Display Panel Pixel Bias Adjustment for Flicker-Free Emission
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Solution Overview
Problem
Display panels experience flickering issues due to bias problems in light emitting elements, particularly when light emitting elements with different areas have inaccurate driving currents and threshold voltage deviations, leading to non-uniform light emission and flickering.
Innovation Solution
The display panel incorporates pixel circuits with bias adjustment signals tailored to individual light emitting elements, adjusting the bias states of driving transistors based on the area and channel width-to-length ratio of the transistors to stabilize the driving current and prevent flickering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If light emitting elements with different areas are driven with the same driving current, then the display panel structure is simple, but the light emission becomes non-uniform and flickering occurs
Solution Approach 1:
The patent applies local quality by providing different bias adjustment signals to pixel circuits based on the area of their corresponding light emitting elements. Specifically, pixel circuits driving light emitting elements with larger areas receive different bias adjustment signals compared to those driving smaller elements, thereby achieving uniform light emission across different areas while maintaining a relatively simple overall structure
Solution Approach 2:
The patent changes the bias state parameter of the driving transistor through bias adjustment signals. By dynamically adjusting the bias state according to the area of the light emitting element, the system optimizes the driving current characteristics to achieve uniform light emission, transforming a static driving approach into a dynamic parameter-adjustment approach
2Reliability
If bias adjustment signals are applied to all pixel circuits, then light emission uniformity is improved, but the device complexity increases
Solution Approach 1:
The patent segments the pixel circuits into different groups based on the area of their corresponding light emitting elements. By dividing the display panel into regions with different element areas and applying tailored bias adjustment signals to each segment, the system achieves uniform light emission while managing complexity through structured segmentation rather than treating all pixel circuits uniformly
3Illumination intensity
If the driving current is increased for larger light emitting elements, then the light emission brightness is improved, but the threshold voltage deviation increases and flickering worsens
Solution Approach 1:
The patent implements feedback by using bias adjustment signals that are determined based on the area of the light emitting element. This feedback mechanism allows the system to automatically adjust the bias state of the driving transistor to compensate for threshold voltage deviations that occur with higher driving currents, thereby maintaining uniform brightness while reducing flickering across different element sizes
Data Source
AI summary
A display panel includes: a light emitting element including a first light emitting element and a second light emitting element; and a pixel circuit including a first pixel circuit and a second pixel circuit. The first and second pixel circuits are respectively connected to the first and second light emitting elements. The pixel circuit is configured to receive a bias adjustment signal including a first bias adjustment signal and a second bias adjustment signal, and the first and second pixel circuits are respectively configured to receive the first and second bias adjustment signals. Areas of the first and second light emitting elements are respectively S1 and S2, and voltage values of the first and second bias adjustment signals are V1 and V2, where (S1−S2)×(|V1|−|V2|)≠0. A display device including the display panel is also provided.