Liquid presence/turbidity sensor using single optical channel
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Solution Overview
Problem
Current optical sensors with a single channel cannot reliably distinguish between air and turbid water due to similar light attenuation levels, making it difficult to measure turbidity and detect liquid presence accurately.
Innovation Solution
A turbidity sensor using a single optical channel with refractive elements that focus light differently in air versus water, allowing for distinct light transmission levels based on the index of refraction, enabling unambiguous differentiation between air and water of varying turbidities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single optical channel is used to measure turbidity, then device complexity is reduced, but the ability to distinguish between air and turbid water deteriorates
Solution Approach 1:
The patent changes the optical parameters by introducing refractive elements (lenses) that focus light differently depending on the medium (air vs. water). The focusing element creates distinct light transmission levels based on the index of refraction difference, enabling the single optical channel to distinguish between air and water by detecting different light intensity levels at the photodetector
Solution Approach 2:
The refractive element acts as an intermediary between the light source and photodetector, modifying the light path based on the medium present. The element's refraction properties create different optical paths for air versus water, allowing the system to differentiate between the two media through a single optical channel
2Measurement precision
If optical elements are configured to maximize light transmission in liquid, then measurement precision for turbidity is improved, but the ability to distinguish air from liquid deteriorates
Solution Approach 1:
The system uses refractive elements that exploit the parameter difference in index of refraction between air and water. By designing lenses that focus light optimally in air but create defocusing or different focal patterns in water, the system generates distinct light transmission signatures that allow reliable differentiation while maintaining turbidity measurement capability
Solution Approach 2:
Instead of trying to make the optical system work equally well for both air and water detection, the patent inverts the approach by designing the optical elements to create maximally different behaviors for the two media. The refraction-based focusing creates opposite or distinctly different light transmission patterns, making it easier to distinguish between air and liquid presence
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 allows for reliable detection of liquid presence and turbidity using a single optical channel, reducing parts count and enabling multiple control purposes within appliances by distinguishing between air, clear water, and turbid water with high accuracy.
Implementation Method 1
at least one optical element is positioned along the optical path in contact with the fluid to change the transmission of light between the electronic light source and electronic light detector as a function of an index of refraction of the fluid relative to material of the optical element
Data Source
AI summary
A multisensor employs an optical system that is modified by the index of refraction of fluid passing between a light emitter and light detector to successfully distinguish between air and water (of any turbidity) and between water of different turbidity values. The optical system may employ lenses contacting the fluid to change their focal length and thus to focus and defocus light on the light detector depending on an index of refraction of the fluid.