Remote Phosphor Light Device with Recessed Extractor
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Solution Overview
Problem
Conventional white LEDs face challenges such as light-energy losses, phosphor self-heating, and undesired light propagation due to the properties of luminescent materials, which affect their efficiency and durability.
Innovation Solution
A light-emitting device design featuring a solid state light-emitting element, a remote phosphor element, and an extractor element, where the phosphor element converts and scatters light, and the extractor element is positioned to minimize losses by using refractive index mismatches and a recessed configuration to redirect scattered light efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the phosphor element is positioned close to the LED pump for efficient light conversion, then the device complexity is reduced, but light-energy losses increase due to phosphor self-heating and absorption
Solution Approach 1:
The phosphor element is extracted from the immediate vicinity of the LED pump and positioned remotely within the enclosure. This separation allows the phosphor to convert pump light more efficiently without excessive self-heating and absorption losses, while the enclosure maintains optical coupling between the components
Solution Approach 2:
The enclosure acts as an intermediary optical medium between the LED pump and phosphor element. It facilitates light transmission and coupling while allowing the phosphor to be positioned optimally for conversion efficiency without direct contact with the heat-generating LED pump
2Power
If the phosphor element converts pump light efficiently, then luminous efficacy is improved, but phosphor self-heating from Stokes loss increases causing degradation
Solution Approach 1:
The phosphor element is positioned remotely from the LED pump, extracting it from the high-temperature zone. This spatial separation enables efficient light conversion while reducing thermal load on the phosphor, preventing degradation from self-heating
Solution Approach 2:
The enclosure is designed to manage and utilize the thermal characteristics of the system. By controlling the optical and thermal environment within the enclosure, the design converts potential harmful heat into manageable thermal conditions that maintain phosphor performance
3Loss of energy
If the phosphor element is remote from the light-emitting element, then light losses are reduced, but device complexity increases due to additional structural components
Solution Approach 1:
The enclosure serves multiple functions simultaneously: it provides structural support for the remote phosphor positioning, acts as an optical medium for light transmission and coupling, and manages thermal conditions. This multi-functionality reduces the need for additional separate components
4Productivity
If the extractor element maximizes forward transmission, then light output efficiency is improved, but light propagation control becomes more difficult
Solution Approach 1:
The extractor element features localized optical properties with different refractive indices in different regions. This allows selective control of light propagation - maximizing forward transmission in certain directions while maintaining control over overall light distribution patterns
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 design reduces light absorption losses and enhances the propagation of scattered light, improving the efficiency and durability of white LEDs by minimizing backscattered light absorption and promoting forward light transmission.
Implementation Method 1
a phosphor element configured to convert pump light to converted light and to scatter non-converted pump light
Implementation Method 2
a phosphor element configured to convert pump light to converted light and to scatter non-converted pump light
Implementation Method 3
the phosphor element comprises a material having a first refractive index n1, where n01, and the transparent material has a refractive index n2, where n02
Implementation Method 4
the exit surface is shaped and positioned such that an angle of incidence on the exit surface of the scattered light from the region of contact that directly impinges on the exit surface is less than the critical angle for total internal reflection
Data Source
AI summary
A variety of light-emitting devices are disclosed that are configured to output light provided by a light-emitting element (LEE). In general, embodiments of the light-emitting devices feature a light-emitting element disposed in a recess, a scattering element that is spaced apart from the light-emitting element and an extractor element coupled to the scattering element.