Patent Publication Number: US-2010125208-A1

Title: Probe For Ultrasound System And Method Of Manufacturing The Same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims the benefit of Korean Patent Application No. 10-2008-0115410 filed on Nov. 19, 2008, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a probe and, more particularly, to a probe for an ultrasound system that generates internal images of a patient body with ultrasound waves, and a method of manufacturing the same. 
     2. Description of the Related Art 
     Generally, an ultrasound system refers to a non-invasive apparatus that irradiates an ultrasound signal from a surface of a patient body towards a target internal organ beneath the body surface and obtains an image of a monolayer or blood flow in soft tissue from information in the reflected ultrasound signal (ultrasound echo-signal). The ultrasound system has been widely used for diagnosis of the heart, the abdomen, the urinary organs, and in obstetrics and gynecology due to various merits such as small size, low price, real-time image display, and high stability through elimination of any radiation exposure, as compared with other image diagnostic systems, such as X-ray diagnostic systems, computerized tomography scanners (CT scanners), magnetic resonance imagers (MRIs), nuclear medicine diagnostic apparatuses, and the like. 
     Particularly, the ultrasound system includes a probe which transmits an ultrasound signal to a patient body and receives the ultrasound echo-signal reflected therefrom to obtain the ultrasound image of the patient body. 
     The probe includes a transducer, a case with an open upper end, a cover coupled to the open upper end of the case to directly contact the body surface of the patient, and the like. 
     The transducer includes a piezoelectric layer in which a piezoelectric material converts electrical signals into sound signals or vice versa while vibrating, a coordination layer reducing a difference in sound impedance between the piezoelectric layer and a patient body to allow as much of the ultrasound waves generated from the piezoelectric layer to be transferred to the patient body as possible, a lens layer focusing the ultrasound waves, which travel in front of the piezoelectric layer, onto a predetermined point, and a backing layer blocking the ultrasound waves from traveling in a rearward direction of the piezoelectric layer to prevent image distortion. 
     The piezoelectric layer includes a piezoelectric member and electrodes provided to upper and lower ends of the piezoelectric member, respectively. Further, a printed circuit board (PCB) is bonded to the piezoelectric layer. The PCB is joined to the piezoelectric member by soldering with a solder such as lead or the like. 
     Here, since soldering between the piezoelectric member and the PCB is a difficult and laborious operation entailing heat generation, not only does the probe require a long manufacturing time, but also is likely to undergo deterioration in performance of the piezoelectric member resulting from the heat generated during the soldering operation. Moreover, since the soldering is carried out by a manual operation, a soldered portion has a low durability and uniformity, causing deterioration in performance of the probe. Therefore, there is a need for an improved probe that overcomes such problems. 
     SUMMARY OF THE INVENTION 
     The present invention is conceived to solve the problems of the conventional technique as described above, and an aspect of the present invention is to provide an improved probe for an ultrasound system, which permits easy manufacture while preventing performance deterioration resulting from heat generation or defective connection between a piezoelectric member and a PCB during manufacturing, and a method of manufacturing the same. 
     In accordance with an aspect of the present invention, a probe for an ultrasound system includes a backing layer; a piezoelectric member installed to the backing layer; and a unidirectional conduction part installed to at least one of the backing layer and the piezoelectric member. 
     The piezoelectric member may be formed with first and second electrodes, the unidirectional conduction part being installed to the first and second electrodes. 
     The piezoelectric member may include a plurality of piezoelectric members arranged side by side, the unidirectional conduction part being installed to the plurality of piezoelectric members. 
     The unidirectional conduction part may include an anisotropic conduction material. 
     The probe may further include a printed circuit board (PCB) installed to the unidirectional conduction part. 
     In accordance with another aspect of the present invention, there is provided a method of manufacturing a probe for an ultrasound system, including: installing a piezoelectric member having first and second electrodes to a backing layer; and installing a unidirectional conduction part to the first and second electrodes. 
     The step of installing a piezoelectric member may include installing a plurality of piezoelectric members. 
     The step of installing a unidirectional conduction part may include installing the unidirectional conduction part to the plurality of piezoelectric members. 
     The method may further include installing a printed circuit board (PCB) to the unidirectional conduction part. 
     According to the embodiment of the present invention, the probe is manufactured by connecting the piezoelectric member to the PCB via the unidirectional conduction part, instead of soldering which requires difficult and laborious operations, thereby facilitating manufacture of the probe while reducing an operation time in manufacture of the probe. 
     Further, the first and second electrodes, which are separated from other first and second electrodes so as to form each channel, are firmly and uniformly connected to line electrodes of the PCB via the unidirectional conduction part in a single heating and pressing operation instead of the laborious soldering operation, thereby preventing performance deterioration or malfunction of the probe resulting from low durability and non-uniformity of a connected part. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features and advantages of the present invention will become apparent from the following description of exemplary embodiments given in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a perspective view of a probe for an ultrasound system according to an embodiment of the present invention; 
         FIG. 2  is a flowchart of a method of manufacturing a probe for an ultrasound system according to an embodiment of the present invention; and 
         FIGS. 3 to 5  are views illustrating a process of installing a PCB to a piezoelectric member. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT 
     Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the drawings are not to precise scale and may be exaggerated in thickness of lines or size of components for descriptive convenience and clarity only. Furthermore, terms used herein are defined by taking functions of the present invention into account and can be changed according to the custom or intention of users or operators. Therefore, definition of the terms should be made according to overall disclosures set forth herein. 
     Referring to  FIG. 1 , which is a perspective view of a probe  100  for an ultrasound system according to an embodiment of the present invention, the probe  100  includes a backing layer  110  and a piezoelectric member  120 . 
     The backing layer  110  is disposed at the rear of the piezoelectric member  120 . The backing layer  110  reduces a pulse width of an ultrasound wave by suppressing free vibration of the piezoelectric member  120 , and prevents image distortion by blocking unnecessary propagation of the ultrasound wave in the rearward direction of the piezoelectric member  120 . The backing layer  110  can be formed of a material containing a rubber to which epoxy, tungsten powder, and the like are added. 
     The piezoelectric member  120  is “installed” to the backing layer  110 . The piezoelectric member  120  generates ultrasound waves using a resonance phenomenon. The piezoelectric member  120  may be formed of a ceramic of lead zirconate titanate (PZT), a PZNT single crystal made of a solid solution of lead zinc niobate and lead titanate, a PZMT single crystal made of a solid solution of lead magnesium niobate and lead titanate, or the like. 
     The piezoelectric member  120  is formed with first and second electrodes  122  and  124 . The first and second electrodes  122  and  124  are disposed to surround the piezoelectric member  120 . The first and second electrodes  122  and  124  may be formed of a highly conductive metal such as gold, silver or copper. Here, one of the first and second electrodes  122  and  124  serves as a positive pole of the piezoelectric member  120 , and the other serves as a negative pole of the piezoelectric member  120 . The first and second electrodes  122  and  124  are separated from each other to allow the positive pole and the negative pole to be separated from each other. In this embodiment, the first and second electrodes  122  and  124  are illustrated as serving as the positive and negative poles, respectively. 
     Further, the first and second electrodes  122  and  124  are configured to be disposed symmetrically to each other, thereby making upper and lower portions of the piezoelectric member  120  symmetrical to each other. Herein, each of the first and second electrodes  122  and  124  may have a “J”-shape that surrounds the piezoelectric member  120 . With the first and second electrodes  122  and  124  disposed on the piezoelectric member  120 , the upper and lower portions of the piezoelectric member  120  are symmetrical to each other, so that there is no need for differentiating the upper and lower portions of the piezoelectric member  120 , thereby allowing the piezoelectric member  120  to be installed to the backing layer  110  without differentiating the upper and lower portions thereof. 
     An array of piezoelectric members  120  with the configuration described above are arranged to form multiple channels. According to this embodiment, the piezoelectric member  120  is divided into the plural piezoelectric members  120  separated a predetermined distance from each other on a single backing layer  110  by dicing, and the plural piezoelectric members  120  are arranged side by side to constitute the array of piezoelectric members  120 . However, the present invention is not limited to this configuration. Alternatively, both the piezoelectric member  120  and the backing layer  110  may be divided into plural piezoelectric members  120  and plural backing layers  110  separated a predetermined distance from each other by dicing, such that plural laminates of the backing layers  110  and the piezoelectric members  120  may be disposed side by side in an array. 
     The probe  100  for an ultrasound system according to this embodiment may further include a unidirectional conduction part  130  and PCBs  140 . 
     The unidirectional conduction part  130  is installed to the piezoelectric members  120  which are disposed in an array as described above. A single unidirectional conduction part  130  comprising an anisotropic conduction material is installed to each side of the first and second electrodes  122  and  124 . 
     The anisotropic conduction material is a bonding material which can accomplish electrical and mechanical coupling between electrodes by application of a predetermined pressure and heat thereto. The anisotropic conduction material has properties dependent on the application direction of pressure, so that only a part of the anisotropic conduction material exposed to pressure exhibits electrical conductivity, but other parts thereof free from the pressure do not exhibit the electrical conductivity. Thus, the unidirectional conduction part  130  comprising the anisotropic conduction material allows separation of electrodes between channels in a single mechanical process. 
     The PCBs  140  are installed to the unidirectional conduction part  130 . The PCBs  140  are disposed substantially perpendicular with respect to the direction in which the backing layer  110  and the piezoelectric member  120  are laminated. The PCB  140  includes a flexible printed circuit board (FPCB), and any other configurations capable of supplying signals or electricity. 
     According to this embodiment, the PCB  140  having a plurality of line electrodes (not shown) formed thereon is installed to each side of the first and second electrodes  122  and  124 . The PCBs  140  are connected to the piezoelectric members  120  via the unidirectional conduction part  130 . 
     Herein, the term “installing” or “installed” means that two or more components are electrically connected to each other through interconnection therebetween. Hence, the PCBs  140  are electrically connected to the piezoelectric members  120  through interconnection therewith, so that the PCBs  140  can be installed to the piezoelectric members  120 . 
     In other words, when the PCBs  140  are compressed at a predetermined pressure and heat with the unidirectional conduction part  130  interposed therebetween, each of the PCBs  140  is mechanically coupled to the piezoelectric members  120  via the unidirectional conduction part  130  while plural line electrodes of the PCBs  140  are electrically connected to the first and second electrodes  122  and  124  of the piezoelectric members  120 . A detailed description of this configuration will be described below. 
     Reference numerals  150  and  160  indicate a coordination layer of a glass or resin material for reducing a difference in sound impedance between a patient body and the probe, and a lens layer for focusing ultrasound waves traveling in front of the piezoelectric member  120  onto a particular point, respectively. 
       FIG. 2  is a flowchart of a method of manufacturing a probe for an ultrasound system according to an embodiment of the present invention, and  FIGS. 3 to 5  are views illustrating a process of installing a PCB to a piezoelectric member. 
     Referring to  FIGS. 2 to 5 , a method of manufacturing a probe for an ultrasound system according to an embodiment of the present invention will now be described. 
     To manufacture a probe  100  for an ultrasound system according to the embodiment of the invention, first, a backing layer  110  is formed using a material including a rubber, to which epoxy resin or tungsten powder is added, and a piezoelectric member  120  having first and second electrodes  122  and  124  is installed to the backing layer  110  in S 10 . 
     Here, the first and second electrodes  122  and  124  are formed symmetrically to each other in a “J”-shape surrounding the piezoelectric member  120 , so that the upper and lower portions of the piezoelectric member  120  become symmetrical to each other to thereby eliminate a need for differentiating the upper and lower portions of the piezoelectric member  120 . Accordingly, the piezoelectric member  120  can be installed to the backing layer  110  without differentiating the upper and lower portions of the piezoelectric member  120 , thereby allowing easy manufacture of the probe  100 . 
     The piezoelectric member  120  is divided into a plurality of piezoelectric members  120  separated a predetermined distance from each other to constitute an array of piezoelectric members  120  arranged side by side, so that the array of piezoelectric members  120  can be used as multiple channels corresponding to a plurality of line electrodes formed on a PCB  140 . 
     A unit of the separated piezoelectric member  120  constitutes a single channel. Thus, such units of the piezoelectric members  120  are arranged side by side in an array, thereby constituting multiple channels. 
     According to this embodiment, a laminate of the backing layer  110  and the piezoelectric member  120  is diced by a dicing apparatus. Dicing is performed to a sufficient depth to allow each of the first and second electrodes  122  and  124  to be reliably divided into plural electrodes. 
     By dicing, the piezoelectric member  120  is divided into the plural piezoelectric members  120  separated a predetermined distance from each other such that the first electrode  122  and the second electrode  124  formed on a single separated piezoelectric member  120  can be completely electrically separated from the first electrode  122  and the second electrode  124  on another adjacent piezoelectric member  120 . 
     According to this embodiment, only the piezoelectric member  120  is illustrated as being divided by dicing to constitute the array of piezoelectric members  120  arranged side by side on the single backing layer  110 . However, it should be noted that the present invention is not limited to this configuration. Alternatively, the backing layer  110  may also be divided along with the piezoelectric member  120  by dicing to divide the laminate of the backing layer  110  and the piezoelectric member  120  into plural laminates of the backing layers and the piezoelectric members such that an array of separated laminates arranged side by side can be constituted. 
     After the piezoelectric members  120  are installed to the backing layer  110 , in S 20 , a unidirectional conduction part  130  comprising an anisotropic material is installed to the plural first and second electrodes  122  and  124 , which are arranged side by side in an array, and PCBs  140  are installed to the unidirectional conduction part  130  disposed on the first and second electrodes  122  and  124  in S 30 , as shown in  FIGS. 4 and 5 . At this time, the unidirectional conduction part  130  and PCBs  140  are provided substantially perpendicular with respect to the direction of laminating the backing layer  110  and the piezoelectric members  120 . 
     The anisotropic conduction material is a bonding material which can accomplish electrical and mechanical coupling between electrodes by application of predetermined pressure and heat thereto. The anisotropic conduction material contains conductive particles in a predetermined density to provide anisotropic conductivity. That is, the conductive particles of the anisotropic conduction material become nonconductive when pressure is not applied thereto. However, when pressure is applied thereto, the conductive particles of the anisotropic conduction material are brought into contact with each other and exhibit conductivity only in the direction in which pressure is applied. 
     Therefore, when a predetermined pressure and heat are applied to the unidirectional conduction part  130  via the PCBs  140  with the unidirectional conduction part  130  interposed between the PCBs  140  and the plural piezoelectric members  120  arranged side by side, and with the PCBs  140  aligned to allow the respective first and second electrodes  122  and  124  to be connected to the associated line electrodes of the PCBs  140 , the PCBs  140  per se are bonded to the piezoelectric members  120  via the unidirectional conduction part  130 , and the line electrodes of the PCBs  140  are electrically connected to the first and second electrodes  122  and  124  via the unidirectional conduction part  130 , respectively. 
     At this time, the pressure applied to the unidirectional conduction part  130  acts on connected parts between the first and second electrodes  122  and  124  and the line electrodes, so that the piezoelectric members  120  and the line electrodes of the PCBs  140  are connected to each other to provide conductivity only in each channel. 
     Although the method of manufacturing the probe has been illustrated as performing the operation of installing the unidirectional conduction part  130  and the PCBs  140  after the operation of installing the piezoelectric member  120  to the backing layer  110  in this embodiment, the present invention is not limited to this order. In other words, these operations may be performed in a reverse sequence or at the same time. 
     In this embodiment, the unidirectional conduction part  130  is illustrated as being installed to the piezoelectric members  120 , but the present invention is not limited to this configuration. Alternatively, the unidirectional conduction part  130  may be installed to the backing layer  110 , in which electrodes connected to the first and second electrodes  122  and  124  of the piezoelectric members  120  for the respective channels are formed, such that the electrodes of the backing layer  110  can be electrically connected to the PCBs  140  therethrough. 
     In the probe  100  for an ultrasound system according to the embodiment of the invention as described above, the piezoelectric members  120  are electrically connected to the PCBs  140  by electrically connecting the first and second electrodes  122  and  124  to the line electrodes of the PCBs  140  via the unidirectional conduction part  130 , thereby providing the following advantageous effects. 
     First, in manufacture of the probe  100 , the piezoelectric members  120  and the PCBs  140  are connected to each other via the unidirectional conduction part  130  instead of soldering which requires difficult and laborious operations, thereby facilitating manufacture of the probe while reducing an operation time in manufacture of the probe. 
     Secondly, the first and second electrodes  122  and  124 , which are separated from other first and second electrodes so as to form each channel, are firmly and uniformly connected to the line electrodes of the PCBs  140  via the unidirectional conduction part  130  in a single heating and pressing operation instead of the laborious soldering, thereby preventing performance deterioration or malfunction of the probe resulting from low durability and non-uniformity of connection therebetween. 
     Although the present invention has been described with reference to the embodiments shown in the drawings, it will be apparent to those skilled in the art that the embodiments are given by way of illustration only, and that various modifications and equivalent embodiments can be made without departing from the spirit and scope of the present invention. Accordingly, the scope of the present invention should be limited only by the accompanying claims.