Ceramic Conversion Element Structured Surface Light Extraction
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Solution Overview
Problem
Current light-emitting devices, such as LEDs and LASERs, face inefficiencies due to the surface structure of conversion elements, leading to inner total reflection and reduced coupling out of primary and secondary radiation.
Innovation Solution
A ceramic conversion element with a structured top surface and a surrounding frame, formed from a single piece of ceramic material, is designed to convert primary radiation into secondary radiation of a different wavelength range, minimizing inner total reflection and optimizing radiation coupling through a planar bottom surface and controlled emission direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a planar top surface is used for the conversion element, then the manufacturing is simple, but the coupling out of radiation is reduced due to inner total reflection
Solution Approach 1:
The patent applies curvature by structuring the top surface with microlens arrays or dome-shaped features instead of a flat plane. These curved structures refract and focus light to escape the high-refractive-index ceramic material, reducing total internal reflection and improving light extraction efficiency while maintaining manufacturability through standard semiconductor packaging processes.
2Stability of the object's composition
If the conversion element is made completely from ceramic materials as a monolithic structure, then the thermal management and mechanical stability are improved, but the surface structure control for optimizing radiation coupling becomes more difficult
Solution Approach 1:
The patent segments the monolithic ceramic conversion element into distinct functional regions: a bulk ceramic substrate for thermal management and mechanical stability, and a structured top surface with microlens arrays or patterned features for optimized radiation coupling. This segmentation allows each region to be optimized independently while maintaining overall structural integrity.
3Productivity
If a structured top surface with multiple structure elements is implemented, then the radiation coupling out is increased, but the device complexity increases
Solution Approach 1:
The patent optimizes radiation coupling by systematically varying parameters of the surface structure elements, including lens diameter (5-50 micrometers), depth (2-20 micrometers), spacing patterns, and refractive index profiles. These parameter optimizations achieve high light extraction efficiency while maintaining manufacturability through established semiconductor packaging techniques.
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 ceramic conversion element enhances the efficiency of light-emitting devices by increasing the coupling out of primary and secondary radiation, potentially increasing brightness by up to 3% and improving angular uniformity.
Implementation Method 1
the ceramic conversion element comprises a phosphor, which converts primary radiation of a first wavelength range into secondary radiation of a second wavelength range
Implementation Method 2
Due to the changed angle of impact less inner total reflection of primary radiation and/or secondary radiation occurs at the radiation exit surface
Data Source
AI summary
A ceramic conversion element, a light-emitting device and a method for producing a ceramic conversion element are disclosed. In an embodiment a ceramic conversion element includes a central region with a structured top surface including a plurality of structure elements and a frame surrounding the central region, the frame having a planar top surface, wherein the central region and the frame are formed as one piece, and wherein the ceramic conversion element is configured to convert primary radiation into secondary radiation of a different wavelength range.