Why are foldable smartphones needed at all?
There are many arguments. The main ones are:


1. Foldable smartphones are the most technologically advanced in the world. This is perhaps the main breakthrough since the advent of touchscreen devices.
2. A large display when needed. And a compact size when folded. That's cool. And how impressive it is to open the device, pulling it out of your pocket!
3. Great functionality. Foldable smartphones can be used as tablets or even mini-laptops. Or take professional-quality photos without a tripod and photographer.
4. Why, you ask? They are foldable!
What is special about foldable displays, besides flexibility?
 

Samsung's flexible smartphone screens are called Dynamic AMOLED 2X. This is the latest generation of displays that delivers color gamut with 100% accuracy*.
And the display of dynamic scenes and scrolling is incredibly smooth thanks to a refresh rate of 120 Hz.
The flagship Samsung Galaxy S23 Ultra smartphones are equipped with the same screens. Let's figure out how they are structured.

AMOLED stands for Active Matrix Organic Light-Emitting Diode. Here, each diode works as an independent light source.
This is the main difference from IPS screens, where a lamp illuminated the entire liquid crystal matrix, and then the rays hit the pixels.
In AMOLED displays, each diode is a pixel. It lights up and delights us all. And when it doesn't light up – it still delights.

If we break down the AMOLED display into layers, we get the following picture:

1. Protective glass.
2. A sensor that reads finger touches on the screen.
3. The same light-emitting diodes.
4. Transistors that supply voltage to the diodes.


At first glance, flexible and regular displays do not differ. The devil is in the details.

It is obvious that a classic OLED matrix is not designed for bending.

To make the bent display continue to work, Samsung engineers needed a material that would create something like a flexible frame and hold all the elements in place.

Such a material was found - it is a flexible and durable polymer that can fold and unfold thousands of times as if nothing happened.
This polymer became the basis of the "infinitely flexible" Infinity Flex displays. And the screen is protected by Corning Gorilla Glass Victus - incredibly wear-resistant, flexible, and strong.

Another "bending element" is the hinges in the smartphone's body, which allow the device to bend mechanically.
In the folded state, there is a tiny gap between the two parts of the screen. This is done intentionally so that the two halves of the display do not rub against each other.

You can also bend the smartphone at different angles thanks to the hinges.
For example, to open a large screen or place the semi-folded body on a hard surface to take clear photos and videos without a tripod.

The Fold4 and Flip4 smartphones are water-resistant (protection rating - IPx8). This includes the hinges and the display. Therefore, the devices are not afraid of real life and serve for a long time.