Ultrasonic distance measure
First Claim
1. An ultrasonic distance measure comprising:
- a transmitting ultrasonic transducer and a receiving ultrasonic transducer, of which the resonant or resonance frequencies are changeable;
a driving section, which generates a frequency-modulated drive signal to drive the transmitting ultrasonic transducer and transmit an ultrasonic wave;
a transmitting control voltage generating section for generating a control voltage to change the resonant or resonance frequency of the transmitting ultrasonic transducer and applying the control voltage to the transmitting ultrasonic transducer that is going to transmit the ultrasonic wave;
a receiving control voltage generating section for generating a control voltage to change the resonant or resonance frequency of the receiving ultrasonic transducer and applying the control voltage to the receiving ultrasonic transducer when a controllable amount of time delay has passed since the drive signal was generated; and
a receiving section for sensing the intensity of a signal received as the ultrasonic wave at the receiving ultrasonic transducer,wherein the ultrasonic wave is transmitted from the transmitting ultrasonic transducer toward an object of measurement a number of times, reflected, and then received at the receiving ultrasonic transducer with the time delay changed every time, andwherein the ultrasonic distance measure calculates propagation time of the ultrasonic wave based on the time delay that makes the receiving section receive the ultrasonic wave as a signal with the highest intensity, and measures a distance to the object of measurement based on the propagation time.
1 Assignment
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Accused Products
Abstract
An ultrasonic distance measure includes: transmitting and receiving ultrasonic transducers with changeable resonant/resonance frequencies; a driving section generating a frequency-modulated drive signal to drive the transducer and transmit an ultrasonic wave; a transmitting control voltage generating section for generating a control voltage to change the resonant/resonance frequency of The transducer and applying it to the transducer in transmitting the ultrasonic wave; a receiving control voltage generating section for generating a control voltage to change the resonant/resonance frequency of the transducer and applying it to the transducer when a controllable amount of time delay has passed since The drive signal was generated; and a receiving section for sensing the intensity of a signal received as the ultrasonic wave at the transducer.
28 Citations
20 Claims
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1. An ultrasonic distance measure comprising:
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a transmitting ultrasonic transducer and a receiving ultrasonic transducer, of which the resonant or resonance frequencies are changeable; a driving section, which generates a frequency-modulated drive signal to drive the transmitting ultrasonic transducer and transmit an ultrasonic wave; a transmitting control voltage generating section for generating a control voltage to change the resonant or resonance frequency of the transmitting ultrasonic transducer and applying the control voltage to the transmitting ultrasonic transducer that is going to transmit the ultrasonic wave; a receiving control voltage generating section for generating a control voltage to change the resonant or resonance frequency of the receiving ultrasonic transducer and applying the control voltage to the receiving ultrasonic transducer when a controllable amount of time delay has passed since the drive signal was generated; and a receiving section for sensing the intensity of a signal received as the ultrasonic wave at the receiving ultrasonic transducer, wherein the ultrasonic wave is transmitted from the transmitting ultrasonic transducer toward an object of measurement a number of times, reflected, and then received at the receiving ultrasonic transducer with the time delay changed every time, and wherein the ultrasonic distance measure calculates propagation time of the ultrasonic wave based on the time delay that makes the receiving section receive the ultrasonic wave as a signal with the highest intensity, and measures a distance to the object of measurement based on the propagation time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An ultrasonic distance measure comprising:
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a transmitting ultrasonic transducer and a receiving ultrasonic transducer, of which the resonant or resonance frequencies are changeable; a driving section, which generates a measuring drive signal to drive the transmitting ultrasonic transducer and transmit a measuring ultrasonic wave, the measuring drive signal including a first drive signal that is frequency-modulated and generated a number of times at a predetermined time interval; a transmitting control voltage generating section for generating a first control voltage to change the resonant or resonance frequency of the transmitting ultrasonic transducer and applying the control voltage to the transmitting ultrasonic transducer that is going to transmit the ultrasonic wave; a receiving control voltage generating section for generating the first control voltage to change the resonant or resonance frequency of the receiving ultrasonic transducer and applying the first control voltage to the receiving ultrasonic transducer when a predetermined time delay has passed since the first drive signal was generated each time; and a receiving section for sensing the intensity of a signal received as the ultrasonic wave at the receiving ultrasonic transducer, wherein the ultrasonic wave is transmitted from the transmitting ultrasonic transducer toward an object of measurement a number of times in response to the first drive signal with one of the time interval and time delay fixed and the other changed, reflected as a first reflected wave each time, and then received at the receiving ultrasonic transducer, and wherein the ultrasonic distance measure calculates propagation time of a first ultrasonic wave based on the intensity of a first received signal detected at the receiving section each time and measures a distance to the object of measurement based on the propagation time. - View Dependent Claims (15, 16, 17, 18, 19)
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20. An ultrasonic range finding method comprising the steps of:
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transmitting an ultrasonic wave toward an object of measurement by driving a transmitting ultrasonic transducer with a frequency-modulated drive signal applied thereto and with its resonant or resonance frequency changed substantially in sync with the frequency modulation of the drive signal; and receiving the ultrasonic wave, which has been reflected from the object of measurement, at the receiving ultrasonic transducer with the resonant or resonance frequency thereof changed after a controllable amount of time delay has passed since the drive signal was generated, wherein the transmitting step and the receiving step are carried out a number of times with the time delay changed each time, and wherein the propagation time of the ultrasonic wave is obtained based on the time delay that makes the receiving ultrasonic transducer receive an ultrasonic wave with the highest signal intensity, and the distance to the object of measurement is calculated based on the propagation time.
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Specification