Laser marking system

A focus sensing unit in a gemstone marking system for sensing a relative position of a marking surface of the gemstone and a focal plane of a laser beam incident on said marking surface, said focus sensing unit comprising:

• (a) an optical source adapted to emit an optical beam toward the marking surface;
• (b) a side camera that is both substantially horizontal with respect to the center of the gemstone when in the desired position and substantially perpendicular to the laser beam passing through a focusing lens, for measuring an illumination of the marking surface by the optical beam, the camera being adapted to produce a signal in dependence on a relative position of the marking surface and the focal plane of the laser beam;
• (c) a signal processing unit coupled to said camera for receiving said signal and producing data corresponding to the relative position of the marking surface and the focal plane of said laser beam;
• and
• (d) a mechanism, coupled to said signal processing unit, which automatically controls the position of the gemstone in response to said data, to translate the gemstone relative to said focal plane of said laser beam to automatically control the position of the marking surface of the gemstone relative to the focal plane in response to said data received from said signal processing unit.

A focus sensing and focusing unit in a gemstone marking system for sensing a relative position of a marking surface of a gemstone and a focal plane of a laser beam incident on said marking surface, and for adjusting the focal plane with respect to the gemstone surface, said unit comprising:

• (a) a light source adapted to emit an optical beam directed toward said marking surface,
• (b) a side camera that is both substantially horizontal with respect to the center of the gemstone when in the desired position and substantially perpendicular to the laser beam passing through a focusing lens, said camera being adapted to measure an interaction of the optical beam and the marking surface, the output of said camera being dependent on a relative position of the marking surface of the gemstone and the focal plane of said laser beam, and
• (c) a signal processing unit coupled to said camera for receiving said output and producing data corresponding to the relative position of the marking surface of the gemstone and the focal plane of the laser beam;
• and
• (d) a mechanism for automatically changing a position of the gemstone to substantially align the focal plane of the laser beam with the marking surface in response to said data.