CN105637575A

CN105637575A - System and methods for power conservation for AMOLED pixel drivers

Info

Publication number: CN105637575A
Application number: CN201480055123.3A
Authority: CN
Inventors: 戈尔拉玛瑞扎·恰吉; 贾马尔·索尼
Original assignee: Ignis Innovation Inc
Current assignee: Ignis Innovation Inc
Priority date: 2013-10-21
Filing date: 2014-10-06
Publication date: 2016-06-01
Anticipated expiration: 2034-10-06
Also published as: WO2015059593A1; CN105637575B

Abstract

A system is provided for conserving energy in an AMOLED display having pixels that include a drive transistor and an organic light emitting device, and an adjustable source of a supply voltage for the drive transistor. The system monitors the content of a selected segment of the display, sets the supply voltage to the minimum supply voltage required for the current content of the selected segment of the display, determines whether the number of pixels requiring a supply voltage larger than the set value is greater than a predetermined threshold number, and, when the answer is negative, reduces the supply voltage by a predetermined step amount.

Description

System and method for the power save of AMOLED pixel driver

Technical field

The present invention relates generally to displayer, and particularly relate to the power consumption on certain high brightness situation this display of saving.

Background technology

Currently, active matrix organic light-emitting device (" AMOLED ") display is just being proposed. The advantage of this display includes lower power consumption, manufactures flexibly and faster refresh rate. Contrary with traditional LCD display, displayer does not have backlight, and each pixel is made up of independent luminous different OLED. The power consumed in each pixel has relation with the size of the light of generation in this pixel. Typical pixel includes organic luminescent device and thin film drive transistor. Program voltage is applied to the grid driving transistor, and it substantially drives transistor to the current in proportion of luminescent device with flowing through. But, the use of electric current makes the performance of pixel depend on driving transistor, and the characteristic of this driving transistor is likely to change, because current many this transistors are manufactured by non-crystalline silicon. Such as, the threshold voltage of amorphous silicon transistor is likely in life-time service to drift about, result in and cause due to drift the data from program voltage to be applied improperly.

Although known active matrix organic light-emitting diode (AMOLED) display has low average power consumption, but still could possibly be higher than AMLCD (AMLCD) in peak brightness place power consumption. This makes the less application obtaining such as Email, surfing on the net and e-book etc of displayer, because showing this application requirement substantial amounts of white (high brightness) background. The power dissipation associated with thin film drive transistor and OLED itself is depended in power dissipation in displayer. Although the development of greater efficiency OLED continues to significantly decrease the power consumption of display, but the power consumption of the electric current OLED display in the application requiring high brightness is more than comparable AMLCD. It is thus desirable to the new method in TFT operation reduces power further. Accordingly, there is a need for reducing power consumption in certain brightness conditions to compensate the method for power requirement increased.

Summary of the invention

The aspect of the disclosure includes the circuit of the voltage-programming of the current offset of a kind of pixel for display. Described circuit includes: the controlled power voltage source of output supply voltage. Organic luminescent device launches the light of the luminance level with the function as electric current. Transistor is driven to have the drain electrode coupled with described controlled power voltage source and the source electrode coupled with described organic luminescent device. Described driving transistor has the grid input being inputted control by the program voltage for determining the electric current by luminescent device. In order to save energy, the content of the selection section of display described in described system monitoring, described supply voltage is set as described display described selection section Current Content needed for minimum power source voltage, judge that whether the quantity needing the pixel of the supply voltage bigger than set value is more than reservation threshold quantity, and when answering as negative, described supply voltage is reduced predetermined step-size amounts.

The various embodiments carried out in view of reference accompanying drawing and/or the detailed description of aspect, it will be appreciated by one of skill in the art that the above-mentioned and other aspect of the present invention and embodiment, next provides the Short Description of accompanying drawing.

Accompanying drawing explanation

When reading described in detail below and when reference accompanying drawing, the above-mentioned and further advantage of the present invention will become apparent from.

Fig. 1 is the block diagram of displayer;

Fig. 2 is the block diagram of the pixel driver circuit for the displayer in Fig. 1;

Fig. 3 is the diagram of the voltage level of the different mode that the power consumption for the pixel driver circuit in Fig. 2 is saved;

Fig. 4 is alternative pixel driver circuit, and it can use power consumption to control while controlling voltage drop and preventing threshold voltage shift;

Fig. 5 is the sequential chart controling and data signal for the drive circuit in Fig. 4;

Fig. 6 is the power consumption diagram that the example driver circuit for different graph images contrasts traditional displayer;

Fig. 7 is the schematic diagram of the source of power consumption in electroluminescent display;

Fig. 8 is the flow chart of the technology for adjusting the supply voltage for image element circuit based on the content of the selection section of display and reservation threshold;

Fig. 9 is for the content of the selection section of display to solve the flow chart of the algorithm of the value of minimum power source voltage;

Figure 10 is the flow chart of the process for compensating the mains voltage variations about other compensating factor; And

Figure 11 is the flow chart that use effect matrix (effectmatrix) compensates the development of mains voltage variations.

Although the present invention is vulnerable to various amendment and alternative form, but specific embodiment has illustrated by way of example in the accompanying drawings and will be described in detail in this application. It is to be appreciated, however, that the present invention is not intended to be limited to disclosed specific form. On the contrary, the present invention covers all modifications, equivalent and the replacement scheme that fall in the spirit and scope of the present invention as defined by the appended claims.

Detailed description of the invention

Fig. 1 is the electronic display system 100 with active matrix area or pel array 102, and in this pel array 102, the array of pixel 104 is arranged with the configuration of row and column. In order to facilitate example, illustrate only two row and two row. It is outer peripheral areas 106 in the outside of the active matrix area of pel array 102, is wherein provided with the peripheral circuit for driving and control pel array 102. Peripheral circuit includes grid or address driver circuits 108, source electrode or data driving circuit 110, controller 112 and supply voltage (such as, Vdd) driver 114. Controller 112 control gate driver 108, source electrode driver 110 and supply voltage driver 114. Address wire or selection line SEL [i], SEL [i+1] etc. are operated by gate drivers 108 under the control of controller 112, have an address wire for the every a line in the pixel 104 in pel array 102 or select line. The video data processed is fed in controller 112 by video source 120, in order to be shown in display system 100. Video source 120 represents from any video that the device of the such as use display system 100 of computer, cell phone, PDA etc. exports. The video data processed is converted to the voltage-programming information of suitable pixel 104 on display 100 system 100 by controller 112.

In the configuration that following pixel is shared, grid or address driver circuits 108 can also alternatively the overall situation be selected line GSEL [j] and alternatively right/GSEL [j] be operated, the overall situation selects line GSEL [j] or/GSEL [j] that the multiple row (every two row of such as pixel 104) in the pixel 104 in pel array 102 are operated. Voltage data line Vdata [k], Vdata [k+1] etc. are operated by source driver circuit 110 under the control of controller 112, show a voltage data line for each in the pixel 104 in pel array 102. The voltage-programming information of the brightness of each luminescent device in each pixel 104 transport expression pixel 104 given by voltage data line. Memory element (such as capacitor) in each pixel 104 stores voltage-programming information until transmitting or drive cycle make luminescent device turn on. Supply voltage driver 114 controls the voltage level on supply voltage (EL_Vdd) line under the control of controller 112, has a power voltage line for the every a line in the pixel 104 in pel array 102. Alternately, voltage driver 114 can be individually controlled the level for the every one-row pixels 104 in pel array 102 or the supply voltage of the every string pixel 104 in pel array 102. As will be described, the brightness as requested of the level of supply voltage and be adjusted to save the power consumed by pel array 102.

As it is known, each pixel 104 in display system 100 needs to be programmed for the information of the brightness of the organic luminescent device in the pixel 104 of particular frame with instruction. One frame defines the time period including programming cycle or stage and driving or transmitting cycle or stage, each pixel in display system 100 is programmed with the program voltage representing brightness in programming cycle or during the stage, and drive or during transmitting cycle or stage each luminescent device in each pixel switched on so that the Intensity LEDs to match with the program voltage being stored in memory element. Therefore frame is composition one in many still images of the complete moving image of display in display system 100. At least exist for programming and drive the two schemes of pixel: line by line or frame by frame. In programming line by line, one-row pixels is programmed and was driven before next line pixel is programmed and drives subsequently. In programming frame by frame, first the pixel of all row in display system 100 is all programmed, and all pixels are driven row. Any one scheme can adopt the brief vertical blanking time of the beginning at each frame or end place, and during this vertical blanking time, pixel is both unprogrammed is not driven yet.

It is arranged in the outer peripheral areas 106 around pel array 102 that the assembly outside pel array 102 can be arranged on the same physical substrate being provided with pel array 102 thereon. These assemblies include gate drivers 108, source electrode driver 110 and supply voltage and control 114. Alternately, some assemblies in outer peripheral areas can be disposed on the substrate identical with pel array 102 that other assembly is arranged on different substrates, or all component in outer peripheral areas can be disposed on the substrate different from the substrate being provided with pel array 102 on it. Gate drivers 108, source electrode driver 110 constitute display driving circuit together with controlling 114 with supply voltage. Display driving circuit in some configuration can include gate drivers 108 and source electrode driver 110 but not include supply voltage and control 114.

The application (such as Email, Internet surfing etc.) that AMOLED display system 100 in Fig. 1 is used for having bright background requires higher power consumption, since it is desired that each pixel is used as the light source of this application. But, when pixel is switched to gray level (brightness) in various degree, still use the identical supply voltage driving transistor being applied to each pixel. Therefore, current representation management for requiring the supply power driving transistor of the video data of higher brightness, therefore with have to result compared with the usual displayer of the constant supply voltage driving transistor obtain maintain required luminous while save power.

Fig. 2 is the circuit diagram of the simple individual driver circuit 200 of the pixel for the pixel 104 in such as Fig. 1 etc. As explained above, each pixel 104 in the pel array 102 in Fig. 1 is driven by the drive circuit 200 in Fig. 2. Drive circuit 200 includes the driving transistor 202 being couple to organic luminescent device 204. In this example, organic luminescent device 204 is the luminous organic material of the function of the amplitude being electric current by current activation and its brightness. Supply voltage input 206 is couple to the drain electrode driving transistor 202. Supply voltage input 206 produces the electric current in luminescent device 204 together with driving transistor 202. Current level can control via with the program voltage input 208 driving the grid of transistor 202 to couple. Therefore program voltage input 208 is couple to the source electrode driver 110 in Fig. 1. In this example, driving transistor 202 is the thin film transistor (TFT) manufactured by amorphous silicon hydride. Certainly, technology described here can use together with the driving transistor manufactured by other semi-conducting material. Other circuit unit (not shown) of such as capacitor and transistor etc can be added to simple drive circuit 200, in order to allows pixel to utilize various enable, selection and control signal (those of gate drivers 108 input in such as Fig. 1) to be operated. This assembly is for the more rapid programming of pixel, the programming keeping pixel during different frame and other function.

When such as requiring that in the application of such as Email or surfing on the net etc pixel 104 has high-high brightness, the grid driving transistor 202 is driven such that transistor 202 is in saturation mode and therefore fully opens, allow high-current flow to cross organic luminescent device 204, produce high-high brightness. The relatively low brightness level of luminescent device 204 (such as relatively low gray level those) is by being controlled the Control of Voltage to the grid driving transistor 202 in linear zone. When driving transistor 202 to work in this region, grid voltage controls to be supplied to the electric current of luminescent device 204 linearly, and therefore controls the brightness of luminescent device linearly. In power save mode in this example, it is lowered with the power consumption driving transistor 202 to be associated, the current level to luminescent device 204 that will still maintain generation and the brightness roughly the same compared with the brightness that high power supply voltage can produce compared with low supply voltage because along with driving transistor 202 to be driven in saturation mode at certain threshold voltage place, on threshold voltage.

Fig. 3 illustrates four different modes of the power consumption adjusting mains voltage level 300. First mode has relatively high actuator voltage level 302, and its result obtains the highest brightness. Second pattern has relatively low voltage level 304, because it is so bright not require as element, such as requires to allow the gray level in the region of the enough grid voltage control of required brightness. 3rd pattern has relatively low voltage level 306, and its result obtains dark tone (shade). Actuator voltage is reduced to low level 308 by fourth mode. Constant mains voltage level 310 represents that wherein supply voltage is maintained at traditional AMOLED drive circuit of a level. Change to the supply voltage driving transistor according to the brightness requirement of pixel 104, result obtain relative to the traditional OLED pixel represented by voltage level 310 about 40% the saving of power consumption. It is to be understood that, it is possible to there is any number of different power level.

Level from the supply voltage of the supply voltage input 206 in Fig. 2 is controlled by the voltage controller 114 in Fig. 1. The control of supply voltage can based on the electric current required by display system 100, and it is based on the comparison of the display currents sensed Yu certain threshold level. The example measuring display currents determines that the total current from the power supply being connected with display system 100. In this example, the display currents sensed and threshold level are compared by controller 112, and regulate the supply voltage supplied by voltage controller 114 when exceeding different threshold levels to save power consumption. Higher electric current may indicate that supply voltage can be lowered to the level still realizing required brightness. Reduced-current is mostly in the situation of the dark gray level not requiring brighter level in pixel uses low voltage by allowing.

Alternately, it is possible to during Video processing, carry out this based on the amount of overall brightness required in particular video frequency frame determine, the video data that the amount of this overall brightness receives based on the video source 120 from Fig. 1. Can carry out this determining via the Video processing software on the device that the video source 120 of the display system 100 used in Fig. 1 is associated or by controller 112. Such as, when smooth gradient image (from black to entirely white transition gradually), if gradient keeps identical without unexpected jump, profile (contouring) effect or gamut between frames, then controller 112 may determine that picture quality does not change and can supply voltage be adjusted. In this example, via public voltage supply line, supply voltage is controlled at identical level place by each pixel in display 100. But, the supply voltage (such as the supply voltage of every one-row pixels or every string pixel) of the pixel of different sections can be independently controlled, for more accurate power save. Can preferably for the bigger display execution independent Control of Voltage driving transistor for the pixel of different sections, described bigger display for having bigger luminance level change to framing on different pixels.

Driving transistor 202 to have saturation region, in this saturation region, relative to the voltage (such as inputting the supply voltage of 206 from the supply voltage in Fig. 2) being applied to source electrode and drain electrode two ends, electric current is constant. At relatively low gate voltage level place, by the current level of transistor and grid voltage, there is linear relationship. Transition region is present between linear zone and saturation region. Saturation region maintains substantially invariable electric current for any voltage level on threshold voltage. It has been required for being operated in saturation region, because high with the contact resistance that particularly amorphous silicon film transistor (such as driving transistor 202) is associated.

Therefore, the running voltage of pixel should be chosen to drive transistor 202 be maintained at the degree of depth saturated in so that the crosstalk of voltage drop reduced in the supply voltage input 206 being derived from power save mode. Therefore pixel 104 is utilized the high electric current of luminescent device 204 and programs, in order to therefore so that it becomes drive the function of the approximately linear of the voltage at transistor 202 two ends. In this case, the high electric current required by luminescent device 204 causes source negative feedback (sourcedegeneration) effectively, therefore reduces the voltage drop impact on driving transistor 202. Additionally, during leak time, making pixel current is normal level, and it is further compensate for voltage drop. As a result, display brightness keeps identical. When maximum brightness level required by pixel 104 is in application (such as Email and web page browsing), this effect makes the power of driving transistor 202 reduce more than 50% and make total power consumption reduce 40%.

But, owing to driving transistor 202 to drift about to maintain the high electric current needed for luminescent device 204 directed through the linear zone of the operation of relatively low supply voltage, therefore picture quality is subject to the impact of source and earthing pop-corn (groundbouncing) and voltage drop. But, owing to gray level separates (apart) further in the application (such as Email) of major requirement bright pixel, therefore picture quality will not be interfered significantly on. In order to maintain identical brightness, the program voltage input to the grid driving transistor 202 can be controlled by regulating gamma curve. Fig. 4 illustrates the alternative drive circuit 400 for display picture element (pixel 104 in such as Fig. 1), and but it can use voltage supply to control allowable voltage drop and source and earthing pop-corn. Drive circuit 400 can be operated in saturated-linear transition region or even be further decreased in the linear zone of driver transistor, and result obtains significant power and reduces and do not cause any image artifacts.

Drive circuit 400 includes driving transistor 402, drives the source electrode of transistor 402 and organic luminescent device 404 to couple. Program voltage input 406 couples with the grid driving transistor 402 by selecting transistor 408. Select the grid that transistor 408 has and selects input 410 to couple. The selection signal in input 410 is selected to allow the program voltage signal in program voltage input 406 to regulate by driving transistor 402 to arrive the electric current of luminescent device 404. Program voltage input 406 couples with the drain electrode selecting transistor 406. The source electrode selecting transistor 408 is couple to the grid driving transistor 402 and the grid of biasing transistor 412, and the grid of biasing transistor 412 is by series wiring to another biasing transistor 414. When selecting transistor 408 to turn on, source capacitor 416 is charged to program voltage. Control signal input 420 couples with the grid biasing transistor 414. Controlled supply voltage input 422 is couple to the drain electrode driving transistor 402. The supply voltage 422 of input controls via voltage controller (voltage controller 114 in such as Fig. 1), and described voltage controller is for regulating power source voltage level and therefore saves the power for drive circuit 400.

Fig. 5 is the sequential chart during a frame of the pixel powered by drive circuit 400 for the signal selecting input 410, control input 420 and programming input 406 in Fig. 4. When selection signal in signal input 410 is imported into selection transistor 408, transistor 408 is switched on, allowing program voltage signal input 406 that source capacitor 416 is charged to program voltage level, described program voltage level will produce by driving transistor 402 to arrive the suitable electric current of organic luminescent device 404. This part in cycle utilizes the suitable luminance level based on program voltage signal input 406 that image element circuit 400 is programmed. By using biasing transistor 412 and 414 to eliminate voltage drop and source and earthing pop-corn.

As it is shown in figure 5, the control signal that the next part in this cycle makes the control signal input 420 selecting signal to disconnect and making the grid with transistor 414 couple in signal input 410 is connected. It is strobed (strobed) for, time low, selecting transistor 408 to be cut off so that program voltage is kept by the voltage of storage in capacitor 416 selecting the selection signal in signal input 410. Control signal input 420 makes biasing transistor 414 turn on. Therefore the control signal in control signal input 420 makes it possible to utilize charge leakage to carry out voltage compensation. In next cycle, then the control signal in control signal input 420 is gated low, and it makes transistor 414 end so that the program voltage being stored on capacitor 416 is coupled between grid and the source electrode driving transistor 402. Data program voltage to grid makes the electric current obtaining luminescent device 404 by driving transistor 402 to adjust. Therefore pixel is switched on during this period and keeps inputting from program voltage the program voltage level of 106. Inputting the control signal of 420 to control signal and then uprise, it makes pixel end, and therefore the electric current driving transistor 402 is flow through in decay (relax). Due to the negative bias caused by biasing transistor 412 and 414, therefore transistor 402 recovers sizable part of threshold voltage shift and thus extends the life-span of transistor 402.

Therefore when control signal inputs 420 quilt second time gating, the display circuit 400 in Fig. 4 ends the fraction of lasting frame time. Due to the major part for frame time, circuit 400 is not turned on, and therefore during the cut-off period, threshold voltage shift can be resumed. While circuit ends, drive transistor 402 to be utilized large-current electric via power supply voltage signal 422 and put down and add stress. This cycle makes the threshold voltage shift uniform (even) of all pixels in display, thus reduces differential ageing impact. Drive transistor 402 to be biased by negative ground during recovering the period, thus recover sizable part of threshold voltage shift for extending the life-span driving transistor 402 and the life-span therefore extending pixel. This decreases the threshold voltage driving transistor 402 with the factor of about 3. Therefore the drive circuit 400 in Fig. 4 allow bucking voltage drop with the impact of crosstalk while use less to drive transistor 402 supply voltage.

Drive circuit 400 in Fig. 4 also allows for compensating the voltage drift of the threshold voltage driving transistor 402 caused due to the supersaturation of more low driving voltage level. When more low-voltage is applied in driving transistor 402 two ends, it may result in coming from the higher threshold voltage shifts of the carrier of the increase of raceway groove, and it causes again the aging faster of transistor 402. Owing to there is biasing transistor to 412 and 414, voltage in Fig. 4 is of a relatively high, therefore drive transistor 402 not to be driven in the transition region time as so grown when using relatively low voltage, therefore stablize long-term threshold voltage shift and increase the life-span of transistor 402.

Fig. 6 is the diagram of the saving of the power aspect of AMOLED pixel display that illustrate the AMOLED pixel display compared to the standard using stabilized power source voltage, that use adjustable supply voltage to control. The application with high brightness output can obtain significant power save. Bar 602 illustrates the low power level when showing whole white screen with the displayer from use procedure outlined above compared with the bar 612 of standard displayer. Other application (such as brighter image (such as, start menu)) is as represented by the bar 608 of the lower power consumption of the displayer illustrating adjustable source voltage compared with the bar 618 of the power consumption illustrating standard displayer. Less power save compared with the bar 614 of the power represented by tradition displayer consumption and bar 616 when bar 604 is shown in pixel dark (less brightness) with bar 606.

Fig. 7 is the schematic diagram of the source of power consumption in electroluminescent display. As it can be seen, source of power consumption is dead resistance (contact resistance: R_con, line resistance: R_sup1And R_sup2), thus driving the voltage at element and load elements two ends to decline. Power consumption can be reduced in the following way: improve load efficiency with in more low-voltage with more operate under low level of current; And improve the performance driving element to reduce operation voltage. And, for any given device, drive condition can be optimized, so that it only needs minimum power capability.

In most of display, being adjusted by supply voltage to worst situation, worst situation includes the worst voltage drop at dead resistance two ends plus the worst voltage drop driving element and load elements two ends. Supply voltage can be adjusted based on the content of display. In the case, adjust supply voltage based on long hysteresis loop (longhysteresiscurve), to eliminate any sudden change in display. Therefore, can not effectively work when showing dynamic content (such as, video).

Fig. 8 is the flow chart of an embodiment of the technology for adjusting supply voltage based on the content of the section of display and reservation threshold. This technology does not need hysteresis loop. Supply voltage was adjusted before or after updating the little section of display. Owing to the change of the content of display segment is minimum during these adjust, so supply voltage gradually changes. Therefore, it is to avoid the sudden change of voltage.

In step 801 in fig. 8, calculate or measure the time delay changed needed for supply voltage, or time delay is set to default value (defaultvalue). Then, in step 802, when taking into account time delay, supply voltage is set as the minimum voltage needed for the Current Content of display segment. Step 803 calculates minimum power source voltage, and this minimum power source voltage causes that the quantity needing the pixel of the supply voltage bigger than set value is less than predetermined threshold number. Then, in step 804 supply voltage is set as computed value, and updates the content of display segment in step 805.

Fig. 9 is the flow chart of the specific embodiment of the algorithm of the value for solving the minimum power source voltage used in the step 803 in Fig. 8. In fig .9, the first two steps 901 is identical with two steps 801 in Fig. 8 and 802 with 902. Then, in step 903 supply voltage being set as selective value, hereafter step 904 judges that whether the quantity needing the pixel of the supply voltage bigger than set value is more than reservation threshold quantity. The threshold values quantity used in step 904 is defined as and can operate under the supply voltage less than required supply voltage and have no substantial effect on the quantity of the pixel of picture quality. If the answer is in the negative in step 904, then the setting value of supply voltage is reduced predetermined step-size amounts by step 905. Due to, image content-based and need the quantity of the pixel of high power supply voltage generally in any given image (or frame) for smallest number, and the step-length to next more low supply voltage is big, so this enables display to operate under less supply voltage. If answer is yes in step 904, then the value that practical power voltage is set as in step 902 selecting by step 906, and in step 907, then update the content of display segment.

In another embodiment, make driving element operate in linear zone, wherein drive element in linear zone, mains voltage variations is sensitive. This pattern can be used for picture material and is restricted the situation of (such as, only minority shade of gray). However, it is possible to extended the application of this operation by the mains voltage variations at compensation panel two ends. These factors it are contemplated that the such as inhomogeneities to display or the compensation of the other factors such as aging, because may interfere significantly on mains voltage variations. There are the technology of the different change in voltage for extracting display two ends and the two kinds of technology that will illustrate in these technology according to other compensating factor. Both technology can with other exchange of skills.

Figure 10 is the flow chart of the process for compensating the mains voltage variations about other compensating factor. Here, the effective resistance that several virtual (or the physics) in calculation display is put in step 1001. In step 1002a, the situation of pixel current can be directly affected for the efficiency compensation etc. of such as gamma, brightness, color dot and load elements, compensate video signal, and in step 1002, calculate the electric current through each selected element. Then, in step 1003, by using the effective resistance of each point, calculate the voltage drop of each point and this voltage drop is used for calculating the accumulation voltage drop of each point. In step 1004, when using the distinct methods such as such as interpolation, by using the active voltage that the voltage drop extracted calculates each pixel to drop.

Step 1005 compensates mains voltage variations and other compensating factor (such as, the Part II of backboard and OLED). Here, the order of compensating factor can be based on the reduction of reduction and the computational complexity calculating error. In step 1006, drop based on pixel voltage and adjust signal value. Step 1007 compensates the decline of backboard and OLED, and then in step 1008, display floater is programmed.

Figure 11 uses effect matrix to compensate the flow chart of the improvement embodiment of mains voltage variations. In step 1101, measure for each or calculate effect matrix. This matrix shows the impact on the supply voltage of other point of the electric current through this point. Therefore, effect matrix is used to perform the calculating of mains voltage variations in the following way: to calculate the electric current (step 1102) through each point, use matrix effect calculate the impact (step 1103) of each electric current and calculate the active voltage of each pixel and drop (step 1104). Then, in step 1105 is to 1107, perform above-mentioned identical compensation, adjustment and programming step.

Although it has been shown and described that only certain embodiments of the present invention and application, it is to be understood that, the invention is not restricted to disclosed accurate structure and layout in this application, and various amendments, change and change can be understood according to foregoing description when without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims

1. the method for the energy saved in active matrix organic light-emitting device display, described active matrix organic light-emitting device display has the pixel including driving transistor and organic luminescent device and has the scalable source of supply voltage for described driving transistor, and described method includes:

Monitor the content of the selection section of described display;

Described supply voltage is set as described display described selection section Current Content needed for minimum power source voltage; And

Judge that whether the quantity of the pixel needing the supply voltage bigger than set value in described selection section is more than reservation threshold quantity, and make described supply voltage reduce predetermined step-size amounts when answering as negative.

2. the step of the content the method for claim 1, wherein monitoring the described selection section of described display includes: monitoring is provided to the voltage of the grid input of described driving transistor input.

3. an active matrix organic light-emitting device display, comprising:

Adjustable source voltage source; With

Multiple pixels, each described pixel is connected to described adjustable source voltage source, and each described pixel includes:

Organic luminescent device;

There is the driving transistor of source electrode and drain electrode, described source electrode and the one in described drain electrode and be connected to described organic luminescent device and another one is connected to described adjustable source voltage source;

Multiple program voltages input, and they are connected to the grid of the described driving transistor of the plurality of pixel the program voltage of the expectation brightness of each pixel being provided for indicate that in the plurality of pixel; And

Supply voltage controller, it is connected to described adjustable voltage source, and to adjust the level of the supply voltage being provided to each described driving transistor, described supply voltage controller is used for:

Monitor the content of the selection section of described display;

When the quantity of the pixel needing the supply voltage bigger than set value in described selection section is more than reservation threshold quantity, described supply voltage is made to reduce predetermined step-size amounts.

4. active matrix organic light-emitting device display as claimed in claim 3, wherein, by monitoring the content that the voltage of the grid input being provided to the input of described driving transistor monitors the described selection section of described display.