Seeing your phone screen while wearing sunglasses only takes a quick turn
The sun is coming back for another bright summer, which means it’s time to relax and read by the pool. So you pull out your phone, put on your sunglasses and… you can’t see anything on the screen. Which give?
This annoying phenomenon occurs with all kinds of electronic devices, including phones, tablets, and computer monitors. Even with the increased brightness, the screen appears dark, purple, or in some cases completely black when wearing sunglasses. The guilty? Polarizing filters.
How polarization works
You’ve probably heard of polarized sunglasses before, but to solve the problem, it’s important to understand why this “black screen” phenomenon occurs when you wear them. (Don’t care about the science? Skip to the end of this article for the quick fix.)
Light is made of particles called photons, which travel through space like a wave, zigzagging back and forth towards your eye. Unpolarized natural light is made up of photons that bounce in several directions at the same time. But as soon as they hit certain types of reflective surfaces – like a body of water or an asphalt road – these waves will all start to vibrate in one direction, usually horizontally. This is what causes the intense glare that hurts your eyes when you look at the sunlight on a lake.
Polarizing filters absorb light waves that vibrate along a certain axis. In the case of polarized sunglasses, they absorb the vibrating waves horizontally. This means that only vertically vibrating waves pass through the filter and reach your eye. This reduces the intensity of the reflective glare without blocking too much surrounding light.
Polarized lenses don’t just reduce glare; they also protect the long term health of your eyes. “Everyone should wear polarized sunglasses for maximum eye protection against UVA / UVB rays,” says Purnima S. Patel, clinical spokesperson for the American Academy of Ophthalmology.
Chances are, you’ve already followed this advice. There is just one problem: this is also the reason why you are having trouble seeing your screen.
How to see your screen without removing your shades
Your gadgets also contain polarizing filters. “These LCD screens are polarized to reduce glare, especially in direct sunlight, just like sunglasses,” says Patel. “When the screen filters and sunglasses line up in opposite directions, the light emanating from the screen is cut off.” In other words, if the screen is emitting a vibrating light horizontally and your sunglasses block everything except the vibrating light vertically, no photons will pass through and you will be stuck with a dark or all-black image.
Some devices will experience this effect worse than others. While many high-end devices have found ways around the problem (like the current generation of iPhones, iPads, and Google Pixel phones), you’ll still notice it to some extent on many phones and tablets.
Fortunately, there is a simple solution: turn the screen 90 degrees back and forth. This will align the polarizing filter on your screen with that on your sunglasses, and light from your screen will be able to pass through your eyes.