The invention relates to a dielectric barrier based radiation generating system. Further, the invention relates to a lamp comprising such dielectric barrier based radiation generating system. Yet further, the invention relates to a method for treating a gas or a surface with the dielectric barrier based radiation generating system or the lamp.

BACKGROUND OF THE INVENTION

Dielectric barrier discharge lamps are known in the art. US6777878, for instance, describes a dielectric barrier discharge lamp having an elongated discharge vessel defining a longitudinal axis, and having elongated dielectrically impeded electrodes arranged on the discharge vessel wall along this longitudinal axis, and having at least one electrically conductive means that extends with reference to the longitudinal axis only over a subregion of the discharge vessel wall and that is arranged on the discharge vessel wall to support the ignition of the dielectrically impeded discharge. The means is a ring or part of a ring. The means is a tightly wound filament.

SUMMARY OF THE INVENTION

UV light has been used for disinfection for over 100 years. Wavelengths between about 190 nm and 300 nm may be strongly absorbed by nucleic acids, which may result in defects in an organism’s genome. This may be desired for killing bacteria and viruses, but may also have undesired side effects for humans. Therefore the selection of wavelength of radiation, intensity of radiation and duration of irradiation may be limited in environments where people may reside such as offices, public transport, cinema’s, restaurants, shops, etc., thus limiting the disinfection capacity. Especially in such environments, additional measures of disinfection may be advantageous to prevent the spread of bacteria and viruses such as influenza or novel (corona) viruses like CO VID-19, SARS and MERS.

It appears desirable to produce systems, that provide alternative ways for air treatment, such as disinfection. Further, existing systems for disinfection may not easily be implemented in existing infrastructure, such as in existing buildings like offices, hospitality areas, etc. and/or may not easily be able to serve larger spaces. This may again increase the risk of contamination. Further, incorporation in HVAC systems may not lead to desirable effects and appears to be relatively complex. Further, existing systems may not be efficient, or may be relatively bulky, and may also not easily be incorporated in functional devices, such as e.g. luminaires. Other disinfection systems may use one or more anti-microbial and/or anti-viral means to disinfect a space or an object. Examples of such means may be chemical agents which may raise concerns. For instance, the chemical agents may also be harmful for people and pets. In embodiments, the disinfecting light, may especially comprise ultraviolet

(UV) radiation (and/or optionally violet radiation), i.e., the light may comprise a wavelength selected from the ultraviolet wavelength range (and/or optionally the violet wavelength range). However, other wavelengths are herein not excluded. The ultraviolet wavelength range is defined as light in a wavelength range from 100 to 380 nm and can be divided into different types of UV light / UV wavelength ranges (Table 1). Different UV wavelengths of radiation may have different properties and thus may have different compatibility with human presence and may have different effects when used for disinfection (Table 1).

Table 1 : Properties of different types of UV wavelength light

Each UV type / wavelength range may have different benefits and/or drawbacks. Relevant aspects may be (relative) sterilization effectiveness, safety (regarding radiation), and ozone production (as result of its radiation). Depending on an application a specific type of UV light or a specific combination of UV light types may be selected and provides superior performance over other types of UV light. UV-A may be (relatively) safe and may kill bacteria, but may be less effective in killing viruses. UV-B may be (relatively) safe when a low dose (i.e. low exposure time and/or low intensity) is used, may kill bacteria, and may be moderately effective in killing viruses. UV-B may also have the additional benefit that it can be used effectively in the production of vitamin D in a skin of a person or animal. Near UV-C may be relatively unsafe, but may effectively kill bacteria and viruses. Far UV may also be effective in killing bacteria and viruses, but may be (relatively to other UV-C wavelength ranges) (rather) safe. Far-UV light may generate some ozone which may be harmful for human beings and animals. Extreme UV-C may also be effective in killing bacteria and viruses, but may be relatively unsafe. Extreme UV-C may generate ozone which may be undesired when exposed to human beings or animals. In some application ozone may be desired and may contribute to disinfection, but then its shielding from humans and animals may be desired. Hence, in the table “+” for ozone production especially implies that ozone is produced which may be useful for disinfection applications, but may be harmful for humans / animals when they are exposed to it. Hence, in many applications this “+” may actually be undesired while in others, it may be desired.

Hence, in embodiments, the light may comprise a wavelength in the UV-A range. In further embodiments, the light may comprise a wavelength in the UV-B range. In further embodiments, the light may comprise a wavelength in the Near UV-C range. In further embodiments, the light may comprise a wavelength in the Far UV range. In further embodiments, the light may comprise a wavelength in the extreme UV-C range. The Near UV-C, the Far UV and the extreme UV-C ranges may herein also collectively be referred to as the UV-C range. Hence, in embodiments, the light may comprise a wavelength in the UV- C range. In other embodiments, the light may comprise violet radiation.

Dielectric barrier discharges are a mercury free source of UV radiation. The use of halogens like bromine and chlorine enables the generation of UV in the range of about 200-230 nm. As indicated above, this radiation can inactivate harmful viruses by destroying their DNA/RNA, and/or inactivate other parts of the virus proteins. Their wavelength is substantially long enough to prevent the generation of substantial amounts of ozone and substantially short enough not the reach the living skin cells or the cornea of humans possibly present when the UV source is operational.

The halogen in the discharge vessel may capture the few free electrons that are normally present when the UV source is off, or that can be released from residual wall charges deposited during last operation, and therefore especially after some time in the dark it might take a lot of attempts to start the discharge. A solution may be to use a quartz UV enhancer containing mercury. However, this will reintroduce mercury in the system, which may not be desirable. As an alternative, a small amount of ⁸⁵ Kr might be used to ease the ignition. However, this is a radioactive gas and will require licenses to use the radioactive gas and to transport the UV sources. Hence, also this does not seem to be a desirable solution.

Hence, it is an aspect of the invention to provide an alternative (dielectric barrier based) radiation generating system, which preferably further at least partly obviates one or more of above-described drawbacks. The present invention may have as object to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

In an aspect, the invention provides a dielectric barrier based radiation generating system comprising a dielectric barrier discharge lamp (“DBD lamp” or “DBD”), and an ignition aiding device (“ignition device”). Especially, in embodiments the dielectric barrier discharge lamp may comprise (a) a discharge vessel comprising a discharge vessel filling, (b) a first discharge lamp electrode, and (c) a second discharge lamp electrode. In embodiments, at least part of the discharge vessel may be transmissive for radiation having a first wavelength i. Especially, the dielectric barrier discharge lamp may be configured to emit during operation of the dielectric barrier discharge lamp dielectric barrier discharge lamp radiation. Further, in embodiments the ignition aiding device may comprises (i) a ceramic vessel, containing a ceramic vessel space comprising a ceramic vessel filling, (ii) a first ignition aiding device electrode, and (iii) a second ignition aiding device electrode. Especially, in embodiments the first ignition aiding electrode may extend into the ceramic vessel space. Yet further, the second ignition aiding device electrode may be configured external from the ceramic vessel. Especially, in embodiments the vessel filling may comprise a noble gas. Further, in specific embodiments the first ignition aiding device electrode may be electrically coupled to the first discharge lamp electrode. Yet further, in specific embodiments the second ignition aiding device electrode may be electrically coupled to the second discharge lamp electrode. Especially, in embodiments during at least part of the operation of the dielectric barrier based radiation generating system the ignition aiding device may be configured to emit radiation having the first wavelength i. Therefore, in embodiments the invention provides a dielectric barrier based radiation generating system comprising a dielectric barrier discharge lamp and an ignition aiding device, wherein: (A) the dielectric barrier discharge lamp comprises (a) a discharge vessel comprising a discharge vessel filling, (b) a first discharge lamp electrode, and (c) a second discharge lamp electrode; wherein at least part of the discharge vessel is transmissive for radiation having a first wavelength i; wherein the dielectric barrier discharge lamp is configured to emit during operation of the dielectric barrier discharge lamp dielectric barrier discharge lamp radiation; (B) the ignition aiding device comprises (i) a ceramic vessel, containing a ceramic vessel space comprising a ceramic vessel filling, (ii) a first ignition aiding device electrode, and (iii) a second ignition aiding device electrode; wherein the first ignition aiding electrode extends into the ceramic vessel space, and wherein the second ignition aiding device electrode is configured external from the ceramic vessel, wherein the ceramic vessel filling comprises a noble gas; and (C) the first ignition aiding device electrode is electrically coupled to the first discharge lamp electrode; the second ignition aiding device electrode is electrically coupled to the second discharge lamp electrode; and wherein during at least part of the operation of the dielectric barrier based radiation generating system the ignition aiding device is configured to emit radiation having the first wavelength i.

In yet an aspect, the invention provides a dielectric barrier based radiation generating system comprising a dielectric barrier discharge lamp (“DBD lamp” or “DBD”), an ignition aiding device (“ignition device”), and a control system. In embodiments, the dielectric barrier discharge lamp may comprise (a) a discharge vessel comprising a discharge vessel filling, (b) a first discharge lamp electrode, and (c) a second discharge lamp electrode. Further, in embodiments at least part of the discharge vessel may be transmissive for radiation having a first wavelength i. Especially, in embodiments the dielectric barrier discharge lamp is configured to emit during operation of the dielectric barrier discharge lamp dielectric barrier discharge lamp radiation. In embodiments, the ignition aiding device may comprise (i) a ceramic vessel, containing a ceramic vessel space comprising a ceramic vessel filling, (ii) a first ignition aiding device electrode, and (iii) a second ignition aiding device electrode. Especially, in embodiments the first ignition aiding electrode may extend into the ceramic vessel space. Further, in embodiments the second ignition aiding device electrode may be configured external from the ceramic vessel. Yet further, in embodiments the vessel filling may comprise a noble gas. Especially, the control system may comprises (i) a dielectric barrier discharge lamp control system functionally coupled to one or more of (i) the first discharge lamp electrode and (ii) the second discharge lamp electrode, especially to both. Further, the control system may comprises (ii) an ignition aiding device control system functionally coupled to one or more of (i) the first ignition aiding device electrode and (ii) the second ignition aiding device electrode (especially both). Especially, in embodiments the control system may be configured to control the dielectric barrier discharge lamp and (optionally) the ignition aiding device. In specific embodiments, the control system may be configured to switch off only the ignition aiding device after operation of the ignition aiding device at a predetermined minimum voltage during a predetermined minimum time or on the basis of a control signal. Yet further, in embodiments the dielectric barrier discharge lamp control system and the ignition aiding device control system may comprise drivers. Hence, especially in embodiments the invention provides a dielectric barrier based radiation generating system comprising a dielectric barrier discharge lamp, an ignition aiding device, and a control system, wherein: (A) the dielectric barrier discharge lamp comprises (a) a discharge vessel comprising a discharge vessel filling, (b) a first discharge lamp electrode, and (c) a second discharge lamp electrode; wherein at least part of the discharge vessel is transmissive for radiation having a first wavelength i; wherein the dielectric barrier discharge lamp is configured to emit during operation of the dielectric barrier discharge lamp dielectric barrier discharge lamp radiation; (B) the ignition aiding device comprises (i) a ceramic vessel, containing a ceramic vessel space comprising a ceramic vessel filling, (ii) a first ignition aiding device electrode, and (iii) a second ignition aiding device electrode; wherein the first ignition aiding electrode extends into the ceramic vessel space, and wherein the second ignition aiding device electrode is configured external from the ceramic vessel, wherein the ceramic vessel filling comprises a noble gas; and (C) the control system comprises (i) a dielectric barrier discharge lamp control system functionally coupled to one or more of (i) the first discharge lamp electrode and (ii) the second discharge lamp electrode, and (ii) an ignition aiding device control system functionally coupled to one or more of (i) the first ignition aiding device electrode and (ii) the second ignition aiding device electrode; wherein the control system is configured to control the dielectric barrier discharge lamp and the ignition aiding device, wherein the control system is configured to switch off the ignition aiding device after operation of the ignition aiding device at a predetermined minimum voltage during a predetermined minimum time or on the basis of a control signal, and wherein the dielectric barrier discharge lamp control system and the ignition aiding device control system comprise drivers.

With such system(s), for its operation it does not need a separate electronic circuit to drive the enhancer. However, in specific aspects, such separate electronic circuit is not excluded (see also below). Further, it appears that the ignition aiding device may provide a lot of UV at the right moment in the ignition cycle. Yet further, the ignition aiding device can operate on the same power source as the DBD (“dielectric barrier discharge”). Hence, the starting time can be much shorter with the ignition aiding device. In specific aspects, however, a driver may be used. Such driver, or other solutions described herein, may also allow to switch off the ignition aiding device after the DBD lamp is (properly) operating.

Dielectric barrier based radiation lamps are known in the art, and are for instance described in US2010/0164410; U. Kogelschatz, Dielectric-Barrier Discharges: Their History, Discharge Physics, and Industrial Applications. Plasma Chemistry and Plasma Processing 23, 1-46, https://doi.Org/10.1023/A: 1022470901385; WO 2006/006139; and R. Brandenburg, Dielectric barrier discharges: progress on plasma sources and on the understanding of regimes and single fdaments, Plasma Sources Science and Technology, Vol. 26, No. 5, 1-29, including corrigendum, which four disclosures are herein incorporated by reference. Especially, dielectric-barrier discharge (DBD) is the electrical discharge between two electrodes separated by an insulating dielectric barrier. DBD devices can be made in many configurations, typically planar, using parallel plates separated by a dielectric or cylindrical, using coaxial plates with a dielectric tube between them.

The basic principle of these lamps may be the generation and emission of radiation by means of a dielectric barrier discharge. Usually, at least one of the two electrodes of such a lamp is located outside the discharge volume. The discharge volume comprises a discharge gas, especially at or around the lamp envelope, wherein the energy supply is accomplished by capacitive coupling through the walls of the lamp envelope into the discharge volume, in order to initiate within this volume the gas discharge and the excitation and emission of radiation. Generally, such dielectric barrier discharge lamps may be used as an alternative to conventional mercury based discharge lamps in a wide area of applications, where a radiation of a certain wavelength has to be generated for a variety of purposes. Some applications are for example the generation of ultraviolet (UV) radiation with wavelengths oaf between about 170 nm and about 380 nm for industrial purposes such as waste water treatment, disinfection of gases and fluids, especially of drinking water, dichlorination or production of ultra-pure water, activation and cleaning of surfaces, curing of lacquers, inks or paints, ozone generation, or for liquid crystal display (LCD) backlighting or photocopiers and others. Furthermore, dielectric barrier discharge lamps are of increasing importance especially as a source for generating and/or emitting high intensity and high power ultraviolet (UV) radiation in a narrow and well defined spectral range with high efficiency and high radiation intensity. WO 2006/006139, for instance, describes a dielectric barrier discharge lamp comprising a discharge gap being at least partly formed and/or surrounded by at least an inner wall and an outer wall, wherein at least one of the walls is a dielectric wall and at least one of the walls has an at least partly transparent part, a filling located inside the discharge gap, at least a first electrical contacting means for contacting the outer wall and a second electrical contacting means for contacting the inner wall, and at least one multifunctional means which is arranged adjacent to the discharge gap and which on the one hand serves as an improved and optimized ignition aid, especially for initial ignition or ignition after a long pause, and on the other hand serves at least as guiding means for easily arranging two walls towards each other, thereby forming an optimized discharge gap especially for coaxial dielectric barrier discharge lamps. In embodiments, the dielectric barrier discharge lamp may comprise a discharge volume which is delimited by a first and a second wall, wherein (during operation) both walls are exposed to different electrical potentials by means of a power supply for exciting a gas discharge within the discharge volume.

As indicated above, the invention provides a dielectric barrier based radiation generating system comprising a dielectric barrier discharge lamp and an ignition aiding device. Hence, the system may comprise two devices, which may be integrated in a single device. The system may be comprised by a housing. The dielectric barrier discharge lamp may comprise (a) a discharge vessel comprising a discharge vessel filling, (b) a first discharge lamp electrode, and (c) a second discharge lamp electrode. Especially, the electrodes may in embodiments be external from the vessel (and do not extend into the discharge vessel and/or have not contact with the discharge vessel filling). The discharge vessel may especially defined a discharge vessel space. The discharge vessel space may contain the discharge vessel filling.

During operation of the DBD lamp, radiation (“dielectric barrier discharge lamp radiation”) is generated, which may escape from the discharge vessel. Especially, at least part of the discharge vessel may be transmissive for radiation having one or more wavelengths selected from the range of 180-250 nm, such as 190-240 nm, such as in specific embodiments 200-230 nm. Especially, in embodiments the dielectric barrier discharge lamp may be configured to emit dielectric barrier discharge lamp radiation having a wavelength selected from the range of 180-250 nm, such as 190-240 nm, such as in specific embodiments 200-230 nm. Therefore, at least part of the discharge vessel may be transmissive for one or more wavelength selected from the respective wavelength range. In this way, the dielectric discharge lamp may be configured to emit during operation of the dielectric barrier discharge lamp dielectric barrier discharge lamp radiation (which may especially be in the UV).

Further, the discharge vessel may be transmissive for radiation generated by the ignition aid. Hence, especially at least part of the discharge vessel is transmissive for radiation having a first wavelength i. The phrase “transmissive for radiation having a first wavelength i” may also indicated that the discharge vessel is transmissive for a plurality of (first) wavelengths. The first wavelength refers to radiation generated by the ignition aid, which should penetrate into the discharge vessel. In specific embodiments, the first wavelength i may be selected from the range of 250-400 nm. Hence, at least part of the discharge vessel may be transmissive for one or more (first) wavelengths selected from the range of 250-400 nm (see further also below).

The discharge vessel may contain a discharge vessel filling. Hence, the discharge vessel filling may especially be enclosed by the discharge vessel. The term “discharge vessel filling” may especially indicate a filling contained by the discharge vessel. The discharge vessel filling may especially comprise a gas. The discharge vessel filling may especially comprise one or more of a halogen and a noble gas. In embodiments, the discharge vessel filling may comprise one or more of chlorine and bromine, and/or one or more of krypton and neon. In specific embodiments, the discharge vessel filling may comprise in embodiments mixtures of krypton, bromine and one or more other noble gases and in other embodiments may comprise mixtures of krypton, chlorine, bromine and one or more other noble gases. Hence, in embodiments discharge vessel filling may comprise Kr and Ne, and one or more of Cl and Br.

As indicated above, an ignition aiding device may be used. During operation, the ignition aiding device may be configured to emit radiation having the first wavelength i. Also the ignition aiding device comprises a vessel (especially a ceramic vessel). Hence, especially at least part of this vessel is transmissive for the radiation having the first wavelength. As indicated above, one or more (first) wavelengths (of the radiation generated by the ignition aiding device) may be selected from the range of 250-400 nm. In embodiments, due to the presence of argon in the gas phase and/or erbium in the wall material (see also below) emission(s) may also be found in the range of 680-850 nm.

Here, the term “transmissive” especially refers to optically transmissive. In general, the transmissive of the indicated radiation may be at least 40%, such as at least 50%, like at least 60% under perpendicular irradiation of the discharge vessel with the indicated radiation. Higher transmissions, like at least 70% may also be possible. For instance, PCA may have a transmission of at least 60%, or even at least about 70% down to about 250 nm. As will also further be elucidated below, the ceramic vessel is also transmissive for radiation; during its operation it may generate radiation having the first wavelength, of which at least part may be transmitted by the (ceramic) vessel.

Especially, the discharge vessel of the DBD lamp may be configured in a radiation receiving relationship with the vessel of the ignition aiding device. Hence, during operation of the ignition aiding device, at least part of the emitted radiation (from the ignition aiding device) may irradiate the discharge vessel of the DBD lamp. In this way, the start of the DBD may be facilitated. Hence, the ignition aiding device and the discharge vessel may be radiationally coupled.

The terms "radiationally coupled" or “optically coupled” may especially mean that (i) a light generating element, such as a light source, and (ii) another item or material, are associated with each other so that at least part of the radiation emitted by the light generating element is received by the item or material. In other words, the item or material is configured in a light-receiving relationship with the light generating element. At least part of the radiation of the light generating element will be received by the item or material. This may in embodiments be directly, such as the item or material in physical contact with the (light emitting surface of the) light generating element. This may in embodiments be via a medium, like air, a gas, or a liquid or solid light guiding material. In embodiments, also one or more optics, like a lens, a reflector, an optical filter, may be configured in the optical path between light generating element and item or material. The term “in a light-receiving relationship” does, as indicated above, not exclude the presence of intermediate optical elements, such as lenses, collimators, reflectors, dichroic mirrors, etc. In embodiments, the term “lightreceiving relationship” and “downstream” may essentially be synonyms.

The terms “upstream” and “downstream” relate to an arrangement of items or features relative to the propagation of the light from a light generating means (here the especially the light source), wherein relative to a first position within a beam of light from the light generating means, a second position in the beam of light closer to the light generating means is “upstream”, and a third position within the beam of light further away from the light generating means is “downstream”.

Especially, in embodiments the ignition aiding device may comprise (i) a ceramic vessel, containing a ceramic vessel space comprising a ceramic vessel filling, (ii) a first ignition aiding device electrode, and (iii) a second ignition aiding device electrode. As indicated above, during operation the ignition aiding device may be configured to emit radiation having the first wavelength i. Especially, in embodiments the first ignition aiding electrode extends into the ceramic vessel space. Especially, in embodiments the second ignition aiding device electrode is configured external from the ceramic vessel (and does thus not extends into the ceramic vessel space).

In embodiments, the first ignition aiding electrode may have a diameter selected from the range of 0.5-1 mm, though other diameters may be possible. The ceramic vessel space may have an (internal) diameter of about 0.5-2 mm, such as in the range of 0.5-1 mm. Especially, the (internal) diameter of the ceramic vessel space is larger than of the first ignition aiding electrode. For instance, in embodiments the diameter is at least 0.02 mm, such as at least about 0.04 mm larger, such as up to about 0.1 mm larger. However, other values may also be possible. The outer diameter of the ceramic vessel may be about 1.5-3 mm, such as in the range of about 1.8-2.2 mm. The length of the ceramic vessel space may e.g. be in the range of about 1-20 mm, such as in the range of about 1.5-15 mm. The total length of the ceramic vessel may e.g. be in the range of about 2-20 mm. However, other dimensions than indicated herein may also be possible.

Especially, the ceramic vessel filling comprises a noble gas. Especially, in embodiments the ceramic vessel filling comprises argon. In embodiments, argon may be available up to about 300 mbar (at RT). In other embodiments, the ceramic vessel filling comprises Ne. In yet other embodiments, the ceramic vessel filling comprises Ne and Ar. Yet further, in specific embodiments the ceramic vessel filling comprises less than about 10,000 ppm other gasses (other than argon or other than argon and neon), such as up to about 5,000 ppm, like at maximum about 2,000 ppm.

In specific embodiments, the ceramic vessel comprises AI2O3 ceramic material. However, other materials, like of the YAG type (such as Y3AI5O12), may also be possible. Especially, in embodiments the (AI2O3) ceramic material may comprise one or more of MgO and EnCh. Especially, at least the latter may be desirable. Hence, in embodiments the (AI2O3) ceramic material may comprise one or more of MgO and EnCh. Especially, the ceramic material may comprise erbium ions. Hence, in embodiments the AI2O3 ceramic material (or other ceramic material) may be doped with Er ³⁺ .

In specific embodiments, the first ignition aiding device electrode comprises a niobium electrode. However, other materials may also be possible, including alloys (see also below). In specific embodiments, the second ignition aiding device electrode may comprise a molybdenum electrode. However, other materials may also be possible, including alloys (see also below). In further specific embodiments, the second ignition aiding device electrode may comprise a molybdenum wire.

In specific embodiments, the second ignition aiding device electrode comprises one or more coils enclosing the ceramic vessel. For instance, in embodiments in the range of 1-10, like 2-5, coils (or “windings”) may be around the ceramic vessel. As can be derived from the above, the second ignition aiding device electrode may comprise a molybdenum wire of which part is coiled, to provide the one or more coils enclosing the ceramic vessel. Hence, the ceramic vessel may especially be tubular. The second ignition aiding device electrode may enclose a part of the total external (tubular) external surface of the ceramic vessel, and leave a part free for escape of radiation from the ceramic vessel during operation of the ignition aiding device. For instance, less than 25% of the total external (tubular) external surface of the ceramic vessel may be blocked by the second ignition aiding device electrode. In embodiments, the UV-enhancer as described in US2014/0320001, incorporated herein by reference, may be applied. Some specific embodiments of the ignition aiding device are described below. In embodiments, the ignition aiding device may have a wall enclosing an electrode space with a filling gas and an internal electrode extending from the electrode space through the wall. Especially, the wall of the ignition aiding device may be made of ceramic material. In embodiments, the electrode may be directly sealed into the ceramic wall. The ceramic vessel filling may comprise a noble gas, i.e. at least one of helium, neon, argon, xenon, and krypton (especially with the avoidance of radioactive ⁸⁵ Kr). Especially, the noble gas may comprise one or more of neon, argon or xenon.

A technique to realize direct seals is via shrink sealing. The ignition aiding device especially have a wall of densely sintered polycrystalline aluminum oxide. This material is often used in the manufacture of high-pressure discharge lamps, so that an existing technology for ceramic discharge vessels can be employed, allowing miniaturization within strict tolerance limits.

For the ignition aiding device, the electrode may be sealed into the wall by means of a sealing glass, requiring extra steps in the manufacturing process of the ignition aiding device. This process can be performed under a (chosen) gas atmosphere, which may be around the fill pressure needed to operate the device, such as in embodiments at about 50- 300 millibar or about 5000-30000 Pascal.

A direct sealing of an (Nb) electrode in the wall may have to be performed under vacuum or circumstances proximate to vacuum to avoid detrimental effects on the translucency of the ceramic wall and hence possibly on the UV-output, and/or to avoid detrimental effect on the seal for example to prevent reaction of Nb with gas, such as with hydrogen. However, it also appears that a direct sealing under gas atmosphere is possible without detrimental effects on the seal and without meaningful detrimental effects on the ignition aiding / UV-enhancing properties of the ignition aiding device. Various methods can be followed to obtain the direct seal.

A first method comprises the two steps of: pre-sealing of the electrode, which can either be a metal tube, rod, foil or wire, under a H2-atmosphere at about 1450-1600° C. Without being held to theoretical considerations, it is thus thought that a not yet gastight preseal between wall of the ignition aiding device and electrode is obtained as the sintered ceramic wall material as such is already gastight; final-sealing of the electrode under a filling gas-atmosphere, for example argon, at a desired gas pressure and at a temperature of about 1850° C, such that after cooling down the desired filling gas pressure is present in the electrode space of the ignition aiding device when a rod, wire of foil is used as electrode. Alternatively, when a tube is used, the gas pressure is easily set to the desire pressure after the sealing and subsequently the tube is closed by means of a metal drop formed by melting an end of the tube with a laser. Without being held to theoretical considerations it is thought that exchange of the gas in the electrode space from H2 to filling gas occurs via a not yet completely sealed interface between wall of the ignition aiding device and the electrode surface due to the rough surface of the electrode. Since in the first process step the PCA (polycrystalline aluminum oxide) was already sintered to a certain degree of closed porosity it subsequently is sintered to full density in the second process step.

A second, relatively fast, flexible and cheap method comprises only one step, i.e. direct sealing at about 1850 °C of the electrode in the wall of the ignition aiding device under a rare gas atmosphere at desired gas pressure, such that after cooling down the desired filling gas pressure is present in the electrode space of the UV-enhancer when a rod, wire of foil is used as electrode. Alternatively, when a tube is used, the gas pressure is easily set to the desire pressure after the sealing and subsequently the tube is closed by means of a metal drop formed by melting an end of the tube with a laser. Without being held to theoretical considerations it is thought that the following occurs: At the start of both these methods the ceramic material of the wall has an open porous structure enabling the pores in the structure to be filled with the gas used at the start of both the methods. In the first method, the first process step is sintering at about 1500° C and a first shrinkage of the fully open porous structure occurs, enough for the wall material to shrink tightly around the electrode and thus to directly embed the electrode in the ceramic wall. However, said first shrinkage is not enough to fully close the open porous structure. Hence, in the second process step of the first method a change of gas atmosphere is done and subsequently a second further sintering and some shrinkage at about 1850 °C occurs. Due to the still somewhat open structure at the beginning of said second process step, at least to a large extent an exchange of the gases from the first process gas (H2) to the second process gas (filling gas, for example xenon or argon) occurs in the pores of the ceramic material and is enclosed in the ceramic material of the wall as gas inclusions, in particular adjacent the interface between ceramic wall material and electrode. In the second method, the gas used at the start of the process is the filling gas and at a process temperature of about 1850 °C full shrinkage occurs in one step during which said filling gas is enclosed throughout and homogeneously in the ceramic material of the wall.

The first and second method both have the advantage over the prior art that the cumbersome or expensive manufacture steps under vacuum, required for direct sealing and as used in the prior art processes, are avoided. Both inventive processes have the characteristic effect that the filling gas, such as argon gas is captured or enclosed in the remaining pores of the ceramic material of the wall and/or adjacent the interface of ceramic wall and electrode, or in other words that filling gas inclusions are present in the ceramic wall. The first method has the advantage that the translucency of the ceramic material, for example PC A, of the wall of the ignition aiding device is relatively high, while in the second method the translucency of the PC A wall is somewhat reduced compared to the translucency of the wall of the ignition aiding device obtained via the first method. Yet the translucency of the ignition aiding device wall obtained by the second method still is adequate to enable the ignition aiding device to serve its purpose. Both the methods have the advantage that the extra step of closing of the electrode tube, for example by a laser or arc melting, is avoidable, thus rendering the advantage that the use of electrode rods, wires and foils is enabled. Furthermore said methods are faster and cheaper methods compared to the prior art methods using a sealing glass. On the other hand, laser closing enables easily setting of the desired gas pressure inside the electrode space of the ignition aiding device. The second method has the advantage over the first method that it is simpler, faster and cheaper than the first method. Direct sealing further has the advantage that the necessary creepage distance in a lamp, to counteract flashover between the ignition aiding device and the discharge vessel, may be shorter as with ignition aiding device using a sealing glass. This is especially advantageous in gas filled lamps. Generally the sealing glass is electrically conductive, leading to shorter creepage distances. Hence, lamps with a directly ignition aiding device enable a position of the ignition aiding device closer to the discharge vessel than in the known prior art lamps and hence a more compact lamp is obtainable.

In specific embodiments, the electrode may be made from a metal or metal alloy, the metal being chosen from the group consisting of Niobium, Molybdenum, Tungsten, Iridium, Ruthenium and Rhenium. These metals have suitable chemical and physical properties, i.e. a relatively good oxidation resistance at elevated temperatures and a coefficient of thermal expansion matching with the coefficient of thermal expansion of PC A, to function correctly under the lamp circumstances during lifetime of the lamp. Nb has a coefficient of thermal expansion that matches very well with the coefficient of thermal expansion of PC A, however, Nb is relatively sensitive to oxidation. Mo, W and Re have a better resistance to oxidation than Nb, but the match in thermal expansion with PCA is worse than for Nb. Ir has both a good match in thermal expansion with PCA and has an excellent oxidation resistance, but is expensive. In other embodiments, the electrode is made from a mixture of metal or metal alloy and a ceramic material (cermet), the metal being chosen from the group consisting of Niobium, Molybdenum, Tungsten, Ruthenium, Iridium and Rhenium. Further, in embodiments the ceramic material may be chosen from the group AI2O3, Y2O3, Y3AI5O12, ZrCh, MgO, MgAL2O4, B2O3 and mixtures thereof. Cermets are composite materials made of both ceramic and metallic components especially suitable for use in lighting applications.

In specific embodiments, the ignition aiding device has a wall of densely sintered yttrium aluminum garnet (YAG), or polycrystalline aluminum oxide (PCA), or has a wall from PCA doped with MgO, MgO — EnCE or MgO — EnCE — ZrO2 as this material seems to result in a favorable lower flash-over voltage for ignition of the lamp than in the case when undoped PCA is used.

In specific embodiments, the enhancer electrode has a lead-through at a first extremity of the ignition aiding device, the extremity of the enhancer electrode within the ignition aiding device is spaced apart from the first extremity of the ignition aiding device by a distance which is at least equal to twice the external diameter of the ignition aiding device. In such a construction, the possibility of an unwanted breakdown between the metal curl and the lead-through to the enhancer electrode is very small when ignition pulses are supplied.

In embodiments, a combination of mercury and a rare gas is possible as a filling for the ignition aiding device. However, a rare gas or a mixture of rare gases is preferred, because this precludes the use of the heavy metal mercury. Especially, in embodiments argon may be used as a filling for the ignition aiding device. At about room temperature, the filling pressure of the rare gas filling may in embodiments preferably chosen to be in the range from 50 to 300 mbar. At pressure values of less than 50 mbar, the UV output of the enhancer appears to become smaller; at pressure values of more than 300 mbar, the ignition voltage of the enhancer may assume too high values.

In embodiments, the first ignition aiding device electrode may be electrically coupled to the first discharge lamp electrode and/or the second ignition aiding device electrode may be electrically coupled to the second discharge lamp electrode. In this way, the ignition aiding device may be coupled to the discharge lamp. When the latter is switched on, the former may also be switched on, and may immediately aid in getting the discharge lamp started. In this way, during at least part of the operation of the dielectric barrier based radiation generating system the ignition aiding device is configured to emit radiation having the first wavelength i. At least part of this radiation enters the discharge vessel. Especially, in embodiments the dielectric barrier discharge lamp is configured to emit dielectric barrier discharge lamp radiation when the first discharge lamp electrode and the second discharge lamp electrode are subjected to a pulsed first potential difference AVi. Further, in embodiments the ignition aiding device may be configured to emit radiation having the first wavelength i when the first ignition aiding device electrode, and the second ignition aiding device electrode are subjected to a predetermined second potential difference AV2. Especially, in embodiments AVi is at least 0.5 kV, even more especially at least about 1 kV. Especially, in embodiments when the electrodes of the dielectric barrier discharge lamp and the electrodes of the ignition aiding device are coupled as above, the dielectric barrier discharge lamp and the ignition aiding device may be subjected, during operation, to essentially the same potential differences. In specific embodiments, AVi= AV2, and AVi is at least 1 kV.

In specific embodiments, the first discharge lamp electrode is a grounded electrode. Hence, in specific embodiments the first ignition aiding device electrode may also be a grounded electrode.

In further specific embodiments, the dielectric barrier based radiation generating system may further comprise a control system, configured to control the dielectric barrier discharge lamp. Especially, the control system may comprise a driver. The driver may be configured to drive the dielectric barrier discharge lamp.

It may be desirable to switch off the ignition aiding device after the dielectric barrier discharge lamp has started. This may increase the lifetime of the ignition aiding device. To this end, the dielectric barrier based radiation generating system may in embodiments comprise an ignition aiding device control system configured to switch off the ignition aiding device when the dielectric barrier discharge lamp has started. Several options may be chosen. In embodiments, an electronic circuit may be introduced, which may switch off only the ignition aiding device electric circuit (but not the dielectric barrier discharge lamp electrical circuit). In other embodiments, a control system may be used. A specific option of former may be a relay, especially a physical relay. As known in the art, a relay is an electrically operated switch. The relay may be a high voltage relay.

Therefore, in specific embodiments the dielectric barrier based radiation generating system may further comprise an ignition aiding device control system configured to switch off only the ignition aiding device (a) after operation of the ignition aiding device at a predetermined minimum voltage during a predetermined minimum time or (b) on the basis of a control signal (or both may be used as input). As indicated above, ignition aiding device control system may thus be a relay. For instance, the relay may be configured to switch off the electric circuit related to the ignition aiding device when the predetermined minimum voltage, such as at least 0.5 kV, even more especially at least about 1 kV has been applied for a time period selected from the range of 5-500 seconds, such as 5-60 seconds.

The control signal may in embodiments be provided by e.g. a sensor. The sensor may be configured to sense the dielectric barrier discharge lamp radiation. The sensor may be configured to sense e.g. DBD emission lines (e.g. emissions from the discharge vessel, which may e.g. be one or more of KrCl* emission, KrBr* emission, Kr lines, Ne lines) (or other emissions). In embodiments, a control system may, on the basis of the sensor signal of the sensor, define that the dielectric barrier based is operating as desired (i.e. especially started). If so, the control system may switch off the electric circuit related to the ignition aiding device. The control system may be comprised by the ignition aiding device control system, or another control system.

Alternatively or additionally, a control system may control the operation of the dielectric barrier discharge lamp. When the dielectric barrier discharge lamp is operating as desired, the current (shape) through and/or voltage over the dielectric barrier discharge lamp may have changed from what it was just before the lamp was ignited. In embodiments, an analysis of the shape, of e.g. the current, may reveal that the lamp is operating. When the control system defines that the dielectric barrier discharge lamp is operating as desired, the control system may switch off the electric circuit related to the ignition aiding device. The control system may be comprised by the ignition aiding device control system, and/or another control system (such as a dielectric barrier discharge lamp control system; see below).

As indicated above, another option to control the ignition aiding device may (thus) be to use a control system. The control system may control the ignition aiding device and the dielectric barrier based radiation generating system. For instance, both may be driven by separate drivers. In this way, when the dielectric barrier based lamp has started, or has e.g. operated for a predetermined time, or when the intensity of the dielectric barrier discharge lamp radiation is above a certain threshold, the driver for the ignition aiding device may be switched off or may be set in a sleeping mode. At least, the high voltage to the ignition aiding device may substantially be reduced.

For instance, in embodiments the control system may comprise (i) a dielectric barrier discharge lamp control system functionally coupled to one or more of (i) the first discharge lamp electrode and (ii) the second discharge lamp electrode, and (ii) an ignition aiding device control system functionally coupled to one or more of (i) the first ignition aiding device electrode and (ii) the second ignition aiding device electrode. Especially, the control system may (thus) be configured to control the dielectric barrier discharge lamp and the ignition aiding device. In specific embodiments, the control system may be configured to switch off the ignition aiding device after operation of the ignition aiding device at a predetermined minimum voltage during a predetermined minimum time or on the basis of a control signal (see also above). Further, the dielectric barrier discharge lamp control system and the ignition aiding device control system may comprise drivers.

Hence, as indicated above in an aspect the invention provides a dielectric barrier based radiation generating system comprising a dielectric barrier discharge lamp, an ignition aiding device, and a control system. The dielectric barrier discharge lamp comprises (a) a discharge vessel comprising a discharge vessel filling, (b) a first discharge lamp electrode, and (c) a second discharge lamp electrode. Especially, at least part of the discharge vessel is transmissive for radiation having a first wavelength i. Further, especially the dielectric barrier discharge lamp is configured to emit during operation of the dielectric barrier discharge lamp dielectric barrier discharge lamp radiation. In embodiments, the ignition aiding device comprises (i) a ceramic vessel, containing a ceramic vessel space comprising a ceramic vessel filling, (ii) a first ignition aiding device electrode, and (iii) a second ignition aiding device electrode. Especially, the first ignition aiding electrode extends into the ceramic vessel space. Further, in embodiments the second ignition aiding device electrode may be configured external from the ceramic vessel, wherein the ceramic vessel filling comprises a noble gas. Especially, in embodiments the control system may comprise (i) a dielectric barrier discharge lamp control system functionally coupled to one or more of (i) the first discharge lamp electrode and (ii) the second discharge lamp electrode, and (ii) an ignition aiding device control system functionally coupled to one or more of (i) the first ignition aiding device electrode and (ii) the second ignition aiding device electrode. In embodiments, the control system may be configured to control the dielectric barrier discharge lamp and the ignition aiding device. Further, especially the control system may be configured to switch off the ignition aiding device after operation of the ignition aiding device at a predetermined minimum voltage during a predetermined minimum time or on the basis of a control signal. In specific embodiments, the dielectric barrier discharge lamp control system and the ignition aiding device control system comprise drivers.

The term “controlling” and similar terms especially refer at least to determining the behavior or supervising the running of an element. Hence, herein “controlling” and similar terms may e.g. refer to imposing behavior to the element (determining the behavior or supervising the running of an element), etc., such as e.g. measuring, displaying, actuating, opening, shifting, changing temperature, etc.. Beyond that, the term “controlling” and similar terms may additionally include monitoring. Hence, the term “controlling” and similar terms may include imposing behavior on an element and also imposing behavior on an element and monitoring the element. The controlling of the element can be done with a control system, which may also be indicated as “controller”. The control system and the element may thus at least temporarily, or permanently, functionally be coupled. The element may comprise the control system. In embodiments, the control system and element may not be physically coupled. Control can be done via wired and/or wireless control. The term “control system” may also refer to a plurality of different control systems, which especially are functionally coupled, and of which e.g. one control system may be a master control system and one or more others may be slave control systems. A control system may comprise or may be functionally coupled to a user interface.

The control system may also be configured to receive and execute instructions form a remote control. In embodiments, the control system may be controlled via an App on a device, such as a portable device, like a Smartphone or I-phone, a tablet, etc.. The device is thus not necessarily coupled to the lighting system, but may be (temporarily) functionally coupled to the lighting system.

Hence, in embodiments the control system may (also) be configured to be controlled by an App on a remote device. In such embodiments the control system of the lighting system may be a slave control system or control in a slave mode. For instance, the lighting system may be identifiable with a code, especially a unique code for the respective lighting system. The control system of the lighting system may be configured to be controlled by an external control system which has access to the lighting system on the basis of knowledge (input by a user interface of with an optical sensor (e.g. QR code reader) of the (unique) code. The lighting system may also comprise means for communicating with other systems or devices, such as on the basis of Bluetooth, WIFI, LiFi, ZigBee, BLE or WiMAX, or another wireless technology.

The system, or apparatus, or device may execute an action in a “mode” or “operation mode” or “mode of operation” or “operational mode”. Likewise, in a method an action or stage, or step may be executed in a “mode” or “operation mode” or “mode of operation” or “operational mode”. This does not exclude that the system, or apparatus, or device may also be adapted for providing another controlling mode, or a plurality of other controlling modes. Likewise, this may not exclude that before executing the mode and/or after executing the mode one or more other modes may be executed.

However, in embodiments a control system may be available, that is adapted to provide at least the controlling mode. Would other modes be available, the choice of such modes may especially be executed via a user interface, though other options, like executing a mode in dependence of a sensor signal or a (time) scheme, may also be possible. The operation mode may in embodiments also refer to a system, or apparatus, or device, that can only operate in a single operation mode (i.e. “on”, without further tunability).

Hence, in embodiments, the control system may control in dependence of one or more of an input signal of a user interface, a sensor signal (of a sensor), and a timer. The term “timer” may refer to a clock and/or a predetermined time scheme.

The dielectric barrier based radiation generating system may be part of or may be applied in e.g. office lighting systems, household application systems, shop lighting systems, home lighting systems, accent lighting systems, spot lighting systems, theater lighting systems, fiber-optics application systems, projection systems, self-lit display systems, pixelated display systems, segmented display systems, warning sign systems, medical lighting application systems, indicator sign systems, decorative lighting systems, portable systems, automotive applications, (outdoor) road lighting systems, urban lighting systems, green house lighting systems, horticulture lighting, digital projection, or LCD backlighting. The dielectric barrier based radiation generating system (or luminaire) may be part of or may be applied in e.g. optical communication systems or disinfection systems.

In yet a further aspect, the invention also provides a lamp or a luminaire comprising the dielectric barrier based radiation generating system as defined herein. The luminaire may further comprise a housing, optical elements, louvres, etc. etc... The lamp or luminaire may further comprise a housing enclosing the dielectric barrier based radiation generating system. The lamp or luminaire may comprise a light window in the housing or a housing opening, through which the system light may escape from the housing. In yet a further aspect, the invention also provides a projection device comprising the dielectric barrier based radiation generating system as defined herein. Especially, a projection device or “projector” or “image projector” may be an optical device that projects an image (or moving images) onto a surface, such as e.g. a projection screen. The projection device may include one or more dielectric barrier based radiation generating systems such as described herein. Hence, in an aspect the invention also provides a light generating device selected from the group of a lamp, a luminaire, a projector device, a disinfection device, and an optical wireless communication device, comprising the dielectric barrier based radiation generating system as defined herein.

Hence, especially the invention provides in a further aspect a lamp comprising the dielectric barrier based radiation generating system as defined herein, wherein the lamp is configured to emit (lamp) radiation, wherein the (lamp) radiation comprises dielectric barrier discharge lamp radiation. Hence, in embodiments the (lamp) radiation is UV radiation. In specific embodiments, the dielectric barrier based radiation generating system may have a design selected from an axial design, a coaxial design, or a plate-like design.

In yet a further aspect, the invention provides a method for treating a gas or a surface, the method comprising providing dielectric barrier discharge lamp radiation to the gas or the surface with the dielectric barrier based radiation generating system as defined herein or the lamp as defined herein. In embodiments, the method may comprise exposing air to the radiation from the system. Hence, in specific embodiments, the method for treating air may comprise exposing air the radiation from the system. In this way, the method may provide one or more of disinfection of pathogens, removal of particles and dust, and removal of odors. Especially, the treatment of the air may comprise disinfection of (the) air. In embodiments, the method may comprise exposing a surface to the radiation from the system. The surface may be selected from a desk, a floor, a wall, a kitchen counter, a door handle, a tap, a handrail, a control panel, etc. The embodiments described above in relation to the system of the present invention, may also apply for the method of the invention.

The method may be executed in dependence of a sensor signal of a sensor. Also the dielectric barrier based radiation generating system may be operated in dependence of a sensor signal of a sensor. In embodiments, the sensor may comprise one or more sensors selected from the group comprising: a movement sensor, a presence sensor, a distance sensor, an ion sensor, a gas sensor, a volatile organic compound sensor, a pathogen sensor, an airflow sensor, a sound sensor, and a communication receiver. The ion sensor may comprise a positive ion sensor. Additionally or alternatively, the ion sensor may comprise a negative ion sensor. The pathogen sensor may comprise a sensor for one or more of bacteria, viruses, and spores. Alternatively or additionally, the sensor may comprise a temperature sensor. Further, alternatively or additionally, the sensor may comprise a humidity sensor.

The terms “light” and “radiation” are herein interchangeably used, unless clear from the context that the term “light” only refers to visible light. The terms “light” and “radiation” may thus refer to UV radiation, visible light, and IR radiation. In specific embodiments, especially for lighting applications, the terms “light” and “radiation” refer to visible light. The term UV radiation may in specific embodiments refer to near UV radiation (NUV). Therefore, herein also the term “(N)UV” is applied, to refer to in general UV, and in specific embodiments to NUV. The term IR radiation may in specific embodiments refer to near IR radiation (NIR). Therefore, herein also the term “(N)IR” is applied, to refer to in general IR, and in specific embodiments to NIR. Herein, the term “visible light” especially relates to light having a wavelength selected from the range of 380-780 nm. Herein, UV (ultraviolet) may especially refer to a wavelength selected from the range of 190-380 nm, though in specific embodiments other wavelengths may also be possible. Herein, IR (infrared) may especially refer to radiation having a wavelength selected from the range of 780-3000 nm, such as 780-2000 nm, e.g. a wavelength up to about 1500 nm, like a wavelength of at least 900 nm, though in specific embodiments other wavelengths may also be possible. Hence, the term IR may herein refer to one or more of near infrared (NIR (or IR- A)) and short- wavelength infrared (SWIR (or IR-B)), especially NIR.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

Figs, la-le schematically depict some embodiments; Fig. 2 schematically depicts and embodiment; and Fig. 3 schematically depict some applications. The schematic drawings are not necessarily to scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Fig. la-le schematically depict some embodiments and variations.

Fig. la schematically depicts a dielectric barrier based radiation generating system 1000 comprising a dielectric barrier discharge lamp 100 and an ignition aiding device 200. The dielectric barrier discharge lamp 100 comprises a discharge vessel 130 comprising a discharge vessel filling. Reference 135 refers to a discharge vessel space. This discharge vessel space 135 may especially be defined by the discharge vessel 130. The discharge vessel space especially contains the discharge vessel filling. The dielectric barrier discharge lamp 100 also comprises a first discharge lamp electrode 110 and a second discharge lamp electrode 120. At least part of the discharge vessel 130 is transmissive for radiation having a first wavelength i. The dielectric barrier discharge lamp 100 is configured to emit during operation of the dielectric barrier discharge lamp 100 dielectric barrier discharge lamp radiation 101.

The ignition aiding device 200 comprises a ceramic vessel 230, containing a ceramic vessel space 235 comprising a ceramic vessel filling. The ignition aiding device 200 comprises also comprises a first ignition aiding device electrode 210 and a second ignition aiding device electrode 220

The first ignition aiding electrode 210 extends into the ceramic vessel space 235. The second ignition aiding device electrode 220 is configured external from the ceramic vessel 230. The ceramic vessel filling comprises a noble gas.

The first ignition aiding device electrode 210 is electrically coupled to the first discharge lamp electrode 110. The second ignition aiding device electrode 220 is electrically coupled to the second discharge lamp electrode 120.

During at least part of the operation of the dielectric barrier based radiation generating system 1000 the ignition aiding device 200 is configured to emit radiation 201 having the first wavelength i.

Fig. la schematically depicts an axial design of the DBD lamp. The lamp 100 is shown along its length.

The first discharge lamp electrode 110 and the second discharge lamp electrode 120 may partially or fully enclose part of the discharge vessel 130.

Reference 300 refers to an (optional) control system.

Fig. la schematically also depicts a lamp or luminaire, indicated with reference 1200. Radiation escaping from the DBD lamp 100 is indicated with reference 101. The system 1000 may generate system light 1001, which may comprise, or essentially consist of the radiation 101. In alternative embodiments, at least part of the radiation 101 may be converted into luminescent material light. Then the system light 1001 may comprise luminescent material light and optionally radiation 101. The lamp or luminaire may be configured to provide light 1201, which may comprise or essentially consist of the radiation 101, though in alternative embodiments the light 1201 may comprise luminescent material light and optionally radiation 101.

Fig. lb schematically depicts a coaxial design of the DBD lamp 100, along a length thereof.

Fig. 1c schematically depicts a flat lamp design of the DBD lamp 100. Fig. Id schematically depicts an embodiment, of the dielectric barrier based radiation generating system 1000 further comprising an ignition aiding device control system 320 configured to switch off only the ignition aiding device 200 after operation of the ignition aiding device 200 at a predetermined minimum voltage during a predetermined minimum time or on the basis of a control signal.

Here, by way of example the design of Fig. la is chosen. However, this embodiment is not limited to this specific design.

The ignition aiding device control system 320 may comprise a relay.

Fig. le schematically depicts an embodiment of a dielectric barrier based radiation generating system 1000 comprising a dielectric barrier discharge lamp 100, an ignition aiding device 200, and a control system 300. Especially, the dielectric barrier discharge lamp 100 comprises a discharge vessel 130 (comprising a discharge vessel filling), a first discharge lamp electrode 110, and a second discharge lamp electrode 120. At least part of the discharge vessel 130 is transmissive for radiation having a first wavelength i. The dielectric barrier discharge lamp 100 is configured to emit during operation of the dielectric barrier discharge lamp 100 dielectric barrier discharge lamp radiation 101. The ignition aiding device 200 comprises a ceramic vessel 230 (containing a ceramic vessel space 235 comprising a ceramic vessel filling), a first ignition aiding device electrode 210, and a second ignition aiding device electrode 220. The first ignition aiding electrode 210 may extend into the ceramic vessel space 235. The second ignition aiding device electrode 220 may be configured external from the ceramic vessel 230. Especially, the ceramic vessel filling comprises a noble gas.

The control system 300 may comprises a dielectric barrier discharge lamp control system 310 functionally coupled to one or more of the first discharge lamp electrode 110 and the second discharge lamp electrode 120. Alternatively or additionally, especially additionally, the control system 300 may comprise an ignition aiding device control system 320 functionally coupled to one or more of the first ignition aiding device electrode 210 and the second ignition aiding device electrode 220.

The control system 300 is configured to control the dielectric barrier discharge lamp 100 and the ignition aiding device 200. The control system 300 is configured to switch off only the ignition aiding device 200 after operation of the ignition aiding device 200 at a predetermined minimum voltage during a predetermined minimum time or on the basis of a control signal, and wherein the dielectric barrier discharge lamp control system 310 and the ignition aiding device control system 320 comprise drivers. References 1310 and 1320 refer to the respective drivers. Reference 315 refers to an option sensor.

In embodiments, the control system 300, such as especially in embodiments the ignition aiding device control system, may be configured to switch off the ignition aiding device (a) after operation of the ignition aiding device at a predetermined minimum voltage during a predetermined minimum time or (b) on the basis of a control signal (or both may be used as input). The control signal may in embodiments be provided by sensor 315. The sensor 315 may be configured to sense the dielectric barrier discharge lamp radiation. In embodiments, a control system may, on the basis of the sensor signal of the sensor, define that the dielectric barrier based is operating as desired (i.e. especially started). If so, the control system may switch off the electric circuit related to the ignition aiding device. The control system may be comprised by the ignition aiding device control system, or another control system. Alternatively or additionally, a control system may control the operation of the dielectric barrier discharge lamp. When the dielectric barrier discharge lamp is operating as desired, the current (shape) through and/or voltage over the dielectric barrier discharge lamp may have changed from what it was just before the lamp was ignited. In embodiments, an analysis of the shape, of e.g. the current, may reveal that the lamp is operating. When the control system defines that the dielectric barrier discharge lamp is operating as desired, the control system may switch off the electric circuit related to the ignition aiding device.

Referring to Figs, la-le, some further embodiments are described here below. In embodiments, the dielectric barrier discharge lamp 100 may be configured to emit dielectric barrier discharge lamp radiation 101 when the first discharge lamp electrode 110 and the second discharge lamp electrode 120 are subjected to a pulsed first potential difference AVi. Especially, the ignition aiding device 200 may be configured to emit radiation 201 having the first wavelength i when the first ignition aiding device electrode 210, and the second ignition aiding device electrode 220 are subjected to a predetermined second potential difference AV2. In embodiments, AVi= AV2, and wherein AVi is at least 1 kV. In embodiments, the dielectric barrier discharge lamp 100 is configured to emit dielectric barrier discharge lamp radiation 101 having a wavelength selected from the range of 200-230 nm, and the first wavelength i is selected from the range of 250-400 nm. In embodiments, the first discharge lamp electrode 110 is a grounded electrode. As indicated above, in embodiments the dielectric barrier based radiation generating system 1000 may further comprise a control system 300, configured to control the dielectric barrier discharge lamp 100. In embodiments, the ceramic vessel filling comprises Argon. In specific embodiments, the ceramic vessel filling comprises less than 10,000 ppm other gasses. In embodiments, the ceramic vessel 230 comprises AI2O3 ceramic material; and wherein the AI2O3 ceramic material comprises MgO and E Ch. In embodiments, the first ignition aiding device electrode 210 comprises a niobium electrode, In embodiments, the second ignition aiding device electrode 220 comprises a molybdenum electrode. In embodiments, the second ignition aiding device electrode 220 comprises one or more coils enclosing the ceramic vessel 230. In embodiments, the second ignition aiding device electrode 220 comprises a molybdenum wire.

An embodiment of the ignition aiding device 200 is schematically depicted in Fig. 2. The ceramic vessel space 235 may essentially be defined by a (ceramic) vessel wall comprising ceramic material 231. The vessel wall is especially transmissive for radiation (especially having the first wavelength i) generated in the ceramic vessel space 235 (during operation thereof).

Fig. 3 schematically depicts an embodiment of a lamp 1200 comprising the dielectric barrier based radiation generating system 1000 as defined herein. The lamp 1200 is configured to emit radiation 1201. The radiation 1201 may in specific embodiments comprise dielectric barrier discharge lamp radiation 101. In such embodiments, the lamp 1200 may be used for disinfection. In other embodiments, the radiation 1201 may comprise luminescent material light. Especially, in such embodiments the lamp 1200 may be used for lighting. Though not shown in detail in Fig. 3, in specific embodiments the dielectric barrier based radiation generating system 1000 has a design selected from an axial design, a coaxial design, or a plate-like design. Reference 325 refers to a sensor, such as e.g. a movement sensor or a presence sensor (see also above for embodiments of possible sensors. The control system 300 may control the dielectric barrier based radiation generating system 1000 (or the lamp) for instance as function of the sensor signal.

With the dielectric barrier discharge lamp radiation 101, the invention provides a method for treating a gas or a surface, the method comprising providing dielectric barrier discharge lamp radiation 101 to the gas or the surface with the dielectric barrier based radiation generating system 1000 or the lamp 1200 (as respectively described herein).

The term “plurality” refers to two or more.

The terms “substantially” or “essentially” herein, and similar terms, will be understood by the person skilled in the art. The terms “substantially” or “essentially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially or essentially may also be removed. Where applicable, the term “substantially” or the term “essentially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%.

The term “comprise” also includes embodiments wherein the term “comprises” means “consists of’.

The term “and/or” especially relates to one or more of the items mentioned before and after “and/or”. For instance, a phrase “item 1 and/or item 2” and similar phrases may relate to one or more of item 1 and item 2. The term "comprising" may in an embodiment refer to "consisting of but may in another embodiment also refer to "containing at least the defined species and optionally one or more other species".

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.

The devices, apparatus, or systems may herein amongst others be described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation, or devices, apparatus, or systems in operation.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”.

The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a device claim, or an apparatus claim, or a system claim, enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

The invention also provides a control system that may control the device, apparatus, or system, or that may execute the herein described method or process. Yet further, the invention also provides a computer program product, when running on a computer which is functionally coupled to or comprised by the device, apparatus, or system, controls one or more controllable elements of such device, apparatus, or system.

The invention further applies to a device, apparatus, or system comprising one or more of the characterizing features described in the description and/or shown in the attached drawings. The invention further pertains to a method or process comprising one or more of the characterizing features described in the description and/or shown in the attached drawings.

The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined. Furthermore, some of the features can form the basis for one or more divisional applications.