Koninklijke Philips Corporation N.V.

U.S. Phillips Corporation

Hendrik Anton Van Esveld

Ronald Hans Van Der Voort

Jerzy Janczak

Gerardus Marinus Josephus Franciscus Luijks

Johannes Jacobus Franciscus Geijtenbeek

Vincent Fischer

Carsten Deppe

Oscar Jan Deurloo

Jerry Martin Kramer

Tobias Georg Tolle

Robert Alexander Erhardt

Johannes A Van Vliet

Winston Donald Couwenberg

Johan Leopold Victorina Hendrix

Theodorus Gerardus Marinus Maria Kappen

Antonius Arnoldus Duisters

Joseph Leonardus Gregorius Suijker

Francis Jozef Clementina Vandyck

Catharina Johanna Maria Daemen

Vital Louis Elisabeth Bruyndoncx

Theodorus Peterus Cornelis Maria Vos

Jeroen Waltherus Johannes Schoone

Disclosed is a method for driving a gas discharge lamp in at least two operation modes, including the step of applying an alternating voltage to the gas discharge lamp, the alternating voltage having a first polarity during a first time interval and a second polarity opposite to the first polarity during a second time interval. The first time interval and the second time interval are repeated alternately. During a second operation mode, the electrical power being provided to the gas discharge lamp is smaller compared to a first operation mode, and the duration of the first time interval is at least a multiple of the duration of the second time interval.

Method and driving unit for driving a gas discharge lamp

A metal halide lamp includes a discharge vessel surrounded by an outer envelope with clearance and has a ceramic wall which encloses a discharge space filled with a filling comprising an inert gas, such as xenon (Xe), and an ionizable salt. In the discharge space, two electrodes are arranged whose tips have a mutual interspacing so as to define a discharge path between them. The ionizable salt comprises NaI, TlI, CaIand X-iodide wherein X is selected from the group comprising rare earth metals.

Metal halide lamp

A high-pressure discharge lamp has a discharge vessel () enclosing a discharge space () which contains an ionizable filling. The discharge vessel has a first () and a second () mutually opposed neck-shaped portion provided with a pair of electrodes () arranged in the discharge space (). Each electrode is tubular over its entire length. Preferably, the electrodes are free from coils in the discharge space. Preferably, the electrodes extend to outside the discharge vessel. The high-pressure discharge lamp according to the invention is relatively easy to manufacture.

High-pressure gas discharge lamp having tubular electrodes

A high-pressure discharge lamp has a discharge vessel that is enclosed, with an interspace, by an outer bulb. The end of the outer bulb is provided with a lamp cap. The lamp has an ignition circuit including a series connection of a glow starter and an ohmic impedance. The ohmic impedance is formed by a halogen incandescent lamp. The mutual orientation of the glow starter and the ohmic impedance is such that heat produced by the ohmic impedance is at least partly intercepted by the glow starter.

High-pressure discharge lamp

A method and ballast for driving a high intensity discharge (HID) lamp include generating a very high frequency driving signal for the HID lamp, generating a low frequency modulating signal, amplitude modulating the driving signal with the modulating signal at a predetermined low initial modulation level, measuring a lamp voltage across the HID lamp, determining a standard deviation of the lamp voltage, comparing the standard deviation with a predetermined minimum level, if the standard deviation is above the predetermined minimum level, incrementally increasing the modulation level and repeating the amplitude modulating step, the measuring step, the determining step and the comparing step, and if the standard deviation is below the predetermined minimum level, maintaining the amplitude modulation at the determined level.

High frequency electronic ballast

An improved high frequency ballast is disclosed. The high frequency ballast establishes a lamp current for a gas discharge lamp during a starting operation of the gas discharge lamp wherein an operating ampere level of the lamp current facilitates a substantial achievement by the gas discharge lamp of a color specification associated with the gas discharge lamp. Thereafter, during a stable operation of the gas discharge lamp, the high frequency ballast applies a frequency modulation to an operating frequency of the lamp current and/or an amplitude modulation of the lamp current.

The electric high-pressure discharge lamp has tungsten electrodes ( ) in a light-transmitting lamp vessel ( ) which is closed in a gastight manner. The electrodes ( ) comprise an emitter, preferably in the form of an inner coiled-coil ( ), which is loosely retained in a cavity ( ) of a basket ( ) of the electrode ( ). The inner coil ( ) acts as a non-oxidic emitter. The lamp retains its initial light output to a high degree throughout its life.

Electric high-pressure discharge lamp

The high-pressure discharge lamp has an ionizable filling containing mercury, rare gas, dysprosium halide and a second halide chosen from the halides of Tl, Ce, Pr, Nd, Sm and Gd. The lamp has a comparatively low color temperature and a good color rendition, especially also of the color of the skin. The lamp may be used, for example, as a studio lamp for the illumination of indoor scenes.

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Eindhoven, Netherlands

Hendrik Anton Van Esveld