Pen State Detection Circuit Using 2D Signal Synthesis
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Solution Overview
Problem
Existing writing input systems using electronic pens face challenges in accurately detecting the position and posture of the pen due to variations in electrode geometry and user interaction, leading to inconsistent estimation accuracy.
Innovation Solution
A pen state detection circuit that acquires one-dimensional signal distributions from a touch sensor with multiple electrodes, synthesizes these into two-dimensional signal or feature distributions, and uses a machine learning model, such as a convolutional neural network, to estimate the pen's position and posture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two electrodes are physically separated in the electronic pen, then the pen can detect position even when the hand is not in contact with the detection surface, but the estimation accuracy varies depending on the three-dimensional shape of the electrodes and the position/posture of the pen
Solution Approach 1:
The patent transitions from analyzing single-direction (one-dimensional) signal distributions to two-dimensional signal distributions by combining signals from multiple electrode pairs in different directions. This dimensional expansion allows the system to capture comprehensive spatial information about the pen's position and posture, resolving the accuracy variations caused by different electrode configurations and pen orientations.
Solution Approach 2:
The patent merges signal distributions from multiple electrode pairs into a unified two-dimensional signal distribution map. By combining the one-dimensional signal distributions obtained from different electrode pairs, the system creates a comprehensive representation of the pen's capacitive signature, enabling accurate position and posture estimation regardless of the specific electrode geometry or pen orientation.
2Device complexity
If one-dimensional signal distributions are processed separately, then the processing steps are simple, but the estimation accuracy of pen state is insufficient
Solution Approach 1:
The patent enhances the analysis from one-dimensional to two-dimensional by synthesizing signal distributions across multiple directions. This creates a richer feature space that captures the spatial relationships between different electrode pairs, enabling accurate extraction of both position and posture information while maintaining a systematic processing approach.
Solution Approach 2:
The patent performs preliminary synthesis of one-dimensional signal distributions into a two-dimensional signal distribution map before extracting features and estimating pen state. This preliminary organization of data into a coherent two-dimensional representation simplifies subsequent feature extraction and improves the accuracy of position and posture estimation.
3Device complexity
If the electronic pen uses fixed electrode configuration, then the device structure is simple, but the estimation accuracy changes according to the three-dimensional shape of electrodes and pen posture
Solution Approach 1:
The patent introduces dynamic analysis by examining how the two-dimensional signal distribution changes with different pen postures and electrode configurations. Instead of relying on fixed geometric relationships, the system adaptively extracts features from the signal distribution that remain consistent across various pen orientations, ensuring reliable estimation regardless of the actual three-dimensional electrode arrangement or pen angle.
Solution Approach 2:
The patent changes the approach from using fixed geometric parameters of electrodes to using dynamic signal distribution characteristics. By analyzing the two-dimensional signal distribution and its features rather than relying on predetermined electrode geometries, the system maintains consistent estimation accuracy across different electrode configurations and pen postures.
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
This approach significantly improves the estimation accuracy of the pen's state by leveraging synthesized two-dimensional data, reducing data handling complexity and enhancing processing speed while maintaining high accuracy in detecting pen position and posture.
Implementation Method 1
each of the first signal distribution and the second signal distribution being a one-dimensional signal distribution indicating a change in capacitance with approach of the electrode
Data Source
AI summary
Provided is a pen state detection circuit for detecting a state of an electronic pen based on a signal distribution detected by a touch sensor including a plurality of sensor electrodes arranged in a plane shape, the electronic pen including at least one electrode, the pen state detection circuit, in operation, acquires, from the touch sensor, a first signal distribution and a second signal distribution, generates a two-dimensional signal distribution by synthesizing the first signal distribution and second signal distribution, or generates a two-dimensional feature distribution by synthesizing a first feature distribution relating to a shape of the first signal distribution and a second feature distribution relating to a shape of the second signal distribution, and estimate a position indicated by the electronic pen or a posture of the electronic pen from the two-dimensional signal distribution or two-dimensional feature distribution.