To truly understand these devices, it's not enough to just look at their technical specifications: you need to know how the hinges and screens that allow folding workWe'll explore the different designs being used and the challenges of durability, weight, and protection that brands like Samsung, HONOR, Huawei, and TCL have had to overcome, along with their advantages and disadvantages. We'll delve into all that engineering, but in clear and accessible language, so you can decide if this type of phone is right for you.
What exactly is a foldable phone and what makes it possible?
A foldable mobile phone is, essentially, a high-end smartphone with a foldable screen to offer two experiences: when closed it takes up less space and fits better in your pocket, and when you unfold it approaches the format of a tablet, ideal for watching videos, working with several apps or playing games more comfortably.
These types of mobile phones began arriving in stores around 2019 and, although their use is not yet as widespread as that of traditional smartphones, Forecasts point to strong growth in the coming yearsThe key to their success will be combining a more affordable price with a reliable hinge that can withstand heavy use without loosening or breaking.
The component that makes folding possible is the screen, based on flexible OLED panelsThis OLED technology allows the panel to be curved or bent because it doesn't require a rigid backlight like LCDs. In practice, the screen is made up of several layers: typically up to 12 layers of ultra-thin protective glass or special plastic and two layers of light-emitting organic compoundsThanks to this, thinner, lighter, brighter screens with lower energy consumption are achieved.
A whole support system is built around that flexible screen: the hinge, the frame, the internal reinforcements, and the protective coatingsThe manufacturers' goal is for the user to feel like they are using a solid and robust mobile phone, even though inside there are precision parts capable of bending hundreds of thousands of times and requiring maintenance tips to extend its useful life.
Types of foldable mobile phones and folding methods
Starting from the basic idea of ​​the flexible OLED panel, manufacturers have been experimenting with different folding formats to suit different uses, including models with dual-screen foldablesNot all foldable phones are the same: some focus on maximizing screen space, others on reducing pocket size, and still others explore more futuristic concepts like rollable panels.
Book-style or foldable tablet phones
It is the most recognizable format and the one popularized by models such as the Samsung Galaxy Fold or the HONOR Magic VsIn their closed position, they resemble a slightly thicker-than-normal mobile phone; when opened, they transform into a kind of mini-tablet with a large screen inside. The aim is to offer more space for productivity, multitasking, and content consumption.
In this type of device, the large foldable screen is usually located on the inside, and brands add a smaller screen on the outside to use the phone without opening it. This approach allows for better protection of the flexible panel, as it is not exposed when the phone is folded.
Clamshell or flip-type mobiles
The other major commercial format is the clamshell type, which has been popularized above all by Samsung with the family Galaxy z flipThe priority here isn't so much having a giant screen when it opens, but minimize the space it takes up in your pocketWhen closed, the phone becomes a compact square or rectangle; when open, its size is similar to that of a normal smartphone.
This style recaptures some of the essence of classic flip phones, but with a continuous, flexible internal screen and, typically, a small external screen for notificationsIt's a very attractive format for those who want something different and appreciate being able to leave their phone on the table half-open, without having to put it on any stand.
Mobile phones with rollable screens
They're not mass-market products yet, but some manufacturers like TCL already have them. prototypes of mobile phones with rollable OLED screensInstead of folding on a fixed hinge, the screen extends like a curtain from one side of the device, increasing in size when you need it and returning to its compact format when folded away.
TCL has taught concepts with a square screen that stretches vertically to about 6,7 inches and others with panels up to 17 inches wide that unroll completely and are stored on rear cylinders. This type of design promises to maintain a more uniform thickness, since the rolling process It does not create an extra bulk in the chassisBut it is still in a very early stage.
The hinge: the mechanical heart of a foldable mobile phone
If the flexible screen is the muscle of these phones, the hinge is their true heart. It's the component that allows them to The device opens and closes precisely, without forcing the panel.and that it can also be fixed at different angles. Its design determines the thickness, weight, durability, and even the final shape of the phone.
The first big batch of foldable laptops already made it clear that Not all hinges are the same.Some models fold outwards, with the screen always exposed, while others fold inwards, concealing the flexible panel. There are also differences in how well they close: some devices leave a small wedge-shaped gap when closed, while others achieve a virtually flat closure.
The size of the hinge also influences the design. A complex hinge with many gears can offer very precise rotation, but It adds thickness and weight to the device.That's why we're seeing a clear evolution towards lighter systems, with fewer components, but just as strong.
How Samsung does it: flexible glass, hidden hinge, and Flex mode
Samsung has been one of the brands that has invested most heavily in foldable phones, refining both its screens and hinges generation after generation. It has also worked on improvements related to batteries and sensors which complement their overall focus on hardware. Their most recent models, such as the Galaxy Z Fold 5 or Galaxy Z Flip 5, utilize ultra-thin reinforced glass like Corning Gorilla Victus, an engineered material that combines extreme thinness with very high flexibility.
This glass is integrated on top of the flexible OLED panel to offer a more solid screen feel to the touch, without sacrificing the folding capability. The result is that you can open and close the mobile phone smoothly, without noticing any strange creaking or feeling of fragility every time you bend the device.
At the center of the design is a custom-made high-precision hingeThis allows the phone to be opened and closed with a very controlled movement. Samsung has incorporated a small gap between the two halves when the device is closed: this way, the glass layers don't touch and direct friction between them is avoided, reducing the risk of marks or breakage from pressure.
Furthermore, the hinge is designed so that the phone can stay in place. semi-open at different anglesThis allows you to use Flex mode: propping your phone up on a surface like a mini laptop or stand, which is very useful for selfies, video calls, or recording vlogs without a tripod. It's one of the features that truly makes the most of the foldable design in everyday use.
The hidden hinge of the Galaxy Z Flip: dual CAM mechanism
In the specific case of the Galaxy Z Flip, Samsung developed a Hideaway HingeAt first glance, the mechanism is barely noticeable because it's integrated into the chassis, but it's a true feat of engineering. One of its key elements is the dual CAM system, shaped like a ridge.
This dual CAM mechanism provides a gradual and stable foldingInstead of simply opening or closing the phone like a two-position light switch, it allows the device to lock into several intermediate angles. It's like going from a simple switch to a dimmer: you have more control over how you position the screen.
At the same time, the precise design of this mechanism keeps the hinge hidden and compact, so that The Galaxy Z Flip is still small enough to fit in the palm of your hand and in tight pockets, without sacrificing the feeling of solidity when handling it.
Sweeper Technology: fibers to keep the hinge clean
One of the biggest enemies of any folding hinge is dirt. Dust, sand, or small particles can get trapped inside. microscopic gaps between the body and the hinge and end up damaging the mechanism or the screen. This risk is even greater in foldable phones because there are more entry points than in a traditional rigid phone.
To address this problem, Samsung devised the Sweeper technologyIt's a kind of internal barrier made of nylon fibers cut to a micrometer height. These fibers act like a small, flexible brush that adapts to the hinge's movements and helps repel dust and dirt before they reach sensitive areas.
The development of this system was not immediate: the engineers had to test dozens of prototypes until they found the right combination of elasticity, durability, and thinness. The final solution was inspired by the fibers used in vacuum cleaners, which also need to maintain their flexibility long-term to continue functioning properly.
The result is that the hinge can withstand up to 200.000 folds in testingIt keeps dust at bay and maintains the same smooth movement even after years of theoretical use. This equates to several years of opening and closing the phone dozens of times a day without the mechanism starting to fail.
HONOR Magic Vs: Super-lightweight, gearless hinge
HONOR has followed its own path with its foldable Magic Vs, focusing on a hinge that seeks to solve several of the common drawbacks of these devices: heavy weight, considerable thickness, and internal complexityTo achieve this, it has developed a super-lightweight, gearless hinge, a pioneer in the industry.
In many traditional folding phones, gears are used to ensure smooth and controlled screen rotation, but They increase the number of parts, the weight, and the volume of the mechanismHONOR has opted to eliminate those gears and reduce the support structure to a minimum, going from 92 components in the hinge of its previous model (HONOR Magic V) to only 4 in the Magic Vs.
This drastic reduction in parts allows the hinge to be much lighter and simpler, without sacrificing a stable and well-guided rotationFurthermore, thanks to its design, the device achieves a more complete screen closure, like a fully closed book, reducing the typical central gap left by other models and improving the visual and tactile experience.
The extra space freed up by the compact hinge has been used to include a 5.000 mAh batteryThis is especially valuable in a foldable phone, as the large internal screen tends to consume more power. This achieves a better balance between sleek design and actual battery life.
Aerospace-grade materials to reduce weight and increase durability
Another secret of the HONOR Magic Vs is the material used in its hinge, a special aerospace-grade polymerThis material is 62% lighter than the metals commonly used in this type of mechanism, which contributes to significantly lightening the overall assembly.
Thanks to this approach, HONOR's foldable smartphone has It is approximately 12,9 mm thick when folded and weighs approximately 267 grams.It may still be heavier than many traditional mobile phones, but it is in a very competitive position within the foldable segment, as this polymer material is up to 34% lighter than the aluminum alloy used by many rivals.
The choice of this polymer also comes with a clear focus on durability. HONOR states that the hinge is designed to withstand more than 400.000 foldsThis, translated into real-world use, would be equivalent to more than ten years of bending the phone around 100 times a day. This figure aims to allay the common concern that these devices "will break in four days."
Working with these types of materials is not trivial: aerospace-grade polymer It requires very precise manufacturing processesTo adapt, HONOR redesigned the molds and improved the machinery, adding systems such as the hot runner and optimized cooling so that the material would be molded correctly without losing its mechanical properties.
Tablet-type internal screen and user experience
At the screen level, the HONOR Magic Vs incorporates a 7,9-inch flexible OLED panel Inside, it boasts a 90Hz refresh rate and 100% color space coverage (according to the manufacturer). Its approach is clear: to offer an experience very close to that of a tablet, but without sacrificing the mobile format when folded.
The difference between the complete screen closure and the space left by the hinge It also influences the perceived quality and robustness of the device. The Magic Vs aims for the two halves to be perfectly aligned, without visible gaps, and with a compact, block-like feel, reinforcing the idea that it is a solid and well-assembled product.
Samsung Galaxy Fold and Huawei Mate X: two hinge philosophies
The first major benchmarks in the modern era of folding books were the Samsung Galaxy Fold and Huawei Mate XBoth models demonstrated what could be done with a flexible screen, but they also made it clear that the way the hinge and folding mechanism are designed completely defines the type of device you get.
In the case of the Galaxy Fold, Samsung opted for a hinge that fold the screen inwardsThis way, the main flexible panel is protected inside when you close the phone. To maintain functionality without having to open it every time, a smaller external screen (4,6 inches in the first generations) and an external and internal camera system were added, which considerably complicated the design.
The great advantage of this approach is protection: having the folding screen inside greatly reduces its exposure to bumps, scratches, and contact with keys, coins, or other objects. This is an important point because the internal flexible layers They do not have the typical traditional rigid Gorilla Glassbut with more delicate, specific solutions.
Huawei, on the other hand, took the opposite approach with its Mate X. In this model, the The screen folds outwards and is always exposed.There is only one large screen which, when folded, is divided into a front of about 6,6 inches and a rear of about 6,38 inches, which can be activated depending on the use you want to give it.
This solution is conceptually simpler and, most likely, cheaper to manufacture than the complex Galaxy Fold systemSince there's no need to duplicate screens or cameras, it sacrifices robustness: whether the phone is folded or unfolded, it's always "all screen," and any scratch or bump can mark the surface if you're not careful.
To mitigate this risk, Huawei designed specific cases that protect most of the device without preventing folding. Even so, the user has to be more careful when storing the phone in bags or backpacks, since the active surface is exposed almost all the time.
Between these two proposals, other experiments emerged, such as the FlexPai, whose design left the phone wedge-shaped when closed, with a visible gap near the hinge. Although it was a pioneer, It was not convincing in terms of ergonomics or ease of useand helped the industry better understand how complicated it is to find the perfect balance between idea, hinge, and software.
Key features that take advantage of foldable hinges and screens
Beyond the "wow" effect of opening and closing the phone, foldable phones stand out for a number of reasons. features that take advantage of its hybrid formatIt's not just about having a bigger screen, but about integrating hardware with software for a more versatile experience.
Flex mode and integrated support
Flex mode, popularized by Samsung, allows the mobile phone detect when it is partially folded and rearrange the interface accordingly. For example, in apps like YouTube, you can watch the video in the top half and view the controls or comments in the bottom half, while the device remains stable on the table without needing external support.
This same concept applies to video calls, selfies, or vlog recordingsThe bottom of the phone acts as a stand and the top as the screen, like having a built-in mini tripod. It's one of those things that seems like a minor detail until you get used to leaving your phone propped up anywhere while you're on a call or watching a show while cooking.
True multitasking on a big screen
Another advantage of these devices is the possibility of work with multiple applications at the same time comfortablyThanks to the large internal screens, you can divide the panel into two or more zones and have a document open on one side, email on another, and perhaps a video in a floating window.
Features like multi-window or picture-in-picture mode make much more sense than on a conventional mobile phone, because You don't sacrifice as much content area by splitting the screenThis makes book-style foldable phones especially interesting tools for those who use their mobile phone as a portable work center.
Copy, paste, and drag between apps
Copying and pasting text is already possible on a regular mobile phone, but the experience can sometimes be awkward due to the small size. A foldable phone with a large screen offers greater precision and a larger screen area, and also... the possibility of having two applications side by side It makes dragging content from one to another much more natural.
You can, for example, drag text containing a discount code from your browser to a notes appMoving a photo directly to a messaging chat or copying a phone number without having to jump from one app to another in full screen are details that add up for those who work a lot from their mobile phone.
Durability, myths and certifications of foldable phones
As it is a relatively new technology, it is logical that there are some mistrust regarding long-term durability and reliability of foldable phones. Brands are aware of this and have been refining materials, mechanisms, and testing processes to demonstrate that they can withstand the demands of daily use.
In recent models, some manufacturers use reinforced aluminum frames and glass such as Gorilla Glass Victus On the exterior, combined with special protective layers on the flexible screen, this reduces scratches and improves drop resistance, although using a case is always recommended, as with any high-end mobile phone.
Regarding the number of folds, both Samsung and HONOR perform laboratory tests of hundreds of thousands of openings and closingsThe Galaxy Z series, for example, has been tested for 200.000 folds, while the HONOR Magic Vs boasts up to 400.000 without failure. These figures equate to several years of intensive use, opening and closing the phone many times a day.
Another aspect that has improved over time is water resistance. Some foldable models now feature... IPX8 certificationThis means they can be submerged in fresh water up to 1,5 meters deep for up to 30 minutes under laboratory conditions. While they will still be products that require care, they are no longer as fragile as the first experimental models on the market.
The hinge has also been better sealed and protected. Technologies such as Samsung's Sweeper repels dirt that could enter through the slots, and the structure itself is designed to convey a pleasant and consistent tactile feel throughout the device's life cycle, without premature looseness.
Foldable phones have gone from being almost prototypes for collectors to becoming real options for those looking for something differentWith increasingly thinner and more reliable hinges, highly advanced flexible OLED screens, and software features that truly take advantage of the format, whether for productivity, entertainment, or simply convenience when placing them on any surface.
