Microwave Heating Device Reflected Wave Detection

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Solution Overview

Problem

Conventional microwave heating devices lack accurate detection of the state of an object being heated, particularly during the thawing process, due to the influence of standing-wave stabilizing parts on microwave absorption and reflection patterns.

Innovation Solution

A microwave heating device with a reflected-wave detection unit positioned closer to the heating chamber than the standing-wave stabilizing part, allowing for accurate detection of changes in microwave absorption and reflection patterns, which indicate the thawing state of the object.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a standing-wave stabilizing part is provided in the waveguide, then the positional disturbance of the in-tube standing wave is suppressed and uniform heating is achieved, but the detection accuracy of the object state during heating deteriorates

Engineering Contradiction:
Improvestanding wave position stabilityVSAvoidobject state detection accuracy
Core Design Contradiction:
Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The waveguide is segmented into two functional zones: a first waveguide section containing the standing-wave stabilizing part for maintaining stable microwave propagation, and a second waveguide section free of such parts for accurate reflected wave detection. This spatial segmentation allows each zone to optimize its specific function without interference from the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The reflected wave detection unit is extracted from the first waveguide section containing the standing-wave stabilizing part and relocated to the second waveguide section. This extraction eliminates the interference between the stabilizing part and the detection unit, enabling accurate detection of object state changes during heating.

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If the reflected-wave detection unit is positioned close to the heating chamber, then the detection accuracy of reflected waves improves, but the influence of the standing-wave stabilizing part on the detection increases

Engineering Contradiction:
Improvereflected wave detection accuracyVSAvoidstanding wave interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The waveguide is divided into a first waveguide section with the standing-wave stabilizing part and a second waveguide section without it. The reflected-wave detection unit is placed in the second section, creating a spatial separation that eliminates the harmful interference from the stabilizing part while maintaining close proximity to the heating chamber for accurate detection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second waveguide section acts as an intermediary zone between the heating chamber and the reflected-wave detection unit. This intermediate section free of standing-wave stabilizing parts serves as a clean detection path, allowing accurate measurement of reflected waves without direct interference from the stabilizing structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 precise detection of the thawing state and temperature changes, allowing for optimized heating control and reduced thawing time, independent of the object's weight or shape.

Implementation Method 1

a microwave generating unit to generate a microwave, a waveguide to cause the microwave to propagate to the heating chamber

Methodology Applied
Scientific EffectDielectric heating: Dielectric Heating

Implementation Method 2

a reflected-wave detection unit disposed closer to the heating chamber than the standing-wave stabilizing part in a direction of transmission of the microwave, and detecting a part of a reflected wave which is a microwave that returns from the heating chamber to the microwave generating unit

Methodology Applied
Scientific EffectMicrowave reflection: Reflection

Data Source

PatentEP3784002B1Microwave heating device
Publication Date: 2022.05.04 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3784002B1 patent drawingFigure 1
  • EP3784002B1 patent drawingFigure 2
  • EP3784002B1 patent drawingFigure 3

AI summary

A microwave heating device according to the present disclosure includes: a heating chamber to accommodate a heating target object, a microwave generating unit to generate a microwave, a waveguide, a standing-wave stabilizing part, and a reflected-wave detection unit. The waveguide transmits, to the heating chamber, the microwave generated by the microwave generating unit. The standing-wave stabilizing part stabilizes the position of an in-tube standing wave that occurs in the inside of the waveguide. The reflected-wave detection unit is disposed closer to the heating chamber than the standing-wave stabilizing part, and detects a part of a reflected wave which is a microwave that returns from the heating chamber to the microwave generating unit.