Abstract:
The nature of a volume hologram limits its use in security and sensing applications. Accordingly, a volume hologram (1) segregated into a first (2) and second (3) region recording a first and second image, respectively, and wherein the second region (3) is responsive to stimulus while the first region is protected physically from stimulus is provided. Also provided is a volume hologram with a functional cover disposed thereon to regulate how the volume hologram interacts with the stimulus when in the presence of stimulus. A volume hologram with a removable cover disposed thereon to permit a first recorded image to be viewed, to protect the volume hologram from physical damage, to prevent the volume hologram from interacting with the stimulus, and to be removed, thereby permitting the volume hologram to interact with the stimulus is provided as well. In these ways, the usability of volume holograms in security and sensing applications is increased.
Abstract:
A method for transferring a holographic design on a multilayer polyethylene film having DSC (Differential Scanning Calorimeter) melting point less than or equal to 119 degrees centigrade is provided. The holographic film has higher interlayer bond strength against PET (polyethyleneterephthalate) or BOPP (Biaxially oriented polypropylene) enabling surface printing on the other side layer of the multilayer of the holographic film. The films have good oxygen and moisture barrier properties and therefore can be used be used for manufacturing attractive holographic tubes for food product, toothpaste, cosmetics etc.
Abstract:
In a coding method for the encryption of information worth protecting on a holographic data storage medium, an item of information (I; I 1 , I 2 ) to be encrypted is converted into a graphic data image (D 1 , D 2 ), which is in turn converted into a hologram in order to write the holographic data storage medium (4) therewith. The invention provides for the hologram to be changed graphically before the writing of the holographic data storage medium (4). As a result of the manner in which the hologram is changed graphically, encryption which is less susceptible to faults is achieved in a simple way, which presents increased resistance to a parallelized brute force attack.
Abstract:
A 3D content generation system comprising a content generating party that generates 2D content and sends that content to a remote intermediary. The remote intermediary processes the content to facilitate subsequent holographic reconstruction and sends the processed content to a holographic display device which locally generates a 3D holographic reconstruction of the content. An advantage is that 2D content may be processed remotely to provide 3D holographic content.
Abstract:
A new type of FT lens is provided that improves phase conjugation in holographic data systems. This type of FT lens has a uniquely large isoplanatic patch. This enables relaxed assembly tolerances, asymmetric reader/writer architectures, and compensation for tilted plate aberrations in the media.
Abstract:
Methods for evaluating an optically variable device ("OVD") or optically variable media ("OVM") are disclosed. The methods include the steps of applying light of a single wavelength from a calibrated light source to the OVD or OVM; measuring the light diffracted by the OVD or OVM with an integrating sphere; measuring the total incident light on the OVD or OVM; and calculating a diffraction efficiency for the OVD or OVM at the single wavelength based on the measurement of light diffracted and the measurement of total incident light.
Abstract:
Le procédé d'authentification comporte : une étape de génération d'un nombre aléatoire (105); une étape de génération d'un horodatage (115); une étape de génération d'une première clé secrète (120); une étape de troncature de code d'authentification de message mettant en oeuvre ladite première clé secrète (125); une étape d'encryption symétrique du nombre aléatoire, de l'horodatage et de la troncature (135), en mettant en oeuvre une deuxième clé secrète (130) pour produire un code d'authentification (145). Préférentiellement, au cours de l'étape de génération d'un nombre aléatoire, on met en oeuvre un générateur quantique (100). Préférentiellement, au cours de l'étape de troncature, on génère un authentifiant de message cryptographique en mettant en oeuvre la première clé secrète. Préférentiellement, au cours de l'étape d'encryption symétrique du nombre aléatoire, en mettant en oeuvre la deuxième clé secrète, on produit, en outre, un condensât (140).
Abstract:
Described is an optical device for combining multiple light sources (102) in an optical projection system. One embodiment of the optical device includes at least two light sources having first and second wavelengths, and an optical element (106) for substantially diffracting the first and second wavelengths of the two light sources and combining them into a single beam of light (110).
Abstract:
A method for printing a binary hologram on a manufactured product comprises the provision of a stamp with a pattern corresponding to the hologram (30). The product is initially coated with a metal layer. The stamp is inked with a masking solution (40) and pressed against the manufactured product (50). Then, the hologram print is obtained by selective etching of parts of the metal layer which are not masked (60). The method is adapted for printing holograms on optical lenses.
Abstract:
A security mark having multiple optically orthogonal coaligned bar codes is produced using a reflection hologram visible substantially at only a first wavelength that is layered over a wavelength sensitive filter, which blocks light transmission at the first wavelength but transmits light at a second wavelength, and having beneath it an additional bar code visible through the hologram and the wavelength sensitive filter at the second wavelength. A validation means reads multiple holographic bar codes with light at the first wavelength by illuminating the hologram separately from multiple directions, and further reads the bar code beneath the wavelength sensitive filter by illuminating the mark with light of the second wavelength. By suitable choice of multi-directional and mufti-wavelength illumination, multiple coaligned bar codes may be read in the same physical location with no mutual interference.