US 12,169,977 B2
Under-display ultrasonic fingerprint sensors for foldable displays
Shiang-Chi Lin, Taoyuan (TW); Hrishikesh Vijaykumar Panchawagh, Cupertino, CA (US); Jessica Liu Strohmann, Cupertino, CA (US); Yipeng Lu, Moraga, CA (US); Chin-Jen Tseng, Fremont, CA (US); Kostadin Dimitrov Djordjev, Los Gatos, CA (US); Min-Lun Yang, Miaoli County, Hsinchu County (TW); and Chia-Wei Yang, Hsinchu (TW)
Assigned to QUALCOMM Incorporated, San Diego, CA (US)
Filed by QUALCOMM Incorporated, San Diego, CA (US)
Filed on Oct. 13, 2023, as Appl. No. 18/486,914.
Application 18/486,914 is a continuation of application No. 18/302,241, filed on Apr. 18, 2023.
Application 18/302,241 is a continuation of application No. 17/446,436, filed on Aug. 30, 2021, granted, now 11,798,307.
Prior Publication US 2024/0037979 A1, Feb. 1, 2024
Int. Cl. G06V 40/13 (2022.01); G01S 7/52 (2006.01); G06F 21/32 (2013.01)
CPC G06V 40/1306 (2022.01) [G01S 7/52079 (2013.01); G06F 21/32 (2013.01)] 28 Claims
OG exemplary drawing
 
1. An apparatus, comprising:
an ultrasonic sensor stack;
a display stack, comprising:
a display stiffener; and
display stack layers configured to cause ultrasonic waves transmitted by the ultrasonic sensor stack to have one or more display stack-induced local amplitude maxima in a first ultrasonic frequency range; and
a transmission enhancement layer configured to, when coupled with the display stiffener create a transmission enhancement resonator that has a lower acoustic impedance in the first ultrasonic frequency range than does the display stiffener without the display stiffener being coupled with the transmission enhancement layer.