Fingerprint imaging using CMUT impediography with glass waveguide

This paper discusses a method for fingerprint imaging, which involves applying an impedance signal to a fingerprint via ultrasonic impediography, using a capacitive micromachined ultrasonic transducer (CMUT). We explore the use of ultrasonic fingerprint imaging with impediography using a CMUT and a fingerprint phantom, and contrast the use of direct-touch and waveguide models. By using a waveguide in the middle of a wafer made of a hard material, the protection and stability of CMUT impedance signals are ensured. The measured impedance value is used to distinguish between the ridges and valleys of a fingerprint and create a fingerprint image by image processing. The images created using direct-touch and waveguide models are compared and analyzed.