Glass enabling future touch technology

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In 2007, Corning launched Gorilla Glass, a tough glass product that is ideal for touch screens and many other applications. Because of Corning's proprietary fusion manufacturing process with automated robot arms precisely drawing glass in a clean room environment along with a chemical tempering procedure, Gorilla Glass has a very clean and even surface of excellent quality, and there are different product sizes to flexibly meet the specifications of LCD TVs and monitors. Since its launch, as many as 33 world-renowned brands and 750 types of devices have adopted Gorilla Glass, and Gorilla Glass can also be found in more than 750 million products in the market.

Strengthened hardness and damage resistance of Gorilla Glass 2

According to James Hollis, Worldwide Sales & Applications Engineering, Corning Glass Technologies, the features of Gorilla Glass have changed the traditional perception of glass, and Gorilla Glass has been widely applied to the coolest smartphones, tablets, PCs, TV, and other consumer devices to enable scratch resistance in daily normal use.

As the interaction between consumers and various smart devices is becoming increasingly frequent anytime and anywhere, the thinness, lightweight, ligh transmission, durability, as well damage/scratch resistance of new generation glass products must be improved in order to meet the requirements of various applications, such as optic fiber lighting, automobile glass, architectural display glass, electrochromic glass, all-weather surface glass, antimicrobial glass, optimized components for 3D glass, transmissive display glass, for living rooms, bedrooms, classrooms, vehicles, hospitals, and open space.

In order to let glass materials more easily blend into the future applications, Corning has recently launched Gorilla Glass 2, which is as outstanding as its predecessor in optic performance, scratch resistance, and cost efficiency, while completely compatible with the existing parts manufacturing processes. But it features significant form factor and damage resistance improvements.

According to Hollis, with all other things being the same, the load-to-failure of Gorilla Glass 2 after abrasion is at least 25% higher than Gorilla Glass. In other words, with the same damage resistance, Gorilla Glass 2 is 10-20% thinner than its predecessor. For example, at a failure load of 170kgf, Gorilla Glass 2 can be 2mm thinner than Gorilla Glass, while 10-15% of the strengthening time during production is saved.

Lighter and slimmer smart devices enabled by OGS

In order to meet the needs in manufacturing large full-touch screens, Corning has a one-glass solution (OGS) combining the touch sensor and cover glass into one, allowing the ITO to be patterned directly on the underside of large-size cover glass. Such single-sheet glass is both a strong and safe cover glass and a touch sensor.

For projective capacitive touch, according to Hollis, the conventional discrete touch module needs an extra ayer of glass with both sides pattenred with ITO. But now the OGS integrates the touch sensor and cover class into one to do without the thickness of an extra sheet of glass. This not only reduces weight but also simplifies the materials and manufacturing process to decrease panel thickness. It enhances light transmission, and the production process is streamlined.

Because of different sequences of sensor processing as well as glass cutting and strengthening, there are two different touch panel making processes: full sheet and discrete sheet processes. According to Hollis, the discrete sheet OGS will directly hand over Gorilla Glass 2 to glass finishers for cutting, as well as the machine and ion exchange processes. Then it is handled by touch panel makers for deposition, patterning and registration. The last step of assembly is completed by ODM companies.

The full sheet OGS first will see Corning make the IOX-FS glass substrate from Gorilla Glass 2, and then deposition, patterning and registration are done at touch panel makers. After the cutting and machine processing, assembly is lastly completed by ODM companies. Whether the cutting takes place before or after IXO, the Corning glass still supports OGS.

OGS issues improved by IOX-FS

Before the Corning IOX-FS substrate was available, OSG could save costs and enhance capacity utilization, but device durability was weakened considerably by fragile edges of glass panels because the substrate was cut after strengthening. The cutting incurred stress and made edges fragile.

The OGS-based IOX-FS glass performs much better than soda lime glass in terms of surface damage resistance, critical stress, edge strength, and light transmission. For example, the surface damage resistance and critical stress of IOX-FS are respectively 5-7 times and more than seven times soda lime glass, enabling a smaller form factor, design flexibility, enhanced durability, better scratch resistance, high-definition, higher display brightness, lightweight, and richer colors on displays. Material and production issues are improved, too.

The toughness of Gorilla Glass allows thinner glass to be put on various devices and more importantly the devices' lighter weight makes it easier for transportation and therefore reduces transportation costs. Soda lime glass needs to be 5mm thick to achieve the same toughness of Gorilla Glass of only 0.7mm, said Hollis. Soda lime glass for a 70-inch screen can be as heavy as 17.6 kg but 2.5kg of Gorilla Glass will be enough - a great difference of 15kg, Hollis added.

According to Hollis, the current international freight rate charges US$2.2/kg, and US$33 can be saved if an item is 15kg lighter. Thinner displays amount to more space for other cargos for each shipment, and freight efficiency is therefore enhanced, said Hollis.

Better user experience that is also more interactive

Moreover, Gorilla Glass effectively reduces screen parallax and improves touch control accuracy to provide better visual quality. The parallax of 5.0mm soda lime glass is 2mm when viewed at an angle of 25 degrees. The parallax is 4mm at angle of 45 degrees and it increases to higher than 10mm at 75 degrees. But the parallax of 0.7mm Gorilla Glass is lower than 1mm and increases only slightly when viewed at an angle of 75 degrees.

The touch sensitivity of Gorilla Glass is also 40% higher than thinner soda lime glass based on parallel-plate capacitor approximations, and such a feature is critical to high-definition touch panels. Direct lamination that eliminates air from the gap improves contrast ratios and rigidity to provide superior viewing quality.

Established in 1851, Corning creates and makes keystone components that enable high-technology systems for consumer electronics, mobile emissions control, telecommunications, and life sciences. The company now has 29,000 employees around the world, including more than 2,000 employees in Taiwan. Its 2011 revenue came to US$7.9 billion. Corning is the 328th of the 2012 Fortune 500 companies and the world leader in ceramics and specialty glass.

According to Hollis, Corning succeeds through sustained investment in R&D, more than 160 years of materials science and process engineering knowledge, and a distinctive, collaborative culture. Corning excels in combining its abundant professional knowledge with its service to local customers in order to enjoy success together with customers. It is Hollis' view that people live in a world made from glass will soon become a reality as more and more companies are embracing Corning products.

James Hollis, Worldwide Sales

James Hollis, Worldwide Sales & Applications Engineering - Gorilla, Corning Glass Technologies, Corning

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