Touch Sensor Controller Segmentation for Retransmission Compensation
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Solution Overview
Problem
Capacitive touch sensors face inaccuracies due to poor coupling between users and devices, leading to missed or incorrectly reported touches, particularly caused by retransmission effects and varying grounding environments.
Innovation Solution
The implementation of a touch sensor system with a controller that sends multiple types of signals and analyzes responses to accurately detect touches, including methods to compensate for retransmission and grounding issues by comparing signal effects between lines and adjusting measurements accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a capacitive touch sensor is used to detect touches, then touch position can be detected, but retransmission effects cause inaccurate measurements and missed touches
Solution Approach 1:
The touch sensor controller segments the detection process into multiple phases: a first set of lines is driven during a first time period while a second set of lines is driven during a second time period. This temporal segmentation allows the system to isolate and identify retransmission effects by comparing measurements taken at different times, thereby improving measurement precision and reliability
Solution Approach 2:
The system uses feedback by comparing the measurement from the first time period with the measurement from the second time period. When a retransmission effect is detected through this comparison, the system adjusts or discards the affected measurement, ensuring accurate touch detection despite the presence of retransmission effects
2Adaptability or versatility
If multiple touches are detected simultaneously on different nodes, then comprehensive touch input is captured, but retransmission of drive signal causes unexpected signal coupling and measurement errors
Solution Approach 1:
The detection process is segmented into multiple time periods where different sets of lines are driven sequentially. This allows the system to capture multi-touch inputs while preventing retransmission errors by isolating the drive signals in time, enabling accurate position detection even when multiple touches occur simultaneously
Solution Approach 2:
The controller acts as an intermediary by introducing a time-based mediation mechanism. By driving different sets of lines at different times and comparing the results, the controller can identify and correct retransmission effects, maintaining measurement precision while preserving full multi-touch capability
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 enhances the accuracy of touch detection, effectively mitigating retransmission and grounding-related inaccuracies, allowing for precise identification of touch positions even in complex coupling scenarios.
Implementation Method 1
When an object touches or comes within proximity of the surface of the capacitive touch screen, a change in capacitance may occur within the touch screen at the location of the touch or proximity.
Data Source
AI summary
In one embodiment, a method includes sending a first set of signals to a first set of lines of a touch sensor. The method also includes receiving a second set of signals on a second set of lines of the touch sensor in response to sending the first set of signals. The second set of lines are capacitively coupled to the first set of lines. The method includes sending a third set of signals and receiving a fourth set of signals. The fourth set of signals is capacitively generated based on the third set of signals. The method also includes determining a fifth set of signals by compensating the second set of signals based on the fourth set of signals and determining whether a touch occurred based on the fifth set of signals.