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