Semiconductor Light-Emitting Device Reflectivity Optimization
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Solution Overview
Problem
Current white light-emitting diodes (WLEDs) with a two-wavelength configuration, using a blue-light LED chip and yellow inorganic fluorescent powder, suffer from lower light-emitting efficiency and poorer color rendering properties compared to three-wavelength WLEDs, necessitating an improvement in their performance.
Innovation Solution
A semiconductor light-emitting device is designed with a substrate, multi-layer structure, and a light reflector assembly that includes alternating layers of high and low refractive index materials to enhance light reflectivity and efficiency, allowing for better color rendering by optimizing the reflectivity of red, green, and blue lights, and potentially incorporating a fluorescent layer for improved excitation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a two-wavelength WLED configuration (blue LED chip + yellow fluorescent powder) is used, then fabrication cost is reduced and ease of manufacture is improved, but light-emitting efficiency and color rendering property deteriorate
Solution Approach 1:
The patent segments the yellow fluorescent powder into multiple wavelength-specific fluorescent materials (red, green, blue-green) that can be independently optimized. This allows each fluorescent component to be tailored for maximum efficiency at its specific wavelength while maintaining the simple two-chip structure, thus resolving the contradiction between ease of manufacture and light-emitting efficiency
Solution Approach 2:
The patent uses composite fluorescent materials comprising multiple types of fluorescent powders with different emission characteristics. This composite approach enables the yellow fluorescent layer to convert blue light into multiple wavelength components (red, green, blue-green) simultaneously, improving overall light-emitting efficiency while maintaining the simple two-wavelength WLED structure
2Ease of manufacture
If a two-wavelength WLED configuration (blue LED chip + yellow fluorescent powder) is used, then fabrication cost is reduced, but color rendering property deteriorates
Solution Approach 1:
The patent segments the broad yellow emission into multiple discrete wavelength bands by using separate fluorescent materials for red, green, and blue-green regions. This segmentation allows each color component to be independently optimized for its specific wavelength range, significantly improving color rendering properties while maintaining the cost-effective two-chip architecture
Solution Approach 2:
The patent applies local quality by assigning different fluorescent materials to specific wavelength regions within the yellow band. Each fluorescent material is selected and positioned to optimize emission in its specific wavelength range (red for 610-680nm, green for 520-560nm, blue-green for 470-495nm), thereby improving overall color rendering while maintaining fabrication simplicity
3Use of energy by moving object
If multiple single-colored LED chips are used to create three-wavelength WLED, then color rendering property and light-emitting efficiency are improved, but fabrication cost increases
Solution Approach 1:
The patent extracts the need for multiple LED chips by retaining only the blue LED chip and performing the wavelength conversion function through fluorescent materials. This extraction eliminates the complexity and cost of integrating multiple LED chips while maintaining the light-emitting efficiency benefits through optimized fluorescent conversion
Solution Approach 2:
The patent introduces fluorescent materials as intermediaries between the blue LED chip and the final multi-wavelength output. These fluorescent materials act as mediators that convert blue light into multiple wavelength components (red, green, blue-green), achieving three-wavelength functionality without requiring three separate LED chips, thus reducing fabrication cost while maintaining light-emitting efficiency
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 semiconductor light-emitting device increases light-emitting efficiency and color rendering properties by adjusting the reflectivity of different wavelengths, thereby enhancing the performance of WLEDs without increasing the quantity of fluorescent powders, thus offering a more efficient and effective white light emission.
Implementation Method 1
a light reflector assembly that includes alternating layers of high and low refractive index materials to enhance light reflectivity
Implementation Method 2
a light reflector assembly that includes alternating layers of high and low refractive index materials to enhance light reflectivity
Implementation Method 3
uses a blue-light LED chip combined with a yellow inorganic fluorescent powder (or a yellow organic fluorescent dye) to emit white light. The blue light emitted from a blue-light LED chip has a wavelength between 440 nm and 490 nm. After being illuminated by the blue light, the yellow inorganic fluorescent powder can emit yellow-colored fluorescence
Data Source
AI summary
The invention discloses a semiconductor light-emitting device. The semiconductor light-emitting device according to the invention includes a substrate, a multi-layer structure, at least one electrode structure, and a light reflector. The substrate has an upper surface. The multi-layer structure is formed on the upper surface of the substrate. The multi-layer structure includes a light-emitting region and at least one semiconductor material layer. The multi-layer structure also has a top surface. The at least one electrode structure is formed on the top surface of the multi-layer structure. The light reflector is formed on the top surface of the multi-layer structure.