US 12,217,530 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 (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 Apr. 18, 2023, as Appl. No. 18/302,241.
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 2023/0252816 A1, Aug. 10, 2023
This patent is subject to a terminal disclaimer.
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)] 30 Claims
OG exemplary drawing
 
1. An apparatus, comprising:
an ultrasonic sensor stack;
a display stack, comprising:
a high-impedance layer having an acoustic impedance of 10 MRayls or more; 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, wherein the high-impedance layer and the transmission enhancement layer comprise a transmission enhancement resonator configured to cause the ultrasonic waves transmitted by the ultrasonic sensor stack to have a transmission enhancement resonator-induced local amplitude maximum in the first ultrasonic frequency range;
wherein the transmission enhancement resonator-induced local amplitude maximum corresponds to a frequency in a range from 5 MHz to 15 MHz.