JP2002514320A - Active matrix light emitting diode pixel structure and method - Google Patents

Abstract

Abstract: Disclosed are LED pixel structures (200, 300, 400, 600, 700) that reduce current non-uniformity and threshold voltage variation of a pixel structure "drive transistor". The LED pixel structure incorporates a current source to load data into the pixel through data lines. Instead, the auto-zero voltage is determined prior to loading the drive transistor data.

Description

DETAILED DESCRIPTION OF THE INVENTION         Active matrix light emitting diode pixel structure and method   This application claims the benefit of US Provisional Application No. 60 / 044,174, filed April 23, 1997. Claim profit. The contents of which are incorporated herein.   This invention was made with U.S. Government support under contract number F33615-96-2-1944. . The United States Government has certain rights in the invention.   The present invention relates to an active matrix light emitting diode pixel structure. Change More specifically, the present invention relates to a driving transistor having a pixel structure. A pixel structure for reducing uniformity and threshold voltage variations; The present invention relates to a method for operating a light emitting diode pixel structure.                                Background of disclosure   Matrix displays are well known in the art and are illustrated in FIG. Pixels are illuminated using matrix addressing (illu minate). A typical display 100 is arranged in rows and columns (rows and columns). A plurality of pictures or display members (pixels) 160. The display is A ram data generator 110 and a row select generator 120 are incorporated. In operation, each row is activated sequentially through the row lines 130, and the corresponding column lines are activated. The corresponding pixel is activated using the button 140. Passive matrix de In the display, each row of pixels is illuminated one by one, but the active In a trix display, each row of pixels is initially contiguous with the data. Loaded.   The use of portable displays such as laptop computers Increasingly different display technologies (eg liquid crystal display (LCD) And light emitting diode (LED) displays). these An important difference between the two technologies is that LEDs are light emitting devices and non-light emitting devices (LCDs). Etc.) has an advantage in power efficiency. In LCD, fluorescent The backlight is on for the entire duration the display is in use and It consumes power even to "turn off" the cell. In contrast, LEDs (or OLED) displays illuminate only the activated pixels and provide an "off" pixel. Saves power by not lighting the lamp.   Displays employing OLED pixel structures can reduce power consumption. However, such a pixel structure can exhibit non-uniformity in intensity, It is due to the threshold voltages of the drive transistors and transistor non-uniformity due to manufacturing Due to theft. However, the brightness of the OLED is less than the current passing through the OLED. It turned out to be an example.   Therefore, the current non-uniformity and threshold in the “drive transistor” of the pixel structure There is a need in the art for pixel structures and associated methods for reducing voltage changes.                                Summary of the Invention   In one embodiment of the present invention, the current source is assembled into an LED (OLED) pixel structure. Current non-uniformity and threshold voltage in the pixel structure driving transistor. Reduce pressure changes. The current source is coupled to the data line, where a constant Current is programmed first and then collected.   In an alternative embodiment, an auto-zero voltage is determined and stored. Constant current achieved by applying a reference voltage first in the zero-phase Is done. Auto-zero voltage effectively accounts for the threshold voltage of the driving transistor . Next, a data voltage associated with the same reference voltage is now applied to illuminate the pixel. , Apply.   In another embodiment, the resistor is embedded within an LED (OLED) pixel structure And the dependence of the current through the OLED on the threshold voltage of the driving transistor. To reduce the sensitivity of existence.                             BRIEF DESCRIPTION OF THE FIGURES   The teachings of the present invention will take into consideration the following detailed description in connection with the accompanying drawings. Can be easily understood by:   FIG. 1 is a block diagram of the matrix addressing interface.   FIG. 2 is a circuit diagram of the active matrix LED pixel structure of the present invention. .   FIG. 3 shows an alternative embodiment of the active matrix LED pixel structure of the present invention. It is a circuit diagram of a state.   FIG. 4 shows another alternative implementation of the active matrix LED pixel structure of the present invention. It is a circuit diagram of an embodiment.   FIG. 5 has a multiple active matrix LED pixel structure of the present invention It is a block diagram of a system using a display.   FIG. 6 shows an alternative embodiment of the active matrix LED pixel structure of FIG. FIG.   FIG. 7 illustrates an alternative embodiment of the active matrix LED pixel structure of the present invention. It is a circuit diagram of a state.   For ease of understanding, where possible to show identical parts common to the figures Used the same reference numbers.                                Detailed description   FIG. 2 is a circuit diagram of an active matrix LED pixel structure 200 of the present invention. Is shown. In a preferred embodiment, the active matrix LED pixel structure For example, transistors manufactured using amorphous or polysilicon This is performed using a thin film transistor (TFT) that is a data source. Like, like In a preferred embodiment, the active matrix LED pixel structure is organic Incorporates a photodiode (OLED). This pixel structure is a thin film transistor And the invention is implemented using transistors and organic light emitting diodes. It is understood that it can be implemented using other types of light emitting diodes Must-have. For example, transistors manufactured using other materials If the threshold non-uniformity is exhibited as described above, the present invention may provide a constant power through the illumination member. Can be used to provide flow.   The invention is shown below as a single pixel or pixel structure, where the pixels are Can be used with other pixels (eg, in an array) to form a display. You have to understand that you can. In addition, the figure below shows a specific transistor shape. Shown, but without understanding that the source of the transistor corresponds to the voltage sign No.   Referring to FIG. The pixel structure 200 includes three PMOS transistors 2 40, 250, 260, NMOS transistor 270, capacitor 280 and L ED (OLED) 290 (light member) is included. Select line 210 is Stars 240, 250 and 270 are coupled to the gates. The data line is a tiger + V connected to the source of transistor 250_DDThe line is the drain of transistor 270 In. One electrode of OLED 290 is connected to transistor 240 and And 260 are connected to the drain. The source of transistor 240 is Coupled to the gate of transistor 260 and one terminal of capacitor 280 You. Finally, the drain of transistor 250, the source of transistor 270, The source of transistor 260 and one terminal of capacitor 280 are all 1 Are joined together.   The present pixel structure 200 has a large threshold voltage (V_t) In the presence of heterogeneity, uniform Provides current drive. In other words, maintaining a uniform current across the OLED, It is desirable to ensure uniformity in display strength.   More specifically, the OLED pixel structure has two phases, the load data phase It is operated in the dose and continuous lighting phases. Load data phase   Pixel structure 200 is driven by driving the appropriate select line 210. Data can be loaded. That is, when the select line is set to "low" , The transistor P4 (240) is turned “ON” and the voltage on the anode side of the OLED 290 is Pressure is sent to the gate of transistor P2 (260). At the same time, the transistor P 1 (250) is also turned “on” and a constant current from data line 220 is It flows through both transistor P2 (260) and OLED 290. That is, Transis The power 260 is turned on to reduce the current driven by the current source 230. The current source 230 for driving the data line is programmed by external data. ing. The gate to the source voltage of transistor 260 (drive transistor) Next, the voltage required for driving the current is determined. At the same time, the transistors N1 (2 70) is turned off and the power supply + V_DDIs disconnected from the OLED 290. one The constant current source 230 also self-adjusts the voltage from the source to the gate, The Eve value (voltage) is adapted to the transistor 260 and the polysilicon TFT 260 Compensate for threshold changes. The overdrive voltage indicates data. In order, data is memorized Capacitor C_S280 is stored appropriately. Now load for data Alternatively, the write cycle is completed. Continuous lighting phase   When the select line is set to "high", P1 (250) and P4 (24) 0) are turned off, and transistor N1 (270) is turned on. Is made. Although the power supply voltage of the transistor 260 may slightly change, The voltage from the source to the gate of transistor 260 is the current level during the lighting cycle. Control files. V of transistor 270 across capacitor 280_SGImmediately I can't change. Thus, the gate voltage of transistor 260 is Tracks the voltage and the voltage from the source to the gate determines the entire load and lighting phase. Maintained throughout. Polysilicon TFT leakage current and OLED gray scale The required voltage resolution for the pixel brightness is to hold the effective data of the frame time. Determine the size of storage capacitor needed for In a preferred embodiment, the Densers are on the order of 0.25 pf. That is, the current leakage of the transistor 260 The capacitor will be large enough to take into account. Now the lighting phase pixel motion Complete the work.   Each data / column line 220 has its own programmed constant current source 2 Note that it has 30. Following the data line during the lighting phase Is programmed to load the next row of all pixels, The previous row of pixels has been active for the entire frame time during the illumination phase. This Thus, the pixel structure of FIG. 2 has one NMOS transistor with 2.5 lines. Only three transistors and three PMOS transistors are required. (Share with adjacent pixels V that can be_DDVoltage supply, select line, data line current source).   Alternatively, FIG. 6 shows that the pixel structure of FIG. 4 illustrates an embodiment implemented with a PMOS or NMOS process only. Both are economical. The NMOS transistor N1 is a PMOS P It is replaced by three transistors 610. But additional lines (control lines) 620 is coupled to the gate of transistor 610 and includes an additional PMOS transistor To a total of 3.5 lines (ie, additional PMOS gates Additional voltage supply to control).   In short, the pixel structure of FIGS._SGOn Constant current source by self-adjustment / tracking mechanism and through OLED 290 By supplying the threshold voltage change of both the polysilicon TFT and the OLED. Designed to make up. In fact, the pixel structure of FIGS. And achieving proper operation with high voltage supply during both the lighting phase Can be. These pixel structures are OLED or pixel polysilicon TFT Good grayscale uniformity and high life despite instability in both What is done to design a high quality OLED display with time Can be.   FIG. 3 shows an alternative embodiment of the present active matrix pixel structure. Teens In an alternative embodiment, the data line voltage is converted to a current in the pixel structure. Does not require a voltage-to-current converter as in the current source implementation described above in FIGS. .   Referring to FIG. The pixel structure 300 has four PMOS transistors ( 360, 365, 370, 375), two capacitors 350 and 355 and L ED (OLED) 380 is included. Select line 320 is connected to transistor 360 Connected to the gate. Data line 310 is the source of transistor 360 Combined, + V_DDThe line connects the source of transistor 365 and the capacitor 355 It is connected to one terminal. Auto zero line 330 is transistor 3 The illumination line is coupled to the gate of transistor 375 Have been. One electrode of OLED 280 is connected to the drain of transistor 375 Are combined. The source of transistor 375 is connected to transistors 365 and 37 0 is connected to the drain. The drain of the transistor 360 is a capacitor 350 to one terminal. Finally, the transistor 365 Gate, the source of transistor 370, one terminal of capacitor 350 and One terminal of the capacitor 355 is all coupled.   More specifically, FIG. 3 illustrates a pixel structure 300 operated in three phases. Show. That is, 1) auto-zero phase, 2) load data phase, 3) lighting It's a daze. Auto zero   When the auto zero line 330 and the illumination line 340 are set to "low", Transistors P2 (375) and P3 (370) turn "on" and the transistor The voltage on the drain side of the transistor P1 (365) is sent to the gate and is temporarily Connected to the code. Data line 310 is set to "reference voltage" and select Line 320 is set low. Reference voltage can be set arbitrarily Yes, but it must be greater than the highest data voltage.   Next, the illumination line 340 is set to "high" and the transistor P2 375 Is turned off. The pixel circuit now has a transistor P1 365 (drive transistor). Transistor) and thus the data line reference voltage and the capacitor C_C The voltage which is the difference between the threshold voltage of transistor P1 365 at 350 (auto (Zero voltage). This allows the gate voltage, or more precisely, the transistor Star 365 V_SGIs set to the threshold voltage of the transistor 365. This is then Fixed overdriving on transistor P1 (365) regardless of threshold voltage change To provide the voltage. Finally, the auto-zero line 330 is set to "high", The gate of the transistor P1 365 is insulated. The purpose of Auto Zero is now Achieved. Load data phase   At the end of the autozero phase, the select line is set low and the The data line was at the "reference voltage". Now, the data line 310 is connected to the data voltage. Set. The data voltage is provided on the gate of transistor P1 (365). Sensor C_CSent through 350. Next, set the select line to “high”. Is done. Thus, the V of transistor 365_SGProvides a constant current level To provide a fixed overdrive voltage to transistor 365. This is The code data phase ends, and the pixel is now for illumination. Continuous lighting data phase during low phase of deselect Z   When the data voltage is stored on the gate of transistor P1 (365), the illumination IN 340 is set low and transistor P2 375 is turned "ON". It is. The current supplied by transistor P1 365 turns on OLED 380 Will be able to flow through. In short, transistor 365 is a constant Acts like a current source. This completes the lighting phase.   FIG. 4 shows another alternative embodiment of the present active matrix pixel structure. . In an alternative embodiment, the data line voltage is also the current within the pixel structure. Into a current source, as described above in FIGS. 2 and 6 for the current source. No piezo-current converter is required.   Referring to FIG. The pixel structure 400 has three PMOS transistors ( 445, 460, 465), two capacitors 450 and 455 and an LED (O LED) 470. Select line 420 is the gate of transistor 445 Is bound to. Data line 410 is coupled to the source of transistor 445 , VSWP lines are connected to the source of transistor 460 and one of the capacitors 455. To the terminal. The auto zero line 430 is connected to the gate of the transistor 465. Connected to the One electrode of OLED 470 includes a transistor 465 and 460 is coupled to the drain. The drain of transistor 445 is Connected to one terminal of the sensor 450. Finally, transistor 4 60 gates, the source of transistor 465 and one terminator of capacitor 450 The null and one terminal of the capacitor 455 are all coupled.   More specifically, FIG. 4 illustrates a pixel structure 400 operated in three phases. Show. That is, 1) auto-zero phase, 2) load data phase, 3) lighting It's a daze. Auto zero (VSWP) phase   VSWP (voltage to switch supply) is set to "lower (lower) voltage" Only the quantity “ΔV” is set. Here, the lower voltage is such that the OLED 470 has a small amount. Current (eg, on the order of nanoamps, depending on OLED characteristics) Is selected as The lower voltage is equal to the C coupled to the capacitor._C(450) and A floating node between the transistor P4 (445) and the floating node (f The transistor P1 (460) V_{G (P1)}Coupled through the gate of Auto Zero line 430 is then set "low". Transistor P1 (460) (Drive transistor) is closed by closing transistor P3 (465). Temporarily connected as an iod. Select line 420 then goes low. The "reference voltage" is applied to the data line 410. Any reference voltage Can be set, but must be greater than the maximum data voltage No. The pixel circuit can now be set to the threshold of transistor P1 460 You. Finally, the autozero line 430 is then set to "high" and the transistor The gate of P1 460 is insulated. The effect of the auto-zero phase is on the storage device Capacitor C_CIs to store the voltage (auto zero voltage) at 450, which is Difference between reference voltage on data line and transistor threshold voltage of P1 460 Represents This completes the auto-zero phase. Load data phase   At the end of the auto-zero phase, the select line is set low and Data line was "reference voltage". Next, the data line is Switch to lower voltage (data voltage) where changes in data are referred to by data available. In turn, the data voltage (data input) is loaded and the capacitor 450 And 455 to the gate of transistor P1 460. Transi The voltage V of the star 460_SGIndicates that the transistor P1 (460) has a fixed overdrive Provide voltage and drive OLED 470 current. That is, the data voltage is It is converted to an overdrive voltage on the star P1 460. Above capacitor 450 Is the cause of the threshold voltage of transistor P1 460, The overall overdrive voltage is now independent of the threshold voltage of transistor P1. C The rect line 420 is then set to "high". This is the load data Complete Illuminate data continuously during the deselect row phase   At the completion of the data load phase, the gate of transistor P1 460 is now Isolated except for capacitive coupling, the overdrive voltage to drive the OLED is Capacitor C_S455. Next, VSWP is the first higher (higher, h igher) voltage (lighting voltage). Then the VSWP went up and now the lighting There is enough voltage to drive the OLED to operate. That is, the select line 420 When set high, the transistors P3 (465) and P4 (445) Both are turned "off" and the data voltage is changed as before by the V_SG Remains stored on the Source-to-gate voltage V_{SG (P1)}Is all Maintained throughout the body lighting phase, which means that the current level through the OLED is Means certain. This completes the lighting cycle.   In short, FIG. 3 has four PMOS transistors and three and half lines A pixel structure using a single coupling capacitor is disclosed. (Auto Zero Rye And the VDDH voltage supply can both be shared). Figure 4 shows three PMOS transistor and one coupling capacitor with 2 and 1/2 lines A pixel structure using a pixel structure is disclosed. (VSWP for switching the power supply Illuminate both of these two pixel structures (shared with pixels) and V_{SG (P1)} With the above auto-zero and request ring current mechanism, polysilicon TFT and The above two (2) pixel structures that can compensate for the threshold change of the OLED also Implemented in polysilicon NMOS and in amorphous NMOS designs be able to.   The two (2) pixel structures of FIG. 3 and FIG. Good grayscale uniformity and length despite instability in the con TFT It can be implemented to design high quality OLEDs with long lifetime.   FIG. 7 is a circuit diagram of an active matrix LED pixel structure 700 of the present invention. Is shown. In a preferred embodiment, the active matrix LED pixel structure is Thin film transistor (TFT) (for example, polysilicon or amorphous silicon (Transistors manufactured using the same). Similarly, favorable fruit In an embodiment, the active matrix LED pixel structure comprises an organic light emitting diode (OLED). This pixel structure is based on thin film transistors and organic light emitting devices. It is implemented using photodiodes, but the invention is not limited to transistors and light emitting diodes. It must be understood that it can be implemented using other types of Absent.   The pixel structure 700 has a large threshold voltage (V_t) In the presence of heterogeneity, uniform Provides current drive. In other words, maintaining a uniform current through OLEDs It is desirable to ensure uniformity in display intensity.   Referring to FIG. The pixel structure 700 includes two PMOS transistors 7 10 and 720, capacitor 730, resistor 750 and LED (OLED) 7 40 (optical member). Select line 770 is the gate of transistor 710 Is joined to. Data line 760 is coupled to the source of transistor 710 Have been. One terminal of register 750 is the source of transistor 720 And one electrode of OLED 740 is connected to the drain of transistor 720. Have been combined. Finally, the drain of the transistor 710 and the transistor 720 The gate and one terminal of the capacitor 730 are all coupled.   More specifically, when the row containing the pixel structure is selected as the active row At this time, the logical “high” level of the select line 770 is Is turned on, and capacitor C730 is charged from data line 760 to voltage Vg. That can be done. Low is “Low” on select line 770 After being deselected by the bell, the transistor M1 is turned off and the capacitor 7 Thirty voltages are stored for the frame time. When the voltage is the transistor M2 72 Since it appears at the gate of 0, it draws current through transistor 720 and drains The OLED 740 is set so as to pass through.   More importantly, register 750 is implemented in the present pixel structure. . A resistor is coupled to the source of transistor 720 to provide a negative feed. Functions as a back member. Each drive transistor has an abnormally low threshold voltage If so, the transistor tends to pass more current to the OLED However, the additional current causes an additional brownout across resistor 750, To reduce the current.   Complementary effects occur on drive transistors with abnormally high threshold voltages. all The effect of the body is to reduce the non-uniformity of the current. Register achieved with TFT That is generally formed with much better resistance uniformity than the threshold voltage uniformity It turned out that I could do it. One reason is that the TFT threshold voltage is active silicon Dope used in resistors, even though it is very sensitive to the trap density of the material The resistance of the deposited layer is less sensitive to trap density. measured value Indicates that the percentage change in resistance is very small across the polysilicon display wafer Changes within the range where the resistance changes, unlike the transistor threshold It is expected to be.   The current passing through OLED 740 determines the brightness. But use TFT The threshold voltage of the TFT is also extended over the life as described above when the pixel is executed. It has been observed that the In addition, the initial threshold voltage of the TFT There will be uniformity. For a current whose threshold is determined through an OLED, the voltage Does not have a strong effect, such non-uniformity for transistor 710 It should be noted that this is not a problem. On the other hand, the driving transistor 720 Changes in the threshold voltage directly affect the current through the OLED.   More specifically, the current, I through the OLED in the pixel structure_OLDEIs Can be represented as K 'is the intrinsic transconductance parameter of transistor M2, and W and L are Width and length, V_tIs the threshold voltage, Vg is the voltage from the data line, R750 has a value of 1M in a preferred embodiment. However, the resistance value According to transistor characteristics, it can be 100K to 10M. This pixel structure Reduces the current variation to one third of the possible variation without the inventive register described below. It was observed that it could be reduced.   More particularly, a threshold value comprising a resistor coupled to the source of transistor 720 is provided. The sensitivities are as follows.   Although it is beneficial to increase the gate voltage Vg as much as possible, the transistor 720 Has the limitation that it must stay within saturation. Register (I_OLDER By causing a voltage drop across the threshold voltage, the sensitivity to threshold voltage changes It can be reduced below what can be achieved without star. Finally, the term (I_{OL DE} R) is (Vg-V_t) Cannot be larger than. The reason is that This is because the result means that the transistor 720 is turned off. Therefore, the tiger Can be achieved by placing a register in the source of transistor 720 The greatest reduction in sensitivity that can be achieved is a factor of two.   However, placing a register in the source increases the width W of transistor 720. And such an increase reduces the standard deviation of the threshold voltage. Fixed maximum Since the gate voltage, W, can be increased, σ_VtFrom statistical reduction within Bring out many benefits. Thus, placing the resistor at the source of transistor 720 Thus, the reduction in the current fluctuation is a combination of the following effects (1) and (2). Reduction (limited to a theoretical maximum benefit of 2 × or 50% reduction), and (2) threshold Change σ_VtWith its own reduction (no limits except geometric and capacitance constraints) is there.   FIG. 5 shows a plurality of active matrix LED pixel structures 200 of the present invention. System using display 520 having 300, 400, 600 or 700 FIG. 2 shows a block diagram of a program 500. The system 500 includes a display controller 5 10 and a display 520.   More specifically, the display controller is implemented as a general-purpose computer The computer may include a central processing unit CPU 512, a memory 514. And a plurality of I / O devices 416 (eg, a mouse, a keyboard, a storage device, for example, It has a magnetic and optical drive device, a modem, and the like. Activate display 520 The software instructions causing the CPU 5 to load 12 can be performed.   The display 520 includes a pixel interface 522 and a plurality of pixels ( Pixel structure 200, 300, 400, 600 or 700). Pixeli The interface 522 includes the pixels 200, 300, 400, 600, or 700. Includes circuits necessary for driving. For example, the pixel interface 522 1 may be the matrix addressing interface.   Thus, system 500 can be implemented as a laptop computer. Can be. Instead, the display controller 510 may be otherwise Can be implemented, for example, by a microcontroller or an application. Specific integrated circuit (ASIC) or combination of hardware and software instructions It is. In short, the system 500 incorporates the display of the present invention. It can be implemented in larger systems.   Although the invention has been described using PMOS transistors, the invention is not limited to NMOS transistors. It should be understood that it can be implemented using transistors. Note that the associated voltages are reversed there. That is, OLED is now NMOS It is coupled to the source of the driving transistor. Since the OLED is turned over, the OLED The sword must be made of a transparent material.   Various embodiments incorporating the teachings of the present invention are shown and described in detail herein. However, those skilled in the art will readily recognize many other various implementations that incorporate these teachings. The form can be devised.

────────────────────────────────────────────────── ─── Continuation of front page    (31) Priority claim number 09 / 064,697 (32) Priority date April 22, 1998 (April 22, 1998) (33) Priority country United States (US) (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE), JP, KR (72) Inventors Sue, James, Yakong             United States New Jersey             Edison Hana Road 7107 (72) Inventor Sue, Furang             United States New Jersey             Cranberry Kinglet Drive             South 14 (72) Inventors Ipri, Alfred, Charles             United States New Jersey             Princeton Cotswold Lane 7 (72) Inventor Stewart, Roger, Green             United States New Jersey             Neshanic Station Skied             Live 3

Claims (1)

[Claims] 1. A display (520) comprising a plurality of pixels, wherein each pixel (200) is a first transistor (250) having a gate, a source and a drain, the gate being coupled to a select line (210); A first transistor (250) having a source coupled to the data line (220); and a second transistor (270) having a gate source and a drain, wherein the gate of the second transistor is the select line. And a second transistor (270) having a drain coupled to the _VDD line (295) and a source coupled to the drain of the first transistor. A third transistor (240) having a gate, a source, and a drain, wherein the third transistor (240) comprises: A third transistor (240) having a gate coupled to the select line; and a capacitor (280) having a first terminal and a second terminal, wherein the source of the third transistor is the capacitor. A capacitor (280) coupled to the first terminal of the first transistor and the second terminal of the capacitor coupled to the drain of the first transistor; and a fourth transistor (260) having a gate, a source and a drain. ) Wherein a source of the fourth transistor is coupled to the drain of the first transistor and a gate of the fourth transistor is coupled to the source of the third transistor (260) and a light member (290) having two terminals, A lighting member (290), wherein the drain of the fourth transistor and the drain of the third transistor are coupled to one of the terminals of the lighting member. 2. The display of claim 1, further comprising a current source (230) for coupling to the data line. 3. A display (520) comprising a plurality of pixels, each pixel (600) being a first transistor (250) having a gate, a source and a drain, the gate being coupled to a select line (210). A first transistor (250) having a source coupled to the data line (220); and a second transistor (610) having a gate source and a drain, wherein the gate of the second transistor has a control line ( 620), the source of the second transistor being coupled to the _VDD line (295), and the drain of the second transistor being coupled to the drain of the first transistor ( 610) and a third transistor (240) having a gate, a source, and a drain. A third transistor (240) having a gate coupled to the select line, and a capacitor (280) having a first terminal and a second terminal, the source of the third transistor being the capacitor. And a fourth transistor having a gate, a source and a drain, wherein the second terminal of the capacitor is coupled to the drain of the first transistor. 260) wherein a source of the fourth transistor is coupled to the drain of the first transistor and a gate of the fourth transistor is coupled to the source of the third transistor (260) and a lighting member (290) having two terminals, Display drains and the third transistor of the fourth transistor comprises an illumination member (290) coupled to one of said terminals of said illumination member (520). 4. A method of illuminating a display having a plurality of pixels including driving transistors, wherein each pixel includes a circuit for controlling application of energy to a lighting member, the method comprising: (a) applying a current to a data line; Loading the pixel with data; (b) storing the data in a capacitor coupled to a driving transistor; and (c) illuminating the lighting member according to the stored data. 5. 5. The method of claim 4, wherein said current is provided by a current source. 6. A display (520) comprising a plurality of pixels, each pixel (300) being a first transistor (360) having a gate, a source and a drain, the gate being coupled to a select line (320); A first transistor (360) having a source coupled to the data line (310); a first capacitor (350) having a first terminal and a second terminal; A first capacitor (350) having a drain coupled to the first terminal of the first capacitor; and a second transistor (365) having a gate, a source, and a drain, wherein A source is coupled to the V _DD line (390) and the gate of the second transistor is connected to the second capacitor of the first capacitor. A second transistor (365) coupled to the first transistor and a second capacitor (355) having a first terminal and a second terminal, wherein the gate of the second transistor is connected to the second capacitor (355). A second capacitor coupled to the first terminal, the source of the second transistor coupled to the second terminal of the second capacitor; and a third capacitor having a gate, a source, and a drain. The transistor (370), wherein the gate of the third transistor is coupled to an auto-zero line (330), the source of the third transistor is coupled to the gate of the second transistor, A third transistor (370) having a drain of the transistor coupled to a drain of the second transistor; A fourth transistor (375) having a source and a drain, the gate of the fourth transistor being coupled to the illumination line (340), and the source of the fourth transistor being coupled to the drain of the third transistor. A lighting member (380) having a fourth transistor (375) and two terminals, wherein the drain of the fourth transistor is coupled to one of the terminals of the lighting member. (380) A display comprising:. 7. A display (520) comprising a plurality of pixels, wherein each pixel (400) is a first transistor (445) having a gate, a source and a drain, said gate being coupled to a select line (420). , A first transistor (445) having a source coupled to a data line (410), and a first capacitor (450) having a first terminal and a second terminal, wherein the first transistor (445) has a first terminal and a second terminal. A first capacitor (450) having a drain coupled to a first terminal of the first capacitor; and a second transistor (460) having a gate, a source, and a drain, the source of the second transistor. Is coupled to the VSWP line (440), and the gate of the second transistor is connected to the second capacitor of the first capacitor. A second transistor (460) coupled to a terminal; and a second capacitor (455) having a first terminal and a second terminal, the gate of the second transistor being connected to the second capacitor (455). A second capacitor coupled to a first terminal, the source of the second transistor coupled to a second terminal of the second capacitor; and a third transistor having a gate, a source, and a drain. (465) wherein the gate of the third transistor is coupled to an auto-zero line (430), the source of the third transistor is coupled to the gate of the second transistor, and the drain of the third transistor Has a third transistor (465) coupled to the drain of the second transistor, and two terminals. An illumination member (470), a display including an, an illumination member (470) coupled to one of the second drain of the transistor of the illumination member terminal. 8. A method for illuminating a display having a plurality of pixels, wherein each pixel includes circuitry for controlling application of energy to a lighting member, said circuitry illuminating the display having a plurality of pixels including a driving transistor. (A) determining an auto-zero voltage for the driving transistor by applying a reference voltage to a data line; and (b) switching the reference voltage to the data voltage of the data line, thereby providing Loading the data; (c) storing the data in a capacitor coupled to a driving transistor; and (d) illuminating the lighting member according to the stored data. 9. A circuit (300) for driving a lighting member having two terminals, a first transistor (360) having a gate, a source and a drain, the gate for connecting a select line (320). Wherein the source is a first transistor (360) for connecting the data line (310), and a first capacitor (350) having a first terminal and a second terminal. A first capacitor (350) having a drain of the first transistor coupled to a first terminal of the first capacitor; and a second transistor (365) having a gate source and a drain. , the source of the transistor of the second is coupled to V _DD line (390), the gate of the second transistor is a first con A second transistor (365) coupled to said second terminal of the sensor; and a second capacitor (355) having a first terminal and a second terminal, wherein the gate of said second transistor is A second capacitor coupled to a first terminal of the second capacitor, the source of the second transistor coupled to a second terminal of the second capacitor; a gate, a source, and a drain. A third transistor (370) having the gate of the third transistor coupled to an auto-zero line (330), the source of which is the source of the second transistor. A third transistor coupled to the gate and the drain of the third transistor coupled to the drain of the second transistor; A fourth transistor (375) having a transistor (370), a gate, a source, and a drain, the gate of the fourth transistor being coupled to an illumination line (340); A third transistor coupled to a drain of the third transistor, and a drain of the fourth transistor coupled to a lighting member. . 10. A system (500) comprising: a display controller (510); and a display (520) coupled to the display controller, wherein the display includes a plurality of pixels, the pixels (300) comprising: a gate, a source, and A first transistor (360) having a drain, the gate coupled to the select line (320), and the source coupled to the data line (310); A first capacitor (350) having a terminal and a second terminal, a first capacitor (350) having a drain of the first transistor coupled to a first terminal of the first capacitor; A second transistor (365) having a gate, a source, and a drain, The source of the second transistor is coupled to V _DD line (390), a second transistor having a gate of the second transistor is coupled to said second terminal of said first capacitor and (365), the A second capacitor (355) having a first terminal and a second terminal, wherein the gate of the second transistor is coupled to the first terminal of the second capacitor, and the source of the second transistor is Is a second capacitor (355) coupled to a second terminal of the second capacitor; and a third transistor (370) having a gate, a source and a drain, wherein the gate of the third transistor is An auto-zero line (330), the source of the third transistor being coupled to the gate of the second transistor, and the third transistor A third transistor (370) having a drain of the transistor coupled to the drain of the second transistor; and a fourth transistor (375) having a gate, a source, and a drain, the gate of the fourth transistor. Is coupled to an illumination line (340), a source of the fourth transistor is coupled to a drain of the third transistor (375), and an illumination member (380) having two terminals. A lighting member coupled to one of the terminals of the lighting member, wherein the drain of the fourth transistor is coupled to one of the terminals of the lighting member. 11. A display (520) comprising a plurality of pixels, each pixel (700) being a first transistor (710) having a gate, a source and a drain, the gate being coupled to a select line (770). A first transistor (710) having a source coupled to the data line (760); and a second transistor (720) having a gate, a source, and a drain, wherein the drain of the first transistor is the second transistor (720). A second transistor (720) coupled to the gates of two transistors; and a register (750) having two terminals, the source of the second transistor coupled to one of the terminals of the register. And a lighting member (740) having two terminals. A lighting member (740) having a transistor drain coupled to one of the lighting member terminals.