LED Lighting System Time Division Ambient Light Sensing
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Solution Overview
Problem
Current lighting systems that use light emitting diodes (LEDs) for light harvesting do not accurately account for the brightness of ambient light due to the contribution of artificial light from LEDs to the ambient light sensor, leading to inaccurate adjustments in brightness.
Innovation Solution
A lighting system that employs time division light output sensing and adjustment, where the power to LEDs is modulated for a short duration to allow ambient light sensors to accurately sense brightness without human perception, and the controller adjusts the LED brightness based on target values to complement natural light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ambient light sensor is placed on exterior of lamp housing to minimize artificial light contribution, then measurement precision of ambient light is improved, but device complexity increases due to remote communication requirements
Solution Approach 1:
The patent segments the light sensing function by separating ambient light detection from artificial light emission in time domains. The LED driver circuit is divided into LED driving mode and ambient light sensing mode, allowing the same sensor to measure ambient light accurately without contamination from the LED source by alternating between these modes temporally.
Solution Approach 2:
The system employs periodic action by alternating between LED driving and ambient light sensing in a cyclic manner. The controller switches between these modes periodically, enabling the sensor to repeatedly measure ambient light levels without the interference of LED emission, thus achieving accurate measurement while maintaining system functionality.
2Illumination intensity
If LED current is increased to boost brightness, then illumination intensity is improved, but energy consumption increases
Solution Approach 1:
The patent applies periodic action by using duty cycle modulation to control LED operation. The LED driver circuit alternates between driving LEDs at full current for illumination and reducing current to zero for sensing, creating a periodic on-off pattern that reduces average power consumption while maintaining required illumination levels during active periods.
Solution Approach 2:
The system dynamically adjusts LED current based on operational mode and ambient conditions. The controller modifies the drive current in real-time, increasing it when illumination is needed and reducing it during sensing phases, enabling adaptive energy management that balances brightness requirements with power consumption.
3Adaptability or versatility
If LED brightness is adjusted continuously to match ambient light changes, then adaptability of lighting system is improved, but device complexity increases due to continuous control requirements
Solution Approach 1:
The patent implements feedback by using the ambient light sensor to continuously monitor environmental light levels and feed this information back to the controller. The controller then adjusts LED drive current based on this feedback signal, creating a closed-loop control system that automatically adapts lighting output to match ambient conditions without requiring complex manual intervention.
Solution Approach 2:
The lighting system performs self-service by automatically adjusting its own brightness levels in response to ambient light changes. The integrated sensor-controller-LED feedback loop enables the system to self-regulate and adapt to environmental conditions autonomously, eliminating the need for external manual control mechanisms.
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 enables precise adjustment of LED brightness to match target values, effectively eliminating the contribution of artificial light to ambient light sensing, resulting in improved light harvesting and a more accurate control of lighting conditions.
Implementation Method 1
receive a signal from a sensor indicating a brightness of light received by the sensor
Data Source
AI summary
A lighting system includes time division light output sensing and adjustment for ambient light. In at least one embodiment, time division light output sensing involves modulating power to a light emitting diode (LED) set, and the set of LEDs includes one or more LEDs. In at least one embodiment, each LED in the LED set is included in a single lamp, and, in at least one embodiment, the set of LEDs is contained in multiple lamps. In at least one embodiment, for each lamp, a controller modulates power to the LED set by selectively reducing power to the LED set using time division algorithm to allow a light sensor to sense the brightness of ambient light with a reduced contribution from the LED set. In at least one embodiment, a lighting system also includes time division light output sensing and adjustment for different spectra LEDs.