CN110570820B - AMOLED display device and driving method thereof - Google Patents
AMOLED display device and driving method thereof Download PDFInfo
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- CN110570820B CN110570820B CN201910723263.8A CN201910723263A CN110570820B CN 110570820 B CN110570820 B CN 110570820B CN 201910723263 A CN201910723263 A CN 201910723263A CN 110570820 B CN110570820 B CN 110570820B
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- 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
- G09G3/3258—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 voltage across the light-emitting element
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Abstract
The invention provides an AMOLED display device and a driving method thereof. The AMOLED display device comprises a display pixel unit, a threshold voltage compensation unit electrically connected with the display pixel unit and a test pixel unit electrically connected with the threshold voltage compensation unit; the display pixel unit and the test pixel unit are used for receiving scanning signals and data signals and emitting light under the driving of the scanning signals and the data signals; the threshold voltage compensation unit is used for detecting the current flowing through the test pixel unit, comparing the current flowing through the test pixel unit with a preset standard current, and outputting a compensation signal to the display pixel unit according to a comparison result so as to perform threshold voltage compensation on the display pixel unit, so that the threshold voltage of the driving thin film transistor can be effectively compensated, the structure of a compensation circuit is simplified, the aperture ratio is improved, and the driving cost is reduced.
Description
Technical Field
The invention relates to the technical field of display, in particular to an AMOLED display device and a driving method thereof.
Background
An Organic Light Emitting Diode (OLED) Display device has many advantages of self-luminescence, low driving voltage, high luminous efficiency, short response time, high definition and contrast, a viewing angle of approximately 180 °, a wide temperature range, flexible Display, large-area full color Display, and the like, and is considered as a Display device with the most potential for development.
The OLED display device may be classified into two major categories, i.e., direct addressing and Thin Film Transistor (TFT) Matrix addressing, of a Passive Matrix OLED (PMOLED) and an Active Matrix OLED (AMOLED) according to a driving manner. The AMOLED has pixels arranged in an array, belongs to an active display type, has high luminous efficiency, and is generally used as a large-sized display device with high definition. The AMOLED is a current-driven device, and when a current flows through an organic light emitting diode, the organic light emitting diode emits light, and the luminance is determined by the current flowing through the organic light emitting diode itself. Most of the existing Integrated Circuits (ICs) only transmit voltage signals, so the pixel driving Circuit of the AMOLED needs to complete the task of converting the voltage signals into current signals. A conventional AMOLED pixel driving circuit is generally 2T1C, i.e. a structure of two thin film transistors plus one capacitor, which converts a voltage into a current.
As shown in fig. 1, the conventional 2T1C pixel driving circuit for an AMOLED includes a first thin film transistor T10, a second thin film transistor T20, a capacitor C10 and an organic light emitting diode D10, wherein the first thin film transistor T10 is a switching thin film transistor, the second thin film transistor T20 is a driving thin film transistor, and the capacitor C10 is a storage capacitor. Specifically, the Gate of the first thin film transistor T10 is connected to the scan signal Gate, the source is connected to the Data signal Data, and the drain is electrically connected to the Gate of the second thin film transistor T20; the source electrode of the second thin film transistor T20 is connected with a power supply voltage Vdd, and the drain electrode is electrically connected with the anode of the organic light emitting diode D10; the cathode of the organic light emitting diode D10 is grounded; one end of the capacitor C10 is grounded, and the other end is electrically connected to the gate of the second tft T20. When the AMOLED displays, the scan signal Gate controls the first thin film transistor T10 to be turned on, the Data signal Data enters the Gate of the second thin film transistor T20 and the capacitor C10 through the first thin film transistor T10, and then the first thin film transistor T10 is turned on, due to the storage effect of the capacitor C10, the Gate voltage of the second thin film transistor T20 can still keep the Data signal voltage, so that the second thin film transistor T20 is in a conducting state, and the driving current enters the organic light emitting diode D10 through the second thin film transistor T20 to drive the organic light emitting diode D10 to emit light.
The conventional 2T1C pixel driving circuit for AMOLED is sensitive to the threshold voltage shift of the driving thin film transistor, and the current flowing through the organic light emitting diode varies greatly along with the threshold voltage shift of the driving thin film transistor, which results in unstable light emission and uneven brightness of the organic light emitting diode, and greatly affects the display effect of the picture.
Disclosure of Invention
The invention aims to provide an AMOLED display device, which can effectively compensate the threshold voltage of a driving thin film transistor, simplify the structure of a compensation circuit, improve the aperture opening ratio and reduce the driving cost.
The invention also provides a driving method of the AMOLED display device, which can effectively compensate the threshold voltage of the driving thin film transistor, simplify the structure of the compensation circuit, improve the aperture ratio, and reduce the driving cost.
In order to achieve the above object, the present invention provides an AMOLED display device, including a display pixel unit, a threshold voltage compensation unit electrically connected to the display pixel unit, and a test pixel unit electrically connected to the threshold voltage compensation unit;
the display pixel unit and the test pixel unit are used for receiving scanning signals and data signals and emitting light under the driving of the scanning signals and the data signals;
the threshold voltage compensation unit is used for detecting the current flowing through the test pixel unit, comparing the current flowing through the test pixel unit with a preset standard current, and outputting a compensation signal to the display pixel unit according to the comparison result so as to perform threshold voltage compensation on the display pixel unit.
The display pixel unit includes: the display device comprises a first thin film transistor, a second thin film transistor, a first capacitor, a second capacitor and a display organic light emitting diode;
the grid electrode of the first thin film transistor receives a scanning signal, the source electrode of the first thin film transistor receives a data signal, and the drain electrode of the first thin film transistor is electrically connected with a first node;
the grid electrode of the second thin film transistor is electrically connected with the first node, the source electrode of the second thin film transistor is electrically connected with the anode of the display organic light-emitting diode, and the drain electrode of the second thin film transistor receives power supply voltage;
the first end of the first capacitor is electrically connected with the first node, and the second end of the first capacitor is grounded;
the first end of the second capacitor receives the compensation signal, and the second end of the second capacitor is electrically connected with the first node;
the anode of the display organic light emitting diode is grounded.
The test pixel unit includes: a third thin film transistor, a fourth thin film transistor, a third capacitor and a test organic light emitting diode;
the grid electrode of the third thin film transistor receives a scanning signal, the source electrode of the third thin film transistor receives a data signal, and the drain electrode of the third thin film transistor is electrically connected with the second node;
the grid electrode of the fourth thin film transistor is electrically connected with the second node, the source electrode of the fourth thin film transistor is electrically connected with the anode of the organic light emitting diode to be tested, and the drain electrode of the fourth thin film transistor receives power supply voltage;
the first end of the third capacitor is electrically connected with the second node, and the second end of the third capacitor is grounded;
the anode of the test organic light emitting diode is grounded.
The threshold voltage compensation unit is electrically connected with the source electrode of the fourth thin film transistor.
The display pixel unit is arranged in an effective display area of the AMOLED display device, and the threshold voltage compensation unit and the test pixel unit are arranged in a non-display area of the AMOLED display device surrounding the effective display area.
The invention discloses a driving method of an AMOLED display device, which comprises the following steps:
step S1, providing an AMOLED display device including a display pixel unit, a threshold voltage compensation unit electrically connected to the display pixel unit, and a test pixel unit electrically connected to the threshold voltage compensation unit;
step S2, inputting scan signals and data signals to the display pixel unit and the test pixel unit, and driving the display pixel unit and the test pixel unit to emit light;
step S3, the threshold voltage compensation unit detects the current flowing through the test pixel unit, compares the current flowing through the test pixel unit with a preset standard current, and outputs a compensation signal for compensating the threshold voltage of the display pixel unit according to the comparison result;
in step S4, the display pixel unit receives the compensation signal and completes the threshold voltage compensation by using the compensation signal.
In step S1, the display pixel unit includes: the display device comprises a first thin film transistor, a second thin film transistor, a first capacitor, a second capacitor and a display organic light emitting diode;
the grid electrode of the first thin film transistor receives a scanning signal, the source electrode of the first thin film transistor receives a data signal, and the drain electrode of the first thin film transistor is electrically connected with a first node;
the grid electrode of the second thin film transistor is electrically connected with the first node, the source electrode of the second thin film transistor is electrically connected with the anode of the display organic light-emitting diode, and the drain electrode of the second thin film transistor receives power supply voltage;
the first end of the first capacitor is electrically connected with the first node, and the second end of the first capacitor is grounded;
the first end of the second capacitor receives the compensation signal, and the second end of the second capacitor is electrically connected with the first node;
the anode of the display organic light emitting diode is grounded.
In step S1, the test pixel unit includes: a third thin film transistor, a fourth thin film transistor, a third capacitor and a test organic light emitting diode;
the grid electrode of the third thin film transistor receives a scanning signal, the source electrode of the third thin film transistor receives a data signal, and the drain electrode of the third thin film transistor is electrically connected with the second node;
the grid electrode of the fourth thin film transistor is electrically connected with the second node, the source electrode of the fourth thin film transistor is electrically connected with the anode of the organic light emitting diode to be tested, and the drain electrode of the fourth thin film transistor receives power supply voltage;
the first end of the third capacitor is electrically connected with the second node, and the second end of the third capacitor is grounded;
the anode of the test organic light emitting diode is grounded; the threshold voltage compensation unit is electrically connected with the source electrode of the fourth thin film transistor.
In step S2, the scan signal controls the first thin film transistor and the third thin film transistor to be turned on, the data signal charges the first capacitor and the third capacitor, so that the voltages of the first node and the second node are increased, the second thin film transistor and the fourth thin film transistor are turned on, and the organic light emitting diode and the test organic light emitting diode are displayed to start emitting light;
in step S3, the threshold voltage compensation unit detects a current flowing through the test pixel unit from the source of the fourth tft, compares the current flowing through the test pixel unit with a preset standard current, and outputs a compensation signal according to the comparison result;
in step S4, the first terminal of the second capacitor receives the compensation signal, so that the voltage of the first node continues to rise to compensate the threshold voltage shift of the second thin film transistor.
In step S1, the display pixel units are disposed in an effective display area of the AMOLED display device, and the threshold voltage compensation units and the test pixel units are disposed in a non-display area of the AMOLED display device surrounding the effective display area.
The invention has the beneficial effects that: the invention provides an AMOLED display device, which comprises a display pixel unit, a threshold voltage compensation unit electrically connected with the display pixel unit and a test pixel unit electrically connected with the threshold voltage compensation unit; the display pixel unit and the test pixel unit are used for receiving scanning signals and data signals and emitting light under the driving of the scanning signals and the data signals; the threshold voltage compensation unit is used for detecting the current flowing through the test pixel unit, comparing the current flowing through the test pixel unit with a preset standard current, outputting a compensation signal to the display pixel unit according to a comparison result, and performing threshold voltage compensation on the display pixel unit. The invention also provides a driving method of the AMOLED display device, which can effectively compensate the threshold voltage of the driving thin film transistor and simplify the structure of the compensation circuit, improve the aperture opening ratio and reduce the driving cost.
Drawings
For a better understanding of the nature and technical aspects of the present invention, reference should be made to the following detailed description of the invention, taken in conjunction with the accompanying drawings, which are provided for purposes of illustration and description and are not intended to limit the invention.
In the drawings, there is shown in the drawings,
fig. 1 is a circuit diagram of a conventional AMOLED pixel driving circuit;
FIG. 2 is a schematic diagram of an AMOLED display device according to the present invention;
FIG. 3 is a circuit diagram of a display pixel unit of the AMOLED display device according to the present invention;
FIG. 4 is a circuit diagram of a test pixel unit of the AMOLED display device according to the present invention;
FIG. 5 is a waveform diagram illustrating the operation of the AMOLED display device according to the present invention;
fig. 6 is a flowchart of a driving method of the AMOLED display device according to the present invention.
Detailed Description
To further illustrate the technical means and effects of the present invention, the following detailed description is given with reference to the preferred embodiments of the present invention and the accompanying drawings.
Referring to fig. 2 to 5, the present invention provides an AMOLED display device, including a display pixel unit 10, a threshold voltage compensation unit 20 electrically connected to the display pixel unit 10, and a test pixel unit 30 electrically connected to the threshold voltage compensation unit 20;
the display pixel unit 10 and the test pixel unit 30 are used for receiving the scan signal Gate and the Data signal Data, and emitting light under the driving of the scan signal Gate and the Data signal Data;
the threshold voltage compensation unit 20 is configured to detect a current flowing through the test pixel unit 30, compare the current flowing through the test pixel unit 30 with a preset standard current, and output a compensation signal ST to the display pixel unit 10 according to a comparison result, so as to perform threshold voltage compensation on the display pixel unit 10.
Specifically, as shown in fig. 3, in a preferred embodiment of the present invention, the display pixel unit 10 includes: a first thin film transistor T1, a second thin film transistor T2, a first capacitor C1, a second capacitor C2 and a display organic light emitting diode D1;
the Gate of the first thin film transistor T1 receives a scan signal Gate, the source receives a Data signal Data, and the drain is electrically connected to the first node a;
the gate of the second thin film transistor T2 is electrically connected to the first node a, the source is electrically connected to the anode of the display organic light emitting diode D1, and the drain receives a power voltage Vdd;
a first end of the first capacitor C1 is electrically connected to the first node a, and a second end is grounded;
a first end of the second capacitor C2 receives the compensation signal ST, and a second end is electrically connected to the first node a;
the anode of the display organic light emitting diode D1 is grounded.
Further, as shown in fig. 4, in a preferred embodiment of the present invention, the test pixel unit 30 includes: a third thin film transistor T3, a fourth thin film transistor T4, a third capacitor C3, and a test organic light emitting diode D2;
the Gate of the third thin film transistor T3 receives a scan signal Gate, the source receives a Data signal Data, and the drain is electrically connected to the second node B;
the gate of the fourth thin film transistor T4 is electrically connected to the second node B, the source is electrically connected to the anode of the testing organic light emitting diode D2, and the drain receives the power voltage Vdd;
a first end of the third capacitor C3 is electrically connected to the second node B, and a second end is grounded;
the anode of the test organic light emitting diode D2 was grounded.
It should be noted that the first thin film transistor T1, the second thin film transistor T2, the first capacitor C1 and the display organic light emitting diode D1 are respectively the same as the third thin film transistor T3, the fourth thin film transistor T4, the third capacitor C3 and the test organic light emitting diode D2 in electrical performance, so that the threshold voltage shift in the display pixel unit 10 can be reflected by the test pixel unit 30.
Specifically, the threshold voltage compensation unit 20 is electrically connected to the source of the fourth thin film transistor T4.
Specifically, the display pixel unit 10 is disposed in the effective display area 1 of the AMOLED display device, the threshold voltage compensation unit 20 and the test pixel unit 30 are disposed in the non-display area 2 of the AMOLED display device surrounding the effective display area 1, and the threshold voltage compensation of the display pixel unit 10 is completed by the cooperation of the test pixel unit 30 and the threshold voltage compensation unit 20, so that compared with a compensation circuit formed by adding a compensation TFT to the display pixel unit 10, the circuit structure of the display pixel unit 10 can be simplified, the aperture ratio and the driving cost of the display pixel unit 10 can be improved, and the display effect can be improved.
It should be noted that, as shown in fig. 5, the three operation processes of the AMOLED display device sequentially include: a first stage 100, a second stage 200, and a third stage 300;
in the first phase 100, the scan signal Gate controls the first thin film transistor T1 and the third thin film transistor T3 to be turned on, the Data signal Data charges the first capacitor C1 and the third capacitor C3, so that the voltages of the first node a and the second node B rise, the second thin film transistor T4 is turned on, and the display oled D1 and the test oled D2 start to emit light;
in the second phase 200, the threshold voltage compensation unit 20 detects the current flowing through the test pixel unit 30 from the source of the fourth thin film transistor T4, compares the current flowing through the test pixel unit 30 with a predetermined standard current, and outputs a compensation signal ST according to the comparison result;
in the third stage 300, the first terminal of the second capacitor C2 receives the compensation signal ST, such that the voltage at the first node a continues to rise to compensate for the threshold voltage shift of the second thin film transistor T2.
For example, when the threshold voltage compensation unit 20 determines that the shift amount of the threshold voltage of the second thin film transistor T2, which is a driving thin film transistor, is Δ Vth according to the comparison result of the current flowing through the test pixel unit 30 and the preset standard current, the voltage of the compensation signal ST output by the threshold voltage compensation unit 20 is:
where Δ V is a voltage of the compensation signal ST, C2 is a size of the first capacitor C2, C1 is a size of the first capacitor C1, Cgd1 is a parasitic capacitance between the gate and the drain of the first thin film transistor T1, Cgd2 is a parasitic capacitance between the gate and the drain of the second thin film transistor T2, and Cgs2 is a parasitic capacitance between the gate and the source of the second thin film transistor T2.
Further, as shown in fig. 2, the AMOLED display device further includes: the signal interface 60 is electrically connected to the power supply 60 and the time sequence controller 90, and receives an external Voltage signal and a Low-Voltage differential signaling (LVDS), inputs the Voltage signal to the power supply 60, and inputs the LVDS signal to the time sequence controller 90; the timing controller 90 is electrically connected to the power source 60, the signal interface 70, the source driver 50 and the gate driver 40, receives a power supply voltage from the power source 60, receives an LVDS signal from the signal interface 60, generates a Mini (Mini) LVDS signal to the source driver 50, and generates a clock signal to the gate driver 40; the gamma converter 80 is electrically connected to the power source 60 and the source driver 50, receives a common voltage from the power source 60, and generates a gamma voltage to the source driver 50; the source driver 50 is electrically connected to the power source 60, the display pixel unit 10 and the test pixel unit 30, and outputs Data signals Data to the display pixel unit 10 and the test pixel unit 30; the Gate driver 40 is electrically connected to the power source 60, the display pixel unit 10 and the test pixel unit 30, and outputs a scan signal Gate to the display pixel unit 10 and the test pixel unit 30.
Therefore, the invention carries out threshold voltage compensation by arranging the test pixel unit and the threshold voltage compensation unit, can effectively compensate the threshold voltage of the driving thin film transistor and simultaneously simplify the structure of the compensation circuit, improves the aperture opening ratio and reduces the driving cost.
Referring to fig. 6, the present invention further provides a driving method of an AMOLED display device, including the following steps:
step S1, an AMOLED display device is provided, which includes a display pixel unit 10, a threshold voltage compensation unit 20 electrically connected to the display pixel unit 10, and a test pixel unit 30 electrically connected to the threshold voltage compensation unit 20.
Specifically, as shown in fig. 3, in a preferred embodiment of the present invention, the display pixel unit 10 includes: a first thin film transistor T1, a second thin film transistor T2, a first capacitor C1, a second capacitor C2 and a display organic light emitting diode D1;
the Gate of the first thin film transistor T1 receives a scan signal Gate, the source receives a Data signal Data, and the drain is electrically connected to the first node a;
the gate of the second thin film transistor T2 is electrically connected to the first node a, the source is electrically connected to the anode of the display organic light emitting diode D1, and the drain receives a power voltage Vdd;
a first end of the first capacitor C1 is electrically connected to the first node a, and a second end is grounded;
a first end of the second capacitor C2 receives the compensation signal ST, and a second end is electrically connected to the first node a;
the anode of the display organic light emitting diode D1 is grounded.
Further, as shown in fig. 4, in a preferred embodiment of the present invention, the test pixel unit 30 includes: a third thin film transistor T3, a fourth thin film transistor T4, a third capacitor C3, and a test organic light emitting diode D2;
the Gate of the third thin film transistor T3 receives a scan signal Gate, the source receives a Data signal Data, and the drain is electrically connected to the second node B;
the gate of the fourth thin film transistor T4 is electrically connected to the second node B, the source is electrically connected to the anode of the testing organic light emitting diode D2, and the drain receives the power voltage Vdd;
a first end of the third capacitor C3 is electrically connected to the second node B, and a second end is grounded;
the anode of the test organic light emitting diode D2 was grounded.
It should be noted that the first thin film transistor T1, the second thin film transistor T2, the first capacitor C1 and the display organic light emitting diode D1 are respectively the same as the third thin film transistor T3, the fourth thin film transistor T4, the third capacitor C3 and the test organic light emitting diode D2 in electrical performance, so that the threshold voltage shift in the display pixel unit 10 can be reflected by the test pixel unit 30.
Specifically, the threshold voltage compensation unit 20 is electrically connected to the source of the fourth thin film transistor T4.
Specifically, the display pixel unit 10 is disposed in the effective display area 1 of the AMOLED display device, the threshold voltage compensation unit 20 and the test pixel unit 30 are disposed in the non-display area 2 of the AMOLED display device surrounding the effective display area 1, and the threshold voltage compensation of the display pixel unit 10 is completed by the cooperation of the test pixel unit 30 and the threshold voltage compensation unit 20, so that compared with a compensation circuit formed by adding a compensation TFT to the display pixel unit 10, the circuit structure of the display pixel unit 10 can be simplified, the aperture ratio and the driving cost of the display pixel unit 10 can be improved, and the display effect can be improved.
Further, as shown in fig. 2, the AMOLED display device further includes: the signal interface 60 is electrically connected to the power supply 60 and the time sequence controller 90, and receives an external Voltage signal and a Low-Voltage differential signaling (LVDS), inputs the Voltage signal to the power supply 60, and inputs the LVDS signal to the time sequence controller 90; the timing controller 90 is electrically connected to the power source 60, the signal interface 70, the source driver 50 and the gate driver 40, receives a power supply voltage from the power source 60, receives an LVDS signal from the signal interface 60, generates a Mini (Mini) LVDS signal to the source driver 50, and generates a clock signal to the gate driver 40; the gamma converter 80 is electrically connected to the power source 60 and the source driver 50, receives a common voltage from the power source 60, and generates a gamma voltage to the source driver 50; the source driver 50 is electrically connected to the power source 60, the display pixel unit 10 and the test pixel unit 30, and outputs Data signals Data to the display pixel unit 10 and the test pixel unit 30; the Gate driver 40 is electrically connected to the power source 60, the display pixel unit 10 and the test pixel unit 30, and outputs a scan signal Gate to the display pixel unit 10 and the test pixel unit 30.
In step S2, a scan signal Gate and a Data signal Data are input to the display pixel unit 10 and the test pixel unit 30, and the display pixel unit 10 and the test pixel unit 30 are driven to emit light.
Specifically, in the step S2, the scan signal Gate controls the first thin film transistor T1 and the third thin film transistor T3 to be turned on, the Data signal Data charges the first capacitor C1 and the third capacitor C3, so that the voltages of the first node a and the second node B rise, the second thin film transistor T4 is turned on, and the display oled D1 and the test oled D2 start to emit light.
Step S3, the threshold voltage compensation unit 20 detects the current flowing through the test pixel unit 30, compares the current flowing through the test pixel unit 30 with a preset standard current, and outputs a compensation signal ST for compensating the threshold voltage of the display pixel unit 10 according to the comparison result;
specifically, in the step S3, the threshold voltage compensation unit 20 detects a current flowing through the test pixel unit 30 from the source of the fourth tft T4, compares the current flowing through the test pixel unit 30 with a predetermined standard current, and outputs the compensation signal ST according to the comparison result.
For example, when the threshold voltage compensation unit 20 determines that the shift amount of the threshold voltage of the second thin film transistor T2, which is a driving thin film transistor, is Δ Vth according to the comparison result of the current flowing through the test pixel unit 30 and the preset standard current, the voltage of the compensation signal ST output by the threshold voltage compensation unit 20 is:
where Δ V is a voltage of the compensation signal ST, C2 is a size of the first capacitor C2, C1 is a size of the first capacitor C1, Cgd1 is a parasitic capacitance between the gate and the drain of the first thin film transistor T1, Cgd2 is a parasitic capacitance between the gate and the drain of the second thin film transistor T2, and Cgs2 is a parasitic capacitance between the gate and the source of the second thin film transistor T2.
In step S4, the display pixel unit 10 receives the compensation signal ST and performs threshold voltage compensation using the compensation signal ST.
Specifically, in the step S4, the first terminal of the second capacitor C2 receives the compensation signal ST, so that the voltage of the first node a continues to rise to compensate the threshold voltage shift of the second thin film transistor T2.
In summary, the present invention provides an AMOLED display device, including a display pixel unit, a threshold voltage compensation unit electrically connected to the display pixel unit, and a test pixel unit electrically connected to the threshold voltage compensation unit; the display pixel unit and the test pixel unit are used for receiving scanning signals and data signals and emitting light under the driving of the scanning signals and the data signals; the threshold voltage compensation unit is used for detecting the current flowing through the test pixel unit, comparing the current flowing through the test pixel unit with a preset standard current, outputting a compensation signal to the display pixel unit according to a comparison result, and performing threshold voltage compensation on the display pixel unit. The invention also provides a driving method of the AMOLED display device, which can effectively compensate the threshold voltage of the driving thin film transistor and simplify the structure of the compensation circuit, improve the aperture opening ratio and reduce the driving cost.
As described above, it will be apparent to those skilled in the art that other various changes and modifications may be made based on the technical solution and concept of the present invention, and all such changes and modifications are intended to fall within the scope of the appended claims.
Claims (8)
1. An AMOLED display device is characterized by comprising a display pixel unit (10), a threshold voltage compensation unit (20) electrically connected with the display pixel unit (10), and a test pixel unit (30) electrically connected with the threshold voltage compensation unit (20);
the display pixel unit (10) and the test pixel unit (30) are used for receiving a scanning signal (Gate) and a Data signal (Data) and emitting light under the driving of the scanning signal (Gate) and the Data signal (Data);
the threshold voltage compensation unit (20) is used for detecting the current flowing through the test pixel unit (30), comparing the current flowing through the test pixel unit (30) with a preset standard current, and outputting a compensation Signal (ST) to the display pixel unit (10) according to the comparison result so as to perform threshold voltage compensation on the display pixel unit (10);
the display pixel unit (10) comprises: a first thin film transistor (T1), a second thin film transistor (T2), a first capacitor (C1), a second capacitor (C2) and a display organic light emitting diode (D1);
the grid electrode of the first thin film transistor (T1) receives a scanning signal (Gate), the source electrode of the first thin film transistor receives a Data signal (Data), and the drain electrode of the first thin film transistor is electrically connected with a first node (A);
the grid electrode of the second thin film transistor (T2) is electrically connected with the first node (A), the source electrode of the second thin film transistor is electrically connected with the anode of the display organic light emitting diode (D1), and the drain electrode of the second thin film transistor receives power supply voltage (Vdd);
the first end of the first capacitor (C1) is electrically connected with the first node (A), and the second end is grounded;
a first end of the second capacitor (C2) receives the compensation Signal (ST), and a second end is electrically connected with the first node (A);
the anode of the display organic light emitting diode (D1) is grounded;
the threshold voltage compensation unit (20) determines the drift amount of the threshold voltage of the second thin film transistor (T2) to be delta Vth according to the comparison result of the current flowing through the test pixel unit (30) and the preset standard current, and the voltage of the compensation Signal (ST) output by the threshold voltage compensation unit (20) is as follows:
where Δ V is a voltage level of the compensation Signal (ST), C2 is a level of the second capacitor (C2), C1 is a level of the first capacitor (C1), Cgd1 is a parasitic capacitance between the gate and the drain of the first thin film transistor (T1), Cgd2 is a parasitic capacitance between the gate and the drain of the second thin film transistor (T2), and Cgs2 is a parasitic capacitance between the gate and the source of the second thin film transistor (T2).
2. An AMOLED display device as claimed in claim 1, wherein the test pixel cell (30) comprises: a third thin film transistor (T3), a fourth thin film transistor (T4), a third capacitor (C3) and a test organic light emitting diode (D2);
the grid electrode of the third thin film transistor (T3) receives a scanning signal (Gate), the source electrode of the third thin film transistor receives a Data signal (Data), and the drain electrode of the third thin film transistor is electrically connected with a second node (B);
the grid electrode of the fourth thin film transistor (T4) is electrically connected with the second node (B), the source electrode of the fourth thin film transistor is electrically connected with the anode of the testing organic light emitting diode (D2), and the drain electrode of the fourth thin film transistor receives power supply voltage (Vdd);
a first end of the third capacitor (C3) is electrically connected with the second node (B), and a second end is grounded;
the anode of the test organic light emitting diode (D2) is grounded.
3. An AMOLED display device as claimed in claim 2, wherein the threshold voltage compensation unit (20) is electrically connected to the source of the fourth thin film transistor (T4).
4. An AMOLED display device as claimed in claim 1, wherein the display pixel cells (10) are provided in an active display area (1) of the AMOLED display device, and the threshold voltage compensation unit (20) and the test pixel cells (30) are provided in a non-display area (2) of the AMOLED display device surrounding the active display area (1).
5. A driving method of an AMOLED display device is characterized by comprising the following steps:
step S1, providing an AMOLED display device including a display pixel unit (10), a threshold voltage compensation unit (20) electrically connected to the display pixel unit (10), and a test pixel unit (30) electrically connected to the threshold voltage compensation unit (20);
step S2, inputting a scan signal (Gate) and a Data signal (Data) to the display pixel unit (10) and the test pixel unit (30), and driving the display pixel unit (10) and the test pixel unit (30) to emit light;
step S3, the threshold voltage compensation unit (20) detects the current flowing through the test pixel unit (30), compares the current flowing through the test pixel unit (30) with a preset standard current, and outputs a compensation Signal (ST) for compensating the threshold voltage of the display pixel unit (10) according to the comparison result;
step S4, the display pixel unit (10) receives a compensation Signal (ST) and completes threshold voltage compensation by using the compensation Signal (ST);
in step S1, the display pixel unit (10) includes: a first thin film transistor (T1), a second thin film transistor (T2), a first capacitor (C1), a second capacitor (C2) and a display organic light emitting diode (D1);
the grid electrode of the first thin film transistor (T1) receives a scanning signal (Gate), the source electrode of the first thin film transistor receives a Data signal (Data), and the drain electrode of the first thin film transistor is electrically connected with a first node (A);
the grid electrode of the second thin film transistor (T2) is electrically connected with the first node (A), the source electrode of the second thin film transistor is electrically connected with the anode of the display organic light emitting diode (D1), and the drain electrode of the second thin film transistor receives power supply voltage (Vdd);
the first end of the first capacitor (C1) is electrically connected with the first node (A), and the second end is grounded;
a first end of the second capacitor (C2) receives the compensation Signal (ST), and a second end is electrically connected with the first node (A);
the anode of the display organic light emitting diode (D1) is grounded.
6. The method of driving an AMOLED display device as set forth in claim 5, wherein in step S1, the test pixel cell (30) includes: a third thin film transistor (T3), a fourth thin film transistor (T4), a third capacitor (C3) and a test organic light emitting diode (D2);
the grid electrode of the third thin film transistor (T3) receives a scanning signal (Gate), the source electrode of the third thin film transistor receives a Data signal (Data), and the drain electrode of the third thin film transistor is electrically connected with a second node (B);
the grid electrode of the fourth thin film transistor (T4) is electrically connected with the second node (B), the source electrode of the fourth thin film transistor is electrically connected with the anode of the testing organic light emitting diode (D2), and the drain electrode of the fourth thin film transistor receives power supply voltage (Vdd);
a first end of the third capacitor (C3) is electrically connected with the second node (B), and a second end is grounded;
the anode of the test organic light emitting diode (D2) is grounded; the threshold voltage compensation unit (20) is electrically connected to the source of the fourth thin film transistor (T4).
7. The method of driving an AMOLED display device as recited in claim 6,
in the step S2, the scan signal (Gate) controls the first thin film transistor (T1) and the third thin film transistor (T3) to be turned on, the Data signal (Data) charges the first capacitor (C1) and the third capacitor (C3), so that the voltages of the first node (a) and the second node (B) are increased, the second thin film transistor (T4) and the fourth thin film transistor (T4) are turned on, and the display organic light emitting diode (D1) and the test organic light emitting diode (D2) start to emit light;
in the step S3, the threshold voltage compensation unit (20) detects a current flowing through the test pixel unit (30) from the source of the fourth thin film transistor (T4), compares the current flowing through the test pixel unit (30) with a predetermined standard current, and outputs a compensation Signal (ST) according to the comparison result;
in the step S4, the first terminal of the second capacitor (C2) receives the compensation Signal (ST), so that the voltage of the first node (a) continues to rise to compensate the threshold voltage shift of the second thin film transistor (T2).
8. The method of driving an AMOLED display device as claimed in claim 6, wherein the display pixel cells (10) are disposed in an active display area (1) of the AMOLED display device, and the threshold voltage compensation unit (20) and the test pixel cells (30) are disposed in a non-display area (2) of the AMOLED display device surrounding the active display area (1) in step S1.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910723263.8A CN110570820B (en) | 2019-08-06 | 2019-08-06 | AMOLED display device and driving method thereof |
| PCT/CN2019/104222 WO2021022601A1 (en) | 2019-08-06 | 2019-09-03 | Amoled display apparatus and drive method therefor |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910723263.8A CN110570820B (en) | 2019-08-06 | 2019-08-06 | AMOLED display device and driving method thereof |
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| CN110570820B true CN110570820B (en) | 2020-10-16 |
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| CN111179842B (en) * | 2020-03-12 | 2021-03-30 | 京东方科技集团股份有限公司 | Compensation circuit, display module and driving method thereof |
| CN111627375B (en) * | 2020-05-29 | 2022-02-08 | 上海天马微电子有限公司 | Driving circuit, driving method thereof and display device |
| CN112599078B (en) * | 2020-12-17 | 2022-03-01 | 北京大学深圳研究生院 | Pixel unit and pixel external analog domain compensation display system |
| CN113487994B (en) * | 2021-06-16 | 2022-05-06 | 中国科学院微电子研究所 | Pixel circuit, display device and pixel compensation method |
| CN115331613A (en) * | 2022-08-15 | 2022-11-11 | 惠科股份有限公司 | Driving circuit, driving method and display device |
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| KR101448006B1 (en) * | 2008-02-14 | 2014-10-13 | 삼성디스플레이 주식회사 | Liquid crystal display |
| CN102222468A (en) * | 2011-06-23 | 2011-10-19 | 华南理工大学 | Alternating-current pixel driving circuit and method for active organic light-emitting diode (OLED) display |
| CN102654973B (en) * | 2011-08-15 | 2014-11-19 | 京东方科技集团股份有限公司 | Pixel circuit and drive method thereof as well as display panel |
| CN103681772B (en) * | 2013-12-27 | 2018-09-11 | 京东方科技集团股份有限公司 | A kind of array substrate and display device |
| KR20150141368A (en) * | 2014-06-10 | 2015-12-18 | 네오뷰코오롱 주식회사 | Apparatuse and method for compensation luminance difference of organic light-emitting display device |
| CN105243994B (en) * | 2015-11-11 | 2018-03-06 | 深圳市华星光电技术有限公司 | AMOLED drive systems and driving method |
| CN105280139B (en) * | 2015-11-11 | 2018-05-01 | 深圳市华星光电技术有限公司 | AMOLED luminance compensation methods and AMOLED drive systems |
| CN107068054A (en) * | 2017-04-25 | 2017-08-18 | 深圳市华星光电技术有限公司 | A kind of drive circuit and liquid crystal display |
| CN208271546U (en) * | 2018-05-14 | 2018-12-21 | 昆山国显光电有限公司 | Array substrate, display screen and display device |
| CN108470534B (en) * | 2018-05-25 | 2023-08-04 | 南京微芯华谱信息科技有限公司 | Pixel unit circuit applied to self-luminescence, test circuit and test method |
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