Radial layout for acoustic wave touch sensor

摘要

Surface acoustic waves in a radial pattern are used to detect touch. Different radial transducer arrangements may allow for locating multiple simultaneous touches without ambiguity. Instead of transmitting along a line to be reflected at multiple points, the surface acoustic waves are transmitted radially. The surface acoustic waves are transmitted along different angles in an angular span spread out over at least part of the touch region. Using acoustic waves traveling along intersecting paths, a point location of a touch may be determined by detection, in part, of at least one angle.

主权项

1. A touch sensor for detecting a touch, the touch sensor comprising:
a touch substrate having a top surface and a bottom surface, the top surface having a touch region; a first transducer configured to:
generate or receive first surface acoustic waves on the touch region, the first transducer comprising a first radial transducer; and a second transducer configured to:
receive or generate the first surface acoustic waves;detect a first angle associated with the touch from attenuation of the first surface acoustic waves along a first radial line;determine a point location of the touch as a function of the first angle; anddetermine a radius of the touch along the first radial line, the radius determined as a function of a width of attenuation, wherein the first surface acoustic waves have a first radial pattern, generated via refraction by the first radial transducer, with an angular span of at least 20° in the touch region, the first radial pattern comprising a first plurality of linear beams comprising an amplitude above a predefined threshold across a width of the beams, the first radial pattern being divergent as a distance from the first transducer increases.