Pixel Circuit Compensation for Threshold Voltage Drift
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Solution Overview
Problem
Threshold voltage drift in pixel circuits of oxide processes affects display performance, posing challenges to the design of pixel circuits.
Innovation Solution
A pixel circuit with a driving circuit, writing circuit, light-emitting control circuit, and compensation circuits to manage threshold voltage drift, including a first and second compensation circuit to reset and decouple terminals as needed, stabilizing the driving current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If internal compensation circuits are added to pixel circuits to compensate for threshold voltage drift, then display performance is improved, but device complexity increases
Solution Approach 1:
The pixel circuit is divided into multiple functional modules: a driving circuit for generating driving current, a writing circuit for signal input, a light-emitting control circuit for controlling current flow, and compensation circuits for threshold voltage correction. Each module performs a specific function, allowing the complex compensation task to be distributed across separate components rather than requiring a monolithic complex circuit design.
Solution Approach 2:
The compensation circuits perform preliminary action by resetting the control terminal voltage to an initial value before the driving circuit operates. This preliminary voltage reset compensates for threshold voltage drift in advance, ensuring the driving circuit starts with accurate voltage levels. The writing circuit also performs preliminary action by providing control signals to configure the compensation circuits before actual driving occurs.
2Reliability
If compensation circuits are used to reset control terminal voltage, then threshold voltage drift is compensated, but device complexity increases
Solution Approach 1:
The compensation circuits are integrated with the existing pixel circuit structure rather than being completely separate additions. The compensation circuits share terminals and control signals with the driving circuit, merging multiple functions into a unified structure. This reduces overall complexity compared to having entirely separate compensation systems.
Solution Approach 2:
The writing circuit serves multiple functions: it provides control signals to configure the compensation circuits, inputs data signals to the driving circuit, and manages the overall pixel operation. This multi-functionality reduces the need for dedicated separate circuits for each function, thereby reducing device complexity while maintaining compensation capabilities.
Data Source
AI summary
A pixel circuit, a pixel unit and a method for driving a pixel circuit. The pixel circuit includes: a driving circuit, writing circuit, light-emitting control circuit, first and second compensation circuits. The first compensation circuit is configured to electrically couple or decouple a control terminal of the driving circuit to/from a first terminal of the driving circuit according to a signal of a second control signal terminal of the pixel circuit. The second compensation circuit is configured to provide a voltage of a first voltage terminal of the pixel circuit to an output signal terminal of the pixel circuit under control of a third control signal terminal of the pixel circuit, and to electrically couple or decouple the output signal terminal to/from the control terminal of the driving circuit, according to a signal of a fourth control signal terminal of the pixel circuit.