How Oppo Built The Bestlooking, And Perhaps Most Durable, Hinge In Foldables

© Contributed by XDA Developers

Oppo, late to the foldable phone market after Samsung, Huawei, Xiaomi, Motorola and Royole, has quickly released three foldable phones in the last 15 months. All three received rave reviews for their looks, cost, and performance. But the area that's received the most praise from across the consumer tech space is the hinges, which fold completely flat with no gaps, leave no hard creases on the screen, and articulate fully. No other foldable phone can claim all of this right now.

What if this complex mechanism, which Oppo calls a “flexible hinge”, was not only the most beautiful, but also the most durable on the market? This is what Oppo claims about the hinge of the recently released Find N2 Flip, which has been tested to withstand at least 400,000 bends - double what Samsung claims about the Z Flip 4. Even if you open your phone 100 times a day, it will need almost 11 years to get there.

But how true is this statement? Obviously, I don't have the time or energy to manually fold and open the Find N2 Flip 400,000 times, and YouTuber JerryRig is still testing the famous Find N2 Flip (he first tested the Find N and praised the hinge's durability). I think the best thing I can do next is to tell you about my similar experience and talk to the German 3rd party technology validation team TUV Rheinland, who have independently tested the Find N2 Flip.

Four test levels TUV Rheinland

During a video call with Jay Yang, VP of TUV Rheinland Electrical, Yang said his company tested the Oppo Find N2 Flip in four areas: folding and unfolding; withstand extreme temperatures; prevent the ingress of foreign bodies; And two types of drop tests.

“We spent over 1,100 hours testing [Find N2 Flip],” Yang said. “But getting the raw number was not the goal. We wanted to test the phone on different occasions and conditions to simulate real-world usage."

This means that TUV Rheinland didn't just fold and unfold the phone at the same angle over and over for testing. He bent the phone to its original angle and ran the test in an air-conditioned room at temperatures ranging from 167 degrees Fahrenheit (or 75 degrees Celsius) to minus 4 degrees Fahrenheit (minus 20 degrees Celsius).

Maintaining 400,000 folds without damaging the screen is impressive, but what impressed Yang even more was that it took more than 216,000 folds before the previously weak fold became unnoticeable.

“The bendable nature of the screen means that over time, after many bends, the creases will become more visible and the screen won’t open the way it used to,” he said. “Therefore, in the bend test, we stopped testing screens at different points like 36,000, 72,000, etc. ... Our test equipment noticed [differences in screen curvature] only up to 216,000. Then I will say that the difference is not visible to the human eye, only our equipment. ".

For the UFO penetration test, TUV Rheinland used the old school method. He put the Find N2 Flip (folded) in his wallet with strange items like coins, credit cards, eyeliners and sand. Then use the machine to shake the wallet. Even foreign objects cannot get into the folded screen space.

Finally, there was a drop test. It not only drops the phone on the ground, but also drops objects on the phone screen. Yang said the TUV Rheinland test involved dropping the Find N2 Flip from a height of 1.2 meters with the screen open at various angles onto a marble floor. They then threw a 0.24 lb (110 g) ball at the screen from a distance of 3.6 feet and the screen remained intact.

Yang points out that not all high-end phones can pass these tests. "I've definitely seen failures." However, I couldn't get him to mention phones.

What has Oppo done to make the Find N2 Flip durable?

So how did Oppo manage to create a flip that passed so many TUV Rheinland tests? Oppo senior product manager Elon Lee told me that Oppo has spent a lot of time and money building high-end devices. Despite being late with a single launch, Oppo has been working on foldable phones since 2015 and holds over 400 patents for hinge design and construction.

The latest "Flexion Hinge" used in the Oppo Find N2 Flip as well as its big brother Find N2 has fewer moving parts and engineers are hard at work improving the hinge design. While Oppo hasn't released any images comparing the new Flexion hinge to the old one, YouTuber Michael Fisher has released a very informative video on Oppo's hinge design, showing a significant reduction in size and moving parts.

“For screen durability, we designed a custom stainless steel plate [which required over 10 prototypes] to support flexible soft OLED panels. The plate uses a blind groove design to reduce assembly pressure,” Li said.

The hinge is made from "aircraft-grade aluminum" for strength and lightness, and "rubber dust seals" are placed on the outside to keep out debris.

This is a very technical hardware design that has passed me, and probably most consumers, by the way. I can only use real facts and consensus among reviewers and consumers. As I said, I have tested three Oppo foldable devices and they are all still in good condition. My Find N2 Flip has been a minor phone for a few months and the hinge seems to be pretty solid. Compared to other foldable devices, the Find N2 Flip's design and flat screen easily outperform foldable devices from Samsung, Xiaomi and Honor. My fellow reviewers share similar anecdotal points.

But there is an elephant in the room that we need to take care of.

Why is there no IP rating?

There was a question I had to ask Lee: If durability is the Find N2 Flip's main selling point, why didn't Oppo make the device waterproof like Samsung did?

It turns out the Find N2 Flip is technically IPX4 waterproof, which means it can withstand water splashes from all directions. Oppo simply didn't pay the licensing fees required to get the official IP rating. I suspect Oppo played a role in selling the Find N2 Flip at a lower price. But for all intents and purposes, the phone is IPX4 rated and has waterproof parts inside.

But the Galaxy Z Flip 4 is still more water resistant with an official IPX8 rating. He acknowledges that Oppo could do better here. He says the company looked into this but decided to use a larger battery.

“Currently, the Find N2 Flip has a 4,300mAh battery, which is much larger than other foldable devices on the market,” Li says. “If we added an IPX8 waterproof level, that would mean less space for the battery. We preferred one to the other.

But Lee promises that Oppo is working to provide consumers with larger batteries and an IPX8 rating. In fact, he says it should be in Oppo's next foldable smartphone.

Addresses most early build complaints

I have been seriously obsessed with foldable phones since day one, to the point where I paid more than market value to import Samsung Galaxy Fold and Huawei Mate X stock hardware. Test submitted. For most mainstream consumers, their initial concerns about foldable phones were legitimate: foldables were expensive, bulky, and fragile.

The key word was "was". Prices for high-end devices, at least Chinese ones, have fallen to the same level as regular phones. Some of them are now incredibly thin, a little thicker than an iPhone in the box. And with brands like Oppo struggling to create and design, foldable devices are becoming more powerful than they have a right to be.

Since 2019, foldable phones have been called the "mobile future". In 2023, I think it's time to change that: foldable phones are all the rage.

Oppo Find N2 Flip

Oppo Find N2 Flip is a foldable case with a powerful main camera and a larger external display than the Samsung Flip 4.

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