LED Lamp Envelope Sheet Metal Heat Spreader Thermal Management
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Solution Overview
Problem
Existing solid state lighting devices, such as LED lamps, are limited by their thermal properties and available space for driver electronics, necessitating a solution that balances thermal efficiency with cost and optical performance.
Innovation Solution
A lighting device featuring a sheet metal heat spreader element separated from the inner surface of the envelope by a predetermined distance, allowing for efficient heat dissipation and increased volume for driver electronics, while preventing optical coupling and utilizing thin, less conductive materials for the sheet metal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the sheet metal element is placed in direct contact with the inner surface of the envelope, then thermal conduction is maximized, but optical coupling occurs that interferes with light distribution
Solution Approach 1:
The patent introduces an intermediary substance (adhesive layer, thermal paste, or air gap) between the sheet metal element and the envelope's inner surface. This intermediary allows thermal conduction to occur while preventing direct optical coupling that would interfere with light distribution. The intermediary layer acts as a thermal bridge while remaining optically transparent or reflective.
Solution Approach 2:
The patent transitions from a two-dimensional contact problem to a three-dimensional solution by creating a controlled gap or layer with specific thickness. This dimensional approach allows simultaneous optimization of thermal conduction (through the intermediary layer) and optical performance (by preventing direct metal-to-glass contact that would cause shadows or reflections).
2Volume of stationary object
If the envelope's internal volume is used for positioning driver electronics, then the lighting device becomes more compact, but thermal management becomes more difficult
Solution Approach 1:
The patent merges the thermal management function with the structural envelope by integrating a sheet metal element that serves dual purposes: as a structural component of the envelope and as a heat spreader. This allows driver electronics to be positioned within the envelope's internal volume while heat from these components is efficiently conducted through the sheet metal element to the envelope's outer surface.
Solution Approach 2:
The sheet metal element performs multiple functions simultaneously: it provides structural support to the envelope, acts as a heat spreader for thermal management, and serves as a mounting surface for driver electronics. This multi-functionality allows compact integration of components without compromising thermal performance.
3Temperature
If expensive materials and complex structures are used to improve thermal properties, then thermal performance increases, but manufacturing cost increases
Solution Approach 1:
The patent employs inexpensive sheet metal materials (such as aluminum or steel) instead of expensive specialized thermal management materials. The simple sheet metal element can be easily manufactured and replaced if needed, providing cost-effective thermal management without requiring complex or expensive components.
Solution Approach 2:
The patent optimizes thermal performance by adjusting parameters of the sheet metal element (such as thickness, surface area, and thermal conductivity) rather than changing the fundamental material type. This allows achieving desired thermal properties through dimensional optimization of common materials, avoiding the need for expensive specialized materials.
4Ease of manufacture
If the sheet metal element is made thin to reduce cost, then manufacturing cost decreases, but thermal conduction efficiency reduces
Solution Approach 1:
The patent uses an intermediary substance between the thin sheet metal element and the envelope to enhance thermal conduction. This intermediary (such as thermal paste or an adhesive layer with high thermal conductivity) compensates for the reduced thermal mass of the thin sheet metal, allowing cost-effective thin materials to achieve adequate thermal performance.
Solution Approach 2:
The patent compensates for reduced thickness by optimizing other parameters such as the surface area of the sheet metal element, its geometric configuration, and the thermal conductivity of the intermediary layer. This allows maintaining thermal efficiency while using thinner, less expensive materials.
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 a low-cost, high-efficiency lighting device with improved thermal properties and omni-directional light distribution, enabling larger driver electronics volume without shadowing or interference with light output.
Implementation Method 1
a sheet metal element, i.e. a heat spreader element arranged at the inner surface
Implementation Method 2
an envelope (15) comprising an outer surface (15a) arranged for distributing light from the multiple of light sources
Data Source
AI summary
There is provided a lighting device (10) which is suitable for a retrofit LED lamp, and which comprises an envelope (15) surrounding an inner volume (16), of which envelope an outer surface (12a) is arranged for distributing light from a multiple of light sources (19) of the lighting device. An inner surface (12b) of the envelope is utilized for providing a low thermal resistance of the lighting device on a system level by being at least partly covered by a sheet metal element (13). Driver electronics (17) of the light sources are arranged within the inner volume.