OLED Pixel Circuit Voltage Stabilization for Luminance Uniformity
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Solution Overview
Problem
The voltage instability at certain nodes in OLED pixel circuits affects the uniformity of display luminance in OLED display devices during adjustments in pulse width of the light emitting control signal.
Innovation Solution
A pixel circuit with a voltage stabilizing sub-circuit that maintains a stable voltage level at the second node by connecting one terminal to a voltage stabilizing signal terminal, preventing the influence of voltage level changes from the light emitting control signal, comprising an input sub-circuit, driving sub-circuit, light emitting control sub-circuit, and voltage stabilizing sub-circuit, with specific transistor configurations and capacitors to manage signal voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the pulse width of the light emitting control signal is adjusted to control display luminance, then the luminance adjustment capability is improved, but the voltage stability at certain nodes deteriorates
Solution Approach 1:
A voltage stabilizing sub-circuit is introduced as an intermediary component between the light emitting control sub-circuit and the second node. This stabilizing sub-circuit includes a stabilizing transistor and stabilizing capacitor that work together to filter and stabilize the voltage at the second node, preventing voltage fluctuations caused by light emitting control signal adjustments while maintaining the luminance adjustment capability.
Solution Approach 2:
The voltage stabilizing sub-circuit is designed to proactively compensate for potential voltage fluctuations before they affect the pixel circuit operation. The stabilizing capacitor stores energy and the stabilizing transistor activates when voltage deviations are detected, providing beforehand cushioning against voltage instability during luminance adjustment processes.
2Manufacturing precision
If the voltage stabilizing sub-circuit is added to stabilize voltage levels, then the luminance uniformity is improved, but the device complexity increases
Solution Approach 1:
The voltage stabilizing sub-circuit is merged with the existing pixel circuit structure by integrating the stabilizing transistor and capacitor into the available circuit nodes and signal paths. The stabilizing transistor shares control signals with other circuit components, and the stabilizing capacitor is placed at the second node which is already part of the light emitting control path, thereby minimizing additional complexity while achieving voltage stabilization.
Data Source
AI summary
A pixel circuit and a driving method thereof, and a display device. The pixel circuit includes an input sub-circuit, a driving sub-circuit, a light emitting control sub-circuit, a light emitting sub-circuit and a voltage stabilizing sub-circuit; the voltage stabilizing sub-circuit is connected respectively to a second node and a voltage stabilizing signal terminal in the pixel circuit, and configured to stabilize a voltage level at the second node under control of a voltage stabilizing signal from the voltage stabilizing signal terminal, and the voltage level of the voltage stabilizing signal is unchanged during driving process of the pixel circuit.