Touch Interface Force Sensor Layout for Uniform Capacitance Response
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Solution Overview
Problem
Existing touch sensors struggle with non-uniform changes in electrical values across force sensors when a target force is applied, leading to inaccuracies in detecting and interpreting force magnitudes on touch surfaces.
Innovation Solution
A system with distinct electrode configurations and gap heights for capacitive force sensors, including a first sensor at the center and a second sensor at the edge, which yield uniform changes in capacitance values responsive to a target force, allowing for accurate detection and interpretation of force magnitudes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform electrode configurations are used across all force sensors, then manufacturing is simplified, but measurement precision deteriorates due to non-uniform capacitance changes at different positions
Solution Approach 1:
The patent implements different electrode configurations at different positions on the touch surface. Center force sensors use a first electrode configuration while edge force sensors use a second electrode configuration. This local differentiation ensures that each sensor produces uniform capacitance changes for its specific position, thereby achieving accurate force magnitude detection across the entire touch surface without compromising manufacturing feasibility.
2Device complexity
If single gap height is used for all capacitive force sensors, then device complexity is reduced, but measurement precision worsens due to position-dependent sensitivity variations
Solution Approach 1:
The patent specifies different gap heights between the electrode layer and counter electrode layer for center versus edge force sensors. Center force sensors utilize a first gap height while edge force sensors utilize a second gap height. This local optimization compensates for position-dependent sensitivity variations, ensuring uniform capacitance changes and accurate force detection across different locations on the touch surface.
3Ease of operation
If standard touch sensor design is used, then ease of operation is maintained, but measurement precision deteriorates due to non-uniform force detection across the surface
Solution Approach 1:
The patent implements position-specific electrode and gap configurations that are transparent to the user. The different electrode configurations and gap heights for center and edge sensors are automatically compensated by the control circuit, which interprets capacitance changes using position-appropriate reference values. This maintains uniform force detection accuracy across the entire touch surface without requiring any changes in user interaction or additional operational complexity.
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 system achieves uniform changes in capacitance values across sensors, enabling precise detection and interpretation of force inputs, enhancing accuracy and reducing sensitivity to noise.
Implementation Method 1
A system with distinct electrode configurations and gap heights for capacitive force sensors, including a first sensor at the center and a second sensor at the edge, which yield uniform changes in capacitance values responsive to a target force
Data Source
AI summary
A system includes: a substrate including an edge supported by a chassis; a first electrode spanning a first area of the substrate and arranged proximal a center of the substrate; and a second electrode spanning a second area, greater than the first area, on the substrate and interposed between the first electrode and the edge of the substrate. The system further includes a first coupling region: facing the first electrode; and electrically coupling to the first electrode to yield a first electrical value at the first electrode responsive to application of a first force magnitude proximal the center of the substrate. The system also includes a second coupling region: facing the second electrode; and electrically coupling to the second electrode to yield a second electrical value, approximating the first electrical value, at the second electrode responsive to application of the first force magnitude proximal the center of the substrate.