Dual Emission Pixel Circuit for Low-Grayscale Color Shift
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Display devices experience color shift defects when driven at low grayscale levels due to unequal driving currents in emission units, leading to suboptimal luminance control.
Innovation Solution
A pixel design incorporating a driving transistor and a control transistor, along with distinct emission units, where the control transistor regulates the driving current to the emission units, ensuring different magnitudes of driving current flow through each unit, particularly at low grayscale levels, thereby mitigating color shift defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single emission unit is used with equal driving current, then the device structure is simple, but color shift defect occurs at low grayscale levels
Solution Approach 1:
The emission unit is divided into first and second emission units with different luminance characteristics. The first emission unit has higher luminance and the second emission unit has lower luminance. By segmenting the emission units and assigning different driving currents (first driving current for first emission unit, second driving current for second emission unit), the patent achieves accurate grayscale representation at low grayscale levels while maintaining a relatively simple overall structure.
2Reliability
If different driving currents are applied to emission units, then color shift defect is reduced, but device complexity increases
Solution Approach 1:
The control transistor serves multiple functions: it controls the driving current to both the first and second emission units, and its second electrode is coupled to the first electrode of the first emission unit, enabling it to regulate current distribution across different luminance units. This multi-functional design allows different driving currents to be applied to different emission units without proportionally increasing device complexity.
Data Source
AI summary
Provided herein may be a pixel. The pixel may include a driving transistor including a gate electrode coupled to a first node, a first electrode coupled to a first power line, and a second electrode coupled to a second node, a control transistor including a gate electrode coupled to the first node, a first electrode coupled to the second node, and a second electrode that is different from the first electrode, a first emission unit including at least one light-emitting element coupled between the second electrode of the control transistor and a second power line, and a second emission unit including at least one light-emitting element coupled between the second node and the second power line, wherein the second electrode of the control transistor is coupled to a first electrode of the first emission unit.