Abstract: A current limiting device comprises at least two electrodes; an electrically conductive composite material between the electrodes; interfaces between the electrodes the said composite material; and an inhomogeneous resistance distribution structure at the interfaces. During a high current event, adiabatic resistive heating at the interfaces causes rapid thermal expansion and vaporization and at least a partial physical separation at the interfaces; so the resistance of the current limiting device increases. The composite material comprises at least one polymeric matrix material and at least one electrically conductive material, and the polymeric matrix material comprises at least one epoxy and at least one silicone.

Abstract: A current limiting device comprises at least two electrodes; an electrically conductive composite material between the electrodes; interfaces between the electrodes the said composite material; and an inhomogeneous resistance distribution structure at the interfaces. During a high current event, adiabatic resistive heating at the interfaces causes rapid thermal expansion and vaporization and at least a partial physical separation at the interfaces; so the resistance of the current limiting device increases. The composite material comprises at least one polymeric matrix material and at least one electrically conductive material, and the polymeric matrix material comprises at least one epoxy and at least one silicone.

Abstract: A current limiting device comprises at least two electrodes; an electrically conductive composite material between the electrodes; interfaces between the electrodes the said composite material; and an inhomogeneous resistance distribution structure at the interfaces. During a high current event, adiabatic resistive heating at the interfaces causes rapid thermal expansion and vaporization and at least a partial physical separation at the interfaces; so the resistance of the current limiting device increases. The composite material comprises at least one polymeric matrix material and at least one electrically conductive material, and the polymeric matrix material comprises at least one epoxy and at least one silicone.

Abstract: An exemplary current limiting device comprises first and second electrodes; a composite material between the first and second electrodes, the composite material comprising: (a) a binder, and (b) an electrically conductive filler; a thin layer which provides an inhomogeneous distribution of resistance to the device; a web which reinforces the composite material; and a pressurizer for pressing the electrodes against the composite material; wherein the web is disposed in a volume of the composite material which does not include the thin layer. The current limiting device is simple and reusable, and can be tailored to a plurality of applications, including high voltage/current distribution systems, to protect sensitive components from high fault currents. The device has a robust structure which allows it to repeatedly withstand the high mechanical and thermal stresses which typically accompany switching events in high voltage/current circuits.

Abstract: A current limiting device comprises at least two electrodes; an electrically conductive composite material between the electrodes; interfaces between the electrodes the said composite material; and an inhomogeneous resistance distribution structure at the interfaces. During a high current event, adiabatic resistive heating at the interfaces causes rapid thermal expansion and vaporization and at least a partial physical separation at the interfaces; so the resistance of the current limiting device increases. The composite material comprises at least one polymeric matrix material and at least one electrically conductive material, and the polymeric matrix material comprises at least one epoxy and at least one silicone.

Abstract: A hermetically packaged radiation imager includes a moisture barrier cover disposed over the imaging array and a hermetic seal structure disposed around the periphery of the moisture barrier cover to seal the cover to the underlying substrate. The hermetic seal structure comprises a solder seal disposed in contact with the moisture barrier cover and a dielectric material layer disposed between the solder seal and conductive lines extending from the imager array across the substrate surface. The hermetic seal structure further includes a primer layer that is disposed between the dielectric material layer and the solder seal to provide a foundation to which the solder seal adheres. The dielectric material layer is deposited in an atomic layer epitaxy technique, thus providing a thin layer having high structural integrity.

Abstract: A hermetically packaged radiation imager includes a moisture barrier cover disposed over the imaging array and a hermetic seal structure disposed around the periphery of the moisture barder cover to seal the cover to the underlying substrate. The hermetic seal structure comprises a solder seal disposed in contact with the moisture barrier cover and a dielectric material layer disposed between the solder seal and conductive lines extending from the imager army across the substrate surface. The hermetic seal structure further includes a primer layer that is disposed between the dielectric material layer and the solder seal to provide a foundation to which the solder seal adheres. The dielectric material layer is deposited in an atomic layer epitaxy technique, thus providing a thin layer having high structural integrity.

Abstract: A solid state radiation imager includes a photosensor array having a plurality of pixels disposed on a substrate, each pixel having a respective photosensor coupled to a thin film transistor (TFT). The photosensor array further includes an opaque passivation layer that is disposed over non-photodiode areas of the photosensor array, including the TFT and address lines in the array. The opaque passivation layer has an absorbance that is greater than 1, and typically that is greater than 2. The opaque passivation layer further is typically made of a thermally stable polymer mixed with a light absorbing material such as an organic dye (e.g., Sudan Black B), carbon black, or graphite.

Abstract: A method for photolithographically forming a mask includes the steps of: forming an island structure of opaque material on a principal surface of a transparent substrate; depositing at least one layer of transparent material on the principal substrate surface and over the island structure; depositing a layer of photoresist material over the at least one transparent layer; exposing a back-side substrate surface, opposite to the principal substrate surface, to UV light to cause exposure of at least a portion of the photoresist, corresponding substantially to an area outside of a shadow of the island structure; reflecting at least a portion of UV light back into the photoresist layer, by depositing a non-specular layer over the photoresist layer before UV exposure, to expose another portion of the photoresist layer a selected overlap distance within the island structure shadow; and removing the exposed photoresist portion to form a mask which is aligned with the island structure and narrower than the island stru

Abstract: A polyhydrazine is used to insolubilize a soluble polyimide. Soluble polyimide films on printed circuit boards can be insolubilized in this manner.

Abstract: A multi-color liquid crystal display has a one-dimensional or two-dimensional array of at least one display cell, with a plurality of different liquid crystal host/guest dichroic dye compositions in each cell. Each of the different liquid crystal compositions may be provided within separate microcapsules, with the totality of micro-capsules being blended to provide the total composition filling the cell volume or dielectric spacers may be utilized to divide the volume of each display cell into a like plurality of subvolumes, each containing a different liquid crystal material. Liquid crystal hosts of substantially-constant or variable dielectric anisotropy magnitude and polarity are selected to cause different ones of the plurality of compositions within a cell to switch between transmission and absorption of various visible-wavelengths regions as the frequency and amplitude of an electric field within the cell is varied by control electronics of a display system.

Abstract: Novel asymmetric tris-azo dye compositions and a liquid crystal composition containing the asymmetric tris-azo dye compositions are disclosed. The asymmetric dye compositions having asymmetric terminal groups have the general formula: ##STR1## wherein R.sub.1 is one of the three following groups: ##STR2## 5-nitrothiazolyl group, 4-cyanophenyl group, and 4-nitrophenyl; wherein R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are selected from the group consisting of hydrogen, alkyl, halogen and alkoxy, and R.sub.6 is selected from the group consisting of N,N-diethylamino-3-methylphenyl; N,N-diethylamino-3-methylphenyl; N,N-diethylamino-3,5-dimethylphenyl; 2-pentylperimidyl; N-ethylamino-1-naphthyl; N,N-dimethylamino-1-naphthyl; and N,N-diethylamino-1-naphthyl. When the asymmetric tris-azo dichroic dyes are used as a guest in a host liquid crystal material, they form a novel liquid crystal composition for use in liquid crystal displays.

Abstract: Liquid crystal compositions having guest perylene-based dichroic dyes dissolved therein. The perylene dichroic dyes have symmetrically-disposed substituents which are preferably a group forming with the 3,4 and 9, 10 carbons, respectively, a 5 or 6 membered cyclic ring which is substituted by, or fused to, a phenyl ring. The perylene-based dyes of the invention can be used alone or with other compatible dyes as guest dyes to form various colors for coloring the host liquid crystal compositions.

Abstract: Novel tris-azo dyes and a liquid crystal composition containing the tris-azo dyes. The tris-azo dyes are of the general formula: ##STR1## wherein R.sub.1 and R.sub.2 are various aromatic groups including aromatic amines, substituted aromatic amines, hydroxy-substituted aromatic groups and substituted hydroxy-containing aromatic groups. When the tris-azo dichroic dyes are used as a guest dye in a host liquid crystal material, they form a novel liquid crystal composition for use in liquid crystal displays.

Abstract: Novel tris-azo dye compositions and a liquid crystal composition containing the tris-azo dye compositions are disclosed. The tris-azo dye composition having terminal aromatic groups has the general formula: ##STR1## wherein R.sub.1 and R.sub.2 are various aromatic compounds including aromatic amines, substituted aromatic amines, hydroxy-substituted aromatic compounds and substituted hydroxy-containing aromatic compounds. When the tris-azo dichroic dyes are used as a guest dye in a host liquid crystal material, they form a novel liquid crystal composition for use in liquid crystal displays. Examples of R.sub.1 and R.sub.2 include organic radicals of aminoquinoline, tetrahydroquinoline, N-ethyl-1-naphthylamine and 1,8-diaminonaphthalene.

Abstract: Cells, such as liquid crystal display cells, having a material contained between a pair of parallel, spaced-apart substrates, are sealed to prevent permeation therein of vapor which is potentially harmful to the material contained within the cell, by reducing the area of relatively high permeation material at the cell boundary and/or by completely enclosing the boundary in a permeation resistant barrier of inorganic material.

Abstract: Novel yellow azo dye compositions and a liquid crystal composition containing the yellow azo dye composition are disclosed. The yellow azo dye composition, having terminal ester groups has the general formula: ##STR1## wherein R and R' are acyl groups having the formula: ##STR2## and R.sub.2 is an alkyl or substituted alkyl wherein the alkyl has at least 4 carbon atoms, or R.sub.2 is an aryl, arylalkyl, substituted aryl or substituted arylalkyl. When the yellow azo dichroic dyes are used as a guest in a host liquid crystal material, they form a novel liquid crystal composition for use in liquid crystal displays. The disclosure also embraces a method of improving the black color of dichroic dyes for use in black liquid crystal displays, wherein a dye composition having a mixture of dichroic dyes of various colors and containing at least one yellow azo dichroic dyes as described above is added to a host liquid crystal material.

Abstract: Novel yellow azo dye compositions and a liquid crystal composition containing the yellow azo dye composition are disclosed. The yellow azo dye composition, having terminal ester groups, has the general formula: ##STR1## wherein R and R' are acyl groups having the formula: ##STR2## and R.sub.2 is an alkyl or substituted alkyl wherein the alkyl has at least 4 carbon atoms, or R.sub.2 is an aryl, arylalkyl, substituted aryl or substituted arylalkyl. When the yellow azo dichroic dyes are used alone, or in combination with other dyes, as a guest in a host liquid crystal material, they form a novel liquid crystal composition for use in liquid crystal displays. The disclosure also embraces a method of improving the black color of dichroic dyes for use in black liquid crystal displays, wherein a dye composition having a mixture of dichroic dyes of various colors and containing at least one yellow azo dichroic dye, as described above, is added to a host liquid crystal material.

Abstract: Novel yellow azo dye compositions and novel liquid crystal compositions containing the yellow azo dye composition. The yellow azo dye composition, having terminal ester groups, has the general formula: ##STR1## wherein R and R' are alkyl or substituted alkyl wherein the alkyl has at least 4 carbon atoms, aryl, arylalkyl, substituted aryl or substituted arylalkyl. When the yellow azo dichroic dyes are used alone, or in combination with other dyes, as a guest in a host liquid crystal material, they form a novel liquid crystal composition for use in liquid crystal displays. An invention method of improving the black color of dichroic dyes for use in black liquid crystal displays, wherein a dye composition having a mixture of dichroic dyes of various colors and containing at least one yellow azo dichroic dye, as described above, is added to a host liquid crystal material.

Abstract: Novel yellow azo dye compositions and a liquid crystal composition containing the yellow azo dye composition are disclosed. The yellow azo dye composition, having terminal ester groups has the general formula: ##STR1## wherein R and R' are acyl groups having the formula: ##STR2## and R.sub.2 is an alkyl or substituted alkyl wherein the alkyl has at least 4 carbon atoms, or R.sub.2 is an aryl, arylalkyl, substituted aryl or substituted arylalkyl. When the yellow azo dichroic dyes are used as a guest in a host liquid crystal material, they form a novel liquid crystal composition for use in liquid crystal displays. The disclosure also embraces a method of improving the black color of dichroic dyes for use in black liquid crystal displays, wherein a dye composition having a mixture of dichroic dyes of various colors and containing at least one yellow azo dichroic dye as described above is added to a host liquid crystal material.