Capacitive Cooktop Control Assembly With Elastomer PCB Contact
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Solution Overview
Problem
Existing operating devices with capacitive touch switches face challenges in precise and cost-effective assembly, particularly in attaching elastic, electrically conductive plastic to printed circuit boards, leading to difficulties in making reliable electrical connections.
Innovation Solution
The design incorporates a housing with electrically conductive plastic that forms a capacitive sensor element and has fastening means for secure attachment to a component carrier, featuring an elastomer contacting material that presses onto a contact pad on the carrier, ensuring a reliable electrical connection and allowing for automated assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If elastic, electrically conductive plastic is attached to a printed circuit board to form a capacitive sensor element, then the sensor element can be integrated into the operating device, but precise positioning and reliable electrical connection are difficult to achieve
Solution Approach 1:
The device is divided into separate functional modules: the housing with integrated sensor element, the component carrier with contact fields, and the elastic contact material. This segmentation allows each module to be manufactured and positioned independently, then assembled together, achieving both precision and ease of manufacture.
Solution Approach 2:
Elastic, electrically conductive contact material serves as an intermediary between the housing and the component carrier. This intermediary element provides both mechanical connection and electrical connection, eliminating the need for precise direct attachment of the sensor element to the circuit board.
2Reliability
If retaining feet made of electrically conductive material are inserted into openings in a printed circuit board to establish electrical contact, then electrical connection is achieved, but the assembly process becomes complex and time-consuming
Solution Approach 1:
Multiple functions are merged into single elements: the housing serves as both structural support and sensor element housing; the elastic contact material provides both mechanical attachment and electrical connection. This merging reduces the number of assembly steps and increases productivity while maintaining reliability.
Solution Approach 2:
The elastic, electrically conductive contact material performs multiple functions simultaneously: it acts as a mechanical fastener, an electrical conductor, and a compensating element for positioning tolerances. This multi-functionality eliminates the need for separate retaining feet and contact elements.
3Productivity
If the sensor element assembly is designed to allow automated assembly, then productivity increases, but the design complexity may increase
Solution Approach 1:
The sensor element, housing, and contact material are pre-assembled into a complete sensor unit before integration into the operating device. This preliminary assembly simplifies the final assembly step, making it suitable for automated processes while reducing overall design complexity through modularization.
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 enables rapid, automated assembly of operating devices with capacitive touch switches, improving precision and reducing costs, while maintaining stable electrical connections even with slight movements.
Implementation Method 1
The housing (22) has electrically conductive and elastic contact material (35a, 35b) on its lower area or underside
Implementation Method 2
The capacitive sensor element can be detected and evaluated in a known manner
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A control device (14) for an electric cooking appliance (16) comprises a sensor element assembly and a planar component carrier (37) for mounting the sensor element assembly. A housing has a capacitive sensor element on its upper surface, from which an electrical contact extends to electrically conductive elastic contacting material on its lower surface (35a, 35b). Below this, a contact field (42a, 42b) is provided on the component carrier with a central through-hole (40a, 40b), wherein the electrically conductive material of the contact field extends into the through-hole and the electrically conductive elastic contacting material is pressed into the through-hole.