Dual-Gate Pixel Driving Circuit for OLED Threshold Voltage Control
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Solution Overview
Problem
Conventional OLED display devices face issues of high threshold voltage and low mobility in driving transistors due to applied voltage, leading to increased compensation requirements and costs.
Innovation Solution
A pixel driving circuit with a dual-gate structure and two data writing modules that share the voltage load across the gates, reducing the threshold voltage and mobility shifts, and thus the demand for driving voltage output capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a higher voltage is applied on the control end of the driving transistor to control the current flowing through it, then the current control capability is improved, but the threshold voltage becomes greater and the mobility becomes lower
Solution Approach 1:
The driving transistor is divided into a dual-gate structure with first and second gates that can be independently controlled. This segmentation allows the voltage control function to be distributed across two gates, enabling better management of the voltage-stress relationship and maintaining transistor performance while achieving current control.
Solution Approach 2:
The invention changes the control parameter from a single voltage value to a combination of two voltage values (first gate voltage and second gate voltage). By adjusting these two parameters independently, the system can achieve the required current control while maintaining optimal threshold voltage and mobility through coordinated voltage management.
2Reliability
If the threshold voltage becomes greater and the mobility becomes smaller, then the compensation capability of the compensation circuit needs to be higher, but this increases the cost of the OLED display
Solution Approach 1:
The dual-gate structure segments the voltage control function, allowing the system to maintain stable transistor characteristics with lower threshold voltage and mobility shifts. This reduces the compensation burden on additional circuits, thereby lowering overall system complexity and cost.
Solution Approach 2:
The driving transistor's own dual-gate structure provides the compensation function by independently adjusting gate voltages to counteract threshold voltage shifts and mobility changes. This self-compensation mechanism eliminates or reduces the need for external compensation circuits, reducing device complexity and cost.
Data Source
AI summary
The present disclosure proposes a pixel driving circuit and a display device. The pixel driving circuit comprises a driving transistor, a first data writing module and a second data writing module. The driving transistor comprises: a channel in a channel layer, a first gate in a first gate layer, and a second gate in a second gate layer, and an output end electrically connected to a light generating unit. The first gate and the second gate are respectively located at opposite sides of the channel. The first data writing module comprises an output end electrically connected to the first gate. The second data writing module comprises an output end electrically connected to the second gate.