WO2016107363A1 - 像素电路及其驱动方法和有源矩阵有机发光显示装置 - Google Patents

像素电路及其驱动方法和有源矩阵有机发光显示装置 Download PDF

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WO2016107363A1
WO2016107363A1 PCT/CN2015/096080 CN2015096080W WO2016107363A1 WO 2016107363 A1 WO2016107363 A1 WO 2016107363A1 CN 2015096080 W CN2015096080 W CN 2015096080W WO 2016107363 A1 WO2016107363 A1 WO 2016107363A1
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Prior art keywords
thin film
film transistor
organic light
node
power source
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PCT/CN2015/096080
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English (en)
French (fr)
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张九占
朱修剑
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昆山国显光电有限公司
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Priority to EP15875041.4A priority Critical patent/EP3242287B1/en
Priority to JP2017534787A priority patent/JP6435415B2/ja
Priority to US15/539,502 priority patent/US10354596B2/en
Priority to KR1020177020195A priority patent/KR101932744B1/ko
Publication of WO2016107363A1 publication Critical patent/WO2016107363A1/zh

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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]
    • G09G3/3275—Details of drivers for data electrodes
    • G09G3/3291—Details of drivers for data electrodes in which the data driver supplies a variable data voltage for setting the current through, or the voltage across, the light-emitting 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
    • 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]
    • G09G3/3225—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] using an active matrix
    • G09G3/3233—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] using an active matrix with pixel circuitry controlling the current through the light-emitting 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
    • 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]
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2300/00—Aspects of the constitution of display devices
    • G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
    • G09G2300/0809—Several active elements per pixel in active matrix panels
    • G09G2300/0819—Several active elements per pixel in active matrix panels used for counteracting undesired variations, e.g. feedback or autozeroing
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2300/00—Aspects of the constitution of display devices
    • G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
    • G09G2300/0809—Several active elements per pixel in active matrix panels
    • G09G2300/0842—Several active elements per pixel in active matrix panels forming a memory circuit, e.g. a dynamic memory with one capacitor
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2300/00—Aspects of the constitution of display devices
    • G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
    • G09G2300/0809—Several active elements per pixel in active matrix panels
    • G09G2300/0842—Several active elements per pixel in active matrix panels forming a memory circuit, e.g. a dynamic memory with one capacitor
    • G09G2300/0852—Several active elements per pixel in active matrix panels forming a memory circuit, e.g. a dynamic memory with one capacitor being a dynamic memory with more than one capacitor
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2300/00—Aspects of the constitution of display devices
    • G09G2300/08—Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
    • G09G2300/0809—Several active elements per pixel in active matrix panels
    • G09G2300/0842—Several active elements per pixel in active matrix panels forming a memory circuit, e.g. a dynamic memory with one capacitor
    • G09G2300/0861—Several active elements per pixel in active matrix panels forming a memory circuit, e.g. a dynamic memory with one capacitor with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
    • 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
    • G09G2320/0233—Improving the luminance or brightness uniformity across the screen
    • 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

Definitions

  • the present invention relates to the field of flat panel display technologies, and in particular, to a pixel circuit, a driving method thereof, and an active matrix organic light emitting display device.
  • the organic light emitting display device uses an organic light emitting diode (English name) to display an image, and is an active light emitting display device.
  • the display mode is the same as that of a conventional thin film transistor liquid crystal display device (English name: Thin Film Transistor liquid crystal) Display, referred to as TFT-LCD, has different display modes, no backlight, and has many advantages such as high contrast, fast response, and thinness. Therefore, the organic light emitting display device is known as a new generation of display device which can replace the thin film transistor liquid crystal display device.
  • the organic light emitting display device is divided into a passive matrix organic light emitting display device (English name: Passive Matrix Organic Light Emitting Display, referred to as PMOLED) and an active matrix organic light emitting display device (English full name Active Matrix Organic Light Emitting Display, referred to as AMOLED).
  • PMOLED Passive Matrix Organic Light Emitting Display
  • AMOLED Active Matrix Organic Light Emitting Display
  • the active matrix organic light emitting display device is also referred to as an active matrix organic light emitting display device.
  • the active matrix organic light emitting display device includes a scan line, a data line, and a pixel array defined by the scan line and the data line, each pixel of the pixel array includes an organic light emitting diode and is used for driving the organic light emitting diode Pixel circuit.
  • FIG. 1 is a pixel circuit diagram of a prior art active matrix organic light emitting display device.
  • the conventional pixel circuit 10 generally includes a switching thin film transistor T1, a driving thin film transistor T2, and a storage capacitor Cs.
  • the switching transistor T1 is connected to the scanning line S(n) and opened through the scanning line S(n).
  • the driving transistor T2 When the transistor T1 is switched, the data voltage V data supplied from the data line is stored to the storage capacitor Cs via the switching transistor T1, thereby controlling the driving transistor T2 to generate a current to drive the organic light emitting diode to emit light.
  • the brightness of the pixel is determined by the current flowing through the organic light emitting diode, and the current flowing through the organic light emitting diode is controlled by the pixel circuit.
  • a current flowing through the organic light emitting diode is affected by a threshold voltage of the driving transistor and a power supply voltage VDD applied to the pixel circuit, and when the threshold voltage of the driving transistor and the power supply voltage VDD change, the current flows.
  • VDD power supply voltage
  • a large change occurs in the current through the organic light emitting diode, resulting in the organic light emitting diode OLED still emitting light of different brightness for the data signal of the same brightness. Therefore, the conventional active matrix organic light emitting display device is difficult to display an image having uniform brightness.
  • An object of the present invention is to provide a pixel circuit, a driving method thereof and an active matrix organic light emitting display device, which solve the problem that the existing active matrix organic light emitting display device has poor brightness uniformity.
  • the present invention provides a pixel circuit including:
  • a first thin film transistor connected between the second node and the anode of the organic light emitting diode, the gate of which is connected to the first node;
  • a second thin film transistor connected between the first node and the third node, the gate of which is connected to the emission control line;
  • a third thin film transistor connected between the third node and the third power source, the gate of which is connected to the initialization control line;
  • a fourth thin film transistor connected between the first power source and the second node, the gate of which is connected to the scan line;
  • a fifth thin film transistor connected between the data line and the first node, the gate of which is connected to the scan line;
  • a sixth thin film transistor connected between the first power source and the second node, the gate of which is connected to the emission control line;
  • a seventh thin film transistor connected between the third power source and the anode of the organic light emitting diode, the gate of which is connected to the initialization control line;
  • the second capacitor is connected between the third node and the second node.
  • the cathode of the organic light emitting diode is connected to a second power source, the first power source and the second power source are used as a driving power source of the organic light emitting diode, and the third power source is used to provide an initialization voltage.
  • the initialization voltage is a negative voltage.
  • the first to seventh thin film transistors are all P-type thin film transistors.
  • the current supplied by the first thin film transistor to the organic light emitting diode is determined by a data voltage provided by the data line and an initialization voltage provided by a third power source, and provided by the first power source and the second power source
  • the power supply voltage is independent of the threshold voltage of the first thin film transistor.
  • the fourth thin film transistor and the fifth thin film transistor are controlled by a scan line
  • the third thin film transistor and the seventh thin film transistor are controlled by an initialization control line
  • the second thin film transistor and the sixth thin film transistor are emitted by Control line control.
  • the present invention further provides a driving method of a pixel circuit, wherein the driving method of the pixel circuit includes: the scanning period includes a first time period, a second time period, and a third time period, wherein
  • the scan signal provided by the scan line and the control signal provided by the initialization control line are changed from a high level to a low level, and a control signal provided by the emission control line is changed from a low level to a high level.
  • the control signal provided by the initialization control line is kept at a low level
  • the control signal provided by the emission control line is kept at a high level
  • the scan signal provided by the scan line is changed from a low level to a high level
  • the fourth film is turned off.
  • the transistor and the fifth thin film transistor stop writing the data voltage while completing sampling of the threshold voltage of the first thin film transistor;
  • the scan signal provided by the scan line remains high
  • the control signal provided by the initialization control line changes from low level to high level
  • the control signal provided by the emission control line changes from high level to low level.
  • the third thin film transistor and the seventh thin film transistor are turned off while the second thin film transistor and the sixth thin film transistor are turned on, and the first thin film transistor outputs a current and drives the organic light emitting diode to emit light.
  • the first power source is connected to the second node through the fourth thin film transistor, and the voltage of the second node is equal to the voltage provided by the first power source.
  • the first capacitor is shorted, and a voltage difference between a gate and a source of the first thin film transistor is equal to a voltage stored by the second capacitor.
  • the present invention also provides an active matrix organic light emitting display device comprising the pixel circuit as described above.
  • the pixel circuit initializes an anode of the organic light emitting diode through the seventh thin film transistor, thereby slowing down the organic light emitting diode Aging, increasing the service life of the organic light emitting diode, and the current output by the first thin film transistor as the driving element is determined by the data voltage supplied by the data line and the initialization voltage provided by the third power source, and external
  • the power supply voltage and the threshold voltage of the first thin film transistor are independent, and thus can be avoided by thin
  • the luminance of the threshold voltage of the film transistor and the variation of the power supply voltage are uneven, and thus, the active-cathode organic light-emitting display device using the pixel circuit and the driving method thereof not only increases the service life but also improves the display quality.
  • FIG. 1 is a schematic structural view of a pixel circuit of a prior art active matrix organic light emitting display device
  • FIG. 2 is a schematic structural view of a pixel circuit of the present invention
  • FIG. 3 is a timing chart of a driving method of a pixel circuit of the present invention.
  • FIG. 4 is a schematic structural view of an active matrix organic light emitting display device of the present invention.
  • the pixel circuit 20 includes: a first thin film transistor M1 connected between the second node N2 and the anode of the organic light emitting diode OLED, whose gate is connected to the first node N1; and the second thin film transistor M2 Connected between the first node N1 and the third node N3, the gate thereof is connected to the emission control line EM n ; the third thin film transistor M3 is connected between the third node N3 and the third power source, and the gate thereof is connected Initializing control line Clk n ; fourth thin film transistor M4 connected between first power source and second node N2, gate connected to scan line S n ; fifth thin film transistor M5 connected to data line D m and first Between the nodes N1, the gate thereof is connected to the scan line S n ; the sixth thin film transistor M6 is connected between the first power source and the second node N2, the gate thereof is
  • the cathode of the organic light emitting diode OLED is connected to a second power source, and the pixel circuit 20 and the organic light emitting diode OLED receive a first power source, a second power source, and a third power source that are provided from the outside (for example, from a power source).
  • the first power source and the second power source are used as a driving power source of the organic light emitting diode OLED
  • the first power source is for providing a first power voltage VDD
  • the second power source is for providing a second power voltage VSS
  • the three power supplies are used to provide an initialization voltage V ref .
  • the first power source is typically a high level voltage source
  • the second power source and the third power source are typically low level voltage sources.
  • the initialization voltage V ref provided by the third power source is a negative voltage.
  • the pixel circuit 20 controls the fourth thin film transistor M4 and the fifth TFT M5 through the scan line S n, Clk n through the initialization control line controlling the third TFT M3 and M7 seventh thin film transistor, by transmitting
  • the control line EM n controls the second thin film transistor M2 and the sixth thin film transistor M6.
  • the fourth thin film transistor M4 and the fifth thin film transistor M5 are both turned on, and the data voltage V data supplied from the data line D m is supplied to the first via the fifth thin film transistor M5.
  • the node N1, the first power supply voltage VDD supplied from the first power source is applied to the second node N2 through the fourth thin film transistor M4.
  • the third thin film transistor M3 and the seventh thin film transistor M7 are both turned on, and the initialization voltage V ref supplied from the third power source passes through the third thin film transistor M3 and the seventh thin film.
  • the transistor M7 is supplied to the third node N3 and the anode of the organic light emitting diode OLED, respectively.
  • the second thin film transistor M2 and the sixth thin film transistor M6 are both turned on, so that the first thin film transistor M1 is turned on and supplies a driving current to the organic light emitting diode OLED.
  • the organic light emitting diode OLED emits light of a corresponding brightness according to the driving current, and displays an image normally.
  • the pixel circuit 20 is a 7T2C type circuit structure including 7 thin film transistors and 2 capacitors, and 7 thin film transistors are P-type thin film transistors.
  • the first TFT M1 as a driving transistor, a third transistor M3 and the seventh thin film transistor M7 controlled by the initialization control line Clk n, the initialization control line for controlling the initializing Clk n; fourth TFT M4 and five thin film transistor M5 is controlled by the scan line S n, the scan line S n to control the driving transistor to write the samples and the data voltage V data threshold voltage of the second thin film transistor M2, and a sixth TFT M6 are EM n are controlled by the emission control line, the emission control line EM n to control the organic light emitting diode OLED emits light.
  • the initialization voltage V ref provided by the third power source is applied to the anode of the organic light emitting diode OLED via the seventh thin film transistor M7, and the anode of the organic light emitting diode OLED can be initialized, thereby increasing the organic light emitting diode OLED and Driving the lifetime of the thin film transistor M1.
  • the current supplied to the organic light emitting diode OLED by the first thin film transistor M1 is determined by the data voltage V data provided by the data line D m and the initialization voltage V ref provided by the third power source, and is provided with the first power source and the second power source.
  • the power supply voltage is independent of the threshold voltage of the first thin film transistor M1. Therefore, the pixel circuit 20 can avoid luminance unevenness caused by the threshold voltage deviation of the thin film transistor and the power supply voltage variation, thereby improving the display quality of the display device.
  • the present invention also provides a driving method of a pixel circuit.
  • the driving method of the pixel circuit includes:
  • the scan period includes a first time period t1, a second time period t2, and a third time period t3;
  • the scan signal provided by the scan line S n and the control signal provided by the initialization control line Clk n are both changed from a high level to a low level, and the control signal provided by the emission control line EM n is changed from a low level.
  • the third thin film transistor M3, the fourth thin film transistor M4, the fifth thin film transistor M5, and the seventh thin film transistor M7 are turned on, and the data voltage V data supplied from the data line Dm is supplied to the first through the fifth thin film transistor M5.
  • Node N1 at the same time, respectively, the third node N3 and the anode of the organic light emitting diode OLED are initialized by a third power source;
  • the control signal provided by the initialization control line Clk n is kept at a low level
  • the control signal supplied from the emission control line EM n is kept at a high level
  • the scan signal supplied from the scan line S n is changed from a low level to a high level.
  • the scan signal provided by the scan line S n is kept at a high level
  • the control signal supplied from the initialization control line Clk n is changed from a low level to a high level
  • the control signal supplied from the emission control line EM n is high.
  • the level is changed to a low level
  • the third thin film transistor M3 and the seventh thin film transistor M7 are turned off
  • the second thin film transistor M2 and the sixth thin film transistor M6 are turned on
  • the first thin film transistor M1 outputs a current and drives the organic light emitting diode to emit light.
  • the data voltage V data provided by the data line Dm is written into the first node N1 via the fifth thin film transistor M5, and the voltage of the first node N1 is turned on.
  • V N1 is equal to V data .
  • the fourth thin film transistor M4 is turned on, the first power source is connected to the second node N2 through the fourth thin film transistor M4, and the voltage V N2 of the second node N2 is equal to VDD.
  • the third power source supplies the initialization voltage V ref to the anode of the organic light emitting diode OLED through the seventh thin film transistor M7 to initialize the anode of the organic light emitting diode OLED.
  • the third power source supplies the initialization voltage V ref to the third node N3 through the third thin film transistor M3 to initialize the third node N3.
  • the anode voltage of the organic light emitting diode OLED and the voltage V N3 of the third node N3 are both equal to V ref .
  • the data voltage V data provided by the data line Dm stops writing to the first node N1
  • the voltage V N1 of the first node N1 is equal to the data voltage V data due to
  • the fourth thin film transistor M4 is turned off, the voltage V N2 of the second node N2 is pulled down to V data +
  • the second capacitor C2 is connected between the third node N3 and the second node N2, the voltage stored by the second capacitor C2 is V data +
  • V th is the threshold voltage of the first thin film transistor M1.
  • the threshold voltage of the first thin film transistor M1 is stored in the second capacitor C2, thereby completing sampling of the threshold voltage of the first thin film transistor M1.
  • the third power source cannot supply the initialization voltage V ref to the anode of the organic light emitting diode OLED through the seventh thin film transistor M7, thereby stopping the organic light emission.
  • the second thin film transistor M2 is turned on, so that the first capacitor C1 is short-circuited. Therefore, the gate-source voltage V sg 1 of the first thin film transistor M1, that is, the voltage difference between the gate and the source of the first thin film transistor M1, is equal to the voltage stored by the second capacitor C2. Therefore, the calculation formula of the gate-source voltage V sg 1 of the first thin film transistor M1 is:
  • V sg 1 V data +
  • the sixth thin film transistor M6 since the sixth thin film transistor M6 is turned on, the first power supply voltage VDD provided by the first power source is transmitted to the first thin film transistor M1 via the sixth thin film transistor M6, and the first thin film transistor M1 is turned on, and the driving current is along A power source flows through the path of the sixth thin film transistor M6, the first thin film transistor M1, and the organic light emitting diode OLED to the second power source, causing the organic light emitting diode OLED to illuminate.
  • the pixels In the third time period t3, the pixels normally emit light to display an image.
  • the calculation formula of the current I on flowing through the organic light emitting diode OLED is:
  • K is the product of the electron mobility, the aspect ratio, and the capacitance per unit area of the thin film transistor.
  • the current flowing through the organic light emitting diode OLED has nothing to do with the power supply voltage and the threshold voltage of the first thin film transistor M1, only with the data voltage V data , the initialization voltage V ref , and the constant K related. Even if the power supply voltage or the threshold voltage variation of the first TFT M1 deviation are not the convection current I through the organic light emitting diode OLED on impact. Therefore, the pixel circuit 20 and the driving method thereof can completely avoid the luminance unevenness caused by the threshold voltage deviation and the power supply line impedance. At the same time, the lifetime of the organic light emitting diode OLED and the first thin film transistor M1 as a driving transistor can be increased.
  • the present invention also provides an active matrix organic light emitting display device.
  • the active matrix organic light emitting display device includes: a display unit 100, a scan driver 200, and a data driver 300.
  • the display unit 100 includes a plurality of pixels 110, and the plurality of pixels 110 distributed in a matrix form scan lines S1 to Sn and the data lines D 1 to D m crossing regions, each of the pixels 110 connected to the corresponding scan lines and data lines, the pixel circuit 20 described above, the pixel 110 includes.
  • the display unit 100 receives the first power source VDD and the second power source VSS that are supplied from the outside (for example, from a power source).
  • the first power source VDD and the second power source VSS are used as a high-level voltage source and a low-level voltage source, respectively.
  • the first power source VDD and the second power source VSS are used as driving power sources for the pixels 110.
  • the display unit 100 includes a plurality of pixels 110, and the plurality of pixels 110 are distributed in an array of m ⁇ n, where m is the number of columns of the pixels 110, n is the number of rows of the pixels 110, m ⁇ 1, n ⁇ 1.
  • Each pixel 110 is connected to a corresponding scan line and data line (each scan line is connected to a row of pixels 110 corresponding to the serial number thereof, each data line being connected to a column of pixels 110 corresponding to the serial number thereof).
  • the pixels 110 located in the i-th row and the j-th column are connected to the i-th scan line S i and the j-th data line D j .
  • Each of the scan lines is coupled to a scan driver 200 that generates a scan control signal corresponding to a scan control signal externally provided (e.g., provided from a timing control unit). Said scan control signal generated by the scanning controller 200 respectively to scan lines S 1 S n are sequentially supplied to each pixel 110.
  • Each data line is coupled to a data driver 300 that produces a data signal corresponding to data and data control signals externally provided (e.g., provided from a timing control unit). The data signals generated by data driver 300 is supplied to the respective pixels 110 via the data lines D 1 to D m in synchronization with the scan signal.
  • each pixel 110 is initialized while receiving the data signal supplied from the data line; during the second time period t2, the data signal stops writing and is completed.
  • the pixel circuit 20 Since the pixel 110 includes the pixel circuit 20 as described above, the pixel circuit 20 has both a threshold voltage compensation effect and the influence of the variation of the first power supply voltage VDD on the luminance even if the power supply voltage changes or the first thin film transistor M1 The deviation of the threshold voltage does not affect the current I on flowing through the organic light emitting diode OLED, thereby improving the brightness uniformity of the active matrix organic light emitting display device.
  • the pixel circuit and the driving method thereof and the active matrix organic light emitting display device provided by the present invention, the pixel circuit initializes an anode of the organic light emitting diode through the seventh thin film transistor, thereby slowing down the
  • the aging of the organic light emitting diode increases the service life of the organic light emitting diode, and the current output by the first thin film transistor as the driving element is determined by the data voltage supplied by the data line and the initialization voltage provided by the third power source, and Regardless of the external power supply voltage and the threshold voltage of the first thin film transistor, it is possible to avoid luminance unevenness caused by the threshold voltage deviation of the thin film transistor and the power supply voltage variation, whereby the pixel circuit and the driving method thereof are employed
  • the active-cathode organic light-emitting display device not only increases the service life but also improves the display quality.

Abstract

一种像素电路（20）及其驱动方法和有源矩阵有机发光显示装置。像素电路（20）通过第七薄膜晶体管（M7）对有机发光二极管（OLED）的阳极进行初始化，从而减缓有机发光二极管（OLED）的老化，增加有机发光二极管（OLED）的使用寿命。作为驱动元件的第一薄膜晶体管（M1）所输出的电流由数据线（Dm）提供的数据电压和第三电源提供的初始化电压（Vref）决定，而与外部的电源电压以及第一薄膜晶体管（M1）的阈值电压无关，因此能够避免由薄膜晶体管的阈值电压偏差和电源电压变化所造成的亮度不均。因此采用像素电路（20）及其驱动方法的有源矩有机发光显示装置不但增加了使用寿命，而且提高了显示质量。

Description

像素电路及其驱动方法和有源矩阵有机发光显示装置 技术领域
本发明涉及平板显示技术领域，特别涉及一种像素电路及其驱动方法和有源矩阵有机发光显示装置。
背景技术
有机发光显示装置利用有机发光二极管(英文全称Organic Light Emitting Diode，简称OLED)显示图像，是一种主动发光的显示装置，其显示方式与传统的薄膜晶体管液晶显示装置(英文全称Thin Film Transistor liquid crystal display，简称TFT-LCD)显示方式不同，无需背光灯，而且，具有对比度高、响应速度快、轻薄等诸多优点。因此，有机发光显示装置被誉为可以取代薄膜晶体管液晶显示装置的新一代的显示装置。
根据驱动方式的不同，有机发光显示装置分为被动矩阵有机发光显示装置(英文全称Passive Matrix Organic Light Emitting Display，简称PMOLED)和主动矩阵有机发光显示装置(英文全称Active Matrix Organic Light Emitting Display，简称AMOLED)，主动矩阵有机发光显示装置也称为有源矩阵有机发光显示装置。
有源矩阵有机发光显示装置包括扫描线、数据线以及所述扫描线和数据线所定义出的像素阵列，所述像素阵列的每个像素均包括有机发光二极管和用于驱动所述有机发光二极管的像素电路。请参考图1，其为现有技术的有源矩阵有机发光显示装置的像素电路图。如图1所示，现有的像素电路10通常包括开关薄膜晶体管T1、驱动薄膜晶体管T2和存储电容Cs，所述开关晶体管T1与扫描线S(n)连接，通过扫描线S(n)打开所述开关晶体管T1时，数据线提供的数据电压Vdata经由所述开关晶体管T1存储到 存储电容Cs，从而控制所述驱动晶体管T2产生电流，以驱动有机发光二极管发光。
像素的亮度是由流经有机发光二极管的电流决定的，而流经有机发光二极管的电流由像素电路控制。在传统的像素电路中，流经有机发光二极管的电流会受到驱动晶体管的阈值电压和施加到所述像素电路的电源电压VDD的影响，当驱动晶体管的阈值电压和电源电压VDD出现变化时，流经有机发光二极管的电流就会发生较大的变化，导致所述有机发光二极管OLED对于相同亮度的数据信号仍发射出不同亮度的光。因此，传统的有源矩阵有机发光显示装置很难显示具有均匀亮度的图像。
基此，如何解决现有的有源矩阵有机发光显示装置存在亮度均匀性差的问题，成了本领域技术人员亟待解决的一个技术问题。
发明内容
本发明的目的在于提供一种像素电路及其驱动方法和有源矩阵有机发光显示装置，以解决现有的有源矩阵有机发光显示装置存在亮度均匀性差的问题。
为解决上述问题，本发明提供一种像素电路，其包括：
第一薄膜晶体管，连接在第二节点与有机发光二极管的阳极之间，其栅极连接到第一节点；
第二薄膜晶体管，连接在第一节点与第三节点之间，其栅极连接到发射控制线；
第三薄膜晶体管，连接在第三节点与第三电源之间，其栅极接到初始化控制线；
第四薄膜晶体管，连接在第一电源与第二节点之间，其栅极连接到扫描线；
第五薄膜晶体管，连接在数据线与第一节点之间，其栅极连接到扫描线；
第六薄膜晶体管，连接在第一电源与第二节点之间，其栅极连接到发射控制线；
第七薄膜晶体管，连接在第三电源与有机发光二极管的阳极之间，其栅极连接到初始化控制线；
第一电容，连接在第一节点与第三节点之间；以及
第二电容，连接在第三节点与第二节点之间。
可选的，所述有机发光二极管的阴极与第二电源连接，所述第一电源和第二电源用作所述有机发光二极管的驱动电源，所述第三电源用于提供初始化电压。
可选的，所述初始化电压为负电压。
可选的，所述第一薄膜晶体管至第七薄膜晶体管均为P型薄膜晶体管。
可选的，所述第一薄膜晶体管提供至所述有机发光二极管的电流由所述数据线提供的数据电压和第三电源提供的初始化电压决定，而与所述第一电源和第二电源提供的电源电压以及所述第一薄膜晶体管的阈值电压无关。
可选的，所述第四薄膜晶体管和第五薄膜晶体管通过扫描线控制，所述第三薄膜晶体管和第七薄膜晶体管通过初始化控制线控制，所述第二薄膜晶体管和第六薄膜晶体管通过发射控制线控制。
相应的，本发明还提供了一种像素电路的驱动方法，所述像素电路的驱动方法包括：扫描周期包括第一时间段、第二时间段和第三时间段，其中，
在第一时间段，扫描线提供的扫描信号和初始化控制线提供的控制信号均由高电平变为低电平，发射控制线提供的控制信号由低电平变为高电 平，打开第三薄膜晶体管、第四薄膜晶体管、第五薄膜晶体管和第七薄膜晶体管，数据线提供的数据电压经由第五薄膜晶体管提供至第一节点，同时，通过第三电源分别对第三节点和所述有机发光二极管的阳极进行初始化；
在第二时间段，初始化控制线提供的控制信号保持低电平，发射控制线提供的控制信号保持高电平，扫描线提供的扫描信号由低电平变为高电平，关闭第四薄膜晶体管和第五薄膜晶体管，停止写入数据电压，同时完成对第一薄膜晶体管的阈值电压的采样；
在第三时间段，扫描线提供的扫描信号保持高电平，初始化控制线提供的控制信号由低电平变为高电平，发射控制线提供的控制信号由高电平变为低电平，关闭第三薄膜晶体管和第七薄膜晶体管，同时打开第二薄膜晶体管和第六薄膜晶体管，第一薄膜晶体管输出电流并驱动所述有机发光二极管发光。
可选的，在第一时间段，第一电源通过第四薄膜晶体管连接至第二节点，第二节点的电压等于第一电源提供的电压。
可选的，在第三时间段，第一电容被短接，第一薄膜晶体管的栅极和源极之间的电压差等于第二电容所储存的电压。
相应的，本发明还提供了一种有源矩阵有机发光显示装置，所述有源矩阵有机发光显示装置包括如上所述的像素电路。
在本发明提供的像素电路及其驱动方法和有源矩阵有机发光显示装置中，所述像素电路通过所述第七薄膜晶体管对所述有机发光二极管的阳极进行初始化，从而减缓所述有机发光二极管的老化，增加所述有机发光二极管的使用寿命，而且，作为驱动元件的第一薄膜晶体管所输出的电流由所述数据线提供的数据电压和第三电源提供的初始化电压决定，而与外部的电源电压以及所述第一薄膜晶体管的阈值电压无关，因此能够避免由薄 膜晶体管的阈值电压偏差和电源电压变化所造成的亮度不均，由此，采用所述像素电路及其驱动方法的有源矩有机发光显示装置不但增加了使用寿命，而且提高了显示质量。
附图说明
图1是现有技术的有源矩阵有机发光显示装置的像素电路的结构示意图；
图2是本发明像素电路的结构示意图；
图3是本发明像素电路的驱动方法的时序图；
图4是本发明有源矩阵有机发光显示装置的结构示意图。
具体实施方式
以下结合附图和具体实施例对本发明提出的一种像素电路及其驱动方法和有源矩阵有机发光显示装置作进一步详细说明。根据下面说明和权利要求书，本发明的优点和特征将更清楚。需说明的是，附图均采用非常简化的形式且均使用非精准的比例，仅用以方便、明晰地辅助说明本发明实施例的目的。
请参考图2，其为本发明实施例的像素电路的结构示意图。如图2所示，所述像素电路20包括：第一薄膜晶体管M1，连接在第二节点N2与有机发光二极管OLED的阳极之间，其栅极连接到第一节点N1；第二薄膜晶体管M2，连接在第一节点N1与第三节点N3之间，其栅极连接到发射控制线EMn；第三薄膜晶体管M3，连接在第三节点N3与第三电源之间，其栅极接到初始化控制线Clkn；第四薄膜晶体管M4，连接在第一电源与第二节点N2之间，其栅极连接到扫描线Sn；第五薄膜晶体管M5，连接在数据线Dm与第一节点N1之间，其栅极连接到扫描线Sn；第六薄膜晶体管M6，连接 在第一电源与第二节点N2之间，其栅极连接到发射控制线EMn；第七薄膜晶体管M7，连接在第三电源与有机发光二极管OLED的阳极之间，其栅极连接到初始化控制线Clkn；第一电容C1，连接在第一节点N1与第三节点N3之间；第二电容C2，连接在第三节点N3与第二节点N1之间。
具体的，所述有机发光二极管OLED的阴极与第二电源连接，所述像素电路20和有机发光二极管OLED接收从外部(例如，从电源)提供的第一电源，第二电源和第三电源。其中，所述第一电源和第二电源用作有机发光二极管OLED的驱动电源，所述第一电源用于提供第一电源电压VDD，所述第二电源用于提供第二电源电压VSS，第三电源用于提供初始化电压Vref。所述第一电源一般为高电平电压源，所述第二电源和第三电源一般为低电平电压源。本实施例中，所述第三电源提供的初始化电压Vref为负电压。
如图2所示，所述像素电路20通过扫描线Sn控制第四薄膜晶体管M4和第五薄膜晶体管M5，通过初始化控制线Clkn控制第三薄膜晶体管M3和第七薄膜晶体管M7，通过发射控制线EMn控制第二薄膜晶体管M2和第六薄膜晶体管M6。
当扫描线Sn提供的扫描信号跃迁到低电平时，第四薄膜晶体管M4和第五薄膜晶体管M5均导通，数据线Dm提供的数据电压Vdata经由第五薄膜晶体管M5提供至第一节点N1，第一电源提供的第一电源电压VDD通过第四薄膜晶体管M4施加到第二节点N2。
当初始化控制线Clkn提供的控制信号跃迁至低电平时，第三薄膜晶体管M3和第七薄膜晶体管M7均导通，第三电源提供的初始化电压Vref通过第三薄膜晶体管M3和第七薄膜晶体管M7分别提供给第三节点N3和所述有机发光二极管OLED的阳极。
当发射控制线EMn提供的控制信号跃迁至低电平时，第二薄膜晶体管M2和第六薄膜晶体管M6均导通，使得第一薄膜晶体管M1导通并向有机 发光二极管OLED提供驱动电流，所述有机发光二极管OLED根据所述驱动电流发出对应亮度的光，正常显示图像。
本实施例中，所述像素电路20是一种7T2C型电路结构，包括7个薄膜晶体管和2个电容，7个薄膜晶体管均为P型薄膜晶体管。其中，第一薄膜晶体管M1作为驱动晶体管，第三薄膜晶体管M3和第七薄膜晶体管M7均由初始化控制线Clkn控制，所述初始化控制线Clkn用于控制初始化；第四薄膜晶体管M4和第五薄膜晶体管M5均由扫描线Sn控制，所述扫描线Sn用于分别控制数据电压Vdata的写入和驱动晶体管的阈值电压的采样，第二薄膜晶体管M2和第六薄膜晶体管M6均由发射控制线EMn控制，所述发射控制线EMn用于控制所述有机发光二极管OLED发光。
所述第三电源提供的初始化电压Vref经由第七薄膜晶体管M7施加到所述有机发光二极管OLED的阳极，能够对所述有机发光二极管OLED的阳极进行初始化，从而增加所述有机发光二极管OLED和驱动薄膜晶体管M1的使用寿命。
而且，第一薄膜晶体管M1提供至所述有机发光二极管OLED的电流由数据线Dm提供的数据电压Vdata和第三电源提供的初始化电压Vref决定，而与第一电源和第二电源提供的电源电压以及第一薄膜晶体管M1的阈值电压无关。因此，采用所述像素电路20能够避免由薄膜晶体管的阈值电压偏差和电源电压变化所造成的亮度不均，进而提高显示装置的显示质量。
相应的，本发明还提供了一种像素电路的驱动方法。请结合参考图2和图3，所述像素电路的驱动方法包括：
扫描周期包括第一时间段t1、第二时间段t2和第三时间段t3；其中，
在第一时间段t1，扫描线Sn提供的扫描信号和初始化控制线Clkn提供的控制信号均由高电平变为低电平，发射控制线EMn提供的控制信号由低电平变为高电平，打开第三薄膜晶体管M3、第四薄膜晶体管M4、第五薄 膜晶体管M5和第七薄膜晶体管M7，数据线Dm提供的数据电压Vdata经由第五薄膜晶体管M5提供至第一节点N1，同时，通过第三电源分别对第三节点N3和所述有机发光二极管OLED的阳极进行初始化；
在第二时间段t2，初始化控制线Clkn提供的控制信号保持低电平，发射控制线EMn提供的控制信号保持高电平，扫描线Sn提供的扫描信号由低电平变为高电平，关闭第四薄膜晶体管M4和第五薄膜晶体管M5，停止写入数据电压Vdata，同时完成对第一薄膜晶体管M1的阈值电压的采样；
在第三时间段t3，扫描线Sn提供的扫描信号保持高电平，初始化控制线Clkn提供的控制信号由低电平变为高电平，发射控制线EMn提供的控制信号由高电平变为低电平，关闭第三薄膜晶体管M3和第七薄膜晶体管M7，同时打开第二薄膜晶体管M2和第六薄膜晶体管M6，第一薄膜晶体管M1输出电流并驱动所述有机发光二极管发光。
具体的，在第一时间段t1，由于第五薄膜晶体管M5导通，所述数据线Dm提供的数据电压Vdata经由第五薄膜晶体管M5写入第一节点N1，第一节点N1的电压VN1等于Vdata。由于第四薄膜晶体管M4导通，第一电源通过第四薄膜晶体管M4连接至第二节点N2，此时第二节点N2的电压VN2等于VDD。在此过程中，第三电源通过第七薄膜晶体管M7将初始化电压Vref提供至有机发光二极管OLED的阳极，对有机发光二极管OLED的阳极进行初始化。由此，减缓了有机发光二极管OLED器件的老化，增加了有机发光二极管OLED的使用寿命。与此同时，第三电源通过第三薄膜晶体管M3将初始化电压Vref提供至第三节点N3，对第三节点N3进行初始化。初始化之后，所述有机发光二极管OLED的阳极电压和第三节点N3的电压VN3均等于Vref。
在第二时间段t2，由于第五薄膜晶体管M5截止，数据线Dm提供的数据电压Vdata停止写入第一节点N1，此时第一节点N1的电压VN1等于数据 电压Vdata，由于第四薄膜晶体管M4截止，第二节点N2的电压VN2被拉低至Vdata+|Vth|，第三节点N3的电压VN3仍然等于Vref。由于第二电容C2连接在第三节点N3与第二节点N2之间，因此第二电容C2所储存的电压为Vdata+|Vth|-Vref。其中，Vth是第一薄膜晶体管M1的阈值电压。由此，第一薄膜晶体管M1的阈值电压存储在第二电容C2中，从而完成对第一薄膜晶体管M1的阈值电压的采样。
在第三时间段t3，由于第七薄膜晶体管M7截止，所述第三电源无法通过所述第七薄膜晶体管M7将初始化电压Vref提供至所述有机发光二极管OLED的阳极，从而停止对有机发光二极管OLED的阳极的初始化。与此同时，第二薄膜晶体管M2导通，使得第一电容C1被短接。因此，第一薄膜晶体管M1的栅源电压Vsg1即所述第一薄膜晶体管M1的栅极和源极之间的电压差，等于第二电容C2所储存的电压。因此，第一薄膜晶体管M1的栅源电压Vsg1的计算公式为：
Vsg1＝Vdata+|Vth|-Vref      公式1；
在此过程中，由于第六薄膜晶体管M6导通，第一电源提供的第一电源电压VDD经由第六薄膜晶体管M6传输至第一薄膜晶体管M1，第一薄膜晶体管M1导通，驱动电流沿第一电源经第六薄膜晶体管M6、第一薄膜晶体管M1和有机发光二极管OLED的路径流到第二电源，致使有机发光二极管OLED点亮发光。在第三时间段t3，像素正常发光显示图像。
而流过所述有机发光二极管OLED的电流Ion的计算公式为：
Ion＝K×(Vsg1-|Vth|)2      公式2；
其中，K为薄膜晶体管的电子迁移率、宽长比、单位面积电容三者之积。
根据公式1和公式2可得：
Ion＝K×(Vdata-Vref)2      公式3；
基于公式3的表达式可知，流过所述有机发光二极管OLED的电流与所述电源电压和第一薄膜晶体管M1的阈值电压都没有关系，只与数据电压Vdata、初始化电压Vref以及常数K有关。即使电源电压发生变化或第一薄膜晶体管M1的阈值电压出现偏差，都不会对流过所述有机发光二极管OLED的电流Ion造成影响。因此，采用所述像素电路20及其驱动方法能够完全避免因阈值电压偏差和电源走线阻抗而造成的亮度不均现象。同时，能够增加所述有机发光二极管OLED和作为驱动晶体管的第一薄膜晶体管M1的使用寿命。
相应的，本发明还提供了一种有源矩阵有机发光显示装置。请参考图4，如图4所示，所述有源矩阵有机发光显示装置包括：显示单元100、扫描驱动器200和数据驱动器300；所述显示单元100包括多个像素110，所述多个像素110以矩阵形式分布在扫描线S1至Sn以及数据线D1至Dm的交叉区域，每个像素110与对应的扫描线和数据线连接，所述像素110包括如上所述的像素电路20。
具体的，所述显示单元100接收从外部(例如，从电源)提供的第一电源VDD和第二电源VSS。第一电源VDD和第二电源VSS分别用作高电平电压源和低电平电压源。第一电源VDD和第二电源VSS用作像素110的驱动电源。
如图4所示，所述显示单元100包括多个像素110，所述多个像素110呈m×n的阵列分布，其中，m为像素110的列数，n为像素110的行数，m≥1，n≥1。每个像素110连接到对应的扫描线和数据线(每一扫描线连接到与之序号对应的一行像素110，每一数据线连接到与之序号对应的一列像素110)。例如，将位于第i行和第j列的像素110连接到第i扫描线Si以及第j数据线Dj。
其中，各扫描线均与扫描驱动器200连接，所述扫描驱动器200产生 与外部提供(例如，从定时控制单元提供)的扫描控制信号相应的扫描控制信号。所述扫描控制器200产生的扫描控制信号分别通过扫描线S1至Sn顺序地提供给各像素110。各数据线均与数据驱动器300连接，所述数据驱动器300产生与外部提供(例如，从定时控制单元提供)的数据和数据控制信号相应的数据信号。所述数据驱动器300产生的数据信号通过数据线D1至Dm与扫描信号同步地提供给各像素110。
请结合参考图3和图4，在第一时间段t1期间，每个像素110被初始化，同时接受从数据线提供的数据信号；在第二时间段t2期间，数据信号停止写入，并完成驱动晶体管阈值电压的采样；在第三时间段t3期间，所述像素110通过发射具有与数据信号相应的亮度光来显示图像。
由于所述像素110包括如上所述的像素电路20，像素电路20既具有阈值电压补偿效果，又能够避免第一电源电压VDD变化对亮度的影响，即使电源电压发生变化或第一薄膜晶体管M1的阈值电压出现偏差都不会对流过所述有机发光二极管OLED的电流Ion造成影响，从而提高了所述有源矩阵有机发光显示装置的亮度均匀性。
综上，在本发明提供的像素电路及其驱动方法和有源矩阵有机发光显示装置中，所述像素电路通过所述第七薄膜晶体管对所述有机发光二极管的阳极进行初始化，从而减缓所述有机发光二极管的老化，增加所述有机发光二极管的使用寿命，而且，作为驱动元件的第一薄膜晶体管所输出的电流由所述数据线提供的数据电压和第三电源提供的初始化电压决定，而与外部的电源电压以及所述第一薄膜晶体管的阈值电压无关，因此能够避免由薄膜晶体管的阈值电压偏差和电源电压变化所造成的亮度不均，由此，采用所述像素电路及其驱动方法的有源矩有机发光显示装置不但增加了使用寿命，而且提高了显示质量。
上述描述仅是对本发明较佳实施例的描述，并非对本发明范围的任何 限定，本发明领域的普通技术人员根据上述揭示内容做的任何变更、修饰，均属于权利要求书的保护范围。

Claims (10)

  1. 一种像素电路，其特征在于，包括：
    第一薄膜晶体管，连接在第二节点与有机发光二极管的阳极之间，其栅极连接到第一节点；
    第二薄膜晶体管，连接在第一节点与第三节点之间，其栅极连接到发射控制线；
    第三薄膜晶体管，连接在第三节点与第三电源之间，其栅极接到初始化控制线；
    第四薄膜晶体管，连接在第一电源与第二节点之间，其栅极连接到扫描线；
    第五薄膜晶体管，连接在数据线与第一节点之间，其栅极连接到扫描线；
    第六薄膜晶体管，连接在第一电源与第二节点之间，其栅极连接到发射控制线；
    第七薄膜晶体管，连接在第三电源与有机发光二极管的阳极之间，其栅极连接到初始化控制线；
    第一电容，连接在第一节点与第三节点之间；以及
    第二电容，连接在第三节点与第二节点之间。
  2. 如权利要求1所述的像素电路，其特征在于，所述有机发光二极管的阴极与第二电源连接，所述第一电源和第二电源用作所述有机发光二极管的驱动电源，所述第三电源用于提供初始化电压。
  3. 如权利要求2所述的像素电路，其特征在于，所述初始化电压为负电压。
  4. 如权利要求1所述的像素电路，其特征在于，所述第一薄膜晶体管 至第七薄膜晶体管均为P型薄膜晶体管。
  5. 如权利要求1所述的像素电路，其特征在于，所述第一薄膜晶体管提供至所述有机发光二极管的电流由所述数据线提供的数据电压和第三电源提供的初始化电压决定，而与所述第一电源和第二电源提供的电源电压以及所述第一薄膜晶体管的阈值电压无关。
  6. 如权利要求1所述的像素电路，其特征在于，所述第四薄膜晶体管和第五薄膜晶体管通过扫描线控制，所述第三薄膜晶体管和第七薄膜晶体管通过初始化控制线控制，所述第二薄膜晶体管和第六薄膜晶体管通过发射控制线控制。
  7. 一种如权利要求1至6中任一项所述的像素电路的驱动方法，其特征在于，扫描周期包括第一时间段、第二时间段和第三时间段，其中，
    在第一时间段，扫描线提供的扫描信号和初始化控制线提供的控制信号均由高电平变为低电平，发射控制线提供的控制信号由低电平变为高电平，打开第三薄膜晶体管、第四薄膜晶体管、第五薄膜晶体管和第七薄膜晶体管，数据线提供的数据电压经由第五薄膜晶体管提供至第一节点，同时，通过第三电源分别对第三节点和所述有机发光二极管的阳极进行初始化；
    在第二时间段，初始化控制线提供的控制信号保持低电平，发射控制线提供的控制信号保持高电平，扫描线提供的扫描信号由低电平变为高电平，关闭第四薄膜晶体管和第五薄膜晶体管，停止写入数据电压，同时完成对第一薄膜晶体管的阈值电压的采样；
    在第三时间段，扫描线提供的扫描信号保持高电平，初始化控制线提供的控制信号由低电平变为高电平，发射控制线提供的控制信号由高电平变为低电平，关闭第三薄膜晶体管和第七薄膜晶体管，同时打开第二薄膜晶体管和第六薄膜晶体管，第一薄膜晶体管输出电流并驱动所述有机发光 二极管发光。
  8. 如权利要求7所述的像素电路的驱动方法，其特征在于，在第一时间段，第一电源通过第四薄膜晶体管连接至第二节点，第二节点的电压等于第一电源提供的电压。
  9. 如权利要求7所述的像素电路的驱动方法，其特征在于，在第三时间段，第一电容被短接，第一薄膜晶体管的栅极和源极之间的电压差等于第二电容所储存的电压。
  10. 一种有源矩阵有机发光显示装置，其特征在于，包括：如权利要求1至6中任一项所述的像素电路。
PCT/CN2015/096080 2014-12-30 2015-12-01 像素电路及其驱动方法和有源矩阵有机发光显示装置 WO2016107363A1 (zh)

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KR20170098275A (ko) 2017-08-29
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TW201635265A (zh) 2016-10-01
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