Surface-Emitting Light Source Layout for Higher Light Extraction
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Solution Overview
Problem
Existing light-emitting devices with wavelength converting materials have low light-extraction efficiency.
Innovation Solution
A light-emitting device configuration comprising a light-emitting element, first and second wavelength converting members, and a first light-transmissive member, where the refractive index of the transmissive member is lower than the base materials of the converting members, and the light-emitting surfaces form a continuous emission surface, enhancing light extraction through refractive index differences and reduced scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If wavelength converting members are used in light-emitting devices, then light emission at different wavelengths is achieved, but light-extraction efficiency deteriorates
Solution Approach 1:
The device segments the wavelength conversion function into multiple independent wavelength converting members, each containing different wavelength converting materials. This segmentation allows each member to be optimized for specific wavelength conversion while reducing overall light scattering and absorption losses, thereby improving light-extraction efficiency while maintaining diverse wavelength emission.
Solution Approach 2:
A light-transmissive member with a refractive index lower than the base materials of the wavelength converting members is introduced as an intermediary component. This intermediary reduces light scattering at interfaces and improves light extraction from the wavelength converting members, effectively resolving the contradiction between wavelength conversion capability and light-extraction efficiency.
2Illumination intensity
If multiple wavelength converting members are stacked, then broader spectrum light emission is achieved, but light scattering and absorption increase
Solution Approach 1:
The light-transmissive member with lower refractive index serves as an intermediary between stacked wavelength converting members, reducing interface reflections and scattering. This allows multiple wavelength converting members to be stacked for broader spectrum emission while minimizing the harmful light scattering and absorption that would otherwise increase with each additional layer.
Solution Approach 2:
The refractive index parameter of the light-transmissive member is specifically selected to be lower than the base materials of the wavelength converting members. This parameter change optimizes light transmission through the stacked structure, reducing scattering and absorption losses while enabling broader spectrum emission through multiple wavelength converting members.
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 configuration achieves high light extraction efficiency by minimizing scattering and optimizing light emission from lateral surfaces, resulting in improved light distribution and reduced absorption, thereby enhancing the overall light output.
Implementation Method 1
The first wavelength converting material is configured to absorb a portion of the first light and emit a second light
Implementation Method 2
The first wavelength converting material is configured to absorb a portion of the first light and emit a second light. The second light has a second peak wavelength that is different from the first peak wavelength
Implementation Method 3
The second wavelength converting material is configured to absorb a portion of the first light and emit a third light
Implementation Method 4
The second wavelength converting material is configured to absorb a portion of the first light and emit a third light. The third light has a third peak wavelength that is different from the first peak wavelength and the second peak wavelength
Implementation Method 5
A refractive index of the first light-transmissive member is smaller than a refractive index of the first base material and the second peak wavelength is shorter than the third peak wavelength
Implementation Method 6
enhancing light extraction through refractive index differences and reduced scattering
Data Source
AI summary
A light-emitting device includes a light-emitting element, a first wavelength converting member, a second wavelength converting member, and a first light-transmissive member. The first light-transmissive member is located between the first wavelength converting member and the second wavelength converting member. The first light-transmissive member has a refractive index smaller than a refractive index of a base material of the one of the first wavelength converting member and the second wavelength converting member having a shorter peak emission wavelength than the other of the first wavelength converting member and the second wavelength converting member. Each of corresponding surfaces of lateral surfaces of the first wavelength converting member, lateral surfaces of the first light-transmissive member, and lateral surfaces of the second wavelength converting member may constitute a continuous light-emission surface.