U.S. Philips Corporation

Koninklijke Philips Corporation N.V.

Dieter Leers

Martin Ossmann

Klaus B Lohn

Hans G Ganser

Peter K Bachmann

Hanns Ernst Fischer

Pieter Postma

Rainer Hilbig

Detlef Uwe Wiechert

Robert Peter Scholl

Johannes Baier

Guenther Hans Derra

Peter E Geittner

Horst Dannert

Bernd Rausenberger

Klaus Gawron

Howard J Wilson

Holger Moench

Johannes Martinus De Regt

Bernd Engelbrecht

G&uuml;nther Hans Derra

Achim Gerhard Körber

Hubertus C M Van Den Nieuwenhuizen

The invention relates to a high-pressure gas-discharge lamp, having at least one gastight fused press-seal between a glasslike material and molybdenum, wherein the molybdenum in the fused press-seal is at least partly exposed to an oxidizing environment and at least that part of the molybdenum that is exposed to the oxidizing environment is covered with a coating, and the coating comprises at least one oxide from among FeO, TaO, NbO, AlO, SiO, TiO, ZrO, HfO, and/or one nitride from among TiN, ZrN, HfN, AlN, BN, and/or one carbide from among TiC, ZrC, HfC, VC, NbC, TaC, BC.

High-pressure gas-discharge lamp with improved temperature resistance

A high-pressure mercury vapor discharge lamp has an envelope which contains two electrodes made from tungsten and a filling in a discharge space. The filling essentially consists of mercury, rare gas, and a halogen that is free in the operating condition. The envelope further has a second space.

High-pressure mercury vapor discharge lamp with a space

A high-pressure gas discharge lamp (HID or UHP lamp, or in general lamps with mercury fillings of between approximately 0.05 and 0.5 mg/mm ) is described with at least one electrode ( ) which is provided with a thickened, for example globular portion ( ) at its end lying inside a lamp vessel ( ). This portion is so dimensioned in dependence on operational parameters of the lamp and/or the diameter of the electrode rod that an electrode tip ( ) forms itself independently at said portion during the first hours of operation. This tip grows from the portion until its free end starts melting. The electrode tip is self-adjusting in this manner, so that an optimum electrode interspacing is maintained throughout lamp life. Furthermore, a method of manufacturing such a lamp is described.

High-pressure gas discharge lamp, and method of manufacturing same

A short-arc discharge lamp ( ) is provided with a translucent lamp vessel ( ) which is closed in a gas-tight manner and which is provided with an ionizable fill. A first and a second electrode ( ) are arranged in the lamp vessel ( ) which are each connected to its own current conductor ( ) which extends to outside the lamp vessel. A starting antenna ( ) is arranged near to the lamp vessel, which antenna is connected to a further current conductor ( ). The starting antenna comprises an antenna container ( ) and a further electrode ( ) which antenna container ( ) is closed in a gas-tight manner and contains an ionizable fill, the further electrode ( ) being connected to the further current conductor ( ). This makes it possible to realize a shorter reignition time by means of a higher reignition voltage on the starting antenna while spark-over from the starting antenna ( ) to the lamp vessel ( ) is avoided.

Short-arc discharge lamp with a starting antenna

A circuit arrangement includes a self-oscillating oscillator circuit electrically connected with a series arrangement of a resistor arranged in series with a capacitor. The series arrangement determines the oscillation frequency of the oscillator circuit. The oscillator circuit serves to supply an oscillating supply voltage to an electronic device that exhibits a resonant frequency. A control signal output of the electronic device has a resistive coupling to the series arrangement. The control signal output serves to supply a control signal representative of the oscillation mode of the electronic device.

Circuit arrangement including a self-oscillator circuit

A circuit arrangement for supplying a lamp comprises a piezotransformer. During stationary operation the lamp is supplied via the piezotransformer. During ignition a DC-ignition voltage is generated over the secondary side of the piezotransformer acting as capacitor.

Circuit arrangement for igniting and operating a lamp having piezoelectric transformer

The discharge lamp comprises a piezotransformer and at least one of the lamp electrodes comprises a secondary side of the piezotransformer. Since the piezotransformer functions as a lamp electrode, as a ballast choke and as a transformer, the discharge lamp can be operated by means of a relatively simple and cheap ballast circuit.

Discharge lamp

A circuit for operating a discharge lamp having circut input terminals for connection to a supply voltage source and an inverter coupled to the circuit input terminals for generating an AC voltage at a frequency f from a supply voltage supplied by the supply voltage source. A piezotransformer has transformer input terminals coupled to the inverter output terminals. Terminals for lamp connection are coupled to the inverter output terminals and is provided for detecting whether the lamp has ignited. A protective device is coupled between the output terminals of the inverter and the transformer output terminals so that the inverter is effectively protected against damage due to ignition pulses generated by the piezotransformer.

Discharge lamp operating circuit using piezoelectric transformer and

A circuit arrangement for operating a lamp has circuit input terminals for connection to a supply voltage source. An inverter is coupled to the circuit input terminals for generating an AC voltage with a frequency f from a supply voltage supplied by the supply voltage source and includes inverter output terminals. A piezotransformer has input terminals coupled to the inverter output terminals. Terminals for lamp connection are coupled to the inverter output terminals. A detector detects whether the lamp has ignited. The transformer input terminals are connected to the inverter output terminals only by means of passive components and the inverter comprises means coupled to the detector for changing the frequency f in response to the ignition of the lamp. The circuit arrangement is simple and inexpensive and need not provide a device for switching the piezotransformer out of the circuit after ignition of the lamp.

Inventer-ballast using a piezoelectric transformer

A piezo-electric transformer comprising a piezo-electric body (PEB) including a driving region having input electrodes (1, 3) and at least one driven region having output electrodes (E11). These regions have opposite faces with at least one of the regions comprising a number of sections polarized in a direction perpendicular to the opposite faces and one pole of each section being connected to an opposite pole of another section by electrically conductive elements (2, 1', 2') in such a way that the sections form a series arrangement. These sections are in a very simple way effectively arranged in series, thereby increasing the input impedance of the piezo-electric transformer. Because the sections are polarized in opposing directions the electrically conductive elements can be of a very simple construction which do not require external conduction wires.

Piezo-electric transformer

The invention relates to an antifriction body (3), in particular for a magnetic head (1), whose antifriction surface (4) is provided with an antifriction layer (4) which contains diamond crystals and which is provided by means of a CVD process. Damage to the elements sliding past the antifriction layer is precluded in that the antifriction layer (4) contains hexagonal lonsdaleite crystals.

Antifriction body having an antifriction layer

In an optical fiber based on silicon dioxide with fluorine doping which determines its refractive index profile, at least in the light transmitting core a substance is added that increases the thermal expansion coefficient. The added substance is uniformly distributed at least in the light transmitting core, and reduces the influence of the drawing force F.sub.Z (during drawing of the preform) on the Rayleigh scattering .alpha..sub.R and the wavelength-independent 'c term' losses. Even at high fluorine dopant concentrations, low Rayleigh scattering losses in the range of the material-intrinsic losses pure for silicon dioxide are achieved. The OH-contamination level is also further reduced, and cracks in the collapsed preforms are largely avoided.

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Stolberg, Germany

Dieter Leers