Ceramic Optical Conversion Layer for Heat-Stable LED Phosphor Mixing
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Solution Overview
Problem
Conventional lighting apparatuses with multi-layered optical conversion layers have complex structures and suffer from deteriorated optical efficiency due to resin degradation at high temperatures, necessitating a simpler and thermally stable solution.
Innovation Solution
A lighting apparatus with a ceramic optical conversion layer comprising mixed crystal grains of first and second phosphors (SrSi2O2N2 and Sr2Si5N8) that are mixed without resin, formed through ball-milling and heat treatment, allowing for a uniform or non-uniform thickness and surface gradient to enhance durability and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a multi-layered optical conversion layer structure is used to convert light wavelength, then various phosphors can be used to convert light, but the shape of the optical conversion layer becomes complicated
Solution Approach 1:
The patent combines multiple phosphor types (first phosphor and second phosphor) into a single optical conversion layer, replacing the conventional multi-layered structure. This merging approach maintains the light wavelength conversion capability while simplifying the overall structure by eliminating the need for separate layers for each phosphor type.
2Ease of manufacture
If resin is used in the optical conversion layer, then the layer can be formed, but optical efficiency deteriorates due to resin degradation at high temperature
Solution Approach 1:
The patent changes the material composition parameter of the optical conversion layer by using inorganic phosphor materials instead of organic resin-based phosphors. This parameter change eliminates the degradation issue at high temperatures while maintaining the layer formation capability, thereby preserving optical efficiency under high-temperature operating conditions.
3Adaptability or versatility
If multiple phosphors are used in separate layers, then light conversion can be achieved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent merges multiple phosphor materials into a single optical conversion layer that can be manufactured as one integrated component. This approach maintains the versatility of using different phosphor types for light conversion while improving manufacturing efficiency by reducing the number of separate manufacturing steps and assembly operations required.
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 solution provides a simple structure with improved durability and thermal stability, maintaining excellent color rendering and light conversion performance even at high temperatures, preventing resin degradation and secondary phase formation.
Implementation Method 1
When light irradiated from a light emitting diode including an LED passes through a phosphor included in the optical conversion layer, a wavelength of the light is adjusted to be emitted to the outside.
Implementation Method 2
the optical conversion layer that does not include a resin, maintaining excellent color rendering and light conversion performance even at high temperatures
Implementation Method 3
a first phosphor and a second phosphor are ball-milled
Implementation Method 4
The heat treatment may include forming the powder of the first phosphor to crystal grains of the first phosphor and forming the powder of the second phosphor to crystal grains of the second phosphor.
Data Source
AI summary
Alighting apparatus can include a light emitting element that can irradiate light, and an optical conversion layer disposed on the light emitting element for converting the irradiated light. The optical conversion layer can include crystal grains of a first phosphor and crystal grains of a second phosphor, and the crystal grains of the first phosphor and the crystal grains of the second phosphor can be in mixed form in the optical conversion layer.