Electrostatic Coordinate Input Device Noise Reduction
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Solution Overview
Problem
Conventional touch panel systems face precision issues in determining touch positions due to noise affecting the touch position, moving speed, and moving acceleration used to set predicted coordinates or ranges.
Innovation Solution
An electrostatic coordinate input device is designed with a plurality of sensor electrodes on the rear surface of a manipulation surface, a measuring circuit to detect capacitance between the electrodes and an indicating body, and a calculating unit that executes first and second calculation processes to accurately calculate the coordinate of the indicating body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional touch position detecting methods are used to determine touch positions based on touch manipulation history, then the system can provide predictive touch position coordinates, but noise affects the precision of touch position, moving speed, and moving acceleration measurements
Solution Approach 1:
The system performs preliminary calculations of predicted touch positions, moving speeds, and moving accelerations based on historical touch data before the actual touch occurs. This allows the system to have pre-computed reference values ready for comparison with actual measurements, reducing the impact of noise on final position determination
Solution Approach 2:
The system continuously compares actual touch position measurements with predicted touch positions and uses the difference (error) to refine future predictions. This feedback mechanism allows the system to adapt to noise patterns and improve measurement precision over time by learning from deviations caused by noise
2Loss of time
If the system uses touch position, moving speed, and moving acceleration to set predicted coordinates, then it can improve response time, but noise reduces the precision of these parameters
Solution Approach 1:
The system pre-calculates predicted touch positions, moving speeds, and moving accelerations based on historical data before actual touch events occur. This preliminary computation enables rapid response to touch events without requiring complex real-time calculations, thus reducing response time while maintaining precision through pre-processed accurate data
Solution Approach 2:
The system dynamically adjusts the weight given to different parameters (touch position, moving speed, moving acceleration) when calculating predicted coordinates. By optimizing the contribution of each parameter based on current conditions and noise levels, the system achieves both fast response time and high precision in coordinate prediction
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 device achieves high precision in calculating the coordinate of the indicating body by reducing noise effects through averaging and predicted coordinate calculations, thereby enhancing the accuracy of touch position determination.
Implementation Method 1
a measuring circuit that measures a capacitance between each of the plurality of sensor electrodes and an indicating body
Data Source
AI summary
An electrostatic coordinate input device includes: a plurality of sensor electrodes disposed on the rear surface side of a manipulation surface; a measuring circuit that measures a capacitance between each of the plurality of sensor electrodes and an indicating body, with which a manipulation input is performed; and a calculating unit that calculates the coordinate of the indicating body according to a plurality of capacitances measured by the measuring circuit. The calculating unit repeatedly executes first calculation processing, in which the calculating unit measures the coordinate of the indicating body from the plurality of capacitances and then calculates an average moving speed of the indicating body according to the measured coordinate of the indicating body, as well as second calculation processing. In the second calculation processing, an average is calculated between a predicted coordinate and the measured coordinate of the indicating body, as the coordinate of the indicating body.