High frequency heating device

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Solution Overview

Problem

Conventional high frequency heating devices face challenges in effectively shielding radio waves across a wide frequency band due to the limitations of existing radio wave shielding configurations, which can lead to radio wave leakage and compromised mechanical strength.

Innovation Solution

The proposed high frequency heating device incorporates a radio wave shielding portion with a choke groove formed from multiple conductors, featuring first and second resonance spaces with different resonance frequencies, and a dielectric choke cover to enhance radio wave shielding performance across a broader frequency range while maintaining mechanical integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a quarter-wave impedance inversion method with a choke groove is used to shield radio waves, then radio wave shielding performance is improved, but the thickness of the door increases

Engineering Contradiction:
Improveradio wave shielding performanceVSAvoiddoor thickness
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent transitions from a single linear choke groove to a two-dimensional grid pattern of multiple conductors arranged in rows and columns. This dimensional change allows the shielding function to be distributed across a broader area, reducing the required thickness in any single direction while maintaining overall shielding effectiveness through multiple reflection paths.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent divides the single choke groove into multiple segmented conductors arranged in a grid pattern. Each conductor segment acts as an independent shielding element, and their collective arrangement creates a distributed shielding network that achieves the same or better shielding performance with reduced individual component dimensions.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If the length of the choke groove is reduced to make it compact, then ease of manufacture is improved, but radio wave shielding performance deteriorates

Engineering Contradiction:
Improvecompactness of shielding structureVSAvoidradio wave shielding performance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent compensates for reduced individual conductor length by extending the shielding function into multiple dimensions through the grid arrangement. The two-dimensional distribution of multiple shorter conductors creates equivalent or superior shielding performance to a single long conductor, achieving both compactness and effectiveness.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent combines multiple conductor segments into a unified grid structure that functions as an integrated shielding system. The collective effect of multiple conductors working together in a coordinated pattern achieves the shielding performance of a single long groove while maintaining the compactness of shorter individual elements.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If a single conductor is bent multiple times to form a choke groove, then device complexity is reduced, but radio wave shielding performance across wide frequency band is limited

Engineering Contradiction:
Improvenumber of conductorsVSAvoidfrequency band coverage
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent segments the shielding function into multiple independent conductors rather than using a single continuous groove. Each conductor can be optimized for specific frequency ranges, and the collective arrangement provides broad frequency band coverage while keeping individual conductor designs simple and manufacturable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The grid arrangement of multiple conductors creates a multi-functional shielding system that effectively handles various frequency ranges and wave propagation directions simultaneously. Each conductor contributes to the overall shielding function, creating a universal solution that adapts to different operational conditions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Ease of manufacture

If choke groove is formed by bending single conductor to reduce length, then ease of manufacture is improved, but mechanical strength deteriorates

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidmechanical strength of door
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent uses multiple separate conductor segments instead of a single long bent conductor. This segmentation allows each individual conductor to be shorter and stiffer, maintaining mechanical strength while remaining easy to manufacture and install. The distributed arrangement also spreads mechanical loads across multiple points.

Inventive Principle:
Principle #1Segmentation

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

This configuration significantly reduces radio wave leakage and improves radio wave shielding performance across a wide frequency band, ensuring effective radio wave containment and maintaining the mechanical strength of the device.

Implementation Method 1

The choke groove has a first resonance space having a first resonance frequency, and a second resonance space having a second resonance frequency

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

a dielectric choke cover to enhance radio wave shielding performance

Methodology Applied
Scientific EffectDielectric: Dielectric

Data Source

PatentEP3435739B1High frequency heating device
Publication Date: 2021.07.07 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3435739B1 patent drawingFigure 1
  • EP3435739B1 patent drawingFigure 2
  • EP3435739B1 patent drawingFigure 3A

AI summary

A high frequency heating device according to the present disclosure includes: a heating chamber having an opening; an opening peripheral portion provided at a peripheral edge of the opening; a high frequency wave generation unit that supplies high frequency waves to the heating chamber; and a door that covers the opening in an openable manner and has a radio wave shielding portion at a position facing the opening peripheral portion. The radio wave shielding portion is provided with an open hole provided so as to face the opening peripheral portion, and a choke groove formed from a plurality of conductors. The choke groove has a first resonance space having a first resonance frequency, and a second resonance space having a second resonance frequency different from the first resonance frequency. Accordingly, radio wave shielding performance can be improved.