Phosphor-Converted LED Color Tuning With Femtosecond Lasers
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Solution Overview
Problem
Existing LED technologies face challenges in maintaining pixel-to-pixel color uniformity and achieving accurate color distribution, particularly in micro-LEDs, which affects color and flux utilization.
Innovation Solution
The implementation of laser-modified down converter and functional materials, combined with a light blocking layer, to achieve a tuned color point distribution by modifying specific sections of the device material using femtosecond laser irradiation for ablation or roughening, thereby adjusting the color point distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional LED fabrication methods are used, then manufacturing simplicity is maintained, but color uniformity and color distribution accuracy deteriorate
Solution Approach 1:
The patent applies preliminary action by performing laser treatment on the down converter material before final LED assembly and testing. The laser modifies the material properties in advance, creating localized variations in color characteristics that will be used later for tuning the overall color distribution. This preliminary modification enables precise color control without requiring complex adjustments during final assembly.
Solution Approach 2:
The patent implements local quality by applying laser treatment to specific localized regions of the down converter material rather than uniformly treating the entire material. This creates spatially varying properties in the material, allowing different regions to contribute different color characteristics to the overall LED output, thereby achieving precise color uniformity and distribution control.
2Manufacturing precision
If laser-modified down converter material is used, then color point distribution accuracy is improved, but manufacturing complexity increases
Solution Approach 1:
The patent replaces mechanical mixing or physical sorting methods with laser-based modification. Instead of mechanically adjusting material composition or sorting LEDs by color after fabrication, the laser directly modifies the down converter material's optical properties in a controlled, non-contact manner. This substitution enables precise color point distribution control while maintaining manufacturing efficiency.
3Manufacturing precision
If conventional down converter material is used, then manufacturing process is simple, but color specification tightness deteriorates
Solution Approach 1:
The patent applies parameter changes by using laser treatment to modify the optical parameters of the down converter material. The laser alters material properties such as absorption coefficients, emission characteristics, or layer thickness in a controlled manner, enabling tight color specifications to be achieved without changing the fundamental material composition or requiring complex multi-layer structures.
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 color uniformity and flux distribution without loss, enabling tighter color specifications and improved color targeting in LED devices.
Implementation Method 1
modifying specific sections of the device material using femtosecond laser irradiation for ablation or roughening
Implementation Method 2
modifying specific sections of the device material using femtosecond laser irradiation for ablation or roughening
Implementation Method 3
The phosphor layer absorbs energy and converts an entering wavelength to a lower-energy wavelength. For example, the phosphor layer down-converts high energy LED light into a more desirable color spectrum.
Data Source
AI summary
Light sources including pluralities of light emitting diodes (LEDs) comprise primary and laser-modified device materials in order to achieve tuned color point distributions. The device materials may be down converter materials and/or functional materials. Tuned color point distributions include improved color yields by modifying sections of the device material of the LEDs that skew a baseline color point distribution. Other tuned color point distributions provide a centroid of a tuned color distribution relative to a centroid of a baseline color distribution by modifications to sections of the device material. Modifications to the device material may be conducted by femtosecond laser irradiation. Modifications to down converter materials may include ablation for thickness reduction and/or roughening for a surface topography change and/or three-dimensional shaping for light emission tunability. Modifications to functional materials may include ablation for thickness reduction.