Who could have guessed that Samsung’s Galaxy Fold would be such a fragile PR nightmare? The iFixit folks who take apart and investigate mobile devices for a living, that’s who.

We’ve watched as Galaxy Fold review units broke for The Verge, CNBC, Bloomberg, Wall Street Journal, and YouTube reviewer Marques Brownlee, each in interesting ways. And while it’s a new device, maybe even an all-new category, there’s still some aspects of the Fold’s brutal first act that we recognize.

I spoke with iFixit’s Lead Teardown Engineer Sam Lionheart about the Fold and the broken units we’d seen glimpses of thus far. I also talked with Dieter Bohn of The Verge about his experiences with his broken review unit. We all pondered some potential problems with Samsung’s nearly $2,000 potential trendsetter. What follows are guesses at how the Fold is failing―informed guesses, based on more than a decade of examining the guts of similar devices, but guesses nonetheless.

First Off: OLED Screens Are Really Fragile

Removing the OLED display on the Samsung S6 EdgeSamsung is the world’s leading maker of OLED displays, both by experience and market share. It makes the OLED displays for the iPhone X series, its own Galaxy phones, and about 89 percent of the world’s AMOLED displays as of 2017. OLED displays have many advantages over more typical LCD displays: they work without backlights, they’re more power efficient, they can create brilliant colors. Most importantly, they’re the only kind of display that you can use in this kind of folding, hinged phablet.

But OLED screens are also far more delicate than LCDs, and prone to complete screen failure rather than localized damage. Any small crack in the encapsulation layer around the OLED layer can fatally damage the organic materials inside the display. As industry-watching site OLED-info notes, “OLEDS are very sensitive to oxygen and moisture and so the encapsulation layer is critical.” You get a sense of their brittleness from seeing repair techs and enthusiasts talk about OLED fixes on Reddit.

The edges of OLED displays, in particular, are something Lionheart and other iFixit techs find challenging to disassemble or repair without damage. “We’ve definitely damaged those displays more when tearing them down, especially when curved,” Lionheart said. “It’s really easy to separate the OLED from the glass, and once that happens, that’s usually it for the screen.” Curved displays are particularly tough to fix, as shown in our Samsung Galaxy S6 Edge teardown.

OLED displays are like tiny, extremely thin cleanrooms you carry around, and any intrusion or stress on them is likely to kill their delicately balanced work. You might be able to see where we’re going with this.

OLED Plus Particles Equals Death

Dust particles in the Samsung Galaxy Fold hingeKnowing how OLEDs react to prying, moisture, oxygen, or nearly anything, it’s plain to see—from reviewers’ photos alone—that the Fold is literally inviting trouble into its fragile innards.

In pictures posted in The Verge’s hands-on impressions (before their Fold review unit broke), you can clearly see gaps at the top and bottom of the hinge when the full screen is open. A close-up of the hinge on its side, with accumulated pocket detritus, makes it even clearer. And the back of the Fold, even with the hinge closed or partially open, doesn’t look airtight.

Back hinge on the Samsung Galaxy Fold“These are some of the biggest ingress points I’ve seen on a modern phone,” Lionheart said. “Unless there’s some kind of magic membrane in there, dust will absolutely get in the back.” It’s important to note, too, that Samsung has offered no IP rating for the Fold.

Bohn finds it baffling the way his Fold unit broke. Especially because the first time he saw a “bump” under the Fold screen was late one night. After consulting with Samsung, he closed the phone and put it aside until the morning. The next day, examining the phone, Bohn saw two bumps under the screen.

Two bumps showing in the crease of the Samsung Galaxy Fold“It seems odd to me that it appeared where it did,” Bohn said. “It’s hard to believe that I would not have noticed a piece of debris inching its way up from the bottom.” To us, this suggests the debris, both pieces, may have gotten in from the back hinge. Backing this up is Swiss reviewer Lorenz Keller, who tweeted at Bohn that his Fold also developed a bump, at a point that was the mirror opposite of Bohn’s defects. Keller’s bump eventually went away, which may be the result of the hinge being open enough to allow debris back out.

Photos make it clear that while the screen is supported on its left and right panels, there’s flex room between the panels, as there must be for the device to bend with such a tight radius. That means a thinly-encased OLED screen bends inward and potentially presses against objects that got inside. The inside of the device shows three hinges along the spine. If dirt can get into the spine of the Fold, it could also accumulate around those hinges, bringing them in contact with the fallible OLED layer, and that might explain the similarity between the bumps on Bohn and Keller’s review devices.

Samsung, in a press release Monday, stated that “initial findings from the inspection of reported issues” suggested “impact on the top and bottom exposed areas of the hinge,” and that there was an instance of “substances found inside the device (that) affected the display performance.” We’re not sure what to make of the impact claim, but we’re not surprised about “substances.”

Why make a device with a fragile OLED layer, so little tolerance between screen and spine, and so many ways for dirt and moisture to get in? Hubris? Testing with robots instead of real humans, with pockets and fingers and different ways of opening and closing things? These are questions that may go unanswered, even if we learn the cause of the defects.

Why Pre-Installed Screen Protectors Went So Wrong

Three of the review units that broke were due to the removal of a protective polymer layer that Samsung never intended for people to remove, as captured by Marques Brownlee.

Samsung states that the layer is not for human hands to remove, nor will it support additional screensavers. That tells you something about the display underneath. Pre-installed protective layers are not new; Samsung’s S10 series sports them. But because the flexible display is so fragile, people removing the protective layer—conditioned by years of removing the shipping plastic on their brand-new phones—are pressing their fingers and fingernails against the underlying surface, as well as applying uneven pressure across it. RIP OLED.

Robot Folding Versus Human Folding

What’s the difference between robots built by Samsung, Lewis from UnboxTherapy, and Dieter Bohn from The Verge? They all close the Fold with different gestures. Samsung’s robots, which the company states folded test devices 200,000 times, are pressing with perfectly even pressure across the phone’s outer plates, and opening with a similar even-force grace. In most situations, Dieter and Lewis press somewhere inside the display, on the display, to push the hinge out of its stay-open state and close the phone, then opening the phone up like a book, with their thumbs. Dieter tends to press near the bottom center of the Fold’s left panel, while Lewis, in opening and closing the Fold 1,000 times, hits a few different points in the middle and bottom. Yet another reviewer, Soldier Knows Best, closes the phone with a press in the upper-left of the inside display.

While no media review devices have yet failed due to folding issues, it’s worth noting that if any debris is inside the Fold’s hinge, or underneath the screen protector, pressing on the screen to close it could damage or aggravate the OLED enough to cause failures or problems. Neither reviewers nor yourself are likely to press very hard to close it, but uneven force, applied over thousands of instances, can lead to problems makers don’t always test for, Lionheart said. Samsung’s robots are running inside a cleanroom, while humans are using these devices in real-world conditions: lunch tables, outdoors, and in a hurry on the subway.

A Few More Potential Problems

From what we can tell, the Fold doesn’t seem to have a pre-scored line down the middle of the display to guide the screen when it folds. This is likely a benefit to the aesthetics of the device, so the screen resembles one big display instead of two distinct panels. But without a scored line, the pressure from folding is applied in many different places, instead of down one uniform line.

Lionheart, who majored in graphic communication at college and spent considerable time around printing presses and label applicators, wonders if the crease in the Fold “can wiggle a bit, if you push on one side or another.” That kind of uneven pressure could cause kinks or puckers on the display, which might be an alternate explanation for the damage seen in the Verge review phone.

Both Bohn and Lionheart said the Fold’s display would seem to need some kind of “play” or “float” to keep the screen from pressing against the edges of the case when opening or closing. “Like a carpet threshold, maybe,” Bohn said. Carpeting can stand to be pushed around a bit inside a container, but, as noted, OLED displays are not made to be bunched up or pressed upon by anything other than fingers.

We look forward to having more pictures and insights from the Fold as soon as we can take one apart. It’s a device with a lot of stories to tell.

Photos courtesy of The Verge.

Kevin is a staff writer at iFixit who likes fixing home networking, old bicycles, abandoned laptops, and sentences with too many words.

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