EP1643539A1 - Dielectric barrier discharge lamp with clip - Google Patents

Abstract

The lamp has an electrode (4) fitted to an outside of a discharge vessel (9) along the longitudinal extent of the discharge vessel. The electrode is fitted to the discharge vessel by an interlocking connection with a sleeve (10) surrounding the electrode. The sleeve partially surrounds the circumference of the discharge vessel perpendicular to the longitudinal extent and leaves an aperture free for light radiation purposes. Independent claims are also included for the following: (A) an illumination system having a dielectric barrier discharge lamp (B) a method for producing a dielectric barrier discharge lamp (C) use of a discharge lamp as a UV radiator for the purpose of illuminating a catalyst.

Description

Technical area

The present invention relates to a dielectrically impeded discharge lamp. This is understood to mean discharge lamps in which at least the anodes or, in the case of bipolar operation, also all electrodes are separated by a dielectric layer from a discharge medium in the discharge vessel. As a result, as a result of an electrical charge of the dielectric layer on the anode or the electrode acting as an anode in this phase, an autonomous extinction of the discharge by an internal counterpolarization occurs. The lamp operation is thus ultimately by a dense series of very short discharge flashes.

State of the art

Such dielectrically impeded discharge lamps have been variously known in the art and, due to various advantageous technical characteristics, are of particular interest for the backlighting of display devices, such as computer monitors and television screens, or for office automation applications. In the latter case, elongated rod-shaped lamp shapes are generally used, which can be used to illuminate documents in scanners, fax machines, copiers and the like. Such discharge lamps with a tubular elongate discharge vessel are also already known and available. You can also use it for other applications, for example as a UV emitter for certain technical processes, be of interest. The present invention is not limited to a particular application.

Dielectrically impeded discharge lamps can not be operated with direct current due to the short outlined discharge mechanism, but are operated either with unipolar power supply pulses or with bipolar power supply pulses. The frequencies used are usually in the order of some 10 kHz.

The described tubular elongated discharge lamps have electrodes oriented along the longitudinal extent. This does not necessarily mean that the electrodes must run as simple straight strips parallel to the direction of longitudinal extension. They can also be meandering or structured in a different form, but run overall along the longitudinal extent. The invention relates to discharge lamps in which at least one electrode outside the discharge vessel, d. H. on the outside, is attached. In the prior art, both types with internal electrodes and those with external electrodes are known. External electrodes provide i. d. R. simpler production, but force certain minimum thicknesses of the dielectric layer between the electrode and the discharge medium, because the discharge vessel wall itself serves as such. In principle, variants with internal and external electrodes are conceivable.

It is already known, such electrodes in the case of internal electrodes by dispensing, that is to say painted on, and in the case of external electrodes by gluing or the entire discharge lamp enveloping transparent foil hoses to attach.

Presentation of the invention

The invention is based on the technical problem of specifying a dielectrically impeded discharge lamp with a tubular elongated discharge vessel and at least one electrode attached to the outside of the discharge vessel along the longitudinal extension, in which the electrode is mounted in an advantageous manner. Furthermore, the invention is intended to specify a corresponding illumination system comprising such a discharge lamp with a suitable ballast and a method for producing the discharge lamp.

The technical problem is solved by a dielectrically impeded discharge lamp, in which the electrode is attached to the discharge vessel by positive engagement with a sleeve surrounding the electrode, which sleeve partially surrounds the circumference of the discharge vessel perpendicular to the longitudinal extension, while leaving an aperture for light emission.

Furthermore, the invention relates to a lighting system with such a dielectrically impeded discharge lamp having at one end of the discharge vessel mounted contacts for electrical connection of the lamp, and with an electronic ballast for operating the lamp, with a housing of the ballast fixedly connected to a connector element is that is designed so that the lamp with the contacts having the end can be connected as a complementary connector element by mating with the connector element of the housing to the ballast.

In addition, the invention also relates to a corresponding manufacturing method in which at least one electrode is attached by a positive connection with a sleeve enclosing the electrode to a tubular elongated discharge vessel so that the electrode along the longitudinal extent of the discharge vessel, wherein the sleeve leaves an aperture for light emission.

Advantageous embodiments of the invention are specified in the dependent claims and will be explained in more detail below. The disclosure of the description implicitly refers to both the discharge lamp, the lighting system and the manufacturing method, without explicitly distinguishing between these categories in detail.

The basic idea of the invention is to use a sleeve for mounting the at least one electrode or preferably the two or more external electrodes. Cuff is here referred to a device that has its own sufficient dimensional stability to hold the electrodes by positive engagement. The cuff should therefore be used as a kind of clamp or clamping device. This allows to release an aperture for light emission by the discharge lamp, so that the cuff does not have to be made particularly thin and not transparent. The cuff must also not be glued on. It also allows stabilization and / or protection of the discharge vessel against external influences and can thus contribute to a desired weight reasons and to avoid high voltages desired reduction of the wall thicknesses of the discharge vessel. In particular, the electrode can be mounted on the discharge vessel by simply clipping on or pushing in or into the sleeve, so that the production of the discharge lamp at this point is significantly simplified and accelerated.

In the invention, it is preferred that only the mentioned positive connection holds the electrode, that is, it is not yet adhesively bonded or otherwise fastened to the discharge vessel, and further that the sleeve is biased for this purpose, ie also in the mounted state still maintains a certain contact pressure.

Furthermore, it is also preferred that the sleeve itself is held on the discharge vessel only by positive engagement or force closure as a result of its inherent stability, that is, it bears against itself. So you should also not be glued additionally.

Especially with regard to the already mentioned stabilization and protective function of the sleeve, it is preferred, but within the scope of the invention, not absolutely necessary that the sleeve extends substantially along the entire discharge vessel. It can also be used in one case, one or a plurality of sleeves, which make up only part of the longitudinal extent of the discharge vessel.

Furthermore, the above explanation of the positive locking and the inherent dimensional stability of the sleeve is not to be understood as necessarily having to be in one piece. It is provided in the context of a particular embodiment of the invention, on the contrary, to use an at least two-part cuff. In this case, a functional differentiation can take place, for example in the form of an outer shielding plate and an electrical insulation located therein between at least the electrode and the shielding plate. In such cases, the insulation itself may not necessarily be dimensionally stable, although it should be considered part of the cuff.

Another possibility for a two-part cuff consists in two along the longitudinal extent of the discharge vessel divided and in the assembled state adjoining and firmly connected parts that produce a positive or non-positive connection in the connected state relative to the discharge vessel. Such parts can therefore also be applied without form and force fit to the discharge vessel and then connected to produce the positive or non-positive connection. Particularly suitable are clip connections between the two parts, preferably also non-detachable clip connections. This embodiment is particularly suitable for sleeves, which consist of not substantially elastic material.

The electrode held by the described positive engagement with the sleeve is preferably rod-shaped. This means that it is dimensionally stable and not foil-like. It therefore has an order of magnitude comparable height and width in the cross section to the longitudinal direction, for example, a height and width, which preferably do not differ from each other by more than a factor of 5.

wobei der Faktor F zumindest 1,5, bevorzugt zumindest 2 und besonders bevorzugt zumindest 2,5 beträgt. Zu weiteren Einzelheiten wird verwiesen auf die EP 0 981 831, in der u. a. auch erläutert wird, dass in dieser Beziehung im Fall mehrschichtiger Aufbauten die entsprechende Summe der einzelnen Quotienten aus Dicke und Dielektrizitätszahl verwendet werden muss.It may be important that the sleeve, if it is electrically conductive or contains electrically conductive parts, not too strong capacitive coupling to the electrode (s). If, in the following, the conductive part of the sleeve is turned off, that is to say, for example, the aforementioned shielding plate, it is preferred that an assumed radial thickness d _D between the metallic sleeve and the outer electrode, that is to say the thickness of the mentioned insulation layer within the metal shield , and a dielectric constant ε _{D of} this layer as well as a thickness d _{B of} the dielectric barrier between the electrode and the discharge medium with a corresponding relative permittivity ε _B overall satisfy the relationship: $${\mathrm{d}}_{\mathrm{D}}/{\mathrm{\epsilon }}_{\mathrm{D}}\ge \mathrm{F}\times {\mathrm{d}}_{\mathrm{B}}/{\mathrm{\epsilon }}_{\mathrm{B}}.$$

wherein the factor F is at least 1.5, preferably at least 2 and more preferably at least 2.5. For further details, reference is made to EP 0 981 831, which also explains, inter alia, that in this case, in the case of multilayer constructions, the corresponding sum of the individual quotients of thickness and dielectric constant must be used.

In a further embodiment of the invention, the electrodes are rod-shaped and formed at one end as a plug connection element.

The basic idea of this aspect is to use the external electrodes as plug-in connectors at one end. The electrodes have a certain inherent dimensional stability and thus can be used as a plug connection element, so are not foil electrodes.

The electrodes should be designed so that they are in a mechanically preferably detachable, d. H. can be separated again without fundamental destruction, form can be connected to a complementary connector element. A plug-in connection is understood to mean a frictional connection of largely inherently stable elements taking place while retaining the essential shape of the plug connection elements. Thus, the connector is to be demarcated from, for example, crimp, in which foil-like electrodes are contacted in a significant change in their shape and without taking advantage of dimensional stability.

The use of the electrodes themselves as plug connection elements ensures a simple structure and simplifies the contacting process significantly.

In particular, the electrodes may be simple round rods and either have a pipe end as a so-called female element of the plug connection or terminate as a so-called male element as a round rod. The trained for receiving a round rod tube end as a female connector element can thus be present both on the electrode side and cable or ballast side. Corresponding embodiments are of course possible with other than round cross-sections, the round cross-sectional shape is preferred.

Incidentally, the invention also relates to such discharge lamps, in which the at least two counter-plug connection elements for the described electrode ends are included, which are therefore already provided for example with a cable or packed together with it. Preference is given not only a nondestructive releasable connector, but also a producible via purely translational movement connector. Such connectors are structurally simple and allow a particularly simple contacting method.

Favorable geometric configurations for the plug connection elements on the electrodes or the complementary plug connection elements are designed such that an element at least partially surrounds the complementary one. For example, in the described connection between a rod and a pipe end, the rod end is completely encompassed by the pipe end. However, if a widened flat end of a rod is inserted into a slot of a complementary element, so the flat end is only on two sides, that is only partially encompassed by the complementary element. Here, therefore, it is meant that one element lies "laterally" on at least two sides of the other with respect to the longitudinal direction.

Preferably, the electrode ends to be used as plug-in connection elements project beyond the discharge lamp and are therefore particularly easy to reach for connection to the complementary plug connection elements.

The frequencies used during operation of the discharge lamp are generally of the order of a few 10 kHz, so that such discharge lamps generate interference radiation in EMC-sensitive environments.

Therefore, an embodiment of the sleeve is preferably provided as a conductive metallic shield, which surrounds the discharge vessel partially and leaves an opening angle for light emission, wherein at least one opening angle limiting screen surface of the shield is removed from the discharge vessel at its outermost end by a distance that at least as large as half the average diameter of the discharge vessel is transverse to the longitudinal extent.

Tubular discharge lamps of this type have a so-called aperture along their longitudinal extension, that is to say a longitudinal strip from which light emerges from the lamp. To ensure good efficiency, this aperture should as far as possible not be covered directly by a shield, which is why known shields completely cover the aperture avoiding. However, the lamp then radiates over the entire recessed area in the corresponding solid angle. The screen surface limits the solid angle of this radiation and thus defines an opening angle of the light emission. This opening angle can be optimized for the technically desired application, ie in individual cases, the opening angle can also be significantly smaller than actually possible with a given aperture. In this case, however, the shielding surface would not affect the luminous efficacy at the relevant spatial angle for the application, but would significantly improve the shielding.

The basic idea of this aspect is therefore that the shielding is not limited to a known per se conductive cladding of the discharge vessel outside the opening angle, but that the shield has at least one shield surface, which extends away from the discharge vessel and thereby limits the opening angle. The shield should therefore, so to speak, have a "diaphragm" along at least one lateral boundary of the opening angle. Preferably, corresponding shielding surfaces are provided at both boundaries of the opening angle, but a shielding surface could also be dispensed with, for example if the shielding in the other direction is not essential or has already been given for other reasons, such as by a metallic wall which is present anyway. In this case, the shielding surface does not necessarily have to run along its entire extent along the boundary of the opening angle, that is, does not necessarily extend essentially radially. Preferably, at least its extreme end limits the opening angle. Incidentally, according to the invention, this outermost end is removed from the discharge vessel by at least half the mean diameter of the discharge vessel.

Incidentally, it is also not absolutely necessary for the shield to surround the entire remaining circumference of the discharge vessel apart from the opening angle. Again, by insignificance of EMI radiation in a certain direction or shielding elements provided there anyway, the reasons for a shield are missing and / or there are other structural reasons which make a gap in the shield appear advantageous.

Although the shielding surface according to the invention of the shield can limit the light emission of the lamp and thus define an effective opening angle at least to one side. On the other hand, it is desirable in many cases to take advantage of as much of the emitted light as possible. If one relates the extent of the aperture to the center of the discharge vessel in the cross section to the longitudinal direction and considers this as the opening angle, preferably the light emission opening angle of the shield at the same center point should be greater than that of the aperture. Incidentally, the shielding surface can indeed dim the light emitted by the aperture because the light emission in the lamp also takes place from the aperture closer parts of the inner shell, so that the effective light emission angle of the aperture is greater than the radially considered opening angle.

Furthermore, the shield can also contain other shielding elements in the region of the opening angle in addition to the shielding surface (s), in particular flat shielding parts extending essentially radially in cross section, which further divide the opening angle. Thus, the shield can also be slightly improved in the direction of the light emission. Examples are explained below.

A simple and preferred possibility is to provide at least one, preferably two end base on the lamp, which are dimensioned radially slightly larger than the discharge vessel itself. Then when the shield applied in an adjacent manner to the base and preferably also mounted in this form and is held, is given by the radial difference between the base and discharge vessel of the desired distance.

A further preferred embodiment of the base relates to flats on its cross-sectional shape (perpendicular to the longitudinal extent of the discharge vessel), which are provided in a suitable manner to the shield, such as a correspondingly shaped metal sheet. Then, when the shield is mounted on the pedestals, the orientation of the flattenings allows a correct orientation, that is to say in particular an alignment of an aperture of the lamp, to the opening angle defined by the shield. Of course, the base may also include other locking devices that match the shield. However, it can also alone by the cuff shape, d. H. be given by the positive connection of the shield itself, a locking or clamping action.

A further embodiment of the invention provides for a modular arrangement of individual discharge vessels, which can be operated together as a quasi-uniform discharge lamp. In the case of the already mentioned plug-in connections at the end of rod-shaped electrodes, the electrodes of the individual modules can be plugged together and the cuffs of individual modules could also be connected to each other or configured only adjacent to one another, however, it would also be possible to use a continuous cuff for a plurality of modules. Even without the mentioned connector, this embodiment may be advantageous, for example when the discharge vessels are modularly arranged in the manner described modular and are held by modular or continuous sleeves and thereby continuous external electrodes in the manner according to the invention by the sleeve (s) are held.

Finally, an embodiment of the invention relates to a lighting system with the described dielectrically impeded discharge lamp, in which a plug connection element is fixedly connected to a housing of the ballast, which is designed so that the lamp with the end of the electrode as plug-in elements having end as a complementary connector element Merging with the connector element of the housing can be connected to the ballast.

This has especially advantages for the method for connecting the discharge lamp to the electronic ballast, in which therefore the discharge lamp is inserted as a plug-in connection element in the plug-in element designed to be complementary to the ballast.

The basic idea of this aspect is, as it were, to regard the dielectrically impeded discharge lamp with tubular elongated discharge vessel itself as a plug connection element. For this purpose, the discharge lamp has at one end the illustrated electrode ends as plug-in connection elements for electrical connection and is connected at this end to a suitably designed complementary plug connection element which is connected to the ballast, i. H. whose housing is firmly connected. Of course, while the ballast-side connector element may be connected via a cable to a circuit board of the ballast, but should be created by the connector, a direct mechanical connection between the lamp and ballast.

It is preferred that the ballast-side connector element not only fixed to the housing, but is integrated into the housing. In other words, the connector element should not be a solid attachment. It should therefore be dispensed with a flexible cable between the ballast housing and the lamp in the sense of a flexible mechanical connection between them. It is preferred that the connector element is integrally integrated in the ballast housing, so for example as a recess in a remotely z. B. cuboid housing, in which recess the tubular lamp itself can be inserted with one end. For the sake of illustration, reference is made to the exemplary embodiment.

The ballast-side connector element is preferably a socket, so a female element with respect to the tubular shape of the lamp.

Preferred applications of the discharge lamp according to the invention and the illumination system according to the invention are not only in office automation, but also in UV lamps. Such UV lamps can be used for various technical processes. Of particular interest in the context of this invention is the illumination of catalyst surfaces for photocatalysis of reactions. A preferred example of an application is in air purification, especially in vehicles, such as automobiles. Here air pollutants can be converted by a photocatalytic process and thus eliminated and thus the vehicle interior are supplied with a relation to the outside world qualitatively much improved air.

Brief description of the drawings

Figur 1

zeigt eine schematische perspektivische Ansicht eines erfindungsgemäßen Beleuchtungssystems.

Figur 2

zeigt das Beleuchtungssystem aus Figur 1 bei von dem Vorschaltgerät abgenommener Entladungslampe.

Figur 3

zeigt eine schematische Draufsicht auf das Beleuchtungssystem aus Figur 1.

Figur 4a

zeigt eine schematische perspektivische Ansicht eines Endes der Entladungslampe aus den Figuren 1 - 3 gemäß einer alternativen Ausführungsform.

Figur 4b

zeigt eine Variante zu Figur 4a.

Figuren 5 - 9

zeigen jeweils schematische Frontansichten von Entladungslampen nach alternativen Ausführungsformen.

Figur 10

zeigt eine perspektivische Darstellung einer Variante eines Abschirmblechs der Entladungslampe aus den Figuren 1 3.

Figur 11 1

zeigt eine perspektivische Darstellung einer weiteren Variante eines Abschirmblechs der Entladungslampe aus den Figuren 1-3.

Figuren 12-16

zeigen alternative Ausführungsformen der Entladungslampe in den Figuren 5-9 vergleichbaren Frontansichten.

In the following, the invention will be explained in more detail with reference to embodiments, wherein the individual features may be essential to the invention in other combinations.

FIG. 1

shows a schematic perspective view of a lighting system according to the invention.

FIG. 2

shows the lighting system of Figure 1 with removed from the ballast discharge lamp.

FIG. 3

shows a schematic plan view of the illumination system of Figure 1.

FIG. 4a

shows a schematic perspective view of one end of the discharge lamp of Figures 1-3 according to an alternative embodiment.

FIG. 4b

shows a variant of Figure 4a.

FIGS. 5 to 9

show in each case schematic front views of discharge lamps according to alternative embodiments.

FIG. 10

shows a perspective view of a variant of a shielding plate of the discharge lamp of Figures 1 third

FIG. 11 1

shows a perspective view of a further variant of a shielding plate of the discharge lamp of Figures 1-3.

Figures 12-16

show alternative embodiments of the discharge lamp in Figures 5-9 comparable front views.

Preferred embodiment of the invention

First of all, to illustrate the structure of a typical dielectrically impeded discharge lamp with a tubular discharge vessel, reference is made to the previously mentioned EP 0 981 831. Explanations already given in this document are not repeated below. Instead, the description of the embodiments focuses on the differences with this prior art.

Figure 1 of the present application shows an inventive lighting system with an electronic ballast 1, which is shown here as a simple cuboid. The figure shows only the housing of the ballast 1, which contains the otherwise known per se circuit parts of a ballast for operating a dielectrically impeded discharge lamp. This may in particular be a class E converter.

The figure shows that in the rear region of the right side of the ballast 1 in FIG. 1, a substantially line-shaped dielectrically impeded discharge lamp 2 with two laterally projecting shielding surfaces 3 is inserted. Figure 2 shows a detail of the ballast 1 and the lamp 2 of Figure 1 is a situation in which the lamp 2 is pulled out of the ballast 1. FIG. 3 shows a plan view of the situation from FIG. 1.

It can be seen in FIG. 2 that a base 7 of the tubular lamp 2 projects beyond the shielding surfaces 3 to the left and this cylindrical protruding base 7 has three further extending axially extending electrode ends 4. Further, Figure 2 indicates that the ballast 1 in its right side surface of the otherwise cuboidal housing shape has a matching receptacle receptacle 5 with therein provided female connector elements 6 for the mentioned axial electrode ends 4 of the discharge lamp 2.

The axial electrode ends 4 are left-hand ends of round-rod-shaped electrodes of the lamp 2 in FIGS. 1-3, which will be discussed in more detail with reference to FIGS. 4-9. These electrode ends are inserted according to FIG. 2 together with the base 7 of the discharge lamp 2 projecting beyond the shield surfaces 3 into the described socket 5 with the plug connection elements 6. As a result, as shown in FIGS. 1 and 3, the lamp 2 is not only electrically connected to the ballast 1, but moreover is also firmly mounted on it. The ballast 1 thus serves as a lamp holder. A flexible cable between the lamp 2 and ballast 1 can therefore be omitted.

The part of the lamp 2 extending beyond the shielding surfaces 3 is a plastic base 7 which, together with a second base 8 recognizable in FIGS. 1 and 3, is a tubular glass discharge vessel 9 in a shielding plate having the shielding surfaces 3 and described in more detail below 10 stops. In Figures 2 and 3, the shielding plate 10 is electrically connected to the shielding surfaces 3 with the metallic housing of the ballast 1. This can be done for example by a small pin, not shown in Figures 1 and 2, which rests on the outer periphery of the base 7 and is inserted with this in the socket 5. The shielding plate 10 is insulated from the electrodes with the ends 4 by an insulation layer, not shown here but shown in FIG. This is a plastic layer. This plastic insulation is in the visible in Figures 1 - 3 part of the discharge vessel 9 between the screen surfaces 3, namely the aperture for light emission, not before. The shielding plate 10 forms with the sockets 7 and 8 a sleeve.

In FIG. 4 a, the shielding plate 10 with the shielding surfaces 3 has been omitted for the sake of simplicity. FIG. 4a shows a variant of the mentioned plastic insulation, in the form of a base 11 extending over the lamp length and, incidentally, electrode ends 12 which on the one hand do not extend beyond the base 11 and on the other hand have a tubular shape. These are female connector elements at the electrode ends in contrast to the male connector elements in Figure 2. Accordingly, a not shown complementary ballast male connector elements in a socket comparable to the socket 5 of Figure 2. The electrodes are inserted into matching recesses of the base 11 and are held by him form-fitting manner on the discharge vessel. The pedestal 11 runs over the lamp length and merges into the pedestal (8 in Figures 1 and 3) at the opposite end of the lamp. He is biased by the shield 10 against the discharge vessel 9 and holds it without further action. The discharge vessel 9 is thus a simple gas-filled tube with inner phosphor and reflection layers.

Since here the insulating layer between the electrodes and the shielding plate 10 is formed at the same time as a base corresponding to the base 7 of Figure 2 Thus, the socket does not grip around the entire circumference of the discharge vessel end.

In both cases, the embodiment of Figures 1-3 and Figure 4a, there is a non-positive and positive fit of the shielding plate 10 to the base and the insulation, thus ensuring a mounting connection.

FIG. 4b shows a variant of FIG. 4a in which additional flattenings 13 are provided on the lateral regions of the base 11. These flattenings 13 are provided in complementary form on a shielding plate 10 (not illustrated here) corresponding to FIGS. 1-3, so that a correct orientation of the aperture on the screen surfaces 3 can already be achieved.

The base 7 of Figure 2 may also be configured so that it specifies only at the ends of the discharge vessel 9 a corresponding Abstandsjustage to the shielding plate 10 and the insulation in the axial intermediate region is only loosely inserted.

Of course, the plug connection between the discharge lamp 2 and the ballast 1 shown in FIGS. 1-3 is not obligatory in the invention. Trained as plug-in elements electrode ends can be useful without this feature, for example, if instead of the socket 5 of the ballast 1, a corresponding female connector head of a connecting cable is provided to the electrode ends and optionally similar to the socket 5 to the base 7 and the discharge vessel 9 fits.

FIGS. 5 to 9 show some variants of the discharge lamps according to FIGS. 1 to 4a. In FIG. 5, instead of three electrodes (or electrode ends) 4, as in FIG. 2, only two electrodes 4 are provided here. Both variants are possible. Occasionally, three electrodes are chosen for better light output. For the present invention, these differences not of particular concern. Furthermore, the opening angle between the screen surfaces 3, so the wing-like ends of the sleeve 10 is chosen here slightly smaller. However, this opening angle is still so great that it does not appreciably obstruct the actual light emission from the aperture in the upper region of the section shown in FIG. Nevertheless, these screen surfaces 3 serve to improve the electromagnetic shielding in the lateral direction by leakage fields emerging from the aperture. FIG. 5 illustrates the aperture in that a phosphor layer 14 is shown there, which is interrupted in the region of the aperture.

In contrast to FIG. 5, FIG. 6 again shows three electrodes 4, but the essential difference consists in the fact that the shield surfaces 3 'from FIG. 6 are supplemented here by inwardly angled parts and thus limit an even narrower opening angle. This is still significantly larger than the aperture angle of the aperture relative to the circular center point of the discharge vessel. However, since also the edge regions of the phosphor layer 14 emit light, the outermost regions of the light emission are already dimmed. The shielding effect is, however, improved accordingly.

The angled shape of the screen surfaces 3 'can take account of structural conditions in the environment, such as when the lighting system (in the sense of Figure 1) is to be mounted in an environment with given spatial conditions, or if such a design appears advantageous for assembly purposes. FIG. 1 has already made clear that the shielding plate 10 not only serves to hold the electrodes on the discharge vessel 9, but also stabilizes the assembly of the entire discharge lamp 2 on the ballast 1. If necessary, the shielding surfaces 3 can also be mounted separately, for example, clamped to the ballast 1, plugged or screwed. Incidentally, they can also have an assembly function with respect to components other than the ballast housing.

FIG. 7 shows a further variant of FIG. 5 with a further narrowed opening angle of the shielding surfaces 3, but here with straight shielding surfaces 3. In this case, the base 7 according to FIG. 2 runs around the entire circumference of the discharge vessel 9 and does not save, as in FIG , the aperture off. However, since the base 7 is only attached to the outermost edge, this does not disturb the light emission or hardly.

Figure 8 differs just by this latter feature of Figure 7. Again, the aperture is recessed. It is therefore a base 11 according to FIG. 4.

FIG. 9 differs from FIG. 8 by an additional shielding part 15 in the opening angle of both the shielding surfaces 3 and the aperture. This is configured radially in the illustrated cross-section and otherwise planar and in the perspective view in Figure 10 better visible. It slightly reduces the light emission through the aperture, but additionally improves the electromagnetic shielding in the light emission direction. Such a part 15 may be a cost effective alternative or additional measure to a transparent conductive coating of the aperture, as shown in the already cited EP-font. For clarity, the details of the connector in Figure 10 are omitted.

FIG. 11 shows, in a representation similar to FIG. 10, a variant of the design of the shielding plate 10. Here, the shielding plate 10 with the shielding surfaces when viewed in section basically consists of two concentric semicircles 16 and 17 with substantially different diameters around the center of the circle of the section through the discharge vessel 9 The semicircles 16, 17 face each other with their openings. In contrast to the previous variants, the smaller of the semicircles 16 also shows a significantly greater distance from the discharge vessel 9, which is not shown here. As a result, even the smaller semicircle 16 serves as a reflector, which reflects from the aperture into it (ie to the right in FIG. 11). radiated light into the larger semicircle 17, which in turn reflects the light out of the cuff. This variant offers a significantly poorer light output than the previous examples, but shows a much better EMC shielding.

FIG. 12 corresponds in the illustration to FIGS. 5-9. However, shows an embodiment without shielding. Here, the sleeve is designed as a positive and non-positive plastic sleeve 18, which has corresponding mold recesses for the electrodes 4 and thus holds them on the discharge vessel 9. The previously described shielding effect is omitted here or could be given by a shield without shielding; however, the other benefits of the cuff are also given.

FIG. 13 shows another form 19 of such a sleeve, which is also considerably more solid. It could for example be used for mounting in a corner situation and has matching inclined surfaces with each other right angle, which are designated 20.

FIGS. 14 and 15 show similar variants as in FIG. 13, but with an almost square cross-section of the sleeve 21 and with two in FIG. 14 and three electrodes 4 in FIG.

Finally, FIG. 16 shows a two-part variant of a cuff. In contrast to the bipartite with shielding and insulation here is a plastic sleeve 22 of a left part 22a and a right part 22b constructed, which can be connected via a hinted with 23 separating slot away via clip connections. Both parts 22a and 22b together result in a similar cross-sectional shape as the sleeve 21 of Figures 14 and 15, but neither of the two halves already produces a positive connection or adhesion. The two parts are thus applied from left and right to the discharge vessel 9 and then clipped together via a preferably non-detachable clip connection in the slot 23 and so brought opposite to the discharge vessel 9 to bias. Naturally can be produced with comparable embodiments, other cross-sectional shapes, in particular those as in the other embodiments.

FIG. 16 also illustrates that the electrodes, designated here by 24, can also have other than round cross-sectional shapes.

Claims (17)

Dielectric barrier discharge lamp
with a tubular elongated discharge vessel
and with at least one electrode,
which is mounted along the longitudinal extension of the discharge vessel on the outside of the discharge vessel,
characterized in that the electrode is attached to the discharge vessel by positive engagement with a sleeve embracing the electrode,
which sleeve partially surrounds the circumference of the discharge vessel perpendicular to the longitudinal extent,
but leaves an aperture for light emission. Discharge lamp according to claim 1, wherein at least two electrodes are mounted by positive engagement with the sleeve on the outside of the discharge vessel. Discharge lamp according to claim 1 or 2, wherein the electrode is held exclusively by the positive connection to the discharge vessel. Discharge lamp according to one of the preceding claims, in which the sleeve is biased relative to the discharge vessel. Discharge lamp according to one of the preceding claims, in which the sleeve rests freely on the discharge vessel. Discharge lamp according to one of the preceding claims, in which the sleeve extends substantially along the entire discharge vessel. Discharge lamp according to one of the preceding claims, wherein the sleeve is at least two parts, wherein a part is an outer metallic shield and a part is an electrical insulation between the shield and the electrode. Discharge lamp according to claim 7, wherein for a thickness d _{D of} the insulation between the shield and the electrode, a dielectric constant ε _D thereof, a thickness d _{B of} a dielectric barrier between the electrode and a discharge medium and a relative permittivity ε _{B of} the total, the relationship applies : $${\mathrm{d}}_{\mathrm{D}}/{\mathrm{\epsilon }}_{\mathrm{D}}\ge \mathrm{F}\times {\mathrm{d}}_{\mathrm{B}}/{\mathrm{\epsilon }}_{\mathrm{B}}.$$

where the factor F is greater than 1.5. Discharge lamp according to one of the preceding claims, in which the sleeve is at least in two parts and two parts of the sleeve along the longitudinal extent of the discharge vessel are firmly connected together. Discharge lamp according to one of the preceding claims, wherein the electrode is rod-shaped. Discharge lamp according to one of the preceding claims having at least two rod-shaped electrodes which are mounted along the longitudinal extent of the discharge vessel on the outside of the discharge vessel, wherein the electrodes are formed at one end as a plug connection element. Discharge lamp according to one of the preceding claims with a conductive metallic shield which partially surrounds the discharge vessel and serves as the cuff, wherein at least one shielding surface of the shield is removed from the discharge vessel at its outermost end by a distance which is at least as large as half average diameter of the discharge vessel is transverse to the longitudinal extent. Discharge lamp according to one of the preceding claims, which has a plurality of juxtaposed in the longitudinal direction of extension and jointly operable discharge vessels. Lighting system with a dielectrically impeded discharge lamp according to one of the preceding claims, having at one end of the discharge vessel mounted contacts for electrical connection of the lamp, and with an electronic ballast for operating the lamp, with a housing of the ballast, a connector element is firmly connected, the is designed so that the lamp with the contacts having the end can be connected as a complementary connector element by mating with the connector element of the housing to the ballast. A method for producing a dielectrically impeded discharge lamp according to any one of the preceding claims, wherein at least one electrode is attached to a tubular elongate discharge vessel by positive engagement with a sleeve embracing the electrode so that the electrode lies along the longitudinal extent of the discharge vessel, the sleeve having a Aperture for light emission leaves free. Use of a discharge lamp according to one of Claims 1 to 13 or of a lighting system according to Claim 14 as a UV radiator for illuminating a catalytic converter. Use according to claim 16, wherein the catalyst is for air cleaning in a vehicle.

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