LED Thermal Management via Dynamic Model Optimization
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Solution Overview
Problem
The widespread use of LEDs in general illumination is hindered by their decreased luminous efficacy due to increasing junction temperature, which results in reduced light output, especially in high-temperature applications like automobile headlights and compact lamps, where the heat sink size is limited.
Innovation Solution
A method and numerical tool that uses a computer-implemented dynamic model to calculate and optimize the luminous performance of LED systems by managing junction temperature, allowing for modification of the LED system to prevent peak junction temperatures from exceeding maximum rated values, thereby maintaining desired luminous performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LED power output is increased to achieve higher illumination, then luminous flux increases, but junction temperature rises causing luminous efficacy to decrease
Solution Approach 1:
The patent applies dynamics by making the LED system adjustable and controllable through a computer-implemented dynamic model. The system allows real-time monitoring and adjustment of operating parameters (current, voltage, power) to optimize luminous flux output while maintaining junction temperature within acceptable ranges, thereby preventing efficacy degradation.
Solution Approach 2:
The patent utilizes parameter changes by dynamically adjusting electrical parameters (current, voltage, power) based on the dynamic thermal model predictions. The system modifies these parameters to achieve optimal balance between luminous flux output and junction temperature control, maximizing luminous efficacy at different operating conditions.
2Loss of energy
If heatsink size is increased to reduce junction temperature, then luminous efficacy is maintained, but device size and complexity increase
Solution Approach 1:
The patent applies preliminary action by using the computer-implemented dynamic model to predict thermal behavior and optimize operating parameters before actual operation. The system calculates optimal current, voltage, and power settings in advance based on desired luminous flux and acceptable temperature ranges, eliminating the need for oversized heatsinks.
Solution Approach 2:
The patent replaces the mechanical thermal management approach (larger heatsinks) with a computational approach. The computer-implemented dynamic model substitutes physical thermal mass with algorithmic prediction and control, allowing optimal thermal management through software-based parameter optimization rather than hardware expansion.
3Productivity
If LED operates at high power for extended periods, then illumination output is maintained, but thermal accumulation reduces lifespan
Solution Approach 1:
The patent applies feedback by using the dynamic thermal model to continuously monitor and predict junction temperature based on operating conditions. The system provides feedback on thermal state and adjusts operating parameters accordingly, preventing thermal accumulation that would reduce lifespan while maintaining required illumination output.
Solution Approach 2:
The patent applies partial action by operating LEDs at optimized power levels rather than maximum continuous power. The dynamic model determines appropriate operating points that provide sufficient illumination output while keeping thermal stress within acceptable limits, extending LED lifespan through controlled partial operation.
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 effectively maximizes luminous flux and efficacy by optimizing the thermal design of LED systems, ensuring that they operate within safe temperature limits, thus extending the lifespan and enhancing the performance of LEDs in various applications.
Implementation Method 1
a heatsink with a thermal resistance such that the maximum luminous flux is emitted at a power below a rated power of the LEDs
Implementation Method 2
The light-emitting chip is covered by a silicone encapsulant and a plastic lens
Data Source
AI summary
Methods and numerical tools for designing and optimizing LED systems are provided to achieve a desired luminous performance and to increase reliability and operating lifetime. In addition, methods for designing LED illumination systems are also disclosed to determine an optimum operating power for a desired output luminous flux, given the condition of the rated power of the LED and the heatsink. By the invention, LED illumination systems can be designed with a suitable choice of LED and/or heatsink.