GAS DISCHARGE LAMP, MORE PARTICULARLY DEUTERIUM LAMP

Abstract

An electrode insert that has: (a) an intermediate wall made of an electrically insulating material, (b) a cathode-side assembly which is mounted on a front side of the intermediate wall and comprises a cathode, a cathode window and a light emission window, (c) an anode-side assembly which is mounted on a rear side of the intermediate wall and comprises an anode and at least one diaphragm, which together with the light emission window defines an optical axis along which a beam generated by discharge is emitted out of the light emission window, wherein at least the anode and the diaphragm are grouped to form a component ensemble, and wherein at least one retaining profile for retaining the component ensemble projects from the rear of the intermediate wall.

Claims

1. Gas discharge lamp, in particular deuterium lamp, having a gas-filled lamp bulb which surrounds an electrode insert, wherein the electrode insert comprises: (a) a partition wall made of an electrically insulating material, (b) a cathode-side assembly mounted on a front side of the partition wall and comprising a cathode, a cathode window and a light emission window, (c) an anode-side assembly mounted on a rear side of the partition wall, comprising an anode and at least one diaphragm, which with the light emission window defines an optical axis along which a radiation generated by discharge is emitted from the light emission window, wherein at least the anode and the at least one diaphragm are combined to form a component ensemble, and wherein at least one retaining profile for retaining the component ensemble projects from the rear side of the partition wall.

2. Gas discharge lamp according to claim 1, wherein the component ensemble is designed as a component stack.

3. Gas discharge lamp according to claim 1, wherein the component ensemble comprises at least two diaphragms.

4. Gas discharge lamp according to claim 3, wherein at least one of the diaphragms, preferably the foremost diaphragm, has a contact to an electrical connection pin.

5. Gas discharge lamp according to claim 2, wherein the component stack has a stack height and a stack circumference, wherein the retaining profile at least partially encloses the stack circumference over the stack height.

6. Gas discharge lamp according to claim 2, wherein the component stack comprises a spring element which is designed to press the component stack against the partition wall.

7. Gas discharge lamp according to claim 2, wherein the component stack comprises insulating elements and at least one spacing compensation element.

8. Gas discharge lamp according to claim 1, wherein the retaining profile comprises at least two tube-shell-shaped profile parts which are arranged around the optical axis with their open sides opposite one another.

9. Gas discharge lamp according to claim 1, wherein the at least one diaphragm has integral spring elements.

10. Gas discharge lamp according to claim 9, wherein the at least one diaphragm is designed as a diaphragm disk, and in that the integral spring elements are designed as flexible brackets created by peripheral disk-edge incisions on opposite sides of the diaphragm disk.

11. Gas discharge lamp according to claim 9, wherein the integral spring elements are supported on the retaining profile.

12. Gas discharge lamp according to claim 1, wherein the partition wall and the retaining profile are designed as one piece.

13. Gas discharge lamp according to claim 1, wherein a mounting plate is arranged on the rear side of the partition wall, said mounting plate being provided with through-holes through which electrical connections are guided to the anode-side assembly.

14. Gas discharge lamp according to claim 13, wherein retaining rods for mounting the electrode insert in the lamp bulb engage in the mounting plate.

15. Gas discharge lamp according to claim 13, wherein the mounting plate is connected to a hollow mounting base which in the installed state extends in the direction of a lamp foot of the gas discharge lamp.

16. Gas discharge lamp according to claim 13, wherein the partition wall, the mounting plate and the mounting base are designed as one piece.

17. Gas discharge lamp according to claim 2, wherein the anode-side assembly comprises an anode housing which surrounds the retaining profile and a component stack retained thereon, and in that the cathode-side assembly comprises a cathode housing for receiving the cathode.

18. Gas discharge lamp according to claim 17, wherein the cathode housing is composed of a plurality of molded parts which are connected to one another by means of a plug-in connection, in particular an interlocking connection.

19. Gas discharge lamp according to claim 17, wherein the cathode housing has bendable insertion tabs which correspond to longitudinal slots in the partition wall.

20. Gas discharge lamp according to claim 1, wherein the partition wall consists of ceramic, in particular of aluminum oxide ceramic.

21. Gas discharge lamp according to claim 1, wherein it comprises a glass foot plate mounted in the lamp bulb, on which a plurality of retaining rods and a plurality of electrical connection pins are mounted, wherein the foot plate, the retaining rods and the connection pins form a prefabricated assembly which is electrically and mechanically connected to the electrode insert.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0051] The invention is explained in more detail below with reference to an exemplary embodiment and a patent drawing. The following are shown in detail:

[0052] FIG. 1 an embodiment of an electrode insert for a deuterium lamp, based on an exploded view,

[0053] FIG. 2 an embodiment of a cathode-side housing for the electrode insert of FIG. 1, in an exploded view,

[0054] FIG. 3 the cathode-side housing of FIG. 2 in an assembly drawing

[0055] FIG. 4 a plurality of views of the electrode insert of FIG. 1,

[0056] FIG. 5 a photograph of a ceramic partition wall for an electrode insert in a plan view of the retaining profile with inserted foremost diaphragm,

[0057] FIG. 6 an alternative embodiment of a partition wall for an electrode insert in a three-dimensional representation,

[0058] FIG. 7 a photograph of an electrode insert similar to that of FIG. 1 with a ceramic partition wall with a break-out of the retaining profile in order to demonstrate the component stack located therein

[0059] FIG. 8 a photograph of the electrode insert of FIG. 7 in assembly with retaining rods and electrical connection pins and a glass plate (as foot of a deuterium lamp) and also other individual parts of the electrode insert,

[0060] FIG. 9 a photograph with two variants of a housing for the anode-side assembly,

[0061] FIG. 10 a schematic sketch of a gas discharge lamp according to the invention in a view of the rear side, and

[0062] FIG. 11 a disk-shaped diaphragm with lateral spring elements and a receiving socket for an electrical connection pin in a plan view.

[0063] The directional cross drawn above the exploded view of the electrode insert according to FIG. 1 serves to illustrate positional or orientational information used in the following description of the electrode insert.

[0064] The central component of the electrode insert 1 is a ceramic partition wall 2 serving as a carrier assembly for a plurality of components. From the rear side 21 of the ceramic partition wall 2, two structurally identical, substantially cylindrical, and in plan view C-shaped retainers 3 project vertically, which are face one another with their open C-sides and which are also referred to below as “C-towers” 3. The C-towers 3 define an essentially cylindrical intermediate space extending coaxially with the optical axis 11. This serves to receive and retain a stack of a plurality of components arranged one after the other, which overall is assigned the reference number 4, and which is also referred to below as a “diaphragm stack”. In the exemplary embodiment, the substantially cylindrical intermediate space has an almost circular cross-section with a minimum inner diameter of 8 mm.

[0065] A plurality of diaphragms are combined in the diaphragm stack 4; in the exemplary embodiment, there are three diaphragms 51, 52, 53 made of molybdenum, which are separated and electrically insulated from one another by spacer rings 61, 62 made of ceramic. Adjoining to the rear is an anode 7, bounded on both sides by ceramic disks 81, 82, with central hole 7a and connection tabs 7b. The diaphragm stack 4 is outwardly completed by a spring washer 9. For fastening the diaphragm stack 4 between the C-towers 3, a retaining bracket 10 made of molybdenum is used, which is guided through holes 10a in the C-towers 3. It serves as an abutment for the spring washer 9, which by its spring force presses the diaphragm stack 4 forwards in the direction of the ceramic partition wall rear side 21. The spacer rings 61, 62 and the ceramic disks 81, 82 are circular and have a diameter of 7.9 mm. Any regions of the other components 51, 52, 53, 7, 9 projecting beyond the circular shape extend through a free gap between the two C-towers 3, thus likewise fitting into the intermediate space; they are used to support the alignment of the components during assembly and contribute to protecting against rotation.

[0066] The diaphragms 51, 52, 53 each have a diaphragm hole 51a, 52a, 53a with a diameter of 0.3 mm, wherein the center points of the diaphragm holes 51a, 52a, 53a lie on the optical axis 11. The foremost diaphragm 51 is also provided with contact legs 51c for receiving an electrical connection pin (26), via which an additional auxiliary ignition pulse can be applied to the foremost diaphragm 51. Otherwise, it is the task of the diaphragms 51, 52, 53 to constrict the plasma of the deuterium lamp and thus to produce a plasma with high local radiance, said plasma being precisely localized.

[0067] The diaphragms 51, 52, 53 each have two elastically resilient, integral brackets, which are produced by a lateral peripheral incision in the diaphragm edge, and which are referred to below as “spring legs” 51b, 52b, 53b. In the installed state, the spring legs 51b, 52b, 53b exert a force directed in the direction perpendicular to the optical axis 11 onto the diaphragms 51, 52, 53 and press them against two contact beads 31 in the upper half of the C-towers 3. The two spring legs 51b, 52b, 53b support themselves against two other contact beads 32 in the lower half of the C-towers 3, so that all diaphragms 51, 52, 53 are retained between the C-towers 3 with a total of four contact points (four-point mounting). The two contact beads 31 in the upper half of the C-towers 3 lie on the same radius starting from the optical axis 10. This ensures a centering of all diaphragms 51, 52, 53 of the diaphragm stack 4 on the optical axis 11 of the deuterium lamp without further aids, which is important for an optimal radiance of the deuterium lamp.

[0068] The diaphragms 51, 52, 53 of the diaphragm stack 4 aligned on the optical axis 11 of the deuterium lamp form a channel on the projection of the optical axis 11, the diameter of which channel corresponds to that of the individual diaphragm holes 51a, 52a, 53a. The disadvantage of a correspondingly long individual channel in relation to ignition behavior is avoided by the separation of the diaphragms 51, 52, 53 by means of the ceramic spacer rings 61, 62.

[0069] The diaphragms have thicknesses in the range of 0.1 to 1 mm; in the exemplary embodiment it is 0.5 mm. The ceramic spacer rings 61, 62 determine the diaphragm spacing and have thicknesses in the range of 0.1 to 1 mm; in the exemplary embodiment, it is 0.25 mm. The front ceramic disk 81 is arranged behind the last diaphragm 53 and has a thickness in the range of 0.1 to 1 mm, in the exemplary embodiment it is 0.8 mm. The thickness of the rear ceramic disk 82 is designed such that a total length of 4 mm results for the diaphragm stack 4 (without spring washer 9 and retaining bracket 10). An electrical connection pin 26 (anode pin) is welded to the anode pin of the lamp foot at the connection tabs 7b of the anode 7.

[0070] During operation, the deuterium lamp heats up to an operating temperature above room temperature. The thickness of the spring washer 9 at 0.2 mm and its bending radius at 6 mm are designed such that, on the one hand, the components in the component stack 4 cannot slip and that, on the other hand, the thermal expansion of the component stack 4 can be compensated during operation of the deuterium lamp. Despite the absence of play, the spring-loaded mounting of the diaphragms 51, 52, 53 also enables a compensation for the different thermal expansions of ceramic (of the spacer disks and insulating disks) and molybdenum (of the diaphragms). The choice of molybdenum as the diaphragm material ensures a spring property over the entire temperature range.

[0071] Thickness and number of diaphragms and the diaphragm opening diameter influence the ignition behavior, the arc voltage and the radiance of the deuterium lamp. With increasing number and thickness of the diaphragms and decreasing diameter of the diaphragm opening, ignition of the lamp becomes more difficult and the arc voltage rises. The total length of the diaphragm channel is predetermined by the diaphragms 51, 52, 53 including the spacer disks 61, 62. For a defined total length of the diaphragm channel, it has proven to be more advantageous to use a plurality of thin diaphragms than a few thick diaphragms. In this case, ignition takes place more reliably and the arc voltage is lower. This was demonstrated in tests. The hole diameter of the diaphragms is usually less than 0.5 mm (in the exemplary embodiment it is 0.3 mm); a diaphragm thickness of 0.5 mm, a diaphragm spacing of 0.25 mm (thickness of the spacer disks 61, 62) and a diaphragm number of 3 result in a total channel length of 2.00 mm.

[0072] For plasma guidance, both the diaphragm stack 4 on the rear side 21 and the cathode on the front side 22 of the ceramic partition wall 2 are each enclosed by a housing 100, 200.

[0073] Insofar as the same reference numbers are used in FIGS. 2 to 11 and in the description of the figures, as in FIG. 1, they denote the same components or equivalent components of the gas discharge lamp.

[0074] FIG. 2 shows the front assembly 200 which is mounted on the front side of the ceramic partition wall 2 and surrounds the cathode chamber. This is composed of a metal front 201 with a light emission window 201a which corresponds to an opening (reference number 2a in FIG. 4(c)) of the ceramic partition wall 3, a metal intermediate plate 203 with cathode window 203b, a metallic top plate 204 and a ceramic bottom plate 202. For assembly, the metal intermediate plate 203, the top plate 204 and the ceramic bottom plate 202 are inserted with tabs (202a, 203a, 204a) into corresponding slots 201b in the metal front 201. FIG. 3 shows the metal front assembly 200 when assembled. In addition, the position of the wound cathode 205 is indicated.

[0075] The metal front 201 is curved in a U-shape and has two rearwardly pointing tabs 201c, by means of which it is fastened to the front side 22 of the ceramic partition wall 2. Here, the two tabs 201c are inserted through two corresponding slots (reference numeral 2b in FIG. 4(a)) in the ceramic partition wall 2 and then bent over. This achieves a play-free mounting of the metal front assembly 200 on the partition wall 2. Alternative technologies such as riveting or welding are more complex. Welding also has the disadvantage that the heating of the materials leaves oxidation traces which can have a disadvantageous effect on the operation of the deuterium lamp.

[0076] On the rear side 21 of the partition wall 2, the diaphragm stack 4 together with the anode 7 is enclosed by an anode housing 100, the rear wall 101 of which has a hole 102 on the optical axis 11 and enables a combined use of the deuterium lamp according to the invention with an incandescent lamp. In this case, the light of the incandescent lamp radiates through the deuterium lamp (shine-through operation) in order to produce a combined UV/VIS spectrum. The anode housing 100 reduces secondary discharges, i.e. discharges which do not lead through the channel of the diaphragm stack 4. The anode housing 100 can be made of metal or ceramic. Preferably, it consists of metal in order to keep the weight and the costs of the deuterium lamp low.

[0077] For fastening to the partition wall 2, the anode housing 100 is provided with two laterally protruding wings 103, in each of which a longitudinal slot 103a extends from top to bottom. For fastening, the tabs 201c of the front assembly 200 are also inserted through these longitudinal slots 103a.

[0078] The design principle of inserting tabs through slots and then fastening them by bending enables a play-free mounting of the entire housing structure in a simple and cost-effective manner.

[0079] Integral components of the ceramic partition wall 2 are a mounting plate 23 pointing at right angles to the rear and a mounting base 24. For mounting the ceramic partition wall 2 on a foot plate 181 (shown in FIG. 8), three retaining pins 25 made of metal are provided, which extend along the mounting base 24 and whose ends extend on one side through through-holes (reference numeral 23a in FIG. 4 (d)) in the mounting plate 23 and on the other side through through-holes in the foot plate 181. Via the three retaining pins 25, the ceramic partition wall 2 is thus mounted on the foot plate 181 of the deuterium lamp at three support points.

[0080] For fastening, the free ends of the retaining pins 25 are crimped, welded, pinched or bent over. In particular by bending over above the mounting plate 23, a play-free mounting of the ceramic partition wall 2 against the lower support points on the foot plate 181 can be realized. This is important for the exact localization of the plasma in lamp operation.

[0081] In an alternative embodiment, the retaining pins 25 are pinched on the underside of the mounting plate 23 in order to produce support points here which define the height of the ceramic partition wall 3 above the foot plate 181. The support points are located on the retaining pins 25 directly below the mounting plate 23. They can either be crimped as sleeves onto the retaining pins or the retaining pins 25 themselves are pinched so that material projects beyond the actual diameter of the retaining pins 25, which serves as a bearing surface.

[0082] In a further alternative embodiment, the retaining pins 25 are not bent over on one side above the mounting plate 23, but are slit in the center and the slitted ends are bent symmetrically in two directions.

[0083] Further through-holes of the mounting plate 23 serve for the electrical contacting of the electrodes (anode, auxiliary anode and cathode (with two terminals)). For this purpose, electrical connection pins 26 extend on the one hand through the through-holes of the mounting plate 23 to the corresponding electrodes, and on the other hand right through through-holes of the foot plate to electrical connection elements of the deuterium lamp.

[0084] Further details can be seen from the views of the electrode insert 1 in FIG. 4, such as the slots 2b in the ceramic partition wall 2 in the front view of FIG. 4(a) and in the rear view of FIG. 4(c). As well as the through-holes 23a of the mounting plate in the plan view of FIG. 4(d). FIG. 4(b) shows a side view of the electrode insert 1 and FIG. 4(e) an assembly.

[0085] From the plan view of the retaining profile 3 with the foremost diaphragm 51 inserted therein according to FIG. 5 the two lateral spring legs 51b and the kerf 51d for their production are clearly visible. To ensure the four-point mounting of the diaphragm 51, the spring legs 51b rest against the two lower contact points 32 of the C-towers 3 and press the diaphragm 51 against the two upper contact points 31. The photograph shows a variant of a ceramic intermediate plate 2, which for the assembly of anode housing and cathode housing is provided laterally with double slots 2d for the insertion of corresponding connection tabs.

[0086] FIG. 6 shows an embodiment of a partition wall 62 for an electrode insert with an alternative retaining profile and the diaphragm stack 4 mounted therein. The alternative retaining profile is formed from two structurally identical cylindrical profiles 63 which project perpendicularly from the rear side 62a of the partition wall 62. In cross-section, the profiles 63 are essentially rectangular, each having an indented longitudinal side, which face one another and define the receiving space for the diaphragm stack 4.

[0087] The photograph of FIG. 7 shows an electrode insert 71 with a ceramic partition wall 72 with a cutout 182 in the region of one of the retaining profiles 3. The cutout 182 makes the diaphragm stack 4 and its fastening by means of the spring washer 9 and the retaining bracket 10 visible. The construction of the electrode insert 71 essentially corresponds to that of the electrode insert 1 of FIG. 1.

[0088] The photograph of FIG. 8 shows once (a) the foot plate 181 in the connection to the mounting plate 23 of the electrode insert 71 of FIG. 7 (with the additional cutout 182). And it shows another time (b) the foot plate 181 in connection with only the retaining rods 25 and the connection pins 26. The foot plate 181 can consist of soft glass or quartz glass. In the case of soft glass, the connection pins 26 preferably consist of an iron-nickel-cobalt alloys with a coefficient of thermal expansion matched to the coefficient of thermal expansion of soft glass, and in the case of quartz glass, the connection pins 26 preferably consist of molybdenum. The ensemble of the components foot plate 181, retaining rods 25 and connection pins 26 is preferably a prefabricated assembly which, during the further processing to form the gas discharge lamp, only has to be electrically and mechanically connected to the electrode insert 71.

[0089] The part (c) is a housing 700 for the anode-side assembly, and the part (d) is a housing 800 for the cathode-side assembly. For the purpose of mounting on the ceramic partition wall 72, the housing 700 is provided with a double slot 701, and the housing 800 is provided with a double tab 801. For this purpose, the ceramic partition wall 72 likewise has a suitable double slot 72a.

[0090] FIG. 9 shows a photograph with two alternative embodiments of the housing for the anode-side assembly. The housing (a) consists of Al.sub.2O.sub.3 ceramic. The housing (b) consists of nickel. The rear wall in each case has a hole 702 which enables a combined use of the deuterium lamp with an incandescent lamp.

[0091] The sketch of FIG. 10 schematically shows a gas discharge lamp 1000 according to the invention in a rear view. The gas discharge lamp 1000 comprises a lamp bulb 1001 made of quartz glass mounted in a ceramic base 1002 and which contains a filler gas in the form of pure deuterium and encloses an electrode insert 1, as explained with reference to FIG. 1. The electrode insert 1 comprises a ceramic partition wall 2, on which a plurality of components are mounted, including a cathode housing 200 with the light emission window 201a. The lamp bulb 1002 is equipped with a flat foot plate 181. The mounting of a retaining rod 25 on the foot plate 181 by means of a crimp connection 181a made on both sides of the foot plate 181 (representing all further retaining rods 25 explained with reference to FIG. 1) is shown schematically. Likewise, the guiding of a connection pin 26 through a pinch 181b in the foot plate 181.

[0092] FIG. 11 schematically shows the disk-shaped diaphragm 51 of FIG. 1 in an enlarged view and in a plan view of a planar side. The diaphragm 51 has a diaphragm hole 51a and on the two sides two elastically resilient brackets 51b. These are integral components of the diaphragm 51. They are produced by an incision into the diaphragm material, which starting from the edge extends essentially peripherally along the edge over a circumferential angle of approximately 45 degrees. In the installed state, the spring legs 51b produced in this way rest on two upper contact points and on two lower contact points of the retainer 3, which are indicated in FIG. 11 by the reference numerals 51d.