Ultrasonic Touch Detection on Metal Surfaces
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Solution Overview
Problem
Current touch input detection technologies, such as capacitive and resistive sensing, face limitations in creative design flexibility, water-proofing, and reliability, especially on metal surfaces, due to inherent properties and susceptibility to disturbances, and require additional layers for accurate input detection.
Innovation Solution
An ultrasonic touch detection system using micromachined ultrasonic transducers (MUTs) that can detect touch inputs on various surfaces, including metals, by analyzing changes in reflected ultrasound signals and employing adaptive threshold updates or recurrent neural networks to differentiate between touch events and false positives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitive sensing technology is used to detect touch inputs, then touch detection capability is improved, but design flexibility and water-proofing are limited
Solution Approach 1:
The patent replaces capacitive sensing technology with ultrasonic sensing technology. The ultrasonic sensor detects touch inputs by measuring changes in ultrasonic signal reflections when an object contacts the surface, eliminating the need for capacitive layers and enabling use on metal surfaces and water-proof applications.
2Adaptability or versatility
If strain gauge pressure sensing technology is used on metal surfaces, then touch input detection is enabled, but reliability is reduced due to susceptibility to disturbances
Solution Approach 1:
The patent replaces strain gauge pressure sensing with ultrasonic sensing. The ultrasonic sensor measures touch by detecting changes in ultrasonic signal reflections and transmission characteristics, which are not affected by the same disturbances that impact strain gauges on metal surfaces.
3Measurement precision
If additional sensing layers are added to detect touch position, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The ultrasonic sensor performs multiple functions with a single component: it detects both the presence of touch inputs and determines touch position by analyzing the characteristics of reflected ultrasonic signals, eliminating the need for separate capacitive layers for position detection.
Solution Approach 2:
The patent uses changes in ultrasonic signal parameters (reflection coefficient, time of flight, frequency content) to extract multiple pieces of information including touch position, pressure, and contact area from a single sensor, reducing the need for additional sensing layers.
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 ultrasonic system enables reliable and flexible touch input detection on diverse surfaces without disrupting design aesthetics, improves sensitivity, and reduces power consumption, allowing for accurate identification of touch types and users.
Implementation Method 1
analyzing changes in reflected ultrasound signals
Implementation Method 2
transmitting emitted signals through the material layer towards an external surface
Data Source
AI summary
A method includes receiving energy data associated with an ultrasound input device coupled to a material layer. The energy data comprises a current energy value and past energy values associated with reflected ultrasound signals received at the ultrasound input device in response to the ultrasound input device transmitting emitted signals through the material layer towards an external surface of the material layer. The method can then include comparing the energy data with threshold data to generate a current trigger value for trigger data. The trigger data is indicative of an occurrence of a touch event when the current energy value exceeds a current threshold value of the threshold data. Then the method can include updating the threshold data based on the energy data, the trigger data, and the threshold data. Updating the threshold data comprises generating a subsequent threshold value.