Abstract:
A multi layer interference coating comprising at least one multi layer stack deposited on a reflective layer (9), wherein each multi layer stack comprises a first dielectric layer (11), a layer of absorbing material (10) and a second layer of dielectric material (11) arranged in series and having a reflectance spectrum in the infrared region comprising at least one maximum. The dielectric layers are of equal optical thickness and typically are of the same material. The multi layer structure of the coating is such that incident electromagnetic radiation, for which odd multiples of half wavelengths correspond to the optical thickness of the multi layer coating at the incident wavelength do not propagate within the coating and reflection at these wavelengths, is suppressed. Coatings may therefore be designed to have a near satured colour in the visible wavelength spectrum. The reflective layer may be a metal or a conducting oxide, a conducting nitride, a conducting silicide or a conducting sulphide. The absorbing layers may be Cr, V, Pd, Ni, Pt, conducting oxides, or substoichiometric metal oxides, such as TiOx. In one form of the coating, where a non-metal absorber is used, the second dielectric layer may be removed in at least one of the multi layer stacks. The coating may be incorporated in a system for verifying the authenticity of an article.
Abstract:
The present invention provides a two-component infrared reflecting film which reflects light in the infrared region of the spectrum while suppressing second, third and fourth order reflections in the visible spectrum. The film comprises alternating layers of first (A) and second (B) diverse polymeric materials having a six layer alternating repeat unit with relative optical thicknesses of .778A.111B.111A.778B.111A.111B. The polymeric materials differ from each other in refractive index by at least 0.03.
Abstract:
A colour cast compensating filter for optical appliances has an interference filter layer with the following composition (for a reference wavelength (lambda) = 500 nm): nG (glass dispersion disk) / 0.3019 H / 0.6179 L / 0.7495 H / (0.4910 L / 0.9722 H)5 0.9616 L / 2.0773 H / 0.4700 L / 0.6630 H / 1 (air). The low refraction material consists of MgF2 whereas the high refraction material consists of a substance constituted by the group ZrO2, Ta2O5, HfO2, a mixture of metal oxides and rare earth oxides. This interference filter layer allows the light intensity of a complex optical appliance with viewing and photographic beam paths for different wavelengths to be influenced in a defined manner, so that a colour-neutral photographic reproduction and viewing of the microscoped objects may be obtained. This interference filter layer is produced by high-vacuum vapour deposition. The glass substrate may have an index of refraction nG between 1.52 and 1.9. The angle of incidence is equal to (0 +- 10) .
Abstract:
A protective arrangement against the damaging effect of radiation which also indicates exposure to radiation is preferably designed as a viewing window or spectacles for protecting the eyes against damages caused by high intensity electromagnetic radiation. The arrangement consists of a transparent substrate and of a series of thin optical layers applied thereon arranged according to the principle of an optical thin layer resonance absorber system.
Abstract:
An optical filter (120) used in applications involving spectroscopic measurements is fabricated by depositing layers (111) of optical coatings onto a substrate (110). The layers (111) are deposited so as to have a substantially constant thickness in a first direction along the surface of the substrate (110), and a gradually increasing thickness along a direction perpendicular to the first direction. The structure of the optical filter (120) allows for large scale production of the filter so that costs in producing the filter are greatly reduced. The filter (120) may be used in a variety of applications including, but not limited to chemical analysis, blood glucose monitoring, and the like.
Abstract:
The durability of thin metal coatings and particularly substantially transparent copper and silver plus noble metal coatings and their ability to withstand corrosive environments is improved by overcoating the metal layers (14) with a double coating of dielectric. The first coating (16) is made up of dielectric based on indium and/or zinc. The second coating (18) is made up of dielectric based on indium and tin. These overcoatings are more effective than a single coating based on one metal or a single coating based upon the two metals.
Abstract:
A method of manufacturing optical filters comprises the steps of depositing a plurality of monomolecular layers of at least one organic material on a substrate using Langmuir Blodgett techniques. The optical characteristics of the organic material or materials is known and, using the aforesaid technique, layers of predetermined optical thickness can be deposited. The organic material or one of the organic materials has non-linear optical characteristics so that a variable filter is formed.
Abstract:
The system has two identical filtering devices (1, 2), each of them comprising reflecting elements (3, 4 and 5, 6) and radiation-passing elments (7, 8). The wavelength of the maximum bandpass of one filtering element (1) differs from the wavelength of the maximum bandpass of the other filtering element (2) by a value sufficient for diminishing the pass coefficient of the first device (1) down to a value equal to or exceeding 0.85 of its maximum. The contours of the bandpasses of the devices (1, 2) being mutually offset, the lateral maxima of the bandpass contours of one filtering device (1) will not pass through the second device (2).
Abstract:
An interference filter (10, 30, 50, 70, 90, 110, 130, 150, or 190) filters selected wavelengths by dividing an input beam into two or more intermediate beams having different optical path lengths and by recombining the intermediate beams into an output beam that is modified by interference between the intermediate beams. An optical path length difference generator (20, 40, 60, 80, 100, 120, 140, 160, or 200) varies the optical path lengths of the intermediate beams by changing the physical lengths of their paths or the refractive indices of the mediums in which they are conveyed. The optical path length generator (20) of one exemplary embodiment (10) includes a spacer plate (20) that is divided into solid optical elements (22 and 24) having different refractive indices for varying the optical path lengths of the intermediate beams. Another optical path length difference generator (140) is formed by a stack of partially reflective surfaces (144) that are spaced apart in the direction of beam propagation by at least one nominal wavelength for varying the physical path lengths between the intermediate beams.
Abstract:
A transparent multilayer device, which reflects light in the infrared region of the spectrum while transmitting light in the visible region of the spectrum, comprising a multilayered polymer film and a transparent conductor. The multilayered polymer film preferably comprises layers of a semi-crystalline naphthalene dicarboxylic acid polyester having an average thickness of not more than 0.5 microns and layers of a second polymer having an average thickness of not more than 0.5 microns. The layers of semi-crystalline naphthalene dicarboxylic acid polyester preferably have a positive stress optical coefficient. The transparent conductor comprises at least one layer containing a metal or a metal compound in which the metal compound is preferably selected from the group consisting of metal oxides, metal alloys, and combinations thereof. Silver and indium tin oxide are particularly preferred transparent conductors. The transparent multilayer devices may be applied to the surface of a glass or plastic substrate, such as an exterior window in a building, or to a windshield or window in an automobile, truck, or aircraft.