LED Package with Dual-Layer Phosphor Encapsulant
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Solution Overview
Problem
The existing LED package structures face challenges in achieving high light extraction efficiency and color rendering due to repeated absorption and release of light by phosphor materials, leading to energy depletion and suboptimal brightness.
Innovation Solution
The proposed LED package structure incorporates a dual-layer encapsulant system where the first encapsulant layer contains a phosphor with a peak emission wavelength in one range and the second encapsulant layer contains a phosphor with a peak emission wavelength in a different range, with higher concentrations at the bottom than at the top, to minimize repeated absorption and enhance wavelength conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If phosphor materials are mixed together in a single encapsulant, then the LED chip can be encapsulated with multiple phosphor types, but the light undergoes repeated absorption and release causing energy depletion and reduced light extraction efficiency
Solution Approach 1:
The single encapsulant containing multiple phosphor types is divided into multiple separate encapsulant layers, each containing a specific phosphor type. This segmentation prevents light from undergoing repeated absorption and release by different phosphor materials, thereby reducing energy loss while maintaining the ability to achieve desired color rendering through the combination of different phosphor layers.
Solution Approach 2:
The phosphor distribution is transitioned from a horizontal mixture in a single encapsulant to a vertical stratification with multiple encapsulant layers. By arranging phosphor materials in different layers along the light propagation direction, the patent eliminates repeated absorption cycles while preserving color rendering capabilities through the stacked configuration.
2Illumination intensity
If phosphor concentration is increased to improve brightness, then more light can be converted, but repeated absorption and release causes greater energy depletion
Solution Approach 1:
The high-concentration phosphor mixture is segmented into separate encapsulant layers, each with optimized phosphor concentration. This allows each layer to operate at high conversion efficiency without the cumulative energy loss that would result from multiple absorption cycles in a mixed-phosphor single encapsulant, thereby maintaining brightness while reducing energy depletion.
3Ease of manufacture
If phosphor materials are dispersed uniformly in the encapsulant, then the structure is simple to manufacture, but light undergoes multiple absorption and release cycles reducing light extraction efficiency
Solution Approach 1:
The uniform dispersion approach is segmented into multiple encapsulant layers with specific phosphor distributions. While this increases structural complexity, each layer can still be manufactured using conventional encapsulation processes, and the overall system achieves improved light extraction efficiency by eliminating repeated absorption cycles.
Solution Approach 2:
The uniform horizontal dispersion of phosphors is transformed into a vertical layered structure. This dimensional change allows light to pass through sequentially organized phosphor layers rather than undergoing random repeated absorption in a mixed medium, improving light extraction efficiency while maintaining manufacturability through established multi-layer encapsulation techniques.
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 configuration reduces energy loss, improves light extraction efficiency, and enhances the color rendering index by concentrating light energy in specific wavelength ranges, resulting in improved brightness and spectral distribution.
Implementation Method 1
fluorescent materials are widely used in the LED packaging industry to convert light emitted by chips of various specifications such as blue LED chips or ultraviolet LED chips into white light or lights of various color
Implementation Method 2
The light emitted by the LED chip can be absorbed by the phosphor material when it passes through the encapsulant and converted into light of different wavelengths and then released
Data Source
AI summary
An LED package structure with phosphor encapsulant layer includes an LED chip, a first encapsulant layer, and a second encapsulant layer; the first encapsulant layer covers the LED chip mixed with a first type phosphor having an excitation emission peak wavelength in a first wavelength range; the second encapsulant layer covers a first encapsulant layer mixed with a second type phosphor having an excitation emission peak wavelength in a second wavelength range. At least one of the first type phosphor and the second type phosphor is distributed in the corresponding first encapsulant layer or the corresponding second encapsulant layer in a state where the bottom concentration is higher than the top concentration.