Patent ID: 9533527
Date: 2017-01-03
CPC Classifications: B42D,G02B,G03H

Claim:
1. A diffraction grating recording medium, characterized by comprising: a first recording region including viewing image unit cells having a light diffraction structure, and a second recording region including hidden image unit cells having a light diffraction structure, wherein: said viewing image unit cells of said first recording region have a grating pitch more than a wavelength of visible light, said hidden image unit cells of said second recording region have a grating pitch less than the wavelength of visible light, said second recording region is smaller than said first recording region, said second recording region is provided in a parallel straight line form with respect to said first recording region, said viewing image unit cells form together an original image including a first pattern region and a second pattern region, said hidden image unit cells form together a hidden image that is identifiable under a specific viewing condition alone, said viewing image unit cells include a first viewing image unit cell corresponding to said first pattern region and a second viewing image unit cell corresponding to said second pattern region, in said first recording region, a portion of said original image corresponding to said first pattern region is formed by said first viewing image unit cell and a portion of said original image corresponding to said second pattern region is formed by said second viewing image unit cell, and in said second recording region, a portion thereof corresponding to said hidden image is formed by said hidden image unit cells, and a portion thereof that does not correspond to said hidden image is formed by cells selected from blank cells, said first viewing image unit cells and said second viewing image unit cells, at least are formed in said first recording region.