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US 8,555,724 B2Granted
Ultrasonic sensor
AssigneeDenso Corporation
InventorHidehito Terazawa
Life of this patent
Estimating the term…
Abstract
A single element of an ultrasonic transducer includes at least one combination of an equivalent series capacitor C1, an equivalent series inductor L1, and an equivalent series resistance R1. The ultrasonic transducer further includes an equivalent parallel capacitor C0. An inductor L2 is connected in series between the ultrasonic transducer and the drive circuit. A first resonance frequency of the equivalent series capacitor C1 and the equivalent series inductor L1 is F0. A second resonance frequency determined by at least the equivalent parallel capacitor C0 and the inductor L2 is Fp. A drive circuit drives the ultrasonic transducer while switching the driving frequency of the ultrasonic transducer to one of the resonance frequency F0 and the resonance frequency Fp.
Claims16
An ultrasonic sensor comprising:
- a single element of an ultrasonic transducer including
- at least one combination of an equivalent series capacitor C1, an equivalent series inductor L1, and an equivalent series resistance R1, and
- an equivalent parallel capacitor C0;
- a drive circuit configured to drive the ultrasonic transducer;
- and
- an inductor L2 connected in series between the ultrasonic transducer and the drive circuit,
- wherein the drive circuit is configured to switch a driving frequency of the ultrasonic transducer,
- a first resonance frequency of the equivalent series capacitor C1 and the equivalent series inductor L1 is F0,
- a second resonance frequency determined by at least the equivalent parallel capacitor C0 and the inductor L2 is Fp,
- the drive circuit is configured to drive the ultrasonic transducer while switching the driving frequency to one of the first resonance frequency F0 and the second resonance frequency Fp to have two kinds of directivity characteristics in different ranges and to have different detection areas, and
- the first resonance frequency F0 is different than the second resonance frequency Fp, the first resonance frequency F0 is calculated using a first capacitance, and an inductance of the equivalent series inductor L1 and the second resonance frequency Fp is calculated using a second capacitance different than the first capacitance and an inductance component.
8 more elements
An ultrasonic sensor comprising:
- a single element of an ultrasonic transducer including
- at least one combination of an equivalent series capacitor C1, an equivalent series inductor L1, and an equivalent series resistance R1, and
- an equivalent parallel capacitor C0;
- a drive circuit configured to drive the ultrasonic transducer;
- and
- a transformer TR connected between the ultrasonic transducer and the drive circuit,
- wherein the drive circuit is configured to switch a driving frequency of the ultrasonic transducer,
- a first resonance frequency of the equivalent series capacitor C1 and the equivalent series inductor L1 is F0,
- a second resonance frequency determined by at least the equivalent parallel capacitor C0 and the transformer TR is Fp,
- the drive circuit is configured to drive the ultrasonic transducer while switching the driving frequency to one of the first resonance frequency F0 and the second resonance frequency Fp to have two kinds of directivity characteristics in different ranges and to have different detection areas, and
- the first resonance frequency is different than the second resonance frequency, the first resonance frequency is calculated using a first capacitance and an inductance of the equivalent series inductor L1, and the second resonance frequency is calculated using a second capacitance different than the first capacitance and an inductance component.
8 more elements
A method for driving an ultrasonic sensor, the method comprising:
- causing a drive circuit to oscillate a single element of an ultrasonic transducer at a driving frequency, the ultrasonic transducer including at least one combination of an equivalent series capacitor C1, an equivalent series inductor L1, and an equivalent series resistance R1, the ultrasonic transducer further including an equivalent parallel capacitor C0, wherein one of an inductor L2 and a transformer TR is connected in series between the ultrasonic transducer and the drive circuit;
- switching the driving frequency to one of a first resonance frequency F0 and a second resonance frequency Fp to have two kinds of directivity characteristics in different ranges and to have different detection areas;
- calculating the first resonance frequency F0 using a first capacitance and an inductance of the equivalent series inductor L1;
- and
- calculating the second resonance frequency Fp using a second capacitance different than the first capacitance and an inductance component,
- wherein the first resonance frequency F0 is determined by the equivalent series capacitor C1 and the equivalent series inductor L1,
- wherein the second resonance frequency Fp is determined by at least the equivalent parallel capacitor C0 and the one of the inductor L2 and the transformer TR, and
- wherein the first resonance frequency F0 is different than the second resonance frequency Fp.
5 more elements
Dependencies are inferred from the claim text.