Shared Receiver Ultrasonic Touch Detection on Metal
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Solution Overview
Problem
Current touch and force sensors, particularly those based on capacitive techniques, are costly to manufacture, prone to errors in testing, and do not perform well on materials like metal, which can provide an unpleasant 'squishy' sensation and are limited in detecting multi-touch inputs.
Innovation Solution
The use of shared receivers that listen to multiple transmitters, exchanging ultrasonic signals which can propagate through metal, allowing for touch and force detection without the need for physical buttons or mechanical deflection, enabling touch input detection on non-traditional surfaces like metal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitive-based touch sensors are used, then touch detection capability is achieved, but manufacturing cost increases and testing difficulty increases
Solution Approach 1:
The patent replaces capacitive-based touch sensing with acoustic wave-based sensing. Instead of using capacitors to detect touch, the system uses acoustic waves that propagate through the device housing, and detects changes in these waves when the housing is touched. This substitution eliminates the need for expensive capacitor manufacturing and testing while maintaining touch detection capability.
Solution Approach 2:
The patent introduces acoustic waves as an intermediary medium to detect touch input. Rather than directly measuring electrical capacitance changes, the system uses acoustic waves that interact with the housing material and user touch, providing an indirect but more manufacturable sensing mechanism.
2Measurement precision
If capacitive-based touch sensors are used, then touch detection is enabled, but testing complexity and cost increase
Solution Approach 1:
The patent replaces complex capacitive sensing circuits with simpler acoustic wave generation and detection systems. The acoustic approach uses piezoelectric materials to generate and detect waves, eliminating the need for complex capacitor testing procedures while maintaining touch detection functionality.
3Strength
If metal surfaces are used for device housing, then aesthetic and structural properties are improved, but touch sensing performance deteriorates with capacitive sensors
Solution Approach 1:
The patent introduces acoustic waves as an intermediary that can effectively propagate through metal housing materials. Unlike capacitive sensing that struggles with metal surfaces, acoustic waves interact well with the mechanical properties of metal, allowing reliable touch detection while maintaining the aesthetic and structural benefits of metal housing.
Solution Approach 2:
The patent changes the sensing parameter from electrical capacitance to acoustic wave propagation characteristics. This parameter change allows the system to effectively sense touch on metal surfaces, as acoustic waves interact with the mechanical properties of metal rather than its electrical properties.
4Measurement precision
If traditional capacitive sensors are used, then simple touch detection is achieved, but multi-touch and force detection capabilities are limited
Solution Approach 1:
The patent segments the acoustic sensing into multiple independent wave propagation paths through the housing. By using multiple acoustic wave generators and detectors positioned at different locations, the system can independently analyze each wave path to detect multiple simultaneous touch points and differentiate between them, enabling multi-touch capability.
Solution Approach 2:
The patent creates a universal acoustic sensing system that can detect multiple types of input simultaneously - single touch, multi-touch, light pressure, and hard pressure. The acoustic wave-based system provides a unified sensing mechanism that handles various input scenarios without requiring separate sensor systems.
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
This solution reduces manufacturing costs, improves accuracy by eliminating the need for capacitors, and allows for effective detection of touch and force on metal surfaces, including multi-touch inputs, providing a more pleasant user experience.
Implementation Method 1
a first transmitter to transmit a first propagating signal to a receiver through a propagating medium, wherein the first propagating signal propagates through a first region of the touch input medium
Implementation Method 2
exchanging ultrasonic signals which can propagate through metal
Implementation Method 3
the emitted signal propagating through the propagating housing medium is disturbed (e.g., the touch causes an interference with the propagated signal). By processing the received signals, a location and a force on the surface of the housing associated with the touch input are at least in part identified.
Data Source
AI summary
A touch input to a propagating medium is identified based on one or more of the following: (1) a determination that a third propagating signal (from a second transmitter to a first receiver) was interfered with while a first propagating signal (from a first transmitter to the first receiver) was not interfered with or (2) a determination that the second propagating signal (from a first transmitter to a second receiver) was interfered with while the fourth propagating signal (from the second transmitter to the second receiver) was not interfered with. In response to the touch input to the propagating medium being identified, a system which includes the first transmitter, the second transmitter, the first receiver, and the second receiver updates.