LED Lighting Device Color Stability via Reference Sensor Feedback
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Solution Overview
Problem
Conventional lighting devices, particularly those using incandescent and fluorescent lights, are inefficient in energy usage and have short lifespans, and solid state light emitters like LEDs face challenges in maintaining consistent color temperature and brightness over time due to degradation, which affects color rendering index and overall performance.
Innovation Solution
Incorporating a subset of solid state light emitters and a sensor within the lighting device, where reference emitters are mounted on a thermally conductive substrate, allowing for current adjustments to maintain desired luminance and color temperature by detecting intensity changes, and optionally using optical filters to protect sensors from UV radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If solid state light emitters are used to improve energy efficiency and lifespan, then energy efficiency and duration of action are improved, but color consistency and brightness stability deteriorate over time due to degradation
Solution Approach 1:
The patent incorporates reference solid state light emitters and sensors at the beginning of the device lifecycle to establish baseline color and brightness measurements. This preliminary setup enables continuous monitoring and compensation throughout the device's operation, allowing the system to maintain color consistency despite degradation of the main light emitters over time.
Solution Approach 2:
The patent implements a feedback mechanism where sensors continuously measure the color and brightness output of reference light emitters, and this information is used to adjust the driving currents of the main light emitters. This closed-loop control compensates for degradation effects, maintaining stable color rendering index and brightness output throughout the device's operational life.
2Duration of action of stationary object
If solid state light emitters are used to extend lifespan beyond conventional lighting, then duration of action is improved, but maintaining color temperature and brightness consistency becomes more difficult
Solution Approach 1:
Reference solid state light emitters are installed at the start of the device's operational life to establish baseline performance characteristics. These reference emitters remain relatively stable throughout the extended lifespan, providing a reference point for continuous compensation of the main light emitters' degradation, thereby maintaining color temperature stability over thousands of hours of operation.
Solution Approach 2:
A feedback control system continuously monitors the color temperature and brightness of reference emitters using integrated sensors. Based on these measurements, the system dynamically adjusts the current supplied to main light emitters to compensate for aging effects, ensuring reliable color temperature stability throughout the extended operational lifespan of the lighting device.
3Adaptability or versatility
If reference emitters and sensors are integrated into the lighting device, then color control capability is improved, but device complexity increases
Solution Approach 1:
The patent combines reference solid state light emitters, sensors, and control circuitry into an integrated lighting device module. This merging of components into a unified system reduces the overall complexity compared to separate systems, while maintaining advanced color control capabilities through the协同 work of these integrated elements.
Solution Approach 2:
The reference light emitters serve multiple functions: they provide color reference for measurement, act as additional light sources for illumination, and enable long-term stability compensation. This multi-functionality reduces the need for separate dedicated reference components, thereby reducing overall device complexity while maintaining color control capabilities.
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 solution ensures consistent color temperature and brightness of white light emission over time, extending the lifespan of lighting devices and improving energy efficiency by compensating for degradation through intelligent current management and sensor feedback systems.
Implementation Method 1
Light emitting diodes are semiconductor devices that convert electrical current into light
Implementation Method 2
detecting an intensity of light from the first group reference solid state light emitter
Implementation Method 3
reference emitters are mounted on a thermally conductive substrate
Data Source
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AI summary
A lighting device comprising a group of one or more illumination solid state light emitters, a reference solid state light emitter and a reference sensor which detects an intensity of the reference solid state light emitter. Each of the emitters (1) has an illumination which is spaced from a first point by a delta u', v' distance on a 1976 CIR diagram of not more than 0.015, and/or (2) has a forward voltage temperature dependence which is within 5 % of a first forward voltage temperature dependence. In addition, a lighting device comprising one or more illumination solid state light emitters, a reference solid state light emitter and a sensor which comprises at least two areas of individual sensors. Also, methods of lighting.