Laser-scribing of chemically strengthened glass

摘要

A method is disclosed for scribing a contained crack or vent in a chemically strengthened glass sheet. The glass has shallow surface regions under compressive stress, bounding a central region under tensile stress. The vent is formed by rapidly bulk-heating the glass, using radiation from a carbon monoxide laser, to a depth just below a surface compressive region and extending marginally into the tensile stress region then rapidly cooling the heated region with a water mist spray. The glass sheet can be subsequently divided along the vent by application of mechanical or thermal stress.

主权项

1. A method of scribing a sheet of chemically strengthened glass for subsequent separation into one or more parts, the chemically strengthened glass sheet characterized as having opposite surface zones under compressive stress, with a central zone between the surface zones being under tensile stress, the method comprising:
using a beam of laser-radiation from a carbon monoxide (CO) gas laser directed onto a surface to be scribed, and while translating the laser-radiation beam with respect to a surface of the chemically strengthened glass sheet, heating the glass sheet to a depth extending below the surface zone, and extending partially into the central zone; and directing a coolant spray onto the surface at a predetermined distance behind the laser-radiation beam in the translation-direction thereof, thereby cooling the heated surface-zone and creating a contained crack following the translation-direction of the laser-radiation beam, the crack having a depth extending below the surface zone partially into the central zone; and wherein the beam of laser radiation emitted from the laser has an about Gaussian intensity distribution and wherein the beam is transmitted through a sealed enclosure containing air having a predetermined controlled humidity selected to convert the Gaussian intensity distribution to a flat-top intensity distribution, wherein the beam having a flat-top intensity distribution is directed to the surface to be scribed.