Annular Heat Pipe for LED Junction Temperature Control
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Solution Overview
Problem
Conventional lighting devices face challenges in energy efficiency and heat management, particularly with solid state light emitters like LEDs, which are prone to reduced lifespan and color stability due to temperature variations, and require effective heat transfer solutions to maintain performance.
Innovation Solution
The integration of a heat transfer element, such as a heat pipe with thermal exchange regions, and a heat rim in lighting devices to efficiently manage heat and maintain the junction temperature of LEDs, combined with sensors to adjust current supply for stable color output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If solid state light emitters like LEDs are used to improve energy efficiency, then energy efficiency is improved, but heat management becomes more critical due to temperature sensitivity affecting lifespan and color stability
Solution Approach 1:
A heat transfer element is introduced as an intermediary between the LED light emitter and the housing. This heat transfer element includes a heat pipe with a thermal transfer region in thermal communication with the light emitter, and thermal exchange regions that extend toward the interior surface of the housing. The heat pipe acts as a mediator to conduct heat away from the LED junction through its working fluid cycle (evaporation at hot end, condensation at cold end), preventing direct thermal contact issues while maintaining effective heat removal.
Solution Approach 2:
The patent replaces conventional direct thermal conduction mechanisms (such as simple heat sinks or thermal paste interfaces) with a phase-change-based heat pipe system. The heat pipe uses phase transitions of its working fluid (liquid to vapor at the evaporation region, vapor to liquid at the condensation region) to transfer heat more efficiently, substituting mechanical thermal contact with a thermodynamic cycle that provides superior heat transfer performance and maintains reliable LED operation.
2Temperature
If heat transfer elements with extended thermal exchange regions are used to improve heat management, then heat transfer efficiency is improved, but device complexity increases
Solution Approach 1:
The heat transfer element is designed to perform multiple functions within a single integrated component. It serves as both the primary heat conduction path (through the heat pipe's thermal transfer region) and the heat dissipation interface (through the thermal exchange regions extending to the housing interior surface). This multi-functionality eliminates the need for separate heat sinks, thermal interfaces, and mounting structures, thereby improving heat transfer efficiency without proportionally increasing device complexity.
Solution Approach 2:
The patent merges the heat pipe structure directly with the mounting substrate that holds the LED, creating an integrated heat transfer element. The thermal exchange regions are formed as integral extensions of the heat pipe body, combining the vapor chamber, condensation surface, and heat dissipation interface into a single unified component. This merging reduces assembly steps and structural complexity while maintaining effective heat transfer pathways.
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 solution enhances the energy efficiency and lifespan of LEDs by effectively managing heat and maintaining color stability, ensuring the LEDs operate within optimal temperature ranges and providing accurate light output adjustments.
Implementation Method 1
a heat pipe in thermal communication with the light emitter and the housing
Implementation Method 2
the first thermal exchange region extending in a shape which comprises at least a first portion of a substantially circular substantially annular shape
Data Source
AI summary
A heat pipe configured to transfer heat from a central portion of a lighting device to an edge portion of the lighting device, the heat pipe comprising one region which extends along a portion of a diameter of a substantially circular, substantially annular shape and another region that extends along a diameter of the shape. Also, a lighting device comprising a housing, a reflector, a light emitter and a heat pipe as described above. Also, a self ballasted lamp comprising a solid state light source, an electrical connector, an AC power supply, a reflector configured to receive light from the source and emit reflected light from an aperture, and a thermal management system. Also, a lighting device, comprising a housing, a reflector, a light emitter comprising an array of solid state light emitters, a heat pipe and a sensor.