Pen Position Detection Using 2D Coil Signal Distribution
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Solution Overview
Problem
Conventional position detecting devices experience reduced accuracy in coordinate derivation when the position indicator is inclined in an oblique direction due to dispersed information in the X-axis and Y-axis directions.
Innovation Solution
A position detecting method and device that utilize a first sensor coil group with conducting wires arranged in a first direction and a second sensor coil group with electrodes in a second direction intersecting the first, generating an alternating magnetic field and obtaining a pen signal response to derive two-dimensional position information using a two-dimensional distribution of signal levels at intersections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate X-axis and Y-axis sensor coil groups are used to detect position, then the device can obtain coordinate information in both directions, but the accuracy of coordinate derivation deteriorates when the position indicator is inclined in an oblique direction due to dispersed information
Solution Approach 1:
The patent combines the X-axis sensor coil group and Y-axis sensor coil group into an integrated sensor system where both sets of coils work simultaneously. The signal processing unit integrates signals from both coil groups to derive coordinates, merging the detection capabilities into a unified system that maintains accuracy for both axial and oblique position indicators.
Solution Approach 2:
The patent transitions from separate one-dimensional detection along X and Y axes to two-dimensional coordinate derivation by integrating signals from both sensor coil groups. This dimensional integration allows the system to accurately determine positions in the plane, including oblique directions, by combining information from multiple detection dimensions.
2Measurement precision
If sequential scanning of sensor coils is performed to detect position, then the device can identify approximate and accurate positions, but the detection time increases due to the sequential process
Solution Approach 1:
The patent performs global scanning first to identify the approximate position of the position indicator, then uses this preliminary information to guide the sector scanning process. By performing preliminary detection to locate the general area, the system reduces the time required for accurate position determination without sacrificing measurement precision.
Solution Approach 2:
The patent divides the detection process into two sequential stages: global scanning to identify approximate position, and sector scanning to determine accurate position. This segmentation allows the system to efficiently allocate detection resources, performing comprehensive scanning only when necessary and using targeted scanning for precise measurement.
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
Improves coordinate accuracy by accurately determining the position and inclination of the position indicator even when it is inclined, enhancing the precision of coordinate derivation.
Implementation Method 1
generates an alternating magnetic field (transmission magnetic field, the same applies hereinafter) by feeding a current through each coil of the X-sensor coil group arranged on an X-axis
Implementation Method 2
The position indicator includes a resonance circuit constituted by a coil and a capacitor
Data Source
AI summary
A position detecting method in a position detector is provided. The position detector includes a first sensor coil group and a second sensor coil group. The position detecting method includes a first step of the position detector generating an alternating magnetic field from the first sensor coil group; a second step of the position detector obtaining a level of a pen signal which a pen, having stored the alternating magnetic field, generates as a response alternating magnetic field, by using at least the second sensor coil group; and a third step of the position detector deriving information regarding a position of the pen by using a two-dimensional distribution of the level of the pen signal at each of points of intersection of the plurality of electrodes of the first sensor coil group and the plurality of electrodes of the second sensor coil group.