PCB-Based Capacitive Sensing for Household Appliance User Interfaces
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Solution Overview
Problem
The high production costs and complexity of manufacturing custom metal capacitive sensing elements for household appliances, particularly in refrigerating and freezing devices, lead to increased costs and management challenges.
Innovation Solution
Designing capacitive sensing elements as printed circuit boards (PCBs) that integrate the sensing circuit, reducing the number of components and allowing the PCB to serve both as the sensing component and circuit carrier, thereby lowering production costs and simplifying manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If custom metal capacitive sensing elements are used, then the sensing element can be tailored for the appliance, but the production cost increases significantly
Solution Approach 1:
The patent merges the capacitive sensing element with the PCB by printing the sensing circuit directly on the PCB board. This integration eliminates the need for separate metal sensing elements while maintaining the capacitive sensing function, thereby reducing production costs and simplifying manufacturing.
Solution Approach 2:
The PCB serves multiple functions: it acts as both the circuit carrier and the capacitive sensing element. This multi-functionality allows the same component to fulfill both electrical connection and user interaction detection roles, reducing the total number of components and production costs.
2Adaptability or versatility
If multiple metal sheet sensing surfaces are manufactured for different models, then each model gets customized sensing elements, but the manufacturing management becomes difficult
Solution Approach 1:
The PCB is designed to serve as both the circuit board and the capacitive sensing element across different appliance models. This universal approach allows the same PCB design to be adapted for various models without requiring separate metal sensing elements for each, greatly simplifying manufacturing management.
Solution Approach 2:
The capacitive sensing properties are adjusted by changing parameters in the PCB design, such as the trace layout, copper thickness, or dielectric material properties, rather than creating entirely different metal sensing elements for each model. This allows customization while maintaining a unified manufacturing process.
3Reliability
If separate metal sensing elements are used, then the sensing function is achieved, but the number of components and installation space increases
Solution Approach 1:
The patent combines the capacitive sensing element with the PCB structure, eliminating the need for separate metal sensing elements. This integration reduces the total number of components while maintaining the sensing function, as the PCB itself becomes the sensing element through printed conductive traces.
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 approach reduces production costs, minimizes the number of components, and enhances manufacturing efficiency while providing a seamless user interface experience by eliminating edges between the display and sensing elements, thus improving user interaction.
Implementation Method 1
capacitive sensing element with a sensing surface... a capacitive sensing circuit... configured to control said household appliance and/or said display in function of (response to) a signal received from said capacitive sensing circuit after a user interaction on the capacitive sensing element
Data Source
AI summary
Household appliance (2) with a user interface (20) comprising: •—a display (64), •—a switch element (56) associated to said display (64) comprising at least one capacitive sensing element (58) with a sensing surface, •—a capacitive sensing circuit (62), •—a control unit (68) connected to said display (64) and to said capacitive sensing circuit (62), configured to control said household appliance (2) and/or said display (64) in function of a signal received from said capacitive sensing circuit (62) after a user interaction on the capacitive sensing element (58) of said switch element (56), whereby said capacitive sensing element (58) is built as a PCB (60) where the capacitive sensing circuit (62) is provided.