What Are Those Small Black Dots Around the Windshield Of a Vehicle — and Why Are They There?

Whether you rent a vehicle or own one, you likely have noticed a gradation of black dots around the perimeter of the windshield, as they have become more prevalent in vehicles in recent years — and you might have wondered what is their purpose and why they are even there. Is it simply a design?

What Are Those Small Black Dots Around the Windshield Of a Vehicle — and Why Are They There?

The windshield of a vehicle is arguably one of the most important elements to maintain its structure and the safety of the driver and its passengers in the event of an accident, for if the structure is compromised in any way — such as a crack as one example — that could potentially present a dangerous situation for the occupants of the vehicle.

The black dots — many of which are round, although some can be more angular or striped — actually have a name, as they are known as frits. Each frit is painted black enamel which is baked in to the glass around the borders of a windshield during the manufacturing process. The part of the windshield which is closest to the frame of the vehicle is usually solid black; and as the black progresses towards the middle of the windshield, the solid black gradually diffuses from larger dots to smaller dots before the windshield — and, perhaps other windows of the vehicle — becomes clear glass…

…and at least five reasons explain why they are there in the first place, as frits:

1. Create a “dot matrix” or “halftone” pattern that actually help to dissipate and distribute temperature evenly to lessen optical distortion of the windshield — which is known as “lensing”, which happens when the solid black band heats up significantly faster than the glass of the windshield and thereby creating an optical distortion of straight lines appearing to be curved or bowed inwards toward the center. Those “gradually sinking” black dots help to reduce this phenomenon by dissipating the heat and spreading it out evenly.
2. Serve as a contact point between the glass and frame of the vehicle, as they create “etches” on the surface; and the rougher surface improves the bond which the adhesive has to the glass. A technician uses the frit as a bonding point between the glass and the frame when the windshield needs to be replaced or repaired.
3. Help preserve the urethane sealant — which is designed to last a long time — that is used to bond the glass to the frame of the vehicle, as the black enamel outside the windshield is used to block the ultraviolet rays of the sun from melting the adhesive underneath the band, which keeps the windows firmly glued in their place. Continuous exposure to direct sunlight can eventually damage or weaken the adhesion over time.
4. Are on the window for for aesthetic purposes, as they provide a polished appearance as they conceal the adhesive.
5. As a “dot matrix” or “halftone” pattern allow a gradual decrease in size that renders the transition as substantially more subtle and easier to the eyes, as the contrast between the dark band and the transparent glass can look too obvious even when viewed from afar.

In other words: without frits, the glass could possibly become loose and eventually fall out of the frame — which is about as unlikely as an emergency situation aboard an airplane during a flight.

The latest models of vehicles have “third visor frits” added right behind the rear view mirror to block the sun between two sun visors — and some manufacturers of vehicles have also become more creative by using either their brand logos or unique graphic images as substitutes for plain small black dots.

Final Boarding Call

Now when you see those small black dots around a windshield, you no longer have to fret about what purposes frits serve, as you now know.

All photographs ©2022 by Brian Cohen.