Self-Cooling LED Light Source Using Translucent Thermal Elements
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high cost of solid state light sources is a barrier to their widespread adoption due to the expensive LED package and heat sink components, which account for 70% of the cost, and the need for high-cost processing of thermally conductive materials to achieve efficient heat dissipation and light transmission.
Innovation Solution
The use of lower-cost, mostly reflective thermally conductive translucent elements that form a light recycling cavity, allowing for efficient heat dissipation and light extraction without the need for an appended heat sink, by redirecting and recycling light within a closed cavity, thereby reducing material costs and enhancing cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high transparency thermally conductive materials are used for effective heat dissipation, then cooling efficiency is improved, but material processing cost increases significantly
Solution Approach 1:
The patent changes the optical parameter of the thermally conductive material from high transparency to high reflectivity. By using mostly reflective materials (reflectivity >80%) instead of highly transparent materials, the invention achieves effective heat dissipation through radiative cooling while avoiding expensive hot isostatic pressing processing, thereby reducing material costs significantly
Solution Approach 2:
The patent converts the typically harmful heat radiation into a beneficial cooling mechanism. By designing the light transmissive thermally conductive material with high reflectivity in the visible range and high emissivity in the infrared range, the material reflects visible light (maintaining light recycling) while efficiently radiating heat in the infrared spectrum, achieving passive radiative cooling
2Temperature
If large surface area heat sinks are used for natural convection cooling, then cooling efficiency is improved, but device weight and complexity increase
Solution Approach 1:
The patent makes the light transmissive thermally conductive material itself perform the heat dissipation function. The material serves dual purposes: guiding light from LEDs and dissipating heat through its own surface via natural convection and radiation. This eliminates the need for separate appended heat sinks, reducing device weight and simplifying structure
Solution Approach 2:
The light transmissive thermally conductive material is designed to perform multiple functions simultaneously: (1) guide and transmit light from LEDs, (2) conduct heat away from LED junctions, and (3) dissipate heat to ambient through its surface. This multi-functionality eliminates the need for separate heat sink components
3Temperature
If separate LED packages and heat sinks are used, then heat management is effective, but manufacturing cost increases due to assembly complexity
Solution Approach 1:
The patent merges the LED package, heat sink, and light guide into a single integrated light transmissive thermally conductive component. The LED is mounted directly onto this integrated component, eliminating the need for separate heat sink assembly and reducing manufacturing complexity and costs
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 results in a cost-effective, self-cooling solid state light source with improved light extraction efficiency and reduced thermal resistance, enabling omnidirectional and uniform light emission without the need for additional heat sinking elements.
Implementation Method 1
heat is transmitted from the light source in basically the same direction as emitted light... Heat generated in the light source is transmitted principally in the same direction as the direction of light emission
Implementation Method 2
The light transmitting thermally conductive elements have surface areas sufficiently larger than the LEDs (or LEDs mounted to ceramic surface mount substrates) to dissipate the heat generated by the LEDs... to provide convective and radiative cooling
Implementation Method 3
to provide convective and radiative cooling... Very little radiative cooling takes place... to enable more radiative cooling of the light source
Implementation Method 4
at least one light transmitting thermally conductive translucent element to which the LED is mounted, the element having a heat emitting surface through which most of the heat from the LED is dissipated... light is emitted from the LED die principally in a direction through the at least one luminescent element
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3A~3C
AI summary
A solid state light source with LEDs in thermal contact to thermally conductive translucent elements where light emitted from the LEDs is directed to emerge from the heat dissipating surfaces of the elements. The thermally conductive translucent elements are arranged or combined with a reflector to form a light recycling cavity. The outside surfaces of the thermally conductive translucent elements forming the cavity become luminescent as the light emitted by the LEDs on the inside of the cavity is continually reflected and recycled until a very high percentage of the light emitted by the LEDs is eventually transmitted through and emitted uniformly and omnidirectionally. Simultaneously, the heat from the LEDs conducts through and to the luminescent outside surfaces of the elements of the cavity, which radiatively and convectively cool the light source thereby eliminating the need for bulky appended heat sinks.