阅读说明：本技术 用于气体放电灯的电极和气体放电灯 (Electrode for gas discharge lamp and gas discharge lamp ) 是由 玛利亚·尼利乌斯 赖纳·科格尔 亚当·科托维奇 于 2020-03-10 设计创作，主要内容包括：本发明涉及一种用于气体放电灯的电极,尤其是阳极(20),其中,电极(20)具有基体(22),所述基体包围多个腔室(221-223)。腔室(221-223)能够相对于电极(20)的纵向轴线(A)彼此平行或串联设置并且至少部分地填充有低熔点金属(26)、例如银或铜。通过将各个腔室(221-223)的数量、填充、形状和几何尺寸以及它们在基体(22)内的位置与电极(20)的相应设计适当匹配,能够改善基体(22)的散热,尤其是阳极平台(14)附近区域的散热。(The invention relates to an electrode, in particular an anode (20), for a gas discharge lamp, wherein the electrode (20) has a base body (22) which surrounds a plurality of chambers (221-. The chambers (221-. By appropriately matching the number, filling, shape and geometry of the individual chambers (221-223) and their position in the base body (22) to the corresponding design of the electrodes (20), the heat dissipation of the base body (22), in particular of the region in the vicinity of the anode platform (14), can be improved.)

1. An electrode (1, 2) for a gas discharge lamp (10), wherein the electrode (1, 2) has a base body which encloses at least two chambers.

2. The electrode (202) according to claim 1, wherein the chambers (K1-K4) or at least a part thereof are arranged in series with each other in the longitudinal extension of the substrate (22).

3. The electrode (2) according to claim 1 or 2, wherein the chambers (221, 222) or at least a part thereof are arranged parallel to each other in a longitudinal extension direction (a) of the base body (22).

4. The electrode (2) according to any of the preceding claims, wherein the chamber (221, 222) or at least a part thereof is hermetically (air/gas) closed.

5. The electrode (2) according to any one of the preceding claims, wherein the chamber (221, 222) or at least a part thereof has (partial) a filling (26).

6. The electrode of claim 5, wherein the filler (26) comprises one or more thermally conductive components.

7. The electrode of claim 6, wherein the at least one thermally conductive component has a thermal conductivity greater than a thermal conductivity of the matrix.

8. The electrode of claim 6 or 7, wherein the at least one thermally conductive component comprises one or more metals having a melting point lower than the melting point of the substrate of the electrode.

9. The electrode (2) according to any of the preceding claims, wherein the base body comprises a container part (can) (22), wherein the chamber (221, 222) is provided in the container part (22).

10. An electrode (2, 20) according to claim 9, wherein the base body comprises a closing member (lid, plug) (24, 261, 262) and wherein the closing member (24, 261, 262) closes the container member (22).

11. An electrode (2, 20) according to claim 10, wherein the closing means (24, 261, 262) closes the chamber (221, 222) or at least a part of the chamber, optionally hermetically closes the chamber or at least a part of the chamber.

12. The electrode (20) according to claim 9 or 10, wherein each chamber (221, 222) is closed, optionally hermetically closed, with a separate closing member (plug) (261, 262).

13. An electrode (2, 20) according to any of claims 9 to 12, wherein the free end of the container part (22) is designed as an electrode platform (14) on which a discharge arc is formed during operation of the discharge lamp, and the closing part (24) or, if appropriate, the closing part (261, 262) is arranged opposite the electrode platform (14).

14. The electrode of claim 13, wherein at least one chamber extends as close as possible to the electrode platform without causing mechanical deformation of the electrode platform.

15. An electrode according to any of claims 9 to 14, wherein the or each of the closure members is/are provided with a screw thread.

16. The electrode (200) according to any of claims 9 to 15, wherein the closing means (266) or if necessary the closing means are sealed with solder (2661).

17. A gas discharge lamp (10) having at least one electrode (1, 2) according to any one of the preceding claims.

Technical Field

The invention relates to a discharge lamp and an electrode arranged therein. In particular, the invention relates to lamps having electrodes which are subject to high thermal loads, for example in the case of short-arc discharge lamps. Mercury discharge lamps (for example OSRAM) are mentioned here by way of example) And xenon gas discharge lamps (e.g. OSRAM)) They can also be used for lithographic applications (microchips, ICs, PCBs, LCD displays, etc.) or for projection applications (e.g. cinema projection). In principle, the invention can be used for all lamp-like light sources in which at least one electrode is arranged in a light-transmitting container (for example a glass bulb). In this connection, the invention can also be used in laser-based plasma light sources (so-called laser sustained plasma light sources).

Background

The electrodes, in particular the anode in the case of a dc lamp, are subject to high thermal loads during operation of the lamp. Therefore, a material having very high heat resistance, tungsten in most cases, is generally used. However, the temperature generated by the plasma or plasma arc acting on the front part of the anode results in evaporation of the anode material. This can lead on the one hand to degradation of the electrodes and on the other hand to an accumulation of evaporated material in the inner space of the discharge vessel, which can lead to a reduction in light and/or a reduction in the service life of the lamp.

Disclosure of Invention

The object of the invention is therefore: as good a heat removal (dissipation) as possible of the front electrode region in the vicinity of the discharge arc is ensured, wherein in particular the thermal conductivity of the electrode should be improved.

There are various solutions that should yield an improvement in the heat removal from the electrodes, i.e. heat dissipation from the electrodes. One possibility is to coat the anode with a material having an improved emissivity in the infrared range (e.g. Osram, DE 102009021235B 4). Microstructuring of the electrode surface is also used for the purpose of improving the thermal emission (Ushio, JP3838110B 2). All the mentioned means are used for heat emission from the electrode surface. Another solution aims at improving the thermal conductivity along the axis of the electrode. For this purpose, the electrode can have an inner section or core region which has a higher electrical conductivity than pure tungsten. One example is an anode with a hermetically closed inner space filled with a low melting metal, i.e. for example silver or copper (Ushio, EP 1357579B 1) or an alloy. Such anodes have been used for a long time in mercury discharge lamps. At the temperatures prevailing during operation, the low-melting metal enclosed in the interior space melts and can also partially convert into the gaseous state of aggregation. In the melting or evaporation process, thermal energy is absorbed from the low-melting metal and is additionally transported via a convection process from the region in front of the electrode towards the discharge arc to the region in back of the electrode towards the electrode rod.

Details of the discharge lamp construction are exemplarily shown in fig. 18, which schematically shows a gas discharge lamp 10 with electrodes 1 and 2. The gas discharge lamp 10, which is preferably designed as a high-pressure mercury gas discharge lamp, is a vertically operating discharge lamp 10, so that the electrode axes of the two electrodes 1 and 2, which extend parallel to one another, in particular extend in a straight line, are likewise aligned vertically. Furthermore, in the example described, the electrode 1 is configured as a cathode with a cathode tip 11 and a cylindrical region 12, while the electrode 2 represents an anode and has an anode platform 14 and a likewise cylindrical region 13. The anode 2 is arranged above the cathode 1 with the anode platform 14 facing the cathode tip 11, wherein, in operation, a discharge arc is formed between the anode platform 14 and the cathode tip 11. Furthermore, the two electrodes 1 and 2 are arranged in a discharge vessel 7, for example a glass bulb. In order to hold the electrodes in the discharge vessel 7, a cathode holding rod 3 and an anode holding rod 4 are provided. The holding rod is electrically connected to the connection sockets 8 and 9 via the internal current supply means 5 or 6, wherein the connection sockets 8, 9 can in turn be connected to an energy source via suitable external current supply means for operating the discharge lamp 10 (not shown).

The high-pressure gas discharge lamp 10 is preferably operated at high power, in particular in the kilowatt range. Thereby generating a very high temperature mainly at the anode 2. Typically, the temperature in the anode plateau region is about 2700 ℃ and drops to about 1500 ℃ to 1100 ℃ towards the anode holding rods, which depends to a large extent on the thermal conductivity and thermal emissivity of the anode. In any case, heat must be conducted away from the anode 2 as efficiently as possible to increase the useful life of the anode 12 or to achieve the desired current carrying capacity.

The object of the invention is therefore: an electrode for a gas discharge lamp with improved properties is proposed. On one hand, the method comprises the following steps: as good a heat dissipation as possible of the electrode is achieved, in particular of the front, electrode region in the vicinity of the discharge arc. In particular, the thermal conductivity of the electrodes should be improved.

This object is achieved by an electrode for a gas discharge lamp having the features according to claim 1. Advantageous embodiments of the invention are the subject matter of the dependent claims, the description and the figures.

As already mentioned at the outset, the invention also relates to a gas discharge lamp having at least one electrode according to the invention.

The invention described below is intended to increase the thermal conductivity in the interior of the anode, wherein the disadvantages of the single-chamber designs described above in the prior art should be overcome or at least reduced by means of the multi-chamber design. To this end, the anode/electrode has two or more chambers in the interior of its generally cylindrical base. In particular, the multi-chamber design should be designed such that a more intense directed convection is enabled for more efficient heat transfer. Furthermore, local heating should be avoided and greater flexibility in the location of the lamp burning should be achieved. Furthermore, the multi-chamber design enables higher stability in the critical plateau region of the electrode. Overall, the anode should have n chambers, where 2 ≦ n. Here, the following notation shall apply (see also fig. 1C and associated drawing description):

n-number of chambers

r_iShortest distance of chamber i to anode edge

s_iShortest distance of chamber i to the platform plane of the anode

d_iDiameter or maximum extension of the chamber parallel to the platform

a_ijMinimum distance between chamber i and chamber j

In one embodiment, the anode comprises a first anode part, a closure part or a lid, and a second anode part, a container part or a can (recess in the base body of the electrode), which are connected to one another in an air-tight or sealed manner. The chamber is located in the lower part of the anode (can). Some examples of the arrangement of two or more chambers are visible in fig. 3 to 9 (top view), wherein in these examples the chambers are arranged adjacently, so that the chambers or at least a part of the chambers are arranged parallel to one another in the longitudinal extension direction of the base body.

The multi-chamber design according to the invention has the advantage of a very high flexibility in design aspects, so that various ones of the above-mentioned aspects can be highlighted and preferably optimized depending on the specific application, for example depending on the lamp type (lamp filling, filling pressure, electrode diameter, electrode geometry, etc.), lamp power, lamp burning position and many other influencing variables.

In principle, in any case all parameters of the respective chamber can be adjusted individually and in principle independently of the other chambers. In addition to the pure geometric parameters, i.e. for example the markings detailed above, it is also possible to adjust the surface properties of the respective chamber inner wall. Furthermore, it is possible that: the filling of each chamber is set individually, for example with respect to the low-melting metal to be filled (material choice) or its filling height. Other optimization possibilities are the arrangement of the individual chambers relative to each other and relative to the outer wall of the electrode.

For example, the chambers can all have the same shape and the same depth in terms of geometry, which can be achieved particularly easily in terms of manufacture. However, the chambers can also have different shapes and/or depths from each other, depending on the application (see e.g. fig. 7, 12). Possible shapes can be distinguished, for example, by their cross-section, wherein round (for example circular or oval) and angular (for example triangular, quadrangular or polygonal) shapes can be used. In principle, however, mixed shapes are also conceivable in which a first cross section is present in the first portion and a second cross section, which is different from the first cross section, is present in the second portion. In other words, for example, the transition from a round cross section to an angular cross section or from a round cross section to an oval cross section can take place over the longitudinal extension of the chamber.

Suitable production methods, in particular for round chambers, are, for example, drilling, turning or milling. Other chamber shapes (angular, semi-circular, etc.) can be made, for example as so-called raw material anodes. In this case, the powder consisting of the carrier material (e.g. tungsten) and the binder can be formed almost arbitrarily, for example by means of a casting mold. The binder is then removed and the billet is again compacted.

In principle, with regard to the production method, a distinction must be made between methods in which the individual chambers are formed from the electrode base body by a chip-cutting process (and in which a container or pot-like recess is formed in the base body), and methods in which the individual chambers are produced outside the electrode base body and are introduced into the electrode base body in a temporally subsequent method step, wherein the base body must have a cavity of suitable dimensions for this purpose.

As mentioned above, the multi-chamber design has a high degree of flexibility in design, since substantially all geometric and non-geometric chamber characteristics can be individually adapted and the entire system can be optimized. In the following, exemplary embodiments are explained in detail for some of the described geometric and non-geometric chamber properties.

Length of the chamber:

in addition, each can be adjustedThe length of the individual chambers is such that the best possible compromise between heat removal and electrode stability is achieved, depending on the respective position of the chambers in the (usually cylindrical) base body of the electrode. For example, chambers in the vicinity of the axis of symmetry of the electrode base body can be formed shorter than chambers at greater distances from the axis of symmetry of the electrode base body (see fig. 12). Since particularly high temperatures occur near the plateau, in particular at the arc start near the axis of symmetry of the electrode base body, it is possible with this embodiment to optimize the distance s of the individual chambers i as a function of their position relative to the arc start_iIn order to thus prevent the risk of deformation, or even the risk of said area becoming unsealed.

Arrangement of the chambers:

the arrangement of the individual chambers i in the interior of the electrode is preferably designed symmetrically, in particular rotationally symmetrically, with respect to the longitudinal axis of the electrode. This has the advantage that: in practice, in the case of vertical combustion positions, which often occur, the heat flow can be distributed uniformly over the electrode cross section (for example, viewed in a plane perpendicular to the longitudinal axis of the electrode), in order to thus achieve effective heat removal from the electrode and in order to avoid local heating and damage. Conceivable arrangements are shown in fig. 3 to 6, 8 and 9.

In the case of a non-vertical combustion position, an asymmetrical, in particular non-rotationally symmetrical, arrangement of the chambers can contribute to the adjustment of the convection and heat flow with respect to the direction of gravity. For example, in one embodiment, a greater number of chambers are provided on the side closest to the bottom than on the opposite side of the electrode in the case of a lamp inclined away from the vertical (see fig. 7, where the right side of the electrode side shown in the figure in dashed lines is the side closest to the bottom).

In addition to the adjustment of the arrangement of the individual chambers, in the case of non-vertical combustion positions, other geometric and non-geometric properties, such as chamber geometry (diameter, length, shape), chamber filling (material, filling height), etc., can also be adapted.

Filling of the cavity:

in principle, each chamber can be filled independently of the other chambers. This relates to the type of material itself that is filled and its amount (volume or mass percent).

Suitable materials for the above-mentioned heat transfer are, in particular, low-melting metals (i.e. for example silver, copper, gold) and other metals known in principle from the prior art having a lower melting point and a higher thermal conductivity than tungsten. The material is typically filled into the chamber as a solid. In addition to the low-melting metal or in addition to the alloy consisting of the low-melting metal, a protective gas (e.g., an inert gas such as argon) can be enclosed in the respective chamber.

Furthermore, other materials can be enclosed into the respective chambers, which can further increase the thermal conductivity without melting under operating conditions. These other thermal conductors can be non-metallic materials, such as diamond or ceramic materials such as boron nitride, aluminum nitride. The additional thermal conductors are preferably introduced into the respective chambers in powder form. Details of this are disclosed in DE 102018220944.8.

Wall properties:

the properties s of the inner surface of each chamber are another influencing factor with regard to its thermal behavior. In terms of production, a smooth inner chamber wall with a surface roughness which is formed in the context of the above-described production process (for example a chip-removing process, such as drilling, turning or milling) is particularly simple. By means of alternative or additional manufacturing processes, roughening or structuring of the surface can be produced, for example by mechanical processes (e.g. sandblasting, sputtering, grinding, etc.), chemical processes (e.g. etching) or other physical processes (e.g. laser structuring, plasma etching, ion irradiation, etc.). The purpose of such surface treatment can be: the surface is structured such that a heat transfer in the form of a heat pipe (thermosiphon, heat pipe) can take place with improved back transport of the working medium (here a low-melting metal) from the heat release zone (anode holding rod) to the heat source (anode platform). The transmission back can take place purely passively and can be done by gravity and/or by other forces (for example capillary forces). For this purpose, a network structure, sintered structure, core structure, grooves or channels or a combination thereof provided at the inner surface of the chamber i can be suitable. A corresponding design is disclosed, for example, in DE102007038909a 1.

Number of chambers:

the optimum number of chambers depends in principle on various factors, among which are: the geometrical properties (e.g. diameter, length, shape, etc.) of each chamber i, the filling (material type, filling height, additional filling composition, etc.) of each chamber i, the wall properties of the chambers i and the arrangement of each chamber i relative to each other. In this case, the individual factors can influence one another. Thus, for example, the achievable packing density of the chambers i in the electrode base body depends on the diameter and shape of the individual chambers i. Furthermore, the ratio of chamber surface area to chamber volume can also have an effect when it comes to achieving an effective directed heat flow. In addition, the ratio of the chamber volume to the surrounding tungsten volume also has an effect on the current carrying capacity of the anode. As mentioned before, all these considerations also depend on the operating conditions of the lamp, in particular on its burning position.

Cross section of the chamber:

the traditional solution with only one chamber involves the risk of deformation of the platform. In the present invention, the deformation tendency can be reduced by: i.e. the chamber is chosen such that the projection of the cross-sectional area of the chamber onto the platform fills only a part of the platform (see e.g. fig. 15). Here, the area of the stage is A_pWherein A is_p＝π*p²And/4, wherein p is the diameter of the platform. The projection of the chamber cross-sectional area on the platform has an area A₁、A₂、A₃……A_nThus, the sum of the projected cross-sectional areas is A_S＝A₁+A₂……A_n. For an advantageous configuration of the chamber, 0.1 should be suitable<A_S/A_p<0.9, particularly advantageously 0.3<A_S/A_p<0.8. In the case of smaller values, heat can no longer be effectively conducted away through the material in the chamber. If the ratio is greater than 0.9, the risk of deformation of the platform increases and the drawbacks of the conventional solution emerge again.

Distance of chambers from each other:

the distance a between the chambers_ijCan be chosen small, wherein the lower limit is mainly determined by the risk of cracks forming during machining or operation. Therefore, it should be applied that_ij≥1mm。

Distance of chamber from platform and from edge:

distance s from chamber to anode platform_iIs influenced by two factors: on the one hand, the distance should be small in order to dissipate heat as efficiently as possible. On the other hand, the distance should be chosen large to avoid cracks or deformations in the platform. Now, the deformation tendency follows the diameter (or its maximum expansion) d of the chamber_iThe distance to the platform can also be reduced by increasing, i.e. by selecting a smaller diameter. Distance s_iIt should now advantageously be at least 3mm, or at least d_i3, i.e. s_i≥d_i(iii) 3 and s_iNot less than 2 mm. Chamber to edge distance r_iThe spacing from the platform should be chosen small, since the heat emission via the jacket of the anode also effectively contributes to the reduction of the temperature at the platform. The tendency to deform is even lower due to lower temperatures compared to the plateau and due to the absence of pressure caused by the plasma. Of course, cracks due to tension must be avoided, so that the following relationship should advantageously be observed: si is not less than d_i(ii) 4 and s_i≥2mm。

Alternatively or in addition to the above-described embodiments, it is also possible to arrange different chambers one after the other in the longitudinal extension direction of the electrode, so that the chambers or at least some of the chambers are arranged in series with one another in the longitudinal extension direction of the base body. Fig. 17B shows an example in which the anode has four chambers K1 to K4, which are arranged along the longitudinal extension a of the anode and thus form a stack-like arrangement. In this example, the chambers each have the same dimensions (length, width, depth) and have a rectangular cross-section. As already described in detail above, there are also wide variation possibilities for the embodiments in terms of the geometric and non-geometric properties of the chambers, which relate for example to their shape, their distance from each other, their distance to the anode edge (side walls, covers, anode lands), their filling, their wall properties, etc. In particular, the individual chambers i can have different geometric and non-geometric characteristics from each other, so that, for example, a chamber near the anode platform can have a different geometric size than a chamber further away from the anode platform.

In summary, it can thus be determined that: the overall design of the multi-chamber electrode is a function of a large number of parameters, some of which (not exhaustive) have been listed and explained above, wherein the individual parameters can be selected partly independently of one another, but can also be partly directly linked to one another.

Sealing:

various methods are contemplated for sealing the chamber.

a) One possible solution is: each individual chamber is closed with a plug of a material from which the lid (i.e. the closure part) and the can/container part (i.e. the recess in the electrode base body) are also made, preferably tungsten. Here, a plug is required for each filled chamber (see e.g. fig. 13). For example, the plug is designed such that it is circumferentially provided with a groove. The portion above the slot is designed to be wider to prevent "slipping" into the opening of the chamber. The groove now accommodates a spiral of material acting as solder. The individual chambers are sealed by heating the solder, for example in an oven. The solder material must be chosen such that it does not liquefy again in subsequent operations. Suitable examples of anodes in mercury discharge lamps are molybdenum/ruthenium, titanium/tungsten, zirconium/tungsten or platinum/tungsten. The temperature is adjusted according to the respective field of application.

b) In a variant of a), the solder is not introduced in the form of a spiral, but rather as a metal foil which is wound around the plug and pressed with the plug into the cavity. Here, the plug shape appears to be cylindrical, but alternatively conical. Sealing is effected as under a) by a thermal step (e.g. furnace annealing).

c) A third possibility is to apply solder to the end face of the can so that all chambers are separated from each other after the soldering process, but are closed to some extent by the same plug (here the end face of the can). Embodiments can be considered in which the solder is introduced spherically into the recess, see for example fig. 14. The dashed lines here show the recesses into which the solder in the form of pellets is filled.

d) Another possibility consists in: the plug and the corresponding chamber are provided with threads so that the plug can be screwed into the chamber. Furthermore, the plug can also be sealed with solder.

The conventional variant with one chamber has the following disadvantages: deformation of the platform occurs due to the strong thermal load. Under corresponding loading, the resulting recess in the plateau region can become so large that the material is no longer mechanically resistant and the filling material (for example copper or silver) leaves the anode, which leads to failure of the lamp. Therefore, it is necessary to ensure that: the distance s between the borehole and the platform is sufficiently large. On the other hand, the distance should be small again in order to achieve as good a heat dissipation as possible.

By means of a multi-chamber system, the chamber-to-platform distance s can be set_iChosen to be small without causing such deformation and possible failure of the lamp.

Drawings

Further advantages, features and details of the invention emerge from the following description of preferred embodiments and from the drawings. For the sake of simplicity, identical or identical types of features can also be denoted by identical reference numerals in the following.

Shown here are:

FIG. 1A schematically illustrates a top view of an anode according to one embodiment of the present invention;

FIG. 1B schematically shows a cross-sectional view of the anode in FIG. 1A;

FIG. 1C schematically illustrates a partial cross-sectional view of the anode of FIG. 1A;

figure 2A schematically shows a top view of an anode according to a second embodiment of the invention;

FIG. 2B schematically shows a longitudinal cross-sectional view of the anode in FIG. 2A;

FIG. 2C schematically illustrates a cross-sectional view of the anode in FIG. 2A;

3-9 respectively schematically illustrate cross-sectional views of anodes according to seven further embodiments of the invention;

FIG. 10 schematically illustrates a partial cross-sectional view of an anode having anode grooves according to one embodiment of the invention;

FIG. 11 schematically illustrates a partial cross-sectional view of an anode having anode grooves according to another embodiment of the invention;

FIG. 12 schematically illustrates a cross-sectional view of an anode having chambers of different lengths according to one embodiment of the invention;

FIG. 13 schematically shows a cross-sectional view of an anode with a separate plug and an additional cover in a chamber according to another embodiment of the invention;

FIG. 14 schematically illustrates a top view of an end face of an anode having three chambers, according to one embodiment of the invention;

FIGS. 15 and 16 each schematically show the projection of a cross-section of three chambers onto a respective anode platform;

17A, 17B schematically show a top view or a longitudinal cross-section, respectively, of an anode according to another embodiment of the invention;

fig. 18 schematically shows a top view of a gas discharge lamp according to an embodiment of the invention.

Detailed Description

Fig. 1A and 1B schematically show a top view or a cross-sectional view, respectively, along the longitudinal axis a of an anode 2 according to a first embodiment of the invention. The anode 2 is composed of a cylindrical container member 22, a can and closure member 24, and a lid. The can 22 has an anode platform 14 and a plurality of chambers, here two chambers 221, 222, which are configured as recesses in the base body of the can 22. The two tubular chambers 221 and 222 are partially filled with silver 26 (shown as the dashed areas). The end of the can 22 opposite the anode platform 14 is closed with a cover 24. Here, the cover 24 also closes the open ends of the two chambers 221, 222 opposite the anode platform 14 at the same time. The cover 24 has a bore 241 for an anode holder (not shown here).

In the figure1C, the schematic partial section of the anode 2 according to fig. 1A shows the initially introduced marking in some geometrical dimensions. Thus, L represents the length of the anode 2 from the anode platform 14 to the opposite interface side end of the cover 24, D represents the diameter of the anode 2, D_iDenotes the maximum expansion or diameter of the ith chamber parallel to the anode platform 14 (i-1 to n; in this example n-2), r_iRepresents the shortest distance, s, of the chamber i to the edge of the anode 2_iRepresents the shortest distance, a, of the chamber i to the flat surface 14 of the anode 2_ijRepresents the minimum distance between chamber i and chamber j (in this embodiment the minimum distance a between the two chambers 221 and 222)₁₂)。

Fig. 2A shows a top view and fig. 2B and 2C schematically show a longitudinal or cross-sectional view of an anode 20 according to a second embodiment of the present invention. Here, the canister 22 of the anode 20 has five chambers 221-225, which each have a circular cross section and are each individually closed with an associated plug 261-265 (only two plugs 261 and 262 are shown in fig. 2B).

Fig. 3 to 9 each schematically show a cross-section of an anode (similar to fig. 2c) according to seven further embodiments of the invention. The anodes of the described embodiments differ in the number and/or shape and/or diameter of the chambers. To make the chamber more easily visible, the cross-section passes through the silver-filled portion, where the silver is represented as a dashed area as in fig. 1B. Fig. 3 shows an anode can 22 with five chambers 221-225, similar to what has been shown in fig. 2C. FIG. 4 shows an anode canister 22 having six chambers 221-226, wherein the chamber 226 at the center of the axis has a smaller diameter than the remaining five chambers 221-225. Fig. 5 shows an anode can 22 with seven chambers 221-227, all of the same diameter. Fig. 6 shows an anode can 22 having only three chambers 221-223. The respective diameters of the three chambers 221-. Figure 7 shows an anode can 22 also having three chambers 221-223. Here, of course, the chamber 221 is designed to have an elliptical diameter adapted to the curvature of the anode can 22. Instead, the other two chambers 222 and 223 have a circular cross-section, as in the previous embodiment. In the anode can 22 shown in fig. 8, two chambers 221, 222 are provided, which are formed with a mutually complementary semi-circular cross section. Finally, fig. 9 shows an anode can 22 with three chambers 221, 222 and 223, which are constructed as separate complementary parts of a cylindrical arrangement with a combined circular cross section.

Figures 10 and 11 schematically show partial cross-sectional views of anodes 2' and 2 ", respectively, according to two further embodiments of the invention. These are specific anode designs in which so-called anode grooves have been provided in the anode platform during the manufacturing process. In a corresponding cross-sectional view, in the embodiment of fig. 10 the anode grooves 14' have an angular shape, in the embodiment of fig. 11 the anode grooves 14 "have a circular shape.

Fig. 12 schematically shows a longitudinal cross-sectional view of an anode 20 according to another embodiment of the invention. The two chambers 221, 222 have the same diameter d_1,2And the same shortest distance s to the anode platform plane 14_1,2. Conversely, the third chamber 223, which is arranged in the longitudinal axis of the anode 20, has a larger diameter d₃And a longer spacing s from the anode platform plane 14₃。

Fig. 13 schematically shows a cross-sectional view of an anode 200 according to a variant, wherein the chamber 221 is closed with an associated separate plug 266. To seal the plug 266, a solder wire spiral 2661 is provided that is wound circumferentially around the plug 266. Finally, the can 22 of the anode 200 is closed with a lid 24, which also covers the plug 266 of the chamber 221.

Fig. 14 schematically shows a top view of an anode canister 220 with three chambers 221-223. The end face of the anode can 220 is shown, onto which the anode cap is slipped for closing and is connected by means of welding (the welding connection is not shown here). The dashed line 230 here represents a depression in the base body of the anode can 220, into which the solder is filled in the form of pellets (the pellets are not shown here).

Fig. 15 and 16 schematically show the projection planes a1, a2, A3 of the cross-sections of the three chambers (not shown) onto the respective anode platforms 14, respectively. As can be seen by comparing fig. 15 and 16: in both cases, the shapes of the projection planes a1, a2, A3 are also different depending on the chamber shape. In both cases, however, it can be seen that the sum of the projection planes a1, a2, A3 is smaller than the area of the anode platform 14, in each case by a factor of less than 0.9.

Fig. 17A and 17B schematically show a top view or a longitudinal cross-sectional view along the longitudinal axis a of an anode 202 according to another embodiment of the invention. Four chambers K1-K4 are arranged in succession in the direction of the longitudinal axis a in the anode can 22.

Fig. 18 schematically shows a top view of a gas discharge lamp 10 according to an embodiment of the invention. Here, the anode 2 corresponds to one of the embodiments according to the present invention shown in fig. 1 to 17. Details of the anode 2 not visible here may refer to corresponding paragraphs in the description and general description of the related figures. For other constructions of the gas discharge lamp 10 reference is made to the corresponding description above.

The invention relates to an electrode, in particular an anode, for a gas discharge lamp, wherein the electrode has a base body which surrounds a plurality of chambers. The chambers can be arranged parallel or in series with one another with respect to the longitudinal axis of the electrode and are at least partially filled with a low-melting metal, i.e. for example silver or copper. By appropriately matching the number, filling, shape and geometry of the individual chambers and their position within the substrate to the respective design of the electrodes, the heat dissipation of the substrate, in particular of the region near the anode platform, can be improved.

List of reference numerals

1 electrode (cathode)

2. 2', 2' electrode (Anode)

3 cathode holding rod

4 anode holding rod

5 internal Current supply device (cathode)

6 internal current supply device (Anode)

7 discharge vessel

8. 9 connection socket

10 discharge lamp

11 cathode tip

12 cylindrical region (cathode)

13 cylindrical area (Anode)

14 anode platform

14', 14' anode groove

20 electrode (Anode)

200 electrode (Anode)

202 electrode (Anode)

22 anode can

220 anode can

221-227 chamber

230 concave part

24 cover

241 drilling a hole

26 silver

261-

2661 solder wire spiral