Pixel Circuit Voltage Stability via Dynamic Switch Control
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Solution Overview
Problem
In Active-Matrix Organic Light-Emitting Diode (AMOLED) pixel circuits, the non-uniform drain-to-source voltage affects the gate-to-source voltage of the driving transistor, leading to display non-uniformity due to the inability to accurately apply a voltage signal stored in the storage capacitor between the gate and source electrodes.
Innovation Solution
A pixel circuit comprising a driving circuit, an energy storage circuit, and a switch control circuit, where the energy storage circuit is configured to store voltage and the switch control circuit controls the energy storage circuit to be electrically coupled to the driving circuit under a light-emission control signal, ensuring a stable voltage application between the gate and source electrodes of the driving transistor, thereby preventing the adverse effect of drain-to-source voltage on the gate-to-source voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the energy storage circuit is continuously coupled to the driving circuit, then the voltage signal can be maintained, but the drain-to-source voltage affects the gate-to-source voltage causing display non-uniformity
Solution Approach 1:
The patent applies the dynamics principle by making the coupling state of the energy storage circuit changeable rather than fixed. The switch control circuit dynamically adjusts the connection between the energy storage circuit and driving circuit based on different working stages (initialization, data write-in, light-emission), allowing the system to optimize performance for each stage while avoiding the non-uniformity problem during light-emission.
Solution Approach 2:
The patent segments the operation into distinct stages with different circuit configurations. During initialization and data write-in stages, the energy storage circuit is coupled to the driving circuit; during the light-emission stage, the coupling is controlled to prevent drain-to-source voltage interference. This temporal segmentation resolves the contradiction between maintaining voltage stability and ensuring display uniformity.
2Ease of operation
If the light-emission control transistor is used to control light emission, then light emission can be controlled, but the non-uniform drain-to-source voltage of the light-emission control transistor causes non-uniform gate-to-source voltage of the driving transistor
Solution Approach 1:
The patent extracts the problematic light-emission control function from the driving transistor's gate control path. By using a separate light-emission control transistor that operates independently from the energy storage circuit coupling, the design removes the source of non-uniform drain-to-source voltage from the gate-to-source voltage determination, thereby solving the uniformity problem while maintaining light emission control capability.
Solution Approach 2:
The patent introduces a switch control circuit as an intermediary between the energy storage circuit and the driving circuit. This intermediary component decouples the direct relationship between the light-emission control transistor and the driving transistor's gate voltage, allowing the light-emission control to function without directly affecting the gate-to-source voltage uniformity through its drain-to-source voltage variations.
3Manufacturing precision
If the energy storage circuit is decoupled from the driving circuit during light-emission stage, then display uniformity is improved, but additional voltage control complexity is introduced
Solution Approach 1:
The switch control circuit performs multiple functions: it controls the coupling between the energy storage circuit and driving circuit, manages the light-emission control signal transmission, and coordinates with the light-emission control transistor. By making this single circuit component multi-functional, the patent achieves display uniformity improvement without proportionally increasing overall system complexity.
Data Source
AI summary
The present disclosure provides a pixel circuit, a pixel driving method and a display device. The pixel circuit includes a driving circuit, an energy storage circuit and a switch control circuit. A first end of the energy storage circuit is coupled to a control end of the driving circuit, a second end of the energy storage circuit is coupled to a first end of the driving circuit via the switch control circuit, and the energy storage circuit is configured to store a voltage. The switch control circuit is configured to control the second end of the energy storage circuit to be electrically coupled to a voltage application end or the first end of the driving circuit under the control of a light-emission control signal from a light-emission control line. The driving circuit is configured to generate a driving current in accordance with a voltage between the control end and first end of the driving circuit.