LED Lighting Fixture Thermal Management and Optical Design
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Solution Overview
Problem
High bay lighting fixtures face challenges in efficiently dissipating heat generated by high intensity LEDs, leading to potential failure and performance degradation, and require cost-effective solutions to achieve desired emission profiles without expensive optics.
Innovation Solution
The solution involves mounting LEDs directly on a heat sink without an intervening circuit board, using a template-style circuit board with cut-outs for improved thermal dissipation and a reflector with a specific arc cross-section to achieve a high spacing criterion, thereby reducing glare and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high intensity LEDs are used to provide sufficient illumination, then lighting intensity is improved, but heat generation increases leading to potential failure and performance degradation
Solution Approach 1:
The patent extracts the circuit board from the thermal path between the LED and heat sink. By mounting the LED directly on the heat sink without an intervening circuit board, the thermal connection is improved while the circuit board is relocated to a non-interfering position, thereby reducing thermal resistance and improving heat dissipation effectiveness.
Solution Approach 2:
The patent introduces a template-style circuit board with cut-outs as an intermediary structure that allows thermal contact between the LED and heat sink while still providing electrical connections. The cut-outs in the circuit board create thermal pathways that enable heat to flow from the LED to the heat sink without being blocked by the circuit board material.
2Ease of manufacture
If a traditional circuit board is used to mount LEDs, then electrical connections are simplified, but thermal dissipation is reduced due to the intervening board
Solution Approach 1:
The circuit board is segmented with cut-outs that remove material from the thermal path. This segmentation allows heat to flow through the board more effectively by creating thermal pathways, while the remaining board structure continues to provide electrical connections and mechanical support.
Solution Approach 2:
The circuit board has different properties in different regions: areas with cut-outs provide thermal pathways, while areas with traces and pads provide electrical connections. This local differentiation allows the board to simultaneously support both electrical and thermal functions in appropriate regions.
3Illumination intensity
If expensive optics are used to achieve desired emission profiles, then lighting control is improved, but cost increases
Solution Approach 1:
The patent replaces expensive optical components with a simpler, more cost-effective reflector design. The reflector uses basic geometric shapes (parabolic and conic sections) that can be manufactured at lower cost while still achieving the desired emission profiles and spacing criteria.
Solution Approach 2:
The patent changes the geometric parameters of the reflector (parabolic depth, conic section ratios) to optimize emission profiles. By adjusting these geometric parameters, the system achieves controlled light distribution without requiring expensive optical lenses or diffusers.
4Illumination intensity
If a reflector with specific arc cross-section is used, then spacing criterion is improved, but manufacturing complexity increases
Solution Approach 1:
The reflector uses curved surfaces defined by parabolic and conic sections to achieve the desired emission patterns. These curved geometries naturally direct light rays to create uniform spacing criteria while being manufacturable using standard forming processes for rotational symmetric shapes.
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 approach enhances thermal dissipation, reduces the need for expensive thermal management components, and achieves a high spacing criterion with a flat lens, improving the reliability and cost-effectiveness of high bay lighting fixtures.
Implementation Method 1
mounting LEDs directly on a heat sink without an intervening circuit board
Implementation Method 2
heat sink
Implementation Method 3
a reflector with a specific arc cross-section to achieve a high spacing criterion
Data Source
AI summary
The present invention relates to different embodiments of lighting fixtures, such as high bay lighting fixtures, comprising one or more improved features. Some of these features include the direct mounting of emitters on a heat sink and/or the use of a template-like board for providing an electrical connection between emitters. These features can improve heat dissipation from the emitters and simplify fabrication. In other embodiments, expensive lens optics of prior art SSL fixtures can be replaced with a flat lens and reflector in order to produce a fixture having a satisfactory spacing criterion.