AMOLED real-time compensation system

Patent metadata

Field	Value
Publication number	US-9940878-B2
Application number	US-201514787770-A
Country	US
Kind code	B2
Filing date	Oct 12, 2015
Priority date	Sep 9, 2015
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

The present invention provides an AMOLED real-time compensation system, comprising a source drive and real-time detection compensation integration module ( 2 ), in which a first operational amplifier and a second operational amplifier are provided. The positive, negative input ends of the first operational amplifier (Y 1 ) respectively receive the drive thin film transistor source target voltage and the drive thin film transistor source actual voltage, and the output end outputs the difference value (ΔV) of the drive thin film transistor source target voltage and the actual voltage to implement real-time detection to a threshold voltage deviation of the drive thin film transistor (T 2 ). Then, the second operational amplifier (Y 2 ) accumulates the voltage difference value (ΔV) of the drive thin film transistor source target voltage and the actual voltage outputted by the outputted end of the first operational amplifier (Y 1 ) to the data signal (data) voltage to implement real-time compensation to the threshold voltage deviation of the drive thin film transistor (T 2 ). The real-time measurement, real-time compensation to each pixel unit can be realized and all the gray scale data signals (data) can be effectively compensated.

First claim

What is claimed is:

1. An Active Matrix Organic Light Emitting Display (AMOLED) real time compensation method, applied to an AMOLED real-time compensation system, comprising a plurality of pixel units aligned in array, which each includes a switch thin film transistor, a drive thin film transistor, a detection thin film transistor and an organic light emitting diode, a source drive and real-time detection compensation integration circuit, which includes a latch and buffer circuit, a first operational amplifier and a second operational amplifier,
wherein the latch and buffer circuit, having a latch and a buffer, receives, latches, buffers and outputs a data signal; the first operational amplifier is electrically coupled to the pixel unit, and positive, negative input ends of the first operational amplifier respectively receive a drive thin film transistor source target voltage and a drive thin film transistor source actual voltage, and an output end of the first operational amplifier outputs a difference value of the drive thin film transistor source target voltage and the actual voltage to implement real-time detection to a threshold voltage deviation of the drive thin film transistor; the second operational amplifier is electrically coupled to the latch and buffer circuit and the pixel unit, and a positive input end of the second operational amplifier receives the data signal, and a negative input end of the second operational amplifier is grounded through a first switch and then coupled to the output end of the first operational amplifier, and an output end first of the second operational amplifier outputs a data signal voltage and then outputs a sum of the data signal voltage and an output end voltage of the first operational amplifier to implement real-time compensation to the threshold voltage deviation of the drive thin film transistor,
wherein a gate of the switch thin film transistor receives a gate drive signal, and a source is electrically coupled to the output end of the second operational amplifier through the data line; a gate of the drive thin film transistor is electrically coupled to a drain of the switch thin film transistor, and a drain is coupled to a constant high voltage level, and a source is coupled to a node; a gate of the detection thin film transistor receives a detection start signal, and a source is coupled to the node, and a drain is electrically coupled to the negative input end of the first operational amplifier through the detection line; an anode of the organic light emitting diode is electrically coupled to the node, and a cathode is grounded, wherein the method comprises five stages of:
a data signal input stage: the data signal is inputted into the source drive and real-time detection compensation integration circuit to be latched in the latch and buffer circuit;
a data signal output stage: as the gate drive signal is high voltage level, and the data signal is high voltage level, and the detection start signal is low voltage level, and the first switch is grounded, and then the output end of the second operational amplifier outputs the data signal, and the switch thin film transistor is activated by the gate drive signal provided to the gate of the switch thin film transistor, and the drive thin film transistor is activated by the data signal from the drain of the switch thin film transistor; a drive thin film transistor source target voltage is calculated and acquired;
a drive thin film transistor threshold voltage deviation real-time detection stage: the detection start signal is high voltage level, and the detection thin film transistor is activated by detection start signal provided to the gate of detection thin film transistor, and the positive, negative input ends of the first operational amplifier respectively receive the drive thin film transistor source target voltage and the drive thin film transistor source actual voltage, and the output end of the first operational amplifier outputs the difference value of the drive thin film transistor source target voltage and the actual voltage;
a drive thin film transistor threshold voltage deviation real-time compensation stage: the first switch is coupled to the output end of the first operational amplifier, and the positive input end of the second operational amplifier receives the data signal, and the negative input end is coupled to the output end of the first operational amplifier, and the output end outputs the sum of the data signal voltage and the output end voltage of the first operational amplifier;
a display stage: the gate drive signal and the detection start signal are changed to be low voltage level, and the switch thin film transistor and the detection thin film transistor are respectively deactivated by the gate drive signal provided to the gate of the switch thin film transistor and by the detection start signal provided to the gate of detection thin film transistor, and the organic light emitting diode emits light for display.

2. The AMOLED real-time compensation method according to claim 1 , wherein the pixel unit further comprises a storage capacitor, and one end of the storage capacitor is electrically coupled to the gate of the drive thin film transistor, and the other end of the storage capacitor is electrically coupled to the node.

3. The AMOLED real-time compensation method according to claim 1 , wherein the source drive and real-time detection compensation integration circuit further comprises a current detector connected with a detection line through a second switch.

4. The AMOLED real-time compensation method according to claim 3 , further comprising a storage device employed to store the threshold voltage deviation of the organic light emitting diode.

5. The AMOLED real-time compensation method according to claim 4 , further comprising an organic light emitting diode threshold voltage deviation detection stage before the data signal input stage: the gate drive signal is high voltage level, and the data signal is low voltage level, and the detection start signal is high voltage level, and the first switch is grounded, and the second switch is closed, and the drive thin film transistor is disconnected, and the detection thin film transistor is connected, and the current detector is connected with the detection line through the second switch, and the current detector discharges the organic light emitting diode through the detection line, and the current detector transmits a measured current value for calculating an organic light emitting diode threshold voltage deviation to be stored in the storage device;
in the next data signal input stage: the data signal with the organic light emitting diode threshold voltage deviation is compensated, and then the compensated data signal is inputted into the source drive and real-time detection compensation integration circuit.

6. The AMOLED real-time compensation method according to claim 1 , wherein the first switch is grounded under control of low voltage level, and coupled to the output end of the first operational amplifier under control of high voltage level.

Assignees

• Shenzhen China Star Optoelect

Inventors

• Liang Pengfei

Classifications

• G09G2320/043

  Preventing or counteracting the effects of ageing · CPC title

• G09G2310/027

  Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters · CPC title

• G09G2310/0291

  Details of output amplifiers or buffers arranged for use in a driving circuit · CPC title

• G09G2300/0838

  with level shifting · CPC title

• G09G2320/0295

  by monitoring each display pixel · CPC title