公开(公告)号：US20210146716A1

公开(公告)日：2021-05-20

申请号：US16622606

申请日：2019-02-22

Applicant: Master Dynamic Limited

Inventor： Siu Lung LUI ,  Yingnan WANG ,  Jianxing HUANG

IPC: B44C1/22 ,  B44B3/00 ,  B41M5/26 ,  A44C17/00 ,  B28D5/00

Abstract: A method of forming a non-optically detectable identifiable marking invisible to the naked eye is formed from plural recesses of multiple levels at an outer surface of an article formed from a solid-state material. The method includes forming plural recesses of multiple levels within a predetermined region of a photoresist applied to an outer surface of an article formed from a solid-state material. The plural recesses are formed by grayscale lithography and the recesses extend at least partially through the photoresist and towards the outer surface of the article formed from a solid-state material. The method also includes applying an etching process such that at least a portion of the outer surface of said article is exposed and etched to form plural etched portions extending into the article from its outer surface and corresponding to plural recesses; wherein said predetermined region of said photoresist defines an identifiable marking to be applied to the outer surface of said article; wherein said plurality of etched portions forms the non-optically identifiable marking on the outer surface of said article.