Light Array Thermal Slope Detection for LED Degradation
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Solution Overview
Problem
Solid-state lighting devices like LEDs experience thermal degradation due to increased heat output as power supplied increases, and if heat is not effectively transferred, their performance degrades, especially when coolant flow becomes restricted.
Innovation Solution
A method that involves monitoring the temperature of light emitting devices and stopping the electrical current flow if the rate of temperature increase exceeds a threshold, using a controller connected to temperature sensors and a heat sink to manage thermal behavior and prevent degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If power supplied to solid-state lighting devices is increased to adjust light intensity, then illumination intensity is improved, but thermal output increases causing device performance degradation
Solution Approach 1:
The patent implements a feedback control system using temperature sensors to monitor the thermal state of light emitting devices and adjust operational parameters accordingly. The controller receives temperature data and modulates power delivery to maintain safe operating temperatures while maximizing light output, resolving the contradiction between illumination intensity and thermal management.
Solution Approach 2:
The system dynamically adjusts the operational state of light emitting devices based on real-time temperature conditions. By transitioning between different power levels or operational modes according to thermal feedback, the system optimizes the balance between light intensity and heat generation, preventing thermal degradation while maintaining illumination performance.
2Temperature
If coolant flow is used to transfer heat away from light emitting devices, then temperature control is improved, but system complexity increases
Solution Approach 1:
The patent introduces a liquid cooling system as an intermediary thermal management mechanism. The coolant circulates through channels in thermal contact with light emitting devices, absorbing heat and transporting it to heat exchangers. This intermediary system efficiently manages heat transfer while keeping the core lighting system relatively simple, resolving the contradiction between effective cooling and system complexity.
3Reliability
If temperature monitoring is implemented to prevent thermal degradation, then device reliability is improved, but response time may be delayed using traditional temperature thresholds
Solution Approach 1:
The patent employs rate-of-change detection to predict thermal runaway conditions before they occur. By monitoring the temporal derivative of temperature rather than relying solely on absolute threshold values, the system can take preliminary protective actions earlier in the thermal degradation process. This predictive approach extends the warning time and allows for more gradual response, improving both reliability and effective response time.
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 provides improved temperature control and reduces the likelihood of light emitting device degradation by shutting down operation before thermal damage occurs, thus maintaining device performance.
Implementation Method 1
a temperature sensing device may be in thermal communication with a heat sink
Implementation Method 2
heat is transferred from the light emitting devices to the heat sink
Data Source
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AI summary
A system and method for operating one or more light emitting device is disclosed. In one example, a system for operating light emitting devices comprises: a DC power supply; a plurality of light emitting devices selectively receiving electrical current from the DC power supply; and a controller including executable instructions stored in non-transitory memory for stopping the electrical current from the DC power supply to the plurality of light emitting devices in response to a rate of temperature increase of the plurality of light emitting devices.