Glass Tempering first patent in 1874, obtained by the French, tempered glass method is heated to its softening temperature glass 3c, immediately put into a relatively low-temperature liquid bath, the surface stress increase. This method of liquid steel that is earlier methods. Germany Frederick Siemens awarded a patent in 1875, Massachusetts Geovge E. Rogens in 1876 steel method is applied to glass tumblers and lamppost. In the same year glass door, NJ HughO'heill obtain a patent. Tempered glass can be traced back to the initial development of the mid-17th century, there was a king named Robert Rhine son, has done an interesting experiment, he put a drop of molten glass was placed in cold water, the result made a extremely hard glass. This particulate glass high intensity like drop, dragging with long curved tail, known as the "Prince Robert pellets." But when the pellets are subjected to bending and breaking the tail when it is strange that the whole arabica therefore sudden severe crash, or even become a fine powder. 4mm glass above approach, much like the metal quenching, which is glass quenching. This hardening does not make any change in composition of the glass tempered glass, so it is also called physical hardening (physical tempered), therefore called tempered glass tempered glass, also known as tempered glass.