LED Lighting Device with Non-Rigid Thermal Medium
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Solution Overview
Problem
High power LEDs used in lighting applications face challenges with heat dissipation and mechanical stress due to rigid mounting, which can lead to damage from thermal expansion and vibration, and existing solutions suffer from degradation and manufacturing difficulties.
Innovation Solution
A lighting device with an LED-unit rigidly coupled to a collimator, using a non-rigid heat transferring medium within a sealed cavity, and a TIR collimator for enhanced heat dissipation and mechanical support, avoiding substantial forces on the LED-unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the LED is rigidly mounted between a heat sink and a reflector to dissipate heat, then heat dissipation is improved, but mechanical forces are applied to the LED which may damage the device
Solution Approach 1:
The mounting structure is segmented into separate functional zones: the LED is rigidly coupled only to the collimator for optical support, while heat dissipation is handled separately through a heat sink with thermal vias and conductive paths in the PCB, eliminating mechanical stress from the LED while maintaining thermal management
Solution Approach 2:
The collimator serves as an intermediary element that provides rigid mechanical support to the LED without being part of the heat sink assembly. This intermediary structure allows the LED to be firmly mounted for optical alignment while isolating it from thermal expansion forces and mechanical stresses of the heat sink
2Illumination intensity
If an index-matching fluid is used to fill the space between the LED and TIR reflector to improve optical efficacy, then optical performance is improved, but the device has limited lifetime due to thermal expansion coefficient mismatches and fluid degradation
Solution Approach 1:
The index-matching fluid is completely removed from the optical system. Instead, the patent achieves optical coupling through direct contact between the LED and the TIR collimator, eliminating the fluid medium that causes thermal expansion mismatches and degradation over time
Solution Approach 2:
The patent uses a TIR (total internal reflection) collimator made from transparent plastic material that combines optical functionality with structural support. This composite approach eliminates the need for separate index-matching fluid while maintaining high optical efficacy through the collimator's inherent total internal reflection properties
3Stability of the object's composition
If the LED is rigidly coupled to multiple components (heat sink and reflector) to provide mechanical support, then structural stability is improved, but substantial forces are applied to the LED which may damage the device
Solution Approach 1:
The structural support function is segmented and assigned solely to the collimator, which is rigidly coupled to the LED. The heat sink and PCB provide separate thermal management pathways without mechanical coupling to the LED, dividing structural, thermal, and optical functions into distinct components
Solution Approach 2:
The collimator acts as an intermediary mounting structure that provides all necessary mechanical support and optical alignment for the LED. This single intermediary component eliminates the need for dual rigid mounting to heat sink and reflector, reducing cumulative mechanical stresses while maintaining structural stability
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 effective heat dissipation and mechanical support, reducing the risk of damage from thermal expansion and vibration while simplifying manufacturing by using a non-rigid heat transferring medium and a TIR collimator, ensuring high optical efficacy and extended device lifetime.
Implementation Method 1
the housing comprises a cavity, in which a non-rigid heat transferring medium is contained... so as to dissipate heat, generated in the LED-unit
Implementation Method 2
The type of the heat-transporting mechanism can be either a convection-type or a heat-pipe mechanism
Implementation Method 3
In the present context, the term 'collimator' is understood to include also reflectors of any suitable type... a TIR (total internal reflection) reflector 10b is arranged on top
Implementation Method 4
In a heat-pipe mechanism, fluid heat-pipe medium is arranged in a sealed cavity in close contact to a heat source. Due to the heat produced at the heat source, parts of the heat-pipe-fluid are evaporated. The vapor then condenses at a colder heat-sink of the cavity
Implementation Method 5
parts of the heat-pipe-fluid are evaporated
Implementation Method 6
The vapor then condenses at a colder heat-sink of the cavity
Data Source
Figure 1~2
Figure 3~4
Figure 5~6b
AI summary
A lighting device (1) comprising an LED-unit (5) , a collimator (2) and a housing (3) , the LED-unit (5) is rigidly coupled to the collimator (2) only, so that no substantial forces can be applied to the LED-unit (5) . A non-rigid heat transferring medium (10) is provided in a cavity (12) in the housing (3) , to dissipate heat, generated by the LED-unit (5) . The LED-unit (5) is therefore at least partly contained in the heat transferring medium (10) .