Fiber Optic Ambient Light Sensor Integration in LED Fixtures
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Solution Overview
Problem
Existing lighting control systems using external photo-sensors for daylight harvesting face issues such as high cost, large component size, and the need for separate power and communication interfaces, which are difficult to integrate with LED light fixtures due to the interference from electrical light.
Innovation Solution
Incorporating an ambient light sensor within the light fixture's housing, connected via a fiber optic light pipe to measure ambient light conditions, allowing for remote or external measurement without direct exposure to electrical light, and using a switching circuit and controller to regulate lighting output based on ambient light levels, with optional wireless communication for remote control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an ambient light sensor is mounted directly on the LED module PCB, then integration is simplified, but measurement precision deteriorates due to interference from electrical light
Solution Approach 1:
The system separates the light sensing function from the LED module by using a dedicated sensor mounted in the fixture housing, isolated from the electrical light source. This segmentation allows the sensor to measure ambient light without interference from the LED module's electrical light.
Solution Approach 2:
The patent introduces an intermediary ambient light sensor positioned in the fixture housing that acts as a mediator between the ambient light environment and the control system. This intermediary component enables accurate ambient light measurement while maintaining electrical isolation from the LED module.
2Measurement precision
If external photo-sensors are used for ambient light measurement, then measurement precision is improved, but device complexity increases due to separate power and communication interfaces
Solution Approach 1:
The patent combines the ambient light sensor with the existing fixture housing structure, merging the sensing function into the fixture itself rather than using completely external sensors. This integration leverages existing power and control infrastructure, reducing the need for separate power sources and communication interfaces.
Solution Approach 2:
The fixture housing serves multiple functions: it houses the LED module, provides structural support, and acts as the mounting location for the ambient light sensor. This multi-functionality reduces the need for additional external components and simplifies system integration.
3Measurement precision
If external photo-sensors are mounted away from the LED fixture, then measurement precision is improved, but ease of operation deteriorates due to separate mounting and wiring requirements
Solution Approach 1:
The ambient light sensor is integrated into the fixture housing assembly, combining the sensing function with the existing fixture structure. This merger eliminates the need for separate mounting procedures and wiring connections, as the sensor utilizes the fixture's existing power and control infrastructure.
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 simplifies the integration of ambient light measurement into LED fixtures, reduces mechanical changes, and enhances energy efficiency by allowing for precise control of lighting output while minimizing the need for external sensors and wiring, thus addressing the limitations of traditional systems.
Implementation Method 1
An ambient light channel (e.g., a fiber optic light pipe) extends from the ambient light sensor to an aperture between the outer surface of the housing and the inner surface of the housing
Data Source
AI summary
A lighting control system for a light fixture has an ambient light sensor mounted therein. A switching circuit provides power for driving lighting sources. A controller receives signals from the light sensor and regulates switching frequencies based on desired lighting output level and the ambient light condition. An ambient lighting channel extends from the ambient light sensor to an aperture between outer and inner surfaces of the housing. The ambient lighting channel may include a fiber optic light pipe which extends from the aperture to surround the light sensor. The fiber optic light pipe may extend through the aperture from the ambient light sensor to an ambient light source external to the light fixture. The light sensor may mount on a shared PCB with respect to the lighting sources, such as an LED array, and transmit ambient lighting information to the controller via a feedback loop.