Patent ID: 8530786
Filing Date: 2013-09-10
Classification: B23K,B28D,B29C,B29K,B81B,B81C,C03B,C03C,Y10T

Abstract:
1. A method for generating visible patterns of laser-modified features below the surface of a transparent material, said patterns having controllable contrast and visibility, said method comprising: forming a plurality of lines at different depths within the material using tightly focused ultrashort pulse laser outputs, said tightly focused outputs having controllably varied focal points and sufficient fluence so as to create regions of material modification at said different depths below said surface; controlling the roughness of said lines by controlling parameters of said laser; and illuminating said lines using light propagating generally perpendicular to said lines, wherein said patterns are clearly visible to the unaided eye when illuminated from the perpendicular, and substantially invisible to the unaided eye under ambient light and at a time when said step of illuminating is suspended.