Capacitive Touch Switch Assembly With Spring-Biased Sensor Contact
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Capacitive touch switches in electronic household appliances face challenges in maintaining functionality due to air gaps and temperature changes, installation, and manufacturing tolerances, particularly in water-bearing appliances where electronic protection is needed.
Innovation Solution
The operating device incorporates a capacitive sensor element with a head section outside the housing and a contact section inside, biased by a spring element to ensure contact without air gaps, allowing for tolerance compensation and protection of electronics within a housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the capacitive sensor element is made rigid and fixed directly to the circuit board, then the electronic protection is improved, but the functionality is worsened due to air gaps and tolerance accumulation
Solution Approach 1:
The sensor element is designed with a flexible contact section that can dynamically adjust its position to maintain optimal contact with the aperture. This flexible section allows the sensor element to compensate for manufacturing tolerances and installation variations while remaining enclosed in the protective housing, thus resolving the contradiction between electronic protection and contact precision.
2Reliability
If the sensor element is enclosed within the housing for protection, then the electronic protection is improved, but the functionality is worsened due to inability to compensate tolerances
Solution Approach 1:
The sensor element incorporates a flexible contact section that enables dynamic adaptation within the protective housing. This flexible section can deform and adjust to compensate for installation and manufacturing tolerances, allowing the sensor to maintain proper contact with the aperture while remaining protected inside the housing.
Solution Approach 2:
The sensor element's contact section is designed with variable physical properties (flexibility) that allow it to change its configuration in response to tolerance variations. This parameter change enables the sensor to adapt its position and maintain optimal contact conditions while enclosed in the protective housing.
3Manufacturing precision
If a compression spring is used to bias the sensor element, then the contact precision is improved, but the device complexity is worsened
Solution Approach 1:
The spring element and sensor element are merged into a single integrated component. The sensor element itself is designed with a spring-like flexible contact section that combines the functions of both the sensor and the biasing mechanism, eliminating the need for a separate compression spring and reducing overall device complexity while maintaining contact precision.
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 ensures reliable functionality of capacitive touch switches in water-bearing appliances by minimizing air gaps and accommodating installation and manufacturing tolerances, while providing protection for the electronics.
Implementation Method 1
the sensor element, and thus in particular its head section, is biased towards the aperture by the spring element
Implementation Method 2
a capacitive sensor element typically forms a capacitance with the user's finger via a dielectric aperture
Implementation Method 3
forms a capacitance with the user's finger via a dielectric aperture
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The operating device (10) has a housing made of an electrically insulating material, a printed circuit board arranged in the housing, and a sensor element partially made of an electrically conductive material. The sensor element has a head section arranged outside the housing and a contact section projecting through a through-opening in the housing. A spring element is arranged between an electrical contact surface of the circuit board and the contact section.