Active Stylus Signal Control for Capacitive Touch Precision
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Solution Overview
Problem
Conventional touch-screen devices face challenges in accurately distinguishing between finger and stylus inputs due to interference from electrical signals, leading to inaccuracies in touch sensing, and conventional styluses are passive, unable to actively control the input signals in capacitive touch sensors.
Innovation Solution
A stylus pen with a conductive tip, peak signal detector, phase discriminator, and controller that actively generates signals to interact with capacitive sensing devices, allowing for precise input control and discrimination between different touch sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional passive stylus pens are used with capacitive touch screens, then the stylus can physically contact the screen for input, but the stylus cannot actively control or generate sensing signals, limiting input precision and control capability
Solution Approach 1:
The patent replaces the passive mechanical contact-based stylus with an active electronic system that generates and controls sensing signals electronically. The stylus incorporates a controller that actively manages signal generation and transmission, substituting the passive mechanical interaction with active electronic control to enhance measurement precision and control capability.
Solution Approach 2:
The stylus is designed with self-contained electronic components including a controller, signal generator, and peak detector that enable it to autonomously generate and process sensing signals without requiring external active control. This self-service capability allows the stylus to actively control its own signal output and maintain precise input control independently.
2Reliability
If conventional touch sensing methods are used without active stylus control, then the system can detect touch inputs, but electrical interference and error sources cause inaccuracies in the touch sensing signals
Solution Approach 1:
The stylus incorporates a peak detector and controller that monitor the sensing signals in real-time and provide feedback to adjust signal generation. This feedback mechanism allows the system to compensate for electrical interference and error sources by dynamically adjusting the signal output to maintain accurate touch input detection despite environmental noise.
Solution Approach 2:
The active stylus controller proactively generates controlled signals that preemptively counteract the effects of electrical interference before it degrades signal accuracy. By actively managing signal generation and timing, the system prevents interference from causing measurement errors rather than merely reacting to them after they occur.
3Reliability
If physically tethered stylus pens are used to ensure electrical integration with the touch-screen device, then reliable signal transmission is achieved, but the stylus becomes inconvenient to handle and susceptible to wear on connecting components
Solution Approach 1:
The patent extracts the electrical connection components from the stylus by implementing wireless communication capability. The stylus controller transmits signals wirelessly to the touch-screen device, removing the physical tether and associated connecting components that cause wear and handling inconvenience, while maintaining reliable signal transmission through wireless communication protocols.
4Measurement precision
If the stylus tip is made small enough to avoid interfering with electric field lines, then capacitive sensing can detect the tip, but the tip becomes too small to provide stable and accurate input control
Solution Approach 1:
The patent replaces reliance on the physical size and shape of the stylus tip for input control with active electronic signal generation. The controller generates controlled sensing signals that are transmitted through the tip, allowing the tip to remain small for detection purposes while the electronic signal control provides the necessary stability and precision for accurate input control.
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
Enables accurate and active input control on any capacitive touch-screen device, improving interaction precision and reducing errors caused by electrical interference.
Implementation Method 1
a mutual capacitance CM is formed between the drive electrode 114 and sense electrode 116 at a touch pixel
Implementation Method 2
A touch-sensing signal output from a touch-screen can be a composite signal, for example, that includes one or more signals caused by a touch and one or more signals caused by other sources, such as electrical interference
Implementation Method 3
a peak signal detector and a phase discriminator that are each electrically coupled to the conductive tip, and a controller that is configured to receive a signal from the peak signal detector
Implementation Method 4
a peak signal detector and a phase discriminator that are each electrically coupled to the conductive tip, and a controller that is configured to receive a signal from the peak signal detector and a signal from the phase discriminator
Data Source
AI summary
Embodiments relate generally to control devices, such as human interface devices, configured for use with a touch-screen containing device. More specifically, the present invention relates to methods and various apparatus that are used to actively control the interaction of a handheld device, such as a stylus pen, with a touch-screen containing device. Embodiments of the invention provide a universal handheld device that is able to provide input to any type of capacitive sensing touch-screen containing device, regardless of the manufacturer or, in some embodiments, without knowledge of the touch-screen containing device manufacturer's specific capacitive touch-sensing detection techniques.