LOW-PRESSURE MERCURY VAPOUR DISCHARGE LAMP AND LAMP SYSTEM

Abstract

The invention relates to a low-pressure mercury vapour discharge lamp comprising a discharge vessel which encloses a discharge chamber in a gas-tight manner with said discharge chamber being provided with a filling of mercury and a filler gas, in particular a noble gas, wherein the discharge vessel has a first end section and a second end section , a first electrode arranged on the first end section and a second electrode arranged on the second end section for maintaining a discharge along a discharge path between the first electrode and the second electrode , and an amalgam deposit for regulating the mercury vapour pressure in the discharge chamber is arranged on the first end section outside the discharge path , wherein the position of the amalgam deposit is secured by means of an adhesion agent .

Claims

1. A low-pressure mercury vapor discharge lamp comprising a discharge vessel which encloses a discharge chamber in a gas-tight manner with said discharge chamber being provided with a filling of mercury and a filler gas, in particular a noble gas, wherein the discharge vessel has a first end section and a second end section, a first electrode arranged on the first end section and a second electrode arranged on the second end section for maintaining a discharge along a discharge path between the first electrode and the second electrode, wherein an amalgam deposit for regulating the mercury vapor pressure in the discharge chamber is arranged on the first end section outside the discharge path, wherein the position of the amalgam deposit is secured by means of an adhesion agent.

2. The low-pressure mercury vapor discharge lamp according to claim 1, wherein the first electrode comprises at least one contact wire which extends from the first electrode in the discharge chamber to outside the discharge vessel,wherein the contact wire comprises a dielectric sheathing at least in sections within the discharge chamber, wherein the adhesion agent is arranged on the sheathing.

3. The low-pressure mercury vapor discharge lamp according to claim 2, wherein the sheathing is formed from, preferably consists of, quartz glass, in particular from the same material as the discharge vessel and/or wherein the sheathing sealingly encloses the contact wire (24).

4. The low-pressure mercury vapor discharge lamp according to claim 2 , wherein the sheathing extends in the form of a tape into the discharge chamber, wherein in particular the tape-shaped sheathing has a substantially rectangular cross section.

5. The low-pressure mercury vapor discharge lamp according to claim 2, wherein the adhesion agent on a lateral surface of the sheathing and/or an end face of the sheathing facing the first electrode is free of an adhesion agent.

6. The low-pressure mercury vapor discharge lamp according to claim 2, wherein the sheathing is fastened, in particular welded-on, in the first end section of the discharge vessel (6).

7. The low-pressure mercury vapor discharge lamp according to claim 1, wherein at least one heat shield arranged between the first electrode and the first end section, wherein the adhesion agent is arranged relative to the heat shield with respect to the first electrode.

8. The low pressure mercury vapor discharge lamp according to claim 7, wherein the heat shield comprises a coating reflecting infrared light.

9. The low-pressure mercury vapor discharge lamp according to claim 2,wherein the heat shield is formed by the sheathing (3) and/or wherein the heat shield is formed from a dielectric material, in particular from transparent quartz glass and/or amorphous quartz glass, preferably a semiconductor-doped amorphous quartz glass.

10. The low-pressure mercury vapor discharge lamp according to claim 1, wherein the adhesion agent is arranged on an inner side of the discharge vessel.

11. The low-pressure mercury vapor discharge lamp according to claim 1, low-pressure mercury vapor discharge lamp, wherein the amalgam deposit is equipped with an electromagnetic receiver for converting electromagnetic input signals into heat.

12. The low-pressure mercury vapor discharge lamp according to claim 11, wherein the receiver comprises the adhesion agent and/or the amalgam deposit or in that the receiver is formed separately from the amalgam deposit.

13. The low-pressure mercury vapor discharge lamp according to claim 1, further comprising a sleeve that reflects infrared light, which sleeve at least partially surrounds the amalgam deposit .

14. The low pressure mercury vapor discharge lamp according to claim 1, comprising a layer of a material that reflects infrared light arranged on the inner and/or outer side of the first end section of the discharge vessel.

15. A lamp system with athe low-pressure mercury vapor discharge lamp according to claim 1 and with an electromagnetic transmitter for exciting the electromagnetic receiver (7), wherein in particular the electromagnetic transmitter and the electromagnetic receiver are coordinated with one another such that the transmitter transmits, in particular inductively and/or capacitively, a heating current to the receiver for controlling the temperature of the amalgam deposit.

Description

[0036] Preferred embodiments of the invention are specified in the claims. Particular embodiments and aspects of the invention are described below with reference to the accompanying figures, in which are shown:

[0037] FIG. 1 an inventive lamp system with a low-pressure mercury vapor discharge lamp according to the invention according to a first embodiment;

[0038] FIG. 2 a low-pressure mercury vapor discharge lamp according to a second embodiment;

[0039] FIG. 3a a detailed view of the low-pressure mercury lamp according to FIG. 2;

[0040] FIG. 3b a side view of the detail according to FIG. 3a;

[0041] FIG. 3c a perspective view of the detail according to FIG. 3a;

[0042] FIG. 4 a first end section of a low-pressure mercury vapor discharge lamp according to a third embodiment;

[0043] FIG. 5 a low-pressure mercury vapor discharge lamp according to a fourth embodiment;

[0044] FIG. 6 a low-pressure mercury vapor discharge lamp according to a fifth embodiment;

[0045] FIG. 7 the region of the discharge path of a low-pressure mercury vapor discharge lamp according to the invention;

[0046] FIG. 8 a low-pressure mercury vapor discharge lamp according to a sixth embodiment;

[0047] FIG. 9 a low-pressure mercury vapor discharge lamp according to a seventh embodiment; and

[0048] FIG. 10 a low-pressure mercury vapor discharge lamp according to an eighth embodiment.

[0049] In the following description of specific embodiments on the basis of the figures, the same or similar components are provided with the same or similar reference signs for better readability. FIG. 1 shows a stylized lamp system 100 with a low-pressure mercury vapor discharge lamp 1 according to the invention. The low-pressure mercury vapor discharge lamp 1 comprises as an essential component a discharge vessel 6, with a first end section 61 and a second end section 62, which encloses a discharge chamber 8 in a gas-tight manner. During operation of the low-pressure mercury vapor discharge lamp, a filler gas and mercury vapor are contained in the discharge chamber 8.

[0050] The low-pressure mercury vapor discharge lamp 1 further comprises a first electrode 11 arranged on the first end section 61 and a second electrode 12 arranged on the second end section 62 for maintaining a discharge along a discharge path 13. Outside the discharge path 13 between the first electrode 11 and the second electrode 12 an amalgam deposit 18 for regulating the mercury vapor pressure in the discharge chamber 8 is arranged by means of an adhesion agent 17. The position of the amalgam deposit 18 is defined by the position, shape and size of the adhesion agent 17.

[0051] FIG. 1 shows a schematic section through the lamp system 100 with the low-pressure mercury vapor discharge lamp 1 provided therein through a plane which extends in the axial direction A and the first lateral direction (longitudinal direction) or radial direction X of the low-pressure mercury vapor discharge lamp 1. The low-pressure mercury vapor discharge lamp 1 can have a substantially axial extension, wherein the discharge vessel 6, particularly in the region surrounding the discharge path 13 in the radial direction X, Y, has a circular cross-section and/or can be designed in the form of a cylindrical tube. It is clear that the first end section 61 and the second end section 62 of the discharge vessel 6 seal off the discharge vessel 6, which is in the form of a cylindrical tube, in the axial direction A in the region of the discharge path 13. In this respect, the end sections 61, 62 necessarily have a shape that deviates from the cylindrical tube shape, in particular at their axial ends.

[0052] It can be preferred that the second end section 62 is produced by a stamping or crimping process, wherein for this purpose a cylindrical tube formed, for example, from quartz glass and forming the discharge vessel 6 is heated and, in a softened state, in an in particular second radial direction (transverse direction) Y is formed in a sealing manner for closing the discharge vessel 6. Referring in particular to lamps 1b and 1c, described below with respect to FIGS. 5 and 6, the first end section 61b or 61c thereof can also be shaped in such a way.

[0053] The end sections 61, 62 of the discharge vessel 6 can be arranged on a diametrically opposed axial foot of the emitter, in particular in such a way that the discharge path 13 between the first electrode 11 and the second electrode 12 extends substantially in the axial direction A. Other lamp shapes, for example omega-shaped, circular, spiral or the like, are conceivable.

[0054] An amalgam deposit 18, which is located outside the discharge path 13, which extends between the electrodes 11, 12, is arranged on the first end section 61 of the low-pressure mercury vapor discharge lamp 1 in the discharge chamber 8. Thanks to the arrangement of the amalgam deposit 18 outside the discharge path 13, the temperature 18 can be adjusted independently of the temperature of the arc along the discharge path 13 between the electrodes 11, 12 during the operation of the lamp 1. In order to adjust the temperature of the amalgam deposit 18, a controller and/or regulator can be provided. In the preferred embodiment shown in FIG. 1, regulation electronics 103 for regulating the temperature of the amalgam 18 are provided, which will be discussed in detail below.

[0055] To fix the arrangement of the amalgam 18 within the discharge chamber 8, an adhesion agent 17 is provided on the first end section 61 outside the discharge path 13. A metal, in particular an amalgam former, for example gold, in a preferably thin layer of less than 10 .Math.m on an inner surface in the interior of the discharge vessel 6, can be attached as adhesion agent 17. The adhesion agent 17 serves to define a position at which the amalgam 18 collects within the discharge vessel 6 at low temperatures below the melting point of the amalgam 18.

[0056] The adhesion agent 17 is selected such that, on the one hand, a stable connection is created with a material of the discharge vessel 6, such as a quartz glass and, on the other hand, a connection is created with the amalgam deposit within the discharge vessel. The adhesion agent 17 can comprise or consist of a material which causes minimum mercury vapor pressure in the discharge chamber 8 locally in the region of the adhesion agent 17, so that mercury vapor in the discharge chamber 8 of the low-pressure mercury vapor discharge lamp condenses and/or resublimates completely or at least predominantly on the adhesion agent 17.

[0057] The lamp system 100 can have a device for controlling the temperature of the amalgam deposit 18, which device is realized in the example shown in FIG. 1 by way of example by a heating device in the form of an electromagnetic transmitter 107, which induces an electromagnetic receiver 7 to heat the amalgam 18 in a heating current for controlling the temperature of the amalgam deposit 18.

[0058] To regulate the temperature, the lamp system 1 can comprise at least one temperature sensor 105, 106. The regulation electronics 103 can be configured to control the temperature control device, for example the inductive heater 109, in order to keep the amalgam temperature as constant as possible, in particular close to the predetermined ideal temperature of the amalgam 18. The regulation electronics 103 can be configured to keep the temperature of the amalgam 18 within a range ±10° C., in particular within a range ±5° C., preferably within a range ±2° C. or ±1° C. with respect to its specific, predetermined ideal temperature.

[0059] A temperature sensor can be provided, for example, as a lamp temperature sensor 106 for detecting a temperature on or in the lamp, in particular for detecting the temperature of the amalgam 18. The mercury vapor pressure of the amalgam is strongly dependent on the amalgam temperature, as described above. The use of a lamp temperature sensor 106 for detecting the temperature of the amalgam 18 during the operation of the lamp system 100 allows regulation of the temperature of the amalgam 18 using the temperature of the amalgam deposit 18 detected with the lamp temperature sensor 106 as a manipulated variable.

[0060] Alternatively or additionally, an ambient temperature 105 for detecting an ambient temperature of the lamp 1, for example a temperature of a medium m, such as service water, can be detected. To regulate the temperature of the amalgam 18, the regulation electronics 103 can take into account an ambient temperature detected with the ambient temperature sensor 105 as an alternative to or in addition to the amalgam temperature.

[0061] The regulation electronics 103 can in particular be designed to take into account significant changes in the ambient temperature if the temperature detected with the ambient temperature sensor 105 exceeds a predetermined maximum threshold value or falls below a predetermined minimum threshold value within a predetermined period of time or, in the case of a temporally discrete measurement, within a predetermined number immediately after one another recorded of measurement. In the case of significant changes in the ambient temperature, the regulation electronics 103 can bring about a corresponding control of the temperature control device, for example of the inductive heater 109, in order to keep the amalgam temperature as constant as possible, in particular close to the predetermined ideal temperature of the amalgam 18.

[0062] The lamp system can comprise a first holder 101, which is provided with connection contacts or contact receptacles 121 for providing the discharge current to the contact wires 21 of the first electrode 11. The lamp system 100 can have a second holder 102 with contacts or contact receptacles 122 for the contact wires 22 of the second electrode 12 to provide the discharge current to the second electrode 12.

[0063] According to one embodiment, the low-pressure mercury vapor discharge lamp 1 can have an electromagnetic receiver 7 for converting electromagnetic input signals into heat for heating the amalgam deposit 17. In the embodiments shown in FIG. 1, the receiver 7 is formed from the adhesion agent 17 and the amalgam deposit 18 provided on the adhesion agent 17. The receiver 7 can be annular, for example. The electromagnetic transmitter 107 for inductively and/or capacitively transmitting the heating current to the electromagnetic receiver 7 is arranged outside the discharge vessel 6.

[0064] The electromagnetic transmitter 107 can be configured to provide an electromagnetic field or signal for the receiver 7, in particular corresponding to a resonance frequency of the receiver 7. The transmitter 107 can be structurally matched to the receiver 7. It is conceivable that the transmitter 107 is matched to the receiver 7 of a low-pressure mercury vapor discharge lamp 1, in particular its resonance frequency, by means of a calibration process carried out by a regulation device 103.

[0065] In addition to the contact receptacles 121, the regulation electronics 103, the ambient temperature sensor 105, the lamp temperature sensor 106 and/or the temperature control device, in particular the electromagnetic transmitter 109, can also be accommodated in the housing of the holder 101 (if present).

[0066] An optional heat shield 4, which shields the amalgam deposit 18 from heat radiation from the first electrode 11, is provided in the discharge chamber 8 of the low-pressure mercury vapor discharge lamp 1 between the amalgam deposit 18 and the first electrode 11. In the low-pressure mercury vapor discharge lamp 1, the distance s in the axial direction A between the incandescent body of the first electrode 11 and the amalgam deposit 8 can be dimensioned such that, during operation of the mercury discharge lamp 1 with nominal power, the temperature of the amalgam deposit 18 is independent of the temperature of the incandescent body of the first electrode 11.

[0067] FIG. 2 shows another embodiment of a low-pressure mercury vapor discharge lamp 1a according to the invention, which differs from the low-pressure mercury vapor discharge lamp shown in FIG. 1 as essentially only by the heat shield 4. The use of the heat shield 4 allows a particularly compact design. In comparison, with parameters which otherwise remain the same, the distance s.sub.a between the first electrode 11 and the amalgam deposit 18 in the lamp 1a shown in FIG. 2 is greater in comparison to the lamp 1 described above, in order that the temperature of the amalgam deposit 18 is independent of the temperature and of the associated heat radiation of the incandescent body of the first electrode 11 when the low-pressure mercury vapor discharge lamp 1a is operating at nominal power.

[0068] FIG. 3a shows a detail section of a low-pressure mercury vapor discharge lamp 1 according to the intersection line III-III in FIG. 2. FIG. 3b shows a plan view of the first end section 61 of the emitter 1a according to FIGS. 3a and 2. FIG. 3c shows a perspective view of the first end section 61a of the emitter according to FIGS. 3a and 3b.

[0069] As can be seen in FIG. 3a, the contact wire 21 of the first electrode 11 in the axial direction A on the first end section 61a of the low-pressure mercury vapor discharge lamp 1 A is in sections continuously and completely surrounded by a dielectric sheathing 3. The dielectric sheathing 3 can be formed, for example, from a ceramic material or a glass material, preferably quartz glass. In particular, the sheathing 3 can be formed from the same material as the discharge vessel 6a. The adhesion agent 17 with an amalgam deposit 18 placed thereon is applied to a lateral surface of the sheathing 3.

[0070] The fixing of the adhesion agent 17 to the inner surface of the low-pressure mercury vapor discharge lamp can be achieved, for example, by melting the material of the adhesion agent 17 by brief heating and/or by burning in of the inner surface of the low-pressure mercury vapor discharge lamp. The amalgam deposit 18 can be fixed on the adhesion agent 17 by melting the amalgam deposit by heating briefly. The adhesion agent 17 preferably has a significantly higher melting point than the amalgam deposit 18. For example, the melting point of the amalgam deposit 18 can be below 200° C., in particular below 100° C. The melting point of the adhesion agent 17 can be, for example, at least 400° C., in particular at least 600° C. or more.

[0071] As can be seen in FIG. 3c, the sheathing 3 can extend continuously in a tape-like manner in the axial direction A along the contact wire 21. The first lateral direction X (longitudinal direction) and the second lateral direction Y (transverse direction) can be transverse, in particular perpendicular to one another, and be transverse, in particular perpendicular, on the axial direction A. The sheathing 3 can have a substantially rectangular cross-section In the axial direction A. In the first lateral direction X, the sheathing 3 has a width b that is smaller than the inner diameter D of the discharge vessel 6 in the region of the discharge path 13. The thickness d in the second lateral direction Y of the sheathing 3 is smaller than the inner diameter D of the discharge vessel 6a in the region of the discharge path 13. The thickness d of the sheathing 3 is smaller than the width b of the sheathing 3.

[0072] The sheathing 3 can be formed by the dielectric material, in particular a glass material, preferably quartz glass, being crimped or stamped or pressed onto the contact wire or contact wires 21 of the first electrode 11. The crimping or stamping of the sheathing 3 onto the contact wires 21 of the first electrode 11 can be carried out according to the crimping process described above. The sheathing 3 projects from the connection section 64 into the discharge chamber 8 of the lamp 1 in the axial direction A. The end 60 of the lamp 1 forms its outermost position in the axial direction A, at which, for example, the cylindrical cladding tube 66 of the emitter is combined with the connecting section 64 in particular without crimping. The sheathing 3 of the contact wires 21 is arranged inside the lamp 1, at a distance from its end 60 in the axial direction A, in order to avoid undesired conductive heat transfer from the amalgam deposit 18 to the lamp holder (not shown). Undesired conductive heat transfer from the temperature-controlled amalgam deposit 18 through the end 60 of the lamp 1 to the lamp holder is also prevented by the amalgam deposit 60 not being provided in a recess at the end 60 of the lamp, but instead being held by the adhesion agent 17 in the discharge chamber 8.

[0073] The contact wire 21 of the electrode 11 can be formed in sections as a round and sectionally laminar flat section, wherein it may be preferred to initially form the contact wire 21 as flattened sealing platelet 43 in the region of the sheathing 3 in order to bring about a strong sealing effect between the dielectric material of the sheathing 3 and the electrically conductive material of the contact wire 21. The contact wire 21 can in particular be formed from molybdenum.

[0074] The width b of the sheathing 3 is slightly less than the inner diameter D. In particular, the width b of the sheathing 3 can be between 75% and 90% of the inner diameter D. The thickness D of the sheathing 3 can preferably be less than half the inner diameter D, preferably between 20% and 30% of the diameter D.

[0075] The tape-shaped sheathing 3 extends in the axial direction A continuously along a height h over the entire circumference around the at least one contact wire 21 of the first electrode 11. The height h can be greater than the thickness d and/or smaller than the width b of the sheathing 3. The height h can correspond to the inner diameter D of the discharge vessel or be smaller than the inner diameter D of the discharge vessel 6a. The height can correspond to at least 50% and/or at most 150% of the inner diameter D of the discharge vessel 6a. Preferably, the height may correspond to at least 66% and/or at most 100% of the inner diameter. According to one embodiment, the height h can correspond to approximately 75% of the inner diameter D.

[0076] The adhesion agent 17 and the amalgam deposit 18 are arranged on at least one lateral surface (longitudinal side) 31 or (transverse side) 32 of the sheathing 3. The amalgam deposit 18 is arranged on a lateral side face 31 or 32 facing out of the discharge vessel 6 in the first lateral direction X or the second lateral direction Y. The end face 33 of the sheathing 3 facing the electrode 11 is free of adhesion agent 17 and free of amalgam 18.

[0077] In the embodiments shown in FIGS. 3a, 3b and 3c, the adhesion agent 17 with the amalgam deposit 18 is provided on a wide lateral surface 31 of the sheathing 3 extending in the first lateral direction X. It is conceivable that an adhesion agent 17 with an amalgam deposit 18 is arranged exclusively on just one of the lateral surfaces 31 and 32 of the sheathing 3. Alternatively, the adhesion agent and optionally the amalgam 18 can be arranged on two or three, in particular on all lateral surfaces 31, 32 of the sheathing 3.

[0078] The distance s.sub.a between the amalgam deposit 18 and the incandescent body of the electrode 11 is dimensioned such that the temperature of the amalgam deposit 18 is independent of the discharge current of the first electrode 11 when the low-pressure mercury vapor discharge lamp 1a is operating at nominal power.

[0079] The sheathing 3 can be connected at its foot facing in the axial direction A away from the first electrode 11 via a plate-like connecting section 64 to the cylindrical jacket 66 of the discharge vessel 6a in the first end section 61a of the lamp 18. The connecting section 64 can be designed to form a sealing closure of the discharge chamber 8 on the first end section 61a of the lamp 1a in the axial direction A. For example, the connecting section 64 can be formed integrally with the cladding tube 6a. The connection point of connecting section 64 and jacket 66 forms the first end 60 of the emitter 1a.

[0080] FIG. 4 shows a first end section 61 d of an alternative embodiment of a low-pressure mercury vapor discharge lamp 1d, which essentially corresponds to the previously described embodiment according to FIG. 2 to 3c. In contrast to the embodiment according to FIGS. 3a to c, the discharge vessel 6d is formed in the region of the discharge path 13 between the first electrode 11 and the second electrode with a larger internal diameter D than on the axial foot section 67, which surrounds the sheathing 3 in the lateral direction X; Y.

[0081] In the first end section 61d, the discharge vessel 6d has a tapered foot section 67 with a reduced internal diameter D.sub.d which is smaller than the inner diameter D of the discharge vessel 6d in the region of the cylindrical tube section 66 which surrounds the first electrode 11 and the discharge path 13.

[0082] The arrangement of the amalgam deposit 18 in a tapered foot section 67 can have a stabilizing effect on the mercury vapor pressure in the discharge chamber 8 in the region of the amalgam deposit 18. A transition section 68 can be provided between the foot section 67 and the cylindrical tube section 66, wherein the inner diameter of the discharge vessel 6 preferably changes continuously along the transition section 68. In the low-pressure mercury vapor discharge lamp 1d, the axial distance S.sub.d between the incandescent body of the electrode 11 and the amalgam deposit 18 can be smaller than in a low-pressure mercury vapor discharge lamp of the previously described embodiment 1a.

[0083] In the cylindrical tube section 66, the foot section 67 and/or the transition section 68, the wall thickness w of the discharge vessel 6d can be of equal size. In the case of a low-pressure mercury vapor discharge lamp, it may be preferred that the wall thickness w of the discharge vessel is constantly the same size. For example, the wall thickness w of the discharge vessel 6d (as well as 6 or 6a) can correspond to the wall thickness w of the cylindrical tube section 66 in a connection section 64 between the sheathing 3 and the electrode 11.

[0084] The low-pressure mercury vapor discharge lamps 1b and 1c shown in FIGS. 5 and 6 differ from the low-pressure mercury vapor discharge lamp 1 described above substantially only by the shape of the first axial end of the discharge vessel and the arrangement of the adhesion agent 17b, 17c with amalgam deposit 18. It is clear that a low-pressure mercury vapor discharge lamp according to the invention can have several amalgam deposits 18 on corresponding adhesion agent sites at several positions outside the discharge path 13. For example, the low-pressure mercury vapor discharge lamp 1 could have at least one further amalgam deposit corresponding to the arrangement according to FIG. 5 and/or FIG. 6 in addition to the amalgam deposit 18 shown in FIG. 1. In the first end 60, no recess or the like that impairs the stability of the lamp needs to be provided for the amalgam, since the amalgam is advantageously fixed in the discharge chamber 18 by the adhesion agent 17b, 17c. In this way, an undesired conductive heat transfer from the temperature-controlled amalgam deposit 18 in the direction of the axial end 60 of the lamp 1b, 1c and a lamp holder (not shown in more detail) surrounding the end 60 is also prevented.

[0085] FIG. 5 shows an alternative embodiment of a low-pressure mercury vapor discharge lamp 1b according to the invention, in which the amalgam deposit 18 is arranged with an adhesion agent 17b on the inner side 63 of the discharge vessel 6b. Optionally, a heat shield 4b can be arranged between the first electrode 11 and the amalgam deposit 18. The axial distance S.sub.b is dimensioned between the amalgam deposit 18 and the incandescent body of the first electrode 11 such that the temperature of the amalgam deposit 18 is independent of the discharge current of the first electrode 11. The amalgam deposit 18 is arranged with the adhesion agent 17b on the radial inner side 63 of the discharge vessel 6b facing away from the discharge region 13.

[0086] The first end section 61 b of the low-pressure mercury vapor discharge lamp 1b b can be formed corresponding to the second end section 62 by pressing of cylindrical tube of the discharge vessel 6b onto the respective contact wires 21, 22 of the electrodes 11 and 12 located opposite one another. The first end 60 of the low-pressure mercury vapor discharge lamp 1b (or 1c) can thus be formed as a pressed end 60 on the first end section 61b (or 61c) of the discharge vessel 6b (or 6c), which extends completely outside the discharge chamber 60.

[0087] FIG. 6 shows a further alternative embodiment of a low-pressure mercury vapor discharge lamp 1c according to the invention. The distance S.sub.c between the amalgam deposit 18 and the incandescent body of the electrode 11 is very small. Nevertheless, the temperature of the amalgam deposit 18 is independent of the discharge current of the first electrode 11. A heat shield 4c is arranged between the electrode 11 and the amalgam deposit 18. The amalgam deposit 18 is arranged on the rear side of the heat shield 4c facing away from the electrode 11 and thus the discharge vessel 6c or its discharge region 13.

[0088] The heat shield 4c (or 4 or 4b) is preferably formed from an infrared radiation to an extent of at least 90%, at least 95%, at least 99%, preferably at least 99.9%. For example, the heat shield 4c is formed from a ceramic material or a quartz glass, in particular an amorphous quartz glass, such as a semiconductor-doped amorphous quartz glass. It is conceivable that the heat shield 4c has a surface facing the electrode 11, which surface is coated with a highly reflective material (relative to the infrared spectrum).

[0089] The adhesion agent 17c and the amalgam 18 are attached to the rear side, facing away from the electrode 11, of the heat shield 4c. Axial stops 21 are fastened to the contact wires 21 in order to fix the heat shield 4c at least in the axial direction A. The heat shield 4c has two circumferential contact sections 41 which are in contact with the inner side 63 of the discharge vessel 6c. The circumferential contact sections 41 form an almost circular reflector surface. In the circumferential direction between the circumferential contact sections 41, the heat shield 4c has two radial recesses 43 in which the contact wires 21 are guided and which each provide a gas-permeable opening between the discharge path 13 and the end section 61c, so that mercury vapor can be exchanged between the discharge path 13 and the amalgam deposit 18.

[0090] The discharge vessel 6c can be formed similar to the discharge vessel 6b previously described with respect to FIG. 5 with end sections 61c and 61b and 62 that are equal to one another.

[0091] FIG. 7 makes it clear that the discharge path 13, as defined herein, basically comprises the complete volume element of the interior of the discharge vessel 6, 6a, 6d in the region between and including the incandescent body of the first electrode 11 and the incandescent body of the second electrode 12, but not the axial end regions of the discharge vessel 6, 6a, 6d beyond the electrodes 11, 12. According to the invention, the position of the amalgam deposit 18 is located outside this discharge path 13 which is represented by dots.

[0092] FIG. 8 shows an embodiment of a low-pressure mercury vapor discharge lamp according to the invention, in which a disk-like heat shield 4 is arranged between the incandescent body of the first electrode 21 and the amalgam 18. The amalgam 18 is held on the inside of the discharge vessel by means of an adhesion agent 17. The heat shield 4 has recesses 43. The disk-like heat shield 4 has two radial recesses 43 in the circumferential direction. The heat shield 4 is configured to thermally shield the amalgam deposit 18 from the incandescent body of the first electrode 21.

[0093] FIG. 9 shows a further embodiment of a low-pressure mercury vapor discharge lamp according to the invention, in which a disk-like heat shield 4 is likewise arranged between the incandescent body of the first electrode 21 and the amalgam 18. In addition, a sleeve 80 made from a material that reflects infrared light is arranged on the inside of the discharge vessel, so that it surrounds the amalgam deposit 18 from several sides in a shell-like manner in order to thermally shield the amalgam deposit 18 from the incandescent body of the first electrode 21. The heat shield 4 carries a coating 70 made from a material that reflects infrared light, in this example aluminum. In this example, the coating 70 is arranged on the side of the heat shield 4 facing the incandescent body of the first electrode 21. Alternatively, however, it is also possible to attach the coating 70 to the opposite side or to both sides of the heat shield 4. A disk-like heat shield 4 with a coating 70 reflecting infrared light can be provided as an alternative to or in addition to the sleeve 80.

[0094] FIG. 10 shows a further embodiment of a low-pressure mercury vapor discharge lamp according to the invention, in which a layer 90 made from a material that reflects infrared light is arranged on the outside of the discharge vessel in order to thermally shield the amalgam deposit 18. Such a layer 90 can comprise, for example, aluminum or a precious metal, such as gold or silver.

[0095] Reference signs [0096] 1, 1a, 1b, 1c, 1d Low-pressure mercury vapor discharge lamp [0097] 3, 3d Sheathing [0098] 4, 4b, 4c Heat shield [0099] 6, 6a, 6d Discharge vessel [0100] 7 Receiver [0101] 8 Discharge chamber [0102] 11 First electrode [0103] 12 Second electrode [0104] 13 Discharge path [0105] 17, 17b Adhesion agent [0106] 18 Amalgam deposit [0107] 21, 22 Contact wire [0108] 23 Axial stop [0109] 25 Sealing platelets [0110] 27 Transition region [0111] 41 Circumferential contact section [0112] 43 Recess [0113] 60 First end [0114] 61, 61a, 61 d First end section [0115] 62 Second end section [0116] 63 Inner side [0117] 64 Connecting section [0118] 66 Cylindrical tube section [0119] 67 Foot section [0120] 68 Transition section [0121] 70 Coating of the heat shield [0122] 80 Sleeve [0123] 90 Layer [0124] 100 Lamp system [0125] 101, 102 Holder [0126] 103 Regulation electronics [0127] 105 Ambient temperature sensor [0128] 106 Lamp temperature sensor [0129] 107 Transmitter [0130] 121, 122 Contact receptacle [0131] b Width [0132] d Thickness [0133] h Height [0134] m Ambient medium [0135] s, s.sub.a, S.sub.b, S.sub.c, S.sub.d Distance [0136] w Wall thickness [0137] A Axial direction [0138] D, D.sub.d Internal diameter [0139] X First radial direction [0140] Y Second radial direction