Patent ID: 7594613

Claim:
A 2-dimensional code formation method comprising: a step of specifying a fixed code size for a 2-dimensional code regardless of an amount of storage information to be written in said 2-dimensional code; a step of specifying storage information to be written in said 2-dimensional code; a step of calculating cell size for a unit cell of said 2-dimensional code providing storage of said storage information in said 2-dimensional code having said specified code size; a step of specifying the dot step size or number of dots n×m (where n and m are natural numbers) to be arranged vertically and horizontally inside said unit cell; a step of creating laser-marking information for forming said 2-dimensional code having said specified code size, based on said code size, said storage information, said cell size and said dot step size or number of dots, wherein said laser-marking information includes at least dot coordinate information; and a step of laser marking said 2-dimensional code having said specified code size by laser dot marking to uniformly arrange dots vertically and horizontally in an n×m matrix array inside said unit cell based on said dot coordinate information of said laser-marking information by irradiating a laser beam directly on a material to be marked, wherein said dots are beam spots generated by irradiating a laser beam.