Patent Application
20140066778
This application claims priority to Japanese Patent Application No. 2012-187465 filed on Aug. 28, 2012. The entire disclosure of Japanese Patent Application No. 2012-187465 is hereby incorporated herein by reference.
1. Technical Field
The present invention relates to an ultrasonic transducer device, and also relates to a probe, an electronic instrument, and an ultrasonic diagnostic device, and the like using the ultrasonic transducer device.
2. Related Art
An ultrasonic transducer device can be provided with one substrate. Openings are formed in the substrate. An ultrasonic transducer element is provided in each opening. An ultrasonic transducer element is provided with a vibrating film. The vibrating film covers the openings from the surface of the substrate. A piezoelectric element is provided on the vibrating film. The vibration of the vibrating film in each ultrasonic transducer element is generated by the function of the piezoelectric element. The ultrasonic wave is generated in response to the vibration of the vibrating film. In this kind of the ultrasonic transducer device, a piezoelectric film of the piezoelectric element can be thinly formed.
As described in Japanese Laid-open Patent Application Publication No. 2009-302445, a polarization is established in the piezoelectric film. When the piezoelectric film is thinly formed, the coercive voltage is relatively low so that an amount of the polarization tends to be reduced due to disturbance such as electromagnetic noise or temperature, and the like. It is concerned that the amount of the polarization is getting to be reduced over time. The reduction of the polarization becomes the deterioration of the sensitivity so that the deterioration of the sensitivity leads to get worse on the measurement accuracy. However, the sensitivity of the piezoelectric element could not be detected without using a device, which is different from the ultrasonic transducer device, for example, a calibrating apparatus.
According to at least one aspect of the present invention, a sensitivity of a piezoelectric element can be detected without using a device, which is different from an ultrasonic transducer device.
(1) One aspect of the present invention relates to an ultrasonic transducer device comprising: a substrate having a plurality of openings; a vibrating film covering the openings; a piezoelectric element being provided in each opening on the vibrating film; an input section inputting a drive signal to a part of piezoelectric elements among the piezoelectric elements; and a detection section detecting vibration of the piezoelectric elements, in which the drive signal is not inputted, among the piezoelectric elements while the drive signal is inputted to the part of the piezoelectric elements among the piezoelectric elements.
A part of the piezoelectric elements is deformed in response to the supply of the drive signal. The deformation of the piezoelectric element leads to the deformation of the corresponded vibrating film. The substrate is deformed in response to the deformation of the vibrating film. The deformation of the substrate leads to the deformation of another vibrating film. The deformation of another vibrating film generates stress in a piezoelectric element, in which the drive signal is not inputted. An electromotive voltage is generated in the piezoelectric element, in which the drive signal is not inputted. By detecting the electromotive voltage, the sensitivity of the piezoelectric element can be detected without using a device, which is different from the ultrasonic transducer device, for example, a calibrating apparatus.
(2) The ultrasonic transducer device can be provided with a control processing section. The control processing section can determine the sensitivity of the piezoelectric elements based on the detection result that the vibration of a piezoelectric element in which the drive signal is not inputted is detected. Because of this, the quality of the sensitivity can be determined.
(3) In the ultrasonic transducer device, the plurality of openings is arranged in a matrix pattern or a line pattern in plan view of a thickness direction of the substrate. The detection section can detect vibration of a piezoelectric element that is located adjacent to the part of piezoelectric elements, in which the drive signal is inputted, among the piezoelectric elements, in which the drive signal is not inputted. The part of the piezoelectric elements, in which the drive signal is inputted, leads to the deformation of the piezoelectric elements, in which the drive signal is not inputted, securely.
(4) The detection section can detect vibration of a piezoelectric element that is located between two piezoelectric elements, in which the drive signal is inputted, among the piezoelectric elements, in which the drive signal is not inputted, and is also located adjacent to the two piezoelectric elements. Because of this, the deformation force is applied to the piezoelectric element, in which the drive signal is not inputted, from the both sides. Therefore, the stress of the piezoelectric element can be increased by the supply of the drive signal at once. The electromotive voltage of the piezoelectric element is increased. As a result, the detection accuracy of the sensitivity can be increased.
(5) When the control processing section determines that the sensitivity of a piezoelectric element, in which the drive signal is not inputted, is less than a predetermined value, a voltage for polarization can be supplied to the piezoelectric element, in which the drive signal is not inputted. A polarization is established in the piezoelectric element prior to use. The amount of the polarization is reduced over time. As a result, the sensitivity of the piezoelectric element is reduced. Therefore, in a case that the sensitivity of the piezoelectric element is reduced less than the predetermined value, when the voltage for polarization is supplied to the piezoelectric element, a sufficient polarization can be established again in the piezoelectric element. The good sensitivity of the piezoelectric element can be maintained.
(6) When the control processing section determines that the sensitivity of a piezoelectric element, in which the drive signal is not inputted, is less than the predetermined value, a notification signal indicating that the sensitivity is less than the predetermined value can be outputted. The sensitivity deterioration of the piezoelectric element can be notified to outside from the control processing section. A user can recognize the sensitivity deterioration of the piezoelectric element based on the notification.
(7) The ultrasonic transducer device can be provided with the control processing section. The control processing section can output a notification signal based on the detection result that the vibration of a piezoelectric element, in which the drive signal is not inputted, was detected. Because of this, the detection result can be notified to the outside from the control processing section. The user can determine the sensitivity deterioration of the piezoelectric element based on this notification.
(8) Another aspect of the present invention relates to an ultrasonic transducer device comprising: a substrate having a first opening, a second opening, and a partition part, which is wedged between the first opening and the second opening; a vibrating film covering the first opening and the second opening; a first piezoelectric element being provided on the vibrating film including a position overlapped with the first opening in plan view as viewed along the thickness direction of the substrate; a second piezoelectric element being provided on the vibrating film including a position overlapped with the second opening in plan view as viewed along the thickness direction of the substrate; an input section inputting a drive signal to the first piezoelectric element; and a detection section detecting vibration of the second piezoelectric element, in which the drive signal is not inputted, while the drive signal is inputted to the first piezoelectric element. The partition part has a shape that the thickness of the thickness direction of the substrate is larger than a minimum value of distance between the first opening and the second opening in plan view as viewed along the thickness direction of the substrate.
The first piezoelectric element is deformed in response to the supply of the drive signal. The deformation of the first piezoelectric element leads to the deformation of the vibrating film overlapped with the first opening. The partition part is deformed in response to the vibrating film. The deformation of the partition part leads to the deformation of the vibrating film overlapped with the second opening. The deformation of the vibrating film overlapped with the second opening generates the stress in the second piezoelectric element. The electromotive voltage is generated in the second piezoelectric element, in which the drive signal is not inputted. By detecting the electromotive voltage, the sensitivity of the second piezoelectric element can be detected without using a device, which is different from the ultrasonic transducer device, for example, calibrating apparatus.
(9) Further, another aspect of the present invention relates to an ultrasonic transducer device comprising: a substrate having a plurality of first openings, which is arranged in a matrix pattern or a line pattern, and a second opening, which is arranged in an outside of an outline of an area where the plurality of first openings are arranged; a vibrating film covering the first openings and the second opening; a first piezoelectric element being provided on the vibrating film in each of the plurality of first openings in plan view as viewed along the thickness direction of the substrate; a second piezoelectric element being provided on the vibrating film including a position overlapped with the second opening in plan view as viewed along the thickness direction of the substrate; an input section inputting a drive signal to the first piezoelectric elements; and a detection section detecting vibration of the second piezoelectric element, in which the drive signal is not inputted, while the drive signal is inputted to the first piezoelectric elements.
The first piezoelectric elements are deformed in response to the supply of the drive signal. The deformation of the first piezoelectric elements leads to the deformation of the vibrating film overlapped with the first openings. The substrate is deformed in response to the deformation of the vibrating film. The deformation of the substrate leads to the deformation of the vibrating film overlapped with the second opening. The deformation of the vibrating film overlapped with the second opening generates stress in the second piezoelectric element. The electromotive voltage is generated in the second piezoelectric element, in which the drive signal is not generated. By detecting the electromotive voltage, the sensitivity of the second piezoelectric element can be detected without using a device, which is different from the ultrasonic transducer device, for example, a calibrating apparatus.
(10) In the ultrasonic transducer device, the first opening and the second opening can be formed in the same shape, and the first piezoelectric element and the second piezoelectric element can be formed in the same structure. Because of this, the characteristics of the second piezoelectric element can be correlated with the characteristics of the first piezoelectric. The characteristics of the second piezoelectric element can be influenced from the characteristics of the first piezoelectric element with high accuracy.
(11) Further, another aspect of the present invention relates to an ultrasonic transducer device comprising: a substrate having a plurality of first openings, which is arranged in a matrix pattern or a line pattern, a second opening, which is arranged in an outside of an outline of a region where the plurality of first openings is arranged, and a third opening, which is arranged in the outside of the outline of the region where the plurality of first openings is arranged, and is also arranged in a position closer to the second opening than the first openings; a vibrating film covering the first openings, the second opening, and third opening; a first piezoelectric element being provided on the vibrating film in each of the plurality of first openings in plan view of a thickness direction of the substrate; a second piezoelectric element being provided on the vibrating film including a position overlapped with the second opening in plan view as viewed along the thickness direction of the substrate; a third piezoelectric element being provided on the vibrating film including a position overlapped with the third opening in plan view as viewed along the thickness direction of the substrate; an input section inputting a drive signal to the third piezoelectric element; and a detection section detecting vibration of the second piezoelectric element, in which the drive signal is not inputted, while the drive signal is inputted to the third piezoelectric element.
The third piezoelectric element is deformed in response to the supply of the drive signal. The deformation of the third piezoelectric element leads to the deformation of the vibrating film of the third opening. The substrate is deformed in response to the deformation of the vibrating film. The deformation of the substrate leads to the deformation of the vibrating film of the second opening. The deformation of the vibrating film of the second opening generates stress in the second piezoelectric element. The electromotive voltage is generated in the second piezoelectric element, in which the drive signal is not inputted. By detecting the electromotive voltage, the sensitivity of the second piezoelectric element can be detected without using a device, which is different from the ultrasonic transducer device, for example, a calibrating apparatus. Generally, the characteristics of the second piezoelectric element are reflected from the characteristics of the first piezoelectric element so that the sensitivity of the first piezoelectric element can be presumed based on the sensitivity of the second piezoelectric element.
(12) The third piezoelectric element can have larger area than the second piezoelectric element in plan view as viewed along the thickness direction of the substrate. Because of this, a greater deformation force can be applied to the second piezoelectric element. As a result, the accuracy of detection for vibration can be improved.
(13) The ultrasonic transducer device can be provided with the control processing section. The control processing section can determine the sensitivity of the first piezoelectric element based on the detection result that the vibration of the second piezoelectric element in which the drive signal is not inputted is detected. Because of this, the quality of the sensitivity can be determined.
(14) When the control processing section determines that the sensitivity of the first piezoelectric element is less than a predetermined value, a voltage for polarization can be supplied to the first piezoelectric element. A polarization is established in the piezoelectric element prior to use. The amount of the polarization is reduced over time. As a result, the sensitivity of the piezoelectric element is reduced. Therefore, in a case that the sensitivity of the piezoelectric element is reduced less than the predetermined value, when the voltage for polarization is supplied to the piezoelectric element, a sufficient polarization can be established again in the piezoelectric element. The good sensitivity of the piezoelectric element can be maintained.
(15) When the control processing section determines that the sensitivity of the first piezoelectric element is less than the predetermined value, a notification signal indicating that the sensitivity is less than the predetermined value can be outputted. The sensitivity deterioration of the piezoelectric element can be notified to outside from the control processing section. A user can recognize the sensitivity deterioration of the piezoelectric element based on the notification.
(16) Any of the ultrasonic transducer devices can be used by being incorporated in a probe. The probe can be provided with an ultrasonic transducer device and a case that supports the ultrasonic transducer device.
(17) The ultrasonic transducer device can be used by being incorporated in an electronic instrument. The electronic instrument can be provided with the ultrasonic transducer device and a processor that is connected to the ultrasonic transducer device and processes an output of the ultrasonic transducer device.
(18) The ultrasonic transducer device can be used by being incorporated in the ultrasonic diagnostic device. The ultrasonic diagnostic device can be provided with the ultrasonic transducer device, a processor that is connected to the ultrasonic transducer device, processes an output of the ultrasonic transducer device, and generates an image, and a display device that displays the image.
(19) Any of the ultrasonic transducer devices can be used by being incorporated in a probe head. The probe head can be provided with the ultrasonic transducer device, and a case that supports the ultrasonic transducer device.
(20) Further, another aspect of the present invention relates to an ultrasonic transducer device comprising: a substrate having a plurality of openings partitioned by a partition part; a vibrating film covering the openings; a piezoelectric element being provided in each opening on the vibrating film; an input section inputting a drive signal to a part of piezoelectric elements among a plurality of piezoelectric elements; and a detection section detecting vibration of the piezoelectric element, in which the drive signal is not inputted, while the drive signal is inputted in the part of piezoelectric elements. The vibration of the vibrating film vibrated by inputting the drive signal to the part of piezoelectric elements deforms the partition part so as to vibrate the piezoelectric elements, in which the drive signal is not inputted.
The part of the piezoelectric elements is deformed in response to the supply of the drive signal. The deformation of the piezoelectric elements leads to the vibration of the corresponded vibrating film. The partition part is deformed in response to the vibration of the vibrating film. The deformation of the partition part leads to the deformation of another vibrating film. The deformation of another vibrating film generates stress in the piezoelectric elements, in which the drive signal is not inputted. The electromotive voltage is generated in the piezoelectric elements, in which the drive signal is not inputted. By detecting the electromotive voltage, the sensitivity of the piezoelectric elements can be detected without using a device, which is different from the ultrasonic transducer device, for example, calibrating apparatus.
Referring now to the attached drawings which form a part of this original disclosure:
Hereinafter, one embodiment of the present invention will be described with reference to the attached drawings. The present embodiment described below shall not be construed as unreasonably limiting the subject matter of the present invention described in the claims, and all the elements described in the present embodiment are not necessarily essential to the solving means of the present invention.
As shown in
A plural number of the first electric conductors 28 are formed on the surface of the substrate base 21. The first electric conductors are reciprocally extended parallel in a direction of rows in the arrangement. In each element 23 of one row, one first electric conductor 28 is allocated. The one first electric conductor 28 is mutually connected to the piezoelectric film 27 of the element 23 parallel in the direction of rows in the arrangement. The first electric conductor 28 forms an upper electrode in each element 23. The both end parts of the first electric conductor 28 are respectively connected to a pair of extraction wirings 29. The extraction wirings 29 are reciprocally extended in parallel in the direction of columns in the arrangement. Therefore, all of the first electric conductors 28 have the same length. Because of this, the upper electrode 25 is mutually connected to all of the elements 23 in the matrix.
A plural number of the second electric conductors 31 are formed on the surface of the substrate base 21. The second electric conductors 31 are reciprocally extended in parallel to the direction of columns in the arrangement. One second electric conductor 31 is allocated in each one line of the element 23. One second electric conductor 31 is mutually provided in the piezoelectric film 27 of the element 23 in parallel to the direction of columns in the arrangement. A power distribution of the elements 23 is switched in each column. A line scan or a sector scan is realized in response to the power distribution switch. The elements 23 in one column simultaneously output an ultrasonic wave so that number in one column, that is, number of lines in the arrangement can be determined in response to an output level of the ultrasonic wave. For example, the number of lines may be set approximately 10 to 15 lines. In the drawing, it is omitted to 5 lines. The row number of the arrangement can be determined in response to a range of scanning. For example, the number of lines may be set 128 lines or 256 lines. In the drawing, it is omitted to 8 lines. Also, a zigzag pattern may be established in the arrangement. In the zigzag pattern, a group of the elements 23 in an even column may be displaced with respect to a group of the elements 23 in 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. In addition, the functions of the upper electrode 25 and the lower electrode 26 may be switched. That is, the lower electrode is mutually connected to the elements 23 of the entire matrix, and on the other hand, the upper electrode may be mutually connected to the elements 23 in each column of the arrangement.
The outline of the substrate base 21 has a first side 21a and a second side 21b that are opposed and partitioned by a pair of straight lines in parallel to each other. One line of a first terminal array 32a is provided between the first side 21a and an outline of an element array 22. One line of a second terminal array 32b is provided between the second side 23b and the outline of the element array 22. The first terminal array 32a can form one line parallel to the first side 21a. The second terminal array 32b can form one line parallel to the second side 21b. The first terminal array 32a is configured by a pair of upper electrode terminals 33 and a plurality of lower electrode terminals 34. In the same manner, the second terminal array 32b is configured by a pair of upper electrode terminals 35 and a plurality of lower electrode terminals 36. The respective upper electrode terminals 33, 35 are connected to both ends of one extraction wiring 29. It is sufficient for the extraction wiring 29 and the upper electrode terminals 33, 35 to be formed plane-symmetrically with respect to a vertical plane that bisects the element array 22. The respective lower electrode terminals 34, 36 are connected to both ends of one second electric conductor 31. It is sufficient for the second electric conductor 31 and the lower electrode terminals 34, 36 to be formed plane-symmetrically with respect to a vertical plane that bisects the element array 22. Here, the outline of the substrate base 21 is formed to be a rectangular. The outline of the substrate base 21 may be a square or trapezoid.
A first flexible printed circuit board (hereafter referred to as “the first circuit board”) 37 is connected to the substrate base 21. The first circuit board 37 is coupled with to the first terminal array 32a. Conductive lines, that is, first signal lines 38 are formed corresponding to the upper electrode terminals 33 and the lower electrode terminals 34, respectively in one end of the first circuit board 37. The first signal lines 38 are respectively opposed to the upper electrode terminals 33 and the lower electrode terminals 34, and respectively bonded thereto. Similarly, the second flexible printed circuit board (hereinafter referred to as “the second circuit board”) 41 is coupled with the substrate base 21. The second circuit board 41 is coupled with the second terminal array 32b. Conductive lines, that is, second signal lines 42 are formed at one end of the second circuit board 41 corresponding to the upper electrode terminals 35 and the lower electrode terminals 36, respectively. The second signal lines 42 are respectively opposed to the upper electrode terminals 35 and the lower electrode terminals 36, and respectively bonded thereto.
As shown in
The flexible film 45 is constructed of a silicon oxide (SiO2) layer 48 layered on the surface of the substrate 44, and a zirconium oxide (ZrO2) layer 49 layered on a surface of the silicon oxide layer 48. The flexible film 45 contacts the openings 46. Because of this, a part of the flexible film 45 with respect to the outline of the openings 46 forms a vibrating film 51. In the flexible film 45, the vibrating film 51 is a part that faces onto the opening 46 so that it can vibrate in the thickness direction of the substrate 44. The film thickness of the silicon oxide layer 48 can be determined based on resonance frequency.
The second electric conductor 31, the piezoelectric film 27, and the first electric conductor 28 are layered on a surface of the vibrating film 51 in this order. As for the second electric conductor 31, for example, a layered film of titanium (Ti), iridium (Ir), platinum (Pt), and titanium (Ti) can be used. The piezoelectric film 27 may be formed of, for example, piezoelectric zirconate titanate (PZT). The first electric conductor 28 can be formed of, for example, iridium (Ir). Another conductive material may be used in the first electric conductor 28 and the second electric conductor 31, and another piezoelectric material may be used in the piezoelectric film 27. Here, the piezoelectric film 27 completely covers the second electric conductor 31 under the first electric conductor. The function of the piezoelectric film 27 prevents short circuit between the first electric conductor 28 and the second electric conductor 31 from occurring.
A protective film 53 is layered on the surface of the substrate base 21. The protective film 51 covers, for example, the entire surface of the substrate base 21. As a result, the protective film 51 covers the element array 22, the first and the second terminal arrays 32a, 32b, the first and the second circuit boards 37, 41. For example, a silicone resin film may be used for the protective film 53. The protective film 53 protects the structure of the element array 22, the bonding of the first terminal array 32a and the first circuit board 37, and the bonding of the second terminal array 32b and the second circuit board 41.
A reinforcing plate 54 is fixed on the back surface of the substrate base 21. The back surface of the substrate base 21 is overlapped on the surface of the reinforcing plate 54. The reinforcing plate 54 closes the openings 46 on the back surface of the element unit 17. The reinforcing plate 54 can be provided with a rigid substrate. The reinforcing plate can be formed of, for example, silicon substrate. The plate thickness of the substrate base 21 is set, for example, approximately 100 μm, and the plate thickness of the reinforcing plate 54 is set, for example, approximately 100 to 150 μm. Here, the partition wall 47 is bonded to the reinforcing plate 54. The reinforcing plate 54 is bonded to the respective partition walls 47 in at least one bonding region. Adhesive can be used for the bonding.
As shown in
The transmitting and receiving circuit 61 is provided with selecting switches 64 of a prescribed number. The selecting switches are respectively connected to corresponded signal lines 63. The transmitting and receiving circuit 61 is provided with a transmission channel 65 and a reception channel 66 in each of the selecting switches 64. The transmission channels 65 and the reception channels 66 are connected in parallel in the selecting switches 64. The selecting switches 64 alternatively connect the transmission channels 65 or the reception channels 66 to the multiplexer 59. Pulsers 69 are provided in the transmission channels 65. The pulsers 67 output a pulse signal at a frequency corresponding to the resonance frequency of the vibrating films 52. Amplifiers 68, low-pass filters (LPF) 69, and analog-digital converters (ADC) 71 are incorporated in the reception channels 66. A detection signal of each of the elements 23 is amplified, and converted into a digital signal.
The transmitting and receiving circuit 61 is provided with a driving/receiving circuit 72. The transmission channels 65 and the reception channels 66 are connected to the driving/receiving circuit 72. The driving/receiving circuit 72 controls the pulsers 67 simultaneously depending on the state of scanning. The driving/receiving circuit 72 receives a digital signal of an output signal depending on the state of scanning. The driving/receiving circuit 72 is connected to the multiplexer 59 through a control line 73. The multiplexer 59 conducts an interconnection control based on a control signal supplied from the driving/receiving circuit 72.
A processing circuit 74 is incorporated in the device terminal 12. The processing circuit 74 can be provided with, for example, a central processing unit (CPU) 74 and a memory. The entire operations of the ultrasonic diagnostic device 11 are controlled in accordance with processing of the processing circuit 74. The processing circuit 74 controls the driving/receiving circuit 72 in accordance with instructions inputted by a user. The processing circuit 74 generates an image in accordance with an output signal of the elements 23. The image is specified by drawing data.
A drawing circuit 75 is incorporated in the device terminal 12. The drawing circuit 75 is connected to the processing circuit 74. The display panel 15 is connected to the drawing circuit 75. The drawing circuit 75 generates a drive signal in accordance with drawing data generated in the processing circuit 74. The drive signal is sent to the display panel 15. As a result, an image is displayed on the display panel 15.
Next, the operations of the ultrasonic diagnostic device 11 will be briefly described. The processing circuit 74 switches an ultrasonic diagnostic mode and a sensitivity detection mode. In the sensitivity detection mode, a deterioration of the sensitivity of the piezoelectric element section 24 can be determined. When the processing circuit 74 selects the ultrasonic diagnostic mode, the processing circuit 74 provides an instruction to the driving/receiving circuit 72 for transmitting and receiving an ultrasonic wave. The driving/receiving circuit 72 supplies a control signal to the multiplexer 59 and supplies a drive signal to each of the pulsers 67. A pulse signal is outputted in response to the supply of the drive signal. The multiplexer 59 connects the ports of the group of ports 59a to the ports of the group of ports 59b in accordance with the instruction of the control signal. A pulse signal is supplied to elements 23 in each column through the upper electrode terminals 33, 35 and the lower electrode terminals 34, 36 in response to the selection of the ports. The vibrating film 53 vibrates in response to the supply of the pulse signal. As a result, an intended ultrasonic beam is generated toward an object (e.g., inside of human body).
After ultrasonic wave was transmitted, the selecting switches 64 are switched. The multiplexer 59 maintains the connection relation of the ports. The selecting switches 64 establish a connection between the reception channels 66 and the signal lines 63 instead of a connection between the transmission channels 65 and the signal lines 63. Reflected waves of the ultrasonic waves vibrate the vibrating film 43. As a result, an output signal is output from the elements 23. The output signal is converted into a digital signal, and sent into the driving/receiving circuit 72.
Transmission and reception of ultrasonic waves are repeated. For repeating transmission and reception of ultrasonic waves, the multiplexer 59 changes the connection relation of the ports. As a result, the line scanning or the sector scanning is realized. When scanning is completed, the processing circuit 74 generates an image based on the digital signal of the output signal. The generated image is displayed on the screen of the display panel 15.
As shown in
The processing circuit 74 provides an instruction for a supply of a drive signal to the target drive element lines 77 in Step S2. The processing circuit 74 supplies a drive signal to two pulsers 67. The pulsers 67 output pulse signals (drive signals) in response to the supply of the drive signal. The pulse signals are supplied to the target drive element lines 77 through the first electric conductor 28 and the second electric conductor 31. Because of this, a voltage is applied to the respective piezoelectric element sections 24 in the target drive element lines 77. At this time, the driving/receiving circuit 72 functions as an input section to input a drive signal to the piezoelectric element sections 24 of a part of the elements 23.
The piezoelectric films 27 are deformed in response to the supply of the drive signal in the target drive element lines 77. The deformation of the piezoelectric films 27 leads to vibration, that is, the deformation of the vibrating films 51. As shown in
The processing circuit 74 provides an instruction to the target detection element line 76 to receive an output signal in Step S3. In this time, the driving/receiving circuit 72 functions as a detection section to detect the vibration of the piezoelectric element section 24 of the target detection element line 76, that is, the piezoelectric elements, in which the drive signal is not inputted, among the piezoelectric elements while the drive signal is inputted to the piezoelectric element sections 24 of the target drive element lines 77, that is, a part of piezoelectric elements among the piezoelectric elements. The processing circuit 74 identifies a detection value of the output signal. The identified detection value is compared with a threshold value, which is preliminary determined in Step S4. The threshold value may be preliminary stored in a memory section as a memory of the processing circuit 74. When the detection value is more than the threshold value, it is determined as a good sensitivity. The sensitivity detection mode is end. When the detection value is less than the threshold value, the processing circuit 74 determines the low amount of polarization of the piezoelectric films 27. The deterioration of the sensitivity of the piezoelectric element section 24, that is, “abnormality” is determined. Because of this, when the “abnormality” is detected, the processing circuit 74 provides an instruction to execute a polarization process in Step S5. When the polarization process is executed, a voltage for polarization is supplied to the respective polarization body films 27. The polarization is realized in response to the application of the voltage for polarization in the piezoelectric films 27.
As described above, in the element unit 17, the polarization is established in the respective piezoelectric films 27 prior to use. The amount of polarization is reduced over time. As a result, the sensitivity of the elements 23 is deteriorated. Therefore, when voltage for polarization is supplied to the piezoelectric films 27 again in the case that the low sensitivity of the elements 23 is detected, a sufficient polarization can be established again in the piezoelectric films 27. The elements 23 can be recovered in the state of good sensitivity.
In the element unit 17, the elements 23 of the entire element array 22 execute the transmission and the reception of the ultrasonic waves for the ultrasonic diagnostic. The respective elements 23 switch between the transmission and the reception of the ultrasonic waves. The elements 23 emit an ultrasonic beam from the vibrating film 51 at the time of transmission. At the time of reception, the vibration of the vibrating film 51 is generated by the ultrasonic wave reflected from the object. The output signal is outputted from the elements 23 in response to the reflected ultrasonic wave. And, three lines of the group of elements 23 in the element array 22 are used for the judgment of the sensitivity. Therefore, a dedicated structure is not required to be added for the judgment of the sensitivity. The judgment of the sensitivity can be easily realized.
In this example, a deformation force is applied to the vibrating film 51 in the one line of the elements 23, which is the detection target for the judgment of the sensitivity, from the two lines of the elements 23 in both sides. Therefore, it can increase the stress of the piezoelectric films 27, which are the detection target, at one time of the supply of the drive signal compare to the case that a deformation force is simply applied from one line of the elements 23 in a single side. As a result, the accuracy of the judgment can be improved. In the element unit 17, the judgment of the sensitivity in each line of the all lines can be executed. In this case, in the lines in both sides of the element array 22, a deformation force is applied only from one line of the elements 23 in a single side to the piezoelectric films 27, which are the detection target. Also, the lines in the both sides of the element array 22 receive the drive voltage only for the judgment of the sensitivity, and it may not be used for the ultrasonic diagnostic mode.
Regarding the determination of the low amount of the polarization, in addition to the comparison between the detection value and the threshold value of Step S4, a change rate of a signal waveform of an output signal may be observed. For example, when a signal level of the start is more than the threshold value, it can be determined as a good sensitivity. When the signal level of the start is less than the threshold value, it can be determined as the low amount of the polarization. The signal level of the start can be identified based on the size of the signal level detected in a predetermined time interval.
Furthermore, instead of the polarization process of Step S5, the processing circuit 74 may generate a notification signal in response to the detection of the “abnormality”. For example, as a notification, an image signal displaying a deterioration of the sensitivity can be included. The image signal can be sent to the drawing circuit 75. The deterioration of the sensitivity can be notified to the user in the screen-display of the display panel 15. Because of this, the user can recognize the sensitivity deterioration of the piezoelectric film 27. In response to the notification, the probe head 13b or the element unit 17 may be replaced, or the polarization process of the piezoelectric film 27 can be executed through an external device.
In the notification signal, in addition to the above described image signal, an image signal indicating a size of an electromotive voltage may be included. The size of the electromotive voltage is shown in the screen-display of the display panel 15 to the user. The user can determine whether or not the amount of the polarization is an appropriate based on the size of the electromotive voltage. For an output of the notification signal, the processing circuit 74 can outputs an integral signal of a drive period that inputs a drive signal to the piezoelectric element section 24 of the target drive element lines 77. Because of this, an integral value of output signals for the drive period can be obtained.
As shown in
As shown in
Next, as shown in
After that, as shown in
A first auxiliary electric conductor 88 is formed on the surface of the substrate base 21. The first auxiliary electric conductor 88 is mutually allocated to the second element 86 and the third elements 87. The first auxiliary electric conductor 88 is mutually connected to the second element 86 and the third elements 87 of the piezoelectric films 27. The first auxiliary electric conductor 88 forms the upper electrode 25 in the respective elements 86, 87. One end of the first auxiliary electric conductor 88 is connected to, for example, the extraction wiring 29. The first auxiliary electric conductor 88 may be formed in the same material as the first electric conductor 28 and the extraction wiring 29.
A second auxiliary electric conductor 89 is formed on the surface of the substrate. The second auxiliary electric conductor 89 is connected to the second element 86 and the piezoelectric films 27. The second auxiliary electric conductor 89 forms the second element 86 and the lower electrode 26. Because of this, in the second element 86, the drive voltage is applied to the piezoelectric films 27 from the first auxiliary electric conductor 88 and the second auxiliary electric conductor 89. The second auxiliary electric conductor 89 may be formed in the same material as the second electric conductors 31.
A third auxiliary electric conductor 91 is formed on the surface of the substrate base 21. The third auxiliary electric conductor 91 is mutually connected to the third elements 87 of the piezoelectric films 27. The third auxiliary electric conductor 91 forms the lower electrodes 26 of the third elements 87. Because of this, in the third elements 87, the drive voltage is applied to the piezoelectric films 27 from the first auxiliary electric conductor 88 and the third auxiliary electric conductor 91. The third auxiliary electric conductor 91 can be formed in the same material as the second electric conductors 31.
A first auxiliary electrode terminal 92 and a second auxiliary electrode terminal 93 are provided in the first terminal array 32a. The first auxiliary electrode terminal 92 is electrically connected to the second auxiliary electric conductor 89. The first auxiliary electrode terminal 92 and the second auxiliary electric conductor 89 may be unified. The second auxiliary electrode terminal 93 is electrically connected to the third auxiliary electric conductor 91. The second auxiliary electrode terminal 93 and the third auxiliary electric conductor 91 may be unified. The first auxiliary electrode terminal 92 and the second auxiliary electrode terminal 93 are respectively connected to the first wiring plate 37 and the first signal lines 38.
As shown in
At this point, the piezoelectric element sections 24 of the third elements 87 are formed in an area larger than the piezoelectric element sections 24 of the second elements 23, 86. Specifically, the piezoelectric element section 24 of the third elements 87 in the direction intersecting a central axis of the outline of the second element 86 has the second width W2 which is larger than the first width W1 of the piezoelectric element section 24 of the second element 86. In addition, the piezoelectric element sections 24 of the third elements 87 expand to the outside of the outline of the third openings 95. That is, the piezoelectric element sections 24 of the third elements 87 cross the third openings 95 and connect on the other side of the substrate 44. A size of the piezoelectric element section 24 is defined in an area wedged between the upper electrode 25 and the lower electrode 26 in the piezoelectric film 27.
As shown in
When the processing circuit 74 selects the ultrasonic diagnostic mode, in the same manner as the above description, the drive signal is supplied to the first elements 23 in the element array 22 through the upper electrode terminals 33, 35 and the lower electrode terminals 34, 36. The line scanning or the sector scanning is realized by the function of the multiplexer 59. An image is displayed on the screen of the display panel 15 in response to the detection signal.
When the processing circuit 74 selects the sensitivity detection mode, the driving/receiving circuit 72 supplies a control signal to the multiplexer 59. In the control signal, the second element 86 and the third elements 87 are identified. The multiplexer 59 connects the group of ports 59a, which connects to the first auxiliary electrode terminals 92 and the second auxiliary electrode terminals 93, to any ports of the group of ports 59b in accordance with the instruction of the control signal. The first auxiliary electrode terminals 92 are connected to the reception channels 66, and the second auxiliary electrode terminals 93 are connected to the transmission channels 65 in response to the selection of the selecting switches 64.
The processing signal 74 instructs the third elements 87 to supply a drive signal. The processing circuit 74 supplies a drive signal to the pulsers 67. The pulsers 67 output a pulse signal (drive signal) in response to the supply of the drive signal. The pulse signal is supplied to the third elements 87 through the first auxiliary electric conductor 88 and the second auxiliary electric conductor 89.
The piezoelectric films 27 are deformed in response to the supply of the drive signal in the third elements 87. The deformation of the vibrating films 51 of the third elements 87 leads to the deformation in the vibrating film 51 of the second element 86. A stress is generated in the piezoelectric film 27 of the second element 86 in response to this deformation. An electromotive voltage is generated in the piezoelectric film 27 in response to the generation of the stress. The electromotive voltage is outputted as an output signal.
The processing circuit 74 instructs the second element 86 to receive an output signal. The output signal is converted to a digital signal and sent to the driving/receiving circuit 72. The processing circuit 74 identifies the detection value of the output signal. The identified detection value is compared with a threshold value that was preliminary set. When the detection value is more than the threshold value, the sensitivity detection mode is end. When the detection value is less than the threshold value, the processing circuit 74 determines the low amount of the polarization of the piezoelectric film 27. Generally, when the low sensitivity of the piezoelectric element section 24 in the second element 86, that is, “abnormality” is determined, in the same manner as the above description, the processing circuit 74 may instruct an execution of the polarization treatment or may generate a notification signal.
Here, the second element 86 has the same structure as the first elements 23. The second opening 94 has the same shape as the first openings. The vibrating films 51 have the same shape and the same film thickness. The piezoelectric element sections 24 have the same structure. In this way, the characteristics of the second element 86 can be easily related to the characteristics of the first elements 23. The characteristics of the second element 86 can be reflected from the characteristics of the first elements 23 with high accuracy. The variability of the characteristics in the respective elements in the element array 22 is small so that when the characteristics are identified in one second element 86, the characteristics of all of the first elements 23 can be presumed.
In the piezoelectric element set 85, the deformation force is applied from the both sides of the third elements 87 to the vibrating film 51 of the second element 86, which is a detection target. Therefore, the stress of the piezoelectric film 27 as a detection target can be increased by the supply of the drive signal at once compare to the case that the deformation force is simply applied from one side. The electromotive voltage of the piezoelectric film 27 is increased. As a result, the accuracy of the judgment can be improved. In addition, the vibrating films 51 of the third elements 87 can increase the deformation of the piezoelectric films 27. The accuracy of the judgment can be more improved. However, as long as the deformation force is sufficiently applied to the piezoelectric film 27 of the second element 86 from the piezoelectric of the third elements 87, the vibrating films 51 in the third elements 87 can be omitted.
In the piezoelectric element set 85, the piezoelectric element sections 24 of the third elements 87 are formed larger than the piezoelectric element section 24 of the second element 86. Thus, larger deformation force is applied to the second element 86. As a result, the accuracy of the judgment can be improved. The piezoelectric element set 85 is arranged in the outside of the outline of the element array 22 so that the expansion of the third elements 87 does not affect to the first elements 23 in the element array 22.
In addition, the piezoelectric element sections 24 of the third elements 87 expand to the outside of the outline of the third openings 95. The deformation of the third elements 87 can be directly transmitted to the substrate 44 of the surrounding of the second opening 94, that is, the partition wall 47. Therefore, the deformation of the third elements 87 can be efficiently transmitted to the second element 86 compare to the case that the deformation of the third elements 87 is transmitted to the substrate 44 of the surrounding of the second opening 94 through the vibrating film 51. As a result, the stress of the second element 86 can be increased. The accuracy of the judgment can be improved.
When the processing circuit 74 selects the sensitivity detection mode, the driving/receiving circuit 72 supplies a control signal to the multiplexer 59. In the control signal, the second element 86 and one line of the group of the first elements 23, which is the closest to the second element 86, are identified (hereinafter referred to as “target drive element line”). The multiplexer 59 respectively connects the ports of the group of ports 59a, which connects to the target drive element line and the second auxiliary electrode terminal 93, to any ports of the group f ports 59b in accordance with the instruction of the control signal. The first auxiliary electrode terminals 92 are connected to the reception channels 66 and the second auxiliary electrode terminals 93 are connected to the transmission channels 65 in response to the selection of the selecting switches 64.
By the way, the present embodiments were described above in detail, but it will be apparent to those skilled in the art that various modifications can be made in a scope not substantially deviating 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 device 11, 11a, the ultrasonic probe 13, the prove head 13b, the element units 17, 17a, the elements 23, 86, 87, the integrated circuit 58, 58a, and the like are not limited to the present embodiment, and various modifications are possible.
In understanding the scope of the present invention, the term “comprising” and its derivatives, as used herein, are intended to be open ended terms that specify the presence of the stated features, elements, components, groups, integers, and/or steps, but do not exclude the presence of other unstated features, elements, components, groups, integers and/or steps. The foregoing also applies to words having similar meanings such as the terms, “including”, “having” and their derivatives. Also, the terms “part,” “section,” “portion,” “member” or “element” when used in the singular can have the dual meaning of a single part or a plurality of parts. Finally, terms of degree such as “substantially”, “about” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. For example, these terms can be construed as including a deviation of at least ±5% of the modified term if this deviation would not negate the meaning of the word it modifies.
While only selected embodiments have been chosen to illustrate the present invention, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made herein without departing from the scope of the invention as defined in the appended claims. Furthermore, the foregoing descriptions of the embodiments according to the present invention are provided for illustration only, and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-187465 | Aug 2012 | JP | national |
