Samsung reviews the development process of the “Galaxy Z Fold” series of phones

Written By Mark

Samsung developed a unique and advanced hinge mechanism for the Galaxy Z Fold series, creating a revolutionary hinge design with each new release. Samsung has also continued to reduce the thickness of the Galaxy Z Fold series so that the phone can be easily held anywhere, anytime.
The Samsung Newsroom highlighted the remarkable development in the elegant side appearance of the Galaxy Z Fold series of phones, as well as the distinctive hinge design that is now thinner, sturdier and smaller than ever before.

(2019) Galaxy Fold: Innovation in foldable phones: folding and unfolding, folded thickness: 15.7-17.1 mm unfolded thickness: 6.9-7.6 mm Weight: 276 g

As lifestyles continue to diversify among users, their needs have also diversified and changed over the years. Hence, Samsung has been keen to continuously introduce advanced technological innovations every year to meet these rapid changes. The unveiling of the Galaxy Fold in 2019 was a pivotal moment, as Samsung introduced an innovative design that provided a wide and natural screen experience when opened, and a compact portable experience when folded. In doing so, the “fold and unfold” feature emerged as a new and distinctive feature in the world of smartphones. Samsung was keen to implement a distinctive hinge technology, to ensure that this feature is smooth and easy for the user.

The inward-folding hinge was not only a familiar and intuitive feature, but also provided robust screen protection. Thanks to the innovative design, the phone opens smoothly like a book, and remains flat and light when folded, while the palm-sized dimensions contribute to maximum comfort. In fact, Samsung achieved a maximum folded thickness of just 17.1mm with the first Galaxy Fold, paving the way for compact and portable foldable smartphones.

(2020) Galaxy Z Fold2, Flex Mode Era: Hidden Hinge and Sweeper Technology, Folded Thickness: 13.8-16.8mm, Open Thickness: 6.0-6.9mm, Weight: 282g.

In 2020, Samsung launched the Galaxy Z Fold2 as an advanced successor to the original foldable device, the Galaxy Fold. This new phone has taken foldable design to a new level, thanks to its innovative features. One of the most prominent of these features was the “Hideaway Hinge”, which is an advanced hinge that seamlessly connects the body of the smartphone and supports the folding and unfolding process in a stable manner. This unique design allows users to bend the phone at different angles, making it easier to take selfies and make video calls in Flex Mode.

The hinge features a flat surface between its two halves, which helps keep the device open or closed securely, as well as enabling Flex Mode. By increasing the number of CAM structures and springs, the hinge is now able to reliably support wider folding and unfolding angles. This hidden hinge is ideally placed on the Galaxy Z Fold2, enabling a slimmer design, with a maximum thickness when folded at just 16.8mm.

Because the hinge constantly folds when the device is opened or closed, there is inevitably a gap between the front of the device and the hinge housing. To effectively reduce this gap, Samsung had to develop a long-lasting component.

And flexible without adding bulk. Inspired by the vacuum cleaner brush, Samsung used finely chopped optical fibers to address this problem, which it calls “Sweeper” technology.

“Sweeper” technology protects the phone screen from dust and external impurities that may leak through that gap, providing a smoother user experience for the foldable device.

(2021) Galaxy Z Fold3, the solution to the biggest challenge facing the foldable phone: water resistance, Folded thickness: 14.4-16.0 mm Open thickness: 6.4 mm Weight: 271 g.

Although most smartphones are now water-resistant, the hinge that allows the screen of foldable devices to fold and unfold will always be exposed to the elements. If liquids such as drinks or rainwater seep into the device through that hinge, the device is at risk of immediate failure.

The Galaxy Z Fold3 was the first foldable phone to have effective water resistance, which is one of the biggest challenges that previous foldable devices have faced. Samsung applied advanced waterproofing technology to two important areas – the outer part of the screen and the hinge itself. The outer part of the screen is surrounded by a rubber band that prevents dust and liquids from entering, while the metal parts of the hinge are made of corrosion-resistant materials and coated with high-quality lubricants. The end connecting the two main panels at the hinge has also been sealed with a CIPG-treated silicone gasket and locked in place to prevent fluid ingress. Finally, flexible printed circuit board (FPCB) cables are used to protect sensitive components.

In addition, Armor Aluminum, a strong and durable material, was used in the manufacturing of the Galaxy Z Fold3 to help it achieve a thinner and lighter frame. This material is characterized by its ability to resist external shocks and significantly reduces the risk of deformations or scratches to which foldable devices may be exposed.

Armor Aluminum is applied to the two ends that form the outer part, as well as the casing surrounding the hinge of the Galaxy Z Fold3. Several components are densely integrated into the Hideaway Hinge to enable Flex Mode and ensure smooth opening and closing. To support these functions, it was necessary for the hinge housing to be made of highly durable materials.

Additionally, the Sweeper technology was developed to close the gap between the hinge and the foldable body. As the device shrinks, the slits of this technology are shortened to improve aesthetics while keeping the hinge safe from dust and foreign particles. These innovations have enabled the Galaxy Z Fold3 to be just 16.0mm thick when folded.

(2022) Galaxy Z Fold4, from rotary to linear motion: a thinner and lighter hinge, Folded thickness: 14.2-15.8mm, Opened thickness: 6.3mm, Weight: 263g

The Galaxy Z Fold4 was unveiled in 2022, and saw a significant reduction in weight and thickness, weighing in at 263 grams, about 20 grams less than the Galaxy Z Fold2’s 282 grams. The maximum folded thickness of the device was 15.8mm, making it the thinnest in the series at the time. Here, Samsung continued to enhance its premium foldable phone with more innovative developments, resulting in a slim, easy-to-use and lightweight design.

The Galaxy Z Fold4 has been redesigned to be 21 percent lighter than its predecessor, with a new hinge accommodating the wider width and shorter length of the outer display. While the previous foldable model in the series used interlocking gears to ensure the display folded and unfolded evenly, Samsung changed the hinge’s motion from rotary to linear for the Galaxy Z Fold4. This change significantly reduced weight, thickness, and component count, enhancing the manufacturing process and increasing the device’s flexibility. As a result,

Samsung built the thinnest and lightest hinge at the time while maintaining the same level of durability as the previous model.

(2023) Galaxy Z Fold5, Flexible Hinge: The secret to a fully foldable phone, Folded thickness: 13.4 mm Open thickness: 6.1 mm Weight: 253 g.

In 2023, Samsung introduced the Galaxy Z Fold5, the next generation of foldable smartphones. Moving away from the traditional hinge design, the company unveiled a new mechanism called the Flex Hinge, representing a leap forward in foldable innovation. With improved flexibility and a wide range of features, the Flex Hinge allows the display to curl inside the hinge like a drop of water, using four actuating pillars and a dual barrier structure that allows parts to slide along it. As a result, both displays can be folded evenly without any wrinkles or gaps.

This new foldable design results in the lightest and thinnest Galaxy Z Fold yet. The device is more than 2mm thinner than its predecessor, with the Galaxy Z Fold5 reaching a maximum thickness of 13.4mm when folded. The foldable device also weighs just 253 grams — 10 grams lighter than its predecessor, making it easier to hold, more stable when folded, and more beautiful to look at as well.

Every year, Samsung continues to improve the Galaxy Z Fold series by leveraging precision engineering and advanced manufacturing processes. Every detail is carefully considered, from the internal mechanisms to the exterior design. Reimagining the hinges and device thickness – the core features of foldable devices – has significantly enhanced the Galaxy Z Fold series. Samsung will continue to build on its rich legacy of innovative foldable devices, ensuring that more people can take advantage of this technology to bring added convenience to their everyday lives.

Samsung is scheduled to unveil the next generation of its innovations during the “Galaxy Unpacked” event scheduled to be held in Paris on July 10, 2024.