invention relates to a driving circuit for driving an organic light emitting diode, and the driving circuit measures voltage or current 'and stores it in a memory, and stores information through each of the data. The correction is made to compensate for the critical voltage shift caused by the aging of the painter's 电 巾, which improves the brightness unevenness. The present invention is directed to a facet that includes a _driver, a source driver, an interpole driver, and a plurality of pixels. The side pole driver is used to generate the -_ signal. This source driver is used to generate the -data voltage. Each pixel includes an organic light emitting diode, a first transistor, a second transistor, a third transistor, a fourth transistor, and a capacitor. The gate of the first transistor is output to the 扫 83 83⁄4 signal ’ which is secretive to the data voltage. The second transistor is extremely secreted from the source of the first transistor, and its source is lightly connected to the organic light-emitting diode. The closed end of the third transistor is depleted by the - control signal, which is purely connected to the fine voltage circuit, which is secreted by the second pole of the second transistor. The gate of the fourth transistor is coupled to the control signal, the pole is coupled to a power supply voltage, and the source is coupled to the drain of the second transistor. The two ends of the capacitor are respectively coupled to the non-polar and source of the second electro-optic body. The present invention relates to a driving circuit for driving an organic light emitting diode comprising a first transistor, a second transistor, a third transistor, a fourth transistor, and a capacitor. The first-transistor's question 201121354 is extremely lightly connected to the sweep gg signal, and its sputum is secretive to the data. The second electric crystal gate is lightly connected to the first-electrode crystal. The secret coupling is connected to the organic light. Diode. The gate of the third transistor is lightly connected to the - control signal, and its drain is connected to the bias voltage circuit, and the secret surface is connected to the second transistor. The fourth transistor is coupled to the control signal, and its drain is connected to the power supply voltage, and its source is connected to the second transistor. The two ends of the capacitor are respectively connected to the drain and the source of the second transistor. According to the fourth embodiment of the present invention, the critical voltage value of the side transistor in the _ mode is stored in the memory, and in the display mode, the organic light emitting diode is driven to emit light according to the data dragon. However, the data voltage will be moderately compensated according to the age of the film, so the data received by each pixel is the (four) voltage after considering the threshold voltage of the crystal in each pixel, so it can be avoided. The critical voltage of the transistor is a problem of uneven brightness due to a critical voltage shift due to a process or aging phenomenon. In order to make the above description of the present invention more obvious, the following description of the preferred embodiments will be described in detail below with reference to the accompanying drawings: Embodiments Referring to FIG. 2 and FIG. 3, FIG. 2 is a diagram The invention relates to an organic light-emitting diode display. The third embodiment is a schematic diagram of a driving circuit (four) of the present invention and an organic ship diode of the same, and a photodiode. The display panel 12, the closed-circuit driver (4) e such as ver) 14, the source driver (s. 丽") 16, the _Wei circuit (9) control (4), and the memory 7G. The display panel 12 includes a thin 18, each - (four) contains - Drive circuit 201121354
4〇和-有機發光二極體50。驅動電路40包含第一電晶㈣、第二電晶體 T2、第三電晶體T3、第四電晶體丁4以及電容第—電晶體们的閉_ 接於閘極驅動H Μ以接收_職〇„，其汲極鱗贿、極__以接 收資料電壓V蠢。第二電晶體T2的__於第—電晶體τι之源極，其 源極雛於有機發光二極體50。第三電晶體T3的閘極输於控制器6〇所 發送之控制訊號Gcomp，其汲極耦接於偵測電壓電路8〇以接收侧電壓 Vctet，«_接於第二電晶體T2之錄1四電晶體τ4 _極減於 控制訊號Gcomp ’其没極搞接於電源電壓伽，其源極輕接於第二電晶體 T2之汲極。電容C的兩端分別耦接於第二電晶體丁2之汲極和源極。 請-併參閱第4圖’第4圖係第3圖之驅動電路4()所接收之各個訊號 於_模式下的時序圖。驅動電路4G的操作分為兩麵式，—種是侧模 弋另種疋顯示模式。在偵測模式下，驅動電路4〇會谓測電晶體丁2的 臨界電Μ，並將侧後的臨界電魏存至域體7G巾H齡模式下， 驅動電路4〇會驅動有機發光二極體5〇，使有機發光二極體％依據資料電 壓VDArA發出光線。但是資料電屋v舰會根據記憶體％所儲存的臨界電 壓作適度的補償’所以每—個晝素所接收資料電M v_都是考量每一 畫素18内的電晶體T2 _界電壓Vth後的資料電麼。為了可以正確 的谓測電晶體T2的臨界電壓Vth，在細模式下，在時點u到句第一階 )的期門電阳體T4會因為控制訊號Gcomp啟動而導通，又因為電晶體 τι處於低電壓準位，所以電容c會繼存電位提升至獅電壓。在 時點t2到t3(第二階段)的綱，則將電容C放電直到電晶體T2關閉，此時， 電今c儲存的電位恰好是v^^+vth。在時點〇之後(第三階段），電晶體 201121354 ΤΙ、T4因掃瞄訊號Gn處於高電壓準位且控制訊號Gcomp處於低電壓準仅 而不導通，但電晶體T3卻開啟導通，使得偵測電壓電路80可依據偵測電 壓VDetect偵測電容C儲存的電位vDArA+Vth並儲存至記憶體70内。 到了顯示模式時，控制器60產生的控制訊號Gcomp是處於低電壓率 位，電晶體T3是關閉不導通。同時閘極驅動器14每隔一固定間隔輸出耨 描訊號〇„使得每一列畫素18的電晶體T1依序開啟，同時源極驅動器 會根據記憶體70所紀錄的電位VDATA+Vth計算產生對應的資料電壓4 〇 and - organic light-emitting diode 50. The driving circuit 40 includes a first electro-crystal (4), a second transistor T2, a third transistor T3, a fourth transistor D4, and a capacitor----the transistor is closed to the gate driver H Μ to receive the _ occupation „, its bungee bribes, poles __ to receive the data voltage V stupid. The second transistor T2 __ at the source of the first transistor τι, the source is nested in the organic light-emitting diode 50. Third The gate of the transistor T3 is sent to the control signal Gcomp sent by the controller 6〇, and the drain is coupled to the detection voltage circuit 8 to receive the side voltage Vctet, and the «_ is connected to the second transistor T2. The transistor τ4 _ is substantially reduced by the control signal Gcomp 'which is not connected to the power supply voltage gamma, and its source is lightly connected to the drain of the second transistor T2. The two ends of the capacitor C are respectively coupled to the second transistor 2's drain and source. Please refer to the timing diagram of each signal received in the _ mode of the drive circuit 4() in Fig. 4, Fig. 4, Fig. 4. The operation of the drive circuit 4G is divided into two. Face type, the type is the side mode 弋 another kind of display mode. In the detection mode, the drive circuit 4〇 will be called the critical electric 测 of the transistor D, and will be behind the side In the H-age mode of the 7G towel of the domain of Wei Cun to the domain, the drive circuit 4〇 will drive the organic light-emitting diode 5〇, so that the organic light-emitting diode emits light according to the data voltage VDArA. The threshold voltage stored in the memory % is moderately compensated' so that the data M v_ received by each pixel is the data after considering the transistor T2 _ boundary voltage Vth in each pixel 18. It can correctly measure the threshold voltage Vth of the transistor T2, and in the fine mode, the gate electrode T4 at the time point u to the first step of the sentence is turned on because the control signal Gcomp is activated, and because the transistor τι is at a low level. The voltage level, so the capacitance c will increase the potential to the lion voltage. At the time point t2 to t3 (the second stage), the capacitor C is discharged until the transistor T2 is turned off. At this time, the potential stored by the current c is just right. It is v^^+vth. After the time point 第三 (the third stage), the transistors 201121354 ΤΙ, T4 are at the high voltage level because the scan signal Gn is at the high voltage level and the control signal Gcomp is at the low voltage level and is not turned on, but the transistor T3 Turning on the turn-on, so that the detection voltage circuit 80 can According to the detection voltage VDetect, the potential vDArA+Vth stored in the capacitor C is detected and stored in the memory 70. When the display mode is reached, the control signal Gcomp generated by the controller 60 is at a low voltage rate, and the transistor T3 is turned off. At the same time, the gate driver 14 outputs the scanning signal 每隔 every other fixed interval so that the transistor T1 of each column of pixels 18 is sequentially turned on, and the source driver calculates the corresponding voltage VDATA+Vth recorded by the memory 70. Data voltage
Ydata ’再將資料電壓經由電晶體Ή傳送至電晶體T2。因為電晶體 T2的輸出電流1ds等於(1/2) X K X (Vgs-Vth)2，其中K係一常數且Vgs表示 電晶體T2的閘-源極跨壓’所以電晶體T2的輸出電流地大致等於⑽^ & x (YoAiA-VSS-Vth)2。也就是說，考慮電晶體丁2的臨界電壓νώ後調整的Ydata' then transfers the data voltage to the transistor T2 via the transistor. Since the output current 1ds of the transistor T2 is equal to (1/2) XKX (Vgs - Vth) 2, where K is a constant and Vgs represents the gate-source voltage across the transistor T2, the output current of the transistor T2 is approximately Equal to (10)^ & x (YoAiA-VSS-Vth)2. In other words, consider the critical voltage νώ of the transistor D 2
資料電壓ΥοΛΓΑ可以使得電晶體T2的輸出電流Ids大致等於(1/2) X κ X (Vdata)2。此時，在顯示模式下，電晶體Τ2的臨界電壓Vth幾乎不會影響 輸出電流Ids的變化，所以有機發光二極體5〇可依據流經的輸出電流工如 發出不同亮度的光線。請注意，因為記憶體70會儲存每_個畫素18内的 電晶體T2的臨界電壓Vth和資料電壓Vdafa的變化，所以源極驅動器 最後輪出的補償後資料電壓再輸入對應的晝素18後，個別電晶體乃 的臨界電壓Vth的差異會被抵銷，所以最終有機發光二極體5G所發出的光 線和灰階只與縣資料電壓Vdaia—致，故傳_示面板U顯示亮度不均 勻的問題可以獲得改善。 201121354 雖然本發明已用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内，當可作各種之更動與 修改，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為準。 【圖式簡單說明】 第1圖係繪示先前技術之有機發光二極體以及其驅動電路之電路圖。 第2圖係本發明之有機發光二極體顯示器之示意圖。The data voltage ΥοΛΓΑ can make the output current Ids of the transistor T2 approximately equal to (1/2) X κ X (Vdata) 2 . At this time, in the display mode, the threshold voltage Vth of the transistor 几乎2 hardly affects the change of the output current Ids, so the organic light-emitting diode 5 工 can emit light of different brightness depending on the output current flowing through. Please note that since the memory 70 stores the change of the threshold voltage Vth and the data voltage Vdafa of the transistor T2 in each pixel 18, the compensated data voltage of the last turn of the source driver is input to the corresponding pixel 18 again. After that, the difference of the threshold voltage Vth of the individual transistors will be offset, so the light and gray scale emitted by the organic light-emitting diode 5G are only related to the county data voltage Vdaia, so the display panel U shows the brightness is not Uniform problems can be improved. The present invention has been described above by way of a preferred embodiment, and is not intended to limit the invention, and it is intended that various changes and modifications may be made without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a circuit diagram showing a prior art organic light emitting diode and its driving circuit. 2 is a schematic view of an organic light emitting diode display of the present invention.
第3圖係本發明之驅動電路以及其驅動之有機發光二極體之示意圖。 第4圖係第3圖之驅動電路所接收之各個訊號於偵測模式下的時序圖。 【主要元件符號說明】 10 有機發光二極體顯示器 26 電容 12 顯示面板 14 閘極驅動器 16 源極驅動器 18 畫素 20 驅動電路 22、24 電晶體 40 驅動電路 50 有機發光二極體 60 控制器 70 記憶體 80 偵測電壓電路 T1-T4 電晶體 C 電容 Vdata 資料電壓 VDetect 偵測電壓 Gcomp 控制訊號 Gn 掃瞄訊號 VDD、VSS 電源電壓Figure 3 is a schematic diagram of the driving circuit of the present invention and the organic light-emitting diodes driven thereby. Fig. 4 is a timing chart of the respective signals received by the driving circuit of Fig. 3 in the detection mode. [Main component symbol description] 10 Organic light-emitting diode display 26 Capacitor 12 Display panel 14 Gate driver 16 Source driver 18 Pixel 20 Drive circuit 22, 24 Transistor 40 Drive circuit 50 Organic light-emitting diode 60 Controller 70 Memory 80 Detection voltage circuit T1-T4 Transistor C Capacitor Vdata Data voltage VDetect Detection voltage Gcomp Control signal Gn Scan signal VDD, VSS Supply voltage