Configuration of an ultrasonic fingerprint sensor relative to a display of a device
Various aspects of the present disclosure relate generally to ultrasonic fingerprint sensor. In some aspects, a device may include a flexible display. The device may include an ultrasonic fingerprint sensor that is configured to transmit and receive an ultrasonic signal in an acoustic path through the flexible display. The device may include an acoustics configuration layer that is situated between the display and the ultrasonic fingerprint sensor. The acoustics configuration layer may be configured to optimize a signal strength of the ultrasonic signal based at least in part on a configuration of one or more layers of the flexible display. Numerous other aspects are provided.
1 . A device comprising:
a flexible display;
an ultrasonic fingerprint sensor that is configured to transmit and receive an ultrasonic signal in an acoustic path through the flexible display; and
an acoustics configuration layer that is situated between the flexible display and the ultrasonic fingerprint sensor,
wherein:
the acoustics configuration layer is configured to optimize a signal strength of the ultrasonic signal based at least in part on a configuration of one or more layers of the flexible display,
the acoustics configuration layer is formed from a resonating material that is configured to cause a first alteration of a transmission of the ultrasonic signal and cause a second alteration of a reception of the ultrasonic signal, the second alteration being different from the first alteration, and
a thickness of the resonating material is approximately 10% of the thickness of all layers of the flexible display.
2 . The device of claim 1 , wherein the resonating material includes tin, lead, titanium, stainless steel, copper, or tungsten.
3 . The device of claim 1 , wherein the thickness of the resonating material is less than 50 microns.
4 . The device of claim 1 , wherein an operational frequency range of the ultrasonic signal is between 1 megahertz and 15 megahertz.
5 . The device of claim 1 , wherein a maximum area of the resonating material is at least 25% of a maximum active area of the flexible display.
6 . The device of claim 1 , wherein a thickness of a non-resonating material of the acoustics configuration layer is based at least in part on a half-wavelength of the ultrasonic signal.
7 . The device of claim 6 , wherein the thickness of the non-resonating material is substantially the same as the thickness of all layers of the flexible display.
8 . The device of claim 1 , wherein an operational frequency range of the ultrasonic signal is between 10 megahertz and 20 megahertz.
9 . The device of claim 1 , wherein a non-porous adhesive layer is positioned between the flexible display and the acoustics configuration layer.
10 . The device of claim 9 , wherein the non-porous adhesive layer is laminated to a layer of the flexible display.
11 . The device of claim 1 , wherein the ultrasonic fingerprint sensor is positioned within a recess of a backing layer of the flexible display.
12 . The device of claim 11 , wherein the backing layer comprises at least one of a porous foam layer or a base layer.
13 . The device of claim 1 , wherein the flexible display comprises a cover glass that has a maximum thickness that is less than 200 microns, wherein a thickness of a non-resonating material over the cover glass is based at least in part on a quarter-wavelength of the ultrasonic signal.
14 . The device of claim 1 , wherein a thickness of the acoustics configuration layer is less than 50 microns.
15 . A device comprising:
a flexible display;
an ultrasonic fingerprint sensor that is configured to transmit and receive an ultrasonic signal in an acoustic path through the flexible display; and
an acoustics configuration layer,
wherein:
the acoustics configuration layer is configured to optimize a signal strength of the ultrasonic signal based at least in part on a configuration of one or more layers of the flexible display,
the acoustics configuration layer is formed from a resonating material that is configured to cause a first alteration of a transmission of the ultrasonic signal and cause a second alteration of a reception of the ultrasonic signal, the second alteration being different from the first alteration, and
a thickness of the resonating material is approximately 10% of the thickness of all layers of the flexible display.
16 . The device of claim 15 , wherein the flexible display includes a backing layer,
wherein the backing layer includes a recess,
wherein the device further comprises a stiffener that is positioned within the recess, and
wherein the stiffener is the acoustic configuration layer.
17 . The device of claim 16 , wherein the stiffener is positioned between the ultrasonic fingerprint sensor and a panel layer of the flexible display.
18 . The device of claim 16 , wherein the ultrasonic fingerprint sensor is positioned between the stiffener and a panel layer of the flexible display.
19 . The device of claim 16 , wherein the backing layer further includes a base layer, and
wherein the stiffener is positioned between the ultrasonic fingerprint sensor and a base of the recess that is in the base layer.
20 . A device comprising:
a display;
an ultrasonic fingerprint sensor; and
an acoustics configuration layer formed of a resonating material,
wherein:
the acoustics configuration layer is configured to optimize a signal strength of an ultrasonic signal based at least in part on a configuration of one or more layers of the display,
the resonating material is configured to cause a first alteration of a transmission of the ultrasonic signal and cause a second alteration of a reception of the ultrasonic signal, the second alteration being different from the first alteration, and
a thickness of the resonating material is approximately 10% of the thickness of all layers of the display.