WO2002023591A1 - Radiation source and irradiation device - Google Patents

Abstract

The invention relates to a radiation source (101) for electromagnetic radiation whose active component is in the near infrared range especially in the wavelength range, between 0.8 mu m and 1.5 mu m, for producing a long' extended irradiation area. The radiation source comprises a long' extended halogen lamp (101) which has a tubular glass body that is capped at the ends and has at least one spiral-wound filament; and a long' extended reflector (102). The ends of said halogen lamp or the contact retainers are positioned in heat-conductive contact with the reflector and/or cooling means (107, 108) for eliminating heat are allocated to the ends in such a way as to produce a steep T gradient between the middle area of the glass body and its ends, especially a T drop of a glass body temperature of more than 600 DEG C to an ends temperature of less than 300 DEG C, especially less than 200 DEG C.

Description

 Radiation source and radiation arrangement

description

The invention relates to a radiation source according to the preamble of claim 1 and an irradiation arrangement constructed with such a radiation source.

From the applicant's earlier patent applications, such as the

DE 197 36 462 AI, WO 99/42774 or P 10024731.8 (unpublished), methods for treating surfaces, processing materials and producing composite materials using electromagnetic radiation are known, the essential active component of which is in the near infrared range, in particular in the wavelength range between 0.8 μm and 1.5 μm. In a number of these applications, the realization of a relatively broad radiation zone is essential in the interest of high productivity of the respective process with a high power density. It is therefore known to use an elongated halogen lamp which has a tubular glass body with at least one filament at the ends and an elongated reflector as the radiation source.

In known radiation sources or radiation devices with elongated lamps with a base on both sides - for example for medical or lighting applications - the lamps have connections or bases which are arranged coaxially to the glass body at its ends; see. such as US 4,287,554 or DE 33 178 12 AI. These publications also describe radiation arrangements with a plurality of radiation sources which are arranged in parallel next to one another. With such a radiation source, a broad radiation zone with an approximately constant radiation flux density over its width can be realized, which in turn creates uniform process conditions over the corresponding width of the working area.

In the practical application of such radiation sources and radiation arrangements for generating radiation zones with energy densities above and sometimes far above 100 kW / m ² , problems have arisen with regard to a sufficient lifespan of the lamps and the dimensional stability of the reflector arrangements, which the inventors have found to be permanent thermal overload can be associated.

The invention is therefore based on the object of specifying an improved radiation source of the generic type which allows the generation of an irradiation zone with a very high radiation flux density, with a sufficiently long service life being ensured with reproducible radiation parameters.

This object is achieved by a radiation source with the features of claim 1.

According to the invention, the ends of the halogen lamp are expediently arranged in heat-conducting contact with the reflector and / or the ends are assigned coolants for heat dissipation. As a result, a steep temperature (T) gradient can be achieved between the middle and the curved regions of the glass body and the respectively adjacent end and end region. As a result, in particular a temperature drop from a temperature of the glass body above 600 ° C. to an end temperature significantly below 300 ° C., especially generated below 200 ° C and takes into account the thermal sensitivity of the lamp ends.

In a first special embodiment, the coolants mentioned comprise heat radiation surfaces (“flags”) at the ends of the lamp. In addition or as an alternative to this, plug-in contact sockets with special heat-conducting means for heat dissipation are provided on the (generally completely metallic and therefore very good heat-dissipating) reflector.

The flags mentioned are in particular thermally conductively firmly connected to the connecting pins of the lamp, for example welded. Their use is particularly advantageous when the radiation source is designed with a protective pane located in front of the halogen lamp and made of largely NIR-permeable material (quartz glass, glass or the like), in which a cooling gas flow is carried out between the halogen lamp and this protective pane to dissipate the absorbed in the protective pane Heat is carried along. This air flow is fed into a cooling fluid supply device arranged at one end of the lamp, sweeps along the protective pane in a substantially laminar manner and is drawn off at the other end of the lamp (in particular to the rear). If the flags are placed obliquely in this air flow, they are washed around them and the heat dissipation is accelerated - despite the fact that the cooling fluid flow is no longer “cold” at least at one lamp end.

With a suitable design of this arrangement, additional active cooling of the lamp ends, and the constructive one, can be dispensed with, at least for applications with medium lamp power

Effort for the lamp end cooling can be kept relatively low.

The use of a pressurized cooling fluid for the removal is even more efficient, even if it is more complex in terms of process technology. Conduction of heat from the lamp ends. For this purpose, the coolants comprise cooling fluid flow channels for supplying the cooling fluid to the ends or regions near the ends of the halogen lamp and / or the regions of the assigned reflector adjacent to them.

Specifically, at least one compressed air flow channel is provided in the reflector with outlet openings (“nozzles”) directed towards the ends of the halogen lamp, via which cold compressed air - or another cooling gas - is fed into these areas. In a preferred embodiment of this idea, a plurality of compressed air flow channels are provided in the reflector, each of which has outlet openings arranged and designed such that the compressed air (compressed air) supplied is swirled around the ends or regions near the end of the glass body. This turbulent flow ensures reliable heat dissipation from all surface areas to be cooled.

Another preferred embodiment has water channels in the reflector, which pass through areas near the base thereof. Cooling water is passed through these water channels, which on the one hand serves to cool the reflector (directly exposed to the radiation of the filament) and on the other hand - indirectly via the heat conduction between the reflector and lamp ends - also serves to cool the lamp ends.

A particularly advantageous way of heat dissipation is made possible by reflectors which are designed as solid extruded profiles made of a material with high thermal conductivity, in particular aluminum or an aluminum alloy. In such reflectors, namely, the cooling fluid flow channels (both in the version as compressed air channels and in the version as water channels) are particularly easy to incorporate, and the solid design of the reflector gives it a high level Heat capacity and thus helps to even out the heat radiation from the radiation source even with slight inhomogeneities in the primary radiation profile of the filament or with slight fluctuations in the supply voltage.

Such a reflector profile with particularly advantageous reflection properties, which contribute to a long lifespan of the halogen lamp, and with particularly easy handling in a modular radiation system has an outer contour which is essentially rectangular in cross section and an essentially W-shaped reflector surface in cross section, whereby in particular two or three cooling fluid flow channels are incorporated in the foot area between the "W" and the rectangular outer contour.

In an embodiment suitable for many applications, in which the radiation source is not used in a row with others, end reflectors are preferably arranged adjacent to the ends of the halogen lamp. These stand at a right or obtuse angle from the main reflector, which runs over the longitudinal extent of the halogen lamp and is parallel to its longitudinal axis, in the manner of side cheeks. Their length is expediently chosen so that they extend beyond the extension of the longitudinal axis of the halogen lamp.

The end reflectors also preferably have cooling devices, in particular at least one compressed air channel which extends into the end reflector and there has at least one outlet opening - preferably a plurality of outlet openings. A particularly advantageous turbulent flow around the lamp ends with cooling air or gas is achieved in a further embodiment in which outlet openings are provided both in the main reflector and in the end reflectors. These are aligned with one another at such predetermined angles. That the areas of the vitreous body closest to the base are most subjected to cooling air and that an efficient swirling is effected in these areas.

According to a further preferred embodiment of the invention, the lamp ends - based on the material or semi-finished product to be processed - are laid behind the glass body with an incandescent filament via which NIR radiation is emitted. The design also includes the idea of realizing this rearward laying of the ends by bending the glass body in the area near the base.

A further advantageous variant consists in making the incandescent filament or (if several incandescent filaments are present in the glass body) thickened in the area near the end mentioned, so that relatively more radiation energy is imitated in the NIR range there. This counteracts the expected drop in radiation flux density at the bent ends of the glass body despite the fact that the ends have been moved backwards. The degree of thickening of the incandescent filament is to be determined as a function of the concrete shape or the radius of the bend in the glass body - which is within the constructive discretion of the person skilled in the art and for which other comparative tests with different patterns can provide sufficient clues.

In an embodiment which is preferred because of its simplicity, at least one end of the halogen lamp is bent substantially rectangularly with respect to its longitudinal extent over a radius of curvature. In this case, the lamp connections basically run at right angles to the longitudinal extension of the glass body and the incandescent filament, so that the lamp connections of halogen lamps arranged one behind the other can be easily realized. In an alternative embodiment to this, at least one end of the halogen lamp has a region of a C-shaped bend, such that the outermost point of the base assigned to this end is slightly offset inwards relative to the outermost point of the glass body at this end. It is also possible to design halogen lamps whose glass bodies have the latter geometry at one end, while the right-angled bend mentioned above is implemented at the other end. The last-mentioned version enables (even if with somewhat higher construction effort with regard to the halogen lamp) the "seamless" stringing together of radiation sources in order to realize a very broad radiation field with an almost completely constant radiation flux density, since more space is available for the current supply to the lamp bases stands.

A preferred radiation arrangement using the solution according to the invention comprises a plurality of radiation sources of the proposed type, at least two of which are arranged one behind the other on a line. Here, the radiation flux density is essentially constant over the entire longitudinal extent of the radiation sources lined up between the outermost points of the first and last radiation source that are facing away from one another. An advantageous implementation of an overall cooling system results in an expedient embodiment in which the cooling fluid flow channels of the radiation sources arranged in a row are aligned with one another and connected to form continuous flow channels. Each of these has a connection for supplying cooling fluid to a first of the radiation sources arranged in a row.

Such an irradiation arrangement is particularly suitable for the NIR drying of paints or plastic coatings - especially powder coatings -, for the production of plastic laminates or for thermal treatment (especially drying and / or crosslinking). tongue) of thin-film structures, especially on thermally sensitive substrates in the field of semiconductor and display technology, as well as in other applications in which the implementation of wide radiation zones with an almost ideally constant radiation flux density results in high process productivity.

Advantages and expediencies of the invention also emerge from the subclaims and the following description of preferred exemplary embodiments with reference to the figures. Of these show:

1 shows a section of an irradiation arrangement with a radiation source according to a first embodiment of the invention in the form of a longitudinal sectional view,

2 shows a section of an irradiation arrangement with a radiation source according to a second embodiment of the invention in the manner of a longitudinal sectional illustration,

3 shows a section of an irradiation arrangement with a radiation source according to a third embodiment of the invention in the manner of a longitudinal sectional illustration,

Fig. 4 is a detailed representation of the execution of the

Lamp connection in the irradiation arrangement according to FIG. 3,

Fig. 5 is a perspective view of the in

3 shows a radiation arrangement shown in a detail, seen from the rear, 6A and 6B are a front view and a cross-sectional view of an end reflector or “head part” of the irradiation arrangement according to FIGS. 5 and

Fig. 7 is a schematic diagram in the manner of a side view to explain a radiation source according to a fourth embodiment of the invention.

FIG. 1 shows a section of an NIR radiation arrangement 10 for technological purposes with a plurality of in

Longitudinal direction and aligned with each other halogen filament lamps 11, each with an associated, elongated reflector 12, which is made of an extruded aluminum profile.

The basic structure of the reflector is known per se from EP 0 999 724 A2 by the applicant and is therefore not further explained here. In the following, reference will only be made to special cooling devices which are arranged inside or in the vicinity of the reflector.

As can be seen from the figure, the halogen filament lamp 11 has a tubular glass body 14, which has a base 13 at each of the two ends, in the center of which an elongated filament 15 extends. It increases with

Voltage and therefore with an increased operating temperature above 2500 K, in particular above 2900 K, operated and therefore provides radiation whose essential radiation component is in the near infrared range, especially in the wavelength range between 0.8 μm and 1.5 μm. The glass body 14 is bent approximately at right angles near its ends in such a way that an end section extending approximately at right angles to its course in the central part finally opens into the respective base 13. It can also be seen that the filament 15 itself towards the area of the "bend" increasingly thickened or its spiral structure is made denser.

The bending of the glass body 14 towards the reflector and the respective base in connection with the thickened or condensed design of the incandescent filament 15 ensures that the halogen filament lamp 11 supplies an essentially constant radiation flux density of the NIR radiation down to its lateral end regions , The proposed structure thus enables a series of radiation sources to be strung together to form a linearly extended radiation arrangement without significant drops in the radiation flux density at the joints.

A cooling water channel 16 is provided in the interior of the reflector 12 for cooling the reflector with cooling water W. A compressed air tube 17 with air nozzles 18 runs near the reflector surface near the ends of the glass body 14 which open into the base and through which cold compressed air A is applied to this region of the glass body. This cooling of the lamp ends - in combination with the heat dissipation capacity of the solid metal reflector - creates a steep T-gradient. This ensures that, despite vitreous body temperatures above 600 ° C, a base temperature around or below 200 ° C, which is important for the life of the radiation source, can be achieved.

FIG. 2 shows a further exemplary embodiment of an irradiation arrangement 20, in which components having the same function as FIG. 1 are also designated by reference numbers based on FIG. 1.

It can be seen that the reflector 22 here only extends below the center axis of the glass body 24 or the incandescent filament 25 and - unlike the arrangement 10 according to FIG. NEN has through the lined up reflectors 22 continuous cooling water channel 26.

With regard to the halogen filament lamp 21, there is an essential difference in the geometrically modified configuration of the bend in the region of the lamp ends. This is namely essentially C-shaped here, with the result that the base 23 are offset somewhat inwards relative to the outermost points of the glass body 24. On the one hand, this enables the halogen lamps 21 to come together even more closely and, on the other hand, the provision of relatively large cooling surfaces (flags) 29 on the lamp bases 23. In addition, tension-compensating and heat-conducting sockets 30 are provided in the area where the lamp ends pass through the reflector body , which ensure good heat transfer to the reflector body.

Through these measures together, a relatively steep T-gradient is also achieved in the area of the lamp ends, without the need for active compressed air cooling.

FIG. 3 shows a detail from a further NIR radiation arrangement 100, of which FIG. 5 shows an overall view in perspective and FIGS. 4 and 6A and 6B give detailed representations of the lamp connections or special end reflectors. Here too, reference numerals based on FIGS. 1 and 2 are used for functionally identical components.

The irradiation arrangement 100 differs from the previously described arrangements first of all by the use of conventional, tubular halogen filament lamps 101 with a cylindrical glass body 104 with a closure region (squeeze region) 103 and linear filament 105, which can best be seen in FIG. 4 Connection structure is held in an insulating support body 110 or plug contact holder 111. Also here is a reflector 102 from the The above-mentioned publication of generally known shape of the reflecting surface is available, which is made from an extruded aluminum profile. In the area of the lamp end of the filament lamp 101, an angled compressed air tube 107 with an air nozzle 108 directed towards the lamp holder is arranged.

Via the compressed air tube 107 and the air nozzle 108, cooling air is supplied to the area of the lamp holder in a similar manner and with a similar effect as in the arrangement described above, which is swirled around the holder and therefore cools it uniformly and efficiently.

As shown in FIG. 4, the halogen lamp 101 serving as the emitter of the NIR radiation is connected at the end via a connecting wire 112 and an approximately cylindrical plug contact 113. The plug contact 113 has a squeeze or

Crimping point 113a, via which it is connected to the strand 112, and an end region 113b with a reduced diameter and tapering into a truncated cone, an annular contact surface 113c being formed between this end region and its main part.

5 that the NIR irradiation arrangement 100 has a modular structure which, in addition to a reflector module 102 serving as a reflector for a plurality of halogen lamps, has two side wall modules 114, two head parts or end reflectors -Builds 115 and four corner pieces 116 includes. It can also be seen in which way the reflector module 102 carries the insulators 110 and plug contact holders 111 already shown in FIG. 3, and how the halogen lamps 101 are positioned in the irradiation arrangement. Furthermore, it is sketched that the parts can be screwed together via suitable mounting holes 117 in the corner pieces 116 (which of course each have a counterpart (not shown) in the side wall modules 114 and head parts 115). After all, part of one is all Component-passing cooling water channel 106 with a cooling water inlet 106a in one of the side parts 114 and a cooling water channel sealing area 106b at one of the corner pieces 116 is shown.

In the embodiment shown, the irradiation arrangement 100 is designed for the use of six halogen filament lamps 101 lying next to one another with the holder and contact shown in FIG. 4. In this case, the compressed air tube 107 shown in FIG. 3 can be used in an embodiment which has at least one air nozzle 108 at each lamp end.

As an alternative to this, the end reflector modules 115 are provided with an integrated cooling air supply in the manner shown in FIGS. 6A and 6B. This comprises an angled cooling air supply channel 107a ^Λ and a cooling air distribution channel 107b ^Λ connected to it and extending horizontally in the longitudinal direction of the head part 115. This is associated with six air nozzles 108, which are inclined relative to the adjacent inner surface of the head part 115. Furthermore, the head part is also penetrated by a section of the cooling water channel 106. The head part 115 in the example, like the other modules, in particular the reflector module 102, is made of solid aluminum, which combines good reflection and heat conduction properties.

7 shows a sketch of an NIR irradiation arrangement 200 according to a further embodiment of the invention, in which a so-called “internal air knife” is provided. With regard to the lamp and reflector geometry, this embodiment largely corresponds to that shown in FIGS. 1 to 5 and above Descriptions described, so that reference numbers based on the explanations described above are used here and the corresponding components are not described again. An essential special feature of the present embodiment is the presence of a quartz glass pane 218 on the side of the halogen lamp 201 facing away from the reflector 202. In certain processes, this quartz glass pane protects the emitter (the halogen lamp) against effects from the material to be processed. It is largely transparent to the NIR radiation of the halogen lamp, but nevertheless absorbs so much radiation that it heats up strongly during normal operation at high power.

Therefore, a supply device 208 for cold compressed air A for generating the "internal air knife" is also provided at one end of the halogen lamp reflector assembly. This is designed such that a laminar flow of compressed air flows from a flat outlet opening around a curved surface area into the space between the halogen lamp 201 and the quartz glass pane 218 are fed in. This compressed air flow exits the arrangement at the opposite end of the radiator assembly between the end face of the reflector 202 and the head part 215 arranged there at approximately right angles to its direction of flow along the quartz glass plate 218 and carries the heat away from it Quartz glass pane.

To improve cooling of the lamp ends, cooling surfaces (flags) 209 are firmly connected to the connecting strand 212 in a heat-conducting manner, for. B. welded. These are so inclined to the longitudinal axis of the halogen lamp that they protrude into the compressed air stream A and are washed by it and actively cooled. The compressed air flow, which primarily cools the quartz glass pane 218, thus also serves here as active lamp end cooling.

The embodiment of the invention is not limited to the examples and highlighted aspects described above, but is also possible within the scope of the claims in a large number of modifications which are within the scope of professional action. LIST OF REFERENCE NUMBERS

10; 20; 100; 200 NIR radiation arrangement

11; 21; 101; 201 halogen filament lamp

12 22; 102; 202 reflector (reflector module)

13 23 103; 203 connection

14 24 104 vitreous

15 25 105 incandescent filament

16 26; 106 cooling water channel

17 107 - compressed air tube

18 108 air nozzle

29 209 cooling surface (flag)

30 socket

103 crush area

106a cooling water inlet

106b cooling water channel sealing area

107a ^λ cooling air supply duct

107b Cooling air distribution duct

110 insulating support body

111 plug contact holder

112 connecting leads

113 plug contact

113a Pinch and Cri p point

113b end region

113c contact area

114 sidewall building block

115 head part (end reflector module)

116 end piece

117 mounting hole

208 air knife generating device

218 quartz glass

A compressed air

W cooling water

Claims

claims 1. radiation source (11; 21; 101) for electromagnetic radiation, the essential active component of which is in the near infrared range, in particular in the wavelength range between 0.8 μm and 1.5 μm, to form an elongated radiation zone, using an elongated halogen lamp ( 11; 21; 101), which is a tubular to which. Has ends with connections (13; 23; 112) provided glass body (14; 24; 104) with at least one filament (15; 25; 105), and an elongated reflector (12; 22; 102) characterized in that the ends of the glass body or contact holders (113) of the halogen lamp are arranged in heat-conducting contact with the reflector and / or the ends are assigned coolants (17, 18; 29; 107, 108; 107a ^x to 108) for heat dissipation in such a way that a steeper T-gradient between the central region of the vitreous body and its ends, in particular a T-drop from a vitreous body temperature above 600 ° C to an end temperature below 300 ° C, especially below 200 ° C, is generated. 2. Radiation source according to claim 1, characterized in that the coolant cooling fluid flow channels (17, 18; 107, 108; 107a ^λ to 108) for supplying a pressurized cooling fluid to the ends or near-end areas of the halogen lamp (11; 21; 101) and / or the regions of the reflector (12; 22; 102) adjacent to these. 3. Radiation source according to claim 2, characterized by at least one compressed air flow channel (17; 107; 107a 107b ^Λ ) in the reflector (12; 102) with outlet openings (18; 108) directed towards the ends or regions of the halogen lamp (11; 101) near the ends. 4. Radiation source according to claim 3, characterized by a plurality of compressed air flow channels (17; 107; 107a ^λ , 107b ^λ ) in the reflector (12; 102), each directed towards the ends or near-end regions of the halogen lamp (11; 101) Have outlet openings (18; 108), the outlet openings being arranged and designed such that compressed air supplied is swirled around the ends or regions near the end of the glass body. 5. Radiation source according to one of the preceding claims, g e k e n n z e i c h n e t d u r c h Water channels (16; 26; 106) in the reflector (12; 22; 102) that cross areas of the lamp adjacent to them. 6. Radiation source according to one of the preceding claims, g e k e n n z e i c h n e t d u r c h plug contact base (23), which heat conducting means (30) for heat dissipation to the reflector (22) are assigned. 7. Radiation source according to one of the preceding claims, that the coolants comprise heat radiation surfaces (29; 209) at the ends of the halogen lamp (21; 201), which in particular are connected in a heat-conducting manner to their connections (23). 8. Radiation source according to one of the preceding claims, characterized in that on the side facing away from the reflector (202) of the halogen lamp (201) has a protective pane (218) which is largely permeable to the emitted radiation and a cooling gas supply device (208), in particular compressed air supply device, at one end of the radiation source for supplying a cooling fluid (A) which runs between the halogen lamp and the protective pane are arranged for heat dissipation from the protective pane and from the area between the halogen lamp and protective pane. 9. Radiation source according to claim 7 and 8, so that the arrangement of the heat radiation surfaces (209) and the formation of the cooling gas supply device (208) are coordinated with one another such that the heat radiation surfaces are acted upon by the cooling fluid flow (A), in particular compressed air flow. 10. Radiation source according to one of the preceding claims, characterized in that the ends (13; 23; 103) of the halogen lamp (11; 21; 101) in the region of the reflector surface (12; 22; 102) or, based on the position of the halogen lamp, arranged behind this and the ends of the halogen lamp are bent towards the reflector. 11. Radiation source according to one of the preceding claims, characterized by end reflectors (115) which are arranged adjacent to the ends of the halogen lamp (101) and which extend at an obtuse or right angle from a main reflector running over most of the longitudinal extent of the halogen lamp and parallel to its longitudinal axis (102) extend in the direction of the longitudinal axis, in particular being pierced by it. 12. Radiation source according to claim 11 and one of claims 4 to 10, characterized in that at least one compressed air channel (107a, 107b ^λ ) extends into each end reflector (115) and this has at least one outlet opening (108), preferably a plurality of outlet openings. 13. Radiation source according to claim 13, characterized in that in the end reflectors (115) and in the main reflector (102) at least one compressed air channel (107a) and at least one outlet opening are provided, the outlet opening or outlet openings in the main reflector and the end reflectors different Determine the flow directions of the compressed air at the base (103) or glass body (104) of the halogen lamp (100). 14. Radiation source according to one of the preceding claims, so that the reflector (12; 22; 102) is designed as a solid extruded profile made of a material with high thermal conductivity, in particular aluminum or an aluminum alloy. 15. Radiation source according to claim 14 and one of claims 2 to 13, d a d u r c h g e k e n n z e i c h n e t that in the extruded profile cooling fluid flow channels (16; 26; 106) are pressed in. 16. Radiation source according to claim 14 or 15, characterized in that the cross section of the outer contour of the extruded profile in essentially rectangular and the cross-section of the reflector surface is essentially W-shaped, in particular two or three cooling fluid flow channels being pressed into the foot region of the "W". 17. Irradiation arrangement (10, 20) with a plurality of Radiation sources (11; 21) according to any one of claims 1 to 16, wherein at least two of the radiation sources are arranged one behind the other on a line, that is, that Cooling fluid flow channels (26) of the radiation sources (21) lined up in alignment are aligned with one another and connected to continuous flow channels, each of which has a connection for supplying cooling fluid to a first of the radiation sources lined up.