

Your next smartphone might use sapphire glass instead of Gorilla Glass - JumpCrisscross
http://www.extremetech.com/computing/151146-your-next-smartphone-might-use-sapphire-glass-instead-of-gorilla-glass

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brc
I have a watch with a sapphire glass face. I must say, I have always been
impressed with its scratch resistance. Nothing I have done so far has
scratched the glass, and it's coming up on ten years. It's not from babying
the watch either, because the stainless steel bezel has developed quite a few
marks.

~~~
Shenglong
Interestingly, if you want to know whether something you own is sapphire
glass, you can usually conduct a simple experiment:

Drop some water onto the glass face, and jostle the item around a bit. If the
water stays put in a semi-uniform droplet, regardless of the motion and angle,
it's probably sapphire.

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biolime
What I'm curious to know is, is it shatter or crack-proof? I don't know anyone
who has "scratched" their phone screen but I see people all the time with
shattered screens (or backs of phones) because they dropped their phone. To me
it would be revolutionary if you could drop your phone without it cracking.
"Cases" would be a thing of the past (and rightfully so).

~~~
seanalltogether
So I imagine that most people when they shatter the glass on their phone its
because of compression of the glass. I found this
[http://abrisatechnologies.com/docs/AT%20Specialty%20Glass%20...](http://abrisatechnologies.com/docs/AT%20Specialty%20Glass%20Technical%20Capabilities%20Brochure.pdf)
that says gorilla glass has a compressive strength of 800 MPa, and this
<http://www.roditi.com/SingleCrystal/Sapphire/Properties.html> says that
sapphire has a compressive strength of 2.0 GPa.

Additionally the flexural strength of sapphire appears to be ~20x higher then
any of the "bending strengths" listed in that pdf

~~~
acchow
I'm afraid of shattering from dropping the phone. Does that translate into a
compression? Or something else? (vibration?) Honest question.

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ajtaylor
I can't believe no one has mentioned this already, but Mr Scott can now have
his transparent aluminium.

~~~
kiba
Sapphire is aluminum oxide. The transparent aluminum you're talking about was
invented in 2009.

~~~
ajtaylor
I know it's not exactly the same, but I couldn't resist the temptation.

~~~
acchow
Not exactly the same? It's not at all the same. It's like calling oxygen (O2)
"not exactly the same" as water (H2O), but you couldn't resist because they're
both mostly transparent.

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saosebastiao
Sapphire glass is already used on Vertu's phones...although the author
probably didn't notice due to the fact that nobody is that dumb.

~~~
kragen
Vertu still exists? What do you mean by "that dumb"?

~~~
aaronbrethorst
Nokia sold Vertu to a private equity group last year[1]. "That dumb" means who
in their right mind would pay $10k for a phone[2]? Unless they were Kanye
West[3]. And even he's an iPhone user[4].

[1] <http://www.eqt.se/en/Portfolio/Companies/Vertu/>

[2] [http://www.forbes.com/sites/jonmatonis/2013/02/21/silent-
cir...](http://www.forbes.com/sites/jonmatonis/2013/02/21/silent-circle-and-
vertu-partner-on-10000-phone/)

[3] <http://rapgenius.com/38105>

[4] Or at least was in 2010.
[http://www.vulture.com/2010/11/in_the_studio_with_kanye_west...](http://www.vulture.com/2010/11/in_the_studio_with_kanye_west.html)

~~~
kragen
Vertu's theory was that people who'd pay $10k for a watch (or, say, a painted
cloth square) would be willing to pay $10k for a phone. I'm interested to hear
that they've been successful enough at that to interest a private equity
group.

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avelis
I hope I am not asking a dumb question but would there be any complications
with capacitive touch using sapphire glass over currently implemented gorilla
glass? The video didn't demonstrate actual phone usage with the sapphire glass
overplayed on top of the phone.

~~~
joezydeco
Wondering the same thing as well, and I've worked on capacitive screen design.
The dielectric constant of sapphire seems to be better than glass[1] for this
type of application, so it should be okay.

[1] [http://www.st.com/st-web-
ui/static/active/cn/resource/techni...](http://www.st.com/st-web-
ui/static/active/cn/resource/technical/document/application_note/CD00222015.pdf)

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rtwtlkj
>>There’s one caveat: according to a market analyst, a sheet of Gorilla Glass
costs around $3, while the same piece of sapphire glass would cost $30

I'm already paying a lot of money for the smartphone what difference does it
make another $30-$50 dollars. Especially considering that is far more
expensive to replace the screen of the phone and in a lot of cases you'll have
to replace the entire phone which will cost you a couple hundred dollars.

~~~
randall
Admittedly this is the most unscientific of sources, but this Yahoo Answers -
_ducks_ \- post claims Sapphires have a hardness of 9 out of 10, where 10 is
diamond. That leads me to believe it'd be harder to crack than glass.

~~~
svachalek
I believe hardness has more to do with scratching than cracking; e.g. plastic
is harder to crack than glass, but softer.

~~~
rayiner
Indeed, cracking is generally inversely related with hardness. Harder things
are easier to crack than softer things.

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mnl
Sandpaper can scratch sapphire, as it is made of particles of carborundum.
Same with some stone garden furniture. Sapphire is quite brittle: it has lower
shock resistance than glass, that's why quite expensive sports watches use
some kind of glass, or plexiglass (famously, the Omega Speedmaster selected
for the Apollo had a hesalite crystal).

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ars
I'd be happy to pay an extra $27 for this. No more screen protectors needed.
Alumina is harder than most metals.

~~~
bigiain
The problem there is it's an additional $27 on the manufacturing BOM cost (or
possibly $54 for an iPhone with front and back glass). By the time all the
markups on the way to the retail store get applied to that you'd be looking at
more like ~$90 extra, or $180 for both sides on an iPhone.

(Markup estimate based on BOM cost and Retail pricing here:
[http://www.isuppli.com/Teardowns/News/pages/iPhone5-Carries-...](http://www.isuppli.com/Teardowns/News/pages/iPhone5-Carries-$199-BOM-
Virtual-Teardown-Reveals.aspx) )

~~~
potatolicious
The unibody machining costs back when the MacBook Air first came out was
pretty ludicrous too - $1800 for a MBA if I remember correctly.

Now it's $900, and the same process has been streamlined to the point where
even mid-range phones have this sort of construction.

We just need someone to lead the charge.

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dutchbrit
The sapphire is susceptible to chipping or shattering if whacked hard enough
or dropped (a bit like toughened glass...hardness usually means more brittle).
Diamonds are the main cause of scratches, but softer materials can also still
cause scratches....

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qthrul
Anyone wanting to learn about what could come after what comes after should
read up on transparent spinel specifically.

<http://en.wikipedia.org/wiki/Transparent_ceramics>

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rogerbinns
My problem with current screens is that they functionality exceptionally well
as mirrors first, and then also display some stuff through the reflections as
secondary functionality. I really wish they would fix that first.

~~~
nmdtyvb
But shiny screens bring more attention at retail store.

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manicdee
Couldn't read the article. Half way through a paragraph on their faux-swipable
layout you are shown a full screen ad for some movie comparing the White House
to Olympus.

~~~
meej
That's Onswipe, and it's my least favorite thing about browsing the web from a
mobile device lately. It's slow, the ads have become really irritating
recently, and there's no way to preemptively tell a site you don't want to use
it.

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dghughes
A bit ironic, if I read it right Gorilla Glass has a (Mohs hardness) of about
7 or 8.

Aluminum is about a 6 but oxidized luminum is corundum/sapphire is about a 9.

The one thing you may have had in you pocket, oxidized aluminum object, will
now be the entire screen.

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EvaK_de
Actually sapphire is NOT "the hardest natural substance after diamond".
Moissanite seems to be. It has a hardness of 9.5/10 (sapphire: 9/10) and
occurs naturally, but can also be produced technically.

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uribs
Are industrial diamond screens also a possibility?

Since diamond is harder than sapphire, they would seem a better choice, but
maybe there are other drawbacks.

~~~
jonah
Are they making diamonds that large?

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callil
Artificially, sure why not, its just compressed carbon.

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wyager
It's (quite) a bit more complex (and expensive) than that. You can't just push
a lump of carbon really hard into a sheet. You have to worry about all sorts
of things to get a high-quality crystal, and making crystals that are both
optically high-quality and large is very expensive.

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ricardobeat
This was solved 50 years ago. Interesting read:
[http://www.pbs.org/wgbh/pages/frontline/programs/transcripts...](http://www.pbs.org/wgbh/pages/frontline/programs/transcripts/1209.html)

~~~
wyager
What was solved 50 years ago? Just because we can make synthetic diamonds does
not mean we can make synthetic diamonds of any arbitrary size or quality. In
fact, it becomes exponentially more expensive in proportion to the volume of
the produced diamond. Most artificial diamond companies limit mass to 2-300mg
per diamond because it gets much more expensive after that. Of course, we are
speaking of optical-quality monocrystaline diamonds here. Polycrystaline
diamonds are less expensive, but unsuitable for optical equipment (e.g. cell
phone screens).

That's not to say the problem is hopeless; in fact, there has been some very
interesting research done in recent years on low-pressure microwave-based
diamond synthesis that could allow for very large, kilocarat-scale diamonds.
But for now, it is not feasible (as far as I know) to produce diamonds in the
shape and size needed for cell phone screens, and certainly not at low cost.

