LED Lighting Device with Micro-Lens Light Mixing
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Solution Overview
Problem
Conventional LED modules face challenges in achieving homogeneous circular, symmetric light distribution with controlled emission angles, leading to non-uniform light emission and high production costs due to complex solutions like faceted reflectors and Total Internal Reflection (TIR) lenses, which also suffer from material aging issues when used near heat sources.
Innovation Solution
A lighting device comprising an LED module, a reflector, and a cover with an integrator and micro-lenses, where the inner and outer angular light components are focused and mixed to achieve uniformity, using a heat-resistant reflector and a cover made from cost-effective materials like glass or plastics, with the integrator and micro-lenses designed to guide and mix light components effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If faceted reflectors or TIR lenses are used to mix light and achieve uniform distribution, then light uniformity is improved, but production costs increase and device complexity increases
Solution Approach 1:
The patent replaces expensive, complex faceted reflectors and TIR lenses with a simple, cost-effective cover element that can be mass-produced. The cover integrates optical mixing functions through its geometric design and micro-lens array, eliminating the need for costly precision-machined optical components while maintaining light uniformity.
Solution Approach 2:
The cover is divided into multiple functional zones: an inner zone for collecting direct light from the LED, an outer zone for receiving reflected light, and a micro-lens array zone for optical mixing. This segmentation allows each zone to perform its specific function efficiently, achieving overall light uniformity through coordinated action of simplified sub-components.
2Illumination intensity
If TIR lenses made of PC or PMMA are used to control light, then light control is improved, but reliability deteriorates due to material aging near heat sources
Solution Approach 1:
The patent changes the material parameter from thermoplastics (PC/PMMA) to glass or heat-resistant plastics, and adjusts the operational temperature parameter by positioning the heat-resistant cover away from the LED heat source. This allows the use of lower-cost materials while maintaining reliability through thermal parameter management.
Solution Approach 2:
The patent introduces a reflector as an intermediary element between the LED and the cover. The reflector redirects light paths, allowing the cover to be positioned at a distance from the heat source while still achieving effective light control. This intermediary enables thermal separation while maintaining optical functionality.
3Ease of manufacture
If a simple cover is used without complex optics, then production costs are reduced, but light uniformity deteriorates
Solution Approach 1:
The cover serves multiple functions simultaneously: it protects the LED, distributes light uniformly across the emission area, mixes light from different zones, and can be positioned to manage thermal effects. By integrating these multiple functions into a single simple component, the patent achieves light uniformity without requiring separate complex optical elements.
Solution Approach 2:
The patent replaces complex mechanical optical systems (faceted reflectors, TIR lenses) with a simpler geometric-optical system based on the cover's shape and micro-lens array. The optical mixing is achieved through the cover's structural design rather than through complex mechanical optical components, reducing manufacturing complexity while maintaining 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
The solution provides improved color homogeneity and longer optics lifetime with reduced production costs, ensuring reliability against blue light and high temperatures, and achieving light uniformity with minimal variation in intensity across the emission range.
Implementation Method 1
at least part of the cover comprises on its surface micro-lenses for further mixing the light components
Implementation Method 2
the light component in the outer angular region is reflected by the reflector on an outer zone of the cover
Implementation Method 3
the inner zone of the cover comprises for this purpose a lens for focusing the light component in the inner angular zone
Data Source
Figure 1~2
Figure 3~4
Figure 5a~5b
AI summary
A lighting device includes at least one LED module (10) emitting a first light component (12) in an inner angular range (108) and a second light component (14) in an outer angular range as well as a cover (30) and a reflector (20) coupled with the LED module (10). The cover (30) includes an inner zone (34) and an outer zone (32), whereby the first light component (12) is collected in the inner zone (34) of the cover (30). The reflector (20) is configured to reflect the second light component (14) towards the outer zone (32) of the cover (30), so that the second light component (14) is reflected in the direction of said first light component (12). At least part of the cover (30) is provided with micro-lenses (38, 42) for mixing the first (12) light component and the second reflected (14) light component.