Glass is glass, right? It's clear, makes noise when you knock on it. Does bad things if you knock on it too hard. Turns out there's a lot more to glass than you might think, especially when it comes to televisions.

You've probably heard of Corning before. Maybe you or your grandma had or have Pyrex glassware in the kitchen. Maybe you have any number of recent smartphones with a Gorilla Glass display that doesn't get scratched when you put it in your pocket with your keys like an animal.

What you might not have known is Corning is probably in your TV, too. And since glass isn't just glass, they've come up with some new technology that might make your next TV even better. Let's take a look.

Glass bits

Just like hot dogs, TVs are sandwiches. They're layers and layers of different materials sandwiched together as closely as possible with the end result being a big bright-and-shiny for your eyeballs.

As you can probably imagine, TV manufacturers want to simplify how many layers are needed. This makes the TV thinner, which is good for you, and cheaper, which is good for them and for you. They do this by combining layers, minimizing parts, misplacing others, and so on.

Corning

The problem is, there's only so much simplicity they can add. You get to a point where the actual structure of the TV is compromised. Sure, bendy, foldable TVs could be the thing of the future, but bend a TV now and you've got a sad paperweight.to

Which is why, perhaps counter-intuitively, TV makers often switch from plastic to glass. Plastic was great for a while, and still is for many parts, but glass offers multiple benefits. The first is that it's stronger, structurally, than thin plastic.

I know what you're thinking -- how could a thin piece of glass be stronger than plastic? Well, think of it this way: the front part of your smartphone is glass, and it's way tougher than plastic.

Sure, beyond a certain point glass will crack or shatter, but up to that point, it's far more rigid. Or to put it another way, a thin piece of plastic that's 50 inches diagonally is going to have difficulty standing perfectly upright without support. But a piece of glass that same size, and even thinner, is rigid enough to not fold over or warp.

Corning

The second benefit of glass is in light transmission. All "clear" objects still block some light. How much, and what wavelengths, can be a big factor in TV design. One material could be super-cheap, but blocks more blue light, meaning the TV isn't as bright or is less efficient. Another material could cost more, but allow for more light to pass through, meaning the TV is more efficient. Along those lines, the TV could be same efficiency as a different design, but cheaper to build in another way (say, a cheaper power supply, for example).

This is actually a good takeaway for this entire thing: there are tradeoffs with any design, and where a designer spends money and what the tradeoffs are of each element, all play a big factor in the overall design of the display. Spending more on one part so you can spend less on another could be a big win overall.

Iris

Which brings us to Corning's Iris glass. It's designed for use in a crucial part of the TV: the light guide.

With edge-lit LCDs, the LEDs to create the light are in the bezels, facing inward toward the center of the screen. The light guide redirects this light by 90 degrees (roughly) so it shines toward your eyeballs. Historically, the light guide has been made of plastic. It's a big change to be able to make it out of glass.

Corning

A glass light guide lets TV manufactures build brighter and thinner TVs. That's the theory, anyway. Iris glass, Corning claims, is exceptionally transparent: More light goes through, so the TV can be brighter.

Iris glass is also thinner and stronger than plastic. That makes the TV itself slightly thinner, of course, but because it doesn't need the structural bracing of the plastic layer it's replacing, those structural parts can also be removed from the overall design. So even if Iris glass costs more than the plastic it replaces, fewer parts overall are needed.

Part of the size saving also have to do with reducing or eliminating the "air gap" between layers in an LCD (the gray parts inside the TVs in the diagram above). Because plastic expands when it gets hot, some "wiggle room" must be built into the overall design. These gaps of air aren't required with glass, since it's not so affected by temperature. This is sort of like how you can cook with certain types of glass, like Pyrex, and it doesn't just shatter like you might expect.

Glass future?

It's perhaps odd that one of humanity's oldest technologies is getting more use in the future of TV tech, not less. Other glass tech, like Corning's scratch-resistant Gorilla Glass, and similar tech like Asahi Glass's Dragontrail and Schott's Xensation, show that glass is an integral part of current and future technology. Will diamond glass be the next thing? Maybe.

For now, advancements like Iris glass mean the potential of thinner, brighter TVs, at potentially lower prices. You'll probably never see "Corning Iris Glass" written on any marketing. After all, you aren't the consumer for this. TV manufacturers are. But you will see the benefit. As LCD TVs get even more impossibly thin, it's due in part to advancements like these, allowing the overall design of the TV to change in ways that are hard to see directly, but the results of which are a noticeable improvement.

Got a question for Geoff? First, check out all the other articles he's written on topics like why all HDMI cables are the same, TV resolutions explained, LED LCD vs. OLED and more. Still have a question? Tweet at him @TechWriterGeoff, then check out his travel photography on Instagram. He also thinks you should check out his best-selling sci-fi novel and its sequel.