Answer:
The black dots on car windshields are called “frit strips”. This is a ceramic glaze that is baked into the edges of the windshield during the vehicle manufacturing process.
The primary function of the “frit strip” is to provide a rougher surface to increase the adhesion area of the adhesive layer, ensuring stability between the windshield and the vehicle frame.
The second function of the “frit strip” is to protect the adhesive layer from the sun’s ultraviolet rays. Without the “frit strip”, sunlight will damage the adhesive layer and result in gaps in the glass edge allowing rainwater to enter the car.
In addition, the “frit strip” also brings aesthetic elements to the car because it cleverly conceals the adhesive layers that bond the windshield and the car frame.
So what is the function of the small black dots on the “frit strips”?
The first function of the “frit” dots is to deceive the eye. The “frit” dots gradually become smaller and farther apart as they get further away from the windshield edge, making it difficult for the driver to recognize the transition between the black color of the frit strip and the glass, avoiding distraction while driving.
The second function is to balance the temperature of the windshield. Due to its dark color, the “frit strip” absorbs more heat than the windshield, and the “frit” network will help distribute the heat more evenly at the boundary between the “frit strip” and the glass. This limits the distortion of the outside image, which makes it difficult for the observer.
In addition, the “frit dots” also have the ability to reduce glare from sunlight. Therefore, many car manufacturers also arrange a “frit” dot matrix behind the rearview mirror to increase the ability to shade the front seats.