Ultrasonic fingerprint scanning by means of photoacoustic excitation

Patent metadata

Field	Value
Publication number	US-2020410190-A1
Application number	US-201916454550-A
Country	US
Kind code	A1
Filing date	Jun 27, 2019
Priority date	Jun 27, 2019
Publication date	Dec 31, 2020
Grant date	—

Abstract

The described techniques support a sensing scheme for electromagnetic excitation in ultrasonic imaging sensors. A biological tissue may be sensed and imaged using an electromagnetic excitation process to generate ultrasonic waves, such as, within the tissue. A component of a device may generate one or more pulses of electromagnetic waves, which may encounter and enter the biological tissue. In some examples, the component may be a display interface or may be different from a display interface of the device. The electromagnetic waves may excite the biological tissue and generate ultrasonic waves via expansion and contraction of the tissue upon heating. The ultrasonic waves may propagate within the biological tissue and may be sensed by an ultrasonic receiver array. The sensed ultrasonic waves may be converted to pixel image data of a biometric image and may be used for biometric authentication.

First claim

1 . A method of biometric imaging at a device, comprising:
generating, via a light emitting source of the device, one or more pulses of electromagnetic radiation waves, wherein the light emitting source is separate from a display interface of the device; selecting one or more wavelengths of the one or more pulses of electromagnetic radiation waves based at least in part on a target depth level associated with the one or more biological tissues of a finger to stimulate the one or more biological tissues of the finger to generate the one or more ultrasonic signals; emitting, via the light emitting source, the one or more pulses of electromagnetic radiation waves, to generate one or more ultrasonic signals associated with one or more biological tissues of the finger, based at least in part on the one or more wavelengths; sensing, via an ultrasonic receiver array of the device, the one or more generated ultrasonic signals based at least in part on emitting the one or more pulses of electromagnetic radiation waves; generating a fingerprint image comprising at least one of ridges or valleys associated with the finger based at least in part on the sensing; and outputting a representation of the fingerprint image.

2 . The method of claim 1 , wherein emitting, via the light emitting source of the device, the one or more pulses of electromagnetic radiation waves comprises:
emitting the one or more pulses of electromagnetic radiation waves from the light emitting source of the device that is external to a footprint of the display interface.

3 . The method of claim 1 , wherein emitting, via the light emitting source of the device, the one or more pulses of electromagnetic radiation waves comprises:
emitting the one or more pulses of electromagnetic radiation waves from the light emitting source that is external to a footprint of the device.

4 . The method of claim 1 , wherein sensing, via the ultrasonic receiver array of the device, the one or more generated ultrasonic signals comprises:
sensing, via the ultrasonic receiver array of the device, the one or more generated ultrasonic signals across one or more of an axial plane, a coronal plane, or a sagittal plane associated with the finger, wherein the fingerprint image comprises a tomographic fingerprint image based at least in part on sensing the one or more generated ultrasonic signals across one or more of the axial plane, the coronal plane, or the sagittal plane associated with the finger.

5 . The method of claim 1 , wherein sensing, via the ultrasonic receiver array of the device, the one or more generated ultrasonic signals comprises:
sensing, via a piezoelectric micromachined ultrasonic transducer (PMUT) of the device, the one or more generated ultrasonic signals.

6 . The method of claim 1 , wherein sensing, via the ultrasonic receiver array of the device, the one or more generated ultrasonic signals comprises:
sensing, via a capacitive micromachined ultrasonic transducer (CMUT) of the device, the one or more generated ultrasonic signals.

7 . The method of claim 1 , wherein the ultrasonic receiver array of the device comprises an array of pixel elements, and wherein sensing, via the ultrasonic receiver array of the device, the one or more generated ultrasonic signals comprises:
converting the one or more generated ultrasonic signals to one or more pixels based at least in part on one or more pixel elements of the array of pixels elements, wherein generating the fingerprint image is further based at least in part on the converting.

8 . (canceled)

9 . The method of claim 8 , wherein the one or more wavelengths are within one or more of a radio spectrum of an electromagnetic spectrum (EM) spectrum, a microwave spectrum of the EM spectrum, a near-infrared spectrum of the EM spectrum, an infrared spectrum of the EM spectrum, a visible spectrum of the EM spectrum, or an ultraviolet spectrum of the EM spectrum.

10 . The method of claim 1 , wherein:
the ridges associated with the finger reflect the one or more generated ultrasonic signals; and the valleys associated with the finger absorb or alter the one or more generated ultrasonic signals.

11 . The method of claim 1 , wherein outputting the representation of the fingerprint image comprises:
outputting, via the display interface of the device, the representation of the fingerprint image, wherein the display interface comprises an organic light emitting diode (OLED) display interface.

12 . The method of claim 1 , wherein the light emitting source comprises one or more of a light emitting diode (LED), a laser, or an organic light emitting diode (OLED) display interface.

13 . The method of claim 1 , wherein the one or more ultrasonic signals are generated by the one or more biological tissues within the finger based at least in part on the one or more pulses of electromagnetic radiation waves.

14 . An apparatus for biometric imaging, comprising:
a processor, memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to:
generate, via a light emitting source of the apparatus, one or more pulses of electromagnetic radiation waves, wherein the light emitting source is separate from a display interface of the apparatus;
select one or more wavelengths of the one or more pulses of electromagnetic radiation waves based at least in part on a target depth level associated with the one or more biological tissues of a finger to stimulate the one or more biological tissues of the finger to generate the one or more ultrasonic signals;
emit, via the light emitting source, the one or more pulses of electromagnetic radiation waves, to generate one or more ultrasonic signals associated with one or more biological tissues of the finger, based at least in part on the one or more wavelengths;
sense, via an ultrasonic receiver array of the apparatus, the one or more generated ultrasonic signals based at least in part on emitting the one or more pulses of electromagnetic radiation waves;
generate a fingerprint image comprising at least one of ridges or valleys associated with the finger based at least in part on the sensing; and
output a representation of the fingerprint image.

15 . The apparatus of claim 14 , wherein the instructions to emitting, via the light emitting source of the apparatus, the one or more pulses of electromagnetic radiation waves are executable by the processor to cause the apparatus to:
emit the one or more pulses of electromagnetic radiation waves from the light emitting source of the apparatus that is external to a footprint of the display interface.

16 . The apparatus of claim 14 , wherein the instructions to emitting, via the light emitting source of the apparatus, the one or more pulses of electromagnetic radiation waves are executable by the processor to cause the apparatus to:
emit the one or more pulses of electromagnetic radiation waves from the light emitting source that is external to a footprint of the apparatus.

17 . The apparatus of claim 14 , wherein the instructions to sensing, via the ultrasonic receiver array of the apparatus, the one or more generated ultrasonic signals are executable by the processor to cause the apparatus to:
sense, via the ultrasonic receiver array of the apparatus, the one or more generated ultrasonic signals across one or more of an axial plane, a coronal plane, or a sagittal plane associated with the finger, wherein the fingerprint image comprises a tomographic fingerprint image based at least in part on sensing the one or

Assignees

• Qualcomm Inc

Inventors

• Kitchens Jack Conway
• Schneider John Keith
• Gojevic Stephen Michael
• Breloff Evan Michael
• Brooks Emily Kathryn
• Stoianov Alexei
• John Archibald Fitzgerald
• Miranto James Anthony

Classifications

• G06V40/1306

  non-optical, e.g. ultrasonic or capacitive sensing · CPC title

• G06F21/32 Primary

  using biometric data, e.g. fingerprints, iris scans or voiceprints · CPC title

• G06V10/143

  Sensing or illuminating at different wavelengths · CPC title

• G06V40/1324

  by using geometrical optics, e.g. using prisms (G06V40/1312 takes precedence) · CPC title

• G06V40/1318

  using electro-optical elements or layers, e.g. electroluminescent sensing · CPC title