Raychem Limited

Laurence M Welsh

Ray F Stewart

Robert S Wasley

Akira Tomita

Robert H Reamey

John G Lahlouh

Aldrich N Lau

Mark F Wartenberg

John R Havens

Paul S Drzaic

Wayne Montoya

Harriette Atkins

Janusz Wojtowicz

Paul D Hauptly

James Strain

James P Reed

Peter L Brooks

Mauro Bonomi

Larry R Reeder

Michael Masia

Louis M Frank

Thomas W Tolles

Denis I Wales

John Lahlough

A liquid crystal display is made from an encapsulated liquid crystal structure comprising a liquid crystal composition dispersed in a containment medium. Selected additives may be added to the encapsulated liquid crystal structure to improve performance characteristics such as the operating field, the hysteresis, and the voltage holding ratio.

Encapsulated liquid crystal structures, apparatus containing the same,

Detection of liquid leaks and other changes in variables is disclosed. The event causes two elongate conductors to become electrically connected at a location which is determined by the event, thus creating a system in which the connection point can be located by measuring the potential drop from one end of one of the conductors (called the locating member) to the connection point. The system comprises a balancing component so that its sensitivity is not dependent on the location of the event along an elongate path. A fixed current flows through the connection, so that the result is independent of the resistance of the connection. The locating member can be a continuous resistive wire, coated with a conductive polymer; such a locating member can form part of a sensor cable in which the elongate components of the circuit are in a wrapped configuration. Alternatively the locating member comprises a plurality of discrete resistors. The system is arranged so that only connections within a certain range of resistance will activate the system. The voltage drop is calculated by comparing it to the voltage drop over a resistor of known size. Particular event-sensitive connection means are employed for the detection of hydrocarbons.

Method for detecting and obtaining information about changes in variables

Devices for detecting and obtaining information about an event, for example the presence of a liquid, which comprise (1) a swellable member which swells upon occurrence of the event and (2) a restraining member which, when the swellable member swells, restricts movement of the swellable member and thus causes the impedance of the device to change. In a preferred embodiment the device comprises two elongate conductors helically wrapped around a support core, a swellable, conductive polymer member surrounding the conductors. Occurrence of an event causes the swellable material to swell and form a conductive bridge between the conductors.

Sensors for detecting and locating fluids

Detection of events, e.g. liquid leaks and other changes in varibles. The event causes two conductors to become electrically connected, and thus creating a system in which the connection point can be located by measuring the potential drop from one end of one of the conductors (called the locating member) to the connection point. Preferably a fixed current flows through the connection, so that the result is independent of the resistance of the connection. The locating member can be a continuous resistive wire, preferably coated with a conductive polymer; such a locating member can form part of a sensor cable in which the elongate components of the circuit are in a wrapped configuration, or part of a cable in which the conductors are separated by a member shaped to prevent capillary action of a liquid from connecting the conductors. Alternatively the locating member comprises a plurality of discrete resistors. Preferably the system is arranged so that the sensitivity of the system is not dependent on the location of the fault and/or is such that only connections within a certain range of resistance will activate the system. The voltage drop is preferably calculated by comparing it to the voltage drop over a resistor of known size. Particular event-sensitive connection means are preferably employed for the detection of hydrocarbons and for the detection of acids.

Elongate sensors comprising conductive polymers, and methods and

Devices for detecting and obtaining information about an event

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Palo Alto, CA, United States of America

Laurence M Welsh