DIFFRACTION GRATING PATTERN CONSISTING OF VOLUME PHASE TYPE HOLOGRAPHIC GRATING AND ARTICLE HAVING THE SAME

摘要

PURPOSE: To improve the security and prevent the article from being forged by an optical technique, and to enable anybody to easily ascertain the truth of the article. ;CONSTITUTION: In the diffraction grating pattern formed by arranging plural dots of fine diffraction gratings on the surface of a plane substrate 1, volume phase type holographic gratings 2 which have angle dependency and wavelength dependency are formed as the fine diffraction gratings, the spatial frequency and angle of the diffraction gratings are varied by the dots of the respective fine diffraction gratings, and a real image reproduction type hologram is formed as at least one of the diffraction gratings at need.;COPYRIGHT: (C)1994,JPO&Japio