Sub-pixel Luminous Area Adjustment for LED Color Uniformity
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Solution Overview
Problem
The uneven epitaxial quality of semiconductor layers in LEDs leads to deviations in peak wavelengths of light emitted, causing color discrepancies in LEDs initially intended to emit the same color, which affects image quality and production yield in display devices.
Innovation Solution
The display device incorporates sub pixel units from sub epitaxial structures with adjusted luminous areas to ensure that the difference in electroluminescent wavelengths between sub pixel units is less than or equal to 2 nm, achieving uniform color emission by calibrating the luminous areas based on photoluminescence measurement results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LEDs are produced using the same epitaxial wafer without additional classification, then manufacturing efficiency is improved, but color uniformity deteriorates due to uneven epitaxial quality
Solution Approach 1:
The patent applies local quality by adjusting the luminous area of individual sub-pixel units based on their specific epitaxial quality characteristics. Each sub-pixel unit's luminous area is customized to compensate for local variations in epitaxial quality, ensuring uniform color emission across the display device while maintaining efficient mass production from a single epitaxial wafer.
2Volume of moving object
If LED size is reduced to micrometer scale, then device miniaturization is improved, but color consistency deteriorates due to increased sensitivity to epitaxial quality variations
Solution Approach 1:
The patent applies parameter changes by adjusting the luminous area parameter of sub-pixel units to compensate for color deviations caused by epitaxial quality variations. By modifying the luminous area parameter rather than the physical size of the LEDs, the system achieves color consistency across micrometer-scale LEDs while maintaining the benefits of miniaturization.
3Manufacturing precision
If sub-pixel units have different luminous areas, then color uniformity is improved, but device complexity increases due to additional calibration requirements
Solution Approach 1:
The patent applies preliminary action by pre-calibrating and determining the optimal luminous area for each sub-pixel unit before final assembly. The luminous area of each sub-pixel unit is predetermined based on epitaxial quality measurements, allowing the system to achieve color uniformity without requiring complex real-time calibration during operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the display quality and visual experience by ensuring uniform color emission across sub pixel units, improving the yield rate and resolution of the display device.
Implementation Method 1
The first sub pixel unit is from a sub epitaxial structure emitting light within a first photoluminescent wavelength, the second sub pixel unit is from a sub epitaxial structure emitting light within a second photoluminescent wavelength
Implementation Method 2
The difference between a first electroluminescent wavelength of the first sub pixel unit and a second electroluminescent wavelength of the second sub pixel unit is less than or equal to 2 nm
Data Source
AI summary
Disclosed are an epitaxial wafer and a display device that includes a display substrate, a first sub pixel unit and a second sub pixel unit. The first sub pixel unit has a first luminous area, and the second sub pixel unit has a second luminous area different from the first luminous area. The first sub pixel unit and the second sub pixel unit belong to the same color type and are located in different pixel units. The first sub pixel unit is a sub epitaxial structure emitting light within a first photoluminescent wavelength, the second sub pixel unit is a sub epitaxial structure emitting light within a second photoluminescent wavelength, and the first photoluminescent wavelength is different from the second photoluminescent wavelength. The difference between electroluminescent wavelengths of the first sub pixel unit and the second sub pixel unit is less than or equal to 2 nm.