Ultrasonic fingerprint apparatus and electronic device

An electronic device, comprising:

• a display;
• and
• an ultrasonic fingerprint apparatus, wherein the ultrasonic fingerprint apparatus is disposed under the display to implement under-display ultrasonic fingerprint recognition, the ultrasonic fingerprint apparatus comprises an ultrasonic fingerprint chip and a piezoelectric transducer disposed on the ultrasonic fingerprint chip,
• wherein:
• the piezoelectric transducer comprises a piezoelectric layer, an upper electrode on the piezoelectric layer, and a lower electrode under the piezoelectric layer;
• and
• the ultrasonic fingerprint chip is a complementary metal-oxide-semiconductor (CMOS) chip, the upper electrode is led out from an upper surface of the piezoelectric layer to a surface of the CMOS chip, and is connected to a circuit board through a pad on the surface of the CMOS chip, to implement an electrical connection between the piezoelectric transducer and the circuit board;
• wherein the ultrasonic fingerprint chip comprises a substrate and a plurality of metal layers provided in a first region of the substrate, the substrate is a silicon substrate, the lower electrode is located on a second region of the substrate, a top metal layer of the plurality of metal layers comprises N drive traces, N being 1 or a positive integer greater than 1, the upper electrode is connected to N pads via the N drive traces respectively, and the N pads connect the N drive traces to respective leads.