Touch Detection Electrode Array Using Hadamard Matrix Inversion Drive
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Solution Overview
Problem
Existing touch detecting devices face challenges in increasing sensitivity beyond what is achievable with conventional code division multiplex (CDM) systems without significant modifications.
Innovation Solution
A detecting device with a configuration of drive electrodes and detection electrodes that employs a predetermined number of phases for simultaneously supplying drive signals, including inversion drive with different potentials to adjacent electrodes, and utilizes Hadamard matrices to optimize signal processing and detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional CDM system is used to drive multiple drive electrodes simultaneously, then sensitivity in touch detection is improved, but further increase in sensitivity becomes difficult without significant modifications
Solution Approach 1:
The drive period is divided into two distinct drive periods: a first drive period where drive signals with different potentials are supplied to adjacent drive electrodes based on a Hadamard matrix, and a second drive period where the relation between electric potential and drive electrodes is shifted by one drive electrode. This segmentation allows the system to extract multiple types of detection signals that can be processed to achieve higher sensitivity beyond conventional CDM limits.
2Measurement precision
If drive signals with different potentials are supplied to adjacent drive electrodes (inversion drive), then detection accuracy is improved, but noise interference increases
Solution Approach 1:
The system acquires multiple detection signals from the detection electrode during different drive periods and processes these signals through specific calculations. By combining information from the first drive period (with inversion drive patterns) and the second drive period (with shifted patterns), the system can differentiate between actual touch signals and noise interference, effectively suppressing noise while maintaining high detection accuracy.
3Measurement precision
If multiple phases are used to simultaneously supply drive signals to drive electrodes, then sensitivity is enhanced, but resolution may be compromised
Solution Approach 1:
The system employs periodic inversion drive patterns using Hadamard matrices across multiple phases, where adjacent drive electrodes receive drive signals with different potentials that periodically change. This periodic action with structured patterns allows the detection electrode to capture phase-specific information that can be processed to maintain both high sensitivity and high resolution in touch detection.
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 enhances sensitivity in touch detection while maintaining resolution, effectively addressing the limitations of conventional CDM systems and reducing noise interference.
Implementation Method 1
capacitance generated between the drive electrodes and the detection electrode due to the drive signal
Data Source
AI summary
A detecting device includes a plurality of drive electrodes extending in a first direction and arrayed in a second direction, a detection electrode facing the drive electrodes in a direction orthogonal to the first direction and the second direction, a drive circuit configured to supply a drive signal to the drive electrodes, and a detector configured to detect proximity of an object to a detection region provided with the detection electrode based on an output from the detection electrode generated according to capacitance generated between the drive electrodes and the detection electrode due to the drive signal.