An inside look at Corning’s labs suggests what’s next for the inventor of Gorilla Glass.
Someday
your smartphone might be able to help you in a new way when you’re
traveling: by telling you whether the water is safe to drink.
Although a water app isn’t close yet, researchers at Corning and
elsewhere recently discovered that they could use Gorilla Glass, the
toughened glass made by Corning that’s commonly used on smartphone
screens, to make extremely sensitive chemical and biological sensors. It
could detect, say, traces of sarin gas in the air or specific pathogens
in water.
The sensors are just one project I learned about during a visit to
Corning’s R&D labs in upstate New York. In the last few decades,
Corning’s advances in glass-making have led to technologies such as
fiber optics and flat-panel displays. Now, thanks to Gorilla Glass, it’s
associated with the latest smartphones. But despite the remarkable
success of that product, it is keen to catch the next high-tech boom.
Corning spends about 8 percent of its sales on R&D—which will
amount to about $800 million this year. It’s a hedge against the very
real possibility that one of its businesses could go dark—as has
happened in the past. Between 2000 and 2002, Corning lost more than half
of its revenue when its fiber-optics business collapsed with much of
the rest of the telecom market. Its stock plummeted from $113 to just
over $1. This year, it got another scare when one of its largest
customers, Apple, came close to replacing Gorilla Glass in iPhones with
sapphire (see “Why Apple Failed to Make Sapphire Phones”).
Displays, in one way or another, account for about half of Corning’s
revenue, with roughly a third of that coming from Gorilla Glass. To
expand this market and withstand challenges from other materials,
Corning is trying to add capabilities to Gorilla Glass, such as the
sensor application. And it’s looking for new markets for Gorilla Glass
beyond displays.
The ability to turn your phone into a biological and chemical sensor
is one of the earliest-stage projects in the lab. Researchers at Corning
and Polytechnique Montreal discovered that they could make very high
quality waveguides, which confine and direct light, in Gorilla Glass.
The researchers were able to make these waveguides very near to the
surface, which is essential for sensors. Doing so in ordinary glass
would break it. Making the waveguide involves focusing a beam of intense
laser light near the surface of the glass, then tracing it along the
glass, which locally changes its optical properties.
To make a sensor, the researchers make a waveguide that splits into
two identical pathways for light. Then the paths converge, and the light
from both paths meet up. One path serves as the sensing path, and the
other as a reference. Even a tiny change to the light in the sensing
path—such as its intensity—can be detected by observing how the light
from the two paths interacts when they meet, producing distinct
patterns.
The researchers demonstrated a simple sensor that detects changes in
temperature. Heating up the sensing path changes its shape, which
changes the properties of the light passing through it. Because the
waveguide is so close to the surface, part of the light actually extends
out of the glass, and anything placed on the surface of the glass will
interact with part of the light. This means that to make a chemical or
biological sensor, you could prepare the surface of the glass so that a
specific target will bind to it. For example, you might treat it with
antibodies that latch onto E. coli. or other contaminants; detecting
their presence would be as simple as putting a drop of water on the
phone.
The waveguides are microscopically thin, and therefore invisible, so
they wouldn’t obscure a display. And because they’re quite small,
sensors for several different biological or chemical targets could be
incorporated into a smartphone.
Corning researchers have also discovered that Gorilla Glass has
useful acoustic properties. The way it vibrates is different than
conventional glass—it damps sound waves. The simplest application is
noise insulation—it blocks sound better than ordinary glass.
But the same acoustic properties could also turn displays into
speakers. I saw such a prototype in one of Corning’s labs. A wire in the
display attaches to a small actuator that vibrates the glass to produce
sound waves. Because of the way the waves propagate through the glass,
they can be more precisely controlled than with ordinary glass, allowing
for higher quality sound reproduction.
In another lab, researchers showed off a seemingly ordinary window.
Then, with a flip of a switch on a circuit board, it turned into a
display—one showing an old Coke commercial—and I could only barely make
out what was behind the image. When the ad was over, I could see through
the display again. Corning was particularly secretive about how it
managed to make this technology work.
The most uncanny thing I saw was a Slinky-like glass toy. It’s made of
thin Gorilla Glass cut in a spiral shape with a new laser manufacturing
tool. As with a Slinky, if you hold one part and let go of the rest, it
extends toward the floor. Ordinary glass would just shatter, but because
it’s tougher, this glass springs back like plastic. The key to having
glass this flexible is making it thin.
Corning recently developed Willow Glass, which is about 100
micrometers thick, one-fourth the thickness of the Gorilla Glass
normally used for displays. It can be shipped to customers in rolls,
making it easier and cheaper to use in manufacturing. Potential
customers are still evaluating how to use it; one likely application is
as a component inside displays. But already, an even more flexible kind
of glass is in development, says Corning’s chief technology officer,
David Morse. It can fold around the edge of something as thin as a
reporter’s notebook, and do so millions of times without breaking. It
could be important in future foldable electronic devices.
Founded in 1851, Corning survived in the past because of its ability
to keep reinventing the possibilities of glass. At about the same time
that the market for fiber optics collapsed, its business selling glass
for cathode-ray-tube TVs also took a steep dive. It was saved by a
process it had invented for making the high quality glass needed for the
transistors that control pixels in LCD displays—the very display
technology that was destroying its cathode-ray business. A few years
later, the company got a call from Steve Jobs, who needed tough glass
for the first iPhone. Corning just happened to have a technology sitting
on the shelf—the toughened glass that came to be called Gorilla Glass.
Corning hopes to be ready for the next call.
Title :
Chemical-Sensing Displays and Other Surprising Uses of Glass
Description : An inside look at Corning’s labs suggests what’s next for the inventor of Gorilla Glass. Someday your smartphone might be able to help...
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