Radial Wedge Transducer for Acoustic Touch Sensor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional surface acoustic wave touch sensors face ambiguity in accurately locating multiple simultaneous touches due to overlapping attenuation coordinates, making it difficult to determine the correct association of X and Y locations.
Innovation Solution
The implementation of a radial wedge transducer with a piezoelectric element and a reflection surface that generates and receives acoustic waves in a radial pattern, allowing for diverging waves to cover the touch region without the need for a bezel, enabling clear detection of multiple touches by using a fanned-out beam pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional linear transducers are used to generate surface acoustic waves, then the touch sensor can detect touch locations, but multiple simultaneous touches cause ambiguity in determining correct coordinate associations
Solution Approach 1:
The patent applies curvature by using a radial wedge transducer with a curved reflection surface that generates surface acoustic waves in a radial (fan-shaped) pattern rather than a linear pattern. This curved geometry causes the acoustic waves to diverge radially across the touch surface, creating unique angular paths from the source to different touch locations. When multiple touches occur, each touch attenuates waves along its specific radial path, and the angular information preserved in the radial pattern allows the system to uniquely identify and associate each touch with its correct coordinates, eliminating the ambiguity that plagues linear transducer systems.
2Measurement precision
If radial wedge transducer with curved reflection surface is used, then multiple simultaneous touches can be accurately located, but the device complexity increases
Solution Approach 1:
The radial wedge transducer with curved reflection surface serves multiple functions: it generates surface acoustic waves, shapes them into a radial pattern, and provides angular information for touch location detection. This single component performs what would otherwise require separate linear transducers plus additional processing hardware, simplifying the overall system while enabling accurate multiple touch detection.
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 effectively resolves the ambiguity of multiple touches by ensuring that each touch location can be accurately determined through the radial pattern's diverging waves, enhancing the precision and clarity of touch detection on the touch surface.
Implementation Method 1
A piezoelectric element connected to a first surface of the radial wedge
Implementation Method 2
the boundary surface is capable of converting between first acoustic waves reflecting off of the reflection surface and second acoustic waves propagating in a radial pattern on the touch substrate
Implementation Method 3
A radial wedge connects on a first surface with a piezoelectric element. The radial wedge has a reflection surface and a boundary surface
Data Source
AI summary
Radial transducers are provided for acoustic touch sensors. Different radial transducer arrangements may allow for locating multiple simultaneous touches without ambiguity, in some embodiments without a bezel. Instead of transmitting acoustic waves along a line to be reflected at multiple points, surface acoustic waves are transmitted in a radial wave pattern. Surface acoustic waves are transmitted along different angles spread out over at least part of the touch region. Various techniques may be used to generate the radial wave pattern, such as a convex wedge of a wedge transducer, interference patterns, a curved piezoelectric element, a curved reflector, a curved edge of the substrate, a curved grating, or one or more lenses. These devices for controlling the spread of the surface acoustic waves may alternatively be used for control of the surface acoustic rays for transmission along a single line or just along two lines (e.g., X and Y axes).