WO2008072170A2

WO2008072170A2 - Dielectric barrier discharge lamp

Info

Publication number: WO2008072170A2
Application number: PCT/IB2007/054999
Authority: WO
Inventors: Georg Greuel; Wolfgang Schiene
Original assignee: Philips Intellectual Property & Standards Gmbh; Koninklijke Philips Electronics N.V.
Priority date: 2006-12-15
Filing date: 2007-12-10
Publication date: 2008-06-19
Also published as: WO2008072170A3

Abstract

A robust dielectric barrier discharge (DBD) lamp with internal electrodes is described. The internal electrodes reduce the wall load by charge carrier bombardment of the discharge vessel of the DBD lamp. The internal electrodes are suspended with at least two suspensions attached to the discharge vessel in order to decrease the sensitivity of the DBD lamp with respect to mechanical loads (strikes, oscillations). Further area shaped internal electrode configurations are disclosed enabling an effective use of the discharge volume.

Description

DIELECTRIC BARRIER DISCHARGE LAMP

FIELD OF THE INVENTION

The current invention is related to a dielectric barrier discharge (DBD) lamp and a method for manufacturing a dielectric barrier discharge lamp.

BACKGROUND OF THE INVENTION

In EP 1615258 A2 such a DBD lamp is disclosed. The DBD lamp comprises a discharge vessel having a principal axis, the discharge vessel encloses a discharge volume filled with a discharge gas. The discharge vessel further comprises end portions intersected by the principal axis. There are at least one electrode of a first type and at least one electrode of a second type in the lamp. The electrodes of one type are energized to act as a cathode and the electrodes of other type are energized to act as an anode. The electrodes are substantially straight, elongated and have a longitudinal axis substantially parallel to the principal axis of the discharge vessel. The electrodes are positioned within the discharge volume. The electrodes of at least one type are isolated from the discharge volume by a dielectric layer. The described DBD lamp has the disadvantage that the mechanical instability enhances the danger of early failures reducing the lifetime of the DBD lamp.

SUMMARY OF THE INVENTION It is an objective of the current invention to provide a robust DBD lamp.

The objective is achieved by means of a dielectric barrier discharge lamp, comprising a discharge vessel, the discharge vessel enclosing a discharge volume filled with a discharge gas, - at least one electrode of a first type and at least one electrode of a second type, the electrode of the first type being designed to act as a low voltage electrode and the electrode of the second type being designed to act as a high voltage electrode , the electrodes being positioned within the discharge volume, at least the electrode of the first type or at least the electrode of the second type is at least partly electrically insulated from the discharge volume by at least one dielectric layer and each electrode is suspended from the discharge vessel by means of at least two suspensions.

The insulating dielectric layer on the electrode or electrodes can be a coating of electrically insulating dielectric materials deposited on the surface of the electrodes or a tube made of electrically insulating dielectric material put over the electrode or electrodes. The kind of insulating is mainly determined by means of the geometric structure of the electrodes. An insulating tube can be easily put over a rod like electrode but electrodes with a more complicated geometry can easier be insulated by means of the deposition (sputtering, evaporation, dipping and the like) of insulating materials.

The electrodes can be suspended from the discharge vessel by means of a fixed connection with the discharge vessel or a recess in the discharge vessel where the electrode with or without insulating dielectric layer is placed. A fixed connection of the electrode with discharge vessel can be a gas tight through connection of the electrode through the discharge vessel or the attachment of an insulating dielectric layer provided on the electrode to the discharge vessel. The term fixed connection has not to be understood in a way that a movement of the electrodes within the discharge volume is totally prevented by means of the suspensions. Providing e.g. a meandering electrode in the discharge volume directly behind the through connection working as a spring can be used to reduce the mechanical load of the through connection caused by mechanical excitation of the DBD lamp. The suspension of the electrodes at two or more points reduces the sensitivity of the DBD lamp with respect to mechanical excitation (e.g. shocks, oscillations etc.) in contrast to prior art where only freestanding electrodes (only one suspension) are disclosed. Mechanical excitation causing oscillations can e.g. be induced by means of the discharge during operation of the DBD lamp. Other possible solutions to improve the robustness of DBD lamps as disclosed by the prior art are mechanical stiffer electrodes, whereby mechanically stiffer electrodes means brittle electrodes and/or electrodes with large cross sectional diameter. Brittleness increases the risk of fracture, whereas large diameters increase the optical absorption from the electrodes reducing the efficiency of the DBD lamp. In addition these measures have always to be adapted to the size of the DBD lamp. Providing two or more suspensions neither has the one nor the other disadvantage and it enables a nearly free scalability of the size of the DBD lamp. Further the relative position of the electrode of the first type and the electrode of the second type to each other is fixed in a more reliable way as in the prior art enabling a more reliable and more efficient DBD lamp. The discharge vessel can e.g. be spherical, cylindrical or any other suitable geometric form whereby the material of the discharge vessel is mainly determined by the application of the DBD lamp and the needed transmission properties of the discharge vessel. The discharge vessel can e.g. consist of Quartz, borosilicate glass or other kinds of glass or ceramics with suitable transmission properties. Further phosphors, reflectors, UV-blockers an the like can be provided on the discharge vessel in order to tailor the radiation properties of the DBD lamp as well known by those skilled in the art. If e.g. phosphors are provided on the interior surface of the discharge vessel the use of interior electrodes as proposed by the current invention reduces the aging of the phosphors due to the reduction of the wall load by charge carrier bombardment of the discharge vessel. The reduced wall load also decreases the aging of the material of the discharge vessel itself. Both the reduced aging of the phosphors and the reduced aging of the material the discharge vessel consists of increase the lifetime of the DBD lamp.

In a further embodiment of the current invention the electrode of the first type and the electrode of the second type are at least partly insulated from the discharge volume by at least one dielectric layer.

The electrodes are at least partly electrically insulated from the discharge volume by means of a dielectric, which suppresses abrasion of the electrodes by means of the discharge and additionally gives a protection of the electrodes with respect to corrosion caused by the discharge gas. A ceramic material can be chosen as dielectric enclosure of the e.g. metal electrodes, having a high bandgap, high electrical insulation strength, high radiation threshold, low porosity, and minimum optical absorption at the wavelength of interest. Candidates for dielectric layers are AI2O3, AlN, SiC>2, and other glasses and ceramics characterized by low electrical losses and wide bandgap, or compounds based on these materials. The particular optimum choice is dependent on the electrical input power of the lamp and the emission wavelength of the discharge.

In another embodiment of the current invention the DBD lamp further comprises a principal axis, the discharge vessel further comprising end portions intersected by the principal axis and the electrodes pass the discharge vessel via at least one end portion. The discharge vessel has e.g. a cylinder shape with two circular shaped end portions enclosing the discharge volume. This cylinder symmetrical structure enables a relatively easy mounting of the electrodes in the discharge volume. In addition the stabilization of the electrodes can be done in a rather easy way by fixing the electrodes at the end portions. In another embodiment of the current invention at least a part of the electrode of the first type or at least a part of the electrode of the second type does have an area shape. Area shaped means that the respective part of the electrode is either an essentially two-dimensional (the thickness of the electrode is much smaller than the extension of the electrodes in the two other spatial dimensions) extending plate or the electrode is a grid extending in two spatial dimensions. Further the area shaped part of at least one of the electrodes can be designed in a way that a volume discharge is generated. In contrast to prior art where essentially one dimensional electrodes (rod shaped electrodes with a diameter much smaller than the longitudinal extension of the electrodes) result in area discharge restricted to a plane defined by the longitudinal extension of the electrodes, the use of an electrode with at least a part of the electrode being area shaped do not necessarily have this restriction enabling a higher volume efficiency (light output per discharge volume). The volume efficiency can be further improved if at least a first part of the electrode of the first type and at least a second part of the electrode of the second type have an area shape and the first part of the electrode of the first type extending in the discharge volume is parallel to the second part of the electrode of the second type extending in the discharge volume. Due to the homogeneous electrical field between the electrodes of the first type and the electrode of the second type the whole volume between the electrodes is used for light generation. In the case of plate like electrode the geometry of the plates and the dielectric coating defines the aperture of the DBD lamp. Using grid like area shaped electrodes decreases the shadowing of the discharge volume by means of the electrodes. The grid like area shaped electrodes can either be coated by means of a thin insulating layer provided on the surface of the grid like area shaped electrodes or the grid like area shaped electrodes are embedded in an insulating material. The embedding insulating material can either enclose the grid like area shaped electrodes or the grid like area shaped electrodes are sandwiched between two layers of insulating material (e.g. two glass tubes of different diameter and the grid like area shaped electrodes is stacked between the tubes). In the case the grid like area shaped electrodes are embedded in an insulating material the insulating material has to be transparent with respect to the emitted radiation. In general the parallel orientation of the electrodes of the first type and the second type is not restricted to planar electrodes according to the Euclidean geometry. The area shaped electrodes are embedded in a two dimensional manifold that can be curved.

In a special embodiment the area shaped first part of the electrode of the first type and the area shaped second part of the electrode of the second type are rectangular and the first part of the electrode of the first type and second part of the electrode of the second type are positioned in the discharge volume. The electrodes are arranged like a plate capacitor.

In a further embodiment of the current invention the electrode of the first type comprises a first rod and at least one first area shaped part, and the electrode of the second type comprises a second rod and at least one second area shaped part and the first area shaped part and the first rod enclose an angle bigger than 45° and the second area shaped part and the second rod enclose the same angle bigger than 45° as the first rod and the first area shaped part. The area shaped parts of the electrode of the first type and the area shaped parts of the electrode of the second type are arranged in alternating way that means that up to the area shaped parts of the electrodes at the boundary of the electrode configuration, each area shaped part of the electrode of the first type is sandwiched between two area shaped parts of the electrode of the second type whereby the distance between the area shaped parts of the electrodes is the same. If the area shaped parts of the electrodes extend perpendicular to the rods the electrode configuration equals a stacked plate capacitor, whereby the area shaped parts of the electrodes equal the capacitor plates and the rods provide the connection between the area shaped parts enabling an effective use of the discharge volume if the shape of the area shaped parts of the electrodes is adapted to the geometry of the discharge volume (e.g. circular area shaped parts of the electrodes arranged perpendicular to the principal axis of a cylindrical discharge volume).

In another embodiment of the current invention the dielectric layer of the electrode of the first type and the dielectric layer of the electrode of the second type are connected with each other by means of a stabilization structure. Fixing the relative position of the electrode of the first type and the electrode of the second type simplifies the mounting of the DBD lamp. The positioning of the electrodes relative to each other is fixed and is not determined by means of the through connection of the electrodes through the discharge vessel as described in prior art. The fixation of the relative position of the electrodes to each other enables a more efficient operation in comparison to the cited prior art where a single suspension does not guarantee a parallel alignment of the electrodes.

The stabilization structure or if more than one stabilization structure is provided at least one of the stabilization structures can also be used to suspend the electrodes from the discharge vessel by connecting the stabilization structure with the discharge vessel. The stabilization structure is used as an additional suspension. This measure is particularly of advantage with respect to big DBD lamps reducing the sensitivity with respect to mechanical loads.

It is further an objective of the current invention to provide method for manufacturing a robust DBD lamp. The objective is achieved by means of a method of manufacturing of a dielectric barrier discharge lamp, the method comprising the steps of: providing a discharge vessel, enclosing a discharge volume in the discharge vessel, providing at least one electrode of a first type and at least one electrode of a second type, the electrodes of the first type being designed to act as a low voltage electrode and the electrodes of the second type being designed to act as high voltage electrode positioning the electrodes within the discharge volume, at least partly insulating at least the electrode of the first type or at least the electrode of the second type from the discharge volume by providing at least one dielectric layer on the electrode of the first type or the electrode of the second type, - suspending each electrode by means of at least two suspensions and filling the discharge volume with a discharge gas. The method for manufacturing has the advantage that the production steps of arranging the electrodes with respect to each other and the positioning of the electrodes in the discharge vessel can be separated. This can be done by suspending the electrodes from at least a first part of the discharge vessel in a first step such that a movement of the electrodes with respect to each other is inhibited. These fixed electrodes are then positioned in a second part of the discharge vessel and the first and the second part of the discharge vessel are connected with each other. A simple example is a cylindrical discharge vessel with two end portions. The electrodes are suspended from the end portions and the suspended electrodes with the end portions are slided in the tube like part of the discharge vessel and the end portions and the tube are connected with each other (e.g. by fusing) in a subsequent step.

The DBD-lamp according to the invention can be used in a wide area of applications. Preferably the lamp is used in a system being used in one or more of the following applications: fluid and/or surface treatment of hard and/or soft surfaces, preferably cleaning, disinfection and/or purification; liquid disinfection and/or purification, beverage disinfection and/or purification, water disinfection and/or purification, wastewater disinfection and/or purification, drinking water disinfection and/or purification, tap water disinfection and/or purification, production of ultra pure water, gas disinfection and/or purification, air disinfection and/or purification, exhaust gases disinfection and/or purification, cracking and/or removing of components, preferably anorganic and/or organic compounds cleaning of semiconductor surfaces, cracking and/or removing of components from semiconductor surfaces, cleaning and/or disinfection of food, cleaning and/or disinfection of food supplements, cleaning and/or disinfection of Pharmaceuticals and/or photochemical synthesis. One advantageously application is the purification or in general the cleansing. Destroying unwanted microorganisms and/or cracking unwanted compounds and the like by means of ultraviolet (UV) radiation do this. By this essential function of that DBD-lamp the above mentioned applications can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be explained in greater detail with reference to the figures, in which the same reference signs indicate similar parts, and in which:

Fig. 1 shows two perpendicular cross-sections of a first embodiment of a DBD lamp according to the current invention.

Fig. 2 shows two perpendicular cross-sections of a second embodiment of a DBD lamp according to the current invention. Fig. 3 shows two perpendicular cross-sections of a third embodiment of a DBD lamp according to the current invention and a detailed view one electrode.

Fig. 4 shows two perpendicular cross-sections of a fourth embodiment of a DBD lamp according to the current invention and a detailed view one electrode.

Fig. 5 shows two perpendicular cross-sections of a fifth embodiment of a DBD lamp according to the current invention.

Fig. 6 shows a cross section of a sixth embodiment of a DBD lamp according to the current invention.

DETAILED DESCRIPTION OF EMBODIMENTS In Fig. 1 a cylindrical discharge vessel 1 made of quartz comprising two end portions 7 and 8 is shown. The discharge vessel 1 has a principal axis 6 being the axis of the cylindrical discharge vessel 1. The left part of Fig. 1 shows a cross section of a DBD lamp enclosing the principal axis and the right part of Fig. 1 shows a cross section of the DBD lamp perpendicular to the principal axis. Within the discharge volume 2 bounded by the discharge vessel a rod like electrode of a first type 3 and a rod like electrode of the second type 4 extend parallel to the principal axis 6. Both electrodes are electrically insulated from the discharge by a hollow quartz tube building the insulating dielectric layer 5. The electrode of the first type 3 passes the discharge vessel 1 at the first end portion 7 on the left side of the discharge vessel and extends up to the second end portion 8 on the right side of the discharge vessel. The quartz tube is attached to the first end portion 7 and to the second end portion 8 building a first and a second suspension 10 stabilizing the electrode of the first type at two points. The electrode of the second type 4 passes the discharge vessel 1 at the second end portion 8 on the right side of the discharge vessel and extends up to the first end portion 7 on the left side of the discharge vessel. The quartz tube is attached to first end portion 7 and to the second end portion 8 building a third and a fourth suspension 10 stabilizing the electrode of the second type at two points. Alternatively one electrode without insulating quartz tube can provide the suspensions 10 on its own by passing e.g. the first end portion 7 and being directly attached to the second end portion. Due to the rod like structure of the electrodes the discharge is limited to the area defined by the electrode of the first type 3 and the electrode of the second type 4. The quartz tube of the electrode of the first type 3 is melted to the quartz discharge vessel at the left end portion 7, and the quartz tube 5 covering the electrode 4 is melted to the quartz discharge vessel at the right end portion 8. The other two suspensions of the electrodes can be realized by either melting of the inner quartz tubes to the discharge vessel, or by forming a recess into the end portion 7 and 8, taking up the free end of the inner tubes. In Fig. 1, the recess in the end portion is shown, providing suspension to the free end of the quartz tube.

In Fig. 2 again a cylindrical discharge vessel 1 made of quartz comprising two end portions 7 is shown. The discharge vessel 1 has a principal axis 6 being the axis of the cylindrical discharge vessel 1. The left part of Fig. 2 shows a cross section of a DBD lamp enclosing the principal axis and the right part of Fig. 2 shows a cross section of the DBD lamp perpendicular to the principal axis. Within the discharge volume 2 bounded by the discharge vessel two rod like electrodes of the first type 3 and two rod like electrodes of the second type 4 extend parallel to the principal axis 6. All electrodes are placed into quartz tubes building the insulating dielectric layer 5. The electrodes of the first type 3 pass the discharge vessel 1 at the first end portion 7 on the left side of the discharge vessel and extend up to the second end portion 8 on the right side of the discharge vessel. The quartz tubes of both electrodes of the first type are melted to the first end portion 7 and fixed at the second end portion 8 building four suspensions 10 whereby two suspensions 10 stabilize one electrode of the first type. The electrodes of the second type 4 pass the discharge vessel 1 also at the first end portion 7 on the left side of the discharge vessel and extend up to the second end portion 8 on the right side of the discharge vessel. The quartz tubes are melted to the first end portion 7 and fixed at the second end portion 8 again building four suspensions 10, whereby two suspensions 10 stabilize one electrode of the second type. Further an electrically insulating stabilization structure 9 is shown being a disk with four through holes where the electrodes pass the stabilization structure fixing the electrodes relatively to each other and with respect to the discharge vessel. The stabilization structure 9 builds an additional suspension 10 for each electrode. Looking at the right side of Fig. 2 showing the cross section perpendicular to the principal axis 6 and the rod like electrodes the rod like electrodes are arranged in an regular pattern of two columns and two rows whereby the electrodes of the first type 3 and the electrode of the second type 4 are arranged in an alternating order in each column and each row defining four discharge areas.

Increasing the number of electrodes of the first type 3 and the number of electrodes of the second type 4 can enlarge this regular pattern of electrodes. Fixing the 4 inner insulating quartz tubes to the right end portion 8 of the lamp can be done either by melting, or by making recesses in the end portion 8, taking up the free end of the quartz tubes, thus acting as a mechanical support.

In Fig. 3 a cylindrical discharge vessel 1 made of quartz comprising two end portions 7 is shown. The discharge vessel 1 has a principal axis 6 being the axis of the cylindrical discharge vessel 1. The left part of Fig. 3 shows a cross section of a DBD lamp enclosing the principal axis and the right part of Fig. 3 shows a cross section of the DBD lamp perpendicular to the principal axis. Below the cross sections of the DBD lamp the electrode of the first type 3 is depicted in more detail. Within the discharge volume 2 bounded by the discharge vessel the electrode of the first type 3 comprises a rod like through connection and a rectangular planar area shaped first part 13 electrically connected to the rod like through connection passing the discharge vessel via the first end portion 7 and the electrode of the second type 4 comprises a rod like through connection and a rectangular planar area shaped second part 14 electrically connected to the rod like through connection passing the discharge vessel via the second end portion 8. Both electrodes are covered with an insulating dielectric layer 5. The suspensions 10 are built as a standard electrical feed through in quartz. The free ends of the electrodes 13 and 14 are fixed to the respective end portion 7 and 8 by a recess in the end portions 7 and 8, as discussed in context with Fig. 1. The planar parts of both electrodes are arranged like a plate capacitor resulting in a homogeneous electrical field with the consequence that the whole volume between the planar first part 13 of the electrode of the first type 3 and the planar second part 14 of the electrode of the second type 4 is used for the discharge increasing the volume efficiency of the DBD lamp.

The structural features of the embodiment of the DBD lamp according to the current invention shown in Fig. 4 with respect to the discharge vessel 1 and the end portions 7 and 8 are the same as discussed in context with Fig. 1 - Fig. 3. The electrode of the first type 3 comprises a first rod and first area shaped parts 23. The area shaped parts 23 have a circular shape and are electrically connected with the first rod. The first rod and the first area shaped parts 23 enclose an angle of 90°. The electrode of the second type 4 comprises a second rod and second area shaped parts 24. The area shaped parts 24 have also a circular shape and are electrically connected with the second rod. The second rod and the second area shaped parts 24 enclose an angle of 90°. The first rod and the second rod are arranged parallel to the principal axis 6 such that up to the area shaped parts of the electrodes at the boundary of the electrode configuration, each area shaped part 23 of the electrode of the electrode of the first type 3 is sandwiched between two area shaped parts 24 of the electrode of the second type 4 whereby the distance between the area shaped parts is the same. Both electrodes are covered with an insulating dielectric layer 5. The first rod of the electrode of the first type 3 extends through the first end portion 7 and the second rod of the electrode of the second type 4 extends through the second end portion 8 providing the electrical contacts of the DBD lamp. By means of electrically insulating stabilisation structures 9, the electrodes form one electrode configuration that can be fixed with respect to the discharge vessel whereby each stabilization structure builds an additional suspension 10 for each electrode. The sandwiched structure of the area shaped parts 23 of the electrode of the first type 3 and the area shaped parts 24 of the electrode of the second type 4 (that means area shaped part 23, insulating dielectric layer 5, part of the discharge volume, insulating dielectric layer 5, area shaped part 24, insulating dielectric layer 5, part of the discharge volume, insulating dielectric layer 5, area shaped part 23 etc.) enables an economic use of the discharge volume by adapting the size of the circular area shaped parts 23, 24 to the diameter of the cylindrical discharge vessel.

The structural features of the embodiment of the DBD lamp according to the current invention shown in Fig. 5 with respect to the discharge vessel 1 and the end portions 7 and 8 are the same as discussed in context with Fig. 1 - Fig. 3. The electrode of the first type 3 is rod like extending along principal axis 6. Further the electrode of the first type 3 passes the discharge vessel 1 at the first end portion 7 on the left side of the discharge vessel and extends up to the second end portion 8 on the right side of the discharge vessel. An insulating dielectric layer 5 deposited on top of the electrode of the first type 3, which is attached to the first end portion 7 and to the second end portion 8, building a first and a second suspension 10 stabilizing the electrode of the first type. The electrode of the second type 4 comprises a rod like part and a grid structure 34 with cylindrical symmetry. The rod like part of the electrode of the second type 4 passes the discharge vessel 1 at the second end portion 8 on the right side of the discharge vessel 1. The electrode of the second type 4 is also covered with an insulating dielectric layer 5 whereby the electrode of the second type 4 is attached to the second end portion 8 building the first suspension of the electrode of the second type 4. An insulating stabilization structure 9 is attached to the grid structure 34 of the electrode of the second type 4, building the second suspension 10 of the electrode of the second type 4. The grid structure 34 of the electrode of the second type 4 is arranged in a cylinder symmetrical way around the rod like electrode of the first type 3. This electrode configuration enables an economic use of the discharge volume 2 by adapting the diameter of the cylindrical grid structure 34 to the diameter of the cylindrical discharge vessel 1. Further the grid structure 34 reduces the shadowing by means of the electrode of the second type 4.

In Fig. 6 a cross section of a spherical DBD lamp according to the current invention is depicted. The spherical discharge vessel 1 consists of two parts. A first part fused with the insulating layers 5 being quartz tubes put over the electrode of the first type 3 and the electrode of the second type 4 and a second part with two recesses building the second suspensions 10 of the electrode of the first type 3 and the electrode of the second type 4. The relative position of the electrodes is further fixed by a stabilization structure 9 being a quartz disk fused with the insulating quartz tubes of the electrodes. The electrodes, the first part of the discharge vessel 1 and the stabilization structure 9 are bonded to each other in a first manufacturing step building one electrode module. In a subsequent step the electrode module is slided-in the second part of the discharge vessel as shown in Fig. 6 and the two parts of the discharge vessel are fused together.

The present invention will be described with respect to particular embodiments and with reference to certain drawings, but this is not to be construed in a limiting sense, as the invention is limited only by the appended claims. Any reference signs in the claims shall not be construed as limiting the scope thereof. The drawings described are only schematic and are non- limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes. Where the term "comprising" is used in the present description and claims, it does not exclude other elements or steps. Where an indefinite or definite article is used when referring to a singular noun, e.g. "a" or "an", "the", this includes a plural of that noun unless specifically stated otherwise.

Furthermore, the terms first, second, third and the like in the description and in the claims are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances, and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

Moreover, the terms top, bottom, first, second and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other orientations than described or illustrated herein.

Claims

CLAIMS:

1. A dielectric barrier discharge lamp, comprising a discharge vessel (1), the discharge vessel (1) enclosing a discharge volume (2) filled with a discharge gas, at least one electrode of a first type (3) and at least one electrode of a second type (4), the electrode of the first type (3) being designed to act as a low voltage electrode and the electrode of the second type (4) being designed to act as a high voltage electrode, the electrodes (3, 4) being positioned within the discharge volume

(2), - at least the electrode of the first type (3) or at least the electrode of the second type (4) is at least partly electrically insulated from the discharge volume

(2) by at least one dielectric layer (5) and each electrode (3, 4) is suspended from the discharge vessel (1) by means of at least two suspensions (10).

2. A dielectric barrier discharge lamp according to claim 1, wherein the electrode of the first type (3) and the electrode of the second type (4) are at least partly insulated from the discharge volume (2) by at least one dielectric layer (5).

3. A dielectric barrier discharge lamp according to claim lor 2 further comprising a principal axis (6), the discharge vessel (1) further comprising end portions (7, 8) intersected by the principal axis (6) and - the electrodes (3, 4) pass the discharge vessel (1) via at least one end portion (7, 8).

4. A dielectric barrier discharge lamp according to claim 1 or 2, wherein at least a part of the electrode of the first type (3) or at least a part of the electrode of the second type (4) does have an area shape (13, 23, 14, 24, 34).

5. A dielectric barrier discharge lamp according to claim 4, wherein at least a part of the electrode of the first type (3) or at least a part of the electrode of the second type (4) does not have cylinder symmetry with respect to the axis of symmetry of the respective part of the electrodes.

6. A dielectric barrier discharge lamp according to claim 4, wherein at least a first part (13, 23) of the electrode of the first type (3) and at least a second part (14, 24) of the electrode of the second type (4) have an area shape and the first part (13, 23) of the electrode of the first type (3) extending in the discharge volume (2) is parallel to the second part (14, 24) of the electrode of the second type (4) extending in the discharge volume (4).

7. A dielectric barrier discharge lamp according to claim 6, wherein the electrode of the first type (3) comprises a first rod and at least one first area shaped part (23), and the electrode of the second type (4) comprises a second rod and at least one second area shaped part (24) and the first area shaped part (23) and the first rod enclose an angle bigger than 45° and the second area shaped part (24) and the second rod enclose the same angle bigger than 45° as the first rod and the first area shaped part (23).

8. A dielectric barrier discharge lamp according to any one of the claims 1,

2, 5, 6, or 7 further comprising at least one stabilization structure (9) being positioned in the discharge volume (2) and the stabilization structure (9) is connected with the electrode of the first type (3) and the electrode of the second type (4).

9. A dielectric barrier discharge lamp according to claim 8 whereby at least one stabilization structure (9) is connected with the discharge vessel (1).

10. A method of manufacturing of a dielectric barrier discharge lamp, the method comprising the steps of: providing a discharge vessel (1), - enclosing a discharge volume (2) in the discharge vessel (2), providing at least one electrode of a first type (3) and at least one electrode of a second type (4), the electrode of the first type (3) being designed to act as a low voltage electrode and the electrode of the second type (4) being designed to act as high voltage electrode - positioning the electrodes (3, 4) within the discharge volume (2), at least partly insulating at least the electrode of the first type (3) or at least the electrode of the second type (4) from the discharge volume (2) by providing at least one dielectric layer (5) on the electrode of the first type (3) or the electrode of the second type (4), - suspending each electrode (3, 4) from the discharge vessel (1) by means of at least two suspensions (10) and filling the discharge volume (2) with a discharge gas.

11. A system incorporating a lamp according to any one of the claims 1 , 2, 5, 6, 7 or 9 and the system being used in the treatment of at least one chosen from the group of treatment of surfaces of solids, treatment of liquids and treatment of gases.