Property of Cover Glass in Capacitive Touch Screen Corning Incorporated Founded: • Corning is the world leader in specialty glass 1851 and ceramics. • We create and make keystone components Headquarters: that enable high-technology systems for Corning, New York consumer electronics, mobile emissions control, telecommunications and Employees: life sciences. Approximately 25,000 worldwide • We succeed through sustained investment 2007 Sales: in R&D, over 150 years of materials science and process engineering knowledge, and a $5.86 Billion distinctive collaborative culture. Fortune 500 Rank: 417 Technical Materials © Corning Incorporated 2008 2 Corning market segments and additional operations Display Telecom Environmental Life Specialty Other Technologies Technologies Sciences Materials Products & Services •LCD Glass •Optical Fiber & •Emissions •Cell Culture & •Advanced Optics & •Display Futures Substrates Cable Control Products Bioprocess Materials – Automotive •Display Optics & •New Business •LTPS-LCD Glass •Hardware & – Diesel •General Development – Stationary Components Substrates Equipment Laboratory •Semiconductor í Coaxial Products Optics & •Drug Discovery Connectivity Technology Products Components •Aerospace •Steuben Glass •Astronomy •Optical Metrology •Equity Companies •Ophthalmic – Dow Corning Corp. – Eurokera, S.N.C •Telecom – Samsung Corning Components Precision Glass •Specialty Glass Company, LTD (SCP) GorillaTM Glass Technical Materials © Corning Incorporated 2008 3 A culture of innovation High-throughput Glass envelope for Ceramic substrates label-free screening Thomas Edison’s Dow Corning for automotive platform for light bulb silicones Glass ceramics catalytic converters drug discovery 1879 1915 1934 1947 1952 1960 1970 1972 1984 2006 Heat-resistant Processes for mass Fusion draw First low-loss AMLCD glass for Pyrex® glass producing the process optical fiber computers and television bulb large screen TVs Technical Materials © Corning Incorporated 2008 4 Capacitive Touch Screen Structure Technical Materials © Corning Incorporated 2008 5 Current Tech Surface Capacitive is currently the 2nd largest technology •How it works – ITO conducts a continuous electrical current across the sensor – Finger touch alters the capacitance field – The resulting distortion is measured by circuits at each corner of the screen •Advantages: durability •Disadvantages: requires finger touch •Applications: retail, game/entertainment, industrial/financial Source: 3M Technical Materials © Corning Incorporated 2008 6 Current Tech Projected Capacitive becomes more popular due to iPhone, and can be used for both small and large panels •How it works – Consists of a sensor grid of micro-fine wires laminated between two layers of protective glass – Touch location calculated from changing electrical characteristics of the sensor grid – Can be installed behind other materials, e.g. vandal-resistant glass – Finger does not have to be in physical contact •Advantages: durability, environmental tolerance •Disadvantage: high cost •Applications: mobile phone, retail Source: Elo Technical Materials © Corning Incorporated 2008 7 Design Considerations for Cover Glass Technical Materials © Corning Incorporated 2008 8 Typical glass surface damage from “used”devices ~ 20 micron depth Impacts ~ 40 micron depth Scratches Scratch with Lateral Cracks Technical Materials © Corning Incorporated 2008 9 Surface damages cause glass failure Summary of Failure Analysis of Broken Devices (Field-returned and drop tested): Impact • Major cause of fracture –Impact damage 60 – Sharp impacts create flaws that cause failure 50 Scratch • Keys, pens, gravel, etc. 40 30 • Second major cause - Scratch-related damage – Fracture initiated from a flaw within the scratch 20 Other 10 • Over-stress alone does not cause failure 0 1st Qtr – Strengthened glass deflects substantially before failure • Devices do not have room for so much deflection – Failure stresses are never reached Impact event Scratch event Origin Depth of damage 15 mm Depth of scratch 25-40 mm Technical Materials © Corning Incorporated 2008 10 Design considerations 99 • Define “Design strength” 90 • Strength of brittle materials 50 Soda lime glass represented by Weibull statistics Gorilla 10 glass – Select low (1%?) probability of % Probability, Failure failure strength 5 – Apply a factor of safety 1 100 1000 Strength, MPa • Strength of glass decreases 700 600 only enough when damaged specimens for abrasion at tme of testing 500 – In-use strength measured by Unabraded 400 Abraded Strength 300 Corning Strength, MPa Strength, abraded 57 – Abrasion per ASTM C158 200 Corning 45 100 Corning • Input requirements from failure- IG3 IG3 Corning 31 0 18 NS mode analysis Glass and IX Condition Technical Materials © Corning Incorporated 2008 11 Requirements for glass in mobile devices 1. Tight Strength distributions 2. High retained (abraded) strength 3. Increased resistance to impact damage 4. Greater resistance to scratching Technical Materials © Corning Incorporated 2008 12 Gorilla™ Glass Technical Materials © Corning Incorporated 2008 13 What is Corning Gorilla™ Glass? • Alumino-silicate thin sheet glass – Capable of high strength and reliability when chemically tempered with an ion-exchange process • Formed using Corning’s proprietary fusion draw process – Highest quality of as-drawn glass sheets in the world – Thickness 0.7 mm –2.0 mm as drawn • Corning glass is ideal for display cover windows – Touch screens – Mobile phones – Other mobile electronic devices Technical Materials © Corning Incorporated 2008 14 Key benefits • Glass designed for deep, protective, ion-exchange layer • High strength and reliability • Ability to sustain impacts without damage • Retains high strength after use and abuse • Pristine glass sheet surface • Scalable sheet sizes for optimal throughput Technical Materials © Corning Incorporated 2008 15 Gorilla™ Glass combines unique capabilities Proprietary fusion Innovative glass forming process: composition superior surface, optimized for Gorilla Glass scalability, chemical reliability tempering Technical Materials © Corning Incorporated 2008 16 Fusion-formed for a pristine surface Fusion Lap & polish 10 nm 5 um 5 m Roughness Measurement Results Area 1 Area 2 RMS 0.29 nm 1.46 nm Ra 0.23 nm 1.13 nm Z-Range 4.23 nm 33.7 nm Technical Materials © Corning Incorporated 2008 17 What properties of glass provide these requirements? Flaw populations in the surface DOL DOL Competition Gorilla Cross section of a chip • Flaws, damages and scratches on the surface Competition Gorilla reduce strength Cross section of a scratch • Enveloping compression layer of Gorilla™ Glass provides tight strength distributions Competition Gorilla Technical Materials © Corning Incorporated 2008 18 Gorilla™ Glass –ideally suited for protective covers for mobile displays • Highest degree of chemical strengthening • Tightest strength distribution • Highly tolerant to in-use damage (high retained strength) • Highest impact resistance • Highest resistance to scratch Technical Materials © Corning Incorporated 2008 19 The ion-exchange process KNO3 bath Glass surface O2 Si Al glass Na: 0.97Å K:1.33Å Technical Materials © Corning Incorporated 2008 20 What is chemical strengthening? • Compressive stress and depth of layer (DOL) define the characteristics of chemical strengthening CS DOL • Stress equilibrium will induce TS a tensile stress in the center of the sheet • Overcoming the compressive stress at the crack tip is necessary to initiate failure Technical Materials © Corning Incorporated 2008 21 Gorilla™ Glass has the highest depth of layer (DOL) • Degree of chemical 80.0 E strengthening is the 70.0 A development of the I desired level of 60.0 compressive stress GorillaGorilla (CS) over desired 50.0 DOL m) m 40.0 • Gorilla Glass can achieve DOL DOL ( DOL (µm) DOL 30.0 greater than typical damages/flaws 20.0 depth 10.0 • Gorilla glass is designed for lower 0.0 stress relaxation, 300.0 400.0 500.0 600.0 700.0 800.0 900.0 Compressive stress (MPa) higher DOL and Compressive Stress (MPa) high CS Technical Materials © Corning Incorporated 2008 22 Gorilla™ Glass has the highest CS at given DOL 900 • The predicted CS at DOL = 15 Extrapolated 15 um and 25 um 800 DOL = 25 DOL is shown 700 600 • At deeper DOL, compressive 500 stresses are significantly lower 400 for the soda-lime Compressive Stress (MPa) Stress Compressive glasses Compressive Stress (MPa) Compressive Stress 300 E A I GorillaGorilla Technical Materials © Corning Incorporated 2008 23 Gorilla™ Glass –ideally suited for protective covers for mobile displays • Highest degree of chemical strengthening • Tightest strength distribution • Highly tolerant to in-use damage • Highest impact resistance • Highest resistance to scratch Technical Materials © Corning Incorporated 2008 24 Gorilla™ Glass has tighter strength distribution 99 90 • Gorilla Glass 50 A shows the highest overall Gorilla strength 10 Failure Probability, % Probability, Failure 5 1 100 1000 Strength, MPa Note: Edge strength is measured using 4-pt bend test Technical Materials © Corning Incorporated 2008 25 Gorilla™ Glass –ideally suited for protective covers for mobile displays • Highest degree of chemical strengthening • Tightest strength distribution • Highly tolerant to in-use damage • Highest impact resistance • Highest resistance to scratch Technical Materials © Corning Incorporated 2008 26 Flaws induced during in-service life • “In Use Flaws”can be simulated by abrading the surface – ASTM C158 • Measure strength after