Emergency LED Lighting Dimming Control for Energy Conservation
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Solution Overview
Problem
Conventional emergency lighting systems face challenges in reducing power consumption without compromising visibility, as filament-based systems dim and shift in color temperature, while LED-based systems maintain constant power levels, limiting further energy conservation and visibility.
Innovation Solution
An emergency lighting system utilizing LEDs that dim with minimal color shift, controlled by a controller reducing power over time, along with a circuit to detect AC power absence and manage emergency power sources like batteries or capacitors, ensuring scotopically enhanced visibility and energy conservation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If power to LED is reduced to conserve energy, then power consumption is reduced, but visibility deteriorates
Solution Approach 1:
The patent applies dynamics by transitioning from static constant-power LED operation to dynamic time-varying power control. The controller adjusts LED power consumption as a function of time during emergency operation, initially providing high visibility and then gradually reducing power to extend battery life while maintaining adequate illumination.
Solution Approach 2:
The patent implements periodic action through a two-stage power delivery pattern: an initial high-power period for immediate visibility upon emergency detection, followed by a reduced-power period for extended duration operation. This periodic power adjustment optimizes both visibility and energy conservation.
2Use of energy by moving object
If filament bulb power is reduced, then power consumption is reduced, but color temperature shifts to red and visibility deteriorates
Solution Approach 1:
The patent replaces traditional filament bulbs with LED technology, which has a fundamentally different operational characteristic: LEDs maintain stable color temperature across varying power levels unlike filament bulbs. This substitution eliminates the color shift problem while still achieving energy conservation through controlled dimming.
3Use of energy by moving object
If LED power is maintained at constant reduced level, then energy conservation is achieved, but further power reduction is limited
Solution Approach 1:
The patent transitions from static constant-power operation to dynamic time-varying power control, allowing the system to optimize both energy conservation and duration. By adjusting power as a function of time rather than maintaining a fixed reduced level, the system achieves extended emergency lighting duration while maintaining adequate visibility when needed.
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 effectively reduces power consumption while maintaining visibility by gradually dimming LEDs with minimal color shift, extending emergency lighting duration and allowing smaller, less expensive energy storage solutions.
Implementation Method 1
a light source comprising at least one LED configured to dim with very little to no color shift when power thereto is reduced
Data Source
AI summary
System and method are provided for controlling emergency lighting where emergency lights turn on when main source of power goes out for controlling emergency lighting to conserve energy utilized by the emergency light, while maintaining good visibility of the emergency lighting. Solid state lighting, such as LED, is used within an emergency light to add light in blue wavelength region matching the light output to the most sensitive of wavelength response of the human eve to increase color perception and allows faster response time. Electrical current to the device and light output are reduced while LED light tends to increase its blue wavelength component as it is dimmed thus increasing effective light output. After a predetermined time, the light is purposefully dimmed to conserve energy and to allow the eye to slowly and safely adjust to the new lighting conditions. By reducing electrical current, energy storage batteries may be smaller than for similar unit that maintains constant light output.