Why Cars Need Those Dots on the Windshield

The dark dots located on the sides of the windshield are called “frits.” They serve a variety of functions that solve not only aesthetical issues but also practical ones. Normally, the design is built on the principle of a gradient, from large dots to smaller ones, which contributes to a smooth transition. It is also common to see an extra layer around the rearview mirror.

5-Minute Crafts grew interested in those black dots on cars’ windshields, which is why we decided to learn more about their functionality.

Why a dotted design was chosen

The dots are called “frits” and the whole stripe is called the “frit band.” This is baked-in ceramic paint that is almost impossible to scrape off. The pattern is a halftone, that is, the gradient moves from adjacent large points to small ones, which are located a little further apart from each other. It makes up the frit band that will be perceived by the human eye as a blurred line at a distance.

In addition, such a halftone pattern allows for a controlled temperature when manufacturing automotive glass. Their shape is slightly curved, therefore, the edges are covered with ceramics to prevent deformation from heat during production. The dots, in their turn, help to distribute heat evenly.

The same effect is obtained when driving on a hot day. Frits absorb a part of the heat directed at the windshield. Therefore, the high temperature is not concentrated on the edges of the glass, which contains glue that helps keep it in place.

What functions the frit band performs on the windshield

• The protection of polyurethane sealant is there to adhere to the glass. Its goal is not only to hold the glass in place but also to protect the cabin from rain and other precipitation. It’s important that it keeps its qualities for as long as possible. The frit band also helps protect the sealant from ultraviolet light, thanks to which the car is able to sit in the heat, under the burning sun, and its service life increases by a lot.
• Aesthetic reasons: The frit closes the adhesive layer located along the edges of the glass. In addition, the halftone pattern has a rough surface, which serves as an excellent aid for adhesion.
• The “third visor frit” is what the frits located on the windshield right behind the rearview mirror are called. Usually, this zone is expanded, and the dots located there differ in pattern from those along the edge. They help block out the sun’s rays that can’t be avoided behind the 2 front visors.