Ultrasonic probe

Abstract

The invention provides an ultrasonic probe which can easily and reliably perform grounding wiring. The vibrator array (16) has two dummy vibrators (22) adjacent to the active portion (16A). Each of the dummy vibrators (22) has a conductive portion comprising a dummy piezoelectric layer and a dummy reflective layer. The ground wire in the wiring sheet (26) is electrically connected to the ground film via the two conductive portions. Two second slits (24) are provided between the two dummy oscillators (22) and the active portion (16A). The wiring sheet (26) has a lower wiring pattern, an upper wiring pattern, and a through-hole group.

Description

Technical Field

[0001] The present invention relates to an ultrasonic probe, and more particularly to a structure of an ultrasonic probe. Background Art

[0002] An ultrasonic probe is used in ultrasonic examinations. Known ultrasonic probes include those that are brought into contact with the body surface of a subject, those that are inserted into the body of a subject, and those that are assembled into an endoscope. An ultrasonic probe assembled into an endoscope may also be referred to as an ultrasonic sensor.

[0003] The ultrasonic probe has an assembly disposed within a housing. The assembly typically includes a backing, a wiring sheet, an oscillator array, a ground film, and an acoustic lens, etc. The oscillator array is composed of a plurality of oscillators arranged in the long side direction. The long side direction is the oscillator arrangement direction, which is also referred to as the major axis direction. The direction orthogonal to the long side direction is referred to as the short side direction or the minor axis direction. The wiring sheet is usually composed of a flexible printed circuit (FPC) substrate. The ground film is composed of copper foil or the like.

[0004] Each of the plurality of oscillators (transducers) constituting the oscillator array has a piezoelectric layer. Each piezoelectric layer is composed of a piezoelectric material as a mechanoelectric conversion material and has a signal electrode and a ground electrode. The plurality of signal electrodes of the plurality of piezoelectric layers are connected to a plurality of signal lines within the wiring sheet. The plurality of ground electrodes of the plurality of piezoelectric layers are connected to one or more ground lines within the wiring sheet via the ground film.

[0005] In Patent Document 1 Figure 2 there is disclosed an ultrasonic probe having an oscillator array and a wiring sheet. The wiring sheet has a first portion disposed on the lower side of the oscillator array and a pair of second portions pulled out from both sides in the long side direction of the first portion. In Patent Document 1 Figure 9 there is shown a structure for connecting signal lines and ground lines to the piezoelectric layer.

[0006] In Patent Document 2 Figure 3 and Figure 7 there are also disclosed an oscillator array and a wiring sheet. A virtual oscillator for ground wiring is not disclosed in Patent Document 1 and Patent Document 2.

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2013 - 150681

[0008] Patent Document 2: International Publication No. 2020 / 079855

[0009] In the assembly disposed within the ultrasonic probe, if the two end portions of the ground film are connected to the ground line of the wiring sheet by soldering, problems such as an increase in the operation burden, the need to secure a soldering area on the wiring sheet, and thermal damage to the piezoelectric layer array will occur. Summary of the Invention

[0010] An object of the present invention is to enable easy and reliable ground wiring in an ultrasonic probe. Alternatively, an object of the present invention is to provide an oscillator array having good electrical characteristics and good physical characteristics.

[0011] The ultrasonic probe according to the present invention is characterized by comprising:

[0012] An oscillator array having a plurality of actual oscillators each having a plurality of actual piezoelectric layers and a virtual oscillator having a virtual piezoelectric layer;

[0013] A ground film provided on the upper side of the plurality of actual piezoelectric layers and the virtual piezoelectric layer and electrically connected to a plurality of ground electrodes of the plurality of actual piezoelectric layers and the upper surface electrode of the virtual piezoelectric layer; and

[0014] A wiring piece provided on the lower side of the oscillator array and having a plurality of signal lines electrically connected to a plurality of signal electrodes of the plurality of actual piezoelectric layers and a ground wire electrically connected to the ground film,

[0015] The virtual oscillator has a conductive portion including the virtual piezoelectric layer, and the conductive portion is provided between the ground film and the wiring piece,

[0016] The ground film and the ground wire are electrically connected via the conductive portion.

[0017] Advantages of the Invention

[0018] According to the present invention, easy and reliable ground wiring can be achieved in an ultrasonic probe. Alternatively, according to the present invention, an oscillator array having good electrical characteristics and good physical characteristics can be provided. Description of the Drawings

[0019] Figure 1 is a cross-sectional view showing an ultrasonic probe according to an embodiment.

[0020] Figure 2 is a cross-sectional view showing an assembly.

[0021] Figure 3 is a plan view showing a wiring piece.

[0022] Figure 4 is a view showing an upper-side wiring pattern and a lower-side wiring pattern.

[0023] Figure 5 is a perspective view showing a part of an intermediate assembly.

[0024] Figure 6 is a developed view showing an example of a ground film.

[0025] Figure 7 This is a diagram showing the first example of a wiring pattern.

[0026] Figure 8 This is a diagram showing the second example of a wiring pattern.

[0027] Figure 9 This is a diagram showing the third example of a wiring pattern.

[0028] Figure 10 This is a flowchart showing the manufacturing method of the ultrasonic probe according to the embodiment.

[0029] Symbol Explanation

[0030] 10 - Front end portion, 12 - Ultrasonic probe, 14 - Backing, 15 - Assembly, 16 - Oscillator array, 16A - Effective part, 18 - Grounding film, 19 - Acoustic lens, 20 - Actual oscillator, 22 - Virtual oscillator, 24 - Second slit, 26 - Wiring piece, 42 - First slit, 46 - Piezoelectric layer (actual piezoelectric layer), 48 - Reflective layer (actual reflective layer), 52 - Matching layer (actual matching layer), 54 - Virtual piezoelectric layer, 56 - Virtual reflective layer, 60 - Virtual matching layer, 70 - Lower - side wiring pattern, 72 - Upper - side wiring pattern. Detailed Embodiment

[0031] Hereinafter, the embodiment will be described with reference to the drawings.

[0032] (1) Outline of the Embodiment

[0033] The ultrasonic probe according to the embodiment includes an oscillator array, a grounding film, and a wiring piece. The oscillator array includes a plurality of actual oscillators of a plurality of actual piezoelectric layers and virtual oscillators having virtual piezoelectric layers. The grounding film is disposed above the plurality of actual piezoelectric layers and the virtual piezoelectric layers. More specifically, the grounding film is electrically connected to a plurality of grounding electrodes of the plurality of actual piezoelectric layers and the upper - surface electrode of the virtual piezoelectric layer. The wiring piece is disposed below the oscillator array. More specifically, the wiring piece includes a plurality of signal lines electrically connected to a plurality of signal electrodes of the plurality of actual piezoelectric layers and a ground line electrically connected to the grounding film. The virtual oscillator has a conductive portion disposed between the grounding film and the wiring piece. The conductive portion has a virtual piezoelectric layer. The grounding film and the ground line are electrically connected via the conductive portion.

[0034] According to the above structure, the grounding film and the ground line are electrically connected via the conductive portion in the virtual oscillator, so there is no need to weld the grounding film to the wiring piece. Therefore, the grounding wiring can be easily and reliably performed. And the acoustic characteristics of the oscillator array can be maintained or improved. In the present specification, the expression of electrical connection may include direct connection and indirect connection.

[0035] In an embodiment, the virtual piezoelectric layer has an upper surface electrode, a lower surface electrode, and side electrodes connected to the upper surface electrode and the lower surface electrode. The side electrodes function as short-circuit electrodes. Two virtual oscillators may be provided on both sides of the effective portion including a plurality of actual oscillators. Three or more virtual oscillators may also be provided. The side electrodes are electrodes formed on a vertical plane (a plane intersecting the oscillator arrangement direction) in the piezoelectric layer.

[0036] In an embodiment, the plurality of actual oscillators have a plurality of actual reflective layers having conductivity provided on the lower sides of the plurality of actual piezoelectric layers. The conductive portion has a virtual reflective layer having conductivity provided on the lower side of the virtual oscillator. Each actual reflective layer has a function of reflecting ultrasonic waves emitted from each piezoelectric layer downward. In the virtual oscillator, both the virtual piezoelectric layer and the virtual reflective layer function as electrical connection components.

[0037] In an embodiment, the oscillator array has a long side direction. The width of the virtual oscillator in the long side direction is greater than the width of each actual oscillator in the long side direction. According to this structure, the resistance of the ground path can be reduced. Moreover, the oscillator array can be physically strengthened. Generally, at both ends of the oscillator array in the long side direction, oscillator breakage (specifically, oscillator collapse) is likely to occur. According to the above structure, such a problem is not likely to occur.

[0038] In an embodiment, the oscillator array has an effective portion and a second slit. The effective portion is composed of a plurality of actual oscillators and a plurality of first slits for separating each actual oscillator from other actual oscillators. The second slit is provided between the effective portion and the virtual oscillator. The width of the second slit in the long side direction is greater than the width of each first slit in the long side direction.

[0039] According to the above structure, the insulation between the actual oscillator existing at the end of the effective portion and its adjacent virtual oscillator can be improved. For example, when a re-polarization process is performed on the effective portion, short-circuiting is not likely to occur between the actual oscillator existing at the end and its adjacent virtual oscillator. When the oscillator array has a curved shape, the width of the second slit in the long side direction is the width of the bottom in the second slit. Similarly, the width of each first slit in the long side direction is the width of the bottom in each first slit.

[0040] In an embodiment, the ground film includes: a film main body having a plurality of strips; and a pair of film end portions connected to the plurality of strips. The plurality of strips are composed of a plurality of strips electrically joined to the plurality of ground electrodes and a strip electrically joined to the upper surface electrode of the virtual piezoelectric layer. Each strip is an elongated sheet-like or strip-like portion.

[0041] In an embodiment, the oscillator array has a long side direction and a short side direction intersecting the long side direction. The wiring sheet has an upper wiring pattern, a lower wiring pattern, and a via hole group. The upper wiring pattern has a plurality of upper signal lines electrically connected to the signal electrodes of a plurality of actual oscillators and arranged in the long side direction, and an upper ground line electrically connected to the lower surface electrode of the virtual oscillator. The lower wiring pattern has a plurality of lower signal lines and a lower ground line arranged in the short side direction. The via hole group has a plurality of signal vias connecting the plurality of upper signal lines and the plurality of lower signal lines, and a ground via electrically connecting the upper ground line and the lower ground line.

[0042] In an embodiment, the wiring sheet has a sheet body, a first stretched portion, and a second stretched portion. The sheet body is disposed on the lower side of the oscillator array. The sheet body has one end and the other end separated in the long side direction. The first stretched portion is a portion pulled out from one end of the sheet body. The second stretched portion is a portion pulled out from the other end of the sheet body. The plurality of actual oscillators are n actual oscillators from the first actual oscillator to the nth actual oscillator arranged in the long side direction in sequential order. The plurality of lower signal lines have a first lower signal line group and a second lower signal line group. The first lower signal line group is electrically connected to the actual oscillators with odd numbers among the n actual oscillators, and is disposed over the sheet body and the first stretched portion. The second lower signal line group is electrically connected to the actual oscillators with even numbers among the n actual oscillators, and is disposed over the sheet body and the second stretched portion.

[0043] In an embodiment, the plurality of signal vias have a first signal via column connected to the first lower signal line group and a second signal via column connected to the second lower signal line group. The first signal via column is aligned along the diagonal direction of the sheet body. The second signal via column is displaced from the first signal via column and is aligned along the diagonal direction.

[0044] According to the above structure, a certain distance between signal vias can be ensured, and the inclination angle of each signal via column with respect to the long side direction can be reduced. Therefore, the width of the wiring sheet in the short side direction can be reduced.

[0045] The ultrasonic probe according to the embodiment includes a first assembly (intermediate assembly), a backing, and a housing. The first assembly is composed of an oscillator array, a ground film, and a wiring sheet. The backing is provided on the lower side of the first assembly. The backing has a first end portion and a second end portion separated in the long side direction. The housing houses a second assembly composed of the first assembly and the backing. The wiring sheet has a sheet body, a first stretching portion, and a second stretching portion. The sheet body is a portion provided on the lower side of the oscillator array. The sheet body has one end and the other end separated in the long side direction. The first stretching portion is a portion pulled out from one end of the sheet body. The second stretching portion is a portion pulled out from the other end of the sheet body. After the first stretching portion enters the lower space through the space adjacent to the first end portion, it turns in a U shape in the lower space. The second stretching portion enters the lower space through the space adjacent to the second end portion. The end portions of the first stretching portion and the second stretching portion overlap on the lower side of the backing.

[0046] According to the above structure, since the two end portions of the two stretching portions overlap, even if the lower space is a small space, the lower space can be utilized to connect a plurality of cables (for example, more than 100 cables) to the wiring sheet.

[0047] (2)Details of the embodiment

[0048] In Figure 1 the front end portion 10 of the endoscope is shown. The endoscope has an imaging element, an illumination element, a water supply and air supply hole, a channel opening, etc., but their illustrations are omitted. The ultrasonic probe 12 according to the embodiment is assembled in the front end portion 10. The ultrasonic probe 12 according to the embodiment may also be assembled in other endoscopes. The ultrasonic probe 12 may also be used alone. The ground wiring technology and the like described below may also be applied to other ultrasonic probes (for example, an ultrasonic probe that abuts against the body surface).

[0049] In Figure 1 a direction is the central axis direction of the ultrasonic probe. The b direction is the long side direction, which is the oscillator arrangement direction. The b direction intersects the a direction. The direction intersecting the a direction and the b direction is the short side direction. The a direction is inclined with respect to the endoscope central axis (the central axis of the front end portion 10). From the ultrasonic probe 12, the a direction can be said to be the up and down direction. In this case, the up direction is the ultrasonic wave emission direction.

[0050] The ultrasonic probe 12 is a convex ultrasonic probe. The ultrasonic probe 12 includes an assembly (second assembly, final assembly) 15, and the assembly 15 is composed of an intermediate assembly (first assembly), a backing 14, and an acoustic lens 19. The intermediate assembly is composed of an oscillator array 16, a ground film 18, and a wiring sheet 26.

[0051] The oscillator array 16 is composed of a plurality of oscillators arranged in the long side direction. InFigure 1 In [description], the illustration of the middle part of the oscillator array 16 is omitted. Specifically, the oscillator array 16 has an effective part 16A for transmitting and receiving ultrasonic waves. The effective part 16A has a plurality of actual oscillators 20 arranged in the long side direction. And the effective part 16A has a plurality of first slits for separating each actual oscillator 20 from other actual oscillators. A plurality of actual oscillators 20 and a plurality of first slits are alternately arranged along the long side direction.

[0052] The oscillator array 16 has two virtual oscillators 22 provided on both sides in the long side direction of the effective part 16A. Each virtual oscillator 22 does not perform an acoustic function but performs an electrical function. As will be described in detail later, each virtual oscillator 22 is a conductive component for ground wiring. The oscillator array 16 has two second slits (gaps) 24 provided between the two virtual oscillators 22 and the effective part 16A.

[0053] The plurality of oscillators in the oscillator array 16 have a plurality of piezoelectric layers. A ground film 18 is provided on the upper side of the plurality of piezoelectric layers (however, the ground film 18 is not explicitly shown in [description]). The ground film 18 is made of, for example, copper foil. In the embodiment, the upper surface electrodes (ground electrodes) of the plurality of piezoelectric layers of the plurality of oscillators are joined to the ground film 18. Figure 1 In [description], the ground film 18 is not explicitly shown.

[0054] An acoustic lens 19 is provided on the upper side of the oscillator array 16. The acoustic lens 19 has a function of focusing ultrasonic waves in the short side direction. A ground film 18 can be provided between the oscillator array 16 and the acoustic lens 19. In this case, a conductive matching layer is provided as the matching layer of each oscillator.

[0055] A wiring sheet 26 is provided on the lower side of the oscillator array 16. The wiring sheet 26 is made of a flexible printed circuit (FPC) substrate. In the embodiment, the wiring sheet 26 is made of a multi-layer FPC substrate. The wiring sheet 26 has a sheet body 28 provided on the lower side of the oscillator array 16, a stretching part 30 pulled out from one end in the long side direction of the sheet body 28, and a stretching part 32 pulled out from the other end in the long side direction of the sheet body 28.

[0056] The sheet body 28 is joined to the upper surface of the backing 14. Its upper surface is a curved convex surface. The backing 14 is a component for attenuating ultrasonic waves radiated to the lower side of the oscillator array 16. The backing 14 has a first end portion 14A and a second end portion 14B separated in the long side direction. The first end portion 14A has a first side surface intersecting the long side direction. The second end portion 14B has a second side surface intersecting the long side direction. The backing 14 also has a third side surface and a fourth side surface intersecting the short side direction, and has a lower surface. Its lower surface faces the lower side space 33.

[0057] After the stretching part 30 enters the lower space 33 through the space adjacent to the first end part 14A, it turns in a U shape within the lower space 33. The stretching part 30 has a first part 30a, a second part 30b, and a third part 30c. The first part 30a is the part that contacts the first side surface of the first end part 14A. The second part 30b is the part that contacts the lower surface of the backing 14. The third part 30c is the part that is parallel to the second part 30b below the second part 30b. There is a bending part between the sheet body 28 and the first part 30a, a bending part between the first part 30a and the second part 30b, and a turning part between the second part 30b and the third part 30c.

[0058] The stretching part 32 enters the lower space 33 through the space adjacent to the second end part 14B. The stretching part 32 has a first part 32a and a second part 32b. The first part 32a is the part that contacts the second side surface of the second end part 14B. The second part 32b is the part that enters below the third part 30c. There is a bending part between the sheet body 28 and the first part 32a, and a bending part between the first part 32a and the second part 32b.

[0059] A first connection area is provided on the upward-facing surface at the end of the third part 30c. A plurality of cables forming the cable group 34 are connected to the first connection area. A second connection area is provided on the downward-facing surface at the end of the second part 32b. A plurality of cables forming the cable group 36 are connected to the second connection area. Each of the cable groups 34, 36 is composed of dozens or hundreds of cables. In Figure 1 the cable groups 34, 36 are schematically shown. Within the lower space 33, the end of the third part 30c overlaps with the end of the second part 32b. The lengths of the stretching part 30 and the stretching part 32 are set to produce this overlap.

[0060] An intermediate assembly is formed by the wiring sheet 26, the oscillator array 16, and the ground film 18. An assembly (the second assembly, the final assembly) 15 is formed by the intermediate assembly, the backing 14, and the acoustic lens 19. The assembly 15 is disposed within the housing of the front end part 10. In the state where the assembly 15 is disposed within the housing, a lower space 33 is generated below the backing 14. Two end parts of the wiring sheet 26 are accommodated within this lower space 33.

[0061] In Figure 2 a vertical cross-section of the intermediate assembly 44 is schematically shown. The intermediate assembly 44 is composed of the wiring sheet 26, the oscillator array 16, and the ground film 18. In Figure 2 the intermediate assembly 44 is in an unfolded state, that is, in a state before bending. Additionally, the horizontal direction, i.e., the y direction, corresponds to the long side direction, and the vertical direction, i.e., the z direction, corresponds to the central axis direction.

[0062] The oscillator array 16 has an effective portion 16A, two dummy oscillators 22, and two second slits 24. The effective portion 16A has a plurality of actual oscillators 20 and a plurality of first slits 42. Each actual oscillator 20 has a piezoelectric layer (actual piezoelectric layer) 46, a reflective layer (actual reflective layer) 48, and a matching layer (actual matching layer) 52. The matching layer 52 may be composed of a plurality of layers.

[0063] Each piezoelectric layer 46 has a signal electrode as a lower surface electrode and a ground electrode as an upper surface electrode. A strip (elongated sheet) 50 in the ground film is joined to the ground electrode. In other words, the ground electrode and the matching layer 52 sandwich the strip 50.

[0064] The reflective layer 48 has a function of reflecting ultrasonic waves radiated downward from the piezoelectric layer 46. The acoustic impedance of the reflective layer 48 is greater than the acoustic impedance of the piezoelectric layer 46. The piezoelectric layer 46 and the reflective layer 48 are integrated to form a resonator.

[0065] Each dummy oscillator 22 has a dummy piezoelectric layer 54, a dummy reflective layer 56, and a dummy matching layer 60. The dummy piezoelectric layer 54 has conductivity or a short-circuit function. Specifically, the dummy piezoelectric layer 54 has a lower surface electrode 62, an upper surface electrode 64, and a side electrode 66. Through the side electrode 66, the lower surface electrode 62 is electrically connected to the upper surface electrode 64, that is, a short circuit is formed between the lower surface electrode 62 and the upper surface electrode 64. A strip 58 is joined to the upper surface electrode 64.

[0066] The plurality of piezoelectric layers 46 and the two dummy piezoelectric layers 54 are each composed of the same piezoelectric material (for example, PZT). The plurality of reflective layers 48 and the two dummy reflective layers 56 are each composed of the same conductive material. The plurality of matching layers 52 and the two dummy matching layers 60 are each composed of the same material. Each dummy oscillator 22 does not function acoustically but functions electrically. That is, it functions as an electrical component for ground wiring.

[0067] The wiring sheet 26 has an insulating layer 68, a lower side wiring pattern (lower side wiring layer) 70, and an upper side wiring pattern (upper side wiring layer) 72. The sheet body 28 of the wiring sheet 26 has a through-hole group 74. The through-hole group 74 includes a plurality of signal through-holes 76 and a plurality of ground through-holes 78. Each through-hole is a component for electrically connecting the lower side electrode pattern and the upper side electrode pattern, specifically, a through-hole having conductivity.

[0068] The lower side wiring pattern 70 includes a plurality of lines arranged in the short side direction, specifically, a plurality of lower side signal lines and a plurality of lower side ground lines. The upper side wiring pattern 72 includes a plurality of lines arranged in the long side direction, specifically, a plurality of upper side signal lines and a plurality of upper side ground lines. Each line corresponds to an electrode or an electrical path.

[0069] A plurality of lower side signal lines are connected to a plurality of upper side signal lines via a plurality of signal vias 76. The plurality of upper side signal lines 94 are connected to signal electrodes of a plurality of piezoelectric layers 46 via a plurality of reflection layers 48.

[0070] In each virtual oscillator 22, the virtual piezoelectric layer 54 has conductivity, and the virtual reflection layer 56 below it also has conductivity. Therefore, in each virtual oscillator 22, the virtual piezoelectric layer 54 and the virtual reflection layer 56 constitute a conductive part. For example, the lower side ground line is connected to the upper side ground line 96 via a ground via 78. The upper side ground line 96 is connected to the ground film 18 via the conductive part.

[0071] The lower side ground line and the upper side ground line can be connected through a plurality of ground vias. Also, a structure for connecting the ground line and the ground film may be provided on the effective part 16A.

[0072] For example, in each piezoelectric layer 46, the length in the short side direction is, for example, 2 mm or 3 mm, the width 82 in the y direction is, for example, 100 μm, and the thickness in the z direction is, for example, 100 μm. In each virtual piezoelectric layer 54, the length in the short side direction is, for example, 2 mm or 3 mm, the width 84 in the y direction is, for example, 150 μm, and the thickness in the z direction is, for example, 100 μm. The numerical values given in this specification of the present application are merely illustrative.

[0073] In the embodiment, the width 84 is greater than the width 82. Thereby, the resistance of the ground path is reduced. Also, the structure at both ends of the oscillator array 16 is physically strengthened. Each virtual oscillator 22 is less likely to collapse. Since two virtual oscillators 22 are provided on both sides in the long side direction of the effective part 16A, the effective part 16A is physically protected.

[0074] The width 86 in the y direction of each first slit 42 is, for example, 50 μm. The width 88 in the y direction of each second slit 24 is, for example, 100 μm. The width 88 is greater than the width 86. Thereby, an electrical short circuit between the actual oscillators at both ends in the effective part 16A and the two virtual oscillators 22 adjacent to the actual oscillators at both ends can be effectively prevented. For example, in the re-poling process of the effective part 16A, a high voltage is applied to the effective part 16A. At this time, a short circuit or poor polarization can be prevented.

[0075] In each piezoelectric layer 46, the lower surface electrode (signal electrode) and the upper surface electrode (ground electrode) are formed by gold plating or the like. These thicknesses are, for example, 0.3 μm. In each virtual piezoelectric layer 54, the lower surface electrode 62, the upper surface electrode 64, and the side surface electrode 66 are formed by gold plating or the like. These thicknesses are, for example, 0.3 μm. The ground film 18 includes, for example, a copper foil with a thickness of 5 μm. Gold plating is also performed on the surface of the ground film 18. The thickness of the gold plating layer is, for example, 0.3 μm.

[0076] In the manufacturing process of the ultrasonic probe, as described later, a reflective material plate, a piezoelectric material plate, and a matching material plate are stacked on the sheet body 28 in the wiring sheet 26. They are bonded to each other. Thus, a laminate is formed. Then, cutting 90 and 92 of the laminate based on a cutting saw are performed. Thus, an intermediate assembly 44 is formed. The intermediate assembly 44 is bonded to the upper surface of the backing. And, an acoustic lens is bonded to the upper side of the intermediate assembly 44. The final assembly is manufactured through the process described above. The final assembly corresponds to the ultrasonic sensor. The final assembly is disposed within a housing.

[0077] In Figure 3 Fig. shows the wiring sheet 26 in an unfolded state. The wiring sheet 26 is composed of a sheet body 28, a stretching portion 30, and a stretching portion 23. The y-direction is the long side direction, and the x-direction is the short side direction. An oscillator array 16 is provided on the sheet body 28. The wiring sheet 26 has a lower side wiring pattern. The lower side wiring pattern includes a first lower side wiring pattern 100 and a second lower side wiring pattern 102.

[0078] The first lower side wiring pattern 100 is formed over the sheet body 28 and the stretching portion 30. In Figure 3 Fig., illustration of a part of the first lower side wiring pattern 100 is omitted. The second lower side wiring pattern 102 is formed over the sheet body 28 and the stretching portion 32. In Figure 3 Fig., illustration of a part of the second lower side wiring pattern 102 is omitted. A connection area 104 is provided at the end of the stretching portion 30. A connection area 106 is provided at the end of the stretching portion 32.

[0079] In Figure 4 Fig., a part of the sheet body 28 is shown. The upper side wiring pattern 72 is composed of a plurality of lines arranged in the long side direction. Specifically, the upper side wiring pattern 72 is composed of a plurality of upper side signal lines 94 and two upper side ground lines 96. However, in Figure 4 Fig., only one of the two upper side ground lines 96 is shown.

[0080] As described above, the lower side wiring pattern 70 is composed of the first lower side wiring pattern 100 and the second lower side wiring pattern 102. Specifically, the first lower side wiring pattern 100 is composed of a first lower side signal line group and a first lower side ground line, and the second lower side wiring pattern 102 is composed of a second lower side signal line group and a second lower side ground line. Hereinafter, the wiring patterns in the wiring sheet will be described in further detail.

[0081] A plurality of actual oscillators are composed of n actual oscillators numbered in sequence in the long side direction, from the first actual oscillator to the nth actual oscillator (n is an integer of 2 or more, for example, 60 or more and 300 or less). The n actual oscillators are connected to n upper side signal lines 94. Two virtual oscillators are connected to two upper side ground lines 96.

[0082] The first lower side wiring pattern 100 includes a plurality of first lower side signal lines 112 connected to the actual oscillators with odd numbers, and includes a first lower side ground line connected to one of the virtual oscillators. The first lower side signal line group is composed of a plurality of first lower side signal lines 112 connected to the actual oscillators with odd numbers.

[0083] The second lower side wiring pattern 102 includes a plurality of second lower side signal lines 113 connected to the actual oscillators with even numbers, and includes a second lower side ground line 114 connected to the other virtual oscillator. The second lower side signal line group is composed of a plurality of second lower side signal lines 113 connected to the actual oscillators with even numbers.

[0084] The via hole group 74 includes a first via hole column 115 and a second via hole column 116, and includes a plurality of ground via holes 78. The first via hole column 115 is composed of a plurality of signal via holes 76A connected to the actual oscillators with odd numbers, and the second via hole column 116 is composed of a plurality of signal via holes 76B connected to the actual oscillators with even numbers. The first via hole column 115 is formed along the diagonal direction of the sheet body 28, and the second via hole column 116 is also formed along the diagonal direction of the sheet body 28. However, the first metal via hole column 115 and the second metal via hole column 116 are in a relationship of being displaced from each other in the y direction.

[0085] In Figure 5 the piezoelectric layer array 118 and the wiring sheet 26 are shown. The piezoelectric layer array 118 is made by cutting 122 and is composed of a plurality of piezoelectric layers arranged in the long side direction. Specifically, the piezoelectric layer array 118 includes a plurality of piezoelectric layers (actual piezoelectric layers) 46 and two virtual piezoelectric layers 54. A ground film 18 is provided on the upper side of the piezoelectric layer array 118. However, in Figure 5 it schematically shows the ground film 18.

[0086] The wiring sheet 26 includes a lower side wiring pattern 70 and an upper side wiring pattern 72. In Figure 5 it shows the ground line (second lower side ground line) 114 in the lower side wiring pattern 70. The ground line 114 is connected to the upper side ground line 96 via the ground via hole 78. The upper side ground line 96 is connected to the ground film 18 via a virtual reflection layer and a virtual piezoelectric layer 54 not shown.

[0087] In Figure 6The grounded film 18 in the deployed state is shown. The grounded film 18 is prone to deformation. The grounded film 18 is composed of a film main body 140 and a pair of film end portions 142A and 142B connected to both sides in the short side direction of the film main body 140. The symbols 124 and 126 respectively represent bending lines.

[0088] The film main body 140 has a strip column 128 composed of a plurality of strips arranged in the long side direction. The strip column 128 includes a plurality of strips 130 joined to the upper surface electrodes of a plurality of piezoelectric layers (actual piezoelectric layers) 46 and two strips 132 joined to the upper surface electrodes of two virtual piezoelectric layers 54.

[0089] The film main body 140 has a plurality of openings 134 corresponding to a plurality of first slits and two openings 136 corresponding to two second slits. The plurality of openings 134 and 136 are formed by cutting the laminate. The symbol 138 represents the cutting depth. When manufacturing the assembly, the two film end portions 142A and 142B can be attached to two sides of the backing.

[0090] In Figures 7 - 9 several wiring patterns are shown. In each figure, #1 represents the first upper side signal line connected to the first oscillator (actual oscillator), and #2 represents the second upper side signal line connected to the second oscillator (actual oscillator). The same applies to #3, #4,....

[0091] In Figure 7 a first example of the wiring pattern is shown. The upper side wiring pattern 144 includes a plurality of upper side signal lines 145 arranged in the long side direction (y direction). The lower side wiring pattern 146 is divided into a first portion 148 and a second portion 150 arranged in the short side direction (x direction). In the first portion 148, there are included a plurality of lower side signal lines 147 pulled out to the right in Figure 7 In Figure 7 a plurality of lower side signal lines pulled out to the left. The via hole group 152 is composed of a plurality of holes 154 arranged in the diagonal direction of the sheet body.

[0092] In Figure 7 the symbol 158 represents the via hole pitch. θ1 represents the tilt angle of the via hole group 152.

[0093] In Figure 8A second example of a wiring pattern is shown. The upper wiring pattern 160 includes a plurality of upper signal lines 161 arranged in the long side direction (y direction). The lower wiring pattern 162 includes a plurality of lower signal lines arranged in the short side direction. More specifically, the plurality of lower signal lines are composed of odd-numbered lower signal lines 163 and even-numbered lower signal lines 164. They are alternately arranged in the short side direction. The via hole group 168 is composed of a plurality of via holes arranged in the diagonal direction of the sheet body.

[0094] In Figure 8 , the symbol 172 represents the via hole pitch. θ2 represents the inclination angle of the via hole group 152. According to Figure 8 the second example shown, compared with the first example above, the via hole pitch 172 can be increased, that is, the inclination angle θ2 can be decreased. Therefore, according to the second example, the width of the wiring sheet in the x direction can be decreased.

[0095] In Figure 9 a third example of a wiring pattern is shown. The upper wiring pattern 180 includes a plurality of upper signal lines 190 and two upper ground lines 192 arranged in the long side direction. However, in Figure 9 , only one of the two upper ground lines 192 is shown.

[0096] The lower wiring pattern 182 includes a first lower wiring pattern 186 and a second lower wiring pattern 188. The first lower wiring pattern 186 includes a plurality of lower signal lines 187 and a lower ground line. The second lower wiring pattern 188 includes a plurality of lower signal lines 189 and a lower ground line 200.

[0097] If described in more detail, the lower wiring pattern 182 includes n lower signal lines from the first lower signal line to the nth lower signal line. The n lower signal lines are connected to n oscillators (actual oscillators). The odd-numbered lower signal lines 187 are connected to odd-numbered oscillators (actual oscillators). The even-numbered lower signal lines 189 are connected to even-numbered oscillators (actual oscillators). The odd-numbered lower signal lines 187 and the even-numbered lower signal lines are alternately arranged in the short side direction.

[0098] The via hole group 184 is composed of a first via hole column 194 and a second via hole column 196. The first communication via hole column is composed of odd-numbered first signal vias A1, A3, A5, A7, A9,... connected to the odd-numbered lower signal lines 187. The second communication via hole column 196 is composed of even-numbered second signal vias A2, A4, A6, A8,... connected to the even-numbered lower signal lines 189.

[0099] The first through-hole row 194 and the second through-hole row 196 are formed along the diagonal direction of the sheet body. The first through-hole row 194 and the second through-hole row 196 are offset in the y direction (reference sign 196). It can also be said that they are offset in the x direction. From the first signal through-hole to the nth signal through-hole, n signal through-holes are arranged in a Z-shaped pattern. In addition, A0 represents a ground through-hole. One upper side ground wire 192 can also be connected to one or more lower side ground wires via a plurality of ground through-holes.

[0100] In the case of adopting the third example, compared with the second example above, the pitch between through-holes can be further increased, that is, the inclination angles of the first through-hole row 194 and the second through-hole row 196 can be made smaller. Therefore, according to the third example, the width of the wiring sheet in the x direction can be further reduced. And according to the third example, it is also easy to reduce the pitch between oscillators.

[0101] In Figure 10 shows a manufacturing method of an ultrasonic probe according to an embodiment. In S10, a reflective material plate, a piezoelectric material plate, a ground film, and one or more matching material plates are laminated on the sheet body of the wiring sheet, and they are bonded to each other. Thus, a laminate is fabricated on the wiring sheet.

[0102] In S12, the laminate is cut. Thus, an oscillator array is fabricated from the laminate. An intermediate assembly is composed of the wiring sheet and the oscillator array. In S14, the intermediate assembly is bonded to the upper surface of the backing. Moreover, an acoustic lens is bonded to the upper side of the oscillator array. Thus, an assembly is fabricated. A cable group is connected to the two stretching portions in the assembly. In S16, the assembly is disposed in a housing. Thus, the Figure 1 shown ultrasonic probe is formed.

[0103] According to the above embodiment, through the virtual oscillators, the ground wiring can be easily and reliably performed. Therefore, an oscillator array with good acoustic characteristics can be realized. In the above embodiment, in the oscillator array, two virtual oscillators are provided on both sides in the long side direction of the effective portion, so the physical strength of the oscillator array can be improved. In particular, the advantage that oscillator collapse is not likely to occur at both ends of the oscillator array can be obtained. Moreover, in the above embodiment, the odd-numbered lower side signal lines and the even-numbered lower side signal lines are alternately arranged in the wiring sheet, so the crosstalk of the electrical signals in the wiring sheet can be reduced. Regarding the characteristic matters related to the wiring pattern in the wiring sheet, they can also be adopted in an ultrasonic probe without virtual oscillators.

Claims

1. An ultrasonic probe, characterized in that, Comprising: An oscillator array including a plurality of actual oscillators each having a plurality of actual piezoelectric layers and a virtual oscillator having a virtual piezoelectric layer; A ground film disposed on the upper side of the plurality of actual piezoelectric layers and the virtual piezoelectric layer and electrically connected to a plurality of ground electrodes of the plurality of actual piezoelectric layers and the upper surface electrode of the virtual piezoelectric layer; and A wiring sheet disposed on the lower side of the oscillator array and having a plurality of signal lines electrically connected to a plurality of signal electrodes of the plurality of actual piezoelectric layers and a ground line electrically connected to the ground film, The virtual oscillator has a conductive portion including the virtual piezoelectric layer, and the conductive portion is disposed between the ground film and the wiring sheet, The ground film and the ground line are electrically connected via the conductive portion.

2. The ultrasonic probe according to claim 1, wherein The virtual piezoelectric layer has the upper surface electrode, the lower surface electrode, and side electrodes connected to the upper surface electrode and the lower surface electrode.

3. The ultrasonic probe according to claim 1, wherein The plurality of actual oscillators have a plurality of actual reflective layers having conductivity disposed on the lower side of the plurality of actual piezoelectric layers, The conductive portion has a virtual reflective layer having conductivity disposed on the lower side of the virtual oscillator.

4. The ultrasonic probe according to claim 1, wherein The oscillator array has a long side direction, The width of the virtual oscillator in the long side direction is greater than the width of each actual oscillator in the long side direction.

5. The ultrasonic probe according to claim 1, wherein The oscillator array includes: An effective portion composed of the plurality of actual oscillators and a plurality of first slits for separating each actual oscillator from other actual oscillators; and A second slit disposed between the effective portion and the virtual oscillator, The oscillator array has a long side direction, The width of the second slit in the long side direction is greater than the width of each first slit in the long side direction.

6. The ultrasonic probe according to claim 1, wherein The ground film includes: A film main body having a plurality of strips electrically joined to the plurality of ground electrodes and the upper surface electrode; and A pair of film end portions connected to the plurality of strips.

7. The ultrasonic probe according to claim 1, wherein The oscillator array has a long side direction and a short side direction intersecting the long side direction, The wiring sheet includes: An upper side wiring pattern having a plurality of upper side signal lines electrically connected to a plurality of signal electrodes of the plurality of actual oscillators and arranged in the long side direction and an upper side ground line electrically connected to the lower surface electrode of the virtual oscillator; A lower side wiring pattern having a plurality of lower side signal lines and a lower side ground line arranged in the short side direction; and A through-hole group having a plurality of signal through-holes connecting the plurality of upper side signal lines and the plurality of lower side signal lines and a ground through-hole electrically connecting the upper side ground line and the lower side ground line.

8. The ultrasonic probe according to claim 7, wherein The wiring sheet includes: A sheet body is provided on the lower side of the oscillator array and has one end and the other end separated in the long side direction; A first stretching portion is pulled out from the one end of the sheet body; and A second stretching portion is pulled out from the other end of the sheet body, The plurality of actual oscillators are n actual oscillators from the first actual oscillator to the nth actual oscillator arranged in serial order in the long side direction, The plurality of lower side signal lines include: A first lower side signal line group is electrically connected to the actual oscillators with odd numbers among the n actual oscillators and is provided over the sheet body and the first stretching portion; and A second lower side signal line group is electrically connected to the actual oscillators with even numbers among the n actual oscillators and is provided over the sheet body and the second stretching portion.

9. The ultrasonic probe according to claim 8, wherein The plurality of signal through holes have: A first signal through hole row connected to the first lower side signal line group; and A second signal through hole row connected to the second lower side signal line group, The first signal through hole row is aligned along the diagonal direction of the sheet body, The second signal through hole row is displaced from the first signal through hole row and is aligned along the diagonal direction.

10. The ultrasonic probe according to claim 1, characterized in that, Comprising: A first assembly composed of the oscillator array, the ground film, and the wiring sheet; A backing is provided on the lower side of the first assembly and has a first end portion and a second end portion separated in the long side direction; And A housing accommodates a second assembly composed of the first assembly and the backing, The wiring sheet includes: A sheet body is provided on the lower side of the oscillator array and has one end and the other end separated in the long side direction; A first stretching portion is pulled out from the one end of the sheet body; A second stretching portion is pulled out from the other end of the sheet body, In the housing, a lower side space is formed under the backing, After the first stretching portion enters the lower side space through the space adjacent to the first end portion, it turns in a U shape in the lower side space, The second stretching portion enters the lower side space through the space adjacent to the second end portion, The end portion of the first stretching portion and the end portion of the second stretching portion overlap in the lower side space.

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