Hi everyone. The other day we had a conversation discussing the Gorilla Glass (GG) and factors that affect its strength. As you have seen in @Mike post, he bought a OnePlus 3 (OP3) phone and its screen shattered after seemingly innocent fall. OnePlus claims the OP3 comes with GG4, which should be pretty resilient to impacts. I too have a OP3 as my daily driver and so far, my OP3 has survived two pretty scary falls. The only difference that I and Mike have in using our phones is that I am using the official OnePlus wooden case. If you are not familiar with those cases, they are real wood veneers layered and shaped to be paper thin. Their purpose is decorative at best, and offers little to no protection. Or does it…?
There is regular glass, crystal glass, tempered glass, laminated glass and chemically hardened glass, like GG. The general rule of thumb is that the regular glass is the easiest to work with as you can shape, sand, drill and bend it, however it is the least resistant and will break on impact.
The hardened glass works by putting the outer surfaces into compression and the inner surfaces into tension. The compressed particles are harder to break apart and thus it is harder to break the glass. Chemically treated glass like GG adds an additional step of surface ions replacement. By swapping in larger ions an even bigger compression level can be achieved, thus making the glass stronger.
So the theory behind the fortified glass is pretty straightforward, but as I learned, things get murky when you start getting into the details of the fortified glass. Fortified glass, as it turns out, is a tricky material that can take a multitude of characteristics based on its composition, how it is machined and treated, and most importantly how it is shaped and how the edges are protected. To my understanding the last part has a lot to do with the balance of compression and tension forces within the glass. So if you chip enough material from the glass the imbalance will shatter the whole piece. And what is the best place to chip off the material, of course the edges or the corners. So the more cutouts and the longer the edge is the weaker the glass becomes. Then there is the contoured edge glass, where the edges are rounded off and left exposed (ex. iPhone 6 and newer, OP3 and others), making for additional opportunity for damaging it.
Judging from the above it seems that simply knowing that your device has say GG4 vs other device’s GG3 does not guarantee that your device’s glass will be more resilient to breakage, and the only way to really judge how resilient the glass is to test the actual devices under controlled identical conditions. What I can conclude from this is that generally the simpler the shape and the least cutouts, the more resilient it will be and having higher rated strength glass (i.e. GG4 vs GG3) will make it even stronger, but only when comparing identical shape, thickness and edge treatment.
So does the wooden case actually protect the OP3 screen? It seems it does, to a degree that it provides this tiny lip on the edges of the OP3 where it shields the contoured edge against direct impacts.
Talking about contoured edge glass brings my attention to another question – would having a curved edge glass like on Samsung S EDGE series make it any more resilient than having the contoured edge glass like on IPhones and OnePlus? Share your thoughts and experiences below.
