WO2012110074A1

WO2012110074A1 - High-pressure discharge lamp comprising a halogen-containing ignition aid

Info

Publication number: WO2012110074A1
Application number: PCT/EP2011/052104
Authority: WO
Inventors: Yaroslav KALMYKOV; Stefan Lichtenberg
Original assignee: Osram Ag
Priority date: 2011-02-14
Filing date: 2011-02-14
Publication date: 2012-08-23
Also published as: DE112011104885A5

Abstract

The invention relates to a high-pressure discharge lamp (1) comprising an ignition aid, said lamp having a discharge vessel (2) that is closed on two sides and is accommodated in an outer bulb (3) closed on two sides, wherein the discharge vessel has two ends, in which electrodes are fixed, and wherein two current supplies connect the ends of the discharge vessel and the outer bulb. A UV enhancer (10) is accommodated in the outer bulb, wherein said UV enhancer contains gases containing chlorine, bromine and fluorine or a combination of such halogen-containing gases with noble gases.

Description

Title: HIGH-PRESSURE DISCHARGE LAMP WITH HALOGEN-MOUNTED IGNITION

Technical area

The invention relates to a high-pressure discharge lamp according to the preamble of claim 1. Such lamps are in particular high-pressure discharge lamps for general lighting.

State of the art

US ^Pat. No. 5,811,933 and US ^Pat. No. 6,919,686 disclose a high-pressure discharge lamp with a ceramic discharge vessel in which an ignition aid is used. The ignition aid is a so-called UV enhancer.

Further UV enhancers are described, for example, in US Pat. Nos. 5,942,840 and EP 1 298 706. UV enhancers are already known, they are used in quartz or ceramic high pressure discharge lamps. Normally, the UV enhancer is positioned near the discharge vessel within the outer bulb.

15 In contrast, specifically disclosed in EP 554619 for elekt ^¬ clearing loose high intensity discharge lamps and starters in which it comes to using halides that evaporate easily, the discharge in the starter after the breakdown of the actual discharge by electronegative

20 volatile components to extinguish again.

In EP 1 298 706, iodine is used as a source of additional UV emission, in addition to known noble gases such as Ar, Kr, or Xe. There is an additional effect that, if the lamp is hot and can not ignite, the vaporized Iodine in the UV enhancer prevents discharge and thus protects the component, which prevents premature aging. Only when the iodine has cooled, a start is possible again.

DESCRIPTION OF THE INVENTION The object of the present invention is to provide a high-pressure discharge lamp whose ignition takes place reliably.

This is especially true for metal halide lamps, where the material of the discharge vessel is quartz or ceramic.

This object is solved by the characterizing features ^¬ times of claim 1.

Particularly advantageous embodiments can be found in the dependent claims. For reliable ignition of Krypton85-free high-pressure discharge lamps ^¬ UV radiation is used. This is often provided by UV enhancers. For reliable ignition of all high-pressure discharge lamps, UV radiation in the wavelength range <280 nm is required. A lower threshold of about 160 nm results from the transmission range of the discharge vessel (quartz or ceramic). To solve this problem, mercury-containing UV enhancers with radiation in the ^{abovementioned range have been used} , in particular at a wavelength of 254 nm. To reduce the mercury content in high-pressure discharge lamps, UV enhancers without mercury with corresponding UV emission are necessary. For the ignition of high-pressure discharge lamps free electrons must be generated in the discharge vessel. ^¬ forth until this has been achieved by means of radioactive elements such as Krypton85 in the filling gas or thorium-containing electrodes. Field elevations due to metallic ignition aids (eg US Pat. No. 6,198,223) are also possible in the case of ceramics without sodium ^diffusion . Another solution is to UV radiation (eg quartz technology: US 6,806,646; US 7,301,283; Kera ^¬ miktechnologie: US 5, 811, 933; US 5, 942, 840; US 6, 806, 646).

In UV-enhancers with two electrodes are further Bauele ^¬ elements such as a capacitor (US 4,987,344) or even more complex control systems (US 4,721,888) are required in order to limit the current through the UV enhancer. Therefore, the UV enhancers have prevailed, which have only one electrode and use a dielectrically impeded discharge. These UV enhancers are inexpensive and can be contacted directly with a ^¬-ended lamps. There are no additional components required. The counterelectrode is brought from the outside to the discharge vessel of the UV enhancer. Possible are simple solutions, such as the application to the wire or even more complex solutions such as a metallic ring or a metallic stamped part (W02010131574A1). US Pat. No. 5,990,599 even introduces an additional outer bulb under a metallic ring. Electrodeless UV enhancers are also disclosed in the patent literature (eg US Pat. No. 4,812,714A), in which both electrodes lie opposite the outside of the UV enhancer. In addition to the very commonly used mercury-containing UV enhancer (US Pat. No. 4,818,915A), there are patents relating to a gon-filled UV enhancers (US Pat. No. 5,323,087A, US Pat. No. 5,397,259A), but which hardly provide radiation in the range <280 nm. Another patent describes a mercury-free UV enhancer (EP 1 298 706) based on an Xe, Kr or Ar gas filling with iodine additives.

The statements in the following paragraphs describe alternative mercury-free gas fillings with which UV radiation in the required wavelength range can be generated. A mercury-free UV enhancer with radiation fractions <280 nm can be realized with an excimer gas filling. A lower threshold for the wavelength results from the transmission range of the discharge vessel (quartz or ceramic). Quartz achieves a very high transmission for wavelengths> 180 nm. The transmission of quartz drops sharply to about 160 nm. Quartz is impermeable to wavelengths smaller than 160 nm, so that gases for generating UV radiation at wavelengths <160 nm can be excluded. The vessel of the UV enhancer can consist of quartz or of ^another UV-transparent glass. Even solutions with a UV-enhancer, wherein the discharge vessel consists Kera ^¬ mik are possible.

The electrodes can be two-sided, such as th in the patents US 4,987,344A and US 6,392,343B1 shown, be ^¬ squeezed. Capacitive wiring in series with the UV enhancer then ensures that only a small charge current and no current flow through the UV enhancer. It is also possible to realize the UV enhancer electrodelessly as shown in US 4,812,714A. The Main application but is seen in the realization with an electrode, wherein the second electrode is brought from the outside and a dielectrically impeded Entla ^¬ dung is produced (eg, US 5,323,087A). Gas fillings are possible in the UV enhancers based on radiation involving the halogens Cl, Br, or F. These have the advantage over iodine that very much radiant power is emitted in the effective for the ignition UV range. Possible radiation formers are halogen dimers (F2 * 158 nm with radiation fractions> 160 nm, CI 2 * 259 nm, Br ₂ * -> 289 nm with radiation fractions <280 nm) or noble gas halogen excimers (ArCl * -> 175 nm, KrCl * -> 222 nm, ArF * - 193 nm, KrF * -> 249 nm, ArBr * -> 165 nm, KrBr * -> 207 nm). From a manufacturing point of view and for reasons of function, in particular the combinations are interesting, which can be achieved by gaseous components, which offers a further advantage over iodine or mercury. This includes pure chlorine gas Cl ₂ and also, for example, compounds of halogens with hydrogen HCl, HBr, or gaseous halogenated hydrocarbon compounds such as CH ₃ Cl, CHsBr or liquid at room temperature halogenated hydrocarbon compounds with sufficient vapor pressure such as CH ₂ C1 ₂ , CHC I 3 or CH ₂ Br ₂ , CHBr ₃ . Also halogenated silanes (eg H ₂ Cl ₂ Si or SiCl ₄ ) as well as oxides (C10 ₂ , OF ₂ ) or nitrosyl compounds (NOF, NOC1) are possible.

Fluorine can be introduced by compounds such as NF ₃ , SF ₆ or ₂ F ₄ . Fluorohydrocarbons (eg CH ₃ F or CF ₄ ) are also suitable. Elementary bromine Br ₂ , hydrofluoric acid HF and pure fluorine gas F ₂ are so reactive that they can only be used with a greatly increased ^expenditure . An application of Br ₂ is possible only in a UV enhancer without electrodes (see eg US 4,812,714A) because of the corrosive behavior.

It is known that fluorine attacks glass. Therefore, the above-mentioned fluorine compounds may preferably be used only in a ceramic UV enhancer or in a coated glass bulb. To generate the UV radiation of the halogen dimers CI ₂ *, Br ₂ * and F ₂ * is a filling of the UV enhancer with 100% chlorine gas and the other above-mentioned gaseous halogen compounds and compounds with sufficient vapor pressure possible. But even with the addition of unmixed or mixed noble gases (helium, neon, argon, krypton and xenon), the halogen dimer radiation can be generated.

To generate the noble gas-halogen excimers ArCl *, KrCl *, ArF *, KrF *, ArBr * and KrBr *, the gaseous halogen compounds are mixed with the corresponding noble gases. In some cases, combinations of noble gases can also be mixed in here.

The pressure of the filling gas in the UV enhancer is in the range 1 mbar to 1 bar. The intensity of the UV radiation produced typically increases with the filling pressure, so that an upper limit for the pressure results from the ignition voltage of the UV enhancer, which must be designed for the ignition and operating devices of the lamp. Even krypton85-free lamps can be reliably ignited with the aid of a derar ^¬ term UV enhancer.

Compared to the patent US 4,818,915A, which uses mercury in the UV enhancer, the technical teaching presented here is environmentally friendly.

In US 5,323,087 argon is indicated as gas. This hardly emits UV radiation in the interesting spectral range. The UV enhancer presented here emits UV radiation much more strongly and is therefore more effective, which manifests itself in improved maintenance of the lamps.

The vessel of the enhancer is usually made of quartz glass. A metal foil or the like, which acts as an electric ^¬ de, is located in the cavities surrounded by the hollow vessel and is connected by a metal wire with the first actual potential-imparting electrode system or arch wire. A second electrode is positioned ^¬ except half of the vessel so that the arrangement allows for a dielectric barrier discharge (electrode-gas space dielectric electrode). As the outer electrode, for example, a metal wire, a narrow metal foil or a shaped metallic stamped part is suitable (WO2010131574A1). This electrode is connected to the second actual potential-emitting electrode system or hanger wire.

The filling pressure of the gas (cold) should be between 1 mbar and 1000 mbar.

In principle, the realization of UV enhancers with two electrodes is possible, including the installation of more Devices, such as a capacitor (US 4,987,344) or even more complex controls (US 4,721,888) is possible to limit the current through the UV enhancer. In general, however, UV enhancers have prevailed that have only one electrode and use a dielectrically impeded discharge. These UV enhancers are relatively inexpensive. The counterelectrode is brought from the outside to the ^discharge vessel.

Essential features of the invention in the form of a numbered list are:

1. A high-pressure discharge lamp having a starting aid, with a discharge vessel which is underweight body ^¬ placed in an outer bulb, the discharge vessel has two ends ^¬, in which electrodes are mounted, a frame HAL the discharge vessel in the outer bulb tert wherein as an ignition aid a UV enhancer is housed in the outer ^¬ piston, characterized in that the UV enhancer comprises a UV-transparent container, wherein the container encloses a cavity which is filled with a gas, the UV radiation

Radiation can radiate, wherein the gas has a halogen-containing compound of chlorine, bromine and / or fluorine or can form, which emits UV radiation at the start of the lamp in the range 160 to 280 nm.

2. High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the UV enhancer has a single electrode in the cavity. High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the halogen-containing compound is a halogen gas which emits dimer radiation. High-pressure discharge lamp according to claim 1, character- ized in that the container also contains at least one of the noble gases Kr or Ar and the Füllbe ^¬ conditions are selected so that noble gas halogen excimer radiation is formed. High-pressure discharge lamp according to Claim 1, characterized in that the halogen-containing compound is a

Halogen-hydrogen compound or a halogenated hydrocarbon compound is. High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the halogen-containing compound is a liquid at room temperature halogenated Kohlenwas ^¬ serstoffVerbindung with sufficiently high vapor pressure, which corresponds at least to the compounds CH2X2 or CH3X. High-pressure discharge lamp according to claim 1, characterized in that the halogen-containing compound is a halogenated silane, a halogen oxide, or a nitrosyl compound or a gaseous fluorine compound with nitrogen or sulfur. High-pressure discharge lamp according to claim 1, characterized in that the single electrode is replaced by a

Pen, foil or pen with foil in the cavity is reali ^¬ Siert. 9. high-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the discharge vessel has a metal halide-containing filling.

Brief description of the drawings

In the following, the invention with reference to several Ausfüh approximately examples will be explained. The figures show:

Fig. 1 is a high pressure discharge lamp with ignition aid, see matic;

Fig. 2 shows a container of a UV enhancer with filling in ke ramischer embodiment (Figure 2a) and Glaskap sel-form (Figure 2b).

Preferred embodiment of the invention

FIG. 1 schematically shows a metal halide lamp 1, in which a discharge vessel 2 made of PCA is contained in an outer bulb 3 made of quartz glass, which is terminated with a base 4. The discharge vessel 2 has two ends, on which capillaries 5 sit.

The discharge vessel 2 is provided with a metal halide filling, as known per se. It is supported in the outer bulb 3 by means of a frame 6, which has a short frame wire 7 and a long hanger wire 8. On a first capillary 5 or in close proximity to it sits a UV enhancer 10, which is connected to the short frame wire 7 via a feed line 11. Figure 2a shows in detail a container 12 of the UV enhancer 10. The container 12 is in principle a can or cup-like ceramic tube with side wall 13, bottom part 14 and dome 15. The container can also be shaped differently and it can also be made of glass be made. Essential for the invention is that the container has a filling of halogen gas, or halogen gas combined with inert gas, in particular a Penning mixture or argon. The container 12 has a tubular cavity 17 into which an electrode 18 projects from one side, the dome region 15 of the can. The electrode is sealed in the lid 15, for example by means of glass solder. The walls ^¬ re side of the can, the bottom portion 14 of the can is sealed transparent or made of transparent ceramics. The produced in the UV enhancer 10 during ignition UV radiation can leave through the transparent ceramics, if necessary, in particular by a particularly transparent Bo ^¬ or a transparent window in the bottom of the container and so reach the discharge vessel 2, where the filling ionize. In this case, the particularly transparent bottom 14 is aligned so that it points in Rich ^¬ direction towards the discharge vessel.

In any case, the cavity 17 must be large enough to accommodate the single electrode 18, the UV enhancer operating on the dielectrically impeded discharge principle.

The electrode 18 is a pin or preferably a foil, usually made of W or Mo. It has at the outer end 19 a contact wire 11 attached, see Figure 1. Die Electrode 18 is inserted into the cavity 17. Then, a filling gas is introduced into the cavity 17 and the cavity, in particular closed with glass solder.

Alternatively, according to Figure 2b, the container is simply a capsule 20 made of quartz glass with a transparent dome 21. At the other end of the capsule is a pinch 22. There ends the feed line 23. It is connected to a film 24, which is the only electrode up in the Be ^¬ container, so the interior of the capsule 20 extends. The film 24 can in particular also jagged edges aufwei ^¬ sen. Inside, gas is filled again.

A concrete exemplary embodiment of the filling is a UV enhancer, for example of the type described in US Pat. No. 5,323,087, in which krypton with a 0.5% by volume admixture of chlorine gas Cl _{2 is} used as the filling gas. The UV enhancer shows strong UV radiation of the excimer line KrCl * at a wavelength of 222 nm. The cold filling pressure is in the range 500-700 mbar.

Another embodiment of a UV enhancer is realized with krypton and a 1% admixture of dibromomethane (CH2Br2) which emits KrBr * excimer line at a wavelength of 207 nm. The cold filling pressure is in the range 80-120 mbar.

Claims

claims

Radiation can radiate, wherein the gas has a halogen-containing compound of chlorine, bromine and / or fluorine or can form, which emits UV radiation at the start of the lamp in the range 160 to 280 nm. 2. High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the UV enhancer has a single electrode in the cavity.

High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the halogen-containing compound is a halogen gas which emits dimer radiation.

High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the container also contains at least one of the noble gases Kr or Ar and the Füllbe ^¬ conditions are selected so that noble gas halogen excimer radiation is formed.

5. High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the halogen-containing compound a Halogen-hydrogen compound or a halogenated hydrocarbon compound is.

High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the halogen-containing compound is a liquid at room temperature halogenated Kohlenwas ^¬ serstoffVerbindung with sufficiently high vapor pressure, which corresponds at least to the compounds CH2X2 or CH3X.

High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the halogen-containing compound is a halogenated silane, a halogen oxide, or a nitrosyl compound or a gaseous fluorine compound with nitrogen or sulfur.

High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the single electrode is reali ^¬ Siert by a pin, foil or pen with foil in the cavity.

9. high-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the discharge vessel has a metal halide-containing filling.