Single piezoelectric transmitter and receiver to detect blood velocities

Abstract

A system for detecting blood velocity within a blood vessel includes a piezoelectric transducer supported on a ceramic substrate. The ceramic substrate supports the piezoelectric transducer at a fixed angle of incidence that is greater than 0° and less than 90°. The ceramic substrate is formed of steatite ceramic and is configured to couple an ultrasonic signal emitted by the transducer to skin underlying the substrate.

What is claimed is: 
     
         1 . A system for detecting blood velocity in a blood vessel, the system comprising:
 a first ceramic substrate having a planar first main surface and a planar second main surface;   a first ultrasonic piezoelectric transducer arranged on the first main surface of the first ceramic substrate; and   a signal control system electrically connected to the first ultrasonic piezoelectric transducer and configured to supply the first ultrasonic piezoelectric transducer with an electrical actuation signal configured to cause the first ultrasonic piezoelectric transducer to emit an ultrasonic signal,   wherein the first main surface of the first ceramic substrate lies substantially in a first plane and the second main surface of the first ceramic substrate lies substantially in a second plane, and   wherein the second main surface is angled with respect to the first main surface of the first ceramic substrate such that the first ultrasonic piezoelectric has an angle of incidence with respect to the second plane that is greater than 0° and less than 90°.   
     
     
         2 . The system of  claim 1 , wherein the first main surface is configured to be placed against skin of a user. 
     
     
         3 . The system of  claim 2 , wherein the substrate is configured to couple the ultrasonic signal to the skin of the user. 
     
     
         4 . The system of  claim 3 , wherein the substrate is formed of steatite ceramic. 
     
     
         5 . The system of  claim 4 , further comprising:
 a second ceramic substrate arranged adjacent to the first ceramic substrate and having a planar first main surface and a planar second main surface; and   a second ultrasonic piezoelectric transducer arranged on the first main surface of the second ceramic substrate,   wherein the second ultrasonic piezoelectric transducer is angled with respect to the second main surface of the second ultrasonic piezoelectric transducer such that the second ultrasonic piezoelectric transducer has the same angle of incidence as the first piezoelectric transducer.   
     
     
         6 . The system of  claim 5 , wherein the first ultrasonic piezoelectric transducer and the second ultrasonic piezoelectric transducer are each elements of a distributed transducer. 
     
     
         7 . The system of  claim 6 , wherein the signal control system electrically is connected to the first ultrasonic piezoelectric transducer and the second ultrasonic piezoelectric transducer and is configured to supply the first ultrasonic piezoelectric transducer and the second ultrasonic piezoelectric transducer with the electrical actuation signal. 
     
     
         8 . The system of  claim 7 , further comprising:
 an isolation layer interposed between the first ceramic substrate and the second ceramic substrate.   
     
     
         9 . A system for detecting blood velocity in a blood vessel, the system comprising:
 a first ceramic substrate having a planar first main surface and a planar second main surface;   a first ultrasonic piezoelectric transducer arranged on the first main surface of the first ceramic substrate; and   a second ceramic having a planar first main surface and a planar second main surface; and   a second ultrasonic piezoelectric transducer arranged on the first main surface of the second ceramic substrate,   wherein the first main surface of the first ceramic substrate lies substantially in a first plane and the second main surface of the first ceramic substrate lies substantially in a second plane,   wherein the second main surface is angled with respect to the first main surface of the first ceramic substrate such that the first ultrasonic piezoelectric has an angle of incidence with respect to the second plane that is greater than 0° and less than 90°,   wherein the first main surface of the second ceramic substrate lies substantially in the first plane and the second main surface of the second ceramic substrate lies substantially in a third plane,   wherein the second main surface of the second ceramic substrate is angled with respect to the first main surface of the second ceramic substrate such that the second ultrasonic piezoelectric has an angle of incidence with respect to the third plane that is greater than 0° and less than 90, and   wherein the first ultrasonic piezoelectric transducer is configured as an ultrasonic transmitter, and the second ultrasonic piezoelectric transducer is configured as an ultrasonic receiver.   
     
     
         10 . The system of  claim 9 , further comprising:
 a signal control system electrically connected to the second ultrasonic piezoelectric transducer and configured to receive electrical output signals from the second ultrasonic piezoelectric transducer,   wherein the signal control system is configured to evaluate the electrical output signals from the second ultrasonic piezoelectric transducer to process the electrical output signals to determine at least one of a location of a blood vessel within a body of a user, a measurement angle for the blood vessel, and a velocity of blood within the blood vessel.   
     
     
         11 . The system of  claim 10 , wherein the signal control system is configured to process the electrical output signals based a Doppler Effect. 
     
     
         12 . The system of  claim 10 , wherein the first ceramic substrate, the first ultrasonic piezoelectric transducer, the second substrate and the second ultrasonic piezoelectric transducer are incorporated into a housing. 
     
     
         13 . The system of  claim 12 , wherein the housing is a handheld portable housing. 
     
     
         14 . The system of  claim 12 , wherein the housing is incorporated into a wearable article which is configured to be worn on a body of the user. 
     
     
         15 . The system of  claim 14 , wherein the first ultrasonic piezoelectric transducer comprises a distributed transducer. 
     
     
         16 . The system of  claim 9 , wherein the first ceramic substrate and the second ceramic substrate are each formed of steatite ceramic. 
     
     
         17 . A method of detecting blood velocity within a blood vessel, the method comprising:
 placing a first ceramic substrate on a planar area of skin;   actuating a first ultrasonic piezoelectric transducer to emit an ultrasonic signal toward the blood vessel, the first ultrasonic piezoelectric transducer being supported on the first ceramic substrate at an angle of incidence with respect to the planar area of skin, the angle of incidence being greater than 0° and less than 90°;   receiving a reflected ultrasonic signal with a second ultrasonic piezoelectric transducer, the second ultrasonic piezoelectric transducer being supported on a second ceramic substrate at the angle of incidence; and   evaluating an electrical signal output by the second ultrasonic piezoelectric to determine at least one of a location of a blood vessel, a measurement angle for the blood vessel, and a velocity of blood within the blood vessel.   
     
     
         18 . The method of  claim 18 , wherein the ultrasonic signal is propagated through the first ceramic substrate to the skin. 
     
     
         19 . The method of  claim 18 , wherein the first ceramic substrate and the second ceramic substrate are formed of steatite ceramic.