A voltage-programmable amoled pixel circuit and its driving method

A technology of a pixel circuit and a driving method, applied in the field of flat display, can solve the problems of accelerating the threshold voltage and mobility of TFTs, reducing the compensation effect, process deviation, etc., and achieving the threshold voltage degradation phenomenon is slowed down, and the degradation of mobility is alleviated and reduced. effect of influence

Active Publication Date: 2018-07-06
SHANGHAI ADVANCED RES INST CHINESE ACADEMY OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] However, the traditional threshold voltage compensation method usually compensates the driving transistor in the pixel. The voltage programming AMOLED pixel circuit proposed above also compensates the driving transistor T2'. Although this kind of compensation method can compensate the threshold voltage to a certain extent The voltage drift is compensated, but the simulation and test results show that as the threshold voltage drift increases, the current flowing through the OLED also changes to a certain extent.
Studies have shown that in addition to process deviations, long-term biasing will also cause threshold voltage and mobility drift of TFTs, while the driving transistor compensated by traditional compensation methods is in a biasing state throughout the light-emitting phase, which will accelerate the threshold of TFTs. Voltage and mobility changes, and when the threshold voltage changes to a certain extent, the compensation effect of traditional compensation methods will be greatly reduced

Method used

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  • A voltage-programmable amoled pixel circuit and its driving method
  • A voltage-programmable amoled pixel circuit and its driving method
  • A voltage-programmable amoled pixel circuit and its driving method

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Embodiment 1

[0053] Such as image 3 As shown, this embodiment provides a voltage-programmable AMOLED pixel drive circuit, the drive circuit includes: a first switch transistor T1, a second switch transistor T2, a third switch transistor T3, a fourth switch transistor T4, a fifth switch transistor T5, sixth switching transistor T6, seventh switching transistor T7, driving transistor T drive , the first capacitor C1, the second capacitor C2 and the organic light-emitting diode OLED, referred to as 8T2C circuit. The first capacitor C1 and the second capacitor C2 are storage capacitors.

[0054] The first electrode of the first switching transistor T1 is connected to the power supply voltage, the second electrode is connected to the second electrode of the second switching transistor T2, the first electrode of the sixth switching transistor T6, and the seventh switching transistor T7 The first electrode of the first electrode and the first terminal and gate of the first capacitor C1 are con...

Embodiment 2

[0063] Such as Figure 3 ~ Figure 8 As shown, according to Embodiment 1, the driving method of the voltage-programmable AMOLED pixel circuit provided in this embodiment includes a pre-charging stage, a threshold voltage detection stage, a programming stage, and a light-emitting stage. The specific introduction is as follows:

[0064] Precharge phase: as Figure 4 As shown, the first control signal Vscan1 and the second control signal Vscan2 input low level, the third control signal Vscan3 and the fourth control signal Vscan4 input high level, so that the first switching transistor T1, the second switching transistor T2, the third switching transistor T1 The switch transistor T3, the fourth switch transistor T4, and the seventh switch transistor T7 are turned on, and the fifth switch transistor T5 is turned off. Since the fourth control signal Vscan4 is at a high level, the organic light emitting diode OLED is in a reverse-biased state that does not emit light. This reverse bi...

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PUM

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Abstract

The present invention provides a voltage programming type AMOLED pixel circuit, comprising: a first switching transistor, a second switching transistor, a third switching transistor, a fourth switching transistor, a fifth switching transistor, a sixth switching transistor, a seventh switching transistor, a driving A transistor, a first capacitor, a second capacitor and an organic light emitting diode. The present invention provides a voltage-programmed AMOLED pixel circuit and its driving method, which are used to solve the problem that the driving transistor compensated by the traditional compensation method in the prior art is in a biased state during the entire light-emitting stage, which will accelerate the threshold voltage and mobility of TFTs. Changes, and when the threshold voltage changes to a certain extent, the compensation effect of the traditional compensation method is greatly reduced.

Description

technical field [0001] The invention relates to the field of plane display technology, in particular to a voltage-programmed AMOLED pixel circuit and a driving method thereof. Background technique [0002] AMOLED (Active-matrix organic light-emitting diode, active matrix organic light-emitting diode), as a new display technology, has received more and more attention in recent years, and the current mainstream AMLCD (Active matrix liquid crystal display , active matrix liquid crystal display) display technology, it has many advantages, such as low cost, low power consumption, wide viewing angle, high speed, colorful and so on. However, the display effect of AMOLED is greatly affected by the instability of the process, which greatly limits its area array size, lifespan, display uniformity and other performances. In AMLCD pixels, thin film transistors (Thin Film Transistors, TFTs) are usually used as switches, and changes in the electrical characteristics of TFTs can be compen...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G09G3/3233
CPCG09G2300/0819
Inventor 汪辉黄尊恺田犁章琦汪宁黄景林叶汇贤
Owner SHANGHAI ADVANCED RES INST CHINESE ACADEMY OF SCI
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