Remote Phosphor LED Lamp with Scattering Diffuser
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Solution Overview
Problem
Conventional LED lamps face issues with heat dissipation and aesthetic concerns due to the placement of phosphor materials, leading to reduced efficiency and acceptance, especially when trying to replicate the omnidirectional emission pattern of incandescent bulbs.
Innovation Solution
The use of remote wavelength conversion materials and a separate diffusing layer in LED lamps allows for efficient heat dissipation and aesthetic masking, enabling the production of lamps with an omnidirectional emission pattern while maintaining high conversion efficiency and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If phosphor material is placed close to the LED chip, then light conversion efficiency is improved, but heat dissipation becomes difficult and phosphor degradation occurs
Solution Approach 1:
The phosphor material is segmented into multiple discrete particles distributed throughout the encapsulant rather than forming a continuous layer adjacent to the LED chip. This segmentation allows light to interact with phosphor particles from multiple directions while distributing heat generation across a larger volume, improving both conversion efficiency and thermal management.
Solution Approach 2:
The encapsulant material serves as an intermediary medium that surrounds and thermally isolates the phosphor particles from the LED chip while still allowing optical interaction. This intermediary layer facilitates heat dissipation from the phosphor while maintaining effective wavelength conversion.
2Temperature
If phosphor material is placed remotely from the LED chip, then heat dissipation is improved, but light conversion efficiency decreases
Solution Approach 1:
The phosphor particles are distributed non-uniformly within the encapsulant, with higher concentrations positioned in regions where light intensity is highest. This local quality variation ensures optimal conversion efficiency in high-flux areas while maintaining adequate thermal separation from the LED chip throughout the entire structure.
3Ease of manufacture
If conventional LED packaging is used, then manufacturing simplicity is maintained, but omnidirectional emission pattern is not achieved
Solution Approach 1:
The encapsulant structure performs multiple functions simultaneously: it provides environmental protection for the LED chip, acts as a thermal management medium, serves as the light-diffusing element, and functions as the wavelength conversion medium through embedded phosphor particles. This multi-functionality achieves omnidirectional emission while maintaining manufacturing simplicity.
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 solution results in cost-effective, reliable LED lamps that can replace traditional incandescent bulbs with improved energy efficiency and uniform light distribution, addressing heat dissipation and aesthetic concerns.
Implementation Method 1
The reflective cup may be filled with an encapsulant material 16 which may contain a wavelength conversion material such as a phosphor. Light emitted by the LED at a first wavelength may be absorbed by the phosphor, which may responsively emit light at a second wavelength.
Implementation Method 2
a separate diffusing layer which may be configured to scatter light emitted by the LED and/or the phosphor
Data Source
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AI summary
An LED lamp or bulb is disclosed that comprises a light source, a heat sink structure and an optical cavity. The optical cavity comprises a phosphor carrier having a conversions material and arranged over an opening to the cavity. The phosphor carrier comprises a thermally conductive transparent material and is thermally coupled to the heat sink structure. An LED based light source is mounted in the optical cavity remote to the phosphor carrier with light from the light source passing through the phosphor carrier. A diffuser dome is included that is mounted over the optical cavity, with light from the optical cavity passing through the diffuser dome. The properties of the diffuser, such as geometry, scattering properties of the scattering layer, surface roughness or smoothness, and spatial distribution of the scattering layer properties may be used to control various lamp properties such as color uniformity and light intensity distribution as a function of viewing angle.