Patent ID: 7602409

Claim:
Method for forming a 2-dimensional code by laser marking to execute laser marking the 2-dimensional code on a work comprising: a generated color acquiring process for acquiring the generated color information for judging whether the color of a portion on which laser beam is applied is brighter or darker than the color of portion on which laser beam is not applied for each the work, a code symbol acquiring process for generating or acquiring the code symbol of the 2-dimensional code consisting of array pattern that the dark and bright color unit cells are arranged in matrix state taking the code color and the background color of the 2-dimensional code as a dark color and a bright color, respectively, and a laser marking process for executing laser marking by applying the laser beam on the area in which the bright color unit cells are arranged in the code symbol as well as by applying the laser beam on a margin area having a predetermined width that is attached to the periphery of the code symbol under the condition that the color of the portion on which the laser beam is applied is judged to be brighter than the color of the portion on which the laser beam is not applied based on the generated color information.