Optical Attenuation Meter Using Backscattered Light
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Solution Overview
Problem
Existing optical beam attenuation meters in clear water environments provide non-repeatable and inaccurate measurements due to high attenuation lengths, requiring extensive maintenance and calibration, making them unusable for accurate measurements.
Innovation Solution
A collimated laser beam is used to propagate through water, with filtered back-scattered light recorded and analyzed by a microcomputer, optimizing beam diameter and water range to minimize scattering and maximize measurement accuracy over long paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If optical propagation paths are shortened to limit meter size, then device size is reduced, but measurement accuracy deteriorates in clear water environments
Solution Approach 1:
The patent transitions from measuring light attenuation in one dimension (direct transmission through water) to measuring backscattered light in a different dimension (returning light path). This allows the use of shorter physical propagation paths while still capturing attenuation information over effective longer paths through multiple scattering events, resolving the contradiction between compact device size and measurement accuracy in clear water.
2Length of stationary object
If attenuation length is increased in clear water, then measurement path can be extended, but maintenance effort and calibration requirements increase
Solution Approach 1:
The patent segments the measurement process into discrete, maintainable components: a laser source, optical paths with adjustable lengths, detectors, and calibration targets. This segmentation allows the system to achieve extended effective measurement paths through multiple reflections and scattering events while keeping individual physical components compact and easier to maintain and calibrate separately.
3Measurement precision
If optical propagation path is extended beyond one meter, then attenuation measurement accuracy improves, but difficulty in maintaining optical surface cleanliness increases
Solution Approach 1:
The patent introduces backscattered light as an intermediary measurement mechanism. Instead of requiring long direct optical paths that are vulnerable to contamination, the system uses shorter paths with backscattering elements that return light to the detector. This intermediary approach maintains measurement accuracy while reducing the optical path length exposed to contamination risks.
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 solution enables accurate and repeatable measurements of optical beam attenuation coefficients in clear water environments by reducing the impact of scattering and maintaining beam collimation, allowing for reliable data collection over extended propagation paths.
Implementation Method 1
a collimated beam, produced by a laser of the meter, propagates thru water or another liquid medium with filtered back-scattered light arriving at a camera of the meter
Data Source
AI summary
The present invention provides a meter and method of use for measuring an optical attenuation coefficient in a liquid medium. In operation, a collimated beam, produced by a laser of the attenuation meter apparatus, propagates thru the liquid medium with filtered back-scattered light arriving at a camera of the meter. A light image is formed at a focal plane of the camera. The light image is recorded and analyzed by a microcomputer to provide optical beam attenuations coefficients.