Raychem Limited

Other

Tyco Electronics Corporation

Mark S Thompson

Michael T Zhang

Gary H Wiseman

Paul Becker

Daniel A Chandler

Shou-Mean Fang

Chi-Ming Chan

Dennis C Siden

Ryan W Dupon

Douglas J Musolf

James J Toth

Lawrence J White

William C Beadling

Adam C Tanous

Edward S Sherman

Gregory A Graves

Philip J Jones

A Brian Macknick

Andrew Tomlinson

Justin N Chiang

Carol Powers

Adam S Tanous

Dennis E Glover

Michael Mengruo Zhang

An electrical device which comprises first and second laminar electrodes and a laminar PTC resistive element sandwiched between them, the device comprising

Electrical devices

Electrical devices, particularly circuit protection devices, contain conductive polymer elements whose edges are formed by breaking the conductive polymer element, along a desired path, without the introduction of any solid body into the element. The resulting cohesive failure of the conductive polymer produces a distinctive fractured surface. One method of preparing such devices involves etching fracture channels in the electrodes of a plaque containing a PTC conductive polymer element sandwiched between metal foil electrodes, and then snapping the plaque along the fracture channels to form individual devices.

Electrical device

Electrical devices containing a conductive polymer element having a

A circuit protection device which comprises first and second laminar electrodes; a laminar PTC conductive polymer resistive element sandwiched between the electrodes; a third laminar conductive member which is secured to the same face of the PTC element as the second electrode but is separated therefrom; and an electrical connector which connects the third conductive member and the first electrode. This permits connection to both electrodes from the same side of the device, so that the device can be connected flat on a printed circuit board, with the first electrode on top, without any need for leads. The connector is preferably a cross-conductor which passes through an aperture in the PTC element, because this makes it possible to carry out the steps for preparing the devices on an assembly which corresponds to a number of individual devices, with division of the assembly as the final step.

The invention takes the form of a hydrodynamic plane which carries a fishing line up and down along a weighted downrigger trolling line. The position of the plane is controlled by the fisherman through the fishing line which is releasably clipped to a leader attached to the trailing edge of the plane. Whenever there is a mild amount of tension on the fishing line the plane is held in a down-planing position so that the device will dive and be held against the downrigger weight by the hydrodynamic force. The weight of the plane is balanced so that when the tension on the fishing line is relieved or if the fishing line is released from the friction clip, the plane will automatically pivot to an up-planing position and rise to the surface. Thus, the plane will automatically rise to the surface when a fish strikes the hook, or the fisherman can make the device rise to the surface on command without releasing the fishing line so that he or she can check the bait or the lure and send the device back down again.

Hydrodynamic plane for downrigger fishing

A metal oxide dielectric dense body, comprising (I) grains having a predominant crystalline phase (a) a primary metal oxide selected from the group consisting of silicon and magnesium oxide and (b) optionally a secondary metal oxide selected from the group consisting of aluminum and zinc oxide and (II) between about 1 and about 20 atom % bismuth, vanadium, or boron oxide or combination thereof, discontinuously located at the boundaries of the crystalline grains or as inclusions in the crystalline grains, the atom %'s based on the total atoms of bismuth, vanadium, boron, silicon, magnesium, aluminum, and zinc. The dense body has a density which is at least 95% of theoretical.

Metal oxide dielectric dense bodies, precursor powders therefor, and

An article having an array of varistors, including (a) a varistor body made of varistor material and having two major opposing faces, one of the opposing faces having an array of indentations thereon; (b) conductor material on the opposing face having the indentations, the conductor material filling the indentations and forming multiple leads for connection to electrical circuitry; and (c) conductor material on the other opposing face, forming multiple leads for connection to electrical circuitry.

Low voltage varistor array

A metal oxide dielectric dense body, comprising (I) grains having a predominant crystalline phase (a) a primary metal oxide selected from the group consisting of silicon and magnesium oxide and (b) optionally a secondary metal oxide selected from the group consisting of aluminum and zinc oxide and (II) between about 1 and about 20 atom % bismuth, vanadium, or boron oxide or combinations thereof, discontinuously located at the boundaries of the crystalline grains or as inclusions in the crystalline grains, the atom %'s based on the total atoms of bismuth, vanadium, boron, silicon, magnesium, aluminum, and zinc. The dense body has a density which is at least 95% of theoretical.

A liquid crystal display comprises (a) a first transparent base; (b) a plurality of first picture electrodes on the first transparent base; (c) a plurality of data lines for supplying electrical signals to the first picture electrodes; (d) a second transparent base, parallel to and spaced apart from the first transparent base; (e) a plurality of second picture electrodes on the second transparent base; (f) a plurality of varistor elements made of a varistor material comprising zinc oxide as a primary metal oxide and cobalt and praseodymium oxides as additive metal oxides, in amounts of between 0.1 and 8.0 atom % cobalt and between 0.08 and 8.0 atom % praseodymium, one varistor element being associated with and in electrical contact each second picture electrode; (g) a plurality of scan lines for supplying electrical signals to the second picture electrodes via the respective associated varistor elements; and (h) electrooptically active liquid crystal material between the first and second picture electrodes. In a preferred embodiment, the plurality of varistor elements is in the form of a varistor array comprising an integral body of varistor material having two major opposing faces, one of the opposing faces having an array of indentations thereon, each indentation defining a varistor element.

Varistor driven liquid crystal display

This invention provides a process for making metal oxide varistor precursor powder comprising (a) dissolving soluble precursors of the additive metal oxides, e.g. bismuth nitrate as precursor for bismuth oxide, in an aqueous solution, (b) forming a suspension or slurry in the aqueous solution of a powder of the desired primary metal oxide, e.g. zinc oxide, having the desired particle size, (c) adding a precipitating reagent to convert the additive metal from the soluble precursor form to the oxide or hydrous oxide form and precipitate the oxide or hydrous oxide in the presence of the primary metal oxide particles, (d) removing water and by-product salts to form a powder. The resulting varistor precursor powder contains smaller particles of the additive metal oxides evenly distributed throughout larger particles of the primary metal oxide. Varistors prepared from the resulting powder can be sintered at temperatures lower than conventionlly used, for example 900.degree. C.-1000.degree. C. and the resulting varistors exhibit properties of volts per grain boundary value higher than conventional varistors for example 3.75 to 4.5 and dielectric constants lower than conventional varistors, e.g., under 1000.

Metal oxide varistors, precursor powder compositions and methods for

A varistor comprises a primary varistor metal oxide, aluminum in an amount of about 1 to about 30 parts per million (ppm), about 0.1 to about 0.5 mole % bismuth, about 0.1 to about 1.5 mole % antimony, about 0.1 to about 1 mole % chromium, about 0.1 to about 1.0 mole % manganese, about 0.1 to about 2.0 mole % cobalt, and about 0 to about 1.0 mole % boron. Each of these elements is present in the form of its oxide and the varistor has a DC leakage current at 80% of V.sub.1ma/cm.spsb.2 of less than 1.0.times.10.sup.-7 amp/cm.sup.2.

Metal oxide varistors and methods therefor

Device and method for detecting the presence of gas in refrigeration systems and other evacuated systems. The exhaust from a vacuum pump connected to the system is passed through a gas detector having a reservoir of liquid in which bubbling can be observed. The exhaust is normally discharged through a discharge opening in the detector. The opening is blocked with the hand to divert the exhaust from the vacuum pump into the liquid to produce bubbling in the liquid in the event that any gas is present in the exhaust.

Gas detector and method for refrigeration systems

A conductive polymer composition which exhibits PTC behavior comprises a crystalline organic polymer, carbon black, and a high resistivity particulate filler. The high resistivity filler is semiconductive and has a resistivity at least 100 times that of the carbon black. Compositions of the invention exhibit good resistance stability when exposed to thermal cycling. They are useful in electrical devices requiring compositions with high resistivity.

Growing community of inventors

San Carlos, CA, United States of America

Mark S Thompson