Induction Heating Sensor Light Guide for Accurate Temperature Detection

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Solution Overview

Problem

In induction heating appliances, the temperature control of empty pots with low thermal conductivity and heat capacity can lead to uneven heating, causing the bottom to overheat and potentially deform, and the infrared sensor arrangement can be offset, leading to inaccurate temperature detection, especially in dark environments where the infrared incident region is hard to notice.

Innovation Solution

The infrared sensor and light emitting element are positioned below the top plate, with the light emitting element illuminating the infrared incident region, making it visible and ensuring that infrared rays from the pot are efficiently guided to the sensor for accurate temperature control, even in dark environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the infrared sensor is arranged at the center of the heating coil, then the temperature detection is simplified, but the detection accuracy deteriorates due to offset from the infrared incident region

Engineering Contradiction:
Improvesensor arrangement complexityVSAvoidtemperature detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces a light guide portion that redirects infrared rays from the heating coil center to the infrared sensor positioned at the top plate center. This creates an optical path in a different spatial dimension, allowing the sensor to remain at the simple central location while accurately detecting temperature through the light guide mechanism.

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

2Measurement precision

If the infrared sensor is positioned to accurately detect the heating coil center, then the temperature detection accuracy improves, but the device complexity increases due to offset arrangement

Engineering Contradiction:
Improvetemperature detection accuracyVSAvoidsensor arrangement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The light guide portion acts as an intermediary element between the heating coil center and the infrared sensor. It transfers infrared radiation from the heating zone to the sensor position, enabling accurate temperature detection without requiring the sensor to be physically positioned at the heating coil center.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If the infrared incident region is not illuminated, then the device structure is simpler, but the ease of operation deteriorates in dark environments

Engineering Contradiction:
Improveillumination system complexityVSAvoiduser awareness of incident region
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent applies illumination to the infrared incident region, making it visually distinguishable from surrounding areas. This helps users identify the correct placement zone for the cooking vessel bottom, ensuring proper alignment with the heating coil and sensor detection area.

Inventive Principle:
Principle #32Color changes

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 allows for reliable and efficient temperature control of the pot, preventing overheating and ensuring accurate detection, even when the environment is dark, by making the infrared incident region easily noticeable and ensuring the infrared rays are directed to the sensor.

Implementation Method 1

an infrared sensor for detecting infrared rays radiated from the article to be heated

Methodology Applied
Scientific EffectInfrared radiation detection: Infrared Radiation

Implementation Method 2

a light emitting element for emitting light

Methodology Applied
Scientific EffectLight emission: Light Emitting Diode

Implementation Method 3

first and second heating coils arranged below a front portion of the top plate

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 4

induction heating appliance for induction heating a material to be heated

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Data Source

PatentEP2096897B1Induction heating cooking device
Publication Date: 2017.11.22 PANASONIC HOLDINGS CORP
  • EP2096897B1 patent drawingFigure 1
  • EP2096897B1 patent drawingFigure 2
  • EP2096897B1 patent drawingFigure 3

AI summary

An infrared sensor 40 for detecting infrared rays of light and a light emitting element 54 are disposed below a light transmittable top plate 4a, which has a hearing area for heating an article to be heated A placed thereon, in juxtaposed fashion relative to each other, so that infrared rays of light radiated from the article to be heated A may be guided towards the infrared sensor 40. A light guide portion 36a is provided for guiding rays of flight, emitted from the light emitting element, towards a heating area of the top plate 4a, and the rays of light emitted from the light emitting element 54 and guided by the light guide portion 36a are projected onto the top plate 4a through an upper opening 36d of the light guide portion 36a so that such rays of light can be noticed with eyes within the heating area 35.