JP2005323630A - Ultrasonic probe and ultrasonic diagnostic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic probe minimizing an effect on acoustic matching by reducing acoustic impedance of an electrode of a flexible printed circuit board. <P>SOLUTION: A lead out electrode 61 for the flexible printed circuit board is so formed that a metal 63 is linearly patterned on a base material 62 composed of a resin orthogonally to the scanning direction. An epoxy resin with acoustic impedance of approximately 3 Mrayl or the like is used as the resin of the base material 62. The electrode 61 is connected to an electrode of a piezoelectric vibrator. The metal 63 is linearly patterned to reduce the occupation rate of the metal 63. If the rate of the metal 63 having high acoustic impedance is reduced, the acoustic impedance of the lead out electrode 61 is reduced by the rate. Consequently, the acoustic matching between the piezoelectric vibrator 3 and a subject is improved by compared with a case forming the electrode 61 of the metal alone. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ultrasonic probe characterized by acoustic matching with a subject and an ultrasonic diagnostic apparatus including the ultrasonic probe.

  2. Description of the Related Art There is known an ultrasonic diagnostic apparatus that scans an inside of a subject with ultrasonic waves and images an internal state of the subject based on a reception signal generated from a reflected wave from the inside of the subject. Such an ultrasonic diagnostic apparatus transmits ultrasonic waves into a subject using an ultrasonic probe including a piezoelectric vibrator, and receives reflected waves generated by acoustic impedance mismatches within the subject using the ultrasonic probe. Generate a received signal.

  The ultrasonic probe is arranged with a plurality of piezoelectric vibrators in the scanning direction that generate an ultrasonic wave by vibrating based on a transmission signal and generate a reception signal by receiving a reflected wave. Such a piezoelectric vibrator transmits, for example, an ultrasonic wave having a uniform rectangular sound pressure distribution in a direction orthogonal to the scanning direction, and gives a delay difference by an acoustic lens, whereby a predetermined depth in the subject is measured. That is the focus.

  The ultrasonic probe includes a back member and a piezoelectric vibrator arranged on the back member in a plurality of divided portions in the scanning direction. Furthermore, it has an acoustic matching layer that is divided and arranged in a plurality in the scanning direction on the piezoelectric vibrator, and an acoustic lens provided on the acoustic matching layer. For the purpose of achieving acoustic matching between the acoustic impedance of the piezoelectric vibrator and the acoustic impedance of the subject, the acoustic matching layer is formed of a plurality of layers (for example, Patent Document 1). For example, a first acoustic matching layer, a second acoustic matching layer provided on the first acoustic matching layer, and a third acoustic matching layer provided on the second acoustic matching layer It consists of. As the acoustic matching layer, the acoustic matching layer is better in the two layers than in the first layer, and the acoustic matching is further improved in the three layers. In such an ultrasonic probe, the piezoelectric vibrator transmits and receives ultrasonic waves through the acoustic matching layer.

  As described above, the acoustic matching between the piezoelectric vibrator and the subject is good when the difference between the acoustic impedance of the piezoelectric vibrator and the acoustic impedance of the subject is large. This is because the transmission loss of ultrasonic waves at the subject increases. This is because the ultrasonic wave cannot be efficiently transmitted to the subject, and an image with good image quality cannot be obtained.

  In such an ultrasonic probe, electrodes are baked on the upper and lower surfaces of the piezoelectric vibrator. Then, a flexible printed circuit board (FPC) for signal electrode extraction is bonded via an electrode between the backing material and the piezoelectric vibrator, and electrical wiring is drawn out by the flexible printed circuit board and connected to the ultrasonic diagnostic apparatus main body. Is done. In addition, a flexible printed board for grounding is bonded between the piezoelectric vibrator and the acoustic matching layer via an electrode. In the case where a conductive material is used for the acoustic matching layer, a ground printed flexible printed circuit board may be bonded between the acoustic matching layer and the acoustic lens. In addition, a ground drawing flexible substrate (FPC), a metal sheet, a thin plate, or the like is connected to the electrode for ground drawing.

JP 10-056694 A (paragraphs [0034]-[0039], FIG. 1)

  The flexible printed circuit board for extracting the signal electrode from the piezoelectric vibrator and the flexible printed circuit board for extracting the ground are required to have conductivity. Therefore, a metal electrode such as copper or gold is used for a portion connected to the electrode of the piezoelectric vibrator in the flexible printed board.

  However, when this metal electrode is disposed in a portion where ultrasonic waves propagate, that is, between the piezoelectric vibrator and the subject (living body) or between the piezoelectric vibrator and the back material, This causes an acoustic impedance mismatch.

  In general, the acoustic impedance of the piezoelectric vibrator is about 30 [Mrayl], and the acoustic impedance of the subject is about 1.5 [Mrayl]. On the other hand, the acoustic impedance of the metal used as an electrode of a flexible printed circuit board is as large as 40 to 60 [Mrayl]. Therefore, the effect of acoustic matching is reduced at the electrode portion of the flexible printed circuit board, and it becomes difficult to realize the intended characteristics in design.

  The present invention solves the above-described problems, and an ultrasonic probe having an electrode portion that can minimize the acoustic impedance of an electrode of a flexible printed circuit board as much as possible and minimize the effect on acoustic matching. The purpose is to provide. Accordingly, an object of the present invention is to provide an ultrasonic diagnostic apparatus that can efficiently transmit ultrasonic waves to a subject and obtain an image with good image quality.

  According to the first aspect of the present invention, an electrode is formed on both surfaces, and a voltage is applied by the electrode to transmit an ultrasonic wave in a direction orthogonal to the surface on which the electrode is formed. A first electrode connected to an electrode formed on one surface, and a second electrode connected to an electrode formed on the other surface of the both surfaces, the first electrode and the At least one of the second electrodes is an ultrasonic probe comprising a substrate made of resin and a metal regularly arranged on the substrate.

  The first electrode is, for example, an electrode formed on a flexible printed circuit board for signal extraction, and the second electrode is, for example, an electrode formed on a flexible printed circuit board for ground extraction. As the resin, for example, an epoxy resin, a polyimide resin, a urethane resin, or the like is used. Since these acoustic impedances are 2 to 3 [Mrayl], by using these resins for the first electrode or the second electrode, they are composed only of metal (acoustic impedance: 40 to 60 [Mrayl]). The acoustic impedance can be made smaller than that. Since the ultrasonic wave transmitted from the piezoelectric vibrator passes through the first electrode or the second electrode, the acoustic impedance of the first electrode and the second electrode is reduced to reduce the acoustic impedance between the piezoelectric vibrator and the subject. The acoustic matching between them can be improved. In addition, since the ultrasonic wave reflected from the subject also passes through the first electrode or the second electrode and is received by the piezoelectric vibrator, the acoustic impedance of the first electrode and the second electrode is reduced. In addition, acoustic matching between the piezoelectric vibrator and the subject can be improved.

  The invention according to claim 2 is the ultrasonic probe according to claim 1, wherein the metal is arranged in a line shape, a mesh shape, or a spot shape.

  Since the metal is regularly arranged as described above, the proportion of the metal in the first electrode or the second electrode is reduced, and the sound of the first electrode or the second electrode is reduced according to the proportion. Impedance decreases. Furthermore, since the acoustic impedance can be changed by changing the shape and ratio of the metal, the target acoustic impedance can be easily obtained.

  The invention according to claim 3 is the ultrasonic probe according to claim 1 or 2, wherein the resin has an acoustic impedance of 5 [Mrayl] or less.

  Invention of Claim 4 is an ultrasonic probe in any one of Claim 1 thru | or 3, Comprising: The said resin is an epoxy resin, a polyimide resin, or a urethane resin, It is characterized by the above-mentioned. It is.

  The invention according to claim 5 is the ultrasonic probe according to any one of claims 1 to 4, wherein the resin contains a conductive filler.

  A sixth aspect of the present invention is the ultrasonic probe according to any one of the first to fifth aspects, wherein the ultrasonic probe is formed on the other surface side of the piezoelectric vibrator than the piezoelectric vibrator. The resin layer has a low acoustic impedance, the first electrode is connected to an electrode formed on the one surface by a conductive adhesive, and the second electrode is connected to the resin layer by a conductive adhesive. It is connected to the electrode formed on the other surface via the.

  According to a seventh aspect of the present invention, ultrasonic waves are transmitted / received to / from a subject, and the ultrasonic probe according to any one of claims 1 to 6 is driven to drive the ultrasonic probe into the subject. Transmitting / receiving means for scanning the image, image processing means for generating an image of the subject based on a received signal obtained by scanning of the transmitting / receiving means, display means for displaying the image generated by the image processing means, It is an ultrasonic diagnostic apparatus characterized by having.

  When a voltage is applied to the ultrasonic probe, ultrasonic waves are transmitted or received. Then, an ultrasonic wave is transmitted to the subject, and a reflected wave is received to generate an image of the subject. At this time, by improving the acoustic matching between the piezoelectric vibrator and the subject, the transmission efficiency to the subject is improved.

  According to the ultrasonic probe of the first aspect, since the first electrode or the second electrode is made of a metal and a resin, it is possible to reduce the acoustic impedance thereof. As a result, the acoustic matching between the piezoelectric vibrator and the subject is good, and when used in an ultrasonic diagnostic apparatus, an ultrasonic image with good image quality can be obtained. Further, by forming both the first electrode and the second electrode from a metal and a resin, the acoustic impedance can be further reduced, and an ultrasonic image with higher image quality can be obtained. In addition, since the first electrode or the second electrode is formed of a resin and a metal, the adhesive strength is higher than that of the metal alone. As a result, the adhesive strength between the electrode and the piezoelectric vibrator is increased, and it is possible to reduce the cause of defects such as electrode peeling.

  Moreover, according to the ultrasonic probe of claim 2, the metal occupying ratio is reduced by arranging the metal constituting the first electrode or the second electrode in a line shape, a mesh shape, or a spot shape. And it becomes possible to make acoustic impedance small according to the ratio. As a result, the acoustic matching between the piezoelectric vibrator and the subject becomes good, and an ultrasonic image with good image quality can be obtained.

  According to the ultrasonic probe of claim 3, by setting the acoustic impedance of the resin constituting the first electrode or the second electrode to 5 [Mrayl] or less, the piezoelectric vibrator and the subject Therefore, it is possible to obtain an ultrasonic image with good image quality.

  Further, according to the ultrasonic probe of claim 4, by using an epoxy resin, a polyimide resin, or a urethane resin as a resin constituting the first electrode or the second electrode, the first electrode or the second electrode is used. The acoustic impedance of the second electrode can be reduced.

  In addition, according to the ultrasonic probe of the fifth aspect, it is possible to increase the conductivity of the resin by including a conductive filler in the resin constituting the first electrode or the second electrode. Even if a resin is used for the electrode, it is possible to improve electrical connection with the piezoelectric vibrator.

  According to the ultrasonic probe of the sixth aspect, even if the first electrode or the second electrode is made of a resin and a metal, they are connected to a piezoelectric vibrator or the like with a conductive adhesive. Therefore, electrical connection can be established between the piezoelectric vibrator.

  In addition, according to the ultrasonic diagnostic apparatus of the seventh aspect, by providing the ultrasonic probe according to any one of the first to sixth aspects, acoustic matching between the piezoelectric vibrator and the subject is improved. Therefore, the reflection loss of the ultrasonic wave can be reduced, and the ultrasonic wave can be efficiently transmitted to the subject. As a result, an image with good image quality can be obtained.

  Hereinafter, an ultrasonic probe according to an embodiment of the present invention will be described with reference to FIGS. 1 to 9.

(Constitution)
The configuration of the ultrasonic probe according to the embodiment of the present invention will be described with reference to FIGS. 1 and 7 are perspective views showing a schematic configuration of an ultrasonic probe according to an embodiment of the present invention. 2 to 6 are views showing the shape of the electrode portion of the flexible printed circuit board connected to the ultrasonic probe according to the embodiment of the present invention. The ultrasonic probe includes a head side and a cable side. FIGS. 1 and 7 show the head side of the ultrasonic probe.

  As shown in FIG. 1, the ultrasonic probe 1 according to this embodiment is provided with a piezoelectric vibrator 3 arranged on a back material 2 so as to be divided into a plurality of parts in the scanning direction. Furthermore, a conductive acoustic matching layer 4 that is divided and arranged in the scanning direction is disposed on the piezoelectric vibrator 3, and an acoustic lens 5 is disposed on the acoustic matching layer 4. The acoustic matching layer 4 includes a plurality of layers. The first acoustic matching layer 4a, the second acoustic matching layer 4b provided on the first acoustic matching layer 4a, and the second acoustic matching layer 4a. And a third acoustic matching layer 4c provided on the matching layer 4b. The description on the cable side is omitted.

  The backing material 2 attenuates and absorbs ultrasonic vibration components that are not necessary for image extraction of the ultrasonic diagnostic apparatus among ultrasonic vibrations oscillated from the piezoelectric vibrator 3 and ultrasonic vibrations at the time of reception.

The piezoelectric vibrator 3 is made of, for example, a ceramic material such as lead zirconate titanate Pb (Zr, Ti) O ₃ , lithium niobate (LiNbO ₃ ), barium titanate (BaTiO ₃ ), or lead titanate (PbTiO ₃ ). .

  Further, on the surface of the piezoelectric vibrator 3, a planar electrode 31 is formed on the surface in contact with the back material 2, and a planar electrode 32 is formed on the surface in contact with the matching layer 4a. A voltage for causing piezoelectric vibration is applied to the piezoelectric vibrator 3 by this electrode, and converted into mechanical vibration by the occurrence of a piezoelectric phenomenon. Then, ultrasonic waves are transmitted in a direction orthogonal to the electrodes 31 and 32 by the piezoelectric phenomenon.

  Further, by forming the acoustic matching layer 4 into a plurality of layer structures, the generation of signal loss due to the difference in acoustic impedance with the body surface of the subject combined with the acoustic lens 5 is suppressed.

  The acoustic lens 5 contacts the body surface of the subject and mediates transmission / reception of ultrasonic waves. By this acoustic lens 5, an acoustic focal point in the slice direction is formed at a predetermined depth from the body surface. The acoustic focus in the scanning direction is established by switching and controlling the timing of transmission and reception of the plurality of piezoelectric vibrators 3 arranged in a strip shape in the scanning direction.

  Since the piezoelectric vibrator 3 and the acoustic matching layers 4a to 4c are divided and arranged in the scanning direction, the ultrasonic probe 1 according to this embodiment is a one-dimensional array ultrasonic probe.

  Further, a flexible printed circuit board 6 a for drawing out signal electrodes is bonded between the backing material 2 and the piezoelectric vibrator 3 via an electrode 31. Further, a flexible printed board 6b for grounding is bonded between the piezoelectric vibrator 3 and the acoustic matching layer 4a via an electrode 32. An electrode connected to the electrode 31 of the piezoelectric vibrator 3 is formed on the flexible printed board 6a, and an electrode connected to the electrode 32 of the piezoelectric vibrator 3 is formed on the flexible printed board 6b. These flexible printed boards 6a and 6b are bonded to the piezoelectric vibrator 3 with a conductive adhesive. The conductive adhesive is obtained by blending conductive fine particles such as gold, silver, nickel, and carbon into a resin such as an epoxy resin, a urethane resin, or an acrylic resin. The electrode formed on the flexible printed circuit board 6a corresponds to the “first electrode” of the present invention, and the electrode formed on the flexible printed circuit board 6b corresponds to the “second electrode” of the present invention.

  The flexible printed board 6 a is connected to the electrode 31 of the piezoelectric vibrator 3, thereby drawing an electrical wiring from the electrode 31 and connecting the ultrasonic probe 1 to the ultrasonic diagnostic apparatus main body. Signals are transmitted and received between the ultrasonic probe 1 and the ultrasonic diagnostic apparatus body by the flexible printed circuit board 6a. Further, the flexible printed circuit board 6b is connected to the electrode 32 of the piezoelectric vibrator 3 so that electric wiring is drawn out from the electrode 32 and connected to the ground. The flexible wiring board 6a serves as a lead wire. The configuration of the electrodes for drawing out the flexible wiring boards 6a and 6b will be described in detail later.

  By applying a voltage to the piezoelectric vibrator 3, an ultrasonic wave is generated by a piezoelectric phenomenon, and the ultrasonic wave is irradiated toward a diagnosis target region of the subject. In the ultrasonic probe according to the present embodiment, an ultrasonic wave is transmitted in a direction orthogonal to the electrode 31 and the electrode 32 by applying a voltage to the piezoelectric vibrator by the electrode 31 and the electrode 32. The ultrasonic wave transmitted from the piezoelectric vibrator passes through the electrode of the flexible printed circuit board 6b, the acoustic matching layers 4a to 4c, and further passes through the acoustic lens 5 and is irradiated to the subject. The irradiated ultrasonic waves are reflected from a plurality of boundary surfaces having different acoustic impedances. The reflected ultrasonic waves pass through the acoustic lens 5, the acoustic matching layers 4 a to 4 c, and the flexible printed board 6 b and are received by the piezoelectric vibrator 3. And the internal state of a diagnostic object site | part is extracted as an image by converting into an electrical signal.

  Next, the shape of the signal electrodes or grounding electrodes formed on the flexible printed boards 6a and 6b will be described with reference to FIGS. The electrodes for pulling out the flexible printed boards 6 a and 6 b shown in FIGS. 2 to 6 are connected to the electrode 31 or the electrode 32 formed on the piezoelectric vibrator 3.

  FIG. 2 shows an electrode that is linearly patterned in a direction orthogonal to the scanning direction. 2A is a top view of the electrode viewed from the transmission direction of the ultrasonic probe, and FIG. 2B is a front view viewed from the scanning direction of the ultrasonic probe.

  The electrodes 61 for drawing out the flexible printed boards 6a and 6b are formed by patterning a metal 63 linearly on a resin base material 62 in a direction perpendicular to the scanning direction. As the resin of the base material 62, for example, an epoxy resin having an acoustic impedance of about 3 [Mrayl], a polyimide resin of about 3 [Mrayl], or a urethane resin of about 2 [Mrayl] is used. In addition, the resin used in the present invention is not limited to the above-described resin, and the effects of the present invention can be obtained if the resin has a low acoustic impedance, for example, a resin having an acoustic impedance of about 5 [Mrayl] or less. For the metal 63, gold (Au), copper (Cu), or the like is used.

  The metal 63 is connected to the electrode 31 or the electrode 32 of the piezoelectric vibrator 3, and the piezoelectric vibrator 3 and the flexible printed boards 6a and 6b are electrically connected. Since the flexible printed boards 6a and 6b are bonded to the piezoelectric vibrator 3 with a conductive adhesive, the flexible printed boards 6a and 6b can be electrically connected to the electrode 31 or the electrode 32 of the piezoelectric vibrator 3.

  Thus, by patterning the metal 63 in a straight line, the proportion of the metal 63 is reduced. If the proportion of the metal 63 having a high acoustic impedance is reduced, the acoustic impedance of the extraction electrode 61 is reduced accordingly. When ultrasonic waves are transmitted and received, they pass through the electrodes 61 of the flexible printed boards 6a and 6b. Therefore, if the acoustic impedance of the electrodes 61 is reduced, the piezoelectric vibrator is compared with the case where the electrodes 61 are made of only metal. It is possible to improve the acoustic matching between 3 and the subject.

  Further, the acoustic impedance of the electrode 61 can be changed by changing the pitch between the metals 63 and the width of the metal 63. For example, the acoustic impedance of the electrode 61 can be reduced by increasing the pitch between the metals 63 and reducing the width of the metal 63. On the other hand, if the pitch is reduced and the width of the metal 63 is increased, the acoustic impedance of the electrode 61 can be increased. Thus, the required acoustic impedance can be obtained by changing the dimension of the metal 63.

  Moreover, you may use the flexible printed circuit board which has an electrode of a shape as shown in FIG. FIG. 3 shows electrodes that are linearly patterned in the scanning direction. 3A is a top view of the electrode viewed from the transmission direction, and FIG. 3B is a front view viewed from the scanning direction.

  In the lead electrode 61 shown in FIG. 3, a metal 63 is linearly patterned in a scanning direction on a base material 62 made of resin. The resin of the base material 62 and the material of the metal 63 are the same as those of the extraction electrode shown in FIG.

  Thus, by patterning the metal 63 linearly in the scanning direction, the ratio of the metal 63 to the base material 62 made of resin is reduced, and the acoustic impedance of the electrode 61 is reduced, similarly to the electrode shown in FIG. Can do. As a result, it is possible to improve acoustic matching between the piezoelectric vibrator 3 and the subject.

  Moreover, you may use the flexible printed circuit board which has an electrode of a shape as shown in FIG. FIG. 4 shows an electrode patterned in a mesh pattern. 4A is a top view of the electrode viewed from the transmission direction, and FIG. 3B is a front view viewed from the scanning direction.

  In the lead-out electrode 61 shown in FIG. 4, a metal 63 is patterned in a mesh pattern on a base material 62 made of resin. Thus, by patterning the metal 63 in a mesh pattern, the ratio of the metal 63 to the base 62 made of resin can be reduced, and the acoustic impedance of the electrode 61 can be reduced, similarly to the electrodes shown in FIGS. it can. As a result, it is possible to improve acoustic matching between the piezoelectric vibrator 3 and the subject.

  Alternatively, a flexible printed circuit board having an electrode shape as shown in FIG. 5 may be used. FIG. 5 shows electrodes patterned linearly obliquely with respect to the scanning direction. FIG. 5A is a top view of the electrode viewed from the transmission direction, and FIG. 5B is a front view viewed from the scanning direction.

  In the lead-out electrode 61 shown in FIG. 5, a metal 63 is patterned on a base material 62 in a straight line obliquely with respect to the scanning direction. By patterning the metal 63 obliquely in this way, the proportion of the metal 63 is reduced, the acoustic impedance of the electrode 61 can be reduced, and the acoustic matching between the piezoelectric vibrator 3 and the subject is improved. It becomes possible.

  Moreover, you may use the flexible printed circuit board which has an electrode of a shape as shown in FIG. FIG. 6 shows an electrode patterned in a spot shape. FIG. 6A is a top view of the electrode viewed from the transmission direction, and FIG. 6B is a front view viewed from the scanning direction.

  In the lead electrode 61 shown in FIG. 6, a metal 63 is patterned in a spot shape on a base material 62. Since the metal 63 is patterned in spots like this, the proportion of the metal 63 is reduced, the acoustic impedance of the electrode 61 can be reduced, and the acoustic matching between the piezoelectric vibrator 3 and the subject is achieved. It becomes possible to improve.

  As described above, the electric wiring drawing electrode 61 formed on the flexible printed circuit boards 6a and 6b is composed of the base material 62 made of resin and the metal 63, and the metal 63 having a large acoustic impedance is patterned to form the metal. By reducing the ratio 63, the acoustic impedance of the extraction electrode 61 can be reduced. As a result, the acoustic matching between the piezoelectric vibrator 3 and the subject can be improved even through the flexible wiring boards 6a and 6b.

  If the ratio of the metal 63 is reduced, the electrical connection between the electrodes 31 and 32 formed on both surfaces of the piezoelectric vibrator 3 and the electrodes 61 of the flexible wiring boards 6a and 6b becomes a problem. However, the electrical connection between the piezoelectric vibrator 3 and the flexible wiring boards 6a and 6b can be improved by connecting the flexible wiring boards 6a and 6b to the piezoelectric vibrator 3 with a conductive adhesive. In order to improve the conductivity, a conductive filler such as a carbon filler may be included in the base material 62 made of resin. Even when the conductive filler is contained in the base material 62 as described above, the acoustic impedance of the electrode 61 can be reduced if the ratio of the metal 63 is reduced.

  The configuration of the extraction electrode 61 shown in FIGS. 2 to 6 is only an example. In order to reduce the acoustic impedance of the electrode 61, the ratio of the metal 63 may be reduced. Therefore, the shape of the metal 63 may be other than the shape shown above. For example, the metal 63 may be formed in a curved shape instead of a linear shape. Further, a plurality of rectangular or triangular points may be formed instead of the spots. Even if the metal 63 is patterned in this way, the acoustic impedance of the electrode 61 can be reduced, and the acoustic matching between the piezoelectric vibrator 3 and the subject can be improved.

  In addition, since the electrodes 61 of the flexible printed boards 6a and 6b are made of a base material 62 made of resin and a metal 63, the electrodes 61 and 32 of the piezoelectric vibrator 3 are compared with the case where the electrodes are made of only metal. Adhesive strength increases. When the electrode 61 is formed of only metal, the adhesive strength is weakened and there is a problem that the electrode peels off. However, the use of a resin for the electrode 61 increases the strength, and it is possible to suppress the occurrence of electrode peeling. . In addition, in the case of only metal, it is easy to peel off, and thus it is difficult to adhere to the electrodes 31 and 32 of the piezoelectric vibrator 3. However, by using a resin, it becomes difficult to peel off, and it can be easily adhered to that extent. It becomes possible.

  Further, as shown in the perspective view of FIG. 7, a flexible printed circuit board 6b for grounding may be provided between the acoustic matching layer 4 and the acoustic lens 5. Specifically, a flexible substrate 6 b is provided between the acoustic matching layer 4 c and the acoustic lens 5.

  For example, the acoustic matching layers 4a to 4c can be made conductive by including a conductive filler such as a carbon filler in the acoustic matching layers 4a to 4c. Therefore, even if the flexible printed circuit board 6b for grounding is disposed between the acoustic matching layer 4c and the acoustic lens 5, electrical connection can be established between the flexible printed circuit board 6b and the electrode 32 of the piezoelectric vibrator 3. .

  Further, instead of including the carbon filler, plating may be performed around the acoustic matching layers 4a to 4c, and conduction may be established between the flexible printed board 6b and the piezoelectric vibrator 3 by the plating.

  In the ultrasonic probe shown in FIG. 7 as well, the connection between the piezoelectric vibrator 3 and the flexible printed board 6a is made through a conductive adhesive, and the connection between the acoustic matching layer 4c and the flexible printed board 6b is also conductive. This is done via an adhesive.

(Example)
Next, an example of the ultrasonic probe according to this embodiment will be described with reference to FIG. FIG. 8 shows an example of a simulation in which a frequency spectrum at the time of ultrasonic wave transmission / reception is calculated. In the figure, the horizontal axis represents the frequency [MHz] of the ultrasonic wave, and the vertical axis represents the acoustic intensity [dB].

  In FIG. 8, spectrum A is a spectrum when the flexible printed circuit boards 6a and 6b are made of only a resin, and the acoustic impedance is set to about 3 [Mrayl] by using, for example, an epoxy resin. The spectrum B is a spectrum when the electrodes of the flexible printed circuit boards 6a and 6b are made of only a metal such as gold or copper, and the acoustic impedance is 40 to 60 [Mrayl].

  Spectra C and D are flexible printed boards 6a and 6b in the present embodiment, and the electrodes are formed from a metal and a resin. The metal 63 on the electrodes 61 of the flexible printed boards 6a and 6b is patterned as described above. The patterning shape may be any of the shapes shown in FIGS. In addition, by changing the pattern of the metal 63 formed on the base material 62 made of resin, the acoustic impedance of the extraction electrode 63 made of resin and metal can be changed. That is, when the pattern of the metal 63 is changed, the ratio of the metal 63 in the electrode 61 can be changed, and the acoustic impedance of the electrode 61 is changed according to the ratio of the metal 63.

  Thus, the spectra C and D are obtained by changing the pattern of the metal 63 and changing the ratio of the metal 63 in the electrode 61. The spectrum C is a spectrum when the acoustic impedance of the electrode 61 is 50% of the case where the electrode 61 is made of only metal. The spectrum D is a spectrum when the acoustic impedance of the electrode 61 is 10% of the case where the electrode 61 is made of only metal.

  For example, if the electrode 61 is made of only a metal having an acoustic impedance of about 40 [Mrayl], the acoustic impedance of the electrode 61 is naturally about 40 [Mrayl]. On the other hand, when the electrode 61 is formed of the base material 62 made of resin and the patterned metal 63, the acoustic impedance of the electrode 61 is 50% or 10%, that is, about 20 [Mrayl] or about 4 [Mrayl]. . In other words, the metal 63 is patterned to reduce the proportion of the metal 63 so that the acoustic impedance of the electrode 61 is about 20 [Mrayl] or about 4 [Mrayl]. The patterning shape may be any of the shapes shown in FIGS. The spectrum of the electrode 61 thus obtained is a spectrum C and a spectrum D. The spectrum C is a spectrum of 50% (about 20 [Mrayl]), and the spectrum D is a spectrum of 10% (about 4 [Mrayl]).

  If the flexible printed circuit boards 6a and 6b are made of only metal, the acoustic matching between the piezoelectric vibrator 3 and the subject is deteriorated. Therefore, as in the spectrum B, the shape of the frequency spectrum is distorted and the bandwidth is reduced. It is done. On the other hand, when the acoustic impedance is reduced to 50% and 10%, the distortion of the shape of the frequency spectrum is reduced as in the spectra C and D, and the reduction in bandwidth can be suppressed. Further, since the spectrum D has almost the same curve as that of the resin alone, the acoustic wave between the piezoelectric vibrator 3 and the subject is formed by forming electrodes of such a spectrum on the flexible printed boards 6a and 6b. Good alignment can be achieved.

(Production method)
Next, a method for manufacturing the ultrasonic probe according to this embodiment will be described. The ultrasonic probe 1 shown in FIG. 1 is manufactured by the method described below. First, the piezoelectric vibrator 3 is bonded onto the back material 2 via the flexible printed board 6a. Further, the flexible printed board 6b is bonded onto the piezoelectric vibrator 3. The flexible printed boards 6a and 6b and the piezoelectric vibrator 3 are bonded with a conductive adhesive. And the acoustic matching layers 4a-4c are adhere | attached on the flexible printed circuit board 6b, and it dices with a desired pitch, and produces the acoustic matching layers 4a-4c divided | segmented into multiple in the scanning direction. Further, an acoustic lens 5 is adhered thereon to produce the ultrasonic probe 1.

  Further, the ultrasonic probe shown in FIG. 7 is manufactured by the method described below. The piezoelectric vibrator 3 is bonded via the flexible printed circuit board 6a on the back material 2, and the conductive acoustic matching layers 4a to 4c are bonded thereon. For example, the acoustic matching layers 4a to 4c can be made conductive by including conductive fillers such as carbon fillers in the acoustic matching layers 4a to 4c made of resin. Thereafter, the piezoelectric vibrator 3 and the acoustic matching layers 4a to 4c are diced at a desired pitch, and the piezoelectric vibrator 3 and the acoustic matching layers 4a to 4c divided into a plurality in the scanning direction are manufactured. Then, the flexible wiring board 6b is bonded onto the acoustic matching layer 4c, and the acoustic lens 5 is bonded onto the flexible wiring board 6b, thereby producing an ultrasonic probe.

  Next, an ultrasonic diagnostic apparatus including the ultrasonic probe according to the embodiment of the present invention will be described with reference to FIG. FIG. 9 is a block diagram showing a configuration of a main part of the ultrasonic diagnostic apparatus according to the embodiment of the present invention.

  The ultrasonic diagnostic apparatus 90 includes an ultrasonic probe 91, a transmission / reception circuit 92, a transmission / reception control circuit 93, an image data conversion circuit 94, a display control circuit 95, a monitor 96, and a control circuit 97.

  The ultrasonic probe 91 transmits ultrasonic waves to a subject such as a patient, and receives the ultrasonic waves reflected by the subject as echo signals. The ultrasonic probe 91 according to the embodiment of the present invention is used for the ultrasonic probe 91, and the flexible printed boards 6a and 6b are connected thereto.

  The transmission / reception circuit 92 supplies an electrical signal to the ultrasonic probe 91 via the flexible printed board 6a to generate an ultrasonic wave, and receives an echo signal received by the ultrasonic probe 91. The transmission / reception control circuit 93 performs transmission / reception control of the transmission / reception circuit 92.

  The image data conversion circuit 94 converts the echo signal received by the transmission / reception circuit 92 into ultrasonic image data of the subject. The display control circuit 95 controls the monitor 96 to display the ultrasonic image data converted by the image data conversion circuit 94. The control circuit 97 controls the entire ultrasound diagnostic apparatus 90.

  A transmission / reception control circuit 93, an image data conversion circuit 94, and a display control circuit 95 are connected to the control circuit 97, and the control circuit 97 controls operations of these units.

  Then, an electrical signal is applied to the piezoelectric vibrator of the ultrasonic probe 91 to transmit an ultrasonic wave to the subject, and a reflected wave caused by an acoustic impedance mismatch inside the subject is received by the ultrasonic probe 91.

  According to the ultrasonic diagnostic apparatus including the ultrasonic probe 1 according to the embodiment of the present invention, the acoustic matching between the piezoelectric vibrator 3 and the subject can be improved, so that the ultrasonic reflection loss is reduced. Therefore, it is possible to efficiently transmit ultrasonic waves to the subject. As a result, an image with good image quality can be obtained.

1 is a perspective view showing a schematic configuration of an ultrasonic probe according to an embodiment of the present invention. It is a figure which shows an example of the electrode of the flexible printed circuit board connected to the ultrasonic probe which concerns on embodiment of this invention. It is a figure which shows an example of the electrode of the flexible printed circuit board connected to the ultrasonic probe which concerns on embodiment of this invention. It is a figure which shows an example of the electrode of the flexible printed circuit board connected to the ultrasonic probe which concerns on embodiment of this invention. It is a figure which shows an example of the electrode of the flexible printed circuit board connected to the ultrasonic probe which concerns on embodiment of this invention. It is a figure which shows an example of the electrode of the flexible printed circuit board connected to the ultrasonic probe which concerns on embodiment of this invention. It is a perspective view which shows schematic structure of another ultrasonic probe which concerns on embodiment of this invention. It is a graph which shows the frequency spectrum of the ultrasonic probe which concerns on embodiment of this invention. 1 is a block diagram showing a schematic configuration of an ultrasonic diagnostic apparatus provided with the ultrasonic probe of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ultrasonic probe 2 Back material 3 Piezoelectric vibrator 4a, 4b, 4c Acoustic matching layer 5 Acoustic lens 6a, 6b Flexible printed circuit board 31, 32 Electrode 90 Ultrasonic diagnostic apparatus

Claims (7)

Electrodes are formed on both surfaces, and a piezoelectric vibrator that transmits ultrasonic waves in a direction orthogonal to the surface on which the electrodes are formed when voltage is applied by the electrodes;
A first electrode connected to an electrode formed on one of the two surfaces;
A second electrode connected to an electrode formed on the other surface of the both surfaces,
At least one of the first electrode and the second electrode is made of a resin substrate and a metal regularly disposed on the substrate. The ultrasonic probe according to claim 1, wherein the metal is arranged in a line shape, a mesh shape, or a spot shape. The ultrasonic probe according to claim 1, wherein the resin has an acoustic impedance of 5 [Mrayl] or less. The ultrasonic probe according to any one of claims 1 to 3, wherein the resin is an epoxy resin, a polyimide resin, or a urethane resin. The ultrasonic probe according to claim 1, wherein the resin contains a conductive filler. A resin layer formed on the other surface side of the piezoelectric vibrator and having a smaller acoustic impedance than the piezoelectric vibrator;
The first electrode is connected to an electrode formed on the one surface by a conductive adhesive,
6. The second electrode according to claim 1, wherein the second electrode is connected to an electrode formed on the other surface through the resin layer with a conductive adhesive. Ultrasonic probe. The ultrasonic probe according to any one of claims 1 to 6, wherein ultrasonic waves are transmitted to and received from a subject;
Transmitting / receiving means for driving the ultrasonic probe to scan the inside of the subject;
Image processing means for generating an image of the subject based on a received signal obtained by scanning of the transmitting / receiving means;
Display means for displaying the image generated by the image processing means;
An ultrasonic diagnostic apparatus comprising:

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