Ultrasound transducer with acoustic absorber structure
Described are acoustic absorber materials with high acoustic attenuation and high thermal conductivity comprising an inorganic, porous foam and an absorbing material within at least a portion of the pores of the foam, ultrasound transducers and devices including the same, as well as methods of making the materials.
1. An ultrasound probe comprising:
(a) a printed circuit board (PCB);
(b) an application-specific integrated circuit (ASIC) coupled to the PCB directly above the PCB;
(c) a piezoelectric micromachined ultrasound transducer (pMUT) coupled to the ASIC; and
(d) a thermally conductive acoustic absorber mounted between the PCB and a heatsink, the thermally conductive acoustic absorber comprising:
i) an acoustic absorber comprising a porous copper foam having a plurality of pores; and
(ii) an acoustic absorbing material comprising an epoxy and tungsten particle mixture within at least a portion of the plurality of pores of the porous copper foam.
2. The ultrasound probe of claim 1 , wherein the pores form a continuous network.
3. The ultrasound probe of claim 1 , wherein the pores form a semi-continuous network.
4. The ultrasound probe of claim 1 , wherein the pores are partially closed.
5. The ultrasound probe of claim 1 , wherein the pores are closed.
6. The ultrasound probe of claim 1 , wherein the porous foam has a pore density of about 2 pores/cm to about 100 pores/cm.
7. The ultrasound probe of claim 1 , wherein the porous foam has a porosity of about 60% to about 98%.
8. The ultrasound probe of claim 1 , wherein the porous foam comprises a cellular material, a sponge material, or both.
9. The ultrasound probe of claim 1 , wherein the porous foam comprises an inorganic material with a porous foam structure.
10. The ultrasound probe of claim 9 , wherein the inorganic material comprises a metal, a metal alloy, a ceramic, a semiconductor, a composite, or any combination thereof.
11. The ultrasound probe of claim 10 , wherein the inorganic material is at least partially crystalline.
12. The ultrasound probe of claim 1 , further comprising an acoustic reflector mounted between the PCB and the acoustic absorber to reflect at least a portion of acoustic energy back toward the ultrasound transducer before any remaining acoustic energy reaches the acoustic absorber.
13. The ultrasound probe of claim 1 , wherein the thermally conductive acoustic absorber is directly bonded to the PCB and the heatsink.
14. The ultrasound probe of claim 1 , wherein the acoustic absorber reduces reflections of acoustic energy off the heatsink and wherein a thermal conductivity of the acoustic absorber is sufficient to act as a heatsink.
15. The ultrasound probe of claim 1 , wherein the pMUT is coupled to the ASIC through a plurality of pillars.
16. An ultrasound probe comprising:
(a) a printed circuit board (PCB);
(b) an application-specific integrated circuit (ASIC) coupled to the PCB;
(c) a piezoelectric micromachined ultrasound transducer (pMUT) coupled to the ASIC; and
(d) a thermally conductive acoustic absorber mounted between the PCB and the ASIC, the thermally conductive acoustic absorber comprising:
(i) an acoustic absorber comprising a porous copper foam having a plurality of pores; and
(ii) an acoustic absorbing material comprising an epoxy and tungsten particle mixture within at least a portion of the plurality of pores of the porous copper foam.
17. The ultrasound probe of claim 16 , wherein the pMUT is coupled to the ASIC through a plurality of pillars.
18. An ultrasound probe comprising:
(a) a printed circuit board (PCB);
(b) an application-specific integrated circuit (ASIC) coupled to the PCB;
(c) a micromachined ultrasound transducer (MUT) coupled to the ASIC; and
(d) a thermally conductive acoustic absorber comprising:
(i) a porous foam having a plurality of pores that form a semi-continuous network; and
(ii) an acoustic absorbing material within at least a portion of the plurality of pores of the porous foam.
19. The ultrasound probe of claim 18 , wherein the porous foam comprises a copper foam.
20. The ultrasound probe of claim 19 , wherein the acoustic absorbing material comprises an epoxy and an inorganic filler.
21. The ultrasound probe of claim 20 , wherein the inorganic filler comprises tungsten.
22. The ultrasound probe of claim 18 , wherein the porous foam comprises an inorganic material with a porous foam structure.
23. The ultrasound probe of claim 18 , wherein the MUT comprises a piezoelectric micromachined ultrasound transducer.
24. The ultrasound probe of claim 18 , wherein the MUT is coupled to the ASIC through a plurality of pillars.
25. The ultrasound probe of claim 18 , wherein the PCB and the MUT are coupled to different sides of the ASIC.