Emission Control Driver for OLED Brightness Uniformity
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Solution Overview
Problem
Non-uniformity in threshold voltages of transistors in organic light emitting displays leads to non-uniform brightness, affecting picture quality due to variations during manufacturing.
Innovation Solution
An emission control driver with emission control signal generating circuits that use scan signals to compensate for threshold voltages, including switching devices and capacitors to maintain uniform voltage between the gate and source of transistors, reducing power consumption and improving brightness uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional pixel circuits are used without threshold voltage compensation, then device complexity is reduced, but brightness uniformity deteriorates due to non-uniform transistor threshold voltages
Solution Approach 1:
The pixel circuit is divided into multiple functional blocks: a threshold voltage compensation circuit that generates compensation signals based on transistor threshold voltages, and a main drive circuit that uses these compensation signals to control the OLED. This segmentation allows threshold voltage compensation without requiring complete redesign of the entire pixel circuit.
Solution Approach 2:
The compensation circuit generates threshold voltage compensation signals in advance during the initialization phase, before the main display operation begins. This preliminary action ensures that the compensation is already in place when data signals are applied, eliminating brightness non-uniformity from the start rather than requiring corrective measures during operation.
2Use of energy by moving object
If emission control signals are generated using conventional methods, then power consumption is higher, but signal generation reliability is maintained
Solution Approach 1:
The emission control signal generation circuit is merged with the threshold voltage compensation circuit, allowing both functions to share common components such as switching devices and capacitors. This integration reduces the total number of components and power consumption while maintaining the reliability of emission control signal generation through the established compensation mechanism.
Solution Approach 2:
The emission control signals are generated periodically in synchronization with the scan signals and frame timing, rather than continuously. This periodic generation reduces power consumption by activating components only when needed, while maintaining reliable control of the OLED emission timing through precise synchronization with the display refresh cycle.
Data Source
AI summary
An emission control driver compensates for the threshold voltages of transistors to provide uniform brightness using a plurality of emission control signal generating circuits.