ALEXANDRIA, Va., March 17 -- United States Patent no. 12,578,187, issued on March 17, was assigned to SEOUL NATIONAL UNIVERSITY R&DB FOUNDATION (Seoul, South Korea) and CENTER FOR ADVANCED META-MATERIALS (Daejeon, South Korea).

"Apparatus for ultrasonically measuring thin film thickness with retroreflector and method thereof" was invented by Jeseung Lee (Anyang-si, South Korea), Jooa Park (Suwon-si, South Korea) and Yoon Young Kim (Seoul, South Korea).

According to the abstract* released by the U.S. Patent & Trademark Office: "A thin film thickness measuring apparatus includes: an ultrasonic retroreflector that is provided under a test object formed in the shape of a thin film and retroreflects an ultrasonic wave incident through the test...