Coring Hopes TV Makers Go Ape for Cover Glass

Corning is helping Sony celebrate the launch of its new 2011 Bravia LCD TV models, which are among the first flat-panel sets to use Corning’s highly durable Gorilla Glass formulation as screen covers.

Corning defines Gorilla Glass, which has seen applications in cell phones, tablets and PC monitors, as an environmentally friendly alkali-aluminosilicate thin-sheet glass that is lightweight and durable under a range of challenging conditions that could cause other glass approaches to fail.

Although the glass has been around for several years in handheld devices including some smartphones, Sony several weeks ago became the first manufacturer to ship TVs using Gorilla Glass cover applications, said John Bayne, Corning TV cover glass program director.

The company had an exclusive on the glass technology until it announced its first sets using the material several weeks ago. Corning is now pitching its use to other set makers.

Bayne said Sony selected the glass for three stepup Bravia LCD TV series that have an edge-to-edge glass look that compliments the monolithic styling design.

Gorilla Glass is offered in three 2011 Sony Bravia LCD series including: the XBR-HX929-series (46, 55 and 65 inches), the HX820 series (46 and 55 inches), and the NX720 series (46, 55 and 60 inches).

To achieve panel strength in the past, glass panel makers have traditionally relied on thermal tempering techniques which give greater strength but require 3mm-5mm added thicknesses, which can add eight to 10 pounds to the weight of a 46-inch set, for example.

To make Gorilla Glass, Corning chemically treats the glass in a bath of potassium nitrate. The potassium nitrate molecules in the bath try to get into the glass as the smaller sodium molecules in the glass try to get out of the glass in a diffusion process. This puts the entire surface under compression.

For glass to fail it requires a small flaw and tension on the glass.

Bayne explained that the beauty of putting the surface of Gorilla Glass under high compressive stress is that it makes it hard to introduce a flaw, and even if a flaw develops over time, breaking the glass requires overcoming that compressive stress before putting the surface it into tension.

Corning developed Gorilla Glass four years ago at a request from the cellphone industry. It is currently used on 350 products for 30 brands, representing over 200 million units in the market worldwide to date.

Most of those were handheld items, until Sony approached Corning in late 2009 about working together for larger TV displays. The formulation developed for Sony enabled a .7mm thickness, which significantly reduced unit weight from 3mm cover glass with even greater damage resistance.

Gorilla Glass is used only used for cover glass over an LCD panel and not in the panel itself, so it is put on in the final assembly process at Sony factories, Bayne said.

Best of all, Bayne said, Gorilla Glass is optimal for use on 3D sets, which he said can’t be built using thermally tempered glass.

“Our glass has very, very low stress by refringence because of the diffusion platform we use,” Bayne, said. He added that thermally tempered glass is full of nonuniform stresses, which are bad for 3D.

“Based on polarization of light any stress by refringence is bad for 3D because it means the polarization for one axis is affected differently than the other, and that can produce ghosting, cross-talk and other artifacts,” he said.

Corning is manufacturing Gorilla Glass in several facilities in the U.S. and Asia, including a facility in Shizouka, Japan, which was the first glass facility Corning built in Asia, back in the mid 90s.

It is currently supplying Sony with sheets used to cover up to 65-inch TVs right now, and he said, Corning could probably produce panels of Gorilla Glass for up to 70-inch sets, with the only limitation coming from the size of ion-exchange tanks used to manufacture the panels.

“We are actually making Gen 10 (LCD not Gorilla) size sheets, which would be 3 meters on a side. The manufacturing platform is capable of going larger, but right now we don’t have any reason to,” said Bayne.

Corning can ship glass to Asian manufacturers out of the Shizouka plant as well as several other facilities on the continent.

Bayne said Corning is now looking at plasma applications for Gorilla Glass.

“My understanding of plasma is that they have been using [cover glass] from the earliest days, but for a different reason – to put on coatings to protect from electromagnetic interference coming from the plasma set. We haven’t seen as much of a pull from plasma makers yet, but we are having discussions to see if they would be interested in applying Gorilla Glass,” Bayne said.

Corning is beefing up its promotion and advertising for Gorilla Glass, though Bayne stops short of comparing the effort to Intel’s famous Intel Inside campaigns. The company is running a Urban Gorilla campaign now in print and Web advertising showing a gorilla playing with cellphones, laptops and other devices that use Gorilla Glass covers.

“The goal of our [Urban Gorilla] campaign is to make people aware that the cover material matters and that Gorilla Glass is a great choice,” Bayne said, adding that so far it has been very successful.

Corning is using co-branding with Sony on the new Bravia TVs, advertising on the box the use of Gorilla Glass in the set, while Sony added a microsite to its Web site to explain the benefits of using Gorilla Glass.

As for reducing the tendency for some LCD TVs to be susceptible to surface scratching, Bayne said it all depends on whether the set maker using an AR film.

“Right now, almost every LCD set maker uses some form of AG or AR coating process, just because viewing with ambient light in the home is going to produce some reflections off the screen,” Bayne said