Jitter Force Filter for Position-Based Touch Sensing
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Solution Overview
Problem
Existing position compensation techniques in force sensing input devices elevate jitter effects in force sensor data, leading to inaccurate sensing operations, especially at the edges or corners of the input surface and when dealing with moving input objects.
Innovation Solution
A jitter force filter is applied to modify force sensor data based on determined input parameters, such as position and movement, to correct for jitter effects and improve force information accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If position compensation techniques are applied to force sensor data, then force sensing accuracy is improved, but jitter effects are elevated
Solution Approach 1:
A jitter filter is introduced as an intermediary component between the position compensation module and the force sensor data output. This filter mediates the conflicting requirements by smoothing the compensated force data to eliminate jitter effects while preserving the accuracy improvements gained from position compensation. The filter acts as a buffer that reconciles the trade-off between enhancement and instability.
Solution Approach 2:
The system dynamically adjusts filtering parameters based on the input object's movement characteristics. When an input object is detected moving across the input surface, the system modifies the degree of jitter filtering applied to the force sensor data. This parameter adaptation allows the system to maintain force sensing accuracy while suppressing jitter effects that become prominent during movement.
2Measurement precision
If position compensation is applied to force sensor data, then sensing accuracy is improved, but sensing stability deteriorates
Solution Approach 1:
The jitter filter serves as a stabilizing intermediary that processes the position-compensated force data. It removes high-frequency fluctuations and jitter artifacts introduced by the compensation process, thereby restoring sensing stability while maintaining the accuracy benefits. The filter ensures that the output data remains stable even when position compensation is actively applied.
3Measurement precision
If position compensation techniques are used, then force measurement accuracy is improved, but data reliability at edges and corners deteriorates
Solution Approach 1:
The system applies position-dependent jitter filtering where the filtering strength varies based on the location of the input object on the input surface. At edges and corners where jitter effects are more pronounced, stronger filtering is applied locally. In central regions where jitter is less problematic, lighter filtering is used. This local adaptation maintains data reliability across all regions while preserving overall measurement accuracy.
Solution Approach 2:
The filtering parameters are dynamically changed based on the position of the input object. When the object is detected near edges or corners, the system increases the jitter filter strength for those specific regions. This position-based parameter adjustment ensures that data reliability is maintained at problematic locations without compromising the accuracy improvements gained from position compensation.
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 jitter force filter enhances the accuracy of force information detection by reducing mechanical and electronic noise, maintaining precise sensing operations across different areas of the input surface and during object movement.
Implementation Method 1
determine a first input parameter of an input object in contact with the sensing device based on the capacitive sensor data
Data Source
AI summary
An input device (100) is configured to detect force being applied to an input region (120) of the device (100) by an input object (140), in addition to the position of the input object (140) using touch sensing methods. The input device (100) applies a position-based jitter force filter to the force sensor data to compensate for a non-uniform response across the input device (100), as well as the movement of an input object (140).