LUMINAIRE AND HOUSING FOR SUCH A LUMINAIRE WITH INTEGRATED LINE FOR TRANSMITTING SIGNALS

Abstract

A housing for a luminaire or an operating device for the luminaire, wherein the housing is configured to accommodate at least one electronic component and/or a light source, and comprising a conductive housing component (2). The housing includes at least one line (1, 1′, 1″, 1′″, 1″″) for transmitting electric high frequency signals or for transmitting and/or receiving radio waves. The transmission line is formed by arranging a dielectric layer (4, 4a, 4b, 9) and a conductor (3, 3 . . . 3c, 7) on the housing component (2) such that the conductive housing component (2) serves as a reference plane, and the conductive housing component (2) and the conductor (3, 3 . . . 3c, 7) sandwich the dielectric layer (4, 4a, 4b, 9).

Claims

1. A for a luminaire or an operating device for the luminaire, the housing being configured to accommodate at least one electronic component and/or a light source, and comprising a conductive housing component (2), wherein the housing includes at least one line (1, 1′, 1″, 1′″, 1″″) for transmitting electric high frequency signals or for transmitting and/or receiving radio waves, wherein at least one line (1, 1′, 1″, 1″′, 1″″) is formed by arranging a dielectric layer (4, 4a, 4b, 9) and a conductor (3, 3a . . . 3c, 7) on the housing component (2) such that the conductive housing component (2) serves as a ground plane, and the conductive housing component (2) and the conductor (3, 3a . . . 3c, 7) sandwich the dielectric layer (4, 4a, 4b, 9).

2. The housing according to claim 1, wherein the dielectric layer (4, 4a, 4b, 9) is at least partially established by a coating material.

3. The housing according to claim 1, wherein the dielectric layer (4, 4a, 4b, 9) is at least partially applied in form of an adhesive tape sticked to the housing component (2).

4. The housing according to claim 3, wherein the adhesive tape carries the conductor (3, 3 . . . 3c, 7) or the conductor (3, 3 . . . 3c, 7) comprises an adhesive coating.

5. The housing according to claim 1, wherein the conductor (3, 3 . . . 3c, 7) is applied by metal deposition, drawing conductive ink or attaching a metal foil.

6. The housing according to claim 1, wherein the dielectric layer (4, 4a, 4b, 9) and another dielectric layer sandwich the conductor (3, 3a, 3b, 7) so that the conductor (3, 3a, 3b, 7) is completely enclosed by the dielectric layer (4, 4a, 4b, 9) and the other dielectric layer.

7. The housing according to claim 1, wherein the housing component (2) comprises a flat section to which the dielectric layer (4, 4a, 4b) and the conductor (3, 3 . . . 3c, 7) are attached so as to establish a transmission line and/or an antenna, in particular a microstrip and a microstrip patch antenna, respectively.

8. The housing according to claim 7, wherein the antenna is a monopole antenna or a dipole antenna (13a, 13b).

9. The housing according to claim 7, wherein the transmission line is connected to the antenna.

10. The housing according to claim 7, wherein the transmission line forms a coplanar waveguide, in which the conductor (3, 3a . . . 3c, 7) together with a pair of return conductors (3, 3a . . . 3c, 7) sandwiching the conductor (3, 3a . . . 3c, 7) are arranged on the same side of the dielectric layer (4, 4a, 4b, 9) and the conductive housing component (2) serves a third return conductor.

11. The housing according to claim 7, wherein a plurality of transmission lines is arranged stacked, twisted or side by side.

12. The housing according to claim 7, wherein a projection (6, 6′) is formed on the housing component (2) projecting from the flat section from the same surface to which the dielectric layer (4, 4a, 4b) and the conductor (3, 3 . . . 3c b, 7) are attached.

13. The housing according to claim 1, wherein the line is (1″″) as a 3D-line with a part of the housing surrounding the conductor (3, 3 . . . 3c, 7) at least partially in cross section.

14. The housing according to claim 1, wherein at least one connector is provided contacting the line (1, 1′, 1″, 1′″, 1″″) and enabling another line (1, 1′, 1″, 1′″, 1″″) and/or electronic component to connect to the line (1, 1′, 1″, 1″′, 1″″) for feeding the line (1, 1′, 1″, 1″′, 1″′) with a signal and/or receiving a signal from the line (1, 1′, 1″, 1′″, 1″″).

15. The housing according to claim 1, wherein the housing comprises a plurality of housing components (2) commonly forming a ground plane of the line (1, 1′, 1″, 1″′, 1″″) established by commonly arranging a dielectric layer (4, 4a, 4b, 9) and a conductor (3, 3 . . . 3c, 7) on the housing components (2).

16. The housing according to claim 1, wherein the housing comprises a plurality of housing components (2) each forming a ground plane of respective line (1, 1′, 1″, 1′″, 1″″) sections wherein the line (1, 1′, 1″, 1″′, 1″″) sections of the plurality of housing components (2) are connected to realize line (1, 1′, 1″, 1′″, 1″″).

17. A luminaire comprising a housing according to claim 1, and further comprising at least one electronic component contacting the line (1, 1′, 1″, 1″′, 1″″) for transmitting and/or receiving a signal.

18. The luminaire according to claim 17, wherein ground of the electronic component is connected to the metallic housing component (2).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The structure of the housing including a line according to the invention in a plurality of different embodiments of such integrated lines transmitting microwave or radiofrequency signals in a luminaire will now be explained with reference to the attached drawings in which:

[0030] FIG. 1 shows a general structure of a line according to the invention using a conductive housing component as ground plane;

[0031] FIG. 2 shows a cross-section of the first embodiment of a line formed as a microstrip transmission line;

[0032] FIG. 3 shows a cross-section of a second embodiment adapted for transmitting differential signals;

[0033] FIG. 4 shows a cross-section of the third embodiment adapted for transmitting a differential signal with stacked transmission lines, or transmitting with a second reference on top;

[0034] FIG. 5 shows a cross-section of a fourth embodiment using a multilayer dielectric between the conductor and the conductive housing component;

[0035] FIG. 6 shows a cross-section of a sixth embodiment with projections adjacent to a signal conductor of the transmission line for improvement of electrical characteristics of the transmission line;

[0036] FIG. 7 illustrates the various positions at which the line can be attached to a housing of the luminaire and a further embodiment of a line formed as a 3D transmission line;

[0037] FIG. 8 illustrates a technique and a contacting element for contacting a transmission line using a spring loaded metal pin;

[0038] FIG. 9 illustrates a further contacting element using a metal spring for contacting a transmission line;

[0039] FIG. 10 shows an antenna attachable to the housing according to the invention; and

[0040] FIG. 11 shows a cross-section of a seventh embodiment of a line formed as a coplanar waveguide.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0041] The same features are denoted by the same reference signs throughout all figures.

[0042] The general structure of a line formed on a portion of a housing of a luminaire will now be explained with reference to FIG. 1. FIG. 1 shows a perspective illustration of a line 1 as one preferred example of the line according to the invention. The line 1 is generated using a conductive housing component 2 of a housing of a luminaire. Since the housing component can be any part of the conductive housing of the luminaire and for an easier understanding of the drawing, other components of the luminaire are not illustrated in the drawing.

[0043] The conductive housing component 2 may be, for example, a metallic body of luminaire, such as a light rail manufactured as extruded metal or deep drawn metal sheets. It is to be noted that the particular way of manufacturing the housing component is not relevant for the invention as long as a reasonable shaped surface is generated and the housing component is made of conductive material. Further, the surface of the conductive housing component 2 visible in FIG. 1 may be an outside surface of the conductive housing component or a surface oriented towards the inside of the housing of the luminaire

[0044] Using an outward oriented surface of the conductive housing component 2 has the advantage that the line may also be created after the conductive housing component has been mounted, for example, on a ceiling of the building. Of course, generating the line may also be performed on an inner surface of the conductive housing component 2. Examples for different positions on a housing of a luminaire will be explained in greater detail below with reference to FIG. 7.

[0045] The conductive housing component 2 has a flat surface on which a dielectric layer 4 is arranged. Application of the dielectric layer 4 may be achieved by sticking an adhesive tape to the surface of the conductive housing component 2. Other techniques may also be used as long as it can be ensured that the dimensions of the dielectric layer 4, particularly its thickness, can be controlled with sufficient accuracy.

[0046] A conductor 3 is attached on top of the surface of the dielectric layer 4 being oriented away from the conductive housing component 2. The conductor 3 may be made from arbitrary conductive material, in a preferred embodiment copper is used as conducting material for the conductor 3.

[0047] The dielectric layer 4 and the conductor 3 may be applied in a single manufacturing step. For example, the conductor 3 is attached to an adhesive tape made from dielectric material and forming, after sticking the adhesive tape to the surface of the conductive housing component 2, the dielectric layer 4. Alternatively, the dielectric layer 4 and the conductor 3 may be generated on the surface of the conductive housing component 2 in two successive manufacturing steps.

[0048] It is particularly preferred that the dielectric layer 4 is made from a material that is simultaneously used for protecting the surface of the conductive housing component 2 or even for optical reasons. Often, such protective layers are formed on the outer surface of a housing component but also on the inner surface of the housing of the luminaire in order to cover the entire surface of the housing. Preferred techniques are powder coating, spray painting, or anodizing. These techniques allow controlling the thickness of the layer with sufficient precision in order to use it, having knowledge of the dielectric constant of the material used, as the dielectric layer 4 for a line having a structure as shown in FIG. 1.

[0049] In case that such a coating of the conductive housing component 2 is used as a dielectric layer 4, the coated housing is then used as a substrate for attaching the conductor 3. The conductor 3 can be attached to the coated conductive housing component 2 by sticking an adhesive metal foil as conductor 3 on top of the coating, drawing a line using conductive ink or using vapor deposition techniques for sputtering metal particles to generate the conductor 3. Specifically the latter technique allows to use masks for generating arbitrary shapes of the conductor 3, thereby not only generating a line for transmitting microwave or radiofrequency signals along the extension of the housing of the luminaire but also creating electronic components such as power dividers or the like.

[0050] Electrical characteristics of lines that may typically be used for communication within a luminaire may typically be achieved with dimensions of the dielectric layer 4 and the conductor 3 that can easily be realized, even on small housing components and limited flat or almost flat portions of the housing component. For example, an impedance of 75 ohms for the transmission line can be achieved by using a metal luminaire housing component 2 with a powder coating having a thickness of 100 μm and a conductor thickness of 35 μm. A width of 0.075 mm of the conductor 3 then leads to an overall impedance of 75 Ohms assuming the dielectric constant of the powder coating being 4. The dimensions given above as an example can be realized by applying a selected foil or applying a single strand of wire having a diameter of 0.1 mm resulting in an impedance of 62 Ohms. As mentioned above already, alternative techniques for applying the metallic conductor 3 are physical or chemical vapor deposition, laser scribing or sintering, which all can be used in order to apply a metallic conductor 3 having the desired dimensions.

[0051] A cross-section of the simple version of a transmission line 1 (microstrip 1) shown in the perspective illustration in FIG. 1 is shown in FIG. 2. It is to be noted that in all the described and illustrated embodiments, the dimensions of the different layers (conductive housing component, dielectric layer and conductor) and, particularly the overall dimension of the conductive housing component 2 is not limiting. The skilled person will easily understand that the conductive housing component 2 may be any part of the housing that offers sufficient surface area to apply the dielectric layer 4 and the conductor 3. Although it is described to generate a transmission line by sandwiching the dielectric layer 4 between the conductor 3 and the conductive housing component 2 by attaching the dielectric layer 4 and the conductor 3 to a flat portion of the conductive housing component 2, the surface does not need to be entirely flat. Even slightly curved surfaces may be used, although, application of the dielectric layer 4 and the conductor 3 may be a little bit more difficult. However, even application of the dielectric layer 4 and the conductor 3 on a curved surface of the conductive housing component 2 is considered to create a transmission line 1 in the sense of the present invention.

[0052] Often it is desired to transmit differential signals from one component to another for communication within a luminaire. Thus, the structure as shown in FIG. 1 and FIG. 2 may be applied twice with defined and given distance between the 2 arrangements as it is shown in FIG. 3. The resulting transmission line 1′ is then used for transmission of differential signals for communication between connected electronic components. The general structure of each individual transmission line attached to the same conductive housing component 2 is the same and, particularly, the dimensions of the individual and neighbouring transmission lines are the same as it can be seen in FIG. 3. The respective components are indicated with “a” and “b” in the drawing. It is to be noted that it is also possible to use a common dielectric layer for both conductors. Such an arrangement is particularly useful when the coating of the metallic housing component 2 shall be used as the dielectric layer.

[0053] Even more than two lines or three may be arranged adjacent to each other. For example, a central line and two ground lines may be arranged adjacent to each other and running in parallel, in order to achieve an improved signal guidance.

[0054] Another alternative for creating a transmission line 1′″ for transmitting differential signal is shown in FIG. 4. Again, two transmission lines are generated, the different components of which are marked as “a” and “b”. However, this time the transmission lines are stacked thus arranging a second dielectric 4b on top of the first conductor 3a, followed by a second conductor 3b. It is apparent that due to the stacking the width of the successive layers stepwise decrease. Nevertheless, reasonable selection of the dielectric constants of the materials and also the further dimensions, namely the thicknesses of the layers allowed to adjust the overall impedance as desired.

[0055] All embodiments that have been explained so far make use of a single dielectric layer 4, 4a, 4b. However, application of a dielectric material can also lead to a plurality of dielectric sub layers , for example, in case that an adhesive tape made of a dielectric material is attached to a coating of the conductive housing component 2, which is already present at the end of manufacturing the respective housing part. Such an example is illustrated in cross-section in FIG. 5. The conductive housing component 2 is coated with a coating layer 5 to which the dielectric layer 4 is then attached followed by the conductor 3. The coating 5 and the dielectric layer 4 both builds sub-layers of the entire dielectric layer and have to be considered when designing the microstrip, in particular the thicknesses of the involved dielectric material sub-layers 4 and 5.

[0056] Further, while the width of the coating 5 is not limited by the structure of the transmission line, because the coating 5 is attached to the entire conductive housing component 2 first and independent from the layers attached finally, the attached dielectric sublayer 4 does not need to have the same extension in the width direction as the coating 5 constituting the first sub- layer.

[0057] The so far explained transmission lines assume the dimension in the width direction of the ground plane constituted by the conductive housing component 2 to be infinite with its flat surface on top of which the dielectric layer 4 and the conductor 3 are attached. However, it might be desired to provide projections projecting from the same surface of the conductive housing component 2 besides the arrangement of the dielectric layer 4 and the conductor 3.

[0058] Examples for such projections are shown in two different versions in FIG. 6. The left side of the arrangement of the dielectric layer 4 in the conductor 3 shows a projection 6 that may typically be formed when the conductive housing component 2 is made by extruding a metal, for example, aluminium for forming a metallic housing of a luminaire. On the right side in FIG. 6 an alternative version is illustrated, typically formed in case that a metallic housing of the luminaire is made by forming or deep drawing a metal sheet. The resulting projection 6′ results in the same electrical characteristics of the transmission line as the projection 6, assumed that the distance between the edges of the conductor 3 and the respective projection 6, 6′ is the same. Distance and height of such projection 6, 6′ may be adjusted depending on the desired electrical characteristics of the resulting transmission line 1. Further, it is to be noted that the height of the projections is also not limited to be substantially equal to the overall height of the arrangement of the dielectric layer 4 and the conductor 3 but can also be adjusted according to the specific requirements. In particular, the projections may be formed by an adjacent wall of the housing of the luminaire

[0059] Although FIG. 6 illustrates the projections 6, 6′ in combination with the simple form of a transmission line 1, it is evident that such projections 6, 6′ may also be provided in combination with any of the other above explained embodiments of transmission lines illustrated in FIGS. 3 to 5.

[0060] FIG. 7 schematically shows a cross-section of a lighting rail as an example of a housing for a luminaire. Such lighting track is known in the art and the plurality of such lighting tracks can be connected to each other in order to reach lengths of up to 100 m, for example. Such lengths are reached by connecting a plurality of modules (housings), whereby the connection of the modules does not necessarily connect the modules in only one dimension. Rather, various geometries of the connected modules can be used to generate different grid shapes, depending on circumstances in the building.

[0061] Preferred positions at which a transmission line according to one of the above-mentioned embodiments explained with reference to any of FIGS. 1 to 6 can be attached are indicated by characters “A”, “B”, “C” or “D”. It is preferred to arrange the transmission line on an inside of the housing as indicated by A or D in case that the dielectric layer 4 and the conductor 3 are attached to the conductive housing component 2 during manufacturing of the luminaire While the corrugation at position B and also the flat outer surface at position C may be used in the manufacturing process, it is evident that these positions are easily accessible even at a construction site after mounting the housing to generate a lighting structure in the building.

[0062] Attaching the dielectric layer 4 and the conductor 3 (or, of course, the plurality of dielectric layers and conductors as explained above with reference to the FIGS. 1 to 6) at the construction site has the advantage that a plurality of conductive housing components 2 may be mounted first to generate a modular housing and, then, the transmission line is generated by attaching the dielectric layer 4 and the conductor 3 extending over a plurality of connected conductive housing components 2.

[0063] In case that the arrangement of the conductive layer 4 and the conductor 3 is already applied in the manufacturing process, a connector is used in order to connect successive transmission lines established on individual modules.

[0064] FIG. 7 also illustrates a further embodiment of the line according to the present invention, which is built as a 3D-line with parts of the conductive housing component 2, indicated portion 8 at least partially surrounding a dielectric layer 9 enclosing a conductor 7. Since the sequence of the ground plane established by the conductive housing component 2 (including the projecting and surrounding portion 8), the dielectric layer 9 and the conductor 7 is still the same, it is evident that even in case of the 3D-line the conductor 7 and the conductive housing component 2 “sandwich” the dielectric layer 9.

[0065] It is to be noted that in the preferred and illustrated embodiment the dielectric layer 9 entirely encloses the conductor 7. However, for easier manufacturing the intermediates dielectric layer 9 may also only partially surround the conductor 7. The resulting structure resembles a coaxial line and provides comparable electrical characteristics.

[0066] Additionally or alternatively, the dielectric layer 9 may enclose the conductor 7 not along the full length of the conductor 7, but only in certain intervals in order to reduce losses. This may also achieve an improved transmission of signals at certain frequencies or frequency bands. This embodiment approximates, for example, dielectric layers formed like rings along the conductor 7.

[0067] It is also possible that, similar to the embodiments explained above, an adhesive tape is used as the dielectric layer 9 with the conductor 7 attached to the adhesive tape. The adhesive tape is then applied to the inside of a cavity created by the portion 8 of the conductive housing component 2. Similar to the explanations given above with reference to FIG. 6, such portions 8 of the conductive housing component 2 may positively influence the electrical characteristics of the resulting line for transmitting communication signals in the housing of the luminaire.

[0068] The luminaire using the conductive housing component 2 comprises one or more electronic components, not shown in the figures. The electronic components may serve different purposes in the luminaire or a lighting system. Apparently, the electronic component may be used for controlling an light source of the luminaire. For transmitting or receiving communication signals, the electronic component contacts the conductor 3 so that the transmission line 1 is used for transmitting and receiving communication signals. The transmission of communication signals may be performed between a plurality of electronic components of the same luminaire but also between electronic components arranged in different parts for different luminaires

[0069] An electronic component may also be a transceiver coupled to the transmission line according to the invention and capable of transmitting and receiving signals via different communication channels, for example, wirelessly with remote further electronic components. The transmission lines 1, 1′, . . . as illustrated and explained above are preferably used to establish a bus system within a lighting arrangement such as a light track.

[0070] For contacting the conductor 3, 3a, 3b established techniques may be used like an elastic metal contact (spring contact), a conductive glue, or a mechanical solution like a spring arrangement pressing a contacting pin on the surface of the conductor 3, 3a, 3b. FIGS. 8 and 9 illustrate techniques for contacting the conductor 3, 3a, 3b. Those techniques are generally known in the art. Using these contacting elements in combination with the transmission line 1 enables connecting signal sources (transmitter) and signal sinks (receiver) for the high frequency signal transmitted over the transmission line 1 to the conductor 3, 3a, 3b of the transmission line 1.

[0071] Alternatively or additionally, the contacting elements may connect the conductors 3, 3a, 3b of individual luminaires with each other in order to achieve transmission of high frequency signals over increased distances and a plurality of luminaires.

[0072] FIG. 8 illustrates a technique for contacting a transmission line using a spring loaded metal pin 10 as the contacting element. Such spring loaded metal pin 10 is sometimes referenced as pogo pin™.

[0073] FIG. 9 illustrates an alternative technique for contacting a transmission line using a metal spring 11.1 arranged in a contacting assembly 10 as an alternate embodiment of a contacting element.

[0074] With the conductors 3, 3a, 3b, 7 shown in FIGS. 1 to 9, electrical signals are transmitted from a first electronic component (first contacting element) to a second electronic component (second contacting element), wherein the conductor 3, 3a, 3b, 7 is a part of the transmission line formed by the dielectric layer 4, 4a, 4b, 9, the conductor 3, 3a, 3b, 7 and the ground plane of the conductive housing component 2.

[0075] Alternatively or in addition, one or a plurality of conductors 3, 3a, 3b, 7 arranged on the conductive housing component 2 via the dielectric layer 4, 4a, 4b, 9 as shown in FIGS. 1 to 9 can be an antenna element of an antenna, with which signals can be transmitted and/or received.

[0076] Alternatively or in addition, at least one conductor 3, 3a, 3b, 7 arranged on the conductive housing component 2 via the dielectric layer 4, 4a, 4b, 9 as shown in FIGS. 1 to 9 can be an antenna element. The antenna comprising the antenna element(s) is placed inside or outside the housing and is configured to transmit and/or receive signals.

[0077] The antenna can be a monopole antenna, a dipole antenna or a patch antenna, wherein the conductive housing component 2 serves as the ground plane of the antenna and the one or more conductors 3, 3a, 3b, 7 are arranged linear, rectangular, circular and/or triangular on the dielectric layer 4, 4a, 4b, 9.

[0078] The conductors 3, 3a, 3b, 7 of the antenna can be connected to an electronic component or a connection cable by the contacting element shown in FIG. 8 or 9. Alternatively, the antenna can be (seamlessly) connected to a transmission line formed by the conductors 3, 3a, 3b, 7, whereas the transmission line is connected to the electronic component.

[0079] FIG. 10 shows a perspective illustration of a dipole antenna in the form of an adhesive pad attachable to the inside or outside of the conductive housing component 2. The pad is formed of a flexible material and comprises the dielectric layer 4, which is a single-sided adhesive tape, and two conductors 3a, 3b fixed on the dielectric layer 4. Each conductor 3a, 3b comprises an electrical contact 12a, 12b formed at its free end and one of the two antenna elements 13a, 13b formed at its other end. The electrical contacts 12a, 12b provide an increased contact surface for the contacting elements. The part of the pad including the electrical contacts 12a, 12b can be inserted into the housing, whereas the part including the two antenna elements 13a, 13b can be attached to the outside of the housing.

[0080] After the dipole antenna shown in FIG. 10 is attached to the conductive housing component 2, the housing inclusive of the antenna can be coated (powder coating, spray painting, or anodizing) to produce uniform colouring and/or to provide a further dielectric layer on the top of the two conductors 3a, 3b that are arranged on the dielectric layer 4.

[0081] FIG. 10 shows a cross-section of a transmission line formed as a coplanar-backed waveguide using the conductive housing component 2. The transmission line consists of a first conductor 3a arranged on the dielectric layer 4, together with a pair of return conductors 3b, 3c, one to either side of the first conductor 3a, and the conductive housing component 2 serving as a third return conductor. All three conductors 3a . . . 3c are on the same side of the dielectric layer 4, and hence are coplanar, wherein the conductive housing component 2 covers the entire back-face of the dielectric layer 4. The return conductors 3b, 3c are separated from the central first conductor 3a by a respective gap 14a, 14b, which has an unvarying width along the length of the transmission line.

[0082] The housing or the conductive housing component 2 shown in FIGS. 1 to 9 and 11 is a housing/housing component of a luminaire. Alternatively, the housing can be a housing of an operating device for an illuminant (e.g. a LED driver or a ballast for fluorescent lamps), a LED module or a sensor device.