Force Touch Interface Calibration Matrix for Torsion Error Correction
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Solution Overview
Problem
Force-based touch pads face inaccuracies in measuring force magnitude and touch position due to manufacturing errors, such as sensor misalignment and torsion, which degrade recognition accuracy.
Innovation Solution
A force-based touch interface device with a torsion preventing structure and multiple sensors measures force data, estimates symmetrical points, and generates a calibration matrix to correct manufacturing errors, improving measurement accuracy by comparing measured and ideal force data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the touch pad is made flexible to enable force touch sensing, then force magnitude measurement is enabled, but manufacturing errors and torsion occur causing measurement inaccuracy
Solution Approach 1:
The patent applies preliminary calibration action by pre-determining correction values for manufacturing errors. During manufacturing, the actual positions of sensors are measured and correction values are calculated in advance. These correction values are stored and applied during operation to compensate for the fixed manufacturing errors, thereby improving measurement accuracy without requiring perfect manufacturing precision.
2Ease of manufacture
If the touch pad structure is simplified to reduce cost, then manufacturing ease is improved, but torsion prevention capability is reduced leading to measurement errors
Solution Approach 1:
The patent replaces the mechanical torsion prevention approach with a computational correction approach. Instead of relying on complex mechanical structures to prevent torsion, the system uses software-based correction values that compensate for torsion-induced measurement errors. This substitution maintains manufacturing simplicity while improving measurement reliability through mathematical correction rather than mechanical constraint.
3Measurement precision
If multiple sensors are added to improve measurement accuracy, then force magnitude measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent changes the parameter approach by introducing correction values as a new parameter set. Rather than adding more sensors to improve precision, the system maintains the existing sensor count but adds correction parameters that adjust the measurement readings. This parameter change allows the system to achieve higher measurement precision without increasing the physical complexity of the sensor array.
Data Source
AI summary
A force based touch interface device comprising a touch substrate, a torsion preventing structure for preventing torsion of the touch substrate by an externally-applied force touch, a plurality of sensors for measuring the force touch applied to the touch substrate at different positions, an input device for applying the force touch onto the touch substrate, and a controller for measuring force data using the plurality of sensors when the force touch is applied onto the touch substrate, for estimating force data for symmetrical points for touch points to which the force touch is applied using the measured force data, and for comparing the measured force data and the estimated force data with ideal force data to generate a calibration matrix for correcting a process error.