What is the black area on the windshield?

[CamilleMarie]

The black dots help distribute heat evenly and prevent windshield cracking. Reasons for windshield breakage include: 1. Poor tempering of the glass itself: Tempered glass inherently has a 0.3% spontaneous breakage rate due to quality issues, which strictly speaking indicates glass quality problems. 2. Uneven heating during installation: If insufficient edge clearance is left during installation, the glass expands when heated and presses against the metal frame, causing uneven stress and breakage. 3. Uneven heating during film application: During tinting, if the glass isn't heated uniformly (e.g., using a hair dryer to shape the film), localized heating creates expansion stress that can crack the glass.

[JordanDella]

I've been a mechanic for 15 years. That black border is called the 'ceramic frit layer,' which is directly fused to the glass edge using high temperatures. Its main purpose is to conceal the windshield adhesive and prevent the glue from aging and cracking due to sun exposure. If you look closely, the black border area also houses the rain sensors and camera wiring—the solid black background ensures the electronic components function accurately. When getting window tint for your new car, pay special attention: never let the technician apply the film inside the black border, or it'll start bubbling at the edges within six months. Also, if you replace the windshield and the black border doesn't align with the car's waistline, the entire vehicle will look off.

[LeJoanna]

I remember the first time I washed the car, I curiously touched that area, and now I know it's actually a 'UV protective layer' for the glass adhesive. The entire car relies on this black adhesive to hold the glass in place. Prolonged exposure to sunlight can cause ordinary adhesive to yellow and crack, while the dark glazed surface can block 80% of UV rays. The most practical feature is the row of gradually smaller dots along the upper edge, which help reduce dashboard glare during midday driving. Once, I drove a friend's modified car where he had patched the edges with black glass adhesive himself. However, under the sun, the adhesive bubbled and cracked, making it unsafe instead.

[AshleyFitz]

As an automotive designer, I must say that the black border is the 'edge trim' of the entire glass. The edges of the windshield can be quite sharp after cutting, and applying the black border smoothens the edges. That curved black band connects with the A-pillar, making the roofline flow more seamlessly. High-end vehicles even utilize a gradient-tinted sunshade area to project the brand logo—when driving, the dashboard reflects the logo's light and shadow perfectly. If a replacement glass during modifications has an insufficient black border width, the wiper park position will be exposed, looking very awkward on the exterior.