Gradient Sensor Positional Accuracy During Tapping Splatter
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Solution Overview
Problem
Gradient sensors face accuracy issues during the 'tapping splatter' effect, particularly when a finger or object is landed or removed, leading to undesirable positional coordinate reporting.
Innovation Solution
A processing system with a transmitter module, receiver module, and determination module that transmits voltage variations in different excitation modes across a sensing frame period, computing changes in capacitive coupling to determine positional information, thereby improving accuracy by interleaving excitation modes and using partial clusters to reduce tapping splatter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gradient sensors use voltage variation across electrodes to determine positional information, then the sensor can detect input objects, but the accuracy of reported coordinates deteriorates during landing and removal of the finger
Solution Approach 1:
The patent applies periodic action by alternating between first and second excitation modes during different time intervals within a sensing frame period. The transmitter electrode switches between generating a first voltage variation and a second voltage variation in a periodic manner, allowing the system to capture capacitive coupling changes from multiple perspectives and eliminate tapping splatter effects.
Solution Approach 2:
The patent segments the sensing frame period into multiple time intervals, with each interval dedicated to a specific excitation mode. This segmentation allows the system to process capacitive coupling measurements from different excitation states separately, improving the accuracy of positional information by avoiding the mixing of signals from different modes.
2Measurement precision
If the transmitter electrode generates voltage variations to create capacitive coupling signals, then positional information can be determined, but tapping splatter occurs during finger landing and removal
Solution Approach 1:
The patent converts the harmful tapping splatter effect into a beneficial measurement opportunity. By capturing capacitive coupling signals during both the approach and removal phases of finger contact using different excitation modes, the system can identify and filter out spurious tapping signals while utilizing the same physical interaction that causes the problem.
Solution Approach 2:
The patent implements feedback by measuring capacitive coupling changes during multiple excitation modes and using this information to determine positional accuracy. The system continuously monitors the capacitive coupling signals and adjusts its interpretation of positional information based on the measured changes, eliminating the harmful tapping splatter effect through feedback-based validation.
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 solution significantly enhances the accuracy of reported positional information during landing and finger removal by reducing the 'tapping splatter' effect, improving the usability of capacitive sensor devices.
Implementation Method 1
compute a first measurement of a change in capacitive coupling between the transmitter electrode and the receiver electrode based on the first resulting signal
Data Source
AI summary
A processing system includes a transmitter module, a receiver module, and a determination module. The transmitter module is configured to transmit in accordance with a first excitation mode with a transmitter electrode during a first interval and a third interval of a sensing frame period, wherein, during the first excitation mode, a first voltage variation is generated in the transmitter electrode. The transmitter module is further configured to transmit in accordance with a second excitation mode with the transmitter electrode during a second interval of the sensing frame, wherein, during the second excitation mode, a second voltage variation different from the first voltage variation is generated in the transmitter electrode. The receiver module is configured to receive a first resulting signal with a receiver electrode during the first interval, receive a second resulting signal with the receiver electrode during the second interval, and receive a third resulting signal with the receiver electrode during the third interval. The determination module is configured to compute a first measurement of a change in capacitive coupling between the transmitter electrode and the receiver electrode based on the first resulting signal, compute a second measurement of a change in capacitive coupling between the transmitter electrode and the receiver electrode based on the second resulting signal, compute a third measurement of a change in capacitive coupling between the transmitter electrode and the receiver electrode based on the third resulting signal, and combine the first and third measurements. The determination module is further configured to determine positional information for an input object based on the second measurement and a combination of the first and third measurements.