UV-C LED Module Solid Coupling Light Extraction
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Solution Overview
Problem
UV-C LED water purification devices face inefficiencies in light extraction due to air gaps between LED dies and output windows, leading to reduced performance and shorter lifetimes, which increases bulk, weight, and operating costs.
Innovation Solution
The UV-C LED modules are designed with flip-chip dies solidly coupled to translucent window elements, eliminating air gaps and using reflective sealing layers to conserve light and enhance heat dissipation, thereby improving light extraction efficiency and reducing heat-related performance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If UV-C LED packages use traditional glass window attached to ceramic cavity with air gap, then light extraction efficiency is low, but device structure is simple
Solution Approach 1:
The patent extracts and eliminates the air gap between the LED die and glass window, which was causing light reflection losses. By removing this intermediate space, the design achieves direct solid-to-solid optical coupling, significantly improving light extraction efficiency while simplifying the overall structure.
Solution Approach 2:
The patent merges the LED die mounting structure with the glass window by directly attaching the die to the window surface. This consolidation eliminates the separate air cavity component and reduces the number of interfaces, thereby improving optical efficiency without substantially increasing structural complexity.
2Illumination intensity
If greater density of LED packages is incorporated to achieve required light intensity, then light intensity is sufficient, but bulk and weight increase
Solution Approach 1:
The patent changes the optical coupling parameter by eliminating the air gap, which increases the light extraction efficiency of each individual LED package. This allows achieving the same total light intensity with fewer packages, thereby reducing the overall weight of the device.
3Illumination intensity
If larger drive current is provided to achieve required light intensity, then light intensity is sufficient, but running costs increase
Solution Approach 1:
The patent converts the previously harmful effect of the air gap (which caused light reflection and energy loss) into a benefit by eliminating it. This improves the electrical-to-optical conversion efficiency of each LED package, reducing the total energy consumption required to achieve the desired light intensity.
4Illumination intensity
If UV-C LED junction is heated to provide higher light output, then light intensity increases, but lifetime is reduced
Solution Approach 1:
The patent extracts and removes the air gap that was acting as a thermal insulator between the LED die and heat sink. This improves thermal conduction, allowing heat to be efficiently conducted away from the junction, thereby maintaining reliability while achieving higher light output.
5Loss of energy
If reflective sealing layer is added to conserve light, then light extraction efficiency improves, but device complexity increases
Solution Approach 1:
The patent implements a sealing layer that simultaneously performs multiple functions: it provides environmental sealing for the LED die, creates mechanical bonding between components, and acts as a reflective surface to redirect light. This multi-functionality improves light extraction efficiency without substantially increasing structural complexity.
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 achieves higher light extraction efficiency, allowing for increased light intensity without increasing device bulk or weight, and extends the operational lifespan of UV-C LED modules while reducing energy consumption and production costs.
Implementation Method 1
UV-C light at sufficiently short wavelengths is mutagenic to bacteria, viruses and other micro-organisms. At a wavelength of around 265 nm, UV breaks molecular bonds of DNA in the cells of micro-organisms
Implementation Method 2
At a wavelength of around 265 nm, UV breaks molecular bonds of DNA in the cells of micro-organisms, producing thymine dimers in the DNA, thereby destroying the DNA structure necessary to reproduce the cell
Implementation Method 3
the associated UV-C-translucent window element is for transferring heat from the UV-C LED die
Implementation Method 4
the sealing layer being UV-C light reflective, and wherein the sealing layer is covering the bottom surface of the UV-C LED die
Data Source
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AI summary
Methods and apparatus are provided for ultraviolet (UV) water purification, comprising UV-C LED modules having improved light extraction efficiency. UV-C LED dies (12) are solidly coupled to associated translucent output windows (14), such that light is transmitted directly from light-emitting surface(s) of the dies (12) to output window(s) (14) of the LED package - without propagation across interstitial air gaps. Gas-to-solid (and solid-to-gas) light transition boundaries are thus eliminated, significantly reducing the amount of light lost through inter-medium boundary reflection, and thereby increasing efficiency of light extraction.