| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a diffraction grating recording medium capable of enhancing the forgery prevention property and also the reliability of security. <P>SOLUTION: A diffraction grating recording medium 3 comprises: a first recording part 31 including a first observation image unit cell 11a with a first observation image optical diffraction structure and a second observation image unit cell 12a with a second observation image optical diffraction structure; a second recording part 2G including a first hidden image unit cell 2R with a first hidden image optical diffraction structure and a second hidden image unit cell with a second hidden image optical diffraction structure; and a second recording part 2B including a third hidden image unit cell with a third hidden image optical diffraction structure. A lattice pitch of the first observation image unit cell 11a and the second observation image unit cell 12a is a wavelength of visible light or more, and a lattice pitch of the first hidden image unit cell 2R, a lattice pitch of the second hidden image unit cell 2G and a lattice pitch of the third hidden image unit cell 2B are a wavelength of visible light or less. <P>COPYRIGHT: (C)2013,JPO&INPIT |
