Stylus Tilt Detection for Accurate Touch Position Correction
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Solution Overview
Problem
Conventional touch-sensing devices inaccurately determine the position of a stylus due to tilting, as they measure the width of the transmitter instead of the tip, leading to erroneous reports for right- and left-handed users.
Innovation Solution
A stylus with at least four receivers determines signal strength from multiple electrode lines oriented at different axes, calculating tilt direction and magnitude to correct the reported position by transmitting a response signal to the touch-sensing device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional touch-sensing devices measure the width of the transmitter to determine stylus position, then the measurement process is simple, but the position accuracy deteriorates due to tilting
Solution Approach 1:
The transmitter is segmented into multiple independent signal sources (first transmitter and second transmitter) positioned at different locations within the stylus. Each transmitter independently transmits signals to separate electrode lines, enabling the system to measure signal strength differences caused by tilting and calculate the actual tip position more accurately.
Solution Approach 2:
The system implements a feedback mechanism where the touch-sensing device receives signal strength information from multiple transmitters, calculates tilt direction and magnitude, determines corrected position information, and provides this feedback to compensate for the tilting error, thereby improving position accuracy.
2Measurement precision
If the stylus transmitter width is considered in position measurement, then the measurement covers the entire transmitter area, but erroneous position reports occur for tilted stylus positions
Solution Approach 1:
Instead of trying to measure the tip position directly when the stylus is tilted, the system inverts the approach by measuring the signal strength at multiple known transmitter positions and using the differential measurements to infer the tilt angle and correct the position calculation, thereby maintaining ease of operation while improving accuracy.
Solution Approach 2:
The system changes the measurement parameters from a single position measurement to multiple signal strength measurements at different transmitter locations. By analyzing the changes in signal strength parameters across multiple receivers, the system can calculate tilt direction and magnitude, then apply corrections to determine accurate touch position.
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 touch-position accuracy by correcting stylus position based on tilt direction and magnitude, ensuring precise measurements even with user tilting.
Implementation Method 1
At least four receivers (330) of the stylus (120) receive a signal emitted by an electrode line (210)
Data Source
AI summary
In one embodiment, a method includes receiving, at each of at least four receivers of a stylus, a signal from an electrode line oriented along a first axis of a touch-sensing device and determining, by a processor of the stylus, a signal strength of the signal at each of the at least four receivers of the stylus. The received signal has a different signal strength at each of the at least four receivers. The method includes determining, by the processor of the stylus, a tilt direction of the stylus based on the determined signal strength at a plurality of the at least four receivers, and providing, by a transmitter of the stylus, a response signal to the touch-sensing device. The tilt direction includes a direction of the stylus along a second axis of the touch-sensing device and the second axis is oriented in a different direction than the first axis.