Abstract: A composite material responsive to mechanical and/or electrical stress comprises at least one substantially non-conductive binder and at least a first electrically conductive filler. The conductivity of the composite material in an unstressed state is related to the conductivity of the at least one substantially non-conductive binder and in a stressed state to the conductivity resulting from the presence of the at least first electrically conductive filler in the composition. The first electrically conductive filler is comprised of magnetite particles in a particle size distribution, and the at least one binder may include an oil, a gel, a wax a gel-wax, gel-ink or mixtures thereof.

Abstract: A polymer composition comprises at least one substantially non-conductive polymer binder and at least first and second electrically conductive fillers, wherein the first electrically conductive filler is comprised of particles having a void bearing structure, and the second electrically conductive filler is comprised of particles which are substantially spherical in shape.

Abstract: A method of controlling the electrical properties of a quantity of magnetite particles comprises the step of oxidising at least some of the quantity of magnetite particles by heating the said quantity of magnetite particles in an oxygen rich environment for a period of time.

Abstract: A pressure sensitive electrically conductive composition comprises a contained quantity of magnetite particles, wherein the quantity of magnetite particles includes a distribution of particle sizes between sub-micron and tens of microns, and wherein the magnetite particles have a plurality of planar faces, adjacent planar faces connected at a vertex, the particles each having a plurality of vertices wherein the magnetite particles are irregular in shape and have a low aspect ratio.

Abstract: Composite Materials A composite material responsive to mechanical and/or electrical stress comprises at least one substantially non-conductive binder and at least a first electrically conductive filler. The conductivity of the composite material in an unstressed state is related to the conductivity of the at least one substantially non-conductive binder and in a stressed state to the conductivity resulting from the presence of the at least first electrically conductive filler in the composition. The first electrically conductive filler is comprised of magnetite particles in a particle size distribution, and the at least one binder may include an oil, a gel, a wax a gel-wax, gel-ink or mixtures thereof.

Abstract: A pressure sensitive electrically conductive composition comprises a contained quantity of magnetite particles, wherein the quantity of magnetite particles includes a distribution of particle sizes between sub-micron and tens of microns, and wherein the magnetite particles have a plurality of planar faces, adjacent planar faces connected at a vertex, the particles each having a plurality of vertices wherein the magnetite particles are irregular in shape and have a low aspect ratio.

Abstract: A pressure sensitive electrically conductive composition comprises a contained quantity of magnetite particles, wherein the quantity of magnetite particles includes a distribution of particle sizes between sub-micron and tens of microns, and wherein the magnetite particles have a plurality of planar faces, adjacent planar faces connected at a vertex, the particles each having a plurality of vertices wherein the magnetite particles are irregular in shape and have a low aspect ratio.

Abstract: An electrical charge storage medium comprises a quantity of first electrically conductive particles contained in a non conductive binder (for example polyurethane). The first electrically conductive particles are magnetite particles. The quantity of magnetite particles includes a distribution of particle sizes between sub-micron and tens of microns, and the magnetite particles have a plurality of planar faces, adjacent planar faces connected at a vertex. The particles each have a plurality of vertices. The magnetite particles are irregular in shape and have a low aspect ratio. Electrical charge storage medium is applied to a non-conductive substrate and contacted by two spaced apart electrodes to sense the change in resistance upon intercation with a volatile organic compound.

Abstract: A pressure sensitive electrically conductive composition comprises a contained quantity of magnetite particles, wherein the quantity of magnetite particles includes a distribution of particle sizes between sub-micron and tens of microns, and wherein the magnetite particles have a plurality of planar faces, adjacent planar faces connected at a vertex, the particles each having a plurality of vertices wherein the magnetite particles are irregular in shape and have a low aspect ratio.

Abstract: A polymer composition comprises at least one substantially non-conductive polymer binder and at least first and second electrically conductive fillers, wherein the first electrically conductive filler is comprised of particles having a void bearing structure, and the second electrically conductive filler is comprised of particles which are substantially spherical in shape.

Abstract: An electrically responsive composite material (1110) specially adapted for touch screen, comprising a carrier layer (1301) having a length and a width and a thickness (1303) that is relatively small compared to said length and said width. The composite material also comprises a plurality of electrically conductive or semi-conductive particles (201). The particles (201) are agglomerated to form a plurality of agglomerates (104, 1403) dispersed within the carrier layer such that each said agglomerate comprises a plurality of the particles (201). The agglomerates are arranged to provide electrical conduction across the thickness of the carrier layer in response to applied pressure such that the electrically responsive composite material has a resistance that reduces in response to applied pressure.

Abstract: A sensor is configured to experience resistance changes in response to an external interaction. The sensor comprises a first layer of a conductive material having a first electrode connected thereto; a second intermediate layer of a material having a resistance sensitive to said external interaction; and a third layer including a first set of fingers interdigitated with a second set of fingers. A second electrode is attached to the first set of fingers and a third electrode is attached to the second set of fingers. The second layer includes a quantum tunnelling composite and provides electrical conduction between the first layer and the third layer. In a preferred embodiment, the first electrode is connected to either one of said second electrode or said third electrode to complete a parallel connection. A method is described for constructing such a sensor.

Abstract: A sensor for, and a method of, generating electrical signals indicating a positional property and an extent property of a mechanical interaction within a sensing zone. The sensor comprises a plurality of conductive layers. At least one conductive layer is a pressure-sensitive conductive layer comprising a quantum tunnelling conductance (qtc) material. Contact between conductive layers is allowed during the absence of a mechanical interaction within said sensing zone. The sensor may be configured to provide a three-terminal sensing functionality or a four-terminal sensing functionality. The sensing zone may be substantially two-dimensional or substantially three-dimensional. The sensor may be substantially flexible or substantially rigid.

Abstract: A detector comprising control circuitry and a sensor in which the detector comprises three layers. The first layer includes a first set of mutually connected electrically conducting elements and a second set of mutually connected electrically conducting elements. The third layer comprises an electrically conducting plane, and the second layer extends between the first and third layers. The electrical conductivity of the second layer varies in accordance with variations in the intensity of the interactions. In a first mode, the control circuit applies voltage between the first and third layers to generate a first current through the second layer, and provides a measurement of the first current. In a second mode, the control circuit applies voltage between the first and second sets of electrically conducting elements to generate a second current through the second layer, and provides a measurement of the second current.

Abstract: A polymer composition comprises at least one substantially non-conductive polymer binder and at least first and second electrically conductive fillers. The first electrically conductive filler is comprised of particles having avoid-bearing structure; and the second electrically conductive filler is comprised of particles which are acicular in shape.

Abstract: An electrically responsive composite material (1110) specially adapted for touch screen, comprising a carrier layer (1301) having a length and a width and a thickness (1303) that is relatively small compared to said length and said width. The composite material also comprises a plurality of electrically conductive or semi-conductive particles (201). The particles (201) are agglomerated to form a plurality of agglomerates (104, 1403) dispersed within the carrier layer such that each said agglomerate comprises a plurality of the particles (201). The agglomerates are arranged to provide electrical conduction across the thickness of the carrier layer in response to applied pressure such that the electrically responsive composite material has a resistance that reduces in response to applied pressure.

Abstract: An electrically responsive composite material is disclosed, along with a method of producing an electrically responsive composite material, a transducer having a substrate for supporting a flowable polymer liquid and a method of fabricating a transducer. The electrically responsive composite material produced is configurable for application in a transducer. The method includes the steps of receiving the flowable polymer liquid and introducing electrically conductive acicular particles (1501, 1502) to facilitate the conduction of electricity by quantum tunneling. Dielectric particles (1505, 1506) are added of a size relative to the acicular particles such that a plurality of these dielectric particles are dispersed between adjacent acicular particles.

Abstract: A sensor for, and a method of, generating electrical signals indicating a positional property and an extent property of a mechanical interaction within a sensing zone. The sensor comprises a plurality of conductive layers. At least one conductive layer is a pressure-sensitive conductive layer comprising a quantum tunnelling conductance (qtc) material. Contact between conductive layers is allowed during the absence of a mechanical interaction within said sensing zone. The sensor may be configured to provide a three-terminal sensing functionality or a four-terminal sensing functionality. The sensing zone may be substantially two-dimensional or substantially three-dimensional. The sensor may be substantially flexible or substantially rigid.

Abstract: A sensor configured to experience resistance changes in response to an external interaction is disclosed. The sensor comprises a first layer of a conductive material having a first electrode connected thereto; a second intermediate layer of a material having a resistance sensitive to said external interaction; and a third layer consisting of a first set of fingers interdigitated with a second set of fingers. The first set of fingers has a second electrode attached thereto whilst the second set of fingers has a third electrode attached thereto. The second layer comprises a layer formed of a quantum tunnelling composite. In a preferred embodiment, the first electrode is connected to one of said second electrode or said third electrode to make a parallel connection. A method for constructing such a sensing device for sensing an external interaction is also disclosed.

Abstract: A detector comprising control circuitry and a sensor, responsive to interactions of varying intensities, comprising three layers. The first layer includes a first set of mutually connected electrically conducting elements and a second set of mutually connected electrically conducting elements. The third layer comprises an electrically conducting plane, and the second layer extends between the first and third layers. The electrical conductivity of the second layer varies in accordance with variations in the intensity of the interactions. In a first mode, the control circuit applies voltage between the first and third layers to generate a first current through the second layer, and provides a measurement of the first current. In a second mode, the control circuit applies voltage between the first and second sets of electrically conducting elements to generate a second current through the second layer, and provides a measurement of the second current.