Capacitive Matrix Electrode Array Force Sensing
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Solution Overview
Problem
Existing input devices struggle to effectively integrate force sensing without additional sensors, limiting their ability to detect forces applied outside the direct sensing region, which hampers usability and accuracy in electronic systems.
Innovation Solution
The integration of a matrix electrode array within display devices for capacitive sensing, allowing the detection of bending responses and force estimates through capacitive scans, enabling force-sensitive buttons and input actions without requiring separate force sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional force sensors are integrated into input devices, then force sensing capability is improved, but device complexity increases
Solution Approach 1:
The existing capacitive sensor array is made multi-functional by enabling it to detect both touch proximity and force applied to buttons. The same electrodes that detect touch location are also used to sense force magnitude through capacitive coupling changes, eliminating the need for separate force sensors.
Solution Approach 2:
The capacitive sensor array serves itself by using its inherent capacitive coupling to detect both touch and force. The system leverages the natural electrical properties of the existing sensor structure to provide force sensing capability without requiring additional dedicated force sensing components.
2Ease of operation
If force sensing is limited to the direct sensing region, then device complexity is reduced, but usability deteriorates
Solution Approach 1:
The input surface acts as an intermediary that transmits mechanical force from buttons located outside the direct sensing region to the capacitive sensor array. When a button is pressed, the force deforms the input surface, creating capacitive coupling changes that the sensor array can detect, thereby extending force sensing capability beyond the direct sensing region.
Solution Approach 2:
The solution extends force detection from a two-dimensional direct sensing region to a three-dimensional space by utilizing the mechanical deformation of the input surface. Force applied at any location on the input surface creates measurable capacitive changes across the sensor array, effectively adding a spatial dimension to force sensing coverage.
3Measurement precision
If capacitive scans are performed to detect bending responses, then measurement precision is improved, but use of energy increases
Solution Approach 1:
Capacitive scans are performed periodically rather than continuously, allowing the system to detect force applied to buttons while conserving energy. The periodic scanning approach balances the need for accurate force measurement with energy conservation, enabling the system to operate efficiently while maintaining measurement capability.
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 solution enhances usability by enabling the detection of forces applied elsewhere, improving accuracy and reducing false activations, as the matrix electrode array can measure spatial deformations caused by input forces, allowing for seamless integration of force-sensitive features into electronic systems.
Implementation Method 1
perform a capacitive scan using a plurality of electrodes disposed in a display device
Implementation Method 2
determine, using the capacitive scan, a bending response of an input surface covering the first area and a second area. The bending response results from an input force being applied to the input surface
Data Source
AI summary
A processing system includes a sensor module and a determination module. The sensor module is configured to perform a capacitive scan using electrodes disposed in a display device in a first area. The determination module is configured to determine, using the capacitive scan, a bending response of an input surface covering the first area and a second area. The bending response results from an input force being applied to the input surface in the second area. The determination module is further configured to determine, using the bending response, a force estimate of the input force, and determine, based on the force estimate, whether to perform an interface action.