Lighting Device With UV-Resistant Optical Light Distribution
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Solution Overview
Problem
Existing UV LED lighting devices with light guide panels suffer from limited lifetime due to local material degradation caused by UV exposure, particularly in applications requiring UV-C, UV-B, and UV-A/Violet light.
Innovation Solution
Incorporating an optical element made of a more UV-resistant material than the light guide panel, which distributes UV/violet light over a larger area before coupling it into the panel, and positioning UV/violet light sources further from the light incoupling part to reduce local intensity, thereby preventing material degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UV light sources are directly coupled into the light guide panel, then the sterilization function is achieved, but local material degradation occurs reducing device lifetime
Solution Approach 1:
A transparent optical element is introduced as an intermediary component between the UV light source and the light guide panel. This optical element distributes the UV light over a larger area before it enters the light guide panel, preventing concentrated UV exposure that causes local material degradation. The optical element is made of UV-resistant material to ensure it can withstand direct UV exposure without degrading.
Solution Approach 2:
The patent applies different material properties to different parts of the system. The optical element is made of UV-resistant material (such as UV-cured acrylic or UV-resistant polymer) while the light guide panel uses standard light-guiding material. This local differentiation allows the UV-resistant optical element to protect the light guide panel from UV-induced degradation.
2Productivity
If UV light sources are positioned close to the light incoupling part, then the light coupling efficiency is improved, but material degradation accelerates
Solution Approach 1:
The transparent optical element serves as a mediator that allows the UV light source to be positioned close to the light incoupling part for efficient coupling, while simultaneously protecting the light guide panel from direct UV exposure. The optical element redistributes the UV light over a larger area, decoupling the proximity benefit from the degradation harm.
3Object-affected harmful factors
If the light guide panel material is made more UV resistant, then material degradation is reduced, but light guiding properties may be compromised
Solution Approach 1:
The patent assigns different functional requirements to different components: the optical element requires high UV resistance to withstand direct UV exposure, while the light guide panel requires optimal light guiding properties. By separating these functions into different components with specialized materials, both UV resistance and light guiding stability are optimized without compromise.
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 extends the lifetime of the lighting device by minimizing local material degradation, ensuring the light guide panel remains functional for a longer period without significant deterioration.
Implementation Method 1
at least part of the visible light that is coupled into the light guide panel is guided (via total internal reflection) by the light guide panel
Implementation Method 2
an optical element made of a first material which is different and more UV resistant than a second material that the light guide panel is made of, wherein the optical element is adapted to distribute light emitted by the at least one second light source over an area which is larger than a total light output surface area of the at least one second light source
Data Source
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AI summary
The present invention relates to a lighting device (10), comprising: a plurality of first light sources (24) adapted to emit visible light (24'); a light guide panel (12), wherein visible light emitted by the plurality of first light sources in operation is coupled into the light guide panel via a light incoupling part (16a); at least one second light source (28) adapted to emit at least one of UV light (28') and violet light to be coupled into the light guide panel via a light incoupling part (16a; 16b); and an optical element (30; 30'; 30''; 42) made of a first material which is different and more UV resistant than a second material that the light guide panel is made of, wherein the optical element is adapted to distribute light emitted by the at least one second light source over an area (34; 46) which is larger than a total light output surface area (35) of the at least one second light source before the light is coupled into the light guide plate.