Flared Capacitive Touch Sensor for Larger Sensitive Area
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Solution Overview
Problem
Existing capacitive sensors for touch control panels often require separate conductive elements or printed circuit boards, which can complicate design and increase costs, while also limiting the sensitive area and capacitive coupling with objects like a user's finger.
Innovation Solution
A capacitive sensor with a flared portion that deforms to provide an extended contact area when pressed against a panel, using a resilient spring or flexible leaves to enhance capacitive coupling without the need for additional electrodes or separate boards, allowing for a compact and cost-effective design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a separate printed circuit board or conductive foil is used to form the sensor element, then the capacitive sensor can be manufactured with conventional techniques, but the device complexity and production costs increase
Solution Approach 1:
The sensor element is integrated directly into the touch panel structure, merging the functions of the touch panel and the capacitive sensor. This eliminates the need for separate printed circuit boards or conductive foils, reducing device complexity while maintaining ease of manufacture through conventional touch panel fabrication processes
Solution Approach 2:
The touch panel serves dual functions: as the user interface panel and as the substrate for the capacitive sensor element. The conductive layer in the touch panel simultaneously provides both the touch-sensitive conductive surface and the sensor electrode, eliminating redundant components
2Volume of moving object
If a compact sensor element design is used, then the device size is reduced, but the sensitive area and capacitive coupling with objects are limited
Solution Approach 1:
The sensor element utilizes the third dimension (depth/thickness) by employing a vertically extended conductive structure within the touch panel. This allows the sensor to achieve a larger effective sensitive area through vertical stacking or extended conductive paths in the Z-direction, rather than expanding the horizontal footprint
3Reliability
If conventional contact parts like helical springs or conductive rubber pillars are used to connect the measurement circuit, then electrical connection is achieved, but the device complexity and production costs increase
Solution Approach 1:
The conductive layer that forms the sensor element is directly integrated with the measurement circuit through the touch panel's existing conductive network. This eliminates the need for separate contact parts like helical springs or conductive rubber pillars, as the electrical connection is established through the panel's inherent conductive structure
Solution Approach 2:
The unnecessary intermediate connection components (helical springs, conductive rubber pillars) are completely removed from the system. The measurement circuit is directly coupled to the sensor element through the touch panel's conductive layer, simplifying both the device structure and assembly process
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 flared portion of the sensor element increases the sensitive area and capacitive coupling, providing reliable and efficient detection of objects while maintaining a compact and affordable manufacturing process.
Implementation Method 1
the sensor element includes a flared portion which deforms when pressed against the panel so as to provide an extended contact area between the sensor element and the panel
Implementation Method 2
a measurement circuit for determining the capacitance of the sensor element. The capacitance of the sensor element is modified by the presence of a user's finger positioned adjacent the panel above the sensitive area
Data Source
AI summary
A capacitive sensor for detecting the presence of an object adjacent a panel is described. The sensor comprises an electrically conducting sensor element coupled to a capacitance measurement circuit. In use, the capacitive sensor is mounted with the sensor element adjacent an underside of the panel. The sensor element includes a flared portion which deforms when pressed against the panel to provide an extended contact area between the sensor element and the panel. When a user touches an upper side of the panel above the extended contact area, the capacitance of the sensor element is modified. This is detected by the measurement circuit and identifies a touch.