Water Quality Sensor Using Positive Feedback for Trace Detection
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Solution Overview
Problem
Conventional water quality sensing systems have poor limit of detection (LOD) characteristics, making it difficult to detect trace amounts of substances, which limits their sensitivity and accuracy.
Innovation Solution
A sensing system incorporating an optical actuator, a photo detector, an amplifier, and a detection unit configured to provide positive feedback, allowing for the detection of trace amounts of substances by amplifying electrical signals and maintaining a stable optical stimulus, enabling the detection of trace amounts of substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional sensing system uses single-ended signal scheme and negative feedback configuration, then the structure is more stable, but the limit of detection (LOD) characteristic is poor and cannot detect trace amounts of substances
Solution Approach 1:
The patent applies positive feedback configuration instead of conventional negative feedback. The sensing system includes a feedback path that feeds back a portion of the output signal to the input, creating a regenerative effect that amplifies weak signals from trace substances. This positive feedback mechanism enables the system to detect substances at concentrations below the conventional LOD while maintaining structural stability through controlled feedback gain.
2Measurement precision
If an amplifier is added to amplify the electrical signal, then the sensitivity and LOD characteristic are improved, but the device complexity increases
Solution Approach 1:
The patent merges the amplifier function with the existing sensing components by integrating signal amplification into the feedback loop. Rather than adding a completely separate amplification stage, the system combines the photo detector, amplifier, and feedback path into a unified sensing architecture where the amplifier operates as part of the feedback mechanism, thereby reducing overall system complexity while achieving high sensitivity.
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 system effectively detects trace amounts of substances that are difficult to detect with conventional sensors, improving sensitivity and accuracy by utilizing a positive feedback mechanism to enhance signal detection and analysis.
Implementation Method 1
a photo detector configured to output an electrical signal having a snapback form in response to an optical response generated according to a concentration of the detection target substance to which the optical stimulus is applied
Implementation Method 2
an amplifier configured to amplify the electrical signal output from the photo detector and to provide the amplified electrical signal as positive feedback to the optical actuator
Data Source
AI summary
A sensing system according to the embodiment of the present invention includes an optical actuator configured to apply an optical stimulus into a detection target substance, a photo detector configured to output an electrical signal having a snapback form in response to an optical response generated according to a concentration of the detection target substance to which the optical stimulus is applied, an amplifier configured to amplify the electrical signal output from the photo detector and to provide the amplified electrical signal as positive feedback to the optical actuator, and a detection unit configured to detect the detection target substance in response to the electrical signal.