Shared Pixel Driving Circuit for Flicker-Free OLED Grayscale
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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 in high-potential voltage lines due to increased resolution and size, leading to image quality degradation.
Innovation Solution
A display panel design that includes a common circuit shared by neighboring pixels, with a high-potential voltage providing circuit and a reference voltage providing circuit, and a pixel driving circuit with two data lines per pixel row to prevent flickering and voltage drops, allowing for accurate grayscale representation and high-speed driving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If pixels are driven at a reduced frame rate to reduce power consumption, then power consumption is reduced, but flickering occurs during low-speed driving
Solution Approach 1:
The patent applies preliminary action by pre-charging the gate node of the driving transistor to a specific voltage level before low-speed driving begins. This preliminary charging ensures that when the display operates at reduced frame rates, the gate node maintains sufficient voltage to prevent flickering, while still achieving power consumption reduction through lower update frequencies.
2Measurement precision
If the vertical resolution of the display panel is increased, then image quality is improved, but the sampling time to compensate for the threshold voltage becomes insufficient
Solution Approach 1:
The patent implements preliminary action by performing threshold voltage compensation operations before the actual display frame is rendered. The gate node is pre-charged to compensate for anticipated threshold voltage variations, allowing the display to maintain accurate grayscale representation even when increased resolution reduces the available sampling time within each frame period.
3Area of stationary object
If the width of the high-potential voltage line is reduced due to larger size and higher resolution, then device integration is improved, but voltage drop increases
Solution Approach 1:
The patent introduces an intermediary element - a capacitor connected to the gate node - that mediates the voltage supply issue. This capacitor stores electrical charge and releases it when needed, compensating for voltage drops in the reduced-width high-potential voltage line. This allows the display to maintain voltage stability and reliable operation despite the reduced line dimensions required for high-resolution, large-size displays.
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.