Dual-Gate Driving Circuit for OLED Brightness Uniformity
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Solution Overview
Problem
Organic light-emitting diode (OLED) displays face issues with uneven brightness due to differences in threshold voltages of driving transistors, which affect pixel brightness and overall display uniformity.
Innovation Solution
A driving circuit comprising a driving transistor, a writing module, a compensation module, and a light-emitting control module, which compensates the threshold voltage of the driving transistor through specific signal control, ensuring uniform brightness across the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional driving circuit without compensation is used, then the device complexity is low, but the brightness uniformity deteriorates due to threshold voltage differences
Solution Approach 1:
The gate electrode is divided into two independent gates (first gate and second gate), allowing separate control of the driving transistor. This segmentation enables independent threshold voltage compensation through the compensation module while maintaining the driving function through the writing module, thus improving brightness uniformity without excessive complexity increase.
Solution Approach 2:
The compensation module uses the same scan signal line and control signal line as the writing module, making these signal lines serve dual purposes. The first control signal line carries both writing control signals and compensation control signals at different times, reducing the need for additional dedicated compensation signal lines and thereby limiting the increase in device complexity.
2Manufacturing precision
If additional scan signal lines are added for compensation, then the brightness uniformity improves, but the device complexity and resolution deteriorate
Solution Approach 1:
The compensation module shares the scan signal line and control signal line with the writing module. The same physical signal lines are used to transmit both writing signals and compensation signals by controlling the timing and state of transistors, thereby achieving threshold voltage compensation without increasing the number of signal lines, maintaining display resolution, and avoiding additional routing complexity.
3Adaptability or versatility
If a dual-gate driving transistor is used, then the threshold voltage compensation capability improves, but the manufacturing precision of the transistor itself deteriorates
Solution Approach 1:
The gate electrode is segmented into two independent gates that can be controlled separately. This allows the first gate to be used for normal driving operations while the second gate is specifically used for threshold voltage compensation, enabling the transistor to adapt to threshold voltage variations without requiring higher manufacturing precision for the entire transistor structure.
Solution Approach 2:
The invention changes the electrical parameters (voltage) applied to the two gates independently. By adjusting the voltage on the second gate through the compensation module, the threshold voltage of the driving transistor can be dynamically adjusted to compensate for manufacturing variations, thereby improving adaptability without demanding stricter manufacturing precision.
Data Source
AI summary
Embodiments of the present disclosure are directed to a driving circuit, a driving method, and a display panel. The driving circuit includes a driving transistor, a writing module, a compensation module, a light-emitting control module and a light-emitting device. The driving transistor has a first gate connected to a first node, a second gate connected to a second node, a source connected to a first power supply terminal, and a drain connected to the third node. The writing module is connected to the first node and the third node. The compensation module is connected to the first node, the second node and the third node. The light-emitting control module is connected to the third node and the fourth node. An anode of the light-emitting device is connected to the fourth node, and a cathode of the light-emitting device is connected to the second power supply terminal.