Internal UV LED Biofouling Prevention for Underwater Optical Windows
Solution Overview
Problem
Existing methods for reducing biofouling in marine environments, such as using UV light, are hindered by obstructive light sources, attenuated UV intensity, and high power consumption, particularly in optical sensors and cameras that require clear windows for prolonged periods without mechanical cleaning.
Innovation Solution
An apparatus with internal UV LEDs emitting between 250-400 nanometers, positioned behind a UV-transparent window, uses a controller to cyclically activate UV light at varying power levels, minimizing energy consumption by employing short high-power flashes followed by longer low-power or no UV light periods, thus reducing biofouling effectively while maintaining optical clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If UV light sources are positioned outside housings to irradiate underwater surfaces, then biofouling prevention is achieved, but the light sources obstruct the view and parts of the window remain in shade where biofouling still occurs
Solution Approach 1:
Instead of positioning UV light sources outside the housing as conventional apparatuses do, the patent inverts the arrangement by placing UV LEDs inside the housing behind the window. This internal positioning eliminates view obstruction and shadowing problems while still achieving effective biofouling prevention through the UV-transparent window.
Solution Approach 2:
The patent introduces a UV-transparent window as an intermediary element that allows UV light to pass from the internal light source to the external underwater environment. This mediator enables the UV light to reach the window surface for biofouling prevention while keeping the light source positioned inside the housing, avoiding view obstruction.
2Object-affected harmful factors
If UV light travels through water to reach the window, then external irradiation is possible, but UV intensity is attenuated
Solution Approach 1:
The patent extracts the UV light source from the external environment and positions it inside the housing, eliminating the need for UV light to travel through water. This removes the attenuation problem entirely, as the UV LEDs now illuminate the window directly from inside without water interference.
3Object-affected harmful factors
If conventional UV apparatuses are used in offshore environments, then biofouling prevention is provided, but power consumption is high and power delivery is challenging
Solution Approach 1:
Instead of continuous UV illumination, the patent employs periodic pulsed operation where UV LEDs are activated in cycles. This periodic action maintains biofouling prevention effectiveness while dramatically reducing average power consumption, making the system suitable for offshore environments with limited power availability.
Solution Approach 2:
The patent changes the operational parameters of UV LEDs by controlling their duty cycle and pulse width. By adjusting these parameters, the system achieves effective biofouling prevention with optimized power consumption, adapting to the constraints of offshore power delivery.
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 significantly reduces biofouling on underwater optical devices by minimizing energy consumption, extending their operational life and maintaining clear windows with reduced power usage, even in deep-sea environments, while avoiding external light source obstructions and intensity attenuation.
Implementation Method 1
The recent development of ultra violet (UV) light emitting diodes (UV LEDs), such as those comprising aluminum nitride, have made available the option to use generated UV light to kill microbes on and near surfaces to be protected against biofouling.
Implementation Method 2
use generated UV light to kill microbes on and near surfaces
Implementation Method 3
An apparatus with internal UV LEDs emitting between 250-400 nanometers, positioned behind a UV-transparent window
Data Source
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AI summary
Techniques for reducing biofouling on optical equipment, using minimum power in a marine environment are provided. An example of an apparatus according to the disclosure includes a housing including a cavity and an ultraviolet transparent window disposed over the cavity, an optical device disposed in the cavity and directed towards the ultraviolet transparent window, one or more ultraviolet light emitting diodes disposed in the cavity and directed towards the ultraviolet transparent window, and a controller operably coupled to the one or more ultraviolet light emitting diodes and configured to provide at least one lamp power function to the one or more ultraviolet light emitting diodes, wherein the at least one lamp power function is based on at least a flash power value, a flash duration, a rest power value and a rest duration.