Curious about the operation of foldable phone screens? Do you understand their opening and closing procedures?

All those vibrant hues are laid on a layer of material known as the display panel. Years ago, the display panel was a thin sheet of fragile glass, prone to breaking with low durability. However, over the past decade, screen manufacturers have researched and developed display panels made of flexible plastic that can bend without shattering.

The advent of plastic screens has led to the emergence of unique curved-screen phones, notably Samsung's pioneering Galaxy Note Edge released in 2014.

As technology advances, screen manufacturers relentlessly explore ways to enhance the flexibility of plastic displays safely. This not only addresses durability concerns but also enables screens to bend thousands of times without damage.

This paves the way for today's foldable screens, allowing us to fold phones without worrying about screen breakage.

Flexible display panels are just one piece of the phone manufacturing puzzle. Scientists and engineers also tackle other formidable challenges, such as creating lightweight and flexible panels that withstand mechanical pressure over time, ensuring that bending and folding operations do not degrade image quality.

Engineers must devise a flexible protective layer for the screen and ensure that all other technologies applied to the screen continue to function normally.

Once all these requirements are met, another team must brainstorm ways to integrate the flexible screen into foldable phones while maintaining the extremely high standards demanded by manufacturers. It's truly a daunting task, which is why it can be said that bringing a perfect foldable phone to users requires a great deal of dedication from manufacturers.

Delve deeper into how foldable screens work

One thing you may not know is that all current foldable screens on the market are OLED. OLED screens do not have a backlight like LCDs; instead, pixels emit light on their own when powered.

This is why OLED panels are typically thinner and lighter by about 30% compared to LCDs. With many other benefits, OLED has been chosen for flexible display production, although flexible LCD displays still exist, but are relatively rare.

To envision how flexible OLED foldable screens work, think of it like a very thin layer cake. Each layer of this technology cake has a specific role, pieced together into an extremely thin package, only millimeters thick.

• The substrate layer, also known as the motherboard, is the main layer of the screen, supporting all other layers. Most modern foldable screen devices use a substrate made of a plastic polymer called polyimide (PI). Due to its flexibility and insulation, polyimide has high mechanical strength and stable temperature.

• The TFT layer is used on the surface of the screen, controlling the energy supply to each pixel. It can be seen as an 'electric grid' layer connecting all pixels on the screen. Unlike LCDs, on OLED screens, each pixel can be individually controlled, providing high contrast and low power consumption.

• The OLED layer is the light-emitting layer formed from individual pixel points, each pixel consisting of subpixels in three colors: red, green, and blue. Each pixel can achieve a certain color and brightness by varying the amount of power its subpixels receive. These pixels combine to create the image we see on the screen.

• The cover layer, also known as the encapsulation layer, is the sealing and protective layer for other layers. It's also the layer users directly touch when interacting with foldable screens, typically made of polyimide. Recently, it's also made from ultra-thin glass (UTG). Samsung has been using this material on its latest Z Flip and Z Fold phone series.

Other interesting facts about foldable screens

There are currently two types of foldable screens: inward-folding and outward-folding. Inward-folding, like Samsung's Galaxy Z Flip series, hides the screen inside the device when folded, contributing to durability but may tend to develop slight creases on the screen.

As for outward-folding screens, the standout is the Huawei Mate XS 2, with its uniquely curved display on the outside, leaving no creases on the screen. However, it's prone to scratches, which can be bothersome during use.

Most foldable phones on the market today can only fold once. However, Samsung has hinted at a phone that can fold two or even three times, the Samsung Flex In & Out series utilizing 'multi-foldable' technology.

There's also a type of foldable screen that doesn't require 'folding', which is quite unique. They're designed to be flexible, capable of rolling up and almost disappearing inside the device, exemplified by the OPPO X 2021 phone recently showcased by OPPO.

Apart from the screen, the hinge is also a crucial aspect in the production of foldable phones. Manufacturers have put in a lot of effort and dedication to create extremely sturdy, smooth, consistent hinges that are also suitable for mounting on phones without causing uncomfortable creases on the screen.

Another equally important factor is durability. In reality, the ability for the screen to fold can cause internal components to shift, leading to external factors such as water, dust, and pollutants easily infiltrating the device. There have been many cases where multiple shards were found under the screen, significantly affecting user experience, and screen damage is inevitable.

Nevertheless, with the continuous development of technology and evolving user needs, electronic device manufacturers are constantly seeking ways to develop more and more foldable screen technology products. The future holds promise for experiencing many modern devices with unique foldable screens and high durability.

Conclusion

So there you have it, 24h Technology has explored how foldable screens work with you. Do you like this type of screen? Are you planning to get a phone with such a convenient screen? Leave a comment below and let us know!

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• Galaxy Z Fold series slashing prices by over a dozen grands, it's time to upgrade!