Touch Keyboard Layout With Under-Plate Capacitive Sensing
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Solution Overview
Problem
The presence of through holes in the capacitive circuit board of existing key-based touch keyboards increases touch dead zones, negatively impacting touch accuracy and overall performance.
Innovation Solution
A touch keyboard design that incorporates a support plate with elastomers, keycaps, linkage members, and a capacitive touchpad, where the capacitive touchpad is positioned beneath the support plate, eliminating the need for through holes and enhancing touch accuracy by minimizing dead zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If through holes are installed in the capacitive circuit board to support the key structure, then the key-based touch keyboard can be assembled, but touch dead zones increase and touch accuracy deteriorates
Solution Approach 1:
The patent relocates the capacitive touchpad from the front surface to the bottom surface of the support plate, changing the spatial dimension of the touch sensing area. This dimensional repositioning allows the touchpad to operate in a region free from key structure interference, eliminating dead zones while maintaining manufacturing feasibility through the support plate's structural design
2Measurement precision
If the capacitive touchpad is placed beneath the support plate, then touch accuracy is enhanced by minimizing dead zones, but the structural complexity increases
Solution Approach 1:
The support plate is designed to serve multiple functions simultaneously: it provides mechanical support for the key structure, houses the capacitive touchpad on its bottom surface, and incorporates through holes for elastomer insertion. This multi-functionality integrates what would otherwise be separate components, reducing overall structural complexity while maintaining high touch accuracy
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 design reduces touch dead zones and improves touch accuracy by allowing for more precise detection of keypresses and movements, providing enhanced tactile feedback and sensing capabilities.
Implementation Method 1
When the keycaps are pressed, the elastomers accumulate elastic restoring force. Once the pressure applied to the keycaps is released, the elastic restoring force from the elastomers causes the keycaps to return to their original position.
Data Source
AI summary
A touch keyboard includes a support plate, multiple elastomers, multiple keycaps, multiple linkage members, and a capacitive touchpad. The elastomers are disposed on the support plate in a manner protrudes from the top surface of the support plate. The keycaps are mounted on the top ends of the elastomers. The linkage members are positioned between the support plate and the keycaps. The capacitive touchpad is attached to the bottom surface of the support plate for sensing a location and movement trajectory of a conductive object (such as a finger) approaching the keycaps. Thus, the touch keyboard of the present invention places the capacitive touchpad beneath the support plate, which reduces or even eliminates the need for through holes in the capacitive touchpad, thereby minimizing touch dead zones and enhancing touch accuracy.