摘要:
The invention relates to a method and to a device for producing a hologram as a security feature, a hologram and a security document provided with said type of hologram. The invention also relates to a method and to a device for verifying a hologram or a security document provided with said type of hologram. The invention further relates to a hologram having a watermark-type structure that reflects and/or deflects incident light at a reconstruction incident angle during the reconstruction at a reconstruction incident angle. Said hologram comprises at least two regions that reflects, at various large angular ranges, about the reconstruction incident angle, incident light in correspondingly different large angular ranges about the reconstuction incident angle.
摘要:
A method is disclosed for making holographic images by recording an array of pixels (202) which together form a two or three dimensional composite image. Each pixel corresponds to a sampling of just those rays which would pass through a given point (205) on the surface of an ordinary hologram. Every common type of hologram can be made by this method, including 2D/3D holograms, stereograms, and full color holograms. Each pixel is a white light viewable hologram generated by recording a small hologram near the narrowest part of a converging bundle of rays of coherent light (520), usually with each ray corresponding to one point on the object, and the rays in a pixel being confined to a horizontal plane intersecting the surface of the object.
摘要:
A beam (110) of coherent light is coupled into an array of light detectors (146, 148, 150, 152) using a beam splitter (120) for dividing the beam into a probe beam (102) and a pump beam (122) and a spatial light modulator (144) for varying the intensity of the probe beam (102) in a first direction perpendicular to the direction of propagation of the beam. A photorefractive element (134) is positioned to receive the modulated probe beam and the pump beam, the beams being oriented with respect to the photorefractive element (134) and with respect to each other such that photorefractive two-wave mixing within the photorefractive element (134) nonreciprocally transfers energy from the pump beam (122) to the modulated probe beam, which is then detected by the detector array (146, 148, 150, 152). A first lens system (138, 140) may be positioned in the path of each probe beam (102) between the beam splitter (120) and the spatial light modulator (144) for expanding each probe beam (102) in the first direction, while a second lens system (130, 132) may be positioned in the path of each pump (122) beam between the beam splitter (120) and the photorefractive element (134) for expanding each pump beam (122) in the first direction.
摘要:
The invention relates to a method and to a device (1) for producing a hologram, in particular as a security feature, and to a hologram. The invention further relates to a method for producing an individualised hologram in which coherent light (8) is generated and is modulated spatially according to an individualised pattern. Said modulated light (11) is used, preferably, to expose a hologram in such a manner that the holographic recording material (4) is radiated by the coherent modulated light (11) and at least one part of the coherent light (11) is reflected or refracted on a holographic master (2) in order to interfere with the coherent light (11) radiating the holographic recording material (4) such that the hologram in the recording material (4) is exposed. The invention is characterised in that, by means of the hologram master (2), a background pattern stored in the hologram master (2) is stamped on the modulated coherent light comprising the coded individualised information when reflecting or refracting on the hologram master (2), such that the background pattern is stored together in the hologram with the individualised information.
摘要:
There is provided an information recording device for recording the recording information on a recording medium having a recording surface where recording can be performed optically. The information recording device includes a laser light source and a conversion optical system for converting the laser beam emitted from the laser light source into a planar laser beam having an optical flux cross section extending linearly. The information recording device further includes: one-dimensional space modulation means (3) for subjecting the planar laser beam to one-dimensional space modulation according to the recording information; and a recording optical system for applying the planer laser beam subjected to the spatial modulation, as a signal light (Ls) to the recording surface while applying a reference light (Lr) to the recording surface.
摘要:
There is provided an information recording device for recording the recording information on a recording medium having a recording surface where recording can be performed optically. The information recording device includes a laser light source and a conversion optical system for converting the laser beam emitted from the laser light source into a planar laser beam having an optical flux cross section extending linearly. The information recording device further includes: one-dimensional space modulation means (3) for subjecting the planar laser beam to one-dimensional space modulation according to the recording information; and a recording optical system for applying the planar laser beam subjected to the spatial modulation, as a signal light (Ls) to the recording surface while applying a reference light (Lr) to the recording surface.
摘要:
The invention relates to a method and a device for producing an individualized hologram, wherein a light beam (3) is generated. According to the method, the light beam (3) is individually modulated in a spatial light modulator (5), a holographic recording material (13) is arranged relative to a holographic master (23) and the individually modulated light beam (3') is guided in such a manner that at least part of the individually modulated light beam is refracted and/or reflected on the holographic master (23) and an interference pattern representing the individualized hologram is produced in the holographic recording material (13). The individually modulated light beam (3') is displaced relative to the holographic recording material (13) and the holographic master (23) to scan the entire holographic master (23), the recording material (13) being arranged so as to rest on a cylindrical drum (15) or a cylindrical drum segment and the drum (15) being rotated about a drum axis (27) of the drum (15) or the drum segment during scanning of the holographic master (23).