Ultrasonic distance sensor
First Claim
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1. An ultrasonic distance sensor comprising:
- an electroacoustic transducer adapted to alternately emit a burst of acoustic energy in response to a corresponding electrical drive signal and convert the portion of the burst of acoustic energy reflected back from a remote target to a corresponding electrical signal, said transducer being subject to unavoidable ringing for a known time interval after each emission of a burst of acoustic energy;
electronic circuitry operable to supply the electrical drive signal to said electroacoustic transducer and to receive therefrom the electrical signal corresponding to the reflected acoustic energy; and
a housing defining a housing envelope, said housing having an elongated body with first and second ends and a major face intersecting the first and second ends, a head mounted on the first end of said body with a portion extending transversely to the major face and outwardly from the intersection thereof with the first end, and a reflector mounted on the major face, the body having a compartment therein enclosing said electronic circuitry, the head supporting the transducer so that it is positioned to emit and receive acoustic energy in a direction toward the reflector, and the reflector being spaced from said transducer a distance at least half as great as that which acoustic energy travels during the known time interval.
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Abstract
A single transducer ultrasonic distance sensor is disclosed which provides for range sensing down to zero distance from the sensor housing envelope with an electroacoustic transducer subject to unavoidable ringing following emission of a burst of acoustic energy. The housing is configured and the transducer mounted therein so that an acoustic path at least half as great as the distance travelled by an acoustic signal during the transducer ringing interval is provided within the housing envelope.
26 Citations
14 Claims
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1. An ultrasonic distance sensor comprising:
- an electroacoustic transducer adapted to alternately emit a burst of acoustic energy in response to a corresponding electrical drive signal and convert the portion of the burst of acoustic energy reflected back from a remote target to a corresponding electrical signal, said transducer being subject to unavoidable ringing for a known time interval after each emission of a burst of acoustic energy;
electronic circuitry operable to supply the electrical drive signal to said electroacoustic transducer and to receive therefrom the electrical signal corresponding to the reflected acoustic energy; and a housing defining a housing envelope, said housing having an elongated body with first and second ends and a major face intersecting the first and second ends, a head mounted on the first end of said body with a portion extending transversely to the major face and outwardly from the intersection thereof with the first end, and a reflector mounted on the major face, the body having a compartment therein enclosing said electronic circuitry, the head supporting the transducer so that it is positioned to emit and receive acoustic energy in a direction toward the reflector, and the reflector being spaced from said transducer a distance at least half as great as that which acoustic energy travels during the known time interval. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- an electroacoustic transducer adapted to alternately emit a burst of acoustic energy in response to a corresponding electrical drive signal and convert the portion of the burst of acoustic energy reflected back from a remote target to a corresponding electrical signal, said transducer being subject to unavoidable ringing for a known time interval after each emission of a burst of acoustic energy;
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10. A single transducer ultrasonic distance sensor comprising:
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a housing body having first and second ends and a major face extending between the first and second ends, said housing body having a compartment therein; a head on the first end of said housing body, said head having a projecting portion which extends beyond the edge of the first end of said housing body at its intersection with the major face; an electroacoustic transducer mounted in the projecting portion of said head and positioned to transmit and receive acoustic energy in a direction substantially parallel with the major face of said housing body; transmit/receive circuitry within the compartment in said housing body and connected to said electroacoustic transducer, said transmit/receive circuitry being adapted to alternately cause said electroacoustic transducer to transmit a burst of acoustic energy and receive electrical signals resulting from receipt by said electroacoustic transducer of reflections of the burst of acoustic energy from a remote target, said transducer being subject to unavoidable ringing for a known time interval after each transmission of a burst of acoustic energy, whereby the range of a target within a known distance from said electroacoustic transducer corresponding to one half of the known time interval cannot be reliably determined; and a reflector on said housing body near the second end thereof at a distance from the radiating surface on said electroacoustic transducer at least as great as one half of the distance travelled by acoustic energy during the known time interval, said housing body, said head and said reflector defining a housing envelope, said reflector being positioned to intercept at least a portion of the acoustic energy transmitted by said electroacoustic transducer and to reflect the intercepted energy out of the housing envelope. - View Dependent Claims (11, 12, 13, 14)
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Specification