A foldable is exactly that — a folding phone. Unlike bar-type smartphones with a single body, foldables consist of a central hinge and two folding sides. The hinge serves as the central axis for opening and closing the phone. Over time, Samsung has introduced unique, cutting-edge technology into the hinge mechanism of its Galaxy Z Fold series to create a revolutionary hinge design with each release. In addition, Samsung has continued to reduce the thickness of the Galaxy Z Fold series so the phone can be carried anytime, anywhere.

Samsung Newsroom looked back at the evolution of the Galaxy Z Fold series’ sleek profile and distinctive hinge design — now thinner, sturdier and compact as ever.

[2019] Galaxy Fold

The Dawn of Foldable Phones: Folding and Unfolding

Thickness when folded: 15.7-17.1mm Thickness when unfolded: 6.9-7.6mm Weight: 276g

As user lifestyles continue to diversify, so too do their needs. Samsung has consistently introduced advanced technologies each year to meet these changes. First unveiled in 2019, the Galaxy Fold featured a groundbreaking form factor — the first to deliver a natural, big-screen experience when unfolded and a compact, portable experience when folded. The act of “folding and unfolding” emerged as a new category of mobile interaction, and Samsung applied never-before-seen hinge technology to ensure this functionality felt natural and intuitive.

The inward-folding hinge not only felt familiar and easy to use, but it also provided robust display protection. The phone could be smoothly opened like a book, yet stay flat and thin when folded. The palm-sized dimensions were key to its convenience. With the first Galaxy Fold, Samsung achieved a maximum folded thickness of just 17.1 millimeters and ushered in the era of smart foldables.

[2020] Galaxy Z Fold2

The Era of Flex Mode: Hideaway Hinge and Sweeper Technology

Thickness when folded: 13.8-16.8mm Thickness when unfolded: 6.0-6.9mm Weight: 282g

In 2020, the successor to the pioneering Galaxy Fold was released. The Galaxy Z Fold2 took foldables to the next level with an all-new sophisticated and refined design. The most notable of its several innovative features was the Hideaway Hinge, which seamlessly connected the body of the smartphone while supporting stable folding and unfolding. Users could mount the Galaxy Z Fold2 at various angles with the Hideaway Hinge to easily take selfies and make video calls in Flex Mode.

The Hideaway Hinge’s more than sixty parts made the innovative dual CAM mechanism a reality. The flat surface between two ridge-shaped parts, CAM helped keep the device open or closed and enabled Flex Mode. By increasing the number of CAM structures and springs, the hinge could reliably support wider angles. The Hideaway Hinge was mounted on an optimal location on the Galaxy Z Fold2 for an even slimmer design and a maximum folded thickness of just 16.8 millimeters.

Since the hinge was constantly folded when the device was opened or closed, there was an inevitable gap between the front of the device and the hinge housing. To effectively minimize this gap, Samsung needed to develop a component that would be long-lasting and elastic without adding extra bulk. Inspired by the brush of a vacuum cleaner, Samsung made use of delicately cut optical fibers to address this issue: Sweeper Technology. Sweeper Technology protected the phone’s display from external dust and debris that could enter through the gap , providing a more fluid foldable device experience.

[2021] Galaxy Z Fold3

The Solution to the Foldable Phone’s Biggest Challenge: Waterproofing

Thickness when folded: 14.4-16.0mm Thickness when unfolded: 6.4mm Weight: 271g

It’s a given that today’s smartphones are waterproof. However, the hinge that opened and closed the screen on foldables would always be exposed to the elements. If liquids such as beverages or even rainwater leaked inside, the device would be at risk of immediate malfunction.

The Galaxy Z Fold3 was the first foldable to be water resistant, one of the biggest challenges that previous foldable devices faced. Samsung’s waterproofing technology was applied to two areas — the outer part of the display and the hinge. The outer part of the display was surrounded by a rubber band that prevented dust and liquid from entering, whereas the metal parts of the hinge were made of corrosion-resistant materials and coated with a long-lasting lubricant. The terminal connecting the two mainboards bordering the hinge was sealed with a silicone-based cured-in-place gasket (CIPG) that prevented liquid from entering the device. Additionally, flexible printed circuit board (FPCB) cables were used to protect sensitive components.

A robust material that withstands external shocks and reduces the risk of deformities or scratches, Armor Aluminum was used to help the Galaxy Z Fold3 achieve an even thinner and lighter form factor.

Armor Aluminum was applied to the two edges that make up the exterior and to the housing that surrounds the hinge. Various components were densely packed inside the Galaxy Z Fold3’s Hideaway Hinge to enable Flex Mode and ensure smooth opening and closing. To support these functions, the hinge housing needed to be made from sturdy materials.

The Sweeper Technology that closed the gap between the hinge and the body of the foldable evolved too. As the device became slimmer, the sweeper’s bristles were shortened to improve aesthetics while still keeping the hinge safe from dust and external particles. These innovations allowed the Galaxy Z Fold3 to be as thin as 16.0 millimeters when folded.

[2022] Galaxy Z Fold4

From Rotating to Linear: A Slimmer, Lighter Hinge

Thickness when folded: 14.2-15.8mm Thickness when unfolded: 6.3mm Weight: 263g

Unveiled in 2022, the Galaxy Z Fold4 saw a significant reduction in weight and thickness. At 263 grams, the device weighed nearly 20 grams less than the Galaxy Z Fold2 at 282 grams. The maximum folded thickness was 15.8 millimeters, making this foldable the thinnest in the series at the time. Once again, Samsung loaded its signature foldable with innovation — resulting in an easy-to-grip, thin and lightweight body.

Redesigned to be 21% lighter than its predecessor, the new hinge of the Galaxy Z Fold4 accommodated the wider width and shorter length of the Cover Screen. While the previous foldable in the series used interlocking gears to ensure even screen folding and unfolding, the Galaxy Z Fold4 changed the hinge motion from rotary to linear. This adjustment drastically reduced weight, thickness and the number of parts, which streamlined manufacturing and improved the device’s resilience. With the Galaxy Z Fold4, Samsung built its slimmest, lightest hinge at the time while upholding the same level of durability as the previous form factor.

[2023] Galaxy Z Fold5

Flex Hinge: The Secret to a Fully Foldable Phone

Thickness when folded: 13.4mm Thickness when unfolded: 6.1mm Weight: 253g

In 2023, the Galaxy Z Fold5 introduced the world to the next generation of foldable smartphones. Moving away from the traditional Hideaway Hinge, Samsung unveiled a new type of mechanism called the Flex Hinge — demonstrating a leap forward in foldable innovation. With improved flexibility and a wide range of features, the Flex Hinge made it possible for the display to curl into the hinge like a water droplet using four drive shafts and a dual rail structure that allowed parts to glide along it. Thanks to this hinge technology, the two screens could be evenly folded without any creases or gaps.

This new folding mechanism resulted in the lightest and thinnest Galaxy Z Fold series device yet. More than two millimeters thinner than its predecessor, the Galaxy Z Fold5’s maximum thickness is 13.4 millimeters when folded. The foldable also weighs 253 grams — 10 grams lighter than its predecessor — making it more compact, portable and stable when folded. The phone’s sleek, solid shape could be appreciated from any angle.

Each year, Samsung refines the Galaxy Z Fold series by leveraging precise engineering and meticulous manufacturing processes. Every detail is studied carefully, from internal mechanisms to exterior design. Reimagining the hinges and device thickness — core attributes of the foldable — has enhanced the utility of the Galaxy Z Fold series immensely. Samsung will continue to build on its legacy of unprecedented foldables, ensuring that more people can utilize them for an even more convenient life.

Discover the next generation of Samsung’s innovations at Galaxy Unpacked 2024 on July 10 in Paris.

Versatile, compact and stylish, the Galaxy Z Flip is made for fast-paced, modern lifestyles and for those who aren’t afraid to make a statement. Built to inspire creativity, the device packs everything you need for content creation and sharing into a form factor that fits in the palm of your hand.

Flex Your Creativity

The Galaxy Z Flip’s unique form factor is designed to provide hands-free experiences, making it easy for you to create content no matter where you are.

Thanks to its Hideaway Hinge, the device can stand on its own at various angles. Simply pop open the device, place it on a desk or on the floor, and you can start filming your latest dance challenge video without extra accessories or stands.

With Flex mode, you can easily snap hands-free selfies for your social media feeds or capture steady, stunning Night Hyperlapse videos with just the Galaxy Z Flip. The feature also lets you easily set up live streams to connect with your followers or instantly collaborate with other creators via video call.

Capture the World Differently

From spontaneous selfies to hilarious GIFs of funny moments, the Galaxy Z Flip gives you new ways to capture your experiences.

The Quick selfie feature uses the device’s powerful rear cameras to create high-quality self-portraits. Double click the power button when the phone is folded and the cover display will transform into a selfie viewfinder. You can then click the volume button to capture a shot. If you are taking a groupie with your friends, you can tap on the cover display to switch to the Ultra Wide lens.

With so many ways to create photos and videos, it can sometimes be difficult to decide which one to go for in the moment.

Single Take on the Galaxy Z Flip is a dream tool for digital creators. The feature is especially useful for shooting action-packed scenes.

Just hold down the shutter button and the camera will capture the moment in a wide range of formats. What’s more, the feature even recommends the best shots, which means you don’t need to scroll through your gallery to find the perfect post.

Elevate Your Content

Ask any digital creator and they will tell you that taking photos and videos is just the start of the creative process. From image editing to caption writing, there are many steps when it comes to producing engaging content.

Equipped with quick and easy image editing tools, the Galaxy Z Flip is a mobile creative powerhouse. As soon as you take a shot, you can start polishing your image, try out different filters, and put your next post together on the device. The Multi-Active Window feature also allows you to run two apps simultaneously on the main display. With the ability to edit photos on the top half of the display while writing captions or responding to comments on the bottom half, you can multitask and manage your platform on the go with ease.

Fashion Meets Technology

Featuring a bold and playful design, the Galaxy Z Flip is perfect for those who see technology as a way to express themselves. Available in various luxurious color options, including Mirror Purple, Mirror Black, and Mirror Gold for the Galaxy Z Flip, the device will turn heads and bring individuality to your outfit.¹

¹ Color availability may vary depending on country or carrier.

In this second installment of a two-part series on the Galaxy Z Flip’s Hideaway Hinge, we will take a look at another key innovation, which helps to protect the device from dust and dirt – the sweeper technology.

Sweeper Technology

In designing the Galaxy Z Flip’s hinge, Samsung engineers not only had to account for the spaces between the body and the hinge, but also meet three specific conditions: Elasticity (to account for shifts in the gap size); long-lasting flexibility (the hinge is tested to withstand 200,000 folds¹); and slimness (to keep the device’s sleek form factor).

Finding a solution that protected against particles and met those conditions meant dozens and dozens of failed prototypes. But then, one of Samsung’s top engineers noticed that the way fibers were used in vacuum cleaners was similar to what was required for the Hideaway Hinge. The sweeper fibers were not only pliable enough to cover all the gaps as the smartphone folds and unfolds, they also remained flexible after long-term usage.

Now let’s take a look at how Samsung engineers overcame all those challenges and what the outcome of their efforts looks like.

¹ 200K folds based on internal testing conducted by Samsung, results may vary.