National Research Council of Canada

Other

Li Li

Jerzy A Dobrowolski

Brian T Sullivan

Peter D Grant

Tu Dien Do

Daniel Poitras

Zhengda Pang

Frank Xu

Samuel Chen

Yi Oin

Zoran Milojevic

Jianping Jiang

Anna Cheung

Jianli Wang

Andre Moskal

Edward Ndububa

Chunsheng Xie

J A Dobrowolski

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 signalling switch for use in information protocol telephony is provided, which can initiate, sustain, and terminate a plurality of discrete voice and data calls simultaneously. A plurality of cards are mounted on a computer bus, where the first card is a single board computer whose function is to act as the operations and maintenance control card for the switch. A non-system card functions as a message transport controller card; and there is at least one further non-system card which functions as a master application controller card. Local bus communication among the non-system cards is provided by a local bus found on the message transport controller card. Telephone routing information protocol software is resident in the switch, and the switch communicates externally via Ethernet interfaces. Thus, the signalling switch may be positioned in an information protocol telephony network environment to initiate, sustain, and terminate connections between a client and the network or the network and a client, under the control of the resident telephone routing information protocol software.

Signaling switch for use in information protocol telephony

An optical device for controlling the flow of light between ports includes a pair of polarizing devices, which employ frustrated total internal reflection and interference in a thin film coating to reflect p-polarized light and to transmit s-polarized light. Polarization-rotating devices are used to rotate the polarization plane of the s- and p-polarized light beams so as to create optical switches, isolators and circulators using these polarizing devices.

High isolation optical switch, isolator or circulator having thin film polarizing beam-splitters

A polarizing light source for providing polarized illumination over a two-dimensional surface has a slab-like light guide with an entrance face at one end thereof for admitting unpolarized light from a linear source, a planar front face for emitting polarized light, a planar back face, and an end face. A polarizing device is located on said back face for reflecting light of a first polarization and transmitting light of a second polarization at non-normal angles of incidence. The reflected light is directed in the light guide to the end face. A reflective arrangement under the polarizing device returns the transmitted light to the light guide in a direction substantially normal to the polarizing device such that it passes unaffected through the polarizing device for exit through the front face. A polarization converter on the end face changes the polarization of the reflected light and directs it into the reflective arrangement through the polarizing device as light of the second polarization for return to the light guide through the polarizing device in a direction substantially normal to the polarizing device such that it passes unaffected through the polarizing device from the reflective arrangement for exit through said front face.

Polarizing back-lighting system for direct view liquid crystal displays

A cut-off filter is based on the use of light at non-normal angles of incidence and on the use of coating materials with a large dispersion of the optical constants. The filter has a pair of optical media respectively defining an inlet port and an outlet port and having an inclined interface such that a light beam passing between the inlet and outlet ports strikes the interface at a non-normal angle of incidence. An active core is sandwiched between the optical media at the interface. In one embodiment, the active core has a refractive index which has high dispersion in the vicinity of the predetermined cut-off wavelength and an extinction coefficient which is high on the cut-off side and low on the transmission side. The angle of incidence &agr; is selected such that total internal reflection occurs at the predetermined wavelength &lgr; to bring about a sharp cut-off in the transmittance of the filter at the predetermined wavelength.

Cut-off filters

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

The prevention of counterfeiting of currencies, passports, cheques, bank cards, credit cards, optical disks and the like is addressed by introducing thin film structures having both optically-variable security properties and encoded optical data decodable by optical means. The thin film structures comprise a substrate and a multilayer interference coating carried by the substrate, producing an inherent color shift with a change of viewing angle. The multilayer interference coating has a dielectric material which is transparent and the recording layer made of a light absorbing material, a crystalline-structural changing material or a magneto-optic material. The encoded data is in the form of bar codes or digital data. The information is encoded by photolithographic means or by optical recording means. The encoded data is retrieved by an optical recording system having a light source and an optical guiding system and a light detector.

Optical recording media having optically-variable security properties

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.

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Ottawa, Canada

Li Li