Moisture amount detection device

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Solution Overview

Problem

Conventional moisture detection devices in clothes dryers are not capable of processing moisture detection at high speeds, which hinders efficient drying of clothes.

Innovation Solution

A moisture detection device incorporating a semiconductor light emitting element that flickers at a predetermined frequency, a lock-in amplifier, and a controller that adjusts the cut-off frequency of a low-pass filter based on signal intensity, allowing for faster processing and improved signal-to-noise ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional moisture detection methods are used, then the device can detect moisture amount, but the processing speed is slow and cannot efficiently dry clothes

Engineering Contradiction:
Improvemoisture detection speedVSAvoiddrying time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The light source flickers at a predetermined frequency, and the lock-in amplifier extracts signals at this specific frequency, enabling high-speed periodic detection of moisture content during the scanning process

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent replaces conventional slow scanning detection methods with a high-speed optical detection system using flickering light sources and lock-in amplification, eliminating mechanical bottlenecks in the detection process

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If the cut-off frequency of the low-pass filter is kept low to maintain signal quality, then the signal-to-noise ratio is improved, but the processing speed decreases

Engineering Contradiction:
Improvesignal-to-noise ratioVSAvoiddetection processing speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The controller dynamically adjusts the cut-off frequency based on the detected signal intensity, creating a feedback mechanism that optimizes both signal quality and processing speed in real-time during the detection process

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The low-pass filter's cut-off frequency is made dynamically adjustable rather than fixed, allowing the system to adapt the filtering characteristics to current detection conditions and maximize both precision and speed

Inventive Principle:
Principle #15Dynamics

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

Enables faster moisture detection processing while maintaining a high signal-to-noise ratio, enhancing the efficiency of clothes drying by allowing for more precise control of drying conditions.

Implementation Method 1

a light source including a semiconductor light emitting element that emits light, the light source projecting the light toward an object, the light flickering at a predetermined frequency

Methodology Applied
Scientific EffectLight emission from semiconductor element: Light Emitting Diode

Implementation Method 2

a light receiver that receives the light reflected by the object and outputs a detection signal

Methodology Applied
Scientific EffectLight reception and signal conversion: Photoelectric Effect

Implementation Method 3

a lock-in amplifier that receives the amplified signal and outputs an extracted signal obtained by extracting a signal of the predetermined frequency from the amplified signal

Methodology Applied
Scientific EffectFrequency-selective signal extraction: Resonance

Data Source

PatentEP3677900B1Moisture amount detection device
Publication Date: 2022.09.07 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3677900B1 patent drawingFigure 1
  • EP3677900B1 patent drawingFigure 2~3A
  • EP3677900B1 patent drawingFigure 3B

AI summary

A moisture amount detection device (1) includes: a light source (10) that projects light that flickers at a predetermined frequency toward an object (2); a light receiver (30) that receives the light reflected by the object (2) and outputs a detection signal; an amplifier (40) that outputs an amplified signal obtained by amplifying the detection signal by a predetermined amplification factor; a lock-in amplifier (50) that outputs an extracted signal obtained by extracting a signal of a predetermined frequency from the amplified signal; an A/D converter (60) that performs A/D conversion on the extracted signal, and outputs a digital signal; a second low-pass filter (72) whose passband is changeable, and that allows a signal of a frequency in the passband in the digital signal to pass therethrough; and a controller (71) that performs first control to change the passband according to a signal intensity indicated by the digital signal.