Means for reducing minimum sensing distance of an ultrasonic proximity sensor
First Claim
1. An ultrasonic sensor for use in determining the presence of objects in close proximity to the sensor, including objects immediately adjacent the sensor and objects a distance of several times the sensor'"'"'s diameter away, the sensor comprising:
- a transducer for producing an ultrasonic signal mounted within a housing, wherein the transducer has a preselected standoff time while operating at a relatively high preselected frequency, the transducer being directly aligned with an object to be detected and positioned a minimum distance from the nearest possible position of the object to be detected wherein the minimum distance is greater than a distance the ultrasonic signal will travel during one-half of the preselected standoff time;
a power supply for providing energy to the transducer at the preselected frequency such that the transducer is energized by a burst of power suitable for the transducer; and
processing means attached to the transducer for recognizing signals detected by the transducer following the preselected standoff time.
1 Assignment
0 Petitions
Accused Products
Abstract
A rugged ultrasonic sensor is provided which is capable of detecting objects in very close proximity to the sensor. This close proximity detection includes the detection of objects which are immediately adjacent the sensor housing. Such close range operation is achieved by tailoring the transducer to operate at previously undesirable conditions, including low Q and high frequency. Such operating conditions allow the resonating characteristics of the transducer not to interfere with close range operation.
-
Citations
12 Claims
-
1. An ultrasonic sensor for use in determining the presence of objects in close proximity to the sensor, including objects immediately adjacent the sensor and objects a distance of several times the sensor'"'"'s diameter away, the sensor comprising:
-
a transducer for producing an ultrasonic signal mounted within a housing, wherein the transducer has a preselected standoff time while operating at a relatively high preselected frequency, the transducer being directly aligned with an object to be detected and positioned a minimum distance from the nearest possible position of the object to be detected wherein the minimum distance is greater than a distance the ultrasonic signal will travel during one-half of the preselected standoff time; a power supply for providing energy to the transducer at the preselected frequency such that the transducer is energized by a burst of power suitable for the transducer; and processing means attached to the transducer for recognizing signals detected by the transducer following the preselected standoff time. - View Dependent Claims (2, 3, 4, 5)
-
-
6. An ultrasonic sensor for use in determining the presence of objects in close proximity to the sensor, including objects immediately adjacent the sensor and objects a distance of several times the sensor'"'"'s diameter away, the sensor comprising:
-
a piezoceramic transducer for producing an ultrasonic signal at an active surface when energized, and for detecting ultrasonic signals at the active surface when not energized, wherein the piezoceramic transducer has a preselected ringing characteristic which includes a preselected standoff time while operating at a relatively high predetermined frequency; a housing for holding the piezoceramic transducer such that the active surface of the transducer is directly aligned with the object to be detected and is recessed a minimum distance in relation to a edge surface of the housing wherein the minimum distance is greater than a distance the ultrasonic signal will travel during one-half of the preselected standoff time; a power supply attached to the piezoceramic transducer for energizing the piezoceramic sensor with a burst of energy suitable for the transducer at the predetermined frequency; and sensing means attached to the piezoceramic transducer for determining when the piezoceramic transducer has detected an ultrasonic signal, wherein the burst of energy and the preselected ringing characteristics are related to allow detection of objects at the edge surface of the housing. - View Dependent Claims (7, 8, 9)
-
-
10. An ultrasonic sensor for use in determining the presence of objects in close proximity to the sensor, including objects immediately adjacent the sensor and objects a distance of several times the sensor'"'"'s diameter away, the sensor comprising:
-
a sensor housing having an edge surface; a piezoceramic transducer mounted within the sensor housing, the piezoceramic transducer having an active surface for producing ultrasonic signals in response to electrical excitation and for producing detection signals in response to external ultrasonic signals, the active surface being positioned within the housing such that a recess of a minimum distance exists between the edge surface and the active surface the piezoceramic transducer having a preselected ringing characteristic which is dependent upon the electrical characteristics of the transducer which includes a preselected standoff time while operating at a relatively high predetermined frequency, wherein the minimum distance is greater than a distance the ultrasonic signal will travel during one-half of the preselected standoff time; a power supply attached to the piezoceramic transducer for providing electrical excitation for a predetermined excitation time; and a signal detector attached to the piezoceramic transducer for determining the presence of detection signals, wherein the sensor is capable of detecting the detection signals a preselected standoff time after the predetermined excitation time. - View Dependent Claims (11, 12)
-
Specification