Ultrasonic Fingerprint Sensor With Transmit Beamforming Based On A Pmut Array Bonded To Cmos Circuitry

• doi: 10.1109/TUFFC.2017.2703606
• title: Ultrasonic Fingerprint Sensor With Transmit Beamforming Based on a PMUT Array Bonded to CMOS Circuitry
• publisher: IEEE
• isbn:
• issn: 1525-8955
• rank: 3930
• access_type: LOCKED
• content_type: Journals
• abstract: In this paper, we present a single-chip 65 × 42 element ultrasonic pulse-echo fingerprint sensor with transmit (TX) beamforming based on piezoelectric micromachined ultrasonic transducers directly bonded to a CMOS readout application-specific integrated circuit (ASIC). The readout ASIC was realized in a standard 180-nm CMOS process with a 24-V high-voltage transistor option. Pulse-echo measurements are performed column-by-column in sequence using either one column or five columns to TX the ultrasonic pulse at 20 MHz. TX beamforming is used to focus the ultrasonic beam at the imaging plane where the finger is located, increasing the ultrasonic pressure and narrowing the 3-dB beamwidth to 50 μm, a factor of 6.4 narrower than nonbeamformed measurements. The surface of the sensor is coated with a poly-dimethylsiloxane (PDMS) layer to provide good acoustic impedance matching to skin. Scanning laser Doppler vibrometry of the PDMS surface was used to map the ultrasonic pressure field at the imaging surface, demonstrating the expected increase in pressure, and reduction in beamwidth. Imaging experiments were conducted using both PDMS phantoms and real fingerprints. The average image contrast is increased by a factor of 1.5 when beamforming is used.
• article_number: 7926420
• pdf_url: https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=7926420
• html_url: https://ieeexplore.ieee.org/document/7926420/
• abstract_url: https://ieeexplore.ieee.org/document/7926420/
• publication_title: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
• conference_location:
• conference_dates:
• publication_number: 58
• is_number: 8017665
• publication_year: 2017
• publication_date: Sept. 2017
• start_page: 1401
• end_page: 1408
• citing_paper_count: 123
• citing_patent_count: 0
• download_count: 5429
• insert_date: 20170511
• index_terms:
  • ieee_terms:
    • Fingerprint recognition
    • Acoustics
    • Array signal processing
    • Electrodes
    • Ultrasonic variables measurement
    • Micromechanical devices
    • Aluminum nitride
  • author_terms:
    • Fingerprint sensor
    • imaging
    • microelectromechanical systems (MEMS)
    • micromachining
    • piezoelectric
    • piezoelectric micromachined ultrasonic transducers (PMUT)
    • transducers
    • ultrasonic
    • ultrasound
  • dynamic_index_terms:
    • Ultrasonic Sensors
    • Ultrasonic Detection
    • Fingerprint Sensors
    • Piezoelectric Micromachined Ultrasonic Transducers
    • Increase In Pressure
    • Pressure Field
    • Sensor Surface
    • Acoustic Impedance
    • Polydimethylsiloxane Surface
    • Laser Doppler Vibrometer
    • Laser Vibrometer
    • Laser Doppler Vibrometry
    • Standard CMOS
    • Aperture
    • Image Resolution
    • Ultrasound Imaging
    • Peak Pressure
    • Top Electrode
    • Measurement Cycle
    • Capacitive Sensor
    • Pressure Output
    • Aluminum Nitride
    • Polydimethylsiloxane Layer
    • Central Column
    • Piezoelectric Coefficient
    • High Fill Factor
    • Adjacent Columns
    • Column Array
    • Acoustic Field
• authors:
  • Author Name: Xiaoyue Jiang
    Affiliation: Department of Mechanical Engineering, University of California at Berkeley, Berkeley, CA, USA
    Author URL: https://ieeexplore.ieee.org/author/37085699649
    ID: 37085699649
    Order: 1
    Author Affiliations:
    • Department of Mechanical Engineering, University of California at Berkeley, Berkeley, CA, USA
  • Author Name: Hao-Yen Tang
    Affiliation: Department of Electrical Engineering and Computer Science, University of California at Berkeley, Berkeley, CA, USA
    Author URL: https://ieeexplore.ieee.org/author/37085442217
    ID: 37085442217
    Order: 2
    Author Affiliations:
    • Department of Electrical Engineering and Computer Science, University of California at Berkeley, Berkeley, CA, USA
  • Author Name: Yipeng Lu
    Affiliation: Qualcomm Inc., Santa Clara, CA, USA
    Author URL: https://ieeexplore.ieee.org/author/37085445079
    ID: 37085445079
    Order: 3
    Author Affiliations:
    • Qualcomm Inc., Santa Clara, CA, USA
    • Department of Mechanical and Aerospace Engineering, University of California at Davis, Davis, CA, USA
  • Author Name: Eldwin J. Ng
    Affiliation: InvenSense Inc., San Jose, CA, USA
    Author URL: https://ieeexplore.ieee.org/author/37711201400
    ID: 37711201400
    Order: 4
    Author Affiliations:
    • InvenSense Inc., San Jose, CA, USA
  • Author Name: Julius M. Tsai
    Affiliation: InvenSense Inc., San Jose, CA, USA
    Author URL: https://ieeexplore.ieee.org/author/37085530599
    ID: 37085530599
    Order: 5
    Author Affiliations:
    • InvenSense Inc., San Jose, CA, USA
    • NextInput Inc., San Jose, CA, USA
  • Author Name: Bernhard E. Boser
    Affiliation: Department of Mechanical Engineering, University of California at Berkeley, Berkeley, CA, USA
    Author URL: https://ieeexplore.ieee.org/author/37282431400
    ID: 37282431400
    Order: 6
    Author Affiliations:
    • Department of Mechanical Engineering, University of California at Berkeley, Berkeley, CA, USA
  • Author Name: David A. Horsley
    Affiliation: Department of Mechanical and Aerospace Engineering, University of California at Davis, Davis, CA, USA
    Author URL: https://ieeexplore.ieee.org/author/37372231100
    ID: 37372231100
    Order: 7
    Author Affiliations:
    • Department of Mechanical and Aerospace Engineering, University of California at Davis, Davis, CA, USA

Image Sensor

• sensor_type: PMUT (Piezoelectric Micromachined Ultrasonic Transducers)
• resolution: 65 × 42
• dynamic_range: Not explicitly mentioned
• pixel_size: 35 µm diameter
• dark_current: Not mentioned

Optical Data

• focal_length: Not mentioned
• aperture: Not mentioned
• field_of_view: Not mentioned
• distortion: Not mentioned

Performance Metrics

• frame_rate: Not mentioned
• signal_to_noise_ratio: 7 dB increase with TX beamforming
• sensitivity: Not mentioned
• shutter_speed: Not specified, but involves pulse-echo measurements
• power_consumption: Not explicitly mentioned in detail,
• noise: Input-referred noise is 46 µV

Applications & Benefits

• cell_imaging: Ultrasonic imaging for fingerprint recognition, particularly effective on wet fingers
• benefits: Improved security for access control and payment systems, high resolution fingerprint images through improved pressure and beamwidth.

Supporting Organizations

• supported_by: University of California, Berkeley; InvenSense Inc.; Qualcomm Inc.; NextInput Inc.

Manuscript Details

• publication_date: Sept. 2017

Relevancy Score

• score: 6
• missing_fields:
  • fill factor
  • quantum efficiency
  • readout speed
  • microlenses
  • on-chip colour filters
  • global or rolling shutters
  • backside illumination

Processed JSON Filename

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