Optical sensor for a laundry processing appliance
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Solution Overview
Problem
Existing optical sensors in laundry processing appliances, such as washing machines, face challenges in maintaining measurement accuracy due to tilting of reflective-surface carriers in rough environments, which affects the intensity of the radiant signal detected.
Innovation Solution
The optical sensor design includes a reflective-surface carrier motionally coupled to a guide rod, with a light-emitting and light-receiving element configuration where the beam axis is parallel or coincident with the opening longitudinal axis, ensuring that tilting has a minimal effect on measurement accuracy. This configuration, combined with a helical spring for axial biasing, maintains high measurement precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the light beam is incident upon the reflective surface in an eccentrically offset manner, then the sensor can detect axial distance changes, but tilting of the reflective-surface carrier substantially affects the radiant intensity detected
Solution Approach 1:
The patent applies asymmetry by intentionally offsetting the light beam incidence from the center of the reflective surface. The light beam is directed to hit the reflective surface at a distance of 0.5 to 2 mm from the center, creating an asymmetric measurement configuration that enables axial distance detection while the specific offset position is optimized to minimize tilting effects
Solution Approach 2:
The patent changes the spatial parameters of the optical system by defining specific distances between the light beam incidence point and the center of the reflective surface (0.5 to 2 mm). This parameter optimization resolves the contradiction by finding the optimal balance between measurement sensitivity and tilting tolerance
2Measurement precision
If the light-emitting element and light-receiving element are positioned to maximize detection sensitivity, then measurement precision improves, but the sensor becomes more sensitive to environmental tilting
Solution Approach 1:
The patent optimizes the geometric parameters of the optical system, specifically the position of light incidence on the reflective surface (0.5 to 2 mm from center) and the distances between optical elements. These parameter changes achieve high measurement precision while reducing sensitivity to environmental tilting
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
The solution ensures high measurement accuracy by minimizing the impact of tilting on the radiant intensity detected, providing reliable force measurements in the dynamic environment of a washing machine.
Implementation Method 1
a light-emitting element and a light-receiving element, which are both disposed in a stationary manner relative to the sensor housing
Implementation Method 2
a reflective-surface carrier that is accommodated in the housing interior and that is motionally coupled to the guide rod and has a reflective surface
Implementation Method 3
a helical spring, by means of which the reflective-surface carrier is biased into a neutral position relative to a sensor housing
Data Source
AI summary
An optical sensor includes a sensor housing having a through-opening that connects a housing interior and that has an opening longitudinal axis, a guide rod that is guided in an axially displaceable manner in the through-opening and that projects into the housing interior, and a reflective-surface carrier that is accommodated in the housing interior and that is motionally coupled to the guide rod and has a diffusely reflecting, reflective surface. The sensor also includes a light-emitting element and a light-receiving element, which are both disposed in a stationary manner relative to the sensor housing and are at a distance from the reflective surface that is dependent on the axial position of the reflective-surface carrier.