Non-Uniform LED Pulse Shaping for Life Safety Notification
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Solution Overview
Problem
Existing LED notification devices in life safety systems face a challenge in achieving higher light output while meeting Underwriter's standards without increasing power consumption, particularly when indirect viewing requirements are considered.
Innovation Solution
The implementation of a non-uniform shaping of LED light pulses with multiple intensity levels maintained for different time intervals, allowing for higher light output without increased power consumption, achieved through a processor-based control circuit that manages the power supply and LED illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If higher light output is achieved in LED notification devices, then illumination intensity is improved, but power consumption increases
Solution Approach 1:
The patent applies periodic pulsing of LED light output with multiple intensity levels (high, medium, low) within each pulse cycle. The controller alternates between these intensity levels in a repeating pattern, achieving higher peak illumination intensity while maintaining average power consumption at acceptable levels. This periodic variation allows the system to meet UL effective candela requirements through temporal distribution of energy rather than continuous high-power operation.
Solution Approach 2:
The system dynamically adjusts LED illumination intensity within each pulse cycle, transitioning between high, medium, and low intensity levels rather than maintaining a static output. This dynamic control allows the notification device to achieve higher peak light output for improved visibility while managing overall power consumption through temporal modulation of the light emission characteristics.
2Device complexity
If uniform LED pulse shape is used, then device complexity is reduced, but indirect viewing capability is insufficient
Solution Approach 1:
The controller implements periodic pulsing with multiple intensity levels (high, medium, low) within each pulse cycle. This periodic structure with varying intensity levels enhances indirect viewing capability by creating temporal contrast that improves visibility of reflected light, while the repetitive nature of the pattern keeps the control logic relatively simple and manageable.
Solution Approach 2:
The light pulse is segmented into multiple distinct intensity levels (high, medium, low) within each pulse cycle, with each level maintained for a specific duration. This segmentation of the pulse waveform into discrete intensity stages allows optimization of indirect viewing performance while keeping the control structure organized and manageable through defined temporal segments.
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 enhances light output and indirect viewing capabilities while maintaining equivalent power consumption to conventional LED notification devices, meeting UL standards and improving emergency lighting effectiveness without the need for increased power usage.
Implementation Method 1
at least one light emitting diode (LED) operable with the control circuit
Data Source
AI summary
A light emitting diode (LED) device includes a control circuit configured to apply a non-uniform output power pulse shape to increase illumination intensity in at least a part of the pulse without consuming additional power. Different intensity levels may be provided in series in the non-uniform output power pulse shape. The non-uniform output power pulse shape improves lighting while maintaining the same power consumption as a reference light pulse having a uniform shape.