| 摘要 |
PROBLEM TO BE SOLVED: To provide a diffraction grating or a hologram capable of improving such defects that to be "disordered" and to "strongly" diffract light by generating interference of light in accordance with "periodicity" of ruggedness are contradictory to each other when enhancing a forgery prevention effect according to disorderliness of hidden information and that a large fluctuation/irregularity is caused in brightness or tone of color of the diffraction image or hologram image when visually observing the whole of diffraction grating or hologram prepared by the technology, in regard to the diffraction grating or hologram having the hidden information according to a rugged structure incorporated as information difficult to ascertain by visible sight in various kinds of picture patterns used for security application. SOLUTION: Diffraction grating lines each of which is formed by arranging prescribed information as the hidden information into a column of rugged shape are arrayed regularly in parallel with a period of length double the visible light wavelength and, thereby, the interference of the diffractive light of the diffractive grating or hologram is intensified to provide a diffractive image without fluctuation or irregularity. COPYRIGHT: (C)2010,JPO&INPIT |
