
How it all began: flexible and folding displays - the story of the appearance and exit of "people"

Samsung introduced a folding Galaxy Fold smartphone, and Huawei immediately responded with a flexible Mate X model. Other companies are developing similar devices, not only smartphones, Lenovo announced the imminent appearance of a laptop with a folding display . Folding screens are one of the varieties of flexible displays, however, not everything is flexible there, but only one area. So far, such matrices are still a rarity, therefore there are more questions about them than answers, but let's try to sort things out.
From dreams to real prototypes
The first were science fiction. In books and movies, the main characters used the most unusual devices, among which there were gadgets with flexible and folding screens of all colors and sizes.
1974 - the first real attempt. The
practical implementation of the idea was proposed by Xerox, or rather, one of its divisions - PARC. The developers have created a flexible electronic paper Gyricon. It appeared in 1974, technology was the beginning of the evolutionary path of flexible displays. "Paper" consisted of polyethylene spheres from 20 to 100 microns in diameter. Each sphere was composed of a negatively charged black and a positively charged white half. All spheres were placed in a transparent silicone sheet, which was filled with oil so that the spheres rotated freely. The polarity of the applied voltage to each pair of electrodes determined which side the sphere would turn, thus giving a white or black color to a dot on the display. Gyricon was flexible, it was possible to erase and overwrite the image on the sensitive layer thousands of times.
1989 - Gyricon as a Flexible Display Option Gyricon

Electronic Paper, 1989 version. Source: Сomputerworld
Nicholas Sheridan, while working at the Xerox Palo Alto Research Center (PARC), was looking for an opportunity to save paper from offices by providing an alternative - electronic paper, which withstood thousands of usage cycles. Gyricon, in his opinion, was an excellent candidate for this role. In 1989, he came up with a new idea - to develop flexible displays based on his invention.
90s of XX century - Xerox is trying to market its flexible displays

In the 90s of the last century, technology was patented and began to work on the project more actively. True, the use of such displays for commercial purposes was first tried only in 2003. Xerox hoped that soon it would be possible to arrange mass deliveries of Gyricon-based flexible displays to the market, especially since just at that time mobile phones began to appear in large numbers, for which a flexible display was an excellent option - after all, flexible material will not break, it’s not glass. Unfortunately, the cost of displays from Xerox was too high for it to interest vendors of electronic devices. They decided to close the project in 2005, but Xerox is still a patent holder.
2005 - New Development by HP
In 2005, another team of researchers, this time from HP, began working on a flexible color display. But this project had to be closed, because the developers did not have time to prepare a working demonstration prototype for the planned date. HP still has the technology the company was trying to work with. But in 2010, the direction was finally closed, as it turned out that thin and light glass screens are more profitable than more massive flexible screens .
2010 - Samsung color flexible display
In 2010, Samsung showed an excellent color flexible display that displayed all colors vibrant and vibrant. The screen size was 4.5 inches, and its resolution was 800 x 480 pixels. After that demonstration, it became clear that within a few years, flexible displays will enter the market.
Next came the flexible E-ink display developed by Human Media Lab. It was not just flexible - the sensors located in the screen tracked the degree of bending of the surface, generating an electrical signal as feedback.
This made it possible to develop screens that performed certain actions in response to the effort exerted by the user. For example, by bending the right corner, you could return to the previous page, the left - to start the application.
Even a flexible phone with an E-ink screen was introduced, which bent in response to an incoming call or message. Thus, a person could immediately understand that someone wants to contact him.
Unfortunately, both technologies were very crude. It was just a demonstration of the capabilities of engineers, so all this did not go into production, remaining at the concept level. It was still impossible to develop a real device that could become popular at that level of development of flexible displays.
2013-2017 - the emergence of modern promising projects
A similar concept was the Nokia flexible phone, introduced in 2011. Then she created her own concept and Samsung Corporation, showing a prototype in 2013.
It was this South Korean company that began to actively develop and promote the idea of flexible screens for smartphones. No less zealously rushed to invent a “bicycle” and LG. At CES 2013, the company demonstrated several devices with flexible screens. These were already quite functional gadgets. A little later, one of the technologies - a rounded screen surrounded by ordinary glass - became part of the Samsung product line as Edge smartphones.
Over the next few years, companies continued to demonstrate concepts until in 2017, Sony introduced the first commercial product - the FES Watch U smartwatch with a curved E-ink screen with integrated electronic components. Actually, the watch was a screen - both a dial and a strap. The user could change the color of the entire device, as well as its individual elements.

There were a lot of concepts, it is simply impossible to list everything within the framework of one article. And most of them remained projects, ideas that were never realized.
Real projects, not proof of concept
The first was a little-known startup Royole. The company showed its phone at CES in January 2019 and soon launched it on sale . The diagonal of the gadget when unfolded is 7.8 inches. According to the journalist who tested the device at work, the gadget had many shortcomings, the product was raw.
Then came Samsung's lineup with its Galaxy Fold. The company announced the device at the end of January 2019, announcing a price of $ 1980 .

The corporation sent the device to reporters of the Western media, who quickly discovered a large number of flaws in the design of the device.

Huawei similar smartphone called the X Mate .
According to company representatives, the device can be folded about 100,000 times without any harm. True, Samsung said about the same, but, as it turned out, not everything is so simple.
Another phone with a folding display introduced Xiaomi - Mi Flex Dual. Its display consists of three parts, not two. While this is a working concept, and its cost is unknown.

Lenovo talked about the upcoming laptop with a folding display. This is a nameless representative of the ThinkPad X1 family, which will appear on sale only next year. Some display characteristics are known. Screen size - 13.3 inches, type - OLED, resolution - 1920 × 1440. Making the screen for Lenovo will be LG.
Another is called Nubia Alpha. A flexible screen allows you to put the gadget on your hand like a watch. The device has the functions of a smartphone and will cost 499 euros. With it, you can make calls, send and receive messages, watch movies and take pictures.
Why so expensive
Firstly, because companies invest a lot of money in developing new technologies. Only Samsung has invested at least $ 2 billion in the current technology of flexible OLED displays in a few years. The company hopes to return all this, so phones with flexible screens cannot be cheap.
Secondly, the main material for OLED displays - indium tin oxide - is expensive. A kilogram costs about $ 800, and the cost is constantly growing as demand increases.
Thirdly, so far companies have been producing devices with flexible and folding screens in small batches. The smaller the supply, the higher the cost of one device.
Fourth, despite the fact that there are few devices of a new type, huge amounts are invested in their promotion. These funds must be returned, so that they are also part of the price of the device.
What is the complexity of production
Details of the company's production are not disclosed. But the difficulty is not only that you just need to make displays flexible or folding. It also means that it is necessary to look for new materials for the case, think about energy saving (a larger screen consumes a lot of energy) and develop new technological processes.
Samsung also introduced the first flexible OLED screens six years ago . The OLED display itself is a complex and thin structure that cannot be subjected to strong external influences. Such a display is the thinnest film of organic material between the electrodes, which deliver energy to individual pixels. Electricity activates a pixel or turns it off.
The classic OLED matrix in a regular phone cannot be bent without harm to the intermediate layers. When bending, the conductive layer will change its characteristics, and such a screen will not work normally. For the display to continue to work when folded, you need a special filler, a structure that creates something like a flexible frame that holds all the elements in place even during bending.
And this is only part of the problem, since the touch is also an important element of the screen: the touch surface should not lose its properties during deformation.
Plus, as the surface of the display increases, its energy consumption increases, so developers have to look for new ways to increase the energy efficiency of devices. They should not be discharged faster than the modern user is used to. Otherwise, no one will buy new phones.
Why technological product is not popular
One of the main problems is the high cost of devices. It is impossible to solve it right now, because a lot of money has been invested in the technology, and it needs to be returned. And the devices are being released in very small batches.
The second difficulty is the technical imperfection of the devices. This can be judged by what happened Samsung Galaxy Fold. Despite the manufacturer’s assurances that it is possible to bend / unbend the screen thousands of times without harm, the reality turned out to be different. In the very first days, devices that got to the test by techno-media journalists began to break down. The screen spoiled even the dust that got inside, not to mention the mechanical effect on the display. The company promised to solve this problem after Samsung engineers examined the failed phones and realized what was the reason. It is clear that no one will give guarantees that after entering the mass sale there will be no other problems.
The third is the uncertainty of demand. So far, only geek enthusiasts are willing to pay big money for unusual devices, which, moreover, also break down. And if you don’t buy phones, the technology will remain unclaimed. You can solve the problem only by lowering the price, increasing reliability and conducting successful marketing campaigns.
Samsung representatives predict that by 2022 the market for flexible displays will grow at least four times. But in fact, the company voices its own expectations. Having invested several billion dollars in the project, the corporation hopes to recapture them in the future. In reality, he does not know how successful and popular this decision is.