Capacitive Sensor Key Assembly Without Soldered PCB Contacts
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Solution Overview
Problem
Existing capacitive sensor button designs for household appliances are costly and complex to assemble, requiring soldering or welding of sensor elements to printed circuit boards, which increases manufacturing costs and complicates the assembly process.
Innovation Solution
A capacitive sensor button design featuring a one-piece electrically conductive sensor element with a sensor surface that rests against the rear of an insulating cover plate, where the sensor element is fixed using a light box to maintain position and establish electrical contact with the printed circuit board without soldering or welding, utilizing a resilient contact element for secure and easy connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensor elements are soldered or welded to printed circuit boards, then reliable electrical connections are achieved, but manufacturing costs increase and assembly complexity increases
Solution Approach 1:
The patent replaces the mechanical joining processes of soldering or welding with a simple mechanical insertion system. The sensor element is designed as a plug-in component that can be directly inserted into corresponding receptacles on the printed circuit board, eliminating the need for thermal processing and complex assembly equipment while maintaining reliable electrical contact through spring-loaded contact elements.
2Reliability
If sensor elements are soldered or welded to printed circuit boards, then secure electrical connections are achieved, but manufacturing costs increase
Solution Approach 1:
The sensor element is designed as an inexpensive, replaceable plug-in component rather than a permanently attached element. The use of simple spring contacts and standardized receptacles allows for cost-effective manufacturing and easy replacement if needed, significantly reducing the overall manufacturing cost compared to soldering or welding processes that require expensive equipment and skilled labor.
3Stability of the object's composition
If sensor elements are fixed with rigid plug-in or supporting legs, then stable positioning is achieved, but device complexity increases
Solution Approach 1:
The patent employs dynamic spring-loaded contact elements instead of rigid supporting legs. These spring contacts can elastically deform to accommodate minor position variations and assembly tolerances, providing stable positioning without requiring complex rigid support structures. The spring mechanism automatically adjusts to maintain optimal contact pressure and positioning.
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 design simplifies and cost-reduces the assembly of capacitive sensor buttons by eliminating the need for soldering or welding, ensuring secure and reliable electrical connections while reducing manufacturing costs and assembly complexity.
Implementation Method 1
The sensor surface forms one plate of an open capacitor, the capacitance of which depends on the distance to a second plate (e.g. earth), which is changed, for example, by the proximity of a user's finger.
Data Source
Figure 1~2
Figure 3
Figure 4A~4D
AI summary
The invention relates to a control device for a household appliance comprising at least one capacitive sensor key. Said sensor key comprises an electrically conductive sensor element (2) provided with a sensor surface (2''), said sensor element being arranged on the under side of an electrically insulating cover plate (3) of the control device (1). A printed circuit board (5) is arranged at a distance from the cover plate (3) and the sensor element (2) extends from the cover plate (3) to the printed circuit board (5). A light box (7) is disposed between the cover plate (3) and the printed circuit board (5) and the sensor element (2) is fixed in a predetermined position on the under side of the cover plate (3) parallel and perpendicular to the cover plate (3) due to said light box.