LED Phosphor Encapsulation for Fewer Bins and Uniform Color
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Solution Overview
Problem
Conventional LED manufacturers face challenges in reducing the number of bins during production due to variations in LED chip production, leading to non-uniformity in display panels when LEDs from different bins are used.
Innovation Solution
The use of visible and non-visible light converting phosphors in LED packages, which allows for the encapsulation of LED chips to achieve specific light output intensities and color coordinates, enabling categorization into fewer bins by converting light wavelengths and intensities through mathematical relationships and correlations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple bins are used to categorize LEDs during production, then manufacturing precision of individual bins is improved, but device complexity and production efficiency deteriorate
Solution Approach 1:
The patent applies parameter changes by adjusting the phosphor conversion layer properties (composition, thickness, particle size distribution) to shift the LED output spectrum. This allows LEDs with different initial chip characteristics to be converted to uniform output parameters, reducing the number of bins needed while maintaining manufacturing precision.
Solution Approach 2:
The patent uses composite phosphor materials combining multiple phosphor types (e.g., yellow phosphor + red phosphor + green phosphor) to achieve broader and more uniform spectral coverage. This composite approach enables a single bin to cover a wider range of output characteristics, reducing overall binning complexity.
2Productivity
If LEDs from different bins are used in display panels, then productivity is improved, but uniformity and reliability deteriorate
Solution Approach 1:
By changing the phosphor conversion parameters (composition ratios, layer thickness), the patent compensates for variations in LED chip characteristics. This allows display panels to use LEDs from broader bin ranges while maintaining uniform color and brightness output, improving productivity without sacrificing reliability.
3Manufacturing precision
If conventional binning processes are used, then manufacturing precision is maintained, but loss of time and productivity deteriorate
Solution Approach 1:
The patent performs preliminary spectral characterization of LED chips during manufacturing and uses this data to predict the optimal phosphor conversion parameters needed. This preliminary action allows for streamlined binning processes, reducing sorting time while maintaining precision by pre-identifying which chips can be grouped together with specific phosphor conversions.
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 allows for the reduction of LED bins by controlling light output intensity and color, ensuring uniformity in display panels and improving the efficiency of the binning process.
Implementation Method 1
combining visible and non-visible light converting phosphor
Data Source
AI summary
Lighting systems and methods of combining visible and non-visible light converting phosphor are presented herein. A method comprises varying respective amounts of a non-visible light converting phosphor and respective amounts of a visible light converting phosphor that are included in respective encapsulants that have been used to encapsulate LED chips of respective samples of a group of LED chips within respective LED test packages; based on determined mathematical relationships and correlations associated with the varying, including a first amount of the non-visible light converting phosphor and a second amount of the visible light converting phosphor in an encapsulant; and encapsulating, using the encapsulant, a manufacturing portion of the group of LED chips within respective LED packages to facilitate categorization of the respective LED packages into a manufacturing bin represented by a defined target LED package light output intensity and a defined target LED package light output color coordinate.