Ground Trace Electrode Touch Force Signal Separation
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Solution Overview
Problem
Existing force/touch input devices face limitations due to complex geometric and electrical configurations of transmitter and receiver electrodes in multiple layers, leading to inaccurate object localization and reduced usability, as they struggle to distinguish between touch and deflection signals.
Innovation Solution
The strategic arrangement of transmitter and receiver electrodes in a single or two layers, with a ground trace electrode between them, allows for the separation of touch and deflection signals, enabling the derivation of pure touch and deflection signals independently, thereby improving user interface functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If transmitter and receiver electrodes are arranged in multiple layers, then force sensing capability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent segments the electrode functions by introducing a ground trace electrode that is selectively connected to ground or left floating. This segmentation allows the same physical electrode structure to serve different functional purposes (grounding vs. force sensing) at different times, eliminating the need for complex multi-layer electrode arrangements while maintaining force sensing capability
Solution Approach 2:
The ground trace electrode's electrical connection state is dynamically changed between grounded and floating states based on operational requirements. When grounded, it provides electromagnetic shielding; when floating, it enables force sensing. This dynamic reconfiguration allows a simple single-layer electrode structure to achieve complex force sensing functionality
2Measurement precision
If transmitter and receiver electrodes are arranged in multiple layers, then force sensing capability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent segments the grounding function from the sensing function by using a ground trace electrode that can be selectively connected. This allows the electrode layers to be manufactured with standard precision without requiring complex multi-layer alignment, as the grounding trace is simply routed on the same layer or adjacent layer without precise overlay requirements
3Measurement precision
If ground trace electrode is selectively grounded, then deflection signal separation is improved, but signal processing complexity increases
Solution Approach 1:
The system employs periodic toggling of the ground trace electrode between grounded and floating states during signal acquisition. This periodic switching creates distinct signal phases that can be easily separated through simple synchronous detection or subtraction operations, avoiding complex continuous signal processing while achieving effective deflection signal separation
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 configuration enhances the accuracy of positional and force information detection, improving the usability and flexibility of input devices by isolating deflection effects from touch signals, resulting in improved user interface functionality.
Implementation Method 1
the processing system is configured to selectively toggle a ground trace electrode between a first and second state. In the first state, the ground trace electrode functions as a ground electrode. In the second state, the ground trace electrode functions as a force receiver electrode
Data Source
AI summary
Methods, systems and devices are described for operating an electronic system which includes a first plurality of sensor electrodes disposed in a first layer and configured to detect input objects at an input surface of the input device, the first plurality of sensor electrodes including a first subset of transmitter electrodes; a second plurality of sensor electrodes configured to detect a force imparted to the input surface and configured for capacitive coupling with the first subset of transmitter electrodes; and a compressible dielectric configured to compress in response to force applied to the input surface. The capacitive coupling between the transmitter electrodes and the second plurality of sensor electrodes is configured to vary in response to the applied force.