Uniform Phosphor Regions for Broad-Area Lighting Systems
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Solution Overview
Problem
The high cost and inefficiency of LED-based lighting systems, particularly in broad-area applications, due to the need for high-power LEDs, expensive thermal-management systems, and non-uniform light distribution caused by segregation of phosphor powders in binders, which affects luminous efficacy and color rendering index.
Innovation Solution
A method of forming phosphor arrangements by activating specific regions on a substrate to attract and adhere phosphor powder, transferring it to a second substrate with light-emitting elements, and using a roll-to-roll process for large-scale, uniform integration, allowing for controlled alignment and curing of phosphors with optical elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high-power LEDs are used to reduce package count, then light intensity is improved, but thermal management cost and system complexity increase
Solution Approach 1:
The invention divides the lighting system into multiple low-power LED packages distributed across the broad-area surface, rather than using fewer high-power LEDs. This segmentation allows each LED to operate at lower current levels, reducing individual heat generation and eliminating the need for complex centralized thermal management systems while maintaining overall light intensity through the distributed array arrangement.
2Illumination intensity
If phosphor powder is mixed in binder and applied to LEDs, then light conversion is achieved, but phosphor segregation occurs causing non-uniform light distribution
Solution Approach 1:
The invention extracts the phosphor powder from the binder mixture and applies it directly to the LED surfaces in pure form. This eliminates the binder medium that causes phosphor segregation during application and curing processes. The direct phosphor application ensures uniform distribution across all LED surfaces, achieving homogeneous light conversion and consistent color rendering throughout the broad-area lighting system.
3Ease of manufacture
If array of small LEDs is used over large area, then cost and efficiency losses are reduced, but manufacturing complexity increases
Solution Approach 1:
The invention performs preliminary arrangement of multiple LED packages in their final broad-area configuration before applying phosphor to each LED. This preliminary positioning ensures proper spatial distribution and alignment, simplifying the overall manufacturing process by eliminating complex post-assembly adjustments. The method also includes preliminary mixing of phosphor with binder in controlled conditions, then applying the mixture uniformly to pre-positioned LEDs, reducing manufacturing complexity while maintaining cost-effectiveness.
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 enables cost-effective, uniform, and reliable LED-based lighting systems with improved light distribution and efficiency by ensuring homogeneous phosphor coverage and alignment with light-emitting elements, reducing glare and increasing the lifespan of the lighting systems.
Implementation Method 1
A rotatable drum having a photoconductive surface... The illuminator selectively illuminates portions of the photoconductive surface as the drum rotates to render the illuminated portions attractive to the dispensed phosphor powder
Implementation Method 2
The illuminator selectively illuminates portions of the photoconductive surface as the drum rotates to render the illuminated portions attractive to the dispensed phosphor powder
Implementation Method 3
Phosphor powder is introduced to the first substrate, the phosphor powder adhering to the one or more activated regions of the first substrate
Data Source
AI summary
In accordance with certain embodiments, phosphor arrangements are formed via adhering phosphors to activated regions on a substrate and transferring them to a different substrate.