DEVICES INCLUDING ONE OR MORE HIGH-IMPEDANCE LAYERS BETWEEN A DISPLAY STACK AND AN ULTRASONIC FINGERPRINT SENSOR STACK

原文（中文）

An apparatus may include a display stack, an ultrasonic sensor stack and a high-impedance stack including one or more high-impedance layers. The ultrasonic sensor stack may include an ultrasonic transceiver layer and an ultrasonic transceiver circuitry (UTC) layer. Each of the high-impedance layers may have an acoustic impedance that is higher than an acoustic impedance of the UTC layer. The high-impedance stack and the ultrasonic sensor stack may form an acoustic resonator bounded by the UTC layer and the high-impedance stack. The acoustic resonator may be configured to enhance the ultrasonic waves transmitted by the ultrasonic sensor stack at a peak frequency of the ultrasonic sensor stack. The peak frequency may be a frequency used by the ultrasonic sensor stack for obtaining fingerprint images. An apparatus stack portion that includes the ultrasonic sensor stack may have a thickness corresponding to a multiple of a quarter wavelength at the peak frequency.