Acoustic wave sensor with EMAT drive
First Claim
Patent Images
1. An acoustic wave touch sensor comprising:
- a body with an acoustic wave cavity formed therein and defined by a raised area, the acoustic wave cavity having a touch surface and at least a portion of the acoustic wave cavity being formed of an electrically conducting material; and
an electromagnetic acoustic transducer positioned adjacent to a surface of the acoustic wave cavity opposite the touch surface, the electromagnetic acoustic transducer having a primary coil generating a resonant acoustic wave in the acoustic wave cavity and a pickup coil providing an electrical output signal, wherein a touch on the touch surface produces a detectable change in the electrical output signal.
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Abstract
An acoustic wave sensor includes an electromagnetic acoustic transducer to generate a resonant acoustic wave substantially trapped in an acoustic wave cavity. The acoustic wave cavity is defined by a radially symmetric raised surface. The electromagnetic acoustic transducer includes a spiral primary coil to generate the acoustic wave in the acoustic wave cavity and a concentric spiral pickup coil to pick up an electrical signal representing the acoustic wave in the cavity. A noise canceling coil portion is used to cancel spurious noise induced by the primary coil from the pickup coil to provide an output signal representing the acoustic wave energy in the cavity 12.
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Citations
43 Claims
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1. An acoustic wave touch sensor comprising:
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a body with an acoustic wave cavity formed therein and defined by a raised area, the acoustic wave cavity having a touch surface and at least a portion of the acoustic wave cavity being formed of an electrically conducting material; and
an electromagnetic acoustic transducer positioned adjacent to a surface of the acoustic wave cavity opposite the touch surface, the electromagnetic acoustic transducer having a primary coil generating a resonant acoustic wave in the acoustic wave cavity and a pickup coil providing an electrical output signal, wherein a touch on the touch surface produces a detectable change in the electrical output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An acoustic wave sensor comprising:
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a body with a radially symmetric raised surface defining an acoustic wave cavity with at least a portion of the acoustic wave cavity being formed of an electrically conducting material; and
an electromagnetic acoustic transducer positioned adjacent one surface of the acoustic wave cavity, the electromagnetic transducer including a pair of spiral coils, one coil forming a primary coil generating a resonant acoustic wave in the acoustic wave cavity and the other coil forming a pickup coil. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. An acoustic wave sensor comprising:
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a body with a domed surface thereon defining an acoustic wave cavity with at least a portion of the acoustic wave cavity being formed of an electrically conducting material; and
an electromagnetic acoustic transducer having a spiral primary coil portion generating a resonant acoustic wave in the acoustic wave cavity, a spiral pickup coil portion and a spiral noise canceling coil portion, the acoustic wave cavity overlying at least the primary coil portion and the pickup coil portion. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. An acoustic wave sensor comprising:
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a body with an acoustic wave cavity formed therein and defined by a raised area, at least a portion of the acoustic wave cavity being formed of an electrically conducting material; and
an electromagnetic acoustic transducer having a primary coil portion generating a resonant acoustic wave in the acoustic wave cavity, a pickup coil portion providing an output signal and a noise canceling coil portion adjacent to at least one of the other coil portions to reduce noise in the output signal, the acoustic wave cavity overlying at least the primary coil portion and the pickup coil portion.
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39. An acoustic wave sensor comprising:
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a body with a radially symmetric raised surface defining an acoustic wave cavity with at least a portion of the acoustic wave cavity being formed of an electrically conducting materials; and
an electromagnetic acoustic transducer positioned adjacent one surface of the acoustic wave cavity, the electromagnetic transducer including a pair of magnets positioned side by side wherein the north pole of one magnet is adjacent the south pole of the other magnet and the boundary between the magnets is aligned with a centerline of the acoustic wave cavity, and the electromagnetic transducer including a pair of concentric spiral coils one coil forming a primary coil generating an acoustic wave in the acoustic wave cavity and another coil forming a pickup coil. - View Dependent Claims (40, 41, 42, 43)
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Specification