Radial transducer for acoustic wave touch sensor
First Claim
1. A transducer for an acoustic wave touch sensor having a touch substrate, the transducer comprising:
- a piezoelectric element; and
a radial coupling element connected on a first surface with the piezoelectric element, the radial coupling element having a reflection surface and a boundary surface, the boundary surface on the touch substrate, and the reflection surface positioned relative to the piezoelectric element such that the boundary surface is capable of converting, via refraction, between first acoustic waves reflecting off of the reflection surface and second acoustic waves propagating in a radial pattern on the touch substrate, the first acoustic waves being transmitted at a velocity less than the phase velocity of the second acoustic waves propagating on the touch substrate, the radial pattern diverging as a distance from the radial coupling element increases.
10 Assignments
0 Petitions
Accused Products
Abstract
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).
-
Citations
8 Claims
-
1. A transducer for an acoustic wave touch sensor having a touch substrate, the transducer comprising:
-
a piezoelectric element; and a radial coupling element connected on a first surface with the piezoelectric element, the radial coupling element having a reflection surface and a boundary surface, the boundary surface on the touch substrate, and the reflection surface positioned relative to the piezoelectric element such that the boundary surface is capable of converting, via refraction, between first acoustic waves reflecting off of the reflection surface and second acoustic waves propagating in a radial pattern on the touch substrate, the first acoustic waves being transmitted at a velocity less than the phase velocity of the second acoustic waves propagating on the touch substrate, the radial pattern diverging as a distance from the radial coupling element increases. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
Specification