EP2981984B1 - Lamp - Google Patents

Description

The invention relates to a lamp with a stimulable by microwaves light source and a surrounding housing, which has at least one light exit opening. Such a lamp is also referred to as a microwave lamp and corresponds to a particular form of a gas discharge lamp. The corresponding energy supply for exciting the phosphor is in the form of microwave radiation. Such a luminaire usually comprises a quartz bulb, in which a noble gas is filled at low pressure. The quartz bulb is coated with metal halide salts. The corresponding microwave radiation is provided by a microwave generator or magnetron and generates a plasma by ionizing the corresponding inert gas filling. This plasma leads to evaporation of the corresponding metal-halide salt and through both together there is a corresponding light emission. Furthermore, influence on the emitted light spectrum by doping the coating are possible.

In known luminaires of this type, a light extraction took place, for example, via optical fibers or the like (see, for example US-B-6621195 . Figure 3b ). This was used in particular to allow the generation of the plasma by the microwave radiation, a corresponding EMC (Electromagnetic Compatibility) in the luminaire installation. D. h., It should not adversely affect other technical devices or living things corresponding electrical or electromagnetic effects, which may occur in the above-mentioned lamp in particular by the microwave radiation.

The invention has for its object to dispense with appropriate light guide or the like and to be able to decouple light from a corresponding luminaire housing cost and easily.

This object is achieved in that the corresponding Lichtaus- outlet opening of the lamp housing is assigned as a microwave shielding a labyrinth structure, which labyrinth structure is formed as a labyrinth plate with a plurality of extending obliquely to the light exit direction labyrinth passages.

The attachment of grid structures as microwave shields in front of the light exit window is from the above-mentioned or the further document WO-A-9856213 known.

A lattice or labyrinth structure in front of the light exit opening prevents that, apart from the desired light, no other radiation leaves the luminaire housing. As a rule, the luminaire housing is made of a metal manufactured, so that a corresponding microwave shield is only to be additionally arranged in the region of the light exit opening.

By this microwave shielding no additional coupling for light from the lamp housing is necessary. Instead, conventional devices can be used within the luminaire housing for light deflection and deflection in the direction of the light exit opening, wherein only in the region of the light exit opening a corresponding shielding against microwave radiation takes place, in particular with regard to EMC.

A corresponding grid or labyrinth structure is easy to arrange and inexpensive to produce. In particular, an adaptation to the shape and size of the light exit opening can be carried out in a simple manner.

In general, the light exit opening of a corresponding lamp housing is closed by a light-transparent cover, such as a glass or quartz plate. In order to be able to arrange the corresponding lattice or labyrinth structure in a simple manner in this connection, it can be arranged in the housing interior in the light exit direction in front of the corresponding light-transparent cover. Lattice and labyrinth structure impede only slightly or not at all a corresponding passage of the light radiation, while, however, given a secure microwave shielding.

In a simple example of a corresponding grid structure, this is formed from a perforated grid plate, in particular metal grid plate. Such is easy to produce, especially in the required size and shape.

In order to form only a slight obstacle, in particular with regard to the light emission, the grid plate may have a row and column arrangement of holes.

It is conceivable that the shape and size of the holes varies in accordance with the row or column direction. In a simple example, however, it is also possible that all holes have the same shape and the same diameter and are in particular circular holes.

As a rule, a microwave radiation of approximately 2.45 GHz is used, which can generate a plasma between the associated microwave antennas. To shield the corresponding microwave radiation, the hole size should be much smaller than the corresponding wavelength of the radiation. That is, the hole diameter would be a lot smaller than 12 cm, which corresponds to a wavelength of the microwave radiation of 2.45 GHz.

In the case of a corresponding grid plate with such a hole structure, it is furthermore designed as an edge filter or blocking filter, so that shielding is ensured for longer wavelengths, in particular in the area of the microwave radiation used.

In an analogous manner, the labyrinth structure according to the invention is designed as a labyrinth plate, in particular metal plate, with a multiplicity of labyrinth passages running at an angle to the light exit direction. The walls of the labyrinth passages may be reflective of light radiation so that they can exit through the labyrinth passages in the direction of the light exit opening. At the same time, the labyrinth passages are formed corresponding to the holes with a corresponding diameter which prevents passage of microwave radiation.

In a preferred embodiment, the labyrinth passages may have a length which varies outwardly from a central central axis and in particular increases in length.

In this context, it is generally advantageous if the central central axis is an axis of symmetry for the labyrinth passages, i. H. that the labyrinth plate is formed symmetrically with corresponding labyrinth passages above and below this symmetry axis.

As already stated, according to the invention, the rest of the construction of the luminaire or of the luminaire housing can take place as with other gas discharge lamps. In other words, for example, the light source can be assigned a light reflection device for deflecting light radiation emitted by the light source substantially in the direction of the light exit opening.

Such a light reflection device may be formed as a parabolic mirror or the like.

A simple assignment of the lattice or labyrinth plate to the light exit opening may result if grid or labyrinth plate is arranged on a rear side of the light-transparent cover facing the light source.

There is also the possibility that lattice and labyrinth plate are arranged interchangeable, not only an exchange of each grid plates and labyrinth plates can be done with each other, but also an exchange of a grid plate against a labyrinth plate and vice versa can take place.

In the following, examples of luminaires are explained in more detail with the microwave lamps having a lattice or labyrinth structure mentioned at the beginning with reference to the figures enclosed in the drawing.

Fig. 1

einen Längsschnitt durch ein Beispiel einer Leuchte Leuchte;

Fig. 2

eine Vorderansicht auf eine Gitterplatte als Gitterstruktur;

Fig. 3

eine Schrägansicht der Gitterstruktur nach Figur 2;

Fig. 4

einen Längsschnitt analog zur Figur 1 durch ein erstes Ausführungsbeispiel der Erfindung;

Fig. 5

eine Vorderansicht auf eine Labyrinthplatte als Labyrinthstruktur, und

Fig. 6

eine Schrägansicht der Labyrinthstruktur nach Figur 5.

Show it:

Fig. 1

a longitudinal section through an example of a lamp light;

Fig. 2

a front view of a grid plate as a grid structure;

Fig. 3

an oblique view of the grid structure after FIG. 2 ;

Fig. 4

a longitudinal section analogous to FIG. 1 by a first embodiment of the invention;

Fig. 5

a front view of a labyrinth plate as a labyrinth structure, and

Fig. 6

an oblique view of the labyrinth structure after FIG. 5 ,

In FIG. 1 a longitudinal section through a first of a lamp 1 is shown. This has a rectangular-shaped housing 4 in principle. This is shown only as an example and other forms of the lamp housing are also possible. Inside the housing 8, a microwave generator 3 is arranged in the form of a magnetron. This feeds microwave energy to corresponding antennas which are arranged inside a light source 2 with a corresponding quartz bulb or the like. A plasma of a corresponding noble gas is generated by the microwave radiation between the antennas, resulting in evaporation of metal halide salt applied to the glass or quartz glass bulb leads and generated from the noble gas plasma and the metal halide salt vapor light in a corresponding spectral range.

The light source 2 is partially surrounded by a light reflection device 18 in the form of, for example, a parabolic mirror. This directs light emitted by the light source 2 in the direction of a light exit opening 5 of the luminaire housing 4. The luminaire housing 4 is generally formed from a metal which represents a shield with respect to the microwave radiation. The light exit opening 5 is associated with a grid structure 6, which forms a corresponding microwave shield in the region of the light exit opening. The lattice structure 6 is arranged on a rear side 19 of a light-transparent cover 9 in the form of a glass or quartz plate 10. Light transparent cover 9 and grid structure 6 are arranged in a detachable end portion 22 of the lamp housing 4. The grating structure 6 is arranged in the light exit direction 20 in front of the light transparent cover 9, d. H. on whose in the direction of the light source 2 facing back 19th

The light exit opening is completely covered by the light transparent cover 9, wherein the corresponding grid structure 6 has analogous dimensions.

Furthermore, in FIG. 1 exemplified two light beams 21, which correspond to the maximum exit angle of light radiation from the light exit opening 5 of the lamp housing 4 substantially.

The grid structure 6 is formed as a grid plate 11 with a plurality of holes 12. These are, see also the FIGS. 2 and 3 arranged in rows and columns and each have the same shapes and the same diameter.

The diameter of the corresponding holes 12 is considerably smaller compared to the wavelength of the microwave radiation, for example, a microwave radiation of 2.45 GHz with a wavelength of about 12 cm is usable. The corresponding holes 12 only slightly obstruct an exit of the light beams 21, while the grating structure 6 forms a safe microwave shielding for the microwave radiation.

The grid plate 11 is formed from a simple to produce and inexpensive perforated metal plate, in a simple manner to appropriate sizes of the light exit opening or the light transparent cover 9 is customizable. Corresponding grid plates 11, as well as the further below-mentioned labyrinth plates 13 are not only in the substantially square shape to FIGS. 2, 3 . 5 and 6 but can be produced in the form of virtually any light exit opening with a corresponding light-transparent cover 9.

In the FIGS. 2 and 3 the grid structure 6 in the form of the grid plate 11 is shown in front view and in an oblique view from the front. In particular, the columns and rows arrangement of the corresponding holes 12 can be seen. In the edge region, the corresponding holes 12 may be formed only partially, see FIG. 2 the holes along the upper and lower edges of the grid plate eleventh

In FIG. 3 is the grid plate after FIG. 2 shown in an oblique view from the front. Again, the columns and rows arrangement and the partial formation of holes 12 along upper edges of the corresponding grid plate can be seen.

In FIG. 4 an embodiment of a lamp 1 according to the invention is shown. In this, the microwave generator 3 is not shown for simplicity. The structure of the corresponding lamp 1 corresponds to the FIG. 1 except for the use of a labyrinth structure 7 as a microwave shield instead of the grid structure 6. For further description of the lamp 1 according to FIG. 4 will follow the description FIG. 1 directed.

In FIG. 4 a plurality of light beams 21 are shown, which pass through the labyrinth structure 7 in the form of a labyrinth plate 13. For this passage, the labyrinth plate 13 has a plurality of labyrinth passages 14. These run obliquely outward relative to the light exit direction 20. Also, the labyrinth plate 13 is disposed on the corresponding rear side 19 of the light transparent cover 9, which covers the light exit opening 5 of the lamp housing.

The corresponding labyrinth passages 14 have on the exit side of the labyrinth plate 13 has an approximately rectangular cross-section, see FIG. 5 while extending in the direction of the light source 2 obliquely inward toward a central axis 15. The length of the corresponding labyrinth passages 14 increases from the central axis 15 to the outside, see the exemplified length 16 in FIG. 4 , Furthermore, the labyrinth plate 13 is symmetrical with corresponding labyrinth passages 14 formed to a running through the central axis 15 as the axis of symmetry 17 horizontal plane, see FIGS. 4 to 6 , D. h., That the labyrinth passages 14 in the upper region of the labyrinth plate 13 after FIG. 4 obliquely upward in the direction of light exit opening 5 and the corresponding labyrinth passages 14 in the lower part of the labyrinth plate 13 extend obliquely downward in the direction of the light exit opening 5.

The corresponding inner sides of the labyrinth passages 14 can be designed to be reflective for light rays, so that they do not constitute an obstacle to the exit of the light rays 21 from the light exit opening 5 substantially. The size and shape of the labyrinth passages 14 and in particular their inlet openings, which assign the light source 2, are substantially analogous to the size and diameter of the holes 12 after FIGS. 1 to 3 educated.

In FIGS. 5 and 6 is analogous to the FIGS. 2 and 3 a front view and a perspective view obliquely from the front of the corresponding labyrinth plate 13 is shown. The corresponding labyrinth passages 14 are arranged in rows and columns directly adjacent to one another. The corresponding labyrinth plate 13 with its labyrinth passages 14 is also formed of a metal having corresponding microwave shielding properties.

As explained above, the result is a safe, simple and cost-effective microwave shielding by directly the light exit opening or the light transparent cover 9 of the light exit opening 5 associated grating structure 6 and a labyrinth structure according to the invention 7. The corresponding openings in these structures are each formed sufficiently small to escape the exit Prevent microwave radiation. While the perforated grid plate 11 also forms a barrier filter at the same time, the corresponding labyrinth plate 13 can also be regarded as a resonant seal. That is, the corresponding labyrinth passages essentially form rectangular waveguides that are sufficiently small compared to the wavelength of the microwave radiation to prevent corresponding wave propagation along the labyrinth passages. A corresponding cut-off wavelength λ _C results, for example, according to the relationship λ _C = 2 xa, where a is the longer side of the corresponding waveguide cross-section, see for example FIG. 5 ,

The corresponding cut-off wavelength should be sufficiently small compared to the wavelength of the microwave radiation to be shielded.

There is also the possibility that the corresponding structures, see grid structure 6 or labyrinth structure 7, are interchangeable with each other as well as against each other, so that, for example, a grid structure could replace a corresponding labyrinth structure.

Claims (8)

1. A lamp (1) comprising a light source (2) that can be excited by microwaves to provide illumination and a housing (4) surrounding the light source, said housing having at least one light exit opening (5), characterized in that the light exit opening (5) has associated therewith a labyrinth structure (7) acting as a microwave shield, said labyrinth structure (7) being configured as a labyrinth panel (13) comprising a large number of labyrinth passages (14) which extend at an oblique angle to the light exit direction (20).
2. The lamp according to claim 1, characterized in that the labyrinth structure (7) is arranged in the housing interior (8) in front of a light-transparent cover (9), when seen in the light exit direction (20), said light-transparent cover (9) being in particular a glass or quartz plate (10).
3. The lamp according to claim 1 or 2, characterized in that the microwave shield is configured as an edge filter or a blocking filter.
4. The lamp according to one of the preceding claims, characterized in that the labyrinth passages (14) have a length (16) which varies and especially increases from a middle central axis (15) in an outward direction.
5. The lamp according to one of the preceding claims, characterized in that the middle central axis (15) is an axis of symmetry (17) for the labyrinth passages (14).
6. The lamp according to one of the preceding claims, characterized in that the light source (2) has associated therewith a light reflection unit (18) for deflecting light beams, which are emitted by said light source, substantially in the direction of the light exit opening (5).
7. The lamp according to one of the preceding claims, characterized in that the labyrinth panel (11, 13) is arranged on a back (19) of the light-transparent cover (9), said back (19) facing the light source (2).
8. The lamp according to one of the preceding claims, characterized in that the labyrinth panel (11, 13) is arranged such that it is exchangeable.

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