EP2529389A1

EP2529389A1 - High-pressure discharge lamp having a capacitive ignition aid

Info

Publication number: EP2529389A1
Application number: EP10765422A
Authority: EP
Inventors: Johannes Buttstaedt; Leon Grabinski; Stefan Dunkel; Janbernd Hentschel; Martin Tueshaus; Stefan Lichtenberg; Bernd Koch
Original assignee: Osram GmbH
Current assignee: Osram GmbH
Priority date: 2010-10-08
Filing date: 2010-10-08
Publication date: 2012-12-05
Also published as: CN103109348B; US8664855B2; CN103109348A; US20130181604A1; WO2012045366A1

Abstract

The invention relates to a high-pressure discharge lamp having an ignition aid, having a discharge vessel that is surrounded by gas, wherein the discharge vessel comprises two ends having seals in which electrodes are secured and wherein an ignition aid causes a corona discharge in the surrounding gas. The ignition aid is fitted with tips for that purpose.

Description

Title: High pressure discharge lamp with capacitive starting aid

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 or for photo-optical purposes.

Prior Art From the US 6,198,223 and the US 6,268,698 is known a ^high-¬ pressure discharge lamp with discharge vessel in which an ignition aid is designed as a winding around one end of Entladungsge ^¬ fäßes.

Radioactivity-free lamps require significantly higher ignition pulses than lamps with radioactive substances in the discharge vessel. In general lighting, however, often only one ignition pulse of 4-5 kV is available due to the ignition devices used. In many cases, therefore, ignition aids are used to reduce the ignition voltage of the lamp by auxiliary structures. There are various embodiments of such ignition aids are known in which the electrical potential of one electrode by means of electrically conductive components outside the Entladungsge ^¬ vessel is brought into the vicinity of the counter electrode. For this purpose, a wire, clip or the like is usually wound around the melt, pinch or capillary in the vicinity of the electrode and electrically conductively connected to the power supply of the counter electrode. When the ignition voltage is applied, a dielectrically impeded discharge in the interior of the modified electrode is produced. ren of the discharge vessel, which io ^¬ nisiert the Brennerfüllgas and reduces the ignition voltage, see EP967631.

However, for lamps whose discharge vessel consists of quartz glass or ceramic be ^¬ agreed locations and as a filling ingredient contains sodium, thus constructed Zündhil ^¬ fen result in sodium leakage, if they are electrically lei ^¬ tend connected to one of two power supply lines. The phenomenon of the sodium leakage is be known ^¬ in itself. For the lamp, the loss of sodium from the discharge vessel severely affects the quality of the light, as the color temperature changes significantly and it can even go out.

To prevent sodium leakage, it is possible the ignition ^¬ helpful arrangement PelN to LAD with the electrodes only capacitive, such as described in WO2008154102A2. A major disadvantage of the capacitively coupled ignition aids, however, is that their effectiveness is significantly lower compared to the directly contacted electric ignition aids, so that in ignition pulses in the range of 4-5 kV, the discharge can often not be started.

Presentation of the invention

The object of the present invention is to provide a high-pressure discharge lamp whose ignition is ensured by simple inexpensive means.

This applies in particular to metal halide lamps, wherein the material of the discharge vessel may be ceramic or quartz glass. This object is solved by the characterizing features ^¬ times of claim 1.

Particularly advantageous embodiments can be found in the dependent claims. The invention relates to high-pressure discharge lamps with a discharge vessel made of quartz glass or ceramic, with or without outer bulb. The invention relates in particular to discharge lamps with a discharge vessel made of quartz glass or ceramic - without radioactive admixtures in the discharge vessel a gas-filled outer bulb or completely without outer bulb

which are started with the help of an ignition pulse in the amount of typically 4 to 5 kV. Described is a solution that ensures an effective ignition of such radioactivity-free lamps just at relatively low ignition pulses by a simple, inexpensive construction.

Especially affected are discharge lamps for general lighting, which usually have an evacuated or gas-filled outer bulb and are designed for life of 6000 hours or more.

Such high-pressure discharge lamps are started by means of special ignitors. The ignition DIE ser ignitors are Festge by appropriate standards sets ^¬. The conditions in the discharge vessel (volume, Elect ^¬ clear distance, filling gas filling pressure, Hg amount, amount and type of metal halides) must be coordinated so that the lamp ignites safely at the specified starting conditions. In addition, with increasing the necessary voltage for ignition. This can result in old lamps not starting on conventional ignitors. However, the ignitability must be guaranteed throughout its lifetime. The disclosure of the invention describes a solution which ensures reliable ignition for high-pressure discharge lamps.

The invention is based on the surprising finding that a corona discharge in the surrounding gas can already be produced at a suitably constructed auxiliary ignition arrangement at low ignition voltages, with the aid of which the actual discharge is ignited in the discharge vessel. The previously known ignition aids, equally whether electrically conductively connected to an electrode or capacitively coupled, on the other hand induce a dielectric barrier discharge within the discharge vessel and to require higher ignition voltages than Inventive ^¬ perform as intended.

In WO2008 / 007284 it is described that a discharge in the outer bulb can be produced by the contact of a power supply with the outer bulb filling gas, all other metallic components being insulated from the outer bulb gas. However, the arrangement described is effective only with ignition pulses well above 5 kV. As an example, the publication indicates that the ignition voltage of a corresponding discharge lamp could be reduced from about 23 kV to about 17 kV by the application of the publication.

US Pat. No. 6,622,580 describes that a suitable outer-cylinder filling gas is produced by means of a dielectrically impeded discharge gas. Charge can be excited so that sufficient UV radiation is generated for the ignition of the lamp. Those who are ^¬ but for required ignition voltages ranging from 10 to 20 kV, so that this method of decision-discharge lamps can not be applied, which must start with a starting pulse of 4-5 kV

A prerequisite for the present invention is that the outer bulb of the lamp is filled with a gas which is ge ^¬ suitable to form a corona discharge, eg Ar, Xe or even air but also other gases or gas mixtures. The filling pressure can be between 1 bar and 10 mbar. Alternatively, a discharge vessel can also be operated directly in air, ie without an outer bulb.

A suitable design of an arrangement according to the invention provides that the outside of the end of the discharge vessel mög ^¬ as near to the electrode, an electrically conductive Anord ^¬ voltage is applied, which has one or more very small radii or sharp edges and electrically connected to the current-to ^¬ guide the counter electrode conductively connected (contacted variant). Alternatively, the Zünd ^¬ auxiliary arrangement with a similar arrangement on the other side of the discharge vessel to be electrically connected without contact to one of the two current supply (capacitive coupled variant). Particularly advantageously, the capacitively coupled Va ^¬ riante comes in lamps with sodium-containing filling for use as the other, the effectiveness of the kapa ^¬ zitiv coupled ignition aid by generating a co- is avoided from the ^discharge vessel to a sodium outlet, ronaentladung is significantly improved. A particularly simple form of the invention in the contacted variant, so to apply a thin wire at one ends of the discharge vessel that the Drah ^¬ tendency at the position as close as possible one electrode and the other wire end is connected to the power supply of the Ge ^¬ counterelectrode. Close contact in mittle ^¬ ren region of the discharge vessel is not necessary.

Alternatively, thin sheets or sheets with comb-like or serrated edges may be disposed at one end of the discharge vessel and connected to the power supply of the counter electrode.

As a capacitively coupled variant, a wire is positioned at both ends of the discharge vessel so that each end of the wire is brought as close as possible to an electrode. Alternatively, foils or sheets are arranged and connected to each other at both ends of the discharge vessel as described above.

In addition, an asymmetric structure is possible which provides an arrangement for forming the corona discharge only on one side of the discharge vessel and, on the other side, realizes the most effective possible capacitive coupling.

The invention allows for very simple technical Anord ^¬ calculations that allow discharge lamps with the above-mentioned properties egg safely ignite ignition devices with an ignition pulse of 4-5 kV. It is particularly advantageous in the case of lamps containing sodium in the capacitively coupled variant. The starting aid according to the invention is significantly wirkungsvol ^¬ ler than a similarly constructed conventional ignition aid, since the corona discharge formed at the wire tip already at lower voltages than a dielectrically impeded discharge in the burner interior.

The effectiveness of an ignition aid with crushed burners is often not very high, since the Zündhilfsanordnung must be led around the entire contusion and the Quet ^¬ Schung fills a large cross-sectional area, so that the induced electric fields are small. The presented invention makes it possible to selectively position a metal tip at the location of the smallest distance between the electrode and the firing outside, so that a comparatively large electric field is induced at the metal tip.

In the known designs of ignition aids the distance between the electrode and inner wall surface of the ^discharge vessel in the region of an ignition aid for the effectiveness is critical since in this region a discharge is induces. Particularly in a discharge vessel made of quartz glass, this distance is, however, difficult to produce reproduction ^¬ ible. It follows that the effectiveness of the ignition aid is subject to fluctuations. In the present invention, a discharge is generated outside the discharge vessel. The case relevant ^¬ te distance to the outer wall of the discharge vessel is easy to adjust and easy to keep production technology constant.

The design of the ignition aid is very simple and cost-effective, since, for example, only a thin wire is required. is taken. By attaching the outside of the discharge ^¬ vessel both burner and outer bulb can be prepared by the conventional methods without modification.

The Zündhilfsbauteil touches the discharge vessel only at the ends, so that it is not exposed to such high temperature load, such as components that have contact with the discharge vessel in the central region. In order for the Materi ^¬ alauswahl is simplified.

Since it is preferably a thin wire, the light emerging from the discharge vessel is much less shielded than in other Zündhilfskonstruktio ^¬ NEN.

Essential features of the invention in the form of a nume ^¬ tured list are: 1. High-pressure discharge lamp having a starting aid, with a discharge vessel which is surrounded by gas, insbesonde ^¬ re in that it is either accommodated in an outer bulb, the gas at a cold filling pressure of 10 mbar is filled to 1 bar, or by having no outer bulb, wherein the discharge vessel two

Having ends with seals, in which electrodes are fixed, characterized in that an ignition aid is mounted on at least one seal, wherein the ignition aid has a local field amplifier in the form of a tip or an arc part ^¬ , wherein the ignition aid in the surrounding gas Ko ^¬ Generates rona discharge that emits UV radiation in the discharge vessel. High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the gas is selected from the group noble gases, air, nitrogen or mixtures ^{thereof ¬} , in particular Ar, Xe or air.

High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the ignition aid is a clip having a frame part with four sides and which is mounted on the seal and this at least partially encloses, wherein the frame part at least one tip extends inwards and in mounted state in the direction of discharge volume shows.

High-pressure discharge lamp according to claim 3, characterized ge ^¬ indicates that at least one side of the frame ^¬ part is provided with a plurality of peaks similar to the teeth of a comb.

High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the ignition aid is a wire with a free tip, wherein the free tip ends at the seal outside in the amount of entry of the electrode in the Ent ^¬ charge volume, in particular a holding ^¬ effect on the seal is achieved by an arch member which is U-shaped with two legs and a base part, wherein the arch part is partially bent around the seal. High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the ignition aid is a Federblechteil on which at least one tip is attached. High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the discharge vessel is made of quartz glass and having a metal halide.

High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the ignition aid is galvanically or ka ^¬ pacific coupled.

High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the ignition aid has two parts which are distributed to both seals, wherein the two parts are connected via a connecting wire.

10. high-pressure discharge lamp according to claim 9, characterized in that the ignition aid as a first part has a sleeve on a first seal and the second part of a curved piece of wire, wherein the tip attached thereto at the second Ab ^¬ seal outside in the amount of entry of the electrode in the discharge volume ends.

Brief description of the drawings

In the following, the invention will be explained in more detail with reference to several embodiments. In the figures ^¬ gen:

1 shows a high-pressure discharge lamp with starting aid, ers ^¬ tes embodiment (Fig. La) and Detailan ^¬ view of the clip thereto (Figure lb and lc). 2 is a detailed view of another Ausführungsbei ^¬ game of a clip.

Fig. 3 shows another embodiment of a high-pressure discharge lamp having a starting aid ^¬ (Fig. 3a) and de tailansicht the clip thereto (Fig. 3b);

4 shows another embodiment of a high-pressure ^¬ discharge lamp with ignition aid;

5 shows another embodiment of a high-pressure ^¬ discharge lamp with ignition aid; 6 shows a comparison of the ignitability of lamps with different ignition aid;

7 shows a high-pressure discharge lamp with ignition aid, according to FIG

State of the art.

Preferred embodiment of the invention

Figure 1 schematically shows the basic structure of egg ner high pressure discharge lamp 1 with a starting aid 12. ^¬ be located a discharge vessel 2 of quartz glass, which is housed in an outer bulb. 3 The outer bulb is filled with air at 1 bar cold filling pressure. The outer leads 4 of the discharge vessel, which contact electrodes 14 in the interior, are connected to two frame wires 5 and 6. A short frame wire 5 leads to a ^¬ ers th foil 7 in a pinch 8 of the outer bulb. A long frame wire 6, often called a stirrup wire, leads to a second film 7 in a second pinch 8. The discharge vessel 2 has a filling made of an i nisierbaren gas, usually argon or xenon, mercury and metal halides, as is known per se.

An ignition aid, see Fig. Lb and lc, in the form of a clip 12 is placed as a cuff around a pinch seal 8 of the discharge vessel and connected via an elbow 15 with the hanger wire 6. The clip 12 has a frame part 16 which is shaped like the frame of an image, with two narrow sides 17 and two longitudinal sides 18. On each side sits approximately in the middle of an inwardly pointing into the cavity of the frame resilient tabs 19 and 29 to press the clip against the bruise, as known. The tabs are bent in pairs in opposite directions from the plane of the frame 16. In order to induce a corona discharge in the outer bulb, has the clip in addition, a short piece of wire 20 which is fixed on a bracket 29 which ei ^¬ ne broad side 18 and bent in the direction Entladungsvolu ^¬ men, is attached, and projects in the direction of the discharge volume beyond this , The free tip 22 of the piece of wire induces a corona discharge in the surrounding gas in the outer bulb.

FIG. 2 shows, as an alternative, a clip 12 in which the tabs 29 on the wide sides 18 are cut out directly from the sheet metal with tips 30. These tabs are triangular and their tips point into the middle of the cavity. During assembly, they are bent in the direction of discharge ^¬ volume to cause a corona discharge. In this case, one or both tabs 29 of the broadside can be shaped in this way.

Figure 3a shows an embodiment of a lamp 1 with a slightly different shaped clip 12, wherein the Broad sides 18 are equipped with a plurality of tips 30, which are like the teeth of a comb ^{ineinanderge ¬} rows and protrude inward. FIG. 3b shows a detail of a clip in which only one of the wide sides 18 is provided with such serrations 30.

FIG. 4 shows a high-pressure discharge lamp 35, in which a discharge vessel 36 is provided with two ends 37, which are formed as cylindrical melts. An outer bulb 38 is attached to the ends of the seals. The starting aid 39 is a wire, which is sym metrically ^¬ distributed on both inclusions here. The wire has in each case an approximately U-shaped bent part 40, with two parallel legs 41 and a leg connecting the base 42. In each case a first leg 41, preferably the outside, as possible via an extension ^¬ piece of wire 45 on the outside of the meltdown near the point at which the electrode enters the discharge vessel. The free end of the Longer side ^¬ delay piece of wire 45 terminates at the outer surface of the seal and is preferably designed as a tip. The respective second legs 41 are connected to each other via a connecting piece, which is formed as a sheet 46.

FIG. 5 shows a very similar exemplary embodiment of a lamp 35, in which a sleeve 50 made of sheet metal is fastened to the first seal 37. From the collar 50, a bonding wire 46 goes to the second seal 37, where the wire is wound around the melt analogous to FIG. 4 (FIG. 51) and terminates at the outer surface of the melt close to the point where the electrode enters the discharge vessel entry. Different ignition assist assemblies with fused silica burners without krypton85 at 400 W power were tested for their effectiveness in ignition. For this purpose, the test samples were fired in CCG operation with commercially available ignitor and throttle for 20 seconds. The Zündpulshöhe was thereby adjusted to 3.5 kV, the Ver ^¬ supply voltage is reduced to 198 V. The time was measured from the application of the first ignition pulse to the ignition of the burner by zeitaufgelös ^¬ te measurement of lamp current and voltage (start time). If no ignition took place after 20 seconds, the measurement was aborted.

The following arrangements were compared:

1. without ignition aid (ZH) - discharge vessel without ignition aid, filling gas in outer bulb: air 2. ZH A - contacted ignition aid with wire winding, filling gas in outer bulb: air

3. ZH B - contacted ignition aid with clip and wire, vacuum in the outer bulb

4th invention - contacted ignition aid with clip and wire, filling gas in the outer bulb: air

FIG. 6 shows the effectiveness of the ignition aid per group.

Of the samples without starting aid, none of them started within 20 seconds. With ignition aid arrangement A, 58%, auxiliary ignition arrangement B 13% and with the inventive ignition aid 100% of the samples could be started at the ignition conditions used. The comparison shows that the ignition aid according to the invention by the excitation of a corona ^¬ charge in Außenkolbenfüllgas already at relatively low Ignition voltages lamps can safely start. In particular, an identical ignition aid (ZH B), in which a Koro ^¬ nal discharge is prevented due to the vacuum in the outer bulb, significantly less effective. Figure 7 shows the known from the prior art Lam ^¬ PE 60 with ignition aid ZHA (61). In this case, has the ^discharge vessel 62 as the ends of two crushing or inclusions 63, wherein at the first end 63, a wire winding 64 is attached with multiple wound around the end turns, the winding to the second end 63 is connected via ei ^¬ NEN connecting wire 65th There, the connection ^{wire is} connected to the power supply 66, which protrudes from the pinch 63.

Claims

claims

1. High-pressure discharge lamp with ignition aid, with a discharge vessel, which is surrounded by gas, ^{insbesonde ¬} re by it is either housed in an outer bulb, which is filled with gas at a cold filling pressure of 10 mbar to 1 bar, or by no

Outer piston, wherein the discharge vessel has two ends with seals, in which electrodes are fixed, characterized in that an ignition aid is mounted on at least one seal, wherein the ignition aid has a local field amplifier in the form of a tip or an arc part ^¬ , wherein the Ignition aid generates a Ko ^¬ rona discharge in the surrounding gas, which emits UV radiation in the discharge vessel.

2. High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the gas is selected from the group noble gases, air, nitrogen or mixtures there ^¬ of, in particular Ar, Xe or air.

3. High-pressure discharge lamp according to claim 1, character- ized in that the ignition aid is a clip having a frame part with four sides and which is placed on the seal and this at least partially surrounds, wherein the frame part of at least one tip extends inwardly and in the assembled state points in the direction of discharge volume.

4. High-pressure discharge lamp according to claim 3, characterized ge ^¬ indicates that at least one side of the frame partly provided with a plurality of tips similar to the teeth of a comb.

High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the ignition aid is a wire with a free tip, wherein the free tip ends at the seal outside in the amount of entry of the electrode in the Ent ^¬ charge volume, in particular a holding ^¬ effect on the seal is achieved by an arch member which is U-shaped with two legs and a base part, wherein the arch part is partially bent around the seal.

High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the ignition aid is a Federblechteil on which at least one tip is attached.

High-pressure discharge lamp according to claim 1, characterized ge ^¬ indicates that the discharge vessel is made of quartz glass and having a metal halide.

10. High-pressure discharge lamp according to claim 9, characterized in that the ignition aid as the first part a cuff and as a second part a bo ^¬ genförmiges piece of wire, wherein the tip attached thereto ends at the second seal outside in the amount of entry of the electrode in the discharge volume.