LED Light Bar IR Pulse Traffic Preemption
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Solution Overview
Problem
Conventional strobe tube emitters used in traffic control preemption systems require significant power, generate unnecessary light bandwidths, and degrade over time, reducing their effectiveness in activating traffic signals for emergency vehicles.
Innovation Solution
The use of a light bar with multiple LED modules, including both infrared (IR) and visible LEDs, where a controller triggers IR light pulse patterns to activate preemption in traffic control systems, maintaining consistent IR radiant power through current control and feedback mechanisms, reducing power consumption and degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional strobe tube emitters are used to generate light pulses for traffic control preemption, then sufficient radiant power can be detected from over 2500 feet away, but significant power is consumed and broad spectrum light is generated which includes unnecessary light bandwidths
Solution Approach 1:
The patent extracts only the necessary near-infrared bandwidth from the broad spectrum light, using an optical filter on the detector to restrict sensitivity to only the near-infrared range. This eliminates unnecessary light bandwidths while maintaining sufficient radiant power detection capability.
Solution Approach 2:
The patent changes the operating parameters by using pulsed light emission at predetermined rates (10 Hz or 14 Hz) rather than continuous emission, and by filtering to specific wavelengths. This allows sufficient radiant power to be delivered in concentrated pulses while reducing overall power consumption compared to continuous broad-spectrum emission.
2Illumination intensity
If conventional strobe tube emitters are used to generate light pulses for traffic control preemption, then sufficient radiant power can be detected from over 2500 feet away, but the emitters degrade over time reducing their effectiveness
Solution Approach 1:
The patent employs LED emitters that, while having finite lifetimes, provide consistent performance throughout their operational life without the degradation characteristics of strobe tubes. The modular LED design allows for easier replacement and maintains reliable radiant power output throughout its service life.
3Measurement precision
If an optical filter is used on the detector to restrict sensitivity to near infrared spectrum, then interference from other sources of light is minimized, but the detector can only detect light in the near infrared range
Solution Approach 1:
The patent applies local quality by making the detector's sensitivity specific to the near-infrared wavelength range where the LED emitter operates. This localized spectral sensitivity maximizes detection accuracy for the intended application while filtering out other wavelengths that would cause interference.
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 enhances the reliability and efficiency of traffic control preemption systems by reducing power usage, minimizing unnecessary light generation, and maintaining consistent IR intensity, thereby improving the activation distance and response time for emergency vehicles.
Implementation Method 1
Each LED module includes a plurality of LED groups, and in at least one of the plurality of LED modules, at least one LED group in the module is an infrared (IR) LED group
Implementation Method 2
at least one LED group in the module is an infrared (IR) LED group, and at least one LED group in the module is a visible light LED group
Implementation Method 3
maintaining consistent IR radiant power through current control and feedback mechanisms
Data Source
AI summary
Various approaches for activating a traffic control preemption system. A light bar includes a support structure and a plurality of LED modules individually mounted on the support structure. Each LED module includes a plurality of LED groups, and in at least one of the plurality of LED modules, at least one LED group in the module is an infrared (IR) LED group, and at least one LED group in the module is a visible light LED group. A controller is coupled to each module. The controller is configured to trigger an IR light pulse pattern at a first level of IR radiant power from the at least one IR LED group. The pulse pattern and first level of IR radiant power activate preemption in a traffic control preemption system.