In the technology of the 50s and 60s, metal was often used to frame the windshield. As technology developed, glue began to be used instead.
In fact, it is a revolutionary change, nowadays it is possible to come across these points in a modest car or a luxury car.
This black dot matrix strip is called a frit.
Frit is a type of ceramic paint applied with high heat. It is fired at the edges of the glass during production. It is not possible to scrape from glass.
It strengthens the contact between the glass and the car frame.
It allows the adhesive to adhere better to the glass, which is made possible by creating “carvings” on the surface, making them rougher. Since the adhesive is not visible, the ugly appearance is also prevented.
The urethane sealant that adheres the glass to the frame is protected from ultraviolet rays emitted by the Sun, as it remains under this black band. In this way, the adhesive is prevented from melting and a danger that will prevent the glass from sticking tightly is prevented. In addition, thanks to the strong adhesion of the glass, rainwater is prevented from entering.
So why is the transition between glass and frit in the form of shrinking dots?
Because the dots are black, they heat up more than other parts of the glass. This design distributes heat evenly across the glass, reducing optical distortion or lensing that may occur on the glass. The reason for having more on the windshield is to minimize distortion.
In addition, if this smooth transition did not exist, the sharp color difference that would occur would not look aesthetic and would be noticeable even from afar. In this way, an aesthetic appearance is provided as the transition is thinner.
Sources: Science ABC, techWORM, Bright Side