LED Luminaire Temperature Feedback Control
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Solution Overview
Problem
RGBW LED lamps face accuracy issues in delivering consistent color due to temperature variations, as LED output is temperature-dependent, leading to color inaccuracies when ambient temperatures deviate from the calibration temperature.
Innovation Solution
Incorporating a thermistor sensing system that monitors temperature changes and adjusts the electrical signal to the LEDs using pulse width modulation (PWM) values, ensuring accurate color rendition across varying temperatures by correlating temperature measurements with pre-stored light settings in the International Commission (CIE) 1931 XYZ color space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If LED lamps operate without temperature compensation, then the device complexity is reduced, but color accuracy deteriorates due to temperature variations
Solution Approach 1:
The patent implements a feedback mechanism where a thermistor continuously monitors the temperature of the LED light engine and sends this information to a controller. The controller then adjusts the PWM values for the LEDs based on the measured temperature, creating a closed-loop system that automatically compensates for temperature-induced color shifts without requiring manual intervention or complex calibration procedures.
Solution Approach 2:
The patent changes the electrical parameters (PWM values) applied to the LEDs based on temperature measurements. By storing multiple sets of PWM values corresponding to different temperature ranges and selecting the appropriate set based on real-time temperature data, the system dynamically adjusts LED output to maintain consistent color accuracy across varying operating conditions.
2Manufacturing precision
If temperature monitoring and adjustment systems are added to LED lamps, then color accuracy is improved, but device complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where a thermistor continuously monitors the temperature of the LED light engine and sends this information to a controller. The controller then adjusts the PWM values for the LEDs based on the measured temperature, creating a closed-loop system that automatically compensates for temperature-induced color shifts without requiring manual intervention or complex calibration procedures.
Solution Approach 2:
The system performs self-service by automatically monitoring its own temperature and adjusting its electrical parameters without external intervention. The thermistor and controller work together to autonomously detect temperature changes and modify PWM values accordingly, eliminating the need for manual calibration or external temperature compensation equipment.
3Stability of the object's composition
If PWM values are adjusted based on temperature, then color consistency is improved, but control complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal PWM values for different temperature conditions during the manufacturing process. Instead of performing complex real-time calculations, the controller simply retrieves the appropriate pre-computed PWM values based on the current temperature reading, significantly reducing control complexity while maintaining color consistency.
Solution Approach 2:
The patent changes the electrical parameters (PWM values) applied to the LEDs based on temperature measurements. By storing multiple sets of PWM values corresponding to different temperature ranges and selecting the appropriate set based on real-time temperature data, the system dynamically adjusts LED output to maintain consistent color accuracy across varying operating conditions.
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 solution provides consistent and accurate color output and lumens emission regardless of operating temperature, addressing the color inaccuracies caused by temperature fluctuations.
Implementation Method 1
monitoring temperature of the light engine with a thermistor. The changes in resistance measurements taken from the thermistor are correlated to changes in the temperature of the light engine
Implementation Method 2
a light engine having at least one light emitting diode
Implementation Method 3
light emitting diodes (LEDs)
Data Source
AI summary
The present disclosure provides methods and structures for controlling characteristics of light being projected from a light source. In one embodiment, the method includes selecting a color setting of light to be projected by a light engine having at least one light emitting diode; and monitoring temperature of the light engine with a thermistor. The changes in resistance measurements taken from the thermistor are correlated to changes in the temperature of the light engine. The method for controlling characteristics of light being projected from the light source may further include setting characteristics of the electrical signal to energize the light emitting diodes of the light engine to provide the color setting selected at the temperature of the light engine measured using the thermistor.