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Auto-Dimming Mirror Guide: What They Are & How They Work!

Auto-Dimming Mirror Guide: What They Are & How They Work!

There are a ton of options to consider when you are looking at new cars.

Trying to decide which type of mirrors you’d like yours to have can be difficult these days with all of the new features that manufacturers are offering, like auto-dimming.

What does an auto-dimming mirror even do, anyway?

Auto-dimming mirrors help prevent glare by reducing the brightness of reflected light. Reducing its brightness ensures that drivers have clear views of the road. As a result, auto-dimming mirrors can improve your car’s safety profile.

Keep reading to learn more about how these mirrors work and the additional benefits that they provide! 

What Is an Auto-Dimming Mirror?

An auto-dimming mere works exactly how it sounds like it would. It can detect whenever bright lights are shining onto the mirror’s surface. Then, they are able to adjust, reducing the reflection’s brightness.

Most auto-dimming mirrors are made with an electrochromic material. These respond chemically to changes in electrical potential. 

In other words, they’ll look different if they’re exposed to a current.

Detecting oncoming lights makes it possible to anticipate changes. The best mirrors reduce reflections before you notice, making it safer to drive.

If you’ve got an auto-dimming mirror, you don’t have to adjust anything by hand. It’ll automatically correct itself if there’s a lot of light shining at you on the road.

Readjusting the mirror’s opacity limits how much light gets reflected.

That’s how they are able to prevent glares from blinding you when you’ve got to drive.

A popular way to create them is by using special electrically-sensitive materials. These materials are called electrochromic materials. 

They are able to change their properties by responding to electrical currents.

So, you can send a current through them if you’d like to reduce how much light they’re reflecting. 

Reducing the current automatically makes them reflect more light. The more light they’re able to reflect, the brighter the vision you’ll get to see.

The most sophisticated models use sensors to detect ambient light when you’re driving. 

That’s how they’re able to modulate the mirror before you notice anything at all.

How Do Auto-Dimming Mirrors Work?

Most mirrors use a manual control mechanism, so you’ve got to adjust them yourself.

Auto-dimming mirrors still let you control how they are positioned manually. But, you don’t have to change anything if you’ve got someone using their high beams behind you.

A set of photosensors rests behind the mirror’s surface, measuring oncoming light intensity. 

When there is a spike in light intensity, they’ll send a signal to a pair of electrodes inside of the mirror.

Sending a signal to the electrodes causes a current to jolt across the mirror’s surface. 

It’s made of electrochromic material, so it’s able to change its composition. The material begins to reflect less light once it’s been exposed to electricity.

The electrodes send a current through its surface as a result of bright external lights. 

These trigger the mirror’s photosensors, letting it know when to darken.

Electrochromic materials change appearance if exposed to an electrical current. That’s how engineers were able to design auto-dimming technology. 

Using an electrochromic material lets them design a mirror that dims when it’s bright out.

Electrochromic mirrors are definitely the most popular type of auto-dimming technology. However, there are a few other approaches you can use, too. 

The method used to build the mirrors determines how they’ll respond to ambient light in your car.

Some developers have begun using forward-facing sensors to detect ambient light. By detecting upcoming conditions, it’s possible to change the mirror’s orientation.

As a result, some auto-dimming mirrors change their angle according to ambient light. 

Tilting at a different angle can reduce how much light you’ve got in your eyes. 

The angle determines where photons go once they’ve come into contact with the mirror.

Are There Auto Dimming Side Mirrors?

So far, we’ve mostly discussed how auto-dimming tech works in the rearview mirror. Not as many side view mirrors a feature that technology, but it’s still out there.

Usually, people don’t deal with as much road blindness as a result of their side-view mirrors. That’s why they’ve taken a little longer to become popular.

They’re able to prevent cars from distracting you with a sudden burst of their high beams. 

Bright flashes only limit your vision for a few seconds, but they’ve got lethal potential. 

Using an auto-dimming mirror would make it impossible for them to blind you when you’re in the car.

Auto dimming side mirrors work almost exactly the same way rearview ones do. A pair of photosensors looks at how much light is hitting the mirror’s surface. Then, it’s able to adjust an electrical current to change how much light gets reflected.

If there is a ton of light, it’ll reflect less of it to prevent you from getting blinded. Some of them also use forward-facing sensors to detect how things will be ahead of you on the road.

Using that data makes it possible to make anticipatory adjustments when you’re driving.

The mirrors on both sides of the car use the same technology to function. 

Sometimes, manufacturers even link them together, so they are able to synchronize data. 

Synchronizing both sides creates a clear picture of lighting conditions.

By creating a picture of the external environment, it can decide how much current to make. 

Brighter conditions elicit a stronger response from the electrodes, making the current stronger.

As more current pulses through the mirror, it dims. Thus, sending less of it to your eyes.

Low ambient light triggers a signal, telling them to make less electricity. 

Reducing the current lets the electrochromic materials reflect more light.

One of the best things about auto-dimming tech would be how you’re able to benefit without doing much. Because of how they’re built, you don’t have to touch anything at all when you’re using them.

How Are Auto-Dimming Mirrors Safer?

Critics of auto-dimming mirrors believe there is not a huge benefit to installing them on your car. However, studies have shown that it’s safer to drive if you’ve got auto-dimming mirrors.

On the one hand, the critics have a point when they say you can just adjust mirrors by hand. 

You can adjust a regular mere by hand to prevent glares from blinding you while you’re driving.

The biggest problem with that is you’ll be distracted each time you’ve got to adjust them. 

Even the few moments distracted on the road could lead to an accident. 

Auto-dimming mirrors eliminate those distractions by automating everything.

You don’t have to change how you’re driving if someone pulls up with their high beams on. 

Even shining them directly at your face won’t be enough to make you blink. 

Your mirrors will automatically change how much gets reflected, protecting your vision.

Zach Reed

Hi, I'm the founder of! Having owned a wide variety of vehicles in my life, I was astounded at how hard it can be to find answers to common automotive questions. Rather than sit idly, I decided to create this website to help others!