LED Package Structure with Dual Wavelength Conversion Layers
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Solution Overview
Problem
Conventional LED illumination devices have limitations in brightness and luminous efficiency due to suboptimal phosphor excitation, leading to reduced color rendering index and brightness of white light.
Innovation Solution
The LED package structure employs a light-emitting array with non-secondarily excited first and second light-emitting units, each with a specific wavelength conversion layer, generating distinct light beams that are mixed to produce white light, utilizing single-color phosphors to enhance phosphor excitation efficiency and achieve higher brightness and color rendering index.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional phosphor mixing methods are used to generate white light, then the device complexity is reduced, but the brightness and color rendering index deteriorate
Solution Approach 1:
The patent divides the white light generation into two separate segments: first light-emitting units with first wavelength conversion layer generating first light beam, and second light-emitting units with second wavelength conversion layer generating second light beam. This segmentation allows each phosphor layer to be optimized independently, avoiding the excitation efficiency losses that occur in conventional mixed phosphor systems where multiple phosphors compete for excitation energy.
Solution Approach 2:
The patent applies local quality by assigning different wavelength conversion characteristics to different spatial locations. The first wavelength conversion layer uses phosphors with specific excitation and emission characteristics, while the second wavelength conversion layer uses phosphors with different characteristics. This local optimization ensures that each phosphor operates in its optimal excitation range, maximizing overall conversion efficiency and brightness.
2Productivity
If conventional mixed phosphors are used, then the manufacturing process is simplified, but the phosphor excitation efficiency deteriorates
Solution Approach 1:
The manufacturing process is segmented into two independent production lines: one for first light-emitting units with first wavelength conversion layer, and another for second light-emitting units with second wavelength conversion layer. This segmentation allows each phosphor type to be manufactured and optimized independently, improving excitation efficiency while maintaining manufacturing simplicity through modular assembly.
Solution Approach 2:
The patent changes the key parameter of phosphor excitation wavelength by using two distinct wavelength conversion layers with different phosphor materials. The first wavelength conversion layer uses phosphors excited at one wavelength range, while the second uses phosphors excited at a different wavelength range. This parameter differentiation eliminates excitation competition and maximizes overall phosphor excitation efficiency.
3Illumination intensity
If blue LED with yellow phosphor is used for white light generation, then the device structure is simplified, but the color rendering index and brightness are insufficient
Solution Approach 1:
The patent segments the white light generation into two distinct light-emitting units, each with its own wavelength conversion layer. The first light-emitting units generate first light beam with specific spectral characteristics, and the second light-emitting units generate second light beam with complementary spectral characteristics. This segmentation enables superior color rendering index and brightness by ensuring complete and efficient spectral coverage.
Solution Approach 2:
The patent uses composite phosphor materials in the two wavelength conversion layers. The first wavelength conversion layer employs phosphors with specific emission characteristics, while the second wavelength conversion layer employs phosphors with complementary emission characteristics. This composite approach creates a synergistic effect that achieves high color rendering index and brightness, overcoming the limitations of single-phosphor systems.
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 results in white light with improved brightness and color rendering index, surpassing conventional methods by increasing the proportion of green light and optimizing the ratio of emission lights to achieve a color rendering index of at least 90 and a 10-12% boost in brightness.
Implementation Method 1
Each of the first light-emitting units includes a first light-emitting chip and a first wavelength conversion layer covering the first light-emitting chip... The first light beam includes a first emission light generated by exciting the first wavelength conversion layer
Data Source
AI summary
An LED package structure includes a substrate and a light-emitting array. The substrate has a die bond area, and the light-emitting array is disposed in the die bond area. Each first light-emitting unit of the light-emitting array includes a first light-emitting chip and a first wavelength conversion layer of the light-emitting chip, each second light-emitting unit of the light-emitting array includes a second light-emitting chip and a second wavelength conversion layer covering the second light-emitting chip. A first light beam includes a first emission light generated by exciting the first wavelength conversion layer, and the second light beam includes a second emission light generated by exciting the second wavelength conversion layer, and the difference between the first and second emission light peak wavelengths is at least 30 nm.