Method of making a piezoelectric transducer having protuberances for transmitting acoustic energy
First Claim
1. A method of forming protuberances in piezoelectric material for an acoustic device comprising:
- providing a substrate having a plurality of perforations of a given dimension formed therein;
forming a laminate comprising a film of polymer piezoelectric material sandwiched between a first electrode layer on a top surface and a second electrode layer on a bottom surface;
securing the laminate to the substrate to form a composite assembly; and
treating the composite assembly to form protuberances in the film at the locations of the perforations.
8 Assignments
0 Petitions
Accused Products
Abstract
A method of forming an ultrasound transducer having thermoformed protuberances comprises providing a substrate having a plurality of perforations of a given dimension. The perforations or apertures are formed in the substrate and operate to determine the resonance frequency associated with the transducer. A film of polymeric material capable of showing piezoelectric properties when strained in its plane and electrically biassed by a field applied in a direction normal to its faces, is then laminated onto the substrate. The film is heated to a given temperature and a pressure differential is applied between the top and bottom surfaces of the film for a sufficient time to form protuberances in the film through the apertures in the substrate. The film is then cooled to a given ambient temperature while maintaining a pressure differential between the top and bottom surfaces of the film for a sufficient time until the ambient temperature is reached so as to cause the protuberances to maintain a substantially permanent curvature.
57 Citations
23 Claims
-
1. A method of forming protuberances in piezoelectric material for an acoustic device comprising:
-
providing a substrate having a plurality of perforations of a given dimension formed therein;
forming a laminate comprising a film of polymer piezoelectric material sandwiched between a first electrode layer on a top surface and a second electrode layer on a bottom surface;
securing the laminate to the substrate to form a composite assembly; and
treating the composite assembly to form protuberances in the film at the locations of the perforations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
securing the bottom surface of the composite assembly to a vacuum chamber;
placing the composite assembly into a temperature chamber; and
activating a vacuum pump to cause a pressure differential between the top and bottom surfaces of the composite assembly (while applying heat to the assembly through the temperature chamber for a predetermined time interval) sufficient to form the protuberances in the film; and
after the predetermined time interval cooling the composite assembly to a given temperature while maintaining the pressure differential until the given temperature is reached to cause each of the protuberances to maintain a substantially permanent curvature.
-
-
7. The method according to claim 1, wherein the substrate comprises a metal.
-
8. The method according to claim 1, wherein the substrate comprises a printed circuit board.
-
9. The method according to claim 1, wherein the substrate comprises a plastic.
-
10. The method according to claim 1, wherein the perforations in the substrate are patterned in a periodic manner.
-
11. The method according to claim 10, wherein the perforations have a shape selected from the group consisting of a circle, rectangle and rhombus.
-
12. The method according to claim 1, wherein the first and second electrode layers are formed of silver ink.
-
13. The method according to claim 1, wherein the first and second electrode layers are formed of metal.
-
14. The method according to claim 1, wherein the step of securing the laminate to the substrate comprises applying a layer of adhesive material to the substrate.
-
15. The method according to claim 14, wherein the adhesive material is an epoxy.
-
16. The method according to claim 1, wherein the step of treating further comprises disposing a top plate layer at the top surface of the film and a bottom plate layer at a bottom surface of the substrate;
-
disposing a layer of pliable material between the top plate layer and top surface of the film; and
compressing the top and bottom plate layers toward one another to cause the layer of pliable material to forcibly engage the film to cause deformation of portions of the film through the perforations in the substrate thereby forming the protuberances.
-
-
17. The method according to claim 1, wherein the ultrasound transducer is an omnidirectional transducer.
-
18. The method according to claim 1, wherein the transducer is a substantially flat transducer.
-
19. A method of forming a transducer having protuberances comprising:
-
providing a substrate including a plurality of perforations each of a given dimension formed therein and indicative of a resonance frequency associated with the transducer;
laminating a film of polymeric material onto the substrate, the polymeric material capable of exhibiting piezoelectric properties;
disposing a top plate layer at a top surface of the film and a bottom plate layer at a bottom surface of the substrate;
disposing a layer of pliable material between the top plate layer and the top surface of the film;
compressing the top and bottom plate layers toward each other to cause the layer of pliable material to forcibly engage the film to cause deformation of portions of the film through the perforations in the substrate thereby, forming the protuberances. - View Dependent Claims (20, 21, 22)
heating the film simultaneously with the compression step for a predetermined period; and
after the predetermined period, cooling the film to an ambient temperature to cause the protuberances to maintain a substantially permanent curvature.
-
-
23. A method of forming an ultrasound transducer having thermoformed protuberances comprising:
-
providing a substrate having a plurality of perforations each of a given dimension formed therein;
laminating a film of polymeric material onto the substrate, the polymeric material capable of exhibiting piezoelectric properties when strained in its plane and electrically biased by a field applied in a direction normal to its faces;
heating the film to a given temperature and applying a pressure differential between top and bottom surfaces of the film to form protuberances in the film through the perforations in the substrate for a predetermined time interval; and
cooling the heated film to a given temperature while maintaining the pressure differential until the given temperature is reached to cause the protuberances to maintain a substantially permanent curvature.
-
Specification