Capacitive Touch Panel Dual-Layer Force Sensor Segmentation
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Solution Overview
Problem
Capacitive touch panels struggle to simultaneously detect multiple touch input events and force applied at different points, and they are limited in detecting non-conductive objects, with existing solutions either reducing the frequency of operation or failing to accurately measure multiple forces independently.
Innovation Solution
A capacitive touch sensing device with an array of drive and sense electrodes, where drive electrodes are split into sections and force sensing electrodes overlap only one section, allowing independent measurement of force and proximity without reducing the operating frequency, enabling accurate detection of multiple objects and forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If force sensing devices are incorporated into projected capacitive touch panels to detect force and multiple touches, then the ability to detect multiple simultaneous touch input events and force is improved, but the operating frequency is reduced and measurement accuracy is compromised
Solution Approach 1:
The drive electrode is divided into two separate sections: a first drive electrode section that operates at high frequency for touch detection, and a second drive electrode section that operates at low frequency for force sensing. This segmentation allows each section to be optimized for its specific function without compromising the other, resolving the contradiction between multi-touch capability and operating frequency.
2Measurement precision
If force sensing electrodes overlap multiple drive electrode sections to measure multiple forces independently, then the ability to measure multiple forces is improved, but the device complexity and signal interference increase
Solution Approach 1:
The force sensing electrode is positioned to overlap only with the second drive electrode section, creating a localized sensing region. This local quality approach allows the force sensing function to be confined to a specific area, enabling independent force measurement while minimizing interference with the first drive electrode section and reducing overall device complexity.
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
The solution allows for accurate and independent measurement of force and touch location for multiple objects, enhancing the device's ability to detect small or distant objects and maintain high-frequency operation, thus improving the overall accuracy and reliability of touch input detection.
Implementation Method 1
a first mutual coupling capacitor, 23, formed between the drive electrode 20 and sense electrode 21
Implementation Method 2
the force sensing electrodes, SB, are arranged so that they overlap the second drive electrode sections, DB and thereby form parallel plate capacitors
Data Source
AI summary
A capacitive touch panel includes a first substrate and a second substrate arranged relative to the first substrate. A plurality of drive electrodes are arranged on the first substrate, wherein each drive electrode comprises a first drive electrode section and a second drive electrode section. In addition, a plurality of sense electrodes are arranged on the second substrate, the plurality of sense electrodes including touch sensing electrodes and force sensing electrodes. At least part of a sense electrode of the plurality of sense electrodes forms a force sensitive coupling capacitance with a second drive electrode section and not with a first drive electrode section.