LED Junction Temperature Compensation for Stable Optical Output
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Solution Overview
Problem
Diagnostic assay systems face challenges due to temperature fluctuations affecting optical components, leading to performance degradation and reduced lifespan, especially in inhospitable environments with limited access to replacements.
Innovation Solution
A system and method for monitoring and compensating LED performance by measuring voltage across LEDs, correlating it to junction temperature, and adjusting operation to stabilize photonic output, thereby reducing noise and extending LED life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature compensation is implemented using voltage measurement, then LED performance stability is improved, but device complexity increases due to additional monitoring circuitry
Solution Approach 1:
The LED itself provides the temperature information through its forward voltage measurement. The LED's electrical characteristics change with temperature, and by measuring the voltage across the LED at a known current, the system can determine junction temperature without requiring external temperature sensors. This self-service approach reduces device complexity while maintaining reliability.
Solution Approach 2:
The forward voltage of the LED serves as an intermediary parameter that indirectly indicates junction temperature. Instead of directly measuring temperature with separate sensors, the system uses voltage measurement as a mediator to infer thermal conditions, enabling compensation while minimizing additional hardware.
2Measurement precision
If voltage measurement is used to correlate junction temperature, then temperature sensing capability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The system measures the forward voltage of the LED and uses this information to feedback control the drive current or duty cycle, maintaining consistent optical output despite temperature variations. This closed-loop approach compensates for manufacturing variations and ensures accurate temperature correlation across different LED units.
Solution Approach 2:
The system exploits the change in electrical parameters (forward voltage) of the LED with temperature. By monitoring how the voltage parameter changes with temperature, the system can accurately sense junction temperature without requiring high-precision absolute voltage measurements, as only relative changes need to be detected.
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 system improves LED performance by stabilizing photonic output, reducing noise, and extending LED lifespan, even in harsh environments, ensuring reliable operation of diagnostic assays.
Implementation Method 1
a light-emitting diode (LED) configured to provide an optical output for excitation of a biological sample
Implementation Method 2
a control unit having a processor and a voltage sensor, the control unit configured to operate the LED to monitor the performance of the assay
Data Source
AI summary
Systems and methods for monitoring, characterizing and controlling operation of LEDs are provided herein. Methods includes measuring a voltage across the LED, and correlating the voltage to a junction temperature of the LED. This correlation can be used to improve operation of the LED by increasing the signal to noise ratio of the LED signal, characterize the LED by comparing to an I-V curve, control LED operation to compensate for LED degradation and avoid crosstalk, and/or to generally improve performance and life expectancy of the LED. Improved performance of the LED can include stabilizing the photon output during performance of an assay to provide a desired dye reporter signal required for the assay and/or reducing an intra-shot during of the LED output during the assay. System and device with control units configured to perform these methods are also described herein.