Radial layout for acoustic wave touch sensor
First Claim
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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; and
determine 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.
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Abstract
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.
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Citations
28 Claims
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1. A touch sensor for detecting a touch, the touch sensor comprising:
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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; and determine 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 22, 23, 26)
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14. A method for detecting a touch on a surface, the method comprising:
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generating a first acoustic fan with non-parallel propagation over the surface in an area for the touch; detecting a first angle associated with the touch from attenuation of the first acoustic fan along a first radial line; determining a point location of the touch as a function of the first angle; and determining a radius of the touch along the first radial line, the radius determined as a function of a width of attenuation, wherein generating the first acoustic fan comprises generating, via refraction by a first radial transducer, a first fan beam of surface acoustic waves. - View Dependent Claims (15, 16, 17, 18, 19, 24, 27)
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20. A touch sensor comprising:
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a substrate; a first radial transducer on the substrate, the first radial transducer configured to; generate or receive first surface acoustic waves on the substrate along different radial lines separated by an angle of at least 20°
in a touch region, the first surface acoustic waves comprising a first plurality of linear beams comprising an amplitude above a predefined threshold across a width of the beams; andone or more first receive transducers operable to receive the first surface acoustic waves along the different radial lines; a second transducer on the substrate, the second transducer configured to; generate or receive second surface acoustic waves on the substrate along parallel lines; a first linear reflective array configured to reflect the second surface acoustic waves from the second transducer in a parallel pattern in the touch region; and one or more second receive transducers configured to receive the second surface acoustic waves from parallel pattern; wherein the touch sensor is configured to; detect a first angle associated with a detected touch, on a surface of the substrate, 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; determined 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. - View Dependent Claims (21, 25, 28)
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Specification