Nokia Corporation

Rocsole Ltd

Pasi Tapani Laakkonen

Tapani Levola

Anssi Lehikoinen

Arto Voutilainen

Pauli Laitinen

Max Lindfors

Lea Myyryläinen

Mika Mononen

An apparatus for determining, by electrical tomography, vertical profile of an electrical property of interest of material(s) in a target volume comprises a measurement probe to be positioned at a plurality of different measurement levels in a target volume and comprising a plurality of measurement elements each having an interface surface. Each interface surface has a size, shape, and rotational position. A measurement path is formed between two interface surfaces as dependent on the sizes, shapes, and rotational positions of the two interface surfaces, and the distance between the two interface surfaces. The locations, rotational positions, shapes, and sizes of the interface surfaces are selected to provide at least two different measurement paths differing from each other in one or more of said sizes of, shapes of, rotational positions of, and distances between the associated interface surfaces.

Electrical tomography for vertical profiling

A method for determining the location of an interface of interest in a target domain, between a free volume of a flowable material and a solid material limiting said free volume, the method involves the steps of providing a mathematical model of the target domain determining, for a plurality of pairs of electrode groups, a characteristic electrical quantity proportional to the capacitance of a capacitor formed by a pair of electrode groups; receiving measurements of the characteristic electrical quantity for a plurality of pairs of electrode groups; adjusting the mathematical model by varying the location of the boundary surface in order to take into account possible wear of the boundary surface so as to reduce the differences between the measured characteristic electrical quantities and those defined by the mathematical model; and determining the location of the interface of interest on the basis of the adjusted mathematical model.

Method and apparatus for determining the location of an interface of interest, and computer program

The specification and drawings present a new apparatus and method for using a three-dimensional (3D) diffractive element (e.g., a 3D diffractive grating) for expanding in one or two dimensions the exit pupil of an optical beam in electronic devices. Various embodiments of the present invention can be applied, but are not limited, to forming images in virtual reality displays, to illuminating of displays (e.g., backlight illumination in liquid crystal displays) or keyboards, etc.

Beam expansion with three-dimensional diffractive elements

A layered light guide structure has a number of planar light guides arranged in a stack to receive a number of different color light beams from the edge of the light guides. Each of the planar light guides has one or more diffractive structures imparted or provided on its upper surface. The diffractive structures on each light guide are configured to diffract light of a particular wavelength range so that they efficiently diffract the guided light within that light guide. The diffractive structure can be one or more keypad symbols such that the layered light guide structure can be used as a keypad. The symbols can be pixelized such that the pixels can have different color patterns. The diffractive structure can also be a simple patch so that the layered light guide structure can be used as a back-light source.

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Ruspp, Finland

Pasi Tapani Laakkonen