Acoustic Wave Touch Detection Using Delay Template Matching
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Solution Overview
Problem
Conventional touch devices face issues such as slow response, high manufacturing costs, excessive power consumption, and decreased accuracy due to noise in ultrasonic sensor readings, particularly in resistive, infrared, and capacitive touch technologies.
Innovation Solution
A touch device utilizing a substrate with multiple sensors that detect acoustic waves and generate electrical signals, coupled with a processing module that calculates and compares received delay measurements to pre-stored templates to estimate touch location, reducing noise and improving accuracy without the need for costly electrical materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional ultrasonic sensors are used to detect touch location, then the device can determine touch position without costly conductive materials, but the estimation accuracy decreases due to noise in sensor readings
Solution Approach 1:
The system performs preliminary calibration by storing multiple delay measurements for each location on the substrate during a calibration phase. These pre-collected measurements are stored as templates in memory, allowing the system to compare against multiple reference values rather than relying on a single noisy measurement during actual touch detection
Solution Approach 2:
The system uses feedback by comparing the measured delay against multiple stored template values and selecting the template with the smallest difference. This feedback mechanism allows the system to iteratively refine its touch location estimation by finding the best match among multiple references, thereby improving accuracy without increasing hardware cost
2Measurement precision
If multiple measurements are averaged during calibration to improve accuracy, then the signal-to-noise ratio improves, but the calibration process time increases
Solution Approach 1:
The system performs more measurements than strictly necessary during calibration (excessive action) to ensure high accuracy templates are established. By collecting multiple measurements per location and averaging them, the system creates robust reference templates that improve signal-to-noise ratio, accepting the trade-off of longer calibration time as a one-time cost for improved ongoing performance
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
Enhances estimation accuracy and reduces power consumption and manufacturing costs by averaging multiple measurements during calibration, thereby improving the signal-to-noise ratio and eliminating the need for costly substrate processing.
Implementation Method 1
a plurality of sensors placed on a substrate for detecting acoustic waves and converting the acoustic signals to electrical signals
Data Source
AI summary
A touch device includes a plurality of sensors, a storage module and a processing module. The sensors are placed on a substrate for detecting acoustic waves and generating electrical signals. The storage module stores a plurality of templates of delay measurement for a plurality of locations on the substrate. The processing module is coupled to the sensors and to the storage module for calculating a received delay measurement and comparing the received delay measurement to the plurality of templates of delay measurement to estimate touch location. A detection method for the touch device is also provided.