As auto-mobiles gradually evolved from open-top designs to fully enclosed bodies, the number and size of automotive glass panels continued to increase.
At that time, however, only wind-shields used laminated glass to prevent shattering and splintering. Side windows and rear windows still used ordinary glass, leaving significant safety risks unaddressed. In 1938, good news arrived from Pittsburgh Plate Glass Company: tempered glass was successfully developed.
Through a specialised high-temperature and quenching process, this glass becomes 5 to 10 times stronger than regular glass. More importantly, even if it breaks under severe impact, it does not form sharp fragments, but breaks into countless small, blunt granules, greatly reducing injuries to drivers and passengers.
Once introduced, this technology was quickly applied to automotive side and rear windows, gradually replacing ordinary glass to become the mainstream choice. It marked a solid step forward in automotive safety protection.
This breakthrough also promoted the improvement of industry standards. Later, many countries successively issued regulations requiring the use of safety glass for vehicle windows, strengthening safety protection through legislation and making safety glass a standard component in auto-mobile production.