OLED Pixel Driving Circuit Reset Mechanism for Narrow Bezel Displays
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Solution Overview
Problem
Existing pixel driving circuits for OLED displays have a complicated structure due to the need for a sensing signal line to introduce a reset signal, leading to increased area requirements and hindering the development of narrow-bezel OLED products with high pixels per inch (PPI) displays.
Innovation Solution
A pixel driving circuit with a data input switch circuit, driving switch circuit, reset switch circuit, light-emitting device, storage capacitor, and intrinsic capacitor, where the intrinsic capacitor's capacitance value is greater than or equal to a preset multiple of the storage capacitor's, and the threshold voltage detection stage duration is longer than a preset duration, allowing the reset switch circuit to reset the driving switch circuit without a reset signal, thus eliminating the need for a sensing signal line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sensing signal line is added to introduce a reset signal to the pixel driving circuit, then the reset function can be achieved, but the circuit structure becomes complicated and the area increases
Solution Approach 1:
The patent extracts and eliminates the sensing signal line from the pixel driving circuit by redesigning the reset mechanism. The reset switch circuit is directly coupled to the data input switch circuit, allowing the reset signal to be transmitted through existing signal lines rather than requiring a dedicated sensing signal line, thus simplifying the circuit structure while maintaining the reset function
Solution Approach 2:
The patent makes existing signal lines serve multiple functions. The data signal line is used both for transmitting data signals and for transmitting reset signals during the reset phase. This multi-functionality eliminates the need for separate sensing signal lines, reducing circuit complexity and area
2Reliability
If a sensing signal line is added to introduce a reset signal, then the reset function can be achieved, but the area requirement increases hindering narrow-bezel OLED product development
Solution Approach 1:
The patent removes the sensing signal line from the circuit design, thereby eliminating the area it would occupy. The reset function is achieved through direct coupling between the reset switch circuit and data input switch circuit, using existing signal pathways that already occupy space in the circuit layout
Solution Approach 2:
The patent merges the reset signal transmission function with the existing data signal line. By combining multiple functions into existing circuit elements, the total circuit area is reduced, enabling narrower bezels in OLED displays
3Measurement precision
If the intrinsic capacitor capacitance value is increased to be greater than or equal to a preset multiple of the storage capacitor, then the compensation precision for threshold voltage and mobility drifts is improved, but the device area increases
Solution Approach 1:
The patent changes the capacitance value parameter of the intrinsic capacitor to be greater than or equal to a preset multiple (e.g., 8 times) of the storage capacitor capacitance value. This parameter adjustment improves the precision of threshold voltage and mobility drift compensation by ensuring adequate charge storage and comparison accuracy during the detection phase
Data Source
AI summary
A pixel driving circuit, array substrate, display device and method for driving the pixel driving circuit are provided, the circuit includes: a control terminal and a first terminal of a driving switch circuit are respectively coupled to a first terminal of a data input switch circuit and an anode of a light-emitting device, and two terminals of a storage capacitor are respectively coupled to the control terminal of the driving switch circuit and the anode of the light-emitting device, two terminals of an intrinsic capacitor are respectively coupled to a cathode and the anode of the light-emitting device, a first terminal and a second terminal of a reset switch circuit are respectively coupled to the anode and the cathode of the light-emitting device, a capacitance of the intrinsic capacitor is greater than or equal to a preset multiple of a capacitance of the storage capacitor.