Ultrasonic transducer device, probe, electronic instrument, and ultrasonic diagnostic device

An ultrasonic transducer device includes a base, a plurality of piezoelectric elements, a conductive body and an insulating film. The base has a plurality of vibrating film portions arranged in an array pattern. The piezoelectric elements are respectively disposed on the vibrating film portions. The conductive body is disposed on the base, and arranged inside and outside of an area corresponding to each of the vibrating film portions in a plan view as viewed along a thickness direction of the base. The insulating film is disposed on the conductive body only at outside of the area corresponding to each of the vibrating film portions in the plan view.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application Nos. 2013-071581 filed on Mar. 29, 2013 and 2014-058149 filed on Mar. 20, 2014. The entire disclosure of Japanese Patent Application Nos. 2013-071581 and 2014-058149 is hereby incorporated herein by reference.

BACKGROUND

Technical Field

The present invention relates to an ultrasonic device as well as a probe, electronic instrument, ultrasonic image device and the like that uses that.

Related Art

Ultrasonic transducer devices are generally known. For example, with the ultrasonic transducer device noted in Japanese Unexamined Patent Publication No. 2005-51688, a plurality of vibrating films are provided in an array pattern. A piezoelectric element is formed on the vibrating film. The piezoelectric element is covered by a protective film. The protective film expands with an even thickness on the inside area and the outside area of the vibrating film.

SUMMARY

The ultrasonic waves act on the vibrating film. The ultrasonic waves cause ultrasonic vibration of the vibrating film. Current is output from the piezoelectric element according to the ultrasonic vibration of the vibrating film. In this way, the ultrasonic transducer device detects ultrasonic waves. At this time, when the protective film expands uniformly with an even thickness continuously on the inside area and the outside area of the vibrating film, the flexibility of the vibrating film is reduced. The detection sensitivity of the ultrasonic waves decreases.

According to at least one aspect of the present invention, it is possible to provide an ultrasonic transducer device that realizes protection of a conductive body while maintaining good flexibility of the vibrating film.

An ultrasonic transducer device according to one aspect includes a base, a plurality of piezoelectric elements, a conductive body, a first insulating film and a second insulating film. The base has a plurality of vibrating film portions arranged in an array pattern. The piezoelectric elements are respectively disposed on the vibrating film portions. The conductive body is disposed on the base, and arranged inside and outside of an area corresponding to each of the vibrating film portions in a plan view as viewed along a thickness direction of the base. The first insulating film is disposed on the conductive body only at outside of the area corresponding to each of the vibrating film portions in the plan view. The second insulating film having a film thickness smaller than a film thickness of the first insulating film, and disposed at least partially on each of the piezoelectric elements and only at inside of the area corresponding to each of the vibrating film portions in the plan view.

Ultrasonic waves act on the vibrating film. Ultrasonic waves cause ultrasonic vibration of the vibrating film. Current is output from the piezoelectric element according to the ultrasonic vibration of the vibrating film. In this way, the ultrasonic transducer device detects ultrasonic waves. Here, the first insulating film protects the conductive body. Since the first insulating film does not affect the vibrating film, good flexibility of the vibrating film is maintained.

The ultrasonic transducer device as described above preferably further includes a third insulating film having a film thickness smaller than the film thickness of the second insulating film, and connected to the first insulating film and the second insulating film. In this way, the conductive body can be even more reliably protected. The third insulating film is thinner than the first and second insulating films, so it is possible to maintain the vibrating film vibration operation well.

In the ultrasonic transducer device as described above, each of the piezoelectric elements preferably includes a first electrode disposed on the vibrating film portion, a piezoelectric film covering at least a portion of the first electrode, and a second electrode covering at least a portion of the piezoelectric film. The conductive body preferably includes a first conductive body part connected to the first electrode of each of the piezoelectric elements, and a second conductive body part connected to the second electrode of each of the piezoelectric elements. And the ultrasonic transducer device preferably further includes a fourth insulating film covering a portion of the piezoelectric film that is not covered by the second electrode or the second conductive body part.

In the ultrasonic transducer device as described above, the fourth insulating film preferably includes two sections that sandwich the second electrode from both sides of the second electrode.

In the ultrasonic transducer device as described above, the piezoelectric film preferably covers at least a portion of the first electrode and a portion of a corresponding one of the vibrating film portions, and the second insulating film preferably has a first film body part disposed on the second electrode and having a first film thickness, and a second film body part covering the piezoelectric film on side surfaces of the piezoelectric element and having a second film thickness greater than the first film thickness.

In the ultrasonic transducer device as described above, the piezoelectric film is preferably layered on the first electrode, and separated from a surface of a corresponding one of the vibrating film portions by the first electrode, the second electrode is preferably layered on the piezoelectric film, and separated from the first electrode by the piezoelectric film, and the second insulating film preferably has a first film body part disposed on the second electrode and having a first film thickness, and a second film body part covering the second electrode, the piezoelectric film, and the first electrode on side surfaces of the piezoelectric element and having a second film thickness greater than the first film thickness.

An ultrasonic transducer device according to another aspect includes a base, a plurality of piezoelectric elements, a conductive body, and an insulating film. The base has a plurality of vibrating film portions arranged in an array pattern, each of the vibrating film portions having a rectangular shape defined by a pair of long sides and a pair of short sides in a plan view as viewed along a thickness direction of the base. The piezoelectric elements are respectively disposed on the vibrating film portions. The conductive body is disposed on the base, and arranged inside and outside of an area corresponding to each of the vibrating film portions in the plan view. The insulating film covers outside of the area corresponding to each of the vibrating film portions and only a portion of each of the long sides of the vibrating film portions in the plan view.

In the ultrasonic transducer device as described above, the insulating film preferably covers each of the short sides of the vibrating film portions in the plan view.

In the ultrasonic transducer device as described above, each of the piezoelectric elements preferably includes a first electrode disposed on the vibrating film portion, a piezoelectric film covering at least a portion of the first electrode, and a second electrode covering at least a portion of the piezoelectric film. The conductive body preferably includes a first conductive body part connected to the first electrode of each of the piezoelectric elements, and a second conductive body part connected to the second electrode of each of the piezoelectric elements. The second insulating film preferably covers a portion of the piezoelectric film that is not covered by the second electrode or the second conductive body part.

In the ultrasonic transducer device as described above, the insulating film is preferably arranged at both sides of the second electrode so as to sandwich the second electrode.

An ultrasonic transducer device according to another aspect includes a base, a plurality of piezoelectric elements, a conductive body, and an insulating film. The base has a plurality of vibrating film portions arranged in an array pattern. The piezoelectric elements are respectively disposed on the vibrating film portions. The conductive body is disposed on the base, and arranged inside and outside of an area corresponding to each of the vibrating film portions in a plan view as viewed along a thickness direction of the base. The insulating film is disposed on the conductive body only at outside of the area corresponding to each of the vibrating film portions in the plan view.

The ultrasonic waves act on the vibrating film. The ultrasonic waves cause ultrasonic vibration of the vibrating film. Current is output from the piezoelectric element according to the ultrasonic vibration of the vibrating film. In this way, the ultrasonic transducer device detects ultrasonic waves. Here, the insulating film protects the conductive body. The insulating film does not affect the vibrating film, so flexibility of the vibrating film is maintained well. Therefore, it is possible to maintain the ultrasonic wave detection sensitivity.

It is possible to use any of the ultrasonic transducer devices incorporated in a probe. The probe can be equipped with the ultrasonic transducer device and a case supporting the ultrasonic transducer device.

The ultrasonic transducer device can be used incorporated in an electronic instrument. The electronic instrument can be equipped with the ultrasonic transducer device, and a processing unit connected to the ultrasonic transducer device, configured to process output signals of the ultrasonic transducer device.

The ultrasonic transducer device can be used incorporated in an ultrasonic image device. The ultrasonic image device can be equipped with the ultrasonic transducer device, a processing unit connected to the ultrasonic transducer device and configured to process output signals of the ultrasonic transducer device and generate an image, and a display device configured to display the image.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Following, embodiments of the present invention will be explained with reference to the attached drawings. The embodiments explained below shall not be construed as unreasonably limiting the subject matter of the present invention described in the claims, and all the elements explained in the embodiments are not necessarily essential to the solving means of the present invention.

(1) Overall Configuration of Ultrasonic Diagnostic Device

FIG. 1schematically shows a configuration of an ultrasonic diagnostic device (ultrasonic image device)11as an example of an electronic instrument according to an embodiment of the present invention. The ultrasonic diagnostic device11is provided with a device terminal12and an ultrasonic probe (probe)13. The device terminal12and the ultrasonic probe13are connected to each other through a cable14. The device terminal12and the ultrasonic probe13exchange electric signals through the cable14. A display panel (display device)15is incorporated in the device terminal12. A screen of the display panel15is exposed on a surface of the device terminal12. As described later, in the device terminal12, an image is generated based on ultrasonic waves detected with the ultrasonic probe13. Imaged detection results are displayed on the screen of the display panel15.

As shown inFIG. 2, the ultrasonic probe13has a case16. An ultrasonic transducer element unit (hereinafter referred to as “element unit”)17is housed in the case16. The ultrasonic transducer element unit17is a specific example of an ultrasonic transducer device, according to an embodiment of the present invention. A surface of the element unit17may be exposed on a surface of the case16. The element unit17outputs ultrasonic waves from the surface thereof, and receives reflected waves of ultrasonic waves. In addition, the ultrasonic probe13can be equipped with a probe head13blinked to be freely attachable and detachable with the probe main unit13a. At this time, the element unit17can be incorporated inside the case16of the probe head13b.

FIG. 3schematically shows a plan view of the element unit17according to the first embodiment. The element unit17is provided with a base21. An element array22is formed on the base21. The element array22is constructed of ultrasonic transducer elements (hereinafter referred to as “element”)23arranged in an array pattern. The array is formed in a matrix having a plurality of rows and a plurality of columns. In addition, a zigzag pattern may be used in the array. In the zigzag pattern, a group of the elements23in an even column may be displaced with respect to a group of the elements23in an odd column by one-half of the row pitch. The number of the elements in one of an odd column and an even column may be smaller than the number of the elements in the other of an odd column and an even column by one.

Each element23is equipped with a vibrating film24(one example of a vibrating film portion). Details of the vibrating film24are described later. InFIG. 3, the outline of the vibrating film24is depicted with a dotted line with a plan view in the direction orthogonal to the film surface of the vibrating film24(plan view in the substrate thickness direction). The inside of the outline correlates to the area interior of the vibrating film24. The outside of the outline correlates to the area exterior of the vibrating film24. A piezoelectric element25is formed on the vibrating film24. As described later, with the piezoelectric element25, a piezoelectric film (not illustrated) is sandwiched between an upper electrode (second electrode)26and a lower electrode (first electrode)27. These are layered in sequence. The element unit17is constituted as one ultrasonic transducer element chip.

A plurality of first conductive bodies28are formed on the surface of the base21. The first conductive bodies28extend parallel to each other in the column direction of the array. One conductive body28is allocated for each element23of one column. One first conductive body28is arranged in common with elements23aligned in the column direction of the array. The first conductive bodies28form the lower electrode27for each of the elements23. The first conductive bodies28form the conductive body connected to the lower electrode27, specifically, the first conductive body part. In this way, the first conductive bodies28are arranged in the vibrating film24area interior and area exterior. For the first conductive body28, it is possible to use a layered film of titanium (Ti), iridium (Ir), platinum (Pt), and titanium (Ti), for example. However, it is also possible to use other conductive materials for the first conductive body28.

A plurality of second conductive bodies31are formed on the surface of the base21. The second conductive bodies31extend parallel to each other in the row direction of the array. One second conductive body31is allocated to each element23of one row. The one second conductive body31is connected in common to the elements23aligned in the row direction of the array. The second conductive bodies31form the upper electrode26for each of the elements23. The second conductive bodies31form the conductive body connected to the upper electrode26, specifically, the second conductive body part. Both ends of the second conductive body31are respectively connected to a pair of extraction wirings32. The extraction wirings32extend parallel to each other in the column direction of the array. Therefore, all of the second conductive bodies31have the same length. In this way, the upper electrodes26are connected in common to the elements23of the entire matrix. In this way, the second conductive bodies31are arranged in the vibrating film24inside area and outside area. The second conductive body31can be formed using iridium (Ir), for example. However, it is also possible to use other conductive materials for the first conductive body28.

Power distribution of the elements23is switched per column. Linear scanning or sector scanning is achieved corresponding to such switching of power distribution. Since the elements23in one column output ultrasonic waves at the same time, the number of the elements23in one column, that is, the number of rows of the array can be determined based on the output level of ultrasonic waves. For example, the number of rows may be set to be around 10 to 15 rows. In the drawing, five rows are illustrated for simplicity. The number of columns of the array can be determined based on the extent of an area to be scanned. For example, the number of columns may be set to be 128 columns or 256 columns. In the drawing, eight columns are illustrated for simplicity. The role of the upper electrode26and the lower electrode27can also be switched. Specifically, while the lower electrode is connected in common to the elements23of the entire matrix, the upper electrode can be connected in common for each column of the array.

The outline of the base21has a first side21aand a second side21bthat are opposed and partitioned by a pair of straight lines in parallel to each other. One line of a first terminal array33ais arranged between the first side21aand the outline of the element array22. One line of a second terminal array33bis arranged between the second side21band the outline of the element array22. For the first terminal array33a, one line can be formed in parallel to the first side21a. For the second terminal array33b, one line can be formed in parallel to the second side21b. The first terminal array33ais constructed of a pair of upper electrode terminals34and a plurality of lower electrode terminals35. Similarly, the second terminal array33bis constructed of a pair of upper electrode terminals36and a plurality of lower electrode terminals37. Upper electrode terminals34and36are respectively connected to both ends of one extraction wiring32. It is sufficient for the extraction wirings32and the upper electrode terminals34and36to be formed plane-symmetrically with respect to a vertical plane that bisects the element array22. Lower electrode terminals35and37are respectively connected to both ends of one second conductive body31. It is sufficient for the second conductive bodies31and the lower electrode terminals35and37to be formed plane-symmetrically with respect to the vertical plane that bisects the element array22. The outline of the base21is formed to be a rectangle. The outline of the base21may be a square or a trapezoid.

A first flexible printed wiring board (hereinafter referred to as “first wiring board”)38is coupled to the base21. The first wiring board38covers the first terminal array33a. Conductive lines, that is, first signal lines39are formed at one end of the first wiring board38corresponding to the upper electrode terminals34and the lower electrode terminals35, respectively. The first signal lines39are respectively opposed to the upper electrode terminals34and the lower electrode terminals35, and respectively bonded thereto. Similarly, a second flexible printed wiring board (hereinafter referred to as “second wiring board”)41covers the base21. The second flex41covers the second terminal array32b. Conductive lines, that is, second signal lines42are formed at one end of the second wiring board41corresponding to the upper electrode terminals36and the lower electrode terminals37, respectively. The second signal lines42are respectively opposed to the upper electrode terminals36and the lower electrode terminals37, and respectively bonded thereto.

An electrode separation film (fourth insulating film)43is arranged in parallel to the second conductive body31on the vibrating film24. The electrode separation film43extends in band form in the lengthwise direction of the second conductive body31. The electrode separation film43has insulation properties and moisture proof properties. The electrode separation film43is formed from a moisture proof insulating material such as alumina (Al2O3), silicon oxide (SiO2) or the like, for example. The electrode separation films43are formed sandwiching each second conductive body31and separated at both sides of the second conductive body31. The second conductive body31intersects the first conductive body28on the vibrating film24, so the electrode separation film43crosses over the first conductive body28on the vibrating film24.

An insulating film44is formed at the vibrating film24area exterior on the base21. The insulating film44extends in band form in the lengthwise direction of the first conductive body28. The insulating film44is arranged in parallel with the first conductive body28only at the vibrating film24area exterior. The insulating film44is formed from an insulating material with moisture proof properties such as alumina or silicon oxide, for example. The material of the insulating film44is sufficient as long as it matches the material of the electrode separation film43. The insulating film44crosses over the second conductive body31. In this way, the insulating film44is formed on the second conductive body31. The insulating film44is continuous with the electrode separation film. The insulating film44is connected to the electrode separation film43sandwiching the second conductive body31and arranged at both sides of the second conductive body31.

As shown inFIG. 4, the base21is equipped with a substrate46and a flexible film47. The flexible film47is formed on the entire surface on the surface of the substrate46. An opening48is formed in each of the elements23on the substrate46. The openings48are arranged in an array pattern on the substrate46. The outline of the area in which the openings48are arranged correlates to the outline of the element array22. A partition wall49divides between two adjacent openings48. The adjacent openings48are partitioned by, the partition wall49. The wall thickness of the partition wall49correlates to the gap of the openings48. The partition wall49defines two wall surfaces on the inside of the plane that expand parallel to each other. The wall thickness correlates to the distance between the two wall surfaces. Specifically, the wall thickness can be defined as the length of the vertical line orthogonal to the wall surface and sandwiched between the wall surfaces.

The flexible film47is constructed of a silicon oxide (SiO2) layer51layered on the surface of the substrate46, and a zirconium oxide (ZrO2) layer52layered on a surface of the silicon oxide layer51. The flexible film47contacts the openings48. In this manner, a part of the flexible film47corresponding to the outline of the opening48forms the vibrating film24. Of the flexible film47, the vibrating film24is the part that is able to do film vibration in the thickness direction of the substrate46since it opposes the opening48. The film thickness of the silicon oxide layer51can be determined based on the resonance frequency.

The first conductive body28, the piezoelectric film53, and the second conductive body31are layered on a surface of the vibrating film24in this order. The piezoelectric film53may be formed of piezoelectric zirconate titanate (PZT), for example. Another piezoelectric material may be used for the piezoelectric film53. The piezoelectric film53covers at least a portion of the lower electrode27and a portion of the vibrating film24. The upper electrode26covers at least a portion of the piezoelectric film53. Here, the piezoelectric film53completely covers the surface of the first conductive body28under the second conductive body31. The function of the piezoelectric film53is to prevent a short circuit between first conductive body28and the second conductive body31.

As shown inFIG. 4, the electrode separation film43covers the side surface of the piezoelectric element25. Specifically, the electrode separation film43is formed on the piezoelectric film53between the first conductive body28and the second conductive body31. In this way, the surface of the piezoelectric film53is covered by the electrode separation film43between the first conductive body28and the second conductive body31. Here, the electrode separation film43stays inside the area of the vibrating film24in the lengthwise direction of the first conductive body28. The electrode separation film43does not affect the edge of the vibrating film24.

A protective film54is layered on the surface of the base21. The protective film54covers the surface of the base21across the entire surface, for example. As a result, the element array22, the first and second terminal arrays33aand33b, and the first and second wiring boards38and41are covered by the protective film54. For the protective film54, for example, a silicone resin film can be used. The protective film54protects the structure of the element array22, the bonding of the first terminal array33aand the first wiring board38, and the bonding of the second terminal array33band the second wiring board41.

A reinforcing plate55is fixed to a reverse surface of the base21. The reverse surface of the base21is overlapped on a surface of the reinforcing plate55. The reinforcing plate55closes the openings48in the reverse surface of the element unit17. The reinforcing plate55may have a rigid base material. For example, the reinforcing plate55may be formed of a silicon base plate. The plate thickness of the base21is set to be around 100 μm, for example, and the plate thickness of the reinforcing plate55is set to be around 100 to 150 μm, for example. The partition walls49are bonded to the reinforcing plate55. The reinforcing plate55is bonded to each partition wall49in at least one bonding area location. For bonding, an adhesive agent can be used.

As shown inFIG. 5, the piezoelectric film53is covered by the first conductive body28. The piezoelectric film53contacts the surface of the vibrating film24in a range expanding from the edge of the first conductive body28to the outside. The piezoelectric film53completely separates the first conductive body29and the second conductive body31from each other. Short circuits between the first conductive body28and the second conductive body31are avoided. In this way, it is possible for the second conductive body31to extend in the array row direction without interruption. The insulating film44covers the second conductive body31. The insulating film44ends at the vibrating film24area exterior. The insulating film44stays at the vibrating film24area exterior and does not enter the area interior.

(2) Circuit Configuration of Ultrasonic Diagnostic Device

As shown inFIG. 6, the ultrasonic diagnostic device11is equipped with an integrated circuit chip58electrically connected to the element unit17. The integrated circuit chip58is equipped with a multiplexer59and a transmitting and receiving circuit61. The multiplexer59has a group of ports59aon the element unit17side, and a group of ports59bon the transmitting and receiving circuit61side. The first signal lines39and the second signal lines42are connected to the group of ports59aon the element unit17side via the wiring62. In this manner, the group of ports59ais connected to the element array22. Here, a prescribed number of signal lines63within the integrated circuit chip55are connected to the group of ports59bon the transmitting and receiving circuit61side. The prescribed number corresponds to a column number of the elements23output at the same time as scanning is conducted. The multiplexer59controls interconnection between the ports on the cable14side and the ports on the element unit17side.

The transmitting and receiving circuit61has a prescribed number of changing switches64. The changing switches64are connected to the corresponding signal lines63, respectively. The transmitting and receiving circuit61has a transmission channel65and a reception channel66for each of the changing switches64. The transmission channel65and the reception channel66are connected to the changing switch64in parallel. The changing switch64selectively connects the transmission channel65or the reception channel66to the multiplexer59. Pulsars67are incorporated in the transmission channel65. The pulsars67output a pulse signal at a frequency corresponding to the resonance frequency of the vibrating film24. An amplifier68, a low-pass filter (LPF)69, and an analog-digital converter (ADC)71are incorporated in the reception channel66. The output signal of each of the elements23is amplified, and converted into a digital signal.

The transmitting and receiving circuit61has a driving/receiving circuit72. The transmission channel65and the reception channel66are connected to the driving/receiving circuit72. The driving/receiving circuit72controls the pulsars67simultaneously depending on the state of scanning. The driving/receiving circuit72receives a digital signal of an output signal depending on the state of scanning. The driving/receiving circuit72is connected to the multiplexer59through a control line73. The multiplexer59conducts control of interconnection based on a control signal supplied from the driving/receiving circuit72.

A processing circuit74is incorporated in the device terminal12. The processing circuit74can be provided with a central processing unit (CPU) and a memory, for example. The entire operation of the ultrasonic diagnostic device11is controlled in accordance with processing of the processing circuit74. The processing circuit74controls the driving/receiving circuit72in accordance with instructions input by a user. The processing circuit74generates an image in accordance with an output signal of the element23. The image is specified by drawing data.

A drawing circuit75is incorporated in the device terminal12. The drawing circuit75is connected to the processing circuit74. The display panel15is connected to the drawing circuit75. The drawing circuit75generates a driving signal in accordance with drawing data generated in the processing circuit74. The driving signal is sent to the display panel15. As a result, an image is displayed on the display panel15.

(3) Operation of Ultrasonic Diagnostic Device

Next, the operation of the ultrasonic diagnostic device11will be explained briefly. The processing circuit74switches between an ultrasonic diagnostic mode and a sensitivity detection mode. In the ultrasonic diagnostic mode, ultrasonic diagnosis can be implemented using the ultrasonic diagnostic device11. In the sensitivity detection mode, it is possible to determine a decrease in the sensitivity of the piezoelectric element part24. When the processing circuit74selects the ultrasonic diagnostic mode, the processing circuit gives the driving/receiving circuit72instructions to transmit and receive ultrasonic waves. The driving/receiving circuit72supplies a control signal to the multiplexer59, and supplies a driving signal to each of the pulsars67. The pulsars67output pulse signals in response to the supply of the driving signal. The multiplexer59connects the port of the group of ports59ato the port of the group of ports59bin response to the instructions of the control signal. The pulse signals are supplied to the elements23per column through the upper electrode terminals34and36and the lower electrode terminals35and37according to the selection of the port. The vibrating film24vibrates in response to the supply of the pulse signals. As a result, desired ultrasonic wave beams are emitted toward a target (for example, the inside of a human body).

After ultrasonic waves are transmitted, the changing switch64is switched. The multiplexer59maintains the connection relation of the ports. The changing switch64establishes a connection between the reception channel66and the signal line63instead of a connection between the transmission channel65and the signal line63. Reflected waves of ultrasonic waves vibrate the vibrating film24. As a result, an output signal is output from the element23. The output signal is converted into a digital signal, and sent to the driving/receiving circuit72.

Transmission and reception of ultrasonic waves are repeated. For this repetition, the multiplexer59changes the connection relation of the ports. As a result, linear scanning or sector scanning is achieved. When scanning is finished, the processing circuit74generates an image based on the digital signals of the output signals. The generated image is displayed on the screen of the display panel15.

The ultrasonic waves act on the vibrating film24. The ultrasonic waves cause ultrasonic vibration of the vibrating film24. Current is output from the piezoelectric element25according to the ultrasonic vibration of the vibrating film24. In this way, each element23detects ultrasonic waves. Here, the insulating film44protects the second conductive body31. The insulating film44does not affect the vibrating film24, so the flexibility of the vibrating film24is maintained well. Therefore, it is possible to maintain the ultrasonic wave detection sensitivity.

The electrode separation film43insulates the first conductive body28and the second conductive body31from each other. Short circuits are prevented between the first conductive body28and the second conductive body31. The electrode separation film43is continuous with the insulating film44, so the insulating film44is bonded to the conductive body31, and increases the bonding strength of the electrode separation film43. In particular, the insulating film44stipulates displacement in the mutually separating direction by the two electrode separation films43which sandwich the second conductive body and are arranged at both sides of the second conductive body31, so for example even if the electrode separation film43is formed on the side wall of the piezoelectric element25, it is possible to reliably increase the bonding strength of the electrode separation film43. In addition, the insulating film44is formed on the surface of the base21, so it is possible to increase the bonding strength of the insulating film44. As a result, the bonding strength of the electrode separation film is increased.

With this embodiment, the electrode separation film43has moisture proof properties. The electrode separation film43is embedded between the first conductive body28and the second conductive body31, so the electrode separation film43has a waterproofing function at the surface of the piezoelectric film53. The electrode separation film43prevents the infiltration of moisture, and inhibits short circuits between the first conductive body28and the second conductive body31.

(4) Element Unit According to Second Embodiment

FIG. 7schematically shows a plan view of the element unit17aof the second embodiment.FIG. 8is a schematic cross section view along line C-C ofFIG. 7. The cross section view along line A-A ofFIG. 7is similar to that shown inFIG. 4, and thus, omitted herein. With this second embodiment, a first insulating film77ais formed in the vibrating film24area exterior on the base21. The first insulating film77aextends in band form in the lengthwise direction of the first conductive body28. The first insulating film77a, similar to the previously described insulating film44, is arranged in parallel with the first conductive body29only in the vibrating film24area exterior. The first insulating film77ais formed for example from a moisture proof insulating material such as alumina or silicon oxide, for example. The material of the first insulating film77ais sufficient as long as it matches the material of the electrode separation film43. The first insulating film77acrosses over the second conductive body31. In this way, the first insulating film77ais formed on the second conductive body31. The first insulating film77ais continuous with the electrode separation film43. The first insulating film77ais connected to the electrode separation film43sandwiching the second conductive body31and arranged at both sides of the second conductive body31.

A second insulating film77bis formed on the inside area of the vibrating film24. The second insulating film77bextends in band form in the lengthwise direction of the first conductive body28. The second insulating film77bextends in parallel to the first insulating film77abetween adjacent electrode separation films43. The second insulating film77bcovers at least a portion of the piezoelectric element25, and is arranged only on the area interior with a break with the vibrating film24area interior. The second insulating film77bis formed from a moisture proof insulating material such as alumina or silicon oxide, for example. The material of the second insulating film77bis sufficient as long as it matches the material of the electrode separation film43. Here, as is clear fromFIG. 8, the second insulating film77bcovers the side surface of the piezoelectric element25. The second insulating film77bis formed so as to cover the piezoelectric film53not covered by the second conductive body31. The second insulating film77bhas a smaller film thickness than the film thickness of the first insulating film77a. At this time, the film thickness of the second insulating film77bis measured in the direction perpendicular to the side surface of the piezoelectric element25. The second insulating film77bis continuous with the electrode separation film43. The second insulating film77bis connected to the electrode separation film43sandwiching the second conductive body31and arranged at both sides of the second conductive body31.

The first insulating film77aand the second insulating film77bprotect the second conductive body31. The first insulating film77adoes not affect the vibrating film24, so the flexibility of the vibrating film24is maintained well. Therefore, it is possible to maintain the ultrasonic wave detection sensitivity. In addition, the second insulating film77bprotects the piezoelectric element25. The second insulating film77bdoes not cross over the edge of the vibrating film24, so it is possible to maintain the vibrating film24vibration operation well. In fact, the second insulating film77bis formed on the side wall of the piezoelectric element25, so the effect on the flexibility of the vibrating film24is suppressed to a minimum. The flexibility of the vibrating film24can be maintained well. Furthermore, the second insulating film77bstipulates that the electrode separation film43arranged sandwiching the second conductive body31be displaced in the direction separating from each other, so the bonding strength of the electrode separation film43is further increased.

As shown inFIG. 9, for formation of the first insulating film77aand the second insulating film77b, an insulating material layer is formed uniformly on the entire surface on the surface of the base21. For formation, it is possible to use sputtering, for example. A resist film79is formed on the insulating material layer. The resist film79is modeled on the shape of the first insulating film77a. Here, for example when ion etching processing is implemented, the insulation material layer is removed in areas other than that of the resist film79. At this time, the insulation material layer remains under the resist film79. In the periphery of the resist film79, removal of the insulation material layer at the wall surface of the piezoelectric element25is delayed compared to on the surface of the base21, the surface of the vibrating film24, and the top surface of the piezoelectric element25. As a result, even if the insulation material layer is completely removed at the surface of the base21and the surface of the vibrating film24and the top surface of the piezoelectric element25, the insulation material layer remains at the side wall of the piezoelectric element25. In this way, the second insulating film77bis formed. Compared to under the resist film79, at the wall surface of the piezoelectric element25, the insulation material layer is exposed by etching, so the film thickness of the second insulating film77bis reduced more than the film thickness of the first insulating film77a.

As shown inFIG. 10, it is also possible to further form a third insulating film81aon the base21. The third insulating film81aconnects the second insulating film77bto the first insulating film77a. The second insulating film77bhas a first film body part81band a second film body part81c. The first film body part81bis arranged on the top surface of the piezoelectric element25. The second film body part81ccovers the second conductive body31formed on the piezoelectric film53at the side wall of the piezoelectric element25. The first film body part81bconnects adjacent second film body parts81cto each other. The third insulating film81aand the second insulating film77bare formed from a moisture proof insulating material such as alumina or silicon oxide, for example. The material of the first insulating film77ais sufficient as long as it matches the material of the electrode separation film (fourth insulating film)43. It is sufficient to have the third insulating film81aand the first film body part81bfilm thickness match. The film thickness of the third insulating film81aand the first film body part81bis smaller than the film thickness of the second film body part81c. The third insulating film81a, the first film body part81band the second film body part81care continuous with the electrode separation film (fourth insulating film)43sandwiching the second conductive body31and arranged at both sides of the second conductive body31.

The third insulating film81aand the first film body part81bare covered on the second conductive body31on the inside area of the vibrating film24. The third insulating film81aand the first film body part81bprotect the second conductive body31. At this time, the third insulating film81ais thinner than the first insulating film77aand the second insulating film77b, so it is possible to maintain the vibrating operation of the vibrating film24well. In fact, the third insulating film81aand the first film body part81bstipulate that the electrode separation film43arranged sandwiching the second conductive body31be displaced in the direction separating from each other, so the bonding strength of the electrode separation film43is further increased.

As described previously, for formation of the first insulating film77aand the second insulating film77b, it is possible to use ion etching processing. At this time, if the insulating material layer remains on the surface of the base21, the surface of the vibrating film24, and the wall surface and the top surface of the piezoelectric element25, it is possible to form the third insulating film81aand the first film body part81b. In the periphery of the resist film79, removal of the insulation material layer at the wall surface of the piezoelectric element25is delayed compared to on the surface of the base21, the surface of the vibrating film24, and the top surface of the piezoelectric element25, so the film thickness of the third insulating film81aand the first film body part81bis reduced more than the film thickness of the second film body part81c.

As shown inFIG. 11, with the piezoelectric element25, it is also possible to layer the lower electrode27, the piezoelectric film53, and the upper electrode26in that sequence. In this case, the piezoelectric film53is separated from the surface of the vibrating film24by the lower electrode27. The upper electrode26is separated from the lower electrode27by the piezoelectric film53. The lower electrode27, the piezoelectric film53, and the upper electrode26are exposed at the side surface of the piezoelectric element25. The second film body part81cof the second insulating film77bcovers the upper electrode26, the piezoelectric film53, and the lower electrode27at the side surface of the piezoelectric element25. The second insulating film77binsulates the upper electrode26and the lower electrode27. The second insulating film77bprevents short circuits between the upper electrode26and the lower electrode27. The first film body parts81bof the second insulating film77bcovers the second conductive body31at the top surface of the piezoelectric element25. The second conductive body31can reliably be protected. With the embodiment shown inFIG. 11, the same as described previously, the first insulating film77aand the second film body part81cof the second insulating film77bcan remain, and the third insulating film81aand the first film body part81bof the second insulating film77bcan be omitted.

While the present embodiment has been explained in detail as above, it will be apparent to those skilled in the art that various changes and modifications can be made herein without substantially departing from the subject matter and the effect of the present invention. Therefore, such changes and modifications are included in the scope of the invention. For example, the terms used in the specification or the drawings at least once together with a different term having a broader or similar meaning can be replaced with the different term in any portion of the specification or the drawings. Also, the configurations and the operations of the ultrasonic diagnostic device11, the ultrasonic probe13, the probe head13b, the element units17and17a, the elements23and the like are not limited to the present embodiment, and various changes and modifications are possible.

GENERAL INTERPRETATION OF TERMS