Touch sensitive device employing bending wave vibration sensing and excitation transducers
First Claim
1. A touch sensitive apparatus, comprising:
- a touch plate;
a plurality of sensors coupled to the touch plate, each of the sensors configured to sense bending waves in the touch plate;
an excitation transducer coupled to the touch plate and configured to induce bending waves in the touch plate;
a plurality of active buffer circuits, each of the active buffer circuits respectively coupled to one of the sensors; and
a controller coupled to the sensors via the active buffer circuits and to the excitation transducer via a non-actively buffered connection, the controller configured to compute information related to a touch on the touch plate responsive to sense signals received by the sensors.
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Accused Products
Abstract
A touch sensitive apparatus includes a touch plate to which several pickup sensors and at least one excitation transducer are coupled. Each of the sensors is configured to sense bending waves in the touch plate, and the excitation transducer is configured to induce bending waves in the touch plate. The apparatus may further include active buffer circuits, wherein each of the active buffer circuits is coupled to one of the sensors. A controller is coupled to the sensors via the active buffer circuits and to the excitation transducer via a non-actively buffered connection. The controller is configured to compute a location of a contact on the touch plate responsive to sense signals received from the sensors. The apparatus may be used to perform a variety of calibrations, including touch plate and sensor calibrations. Changes in touch sensing apparatus calibration and performance may be detected and tracked over time.
193 Citations
54 Claims
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1. A touch sensitive apparatus, comprising:
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a touch plate;
a plurality of sensors coupled to the touch plate, each of the sensors configured to sense bending waves in the touch plate;
an excitation transducer coupled to the touch plate and configured to induce bending waves in the touch plate;
a plurality of active buffer circuits, each of the active buffer circuits respectively coupled to one of the sensors; and
a controller coupled to the sensors via the active buffer circuits and to the excitation transducer via a non-actively buffered connection, the controller configured to compute information related to a touch on the touch plate responsive to sense signals received by the sensors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A method for use with a touch sensitive device comprising a touch plate to which an excitation transducer and a plurality of sensors are respectively coupled, the method comprising:
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applying an excitation signal generated by the excitation transducer to the touch plate and sensing the excitation signal by each of the sensors;
determining a transfer function of an input at the excitation transducer to an output at each of the sensors;
determining, for each of the sensors, a dispersion corrected impulse response using the transfer function; and
performing a calibration of the touch sensitive device using the respective dispersion corrected impulse responses. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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40. A method for use with a touch sensitive device comprising a touch plate to which an excitation transducer and a plurality of sensors are respectively coupled, the method comprising:
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applying an excitation signal generated by the excitation transducer to the touch plate and sensing the excitation signal by each of the sensors;
determining a transfer function of an input at the excitation transducer to an output at each of the sensors;
measuring a phase component of a frequency response associated with the excitation signal sensed by each of the sensors; and
performing a calibration of the touch plate using the measured phase components. - View Dependent Claims (41, 42, 43, 44, 45)
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46. A method for use with a touch sensitive device comprising a touch plate to which an excitation transducer and a plurality of sensors are respectively coupled, the method comprising:
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applying an excitation signal generated by the excitation transducer to the touch plate and sensing the excitation signal by each of the sensors;
determining a transfer function of an input at the excitation transducer to an output at each of the sensors;
calculating, in the time domain, an impulse response for each of the sensors using the transfer function;
measuring time of first energy arrival to each of the sensors;
calculating a distance from the excitation transducer to each of the sensors using the measured times of first energy arrival; and
calculating dimensions of the touch plate using the calculated transducer-to-sensor distances. - View Dependent Claims (47, 48)
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49. A touch sensitive device, comprising means for applying an excitation signal to a touch plate;
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means for sensing the excitation signal at each of four corners of the touch plate;
means for determining a transfer function of an input at the excitation signal applying means to an output at each of the sensing means;
means for determining a dispersion corrected impulse response using the transfer function for each of the sensing means; and
means for performing a calibration of the touch sensitive device using the respective dispersion corrected impulse responses. - View Dependent Claims (50, 51, 52)
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53. A touch sensitive device, comprising:
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means for applying an excitation signal to a touch plate;
means for sensing the excitation signal at each of four corners of the touch plate;
means for determining a transfer function of an input at the excitation signal applying means to an output at each of the sensing means;
means for measuring a phase component of a frequency response associated with the excitation signal sensed by each of the sensing means; and
means for performing a calibration of the touch plate using the measured phase components.
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54. A touch sensitive device, comprising:
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means for applying an excitation signal to a touch plate;
means for sensing the excitation signal at each of four corners of the touch plate;
means for determining a transfer function of an input at the excitation signal applying means to an output at each of the sensing means;
means for calculating, in the time domain, an impulse response for each of the sensing means using the transfer function;
means for measuring time of first energy arrival to a sensor of each of the sensing means;
means for calculating a distance from a transducer of the excitation signal applying means to the sensor of each of the sensing means using the measured times of first energy arrival; and
means for calculating dimensions of the touch plate using the calculated transducer-to-sensor distances.
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Specification