A Short History of Photosensitive Glass Patents

Abstract

The development of photosensitive glass (PG) has a remarkable history since its first commercial discovery in the 1940s. The manufacturing of PG is one of the most widely reported methods for special glass manufacturing. PGs are capable of forming permanent photographic images when subjected to light, providing security, high quality and productivity. The first U. S. patent about photosensitive glass was filed on December 8 th , 1943, and published July 18 th , 1950, by Stanley Donald Stookey. A historical perspective about photosensitive glass represents an important step for future applications. PG has been considered one of the most interesting research areas with potential industrial applications. A number of companies and institutions have explored the usefulness of such special glasses. In this paper, we investigated the number of published manuscripts and patents and determined the correlation of research activities to the production of new PG materials. The United States, Japan and China have been leaders in photosensitive glass development and have contributed to an impressive rise of activity in PG based on a number of new publications, author keywords, affiliations and primary characterization techniques. We verified that the number of published fundamental PG studies was greater from academic institutions than from industrial laboratories. According to the European Patent Office, more than 6,228 patents have been globally filed prior to 2013 with the terms "photosensitive" and "glass" within the title or abstract. These numbers have continued to grow along with worldwide PG-related sales. Based on the Scopus database, for the same period, 1,301 PG documents (primarily manuscripts) were published with the same terms in the title, abstract or keyword list. Statistically, there have been fewer worldwide publications of manuscripts than patents.