Recently many people complained that they can’t see the iPhone screen correctly when wearing polarized sunglasses after replacing their screen in a Third Party Mobile Repair Store. This has nothing to do with the quality of the screen that was used to replace your screen. In order to figure out why this happened, we’ve collected some data to share with you to explain this issue.
First we need to know the structure of the LCD screen and how it works!
As you can see from the picture above, each LCD screen contains backlight unit, rear polarizer (near to backlight unit), TFT array, liquid crystal, color filter and front polarizer (nearest to the screen’s display).The cause of all your problems in this case are the polarizers, which are used to filter the light. It allows the light in various angles to pass and effectively eliminate the extra glare. The polarizer plays an important role in display image quality and performance.
Speaking of the polarizing film, we need to know the working principle of a polarizer. It allows specific directions of light to go through. That explains why the color fades when looking at your screen from various angle while wearing polarized sunglasses because your naked eyes cannot see this. When you put both polarizers in perpendicular angles you can’t see any light going through. When wearing polarized sunglasses, you add a third layer of polarizer which makes it difficult for you to see properly just like the pictures shown below.
These two polarizers here mimicking you wearing your glasses while looking at a polarized glass. The front polarizer is equal to your polarized sunglasses, and the other polarizer is equal to the one in your phone (the one near the display), you can see the magic cube clearly when the 2 polarizers are parallel to each other, as the angle change, less light can pass through the polarizer and the magic cube seems to fade away.
Here we found some other cellphones also encountered this phenomenon.
For example, when you test with a Samsung Galaxy S5, when you put it at 45°, the screen gets black, other angles are fine.
On the Meizu you can see it clearly in a 90° angle, however when you put it horizontally, the screen gets completely dark.
You can see clearer examples on the iPhone screens with different shades of colors.
And for iPhone 6 series, there is only little discoloration on the screen.
Luckily, LCD display technology has been quietly evolved in recent years, more and more cellphones are tending to improve their screen technology, and the polarizer issues can hardly be found in smart phones now.
Conclusion:
For China made screens, most of the factories are currently using third party polarized films instead of OEM ones because it's much more expensive. According to our research, you may experience this problem in nearly half of all China made iPhone screens