UV LED Reflector Geometry for Compact Radiation Control
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Solution Overview
Problem
Existing UV-LED reflector cup designs suffer from optical inefficiency due to radiation not being adequately directed, leading to a trade-off between optical efficiency, control, cost, and size, with a desire for cost-effective, small-sized emitters that maximize radiation directionality and distribution control.
Innovation Solution
A UV radiation emitting assembly with a reflector having a three-dimensional shape defined by a smooth, continuous curve, capturing radiation from UV-LEDs over a wide emission angle range, using specular reflection materials, and optionally incorporating a thermally conductive design for heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a large reflector cup is used to increase optical efficiency and control over UV rays, then optical efficiency and radiation control are improved, but cost and device size increase
Solution Approach 1:
The reflector cup employs a curved reflective surface with a specific geometric profile (parabolic, elliptical, or freeform) that optimizes light reflection and directionality. The curvature is designed to capture UV rays over a wide emission angle range and redirect them efficiently, achieving high optical efficiency without requiring an excessively large reflector size.
Solution Approach 2:
The patent optimizes specific parameters of the reflector cup including the emission angle range (φ ≥ 50°), the angular range spanned by the reflector (120°-300°), and the geometric profile of the reflective surface. These parameter optimizations enable the reflector to effectively control UV radiation while maintaining a compact size that balances performance with cost and application requirements.
2Volume of stationary object
If the reflector cup does not extend sufficiently far in the direction of the UV-LED's principal optical axis, then device size is reduced, but optical efficiency deteriorates due to radiation not impinging on the reflective surface
Solution Approach 1:
The curved reflective surface is specifically designed with an optimized profile that maximizes the capture of UV rays within a compact axial extension. The curvature ensures that rays emitted over a wide angle range (φ ≥ 50°) are effectively reflected and directed, achieving high optical efficiency without requiring the reflector to extend excessively far along the optical axis.
Solution Approach 2:
The reflector cup spans a wide angular range (120°-300°) around the optical axis, utilizing the angular dimension to capture and control UV radiation. This angular coverage compensates for the limited axial extension, allowing the compact reflector to intercept and redirect a significant portion of emitted UV rays that would otherwise be lost.
3Ease of manufacture
If a symmetric reflector cup design is used, then manufacturing is simplified, but flexibility to control radiation directionality and distribution is reduced
Solution Approach 1:
The patent employs asymmetric freeform reflective surface profiles that are specifically designed to control and shape UV radiation patterns according to application requirements. These asymmetric geometries provide superior flexibility in directing radiation to specific zones or angles, enabling customized radiation distribution patterns that symmetric designs cannot achieve.
Solution Approach 2:
The reflective surface features locally optimized zones with varying curvature and orientation to control radiation in different directions. Different portions of the reflector are designed with specific geometric properties to direct UV rays to desired locations, providing localized control over radiation distribution while maintaining overall system performance.
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
Enhances optical efficiency by directing a significant portion of UV radiation into a controlled pattern, balancing size and cost while allowing flexible radiation control, suitable for disinfection applications.
Implementation Method 1
using specular reflection materials
Implementation Method 2
optionally incorporating a thermally conductive design for heat dissipation
Data Source
AI summary
A light emitting assembly comprises an ultraviolet (UV) light emitting diode (LED) coupled to a UV reflector. The reflector has a three-dimensional shape spanning an angular range between 0° and 180° about a principal reflector axis of the reflector. The reflector is smooth and continuous across its entire surface. The UV-LED is directed towards a reflective surface of the reflector instead of towards the fluid to be treated. A central ray of the UV-LED impinges directly on the reflective surface of the reflector.