Acoustic Touch Screen Using Sound Pickup Time Differences
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Solution Overview
Problem
Capacitive touch screens face limitations such as non-operability with gloves, high drift rates, and high costs, necessitating the development of an alternative touch screen technology that offers improved accuracy, usability, and reduced costs.
Innovation Solution
A touch screen that utilizes sound waves generated by touch operations to determine the coordinates of a touch point through a plurality of sound pickups, which filter effective frequencies and calculate the touch position using time differences, allowing for accurate and glove-compatible touch control without medium limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a capacitive touch screen is used, then accuracy and sensitivity are improved, but cost increases and glove operation becomes impossible
Solution Approach 1:
The patent replaces the electrical field-based capacitive sensing mechanism with an acoustic wave-based sensing mechanism. Sound pickups detect mechanical vibrations generated by touch operations, fundamentally changing the sensing principle from electrical to acoustic, thereby achieving glove compatibility while maintaining accuracy
Solution Approach 2:
The patent changes the sensing parameter from electrical capacitance to acoustic vibration frequency and time of arrival. By detecting the acoustic characteristics of touch operations rather than electrical properties, the system achieves both glove operation capability and accurate positioning
2Measurement precision
If a capacitive touch screen is used, then sensitivity is improved, but drift rate increases
Solution Approach 1:
The patent employs multiple sound pickups that provide redundant measurement channels. By comparing the time of arrival of acoustic waves at different pickups, the system creates a cross-validated positioning mechanism that reduces drift and improves reliability through feedback from multiple independent sensors
3Ease of operation
If acoustic sensors are used to detect touch operations, then glove operation becomes possible and cost is reduced, but measurement precision may be affected by noise
Solution Approach 1:
The patent divides the sensing function across multiple sound pickups distributed at different positions. Each pickup independently detects acoustic waves, and the system segments the measurement task to achieve accurate triangulation of touch position while maintaining robustness against individual sensor noise
Solution Approach 2:
The patent exploits the mechanical vibration characteristics of touch operations on the screen surface. By detecting the vibrational acoustic waves generated by finger taps or writes, the system achieves noise-resistant detection that maintains precision while enabling glove operation
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 user experience by enabling accurate touch point positioning across various devices, reduces manufacturing costs, and supports diverse touch control operations, making it competitive in terms of cost and performance for applications like mobile phones and large displays.
Implementation Method 1
picks up sound waves generated by touch operation to determine coordinates of a touch point to implement accurate positioning of the touch point by virtue of a plurality of sound pickups
Implementation Method 2
calculate effective sound signal pickup time differences of each pickup on the basis of the recorded pickup time
Data Source
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Figure 3
AI summary
A touch screen and a terminal are disclosed. The touch screen comprises: a touch panel, at least three pick-up devices, and a data calculation module, whereof: the touch panel covers the pick-up devices and is used to provide a touch operation platform; the pick-up devices are used to detect effective sound signals produced by touch operations, and to record detection time; and the data calculation module is used to ascertain, on the basis of recorded detection times, the time differential of the effective sound signal detected by each pick-up device, and to calculate the position of a touch-point by using the time differential and the path differential from a touch-point to each pick-up device.