We are sure that the black dots on the upper edges of the windshields of cars have caught your attention. However, most people do not know what its name is and what it does; Because no one would even think that it would be a very important detail. So what are they and what do they do?
These little dots are called frits. These points, which are made of baked ceramic paint and cannot be removed, have three purposes: structure, security and aesthetics. First of all, frit tape is vital to keep the windshield attached to your vehicle. It’s actually a pretty clever and multifunctional strip: The rough ceramic paint not only provides a better, grippy surface on the urethane sealant that connects the glass and the vehicle frame, but also protects it from ultraviolet light, which can cause that adhesive to break down.
But that’s not the only good thing about science. Frits also serve as protection: The dot matrix, a pattern of smaller dots that melt into the center of the panel, helps reduce an optical distortion known as “lensing.”
This effect is actually mostly seen during the creation of the windshield, an engineer from Pittsburgh Glass Works told Jalopnik. To bend the glass, window panels are exposed to heat of over 700 degrees Celsius, and a thick black band around the edge absorbs this thermal energy much faster than clear glass.
But a sharp heat gradient like this causes uneven refractive indices across the windshield, causing straight lines to appear curved or bent toward the center of the glass. Since driving is easier when you can see clearly, the dot matrix is a good solution to prevent this effect from occurring. Frits can also prevent the sun from entering between the visors in modern vehicles and blinding you on the road.
The thing is, frits are not just meaningless patterns with a funny name, they are an important invention of automotive engineering.