Patent Treuhand Gesellschaft Fur Elektrische Gluhlampen Mbh

Patent-treuhand-gesellschaft Fuer Elektrische Gluehlampen Mbh

Patent-treuhand-gesellschaft F. Elektrische Gluehlampen Mbh

Clemens Barthelmes

Andreas Hohlfeld

Axel Bunk

Ralf Seedorf

Thomas Dittrich

Andreas Genz

Dietrich Fromm

Hans-Werner Goelling

Manfred Pilsak

Lothar Vollmer

Jurgen Vom Scheidt

Jurgen Maier

Anna-Maria Frey

Hans Werner Golling

Joachim Dirks

A projection lamp includes a metal halide discharge lamp (1) with a lightansparent discharge vessel (2) in which two electrodes (3) stand opposite one another, which are joined with current leads (5) led to the outside, whereby the discharge vessel contains an ionizable filling including mercury, at least one noble gas, at least one halogen, one rare-earth metal (RE) as well as another metal, niobium, for the formation of metal halides. The addition of metallic niobium provides the lamp with good color reproduction and good arc stability.

Rare earth metal halide lamp including niobium

Metal halide discharge lamp

Metal-halide discharge lamp for photooptical purposes

Metal halide gas discharge lamp for projection purposes

To optimize operating conditions with respect to overall size of a high-psure discharge lamp having a metal halide fill, the wall thickness (d) in millimeters is selected in accordance with a theoretical optimum relationship of d=1.5+0.1.times..cuberoot.P, in which P is the power rating of the lamp, in watts. The optimal theoretical thickness should not vary by more than .DELTA.d=.+-.0.2.times..sup.d, in millimeters, from the theoretical optimal value, with lower power ratings permitting a thinner wall thickness than higher power ratings. Optimizing the wall thickness improves the color rendition index and the light distribution of the emitted light, as well as decreasing the devitrification of the quartz glass of the discharge vessel.

High-pressure discharge lamp with optimized discharge vessel

To prevent electrolytic current flow between adjacent sealing foils (6,7; 15) within a pinch seal (10, 13) at the operating temperature of the pinch seal, in operation of the lamp, the pinch seal is formed with a pinch seal section which has a thickness which is reduced with respect to the pinch seal outside of the region between the foils, for example in form of a slit or a notch or a thin quartz glass web of, at the most, 3 mm thickness. This reduced section, thus, has a resistance which is a multiple of the resistance which the pinch seal, between the foils, would have if the pinch seal would be of uniform thickness throughout its cross section; this reduced section (11, 18) starts at the outer terminal end of the pinch seal (10, 13) and extends up to at least about the ends of the foils (6, 7; 14, 15) proximate to said bulb portion.

High-pressure discharge lamp

With high-pressure discharge lamps, and, more specifically, ultra high-prure discharge lamps, the electrode shafts (4, 5) are located within cylindrical elongated necks (2, 3) of quartz glass extending from the arc tube (1). To prevent adhesion of quartz from the cylindrical elongated necks (2, 3) of the arc tube (1) upon melt-sealing the necks (2, 3) to the electrode shafts (4, 5), the electrode shafts (4, 5) are surrounded by flexible tissue or fabric hoses, tubes or braids (21, 22), made of highly heat-resistant, electrically insulating inorganic material, for example made of quartz fibers. The tissue hose has an inner diameter which corresponds at least to the outer diameter of the eletrode shaft (4, 5) and is not more than 0.5 mm greater than the electrode shaft. Stray molten material from the necks (2, 3) at the junction or transition zone between the arc tube (1) and the respective necks thus cannot adhere to the electrode shafts, and cracking of the quartz glass in the region of the electrode shafts can be avoided.

To make a lamp of quartz or hard glass which has a bulb (10, 22) which does ot have an exhaust tip, for example a metal halide high-pressure discharge lamp or a halogen incandescent lamp, the glass bulb is formed by blow-molding the bulb to the desired shape, then retaining an electrode system having electrodes (14, 14a) to be placed in the bulb, current supply leads (12, 24) extending externally of the bulb, and sealing foils (13, 23) connecting the current supply leads to the electrodes in a holder die (11, 25), introducing the electrodes by moving the holder die towards the bulb, flushing the bulb by introducing and selectively removing flushing gas through an open end of the tube, introducing a measured quantity of a fill substance, such as mercury, an iodide or the like, into the bulb through the open end thereof, and then heating the bulb in the region of the position of the sealing foils and pinch-sealing the bulb. Excess glass is then cut off and the bulb can be supplied with a base. To introduce the fill gas and fill substances, the holder die can be formed with a through-opening through which gas exchange can take place and fill substances, for example in form of pellets or pills introduced. The pinch-sealing can be carried out in two steps, one step pinch-sealing the electrode system but leaving capillary openings (62) adjacent the side walls of the tube to permit gas exchange. The capillaries can then be melted shut by a pointed flame.

Method of making an electric lamp, and more particularly a lamp vessel

To protect tungsten electrode shafts (2, 3; 15, 16) extending into the a rtz glass discharge chamber (13, 27) of a high-pressure discharge lamp from attack by metal halides included in the fill to improve the color rendition of the discharge, the electrode shafts (2, 3; 15, 16) are tightly surronded by small tubes (11, 12; 25, 26) of electrically insulating material, which is highly temperature resistant, located in part within the press seal (10; 23, 24) and fitted against the ends of sealing foils (6, 7; 19, 20) which face the discharge chamber. The tube elements extend at least about 0.5 mm beyond the inner ends of the press seal (10; 23, 24) into the discharge chamber (13, 27) and are formed of a material which has a thermal coefficient of expansion which is not lower than that of quartz glass and not higher than that of tungsten.

High-pressure discharge lamp with corrosion protected electrode leads

In the method for making a reflective coating at the ends of the discharge essel of a high-pressure discharge lamp, the suspension for making the coating includes from 0.5 to 5% by weight of a highly dispersed pyrogenic silicic acid - aluminum oxide mixture, 0 to 5% by weight of acetic acid, 0 to 1% by weight of boric acid, 24 to 55% by weight of water, and zirconium oxide to make up 100% by weight. By using the novel suspension, the previously required process steps of baking and white-burning can be omitted.

Growing community of inventors

Berlin, Germany

Clemens Barthelmes