Laser marking system

Abstract

A laser energy microinscribing system, comprising a semiconductor excited Q-switched solid state laser energy source; a cut gemstone mounting system, allowing optical access to a mounted workpiece; an optical system for focusing laser energy from the laser energy source onto a cut gemstone; a displaceable stage for moving said gemstone mounting system with respect to said optical system so that said focused laser energy is presented to desired positions on said gemstone, having a control input; an imaging system for viewing the gemstone from a plurality of vantage points; and a rigid frame supporting said laser, said optical system and said stage in fixed relation, to resist differential movements of said laser, said optical system and said stage and increase immunity to vibrational misalignments. The laser energy source is preferably a semiconductor diode excited Q-switched Nd:YLF laser with a harmonic converter having an output of about 530 nm. The system may further comprise an input for receiving marking instructions; a processor for controlling said displaceable stage based on said marking instructions and said imaging system, to selectively generate a marking based on said instructions and a predetermined program; and a storage system for electronically storing information relating to images of a plurality of workpieces. A secure certificate of authenticity of a marked workpiece is also provided.

Description

FIELD OF THE INVENTION [0001] The present invention relates to the field of inscribing indicia on a surface of gemstones, and more particularly to a system employing a Q-switched pulse laser for forming markings on a portion of a gemstone. BACKGROUND OF THE INVENTION [0002] A known system, as described in U.S. Pat. No. 4,392,476, incorporated herein by reference, for inscribing diamonds includes a Nd:YAG (1.06 μm, frequency doubted) Q-switched laser which marks diamonds by graphitizing the surface at a laser focal point. The beam position is computer controlled to create overlapping treated regions. The accuracy of known embodiments of this system are limited by vibration and laser steering system accuracy. [0003] U.S. Pat. No. 4,667,172, incorporated herein by reference, describes a laser beam diamond inscribing system, which provides a Q-switched flashlamp pumped YAG laser (1.06 μm, frequency doubled) with the diamond mounted on a computer-controlled positioning table for inscribi...

AI Technical Summary

Benefits of technology

[0013] The process according to the present invention typically achieves a positioning accuracy of about ±1 micron. The laser and translatable mounting stage are compact and are preferably rigidly mounted on a common platform allowing sufficient common mode vibration immunity so that only standard vibration damping need be employed rather than extraordinary damping. Therefore, simple and small passive vibration isolation mounts for the platform or chassis are employed, rather than requiring active vibration suppression systems as in known systems.

[0073] It is a still further object of the invention to provide a laser energy microinscribing system, comprising a semiconductor excited Q-switched solid state laser energy source; a cut gemstone mounting system, having an aperture; an optical systems for focusing laser energy from the laser energy source, through said aperture onto a cut gemstone; a displaceable stage for moving said gemstone mounting system with respect to said optical system so that said focused laser energy is presented to desired positions on said gemstone, having a control input; an imaging system for viewing the gemstone from a plurality of vantage points; and a rigid frame supporting said laser, said optical system and said stage in fixed relation, to resist differential movements of said laser, said optical system and said stage and increase immunity to vibrational misalignments.

Problems solved by technology

The accuracy of known embodiments of this system are limited by vibration and laser steering system accuracy.

Thus, repositioning to form complete characters or graphics is unnecessary.

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