Piezoelectric element, ultrasonic transducer, and method of manufacturing same

Abstract

This piezoelectric element includes: an upper surface electrode and a lower surface electrode that form an external electrode; an internal electrode; a lower surface electrode connection body that includes a lower surface electrode terminal adjacent to the upper surface electrode across a lower surface electrode-side gap; an internal electrode connection body including an internal electrode terminal adjacent to the upper surface electrode across an internal electrode-side gap; and an insulating cover body integrally covering at least a portion of the internal electrode terminal, an internal electrode terminal facing region of the upper surface electrode that faces the internal electrode terminal across the internal electrode-side gap, and a region of the internal electrode-side gap that is sandwiched by the internal electrode terminal and the internal electrode terminal facing region. The insulating cover body is provided with an internal electrode opening that exposes at least a portion of the internal electrode terminal while not exposing the internal electrode terminal facing region.

Description

Piezoelectric element, ultrasonic transducer and manufacturing method thereof

[0001] The present invention relates to a piezoelectric element, an ultrasonic transducer including a piezoelectric element and a wiring body having first and second wirings electrically connected to the external electrode and internal electrode of the piezoelectric element, respectively, and a method for manufacturing an ultrasonic transducer.

[0002] A proposed laminated piezoelectric element includes a piezoelectric element body made of a piezoelectric material, an upper electrode and a lower electrode provided on the upper end surface and the lower end surface, respectively, of the piezoelectric element body, an internal electrode that divides the piezoelectric element body into a first piezoelectric portion on the upper side and a second piezoelectric portion on the lower side in the thickness direction, a lower electrode connector that is provided on the upper end surface of the piezoelectric element body with a base end side electrically connected to the lower electrode and a tip end side with a lower electrode side gap between it and the upper electrode, thereby forming a lower electrode terminal, and an internal electrode connector that is provided on the upper end surface of the piezoelectric element body with a base end side electrically connected to the internal electrode and a tip end side with an internal electrode side gap between it and the upper electrode, thereby forming an internal electrode terminal (see Patent Document 1 below).

[0003] A laminated piezoelectric element having such a configuration is useful in that electrical connection of corresponding wiring can be made from the upper end surface on one side in the thickness direction to both the upper electrode and the lower electrode that form the external electrode, as well as to all of the internal electrodes.

[0004] That is, by providing a first conductive adhesive across both the lower electrode terminal and the lower electrode terminal opposing region of the upper electrode that faces the lower electrode terminal via the lower electrode side gap, and by joining a first wiring that corresponds to the first conductive adhesive, the first wiring can be electrically connected to both the upper electrode and the lower electrode at the upper end surface of the piezoelectric element; further, by providing a second conductive adhesive on the internal electrode terminal and joining a second wiring that corresponds to the second conductive adhesive, the second wiring can be electrically connected to the internal electrode at the upper end surface of the piezoelectric element.

[0005] The piezoelectric element converts the voltage applied between the external electrode and the internal electrode into flexural vibration, or converts the propagated vibration into a voltage between the first and second electrodes. In order to improve the conversion efficiency between voltage and flexural vibration, it is necessary to increase the opposing area between the upper electrode and the internal electrode, and the opposing area between the internal electrode and the lower electrode as much as possible.

[0006] However, in order to maximize the opposing area between the upper surface electrode and the internal electrode, it is necessary to maximize the area of ​​the upper surface electrode itself, which gives rise to the following problems.

[0007] In other words, the expansion of the area of ​​the upper surface electrode leads to a narrowing of the gap on the internal electrode side, and the risk of the second conductive adhesive coming into contact with the upper surface electrode increases due to variations in the amount and position of the second conductive adhesive applied to the internal electrode terminal, which leads to a decrease in yield due to a short circuit between the external electrode (the upper electrode) and the internal electrode, or a decrease in the efficiency of the application of the second conductive adhesive.

[0008] Furthermore, narrowing the gap on the internal electrode side may cause ion migration and lead to short circuit defects under the environmental conditions in which the piezoelectric element is used, such as high temperature and humidity, even if the second conductive adhesive does not come into contact with the upper electrode during the application process.

[0009] Patent No. 6776481

[0010] The present invention has been made in view of the above-described conventional technology, and has as its first object to provide a multi-layer piezoelectric element in which external electrodes including upper surface electrodes and lower surface electrodes and internal electrodes can be electrically connected to their corresponding wiring at the upper end surface on one side in the thickness direction, and which can effectively prevent short circuits between the external electrodes and internal electrodes while improving the conversion efficiency between voltage and flexural vibration.

[0011] A second object of the present invention is to provide an ultrasonic transducer equipped with a stacked piezoelectric element that can effectively prevent short circuits between the external and internal electrodes while improving the conversion efficiency between voltage and flexural vibration.

[0012] A third object of the present invention is to provide an efficient method for manufacturing the ultrasonic transducer.

[0013] In order to achieve the first object, a first aspect of the present invention provides a piezoelectric element body made of a piezoelectric material, an upper surface electrode and a lower surface electrode provided on the upper end surface and the lower end surface of the piezoelectric element body, respectively, and forming external electrodes, an internal electrode dividing the piezoelectric element body into upper and lower portions in the thickness direction, a lower surface electrode connector provided on the upper end surface of the piezoelectric element body with a base end side electrically connected to the lower surface electrode and a tip end side with a lower surface electrode side gap between it and the upper surface electrode, forming a lower surface electrode terminal, and a lower surface electrode connector provided on the upper end surface of the piezoelectric element body with a base end side electrically connected to the internal electrode and a tip end side with an internal electrode side gap between it and the upper surface electrode. and an insulating cover body that integrally covers at least a portion of the internal electrode terminal, an internal electrode terminal facing region of the upper surface electrode that faces the internal electrode terminal across the internal electrode side gap, and a region of the internal electrode side gap that is sandwiched between the internal electrode terminal and the internal electrode terminal facing region, wherein the insulating cover body is provided with an internal electrode opening that exposes at least a portion of the internal electrode terminal but does not expose the internal electrode terminal facing region.

[0014] According to the multi-layer piezoelectric element of the first aspect of the present invention, electrical connection between the external electrodes, including the upper surface electrodes and the lower surface electrodes, and the corresponding wiring, as well as between the internal electrodes and the corresponding wiring, can be made on the upper end surface on one side in the thickness direction of the piezoelectric element, and further, short circuits between the upper surface electrodes and the internal electrodes can be effectively prevented while improving the conversion efficiency of voltage and flexural vibration by enlarging the upper surface electrodes as much as possible.

[0015] In the first aspect, the internal electrode opening may be configured to expose a region of the internal electrode gap adjacent to the exposed region of the internal electrode terminal. Alternatively, the internal electrode opening may be configured not to expose the internal electrode gap.

[0016] In a first embodiment of the first aspect, the insulating cover is configured to integrally cover at least a portion of the lower-surface electrode terminal, a lower-surface electrode terminal-facing region of the upper-surface electrode that faces the lower-surface electrode terminal across the lower-surface electrode-side gap, and a region of the lower-surface electrode-side gap that is sandwiched between the lower-surface electrode terminal and the lower-surface electrode terminal-facing region. In this case, in addition to the internal electrode opening, the insulating cover is provided with an external electrode opening that integrally exposes at least a portion of the lower-surface electrode terminal and at least a portion of the upper-surface electrode.

[0017] In the first form of the first aspect, for example, the insulating cover body may be configured to cover the entire upper end surface of the piezoelectric element body in a plan view, or alternatively, the insulating cover body may be configured to cover a portion of the upper end surface of the piezoelectric element body in a plan view.

[0018] In order to achieve the second object, a second aspect of the present invention provides a semiconductor device comprising: a rigid substrate having a plurality of openings penetrating between an upper surface and a lower surface; a flexible resin film fixed to the upper surface of the substrate so as to cover the plurality of openings; a lower sealing plate having a central opening large enough to surround all of the plurality of openings in a plan view, the lower sealing plate being fixed to the upper surface of the flexible resin film so that the central opening surrounds all of the plurality of openings; a plurality of piezoelectric elements arranged on the upper surface of the flexible resin film within the central opening so as to overlap with the plurality of openings in a plan view; The piezoelectric element includes an insulating resin material that fixes a plurality of piezoelectric elements at their respective positions, and a wiring body having first and second wiring and fixed to the upper surface of the lower sealing plate, the piezoelectric element comprising a piezoelectric element body formed from a piezoelectric material, an upper surface electrode and a lower surface electrode that are provided on the upper end surface and the lower end surface of the piezoelectric element body, respectively, and that form external electrodes, an internal electrode that divides the piezoelectric element body into upper and lower parts in the thickness direction, and a base end side that is electrically connected to the lower surface electrode and a tip end side that is provided on the upper end surface of the piezoelectric element body with a lower surface electrode side gap existing between the base end side and the upper surface electrode. and an internal electrode connector, the base end of which is electrically connected to the internal electrode and the tip end of which is provided on the upper end surface of the piezoelectric element body with an internal electrode-side gap between it and the upper electrode, to form an internal electrode terminal; the insulating resin material is interposed between the lower end surfaces of the plurality of piezoelectric elements and the flexible resin film, and is provided so as to cover the outer side surfaces and upper end surfaces of the plurality of piezoelectric elements; and a portion of the insulating resin material that covers the upper end surfaces of the piezoelectric elements and forms an insulating cover body is provided with the lower electrode terminal. and at least a part of the upper electrode, and an internal electrode opening that exposes at least a part of the internal electrode terminal but does not expose the internal electrode terminal facing region, wherein the first wiring is electrically connected to the lower electrode terminal and the upper electrode exposed by the external electrode opening via a first conductive bonding member, and the second wiring is electrically connected to the internal electrode terminal exposed by the internal electrode opening via a second conductive bonding member.

[0019] In a first embodiment of the second aspect, the insulating resin material includes a first insulating resin material that fixes the lower end surfaces of the plurality of piezoelectric elements to the flexible resin film, and a second insulating resin material that covers the outer side surfaces and upper end surfaces of the plurality of piezoelectric elements. In a second embodiment of the second aspect, the insulating resin material is a single material.

[0020] In the second aspect, the lower sealing plate preferably has partition walls that divide the central opening into a plurality of openings each large enough to surround one of the plurality of piezoelectric elements.

[0021] In the second aspect, the wiring body has an insulating base layer that supports the first and second wirings, and an insulating cover layer that covers at least a portion of the first and second wirings from the side opposite the base layer, and the base layer and the cover layer have a plurality of piezoelectric element overlapping portions that partially overlap each of the plurality of piezoelectric elements in a planar view, and a tip portion that holds the plurality of piezoelectric element overlapping portions together.

[0022] a piezoelectric element overlapping portion of the base layer and the cover layer, which is located on the side facing the piezoelectric element, includes an external electrode tab region that overlaps in plan view with a region that integrally surrounds at least a part of the lower surface electrode terminal and at least a part of the lower surface electrode terminal facing region, the external electrode tab region having an external electrode connection opening; and an internal electrode tab region that overlaps in plan view with at least a part of the internal electrode terminal, the internal electrode tab region having an internal electrode connection opening.

[0023] A portion of the first wiring straddles the external electrode connection opening, and a portion of the second wiring straddles the internal electrode connection opening, the wiring body is fixed to the upper surface of the lower sealing plate in a state in which the external electrode connection opening overlaps in a planar view with a region integrally including at least a portion of the lower electrode terminal and at least a portion of the lower electrode opposing region, and the internal electrode connection opening overlaps in a planar view with at least a portion of the internal electrode terminal, the portion of the first wiring that straddles the external electrode connection opening is bonded to the first conductive bonding material, and the portion of the second wiring that straddles the internal electrode connection opening is bonded to the second conductive bonding material.

[0024] Preferably, the piezoelectric element overlapping portion of the insulating layer located on the side of the base layer and the cover layer away from the piezoelectric element may have an external electrode tab region that overlaps in a planar view with a region that integrally surrounds at least a portion of the lower electrode terminal and at least a portion of the lower electrode terminal opposing region, the external electrode tab region having a first access opening, and an internal electrode tab region that overlaps in a planar view with at least a portion of the internal electrode terminal, the second tab region having a second access opening.

[0025] In order to achieve the third object, a third aspect of the present invention provides a rigid substrate having a plurality of openings penetrating between an upper surface and a lower surface thereof, a flexible resin film fixed to the upper surface of the substrate so as to cover the plurality of openings, piezoelectric elements of the same number as the plurality of openings, each of which has a central region overlapping with a corresponding opening and a peripheral region overlapping with the upper surface of the substrate in a plan view, and a wiring body having first and second wirings electrically connected to an external electrode and an internal electrode of the piezoelectric element, respectively, wherein the piezoelectric element is formed of a piezoelectric material. a piezoelectric element body formed on the upper end surface of the piezoelectric element body, upper and lower electrodes respectively provided on the upper end surface and lower surface of the lower end surface of the piezoelectric element body and forming the external electrode; the internal electrode dividing the piezoelectric element body into upper and lower parts in the thickness direction; a lower electrode connector formed on the upper end surface of the piezoelectric element body with a base end side electrically connected to the lower electrode and a tip end side with a lower electrode side gap between it and the upper electrode, forming a lower electrode terminal; and a piezoelectric element body formed on the upper end surface of the piezoelectric element body with a base end side electrically connected to the internal electrode and a tip end side with an internal electrode side gap between it and the upper electrode, a flexible resin film fixing step of fixing the flexible resin film to the upper surface of the rigid substrate so as to cover the plurality of openings; a piezoelectric element fixing step of fixing the plurality of piezoelectric elements to the upper surface of the flexible resin film with an insulating adhesive so as to overlap the plurality of openings in a plan view; an insulating cover installation step of providing an insulating cover on the upper surface of the piezoelectric elements so as to integrally cover at least a portion of the internal electrode terminal, an internal electrode terminal facing region of the upper surface electrode that faces the internal electrode terminal across the internal electrode-side gap, and a region of the internal electrode-side gap that is sandwiched between the internal electrode terminal and the internal electrode terminal facing region; and an electrode exposure step of forming an internal electrode opening in the insulating cover, which exposes at least a portion of the internal electrode terminal but does not expose the internal electrode terminal facing region.The present invention provides a method for manufacturing an ultrasonic transducer, comprising: a conductive bonding material providing step of providing a first conductive bonding material so as to integrally cover at least a portion of the lower electrode terminal and at least a portion of a lower electrode terminal facing region of the upper electrode that faces the lower electrode terminal through the lower electrode-side gap, and providing a second conductive bonding material on a portion of the internal electrode terminal that is exposed through the internal electrode opening; and a wiring body providing step of installing the wiring body so that a portion of the first wiring contacts the first conductive bonding material and a portion of the second wiring contacts the second conductive bonding material.

[0026] In the third aspect, the electrode exposing step is preferably configured to form the internal electrode opening by irradiating a laser beam onto a region of the insulating cover body where the internal electrode opening is to be formed.

[0027] In a first form of the third aspect, the insulating cover body is configured so as not to cover at least a portion of the lower electrode terminal, a lower electrode terminal facing region of the upper electrode that faces the lower electrode terminal through the lower electrode side gap, and a region of the lower electrode side gap that is sandwiched between the lower electrode terminal and the lower electrode terminal facing region.

[0028] In a second embodiment of the third aspect, the insulating cover is configured to integrally cover at least a portion of the lower electrode terminal, a lower electrode terminal-facing region of the upper electrode that faces the lower electrode terminal across the lower electrode-side gap, and a region of the lower electrode-side gap that is sandwiched between the lower electrode terminal and the lower electrode terminal-facing region. In this case, the electrode exposing step is configured to form, in addition to the internal electrode opening, an external electrode opening that integrally exposes at least a portion of the lower electrode terminal and at least a portion of the upper electrode, and the conductive bonding material providing step is configured to provide the first conductive bonding material in the external electrode opening.

[0029] The manufacturing method according to the third aspect may further include a lower sealing plate fixing step of preparing a lower sealing plate having approximately the same thickness as the piezoelectric element and a central opening of a size sufficient to integrally surround the plurality of openings in the rigid substrate, and fixing the lower sealing plate to the upper surface of the flexible resin film so that the central opening integrally surrounds the plurality of openings in a planar view.

[0030] The lower sealing plate fixing process is performed at any timing after the flexible resin film fixing process and before the wiring body installation process, and the wiring body installation process is configured to place the wiring body on the lower sealing plate.

[0031] Preferably, the manufacturing method according to the third aspect may further include an insulating resin filling step, which is performed after the lower sealing plate fixing step and the piezoelectric element fixing step and before the wiring body installation step, of filling an insulating resin material into the lateral portions of each of the plurality of piezoelectric elements in the space surrounded by the central opening of the lower sealing plate.

[0032] In the manufacturing method according to the third aspect, the lower sealing plate preferably has partition walls that divide the central opening into a plurality of openings each large enough to surround one of the plurality of piezoelectric elements.

[0033] In order to achieve the third object, a fourth aspect of the present invention is a piezoelectric element comprising: a rigid substrate provided with a plurality of openings penetrating between an upper surface and a lower surface; a flexible resin film fixed to the upper surface of the substrate so as to cover the plurality of openings; piezoelectric elements, the number of which is equal to the number of the plurality of openings, fixed to the flexible resin film so that central regions overlap with corresponding openings and peripheral regions overlap with the upper surface of the substrate in a plan view; and a wiring body having first and second wirings electrically connected to external and internal electrodes of the piezoelectric elements, respectively, wherein the piezoelectric elements are piezoelectric elements formed of a piezoelectric material. a piezoelectric element body; an upper surface electrode and a lower surface electrode provided on the upper end surface and the lower end surface of the piezoelectric element body, respectively, and forming the external electrode; the internal electrode that divides the piezoelectric element body into upper and lower portions in the thickness direction; a lower surface electrode connector that is provided on the upper end surface of the piezoelectric element body with a base end side electrically connected to the lower surface electrode and a tip end side with a lower surface electrode side gap between it and the upper surface electrode, and forms a lower surface electrode terminal; and an internal electrode connector that is provided on the upper end surface of the piezoelectric element body with a base end side electrically connected to the internal electrode and a tip end side with an internal electrode side gap between it and the upper surface electrode. a rigid substrate forming step of forming the rigid substrate by preparing a rigid plate having the same thickness as the rigid substrate and forming the plurality of openings in the rigid plate; a flexible resin film fixing step of fixing the flexible resin film to the upper surface of the rigid substrate so as to cover the plurality of openings; and a lower sealing plate having a central opening of a size that surrounds all of the plurality of openings in a plan view, and fixing the lower sealing plate to the upper surface of the flexible resin film so that the central opening surrounds all of the plurality of openings. a piezoelectric element fixing step of fixing the plurality of piezoelectric elements to the upper surface of the flexible resin film with a first insulating resin material so as to overlap the plurality of openings in a plan view; an insulating resin material setting step of providing a second insulating resin material in the central opening so as to cover outer side surfaces of the plurality of piezoelectric elements and to cover upper end surfaces of the plurality of piezoelectric elements to form an insulating cover body; and an external electrode opening in the insulating cover body which integrally exposes at least a part of the lower surface electrode terminal and at least a part of the upper surface electrode.The present invention provides a method for manufacturing an ultrasonic transducer, comprising: an electrode exposing step of forming an internal electrode opening that exposes at least a portion of the internal electrode terminal while not exposing the internal electrode terminal facing region; a conductive bonding material providing step of providing a first conductive bonding material so as to integrally cover the portions of the lower surface electrode terminal and the upper surface electrode that are exposed through the external electrode opening, and providing a second conductive bonding material on the portion of the internal electrode terminal that is exposed through the internal electrode opening; and a wiring body providing step of providing the wiring body so that a portion of the first wiring contacts the first conductive bonding material and a portion of the second wiring contacts the second conductive bonding material.

[0034] In order to achieve the third object, a fifth aspect of the present invention provides a piezoelectric element comprising: a rigid substrate provided with a plurality of openings penetrating between an upper surface and a lower surface; a flexible resin film fixed to the upper surface of the substrate so as to cover the plurality of openings; piezoelectric elements, the number of which is equal to the plurality of openings, fixed to the flexible resin film so that central regions overlap with corresponding openings and peripheral regions overlap with the upper surface of the substrate in a plan view; and a wiring body having first and second wirings electrically connected to external and internal electrodes of the piezoelectric elements, respectively, wherein the piezoelectric elements are piezoelectric elements formed of a piezoelectric material. a piezoelectric element body; an upper surface electrode and a lower surface electrode provided on the upper end surface and the lower end surface of the piezoelectric element body, respectively, and forming the external electrode; the internal electrode that divides the piezoelectric element body into upper and lower portions in the thickness direction; a lower surface electrode connector that is provided on the upper end surface of the piezoelectric element body with a base end side electrically connected to the lower surface electrode and a tip end side with a lower surface electrode side gap between it and the upper surface electrode, and forms a lower surface electrode terminal; and an internal electrode connector that is provided on the upper end surface of the piezoelectric element body with a base end side electrically connected to the internal electrode and a tip end side with an internal electrode side gap between it and the upper surface electrode. a rigid substrate forming step of forming the rigid substrate by preparing a rigid plate material having the same thickness as the rigid substrate and forming the plurality of openings in the rigid plate material; a flexible resin film fixing step of fixing the flexible resin film to the upper surface of the rigid substrate so as to cover the plurality of openings; a piezoelectric element fixing step of fixing the plurality of piezoelectric elements to the upper surface of the flexible resin film with a first insulating resin material so as to overlap with the plurality of openings in a plan view; a lower sealing plate installation step of preparing a lower sealing plate having a central opening large enough to surround all of the plurality of openings, and fixing the lower sealing plate to the upper surface of the flexible resin film so that the central opening surrounds all of the plurality of openings; an insulating resin material installation step of providing a second insulating resin material within the central opening so as to cover outer side surfaces of the plurality of piezoelectric elements and to cover upper end surfaces of the plurality of piezoelectric elements to form an insulating cover body; and an external electrode opening in the insulating cover body which integrally exposes at least a portion of the lower surface electrode terminal and at least a portion of the upper surface electrode.The present invention provides a method for manufacturing an ultrasonic transducer, comprising: an electrode exposing step of forming an internal electrode opening that exposes at least a portion of the internal electrode terminal while not exposing the internal electrode terminal facing region; a conductive bonding material providing step of providing a first conductive bonding material so as to integrally cover the portions of the lower surface electrode terminal and the upper surface electrode that are exposed through the external electrode opening, and providing a second conductive bonding material on the portion of the internal electrode terminal that is exposed through the internal electrode opening; and a wiring body providing step of providing the wiring body so that a portion of the first wiring contacts the first conductive bonding material and a portion of the second wiring contacts the second conductive bonding material.

[0035] In order to achieve the third object, a sixth aspect of the present invention provides a method for manufacturing a piezoelectric element, comprising: a rigid substrate having a plurality of openings penetrating between an upper surface and a lower surface; a flexible resin film fixed to the upper surface of the substrate so as to cover the plurality of openings; piezoelectric elements, the number of which is equal to the number of the plurality of openings, fixed to the flexible resin film so that central regions overlap with the corresponding openings and peripheral regions overlap with the upper surface of the substrate in a plan view; and a wiring body having first and second wirings electrically connected to external and internal electrodes of the piezoelectric elements, respectively, wherein the piezoelectric elements are piezoelectric element bodies formed of a piezoelectric material. an upper surface electrode and a lower surface electrode provided on the upper end surface and the lower end surface of the piezoelectric element body, respectively, and forming the external electrode; an internal electrode that divides the piezoelectric element body into upper and lower portions in the thickness direction; a lower surface electrode connector that is provided on the upper end surface of the piezoelectric element body with a base end side electrically connected to the lower surface electrode and a tip end side with a lower surface electrode side gap between it and the upper surface electrode, and forms a lower surface electrode terminal; and a lower surface electrode connector that is provided on the upper end surface of the piezoelectric element body with a base end side electrically connected to the internal electrode and a tip end side with an internal electrode side gap between it and the upper surface electrode, and forms an internal electrode terminal. a rigid substrate forming step of forming the rigid substrate by preparing a rigid plate material having the same thickness as the rigid substrate and forming the plurality of openings in the rigid plate material; a flexible resin film fixing step of fixing the flexible resin film to an upper surface of the rigid substrate so as to cover the plurality of openings; and a lower sealing plate having a thickness greater than that of the piezoelectric element and having a central opening of a size that surrounds all of the plurality of openings in a plan view. a lower sealing plate installation step of fixing the lower sealing plate to the upper surface of the flexible resin film; an insulating resin filling step of filling the central opening with insulating resin material; a piezoelectric element fixing step of installing the plurality of piezoelectric elements in the insulating resin material on the upper surface of the flexible resin film so that a portion of the insulating resin material covers the upper end surfaces of the piezoelectric elements and overlaps with the plurality of openings in a plan view, and fixing the plurality of piezoelectric elements to the flexible resin film with the insulating resin material;The present invention provides a method for manufacturing an ultrasonic transducer, comprising: an electrode exposing step of forming an external electrode opening that integrally exposes at least a portion of the lower surface electrode terminal and at least a portion of the upper surface electrode, and an internal electrode opening that exposes at least a portion of the internal electrode terminal but not an area facing the internal electrode terminal; a conductive bonding material providing step of providing a first conductive bonding material so as to integrally cover the portions of the lower surface electrode terminal and the upper surface electrode that are exposed through the external electrode opening, and providing a second conductive bonding material on the portion of the internal electrode terminal that is exposed through the internal electrode opening; and a wiring body providing step of providing the wiring body so that a portion of the first wiring contacts the first conductive bonding material and a portion of the second wiring contacts the second conductive bonding material.

[0036] In the manufacturing methods according to the fourth to sixth aspects, the electrode exposure process is preferably configured to form the external electrode opening and the internal electrode opening by irradiating laser light onto an area of ​​the insulating cover body where the external electrode opening is to be formed and an area where the internal electrode opening is to be formed.

[0037] In the manufacturing methods according to the fourth to sixth aspects, the lower sealing plate preferably has partitions that divide the central opening into a plurality of openings each large enough to surround one of the plurality of piezoelectric elements.

[0038] FIG. 1 is a plan view of an ultrasonic transducer including a piezoelectric element according to a first embodiment of the present invention. FIG. 2 is a partial longitudinal cross-sectional view of the ultrasonic transducer taken along line II-II in FIG. 1. FIG. 3 is an enlarged view of section III in FIG. 2. FIG. 4 is a cross-sectional view taken along section IV-IV in FIG. 2. FIG. 5 is an enlarged view of section V in FIG. 4. FIGS. 6(a) to 6(d) are plan views of the components of the ultrasonic transducer, including a rigid substrate, a flexible resin film, multiple piezoelectric elements, and a lower sealing plate. In the state shown in FIG. 2, the components in FIGS. 6(a) to 6(d) are stacked in order from bottom to top. FIGS. 7(a) to 7(e) are plan views of the wiring body, which are components of the ultrasonic transducer, including a cover layer, first and second wirings, a base layer, an intermediate region in the first wiring, and a back cover layer. In the state shown in FIG. 2, the components in FIGS. 7(a) to 7(e) are stacked in order from bottom to top. FIG. 8(a) is a plan view of a piezoelectric element according to the first embodiment, and FIG. 8(b) is a cross-sectional view taken along line VIII-VIII in FIG. 8(a). FIG. 9(a) is a plan view of a piezoelectric element according to a first modified example of the first embodiment, and FIG. 9(b) is a cross-sectional view taken along line IX-IX in FIG. 8(a). FIG. 10(a) is a plan view of a piezoelectric element according to a second modified example of the first embodiment, and FIG. 10(b) is a cross-sectional view taken along line XX in FIG. 10(a). FIG. 11(a) is a plan view of a piezoelectric element according to a third modified example of the first embodiment, and FIG. 11(b) is a cross-sectional view taken along line XI-XI in FIG. 11(a). FIG. 12(a) is a plan view of a piezoelectric element according to a fourth modified example of the first embodiment, and FIG. 12(b) is a cross-sectional view taken along line XII-XII in FIG. 12(a). Fig. 13(a) is a plan view of a piezoelectric element according to a fifth modified example of the first embodiment, and Fig. 13(b) is a cross-sectional view taken along line XIII-XIII in Fig. 13(a). Fig. 14(a) is a plan view of a piezoelectric element according to a sixth modified example of the first embodiment, and Fig. 14(b) is a cross-sectional view taken along line XIV-XIV in Fig. 14(a). Fig. 15(a) is a plan view of a piezoelectric element according to a seventh modified example of the first embodiment, and Fig. 15(b) is a cross-sectional view taken along line XV-XV in Fig. 15(a).FIG. 16 is a plan view of the wiring body, with some components omitted. FIG. 17 is a bottom view of the wiring body, with some components omitted. FIGS. 18(a) to 18(c) are plan views of the components of the ultrasonic transducer, namely, the upper sealing plate, the sound-absorbing material, and the reinforcing plate. In the state shown in FIG. 2, the components of FIGS. 18(a) to 18(c) are stacked in order from bottom to top. FIG. 19 is a vertical cross-sectional view showing a state after the flexible resin film fixing step in the manufacturing method of the ultrasonic transducer including the piezoelectric element according to the first embodiment (hereinafter referred to as the first manufacturing method). FIG. 20 is a vertical cross-sectional view showing a state after the lower sealing plate fixing step in the first manufacturing method. FIG. 21 is a vertical cross-sectional view showing a state after the insulating resin material filling step in the first manufacturing method. FIG. 22 is a vertical cross-sectional view showing a state after the insulating cover installation step in the first manufacturing method. FIG. 23 is an enlarged view of portion XXIII in FIG. 22. FIG. 24 is a plan view of the piezoelectric element after the insulating cover installation step. FIG. 25 is a longitudinal sectional view showing a state after the electrode exposing step in the first manufacturing method. FIG. 26 is an enlarged view of portion XXVI in FIG. 25. FIG. 27 is a plan view of the piezoelectric element after the electrode exposing step. FIG. 28 is a longitudinal sectional view showing a state after the conductive bonding material installation step in the first manufacturing method. FIG. 29 is an enlarged view of portion XXIX in FIG. 28. FIG. 30 is a longitudinal sectional view showing a state after the wiring body installation step in the first manufacturing method. FIG. 31 is an enlarged view of portion XXXI in FIG. 30. FIG. 32 is a longitudinal sectional view showing a state after the upper sealing plate installation step in the first manufacturing method. FIG. 33 is a partial longitudinal sectional view of an ultrasonic transducer according to embodiment 2 of the present invention. FIG. 34 is an enlarged view of portion XXXIV in FIG. 33. FIG. 35 is a partial enlarged longitudinal sectional view of an ultrasonic transducer according to a modified example of embodiment 2. Fig. 36 is a longitudinal cross-sectional view showing a state after a flexible resin film fixing step in a manufacturing method for an ultrasonic transducer according to the second embodiment (hereinafter referred to as a second manufacturing method). Fig. 37 is a longitudinal cross-sectional view showing a state after a lower sealing plate fixing step in the second manufacturing method. Fig. 38 is a longitudinal cross-sectional view showing a state after a piezoelectric element fixing step in the second manufacturing method.FIG. 39 is a vertical cross-sectional view showing a state after the insulating resin material applying step in the second manufacturing method. FIG. 40 is an enlarged view of the XXXX portion in FIG. 39. FIG. 41 is a plan view of the piezoelectric element after the insulating resin material applying step. FIG. 42 is a partially enlarged vertical cross-sectional view showing a state after the electrode exposing step in the second manufacturing method. FIG. 43 is a plan view of the piezoelectric element after the electrode exposing step. FIG. 44 is a vertical cross-sectional view showing a state after the conductive bonding material applying step in the second manufacturing method. FIG. 45 is an enlarged view of the XXXXV portion in FIG. 44. FIG. 46 is a vertical cross-sectional view showing a state after the wiring body applying step in the second manufacturing method. FIG. 47 is an enlarged view of the XXXXVII portion in FIG. 46. FIG. 48 is a vertical cross-sectional view showing a state after the upper sealing plate applying step in the second manufacturing method. FIG. 49 is a vertical cross-sectional view showing a state after the insulating resin material filling step in the second manufacturing method. FIG. 50 is a vertical cross-sectional view showing a state after the piezoelectric element fixing step in the second manufacturing method. Fig. 51 is an enlarged view of part XXXXXI in Fig. 50. Fig. 52 is a plan view of a piezoelectric element according to another embodiment of the present invention. Fig. 53 is a plan view of a lower sealing plate used in an ultrasonic transducer according to a modified example of the present invention. Fig. 54 is a partial vertical cross-sectional view of the ultrasonic transducer according to the modified example of the present invention, which is provided with the lower sealing plate shown in Fig. 53.

[0039] Embodiment 1 Hereinafter, one embodiment of a piezoelectric element according to the present invention will be described with reference to the accompanying drawings. Fig. 1 shows a plan view of an ultrasonic transducer 1 including a piezoelectric element 30 according to this embodiment. Note that in Fig. 1, some of the components of the ultrasonic transducer 1 are omitted for ease of understanding. Fig. 2 shows a partial longitudinal sectional front view taken along line II-II in Fig. 1. Furthermore, Fig. 3 shows an enlarged view of part III in Fig. 2. Furthermore, Fig. 4 shows a cross-sectional view taken along part IV-IV in Fig. 2, and Fig. 5 shows an enlarged view of part V in Fig. 4.

[0040] First, a description will be given of the ultrasonic transducer 1. The ultrasonic transducer 1 receives a voltage supply to emit ultrasonic waves, and generates a voltage in response to receiving ultrasonic waves.

[0041] The ultrasonic transducer 1 includes, from bottom to top with reference to the cross-sectional view of FIG. 2, a rigid substrate 10, a flexible resin film 20, a plurality of piezoelectric elements 30, a lower sealing plate 40, and a wiring body 100.

[0042] 6(a) to 6(d) show plan views of the rigid substrate 10, the flexible resin film 20, the plurality of piezoelectric elements 30, and the lower sealing plate 40, respectively. Also, FIGS. 7(a) to 7(e) show plan views of each component of the wiring body 100. Note that in FIGS. 6(a) to 6(d) and 7(a) to 7(e), center lines are drawn at the same position in a plan view to facilitate understanding of the relative positional relationship of each component.

[0043] The rigid substrate 10 is formed, for example, from a metal substrate such as stainless steel having a thickness of 0.1 mm to 0.4 mm, carbon fiber reinforced plastic, ceramics, etc. As shown in Figures 2 and 6(a), the rigid substrate 10 has a plurality of openings 15 penetrating between the upper surface 11 and the lower surface 12.

[0044] The opening 15 has a cavity 16 that opens to the upper surface 11 of the rigid substrate 10 , and a waveguide 17 that opens at one end to the bottom surface of the cavity 16 and at the other end to the lower surface 12 of the rigid substrate 10 .

[0045] The cavity 16 has the same shape in plan view as the piezoelectric element 30. In this embodiment, the piezoelectric element 30 has a rectangular shape in plan view, and therefore the cavity 16 also has a rectangular shape in plan view.

[0046] The opening width of the cavity 16 is set so that when the piezoelectric element 30 is placed via the flexible resin film 20, the periphery of the piezoelectric element 30 overlaps with the upper surface 11 of the rigid substrate 10 in a planar view.

[0047] The waveguide 17 has an opening width smaller than that of the cavity 16. In this embodiment, the waveguide 17 has a circular shape in a plan view.

[0048] In this embodiment, as shown in Figure 6(a), nine openings 15 (3 x 3) are provided in the rigid substrate 10, and nine piezoelectric elements 30 are arranged so as to overlap with each of the nine openings 15 in a planar view with the flexible resin film 20 sandwiched between them.

[0049] That is, nine piezoelectric elements 30, each acting as a vibrator, are arranged in a 3 × 3 array in the ultrasonic transducer 1. For example, in order to sharpen the directionality of the radiated sound waves of the ultrasonic transducer 1 and increase the intensity of the radiated sound waves, it is possible to arrange more vibrators (piezoelectric elements 30) than 3 × 3.

[0050] The flexible resin film 20 is fixed to the upper surface 11 of the substrate 10 so as to cover the plurality of openings 15. The flexible resin film 20 is formed of an insulating resin such as polyimide with a thickness of 20 μm to 100 μm, for example. The flexible resin film 20 is fixed to the rigid substrate 10 by various methods such as an adhesive or thermocompression bonding.

[0051] FIG. 8(a) shows a plan view of the piezoelectric element 30, and FIG. 8(b) shows a cross-sectional view taken along line VIII-VIII in FIG. 8(a).

[0052] The piezoelectric element 30 is fixed to the upper surface of the flexible resin film 20 so that its central portion in a planar view overlaps with the corresponding opening 15 (the hollow portion 16) and its peripheral portion in a planar view overlaps with the portion of the rigid substrate 10 that surrounds the corresponding opening 15 (the hollow portion 16).

[0053] The piezoelectric element 30 is of a laminated type. In more detail, the piezoelectric element 30 includes a piezoelectric element body 32 formed of a piezoelectric material such as lead zirconate titanate (PZT), an internal electrode 34 that divides the piezoelectric element body 32 into a first piezoelectric portion 32a on the upper side and a second piezoelectric portion 32b on the lower side in the thickness direction, an upper electrode 36 fixed to a part of the upper end surface of the first piezoelectric portion 32a, a lower electrode 37 fixed to the lower end surface of the second piezoelectric portion 32b, an internal electrode connector 35 that is electrically connected to the internal electrode 34 at its base end and is provided on the upper end surface of the piezoelectric element body 32 with an internal electrode gap 34a existing between its tip end and the upper electrode 36, thereby forming an internal electrode terminal 34T, and a lower electrode connector 38 that is electrically connected to the lower electrode 37 at its base end and is provided on the upper end surface of the piezoelectric element body 32 with a lower electrode gap 37a existing between its tip end and the upper electrode 36, thereby forming a lower electrode terminal 37T.

[0054] The piezoelectric element 30 acts as a vibrating body of the ultrasonic transducer 1. For example, when the frequency of the driving voltage applied to the piezoelectric element 30 is 40 kHz, the piezoelectric element 30 may have a resonance frequency of about 70 kHz and a rectangular shape with sides of 3.0 mm in plan view. In this case, the layer thickness of the first and second piezoelectric portions 32a, 32b may be 0.1 mm to 0.2 mm.

[0055] The upper electrode 36, the lower electrode 37 and the internal electrode 34 can be formed of a metal film such as Au, AgPd or Pt having a thickness of about 1 μm to 10 μm.

[0056] In the piezoelectric element 30, the upper surface electrode 36 and the lower surface electrode 37 form external electrodes, and are configured to expand and contract when a voltage is applied between the external electrode and the internal electrode 34.

[0057] That is, the polarization direction of the first and second piezoelectric portions 32a, 32b is the same in the thickness direction, so that by applying a predetermined voltage at a predetermined frequency between the external electrodes (the upper electrode 36 and the lower electrode 37) and the internal electrode 34, electric fields in opposite directions relative to each other are applied to the first and second piezoelectric portions 32a, 32b.

[0058] The upper electrode 36 and the lower electrode 37 are insulated from each other. Therefore, when the piezoelectric element 30 is fabricated, the polarization directions of the first and second piezoelectric portions 32 a, 32 b can be made the same by applying a voltage between the upper electrode 36 and the lower electrode 37.

[0059] In the piezoelectric element 30 having such a configuration, the electrical connection of the wiring (in this embodiment, the first wiring 130a in the wiring body 100 described below) to be connected to the external electrodes (the upper electrode 36 and the lower electrode 37) to the upper electrode 36 and the lower electrode 37, and the electrical connection of the wiring (in this embodiment, the second wiring 130b in the wiring body 100 described below) to be connected to the internal electrode 34 to the internal electrode 34 can all be made on the upper end surface on one side in the thickness direction of the piezoelectric element 30.

[0060] That is, in the piezoelectric element 30, as described above, the lower electrode terminal 37T is provided on the upper end surface of the piezoelectric element body 32 while being spaced apart from the upper electrode 36 via the lower electrode side gap 37a, and the internal electrode terminal 34T is provided on the upper end surface of the piezoelectric element body 32 while being spaced apart from the upper electrode 36 via the internal electrode side gap 34a.

[0061] Therefore, as shown in FIG. 4 , a first conductive bonding material 190a is provided so as to integrally cover at least a portion of the lower electrode terminal 37T and at least a portion of a lower electrode terminal opposing region 361 of the upper electrode 36 that faces the lower electrode terminal 37T via the lower electrode-side gap 37a, and the wiring to be connected to the external electrode (the first wiring 130a in this embodiment) is fixed to the first conductive bonding material 190a, while a second conductive bonding material 190b is provided so as to cover at least a portion of the internal electrode terminal 34T, and the wiring to be connected to the internal electrode 34 (the second wiring 130b in this embodiment) is fixed to the second conductive bonding material 190b. As a result, electrical connection between the wiring to be connected to the external electrode (the first wiring 130a in this embodiment) and the external electrode, and electrical connection between the wiring to be connected to the internal electrode 34 (the second wiring 130b in this embodiment) and the internal electrode 34 can be made on the upper end surface on one side in the thickness direction of the piezoelectric element 30.

[0062] The first and second conductive bonding materials 190a and 190b may be, for example, a conductive adhesive or cream solder.

[0063] As shown in Figures 4 and 7, an insulating cover body 300A is provided on the upper end surface of the piezoelectric element 30 in this embodiment so as to integrally cover at least a portion of the internal electrode terminal 34T, an internal electrode terminal facing region 362 of the upper surface electrode 36 that faces the internal electrode terminal 34T via the internal electrode side gap 34a, and a region of the internal electrode side gap 34a that is sandwiched between the internal electrode terminal 34T and the internal electrode terminal facing region 362.

[0064] The insulating cover body 300A is formed, for example, by a coating of an insulating resin such as polyimide resin, silicone resin, epoxy resin, or ceramics, with a thickness of several μm to several tens of μm.

[0065] When the insulating cover body 300A is formed by a coating of epoxy resin or silicone resin, the resin can be applied to a predetermined position using a dispenser or screen printing, and then heated at a predetermined temperature (e.g., 120°C to 150°C) to harden, thereby efficiently forming the insulating cover body 300A.

[0066] 8( a), in this embodiment, the insulating cover body 300A is configured to cover the entire internal electrode terminal 34T. The insulating cover body 300A is provided with an internal electrode opening 315A (through hole or notch) that exposes at least a part of the internal electrode terminal 34T but does not expose the internal electrode terminal facing region 362.

[0067] With this configuration, it is possible to improve the conversion efficiency between voltage and flexural vibration in the piezoelectric element 30 as much as possible, while effectively preventing short circuits between the external electrode (the upper surface electrode 36) and the internal electrode 34.

[0068] That is, in order to improve the conversion efficiency between the voltage and flexural vibration of the piezoelectric element 30, it is necessary to increase as much as possible the opposing areas of the external electrode and the internal electrode 34, i.e., the opposing areas of the upper electrode 36 and the internal electrode 34, and the opposing areas of the internal electrode 34 and the lower electrode 37; and by increasing the area of ​​the upper electrode 36 as much as possible, it is possible to increase the opposing areas of the upper electrode 36 and the internal electrode 34.

[0069] However, the increase in the area of ​​the upper surface electrode 36 leads to a narrowing of the internal electrode side gap 34a, and when a second conductive bonding material 190b that electrically connects the internal electrode terminal 34T to the wiring to be connected (the second wiring 130b in this embodiment) is provided on the internal electrode terminal 34T, variations in the amount of application or the application position of the second conductive bonding material 190b increase the risk that the second conductive bonding material 190b will come into contact with the upper surface electrode 36. This leads to a decrease in yield due to a short circuit between the external electrode (the upper electrode 36) and the internal electrode 34, or a decrease in the efficiency of the installation work of the second conductive bonding material 190b.

[0070] In this regard, in the present embodiment, as described above, at least a portion of the internal electrode terminal 34T, the internal electrode terminal facing region 362 of the upper surface electrode 36 that faces the internal electrode terminal 34T via the internal electrode side gap 34a, and the region of the internal electrode side gap 34a that is sandwiched between the internal electrode terminal 34T and the internal electrode terminal facing region 362 are integrally covered by the insulating cover body 300A, and at least a portion of the internal electrode terminal 34T is exposed via the internal electrode opening 315A formed in the insulating cover body 300A.

[0071] Therefore, in order to improve the conversion efficiency of the piezoelectric element 30, the area of ​​the upper electrode 36 is enlarged. As a result, even if the internal electrode side gap 34a is narrowed, the second conductive adhesive material 190b applied to the portion of the internal electrode terminal 34T exposed through the internal electrode opening 315A comes into contact with the upper electrode 36, effectively preventing a short circuit between the upper electrode 36 (i.e., the external electrode) and the internal electrode 34.

[0072] Furthermore, narrowing the internal electrode side gap 34a may cause ion migration and lead to short circuit defects under the environmental conditions in which the piezoelectric element 30 is used, such as high temperature and humidity, even if the second conductive bonding material 190b does not come into contact with the upper surface electrode 36 during installation of the second conductive bonding material 190b. However, in this embodiment, such a situation can be effectively prevented.

[0073] Furthermore, the edge of the internal electrode opening 315A can effectively prevent the second conductive bonding material 190b applied to the portion of the internal electrode terminal 34T exposed through the internal electrode opening 315A from flowing out, and the application work of the second conductive bonding material 190b can be performed using the internal electrode opening 315A as a landmark.

[0074] The internal electrode opening 315A is suitably formed by irradiating a desired portion of the insulating cover body 300A with laser light from a laser device and peeling off the predetermined portion.

[0075] The internal electrode opening 315A has an opening diameter of, for example, about 0.5 to 1 mm, and furthermore, the internal electrode terminal 34T has a thickness of, for example, about 0.1 to 0.2 mm, so it is preferable to use laser light that has a small spot diameter and a high absorption rate into the target organic material (in this case, the insulating cover body 300A).

[0076] Specifically, among the solid-state laser wavelengths effective for processing resin materials, the third harmonic (355 nm), which is a laser wavelength shorter than the fundamental wavelength (1064 nm), can be used. With such laser light, the spot diameter can be reduced to nearly the wavelength when focused on a lens, allowing for fine peeling.

[0077] Furthermore, the shorter the wavelength of laser light, the higher the light energy, and for materials with weak molecular bonds, photodecomposition processing can be performed, which directly cuts the molecular bonds, enabling efficient processing with little thermal impact.

[0078] As laser light that is highly absorbed by resin materials, UV laser light of the third harmonic (355 nm) of a solid-state laser or DUV laser light of the fourth harmonic (266 nm) is preferably used.

[0079] The internal electrode openings 315A can also be formed by an ion beam, an electron beam, or ion milling.

[0080] 9A and 9B are a plan view and a cross-sectional view taken along line IX-IX in FIG. 9A, respectively, of a piezoelectric element 30 according to a first modified example of the present embodiment.

[0081] As shown in Figures 8(a) and (b), in this embodiment, the internal electrode opening 315A is configured to expose not only at least a part of the internal electrode terminal 34T, but also a region of the internal electrode side gap 34a that is adjacent to the exposed region of the internal electrode terminal 34T.

[0082] In contrast to this, the internal electrode opening 315B in the first modified example is configured so as to expose only at least a part of the internal electrode terminal 34T and not to expose the internal electrode gap 34a.

[0083] 10(a) and 10(b) respectively show a plan view of a piezoelectric element 30 according to a second modified example of the present embodiment and a cross-sectional view taken along line XX in Fig. 10(a). Furthermore, Fig. 11(a) and 11(b) respectively show a plan view of a piezoelectric element 30 according to a third modified example of the present embodiment and a cross-sectional view taken along line XI-XI in Fig. 11(a).

[0084] In this embodiment and the first modified example, the insulating cover body 300A is configured to cover the entire inner electrode terminal 34T.

[0085] In contrast to this, the piezoelectric elements according to the second and third modifications are provided with an insulating cover body 300B instead of the insulating cover body 300A.

[0086] The insulating cover body 300B is configured to integrally cover a portion of the internal electrode terminal 34T, an internal electrode terminal facing region 362 of the upper surface electrode 36 that faces the internal electrode terminal 34T through the internal electrode side gap 34a, and a region of the internal electrode side gap 34a that is sandwiched between the internal electrode terminal 34T and the internal electrode terminal facing region 362.

[0087] In addition, the internal electrode opening 315A in the second modified example is configured to expose at least a portion of the internal electrode terminal 34T as well as a region of the internal electrode side gap 34a adjacent to the exposed region of the internal electrode terminal 34T, and the internal electrode opening 315B in the third modified example is configured to expose only at least a portion of the internal electrode terminal 34T and not to expose the internal electrode side gap 34a.

[0088] Furthermore, FIGS. 12(a) and 12(b) show a plan view and a cross-sectional view taken along line XII-XII in FIG. 12(a), respectively, of a piezoelectric element 30 according to a fourth modified example of this embodiment. FIGS. 13(a) and 13(b) show a plan view and a cross-sectional view taken along line XIII-XIII in FIG. 13(a), respectively, of a piezoelectric element 30 according to a fifth modified example of this embodiment. FIGS. 14(a) and 14(b) show a plan view and a cross-sectional view taken along line XIV-XIV in FIG. 14(a), respectively, of a piezoelectric element 30 according to a sixth modified example of this embodiment. FIGS. 15(a) and 15(b) show a plan view and a cross-sectional view taken along line XV-XV in FIG. 15(a), respectively, of a piezoelectric element 30 according to a seventh modified example of this embodiment.

[0089] The insulating cover body 300A in the present embodiment and the first modified example, and the insulating cover body 300B in the second and third modified examples, are configured to integrally cover at least a portion of the internal electrode terminal 34T, an internal electrode terminal facing region 362 of the upper surface electrode 36 that faces the internal electrode terminal 34T via the internal electrode side gap 34a, and a region of the internal electrode side gap 34a that is sandwiched between the internal electrode terminal 34T and the internal electrode terminal facing region 362, while not covering the lower surface electrode terminal 37T, a lower surface electrode terminal facing region 361 of the upper surface electrode 36 that faces the lower surface electrode terminal 37T via the lower surface electrode side gap 37a, and a region of the lower surface electrode side gap 37a that is sandwiched between the lower surface electrode terminal 37T and the lower surface electrode terminal facing region 361.

[0090] In contrast, the insulating cover body 300C of the piezoelectric element 30 according to the fourth and fifth modified examples and the insulating cover body 300D of the piezoelectric element 30 according to the sixth and seventh modified examples are configured to integrally cover at least a portion of the internal electrode terminal 34T, an internal electrode terminal facing region 362 of the upper surface electrode 36 that faces the internal electrode terminal 34T via the internal electrode side gap 34a, and the region of the internal electrode side gap 34a that is sandwiched between the internal electrode terminal 34T and the internal electrode terminal facing region 362, as well as at least a portion of the lower surface electrode terminal 37T, a lower surface electrode terminal facing region 361 of the upper surface electrode 36 that faces the lower surface electrode terminal 37T via the lower surface electrode side gap 36a, and the region of the lower surface electrode side gap 37a that is sandwiched between the lower surface electrode terminal 37T and the lower surface electrode terminal facing region 361.

[0091] Specifically, the insulating cover body 300C of the piezoelectric element 30 according to the fourth and fifth modifications is configured to cover substantially the entire upper end surface of the piezoelectric element 30. On the other hand, the insulating cover body 300D of the piezoelectric element 30 according to the sixth and seventh modifications is sized to cover a portion of the upper end surface of the piezoelectric element 30.

[0092] Furthermore, in the fourth and sixth modified examples, the insulating cover bodies 300C and 300D are provided with an opening 315A for the internal electrode and an opening 310A (through hole or cutout) for the external electrode that integrally exposes at least a portion of the lower electrode terminal 37T and at least a portion of the upper electrode 36.

[0093] In the fifth modified example, the insulating cover 300C is provided with the internal electrode opening 315B and the external electrode opening 310A. In the seventh modified example, the insulating cover 300C is provided with the internal electrode opening 315A and an external electrode opening 310B (through hole or cutout) that integrally exposes the entire lower surface electrode terminal 37T and at least a part of the upper surface electrode 36.

[0094] The wiring body 100 is configured to transmit an applied voltage supplied from the outside to the plurality of piezoelectric elements 30 .

[0095] 16 and 17 respectively show a plan view (viewed from the side opposite to the piezoelectric element 30) and a bottom view (viewed from the side of the piezoelectric element 30) of the wiring body 100. For ease of understanding, a cover layer 150 described below is omitted from illustration in FIGS.

[0096] As shown in Figures 7, 16, and 17, the wiring body 100 has an insulating base layer 110, a conductor layer 120 including the first and second wirings 130a, 130b fixed to the base layer 110, and an insulating cover layer 150 covering at least a portion of the conductor layer 120 from the side opposite the base layer 110.

[0097] The base layer 110 and the cover layer 150 are formed of an insulating resin such as polyimide.

[0098] As shown in Figure 16, the base layer 110 has a plurality of base-side piezoelectric element overlapping portions 111 that partially overlap each of the plurality of piezoelectric elements 30 in a planar view, and a base-side tip portion 116 that holds the plurality of base-side piezoelectric element overlapping portions 111 together.

[0099] As described above, the ultrasonic transducer 1 has nine piezoelectric elements 30, numbered 1 to 9. Therefore, the base layer 110 has nine base-side piezoelectric element overlapping portions 111 corresponding to the nine piezoelectric elements 30, respectively.

[0100] Similarly, as shown in Figure 7(a), the cover layer 150 has a plurality of cover-side piezoelectric element overlapping portions 151 that partially overlap each of the plurality of piezoelectric elements 30 in a planar view, and a cover-side tip portion 156 that holds the plurality of cover-side piezoelectric element overlapping portions 151 together.

[0101] The cover-side piezoelectric element overlapping portions 151 are also provided in a number corresponding to the number of the plurality of piezoelectric elements.

[0102] The piezoelectric element overlapping portion 151 of the insulating layer on the piezoelectric element side (in this embodiment, the cover layer 150 (see Figure 2)) located on the side of the base layer 110 and the cover layer 150 facing the piezoelectric element has an external electrode tab region 152a that overlaps in a planar view with a region that integrally surrounds at least a portion of the lower surface electrode terminal 37T and at least a portion of the lower surface electrode terminal opposing region 361, and an internal electrode tab region 152b that overlaps in a planar view with a region that surrounds at least a portion of the internal electrode terminal 34T.

[0103] As shown in FIGS. 2, 5 and 7, the external electrode tab region 152a and the internal electrode tab region 152b are provided with external electrode connection openings 155a and internal electrode connection openings 155b, respectively.

[0104] The first and second wirings 130a, 130b are formed of a conductive metal such as Cu. The first and second wirings 130a, 130b can be formed by etching away unnecessary portions of Cu foil having a thickness of approximately 12 to 25 μm that is laminated on the base layer 110. Preferably, Ni / Au plating can be applied to the exposed portions of Cu that form the first and second wirings 130a, 130b.

[0105] As shown in FIG. 5, a portion of the first wiring 130a straddles the external electrode connection opening 155a, and a portion of the second wiring 130b straddles the internal electrode connection opening 155b.

[0106] The wiring body 100 is fixed to the upper surface of the lower sealing plate 40 in a state in which the external electrode connection opening 155a overlaps in a planar view with a region integrally including at least a portion of the lower electrode terminal 37T and at least a portion of the lower electrode opposing region 361, and the internal electrode connection opening 155b overlaps in a planar view with at least a portion of the internal electrode terminal 34T, and the portion of the first wiring 130a that straddles the external electrode connection opening 155a is joined to the first conductive bonding material 190a, and the portion of the second wiring 130b that straddles the internal electrode connection opening 155b is joined to the second conductive bonding material 190b.

[0107] In this embodiment, the piezoelectric element overlapping portion 111 of the insulating layer (in this embodiment, the base layer 110 (see Figure 2)) located on the side of the base layer 110 and the cover layer 150 that is away from the piezoelectric element 30 also has, similar to the piezoelectric element side insulating layer (in this embodiment, the cover layer 150), an external electrode tab region 112a that overlaps in a planar view with a region that integrally surrounds at least a portion of the lower electrode terminal 37T and at least a portion of the lower electrode terminal opposing region 361, and an internal electrode tab region 112b that overlaps in a planar view with at least a portion of the internal electrode terminal 34T.

[0108] The outer electrode tab region 112a and the inner electrode tab region 112b are provided with first and second access openings 115a and 115b, respectively.

[0109] In this embodiment, the first wiring 130a is a common wiring that is electrically connected to the external electrodes of the plurality of piezoelectric elements 30 as a whole, and the second wiring 130b is an individual wiring that is electrically connected to each of the internal electrodes 34 of the plurality of piezoelectric elements 30 individually.

[0110] The first wiring 130a is arranged on the surface of the base layer 110 facing the piezoelectric elements at its tip side 136a, which is electrically connected to the external electrodes of the plurality of piezoelectric elements 30, and its base side 138a, which forms a connection terminal with the outside, and is arranged on the surface of the base layer 110 facing the piezoelectric elements 30 at its intermediate portion 137a, which connects the tip side 136a and the base side 138a.

[0111] The tip side 136a and the intermediate portion 137a of the first wiring 130a are electrically connected via a through hole 109 formed in the base layer 110, and the intermediate portion 137a and the base side 138a of the first wiring 130a are electrically connected via a through hole 108 formed in the base layer 110.

[0112] The portion of the first wiring 130a disposed on the surface of the base layer 110 opposite to the piezoelectric element 30 is covered with a back cover layer 160 (see FIG. 6(e)).

[0113] The second wiring 130b is disposed over the entire area on the surface of the base layer 110 facing the piezoelectric element.

[0114] As described above, in the ultrasonic transducer 1, as shown in FIG. 2, the wiring body 100 is fixed to the lower sealing body 40 with the cover layer 150 facing the piezoelectric element 30 and the base layer 110 positioned on the opposite side of the conductor layer 120 from the piezoelectric element 30.

[0115] As shown in Figures 2 and 6(d), the lower sealing plate 40 has a central opening 42 large enough to integrally surround the multiple (nine in this embodiment) openings 15 in the rigid substrate 10, and is fixed to the upper surface of the flexible resin film 20 so that the central opening 42 integrally surrounds the multiple openings 15 in a plan view.

[0116] As shown in FIG. 2, the lower sealing plate 40 has approximately the same thickness as the piezoelectric element 30, and is fixed to the upper surface of the flexible resin film 20 by adhesive or thermocompression bonding.

[0117] The lower sealing plate 40 is preferably made of a metal such as stainless steel, a carbon fiber reinforced plastic, or a ceramic.

[0118] The lower sealing plate 40 seals the sides of the piezoelectric element group consisting of the plurality of piezoelectric elements 30, and also acts as a base to which the wiring body 100 is fixed.

[0119] 2, in the space surrounded by the central opening 42 of the lower sealing plate 40, the portions on the sides of the plurality of piezoelectric elements 30 are filled with an insulating resin material 50. The insulating resin material 50 is, for example, a flexible resin material such as silicone.

[0120] The provision of the insulating resin material 50 can effectively block external influences on the plurality of piezoelectric elements 30. Furthermore, the vibration damping of the piezoelectric elements 30 can be increased, and the reverberation of the sound waves generated in bursts by the plurality of piezoelectric elements 30 can be suppressed, thereby widening the range in which the distance of an object can be detected by the reflected waves as much as possible.

[0121] 18(a) to 18(c) are plan views respectively showing the upper sealing plate 60, the sound absorbing material 70, and the reinforcing plate 75. In order to facilitate understanding of the relative positional relationship of each component, center lines are drawn in the same positions as in FIGS. 6(a) to 6(d) and 7(a) to 7(e) in plan views.

[0122] 2, the upper sealing plate 60 is fixed to the upper surfaces of the lower sealing plate 40 and the wiring assembly 100 via a flexible resin material 55. As shown in Fig. 2 and Fig. 11(a), the upper sealing plate 60 has a plurality of openings 65 (nine in this embodiment) corresponding to the plurality of piezoelectric elements 30, respectively.

[0123] By providing the upper sealing plate 60, it is possible to stably support the wiring body 100 while minimizing the influence on the flexural vibration of the vibrating body.

[0124] The upper sealing plate 60 is made of, for example, a metal such as stainless steel, carbon fiber reinforced plastic, ceramics, or the like, with a thickness of 0.1 mm to 0.3 mm.

[0125] The sound absorbing material 70 is fixed to the upper surface of the upper sealing plate 60 by adhesive or the like so as to cover the plurality of openings 65 of the upper sealing plate 60 .

[0126] The sound absorbing material 70 is made of, for example, silicone resin or other foamable resin with a thickness of about 0.3 mm to 1.5 mm.

[0127] By providing the sound absorbing material 70, it is possible to effectively prevent the sound waves generated by the piezoelectric element 30 from being emitted in the direction opposite to the intended direction (the lower side in FIG. 2).

[0128] The reinforcing plate 75 is fixed to the upper surface of the sound absorbing material 70 by adhesive or the like.

[0129] The reinforcing plate 75 is made of, for example, a metal such as stainless steel, carbon fiber reinforced plastic, ceramics, or the like, with a thickness of about 0.2 mm to 0.5 mm.

[0130] By providing the reinforcing plate 75, it is possible to prevent external forces from affecting the substrate 10 and the piezoelectric element 30 as much as possible.

[0131] The following describes a manufacturing method of the ultrasonic transducer 1. The manufacturing method includes a rigid substrate forming step of preparing a rigid plate material of the same thickness as the rigid substrate 10 and forming the plurality of openings 15 in the rigid plate material by etching or the like to obtain the rigid substrate 10, and a flexible resin film fixing step of fixing the flexible resin film 20 to the upper surface of the rigid substrate 10 by adhesive or thermocompression bonding so as to cover the plurality of openings 15. Figure 19 shows a vertical cross-sectional view of the pre-assembly after the flexible resin film fixing step.

[0132] In this embodiment, the manufacturing method includes a lower sealing plate fixing step of preparing a lower sealing plate 40 having substantially the same thickness as the piezoelectric element 30 and a central opening 42 large enough to integrally surround the plurality of openings 15 in the rigid substrate 10, and fixing the lower sealing plate 40 to the upper surface of the flexible resin film 20 with an adhesive so that the central opening 42 integrally surrounds the plurality of openings 15 in a plan view. Figure 20 shows a vertical cross-sectional view of the pre-assembly after the lower sealing plate fixing step.

[0133] The manufacturing method further includes a piezoelectric element fixing process in which the plurality of piezoelectric elements 30 are fixed to the upper surface of the flexible resin film 20 using an insulating resin material (not shown) that acts as an adhesive so that they overlap with the plurality of openings 15 in a planar view.

[0134] In this embodiment, the manufacturing method includes an insulating resin filling step of filling an insulating resin material into the space surrounded by the central opening 42 of the lower sealing plate 40, in the side portions of each of the plurality of piezoelectric elements 30. The insulating resin material is preferably a flexible resin material such as silicone resin. Figure 21 shows a vertical cross-sectional view of the pre-assembly after the insulating resin filling step.

[0135] The insulating resin filling process is configured to pour a thermosetting insulating resin material such as silicone resin into the central opening 42 of the lower sealing plate 40 and harden it by heating it at, for example, approximately 100°C to 150°C for several tens of minutes.

[0136] The manufacturing method further includes an insulating cover installation process in which the insulating cover 300A is provided on the upper end surface of the piezoelectric element 30 so as to integrally cover at least a portion of the internal electrode terminal 34T, an internal electrode terminal facing region 362 of the upper surface electrode 36 that faces the internal electrode terminal 34T through the internal electrode side gap 34a, and the region of the internal electrode side gap 34a that is sandwiched between the internal electrode terminal 34T and the internal electrode terminal facing region 362.

[0137] Fig. 22 shows a vertical cross-sectional view of the pre-assembly after the insulating cover installation step. Fig. 23 shows an enlarged view of part XXIII in Fig. 22. Fig. 24 shows a plan view of the piezoelectric element 30 after the insulating cover installation step.

[0138] As shown in Figures 22 to 24, in the manufacturing method, the insulating cover body installation process uses the insulating cover body 300A, but it is also possible to use any of the insulating cover bodies 300B to 300D instead.

[0139] The insulating cover body 300A can be efficiently formed, for example, by applying epoxy resin or silicone resin to a predetermined position using a dispenser or screen printing, and then heating and hardening it at a predetermined temperature (for example, 120°C to 150°C).

[0140] The manufacturing method further includes an electrode exposure process for forming the internal electrode opening 315A (or 315B) in the insulating cover body 300A, exposing at least a portion of the internal electrode terminal 34T while not exposing the internal electrode terminal facing region 362.

[0141] Fig. 25 shows a vertical cross-sectional view of the pre-assembly after the electrode exposing step, Fig. 26 shows an enlarged view of part XXVI in Fig. 25, and Fig. 27 is a plan view of the piezoelectric element 30 after the electrode exposing step.

[0142] As shown in Figure 26, etc., in this embodiment, the electrode exposure process involves irradiating laser light L onto the area of ​​the insulating cover body 300A where the internal electrode opening 315A is to be formed, and peeling off that area of ​​the insulating cover body 300A to form the internal electrode opening 315A.

[0143] Alternatively, the internal electrode openings 315A can be formed by ion beam, electron beam or ion milling.

[0144] When the insulating cover installation step is configured to install the insulating cover 300C (FIGS. 12 and 13) or 300D (FIGS. 14 and 15), the electrode exposure step is configured to form, in addition to the internal electrode opening 315A, the external electrode opening 310A (or 310B) that integrally exposes at least a portion of the lower surface electrode terminal 37T and at least a portion of the upper surface electrode 36. The external electrode opening 310A is formed by the same method as the internal electrode opening 315A.

[0145] The manufacturing method further includes a conductive bonding material setting step of providing a first conductive bonding material 190a so as to integrally cover at least a portion of the lower electrode terminal 37T and at least a portion of a lower electrode terminal opposing region 361 of the upper electrode 36 that faces the lower electrode terminal 37T through the lower electrode side gap 37a, and providing a second conductive bonding material 190b on a portion of the internal electrode terminal 34T that is exposed through the internal electrode opening 315A.

[0146] Fig. 28 shows a vertical cross-sectional view of the pre-assembly after the conductive bonding material providing step, and Fig. 29 shows an enlarged view of part XXIX in Fig. 28.

[0147] In addition, in a configuration in which the insulating cover bodies 300C, 300D are used and the openings 310A, 310B for the external electrodes are formed in the insulating cover bodies 300C, 300D, the first conductive bonding material 190a is provided within the openings 310A, 310B for the external electrodes.

[0148] The manufacturing method further includes a wiring body installation process for installing the wiring body 100 so that a portion of the first wiring 130a contacts the first conductive bonding material 190a and a portion of the second wiring 130b contacts the second conductive bonding material 190b.

[0149] Fig. 30 shows a vertical cross-sectional view of the pre-assembly after the wiring body installation step, and Fig. 31 shows an enlarged view of part XXXI in Fig. 30.

[0150] In this embodiment, the wiring body installation process is configured to fix the wiring body 100 to the lower sealing plate 40 with an insulating adhesive (not shown) so that the portion of the first wiring 130a that straddles the external electrode connection opening 155a contacts the first conductive bonding material 190a and the portion of the second wiring 130b that straddles the internal electrode connection opening 155b contacts the second conductive bonding material 190b.

[0151] The insulating adhesive material that fixes the wiring body 100 to the lower sealing plate 40 can be, for example, a thermosetting insulating adhesive material.

[0152] The first and second conductive bonding materials 190a and 190b may be, for example, a thermosetting conductive adhesive or cream solder, and are applied to predetermined areas by a dispenser, screen printing, transfer, or the like.

[0153] The wiring body installation process includes a process of positioning the wiring body 100 in a predetermined position and then performing a heating process to harden the thermosetting insulating adhesive and the first and second conductive bonding materials 190a, 190b.

[0154] The heating temperature may be about 120° C. to 150° C. if the first and second conductive bonding materials 190a, 190b are thermosetting conductive adhesives, and 230° C. to 260° C. if they are cream solder. In the case of cream solder, it melts when heated and solidifies when cooled from the molten state.

[0155] In the manufacturing method, the lower sealing plate fixing process is performed after the flexible resin film fixing process and before the piezoelectric element fixing process, but the lower sealing plate fixing process can be performed at any timing after the flexible resin film fixing process and before the wiring body installation process.

[0156] Furthermore, in the manufacturing method, the insulating resin material filling process is performed after the piezoelectric element fixing process and before the insulating cover body installation process, but the insulating resin material filling process can be performed at any timing after the lower sealing plate fixing process and the piezoelectric element fixing process and before the wiring body installation process.

[0157] The manufacturing method further includes an upper sealing plate installation step of installing the upper sealing plate 60 after the wiring body installation step.

[0158] The upper sealing plate installation step includes a process of applying a thermosetting flexible resin material such as silicone resin to the upper surface of the wiring body 100, a process of placing the upper sealing plate 60 on the flexible resin material, and a process of curing the flexible resin material by heating, for example, at about 100° C. to 150° C. for several tens of minutes. Fig. 32 shows a vertical cross-sectional view of the pre-assembly after the upper sealing plate installation step.

[0159] The manufacturing method further includes, after the upper sealing plate installation step, a sound absorbing material installation step and a reinforcing plate installation step (see FIG. 2).

[0160] The sound-absorbing material installation process includes a process of applying a thermosetting insulating adhesive to the upper surface of the upper sealing plate 60, a process of placing the sound-absorbing material 70 such as silicone resin or other foamable resin on the thermosetting insulating adhesive, and a process of curing the thermosetting insulating adhesive by heating, for example, at approximately 120°C to 150°C for several tens of minutes.

[0161] The reinforcing plate installation process includes a process of applying a thermosetting insulating adhesive to the upper surface of the sound-absorbing material 70, a process of placing the reinforcing plate 75 on the thermosetting insulating adhesive, and a process of curing the thermosetting insulating adhesive by heating, for example, at approximately 120°C to 150°C for several tens of minutes.

[0162] Embodiment 2 Another embodiment of the ultrasonic transducer according to the present invention will now be described with reference to the accompanying drawings. Fig. 33 shows a partial vertical cross-sectional view of the ultrasonic transducer 2 according to this embodiment. Fig. 34 shows an enlarged view of part XXXIV in Fig. 33. In the drawings, the same members as those in the first embodiment are designated by the same reference numerals, and detailed descriptions thereof will be omitted where appropriate.

[0163] As shown in Figures 33 and 34, the ultrasonic transducer 2 has the rigid substrate 10, the flexible resin film 20, the lower sealing plate 40, the plurality of piezoelectric elements 30, an insulating resin material 350, and the wiring body 100.

[0164] The plurality of piezoelectric elements 30 are arranged on the upper surface of the flexible resin film 20 within the central opening 42 so as to overlap the plurality of openings 15 in a plan view.

[0165] The insulating resin material 350 is interposed between the lower end surfaces of the plurality of piezoelectric elements 30 and the flexible resin film 20 , and is provided so as to cover the outer side surfaces and upper end surfaces of the plurality of piezoelectric elements 30 .

[0166] 34, in this embodiment, the insulating resin material 350 includes a first insulating resin material 360 that fixes the lower end surface of the piezoelectric element 30 to the flexible resin film 20, and a second insulating resin material 370 that covers the outer side surface and upper end surface of the piezoelectric element 30. The second insulating resin material 370 is, for example, a flexible resin material such as silicone.

[0167] As shown in Figure 34 (and Figure 43 below, etc.), the portion of the insulating resin material 350 (the second insulating resin material 370 in this embodiment) covering the upper end surface of the piezoelectric element 30 is provided with the external electrode opening 310A (or 310B) that integrally exposes at least a portion of the lower electrode terminal 37T and at least a portion of the upper electrode 36, and the internal electrode opening 315A (or 315B) that exposes at least a portion of the internal electrode terminal 34T but does not expose the internal electrode terminal opposing region 362.

[0168] As in the ultrasonic transducer 1 of the first embodiment, the wiring body 100 is fixed to the lower sealing plate 40 in a state in which the first wiring 130a is electrically connected via the first conductive bonding material 190a to the lower electrode terminal 37T and the upper electrode 361 exposed by the external electrode opening 310A, and the second wiring 130b is electrically connected via the second conductive bonding material 190b to the internal electrode terminal 34T exposed by the internal electrode opening 315A.

[0169] In this embodiment, the insulating resin material 350 includes the first insulating resin material 360 and the second insulating resin material 370 as described above, but it is also possible to provide an insulating resin material 350B made of a single material instead of the insulating resin material 350. Fig. 35 shows a partially enlarged vertical cross-sectional view of a modified example including the insulating resin material 350B made of a single material.

[0170] A manufacturing method of the ultrasonic transducer 2 will be described below. The manufacturing method includes a rigid substrate forming step of preparing a rigid plate material of the same thickness as the rigid substrate 10 and forming the plurality of openings 15 in the rigid plate material by etching or the like to obtain the rigid substrate 10, and a flexible resin film fixing step of fixing the flexible resin film 20 to the upper surface of the rigid substrate 10 by adhesive or thermocompression bonding so as to cover the plurality of openings 15. Figure 36 shows a vertical cross-sectional view of the pre-assembly after the flexible resin film fixing step.

[0171] In this embodiment, the manufacturing method includes a lower sealing plate fixing step of preparing the lower sealing plate 40 having substantially the same thickness as the piezoelectric element 30 and the central opening 42 of a size sufficient to integrally surround the plurality of openings 15 in the rigid substrate 10, and fixing the lower sealing plate 40 to the upper surface of the flexible resin film 20 with an adhesive so that the central opening 42 integrally surrounds the plurality of openings 15 in a plan view. Figure 37 shows a vertical cross-sectional view of the pre-assembly after the lower sealing plate fixing step.

[0172] The manufacturing method further includes a piezoelectric element fixing step of fixing the plurality of piezoelectric elements 30 to the upper surface of the flexible resin film 20 with a first insulating resin material 360 so as to overlap the plurality of openings 15 in a plan view. Figure 38 shows a vertical cross-sectional view of the pre-assembly after the piezoelectric element fixing step.

[0173] The order of the lower sealing plate fixing step and the piezoelectric element fixing step may be reversed, i.e., the piezoelectric element fixing step may be performed first, and then the lower sealing plate fixing step may be performed.

[0174] The manufacturing method further includes an insulating resin material installation process in which a second insulating resin material 370 is provided within the central opening 42 so as to cover the outer surfaces of the plurality of piezoelectric elements 30 and to cover the upper end surfaces of the plurality of piezoelectric elements 30 to form an insulating cover body 300E.

[0175] Fig. 39 shows a vertical cross-sectional view after the insulating resin material applying step, Fig. 40 shows an enlarged view of the XXXX portion in Fig. 39, and Fig. 41 shows a plan view of the piezoelectric element 30 after the insulating resin material applying step.

[0176] The second insulating resin material 370 is preferably a flexible resin material such as silicone resin. The insulating resin material applying step is configured to apply a thermosetting insulating resin material such as silicone resin so as to cover the upper end surfaces and outer side surfaces of the plurality of piezoelectric elements 30, and then heat-treat the resin material at, for example, about 100°C to 150°C for several tens of minutes to harden the resin material.

[0177] The manufacturing method further includes an electrode exposing step of forming, in the insulating cover body 300E, the external electrode opening 310A that integrally exposes at least a portion of the lower surface electrode terminal 37T and at least a portion of the upper surface electrode 36, and the internal electrode opening 315A that exposes at least a portion of the internal electrode terminal 34T but does not expose the internal electrode terminal facing region 362.

[0178] Fig. 42 shows a partially enlarged vertical cross-sectional view of the pre-assembly after the electrode exposing step, and Fig. 43 shows a plan view of the piezoelectric element 30 after the electrode exposing step.

[0179] As shown in Figure 42, in this embodiment, the electrode exposure process involves irradiating laser light L onto the area of ​​the insulating cover body 300E where the external electrode opening 310A and the internal electrode opening 315A are to be formed, and peeling off those areas of the insulating cover body 300E to form the external electrode opening 310A and the internal electrode opening 315A.

[0180] Alternatively, the external electrode opening 310A and the internal electrode opening 315A can be formed by ion beam, electron beam, or ion milling.

[0181] The manufacturing method further includes a conductive bonding material installation process in which a first conductive bonding material 190a is provided to integrally cover the portions of the lower electrode terminal 37T and the upper electrode 36 that are exposed through the external electrode opening 310A, and a second conductive bonding material 190b is provided on the portion of the internal electrode terminal 34T that is exposed through the internal electrode opening 315A.

[0182] Fig. 44 shows a vertical cross-sectional view of the pre-assembly after the conductive bonding material providing step, and Fig. 45 shows an enlarged view of part XXXXV in Fig. 44.

[0183] The manufacturing method further includes a wiring body installation process for installing the wiring body 100 so that a portion of the first wiring 130a contacts the first conductive bonding material 190a and a portion of the second wiring 130b contacts the second conductive bonding material 190b.

[0184] Fig. 46 shows a vertical cross section of the pre-assembly after the wiring body installation step, and Fig. 47 shows an enlarged view of part XXXXVII in Fig. 46.

[0185] In this embodiment, the wiring body installation process is configured to fix the wiring body 100 to the lower sealing plate 40 with an insulating adhesive so that the portion of the first wiring 130a that straddles the external electrode connection opening 155a contacts the first conductive bonding material 190a and the portion of the second wiring 130b that straddles the internal electrode connection opening 155b contacts the second conductive bonding material 190b.

[0186] The insulating adhesive material that fixes the wiring body 100 to the lower sealing plate 40 can be, for example, a thermosetting insulating adhesive material.

[0187] The first and second conductive bonding materials 190a and 190b may be, for example, a thermosetting conductive adhesive or cream solder, and are applied to predetermined areas by a dispenser, screen printing, transfer, or the like.

[0188] The wiring body installation process includes a process of positioning the wiring body in a predetermined position and then performing a heating process to harden the thermosetting insulating adhesive and the first and second conductive bonding materials 190a, 190b.

[0189] The heating temperature may be about 120° C. to 150° C. if the first and second conductive bonding materials 190a, 190b are thermosetting conductive adhesives, and 230° C. to 260° C. if they are cream solder. In the case of cream solder, it melts when heated and solidifies when cooled from the molten state.

[0190] The manufacturing method further includes an upper sealing plate installation step of installing the upper sealing plate 60 after the wiring body installation step.

[0191] The upper sealing plate installation step includes a process of applying a thermosetting flexible resin material such as silicone resin to the upper surface of the wiring body 100, a process of placing the upper sealing plate 60 on the flexible resin material, and a process of curing the flexible resin material by heating, for example, at about 100° C. to 150° C. for several tens of minutes. Fig. 48 shows a vertical cross-sectional view of the pre-assembly after the upper sealing plate installation step.

[0192] The manufacturing method further includes, after the upper sealing plate installation step, a sound absorbing material installation step and a reinforcing plate installation step (see FIG. 2).

[0193] The sound-absorbing material installation process includes a process of applying a thermosetting insulating adhesive to the upper surface of the upper sealing plate 60, a process of placing the sound-absorbing material 70 such as silicone resin or other foamable resin on the thermosetting insulating adhesive, and a process of curing the thermosetting insulating adhesive by heating, for example, at approximately 120°C to 150°C for several tens of minutes.

[0194] The reinforcing plate installation process includes a process of applying a thermosetting insulating adhesive to the upper surface of the sound-absorbing material 70, a process of placing the reinforcing plate 75 on the thermosetting insulating adhesive, and a process of curing the thermosetting insulating adhesive by heating, for example, at approximately 120°C to 150°C for several tens of minutes.

[0195] In the manufacturing method, the insulating resin material (the first insulating resin material 360) that fixes the piezoelectric element 30 to the flexible resin film 20 and the insulating resin material (the second insulating resin material 370) that covers the upper end surface of the piezoelectric element 30 and forms the insulating cover body 300E are different, but it is also possible to form them from a single material.

[0196] The manufacturing method according to this modification is configured so that, after the flexible resin film fixing step, a lower sealing plate installation step, an insulating resin filling step, and a piezoelectric element fixing step are performed in this order.

[0197] The lower sealing plate installation process is configured to prepare a lower sealing plate 40B that is thicker than the piezoelectric element 30 and has a central opening 42 large enough to surround all of the plurality of openings 15 in a planar view, and to fix the lower sealing plate 40B to the upper surface of the flexible resin film 20 so that the central opening 42 surrounds all of the plurality of openings 15.

[0198] The insulating resin filling step is configured to fill the central opening 42 with an insulating resin material 380. The insulating resin material 380 is, for example, a thermosetting type. Figure 49 shows a vertical cross-sectional view of the pre-assembly after the insulating resin filling step.

[0199] Fig. 50 shows a vertical cross-sectional view of the pre-assembly after the piezoelectric element fixing step, and Fig. 51 shows an enlarged view of part XXXXXI in Fig. 50.

[0200] As shown in Figures 50 and 51, the piezoelectric element fixing process is configured to place the multiple piezoelectric elements 30 on the upper surface of the flexible resin film 20 in the insulating resin material 380 in an uncured state so that a portion of the insulating resin material 380 covers the upper end surfaces of the piezoelectric elements 30 and overlaps with each of the multiple openings 15 in a planar view, and then fix the multiple piezoelectric elements 30 to the flexible resin film 20 by curing the insulating resin material 380, and form an insulating cover body 300E on the upper end surfaces of the piezoelectric elements 30.

[0201] Preferably, the amount of insulating resin material 380 filled in the piezoelectric element fixing process is adjusted so that, when the piezoelectric element 300 is placed on the upper surface of the flexible resin film 20, as shown in Figure 51, it covers the peripheral region of the upper end surface of the piezoelectric element 30, including at least a part of the internal electrode terminal 34T, the internal electrode terminal opposing region 362 of the upper surface electrode 36 that faces the internal electrode terminal 34T via the internal electrode side gap 34a, and the region of the internal electrode side gap 34a sandwiched between the internal electrode terminal 34T and the internal electrode terminal opposing region 362, while not covering the central region of the upper end surface of the piezoelectric element.

[0202] According to this preferred configuration, it is possible to effectively prevent or reduce adhesion of the insulating resin material 380 to the pick nozzle when mounting the piezoelectric element 30, and the mounting work of the piezoelectric element 30 can be performed accurately and efficiently.

[0203] In the manufacturing method according to the modified example, after the piezoelectric element fixing step, the same steps as in the manufacturing method according to the present embodiment are carried out.

[0204] In the first and second embodiments, as shown in FIG. 8( a) and the like, the piezoelectric element 30 has the lower electrode terminal 37T and the internal electrode terminal 34T disposed midway along one side and the other side that form the outer shape in a plan view, respectively; however, the present invention is not limited to such a configuration.

[0205] 52 shows a plan view of a piezoelectric element 30B according to another embodiment of the present invention, which is provided with the insulating cover body 300A. The piezoelectric element 30B has the lower electrode terminals 37T and the internal electrode terminals 34T arranged at the corners of a rectangular shape in a plan view.

[0206] Furthermore, in the first and second embodiments, the lower sealing plate 40 is used, but in the present invention, the lower sealing plate 40 can be replaced with a lower sealing plate 40B.

[0207] Fig. 53 shows a plan view of the lower sealing plate 40B. Fig. 54 shows a partial vertical cross-sectional view of an ultrasonic transducer 1B according to a modification of the first embodiment, in which the lower sealing plate 40B is used instead of the lower sealing plate 40.

[0208] As shown in FIGS. 53 and 54, the lower sealing plate 40B has partition walls 45 that divide the central opening 42 into a plurality of openings 43 each large enough to surround one of the piezoelectric elements 30.

[0209] REFERENCE SIGNS LIST 1, 1B, 2 Ultrasonic transducer 10 Rigid substrate 15 Opening 20 Flexible resin film 30, 30B Piezoelectric element 32 Piezoelectric element body 34 Internal electrode 34a Internal electrode side gap 34T Internal electrode terminal 35 Internal electrode connector 36 Upper electrode (external electrode) 37 Lower electrode (external electrode) 37a Lower electrode side gap 37T Lower electrode terminal 38 Lower electrode connector 40, 40B Lower sealing plate 42 Central opening 45 Partition wall 100 Wiring body 110 Insulating base layer 111 Base-side piezoelectric element overlapping portion 112a External electrode tab region 112b Internal electrode tab region 115a First access opening 115b Second access opening 116 Base-side tip portion 130a, 130b First wiring, second wiring 150 Insulating cover layer 151 Cover-side piezoelectric element overlapping portion 152a External electrode tab region 152b Internal electrode tab region 155a External electrode connection opening 155b Internal electrode connection opening 156 Cover-side tip portion 190a First conductive bonding material 190b Second conductive bonding material 300A to 300D Insulating cover body 310A, 310B External electrode opening 315A, 315B Internal electrode opening 350, 350B Insulating resin material 360 First insulating resin material 361 Lower surface electrode terminal facing region 362 Internal electrode terminal facing region 370 Second insulating resin material

Claims

1. A piezoelectric element body formed of a piezoelectric material; an upper surface electrode and a lower surface electrode which are provided on an upper end surface and a lower end surface of the piezoelectric element body, respectively, and which form external electrodes; an internal electrode that divides the piezoelectric element body into upper and lower parts in the thickness direction; a lower electrode connector, the lower electrode terminal being formed on the upper end surface of the piezoelectric element body with a base end side electrically connected to the lower electrode and a tip end side being provided between the lower electrode and the upper electrode with a lower electrode side gap; an internal electrode connector, the internal electrode terminal being provided on the upper end surface of the piezoelectric element body with a base end side electrically connected to the internal electrode and a tip end side being provided between the base end side and the upper surface electrode with an internal electrode side gap; an insulating cover body that integrally covers at least a portion of the internal electrode terminal, an internal electrode terminal facing region of the upper surface electrode that faces the internal electrode terminal across the internal electrode side gap, and a region of the internal electrode side gap that is sandwiched between the internal electrode terminal and the internal electrode terminal facing region, a first insulating cover provided with an opening for an internal electrode that exposes at least a portion of the internal electrode terminal while not exposing a region facing the internal electrode terminal;

2. 2. The multi-layer piezoelectric element according to claim 1, wherein the internal electrode opening is configured to expose a region of the internal electrode side gap adjacent to an exposed region of the internal electrode terminal.

3. 2. The multi-layer piezoelectric element according to claim 1, wherein the internal electrode opening is configured so as not to expose the internal electrode side gap.

4. the insulating cover body is configured to integrally cover at least a portion of the lower electrode terminal, a lower electrode terminal facing region of the upper electrode that faces the lower electrode terminal across the lower electrode side gap, and a region of the lower electrode side gap that is sandwiched between the lower electrode terminal and the lower electrode terminal facing region, 4. The multilayer piezoelectric element according to claim 1, wherein the insulating cover body is provided with, in addition to the internal electrode opening, an external electrode opening that integrally exposes at least a portion of the lower electrode terminal and at least a portion of the upper electrode.

5. 5. The multi-layer piezoelectric element according to claim 4, wherein the insulating cover is configured to cover the entire upper end surface of the piezoelectric element body in a plan view.

6. 5. The multi-layer piezoelectric element according to claim 4, wherein the insulating cover is configured to cover a part of an upper end surface of the piezoelectric element body in a plan view.

7. The present invention relates to a method for manufacturing a piezoelectric element, the method comprising: providing a rigid substrate having a plurality of openings penetrating between an upper surface and a lower surface; a flexible resin film fixed to the upper surface of the substrate so as to cover the plurality of openings; piezoelectric elements, the number of which is equal to the number of the plurality of openings, fixed to the flexible resin film so that a central region overlaps with a corresponding opening and a peripheral region overlaps with the upper surface of the substrate in a plan view; and a wiring body having first and second wirings electrically connected to external and internal electrodes of the piezoelectric elements, respectively. The piezoelectric elements include a piezoelectric element body formed of a piezoelectric material, and a wiring body having first and second wirings provided on the upper end surface and the lower surface of the lower end surface of the piezoelectric element body, the wiring body having first and second wirings electrically connected to the external electrodes and the internal electrodes of the piezoelectric elements, a lower electrode connector that is provided on the upper end surface of the piezoelectric element body with a lower electrode side gap between its base end side and the upper electrode side to form a lower electrode terminal; and an internal electrode connector that is provided on the upper end surface of the piezoelectric element body with a base end side electrically connected to the internal electrode and a lower electrode side gap between its tip end side and the upper electrode side to form an internal electrode terminal, a rigid substrate forming step of preparing a rigid plate having the same thickness as the rigid substrate and forming the plurality of openings in the rigid plate to form the rigid substrate; a flexible resin film fixing step of fixing the flexible resin film to an upper surface of the rigid substrate so as to cover the plurality of openings; a piezoelectric element fixing step of fixing the plurality of piezoelectric elements to the upper surface of the flexible resin film with an insulating adhesive so as to overlap the plurality of openings in a plan view; an insulating cover installation step of providing an insulating cover on the upper end surface of the piezoelectric element so as to integrally cover at least a portion of the internal electrode terminal, an internal electrode terminal facing region of the upper surface electrode that faces the internal electrode terminal across the internal electrode side gap, and a region of the internal electrode side gap that is sandwiched between the internal electrode terminal and the internal electrode terminal facing region; an electrode exposing step of forming an internal electrode opening in the insulating cover body, the internal electrode opening exposing at least a part of the internal electrode terminal while not exposing a region facing the internal electrode terminal; a conductive bonding material providing step of providing a first conductive bonding material so as to integrally cover at least a portion of the lower electrode terminal and at least a portion of a lower electrode terminal facing region of the upper electrode that faces the lower electrode terminal through the lower electrode side gap, and providing a second conductive bonding material on a portion of the internal electrode terminal that is exposed through the internal electrode opening; A method for manufacturing an ultrasonic transducer, comprising: a wiring body installation process for installing the wiring body so that a portion of the first wiring contacts the first conductive bonding material and a portion of the second wiring contacts the second conductive bonding material.

8. The method for manufacturing an ultrasonic transducer according to claim 7, characterized in that the electrode exposure process is configured to form the internal electrode opening by irradiating a laser light onto an area of ​​the insulating cover body where the internal electrode opening is to be formed.

9. The method for manufacturing an ultrasonic transducer as described in claim 7, characterized in that the insulating cover body is configured not to cover at least a portion of the lower electrode terminal, a lower electrode terminal facing area of ​​the upper electrode that faces the lower electrode terminal through the lower electrode side gap, and an area of ​​the lower electrode side gap that is sandwiched between the lower electrode terminal and the lower electrode terminal facing area.

10. the insulating cover body is configured to integrally cover at least a portion of the lower electrode terminal, a lower electrode terminal facing region of the upper electrode that faces the lower electrode terminal across the lower electrode side gap, and a region of the lower electrode side gap that is sandwiched between the lower electrode terminal and the lower electrode terminal facing region, the electrode exposing step is configured to form an external electrode opening that integrally exposes at least a portion of the lower surface electrode terminal and at least a portion of the upper surface electrode in addition to the internal electrode opening; The method for manufacturing an ultrasonic transducer according to claim 7, wherein the conductive bonding material providing step is configured to provide the first conductive bonding material in the external electrode opening.

11. a lower sealing plate fixing step of preparing a lower sealing plate having substantially the same thickness as the piezoelectric element and a central opening of a size sufficient to integrally surround the plurality of openings in the rigid substrate, and fixing the lower sealing plate to the upper surface of the flexible resin film such that the central opening integrally surrounds the plurality of openings in a plan view; the lower sealing plate fixing step is performed at an arbitrary timing after the flexible resin film fixing step and before the wiring body installation step; 11. The method for manufacturing an ultrasonic transducer according to claim 7, wherein the wiring body installation step is configured to place the wiring body on the lower sealing plate.

12. The method for manufacturing an ultrasonic transducer as described in claim 11, characterized in that after the lower sealing plate fixing process and the piezoelectric element fixing process and before the wiring body installation process, an insulating resin filling process is provided in which an insulating resin material is filled into each side portion of the plurality of piezoelectric elements in the space surrounded by the central opening of the lower sealing plate.

13. The method for manufacturing an ultrasonic transducer according to claim 11, wherein the lower sealing plate has partitions that divide the central opening into a plurality of openings each large enough to surround one of the piezoelectric elements.

14. a rigid substrate having a plurality of openings extending therethrough between an upper surface and a lower surface; a flexible resin film fixed to an upper surface of the substrate so as to cover the plurality of openings; a lower sealing plate having a central opening of a size sufficient to surround all of the plurality of openings in a plan view, the lower sealing plate being fixed to the upper surface of the flexible resin film such that the central opening surrounds all of the plurality of openings; a plurality of piezoelectric elements arranged on an upper surface of the flexible resin film within the central opening so as to overlap with the plurality of openings in a plan view; an insulating resin material that fixes the plurality of piezoelectric elements at their respective positions; a wiring body having first and second wirings and fixed to an upper surface of the lower sealing plate; the piezoelectric element comprises a piezoelectric element body formed of a piezoelectric material, an upper surface electrode and a lower surface electrode respectively provided on an upper end surface and a lower end surface of the piezoelectric element body and forming external electrodes, an internal electrode dividing the piezoelectric element body into upper and lower portions in the thickness direction, a lower surface electrode connector provided on the upper end surface of the piezoelectric element body with a base end side electrically connected to the lower surface electrode and a tip end side with a lower surface electrode side gap existing between the upper surface electrode and forming a lower surface electrode terminal, and an internal electrode connector provided on the upper end surface of the piezoelectric element body with a base end side electrically connected to the internal electrode and a tip end side with an internal electrode side gap existing between the upper surface electrode and forming an internal electrode terminal, the insulating resin material is interposed between lower end surfaces of the plurality of piezoelectric elements and the flexible resin film, and is provided so as to cover outer surfaces and upper end surfaces of the plurality of piezoelectric elements; a portion of the insulating resin material that covers an upper end surface of the piezoelectric element to form an insulating cover body, the portion having an external electrode opening that integrally exposes at least a portion of the lower electrode terminal and at least a portion of the upper electrode, and an internal electrode opening that exposes at least a portion of the internal electrode terminal but does not expose an internal electrode terminal facing region of the upper electrode that faces the internal electrode terminal through the internal electrode side gap, the first wiring is electrically connected to the lower surface electrode terminal and the upper surface electrode exposed by the external electrode opening via a first conductive bonding material; The ultrasonic transducer according to claim 1, wherein the second wiring is electrically connected to the internal electrode terminal exposed by the internal electrode opening via a second conductive bonding material.

15. The piezoelectric element assembly of claim 14, characterized in that the insulating resin material includes a first insulating resin material that adheres the lower end surfaces of the plurality of piezoelectric elements to the flexible resin film, and a second insulating resin material that covers the outer surfaces and upper end surfaces of the plurality of piezoelectric elements.

16. 15. The piezoelectric element assembly according to claim 14, wherein the insulating resin material is a single material.

17. 15. The ultrasonic transducer according to claim 14, wherein the lower sealing plate has partitions that divide the central opening into a plurality of openings each having a size sufficient to surround one of the piezoelectric elements.

18. the wiring body includes an insulating base layer that supports the first and second wirings, and an insulating cover layer that covers at least a portion of the first and second wirings from the side opposite to the base layer, the base layer and the cover layer each have a plurality of piezoelectric element overlapping portions that are partially overlapped with each of the plurality of piezoelectric elements in a plan view, and a tip portion that integrally holds the plurality of piezoelectric element overlapping portions; a piezoelectric element overlapping portion of a piezoelectric element-side insulating layer located on a side of the base layer and the cover layer facing the piezoelectric element includes an external electrode tab region overlapping in a plan view with a region integrally surrounding at least a portion of the lower electrode terminal and at least a portion of the lower electrode terminal facing region, the external electrode tab region having an external electrode connection opening, and an internal electrode tab region overlapping in a plan view with at least a portion of the internal electrode terminal, the internal electrode tab region having an internal electrode connection opening; a portion of the first wiring straddles the external electrode connection opening, and a portion of the second wiring straddles the internal electrode connection opening, the wiring body is fixed to the upper surface of the lower sealing plate in a state in which the external electrode connection opening overlaps, in a plan view, a region integrally including at least a portion of the lower electrode terminal and at least a portion of the lower electrode facing region, and the internal electrode connection opening overlaps, in a plan view, at least a portion of the internal electrode terminal; a portion of the first wiring that spans the external electrode connection opening is bonded to the first conductive bonding material; 18. The piezoelectric element assembly according to claim 14, wherein a portion of the second wiring that straddles the internal electrode connection opening is bonded to the second conductive bonding material.

19. The piezoelectric element assembly of claim 18, characterized in that the piezoelectric element overlapping portion of the insulating layer located on the side of the base layer and the cover layer that is away from the piezoelectric element includes an external electrode tab region that overlaps in a planar view with a region that integrally surrounds at least a portion of the lower electrode terminal and at least a portion of the lower electrode terminal opposing region, the external electrode tab region having a first access opening, and an internal electrode tab region that overlaps in a planar view with at least a portion of the internal electrode terminal, the second tab region having a second access opening.

20. The present invention relates to a method for manufacturing a piezoelectric element, the method comprising: providing a rigid substrate having a plurality of openings penetrating between an upper surface and a lower surface; a flexible resin film fixed to the upper surface of the substrate so as to cover the plurality of openings; piezoelectric elements, the number of which is equal to the number of the plurality of openings, fixed to the flexible resin film so that a central region overlaps with a corresponding opening and a peripheral region overlaps with the upper surface of the substrate in a plan view; and a wiring body having first and second wirings electrically connected to external and internal electrodes of the piezoelectric elements, respectively. The piezoelectric elements each include a piezoelectric element body formed of a piezoelectric material, and a wiring body having first and second wirings provided on the upper and lower end surfaces of the piezoelectric element body, the wiring body having first and second wirings electrically connected to the external electrodes and internal electrodes of the piezoelectric elements. a lower electrode connector that is provided on the upper end surface of the piezoelectric element body with a lower electrode side gap between its base end side and the upper electrode side to form a lower electrode terminal; and an internal electrode connector that is provided on the upper end surface of the piezoelectric element body with a base end side electrically connected to the internal electrode and a lower electrode side gap between its tip end side and the upper electrode side to form an internal electrode terminal, the method comprising the steps of: a rigid substrate forming step of preparing a rigid plate having the same thickness as the rigid substrate and forming the plurality of openings in the rigid plate to form the rigid substrate; a flexible resin film fixing step of fixing the flexible resin film to an upper surface of the rigid substrate so as to cover the plurality of openings; a lower sealing plate installation step of preparing a lower sealing plate having a central opening large enough to surround all of the plurality of openings in a plan view, and adhering the lower sealing plate to an upper surface of the flexible resin film so that the central opening surrounds all of the plurality of openings; a piezoelectric element fixing step of fixing the plurality of piezoelectric elements to the upper surface of the flexible resin film by a first insulating resin material so as to overlap the plurality of openings in a plan view; an insulating resin material providing step of providing a second insulating resin material in the central opening so as to cover outer side surfaces of the plurality of piezoelectric elements and to cover upper end surfaces of the plurality of piezoelectric elements to form an insulating cover body; an electrode exposing step of forming, in the insulating cover body, an external electrode opening that integrally exposes at least a part of the lower surface electrode terminal and at least a part of the upper surface electrode, and an internal electrode opening that exposes at least a part of the internal electrode terminal but does not expose a region facing the internal electrode terminal; a conductive bonding material providing step of providing a first conductive bonding material so as to integrally cover the lower surface electrode terminal and the upper surface electrode, the portions of which are exposed through the external electrode opening, and providing a second conductive bonding material on the portion of the internal electrode terminal, the portions of which are exposed through the internal electrode opening; A method for manufacturing an ultrasonic transducer, comprising: a wiring body installation process for installing the wiring body so that a portion of the first wiring contacts the first conductive bonding material and a portion of the second wiring contacts the second conductive bonding material.

21. The present invention relates to a method for manufacturing a piezoelectric element, the method comprising: providing a rigid substrate having a plurality of openings penetrating between an upper surface and a lower surface; a flexible resin film fixed to the upper surface of the substrate so as to cover the plurality of openings; piezoelectric elements, the number of which is equal to the number of the plurality of openings, fixed to the flexible resin film so that a central region overlaps with a corresponding opening and a peripheral region overlaps with the upper surface of the substrate in a plan view; and a wiring body having first and second wirings electrically connected to external and internal electrodes of the piezoelectric elements, respectively. The piezoelectric elements each include a piezoelectric element body formed of a piezoelectric material, and a wiring body having first and second wirings provided on the upper and lower end surfaces of the piezoelectric element body, the wiring body having first and second wirings electrically connected to the external electrodes and internal electrodes of the piezoelectric elements. a lower electrode connector that is provided on the upper end surface of the piezoelectric element body with a lower electrode side gap between its base end side and the upper electrode side to form a lower electrode terminal; and an internal electrode connector that is provided on the upper end surface of the piezoelectric element body with a base end side electrically connected to the internal electrode and a lower electrode side gap between its tip end side and the upper electrode side to form an internal electrode terminal, the method comprising the steps of: a rigid substrate forming step of preparing a rigid plate having the same thickness as the rigid substrate and forming the plurality of openings in the rigid plate to form the rigid substrate; a flexible resin film fixing step of fixing the flexible resin film to an upper surface of the rigid substrate so as to cover the plurality of openings; a piezoelectric element fixing step of fixing the plurality of piezoelectric elements to the upper surface of the flexible resin film by a first insulating resin material so as to overlap the plurality of openings in a plan view; a lower sealing plate installation step of preparing a lower sealing plate having a central opening large enough to surround all of the plurality of openings in a plan view, and adhering the lower sealing plate to an upper surface of the flexible resin film so that the central opening surrounds all of the plurality of openings; an insulating resin material providing step of providing a second insulating resin material in the central opening so as to cover outer side surfaces of the plurality of piezoelectric elements and to cover upper end surfaces of the plurality of piezoelectric elements to form an insulating cover body; an electrode exposing step of forming, in the insulating cover body, an external electrode opening that integrally exposes at least a part of the lower surface electrode terminal and at least a part of the upper surface electrode, and an internal electrode opening that exposes at least a part of the internal electrode terminal but does not expose a region facing the internal electrode terminal; a conductive bonding material providing step of providing a first conductive bonding material so as to integrally cover the lower surface electrode terminal and the upper surface electrode, the portions of which are exposed through the external electrode opening, and providing a second conductive bonding material on the portion of the internal electrode terminal, the portions of which are exposed through the internal electrode opening; A method for manufacturing an ultrasonic transducer, comprising: a wiring body installation process for installing the wiring body so that a portion of the first wiring contacts the first conductive bonding material and a portion of the second wiring contacts the second conductive bonding material.

22. The present invention relates to a method for manufacturing a piezoelectric element, the method comprising: providing a rigid substrate having a plurality of openings penetrating between an upper surface and a lower surface; a flexible resin film fixed to the upper surface of the substrate so as to cover the plurality of openings; piezoelectric elements, the number of which is equal to the number of the plurality of openings, fixed to the flexible resin film so that a central region overlaps with a corresponding opening and a peripheral region overlaps with the upper surface of the substrate in a plan view; and a wiring body having first and second wirings electrically connected to external and internal electrodes of the piezoelectric elements, respectively. The piezoelectric elements each include a piezoelectric element body formed of a piezoelectric material, and a wiring body having first and second wirings provided on the upper and lower end surfaces of the piezoelectric element body, the wiring body having first and second wirings electrically connected to the external electrodes and internal electrodes of the piezoelectric elements. a lower electrode connector that is provided on the upper end surface of the piezoelectric element body with a lower electrode side gap between its base end side and the upper electrode side to form a lower electrode terminal; and an internal electrode connector that is provided on the upper end surface of the piezoelectric element body with a base end side electrically connected to the internal electrode and a lower electrode side gap between its tip end side and the upper electrode side to form an internal electrode terminal, the method comprising the steps of: a rigid substrate forming step of preparing a rigid plate having the same thickness as the rigid substrate and forming the plurality of openings in the rigid plate to form the rigid substrate; a flexible resin film fixing step of fixing the flexible resin film to an upper surface of the rigid substrate so as to cover the plurality of openings; a lower sealing plate installation process for preparing a lower sealing plate having a thickness greater than that of the piezoelectric element and a central opening of a size sufficient to surround all of the plurality of openings in a plan view, and adhering the lower sealing plate to an upper surface of the flexible resin film such that the central opening surrounds all of the plurality of openings; an insulating resin filling step of filling the central opening with an insulating resin material; a piezoelectric element fixing process for placing the plurality of piezoelectric elements on the upper surface of the flexible resin film in the insulating resin material so that the plurality of piezoelectric elements overlap with the plurality of openings in a plan view with a portion of the insulating resin material covering the upper end surfaces of the piezoelectric elements, and fixing the plurality of piezoelectric elements to the flexible resin film by the insulating resin material; an electrode exposing step of forming an external electrode opening that integrally exposes at least a part of the lower electrode terminal and at least a part of the upper electrode in a portion of the insulating resin material that covers the upper end surface of the piezoelectric element and forms an insulating cover body, and an internal electrode opening that exposes at least a part of the internal electrode terminal but does not expose a region facing the internal electrode terminal; a conductive bonding material providing step of providing a first conductive bonding material so as to integrally cover the lower surface electrode terminal and the upper surface electrode, the portions of which are exposed through the external electrode opening, and providing a second conductive bonding material on the portion of the internal electrode terminal, the portions of which are exposed through the internal electrode opening; A method for manufacturing an ultrasonic transducer, comprising: a wiring body installation process for installing the wiring body so that a portion of the first wiring contacts the first conductive bonding material and a portion of the second wiring contacts the second conductive bonding material.

23. The method for manufacturing an ultrasonic transducer described in any one of claims 20 to 22, characterized in that the electrode exposure process is configured to form the opening for the external electrode and the opening for the internal electrode by irradiating laser light to an area of ​​the insulating cover body where the opening for the external electrode is to be formed and an area where the opening for the internal electrode is to be formed.

24. A method for manufacturing an ultrasonic transducer as described in any one of claims 20 to 22, characterized in that the lower sealing plate has a partition wall that divides the central opening into multiple openings each large enough to surround one of the piezoelectric elements.