CN105243992A - System and methods for extracting correlation curves for an organic light emitting device - Google Patents

System and methods for extracting correlation curves for an organic light emitting device Download PDF

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Publication number
CN105243992A
CN105243992A CN201510378716.XA CN201510378716A CN105243992A CN 105243992 A CN105243992 A CN 105243992A CN 201510378716 A CN201510378716 A CN 201510378716A CN 105243992 A CN105243992 A CN 105243992A
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pixel
semiconductor devices
stress condition
stress
curve
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CN105243992B (en
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戈尔拉玛瑞扎·恰吉
里基·依克·黑·奈根
尼诺·扎西洛维奇
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Ignis Innovation Inc
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Ignis Innovation Inc
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    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/22—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources
    • G09G3/30—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels
    • G09G3/32—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED]
    • G09G3/3208—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters using controlled light sources using electroluminescent panels semiconductive, e.g. using light-emitting diodes [LED] organic, e.g. using organic light-emitting diodes [OLED]
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0271—Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/0285—Improving the quality of display appearance using tables for spatial correction of display data
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/02—Improving the quality of display appearance
    • G09G2320/029—Improving the quality of display appearance by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/04—Maintaining the quality of display appearance
    • G09G2320/043—Preventing or counteracting the effects of ageing
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/04—Maintaining the quality of display appearance
    • G09G2320/043—Preventing or counteracting the effects of ageing
    • G09G2320/045—Compensation of drifts in the characteristics of light emitting or modulating elements
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2320/00—Control of display operating conditions
    • G09G2320/04—Maintaining the quality of display appearance
    • G09G2320/043—Preventing or counteracting the effects of ageing
    • G09G2320/048—Preventing or counteracting the effects of ageing using evaluation of the usage time
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2330/00—Aspects of power supply; Aspects of display protection and defect management
    • G09G2330/12—Test circuits or failure detection circuits included in a display system, as permanent part thereof
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2360/00—Aspects of the architecture of display systems
    • G09G2360/14—Detecting light within display terminals, e.g. using a single or a plurality of photosensors
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2360/00—Aspects of the architecture of display systems
    • G09G2360/14—Detecting light within display terminals, e.g. using a single or a plurality of photosensors
    • G09G2360/141—Detecting light within display terminals, e.g. using a single or a plurality of photosensors the light conveying information used for selecting or modulating the light emitting or modulating element
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2360/00—Aspects of the architecture of display systems
    • G09G2360/14—Detecting light within display terminals, e.g. using a single or a plurality of photosensors
    • G09G2360/145—Detecting light within display terminals, e.g. using a single or a plurality of photosensors the light originating from the display screen

Abstract

A system for compensating the input signals to arrays of pixels that include semiconductor devices that age differently under different ambient and stress conditions. The system creates a library of compensation curves for different stress conditions of the semiconductor devices; identifies the stress conditions for at least a selected one of the semiconductor devices based on the rate of change or absolute value of at least one parameter of at least the selected device; selects a compensation curve for the selected device based on the identified stress conditions; calculates compensation parameters for the selected device based on the selected compensation curve; and compensates an input signal for the selected device based on the calculated compensation parameters.

Description

Extract the system and method for the correlation curve of organic luminescent device
The cross reference of related application
This application claims the right of priority of the U.S. Patent application 14/322,443 submitted on July 2nd, 2014, here the full content of this earlier application is incorporated to by reference herein.
Technical field
The present invention relates generally to the display of the luminescent device using such as OLED and so on, and relates more specifically to the characteristic correlation curve that extracts in this class display under different stress condition to compensate the aging of luminescent device.
Background technology
Relative to conventional LCD device, active matrix organic light-emitting device (AMOLED) display provides lower power consumption, manufactures the advantage of dirigibility and refresh rate faster.Compared with conventional LCD device, in displayer, there is not backlight, this is because each pixel is made up of the OLED of independent luminous different colours.OLED is based on the galvanoluminescence provided by driving transistors.Driving transistors is thin film transistor (TFT) (TFT) normally.The size of the light produced in the power consumption of each pixel and this pixel has direct relation.
At the run duration of organic light emitting diode device, it suffers deterioration, and this causes the light output under steady current to reduce along with the time.OLED also suffers electricity deterioration, and this causes the electric current under constant bias voltage to reduce along with the time.These deteriorations be substantially by OLED execute alive size and duration and the relevant stress of the electric current that produces in this device thus causes.This kind of deterioration due to the environmental factor of the existence and so on of such as temperature, humidity or oxygenant contribution in time and mix.The rate of ageing of film transistor device also depends on environment and stress (being biased).Carry out calibration pixel for the pixel historical data previously for several times stored, to determine the aging effect in pixel, thus suitably can determine that pixel transistor and OLED's is aging.Therefore, accurate aging data is needed at the whole life period of display device.
In a kind of OLED display compensation technique, extract aging (and/or homogeneity) of pixel panel and it can be used as original or treated data to store in a lookup table.Then, compensating module uses the data that store to any skew of the electrical parameter and optical parametric that compensate OLED (such as, the skew of OLED working voltage and optical efficiency) and the electricity of backboard and optical parametric any skew (such as, the threshold voltage shift of TFT), the program voltage of each pixel is thus revised according to stored data and video content.Compensating module revises drive TFT biased through OLED to keep the mode of identical luminance level for each grey level according to making enough electric currents.In other words, the aging electricity that is aging with optics and TFT of electricity that suitable program voltage suitably counteracts OLED is deteriorated.
At the life period of display, monitored constantly by the metering circuit fed back based on electricity and extract the electrical parameter of backboard TFT and OLED.Further, the optics ageing parameter of OLED is estimated according to the electricity deterioration data of OLED.But the optics aging effect of OLED also depends on the stress condition in independent pixel, and change between pixel, so accurate compensation can not be guaranteed, unless determined the compensation being suitable for concrete stress level due to stress.
Therefore, for the stress condition on active pixel, need the characteristic correlation curve effectively extracting accurate optical parametric and electrical parameter for compensation aging effect and other effect.For the various stress conditions that active pixel may stand at the run duration of display, need that there is various characteristic correlation curve.For based on the pixel in the organic luminescent device of display, also need accurate bucking-out system.
Summary of the invention
According to an embodiment, provide a kind of system of input signal of the array for compensation pixel, the semiconductor devices that described pixel is differentially aging under being included in different environment and stress condition, described system is used for: for the different stress conditions of described semiconductor devices, creates compensated curve storehouse; Based on rate of change or the absolute value of at least one parameter of at least chosen semiconductor devices in described semiconductor devices, identify the stress condition of at least described chosen semiconductor devices; Based on identified stress condition, select the compensated curve of described chosen semiconductor devices; Based on selected compensated curve, calculate the compensating parameter of described chosen semiconductor devices; And based on calculated compensating parameter, compensate the input signal of described chosen semiconductor devices.
Selectively, based on the rate of change of the rate of change of at least one parameter of at least chosen semiconductor devices in described semiconductor devices or absolute value and at least one parameter of second half conductor device or comparing of absolute value stress condition can be identified.
In view of the detailed description of the various embodiments of carrying out with reference to accompanying drawing, it will be appreciated by one of skill in the art that each aspect of the present invention, wherein will provide the concise and to the point of these accompanying drawings below.
Accompanying drawing explanation
The present invention can be understood best by reference to the explanation carried out by reference to the accompanying drawings below.
Fig. 1 is the block diagram of the displayer system with compensatory control.
Fig. 2 is the circuit diagram of the one in the reference pixel for revising based on measurement data in Fig. 1 of characteristic correlation curve.
Fig. 3 is the curve map of the brightness sent from active pixel, and this curve map reflects the stress condition that can need the different varying levels in time compensated.
Fig. 4 is the curve map of different qualities correlation curve and uses predetermined stress condition to determine the curve map of the result of the technology compensated.
Fig. 5 determines the process flow diagram with the process of renewing speciality correlation curve based on the reference pixel group under predetermined stress condition.
Fig. 6 uses predetermined characteristic correlation curve to compensate the process flow diagram of the process of the program voltage of the active pixel on display.
Fig. 7 is the relevance curve of the change of OLED efficiency degradation and OLED voltage.
Fig. 8 is the curve map of OLED stress history and stress intensity.
Fig. 9 A is OLED change in voltage under different stress conditions and the curve map of time.
Fig. 9 B is OLED voltage changing rate under different stress conditions and the curve map of time.
Figure 10 is the curve map of OLED voltage changing rate under different stress conditions and OLED change in voltage.
Figure 11 is the process flow diagram extracting the process of OLED efficiency degradation according to the change of the OLED parameter of such as OLED voltage and so on.
Figure 12 is the OLED relevance curve of OLED electric signal and efficiency degradation.
Figure 13 is the process flow diagram of the process extracting relevance curve from test component.
Figure 14 is the process flow diagram of the process calculating relevance curve from storehouse.
Figure 15 A and 15B is the process flow diagram identifying the process of the stress condition of this device based on the rate of change of the parameter of device or another device or absolute value.
Figure 16 is the example of the IV characteristic of the OLED being subject to three kinds of different stress conditions.
Although the present invention is vulnerable to various amendment and alternative form, shows specific embodiment by the mode of example in the accompanying drawings and described in detail in this article.But, should be appreciated that the present invention is not intended to be limited to particular forms disclosed.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 that are defined by the following claims.
Embodiment
Fig. 1 is the electronic display system 100 with active matrix region or pel array 102, in this active matrix region or pel array 102, has the array of active pixel 104 with the deployment arrangements of row and column.For convenience of diagram, illustrate only two row and two row.Be outer peripheral areas 106 in the outside of active matrix region (pel array 102), in outer peripheral areas 106, be furnished with the peripheral circuit in region for driving and control pel array 102.Peripheral circuit comprises grid or address driver circuits 108, source electrode or data driving circuit 110, controller 112 and optional voltage source (such as, EL_Vdd) driver 114.Controller 112 control gate driver 108, source electrode driver 110 and voltage source driver 114.Under the control of controller 112, gate drivers 108 pairs of addresses or selection line SEL [i], SEL [i+1] etc. operate, and there is an address or select line in every a line of the pixel 104 wherein in pel array 102.Share in configuration in following pixel, grid or address driver circuits 108 can also select line GSEL [j] to the overall situation alternatively and right/GSEL [j] operates alternatively, the overall situation selects line GSEL [j] or/GSEL [j] to operate the multiple row (such as, every two row of pixel 104) in the pixel 104 in pel array 102.Under the control of controller 112, source driver circuit 110 pairs of voltage data line Vdata [k], Vdata [k+1] etc. operate, and there is a voltage data line in each row of the pixel 104 wherein in pel array 102.The each pixel of voltage data alignment 104 transports the voltage-programming information of the brightness for representing each luminescent device in pixel 104.Memory element (such as, capacitor) storage voltage programming information in each pixel 104, until luminous or drive cycle unlatching luminescent device.Under the control of controller 112, there is a voltage source line in every a line of the pixel 104 wherein in pel array 102 in optional voltage source driver 114 control voltage source (EL_Vdd) line.Controller 112 is also connected to storer 118, and storer 118 is for storing below by the various characteristic correlation curve of the pixel 104 of explanation and ageing parameter.Storer 118 can be the one in flash memory, SRAM, DRAM, their combination and/or other storer or more person.
Display system 100 can also comprise current source circuit, and this current source circuit provides fixed current on current offset line.In some configurations, reference current can be provided to current source circuit.In this kind of configuration, current source control part controls the sequential applying bias current on current offset line.Do not thering is provided in the configuration of reference current to current source circuit, current source address driver controls the sequential applying bias current on current offset line.
It is known that for each pixel 104 in display system 100, need to use the information for the brightness representing the luminescent device in this pixel 104 to come its programming.Frame definition comprises the time period in programming cycle or stage and driving or light period or stage, wherein in programming cycle or during the stage, use for representing that the program voltage of brightness is to each pixel of programming in display system 100, and at driving or light period or during the stage, each luminescent device in each pixel is unlocked with according to the Intensity LEDs corresponding with the program voltage be stored in memory element.Therefore, frame forms in many still images of complete motion picture shown on display system 100.There are at least two kinds for programming and driving the scheme of pixel: line by line or frame by frame.When programming line by line, one-row pixels is programmed, and this row pixel of front wheel driving of then next line pixel being programmed and drive.When programming frame by frame, first the pixel of all row in display system 100 being programmed, and driving all frames line by line.Any one scheme can adopt the of short duration vertical blanking time of not programming to pixel or driving in the beginning of each period or end.
The assembly being arranged in pel array 102 outside can outer peripheral areas 106 around laying out pixel array 102, and outer peripheral areas 106 and pel array 102 are arranged on identical physics substrate.These assemblies comprise gate drivers 108, source electrode driver 110 and optional voltage source control part 114.Alternately, some assemblies in outer peripheral areas can be arranged on the same substrate with pel array 102, and other arrangement of components is on different substrates, or all component in outer peripheral areas can be arranged on different substrates from pel array 102.Gate drivers 108, source electrode driver 110 form display driving circuit together with voltage source control part 114.Display driving circuit in some configuration can comprise gate drivers 108 and source electrode driver 110 but not comprise voltage source control part 114.
Display system 100 also comprises current source and reading circuit 120, current source and reading circuit 120 read from DOL Data Output Line VD [k], VD [k+1] etc. and export data, there is a DOL Data Output Line in each row of the active pixel 104 wherein in pel array 102.Optional parametric device (such as, reference pixel) 130 to be in groups fabricated in outer peripheral areas 106 and to be arranged on the edge being positioned at active pixel 104 outside of pel array 102.Reference pixel 130 can also receive input signal from controller 112, and data-signal can be outputted to current source and reading circuit 120.Reference pixel 130 comprises driving transistors and OLED, but whether for showing a part for the pel array 102 of image.Illustrated by inciting somebody to action below, the reference pixel 130 of different group is in different stress conditions via the different levels of current from current providing circuit 120.Be not a part for pel array 102 due to reference pixel 130 and therefore do not show image, therefore reference pixel 130 can be provided for representing the data of the aging effect under different stress condition.Although illustrate only the reference pixel 130 of a line and row in Fig. 1, should be appreciated that the reference pixel that can there is arbitrary number.Each reference pixel 130 in example illustrated in fig. 1 is manufactured into the optical sensor 132 adjacent to correspondence.Optical sensor 132 is for determining the luminance level sent by the reference pixel 130 of correspondence.Should be appreciated that parametric device (such as, reference pixel 130) can be independently device instead of be fabricated in there is active pixel 104 display on.
Fig. 2 shows an example of the drive circuit 200 for the exemplary reference pixel 130 of in Fig. 1.The drive circuit 200 of reference pixel 130 comprises driving transistors 202, organic luminescent device (OLED) 204, holding capacitor 206, selects transistor 208 and monitor transistor 210.Voltage source 212 is connected to driving transistors 202.As shown in Figure 2, in this example, driving transistors 202 is the thin film transistor (TFT)s manufactured by amorphous silicon.Select line 214 to be connected to and select transistor 208 to activate drive circuit 200.Program voltage is applied to driving transistors 202 by voltage-programming input line 216.The output of OLED204 and/or driving transistors 202 monitored by monitoring line 218.Select line 214 to be connected to and select transistor 208 and monitor transistor 210.At reading time durations, line 214 is selected to be driven high.Program voltage can be applied via program voltage input line 216.Monitoring voltage can be read from the monitoring line 218 be connected with monitor transistor 210.The signal selecting line 214 can be sent to concurrently with the pixel programming cycle.
Stress can be added with certain levels of current to reference pixel 130 by applying constant voltage to program voltage input line 216.As by described below, export permission within the working time of reference pixel 130 for applied stress condition determination electrology characteristic data based on the reference voltage being applied to program voltage input line 216 from the voltage that monitoring line 218 is measured.Alternately, monitoring line 218 and program voltage input line 216 can merge (that is, Data/Mon) into a line, to perform programming by this single line and to monitor this two kinds of functions.The output of optical sensor 132 allows within the working time of reference pixel 130 for stress condition determination optical characteristics data.
According to an exemplary embodiment, in display system 100 in FIG, based on the aging brightness regulating each pixel (or sub-pixel) of at least one pixel, to keep basic uniform display in mission life (such as, the 75000 hours) period of system.The non-limiting example comprising the display device of display system 100 comprises mobile phone, digital camera, personal digital assistant (PDA), computing machine, televisor, portable video player, GPS (GPS) etc.
Along with the OLED material of active pixel 104 is aging, increase for keeping the voltage needed for the steady current of the given level in OLED.In order to the electricity compensating OLED is aging, storer 118 store each active pixel for keeping the bucking voltage needed for steady current.It also has the data of characteristic correlation curve form for different stress condition storage, controller 112 uses these data to determine bucking voltage, with amendment for driving the program voltage of each OLED of active pixel 104, thus also compensated the aging brightness showing desired output level suitably of optics of OLED thus by the electric current increasing OLED.Especially, storer 118 stores multiple predefined characteristic correlation curve or function, the deterioration of the luminance efficiency of the OLED that these predefined characteristic correlation curves or function representation run under different predetermined stress conditions.Different predetermined stress conditions generally represents the dissimilar stress that active pixel 104 may suffer at pixel life period or service condition.Different stress conditions can comprise the mixing of the steady current demand of varying level from low to high, constant luminance demand from low to high or plural stress level.Such as, stress level can be stress level under certain electric current and can be stress level under another electric current in another number percent of time in certain number percent of time.Other stress level can be special (specialized) stress level, such as, for representing on display system 100 level of shown average stream video (averagestreamingvideo).At first, the benchmark electrology characteristic of the parametric device of such as reference pixel 130 and so under different stress condition and baseline optical characteristic are stored in storer 118.In this example, after manufacture parametric device, benchmark electrology characteristic and the baseline optical characteristic of this parametric device is measured immediately from this parametric device.
Each this kind of stress condition can be applied in the following way: keep the steady current in reference pixel 130 in a period of time to reference pixel (such as, reference pixel 130) in groups; Keep the constant luminance of reference pixel 130 in a period of time; And/or the brightness of electric current in reference pixel or reference pixel is changed in a period of time with different predeterminated levels and predetermined space.The electric current produced in reference pixel 130 or luminance level can be such as high level, low value and/or the mean value desired by application-specific of display system 100.Such as, the application of such as computer monitor and so on requires high level.Similarly, in reference pixel, the time period of generation current or luminance level can be depending on the application-specific of display system 100.
Being contemplated that to obtain identical aging effect under each predetermined stress condition, applying different predetermined stress conditions at the run duration of display system 100 to different reference pixels 130.In other words, the first predetermined stress condition is applied to first group of reference pixel, the second predetermined stress condition is applied to second group of reference pixel, etc.In this example, display system 100 has many group reference pixels 130, is added stress under the stress condition that in the scope of the low current value to high current value that are in pixel 16 of these reference pixels are different.Therefore, there is the reference pixel 130 of 16 different groups in this example.Certainly, can adopt the stress condition of greater or lesser quantity, this depends on the factor of desired accuracy, the physical space in outer peripheral areas 106, the amount of available processing power and the amount and so on for the storer of storage characteristics correlation curve data such as compensated.
By making reference pixel or reference pixel group stand stress condition continuously, the assembly of reference pixel is aging according to the service condition of stress condition.When stress condition being applied to reference pixel at the run duration of system 100, the electrology characteristic of measurement and assessment reference pixel and optical characteristics, to obtain data for determining calibration curve, wherein these calibration curves are used for the aging of active pixel 104 in compensated array 102.In this example, for often organizing reference pixel 130, per hourly once measure optical characteristics and electrology characteristic.Therefore, for the measurement characteristics of reference pixel 130, upgrade corresponding characteristic correlation curve.Certainly, can carry out these and measure within shorter time period or longer time period, this depends on the degree of accuracy desired by compensation of ageing.
Usually, the brightness of OLED204 has direct linear relationship with the electric current being applied to OLED204.The optical characteristics of OLED can be represented as:
L＝O*I
In this formula, brightness L is the result being multiplied by electric current I based on the coefficient O of the characteristic of OLED.Along with OLED204 is aging, coefficient O reduces, and therefore under constant current value, brightness reduces.Therefore, the brightness of measuring at a given current can be used for for the coefficient O determining specific OLED204 under predetermined stress condition at special time place by the aging characteristic variations caused.
The electrology characteristic measured represents the relation between the voltage being provided to driving transistors 202 and the electric current produced in OLED204 thus.Such as, the thin film transistor (TFT) of the monitor transistor 210 in voltage sensor or such as Fig. 2 and so on can be utilized to measure the change of the voltage needed for constant current level for realizing in the OLED of reference pixel.Required voltage generally along with OLED204 and driving transistors 202 aging and increase.Required voltage and output current have power and restrain relation, as shown by the following formula.
I＝k*(V-e) a
In this formula, electric current I is determined by the constant k be multiplied with the result that input voltage V deducts coefficient e, and wherein coefficient e represents the electrology characteristic of driving transistors 202.Therefore, the power that voltage and electric current I have a variable a restrains relation.Along with transistor 202 is aging, coefficient e increases, and thus, needs larger voltage to produce identical electric current.Therefore, the electric current measured from reference pixel may be used for the value of the coefficient e determining specific reference pixel for the stress condition being applied to reference pixel at special time.
As mentioned above, optical characteristics O represents in the brightness of the OLED204 of the reference pixel 130 in the Fig. 2 measured by optical sensor 132 and OLED204 between electric current relation.Measured electrology characteristic e represents the relation between applied voltage and consequent electric current.When stress condition is applied to reference pixel, the optical sensor by the optical sensor 132 in such as Fig. 1 and so on carrys out the change of the brightness of witness mark pixel 130 under constant current level relative to baseline optical characteristic.The change of electrology characteristic relative to benchmark electrology characteristic can be measured, to determine that electric current exports from monitoring line.At the run duration of display system 100, stress condition levels of current is applied to reference pixel 130 continuously.When expecting to measure, remove this stress condition electric current, and activate selection line 214.Apply reference voltage, and obtain consequent luminance level from the output of optical sensor 132, and measure output voltage from monitoring line 218.Thus obtained data and previous optical data and electrical data are compared, to determine for specific stress condition to be exported by the aging electric current caused and the change of brightness output, and upgrades the characteristic of the reference pixel under this stress condition.The performance data through upgrading is used to carry out renewing speciality correlation curve.
Then, by using the electrology characteristic and optical characteristics measured from reference pixel, for the characteristic correlation curve (or function) that predetermined stress condition is determined in time.For the given pixel run under this stress condition, characteristic correlation curve provide between the aging and optical degradation of the electricity of expection can quantitative relationship.More particularly, each point on characteristic correlation curve determines the correlativity between the optical characteristics of the OLED of the given pixel under locating this stress condition the preset time of measuring reference pixel 130 and electrology characteristic.Then, for active pixel 104 aging under the stress condition identical with the stress condition being applied to reference pixel 130, controller 112 can use this characteristic to determine suitable bucking voltage.In another example, can periodically from basic OLED measuring basis optical characteristics while the optical characteristics of the OLED of witness mark pixel.Basis OLED is not added stress or is added stress with known and controlled speed.This will eliminate any environmental impact with reference to OLED characteristic.
Due to manufacturing process well known by persons skilled in the art and other factors, each reference pixel 130 of display system 100 may not have uniform characteristic, and this causes different luminescent properties.In a kind of technology, the value of electrology characteristic by being obtained by reference pixel in groups under predetermined stress condition and the value of light characteristic are averaging.The better expression of stress condition on the impact of mean pixel obtains in the following way: add stress condition to reference pixel 130 in groups, and applies average (pollingaveraging) technology of poll to avoid defect, measurement noises and the other problem that may occur during adding stress condition to reference pixel.Such as, improper value (such as, due to the reference pixel of noise or inefficacy and the improper value determined) can be removed by equalization.This technology can have the predetermined luminance level and electrology characteristic that must be satisfied before those values are comprised in equalization.For the reference pixel under given applied stress condition, extra statistical regression technology can also be used to provide less weight to the electrical and optical properties value significantly different from other measured value.
In this example, each stress condition is applied to the reference pixel of different group.The optical characteristics of witness mark pixel and electrology characteristic, and adopt poll averaging and/or statistical regression technology to determine the different qualities correlation curve corresponding with each stress condition.Different characteristic correlation curves is stored in storer 118.Although this example uses parametric device to determine correlation curve, can according to such as determining correlation curve according to historical data or by the alternate manner of the predetermined mode of manufacturer and so on.
At the run duration of display system 100, the reference pixel 130 often organized can stand respective stress condition, and upgrades by controller 112 and be stored in characteristic correlation curve in storer 118 at first to reflect the data from obtaining with the reference pixel 130 that active pixel 104 stands identical external condition.Thus, the characteristic correlation curve of each active pixel 104 can be adjusted to the electrology characteristic of reference pixel 130 and the measurement of light characteristic based on the run duration at display system 100.Therefore, the electrology characteristic under each stress condition and light characteristic to be stored in storer 118 and at the run duration of display system 100, it to be upgraded.The storage of data can be piecewise linear model.In this example, this piecewise linear model has 16 coefficients, and these 16 coefficients are updated when the voltage of witness mark pixel 130 and light characteristic.Alternately, can by using linear regression or determining by storing data in the look-up table in storer 118 and upgrade curve.
The characteristic correlation curve producing and store under each possibility stress condition is unpractical, this is because will need a large amount of resources (such as, storer storage, processing power etc.).Disclosed display system 100 overcomes this restriction by following operation: the dispersion number determining and store the characteristic correlation curve under predetermined stress condition, and subsequently by using linear or nonlinear algorithm to combine those predefined characteristic correlation curves with the compensating factor of each pixel 104 of the specific service condition combining display system 100 according to each pixel.As mentioned above, in this example, there is the scope of 16 different predetermined stress conditions, and in storer 118, therefore store 16 different characteristic correlation curves.
For each pixel 104, display system 100 analyzes the stress condition being just applied to this pixel 104, and by use algorithm and based on panel pixel predefined characteristic correlation curve and measured electricity is aging determines compensating factor.Then, display system 100 provides voltage based on compensating factor to pixel.Therefore, the stress of specific pixel 104 determined by controller 112, and for the adjoint performance data that the stress condition of specific pixel 104 is determined immediate two predetermined stress conditions and obtained from the reference pixel 130 under the stress condition that these are predetermined.Therefore, the stress condition of active pixel 104 drops between low predetermined stress condition and high predetermined stress condition.
For the ease of open, the example of the following linear processes formula for combining characteristic correlation curve is described by two this predefined characteristic correlation curves; But, should be appreciated that the predefine characteristic correlation curve that can utilize other quantity any in the example technique for combined characteristic correlation curve.These two illustrative properties correlation curves comprise the first characteristic correlation curve determined for condition of high ground stress and the second characteristic correlation curve determined for low-stress.
Use the ability of different qualities correlation curve can provide accurate compensation to the active pixel 104 of the different stress condition of the predetermined stress condition stood from be applied to reference pixel 130 to different levels.Fig. 3 shows the curve map of the different stress conditions in time of active pixel 104, it illustrates the luminance level sent in time.During first time period, the brightness of active pixel is represented by trace 302, and trace 302 shows brightness at 300 and 500 nit (cd/cm 2) between.Therefore, the stress condition being applied to active pixel during trace 302 is relatively high.In the second time period, the brightness of active pixel is represented by trace 304, and trace 304 shows brightness between 300 and 100 nits.Therefore, the stress condition during trace 304 is lower than the stress condition of first time period, and the aging effect of pixel is during this period different from the aging effect under condition of high ground stress.In the 3rd time period, the brightness of active pixel is represented by trace 306, and trace 306 shows brightness between 100 and 0 nit.Stress condition during this period is lower than the stress condition of the second time period.In the 4th time period, the brightness of active pixel is represented by trace 308, and trace 308 shows returning to the higher stress condition based on the higher brightness between 400 and 500 nits.
For the concrete stress condition of each active pixel 104, the stress condition of the reference pixel 130 of limited quantity and the limited quantity of correspondence can require to use average or (movement) on average continuously.For each pixel, concrete stress condition can be mapped as the linear combination of the characteristic correlation curve from multiple reference pixel 130.Two characteristic combinations under predetermined stress condition can compensate accurately to all stress conditions appeared between these stress conditions.Such as, close characteristic correlation curve can be determined for the active pixel with the stress condition be between these two reference curves with reference to characteristic correlation curves for two under high and low-stress.Controller 112 uses weight moving average algorithm (weightedmovingaveragealgorithm) to combine and is stored in first and second in storer 118 with reference to characteristic correlation curve.Stress condition St (the t that active pixel was located in certain time i) can be represented as:
St(t i)＝(St(t i-1)*k avg+L(t i))/(k avg+1)
In this formula, St (t i-1) be stress condition at previous time place, k avgit is moving average constant.L (t i) be the measurement brightness that active pixel was located in this certain time, it can be determined by following formula:
L ( t i ) = L p e a k ( g ( t i ) g p e a k ) γ
In this formula, L peakit is the maximum brightness that the design of display system 100 is allowed.Variable g (t i) be measure time gray scale, g peakbe the highest gray-scale value (such as, 255) used, and γ is gamma constant.Use the weight moving average algorithm of the characteristic correlation curve of predetermined height and low-stress can via following formula to determine compensating factor K comp:
K comp＝K highf high(ΔI)+K lowf low(ΔI)
In this formula, f highfirst function corresponding with the characteristic correlation curve of high predetermined stress condition, and f lowsecond function corresponding with the characteristic correlation curve of low predetermined stress condition.Δ I is the change of the electric current under fixed voltage input in OLED, it illustrates the change (electricity deterioration) caused by aging effect of measuring at special time place.Should be appreciated that the change of electric current can be replaced by the changes delta V of the voltage under fixed current.K highthe weight variable of the characteristic correlation curve being assigned to condition of high ground stress, and K lowit is the weight of the characteristic correlation curve being assigned to low-stress.Weight variable K can be determined according to following formula highand K low:
K high＝St(t i)/L high
K low＝1-K high
Here, L highthe brightness relevant to condition of high ground stress.
Voltage in the active pixel that any time of run duration is located or the change of electric current represent electrology characteristic, and represent optical characteristics as the curent change of a part for the function of high or low stress condition.In this example, by the brightness under condition of high ground stress, peak brightness and average compensating factor (function of the difference between two characteristic correlation curves) K avgbe stored in storer 118, for the compensating factor determining each active pixel.Supplementary variable be stored in storer 118, supplementary variable includes but not limited to the gray-scale value (such as, gray-scale value 255) of the high-high brightness that display system 100 is allowed.In addition, can carry out to determine by rule of thumb mean compensation algorithm factor K according to the data obtained during stress condition is applied to reference pixel avg.
Thus, can adjust the optical degradation of any pixel 104 in display system 100 and electricity aging between relation, to avoid the error relevant from the difference (divergence) of the characteristic correlation curve caused by different stress conditions.The quantity of the characteristic correlation curve stored can also be minimized to following quantity, and this quantity guarantees that averaging is enough accurate for required compensation level.
Compensating factor K compmay be used for by regulating the program voltage of active pixel to compensate oled light efficiency aging.Another is for determining that for the stress condition on active pixel the technology of suitable compensating factor can be called as dynamic mobile average (dynamicmovingaveraging).Dynamic mobile averaging comprises: change moving average COEFFICIENT K at the life period of display system 100 avg, to compensate the difference between two characteristic correlation curves under different predetermined stress conditions, thus the distortion preventing display from exporting.Along with the OLED of active pixel is aging, the difference between two characteristic correlation curves under different stress condition increases.Therefore, K can be increased at the life period of display system 100 avg, with the sharply transition between two curves avoiding having the active pixel of the stress condition dropped between two predetermined stress conditions.Measured curent change Δ I can be used to regulate K avgvalue, to improve the performance of the algorithm for determining compensating factor.
At another for improving in the technology (being called as the moving average based on event) of the performance of compensation deals, after each ageing step, make system reset.This technology further increases the extraction of the characteristic correlation curve of the OLED to each active pixel 104.(or after user opens or closes display system 100) reset display system 100 after each ageing step.In this example, compensating factor K is determined by following formula comp:
K comp＝K comp_evt+K high(f high(ΔI)-f high(ΔI evt))+K low(f low(ΔI)-f low(ΔI evt))
In this formula, K comp_evtthe compensating factor calculated at previous time place, and Δ I evtit is the change at the OLED electric current of previous time durations under fixed voltage.Compensating as other determines technology, and the change of electric current can be replaced by the change of the OLED voltage under fixed current.
Fig. 4 shows the curve map 400 of the different qualities correlation curve based on different technologies.Curve map 400 compares the change of the change of optical compensation number percent and the voltage for generation of the OLED of the active pixel needed for given electric current.As shown in curve map 400, in larger change place for reflecting the voltage that active pixel is aging, heavily stressed predetermined properties correlation curve 402 departs from from low stress predetermined properties correlation curve 404.Point 406 in groups represents by moving average (movingaveraging) technology and the calibration curve of the current compensation for active pixel determined at different change in voltage places according to predetermined properties correlation curve 402 and 404.Along with the change for reflecting aging voltage increases, the transition of calibration curve 406 has sharply transition between low stress characteristic correlation curve 404 and heavily stressed characteristic correlation curve 402.Point 408 in groups represents the characteristic correlation curve determined by average (dynamicmovingaveraging) technology of dynamic mobile.Point 410 in groups represents the compensating factor by determining based on moving average (event-basedmovingaveraging) technology of event.Based on OLED characteristic, a kind of technology in above-mentioned technology can be used to improve compensation to OLED efficiency degradation.
As mentioned above, the electrology characteristic of first group of sampled pixel is measured.Such as, the electrology characteristic of each pixel in first group of sampled pixel can be measured by the thin film transistor (TFT) (TFT) be connected with each pixel.Alternately, such as, optical characteristics (such as, brightness) can be measured by the optical sensor arranged for each pixel in the sampled pixel of first group.The variable quantity required by brightness that can extract each pixel according to the drift of the voltage of more than one pixel.This can be realized by the series of computation of the correlativity between the brightness for determining to be provided to the luminescent material in the voltage of pixel or the drift of electric current and/or this pixel.
Can by the processing apparatus of the processing apparatus or other such devices and so on of the controller 112 in such as Fig. 1 perform above-mentioned for extraction property correlation curve with the aging method of the pixel in compensated array, for computing machine, the technician of software and network field it is understood that, can according to as described in this article and the instruction that illustrates and through the more than one general-purpose computing system of programming, microprocessor, digital signal processor, microcontroller, special IC (ASIC), programmable logic device (PLD) (PLD), field programmable logic device (FPLD), field programmable gate array (FPGA) etc. realizes above-mentioned processing apparatus easily.
In addition, plural computing system or device can replace any one in controller described herein.Therefore, as needs, the principle and advantage of the distributed treatment can also realize such as redundancy, copying etc. and so on, to increase robustness and the performance of controller described herein.
The operation of the exemplary characteristic correlation curve for compensating aging method can be performed by machine readable instructions.In these examples, machine readable instructions comprises the algorithm performed by such as lower device: (a) processor, (b) controller and/or (c) other suitable processing apparatus more than one.Algorithm may be implemented as such as flash memories, CD-ROM, floppy disk, hard drive, the software that the tangible medium of digital video (multi-usage) dish (DVD) and so on or other memory device store, but the person skilled in the art will easily understand, whole algorithm and/or its part alternately can perform and/or be implemented as in known manner firmware or specialized hardware (such as by the device except processor, it can by special IC (ASIC), programmable logic device (PLD) (PLD), field programmable logic device (FPLD), field programmable gate array (FPGA), discrete logics etc. are implemented).Such as, for compensating any one of the ingredient of the characteristic correlation curve of aging method or all can being implemented by software, hardware and/or firmware.In addition, some or all of described machine readable instructions can manually be implemented.
Fig. 5 is for determining the process flow diagram with the process of the characteristic correlation curve of refresh display system (display system 100 such as, in Fig. 1).Select stress condition, to be provided for the sufficient benchmark (500) associated the scope of the stress condition of active pixel.Then, for each stress condition selects one group of reference pixel (502).Then, at each stress condition place, pair reference pixel of each group corresponding with this stress condition adds stress, and the optical characteristics of Memory Reference and electrology characteristic (504).Measure with periodic intervals and record the luminance level (506) of each pixel in each group.Then, light characteristic (508) is determined by being averaging the brightness measured by each pixel in the pixel groups under each stress condition.Determine the electrology characteristic (510) of each pixel in every group.Determine the mean value of each pixel in group, to determine average electrology characteristic (512).Then, the characteristic correlation curve (514) under using the average luminous characteristics often organized and average electrology characteristic to upgrade corresponding predetermined stress condition.Once determine and upgrade correlation curve, controller can use the characteristic correlation curve through upgrading to compensate the aging effect of the active pixel standing different stress condition.
With reference to figure 6, show use if the suitable predetermined properties correlation curve for display system 100 obtained in process is in Figure 5 to determine the process flow diagram of the process of the compensating factor of the active pixel at given time place.The brightness (600) that source pixel sends is defined based on maximum brightness and program voltage.The stress condition (602) of specific active pixel is measured based on previous stress condition, determined brightness and the mean compensation algorithm factor.Suitable predetermined stress characteristic correlation curve (604) is read from storer.In this example, two characteristic correlation curves correspond to predetermined stress condition, and wherein, the measured stress condition of active pixel drops between these predetermined stress conditions.Then, controller 112 changes by using the curtage measured from active pixel and determines coefficient (606) according to each predetermined stress condition.Then, amended coefficient determined by controller, added to the program voltage (608) of active pixel with calculation compensation voltage.Determined stress condition is stored in memory (610).Then, controller 112 stores new compensating factor, and the compensating factor that then can this be adopted new during each frame period after witness mark pixel 130 is to revise the program voltage (612) of active pixel.
OLED efficiency degradation can be calculated based on the relevance curve (the relevance curve such as, in Fig. 7) between the change of OLED electricity and efficiency degradation.Here, detect the change of OLED electrical parameter, and use this value to come from the deterioration of curve extraction efficiency.Then, correspondingly pixel current can be regulated, to compensate deterioration.Significant challenge is, relevance curve is the function of stress condition.Therefore, in order to realize compensating more accurately, a kind of needs are exactly the impact considering different stress condition.In one approach, the stress condition of each pixel (pixel groups) is used to select among different relevance curves, to extract suitable loss in efficiency for each concrete situation.Now, by the multiple method for identified sign condition of description.
First, the stress history of each pixel (pixel groups) can be created.Simply, stress history can be the moving average of stress condition.In order to improve counting accuracy, the stress history of weighting can be used.Here, as in the example that describes in fig. 8, the impact of each stress can have the different weights based on stress intensity or cycle.Such as, in the selection of OLED relevance curve, the impact of low-intensity stress is little.Therefore, there is the curve of little weight under can being used in small intensity, such as, curve in Fig. 8.Sub sampling (sub-sampling) can also be used to carry out calculated stress history, to reduce memory transfer activity (memorytransferactivity).In one case, can suppose that stress history is low frequency in time.In this case, do not need to sample to the pixel condition of every frame.Content-based frame rate (contentframerate) sampling rate of different application can be revised.Here, in each image duration, only select a small amount of pixel to obtain the stress history of renewal.
In another case, can suppose that stress history is spatially low frequency.In this case, do not need to sample to all pixels.Here, use pixel subset to carry out calculated stress history, and interpolation technique then can be used to calculate the stress history of all pixels.
In another case, can the low sampling rate on the assembly time and low sampling rate spatially.
In some cases, the storer needed for stress history and computing module may not be comprised.Here, as illustrated in figures 9a and 9b, the rate of change of OLED electrical parameter can be used to extract stress condition.Fig. 9 A illustrate low, in and Δ V under condition of high ground stress oLEDover time, and 9B shows rate of change under identical stress condition and the correlativity of time.
As shown in Figure 10, the rate of change of electrical parameter can be used as the indicator of stress condition.Such as, as shown in Figure 10, for different stress condition, modeling can be carried out to the electrical parameter rate of change changed based on electrical parameter, or extract by experiment.Rate of change also can be used to extract stress condition based on measured change with comparing of electrical parameter rate of change.Here, the function using change and rate of change into electrical parameter to set up.Alternately, can applied stress condition, relevance curve and measured running parameter.
Figure 11 is the process flow diagram for compensating the process of OLED efficiency degradation based on the change of OLED electrical parameter and the measurement of rate of change.In this process, in step 1101, extract the change of OLED parameter (such as, OLED voltage), and then calculate the rate of change of OLED parameter in step 1102 based on the value previously extracted.Then, the change of step 1103 operation parameter and rate of change identify stress condition.Finally, step 1104 carrys out counting yield deterioration according to stress condition, measured parameter and relevance curve.
As depicted in fig. 12, OLED efficiency degradation can be compensated by using the relevance curve of OLED electricity change (curtage) and efficiency degradation.Due to process variations, relevance curve may change.In one embodiment, test OLED can be used in each display, and extract the curve of each display after the fabrication or during display operation.When less display, test OLED can be placed on substrate and to be used for extracting curve after the fabrication.
Figure 13 is for extracting the process flow diagram of the process of relevance curve after rolling off the production line, during display operation or in the two combination from test component.In this case, the curve extracted in the factory is stored, for compensation of ageing.During display operation, the excessive data of the measurement result based on the test component in display can be used to upgrade curve.But, because leaching process can holding time, so can experiment curv group in advance, and these curves be placed in routine library.Here, test component is aging with predetermined ageing level (usually high than general case), to extract some aging characteristics (and/or measuring their current-voltage-brightness IVL) within the short time period.After this, use the aging characteristics extracted from curve library, find the suitable curve with similar or close aging characteristics.
In fig. 13, the viewing area of being added to by test component in first step 1301 on substrate is inner or outside.Then, in step 1302, test component is measured to extract relevance curve.Calculate the relevance curve of the display on substrate based on measured curve in step 1303.Store the curve of each display in step 1304, and in step 1305, then use these curves to compensate display ages.Alternately, test component can be measured in step 1306 during display operation.Then, relevance curve is upgraded based on measured result in step 1307.Calculate curve in step 1308 if desired, and based on these curve compensation displays in step 1309.
Here is some examples of the process for finding suitable curve from storehouse:
(1) curve with immediate aging characteristics (and/or IVL characteristic) is selected.
(2) use in storehouse have with test sample book closer to characteristic sample and create the curve of display.Here, can weighted mean be used, in weighted mean, determine the weight of each curve based on the error between their aging characteristics.
(3) if the immediate curve group in storehouse and the error between test component are greater than predetermined threshold, then test component can be used to create new curve and they to be joined in storehouse.
Figure 14 is the process flow diagram of the process for solving the process variations between substrate or in substrate.The viewing area of being added to by test component in first step 1401 on substrate is inner or outside, or test component can be display self.Then in step 1402, the test component of predetermined ageing level is measured, to extract the IVL characteristic of aging characteristics and/or measurement test component.The sample group with the immediate aging or test characteristic with test component in relevance curve library is found in step 1403.Then, determine whether the error between IVL and/or aging characteristics is less than threshold value in step 1404.If answer is affirmative, then in step 1405, use the curve in storehouse to calculate the relevance curve of the display in substrate.If the answer in step 1404 is negative, then in step 1406, use test component to extract new relevance curve.Then, in step 1407, use these curves to calculate the relevance curve of the display in substrate, and in step 1408, these new curves are added in storehouse.
Semiconductor devices (such as, OLED) can be differentially aging under different stress conditions and environmental baseline (such as, temperature, brightness etc.).And device may be advanced to the aging condition being different from normal condition by some rare stress conditions.Such as, high stress condition may damage device (such as, affecting contact site or other layer) physically.In this case, the identification of compensated curve may need extra information, these extra information can from other device pixel (such as, transistor or sensor) according to the change of device property (such as, threshold voltage shift or mobility change) speed obtain, or by use many device parameters (multiple-deviceparameter) change to identify stress condition to obtain.When using other device, the speed (or absolute value) of the change of the speed of the change of the parameter of other device and/or the parameter of other device can be used to identify aging condition relative to the speed (or absolute value) of the change of the parameter of this device.Such as, at higher temperatures, TFT and OLED becomes faster, and therefore rate of change can be TFT or OLED aging time the indicator of temperature variation.
Figure 15 A and 15B shows based on the rate of change of at least one parameter of at least one device or absolute value or based on the rate of change of at least one parameter of at least one device or the rate of change of at least one parameter of other device of absolute value and at least one or the process flow diagram comparing to come the process of the stress condition of recognition means of absolute value.The stress condition that identifies is used to select the parameter of suitable compensated curve based on identified stress condition and/or extraction device.Use selected compensated curve to carry out the compensating parameter of calculating device, and carry out compensated input signal based on calculated compensating parameter.
In Figure 15 A, in first step 1501a, check rate of change or the absolute value of at least one parameter of at least one device (such as, OLED), and then in step 1502a, identify stress condition according to this rate of change or absolute value.Then, in step 1503a, carry out the suitable compensated curve of selector based on identified stress condition and/or extract the parameter of this device.In step 1504a, use selected compensated curve to calculate the compensating parameter of this device, and then in step 1505a, carry out compensated input signal based on calculated compensating parameter.
In Figure 15 B, in first step 1501b, compare the rate of change of at least one parameter of at least one device (such as, OLED) or the rate of change of at least one parameter of absolute value and at least one other device or absolute value.Then, in step 1502b, relatively identify stress condition according to this, and carry out the suitable compensated curve of selector based on identified stress condition in step 1503b, or extract the parameter of this device.In step 1504b, use selected compensated curve to calculate the compensating parameter of this device, and then in step 1505b, carry out compensated input signal based on calculated compensating parameter.
In another embodiment, can check that the rate of change of the different parameters of a device is to identify stress condition.Such as, in case of oleds, voltage (or electric current) skew under different current level (or voltage level) can identify stress condition.The example of the IV characteristic of the OLED that Figure 16 is OLED under three kinds of different conditions (that is, starting condition, be subject to stress or be subject to stress at 27 DEG C at 40 DEG C).Can find out, along with the change of stress condition, characteristic changes significantly.
Although illustrate and described specific embodiment of the present invention, aspect and application, but be to be understood that, the invention is not restricted to disclosed accurate configuration and layout in this application, and various amendment, change and change can become obvious according to the above description when not departing from the spirit and scope of the present invention as defined by the appended claims.

Claims (3)

1. for a method for the input signal of the array of compensation pixel, the semiconductor devices that described pixel is differentially aging under being included in different environment and stress condition, described method comprises:
For the different stress conditions of described semiconductor devices, create compensated curve storehouse;
Based on rate of change or the absolute value of at least one parameter of at least chosen semiconductor devices in described semiconductor devices, identify the stress condition of at least described chosen semiconductor devices;
Based on identified stress condition, select the compensated curve of described chosen semiconductor devices;
Based on selected compensated curve, calculate the compensating parameter of described chosen semiconductor devices; And
Based on calculated compensating parameter, compensate the input signal of described chosen semiconductor devices.
2. for a method for the input signal of the array of compensation pixel, the semiconductor devices that described pixel is differentially aging under being included in different environment and stress condition, described method comprises:
For the different stress conditions of described semiconductor devices, create compensated curve storehouse;
Based on rate of change or the absolute value of at least one parameter of at least chosen semiconductor devices in described semiconductor devices, identify the stress condition of at least described chosen semiconductor devices;
Extract the parameter being just subject to the described chosen semiconductor devices of described stress condition;
Based on identified stress condition and at least one in the parameter extracted, select the compensated curve of described chosen semiconductor devices;
Based on selected compensated curve, calculate the compensating parameter of described chosen semiconductor devices; And
Based on calculated compensating parameter, compensate the input signal of described chosen semiconductor devices.
3. for a method for the input signal of the array of compensation pixel, the semiconductor devices that described pixel is differentially aging under being included in different environment and stress condition, described method comprises:
For the different stress conditions of described semiconductor devices, create compensated curve storehouse;
Based on the rate of change of at least one parameter of at least chosen semiconductor devices in described semiconductor devices or absolute value and the rate of change of at least one parameter of second half conductor device or comparing of absolute value, identify the stress condition of at least described chosen semiconductor devices;
Based on identified stress condition, select the compensated curve of described chosen semiconductor devices;
Based on selected compensated curve, calculate the compensating parameter of described chosen semiconductor devices; And
Based on calculated compensating parameter, compensate the input signal of described chosen semiconductor devices.
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