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US-12622673-B2 - Ultrasonic probe

US12622673B2US 12622673 B2US12622673 B2US 12622673B2US-12622673-B2

Abstract

An ultrasonic probe that comprises an ultrasonic transducer that includes an array of transducer elements and an attenuation material is provided. The attenuation material comprises a polymer composition that includes a liquid crystalline polymer and a thermally conductive particulate material. The liquid crystalline polymer has a melting temperature of about 270° C. or more and a melt viscosity of about 500 Pa-s or less as determined at a temperature of 45° C. above the melting temperature and shear rate of 400 s −1 in accordance with ISO Test No. 11443:2005, and the polymer composition also has a through-plane conductivity of about 0.2 W/m-K or more.

Inventors

  • Darin Grinsteinner
  • Young Shin Kim

Assignees

  • TICONA LLC

Dates

Publication Date
20260512
Application Date
20200707

Claims (20)

  1. 1 . An ultrasonic probe comprising: an ultrasonic transducer that includes an array of transducer elements capable of converting electrical energy to ultrasonic acoustic energy for emission towards a region of interest; and an attenuation material that is capable of inhibiting the return of the ultrasonic acoustic energy back towards the ultrasonic transducer after emission towards the region of interest, wherein the attenuation material comprises a polymer composition that includes a liquid crystalline polymer and a thermally conductive particulate material, wherein the liquid crystalline polymer comprises repeating units derived from naphthenic hydroxycarboxylic acids and/or naphthenic dicarboxylic acids has a melting temperature of about 270° C. or more and a melt viscosity of about 500 Pa-s or less as determined at a temperature of 45° C. above the melting temperature and shear rate of 400 s −1 in accordance with ISO Test No. 11443:2005, and further wherein the polymer composition has a through-plane conductivity of 0.4 W/m-K or more.
  2. 2 . The ultrasonic probe of claim 1 , wherein the liquid crystalline polymer comprises repeating units (1) to (3): wherein, Ra, Rb, and Rf are independently alkynyl, alkyl, alkenyl, aryl, heteroaryl, cycloalkyl, heterocyclyl, halo, or haloalkyl; and l, m, and q are independently an integer from 0 to 4.
  3. 3 . The ultrasonic probe of claim 2 , wherein the repeating units (1) are derived from 4-hydroxybenzoic acid, the repeating units (2) are derived from hydroquinone, and the repeating units (3) are from isophthalic acid.
  4. 4 . The ultrasonic probe of claim 2 , wherein the repeating units (1) constitute from about 40 mole % to about 80 mole % of the polymer, and wherein the repeating units (2) and (3) each constitute from about 1 mole % to about 20 mole % of the polymer.
  5. 5 . The ultrasonic probe of claim 2 , wherein the molar ratio of repeating units (2) to the repeating units (3) is from about 0.8 to about 2.
  6. 6 . The ultrasonic probe of claim 2 , wherein the liquid crystalline polymer further comprises repeating units (4) and (5): wherein, Rc, Rd, and Re are independently alkynyl, alkyl, alkenyl, aryl, heteroaryl, cycloalkyl, heterocyclyl, halo, or haloalkyl; and n, o, and p are independently an integer from 0 to 4.
  7. 7 . The ultrasonic probe of claim 6 , wherein the repeating units (4) are derived from 4,4′-biphenol and the repeating units (5) are derived from terephthalic acid.
  8. 8 . The ultrasonic probe of claim 7 , wherein the repeating units (4) and (5) each constitute from about 5 mole % to about 30 mole % of the polymer.
  9. 9 . The ultrasonic probe of claim 7 , wherein the molar ratio of repeating units (5) to the repeating units (4) is from about 0.8 to about 2.
  10. 10 . The ultrasonic probe of claim 1 , wherein the thermally conductive particulate material has an average size of about 100 to about 2,000 micrometers.
  11. 11 . The ultrasonic probe of claim 1 , wherein the thermally conductive particulate material has an intrinsic thermal conductivity of about 50 W/m-K or more.
  12. 12 . The ultrasonic probe of claim 1 , wherein the thermally conductive particulate material includes boron nitride, aluminum nitride, magnesium silicon nitride, graphite, silicon carbide, carbon nanotubes, carbon black, metal oxide, metallic powder, or a combination thereof.
  13. 13 . The ultrasonic probe of claim 1 , wherein the thermally conductive particulate material is present in the polymer composition in an amount of from about 50 to about 200 parts per 100 parts of the liquid crystalline polymer.
  14. 14 . The ultrasonic probe of claim 1 , wherein the thermally conductive particulate material constitutes from about 25 wt. % to about 70 wt. % of the polymer composition and liquid crystalline polymers constitute from about 30 wt. % to about 75 wt. % of the polymer composition.
  15. 15 . The ultrasonic probe of claim 1 , wherein the polymer composition has a through-plane conductivity of from about 4 to about 15 W/m-K.
  16. 16 . The ultrasonic probe of claim 1 , wherein the ultrasonic probe is connected to an ultrasound imaging apparatus that is configured to send the electrical energy to the ultrasonic transducer.
  17. 17 . The ultrasonic probe of claim 1 , wherein the attenuation material is electrically connected to a surface of the ultrasonic transducer.
  18. 18 . The ultrasonic probe of claim 1 , further comprising a housing that encloses the ultrasonic transducer.
  19. 19 . The ultrasonic probe of claim 18 , wherein at least a portion of the housing is formed from the attenuation material.
  20. 20 . The ultrasonic probe of claim 19 , wherein the attenuation material is positioned on a surface of the housing.

Description

RELATED APPLICATION The present application claims priority to U.S. Provisional Application Ser. No. 62/875,025, filed on Jul. 17, 2019, which is incorporated herein in its entirety by reference thereto. BACKGROUND OF THE INVENTION Ultrasound imaging probes continue to enjoy widespread use in the medical field. By way of example, ultrasound probes are utilized for a wide variety of external, laparoscopic, endoscopic and intravascular imaging applications. The ultrasound images provided by imaging probes may, for example, be used for diagnostic purposes. The probes typically include a plurality of parallel piezoelectric transducer elements arranged along a longitudinal axis, with each element interconnected to a pair of electrodes. An electronic circuit excites the transducer elements causing them to emit ultrasonic energy. The transducer elements then convert the received ultrasonic energy into electrical signals, which may then be processed and used to generate images. Typically, the transducers include an active layer of a piezoelectric material with an acoustic face from which acoustic signals are emitted. An acoustic attenuation member is also generally disposed on the back surface of the active layer to dampen undesirable acoustic signals (e.g., signals that may emanate from and be reflected back to the rear face of the transducer), which would otherwise interfere with the acoustic signals received at the acoustic face. Unfortunately, due to the increased complexity of most probe designs, power consumption is increased, which in turn leads to an increase in the amount of heat that is produced by the probe. This increased production of heat can be a problem due to the fact most acoustic attenuation members are not highly heat sensitive. Over time, this can ultimately lead to a malfunction of the camera sensor. As such, a need exists for an improved ultrasonic probe having a higher degree of heat sensitivity. SUMMARY OF THE INVENTION In accordance with one embodiment of the present invention, an ultrasonic probe is disclosed that comprises an ultrasonic transducer that includes an array of transducer elements capable of converting electrical energy to ultrasonic acoustic energy for emission towards a region of interest and an attenuation material that is capable of inhibiting the return of the ultrasonic acoustic energy back towards the ultrasonic transducer after emission towards the region of interest. The attenuation material comprises a polymer composition that includes a liquid crystalline polymer and a thermally conductive particulate material. The liquid crystalline polymer has a melting temperature of about 270° C. or more and a melt viscosity of about 500 Pa-s or less as determined at a temperature of 45° C. above the melting temperature and shear rate of 400 s−1 in accordance with ISO Test No. 11443:2005, and the polymer composition also has a through-plane conductivity of about 0.2 W/m-K or more. Other features and aspects of the present invention are set forth in greater detail below. BRIEF DESCRIPTION OF THE FIGURES A full and enabling disclosure of the present invention, including the best mode thereof to one skilled in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which: FIG. 1 is a schematic diagram of an embodiment of an ultrasound probe and a region of interest; FIG. 2 is an isometric view of an embodiment of an ultrasound probe of the present invention; and FIG. 3 is a schematic view of a portion of the ultrasonic transducer of FIG. 2. DETAILED DESCRIPTION It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention. Generally speaking, the present invention is directed to an ultrasonic probe that contains an ultrasonic transducer and an attenuation material that is capable of attenuating acoustic energy incident upon the material, such as energy having a frequency between 100 kHz and 100 MHz. The attenuation material includes a polymer composition, which contains a liquid crystalline polymer and thermally conductive particulate material. By selectively controlling the nature of the components in the polymer composition and their relative concentration, the resulting composition is capable of serving as an effective acoustic attenuation material, but also exhibit good thermal properties that allow for heat transfer so that “hot spots” can be quickly eliminated and the overall temperature of the part can be lowered during use. More particularly, the composition exhibits a through-plane thermal conductivity of about 0.2 W/m-K or more, in some embodiments about 0.4 W/m-K or more, in some embodiments about 0.5 W/m-K or more, in some embodiments from about 1 to about 25 W/m-K, in some embodiments from about 2 to about 20 W/m-k, and in some embodiments, from a