99% of people don't know! What are the little black dots on the car windows used for?

People who often ride or drive

You may find a small detail

Edges of windows or windshield

There will be a circle of small black spots

Many people mistakenly believe

This is the manufacturer's sticker.

To make the car look more beautiful

What are these little black dots used for?

The answer

Maybe even experienced drivers with many years of experience don’t know this!

In fact, not all car windows have similar small black dots. Some windows have a small row of them, while others do not. The pattern may not be unique. Some are small squares, but most are round small black dots, and the pattern gets smaller and smaller until it disappears.

1

The windshield has a metal coating, and the area of ​​the black spot is empty, like a small window to allow the sensing signal to pass through.

2

Help electronic cameras on the road capture and focus.

3

Identifies the light sensing area for automatic headlights.

4

As a rain sensor for car automatic wipers.

Each statement seems to make sense, but there is no relevant evidence. So, what is the real scientific purpose of the black spots on the car windows?

01

Protect your car windows

In hot summer or cold winter, these small black spots can protect the car windows, reduce external damage to the windows, and make the window glass more durable.

The car glass is fixed to the car with glue. In the hot summer, when the car glass is exposed to the sun, the temperature of the metal frame around the car glass will rise and expand. The middle part of the glass has better light transmittance and heat dissipation, which forms a contrast with the edge of the glass. The heat is uneven, which can easily cause the glass to deform. Due to the poor toughness of the glass, the result of deformation is cracking, and at this time these black spots can play a role in heat conduction.

Similarly, in winter, when the temperature is low and the car is hot, the contrast between the surrounding frame and the middle is great, and there is also a risk of the car window exploding. The heat is concentrated by taking advantage of the principle that black absorbs heat quickly and dissipates heat quickly. Through this transition from the outside to the inside, the heat is gradually balanced, thereby achieving the effect of protecting the glass.

To put it simply, the window frame is hot, but the glass heats up slowly, so small black dots are needed to transfer the heat. These small black dots gradually become smaller from the window frame to the middle, which disperses the thermal expansion, reduces the pressure on the windows and windshield, and ultimately achieves an overall balance.

02

Protect your sight

In addition to the edges of the windows and windshield, some rearview mirrors also have small black dots. The location and area of ​​these black dots have been carefully calculated and designed to minimize obstruction of the driver's vision while reducing direct sunlight on the eyes, which helps to relieve driver fatigue to a certain extent.

03

Identification quality

These seemingly inconspicuous black dots have a rather complicated production process. Simply put, the principle is to burn colored glaze onto the glass, so that it becomes one with the glass and cannot be removed.

Some inferior glass is often used as a substitute, and some black spots or black edges will be pasted or printed on it. If these black spots can be removed, it means that the glass is of inferior quality.

The tiny black dots have an effect that cannot be underestimated

It's incredible!

Source: Xinhua News Agency, Science Popularization China, PetroChina

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