Here’s What Those Black Dots On Your Windshield Are For

You’ve probably noticed those little black dots along the outer edge of the glass while scraping your windshield or just looking out the window while driving in your car. There’s usually a pattern to them, with the dots getting smaller and further apart before disappearing. I’ve always wondered what those were, too. Over the years, I’ve heard a couple of explanations: that they were part of the radio antenna system or it helped defog and defrost the car. Neither is true.

Notice that the dots emanate from a black border, called a “frit.” They’re made from a ceramic enamel paint that’s baked onto both sides of the window’s edge, which makes them almost indestructible. So what do dots and frits actually do?

1. Help secure the window glass: On the inside of the window, the frit creates a bonding point for the adhesive that attaches the window to the vehicle’s frame. They hold the glue in place, which holds the windshield in place.
2. UV protection: On the outside, the black dots help protect the adhesive from the sun’s UV radiation, which can degrade the bond between the car and the glass. It also gives the people in the car an additional measure of protection from the sun while driving.
3. Temperature control: In addition to the visual effect, the dots also provide temperature control. Window and windshield glass must be heated and bent into shape before being installed. Black-painted glass heats faster than the rest of the window. The dots distribute the heat more evenly, which prevents the windshield from warping in the heat.
4. Concealment: Frits also hide the adhesive from view.

The dots also make a more aesthetically pleasing transition from the thick black lines to the transparency of the window. The dots aren’t randomly placed; they’re positioned in what’s known as a “halftone pattern,” getting smaller and farther apart as the black recedes. This pattern is less jarring to the eye than opaque black paint juxtaposed with transparent glass.

Prior to frits, older cars used a gasket and metal trim to hold the windshield in place, which could lead to the glass popping out in an accident.

Do All Cars Have Black Dots On the Windshield?

Most cars do. Manufacturers have been using frits with auto glass for several decades now, so unless you’re a classic car collector, it’s hard to find one without them.

Do the Windshield Dots Wear Off?

Yes. Over time, the dots on your windshield can start to wear off and fade. This can expose the adhesive to the elements, like harsh sunlight, weakening the bond that secures the glass to the car. If you start to notice the dots wearing off, you should take the car to an auto glass specialist. In some cases, they might be able to repair it, or the glass may have to be replaced entirely.