Emergency Lighting Detection Using Photodiode and Telephoto Lens
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Solution Overview
Problem
Existing emergency and safety lighting systems face challenges in reliably detecting flashing patterns from lamps due to ambient light saturation and difficulty in isolating the pattern from the background, especially when the lamps are far away, using image sensors like CCD or CMOS in mobile phones.
Innovation Solution
The use of a photodiode as a photodetector with a telephoto lens and lens hood, along with a laser beam source and a tube structure to reduce ambient light, and a vibration element for haptic confirmation, enhances the robustness and ease of use in detecting flashing patterns, and a wireless or wired connection to a control center for data communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If image sensors (CCD or CMOS) are used in mobile phones to detect flashing patterns, then image resolution and depth of field are improved, but sensor saturation due to ambient light occurs when detecting distant lamps
Solution Approach 1:
The patent changes the photodetector type from image sensors to photodiodes, which have different spectral and temporal response characteristics. Photodiodes have faster response times and are less prone to saturation from ambient light, enabling reliable detection of flashing patterns from distant emergency lights without the saturation problems that plague high-resolution image sensors
Solution Approach 2:
The patent replaces the mechanical/image sensor-based detection system with an optoelectronic photodiode system. This substitution enables direct optical-to-electrical signal conversion with superior temporal response characteristics, allowing the device to capture rapid flashing patterns without the lag and saturation issues inherent in image sensor systems
2Measurement precision
If image sensors with high image resolution are used, then depth of field is improved, but it becomes more difficult to isolate a lamp emitting a flashing pattern from a background
Solution Approach 1:
The patent detects periodic flashing patterns from emergency lights rather than attempting to capture static images. By synchronizing detection with the periodic nature of the flashing signal and using photodiodes with fast response times, the system can isolate the periodic flashing signal from non-periodic ambient background light, solving the pattern isolation problem that plagues image sensor approaches
3Reliability
If a photodiode is used as the photodetector, then robustness against ambient light is improved, but sensor saturation due to flickering lighting means may still occur
Solution Approach 1:
The patent employs signal processing that analyzes the temporal characteristics of the detected signal. By identifying periodic flashing patterns and distinguishing them from non-periodic ambient flicker, the system can filter out harmful flickering effects while preserving the emergency light signal, thereby preventing saturation from unwanted light sources
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 allows for reliable and stable detection of flashing patterns from emergency and safety lights, regardless of their position, reducing sensor saturation and improving handling, while maintaining a long service life and facilitating data communication with control centers.
Implementation Method 1
the device comprises an optoelectronic device with a photodetector... Since a photodiode, in particular a PIN photodiode, forms the photodetector, the device can be designed to be particularly robust with respect to ambient light
Implementation Method 2
The lens can have a converging lens, held in particular in the tube, whose focal point lies on the sensor surface of the photodetector
Implementation Method 3
The detection of a flashing pattern - even with lights that are comparatively far away - can be further facilitated if the device has a laser beam source
Data Source
Figure 1
Figure 2
AI summary
An emergency and/or safety lighting system is shown, comprising at least one luminaire (2a, 2b), in particular an emergency and/or safety luminaire, which has at least one light source (5a, 5b) for emitting an optically, in particular visually, detectable flashing pattern (4a, 4b), and a device (3) for optically detecting the flashing pattern (4a, 4b), wherein the device (3) comprises an optoelectronic device (9) with a photodetector (10) and with a lens (11). In order to detect the flashing pattern of the luminaire (2a, 2b) reliably – regardless of the position of a luminaire (2a, 2b) of the emergency and/or safety lighting system (1) – it is proposed that a photodiode (10a), in particular a PIN photodiode, forms the photodetector (10).