Patent ID: 8341976

Claim:
A method of separating a strengthened glass sheet, the method comprising: providing the strengthened glass sheet, the strengthened glass sheet having a first surface and a second surface, wherein: each of the first surface and the second surface has a strengthened surface layer under a compressive stress and extending from the surface to a depth of layer, and wherein the strengthened glass sheet has a central region under tensile stress; and the strengthened glass sheet comprises an aluminoborosilicate glass material having at least one alkali metal oxide modifier, and the ratio Al 2 ⁢ O 3 ⁡ ( mol ⁢ ⁢ % ) + B 2 ⁢ O 3 ⁡ ( mol ⁢ ⁢ % ) ∑ ⁢ modifiers ⁢ ⁢ ( mol ⁢ ⁢ % ) > 1 ; forming at least one laser-induced damage line in the central region at a predetermined depth below the first surface by irradiating the strengthened glass sheet with a nanosecond pulsed laser, wherein the nanosecond pulsed laser is operated at a power of less than about 4W; and initiating and propagating a crack to separate the strengthened glass sheet into at least two pieces along the at least one damage line.