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AssigneeDai Nippon Printing Co., Ltd.
InventorsShigehiko Tahara, Shinichi Kurokawa, Norio Takahashi, Ryuji Horiguchi, Morito Sakai, Akira Hayakawa, Shinpei Komaki
Estimating the term…
The invention is directed to an information-recorded medium with easily selectable and identifiable items of information, which is virtually protected against forgery and has enhanced security against some improper use, and a method for reading such a medium. This information-recorded medium 1 includes a substrate 2 and a layer 3 with information recorded thereon by the printing of infrared absorbing ink, said layer 3 being provided on the surface of the layer 2. The printed layer 3 is provided thereon with a relief hologram-recorded layer 7 through an adhesive layer 4, said hologram-recorded layer 7 being built up of a reflecting layer 5 transparent to the infrared region and a relief hologram-formed layer 6 provided on the surface of the reflecting layer 5. For reading, the hologram-recorded layer 7 is reconstructed by visible light, while the printed layer is reconstructed by infrared light, and the medium 1 is identified on the basis of the thus reconstructed information.
An information-recorded medium which includes a layer with a hologram recorded thereon that is composed of a hologram having interference fringes recorded in a transmittance profile or refractive index profile form in a thickness direction of the optical recording material, wherein spacings between interference fringes are made wide or narrow in a portion or portions of the hologram so as to conform to additionally written information, thereby making a wavelength reconstructed by the resultant portion different from that of another portion of the hologram.
A medium having information recorded thereon, comprising a first layer with a hologram or a diffraction grating recorded thereon and a second layer with information recorded thereon by printing, each layer having at least an information recorded thereon, wherein
Dependencies are inferred from the claim text.