Acoustic Touch Sensor Using Reflecting Structures for Position Detection
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Solution Overview
Problem
Existing touch sensors lack versatility in determining the position of a touch, particularly as a switching element for technical devices, and are limited in their ability to accurately identify touch positions using acoustic waves.
Innovation Solution
A touch sensor comprising a substrate with a touch surface, transmitters for exciting acoustic waves, reflecting structures for modifying wave propagation, and receivers to detect changes in wave signals when the touch surface is contacted, allowing for precise determination of touch positions by analyzing signal patterns generated by the receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If acoustic waves are used to detect touch position, then the touch sensor can determine position, but the versatility as a switching element for technical devices is limited
Solution Approach 1:
The touch surface is divided into multiple segments by arranging reflecting structures at different positions. Each segment corresponds to a specific region between adjacent reflecting structures, allowing the system to identify touch position by detecting which segment's acoustic wave signal is modified, thereby enhancing versatility for different application scenarios while maintaining precision
Solution Approach 2:
Reflecting structures are introduced as intermediary elements between the acoustic wave source and detector. These structures reflect acoustic waves to create distinct signal patterns for different touch positions, enabling the system to function as a versatile switching element with multiple detectable states while preserving accurate position determination
2Measurement precision
If reflecting structures are added to modify wave propagation, then touch position can be determined, but device complexity increases
Solution Approach 1:
Instead of modifying the entire substrate uniformly, reflecting structures are strategically placed only at specific locations where they are needed to create distinct acoustic wave reflection patterns. This localized approach enables accurate touch position determination while minimizing the overall structural complexity and material usage
3Measurement precision
If acoustic wave energy is converted to volume sound waves upon touch, then touch position can be identified, but acoustic wave energy is lost
Solution Approach 1:
The conversion of acoustic wave energy to volume sound waves upon touch, which initially appears as energy loss, is actually utilized as the detection mechanism. This energy conversion creates a measurable signal change that enables accurate touch position identification, transforming what would be considered energy loss into a useful detection feature
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 touch sensor effectively identifies touch positions by converting acoustic waves into volume sound waves when the substrate is touched, creating a unique 'fingerprint' in the receiver signal that allows for accurate and versatile determination of touch locations, enabling precise input for technical devices.
Implementation Method 1
at least one transmitter for exciting acoustic waves in the substrate; a plurality of reflecting structures arranged across the surface for reflecting acoustic waves excited in the substrate
Implementation Method 2
if the surface is touched by a body part of the user or a touching means operated by the user at least a part of the acoustic wave energy excited in the substrate is converted into volume sound waves in the body part or the material of the touching means
Implementation Method 3
a plurality of reflecting structures arranged across the surface for reflecting acoustic waves excited in the substrate; each of the reflecting structures is configured to generate a reflected acoustic wave
Data Source
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AI summary
The invention relates to touch sensor and a method for determining a position of a touch, the touch sensor comprising: - a substrate (2) having a touch surface (21) configured to be touched by a user; - at least one transmitter for exciting acoustic waves in the substrate (2); - a plurality of reflecting structures (5, 5a, 5b) arranged across the touch surface (21) for reflecting acoustic waves excited in the substrate (2); - at least one receiver for receiving acoustic waves evoked by the transmitter, wherein - the reflecting structures (5, 5a, 5b) and the receiver are arranged relative to one another in such a way that an acoustic wave excited in the substrate (2) by the transmitter is reflected at the reflecting structures toward the receiver, and - if the touch surface (21) is touched by a body part (6) of the user or a touching means operated by the user at least a part of the acoustic wave energy excited in the substrate (2) is converted into volume sound waves in the body part or the material of the touching means thereby modifying the acoustic waves propagating in the substrate (2); and - evaluating means configured for determining the position of a touch on the touch surface (21) using a signal generated by the receiver upon receipt of acoustic waves evoked by the transmitter.