National Research Council of Canada

Canadian Patents & Development Ltd.

Other

Canadian Patents and Development Limited/societe Canadienne Des Brevets

Jerzy A Dobrowolski

Li Li

Brian T Sullivan

Peter D Grant

Allan J Waldorf

Lorne Arthur Whitehead

Takashi Ito

Elmer H Hara

Michael Davies

Simon Andrew Boothroyd

Daniel Poitras

Glenn A Clarke

Robert C Bajcar

Fang C Ho

Roger A Kemp

Takayuki Akiyama

A polarizing beam splitter has a pair of opposed transparent prism substrates with a refractive index n, and providing at least one input port and at least one output port. The input port accepts light incident over a range of operational angles including a central operational angle. A multilayer thin film structure is sandwiched between the pair of opposed transparent substrates and consists essentially of a plurality of layers l. . . lhaving respective refractive indices n. . . n, wherein at least three of said refractive indices n. . . nare different, and wherein the refractive index of the substrates nlies between the highest refractive index nand lowest refractive index n, and wherein n, nand ndefine a Brewster angle &#x3b8;: a critical angle &#x3b8;: The refractive indices nand n. . . nare selected such that the central operational angle for a beam incident on the multiple thin film structure lies above the Brewster angle &#x3b8;and such that most or all the operational angles defined by said input port lie above the Brewster angle &#x3b8;. For p-polarized light at least one optical admittance of the layers with refractive indices n. . . nis lower or very close to that of the optical admittance of the substrate for the operational angles such that the thin film polarizing beam-splitter favors the transmittance for p-polarized light incident at that input port such that most of the p-polarized light is transmitted through the multiple thin film structure. For s-polarized light the polarizing beam-splitter acts as a high reflective coating to favor the reflectance for s-polarized light incident at the input port such that most of the s-polarized light is reflected from said multiple thin film structure. The polarizing beam splitter is compact and yet remains functional over a wide range of operational angles.

Polarizing beam splitters

An organic light emitting device consists of a layered structure including a top multilayer stack, a bottom multilayer stack, a cavity layer between the top multilayer stack and the bottom multilayer stack, and an organic light emitting region within the cavity layer. The layered structure is constructed such that the product of phase factors &#x3be;and &#x3be;is. greater than 80% at the center of at least one emitting wavelength region and for a normal viewing angle, wherein where Rand Rare the reflectance of the top and bottom multilayer stacks respectively, &#x3c6;and &#x3c6;are the phase changes on reflection for the top and bottom multilayer stacks respectively, &#x3b1;&#x3b2;are respectively the real and imaginary parts of the phase thickness of the cavity layer, &#x3b1;and &#x3b2;are respectively the real and imaginary parts of the phase thickness of the light-emitting region at the operating wavelength of the device, x is the mean distance of light emitting region from the bottom multilayer stack, n and k are the refractive index and absorption coefficient of the cavity layer, &#x3b8;is the emitting angle inside the cavity layer, and d is the physical thickness of said cavity layer. This condition improves the light output efficiency of the device.

High performance light-emitting devices

A method is described for depositing a complex optical multilayer coating on a substrate. The coating consists of multiple layers of at least two material types. The layers are sequentially deposited in a deposition chamber by reactive deposition; preferably sputtering, and the thickness of the deposited layers is determined one or more times during the layer deposition by taking optical measurements of the deposited layer and fitting theoretical values derived from a model of the deposited layers to the corresponding actual values obtained from said measurements. A process variable is continually controlled to ensure homogeneity of the deposited layers so that a valid thickness determination can be made from said theoretical model.

Multi-layer reactive sputtering method with reduced stabilization time

High efficiency projection displays having thin film polarizing

A thin film polarizing device has first and second light transmissive substrates in the form of prisms and a plurality of thin film layers disposed between the prisms. The thin film layers and have predetermined thicknesses and refractive indices which allow unpolarized incident light to be separated into s-polarized and p-polarized light beams. Both frustrated total internal reflection and thin film interference are simultaneously employed to allow s-polarized light to be transmitted and p-polarized light to be reflected over a wide range of wavelengths and angles of incidence. The polarizing device may be used as a polarizer or a polarizer beam splitter.

Thin film polarizing device

A semiconductor device comprises a plurality of colored deformable mirrors controllable by electrical circuitry. Groups of mirrors, responsive to the electronic signals, are selectably operable to reflect incident light. The deformable mirrors are coated with an optical thin film interference color coating having at least a layer that is substantially transparent to the visible light. As well the optical thin film interference color coating includes at least one further layer that is partially absorbing with respect to the visible light. The spectral reflectance and absorptance of the deformable mirror is modified in order to obtain a desired reflected color by the process of optical interference enhanced absorption in the optical thin film interference color coating. The optical thin film interference color coating has predetermined layer thicknesses and materials; the substantially transparent layer substantially determines the desired reflected color.

Color deformable mirror device having optical thin film interference

An authenticating system for verifying articles is provided. The articles to be verified have a thin film multilayer coating applied to them that serves or functions as a type of finger print. In a reflective mode of operation the coating is designed to reflect light radiation of predetermined wavelengths and substantially absorbing or transmitting light radiation of other predetermined wavelengths irradiating a same location on the coating surface; in operation a light source is provided for irradiating light onto said location on the coating surface; and a detector is used to determine the presence and absence within predetermined limits of each of said predetermined wavelengths of light at said location that are substantially reflected by the coating. The system may also be configured in a transmissive mode or an absorptive mode of operation when used with the compatible detection schemes as exemplified herein.

Authenticating system

An optical filter is provided for suppressing unwanted reflections of background light when used with a display device such as a cathode ray tube or an electroluminescent screen, or in optical communication or surveillance. The filter has multiple thin layers including a first series of layers for suppressing reflections from its outer surface and a second series of layers constituting a bandpass interference filter. The first series of layers is arranged to suppress reflections over a broad wavelength band while the second series of layers allows transmittance over a relatively narrow wavelength passband within the broad wavelength band, resulting in improved contrast when the display is used in situations of high background light.

Optical filters for suppressing unwanted reflections

An optical recording medium for storing data is provided having a visible logo on a read side of the medium for providing some anticounterfeiting protection. A logo coating for producing the visible logo is carded by the read-side of the substrate; the coating has a sufficiently high transmittance at a read or write wavelength such that light at the read or write wavelength passing through the logo coating toward the other side of the substrate and reflected back through the logo is substantially transmitted and unchanged by the coating so that the data can be detected as well the coating is sufficiently light absorbing in the visible spectrum such that there is a visible contrast between the recording coating and the logo coating. In another embodiment, the logo coating forms a portion of a reflective recording layer on the other non-read side of the substrate. In this case, the logo coating is visually distinguishable from the rest of the recording layer and is made of a different material. For example, the logo may be gold and the rest of the recording layer may be aluminum, or vice versa.

Optical storage media having visible logos

An optical interference electroluminescent device having low reflectance comprises three layers forming an electroluminescent transparent front electrode, a counter electrode and an electroluminescent layer between the electrodes, with or without dielectric layers between them, and at least one optical interference film layer sandwiched between two of the layers or at the faces of the electrodes. The optical interference layer comprises at least one transparent optical interference film and is in interfacial contact with a layer so that the reflectance of ambient light by the device is reduced by optical interference at the interfaces between the layers and the film(s). The optical interference layer(s) may include at least one partially absorbing film. The device may have arrays of electrodes forming pixels.

Optical interference, electroluminescent device having low reflectance

A hard to simulate, readily distinguishable from counterfeits, optical interference authenticating device comprises a substrate, and two optical interference coatings in interfacial contact on one side of the substrate, one of the optical interference coatings being a contrast coating, the other of the optical interference coatings being a form depicting coating for depicting a form relative to the contrast coating. The optical interference coatings each comprising at least one optical interference layer the material and thickness of which has been selected for the coatings to have different, particular, known spectral reflectance and spectral transmittance characteristics from one another when viewed at a particular angle, such that the form depicting coating is visible by reflected or transmitted light of particular coloration, when viewed at the particular angle, at least in part by optical interference of light partically reflected or transmitted at the interfacial contact. A further optical interference contrast coating may be provided on the substrate and the form depicting coating may be sandwiched between the contrast coatings. The substrate may be transparent, semi-transparent or opaque, depending how the spectral characteristics are to be observed. A marginal edge portion of the form depicting coating may taper in thickness to provide a multicolored auriole around the form. A plurality form depicting coatings may be provided which overlie one another to provide a more complex pattern.

Form depicting, optical interference authenticating device

An optical mixing/demixing device is provided comprising a series of solid, light transmitting blocks, each having opposed, front and rear parallel, planar faces, coated with optical interference multilayer coatings, and first and second light transmitting faces arranged one on each side of the front planar face. The blocks are packed side by side with a precision, light expanding and collimating lens on the first light transmitting face and further, similar precision lenses on each of the second light transmitting faces. The first and second light transmitting faces may also be coated with optical interference multilayer coatings that are pass band filters.

Optical mixing/demixing device

A viewing angle color sensitive lighting accessory comprising a sheet member capable of transmitting light, emitting from a visible light source, forwardly towards an area from which light is to be perceived, at least one optical interference multilayer coating on the sheet member and a reflector secured to the sheet member and extending around the light source. The coating has a transmittance which is a function of wavelength and angle of incidence, and in most instances, of state of polarization of the visible light thereto so that the light perceived from the light source has a particular coloration and, if desired, polarization at a particular viewing angle to the coating. The light source may be, for example, an incandescent light source or a light guide, or any other luminaire. The means securing the sheet member to the reflector preferably removably secures the sheet member thereto.

Viewing angle color sensitive lighting accessory

Hard to simulate, readily distinguishable from counterfeits, optical interference authenticating devices are provided by depositing two coatings on a substrate, each coating comprising at least one optical interference layer, the material of each layer being selected so that the two coatings together and separately have different spectral reflectance and spectral transmittance characteristics at different angles of incidence of light thereon. The substrate may be, for example, a polyester film and a first one of the coatings is sufficiently radiation absorbing of, say, infrared radiation that at least one portion of that coating can be removed by an infrared laser beam through, for example, a mask to provide a readily distinguishable pattern on the substrate. The first coating may be, for example, a multilayer absorber coating containing Inconel, aluminum or some other suitable material, while the other coating, which is insufficiently radiation absorbing by, for example, infrared radiation to be substantially resistant to excavation solely by the infrared laser beam may be, for example, a multilayer coating of ZrO.sub.2 or SiO.sub.2, etc. If the first coating is outermost from the substrate then only the first coating will be excavated by the infrared laser beam. If the second coating is outermost from the substrate then both the first and second coatings will be excavated by the infrared laser beam.

Method of manufacturing an optical interference authenticating device

A vapor deposition apparatus for continuously regulating the deposition thickness from vapor as it is being vacuum deposited across and progressively along one side of a substrate from one or more vapor sources spaced thereacross. The apparatus comprises a central shaft rotatably supporting hollow shafts in end-to-end relation, a series of profile discs on each of the hollow shafts and slidable radially thereon by a slot in each profile disc slidably locating on flats on the hollow shafts. The profile discs are placed between vapor sources, and the substrate moving through a vacuum coating chamber so that the profile discs form a mask controlling the vapor deposition across the substrate. The hollow shafts are coupled to electric motors which may rotate the hollow shafts in response to signals from deposition thickness sensing means.

Growing community of inventors

Ottawa, Canada

Jerzy A Dobrowolski