Laser marking system and method for temporarily marking a surface

A system for placing a temporary mark on a surface, said surface coated with a light reactive, color-forming chemical mixture, said mixture soluble in a solvent that is nonreactive with said surface, said system comprising:

• means for coating at least a portion of said surface with said light reactive, color-forming chemical mixture;
• laser means for generating a collimated beam of light for photo exposing said chemical mixture coating, said laser means including a laser and gradient index lens means for modifying said collimated beam of light to manifest an airy disk diffraction pattern including a central bright spot surrounded by bright and dark rings, said central bright spot including more than 50% of energy manifested by said collimated beam;
• means for scanning said collimated beam across said coated surface so as to expose a portion thereof to a scanned said central bright spot so as to create a color change in said coated surface coincident with a path taken by said scanned central bright spot;
• and,
• means for applying said solvent to said coated surface subsequent to a period of use, whereby said chemical mixture coated on said coated portion is removed from said surface.

A method for temporarily marking a surface, comprising the steps of:

• providing a light-reactive color-forming chemical mixture, said mixture being soluble in a liquid solvent that is non-reactive with said surface;
• coating at least a portion of said surface with said mixture;
• providing a laser means for generating a collimated beam of light, said laser means including a laser and lens means for adapting said collimated beam of light to manifest an airy disk diffraction pattern, said diffraction pattern having a central bright spot surrounded by alternating bright and dark rings, said central bright spot exhibiting a diameter which does not exceed a predetermined diameter at a distance from said laser means between a minimum distance and a maximum distance;
• providing a means for scanning said collimated beam of light across said coated surface;
• positioning said laser means and said means for scanning at a predetermined distance from said surface, said predetermined distance being between said minimum distance and said maximum distance;
• operating said laser means to generate said collimated beam of light;
• scanning said collimated beam of light in a path across said coated portion of said surface, said coated mixture being exposed to said central bright spot upon said scanning, said coated mixture manifesting a color change upon said exposure at points of incidence of said central bright spot on said coated mixture along said path, whereby said surface is marked;
• and,
• applying said solvent to said coated surface subsequent to a period of use, whereby said coated mixture is removed from said surface.

A system for temporarily marking a surface, comprising:

• means for coating at least a portion of said surface with a light-reactive color-forming chemical mixture, said mixture being soluble in a liquid solvent that is non-reactive with said surface;
• laser means for generating a collimated beam of light, said laser means including a laser and lens means for adapting said collimated beam of light to manifest an airy disk diffraction pattern, said diffraction pattern having a central bright spot surrounded by alternating bright and dark rings, said central bright spot exhibiting a diameter which is less than a predetermined diameter at a distance from said laser means between a minimum distance and a maximum distance;
• means for scanning said collimated beam of light in a path across said coated portion of said surface;
• and,
• means for applying said solvent to said coated surface subsequent to a period of use, whereby said chemical mixture coated on said coated portion is removed from said surface.