Touch Controller Signal Routing for Active Stylus Data
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Solution Overview
Problem
Signal attenuation occurs when transmitting data communications from a touch screen device to an active stylus due to differing grounding connections between the user's body and the touch screen controller, leading to inaccurate data detection.
Innovation Solution
A touch panel system with intersecting first and second electrodes and a touch controller circuit that selectively passes a modulated data signal through electrodes not associated with the touch location while grounding those electrodes that are, creating a common ground reference to prevent signal attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the touch screen controller transmits data signals through the touch panel during normal operation, then data communication with the active stylus is enabled, but signal attenuation occurs due to the user's hand providing an alternative ground reference path
Solution Approach 1:
The touch panel electrodes are segmented into two functional groups: first electrodes that transmit data signals and second electrodes that provide ground reference. This segmentation allows the system to separate signal transmission paths from ground reference paths, preventing the user's hand from creating alternative ground paths that would attenuate the signal.
Solution Approach 2:
Different regions of the touch panel are assigned different functions: areas with first electrodes are optimized for signal transmission while areas with second electrodes are optimized for ground reference. This local differentiation ensures that signal transmission occurs only where needed, avoiding interference from the user's hand in other regions.
2Device complexity
If the touch screen controller uses the same electrodes for both touch detection and data transmission, then device complexity is reduced, but signal attenuation and inaccurate data detection occur
Solution Approach 1:
The electrode system is divided into distinct first and second electrodes with separate functions. First electrodes handle data transmission while second electrodes handle ground reference and touch detection. This segmentation resolves the conflict between using the same electrodes for multiple functions versus using separate electrodes, achieving both reliability and manageable complexity.
Solution Approach 2:
The touch panel system achieves multi-functionality by integrating both data transmission and touch detection capabilities within a unified electrode structure. The first and second electrodes work together to provide both communication and sensing functions, eliminating the need for completely separate systems while maintaining accuracy.
3Ease of operation
If the user's hand provides a ground reference for the active stylus, then the stylus can detect touch input, but the user's body creates signal attenuation when transmitting data to the stylus
Solution Approach 1:
The ground reference function is extracted from the user's body and transferred to the second electrodes of the touch panel. By providing a dedicated ground reference path through the panel's second electrodes, the system separates the ground reference function from the user's body, eliminating the body's interfering effect on signal transmission while maintaining the ability to detect touch input.
Solution Approach 2:
The second electrodes act as an intermediary between the user's hand and the data transmission system. They provide a controlled ground reference path that mediates the interaction, allowing touch detection while preventing the user's body from creating unwanted signal attenuation paths.
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 ensures high-amplitude, consistent data signal reception by the active stylus by isolating the user's hand from the data transmission signal, thereby mitigating signal attenuation and enabling accurate data communication.
Implementation Method 1
a capacitive sensing mode to detect a touch made to the touch screen device by a user through either, or both, a body part of the user or the active stylus 14 being manipulated by the user
Implementation Method 2
selectively cause first ones of the line driver circuits to pass the modulated data signal through the first and second electrodes
Implementation Method 3
The hand of the user may grab the touch screen device 12 as generally indicated at reference 18. Still further, the hand of the user may rest on the surface of the touch screen device 12 while manipulating the active stylus 14 as generally indicated at reference 20. The user's hand/finger/thumb and the active stylus 14 are grounded through a common ground connection using the user's body
Data Source
AI summary
A touch panel includes capacitive sensing electrodes and a touch controller operates in a first operating mode to detect a touch location on the touch panel. In a second operating mode, the touch controller transmits a modulated data signal through the touch panel to an active stylus. Each electrode is driven by a line driver circuit. A control circuit selectively actuates first ones of the line driver circuits to pass the modulated data signal to corresponding first ones of the electrodes which do not pass through a region of the touch panel associated with the location of the detected touch. Simultaneously, the control circuit selectively actuates second ones of the line driver circuits, different from said first ones of the line driver circuits, to ground corresponding second ones of the electrodes which do pass through the region of the touch panel associated with the location of the detected touch.