DE1959612U - LIGHT BULB WITH THE ADDITION OF GAS-SHAPED HALOGENES, IN PARTICULAR OF BROMINE, TO THE FILLING GAS. - Google Patents

Description

RA. 159 603 * 21: 3.67

Patent-Treuhand-Gesellschaft for electric light bulbs mbH, Munich

Incandescent lamps with an addition of gaseous halogens, in particular bromine, to the filling gas. )

There are incandescent lamps known whose bulb is filled with noble gases Contains addition of halogens. With the help of this addition of halogen, a circular process takes place inside the lamp during operation in which the tungsten particles evaporated from the luminous element and otherwise deposited on the bulb wall at the operating temperature of the lamp vessel converted to the gaseous tungsten halide and transported back to the luminous element. Decompose on the hot filament the tungsten halides turn back into free halogen and tungsten, which is deposited on the luminous element. Incandescent bulbs -with the addition of halogen to the filling gas show no blackening during their entire service life, so their light yield remains during their Operating time almost constant.

The cycle process described can with the halogens iodine, bromine, chlorine and fluorine kept going. When using fluorine as an additive to the lamp filling gas, it is necessary to use the inner bulb wall and also the other components used inside the lamp with a fluorine-resistant coating, such as calcium fluoride or the like, to provide.

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It is difficult to supply the gas required for the cycle Amount of halogen in elemental form "to be added. It is therefore already known to add halogen-containing compounds that can be easily metered into the filling gas and to make the halogens free from these compounds only inside the lamp. Particularly suitable for this Purpose Compounds that produce the free halogens through thermal decomposition on the hot luminous element. Such compounds are for example halogenated hydrocarbons such as dibromomethane and others These substances have a considerable amount even at normal temperature Vapor pressure, but they can easily be measured in the desired amount and added to the filling gas.

In the course of the production process of incandescent lamps with added halogen for The filling gases are the filling gases with the added halogenated hydrocarbon and filled into the lamp bulb at the desired pressure. Wake up closing the lamps by melting the filler neck the halogenated hydrocarbon introduced together with the filler gas is decomposed when the luminous element is put into operation. At the The halogenated hydrocarbon dissociates into hot luminous bodies elemental halogen and hydrogen, furthermore elemental carbon is deposited. At least part of the carbon can be used are deposited on the tungsten filament and form a carbide there. The formation of tungsten carbides on and in the luminous element However, it is highly undesirable because it embrittles the Luminous body enters. In the case of incandescent lamps according to the innovation, this is serious disadvantage eliminated. For their production, halogenated silicon compounds, in particular halogenated ones, are added to the filler gases Silanes, such as dibromosilane, mixed in.

Incandescent lamps with an addition of gaseous halogens, in particular from bromine to the filling gas according to the innovation are characterized that the thermal decomposition of the halogenated silicon compounds added to the filling gas, in particular halogenated silanes, like dibromosilane, deposited layer of elemental silicon on the

Built-in parts and deposited on the inner wall.

In the manufacture of incandescent lamps after the innovation is after the introduction of the filling gas with the addition of, for example, dibromosilane into the lamp bulb and the closing of the bulb The luminous element is heated by the passage of electricity by melting the filler neck. The added is on the hot luminaire Dibromosilane decomposes, whereby elemental silicon is deposited and bromine and hydrogen or hydrogen bromide are released. The elementary silicon is deposited on the built-in parts in the lamp bulb and also on the inside wall of the bulb. When the Tungsten silicides can form on the luminous element. In contrast to the tungsten carbides, however, tungsten silicides cause no "embrittlement of the filament. The service life of the incandescent lamp is therefore not changed disadvantageously.

The deposition of the thermal decomposition of the dibromosilane silicon produced on the inner wall of the piston can be directed so that the coating is deposited in those places where it the light emission and thus the intended use of the incandescent lamp is not impaired. One such point is the lamp dome, for example. The thermal decomposition of the dibromosilane added to the filling gas is controlled by the heating rate of the filament. When the filament temperature is slowly increased, it forms inside the bulb a gas flow which carries with it the majority of the silicon particles formed during the decomposition and with a corresponding The position of the lamp is deposited in the bulb dome.

In the drawing, an incandescent lamp is shown according to the innovation. The lamp bulb made of quartz glass or another high-melting point Glass is denoted by 1. The strips 3 and 4 made of molybdenum foil lead through the pinch 2 into the interior of the lamp. The lamp bulb is melted at 6. At the luminous element 7 this is added to the filling gas, e.g. Argon, added in an amount of a few tenths of a percent at e.g. 0.3 ^ Dibromosilane decomposes. The arrows indicate the heating

of the luminous element through the passage of current with a slow increase in the luminous element temperature. By most of the elemental silicon formed during the decomposition of the dibromosilane is carried to the bulb dome and there deposited at 8.

- Protection claims -

Claims (1)

Protection claims 1. Incandescent lamps with an addition of gaseous halogens, in particular of bromine, to the filling gas, characterized in that * that during the thermal decomposition of the added to the filling gas halogenated silicon compounds, in particular halogenated silicon, such as dibromosilane, deposited coating elemental silicon is deposited inside the lamp on the built-in parts and on the inner wall. Incandescent lamp according to protection claim 1, characterized in that the main amount of the during the thermal decomposition of the filling gas admixed halogenated silicon compounds formed coating of elemental silicon is deposited on the piston dome.