Crystalline Phosphor Substrates for High-Efficiency White Light
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Solution Overview
Problem
Existing methods for manufacturing down-conversion substrates for LEDs are limited in producing a multitude of individual wavelengths and often result in reduced light efficiency due to the use of powder-based phosphors, which are not optically transparent and have optical discontinuities, while epitaxial technologies are costly and difficult to scale for high-volume production.
Innovation Solution
A method involving the formation of crystallographic layers with phosphor materials and activators, grown as single crystallographic phase substrates, allowing for the production of down-converting substrates that are optically transparent, capable of emitting a full spectrum of white light and polarized light, with the ability to tune emission wavelengths and spectral width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If powder-based phosphors are used for down-conversion, then manufacturing cost is reduced, but light extraction efficiency decreases due to optical discontinuities and lack of transparency
Solution Approach 1:
The invention changes the physical state of phosphor materials from powder form to crystalline form. This parameter change eliminates optical discontinuities and enables optical transparency, thereby improving light extraction efficiency while maintaining manufacturing feasibility through crystal growth processes
Solution Approach 2:
The invention creates composite crystalline structures that integrate phosphor materials into a continuous crystalline matrix. This composite approach eliminates the need for binder materials with mismatched refractive indices, resolving the optical discontinuities that plague powder-based phosphors while maintaining cost-effectiveness
2Adaptability or versatility
If epitaxial technology is used to produce substrates capable of emitting multiple wavelengths, then wavelength diversity is improved, but manufacturing cost and complexity increase significantly
Solution Approach 1:
The invention segments the down-conversion function into multiple crystalline layers, each layer responsible for specific wavelength conversions. This segmentation approach enables multiple wavelength emissions while using simpler crystal growth techniques rather than complex epitaxial processes, thereby reducing manufacturing complexity
Solution Approach 2:
The invention uses crystalline phosphor layers as intermediary materials that convert primary LED emission wavelengths into multiple secondary wavelengths. This intermediary approach achieves wavelength diversity through material selection rather than complex device structures, reducing overall system complexity
3Ease of manufacture
If powder-based phosphors with binder materials are used, then manufacturing is simplified, but optical transparency is lost due to refractive index mismatch
Solution Approach 1:
The invention changes the structural organization of phosphor materials from discrete powder particles bound together to a continuous crystalline structure. This parameter change eliminates refractive index mismatch issues inherent in binder materials, achieving optical transparency while maintaining manufacturing simplicity through crystal growth processes
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
Enables the production of high-efficiency, high-flux LEDs with a wide spectral range, capable of producing white light and individual wavelengths, while maintaining optical transparency and reducing manufacturing costs, thus improving color rendering and light quality.
Implementation Method 1
conversion of primary emissions of the LED to longer wavelengths is commonly referred to as down-conversion of the primary emission
Implementation Method 2
heating the crystallography layer at high temperature to promote crystal growth in the crystallography layer
Data Source
AI summary
A method of manufacturing a down-conversion substrate for use in a light system includes forming a first crystallography layer including one or more phosphor materials and, optionally, applying at least one activator to the crystallography layer, heating the crystallography layer at high temperature to promote crystal growth in the crystallography layer, and drawing out the crystallography layer and allowing the crystallography layer to cool to form the down-conversion substrate. A light system includes an excitation source for emitting short wavelength primary emissions; and a down-conversion substrate disposed in the path of at least some of the primary emissions from the excitation source to convert at least a portion of the primary emissions into longer-wavelength secondary emissions, wherein the substrate includes one or more crystallography layers, wherein each crystallography layer includes one or more phosphor materials, and optionally at least one activator. Down-converted secondary light may be produced by the system.