Pen State Detection Circuit for Touch-Sensor Edge Accuracy
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Solution Overview
Problem
Existing pen state detection systems produce unexpected calculation results when the electrodes of an electronic pen are positioned at the periphery or bend of a touch sensor, leading to inaccuracies in estimating the pen's position and inclination.
Innovation Solution
A pen state detection circuit that includes a processor and memory, which acquires and calculates coordinate values from a touch sensor's electrodes, applying special calculation rules when the electrodes are near the sensor's periphery or bend to correct the inclination values and smooth the output, ensuring accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the two electrodes are disposed at a physical distance from each other to enable pen detection, then the pen state can be detected, but unexpected calculation results are obtained at the periphery or bend of the touch sensor
Solution Approach 1:
The patent applies different calculation methods based on the spatial location of the electrodes. When electrodes are detected at peripheral or bend regions of the touch sensor, special calculation rules are applied to account for the distorted electric field distribution in those areas. This local differentiation resolves the contradiction by adapting the measurement approach to the specific local conditions, thereby maintaining both detection reliability and measurement precision.
Solution Approach 2:
The patent changes the calculation parameters and methods based on the detected electrode positions. When electrodes are located at the periphery or bend, the system switches from standard calculation rules to special calculation rules that adjust for the non-uniform electric field distribution. This parameter change allows the system to maintain accurate measurements across different regions of the touch sensor.
2Productivity
If ordinary calculation rules are used for inclination calculation, then the calculation is simple and fast, but unexpected results are obtained when electrodes are at periphery or bend
Solution Approach 1:
The system performs preliminary detection of electrode positions and classifies them into different regions (central area vs. peripheral/bend areas) before performing the inclination calculation. This preliminary action allows the system to pre-determine which calculation method to apply, avoiding the need to always use complex calculations while ensuring accuracy is maintained when needed.
Solution Approach 2:
The patent implements a dynamic calculation approach where the system switches between ordinary and special calculation rules based on the real-time detected electrode positions. This dynamic adaptation allows the system to maintain high calculation speed for most cases while ensuring accuracy for edge cases at the periphery or bend, thus resolving the contradiction between productivity and reliability.
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 system prevents unexpected results by correcting inclination values near the sensor's edges and bends, providing smoother and more accurate time-series inclination values during pen movement.
Implementation Method 1
a touch sensor of a capacitance type... including a plurality of sensor electrodes disposed in a planar manner
Data Source
AI summary
A pen state detection circuit that is connected to a touch sensor of a capacitance type and adapted to detect a state of an electronic pen in accordance with an output signal from the touch sensor. The touch sensor includes sensor electrodes disposed in a planar manner, and the electronic pen includes a first electrode and a second electrode. The pen state detection circuit includes a processor configured to sequentially and repeatedly: acquire first and second coordinate values in a sensor coordinate system, the coordinate system being defined on a detection surface of the touch sensor, the first coordinate values indicating a projected position of the first electrode, the second coordinate values indicating a projected position of the second electrode; calculate an inclination value indicative of an inclination of the electronic pen from the acquired first and second coordinate values in accordance with calculation rules; and output the inclination value.