Butchi Reddy Vaddi

P-197L: Late-News Poster: Impacts of Glass Substrate and Frit Properties on Sealing for OLED Lighting

Glass frit seal with localized heating using near infrared laser can provide long-term hermeticity and good mechanical strength for OLEDs. In this report, some general characteristics of the frit sealing process are first discussed. Then the impacts offrit and glass substrate properties, such as CTE and strain points on the seal, will be presented. It is found that CTE of the frit may not match with that of glass substrates used for lighting application. The optimal CTE values of glass substrate for OLED lighting and frit are presented.

CO2 laser scribe of chemically strengthened glass with high surface compressive stress

Chemically strengthened glass is finding increasing use in handheld, IT and TV cover glass applications. Chemically strengthened glass, particularly with high (>600MPa) compressive stress (CS) and deeper depth of layer (DOL), enable to retain higher strength after damage than non-strengthened glass when its surface is abraded. Corning Gorilla® Glass has particularly proven to be advantageous over competition in this attribute. However, due to high compressive stress (CS) and Central Tension (CT) cutting ion-exchanged glass is extremely difficult and often unmanageable where ever the applications require dicing the chemically strengthened mother glass into smaller parts. We at Corning have developed a CO2 laser scribe and break method (LSB) to separate a single chemically strengthened glass sheet into plurality of devices. Furthermore, CO2 laser scribe and break method enables debris-free separation of glass with high edge strength due to its mirror-like edge finish. We have investigated laser scribe and break of chemically strengthened glass with surface compressive stress greater than 600 MPa. In this paper we present the results of CO2 scribe and break method and underlying laser scribing mechanisms. We demonstrated cross-scribe repetitively on GEN 2 size chemically strengthened glass substrates. Specimens for edge strength measurements of different thickness and CS/DOL glass were prepared using the laser scribe and break technique. The specimens were tested using the standard 4-point bend method and the results are presented.

P‐184L: Late‐News Poster: Transient Thermal Stress Modeling of the Laser Frit Sealing Process

The frit laser sealing process has been modeled through the finite element method. Transient thermal stress results have been used to explain experimental observations, and to provide further processing recommendations and design guidelines. The results explained why high CTE glass is hard to seal. A simple and practical solution is demonstrated to reduce the transient thermal stress by elevating ambient temperature during high CTE glass sealing.