Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
  • A61B8/12—Diagnosis using ultrasonic, sonic or infrasonic waves in body cavities or body tracts, e.g. by using catheters
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
  • A61B8/44—Constructional features of the ultrasonic, sonic or infrasonic diagnostic device
  • A61B8/4483—Constructional features of the ultrasonic, sonic or infrasonic diagnostic device characterised by features of the ultrasound transducer
  • A61B8/4488—Constructional features of the ultrasonic, sonic or infrasonic diagnostic device characterised by features of the ultrasound transducer the transducer being a phased array
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K1/00—Printed circuits
  • H05K1/18—Printed circuits structurally associated with non-printed electric components
  • H05K1/189—Printed circuits structurally associated with non-printed electric components characterised by the use of a flexible or folded printed circuit
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/40—Forming printed elements for providing electric connections to or between printed circuits
  • H05K3/403—Edge contacts; Windows or holes in the substrate having plural connections on the walls thereof
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
  • H05K2203/04—Soldering or other types of metallurgic bonding
  • H05K2203/049—Wire bonding
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/0011—Working of insulating substrates or insulating layers
  • H05K3/0044—Mechanical working of the substrate, e.g. drilling or punching
  • H05K3/0052—Depaneling, i.e. dividing a panel into circuit boards; Working of the edges of circuit boards
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49002—Electrical device making
  • Y10T29/49117—Conductor or circuit manufacturing
  • Y10T29/49124—On flat or curved insulated base, e.g., printed circuit, etc.
  • Y10T29/49147—Assembling terminal to base
  • Y10T29/49151—Assembling terminal to base by deforming or shaping
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49002—Electrical device making
  • Y10T29/49117—Conductor or circuit manufacturing
  • Y10T29/49124—On flat or curved insulated base, e.g., printed circuit, etc.
  • Y10T29/49155—Manufacturing circuit on or in base
  • Y10T29/49165—Manufacturing circuit on or in base by forming conductive walled aperture in base

Definitions

• Array-based endoscopic ultrasound systems operating at frequencies in the LlOMHz range are used frequently for laparoscopic imaging where they provide fast scarining rates, dynamic focusing and beam steering.
• endoscopic imaging applications requiring higher resolution such as intravascular, intracardiac, transurethral, trans-nasal and transtympamc imaging
• ultrasound arrays have been challenging to manufacture owing the small element size, small element pitch and need to package the finished endoscope into a small enough package to enter the required lumens.
• These applications have, therefore, been served mainly by single element ultrasound endoscopes which, compared to arrays, suffer slower frame rates, a tradeoff between depth of field and lateral resolution and the necessity of having moving parts in the endoscope head which adds bulk and causes unwanted vibrations.
• an ultrasonic array has piezoelectric material and a plurality of electrodes. Each electrode is electrically connected to a respective signal wire, and the pluraUty of signal wires are embedded in a printed circuit board, the board having an angle of greater than about 60 degrees with respect to the array.
• the configuration described above is included in an endoscope.
• the angle can be greater than 70 degrees.
• the angle can be greater than 80 degrees.
• the angle can be approximately 90 degrees.
• the printed circuit board can be a flexible circuit.
• a method of manufacture of any of the above includes creating vias in the printed circuit board and cutting the vias transversely to expose conductive material at the edge of the board.
• the array is then wire bonded to the conductive material, such that the material acts as a wire bonding pad.
• Other implementations are possible, such as generally when the array is electrically connected to the conductive material by thin metal film, conductive epoxy, or the like.
• the cutting can be accomplished by a dicing saw or by similar methods.
• the cutting can be accomplished by a laser.
• an ultrasonic array has piezoelectric material and a plurality of electrodes. Each electrode is correspondingly electrically connected to one of a plurality of signal wires, the wires having an angle of greater than about 60 degrees with respect to the array. In certain implementations, the angle can be greater than 70 degrees. The angle can be greater than 80 degrees. The angle can be approximately 90 degrees.
• a method of manufacture of approximately perpendicular wire bonds includes creating vias in a flexible circuit and cutting the vias transversely to expose conductive material at the edge of the flexible circuit.
• a method of manufacture of electrical connections between an ultrasonic array and a printed circuit board includes creating vias in the board and cutting the vias transversely to expose the conductive material at the edge of the board.
• FIG. 1 shows a partial perspective view of the probe end of a conventional endoscope.
• FIG. 2 shows a sectional view of the probe end of an endoscope of the present invention.
• FIG. 3 shows a partial perspective view of the probe end of an endoscope of the present invention.
• FIG. 4 depicts steps, from top to bottom, in the method of manufacture of the present invention.
• FIG. 5 shows a graph of impedance in ohms at 10 MHz vs array element number for the endoscope of the Example.
• An array with an electrical harness (such as flex or PCB or series of conductors) may be set a defined angle relative to a stack. There maybe no bend required. The volumetric footprint can be minimized as well as the number of components.
• a surface of piezoelectric material 108 is systematically electroded with electrodes 110, such that it defines an array 112 of individual elements that transmit and receive acoustic signals.
• Piezoelectric materials such as lead zirconate titanate (PZT) or lead manganese niobate in solid solution with lead titanate (PMNx-PT(l-x)) are often used.
• kerfs cuts made into the piezoelectric material 108 are made using a saw, laser, reactive ion etching or other methods.
• Each element in the array 112 is electrically connected (generally by way of a wire bonding pad) to a wire 106, which is correspondingly electrically connected on its other end by wire bonding pads 104 on a printed circuit board 100.
• Signal wires (not shown) embedded in the printed circuit board 100 are electrically connected to each pad 104, and send each signal from each element to the distal end of the probe (this is the end which is mechanically manipulated by a clinician).
• the printed circuit board is a flexible (flex) circuit, which packages many of signal wires composed of conductive material by sandwiching them between flexible polymer layers.
• Printed circuit board 100 could also be inflexible, in which the insulating layers may be FR-4 fiberglass.
• a flex circuit 100 is approximately parallel to the surface of the array 112 for a significant distance before bending away from the probe end.
• the smallest dimension possible for such an endoscope is limited by how much of the flex circuit remains at the probe end.
• bonding pads 104 are exposed on both the flex circuit 100 and the array 112, and wires 106 are used to attach array pads and flex circuit pads to each other.
• the manufacturer specifies a minimum bend radius, often on the order of a few millimeters for a multilayer flex circuit such as those used to carry ultrasound array signals.
• This minimum bend radius requires that the flex circuit extend laterally from the ultrasound array for several millimeters before bending back, which greatly increases the cross-sectional area of the device. It is possible, in some embodiments, that no other structures are needed for mechanical support. In some embodiments, attachment may also be made to wires carried in another structure; if such structure is attached so that the wires meet the plane of the array surface, then a minimum bend radius may be required to avoid damaging such wires. Since the minimum size of a lumen into which the endoscope can enter is limited by the endoscope's cross-sectional area it is desirable to reduce the cross- sectional area as much as possible.
• FIGs. 2 and 3 Rather than have a printed circuit board 100 (such as a flex circuit) wire bonded approximately parallel to the surface of an array 112, instead the flex circuits are wire bonded (or otherwise electrically connected) approximately normal to the array surface. In such an arrangement the flex circuit does not bend, and the cross-sectional probe area need only be large enough to accommodate the array elements, bonding pads, and the thickness of the flex circuit at the probe end.
• This arrangement can be used in a variety of applications, including endoscopic high-frequency phased array ultrasound systems, non-endoscopic high-frequency ultrasound phased arrays, and both endoscopic and non-endoscopic phased and linear ultrasound arrays.
• an endoscope of the present invention comprises a 40 MHz, 64-element phased array transducer packaged into a 2.47 mm by 2.42 mm endoscopic form factor, in which the array is a forward looking kerfless design based on PMN-32%PT with an element-to- element pitch of 38 microns.
• the angle of the flex circuit with respect to the array is approximately 90 degrees. In some embodiments, the angle of the flex circuit with respect to the array is between 80 and 90 degrees. In some embodiments, the angle of the flex circuit with respect to the array is between 70 and 90 degrees. In some embodiments, the angle of the flex circuit with respect to the array is between about 60 and 90 degrees. In some embodiments crossing the normal plane, the angle of the flex circuit with respect to the array may exceed 90 degrees.
• Attaching a printed circuit board approximately perpendicular to an array creates a manufacturing challenge because wire bonds between the array and the printed circuit board must connect to the board edge-on.
• flex circuitry is built by attaching together laminar layers, thus bonding pads cannot easily be mounted on the edge of a flex circuit.
• wire bonds are usually made between two parallel surfaces, it is difficult to make connections to bonding pads on the surface of a printed circuit board in this configuration, whether it is flexible or inflexible.
• This method enables wire bonding of signal wires to array elements; electrical connection is also possible using conductive epoxy or thin film metal deposition.
• the method of manufacture includes the following steps (see FIG. 4).
• a set of filled partial vias 126 is formed in the printed circuit board 100 (FIG. 4 top). These vias correspond to the position of the embedded signal wires 128, which are composed of conductive material suitable for electrical connections.
• this procedure is performed twice such that the vias 126 are arranged in two rows through the depth of the printed circuit board 100, with one row through the top two layers and one through the bottom two layers such that they alternate.
• the board is then cut across its width with a dicing saw so as to cut the vias 126 in half near the edge of the board (FIG. 4 middle), exposing conductive material 124 corresponding to each signal wire at the site of the cut 120 (FIG. 4 bottom).
• the array substrate was a 2.4mm by 2.4 mm piece of PMN-32%PT lapped to 47 um thickness.
• An array of 64 electrodes was photolithographically defined on the top surface of this substrate with an electrode width of 27 um and an element-to-element pitch of 37 um.
• Each electrode was fanned out to a bonding pad arranged in two rows on each side of the array (four rows total).
• a 1.2 um layer of aluminum was sputtered onto the back side of the array to define a ground electrode, and a thick layer of conductive epoxy was attached to it to act as an absorbent acoustic backing layer. This epoxy was removed with a dicing saw in order to avoid making the bonding pads piezo electrically active.
• Two 6- layer flex circuit boards were designed to connect to the elements from either side of the array. Each flex circuit had 32 traces terminating at individual copper-filled vias near the end of the board. The flex circuits were cut through the middle of the solid vias using a dicing saw. The two flex circuit boards were epoxied onto opposite sides of the transducer stack such that the diced vias were aligned with the bonding pads fanned out from the array. A jig was then machined to hold the flex + transducer stack upright in front of the wire-bonding tool. 15-micron thick aluminum wire bonds were used to connect the bonding pads on the array to the diced vias within the thickness of the array.
• wirebonds were encapsulated with a thick insulating epoxy consisting of a 30% by volume mixture of Alumina powder and Epotek 301 (Epotek) insulating epoxy.
• a matching layer/lens combination was then epoxied onto the front face of the endoscope.
• Micro- coaxial cables were directly soldered to the flex circuit at the distal end of the probe.

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• 2013
  • 2013-08-09 WO PCT/CA2013/050613 patent/WO2014022938A1/en not_active Ceased
  • 2013-08-09 JP JP2015525701A patent/JP6261581B2/ja active Active
  • 2013-08-09 CN CN201380042291.4A patent/CN104663006B/zh active Active
  • 2013-08-09 US US14/420,452 patent/US10149660B2/en active Active
  • 2013-08-09 EP EP13827230.7A patent/EP2883429B1/en active Active
  • 2013-08-09 CA CA2880652A patent/CA2880652C/en active Active
• 2018
  • 2018-12-03 US US16/207,502 patent/US20190110773A1/en not_active Abandoned

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