Shared Pixel Driving Circuit for Flicker-Free Low-Speed Display
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Solution Overview
Problem
Electroluminescent display devices face issues such as flickering during low-speed driving, inaccurate grayscale representation, and voltage drops due to increased resistance in high-potential voltage lines, which degrade image quality and power consumption.
Innovation Solution
A display panel design with a common circuit shared by neighboring pixels, including a high-potential voltage providing circuit and a reference voltage providing circuit, along with two data lines per pixel row connected to different data lines, and a pixel driving circuit that compensates for voltage drops in power lines, enhancing image quality and reducing bezel area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If electroluminescent display devices are driven at low speeds to reduce power consumption, then power consumption is reduced, but image quality degrades due to flickering and inability to maintain luminance
Solution Approach 1:
The patent applies preliminary action by pre-charging the gate node of the driving transistor to a reference voltage level before the low-speed driving period begins. This preliminary charging ensures that when low-speed driving occurs, the gate node already has sufficient voltage to maintain proper transistor operation and prevent flickering, thus allowing power reduction without image quality degradation.
Solution Approach 2:
The patent implements beforehand cushioning by introducing a compensation circuit that anticipates voltage drops and leakage current effects during low-speed driving. The circuit pre-compensates for these effects by maintaining the gate node voltage within an appropriate range, cushioning against the harmful effects of leakage current and ensuring stable luminance output even during extended low-speed operation periods.
2Measurement precision
If the vertical resolution of the display panel is increased, then image quality is improved, but the sampling time for threshold voltage compensation becomes insufficient
Solution Approach 1:
The patent applies preliminary action by performing threshold voltage compensation during the previous frame's time period rather than during the current frame's sampling period. This allows the compensation process to occur in advance, freeing up the current sampling period for other operations and enabling high vertical resolution without sacrificing sampling time.
Solution Approach 2:
The patent resolves the time conflict by moving the compensation operation to a different temporal dimension - specifically, utilizing the time resources of the previous frame period. This dimensional shift in when compensation occurs allows simultaneous achievement of high resolution and adequate sampling time in the current frame.
3Area of stationary object
If the width of the high-potential voltage line is reduced due to larger display size and higher resolution, then device size is reduced, but voltage drop increases significantly
Solution Approach 1:
The patent implements feedback by incorporating a voltage compensation circuit that monitors and responds to voltage drops in the high-potential voltage line. The circuit detects voltage variations and automatically adjusts compensation signals to maintain stable operation of the pixel driving circuits, enabling use of thinner voltage lines without suffering from excessive voltage drop.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting voltage levels and timing parameters in the pixel driving circuit based on detected voltage drop conditions. By changing operational parameters such as gate voltage levels and timing sequences, the circuit compensates for reduced voltage line width effects, allowing smaller device size without significant voltage loss.
Data Source
AI summary
The disclosure provides a display panel configured to enhance image quality and an electroluminescent display device including the same, and a pixel driving circuit. An electroluminescent display device according to an embodiment of the disclosure comprises a plurality of pixels including at least two pixels and a common circuit disposed between the plurality of pixels. One of the plurality of pixels includes a driving transistor including a first node, a second node, and a third node, a capacitor connected to a fourth node electrically shared by the plurality of pixels and the second node, a second transistor connected with the first node and a data line, and a light emitting element electrically connected with the driving transistor. The common circuit includes a high-potential voltage providing circuit providing a high-potential voltage to the fourth node and a reference voltage providing circuit providing a reference voltage.