A data carrier printed by line intaglio having a halftone image represented by irregular line structures in the manner of an engraving. The upper shaft, the lower shaft, and the input shaft can rotate together, and the input shaft and the output shaft are relatively rotatably coupled to each other via a torsion bar. The document case has a top cover and a bottom housing which matingly engages with one another by protruding notches and a corresponding recess. The transparent pattern is arranged between the layers of the antireflection film, or above or below the antireflection film. In another embodiment, a method effectuates scan-based testing of circuits.