# US 5,345,139 A · Electrostrictive ultrasonic probe having expanded operating temperature range > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,345,139 A - Document ID: US5345139A - Status: Granted - Kind: A - Application number: 08/113,450 - Filed: 1993-08-27 - Granted: 1994-09-06 - Earliest claimed: 1993-08-27 - Assignees: Hewlett-Packard Company - Inventors: Turuvekere R. Gururaja; Joseph Fielding; Thomas R. Shrout; Sei-Joo Jang - Web page: https://patentgrep.com/patent/US5345139A ## CPC - H10N 30/853: Ceramic compositions - B06B 1/06: operating with piezoelectric effect or with electrostriction (piezoelectric or electrostrictive devices per se H10N30/00) - H04R 17/08: signals being recorded or played back by vibration of a stylus in two orthogonal directions simultaneously - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR - B06B: METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, {e.g.} FOR PERFORMING MECHANICAL WORK IN GENERAL (for particular applications, see the relevant subclasses, e.g. B07B1/40, B23Q17/12, B24B31/06; measurement of mechanical vibrations G01H; in direction finding, locating, distance or velocity measuring G01S; {generating seismic energy G01V1/02}; control of mechanical vibrations in general G05D; sound-producing devices, e.g. bells, sirens, whistles G10K, {e.g. methods or devices for transmitting, conducting, or directing sound in general G10K11/00}; generation of electrical oscillations H03B; electromechanical resonators in general H03H; electromechanical transducers {for communication techniques, e.g. microphones, speakers} H04R) - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) ## Abstract An ultrasonic electrostrictive transducer for transmitting and receiving ultrasonic energy and having an expanded operating temperature range, preferably about room temperature. The transducers may be made from PMN-PT solid solutions having select mole percentages of PT and being doped with La, whereby the operating temperature range about a given operating temperature may be effectively doubled. ## Claims ### Claim 1 In an ultrasonic probe having an electrostrictive transducer for transmitting and receiving ultrasonic energy, and having electrical contacts attached to the transducer for connection to a source that selectively applies an electric field to the transducer, the improvement comprising: the transducer being fabricated from a material comprising a solid solution of lead magnesium niobate PMN and lead titanate PT and being doped with lanthanum La according to the formula: Pb.sub.1-( 3/2 )y La.sub.y .quadrature..sub.y/2 [(Mg.sub.1/3 Nb.sub.2/3).sub.1-x Ti.sub.x ]O.sub.3 (I) wherein x and y are on the order of 10.ltoreq.x.ltoreq.30 mole % 0.5.ltoreq.y.ltoreq.3 mole %. and .quadrature. represents a vacancy at the Pb site, wherein the transducer provides an expanded operating temperature range. ### Claim 2 (depends on 1) The probe of claim 1, wherein the transducer provides an expanded operating temperature range around room temperature and includes a solid solution selected from the group consisting of: (a) y on the order of 1 mole % and x on the order of 12.5-17.5 mole %; (b) y on the order of 2 mole % and x on the order of 17-22 mole %; and (c) y on the order of 3 mole % and x on the order of 23-28 mole %. ### Claim 3 (depends on 2) The probe of claim 2, wherein x is on the order of 15% and y is on the order of 1%. ### Claim 4 (depends on 2) The probe of claim 2, wherein x is on the order of 17.5% and y is on the order of 1%. ### Claim 5 (depends on 2) The probe of claim 2, wherein x is on the order of 13.5% and y is on the order of 1%. ### Claim 6 (depends on 1) The probe of claim 1, wherein the transducer comprises a composite of polymer and the PMN:PT:La solid solution. ### Claim 7 An electrostrictive transducer for transmitting and receiving ultrasonic energy, comprising: a backing layer; at least one electrostrictive transducer element disposed on the backing layer; and electrical contacts attached to the transducer element and connectable to a source for selectively producing electric fields in the transducer element, wherein the transducer is fabricated from a material comprising a solid solution of lead magnesium niobate PMN and lead titanate PT and is doped with lanthanum La according to the formula: Pb.sub.1-(3/2)y La.sub.y .quadrature..sub.y/2 [(Mg.sub.1/3 Nb.sub.2/3).sub.1-x Ti.sub.x ]O.sub.3 (I) wherein x and y are on the order of 1.ltoreq. x.ltoreq.30 mole % 0.5.fwdarw.y.ltoreq.3 mole %. and .quadrature. represents a vacancy at the Pb site, wherein the transducer provides an expanded operating temperature range. ### Claim 8 (depends on 7) The transducer of claim 7, wherein the transducer provides an expanded operating temperature range around room temperature and includes a solid solution selected from the group consisting of: (a) y on the order of 1 mole % and x on the order of 12.5-17.5 mole %; (b) y on the order of 2 mole % and x on the order of 17-22 mole %; and (c) y on the order of 3 mole % and x on the order of 23-28 mole %. ### Claim 9 (depends on 8) The transducer of claim 8, wherein x is on the order of 13.5 to 17.5 mole % and y is on the order of 1 mole %. ### Claim 10 A method of expanding the operating temperature range of an ultrasonic probe comprising: providing an electrostrictive transducer for transmitting and receiving ultrasonic energy, and electrical contacts attached to the transducer for connection to a source that selectively applies an electric field to the transducer, wherein the transducer comprises a solid solution of lead magnesium niobate PMN and lead titanate PT; and selecting the relative mole % of PMN and PT and doping with a mole % lanthanum La according to the formula: Pb.sub.1-(3/2)y La.sub.y .quadrature..sub.y/2 [(Mg.sub.1/3 Nb.sub.2/3).sub.1-x Ti.sub.x ]O.sub.3 (I) wherein x and y are on the order of 10.ltoreq.x.ltoreq.30 mole % 0.5.ltoreq.y.ltoreq.3 mole %. and .quadrature. represents a vacancy at the Pb site, in order to expand the operating temperature range. ### Claim 11 (depends on 10) The method of claim 10, wherein the transducer provides an expanded operating temperature range around room temperature and includes solid solutions selected from the group consisting of: (a) y on the order of 1 mole % and x on the order of 12.5-17.5 mole %; (b) y on the order of 2 mole % and x on the order of 17-22 mole %; and (c) y on the order of 3 mole % and x on the order of 23-28 mole %. ### Claim 12 (depends on 11) The method of claim 11, wherein x is on the order of 13.5 to 17.5 mole % and y is on the order of 1 mole %.