Patent Treuhand Gesellschaft Fur Elektrische Gluhlampen Mbh

Patent-treuhand-gesellschaft Fuer Elektrische Gluehlampen Mbh

Patent-treuhand-gesellschaft F. Elektrische Gluehlampen Mbh

Osram Sylvania Inc.

Dietrich Fromm

Andreas Hohlfeld

Joachim Arlt

Guenter Soehring

Klaus Stockwald

Dieter Lang

Jurgen Heider

Achim Gosslar

Clemens Barthelmes

Franz Bernitz

Bernhard Altmann

Wolfram Graser

Peter Schade

Jurgen Vom Scheidt

Jurgen Seehawer

Erich Winzerling

Wolf-Jurgen Wagner

Helmut Klingshirn

Richard Ullmann

Juergen Seehawer

A sintered electrode of high-melting metal (for example tungsten) is produced from spherical metal powder having a well defined particle size. The mean particle size is from 5 to 70 &mgr;m. The particle size distribution covers a range from at most 20% below to at most 20% above the mean particle size.

Sintering electrode

Lighting system, comprising a mercury-free metal halide lamp with a light yield of at least 75 lm/W and a color rendition index of at least 75 and an electronic ballast, the electronic ballast impressing a square-wave power supply on the lamp and keeping the power constant. The filling comprises the following components:

Mercury-free metal halide lamp

Start and operation of high pressure discharge lamps, in which a high-frequency starting voltage U.sub.HF and an operating voltage U.sub.B are furnished to the lamp electrodes includes the steps of: 1) turning on the high-frequency starting voltage U.sub.HF at a starting time t.sub.0 to ionize the lamp filling and preheat the electrodes; 2) turning on the operating voltage U.sub.B after a preheating interval .DELTA.t.sub.H, that is, at time t.sub.1 =t.sub.0 +.DELTA.t.sub.H ; and 3) turning off the starting voltage U.sub.HF at time t.sub.2 .gtoreq.t.sub.1, as a result of which the lamp is then operated solely by means of the operating voltage U.sub.B. As a result, the transfer phase for the development of the arc is shortened. Advantageously, the frequency of the starting voltage is selected such that the product of the frequency f of the starting voltage U.sub.HF and the spacing d between the electrodes meets the condition f.multidot.d.gtoreq.50 kHz.multidot.cm. A circuit arrangement for carrying out this method includes an HF ignition device and an operating device, which are each connected to the electrodes of the lamp via a respective switch, and the two switches are actuated by means of timers.

Method and circuit to start and operate high pressure discharge lamps

Metal halide discharge lamp

To prevent attack on electrodes (4, 5) within a discharge vessel (2) by an ionizable metal halide fill, due to spurious or free oxygen arising within the lamp during operation thereof, which oxygen combines with the metal of the electrodes, and is then dissociated in the arc and re-deposited at the hottest part of the electrode, an oxygen removing getter material is introduced into the discharge vessel. Spurious oxygen arises due to emission of oxygen from the glass wall of the discharge vessel, typically quartz glass, and unavoidable contaminants of the fill substance. The getter material is, preferably, phosphorus, boron or aluminum, a halide of the foregoing, a tungsten boron compound, a tin phosphorus compound, or scandium or a rare earth. If the getter is a halide, iodine, bromine or chloride are suitable. The getter may be introduced in quantities of between 0.05 to 0.6%, depending on the getter substances and the fill composition.

High-pressure discharge lamp with a halide fill including life-extending

To prevent bowing of the arc of a high-pressure discharge lamp operated horizontally, the lamp is supplied with alternating current of between 10 kHz and 100 kHz, in which the frequency and wave shape of the alternating current portions of the supply are so selected that standing radial acoustic resonances will be formed within the discharge medium or fill in the discharge vessel, which standing radially directed acoustic resonances suppress or counteract bending of the discharge arc due to convection phenomena.

Method to operate a high-pressure discharge lamp suitable for horizontal

To provide a fill in a low-power, high-pressure discharge lamp, which is capable of emitting light within a warm white light (WDL) color or neutral white light (NDL) color, that is, in the ranges of between about 2600 to 4600K, the fill has a relative relationship of sodium halide to scandium halide between 5:1 and 24:1, a relationship of sodium halide to thallium halide of 25:1 to 73:1, and a heat damming or heat retention or reflection coating (15, 16) is located at the end caps of the generally bulbous discharge vessel to provide for a cold spot temperature (Tc) of at least 800.degree. C., and preferably higher.

Low-power, high-pressure discharge lamp, particularly for general

Low-power, high-pressure discharge lamps, that is lamps having a power rag below and up to about 400 W, have a quartz discharge vessel retaining a metal halide fill which, to obtain a color temperature between 2700.degree. to 3400.degree. C. contains sodium and tin. To prevent deterioration of the electrode head (19; 39; 59), it is formed in essentially cylindrical or frusto-conical outer contour, which has a mass determined by the formula M=i.sub.L .times.(23.+-.8), and is retained on an electrode pin or shaft (17; 38; 58) having a diameter (d) in millimeters ##EQU1## wherein i.sub.L is the effective value of the lamp current in amperes. Preferably, the electrode head (19) extends beyond the end portion of the electrode pin to define a small depression with respect thereto. The particular shape and dimension of the electrode head and the electrode shaft reduces flicker and electrode burning.

Metal halide low-power high-pressure discharge lamp

A high-pressure discharge lamp with metal halide additives and a power in of less than 100W comprises electrodes (4, 5) which have a shank portion (18) adjacent the seal and a second portion (19) which is formed as a coil and faces the discharge. Adjacent turns of the coil portion (19) do not contact one another. Shank (18) and coil (19) are preferably made of a single piece of wire. In the case of a double-ended arc tube (FIGS. 1 and 2) the axis of the coil portion (19) forms a substantially straight line with the shank portion (18). In the case of a single-ended arc tube (FIGS. 3 and 4) the axis of the coil portion includes an angle of 90.degree. with the axis of the shank portion. In order to protect the electrode, and especially the shank portion from corrosion, the shank (18) of the electrode (4, 5) is surrounded by a conical filament (17) of refractory metal e.g. tungston whose turns are lying closely together. Due to the specific shape of the electrode (4, 5), quicker starting of the lamp is achieved, even when the lamp is still warm.

High-pressure discharge lamp with low power input

Discharge lamp energization circuit to operate a discharge lamp 1 over two electronic switches 10, 11, for example high-voltage, high-current switching transistors, which alternately apply a d-c voltage connected across two capacitors 4, 5, in opposite polarity, to the lamp circuit. The capacitors have the same value, and the lamp circuit includes a serially connected inductance. The electronic switching transistors are supplied from a frequency constant square-wave generator 16, at frequency high with respect to power line frequency, for example within the audio or supersonic range, e.g. 7.5 kHz. A separate ignition or starting circuit may be provided or the series inductance 2 and a capacitor 20 connected in parallel with the lamp may form a series resonance circuit tuned to a low odd harmonic (3, 5 7) of the lamp operating frequency.

Discharge lamp energization circuit, particularly for audio and

A high pressure electric arc tube discharge lamp utilizing low power input. he electrode spacing is less than 20 mm and the arc is electrode-stabilized. The arc tube is of isothermal design. The gas fill of the lamp contains a mixture of metal (i) iodides or (ii) iodides and bromides. The metal halides must include at least the halides of sodium and tin. Mercury is preferred as the buffer gas. When operating, the lamp has a low-color temperature, a luminous efficacy of 80 lms/W and a color-rendering index of about 75. It is suitable for use in interior lighting.

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Warngau, Germany

Dietrich Fromm