QUALCOMM Incorporated
Layer for inducing varying delays in ultrasonic signals propagating in ultrasonic sensor

Abstract:

An apparatus includes an ultrasonic transmitter, an ultrasonic receiver, and an acoustic delay gradient layer disposed in an acoustic path between the ultrasonic transmitter and the ultrasonic receiver. The acoustic delay gradient layer is configured to cause a reflection from a platen interface of the transmitted ultrasonic signal to reach the first receiver region at a first time and the reflection from the platen interface of the transmitted ultrasonic signal to reach the second receiver region at a second time that is different from the first time. The apparatus can further include a controller configured to set for a first region or portion of the receiver, a first range gate window (RGW). The controller is also configured to set, for a second region or portion of the receiver, a second RGW, and to establish a first temporal delay between the first RGW and the second RGW.