High-frequency plasma light source

Abstract

The invention relates to a high-frequency plasma light source (1) in which, in the operating state, a plasma is formed which is quasi-capacitively coupled by at least two plasma anchors (6, 7), and thus the regions of the plasma with the highest energy density are spatially decoupled from the plasma anchors (6, 7), wherein the high-frequency plasma light source (1) - a pressure chamber (5) with a gaseous medium, in which the light-emitting plasma is formed in the operating state, - an assembly (4) of an impedance transformer connected to the pressure chamber (5), which assembly has a coupling pin (8) for coupling electromagnetic waves into the high-frequency plasma light source (1) and a coaxial conductor (9) with an inner conductor (9a) and an outer conductor (9b), wherein a dielectric pressure termination element (13) and at least one electrically conductive or dielectric connection (10, 12) are present between the inner conductor (9a) and the outer conductor (9b), - an inner conductor plasma armature (6) which projects into the pressure chamber (5) and is electrically and mechanically connected to the inner conductor (9a) of the coaxial conductor (9) and - an outer conductor plasma armature (7) having a first end (7a) arranged within the pressure chamber (5) and another end (7b) mechanically connected to the inner surface of the pressure chamber (5).

Description

[0001] The invention relates to a high-frequency plasma light source in which, in the operating state, a plasma is formed which is quasi-capacitively coupled by at least two plasma anchors, and thus the regions of the plasma with the highest energy density are spatially decoupled from the plasma anchors.

[0002] US 2007 / 0 194 678 A1 describes a light source with a coaxial waveguide consisting of an inner and an outer metal conductor separated by quartz glass. The lamp has a discharge chamber filled with a noble gas and a luminescent substance. Conductors made of tungsten and molybdenum extend into the discharge chamber. This arrangement enables light emission by plasma, excited by electromagnetic waves in the waveguide. Disadvantages of this arrangement are the lack of impedance matching in the waveguide and the complex construction.

[0003] US 2012 / 0 074 839 A1 discloses a discharge lamp comprising a discharge chamber with a luminous substance enclosed therein, as well as an antenna arrangement that guides electromagnetic waves into the discharge chamber. An impedance section is also described. This impedance section refers to a part of the discharge lamp specifically designed to keep the electromagnetic waves emanating from the antenna within the lamp and prevent these waves from escaping. The impedance section consists of a charging coil wound around the part of the antenna that protrudes from the discharge chamber. This coil acts as a type of electromagnetic barrier that keeps the microwave energy within the discharge chamber. A disadvantage of this light source is the complex impedance matching in the waveguide required to achieve high luminous efficiency.

[0004] DE 10 2007 057 581 A1 also describes a high-frequency lamp with an electrode extending into a discharge chamber. DE 10 2009 022 755 A1 discloses an electrodeless high-frequency high-pressure lamp. DE 10 2013 110 985 A1 describes a high-frequency lamp with multiple electrodes extending into a discharge chamber.

[0005] The object of the invention is to provide a high-frequency plasma light source in which the disadvantages of the prior art are eliminated.

[0006] This object is achieved with the high-frequency plasma light source according to the features of claim 1. Advantageous embodiments are the subject of subclaims.

[0007] In the high-frequency plasma light source according to the invention, a plasma is formed in the operating state that is quasi-capacitively coupled by at least two plasma anchors. Thus, the regions of the plasma with the highest energy density are spatially decoupled from the plasma anchors.

[0008] A quasi-capacitively coupled high-frequency plasma is a plasma region separated from the plasma anchors by a gas region with low plasma density. In a quasi-capacitively coupled plasma, small inductive and resistive effects also occur in the coupling region, while the majority of the plasma coupling occurs capacitively. In practice, this means that energy coupling into the plasma does not occur exclusively through the displacement of charge carriers in the electric field (as in an ideal capacitor), but that collision processes and other interactions between the particles in the plasma also contribute to energy transfer. This coupling region lies in the range of 2–80 degrees of the electrical length of the high-frequency signal.

[0009] The high-frequency plasma light source according to the invention comprises a pressure chamber containing a gaseous medium, in which the light-emitting plasma is formed during operation. According to the invention, an impedance transformation assembly is connected to the pressure chamber. This assembly has a coupling pin for coupling electromagnetic waves into the high-frequency plasma light source. Furthermore, the assembly has a coaxial conductor with an inner conductor and an outer conductor, with a dielectric pressure termination element and at least one electrically conductive or dielectric connection being present between the inner conductor and the outer conductor. The electrically conductive or dielectric connection serves to match the impedance.

[0010] The term “operating state” refers to the state of the high-frequency plasma light source in which a stable, light-emitting plasma is generated within the pressure chamber.

[0011] According to the invention, the high-frequency plasma light source further comprises a first plasma armature and a second plasma armature. The first plasma armature extends into the pressure chamber, such that a first end is arranged within the pressure chamber. The other end is electrically and mechanically connected to the inner conductor of the coaxial conductor. The first plasma armature thus serves, at least in sections, as the inner conductor of the coaxial conductor. In the second plasma armature, a first end is arranged within the pressure chamber. The other end of the second plasma armature is mechanically connected to the inner surface of the pressure chamber. Optionally, this connection can also be electrical.

[0012] A plasma in the high-frequency plasma light source according to the invention is essentially the spatial region of an ionized gas medium generated within the pressure chamber by the action of high-frequency electromagnetic energy. The energy coupled into the pressure chamber separates electrons from atoms or molecules of the gas in a specific spatial region of the pressure chamber, thus forming a mixture of electrons, ions, neutral atoms, or molecules. In contrast to DC and low-frequency AC plasmas, the electrically conductive particles in a high-frequency plasma are quasi-stationary because the free paths are very short. Through the energy input and collision processes between the particles, components of this mixture are raised to higher energy levels. When they fall back to lower energy levels (recombination), photons are emitted according to the energy difference between the energy levels.

[0013] The plasma is ignited in the pressure chamber in an area of ​​locally elevated electric field strength. The plasma is then heated and maintained by coupling the electromagnetic energy with as little reflection as possible. In the high-frequency plasma light source according to the invention, the plasma is ignited and maintained between the two plasma anchors, with the plasma located between the two plasma anchors and the regions of the plasma with the highest energy density spatially decoupled from the plasma anchors.

[0014] The high-frequency plasma light source according to the invention therefore has a significantly longer service life, since the plasma armatures are affected by electrode burn-up to a significantly lesser extent, in contrast to the electrodes of known discharge lamps which are operated by means of direct current or low-frequency alternating voltage and are referred to below as direct current discharge lamps.

[0015] A plasma armature within the meaning of the invention is a type of electrode, whereby the function of an electrode within the meaning of the invention differs from an electrode of a direct current discharge lamp, in which an arc is formed between electrodes. The arc in a direct current discharge lamp is essentially created by a current flow between an anode and a cathode. Thus, in known direct current discharge lamps, a high current flows from the interior of the electrodes through the surface of the electrodes. In the present invention, as described above, the energy input is achieved by high-frequency electromagnetic fields. In the operating state of the high-frequency plasma light source according to the invention, therefore, unlike in direct current discharge lamps, no current flows from the interior of the plasma armature through the surface of the plasma armature.This ensures that, according to the invention, no work function of charge carriers from the plasma armature needs to be overcome during operation. Heating of the plasma armature due to the work function is thus prevented.

[0016] One advantage resulting from the high-frequency plasma light source according to the invention is that significantly higher power densities can be achieved, since the plasma armatures in the invention are not heated by the work function of the charge carriers, as is the case with the electrodes in conventional DC discharge lamps. Thus, in the invention, hardly any energy is spent on the work function of electrons, meaning that almost all of the coupled power is available for heating the plasma. This enables extremely efficient operation of a high-frequency plasma light source.

[0017] The high-frequency plasma light source according to the invention also makes it possible to generate improved temporal stability of the plasma. In contrast to known direct current discharge lamps, the temporally varying work function of the charge carriers at the electrodes, which leads to instabilities and movements of the plasma, plays no role in the invention.

[0018] To improve the stability of the plasma between the first plasma anchor and the second plasma anchor and to increase the decoupling of the plasma from the plasma anchors, the opposing surfaces of the plasma anchors can have predetermined shapes. In a first variant, the first end of the first plasma anchor, i.e. the end arranged within the pressure chamber, can have a flat surface. In this variant, the first end of the second plasma anchor is designed as a convex, e.g. pointed, end and lies opposite the first end of the first plasma anchor. Of course, in an expedient embodiment of this first variant, it is also possible for the first end of the first plasma anchor to have a convex shape.

[0019] In a second variant, the first end of the first plasma armature is designed as a concave surface. The first end of the second plasma armature is also designed as a concave surface and is arranged opposite the first end of the first plasma armature. Any combination of concave and convex plasma armatures is also possible. Ideally, a plasma with a radially symmetric structure is formed, with a low power density on the surface and a power density in the core that continuously increases or remains constant with decreasing diameter.

[0020] The gaseous medium used in the high-frequency plasma light source according to the invention can be, for example, noble gases, mercury, deuterium, or gas mixtures thereof. To adjust the emitted spectrum, additives such as metal halides can optionally be added to the gaseous medium. The operating pressure within the pressure chamber can vary between 1 mbar and 250 bar, depending on the application. The frequency range of the electromagnetic energy used to feed the plasma can be between 0.01 GHz and 100 GHz. In one embodiment of the invention, the high-frequency plasma light source has a channel for filling the gaseous medium into the pressure chamber.

[0021] The first plasma anchor and the second plasma anchor can be made of tungsten or a tungsten alloy, thus exhibiting a high melting temperature. For example, a plasma anchor can be made of pure tungsten or of tungsten with oxide additives such as zirconium oxide, thorium dioxide, lanthanum oxide, or mixed oxides of rare earth elements.

[0022] In the high-frequency plasma light source according to the invention, the impedance transformation assembly, hereinafter also referred to as an impedance transformer, comprises a coupling pin for coupling high-frequency electromagnetic waves into the high-frequency plasma light source, a coaxial conductor with an inner conductor and an outer conductor, and inductive and / or capacitive elements. The impedance transformer serves, on the one hand, as a hermetic seal for the pressure chamber. On the other hand, the impedance transformer enables low-reflection coupling of the high-frequency electromagnetic waves into the pressure chamber. In the operating state, this enables a virtually loss-free coupling of the power of the high-frequency electromagnetic wave into the plasma, thereby heating and maintaining the plasma.

[0023] In one embodiment of the invention, the coupling pin is mechanically and electrically connected to the inner conductor of the coaxial conductor. This ensures that the electromagnetic wave coupled into the high-frequency plasma light source via the coupling pin can be guided into the impedance transformer with virtually no loss.

[0024] In one variant of the invention, the coupling pin, the inner conductor of the coaxial conductor, and the first and second plasma armatures are arranged on a common axis. This enables a compact design, optimal transmission of electromagnetic energy, and optimal optical light yield.

[0025] To seal the high-frequency plasma light source from the environment, the dielectric pressure sealing element radially encloses the coupling pin. This hermetically seals the areas between the inner and outer conductors of the coaxial cable, as well as the adjacent pressure chamber, from the environment.

[0026] A further embodiment of the invention provides that the at least one electrical or dielectric connection between the inner conductor and the outer conductor of the coaxial conductor is formed by a single component. This single component, hereinafter referred to as an impedance element, has a coaxial inner conductor section and at least one connecting web that electrically or dielectrically connects the coaxial inner conductor section to the outer conductor of the coaxial conductor. The coaxial inner conductor section is understood to be a section of the inner conductor of the coaxial conductor of the impedance transformer.

[0027] The impedance element essentially establishes an electrical or dielectric connection between the inner and outer conductors of the coaxial conductor and serves to match the impedance. This ensures virtually loss-free coupling of the electromagnetic power into the plasma. The at least one connecting web forms a radial connection between the coaxial inner conductor section of the inductive or capacitive impedance element and the outer conductor of the coaxial conductor. If multiple connecting webs are present, these multiple connecting webs can be arranged at one point and / or along a longitudinal direction of the coaxial inner conductor section radially around this coaxial inner conductor section.

[0028] Advantageously, the first plasma armature and the coupling pin are arranged on opposite sides of the impedance transformer and thus on opposite sides of the impedance element. This enables a modular design of the high-frequency plasma light source, allowing individual components to be quickly replaced or serviced.

[0029] During operation, high temperatures are generated at the plasma armatures while maintaining the hot plasma. Effective heat dissipation from the first plasma armature ensures a long service life of the plasma armatures and a consistent light output. Furthermore, degradation of light quality over time is reduced. Furthermore, optimal heat dissipation allows for increased power input and thus increased plasma power densities, resulting in an increase in overall irradiance. Furthermore, optimal cooling can increase the cost-effectiveness of the light source by reducing maintenance costs and downtime.

[0030] Embodiments of the invention are described below which contribute to the dissipation of heat from the plasma armatures. One embodiment provides that the at least one connecting web of the impedance element and the coaxial inner conductor section of the short-circuit element have cooling channels which are connected to cooling channels in the impedance transformer. In an impedance element with at least two connecting webs, the cooling channel of the coaxial inner conductor section serves, at least in sections, as a connecting channel between the cooling channels of the at least two connecting webs. The cooling channel of the coaxial inner conductor section can form a cooling conductor section along the longitudinal direction of the coaxial inner conductor section. Thus, heat can be dissipated from the first plasma armature via the impedance element to the impedance transformer. Water, an insulating oil, or nitrogen can expediently be provided for cooling.

[0031] In a further embodiment, it can be provided that a cooling channel is provided in the first plasma armature, expediently along its longitudinal direction, which cooling channel is directly connected to at least one cooling channel of the impedance element.

[0032] Another embodiment provides that the first plasma armature has a cooling channel, expediently along its longitudinal direction, which is connected to at least one cooling channel of the impedance transformer. Thus, the heat from the first plasma armature is dissipated directly toward the impedance transformer. The at least one cooling channel can be designed as a connecting web and represent both a mechanical connection and an additional electrical connection.

[0033] In a further development of the cooling system, it is possible for the first plasma armature and the coaxial inner conductor section to be designed as a heat pipe. In this case, the first plasma armature and the coaxial inner conductor section have a connected, closed cavity which extends from the first end of the first plasma armature across the opposite other end of the first plasma armature into the coaxial inner conductor section. In the operating state, the first end of the first plasma armature faces the thermally hot plasma and the other end faces the impedance element. The heat generated at the first end of the first plasma armature is transported via the heat pipe to the impedance element and dissipated via a cooling channel in the at least one connecting web to the impedance transformer. It is expedient for the heat pipe to be formed only in the first plasma armature.

[0034] A further embodiment of the invention provides that the pressure chamber has a reflector and a pressure-tight window opposite the reflector for light emission. The reflector serves to reflect the light emitted by the plasma into the area outside the pressure chamber.

[0035] The optical axis of the reflector conveniently coincides with the axis of the first plasma anchor and the focal point of the reflector lies in the spatial region of the highest energy density of the plasma in the operating state of the high-frequency plasma light source.

[0036] In one variant of the invention, the reflector can be an elliptical reflector, a parabolic reflector, or a freeform reflector. The reflector can form the inner surface of the pressure chamber. However, it is also possible for the reflector to be a separate component inside or outside a pressure chamber designed as a glass body. The pressure-tight window for the light exit can also be a convex lens, a concave lens, or an aspherical freeform lens. In the case of a glass body as a pressure chamber, the lens can also be integrated into the glass body. The window can be made of quartz or sapphire.

[0037] According to the invention, one or more mechanical mounts for the second plasma armature are provided, which are attached to the inner surface of the pressure chamber. The one or more mechanical mounts are advantageously designed such that they only slightly shade the light emitted by the plasma.

[0038] In a further variant of the high-frequency plasma light source according to the invention, the one or more mechanical mounts are designed such that, during operation, the heat generated in the second plasma armature can be optimally dissipated. For this purpose, the one or more mechanical mounts and the second plasma armature have at least one cooling channel, which can be connected to the cooling channel of the first plasma armature.

[0039] The invention and further advantages of the invention are explained with reference to the drawings. They show: Fig. 1 shows a schematic high-frequency plasma light source according to the invention in a sectional view; Fig. 2 shows several exemplary schematic embodiments of the first plasma anchor and the second plasma anchor; Fig. 3 shows several exemplary schematic embodiments of an impedance element; Fig. 4 an exemplary schematic representation of a cooling system for a first plasma armature with heat pipe.

[0040] Fig. Figure 1 shows a schematic cross-sectional view of a high-frequency plasma light source 1 according to the invention. The high-frequency plasma light source 1 comprises a lamp body 2, a reflector 3, and an impedance transformer 4. Furthermore, the high-frequency plasma light source 1 comprises a pressure chamber 5 in which a first plasma armature 6 and a second plasma armature 7 are arranged. Between the two plasma armatures 6, 7, the light-emitting plasma (not shown) is ignited and heated during the operating state of the high-frequency plasma light source 1.

[0041] The impedance transformer 4 has a coupling pin 8, a coaxial conductor 9 with an inner conductor 9a and an outer conductor 9b as well as an impedance element 10. In the Fig. 1, the impedance transformer 4 is shown as an example in two parts with an upper part 4a and a lower part 4b, wherein the impedance element 10 is positioned in the upper part 4a and the first plasma armature 6 is positioned at least in part in the lower part 4b. However, it is possible for the impedance transformer 4 to be designed in one piece. The coupling pin 8 is arranged on a common axis Z with the inner conductor 9a of the coaxial conductor 9, the first plasma armature 6, and the second plasma armature 7. In this case, the coupling pin 8 is mechanically and electrically connected to the inner conductor 9a of the coaxial conductor 9. The coupling pin 8 thus represents a partial section of the inner conductor 9a. The coupling pin 8 and the inner conductor 9a of the coaxial conductor 9 can be designed in one piece. Electromagnetic energy from a high-frequency source (not shown) is fed into the pressure chamber 5 via the coupling pin 8 via the coaxial conductor 9 and the first plasma armature 6.

[0042] A channel 15 is formed in the impedance transformer 4, through which a gaseous medium (not shown) can be introduced into the high-frequency plasma light source 1. In Fig. 1, this channel 15 is formed, for example, in the area of ​​the coaxial conductor 9, so that the gaseous medium can be introduced into the space 14 between the inner conductor 9a and outer conductor 9b of the coaxial conductor 9 and the adjacent pressure chamber 5. However, it is also possible for the channel 15 to be formed in the area of ​​the reflector 3 or the lamp body 2 (not shown). For example, in Fig. 1, the gap 14 between the inner conductor 9a and the outer conductor 9b of the coaxial conductor 9 and the pressure chamber 5 are directly connected to each other via an opening 16 in the reflector 3. However, it is possible for the pressure chamber 5 to be sealed off from the gap 14 by means of a further dielectric pressure sealing element (not shown).

[0043] The impedance element 10 consists of a coaxial inner conductor section 11 and, for example, two connecting webs 12, which represent a mechanical and electrical connection between the coaxial inner conductor section 11 and the outer conductor 9b of the coaxial conductor 9. The coaxial inner conductor section 11 thus represents a further subsection of the inner conductor 9a of the coaxial conductor 9. The two connecting webs 12 each have a cooling channel 20, which is connected to a cooling channel 22 in the impedance transformer 4. Heat can be dissipated from the first plasma armature 6 by means of these cooling channels 20, 22.

[0044] The first plasma armature 6 is arranged on the side of the impedance element 10 opposite the coupling pin 8. The first plasma armature 6 protrudes through the opening 16 of the reflector 3 into the pressure chamber 5, so that the first end 6a of the first plasma armature 6 is arranged within the pressure chamber 5. The other end 6b of the first plasma armature 6 is electrically and mechanically connected to the impedance element 10. Fig. 1, the first plasma armature 6 protrudes, for example, into the coaxial conductor 9, so that the other end 6b is arranged within the coaxial conductor 9. Thus, the first plasma armature 6 forms a further section of the inner conductor 9a of the coaxial conductor 9.

[0045] An annular dielectric pressure sealing element 13 radially surrounds the coupling pin 8 and seals the gap 14 between the inner conductor 9a and the outer conductor 9b of the coaxial conductor 9. This seals the high-frequency plasma light source 1 from the external environment.

[0046] The reflector 3 and the lamp body 2 together form the pressure chamber 5. The reflector 3 is connected to the impedance transformer 4 and, as described above, has an opening 16 through which the first plasma armature 6 projects into the pressure chamber 5. On the opposite side of the opening 16, the lamp body 2 has a further opening 17 with a window 18 through which the light emitted by the plasma can exit the pressure chamber 5. The reflector 3 and the lamp body 2 and / or the reflector 3 and the impedance transformer 4 can also be formed as a single piece.

[0047] The second plasma armature 7 is arranged within the pressure chamber 5. The first end 7a of the second plasma armature 7 is opposite the first end 6a of the first plasma armature 6. Between these two first ends 6a, 7a of the plasma armatures 6, 7, the plasma is formed in the operating state. The second plasma armature 7 is connected by several Fig. 1 is held, for example, by two brackets 19. These brackets 19 are connected to the lamp body 2.

[0048] Fig. Figure 2a schematically shows a section of a pressure chamber 5 with a first exemplary embodiment of a first plasma armature 6 and a second plasma armature 7. As already described above, the first plasma armature 6 protrudes through an opening 16 in the reflector 3 into the pressure chamber 5, so that the first end 6a of the first plasma armature 6 and the first end 7a of the second plasma armature 7 are opposite each other. For reasons of clarity, only the first end 7a of the second plasma armature 7 is shown.

[0049] The two plasma anchors 6, 7 lie on a common axis Z. The focal point 25 of the reflector 3 also lies on this common axis Z. The position of the focal point 25 is essentially determined by the shape of the surface 3a of the reflector 3. The focal point 25 is located between the two first ends 6a, 7a of the plasma anchors 6, 7.

[0050] The opposite surfaces of the first ends 6a, 7a of the plasma anchors 6, 7 are in Fig. 2a concave.

[0051] Fig. Figure 2b shows schematically the section of a pressure chamber 5 with a second exemplary embodiment of a first plasma anchor 6 and a second plasma anchor 7. The arrangement of the plasma anchors 6, 7 corresponds to the arrangement in Fig. 2a. To avoid repetition, reference is made to the corresponding embodiment. The two first ends 6a, 7a are each flat or planar. For example, the cross-section of the first end 7a of the second plasma armature 7 is smaller than the cross-section of the first end of the first plasma armature 6.

[0052] Fig. Figure 2c shows schematically the section of a pressure chamber 5 with a third exemplary embodiment of a first plasma anchor 6 and a second plasma anchor 7. The arrangement of the plasma anchors 6, 7 corresponds to the arrangement in Fig. 2a or

[0053] Fig. 2b. To avoid repetition, reference is made to the relevant section. In contrast to Fig. 2a and Fig. 2b, the opposite ends 6a, 7a of the plasma anchors 6, 7 have different shapes. In Fig. 2c, the first end 6a of the first plasma armature 6 is flat or planar. In contrast, the first end 7a of the second plasma armature 7 is designed with a point.

[0054] The Fig. 3a to 3d show various embodiments of an impedance element 10. Each figure has three representations, wherein the left representation shows a perspective view, the middle representation a plan view and the right representation a sectional view of the exemplary impedance element 10 along a section axis AA.

[0055] Fig. Figure 3a shows an impedance element 10 with two connecting webs 12 and a coaxial inner conductor section 11. The connecting webs 12 are arranged radially on the coaxial inner conductor section 11 and, for example, are at an angle of 180° to each other. Furthermore, the connecting webs 12 lie on a common axis X, which runs perpendicular to the longitudinal orientation L of the coaxial inner conductor section 11.

[0056] The two connecting webs 12 each have a cooling channel 20, with one cooling channel 20 serving as an inlet for a cooling medium (not shown) and the other cooling channel 20 serving as the outlet for the cooling medium. The coaxial inner conductor section 11 of the impedance element 10 also has a cooling channel 21, which is connected to the two cooling channels 20 of the connecting webs 12. Since the cooling channels 20 of the connecting webs 12 lie on the common axis X, the path of the coolant through the cooling channel 21 of the coaxial inner conductor section 11 is only short.

[0057] Fig. Figure 3b shows another impedance element 10 with two connecting webs 12 and a coaxial inner conductor section 11. The connecting webs 12 are also arranged radially on the coaxial inner conductor section 11, but the angle between the connecting webs is between 0° and 180°. The connecting webs 12 are also offset from one another along the longitudinal direction L of the coaxial inner conductor section 11. As shown in Fig. 3a, the connecting webs 12 and the coaxial inner conductor section 11 have cooling channels 20, 21 that are interconnected, with one cooling channel 20 serving as an inlet for a cooling medium (not shown) and the other cooling channel 20 serving as an outlet for the cooling medium. Due to the arrangement of the cooling channels 20 of the connecting webs 12, the coolant is guided through the cooling channel 21 of the coaxial inner conductor section 11. This further improves heat dissipation.

[0058] Fig. 3c shows an impedance element 10 with three connecting webs 12 and a coaxial inner conductor section 11. As already in Fig. 3a and Fig. 3b, the connecting webs 12 with their cooling channels 20 are arranged radially on the coaxial inner conductor section 11 and along the longitudinal direction L of the coaxial inner conductor section 11. The connecting webs 12 are, for example, at an angle of 120° to one another. Fig. 3c, the cooling channels 20 are arranged, for example, in three planes E1, E2, E3 that run perpendicular to the longitudinal axis L of the coaxial inner conductor section 11 and are spaced apart from one another. Either one or two cooling channels 20 can serve as inlet or outlet, thereby further improving the effectiveness of heat dissipation.

[0059] Fig. 3d shows an impedance element 10 with four connecting webs 12 and a coaxial inner conductor section 11 with their respective cooling channels 20, 21. The connecting webs 12 are as already shown in the Fig. 3a-3c are arranged radially on the coaxial inner conductor section 11 and along the longitudinal direction L of the coaxial inner conductor section 11. Two cooling channels 20 are expediently formed as inlets and two cooling channels 20 as outlets of a coolant. In the Fig. 3d, the cooling channels 20 are arranged, for example, in two planes E1, E2 that run perpendicular to the longitudinal axis L of the coaxial inner conductor section 11 and are spaced apart from one another. The cooling channels 20 of one plane E1, E2 are located opposite one another, i.e., they lie on a common axis X. The cooling channels 20 of one plane E1, E2 expediently serve as the inlet and the cooling channels 20 of the other plane E2, E1 serve as the outlet for a coolant. This enables effective coolant transport through the cooling channel 21 of the coaxial inner conductor section 11.

[0060] Fig. 4 shows an exemplary embodiment of a cooling system for a first plasma armature 6 with heat pipe 23. Three representations are shown, the left representation showing a perspective view, the middle view a plan view and the right representation a sectional view along a section axis AA.

[0061] Shown is the upper part 4a of a mirror-symmetrical impedance transformer 4 with an impedance element 10 positioned on the rotation axis Z of the impedance transformer 4. The first plasma armature 6 is located on the rotation axis Z, directly adjacent to the coaxial inner conductor section 11. The first plasma armature 6 of the coaxial inner conductor section 11 of the impedance element 10 is designed as a heat pipe 23. The heat pipe 23 is formed from a cavity 24 that extends within the first plasma armature 6 to within the coaxial inner conductor section 11. The cavity 24 is sealed off from the environment.

[0062] The impedance element 10 has two connecting webs 12 with two connected cooling channels 20, which connect the impedance element 10 to the cooling channels 22 in the upper part 4a of the impedance transformer 4. Thus, heat is dissipated from the first plasma armature 6 via the heat pipe 23, the cooling channels 20 of the connecting webs 12 of the impedance element 10, and the cooling channels 22 in the upper part 4a of the impedance transformer 4. List of reference symbols 1 high-frequency plasma light source 2 lamp bodies 3 Reflector 3a Reflector surface 4 Impedance transformer 4a Upper part of the impedance transformer 4b Lower part of the impedance transformer 5 pressure chamber 6 First Plasma Anchors 6a first end of the first plasma anchor 6b other end of the first plasma anchor 7 Second plasma anchors 7a first end of the second plasma anchor 7b other end of the second plasma anchor 8 coupling pin 9 coaxial conductors 9a Inner conductor of the coaxial conductor 9b Outer conductor of the coaxial conductor 10 Impedance element 11 Coaxial inner conductor section 12 connecting bridge 13 Pressure closure element 14 gap 15 Cooling medium supply channel 16 Opening 17 Further opening 18 windows 19 Bracket 20 Cooling channel in the connecting bridge 21 Cooling channel in the coaxial inner conductor section 22 Cooling channel in the impedance transformer 23 Heat pipe 24 cavity 25 focus point L Longitudinal axis X common axis of the connecting webs E1 Level of connecting bridges E2 Level of connecting bridges Z common axis / rotation axis

Claims

[1] High frequency plasma light source (1) with - a pressure chamber (5) with a gaseous medium, in which a light-emitting quasi-capacitively coupled plasma is formed in the operating state, - two plasma anchors (6, 7) opposite each other in the pressure chamber (5), of which the quasi-capacitively coupled plasma is formed in the operating state, wherein the quasi-capacitively coupled plasma is a plasma region with the highest energy density, which is separated from the plasma anchors (6, 7) by a gas region with low plasma density, wherein the quasi-capacitively coupled plasma is an ionized gas medium generated by the action of high-frequency electromagnetic energy within the pressure chamber (5), wherein the energy coupling into the quasi-capacitively coupled plasma is not only effected by displacement of charge carriers in the electric field as in an ideal capacitor, but also by collision processes and other interactions between particles in the plasma, wherein no current flows from the interior of the plasma anchors (6, 7) through the surface of the plasma anchors (6, 7), - an assembly (4) of an impedance transformer (4) connected to the pressure chamber (5), which assembly has a coupling pin (8) and a coaxial conductor (9) with an inner conductor (9a) and an outer conductor (9b), wherein a dielectric pressure termination element (13) and at least one electrically conductive or dielectric connection (10, 12) are present between the inner conductor (9a) and the outer conductor (9b), wherein electromagnetic energy from a high-frequency source is supplied to the coaxial conductor (9) via the coupling pin (8), wherein the coupling pin (8) is electrically and mechanically connected to the inner conductor (9a) of the coaxial conductor (9), wherein the inner conductor (9a) of the coaxial conductor (9) is electrically and mechanically connected to the first (6) of the two plasma armatures (6, 7) which protrudes into the pressure chamber (5) in order to conduct the electromagnetic energy into the pressure chamber (5) and to couple it into the plasma, wherein the second plasma armature (7) comprises a first end (7a) arranged within the pressure chamber (5) and another end (7b) which is electrically or dielectrically and mechanically connected to the inner surface of the pressure chamber (5) via one or more supports (19), wherein the inner surface of the pressure chamber (5) is electrically or dielectrically and mechanically connected to the outer conductor (9b) of the coaxial conductor (9). [2] High-frequency plasma light source (1) according to claim 1, characterized bythat the coupling pin (8), the inner conductor (9a) of the coaxial conductor (9) and the first and second plasma armature (6, 7) lie on a common axis (Z). [3] High-frequency plasma light source (1) according to one of the preceding claims 1 to 2, characterized by that the dielectric pressure closure element (13) radially encloses the coupling pin (8) and thereby seals the high-frequency plasma light source (1) from the environment. [4] High-frequency plasma light source (1) according to one of the preceding claims 1 to 3, characterized by that the first plasma armature (6) is arranged on the side of the impedance element (10) opposite the coupling pin (8). [5] High-frequency plasma light source (1) according to one of the preceding claims 1 to 4, characterized bythat the at least one electrical or dielectric connection (10, 12) between the inner conductor (9a) and the outer conductor (9b) of the coaxial conductor (9) is formed by an impedance element (10) which has a coaxial inner conductor section (11) and at least one connecting web (12) which mechanically and electromagnetically connects the coaxial inner conductor section (11) to the outer conductor (9b) of the coaxial conductor (9). [6] High-frequency plasma light source (1) according to claim 5, characterized by that the at least one connecting web (12) and the coaxial inner conductor section (11) have interconnected cooling channels (20, 21) which are connected to at least one cooling channel (22) of the impedance transformer (4). [7] High-frequency plasma light source (1) according to one of the preceding claims 1 to 6, characterized bythat the first plasma armature (6) has a cooling channel which is directly connected to at least one cooling channel (22) of the impedance transformer (4). [8] High-frequency plasma light source (1) according to one of the preceding claims 5 to 7, characterized by that the first plasma armature (6) and the coaxial inner conductor section (11) of the impedance element (10) are designed as a heat pipe (23). [9] High-frequency plasma light source (1) according to one of the preceding claims, characterized by that the pressure chamber (5) has a reflector (3) and a pressure-tight window (18) opposite the reflector (3) for light exit. [10] High-frequency plasma light source (1) according to claim 9, characterized by that the optical axis of the reflector (3) coincides with the axis (Z) of the first plasma anchor (6) and the focal point (25) of the reflector (3) lies in the region of the highest energy density of the plasma in the operating state of the high-frequency plasma light source (1). [11] High-frequency plasma light source (1) according to one of the preceding claims 9 to 10, characterized by that the reflector (3) is an elliptical reflector, a parabolic reflector or a free-form reflector and the pressure-tight window (18) for light exit is a convex lens, a concave lens or an aspherical free-form lens. [12] High-frequency plasma light source (1) according to claims 8 and 7, characterized by that the mechanical supports (19) and the second plasma armature (7) have at least one cooling channel which can be connected to the cooling channel of the first plasma armature (6). [13] High-frequency plasma light source (1) according to one of the preceding claims, characterized by that the first plasma anchor (6) has a flat or convex surface at the first end (6a), which is opposite a pointed first end (7a) of the second plasma anchor (7). [14] High-frequency plasma light source (1) according to one of the preceding claims 1 to 12, characterized by that the first plasma anchor (6) has a concave surface at the first end (6a) which is opposite a concave surface at the first end (7a) of the second plasma anchor (7). [15] High-frequency plasma light source (1) according to one of the preceding claims, characterized by that a channel (15) is provided for filling a gaseous medium into the pressure chamber (5).

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