Ultrasonic fingerprint sensor with a contact layer of non-uniform thickness
摘要
說明書
In other embodiments, an image is captured at an ultrasonic sensor using a temperature to control the transmission frequency, according to embodiments. An imaging operation is performed at a two-dimensional array of ultrasonic transducers of the ultrasonic sensor to generate a plurality of pixels, wherein the ultrasonic sensor has a contact layer having a non-uniform thickness overlying the two-dimensional array of ultrasonic transducers and wherein the two-dimensional array of ultrasonic transducers is substantially flat. A temperature of the ultrasonic sensor is determined. A transmission frequency of activated ultrasonic transducers is controlled during the imaging operation, wherein the transmission frequency is controlled based on the temperature of the ultrasonic sensor. The transmission frequency is selected to generate a constant interference pattern across all temperatures. At least one fingerprint image is captured using the transmission frequency. An interference pattern correction is applied to the fingerprint image to generate the output fingerprint image.
