Phosphor-Converted LED With Interference Filter Blocking Layer
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Solution Overview
Problem
Phosphor-converted light-emitting devices face inefficiencies due to a small fraction of initial radiation being converted, leading to interference from undesired wavelengths, which can be mitigated by using filters but still affects the application of the converted radiation.
Innovation Solution
Incorporating a blocking layer, such as an interference filter or Bragg mirror, between the emitter device and the conversion layer to attenuate unwanted electromagnetic radiation and enhance the intensity of the desired converted spectrum, potentially including a metal layer and a transparent carrier or housing configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a blocking layer is added to attenuate unwanted radiation, then spectral purity is improved, but device complexity increases
Solution Approach 1:
An interference filter is introduced as an intermediary component between the phosphor conversion layer and the output. This filter selectively transmits desired wavelengths while blocking unwanted radiation, thereby improving spectral purity without requiring fundamental changes to the LED structure itself
Solution Approach 2:
The interference filter is constructed using composite dielectric layers with different refractive indices. These multiple layers work together through optical interference to achieve selective wavelength transmission, combining multiple materials to solve the spectral purity problem
2Manufacturing precision
If filters are used to absorb undesired wavelengths, then spectral purity is improved, but energy loss increases
Solution Approach 1:
Instead of simply absorbing unwanted wavelengths (which wastes energy), the interference filter reflects undesired wavelengths back through the phosphor conversion layer. This allows the phosphor to potentially re-convert the reflected light, transforming what would be wasted energy into useful output
Solution Approach 2:
The interference filter creates an optical feedback path by reflecting unwanted wavelengths back toward the phosphor conversion layer. This feedback mechanism allows the system to reuse radiation that would otherwise be lost, improving overall energy efficiency while maintaining spectral purity
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 blocking layer effectively reduces unwanted radiation, enhancing the output in the desired spectrum range, particularly beneficial for near-infrared applications by improving the conversion efficiency and spectral purity.
Implementation Method 1
a conversion layer (2) comprising at least one phosphor, and configured to convert electromagnetic radiation of the spectrum into electromagnetic radiation of a different further spectrum
Implementation Method 2
An interference filter is formed by a plurality of thin layers of dielectric materials having different refractive indices. Owing to constructive and destructive interference at these layers, larger or smaller fractions of incident electromagnetic radiation are transmitted and reflected
Implementation Method 3
The blocking layer reflects electromagnetic radiation emitted by the emitter device to the conversion layer and thus enhances an intensity of electromagnetic radiation of the further spectrum
Data Source
AI summary
A phosphor-converted light-emitting device comprising an emitter device configured to emit a spectrum of electromagnetic radiation, a conversion layer comprising at least one phosphor, the conversion layer being configured to convert electromagnetic radiation of the spectrum into electromagnetic radiation of a different further spectrum, and a blocking layer configured to attenuate electromagnetic radiation outside the further spectrum, the conversion layer being arranged between the emitter device and the blocking layer.