Engineered Phosphor LED Packages for Uniform Color
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Solution Overview
Problem
Conventional phosphor-converted LEDs suffer from angularly dependent color non-uniformity, requiring additional elements like diffusers or mixing chambers to achieve uniform color distribution, which increases cost, bulk, and reduces efficiency.
Innovation Solution
Engineered phosphor distributions within a binder on the LED die, using gradients and distinct regions of phosphor particles, and applying non-neutral-gravity settling forces to redistribute phosphor particles, ensuring uniform color distribution and high extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional phosphor-converted LEDs are used with uniform phosphor distribution, then the structure is simple and cost-effective, but the color distribution is non-uniform across different viewing angles
Solution Approach 1:
The patent applies local quality by creating non-uniform phosphor distributions with specific concentration gradients and distinct regions (high-concentration and low-concentration areas) within the binder. This engineered local variation in phosphor density across different zones of the LED package enables uniform color distribution across viewing angles, resolving the contradiction between manufacturing simplicity and color uniformity.
2Manufacturing precision
If additional elements like diffusers or mixing chambers are added to achieve uniform color distribution, then color uniformity is improved, but cost, bulk, and complexity increase
Solution Approach 1:
The patent extracts the color-uniformity function from separate optical components (diffusers, mixing chambers) and integrates it directly into the phosphor-binder structure on the LED die. By embedding the uniforming function within the phosphor distribution pattern itself, the invention eliminates the need for additional optical elements, thereby reducing cost, bulk, and device complexity while maintaining color uniformity.
Solution Approach 2:
The patent merges the color conversion function and the color uniformity function into a single integrated phosphor-binder structure. The engineered phosphor distribution simultaneously performs wavelength conversion and angular color uniformity correction, consolidating multiple functions into one component and eliminating the need for separate diffusers or mixing chambers.
3Manufacturing precision
If additional elements like diffusers or mixing chambers are added to achieve uniform color distribution, then color uniformity is improved, but extraction efficiency is reduced
Solution Approach 1:
The patent extracts the color-uniformity function from separate optical components that would impede light extraction and integrates it into the phosphor-binder structure. This eliminates the need for additional optical elements that cause light scattering and absorption losses, thereby maintaining high extraction efficiency while achieving uniform color distribution.
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
The solution achieves uniform color distribution and high extraction efficiency by creating controlled phosphor particle gradients and distributions, reducing the need for additional components and maintaining light intensity patterns.
Implementation Method 1
wavelength-conversion particles for absorbing at least a portion of light emitted from the light-emitting die and emitting converted light having a different wavelength
Implementation Method 2
light-conversion materials such as phosphors... wavelength-conversion element (WCE) generates white light by combining the short-wavelength radiant flux (e.g., blue light) emitted by the semiconductor LED with long-wavelength radiant flux (e.g., yellow light) emitted by, for example one or more phosphors within the WCE
Implementation Method 3
applying non-neutral-gravity settling forces to redistribute phosphor particles
Implementation Method 4
A non-neutral-gravity settling force is applied to the wavelength-conversion particles, whereby the wavelength-conversion particles form a predetermined concentration gradient of wavelength-conversion particles in at least a portion of the binder
Data Source
AI summary
In accordance with certain embodiments, regions of spatially varying wavelength-conversion particle concentration are formed over light-emitting dies.