Just what is 2.5D screen glass?

by: Rob TriggsMay 27, 2015
2.5K

nexus 6 vs iphone 6 plus aa (10 of 24)

The 2.5D glass trend sounds like stereotypical marketing jargon… how can something exist between two and three dimensional space anyway? However, the term is actually based on a real design factor, it’s not just a name used to try and sell you semi-useless screen protectors.

2.5D refers to a slight curvature at the edge of the glass display, also known as a contoured edge. While not an official name for any piece of technology, it is widely used to reference this type of display design. You might not even really be able to notice it on some handsets, but on devices where the glass sits atop the rest of the body, rather than being secured behind a slightly raised bezel, you’ll certainly appreciate the more seamless edge.

A lot of phones have featured glass with some sort of curved edge over the years, but recently the design has become a much more prominent marketing term as handsets have tried to distinguish themselves based on aesthetic design. You can easily spot curved glass on modern handsets such as the Google Nexus 6, Xiaomi Mi Note, and now the Apple iPhone 6 too, just to name a few.

So, is it curved or not?

While not curved in the most obvious sense, the name refers to rounding off the edges of a flat “2D” display in the z-axis, adding a slight curve to what would usually be a straight edge. If you can’t quite picture this, a press slide from the launch of the Xiaomi Mi Note probably demonstrates the differences a little better than I can put into words.

Mi Note 2.5D glass

This effect can be made more or less extreme, depending on how much of a curved edge is required. Even a small curve can be used to make the edge of the glass feel smooth, while a larger curve may look more stylish.

Going further and actually bending the display leads to a more noticeable 3D effect. This is probably how we would describe handsets like the G Flex 2 or Samsung’s Galaxy Note Edge and S6 Edge, but these curved displays rely on bendable substrates and electronics too, while 2.5D glass does not. That’s not to say that these type of displays don’t feature curved glass edges as well, but it’s important to make the distinction about the term, now that handsets feature more noticeably curved displays.

How is it made?

Although a lot of fuss has been made about 2.5D glass, there’s nothing particularly special about the way it is designed and built. Because the actual electronic display components are not curved in anyway, unlike a flexible display, 2.5D glass is manufactured in much the same was as a straight glass panel, just with some additional shaping added when it comes to forming the glass to the right size.

It's a little more expensive, but can produce more premium looking results.

Fortunately, this means that 2.5D displays can still benefit from hardening and strengthening manufacturing techniques, such as those used by Corning’s popular Gorilla Glass. Individual smartphone sized glass pieces are cut from the larger mother sheet, with an additional processing layer thrown in to trim and smooth the edges of the glass. It’s a little more expensive, but can produce more premium looking results.

Xiaomi Mi Note-3

The shaped glass can then be put through the hardening process, by heating the sheet in a solution of molten salts at very high temperatures and then cooling it rapidly to force the glass to compress. Shaping and hardening is done in this order so that the structural integrity of the stronger glass is not put at risk by attempting to reshape it nearer the end of the processes.

For comparison, a fully curved display like the G Flex 2 or Galaxy S6 Edge requires that the display’s transistor backplane and circuit light elements, such as the OLEDs or LCD pixels, also conform to the curve. Flexible electronic circuits like this are even more complex and expensive to produce than the curved glass component.

What are the benefits?

The benefits of 2.5D glass are purely ergonomic and aesthetic. It is especially important on touchscreen devices to ensure that any surfaces that consumers are going to touch and swipe their fingers across are smooth. You wouldn’t want to snag your finger on a sharp glass corner!

You’ll still find 2.5D displays used in products with a non-glass edge, simply because it helps keep the edge of the glass away from the user’s fingers. Remember that intentional gap between the Note 4’s body and its metal frame? It would have been a big deal if sharp glass was exposed by the gap.

samsung galaxy note 4 first look aa (4 of 19)

In curved glass edge smartphones, 2.5D simply looks a little nicer than raising the bezel up above the display edge and helps to ensure that the glass fits nicely against the rest of the phone’s body.

2.5D has become a prominent marketing term as handsets have tried to distinguish themselves based on aesthetic design

As for toughness and scratch resistance, it’s the underlying manufacturing technique that determines these properties rather than anything inherent in the 2.5D name that specifies any such properties.

You’ll find that a number of Gorilla Glass handsets are also listed as 2.5D displays, but the two are separate terms. There’s also no reason to assume that these are any tougher or weaker than their regular flat glass counterparts. After all, it’s only the very edge of the display which is any different. 2.5D displays manufactured with a different process will result in different levels of toughness.

The only minor downside is that consumers who like to place an additional screen protector on their smartphone might find it difficult to find third party products that exactly fit the contours of the 2.5D glass. This is because the screen protector has to be manufactured to fit around the curves of the display, which is a trickier and more expensive process than producing a completely flat protector. You can find specific 2.5D screen protectors for these devices.

Overall, the term 2.5D display is not completely meaningless, but it’s not a major technical achievement that gives one phone an advantage over another either. A 2.5D display may lend itself to some nice looking designs, but it’s certainly not something to base your purchasing decisions on.

  • René

    That’s what I loved about the Nexus 4!

    • KenanSadhu

      Me too! (Though it’s before I need to keep it 24/7 in a case to prevent damage to the glass in the front and back)

  • Eric

    Before it became a thing for smartphone manufacturers, screen protector manufacturers used the 2.5D term to refer to their tempered glass with curved edges.

  • Unique

    htc did this with the one X

    • Peter Balga

      Sensation had it as well

    • Caleb Johns

      One X’s screen is weak as piss

      • Unique

        someone let out another Neanderthal

        • Caleb Johns

          I had a One X mate and used it until January 8 this year which was the day I purchased my Nexus 6. So don’t go calling me a Neanderthal when you don’t know the full story behind why I made that comment.

          • Unique

            First of all we’re not mates!
            second stop getting all up in your feelings
            Third if you are going to make a comment like you initially did …then explain. its no brain people like you that don’t think before you speak.
            oh just to add I don’t care about your story and I don’t think anyone else does either AND whatever you reply trust me we don’t care

          • Caleb Johns

            Piss off mate, you have to be so negative and please tell me who “We” are

          • KenanSadhu

            Not cool, “mate”. Not cool

          • Unique

            There’s no mates in the place lol

  • Roby

    Slightly raised bezels are more awesome.
    My mind is at ease knowing that my S5 isn’t sitting directly on the glass when I put it face down.
    Helps with drop protection too.

    • KenanSadhu

      It’s practically useful, but the S5 doesn’t look half as good as the note 4.

      • Roby

        Let’s not talk about personal preferences, shall we?Tried the Note in a store. It wasn’t as impressive or pretty as I thought it would be. The S6 Edge was a real looker tho, but seemed a bit too fragile.

        • digreene3

          It’s not. I have one and a slim case. dropped it a few times. still looks like new

  • lolz

    It is simply a marketing strategy,a gimmick. It may improve your overall experience but I think in real time use, you probably wouldnt notice at all.

    • Boolean Corporation

      The best tech is that one that works without being noticed.

    • Gimmick is the most overused word of the decade

  • rahul09

    androidauthority====== —->SEE INFO< <<<< >

    • Me

      rahul is a dumb whore who has no life.

  • dimz

    didn’t nokia use that technique for a time?

    • Roby

      I had that slightly curved glass on my N9 and it was a nice touch because you had to swipe in from the sides all the time in order to use the OS (MeeGo)

      • dimz

        That’s what I remember, ’cause a video review back then claimed that screen objects seemed to float much closer to the edge of the screen.

    • Mayush Jain

      Yes nokia used them from a long ……. Nokia deserves credit for lot of things

  • s2weden2000

    It’s 2.5D …

  • wrkerr

    In the case of a tempered glass screen protector, the rounded off edges serve to prevent the edge of the glass from chipping. A chip on the edge of glass can be very sharp, so I don’t know that I would necessarily agree that the change is “purely ergonomic and aesthetic.” Instead I think it reduces the likelihood that the glass will be damaged and need to be replaced.

  • corn

    when the next stupid useless tech will be? 5d, 5.6d? 7d?…

  • Thank you

  • Senthilnathan Sk

    Which Android phone is featured in the top-most picture?

    • Amzer Nazeer

      Reply after 2 months. Lol!
      Anyways, It’s Moto X Pure Edition.

  • Insidious Entropy

    They stole and translated this article: http://android.mobile-review.com/articles/35790/