Capacitive Touch Switch With Sputter Electrode for Stable Detection
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Solution Overview
Problem
Conventional touch switches face challenges in accurately detecting finger approach or contact due to small electric capacitance changes, especially with thick base resin layers and environmental interference, leading to reduced sensitivity and complex, expensive designs.
Innovation Solution
A touch switch with a conductive layer formed by sputtering, vaporization, or plating on an insulating base resin layer, allowing for a large electric capacitance change detection without compromising visual design, and reducing malfunction in switching operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a thick base resin layer is used, then the visual design freedom is improved, but the electric capacitance change becomes small leading to reduced detection sensitivity
Solution Approach 1:
The invention transitions from indirect capacitance detection through the base resin layer to direct detection by placing a conductive layer on the front surface. This dimensional change in detection approach allows the base resin layer to be thick for design freedom while maintaining high detection sensitivity through the surface-level conductive layer.
Solution Approach 2:
The conductive layer acts as an intermediary element on the front surface that mediates between the user's finger and the detection circuit. This intermediary enables direct capacitance detection without requiring the signal to pass through the thick base resin layer, thus preserving both design freedom and detection sensitivity.
2Measurement precision
If the metallic layer is exposed on the switch surface, then the electric capacitance change becomes large improving detection sensitivity, but the visual design freedom is restricted
Solution Approach 1:
The invention changes the parameter of conductive layer placement from embedded within the base resin to positioned on the front surface. This parameter change allows the conductive layer to be visually integrated into the switch design rather than exposed as a separate metallic element, thereby maintaining detection sensitivity while freeing visual design constraints.
3Adaptability or versatility
If indirect detection through base resin layer is used, then the visual design is flexible, but the switch sensitivity deteriorates when distance is large
Solution Approach 1:
The invention segments the detection function from the base resin layer structure by placing a dedicated conductive layer on the front surface. This segmentation allows the base resin layer to fulfill its structural and design roles while the conductive layer专门 handles detection, ensuring high sensitivity independent of base resin thickness.
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
The solution enables reliable detection of finger proximity with improved visual design freedom, providing a metallic glossy or resin-like appearance and reducing operational malfunctions, while maintaining sensitivity and design flexibility.
Implementation Method 1
an electric capacitance detection circuit electrically connected to the conductive layer to detect an electric capacitance change caused when a human body approaches or contacts the conductive layer
Implementation Method 2
the conductive layer is a layer formed by sputtering, vaporization, plating, or metallic painting
Implementation Method 3
the conductive layer is a layer formed by sputtering, vaporization, plating, or metallic painting
Data Source
AI summary
An electric capacitance-type touch switch, capable of reducing malfunction in switching operations and improving the degree of freedom in the visual design of switch, includes a detection circuit that can detect an electric capacitance change occurring when a human body approaches or contacts to an electrode. A sputter layer (i.e., a metallic thin film formed by sputtering) is provided on a surface of an upper lens (i.e., insulating base resin layer). The sputter layer can provide a beautiful metallic glossy appearance similar to a mirror surface. The sputter layer can be used as a panel surface providing a glossy appearance with iridescent or dichromatic effects obtainable from the hue of the base resin layer transmitted via the metallic layer. Furthermore, the sputter layer can be used as an electric capacitance detection electrode.