Patent ID: 8257603

Claim:
A method for laser patterning a partial depth surface portion of a glass body, said method comprising: providing a laser, said laser having a laser output beam at a laser wavelength λ; providing a glass body having an optical density at of at least 1.5 per cm at said wavelength λ; directing said laser output beam along an impinged path on the surface portion of said glass body to form a swell in said surface portion of said glass body by heating said surface portion of said glass body; cooling said heated surface portion of said glass body; and etching said surface portion of said glass body, wherein said surface portion of said glass body is heated to a target temperature T above a strain point of said glass body at a heating rate HR to form said swell along said impinged path of said laser output beam, said heating rate HR is a function of a target temperature T and an exposure time of said laser output beam along said impinged path and is controlled such that an exposure time required to reach a target temperature above a softening point of said glass does not require a power density that would lead to laser ablation of said surface portion of said glass body along said impinged path, said surface portion of said glass body is cooled to a temperature below said strain point of said glass body to induce regions of localized stress of at least 300 psi in said unablated surface portion of said glass body along said impinged path of said laser output beam and create a pattern of localized laser-induced stress in said glass body, said regions of induced localized stress penetrate said glass body below said surface portion of said glass body and have larger dimensions than the swell formed in said surface portion of said glass body along the path of the laser output beam, and said unablated surface portion is etched in said state of induced localized stress to form a patterned glass body.