U.S. Philips Corporation

Koninklijke Philips Corporation N.v.

Hanns Ernst Fischer

Hans G Ganser

Gunther Hans Derra

Holger Moench

Dieter Leers

Horst Horster

Rob Snijkers

Holger Joachim Moench

Reinhard Kersten

Guenther Hans Derra

Xaver Riederer

Joseph G Van Lierop

Bernd Engelbrecht

G&uuml;nther Hans Derra

Thomas Kr&uuml;cken

Thomas V Kr&uuml;cken

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 with a cooling arrangement is described, which is characterized in particular in that the lamp can be operated at an increased power, an increase in the temperature of the coldest spot in the lamp interior generating a higher gas pressure, while the cooling arrangement ( ) is constructed and dimensioned such that a devitrification of the lamp bulb and a condensation of the filling gas are substantially prevented at said increased power. A lighting unit with such a high-pressure gas discharge lamp is further described, as is a power supply unit for operating the lamp. This not only considerably improves the spectral properties of the light, but the lamp also operates at a higher operating voltage because of the higher gas pressure, so that a correspondingly higher lamp power is achieved for a given lamp current. On the other hand, given the same lamp power, a weaker current is required, so that the electrodes will have a substantially longer useful life. All this is achieved without any change in the geometry of the lamp.

High-pressure gas discharge lamp with cooling arrangement

A method of and a device for operating a gas discharge lamp which is fed with an alternating voltage or an alternating current and wherein the instantaneous power of the lamp is increased at given time intervals are used to form the electrodes. The value of an operational datum of the lamp which varies in time is continuously or discontinuously measured and the frequency of the alternating voltage or the alternating current (operating frequency) is selected in dependence on the measured values.

Method of and device for operating a gas discharge lamp

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 circuit for operating a high pressure discharge lamp comprising input terminals for connection to a supply voltage source, output terminals for connecting the high pressure discharge lamp, and apparatus, coupled to the input terminals, for supplying an alternating lamp current to the high pressure discharge lamp. The lamp current in each period has a mean value Im. At the start of each period, the lamp current is lowered with respect to the mean value Im so as to allow for stable diffuse attachment on the cathodic phase electrode. The circuit is particularly suited for operating a lamp in an optical projection system.

Long life discharge lamp operating circuit with reduced lamp flicker

A circuit arrangement is provided for operating a high pressure discharge lamp with a lamp current which, in successive periods, has opposite polarities. The lamp is provided with at least two main electrodes being spaced an electrode distance from each other. The circuit arrangement includes input terminals for connection to a supply source, output terminals for connection to the high pressure discharge lamp, and an element, coupled to the input terminals, for supplying the lamp current to the high pressure discharge lamp, which current, in successive periods, has a predetermined shape. The circuit arrangement is provided with an element for detecting a first parameter indicative of the electrode distance and forming a first signal dependent on the first parameter and with an element for reshaping the lamp current, in successive periods, in dependence of the thus formed first signal.

Circuit arrangement for operating a high-pressure discharge lamp

The invention relates to a measuring circuit for detecting the amount of deposited electrode material on the wall of a lamp vessel of a discharge lamp by measuring the power of infrared radiation within a specific wavelength range, comprising a detector for generating an electrical signal constituting a measure for the power of the infrared light in said specific wave length range. According to the invention the measuring is done in a time lapse starting after a predetermined time interval following the extinguishing of the discharge lamp. An increased accuracy of the measurement is thereby realized.

Circuit arrangement for detecting the amount of deposited electrode

A circuit arrangement for operating a high pressure discharge lamp includes input terminals for connection to a supply voltage source and an apparatus coupled to the input terminals for supplying an alternating lamp current to the high pressure discharge lamp. A device (III) is provided for generating a current pulse in each half period of the lamp current. This current pulse has the same polarity as the lamp current and is superimposed on the lamp current in the latter part of a predetermined fraction of the half periods of the lamp current. The circuit substantially suppresses flickering of the discharge arc during lamp operation.

High pressure lamp operating circuit with suppression of lamp flicker

The high pressure mercury discharge lamp comprises a quartz glass lamp vessel (1) having a region (2) surrounding a discharge space (3), spaced-apart tungsten electrodes (4) defining a discharge path (5) disposed in the lamp vessel, and connected to current conductors (6) which extend from the lamp vessel to the exterior and a filling of mercury, rare gas and bromine. The lamp has an operating pressure of at least about 200 bar. The discharge space (3) is spheroidal in shape and has specified dimensions. The lamp consumes a power of 70 to 150 W. The lamp has favourable properties which render the lamp suitable for use in optical systems, e.g. for projection purposes.

High pressure mercury discharge lamp

A high-pressure mercury vapor discharge lamp whose envelope two tungsten electrodes disposed therein of tungsten and a filling containing a rare gas, a quantity of mercury larger than 0.2 mg/mm.sup.3 at a mercury a pour pressure of more than 200 bar and at least one of the halogens chlorine, bromine or iodine in a quantity between 10.sup.-6 and 10.sup.-4 .mu.mol/mm.sup.3. The wall load in operation is higher than 1 W/mm.sup.2.

High-pressure mercury vapor discharge lamp

In a gas discharge lamp having a discharge vessel containing an ionizable gas filling and consisting of a translucent material, which is surrounded at a certain distance by a translucent outer bulb, the discharge vessel has a thermally insulating translucent envelope of a microporous aerogel.

Gas discharge lamp with microporous aerogel

An electrode head for a high-pressure discharge lamp consists of tungsten sheet material formed as a flat or curved plate having an elongated end face having a transverse dimension at least three or five times the plate thickness. As a result the discharge arc terminates practically in pointed form on the electrode end face, and the electrode is heated relatively slightly but has a large surface for thermal emission.

Growing community of inventors

Stolberg, Germany

Hanns Ernst Fischer