Optical Sensor Housing Segmentation for Wash Water Protection
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Solution Overview
Problem
Optical sensors in household washing machines and dishwashers face the challenge of protecting electrical/electronic components from wash water, which can lead to interference or failure, especially when exposed to mains voltage and potential short circuits.
Innovation Solution
The light-emitting and light-receiving elements are housed in a sealed subspace within the sensor, with the measurement light path extending through a separate sealed subspace, using a light guide body with reflection surfaces and sealing elements to prevent water ingress, ensuring the electrical components remain dry and protected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the light-emitting element and light-receiving element are arranged outside the housing in the wash compartment, then the measurement light path can directly measure turbidity in the wash water, but the electrical/electronic components are exposed to wash water causing interference or failure
Solution Approach 1:
The housing interior is divided into two separate subspaces: a first subspace containing the electrical/electronic components and a second subspace containing the light-emitting and light-receiving elements. This segmentation isolates the electrical components from the wash water while allowing the optical elements to measure turbidity directly in the wash compartment, resolving the contradiction between measurement precision and component protection.
2Measurement precision
If the measurement light path extends through the wash compartment outside the housing, then turbidity measurement is enabled, but wash water may enter the housing and cause short circuits in the electrical components
Solution Approach 1:
A sealing element acts as an intermediary barrier between the first subspace (electrical components) and the second subspace (optical elements). This sealing element prevents wash water from entering the electrical component area while allowing the measurement light path to extend through the wash compartment for turbidity measurement, eliminating water ingress damage without compromising measurement capability.
3Reliability
If the first subspace is sealed from the second subspace, then electrical components are protected from wash water, but the measurement light path must be carefully designed to maintain sealing integrity
Solution Approach 1:
A flexible sealing element is used to seal the housing interior into two separate subspaces. This sealing element can be implemented as a flexible membrane or thin film that effectively isolates the electrical components from the wash water while allowing the measurement light path to pass through the housing wall. The flexible sealing element simplifies the overall structure compared to rigid sealing mechanisms while maintaining effective protection.
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 effectively prevents wash water from interfering with the sensor's electrical functions, enhancing the protection of the sensor and the machine by preventing short circuits and ensuring reliable operation.
Implementation Method 1
The at least one light guide body preferably has two reflection surfaces, which are used for total reflection of the light guided along the measurement light path
Data Source
AI summary
An optical sensor to measure the turbidity of wash water in a household washing machine or dishwasher, includes a housing having a housing interior containing a measurement module having a light-emitting element and a light-receiving element, the measurement module defining a measurement light path which extends from the light-emitting element to the light-receiving element and passes outside the housing over a part of its path length. The light-emitting element and the light-receiving element are arranged together in a first subspace of the housing interior, and the measurement light path extends over a part of its path length through at least one second subspace of the housing interior, which is sealed from the first subspace. All the electrical/electronic components of the measurement module are fitted in the first subspace, so that any ingress of wash water into the second subspace does not compromise the electrical functionality of the sensor.