Brief history of the flat glass patent – Sixty years of the float process

• The float process: the predominant method for flat glass manufacturing explained.
• Historical context: one of the greatest process inventions of the twentieth century.
• Strong patenting from 1953 to present day.
• ‘Float’ is so innovative that since 1959 it has largely supplanted other flat glass techniques.

This paper deals with one of the single most important innovations made in Great Britain since World War II. It is certainly one of the greatest process inventions of the twentieth century. The float process is one of the most widely used methods for flat glass manufacturing as it ensures security, high quality and productivity. From a historical point this innovation was the beginning of a revolutionary change in the mass production of flat glass for the building and automotive sectors. More specifically this innovation eliminates the traditional operations of rolling, grinding and polishing the glass surface while creating a high quality and inexpensive flat glass product. The first patent was applied for on December 10th, 1953 by Pilkington and Bickerstaff. This paper presents a brief discussion from the 1960s in a historical perspective about this amazing discovery and the main patents related to it. More than 23,900 patents using the term “flat glass” have been filed around the world, according to the European Patent Office databases. These numbers just continue to grow as do total sales worldwide. Looking for titles using flat glass, we found 2,409 patents filed. Curiously, for the same period 1,131 patents were published with float glass in the title and just 3,995 with the term in the title or abstract. So, statistically, there are more published patents using the term ‘flat’ than ‘float’ glass process.