WO2008009572A2

WO2008009572A2 - Discharge lamp, particularly low-pressure discharge lamp

Info

Publication number: WO2008009572A2
Application number: PCT/EP2007/056872
Authority: WO
Inventors: Armin Konrad; Stephan Appel
Original assignee: Osram Gesellschaft mit beschränkter Haftung
Priority date: 2006-07-20
Filing date: 2007-07-06
Publication date: 2008-01-24
Also published as: EP2044615A2; WO2008009572A3; DE102006033675A1; KR20090031695A

Abstract

The invention relates to a discharge lamp, particularly a low-pressure discharge lamp, comprising a discharge vessel (2), two electrodes (3, 4) that are disposed at least in part inside the discharge vessel (2), and a first coating (9) which is arranged at least in some areas of an external face (23) of the discharge vessel (2) and is made of a first material. A second coating (10a, 10b) made of a second material is placed on the external face (23) of the discharge vessel (2), in the area (24, 25) of at least one electrode (3, 4).

Description

description

Discharge lamp, in particular low-pressure discharge lamp

Technical area

The invention relates to a discharge lamp, in particular a low-pressure discharge lamp, comprising a discharge vessel and two electrodes disposed at least partially in the discharge vessel and a first coating of a first material arranged at least partially on an outer side of the discharge vessel.

State of the art

A known from the prior art low-pressure discharge lamp is shown schematically in Fig. 1. This low-pressure discharge lamp embodied as a fluorescent lamp 1 comprises a tubular discharge vessel 2 at whose opposite end regions 21 and 22 an electrode 3 or 4 is respectively arranged on sockets 5 and 6. To the outside each contact pins 7a, 7b and 8a and 8b extend. On an outer side 23 of the discharge vessel 2, a coating 9 is applied, which extends substantially over the length of the fluorescent lamp 1. This coating 9 is formed as a plastic coating. The plastic layer has over the entire length (y-direction) a substantially constant thickness and a constant outer diameter. In the case of the fluorescent lamp 1 known from the prior art, there is a problem in that for most plastics a sufficient thermal and also a sufficient UV (ultraviolet) resistance is only given for relatively lightly loaded fluorescent lamps 1. So this is generally only given for fluorescent lamps 1 with a discharge current <200 mA. For highly loaded lamps, which have a larger discharge current, this requirement for the coating is no longer met. Presentation of the invention

It is therefore an object of the present invention to provide a discharge lamp, the outer coating having sufficient thermal resistance even for relatively high-loaded discharge lamps.

This object is achieved by a discharge lamp having the features of claim 1.

A discharge lamp according to the invention is designed in particular as a low-pressure discharge lamp. The discharge lamp comprises a discharge vessel and a first and a second electrode, which are arranged at least partially in the discharge vessel. On an outer side of the discharge vessel a first coating is at least partially arranged, which is formed of a first material. In the region of at least one electrode, a second coating of a second material is arranged on the outside of the discharge vessel. On the outside of the discharge vessel thus different location-dependent layers are applied, which due to their arrangement and / or their material properties, an outer coating can be achieved, which allow sufficient functionality even for relatively high-loaded discharge lamps. In particular for discharge lamps with discharge currents> 200 mA, in particular with a discharge current> 300 mA, a significantly improved functionality can be achieved thereby. Furthermore, this outer coating can be colored or pigmented as desired.

In a preferred manner, in each case a second coating is formed in the region of the first electrode and in the region of the second electrode on the outside of the discharge vessel. In particular, when both electrodes are relatively hot during operation, and as a result of which the region of the discharge vessel adjacent to the electrodes is exposed to an increased temperature load and also to increased UV emission this dual-sided regional arrangement of the second coating provides a multilayer arrangement sufficient for the underlying functionality. As a result of the second coating provided only in critical areas, in addition to achieving the optimum functionality of the layer arrangement, a relatively cost-effective implementation and a material-saving design can be made possible.

The second coating is preferably arranged directly on the outside of the discharge vessel and the first coating is formed on the second coating. It may be provided that the first coating, the second coating at least partially or completely covered. In a complete overlap, the second coating is thus contacted only with the outside of the discharge vessel on the one hand and with the first coating on the other hand. The second coating is completely enclosed in such an embodiment by these two components, the first coating and the outside of the discharge vessel. In addition to an at least partial contact, in particular a full-surface contact, the first with the second coating, the second coating may also be arranged so that it is at least partially directly on the outside of the discharge vessel. However, here as well, it can be provided that the second coating, with its side facing the discharge vessel, rests completely on this outside of the discharge vessel. Depending on the configuration of the discharge vessel and / or the configuration of the second coating, an optimal arrangement can thus be achieved in a flexible manner as required and with regard to the desired functionality.

The first coating is preferably arranged outside the second coating directly on the outside of the discharge vessel. Again, an at least partially immediate attachment of the first coating can be provided. In particular, in an embodiment in which - A -

At least two second coatings are provided, these are each formed as separate coatings and positioned separately from each other. By arranging the first coating directly on the outside of the discharge vessel, the first coating can also be provided as a separating element between the two second coatings. Preferably, the first coating and the second coating are arranged such that in areas in which both coatings are arranged one above the other, the resulting layer system is made thicker than in areas in which only one coating is present. In particular in the region of at least one electrode, a thicker layer arrangement can then be formed on the outside of the discharge vessel than in regions of the outside of the discharge vessel which are remote therefrom. Both the temperature resistance and the UV resistance can thus be optimally achieved, as required, in virtually all areas on the outside of the discharge vessel. Preferably, the materials of the two coatings are different. For the first coating, a plastic coating is preferably provided. For example, materials such as VPE (crosslinked polyethylene), PET (polyethylene terephthalate), PC (polycarbonate) may be provided here. The explicit list of plastics is merely exemplary and may include other plastics.

For the materials of the second coating glass materials or ceramics are advantageously used. Plastic materials may also be provided. For example, plastic materials include HDPE (high-density polyethylene), POCAN, silicones, FEP (perfluoro (ethylene-propylene) plastic), PTFE (polytetrafluoroethylene) or PC (polycarbonate). Even these explicit plastic materials are not to be considered exhaustive in their list and are merely exemplary.

The first coating and the second coating may also be formed of a same material. The functionality with regard to a Sufficient thermal and also sufficient UV resistance can then be achieved, for example, via a thickness variation in explicit regions on the outside of the discharge vessel.

In addition to the abovementioned specific materials for the first coating and for the second coating, it is also possible to provide material connections in each case.

Preferably, the first coating extends over the entire outside of the discharge vessel.

The materials of the first coating are preferably designed such that they can also be used functionally with regard to splinter protection and / or as spectral filters. It can be provided that the second coating is formed from a material which allows at least a sufficient function as a spectral filter. In particular, the materials can be designed such that, with regard to the spectral filter function, they also enable the generation of saturated light colors, for example red, green, blue, yellow, of the discharge lamp. The function of a sufficient UV protection is advantageously fulfilled by the coatings.

As a result, discharge lamps can be provided which can be used in a wide variety of applications. Thus, such discharge lamps can be used as light sources in the effect lighting with, for example, color-adaptive lighting systems. Discharge lamps with anti-shattering function and UV protection are important for food-producing and related companies producing, for example, packaging for these foods. In addition, discharge lamps which have suitable spectral filter functions can also be used in lithography technology in chip production.

Advantageously, the materials of the two coatings are designed such that the material of the second coating has a higher temperature stability. than the material of the first coating. By a temperature resistance or a thermal resistance of a material it is understood, inter alia, that the materials essentially retain their elastic properties under a relatively high temperature influence and that the materials do not depolume, do not oxidize and also do not become brittle.

The second coating preferably has a thickness or an extent from the surface of the discharge vessel to its surface facing away from the discharge vessel of less than 10 mm, in particular less than 6 mm and preferably in particular a thickness of between 0.5 mm and 5 mm. The thickness of the second coating may vary as well as the thickness of the first coating.

It can also be provided that the second coating is formed as a layer system and in turn comprises at least two coatings. Likewise, the first coating on its side remote from the outside of the discharge vessel may also be covered at least in regions with a further third layer. The first coating and optionally the second coating may also be formed as a multi-layer system.

Preferably, the discharge vessel is tubular and the two electrodes are arranged at opposite ends of the discharge vessel. The electrodes may be formed substantially equal in size and shape. However, it can also be provided that the electrodes have different size and shape. Preferably, both the first coating and the second coating in a tubular configuration of the discharge vessel in the radial direction are formed completely circumferentially. As a result, in particular a fluorescent lamp can be provided with an optimum coating system. Short description of the drawing (s)

An embodiment of the invention will be explained in more detail with reference to a schematic drawing. Show it:

Fig. 1 is a sectional view of a known from the prior art fluorescent lamp; and

Fig. 2 is a schematic sectional view of an inventive

Discharge lamp.

Preferred embodiment of the invention

FIG. 2 shows, in a schematic manner, a sectional view through a low-pressure discharge lamp embodied as a fluorescent lamp 1 '. The fluorescent lamp 1 'comprises a tubular discharge vessel 2, which may be, for example, a glass bulb. At opposite end portions 21 and 22 of the discharge vessel 2 each have an electrode 3 and 4 are arranged and fixed to an associated base 5 and 6. From the sockets 5 and 6 each extend two electrical contact pins 7a and 7b and 8a and 8b to the outside. On an outer side 23 of the discharge vessel 2, a second coating 10a is formed in the area 24 of the first electrode 3. The second coating 10a is completely circumferential in the radial direction of the discharge vessel 2 and thus arranged on the outside 23 in a ring-like manner. As can be seen, the second coating 10a, with its side facing the outside 23, lies directly on its entire surface on this outside 23. In the cross section shown, this second coating 10a has a hill-shaped structure. This is merely exemplary and may be embodied in a variety of other ways and shapes. In the exemplary embodiment, this second coating 10a extends in the longitudinal direction (y-direction) substantially from the discharge vessel 2 side facing the base 5 to about twice the distance Electrode socket on the outside 23. Also, this longitudinal extent of the second direction 10a is merely exemplary and may also be otherwise formed. It can be provided that the second coating 10a extends further in the longitudinal direction in the direction of the center of the discharge vessel 2 or else has a shorter design. Due to the cross-section of the hill-shaped configuration of the second coating 10a, this has a variable thickness (z-direction) over its longitudinal extent (y-direction).

On the side facing the base 5, the second coating 10a may also be formed, for example, to the outer end of the base 5.

In an analogous manner, a further second coating 10b is likewise formed in a region 25. In the exemplary embodiment, a second separate coating 10a or 10b is thus respectively provided in the regions 24 and 25 and thus in both regions of the electrodes 3 and 4 on the outside 23 of the discharge vessel 2. Both second coatings 10a and 10b are arranged separately from each other and formed without contact with each other. The arrangement and shaping as well as the material configuration of the further second coating 10b is designed analogously to the opposing second coating 10a.

The second electrode 4 is formed in the embodiment the same as the first electrode 3 and secured by a base 6 at the end portion 22 of the discharge vessel 2.

The two second coatings 10a and 10b have an extension of about 20 mm in the longitudinal direction and thus in the y-direction. Again, this value is merely exemplary and may be greater or less.

Moreover, a first coating 9 is arranged so as to completely cover both second coatings 10a and 10b at their free surfaces. As can be seen, the first coating 9 extends over the entire length of the discharge vessel 2 and the adjoining thereto. It can also be provided that this first coating 9 extends only over the entire length of the discharge vessel 2. However, it can also be provided that starting from the illustration in FIG. 2, the first coating 9 also extends as far as back walls 51 and 61 of the base 5 and 6 and is formed there directly adjacent.

Furthermore, it can be seen from the illustration in FIG. 2 that the first coating 9 is arranged in the middle of the discharge vessel 2 and thus between the second coatings 10a and 10b directly on the outside 23 of the discharge vessel 2.

The first coating 9 is also arranged completely circumferentially in the radial direction of the discharge vessel 2.

The first coating 9 has a substantially constant layer thickness (z-direction) over its entire longitudinal extent.

The arrangement of the first coating 9 and the second coatings 10a and 10b shown in the exemplary embodiment provides local layer systems which are formed with different thicknesses. The mode of operation of the discharge lamp 1 'can thereby be optimized. Particularly in the areas 24 and 25, in which due to the operation of the discharge lamp 1 ', an increased bulb temperature and increased UV emission occurs, the first coating 9 has no direct contact with the outside 23, but is mounted at a certain distance to this outside 23 , The second coatings 10a and 10b act as spacers in this context.

The materials of the second coatings 10 a and 10 b are selected to have a higher thermal resistance than the material of the first coating 9. Moreover, the second coatings 10 a and 10 b are formed in their central central area with a greater thickness than the thickness of the first coating 9.

The first coating 9 is formed as a plastic coating.

The second coatings 10a and 10b may be formed of an aforementioned material in view of the functions desired by the fluorescent lamp 1 '. In combination of the materials for the coatings 9, 10a and 10b as well as their shape and arrangement can be optimized with respect to the requirements of the discharge lamp or the fluorescent lamp 1 '.

The second coatings 10a and 10b may also be formed of several partial layers. Likewise it can be provided that at least one layer of air is also formed in the second coatings 10a and 10b. An air layer may also be formed between the first coating 9 and a second coating 10a or 10b.

It can also be provided that on the side facing away from the outer side 23 of the discharge vessel 2 of the first coating 9, at least in some areas, at least a further third layer is attached. For example, such a third layer may be applied to the first coating 9 in the region between the second coatings 10a and 10b. As a result, a planarization of the outwardly oriented surface of the first coating 9 can be achieved. Likewise, however, it may also be provided that this first coating 9 is made so thick in this region between the second coatings 10a and 10b that the outer surface of the first coating 9 is flat over the entire length.

Both the first material of the first coating 9 and the second materials of the second coatings 10a and 10b are such that the respective coatings can be used as splinter protection and / or as a spectral filter are. In addition, the selected materials also ensure sufficient thermal and also sufficient UV resistance for a fluorescent lamp 1 'with a discharge current> 300 mA.

In the embodiment shown, the second coatings 10a and 10b are thus arranged on both sides in the region of the end regions 21 and 22 of the discharge vessel 2.

Another significant advantage of a discharge lamp 1 'according to the invention is the fact that its manufacture and production can be relatively easily made possible. By using or attaching second coatings, a first coating can be applied, for example, in the form of a heat-shrinkable tube or by means of extrusion in one operation.

Claims

claims

1. discharge lamp, in particular low-pressure discharge lamp, with a discharge vessel (2) and two at least partially in the discharge vessel (2) arranged electrodes (3, 4) and on an outer side (23) of the discharge vessel (2) at least partially arranged first coating (9) of a first material, characterized in that in the region (24, 25) of at least one electrode (3, 4) on the outer side (23) of the discharge vessel (2), a second coating (10a, 10b) of a second material is arranged.

2. Discharge lamp according to claim 1, characterized in that in the region (24, 25) of the first electrode (3, 4) and in the region (24, 25) of the second electrode (3, 4) on the outer side (23) of the discharge - Fäßes (2) each have a second coating (10a, 10b) is formed.

3. Discharge lamp according to claim 1 or 2, characterized in that the second coating (10a, 10b) on the outside (23) of the discharge vessel (2) is arranged directly and the first coating (9) on the second coating (10a , 10b) is formed.

4. Discharge lamp according to one of the preceding claims, characterized in that the first coating (9), the second coating (10a, 10b) at least partially covered.

5. Discharge lamp according to one of the preceding claims, characterized in that the second coating (10a, 10b) is arranged such that it is arranged at least in regions directly on the outside (23) of the discharge vessel (2).

6. Discharge lamp according to one of the preceding claims, characterized in that the first coating (9) outside the second coating (10a, 10b) directly on the outside (23) of the discharge vessel (2) is arranged.

7. Discharge lamp according to one of the preceding claims, characterized in that a coating arrangement in areas (24, 25) in which both coatings (9, 10a, 10b) are arranged one above the other thicker than in areas in which only a coating ( 9) is present.

8. Discharge lamp according to one of the preceding claims, characterized in that the materials of the two coatings (9, 10a, 10b) are different.

9. Discharge lamp according to one of the preceding claims, characterized in that extending the first coating (9) over the entire length of the outer side (23) of the discharge vessel (2).

10. Discharge lamp according to one of the preceding claims, characterized in that the coatings (9, 10a, 10b) are temperature and UV-resistant.

1 1. Discharge lamp according to one of the preceding claims, characterized in that the materials of the coatings (9, 10a, 1 Ob) are formed so that the coatings (9, 10a, 1 Ob) can be used as splinter protection and / or as a spectral filter.

12. Discharge lamp according to one of the preceding claims, characterized in that the first coating (9) made of plastic, in particular made of VPE or of PET or PC, is formed.

13. Discharge lamp according to one of the preceding claims, characterized in that the second coating (10a, 10b) is formed of a glass material or glass-like material or of ceramic or plastic.

14. Discharge lamp according to one of the preceding claims, characterized in that the second coating (10a, 10b) has a higher temperature resistance, as the material of the first coating (9).

15. Discharge lamp according to one of the preceding claims, characterized in that the second coating (10a, 10b) has a thickness of less than 10 mm, in particular less than 6 mm, in particular a thickness between 0.5 mm and 5 mm.

1 6. Discharge lamp according to one of the preceding claims, characterized in that the electrodes (3, 4) at opposite end regions (21, 22) of the discharge vessel (2) are arranged.

17. Discharge lamp according to one of the preceding claims, characterized in that the discharge vessel (2) is tubular and at opposite end regions (21, 22) of the discharge vessel (2) in each case completely encircling the discharge vessel (2) two second laminations (10a, 10b) on the outer side (23 ), which are completely covered by the first coating (9) and the first coating (9) between the two second coatings (10a, 10b) is arranged directly on the outer side (23) of the discharge vessel (2).