Plantronics, Inc.

Radiodetection Limited

Gas Research Institute

Peter M Flowerdew

David Huddart

Donald L Hore

Andrezej Z Regini

An apparatus for inductive charging a battery. The apparatus includes a housing with a lower surface and a charging surface. A rechargeable device with a rechargeable battery may be placed on the charging surface. The apparatus further includes a controller for driving an oscillator, wherein the controller receives power from a power source. A first charger coil and second charger coil are disposed within the housing and are coupled to the oscillator. The first charger coil and second charger coil create a substantially horizontal magnetic field in the volume of space above the charging surface.

Inductive charging system

A wireless communication system automatically aligns a magnetic induction field to establish a two-way communication link between a stationary base unit located, for example, at a user's work station, and a remote unit worn by the user, for example, as a headset or body pack. At any point in time, the base unit and the remote unit have an arbitrary relative orientation to each other. The base unit senses this orientation, then aligns the magnetic induction field to maintain the communication link with the remote unit. In one embodiment, the base unit preferably includes an aerial array having a number of mutually orthogonal windings. Each winding produces a signal when a magnetic induction field generated by the remote unit passes through the base unit. A selector module selects the longitudinal axis of the winding with the strongest signal as an approximation of a direction vector defining the orientation of the magnetic induction field relative to the base unit. In another embodiment, the base unit preferably includes an aerial array comprising three orthogonal windings disposed about a spherical core. A selector module selects one or more windings for transmitting a magnetic field that rotates in a plane orthogonal, i.e., 'crossed field,' to the direction vector defining the orientation of the received field relative to the base unit.

Vector measuring aerial arrays for magnetic induction communication

Communication systems requiring a user to wear a headset or body pack preferably include small aerials that use ferrite cores to achieve transmission efficiency. Driving such aerials typically requires the use of a transformer to obtain the strongest possible magnetic field where only a limited supply voltage is available. The limited supply voltage is addressed by combining a step-up transformer and an aerial array on a single permeable core. The transformer includes a primary winding and a secondary winding that are wound along the circumference of the circular cross-section of a toroidal core. The aerial array includes a transmit winding and a receive winding. The transmit winding is wound along the diameter of the toroidal core and the receive winding is wound along the circumference of the toroidal core. In one embodiment, the receive winding is divided into two matching halves. The voltages induced in each half of the receive winding are amplified and summed such that voltages induced by the local transmit winding are canceled while those voltages induced from a transmit winding in a second, distant unit are summed. In another embodiment, a plurality of transmit windings are wound on the core for producing fluxes which are summed in the core and generate a single magnetic induction field.

Aerial arrays for magnetic induction communication systems having

A communication link includes a base unit and a remote unit that each include a transmit aerial and a receive aerial. These units communicate via magnetic inductive fields. The transmit aerial may be an array that shapes the field to transmit in front of the base unit to minimize interference between adjacent base units. Transmission from the base unit to the remote unit preferably uses magnetic inductive fields that are orthogonal to the magnetic inductive fields that transmit from the remote unit to the base unit. Accordingly, the aerials include aerials for receiving and transmitting in such orientations. A tri-axial array includes three aerials that are orthogonal to each other to allow the aerials to be driven by currents that are phase shifted and amplitude modulated so that the plane of the field is selectively tilted to maximize coupling between the base unit and remote unit. Such tilting allows the user of the remote unit to move relative to the base unit and maintain maximum coupling.

Aerial arrays for inductive communications systems

Method and apparatus for tracing conductors using an alternating signal

System for detecting the location and orientation of a temporarily

An apparatus and method for determining the position and orientation of a remote object in relation to an observation point comprises a transmitter for sending a magnetic field signal and a receiver for receiving and analyzing the magnetic field signal. The transmitter or the receiver is positioned at the observation point and the other is secured on the remote object. The transmitter has three coils positioned on a ferromagnetic core with their axes mutually orthogonal to each other and connected to a polyphase power to produce a magnetic field around the coils. The coils are connected and energized in pairs to produce a magnetic field rotating about the axis of the third coil. The receiver has three coils positioned on a ferromagnetic core with their axes mutually orthogonal to each other and responsive to the magnetic field produced by the tranmsitter. The receiving coils are connected in pairs to detect the phase relationship and magnitude of the signal to indicate the orientation of the remote body. The transmitter or receiver coils are preferably annular coils wound orthogonally on a homogeneous spherical ferromagnetic core, although other cores may be used such as a hollow cylindrical ferromagnetic core, a ferromagnetic rod core or a ferromagnetic disc core supported in a gimbal mounting with annular coils wound orthogonally thereon.

Growing community of inventors

Bristol, United Kingdom

Peter M Flowerdew