Abstract: Stator elements each accommodate at least one stator coil (5, 6), and a rotor (2) comprises a permanent magnet (10) which is axially supported by means of at least one axial bearing (11), the rotor (2) having an inner screwthread (12) in which a threaded spindle (13) is engageable. The permanent magnet (10) of the rotor (2) projects beyond the respective outer end (7, 8) of the stator return element (3, 4) at at least one axial end (10a, 10b), in such a manner that in spite of a displacement of the rotor (2) as a result of bearing tolerances of the axial bearing (11) substantially the entire electromagnetic field of the stator coils (5, 6) is linked to the rotor (2).

Abstract: Thin-panel picture display device having a luminescent screen and a large emitting plane electron source, such as a large number of juxtaposed electron propagation ducts operating by means of wall interaction of electrons. By means of an addressing system, electrons extracted from ducts are directed towards desired locations on the luminescent screen. The addressing system comprises a preselection system and a fine-selection system with an intermediate spacer plate of insulating material provided with apertures for passing electrons arranged in between. To provide the possibility of applying large voltage differences across the thickness of the spacer plate, the walls of the apertures are at least partly coated with a coating of a low .delta. material having a low secondary emission coefficient (.delta..sub.max .ltoreq.3.5), particularly Si.sub.3 N.sub.4, AlN, Cr.sub.2 O.sub.3 or Y.sub.2 O.sub.3.

Abstract: An element of an apparatus is magnetized so as to generate a magnetic field pattern around the element. To achieve this, use is made of a magnetizing coil, and the element and the magnetizing coil are moved relative to each other, the magnetizing coil carrying an alternating current of substantially constant amplitude as well as a signal current. Preferably, there is a phase difference between the signal current and an intended magnetic field pattern.

Abstract: Flat-panel type picture display device having a luminescent screen and a large number of electron propagation ducts operating by means of electron wall interaction. Electrons are withdrawn from the ducts by means of an addressing system, whereafter these electrons are directed towards desired locations on the luminescent screen. An apertured spacer plate of electrically insulating material for passing electrons is arranged between the addressing system and the screen. To enable large voltage differences to be applied across the dimension of thickness of the spacer plate, the spacer plate is provided with a high-ohmic layer, or with a pattern of a low-ohmic material, or with an equalization layer at one side and with a low-ohmic layer at the other side, and at least the walls of the apertures are preferably coated with a material having a low secondary emission.

Abstract: In, for example a field emission display, the invention provides the possibility of combining a plurality of sub-substrates that are attached to a larger rear wall, because notably different modes of multiplexing provide a wider positioning tolerance of a sub-substrate with respect to the front plate. Moreover, the different multiplexing techniques lead to a smaller number of connections, even if no use is made of a rear wall supporting of sub-substrates. A plurality of multiplexing techniques provides the possibility of activating a substantially equally large number of pixels of different colours during parts of an image period, so that there is substantially no colour flicker.

Abstract: Deflection unit for a display tube, comprising a coil support (8) with a saddle-type field deflection coil (12) and a yoke ring (14) surrounding this coil. A form-filling adhesive material (extending between the open portions of the field deflection coil as far as the support) is provided in the free space between the support (8) and the yoke ring (14), with which material the support and the field deflection coil are rigidly connected to the inner surface of the yoke ring. Vibrations of the yoke ring, and noise generated by the coil support due to transmission of these vibrations to the support, are substantially prevented, particularly if the adhesive material also has a damping effect, or if a thin layer of visco-elastic material preferably realizing a detachable connection between the adhesive material and the yoke ring is provided between this adhesive material and the yoke ring.

Abstract: A picture display device has a vacuum envelope and is provided with a face plate whose inner side supports a luminescent screen, a rear wall situated at a short distance therefrom, and the space in-between accommodating a plurality of electron sources, which cooperate with a plurality of electron transport duct including dielectric walls fro transporting, through vacuum, the produced electrons towards positions at a small distance from the luminescent screen. The display device further includes means for reducing the effects of undesired charge transfer of the duct walls, which are provided to improve the start-up and/or steady state electron transport conditions. Specifically, the outer sides of the duct rear walls are provided with a conductor to which an initiation potential is applied, which is equal to or higher than the potential applied for producing the electron transport field.

Abstract: A picture display device having a flat vacuum envelope which is provided with a transparent face plate with a luminescent screen and with a rear wall, which display device has an electron supply section with an electron source for emitting electron currents in a direction parallel to the face plate, and an active selection electrode section with first, preselection, electrodes and second, fine-selection, electrodes, located closer to the screen, for directing each electron current towards desired pixels on the luminescent screen. The fine-selection electrodes are divided into groups and corresponding fine-selection electrodes of at least two groups are interconnected in a series or parallel arrangement in such a way that the technology of providing these electrodes is as simple as possible and/or the possible fine-selection electrode patterns are such that the number of required selection drivers can be reduced considerably.

Abstract: A converter for a satellite antenna including a housing (20) accommodating a circuit support (13, 24) and having a hollow waveguide (26) and an RF output (28), both of which can be connected to the circuit support. The manufacturing effort can be reduced in that, together with adapted metallic components (11, 12), the circuit support constitutes a self-contained, fully operable core module (10, 21) which can be built into the housing.

Abstract: A liquid crystal display device (10) capable of displaying dark characters on a light background, for example a paper white type display, having an LC medium (20), such as PDLC material, switchable between a state in which ambient light incident on one side is back scattered towards a viewer and a state in which incident visible light is transmitted through the medium to a light absorber at the other side so that a viewer perceives a dark display, and in which a photovoltaic structure (25) is used as the light absorber for generating an output voltage in response to the visible light transmitted thereto. In equipment such as a portable computer or the like, the generated power can be utilised to supplement a battery power supply (45).

Abstract: A picture display device has a vacuum envelope and is provided with a face plate whose inner side supports a luminescent screen, a rear wall situated at a short distance therefrom, and the space in-between accommodating a plurality of electron sources, which cooperate with a plurality of electron transport ducts including dielectric walls for transporting, through vacuum, the produced electrons towards positions at a small distance from the luminescent screen. The display device further includes means for reducing the effects of undesired charge transfer of the duct walls, which are provided to improve the start-up and/or steady state electron transport conditions. Specifically, the outer sides of the duct rear walls are provided with a conductor to which an initiation potential is applied, which is equal to or higher than the potential applied for producing the electron transport field.

Abstract: In a thermo-tape unit (1) having a supply reel hub (2) and a supply roll (5) of thermo-tape (6) wound on the supply reel hub (2), the thermo-tape has at least one marking stripe configuration (14) at least in its leading area (8), which configuration comprises at least one marking stripe section (15, 16, 17) having a given section dimension (L1, L2, L3) in the longitudinal direction (L) of the thermo-tape (6), and at least one characteristic of the thermo-tape unit (1) is encoded by means of this section dimension (L1, L2, L3) of the marking stripe section (15, 16, 17).

Abstract: A cathode ray tube is provided with an electron gun which comprises a cathode structure which contains an electron-emitting material at an end portion and in which a heating element of bifilarly wound wire is accommodated. Except in the vicinity of the ends of the wire, said wire is provided with an electrically insulating layer (46) whose radius decreases, near the transition between the covered wire and the uncovered ends, by at least 15%, preferably at least 30%. Preferably, the layer (46) having the reduced radius continues for at least 100 .mu.m in the direction of the transition (54). The distance between the transition (54) and the electric connection (61) is smaller than 250 .mu.m, preferably smaller than 150 .mu.m. As a result, the number of uncovered turns between the electric connection (61) and the transition (54) is reduced to below five.

Abstract: Pulse width modulation driver circuitry both limits and regulates the voltage that is applied to a load from a power source which provides a voltage that may far exceed the maximum safe load voltage. The driver circuitry includes a reactive filter coupled to the load, a voltage sensor for sensing the instantaneous voltage across the load, a timer, and a comparator. The reactive filter alternately takes in energy from the power source and discharges it into the load. The voltage sensor, timer, and comparator cooperate with a switch to modulate the application of power to the load and to the reactive filter in response to the instantaneous magnitudes of the load voltage and the power source voltage.

Abstract: The invention relates to a linear actuation device for a control member (1), particularly a valve tappet (1) in a gas or liquid conduit (2), the device including a rotor (7) with an inner screwthread (10) whose rotary movement is convertible into a linear movement of a threaded spindle (5) which is locked against rotation and which is engageable with the inner screwthread (10).In order to achieve that such a device can be realized simply, cheaply and with a high resolution of the linear movement of the control member, the rotor (7) comprises a magnetized rotary body (8) which cooperates with a single-strand electrically energizable stator (13), the angular position of the rotor (7) being adjustable by means of the stator current and the maximum angular rotation of the rotor (7) being smaller than 180.degree..

Abstract: A deep-frying device comprising a reservoir, a discharge channel for discharging fumes, and a converter for converting volatile organic compounds into carbon dioxide and water, has a passage for the admixture of ambient air to the fumes exuded during deep-frying. This provides an improved odour reduction. In the case of upstream admixture additional oxygen is available, as a result of which a more complete conversion is achieved. In the case of downstream admixture, conversion is possible at a higher temperature without a corresponding rise in the temperature of the discharged mixture.

Abstract: The invention relates to a communication system comprising a station (2) for charge metering of a connection point. This station comprises a monitoring circuit (7) for detecting a request for a connection set-up from the connection point (3), either for establishing the absence of a message after a given period of time, or for evaluating the contents of a message that has arrived from the connection point (3) after the request for a connection set-up has arrived, and for rejecting the request for a connection set-up if invalid parameters of the connection point (3) are established.

Abstract: A receiver comprising an antenna array having a number of antenna elements. The antenna array is fed by a feeder. Switching apparatus are arranged for switching at least a first antenna element to the feeder or at least a second antenna element to the feeder. This provides a spatial shift of the antenna array without changing its radiation pattern. This improves the signal level when poor signal reception occurs due to multipath fading.

Abstract: In a cell of a microwave cellular video distribution system, e.g a multichannel video distribution system operating at frequencies of around 29 GHz or 40 GHz, the transmitting antenna is composed of individual antenna sectors (62a,62b,62c . . . ) for transmitting the microwave signal towards different sectors (216a,216b,216c . . . ) of the cell. In accordance with the present invention, a respective monitor (D,R) is present in each of the different sectors (216a,216b,216c . . . ) of each/the cell to monitor the microwave signal transmitted in that sector. The antenna sectors (62a,62b,62c . . . ) are individually fed through controllable feed means (59,60,61) which permit individual control of the power level of the microwave signals transmitted by the individual antenna sectors (62a,62b,62c . . . ), including the switching off of that sector. A feedback coupling (40,44,49) is present between each monitor (R,D) and the controllable feed means (59,60,61) of the respective antenna sector (62a,62b,62c . . .

Abstract: An electronic ballast is provided for converting an AC voltage and current, supplied by a power source such as a power line, to an alternating square-wave voltage and current having the same frequency, for supply to a discharge lamp. The ballast includes at least one capacitor, bridge switches and high-frequency duty-cycle switches. The bridge switches and the high-frequency duty-cycle switches cooperate to successively electrically connect the capacitor in parallel with the power source, electrically connect the capacitor in series with the power source and the discharge lamp, and to regulate the current provided to and from the capacitor to drive the discharge lamp with a desired square-wave voltage and current at the line frequency.