Touch Sensor Electrode Segmentation for Stylus Detection
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Solution Overview
Problem
Current touch sensors face challenges in accurately detecting the presence and position of objects, particularly active styluses, due to interference from large area touches and capacitive coupling issues, which affect the reliability and precision of touch input detection.
Innovation Solution
The implementation of a touch sensor array with a touch-sensor controller that employs specific voltage patterns and electrode configurations to systematically cycle through touch-sensitive areas, applying synchronization signals and reference voltages to reduce capacitive coupling and enhance object detection accuracy, including the use of touch exclusion bias patterns and synchronization bias patterns to minimize interference from large area touches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional touch sensor voltage patterns are used, then the touch sensor can detect object presence, but large area touches cause capacitive coupling interference that reduces detection accuracy
Solution Approach 1:
The touch sensor array is divided into multiple independently controllable electrode groups that can be selectively activated. By segmenting the electrode activation pattern, the system can isolate the detection signal from capacitive coupling interference caused by large area touches, thereby improving position detection accuracy while maintaining robustness against interference.
Solution Approach 2:
The touch sensor employs periodic voltage pattern cycling through multiple electrode groups in a systematic sequence. This periodic activation pattern allows the system to distinguish between capacitive coupling effects (which remain relatively constant) and actual touch signals (which vary with position), enabling accurate object position detection even during large area touches.
2Area of stationary object
If voltage patterns are applied to all electrodes simultaneously, then coverage is maximized, but capacitive coupling from large area touches interferes with detection
Solution Approach 1:
The electrode array is segmented into multiple groups that are activated in alternating patterns. This segmentation allows the system to maintain comprehensive area coverage over time while ensuring that at any given moment, only specific electrode groups are active, thereby reducing capacitive coupling interference and improving detection reliability.
Solution Approach 2:
The system uses periodic cycling of voltage patterns across different electrode groups to achieve both full area coverage and interference reduction. By systematically rotating through different electrode activation patterns, the system ensures all areas are monitored while minimizing the impact of capacitive coupling from large area touches on detection reliability.
3Measurement precision
If synchronization signals are transmitted continuously, then object detection is maintained, but energy consumption increases
Solution Approach 1:
The touch sensor controller transmits synchronization signals in periodic bursts rather than continuously, activating different electrode groups in alternating cycles. This periodic transmission maintains object detection capability by systematically covering the entire touch-sensitive area over time while significantly reducing average energy consumption compared to continuous signal transmission.
Solution Approach 2:
The continuous detection function is segmented into discrete periodic measurement cycles across different electrode groups. This segmentation allows the system to maintain measurement precision by systematically sampling the entire area while reducing energy consumption by keeping electrodes inactive during non-measurement periods.
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 improves the detection accuracy and precision of object positions, including active styluses, by reducing capacitive coupling and enhancing the reliability of touch input detection, even in the presence of large area touches, thereby improving the overall performance of touch sensors.
Implementation Method 1
When an object touches the surface of touch sensor array, a change in capacitance occurs within the touch screen at the position of the touch or proximity.
Implementation Method 2
Current touch sensors face challenges in accurately detecting the presence and position of objects, particularly active styluses, due to interference from large area touches and capacitive coupling issues
Data Source
AI summary
In certain embodiments, a method includes selecting, for a touch sensor including a first number of electrodes and a second number of electrodes, a first set of the first number of electrodes and a second set of the second number of electrodes. The first number of electrodes has a first orientation and the second number of electrodes has a second orientation. The second orientation being different from the first orientation. An overlap area is formed by an overlap of the first set and second set. The method also includes applying, during a first time period, a signal including a first pre-determined voltage to the first set and the second set such that, during the first time period, the overlap area has a first signal state; and applying, during a second time period, the signal to the first set and a second pre-determined voltage to the second set.