In the past 24 hours, the world's top tech companies have placed big bets on curved screens. Samsung on Monday launched a massive, curved television. Its fellow South Korean rival, LG, announced both a curved TV and a curved smartphone, the G Flex. Both companies are even showing off HDTVs whose screen you can bend on demand by pressing a remote.

Whether there's actually a market for these devices, or if they're just outlandish proofs of concept, is anyone's guess. For how much they cost, the bendy screens don't seem very worth it. But gimmickry aside, the technology behind these devices is the real achievement, because they point to a future where flexible materials have become a common fixture everywhere — and not just in the living room.

"It's a big leap forward," said John Richard, the global business manager of DuPont's displays division.

How does this stuff actually work? To get a basic grasp, it helps to draw a distinction between curved displays and flexible ones. Curved displays, said Richard, generally involve a standard flat panel display that's been bent after the fact. Flexible ones, meanwhile, offer a lot more promise because they're capable of bending back and forth more than once.

The key to both is glass. For centuries, glass has been a rigid product that breaks at the slightest pressure. Yet recent advances mean engineers can now embed bendy glass right into the innards of a device.

There are two types of display technology: LCD screens and OLED screens. This is the stuff that forms the images you see on your smartphone or tablet, or watch on your television. It generally has to be applied on a layer of glass and buried behind other additional layers before being covered up by the main piece of glass you touch with your fingers.

Until recently, LCDs and OLEDs could only be applied to flat surfaces. Then, in 2012, Corning — the company behind Gorilla Glass and your parents' dishware — unveiled a flexible kind of glass called Willow. Willow is about as thin as a piece of paper and comes off the production line in gigantic, 300-meter-long rolls. It's been chemically coated to conduct electricity and enhance transparency. According to Vinita Jakhanwal, an industry analyst at IHS, these and similar types of glass make it possible to build rounded surfaces that can accept LCD or OLED layers.

"What they're trying to do is make glass that is very thin,"  Jakhanwal said. "The thinner you get the glass, the more you can get a curvature in the glass itself."

It's not clear whether Samsung and LG's TVs at CES just use a flat display technology with a curved piece of glass in front of it, or if the inner layers themselves were designed using curved materials. Certainly the prototypes that can bend on demand could have some kind of flexible glass in them.

There's still a limit to how far this stuff can bend; you can't crumple it up like paper. Nonetheless, once you've figured out how to manufacture the stuff, it's an easy jump to the next level.

"All you have to do is apply pressure using a motor," said Brian Blau, an analyst at Gartner.