Touch Sensor Multi-Touch Detection Edge Effect Correction
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Solution Overview
Problem
Existing differential detection methods for touch sensors fail to correctly detect multi-touch inputs, especially when one input is located at the reference electrode, leading to incorrect differential outputs and misinterpretation of touch actions like pinching or zooming on multi-touch screens.
Innovation Solution
The proposed solution involves an input detection device and method that scans adjacent electrode lines, calculates differences between successive halves of these lines, and integrates these differences across the touch sensor interface, with a reset mechanism to correct for end-effects and a noise filter to remove low-level noise, ensuring accurate detection of multi-touch inputs even when they occur at the edges of the sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the differential detection method is applied to a touch sensor capable of multi-touch input detection, then noise from surrounding LCD driving can be reduced, but multi-touch inputs cannot be detected correctly when one of the inputs is located at the reference electrode
Solution Approach 1:
The patent divides the electrode lines into first electrode lines and second electrode lines based on their positions in the scanning sequence. By segmenting the electrode lines this way, the system can selectively pair them for differential detection while excluding cases where a multi-touch input occurs at the reference electrode, thereby maintaining noise reduction capability while improving detection accuracy.
Solution Approach 2:
The patent applies different detection strategies to different regions of the touch sensor. Specifically, it identifies electrode lines that may have multi-touch inputs at their reference electrode positions and applies special handling to those regions, while using standard differential detection for other regions. This localized approach preserves overall noise reduction while fixing the specific problem area.
2Productivity
If two electrodes to be acquired with a difference of detection data are applied with one of multi-touch inputs respectively, then the differential detection algorithm can process the data, but the difference cannot be acquired from the data detected from the two electrodes correctly
Solution Approach 1:
The patent performs preliminary identification of electrode lines that are likely to have multi-touch inputs at their reference electrode positions before performing the differential detection. By preparing and flagging these electrode lines in advance, the system can then apply appropriate corrections or exclusions during the differential calculation phase, ensuring accurate results without sacrificing processing efficiency.
Data Source
AI summary
An input detection device including: a reading part reading touch inputs from an input interface of a touch sensor by scanning every above two electrode lines which are adjacent on the scanning sequence from an end of the input interface to the opposite end, and acquiring a difference between detection data obtained from a half of the above two electrode lines which are successive and from the other half of the above two electrode lines which are successive; and a calculation part integrating the differences for the entire input interface to obtain touch information, wherein if an integration result obtained in the case where the above two lines stretches over the scanning finish end and the scanning start end is not satisfied with a predetermined value, the calculation part resets the detection data obtained from the electrode line located at the scanning finish end to be the predetermined value.