Optical Toast Browning Control Using Reflected Light Feedback
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Solution Overview
Problem
Conventional toasting appliances face challenges in accurately controlling the degree of browning of toast due to variations in foodstuff nature and ambient conditions, leading to inconsistent results.
Innovation Solution
A toasting appliance equipped with an optical system that illuminates and detects the foodstuff using a monochromatic light source, adjusting the illumination intensity to maintain a set value before toasting begins, and terminating the process based on desired browning levels, ensuring consistent results regardless of initial conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If time-based control is used to activate heating elements, then the toasting operation is simple to control, but the degree of browning varies depending on foodstuff nature, moisture content, and ambient temperature
Solution Approach 1:
The patent replaces the mechanical time-based control system with an optical detection system. A light source illuminates the foodstuff, and a light detector measures the reflected light intensity. The system terminates toasting when the reflected light intensity reaches a predetermined threshold, directly controlling the browning degree rather than relying on time-based estimates.
Solution Approach 2:
The patent implements a feedback control mechanism where the light detector continuously monitors the reflected light intensity from the foodstuff during toasting. This real-time feedback allows the system to adjust and terminate the heating process precisely when the desired browning level is achieved, ensuring consistent results regardless of variations in foodstuff properties or environmental conditions.
2Measurement precision
If reflected light detection is used to control toasting, then the degree of browning can be controlled, but different initial reflected light values require different look-up tables for accurate control
Solution Approach 1:
The patent measures the initial reflected light intensity as a parameter and uses this value to dynamically adjust the termination threshold. Instead of requiring separate look-up tables for different bread types, the system calculates the termination threshold as a percentage reduction from the measured initial value, adapting to any foodstuff regardless of its initial color or reflective properties.
Solution Approach 2:
The patent creates a universal control method that works for all types of foodstuff. By expressing the termination condition as a percentage reduction from the initial reflected light intensity rather than using fixed absolute values or separate look-up tables, the system achieves accurate browning control for white bread, brown bread, and other foodstuffs with a single unified algorithm.
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 solution provides improved control over the browning process, ensuring consistent results by maintaining a constant illumination level and terminating the toasting operation when the desired intensity is reached, independent of initial conditions, thus addressing the inconsistency issues in conventional appliances.
Implementation Method 1
an optical system for illuminating optically the foodstuff and for detecting light reflected from the foodstuff
Implementation Method 2
a source of radiant heat in the form of a plurality of electric heating elements
Implementation Method 3
a source of radiant heat
Data Source
AI summary
A toasting appliance includes a toasting chamber, a heating element arranged to heat a foodstuff located within the toasting chamber, and an optical system for optically illuminating the foodstuff and detecting light reflected from the foodstuff. Before the foodstuff begins to change color as a result due to the heating thereof by the heating element, a controller varies the illumination of the foodstuff by the optical system so that the intensity of the light reflected from the foodstuff is at or around a set value. The controller subsequently terminates the toasting operation when the intensity of the light reflected from the foodstuff has reduced, due to toasting thereof, from the set value by an amount depending on a desired degree of toasting of the foodstuff.