Method and apparatus for reading and marking a small bar code on a surface of an item

摘要: An apparatus and method for reading a bar code marked on surface of an item, such as semiconductor wafer, improved marking the easily decipherable system are disclosed. The comprises collimated light source, beamsplitter, first lens system, second image screen detector. steps illuminating by directing perpendicular to surface, magnifying coaxial reflected beam, projecting beam projected with making marks rotating diamond impregnated nickel blade, decreasing relative distance between blade until contacts increasing repeating this process desired number bars obtained. includes characters comprised wide narrow spaces patterned after Roman numeral system.