Pixel Circuit Gate Voltage Settling Time Reduction
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Solution Overview
Problem
Current-type pixel circuits face a long settling time for gate voltage, which hinders the driving transistor's ability to quickly follow data current signals during microsecond scanning, affecting the establishment of operating current for light-emitting devices.
Innovation Solution
A pixel circuit with an operating current generating module and a light emission control module, along with a driving control circuit that includes a data current module and a current adjusting module, allows for quick establishment of gate voltage through interaction between data and compensation currents, utilizing transistors and capacitors to manage and control current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current-type pixel circuits are used to compensate threshold voltage drift and channel mobility, then the stability of driving transistor is improved, but the settling time of gate voltage becomes too long
Solution Approach 1:
The pixel circuit is divided into two independent modules: a voltage-type pixel circuit for fast response and a current-type pixel circuit for stability compensation. The voltage-type module quickly establishes gate voltage to follow data current signals, while the current-type module compensates for threshold voltage drift and channel mobility variations, resolving the contradiction between speed and stability.
Solution Approach 2:
The patent combines voltage-type and current-type pixel circuit modules into a unified structure where both work simultaneously. The voltage-type module provides fast settling time, while the current-type module provides stability compensation, achieving both quick response and long-term stability without the drawbacks of using either type alone.
2Speed
If gate voltage settling time is reduced for microsecond scanning, then the responsiveness to data current signal is improved, but the compensation effect for threshold voltage drift is weakened
Solution Approach 1:
The pixel circuit is divided into two independent modules: a voltage-type pixel circuit for fast response and a current-type pixel circuit for stability compensation. The voltage-type module quickly establishes gate voltage to follow data current signals, while the current-type module compensates for threshold voltage drift and channel mobility variations, resolving the contradiction between speed and stability.
Solution Approach 2:
The current-type pixel circuit module continuously compensates for threshold voltage drift and channel mobility variations throughout the display operation, ensuring that the compensation effect is maintained over time while the voltage-type module provides continuous fast response to data signals.
3Loss of time
If voltage-type pixel circuits are used for fast response, then the settling time is reduced, but the ability to compensate threshold voltage drift is lost
Solution Approach 1:
The patent combines voltage-type and current-type pixel circuit modules into a unified structure where both work simultaneously. The voltage-type module provides fast settling time, while the current-type module provides stability compensation, achieving both quick response and long-term stability without the drawbacks of using either type alone.
Data Source
AI summary
A pixel circuit and a display device are provided. The pixel circuit includes a pixel unit which includes an operating current generating module and a light emission control module. The operating current generating module has a gate voltage terminal and is configured to generate an operating current according to a voltage of the gate voltage terminal. The light emission control module is connected in series with the operating current generating module and configured to control whether to provide the operating current to a light emitting device according to a light emission control signal. The driving control circuit includes: a data current module, configured to provide a data current and to input the data current to the gate voltage terminal; and a current adjusting module, configured to control whether to input a compensation current to the gate voltage terminal according to a current value of the operating current.