Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
  • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
  • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
  • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
  • B06B1/0207—Driving circuits
• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
  • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
  • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
  • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
  • B06B1/0292—Electrostatic transducers, e.g. electret-type

Definitions

• the present invention relates to an integrated circuit arrangement for an ultrasound transducer array.
• the present invention relates to an integrated circuit arrangement that comprises a set of capacitive micromachined ultrasound transducers (CMUT).
• CMUT capacitive micromachined ultrasound transducers
• the present invention further relates to an ultrasound transducer comprising such an integrated circuit as well as to an ultrasound imaging system with this ultrasound transducer.
• CMUT capacitive micromachined ultrasound transducers
• CMUTs are being investigated for use in medical diagnostic and therapeutic ultrasound.
• ASIC application-specific integrated circuitry
• CMUTs complementary metal-oxide-semiconductor
• Devices have been fabricated with square as well as hexagonal patterns of CMUTs, in which the CMUTs themselves are circular or hexagonal. From the point of view of optimal filling of area with CMUTs, the hexagonal pattern is the most efficient. Typical cell dimensions of such hexagonal CMUT cells are 25-50 microns from flat edge to flat edge on the hexagon.
• the therein provided integrated circuit comprises a substrate comprising a hexagonal arrangement of CMOS cells, wherein every other column of said CMOS cells is offset from adjoining columns by a distance equal to one -half of the cell dimension in said column direction, and the width of each cell is selected such that the CMOS cells line up with respective micromachined elements.
• a hexagonal arrangement of CMUT cells overlays the substrate, wherein the CMUT and the CMOS cells are arranged in a one-to-one
• an integrated circuit arrangement comprising:
• CMUT capacitive micromachined ultrasound transducer
• an ultrasound transducer that comprises such an integrated circuit arrangement.
• Separately handling the beamforming of even and odd columns furthermore has the advantage that standard components may be used for providing the beamforming delays to the even columns, and also standard components can be used for providing the beamforming delays to the odd columns.
• This extremely simplifies the fabrication and therefore saves production costs. Apart from that, it allows to save space on the ASIC which is left over for the CMUT and the TR cells. This again means that image resolution can be improved. In other words, area utilization of the surface is maximized for CMUT coverage.
• the first hardware unit comprises a first set of buses
• the second hardware unit comprises a second set of buses.
• the delay functions used for microbeamforming are communicated on two separate sets of buses which run horizontally, i.e. transverse or perpendicular to the column direction, across the ASIC.
• the first set of buses is used to control the TR cells of the even numbered columns
• the second set of buses is used to control the TR cells of the odd numbered columns.
• CMUT cells are laid out on top of the rectangular array of microbeamformer TR cells.
• a dimension of the TR cells in the column direction is smaller than the dimension of a CMUT cell in the column direction (vertical direction).
• the first and the second set of buses each comprise several horizontal bus lines which are arranged in the gaps between the parallel TR cell rows running transverse to the column direction. Using these gaps for the arrangement of the horizontal bus lines is a very intelligent solution, since these bus lines do then not interfere with the TR cells, while there is still enough room for the TR cells themselves.
• Fig. 1 shows a schematic illustration of an embodiment of an ultrasound imaging system
• Fig. 2b shows an example of a schematic detailed view on a transducer array and a beamformer
• Figs. 3a and 3b schematically show a hexagonal arrangement of CMUT cells with an efficient ASIC layout that is suitable for a microbeamformer according to an embodiment of the present invention
• Fig. 4 schematically illustrates a cross-section of a CMUT cell to illustrate the principle design and function of such a CMUT cell.
• the input device 20 may have buttons, a key pad and/or a touchscreen to provide an input mechanism to a user of the ultrasound imaging system 10. Additionally or alternatively, other mechanisms may be present in the input device 20 to enable a user to control the ultrasound imaging system 10.
• sub-arrays 38, 38' For illustrative purposes, merely two sub-arrays 38, 38' are shown in Fig. 2b. However, the number of sub-arrays 38, 38' may also be greater than 2, e.g. 8, 16, 32, 64, 128, etc.
• acoustic pulses are generated from the transducer elements 36 of the transducer array 26.
• echoes from those pulses in the volume 24 are received by the acoustic elements of the transducer array 26, amplified and combined.
• transmit delay pulsers generate delayed high voltage pulses.
• the acoustic pulses are transmitted by the transducer elements 36.
• the acoustic pulses are timed relative to each other to generate a focus in the three-dimensional space of the insonified medium.
• the acoustic pulses previously transmitted are echoed by structures in the volume 24.
• the CMUT cell 40 is preferably fabricated on a substrate 50 which may comprise heavily doped silicone.
• the electrodes 46, 48 are preferably made of a conductive material, such as a metal alloy.
• the cavity 44 is preferably evacuated. However, it may also be filled with any suitable gas. It shall be understood that the CMUT cells used in the integrated circuit arrangement according to the present invention may differ in its design from the CMUT cell 40 that is schematically shown in Fig. 4. Fig. 4 is herein only used for illustrative purposes and to explain the general working principle of such a CMUT cell.
• the hexagonal pattern is the most efficient.
• the hexagonal arrangement furthermore has the advantage that the effective acoustic pitch in the x+30° and the y-direction is reduced below the inherent hexagonal pitch spacing of the CMUTs 40 and below the y-pitch of the TR cells 54. This increases the frequency at which grating lopes become a significant source of artifacts for a given steering angle.
• CMUT cells 40 due to the hexagonal arrangement of the CMUT cells 40, they appear to be arranged in different straight columns 56, 56', wherein CMUT cells in one column 56, 56' are all aligned with each other. However, as indicated in the upper part of Fig. 3b, CMUT cells 40 of adjacent columns 56, 56' are arranged offset to each other by one-half the vertical pitch of a hexagonal CMUT cell 40. This offset is indicated in Fig. 3b by d, wherein:
• the hexagonal array of CMUT cells 40 comprises a plurality of alternating even columns 56 and odd columns 56' being parallel to a column direction y, wherein the odd columns 56' are arranged offset to the even column 56 by d, seen in column direction y.
• the TR cells 54 are preferably arranged in parallel rows running in x- direction (perpendicular to the column direction y), this means that TR cells 54 which are assigned to CMUT cells 40 in odd columns 56' are also arranged slightly offset from them.
• Connection pads 58' that are used to connect the TR cells 54 to the CMUTs 40 are in odd columns 56' therefore slightly larger than in even columns 56 (compare reference numerals 58 and 58').
• this is solved by providing an offset regulator 60 on the ASIC 52 for providing different beamforming delays to even and odd columns 56, 56' of the hexagonal array of CMUT cells 40 in order to account for the offset d.
• the geometrical offset between alternate columns 56, 56' is thereby preferably eliminated by a hardware-implemented solution.
• the presented beamforming control aggregates the even and odd columns 56, 56', meaning that even and odd columns 56, 56' are preferably controlled separately.
• this is realized by providing two copies of the hardware which is responsible for providing the vertical dependent delay functions to the TR cells 54. These functions are communicated on two separate sets of buses 62, 64.
• the beamforming delays provided by the first set of buses 62 and the beamforming delays provided by the second set of buses 64 may, however, be implemented to differ in a time-constant delay function that depends on the offset d between even and odd columns 56, 56' in the column direction y. Since this static difference is thereby already accounted for, the two separate sets of buses 62, 64 may control the delays as if the CMUT cells 40 were realized as rectangular or quadratic cells in an evenly distributed array without geometrical offsets between alternate columns or rows. This extremely facilitates the microbeamforming control of the system.
• the vertical dimensions in y- direction of the TR cells 44 are preferably chosen to be smaller than the respective dimensions in vertical direction y of the CMUT cells 40. Therefore, a small space is left between adjacent rows of TR cells 54. This extra space can be used to place the horizontal bus lines of the first and second set of buses 62, 64 on the ASIC 52.
• the present invention provides an intelligent combination of a hexagonal pattern of CMUTs with an efficient ASIC layout suitable for microbeamforming.
• the intelligent design of the provided integrated circuit arrangement allows easy and efficient micro beamforming with such a hexagonal array of CMUT cells. Due to the separate consideration of even and odd columns within the hexagonal cell array the micro
• beamforming technique accounts for the vertical offset of alternating columns of sensors in an easy and cost-efficient way.

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• Engineering & Computer Science (AREA)
• Health & Medical Sciences (AREA)
• Mechanical Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Biomedical Technology (AREA)
• Molecular Biology (AREA)
• Biophysics (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Pathology (AREA)
• Radiology & Medical Imaging (AREA)
• Gynecology & Obstetrics (AREA)
• Heart & Thoracic Surgery (AREA)
• Medical Informatics (AREA)
• Physics & Mathematics (AREA)
• Surgery (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Ultra Sonic Daignosis Equipment (AREA)
• Transducers For Ultrasonic Waves (AREA)
• Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)

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• 2014
  • 2014-06-24 WO PCT/IB2014/062559 patent/WO2014207654A2/en not_active Ceased
  • 2014-06-24 CN CN201480036530.XA patent/CN105339097B/zh active Active
  • 2014-06-24 JP JP2016522924A patent/JP6279725B2/ja active Active
  • 2014-06-24 US US14/898,844 patent/US10828671B2/en active Active
  • 2014-06-24 EP EP14741395.9A patent/EP3013486B1/en active Active

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