OLED Pixel Circuit Compensation for Display Uniformity
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Solution Overview
Problem
Organic electroluminescent displays suffer from poor display effects due to variations in threshold voltages among transistors, leading to non-uniform display performance.
Innovation Solution
A pixel circuit design incorporating a driving sub-circuit, compensation sub-circuit, and a charging mechanism that connects the third node to a power supply terminal to compensate for threshold voltage variations, using transistors and capacitors to stabilize the first node potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pixel circuits are used without compensation mechanisms, then the circuit structure is simple, but threshold voltage variations cause non-uniform display performance
Solution Approach 1:
The compensation sub-circuit performs preliminary compensation of threshold voltage variations before the data writing stage. By connecting the first node to the power supply terminal through the compensation sub-circuit during the compensation stage, the gate-source voltage is pre-adjusted to compensate for threshold voltage differences, ensuring uniform display performance without requiring complex real-time adjustment mechanisms
Solution Approach 2:
The compensation sub-circuit acts as an intermediary between the power supply terminal and the first node. It introduces an intermediate compensation node that mediates the voltage adjustment process, allowing threshold voltage variations to be compensated through controlled voltage transfer from the power supply terminal during the compensation stage
2Reliability
If the gate-source voltage is stabilized independently of power supply variations, then display uniformity improves, but additional compensation circuits are required
Solution Approach 1:
The compensation sub-circuit performs preliminary compensation of threshold voltage variations before the data writing stage. By connecting the first node to the power supply terminal through the compensation sub-circuit during the compensation stage, the gate-source voltage is pre-adjusted to compensate for threshold voltage differences, ensuring uniform display performance without requiring complex real-time adjustment mechanisms
Solution Approach 2:
The compensation sub-circuit utilizes the power supply terminal itself as the compensation source, allowing the circuit to self-compensate for threshold voltage variations using existing power supply voltage rather than requiring external compensation signals or complex reference voltage generation circuits
Data Source
AI summary
A display apparatus, a pixel circuit, and a method for driving a pixel circuit are provided. The pixel circuit comprises: a first storage sub-circuit, connected between a first node and a second node; a driving sub-circuit, used to control connection or disconnection between the third node and the fourth node under control of the first node; wherein the third node is connected to a first power supply terminal; a light-emitting control sub-circuit, used to control connection or disconnection between the fourth node and the first electrode of the sub-pixel; a second storage sub-circuit, used to store a potential of the first node; a data writing sub-circuit, used to input a voltage to the second node; and a compensation sub-circuit, used to control connection or disconnection between the first node and the third node under control of the first scanning signal terminal, or, used to control connection or disconnection between the first node and the fourth node under the control of the first scanning signal terminal. The present disclosure can improve the display effect.