Abstract: A method of conducting a promotional contest by providing a portal that establishes a field for detecting the presence of a field-disturbing element, providing packages respectively having and lacking a concealed field-disturbing element, and distributing the packages randomly to different individuals who carry the packages past the portal so that a package with a field-disturbing element causes the portal to produce a signal indicating a winner of the contest. A can for beverages or the like having a field-disturbing element concealed thereon, for use in such a promotional contest. The element may be mounted in a peelable foil closure member covering an aperture in the can lid.

Abstract: A metal can for holding a carbonated or otherwise pressurized beverage or the like, having a rigid metal lid formed with an aperture, and a flexible closure member extending over the aperture and peelably bonded to the lid, the closure member including a portion that undergoes an irreversible change in appearance upon bending and is disposed to be bent by peeling of the closure.

Abstract: A method of conducting a promotional contest by providing a portal that establishes a field for detecting the presence of a field-disturbing element, providing packages respectively having and lacking a concealed field-disturbing element, and distributing the packages randomly to different individuals who carry the packages past the portal so that a package with a field-disturbing element causes the portal to produce a signal indicating a winner of the contest. A can for beverages or the like having a field-disturbing element concealed thereon, for use in such a promotional contest. The element may be mounted in a peelable foil closure member covering an aperture in the can lid.

Abstract: Porous membranes incorporating porous anodic films are disclosed. The membranes, which may be used as filters, gaseous diffusion media, dialysis membranes, etc., are produced by porous anodizing aluminum or other porous anodizable metal, creating a weakened stratum in the resulting porous anodic film (e.g. by a voltage reduction procedure during the anodizing step), attaching a support to the porous anodic film and separating the film along the weakened stratum. If the support is perforated the resulting structure is suitable as a separation device. If imperforate, the support can subsequently be perforated, if required, or replaced by a perforate support or supporting structure. The resulting structure has a non-metallic imperforate or perforated supporting layer (made, for example of plastic or ceramic) or other supporting structure, reinforcing a porous anodic film in which the pores completely penetrate the film.

Abstract: Optical interference structures incorporating porous films are disclosed. These structures are capable of exhibiting a color by interference effects caused by the interference of light reflected from various layers within the structure. Basically, the structures comprise a reflective substrate, a porous transparent dielectric film on the substrate and at least one semi-transparent layer supported by the porous dielectric film. The structure is such that there are at least two reflective surfaces separated by an optically thin porous layer of the dielectric film. These structures can be formed by several methods, but the most convenient involves the porous anodization of a substrate metal (e.g. aluminum) to form the dielectric film and the deposition of a semi-transparent metal layer within the pores or on the film surface. The structures can be made inexpensively and are capable of generating strong and, if desired, dichroic colors. The porous nature of the film can also be exploited to create color shifts.

Abstract: A bilayer oxide film which comprises a preferably porous layer containing aluminum oxide and a non-porous layer comprising an oxide of a valve metal, e.g. tantalum. The layers are integral. The film is produced by forming a coating of aluminium or an anodizable aluminum alloy on a valve metal (or alloy), anodizing the resulting structure in an electrolyte (preferably one capable of converting the aluminum (or alloy) to a porous oxide film) in the presence of an adhesion-reducing agent (e.g. fluoride ions) that makes the resulting anodized bilayer film easily detachable from the remaining valve metal. The bilayer film is then detached from the valve metal, e.g. by adhering a flexible plastic film to the bilayer and using the film to peel off the bilayer from the valve metal. The resulting bilayer can be used for a variety of purposes, e.g. as a vapor or oxygen barrier useful for packaging, or as a coating containing magnetic particles used to make a magnetic recording medium.

Abstract: A process for producing a released film made of at least two layers, one or more of which has been formed by a vapor deposition technique. The process involves anodizing a metal substrate comprising a valve metal or valve metal alloy to form an anodic oxide layer on the substrate, the anodization being carried out in the presence of an adhesion-reducing agent (e.g. fluoride) which makes the anodic layer detachable from the valve metal, coating the anodic layer with one or more layers of desired materials by a vapor deposition technique (e.g. sputtering or vacuum evaporation, etc.) to form a film of desired structure which is releasable from the metal substrate, and then detaching the releasable film from the metal substrate. The film can, if desired, be transferred to another substrate by attaching the other substrate to the releasable film before the releasable film is detached from the metal substrate.

Abstract: The invention relates to a laminated tamper-evident structure which exhibits an irreversible color change upon delamination. The structure includes a laminate of at least two layers capable of generating a color by a light interference and absorption phenomenon that requires direct and intimate contact between an adjacent two of the layers. The strength of attachment among the layers of the laminate is such that the laminate can be uniformly and reliably peeled apart at the interface between the adjacent two layers. An overlying flexible strip of transparent or translucent material is adhered to the laminate to facilitate the peeling operation. Upon peeling apart the laminate, the generated color is irreversibly lost, thus providing evidence that the structure has been tampered with. The structure can be incorporated into a variety of closable articles or products to provide evidence of opening or tampering.

Abstract: A thin film diagnostic device capable of detecting the presence of a specific organic material in a sample solution. The device comprises a layer of an anodizable color-generating metal (e.g. tantalum), a porous anodic film containing aluminum oxide overlying the color generating metal, and a reagent capable of binding with the specific organic material forming a coating on the anodic film. The porous anodic film and the coating have a combined thickness such that a color change is produced when the specific organic material binds to the reagent. The device can be used to test the biological or synthetic products in samples taken from patients or other sources.

Abstract: A process for producing a two phase metal/oxide film. The process comprises forming a porous oxide film on a substrate, introducing a weakened stratum into the oxide film so that the film (or at least an outer part of the film) can be subsequently detached along the weakened stratum, depositing a metal on and/or within the pore of the film, and detaching at least the outer film part from the substrate. The detached film so produced can be used for many purposes depending on the film thickness, position of the metal deposits on or with the pores etc. Examples include optical interference devices, magnetic media, coatings for plastics and paper, etc.

Abstract: A process for coating a packaging film with a transparent barrier coating. The process starts with a metal substrate made of, or having a surface coating of, a valve metal or valve metal alloy. The metal substrate is anodized to form an anodic film of the valve metal on the metal substrate. The anodic film is made readily detachable from the metal by carrying out the anodization step in the presence of an adhesion-reducing agent, e.g. a fluoride. The packaging film is then attached to the anodic film and the anodic film is detached from the metal. The transferred anodic film forms a thin dense oxide coating on the packaging film that acts as a barrier against oxygen and moisture transport. The invention can be used for making packaging films suitable for packaging foodstuffs, and the like.

Abstract: A process for coating a packaging film with a transparent barrier coating. The process starts with a metal substrate made of, or having a surface coating of, a valve metal or valve metal alloy. The metal substrate is anodized to form an anodic film of the valve metal on the metal substrate. The anodic film is made readily detachable from the metal by carrying out the anodization step in the presence of an adhesion-reducing agent, e.g. a fluoride. The packaging film is then attached to the anodic film and the anodic film is detached from the metal. The transferred anodic film forms a thin dense oxide coating on the packaging film that acts as a barrier against oxygen and moisture transparent. The invention can be used for making packaging films suitable for packaging foodstuffs, and the like.

Abstract: A process for coating a polymer sheet with a transparent coating having moisture and oxygen barrier properties. The process starts with a metal substrate made of, or having a surface coating of, a valve metal or valve metal alloy. The metal substrate is anodized to form an anodic film of the valve metal on the metal substrate. The anodic film is made readily detachable from the metal by carrying out the anodization step in the presence of an adhesion-reducing agent, e.g. a fluoride. The polymer sheet, usually in the form of a thin transparent layer, is then attached to the anodic film and the anodic film is detached from the metal. The transferred anodic film forms a thin dense oxide coating on the polymer sheet that acts as a barrier against oxygen and moisture transport. The invention can be used for making packaging sheets suitable for packaging foodstuffs, and the like.

Abstract: The method involves forming a laminate capable of generating a substantially non-dichroic color by a light interference and absorption phenomenon by depositing a layer of a metal of medium light reflectivity by a vapor deposition technique on a suitable substrate, anodizing a surface of the metal in the presence of fluorine ions to form a detachable film of an oxide of the metal on the surface having a thickness suitable for color generation, and adhering a flexible strip of transparent or translucent material over the oxide film in such a manner that the strength of attachment of the flexible strip to the oxide film exceeds the adhesive strength between the oxide film and said surface of said metal.

Abstract: A laminated color change device which exhibits an irreversible color change upon delamination. The device comprises two layers capable of generating a color by a light interference and absorption phenomenon that requires direct and intimate contact between the two layers. One of the layers is a color-generating metal, such as a valve metal (e.g. tantalum), and the other is an overlying light-transmitting film thin enough to cause light interference effects. The film is produced by coating the color generating metal with aluminum or an aluminum alloy and then anodizing (preferably porous anodizing) the aluminum to consumption in the presence of an adhesion-reducing agent, e.g. fluoride, that reduces the strength of attachment between the layers so that the laminate can be uniformly and reliably separated at the interface between the adjacent two layers. An overlying layer of transparent or translucent material is normally adhered to the laminate to facilitate the separation of the layers.

Abstract: The invention relates to a laminated tamper-evident structure which exhibits an irreversible color change upon delamination. The structure includes a laminate of at least two layers capable of generating a color by a light interference and absorption phenomenon that requires direct and intimate contact between an adjacent two of the layers. The strength of attachment among the layers of the laminate is such that the laminate can be uniformly and reliably peeled apart at the interface between the adjacent two layers. An overlying flexible strip of transparent or translucent material is adhered to the laminate to facilitate the peeling operation. Upon peeling apart the laminate, the generated color is irreversibly lost, thus providing evidence that the structure has been tampered with. The structure can be incorporated into a variety of closable articles or products to provide evidence of opening or tampering.