That is why there are black dots along the edge of your car windows
You may have noticed: there are hundreds of black dots along the edge of your car windows. They are not there for the show but perform several essential functions.
The dots, which are literally baked into the edges of the car window in the glass factory, are all about the glue used to install the windshield. Firstly, due to the rough surface, they ensure that the adhesive adheres better to the glass.
In addition, the dark dot border acts as a shield to protect the adhesive from ultraviolet rays of the sun. It would otherwise be weakened by continuous exposure to UV radiation. In addition, the dots also have an aesthetic purpose: it hides the glue nicely.
The dots help to distribute the temperature during car window manufacturing evenly. This reduces the so-called optical distortion in the glass. Namely, when windshields are made, they are bent in a hot oven. During that process, the black belt heats typically up much faster than the glass. The ‘fanning out’ black dots help to reduce this phenomenon by evenly dissipating the heat.
Finally, the small black dots also ensure a visually more pleasant transition from the black edge to the transparent glass. The dots can also often be found above and next to the interior mirrors of many cars. Here it is mainly intended to remove annoying sunlight and thus prevent you from being blinded when you look in the rearview mirror.