Have you ever noticed that dot matrix pattern at the top of some windshields? Most people assume it’s just a way to help shade the driver from the sun, but the little black dots actually do so much more.
There’s a black band of ceramic paint called a “frit” along the edge of a windshield that helps sealant adhesive stick to the glass. Not only does it keep the elements out, it actually helps the windshield stay in place. When the glass is heated and bent in an industrial oven, the frit heats up and expands. This creates an optical distortion in the glass, aka “lensing,” and the black dots help spread the sharp thermal gradient between optical glass and frit to minimize and mask the distortion. Learn more about these curious little dots in the video above.