Capacitive Touch Detection with Mutual and Self-Sensing Regions
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Solution Overview
Problem
Touchscreens in electronic devices often fail to accurately register user input, especially under poorly grounded conditions, leading to incorrect operations, unresponsiveness, and issues like ghost touches or false touch merging.
Innovation Solution
The implementation of a capacitive touch detection system that utilizes both mutual-sensing and self-sensing capacitive sensor regions to differentiate between single finger, multiple fingers, and thumb inputs, with the ability to correct for poor grounding conditions by analyzing touch patterns and using self-sensing data to validate mutual sensing data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mutual-sensing capacitive sensor regions are used to detect touch inputs, then touch detection capability is provided, but under poorly grounded conditions false touch merging and ghost touches occur reducing accuracy
Solution Approach 1:
The patent combines both mutual-sensing capacitive sensor regions and self-sensing capacitive sensor regions into a single touch detection system. The mutual-sensing regions provide primary touch detection capability while the self-sensing regions provide complementary data that is less susceptible to grounding issues. By merging the outputs of both sensor types and comparing their readings, the system achieves accurate touch detection even under poorly grounded conditions, preventing false touch merging and ghost touches.
2Adaptability or versatility
If traditional single sensor type is used, then device complexity is reduced, but ability to differentiate between finger types and correct grounding issues is insufficient
Solution Approach 1:
The patent implements a dual sensor system where both mutual-sensing and self-sensing capacitive sensor regions serve multiple functions. The mutual-sensing regions detect touch location and pressure, while the self-sensing regions provide grounding reference and alternative touch detection. Together, they enable the system to differentiate between various finger types (thumbs vs. fingers), detect ghost touches, and correct for grounding issues, achieving high adaptability without requiring separate specialized systems for each function.
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 enables reliable and accurate detection of multi-finger inputs even under poor grounding conditions, reducing errors and improving user experience by correctly identifying touch inputs and preventing false merging.
Implementation Method 1
In capacitive touchscreens, arrays of vertical and horizontal electrodes are placed on top of each other so as to form a matrix of capacitors. When a user provides input through the touch of a finger, the location of their touch is registered as a capacitance value of an electrode at the exact touch location.
Implementation Method 2
The plurality of mutual-sensing capacitive sensor regions is configured to measure mutual capacitance and generate mutual sensing touch values for each row and column
Implementation Method 3
The plurality of mutual-sensing capacitive sensor regions is configured to measure mutual capacitance and generate mutual sensing touch values for each row and column and measure self-sensing capacitance and generate self-sensing touch values for each row or column
Data Source
AI summary
In one embodiment, a method for operating an electronic device includes determining that a touch sensitive display is being contacted. The touch sensitive display includes a plurality of mutual-sensing capacitive sensor regions and an array of self-sensing capacitive sensor regions. The plurality of mutual-sensing capacitive sensor regions is arranged in rows and columns on the touch sensitive display. The array of self-sensing capacitive sensor regions is arranged in a row or a column on the touch sensitive display. The method may include obtaining mutual sensing touch values for each of the rows and the columns and self-sensing touch values for the row or the column. Based on the mutual sensing touch values and self-sensing touch values, the method includes determining whether a contacted region of the touch sensitive display is an impression of a single finger, multiple fingers, a single thumb, or multiple thumbs.