Light Guide Reflection Element for Compact Cooktop Temperature Sensing

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Solution Overview

Problem

Existing cooktops with infrared sensors for temperature determination face challenges in achieving a compact design due to the need for extensive installation space for optical fibers and bending radii, which limits their space-saving and measurement accuracy.

Innovation Solution

The integration of a light guide unit with an optical fiber and a light reflection element, including a metal coating or total reflection prism, allows for efficient light guidance and reflection, reducing the need for extensive installation space and enhancing measurement accuracy by minimizing scattered light and using a focusing element to image the measuring point onto the light sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If optical fibers are used to guide light from measuring point to sensor module, then light transmission is achieved, but installation space requirements increase due to minimum bending radii

Engineering Contradiction:
Improvelight transmissionVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

A light reflection element is introduced as an intermediary component between the measuring point and the sensor module. This element redirects light paths using reflection rather than requiring long optical fiber runs with bending radii, thereby reducing installation space while maintaining reliable light transmission.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical bending of optical fibers with an optical reflection mechanism. Instead of physically routing fibers around corners with minimum bending radii, light is reflected off a surface element to achieve the same directional change, eliminating space constraints imposed by fiber bending requirements.

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

2Measurement precision

If optical fibers are routed extensively to achieve measurement, then light guidance is maintained, but device compactness is reduced

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoiddevice volume
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The light reflection element utilizes angular/directional dimension to redirect light paths. Instead of extending optical fibers linearly across the device volume, light is reflected at specific angles to reach the sensor, effectively using spatial orientation rather than linear distance to achieve measurement functionality.

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

3Adaptability or versatility

If light is guided through extended paths, then measurement coverage is improved, but scattered light increases reducing measurement accuracy

Engineering Contradiction:
Improvemeasurement coverageVSAvoidmeasurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The light reflection element is positioned and oriented to reflect light from specific measurement locations directly to the sensor module. This localized reflection approach maintains measurement coverage for different positions while ensuring that each reflected path minimizes scattered light exposure, preserving measurement accuracy.

Inventive Principle:
Principle #3Local quality

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 achieves a compact, space-saving design with improved measurement accuracy and high light intensity in the light sensor module, enabling precise temperature determination in cooking devices and other household appliances.

Implementation Method 1

which is intended to guide light from a measuring point to the light sensor module

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

the light guide unit has at least one light reflection element

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2704522B1Domestic appliance
Publication Date: 2018.02.28 BSH HAUSGERATE GMBH
  • EP2704522B1 patent drawingFigure 1
  • EP2704522B1 patent drawingFigure 2
  • EP2704522B1 patent drawingFigure 3

AI summary

The household appliance device (12) has a sensor unit (20), which has a light sensor module (22) and a light guide unit (24). The light guide unit comprises optical fibers (26) and is provided to guide light from a measurement point (30) to the light sensor module. The light guide unit comprises a light reflection element (32) with a metal coating, where the light reflection element is designed as a total reflection element. The optical fiber is optically arranged between the light reflection element and a light sensor.