Nanostructured Phosphor LED with Remote Packaging
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Solution Overview
Problem
Current semiconductor light-emitting devices with wavelength converting materials face inefficiencies due to red-emitting phosphors emitting light outside the human eye-response curve and excessive scattering, leading to reduced efficiency in light emission.
Innovation Solution
Incorporation of nanostructured phosphors with a high surface area-to-volume ratio, specifically quantum dots or doped dots, that emit light in a narrow wavelength band and are designed to minimize scattering, combined with a packaging solution that efficiently removes heat and protects the materials from oxygen and moisture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If red-emitting phosphors are used for wavelength conversion, then the device can emit light in the red region, but the emitted light falls outside the human eye-response curve causing reduced efficiency
Solution Approach 1:
The patent changes the physical parameters of the phosphor material by reducing particle size to the nanoscale (1-100 nm), which fundamentally alters the emission characteristics. This parameter change enables the phosphor to emit light within the human eye-response curve while maintaining red-region wavelength conversion capability, thereby resolving the contradiction between light emission efficiency and energy loss.
2Device complexity
If conventional phosphor materials are used, then the device structure is simple, but excessive scattering occurs leading to reduced light emission efficiency
Solution Approach 1:
The patent applies parameter changes by transitioning from conventional micrometer-scale phosphor particles to nanoscale particles (1-100 nm). This size parameter change dramatically reduces light scattering while maintaining the phosphor's wavelength conversion function, thereby improving light emission efficiency without significantly complicating the device structure.
3Illumination intensity
If nanostructured phosphors with high surface area-to-volume ratio are used, then light emission efficiency is enhanced, but the material becomes more sensitive to oxygen and moisture requiring protective packaging
Solution Approach 1:
The patent introduces an intermediary protective layer or encapsulation structure that isolates the nanostructured phosphor from oxygen and moisture environments. This intermediary protection allows the phosphor to maintain its high surface area-to-volume ratio and superior light emission efficiency while preventing degradation from environmental exposure, thereby resolving the reliability issue.
4Use of energy by moving object
If wavelength converting materials are placed close to the light emitting region, then the conversion efficiency is high, but heat accumulation occurs reducing overall device performance
Solution Approach 1:
The patent changes the thermal parameters of the system by introducing high thermal conductivity substrates or heat sink structures adjacent to the phosphor layer. This thermal parameter management allows the wavelength converting materials to be positioned close to the light emitting region for high conversion efficiency while actively managing heat accumulation through enhanced thermal conduction pathways.
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 use of nanostructured phosphors enhances light emission efficiency by confining light emission within the human eye-response curve and reducing scattering, while the packaging solution maintains optical and chemical stability, thereby improving the overall performance of the light-emitting device.
Implementation Method 1
Wavelength converting materials absorb light emitted by the light emitting region of the III-nitride device and emit light of a different, longer wavelength
Implementation Method 2
nanostructured phosphors with a high surface area-to-volume ratio, specifically quantum dots or doped dots, that emit light in a narrow wavelength band and are designed to minimize scattering
Data Source
Figure 1~3B
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Figure 7~8
AI summary
Embodiments of the invention include a light emitting device (LED 10), a first wavelength converting material (13, in a matrix 14 to form a layer 12), and a second wavelength converting material (forming layer 16). The first wavelength converting material includes a nanostructured wavelength converting material. The nanostructured wavelength converting material includes particles having at least one dimension that is no more than 100 nm in length. The first wavelength converting material (13) is spaced apart from the light emitting device (10).